Search results for: The Great Gatsby
274 Procedure for Monitoring the Process of Behavior of Thermal Cracking in Concrete Gravity Dams: A Case Study
Authors: Adriana de Paula Lacerda Santos, Bruna Godke, Mauro Lacerda Santos Filho
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Several dams in the world have already collapsed, causing environmental, social and economic damage. The concern to avoid future disasters has stimulated the creation of a great number of laws and rules in many countries. In Brazil, Law 12.334/2010 was created, which establishes the National Policy on Dam Safety. Overall, this policy requires the dam owners to invest in the maintenance of their structures and to improve its monitoring systems in order to provide faster and straightforward responses in the case of an increase of risks. As monitoring tools, visual inspections has provides comprehensive assessment of the structures performance, while auscultation’s instrumentation has added specific information on operational or behavioral changes, providing an alarm when a performance indicator exceeds the acceptable limits. These limits can be set using statistical methods based on the relationship between instruments measures and other variables, such as reservoir level, time of the year or others instruments measuring. Besides the design parameters (uplift of the foundation, displacements, etc.) the dam instrumentation can also be used to monitor the behavior of defects and damage manifestations. Specifically in concrete gravity dams, one of the main causes for the appearance of cracks, are the concrete volumetric changes generated by the thermal origin phenomena, which are associated with the construction process of these structures. Based on this, the goal of this research is to propose a monitoring process of the thermal cracking behavior in concrete gravity dams, through the instrumentation data analysis and the establishment of control values. Therefore, as a case study was selected the Block B-11 of José Richa Governor Dam Power Plant, that presents a cracking process, which was identified even before filling the reservoir in August’ 1998, and where crack meters and surface thermometers were installed for its monitoring. Although these instruments were installed in May 2004, the research was restricted to study the last 4.5 years (June 2010 to November 2014), when all the instruments were calibrated and producing reliable data. The adopted method is based on simple linear correlations procedures to understand the interactions among the instruments time series, verifying the response times between them. The scatter plots were drafted from the best correlations, which supported the definition of the limit control values. Among the conclusions, it is shown that there is a strong or very strong correlation between ambient temperature and the crack meters and flowmeters measurements. Based on the results of the statistical analysis, it was possible to develop a tool for monitoring the behavior of the case study cracks. Thus it was fulfilled the goal of the research to develop a proposal for a monitoring process of the behavior of thermal cracking in concrete gravity dams.Keywords: concrete gravity dam, dams safety, instrumentation, simple linear correlation
Procedia PDF Downloads 288273 Carbon Aerogels with Tailored Porosity as Cathode in Li-Ion Capacitors
Authors: María Canal-Rodríguez, María Arnaiz, Natalia Rey-Raap, Ana Arenillas, Jon Ajuria
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The constant demand of electrical energy, as well as the increase in environmental concern, lead to the necessity of investing in clean and eco-friendly energy sources that implies the development of enhanced energy storage devices. Li-ion batteries (LIBs) and Electrical double layer capacitors (EDLCs) are the most widespread energy systems. Batteries are able to storage high energy densities contrary to capacitors, which main strength is the high-power density supply and the long cycle life. The combination of both technologies gave rise to Li-ion capacitors (LICs), which offers all these advantages in a single device. This is achieved combining a capacitive, supercapacitor-like positive electrode with a faradaic, battery-like negative electrode. Due to the abundance and affordability, dual carbon-based LICs are nowadays the common technology. Normally, an Active Carbon (AC) is used as the EDLC like electrode, while graphite is the material commonly employed as anode. LICs are potential systems to be used in applications in which high energy and power densities are required, such us kinetic energy recovery systems. Although these devices are already in the market, some drawbacks like the limited power delivered by graphite or the energy limiting nature of AC must be solved to trigger their used. Focusing on the anode, one possibility could be to replace graphite with Hard Carbon (HC). The better rate capability of the latter increases the power performance of the device. Moreover, the disordered carbonaceous structure of HCs enables storage twice the theoretical capacity of graphite. With respect to the cathode, the ACs are characterized for their high volume of micropores, in which the charge is storage. Nevertheless, they normally do not show mesoporous, which are really important mainly at high C-rates as they act as transport channels for the ions to reach the micropores. Usually, the porosity of ACs cannot be tailored, as it strongly depends on the precursor employed to get the final carbon. Moreover, they are not characterized for having a high electrical conductivity, which is an important characteristic to get a good performance in energy storage applications. A possible candidate to substitute ACs are carbon aerogels (CAs). CAs are materials that combine a high porosity with great electrical conductivity, opposite characteristics in carbon materials. Furthermore, its porous properties can be tailored quite accurately according to with the requirements of the application. In the present study, CAs with controlled porosity were obtained from polymerization of resorcinol and formaldehyde by microwave heating. Varying the synthesis conditions, mainly the amount of precursors and pH of the precursor solution, carbons with different textural properties were obtained. The way the porous characteristics affect the performance of the cathode was studied by means of a half-cell configuration. The material with the best performance was evaluated as cathode in a LIC versus a hard carbon as anode. An analogous full LIC made by a high microporous commercial cathode was also assembled for comparison purposes.Keywords: li-ion capacitors, energy storage, tailored porosity, carbon aerogels
Procedia PDF Downloads 161272 Unifying RSV Evolutionary Dynamics and Epidemiology Through Phylodynamic Analyses
Authors: Lydia Tan, Philippe Lemey, Lieselot Houspie, Marco Viveen, Darren Martin, Frank Coenjaerts
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Introduction: Human respiratory syncytial virus (hRSV) is the leading cause of severe respiratory tract infections in infants under the age of two. Genomic substitutions and related evolutionary dynamics of hRSV are of great influence on virus transmission behavior. The evolutionary patterns formed are due to a precarious interplay between the host immune response and RSV, thereby selecting the most viable and less immunogenic strains. Studying genomic profiles can teach us which genes and consequent proteins play an important role in RSV survival and transmission dynamics. Study design: In this study, genetic diversity and evolutionary rate analysis were conducted on 36 RSV subgroup B whole genome sequences and 37 subgroup A genome sequences. Clinical RSV isolates were obtained from nasopharyngeal aspirates and swabs of children between 2 weeks and 5 years old of age. These strains, collected during epidemic seasons from 2001 to 2011 in the Netherlands and Belgium by either conventional or 454-sequencing. Sequences were analyzed for genetic diversity, recombination events, synonymous/non-synonymous substitution ratios, epistasis, and translational consequences of mutations were mapped to known 3D protein structures. We used Bayesian statistical inference to estimate the rate of RSV genome evolution and the rate of variability across the genome. Results: The A and B profiles were described in detail and compared to each other. Overall, the majority of the whole RSV genome is highly conserved among all strains. The attachment protein G was the most variable protein and its gene had, similar to the non-coding regions in RSV, more elevated (two-fold) substitution rates than other genes. In addition, the G gene has been identified as the major target for diversifying selection. Overall, less gene and protein variability was found within RSV-B compared to RSV-A and most protein variation between the subgroups was found in the F, G, SH and M2-2 proteins. For the F protein mutations and correlated amino acid changes are largely located in the F2 ligand-binding domain. The small hydrophobic phosphoprotein and nucleoprotein are the most conserved proteins. The evolutionary rates were similar in both subgroups (A: 6.47E-04, B: 7.76E-04 substitution/site/yr), but estimates of the time to the most recent common ancestor were much lower for RSV-B (B: 19, A: 46.8 yrs), indicating that there is more turnover in this subgroup. Conclusion: This study provides a detailed description of whole RSV genome mutations, the effect on translation products and the first estimate of the RSV genome evolution tempo. The immunogenic G protein seems to require high substitution rates in order to select less immunogenic strains and other conserved proteins are most likely essential to preserve RSV viability. The resulting G gene variability makes its protein a less interesting target for RSV intervention methods. The more conserved RSV F protein with less antigenic epitope shedding is, therefore, more suitable for developing therapeutic strategies or vaccines.Keywords: drug target selection, epidemiology, respiratory syncytial virus, RSV
Procedia PDF Downloads 408271 Starting the Hospitalization Procedure with a Medicine Combination in the Cardiovascular Department of the Imam Reza (AS) Mashhad Hospital
Authors: Maryamsadat Habibi
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Objective: pharmaceutical errors are avoidable occurrences that can result in inappropriate pharmaceutical use, patient harm, treatment failure, increased hospital costs and length of stay, and other outcomes that affect both the individual receiving treatment and the healthcare provider. This study aimed to perform a reconciliation of medications in the cardiovascular ward of Imam Reza Hospital in Mashhad, Iran, and evaluate the prevalence of medication discrepancies between the best medication list created for the patient by the pharmacist and the medication order of the treating physician there. Materials & Methods: The 97 patients in the cardiovascular ward of the Imam Reza Hospital in Mashhad were the subject of a cross-sectional study from June to September of 2021. After giving their informed consent and being admitted to the ward, all patients with at least one underlying condition and at least two medications being taken at home were included in the study. A medical reconciliation form was used to record patient demographics and medical histories during the first 24 hours of admission, and the information was contrasted with the doctors' orders. The doctor then discovered medication inconsistencies between the two lists and double-checked them to separate the intentional from the accidental anomalies. Finally, using SPSS software version 22, it was determined how common medical discrepancies are and how different sorts of discrepancies relate to various variables. Results: The average age of the participants in this study was 57.6915.84 years, with 57.7% of men and 42.3% of women. 95.9% of the patients among these people encountered at least one medication discrepancy, and 58.9% of them suffered at least one unintentional drug cessation. Out of the 659 medications registered in the study, 399 cases (60.54%) had inconsistencies, of which 161 cases (40.35%) involved the intentional stopping of a medication, 123 cases (30.82%) involved the stopping of a medication unintentionally, and 115 cases (28.82%) involved the continued use of a medication by adjusting the dose. Additionally, the category of cardiovascular pharmaceuticals and the category of gastrointestinal medications were found to have the highest medical inconsistencies in the current study. Furthermore, there was no correlation between the frequency of medical discrepancies and the following variables: age, ward, date of visit, type, and number of underlying diseases (P=0.13), P=0.61, P=0.72, P=0.82, P=0.44, and so forth. On the other hand, there was a statistically significant correlation between the number of medications taken at home (P=0.037) and the prevalence of medical discrepancies with gender (P=0.029). The results of this study revealed that 96% of patients admitted to the cardiovascular unit at Imam Reza Hospital had at least one medication error, which was typically an intentional drug discontinuance. According to the study's findings, patients admitted to Imam Reza Hospital's cardiovascular ward have a great potential for identifying and correcting various medication discrepancies as well as for avoiding prescription errors when the medication reconciliation method is used. As a result, it is essential to carry out a precise assessment to achieve the best treatment outcomes and avoid unintended medication discontinuation, unwanted drug-related events, and drug interactions between the patient's home medications and those prescribed in the hospital.Keywords: drug combination, drug side effects, drug incompatibility, cardiovascular department
Procedia PDF Downloads 79270 Elastoplastic Modified Stillinger Weber-Potential Based Discretized Virtual Internal Bond and Its Application to the Dynamic Fracture Propagation
Authors: Dina Kon Mushid, Kabutakapua Kakanda, Dibu Dave Mbako
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The failure of material usually involves elastoplastic deformation and fracturing. Continuum mechanics can effectively deal with plastic deformation by using a yield function and the flow rule. At the same time, it has some limitations in dealing with the fracture problem since it is a theory based on the continuous field hypothesis. The lattice model can simulate the fracture problem very well, but it is inadequate for dealing with plastic deformation. Based on the discretized virtual internal bond model (DVIB), this paper proposes a lattice model that can account for plasticity. DVIB is a lattice method that considers material to comprise bond cells. Each bond cell may have any geometry with a finite number of bonds. The two-body or multi-body potential can characterize the strain energy of a bond cell. The two-body potential leads to the fixed Poisson ratio, while the multi-body potential can overcome the limitation of the fixed Poisson ratio. In the present paper, the modified Stillinger-Weber (SW), a multi-body potential, is employed to characterize the bond cell energy. The SW potential is composed of two parts. One part is the two-body potential that describes the interatomic interactions between particles. Another is the three-body potential that represents the bond angle interactions between particles. Because the SW interaction can represent the bond stretch and bond angle contribution, the SW potential-based DVIB (SW-DVIB) can represent the various Poisson ratios. To embed the plasticity in the SW-DVIB, the plasticity is considered in the two-body part of the SW potential. It is done by reducing the bond stiffness to a lower level once the bond reaches the yielding point. While before the bond reaches the yielding point, the bond is elastic. When the bond deformation exceeds the yielding point, the bond stiffness is softened to a lower value. When unloaded, irreversible deformation occurs. With the bond length increasing to a critical value, termed the failure bond length, the bond fails. The critical failure bond length is related to the cell size and the macro fracture energy. By this means, the fracture energy is conserved so that the cell size sensitivity problem is relieved to a great extent. In addition, the plasticity and the fracture are also unified at the bond level. To make the DVIB able to simulate different Poisson ratios, the three-body part of the SW potential is kept elasto-brittle. The bond angle can bear the moment before the bond angle increment is smaller than a critical value. By this method, the SW-DVIB can simulate the plastic deformation and the fracturing process of material with various Poisson ratios. The elastoplastic SW-DVIB is used to simulate the plastic deformation of a material, the plastic fracturing process, and the tunnel plastic deformation. It has been shown that the current SW-DVIB method is straightforward in simulating both elastoplastic deformation and plastic fracture.Keywords: lattice model, discretized virtual internal bond, elastoplastic deformation, fracture, modified stillinger-weber potential
Procedia PDF Downloads 91269 Powered Two-Wheeler Rider’s Comfort over Road Sections with Skew Superelevation
Authors: Panagiotis Lemonakis, Nikolaos Moisiadis, Andromachi Gkoutzini, George Kaliabetsos, Nikos Eliou
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The proper surface water drainage not only affects vehicle movement dynamics but also increases the likelihood of an accident due to the fact that inadequate drainage is associated with potential hydroplaning and splash and spray driving conditions. Nine solutions have been proposed to address hydroplaning in sections with inadequate drainage, e.g., augmented superelevation and longitudinal rates, reduction of runoff length, and skew superelevation. The latter has been extensively implemented in highways recently, enhancing the safety level in the applied road segments in regards to the effective drainage of the rainwater. However, the concept of the skew superelevation has raised concerns regarding the driver’s comfort when traveling over skew superelevation sections, particularly at high speeds. These concerns alleviated through the concept of the round-up skew superelevation, which reduces both the lateral and the vertical acceleration imposed to the drivers and hence, improves comfort and traffic safety. Various research studies aimed at investigating driving comfort by evaluating the lateral and vertical accelerations sustained by the road users and vehicles. These studies focused on the influence of the skew superelevation to passenger cars, buses and trucks, and the drivers themselves, traveling at a certain range of speeds either below or above the design speed. The outcome of these investigations which based on the use of simulations, revealed that the imposed accelerations did not exceed the statutory thresholds even when the travelling speed was significantly greater than the design speed. Nevertheless, the effect of the skew superelevation to other vehicle types for instance, motorcycles, has not been investigated so far. The present research study aims to bridge this gap by investigating the impact of skew superelevation on the motorcycle rider’s comfort. Power two-wheeler riders are susceptible to any changes on the pavement surface and therefore a comparison between the traditional superelevation practice and the skew superelevation concept is of paramount importance. The methodology based on the utilization of sophisticated software in order to design the model of the road for several values of the longitudinal slope. Based on the values of the slopes and the use of a mathematical equation, the accelerations imposed on the wheel of the motorcycle were calculated. Due to the fact that the final aim of the study is the influence of the skew superelevation to the rider, it was deemed necessary to convey the calculated accelerations from the wheel to the rider. That was accomplished by implementing the quarter car suspension model adjusted to the features of two-wheeler vehicles. Finally, the accelerations derived from this process evaluated according to specific thresholds originated from the International Organization for Standardization, which correspond to certain levels of comfort. The most important conclusion drawn is that the comfort of the riders is not dependent on the form of road gradient to a great extent due to the fact that the vertical acceleration imposed to the riders took similar values regardless of the value of the longitudinal slope.Keywords: acceleration, comfort, motorcycle, safety, skew superelevation
Procedia PDF Downloads 149268 Characterization of Extra Virgin Olive Oil from Olive Cultivars Grown in Pothwar, Pakistan
Authors: Abida Mariam, Anwaar Ahmed, Asif Ahmad, Muhammad Sheeraz Ahmad, Muhammad Akram Khan, Muhammad Mazahir
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The plant olive (Olea europaea L.) is known for its commercial significance due to nutritional and health benefits. Pakistan is ranked 4th among countries who import olive oil whereas, 70% of edible oil is imported to fulfil the needs of the country. There exists great potential for Olea europaea cultivation in Pakistan. The popularity and cultivation of olive fruit has increased in recent past due to its high socio-economic and health significance. There exist almost negligible data on the chemical composition of extra virgin olive oil extracted from cultivars grown in Pothwar, an area with arid climate conducive for growth of olive trees. Keeping in view these factors a study has been conducted to characterize the olive oil extracted from olive cultivars collected from Pothwar regions of Pakistan for their nutritional potential and value addition. Ten olive cultivars (Gemlik, Coratina, Sevillano, Manzanilla, Leccino, Koroneiki, Frantoio, Arbiquina, Earlik and Ottobratica) were collected from Barani Agriculture Research Institute, Chakwal. Extra Virgin Olive Oil (EVOO) was extracted by cold pressing and centrifuging of olive fruits. The highest amount of oil was yielded in Coratina (23.9%) followed by Frantoio (23.7%), Koroneiki (22.8%), Sevillano (22%), Ottobratica (22%), Leccino (20.5%), Arbiquina (19.2%), Manzanilla (17.2%), Earlik (14.4%) and Gemllik (13.1%). The extracted virgin olive oil was studied for various physico- chemical properties and fatty acid profile. The Physical and chemical properties i.e., characteristic odor and taste, light yellow color with no foreign matter, insoluble impurities (≤0.08), fee fatty acid (0.1 to 0.8), acidity (0.5 to 1.6 mg/g acid), peroxide value (1.5 to 5.2 meqO2/kg), Iodine value (82 to 90), saponification value (186 to 192 mg/g) and unsaponifiable matter (4 to 8g/kg), ultraviolet spectrophotometric analysis (k232 and k270), showed values in the acceptable range, established by PSQCA and IOOC set for extra virgin olive oil. Olive oil was analyzed by Near Infra-Red spectrophotometry (NIR) for fatty acids sin olive oils which were found as: palmitic, palmitoleic, stearic, oleic, linoleic and alpha-linolenic. Major fatty acid was Oleic acid in the highest percentage ranging from (55 to 66.1%), followed by linoleic (10.4 to 20.4%), palmitic (13.8 to 19.5%), stearic (3.9 to 4.4%), palmitoleic (0.3 to 1.7%) and alpha-linolenic (0.9 to 1.7%). The results were significant with differences in parameters analyzed for all ten cultivars which confirm that genetic factors are important contributors in the physico-chemical characteristics of oil. The olive oil showed superior physical and chemical properties and recommended as one of the healthiest forms of edible oil. This study will help consumers to be more aware of and make better choices of healthy oils available locally thus contributing towards their better health.Keywords: characterization, extra virgin olive oil, oil yield, fatty acids
Procedia PDF Downloads 91267 Common Misconceptions around Human Immunodeficiency Virus in Rural Uganda: Establishing the Role for Patient Education Leaflets Using Patient and Staff Surveys
Authors: Sara Qandil, Harriet Bothwell, Lowri Evans, Kevin Jones, Simon Collin
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Background: Uganda suffers from high rates of HIV. Misconceptions around HIV are known to be prevalent in Sub-Saharan Africa (SSA). Two of the most common misconceptions in Uganda are that HIV can be transmitted by mosquito bites or from sharing food. The aim of this project was to establish the local misconceptions around HIV in a Central Ugandan population, and identify if there is a role for patient education leaflets. This project was undertaken as a student selected component (SSC) offered by Swindon Academy, based at the Great Western Hospital, to medical students in their fourth year of the undergraduate programme. Methods: The study was conducted at Villa Maria Hospital; a private, rural hospital in Kalungu District, Central Uganda. 36 patients, 23 from the hospital clinic and 13 from the community were interviewed regarding their understanding of HIV and by what channels they had obtained this understanding. Interviews were conducted using local student nurses as translators. Verbal responses were translated and then transcribed by the researcher. The same 36 patients then undertook a 'misconception' test consisting of 35 questions. Quantitative data was analysed using descriptive statistics and results were scored based on three components of 'transmission knowledge', 'prevention knowledge' and 'misconception rejection'. Each correct response to a question was scored one point, otherwise zero e.g. correctly rejecting a misconception scored one point, but answering ‘yes’ or ‘don’t know’ scored zero. Scores ≤ 27 (the average score) were classified as having ‘poor understanding’. Mean scores were compared between participants seen at the HIV clinic and in the community, and p-values (including Fisher’s exact test) were calculated using Stata 2015. Level of significance was set at 0.05. Interviews with 7 members of staff working in the HIV clinic were undertaken to establish what methods of communication are used to educate patients. Interviews were transcribed and thematic analysis undertaken. Results: The commonest misconceptions which failed to be rejected included transmission of HIV by kissing (78%), mosquitoes (69%) and touching (36%). 33% believed HIV may be prevented by praying. The overall mean scores for transmission knowledge (87.5%) and prevention knowledge (81.1%) were better than misconception rejection scores (69.3%). HIV clinic respondents did tend to have higher scores, i.e. fewer misconceptions, although there was statistical evidence of a significant difference only for prevention knowledge (p=0.03). Analysis of the qualitative data is ongoing but several patients expressed concerns about not being able to read and therefore leaflets not having a helpful role. Conclusions: Results from this paper identified that a high proportion of the population studied held misconceptions about HIV. Qualitative data suggests that there may be a role for patient education leaflets, if pictorial-based and suitable for those with low literacy skill.Keywords: HIV, human immunodeficiency virus, misconceptions, patient education, Sub-Saharan Africa, Uganda
Procedia PDF Downloads 249266 Averting a Financial Crisis through Regulation, Including Legislation
Authors: Maria Krambia-Kapardis, Andreas Kapardis
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The paper discusses regulatory and legislative measures implemented by various nations in an effort to avert another financial crisis. More specifically, to address the financial crisis, the European Commission followed the practice of other developed countries and implemented a European Economic Recovery Plan in an attempt to overhaul the regulatory and supervisory framework of the financial sector. In 2010 the Commission introduced the European Systemic Risk Board and in 2011 the European System of Financial Supervision. Some experts advocated that the type and extent of financial regulation introduced in the European crisis in the wake of the 2008 crisis has been excessive and counterproductive. In considering how different countries responded to the financial crisis, global regulators have shown a more focused commitment to combat industry misconduct and to pre-empt abusive behavior. Regulators have also increased funding and resources at their disposal; have increased regulatory fines, with an increasing trend towards action against individuals; and, finally, have focused on market abuse and market conduct issues. Financial regulation can be effected, first of all, through legislation. However, neither ex ante or ex post regulation is by itself effective in reducing systemic risk. Consequently, to avert a financial crisis, in their endeavor to achieve both economic efficiency and financial stability, governments need to balance the two approaches to financial regulation. Fiduciary duty is another means by which the behavior of actors in the financial world is constrained and, thus, regulated. Furthermore, fiduciary duties extend over and above other existing requirements set out by statute and/or common law and cover allegations of breach of fiduciary duty, negligence or fraud. Careful analysis of the etiology of the 2008 financial crisis demonstrates the great importance of corporate governance as a way of regulating boardroom behavior. In addition, the regulation of professions including accountants and auditors plays a crucial role as far as the financial management of companies is concerned. In the US, the Sarbanes-Oxley Act of 2002 established the Public Company Accounting Oversight Board in order to protect investors from financial accounting fraud. In most countries around the world, however, accounting regulation consists of a legal framework, international standards, education, and licensure. Accounting regulation is necessary because of the information asymmetry and the conflict of interest that exists between managers and users of financial information. If a holistic approach is to be taken then one cannot ignore the regulation of legislators themselves which can take the form of hard or soft legislation. The science of averting a financial crisis is yet to be perfected and this, as shown by the preceding discussion, is unlikely to be achieved in the foreseeable future as ‘disaster myopia’ may be reduced but will not be eliminated. It is easier, of course, to be wise in hindsight and regulating unreasonably risky decisions and unethical or outright criminal behavior in the financial world remains major challenges for governments, corporations, and professions alike.Keywords: financial crisis, legislation, regulation, financial regulation
Procedia PDF Downloads 389265 Experimental and Simulation Results for the Removal of H2S from Biogas by Means of Sodium Hydroxide in Structured Packed Columns
Authors: Hamadi Cherif, Christophe Coquelet, Paolo Stringari, Denis Clodic, Laura Pellegrini, Stefania Moioli, Stefano Langè
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Biogas is a promising technology which can be used as a vehicle fuel, for heat and electricity production, or injected in the national gas grid. It is storable, transportable, not intermittent and substitutable for fossil fuels. This gas produced from the wastewater treatment by degradation of organic matter under anaerobic conditions is mainly composed of methane and carbon dioxide. To be used as a renewable fuel, biogas, whose energy comes only from methane, must be purified from carbon dioxide and other impurities such as water vapor, siloxanes and hydrogen sulfide. Purification of biogas for this application particularly requires the removal of hydrogen sulfide, which negatively affects the operation and viability of equipment especially pumps, heat exchangers and pipes, causing their corrosion. Several methods are available to eliminate hydrogen sulfide from biogas. Herein, reactive absorption in structured packed column by means of chemical absorption in aqueous sodium hydroxide solutions is considered. This study is based on simulations using Aspen Plus™ V8.0, and comparisons are done with data from an industrial pilot plant treating 85 Nm3/h of biogas which contains about 30 ppm of hydrogen sulfide. The rate-based model approach has been used for simulations in order to determine the efficiencies of separation for different operating conditions. To describe vapor-liquid equilibrium, a γ/ϕ approach has been considered: the Electrolyte NRTL model has been adopted to represent non-idealities in the liquid phase, while the Redlich-Kwong equation of state has been used for the vapor phase. In order to validate the thermodynamic model, Henry’s law constants of each compound in water have been verified against experimental data. Default values available in Aspen Plus™ V8.0 for the properties of pure components properties as heat capacity, density, viscosity and surface tension have also been verified. The obtained results for physical and chemical properties are in a good agreement with experimental data. Reactions involved in the process have been studied rigorously. Equilibrium constants for equilibrium reactions and the reaction rate constant for the kinetically controlled reaction between carbon dioxide and the hydroxide ion have been checked. Results of simulations of the pilot plant purification section show the influence of low temperatures, concentration of sodium hydroxide and hydrodynamic parameters on the selective absorption of hydrogen sulfide. These results show an acceptable degree of accuracy when compared with the experimental data obtained from the pilot plant. Results show also the great efficiency of sodium hydroxide for the removal of hydrogen sulfide. The content of this compound in the gas leaving the column is under 1 ppm.Keywords: biogas, hydrogen sulfide, reactive absorption, sodium hydroxide, structured packed column
Procedia PDF Downloads 343264 Islam in Nation Building: Case Studies of Kazakhstan and Kyrgyzstan
Authors: Etibar Guliyev, Durdana Jafarli
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The breakdown of the Soviet Union in the early 1990s and the 9/11 attacks resulted in the global changes created a totally new geopolitical situation for the Muslim populated republics of the former Soviet Union. Located between great powers such as China and Russia, as well as theocratic states like Iran and Afghanistan, the newly independent Central Asian states were facing a dilemma to choose a new politico-ideological course for development. Policies dubbed Perestroyka and Glasnost leading to the collapse of the world’s once superpower brought about a considerable rise in the national and religious self-consciousness of the Muslim population of the USSR where the religion was prohibited under the strict communist rule. Moreover, the religious movements prohibited during the Soviet era acted as a part of national straggle to gain their freedom from Moscow. The policies adopted by the Central Asian countries to manage the religious revival and extremism in their countries vary dramatically from each other. As Kazakhstan and Kyrgyzstan are located between Russia and China and hosting a considerable number of the Russian population, these countries treated Islamic revival more tolerantly trying benefit from it in the nation-building process. The importance of the topic could be explained with the fact that it investigates an alternative way of management of religious activities and movements. The recent developments in the Middle East, Syria and Iraq in particular, and the fact that hundreds of fighters from the Central Asian republics joined the ISIL terrorist organization once again highlights the implications of the proper regulation of religious activities not only for domestic, but also for regional and global politics. The paper is based on multiple research methods. The process trace method was exploited to better understand the Russification and anti-religious policies to which the Central Asian countries were subject during the Soviet era. The comparative analyse method was also used to better understand the common and distinct features of the politics of religion of Kazakhstan and Kyrgyzstan and the rest of the Central Asian countries. Various legislation acts, as well as secondary sources were investigated to this end. Mostly constructivist approach and a theory suggesting that religion supports national identity when there is a third cohesion that threatens both and when elements of national identity are weak. Preliminary findings suggest that in line with policies aimed at gradual reduction of Russian influence, as well as in the face of ever-increasing migration from China, the mentioned countries incorporated some Islamic elements into domestic policies as a part and parcel of national culture. Kazakhstan and Kyrgyzstan did not suppress religious activities, which was case in neighboring states, but allowed in a controlled way Islamic movements to have a relatively freedom of action which in turn led to the less violent religious extremism further boosting national identity.Keywords: identity, Islam, nationalism, terrorism
Procedia PDF Downloads 281263 A System for Preventing Inadvertent Exposition of Staff Present outside the Operating Theater: Description and Clinical Test
Authors: Aya Al Masri, Kamel Guerchouche, Youssef Laynaoui, Safoin Aktaou, Malorie Martin, Fouad Maaloul
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Introduction: Mobile C-arms move throughout operating rooms of the operating theater. Being designed to move between rooms, they are not equipped with relays to retrieve the exposition information and export it outside the room. Therefore, no light signaling is available outside the room to warn the X-ray emission for staff. Inadvertent exposition of staff outside the operating theater is a real problem for radiation protection. The French standard NFC 15-160 require that: (1) access to any room containing an X-ray emitting device must be controlled by a light signage so that it cannot be inadvertently crossed, and (2) setting up an emergency button to stop the X-ray emission. This study presents a system that we developed to meet these requirements and the results of its clinical test. Materials and methods: The system is composed of two communicating boxes: o The "DetectBox" is to be installed inside the operating theater. It identifies the various operation states of the C-arm by analyzing its power supply signal. The DetectBox communicates (in wireless mode) with the second box (AlertBox). o The "AlertBox" can operate in socket or battery mode and is to be installed outside the operating theater. It detects and reports the state of the C-arm by emitting a real time light signal. This latter can have three different colors: red when the C-arm is emitting X-rays, orange when it is powered on but does not emit X-rays, and green when it is powered off. The two boxes communicate on a radiofrequency link exclusively carried out in the ‘Industrial, Scientific and Medical (ISM)’ frequency bands and allows the coexistence of several on-site warning systems without communication conflicts (interference). Taking into account the complexity of performing electrical works in the operating theater (for reasons of hygiene and continuity of medical care), this system (having a size <10 cm²) works in complete safety without any intrusion in the mobile C-arm and does not require specific electrical installation work. The system is equipped with emergency button that stops X-ray emission. The system has been clinically tested. Results: The clinical test of the system shows that: it detects X-rays having both high and low energy (50 – 150 kVp), high and low photon flow (0.5 – 200 mA: even when emitted for a very short time (<1 ms)), Probability of false detection < 10-5, it operates under all acquisition modes (continuous, pulsed, fluoroscopy mode, image mode, subtraction and movie mode), it is compatible with all C-arm models and brands. We have also tested the communication between the two boxes (DetectBox and AlertBox) in several conditions: (1) Unleaded room, (2) leaded room, and (3) rooms with particular configuration (sas, great distances, concrete walls, 3 mm of lead). The result of these last tests was positive. Conclusion: This system is a reliable tool to alert the staff present outside the operating room for X-ray emission and insure their radiation protection.Keywords: Clinical test, Inadvertent staff exposition, Light signage, Operating theater
Procedia PDF Downloads 120262 An Appraisal of Blended Learning Approach for English Language Teaching in Saudi Arabia
Authors: H. Alqunayeer, S. Zamir
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Blended learning, an ideal amalgamation of online learning and face to face traditional approach is a new approach that may result in outstanding outcomes in the realm of teaching and learning. The dexterity and effectiveness offered by e-learning experience cannot be guaranteed in a traditional classroom, whereas one-to-one interaction the essential element of learning that can only be found in a traditional classroom. In recent years, a spectacular expansion in the incorporation of technology in language teaching and learning is observed in many universities of Saudi Arabia. Some universities recognize the importance of blending face-to-face with online instruction in language pedagogy, Qassim University is one of the many universities adopting Blackboard Learning Management system (LMS). The university has adopted this new mode of teaching/learning in year 2015. Although the experience is immature; however great pedagogical transformations are anticipated in the university through this new approach. This paper examines the role of blended language learning with particular reference to the influence of Blackboard Learning Management System on the development of English language learning for EFL learners registered in Bachelors of English language program. This paper aims at exploring three main areas: (i) the present status of Blended learning in the educational process in Saudi Arabia especially in Qassim University by providing a survey report on the number of training courses on Blackboard LMS conducted for the male and female teachers at various colleges of Qassim University, (ii) a survey on teachers perception about the utility, application and the outcome of using blended Learning approach in teaching English language skills courses, (iii) the students’ views on the efficiency of Blended learning approach in learning English language skills courses. Besides, analysis of students’ limitations and challenges related to the experience of blended learning via Blackboard, the suggestion and recommendations offered by the language learners have also been thought-out. The study is empirical in nature. In order to gather data on the afore mentioned areas survey questionnaire method has been used: in order to study students’ perception, a 5 point Likert-scale questionnaire has been distributed to 200 students of English department registered in Bachelors in English program (level 5 through level 8). Teachers’ views have been surveyed with the help of interviewing 25 EFL teachers skilled in using Blackboard LMS in their lectures. In order to ensure the validity and reliability of questionnaire, the inter-rater approach and Cronbach’s Alpha analysis have been used respectively. Analysis of variance (ANOVA) has been used to analyze the students’ perception about the productivity of the Blended approach in learning English language skills. The analysis of feedback by Saudi teachers and students about the usefulness, ingenuity, and productivity of Blended Learning via Blackboard LMS highlights the need of encouraging and expanding the implementation of this new approach into the field of English language teaching in Saudi Arabia, in order to augment congenial learning aura. Furthermore, it is hoped that the propositions and practical suggestions offered by the study will be functional for other similar learning environments.Keywords: blended learning, black board learning management system, English as foreign language (EFL) learners, EFL teachers
Procedia PDF Downloads 150261 A Novel Nanocomposite Membrane Designed for the Treatment of Oil/Gas Produced Water
Authors: Zhaoyang Liu, Detao Qin, Darren Delai Sun
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The onshore production of oil and gas (for example, shale gas) generates large quantities of wastewater, referred to be ‘produced water’, which contains high contents of oils and salts. The direct discharge of produced water, if not appropriately treated, can be toxic to the environment and human health. Membrane filtration has been deemed as an environmental-friendly and cost-effective technology for treating oily wastewater. However, conventional polymeric membranes have their drawbacks of either low salt rejection rate or high membrane fouling tendency when treating oily wastewater. Recent years, forward osmosis (FO) membrane filtration has emerged as a promising technology with its unique advantages of low operation pressure and less membrane fouling tendency. However, until now there is still no report about FO membranes specially designed and fabricated for treating the oily and salty produced water. In this study, a novel nanocomposite FO membrane was developed specially for treating oil- and salt-polluted produced water. By leveraging the recent advance of nanomaterials and nanotechnology, this nanocomposite FO membrane was designed to be made of double layers: an underwater oleophobic selective layer on top of a nanomaterial infused polymeric support layer. Wherein, graphene oxide (GO) nanosheets were selected to add into the polymeric support layer because adding GO nanosheets can optimize the pore structures of the support layer, thus potentially leading to high water flux for FO membranes. In addition, polyvinyl alcohol (PVA) hydrogel was selected as the selective layer because hydrated and chemically-crosslinked PVA hydrogel is capable of simultaneously rejecting oil and salt. After nanocomposite FO membranes were fabricated, the membrane structures were systematically characterized with the instruments of TEM, FESEM, XRD, ATR-FTIR, surface zeta-potential and Contact angles (CA). The membrane performances for treating produced waters were tested with the instruments of TOC, COD and Ion chromatography. The working mechanism of this new membrane was also analyzed. Very promising experimental results have been obtained. The incorporation of GO nanosheets can reduce internal concentration polarization (ICP) effect in the polymeric support layer. The structural parameter (S value) of the new FO membrane is reduced by 23% from 265 ± 31 μm to 205 ± 23 μm. The membrane tortuosity (τ value) is decreased by 20% from 2.55 ± 0.19 to 2.02 ± 0.13 μm, which contributes to the decrease of S value. Moreover, the highly-hydrophilic and chemically-cross-linked hydrogel selective layer present high antifouling property under saline oil/water emulsions. Compared with commercial FO membrane, this new FO membrane possesses three times higher water flux, higher removal efficiencies for oil (>99.9%) and salts (>99.7% for multivalent ions), and significantly lower membrane fouling tendency (<10%). To our knowledge, this is the first report of a nanocomposite FO membrane with the combined merits of high salt rejection, high oil repellency and high water flux for treating onshore oil/gas produced waters. Due to its outstanding performance and ease of fabrication, this novel nanocomposite FO membrane possesses great application potential in wastewater treatment industry.Keywords: nanocomposite, membrane, polymer, graphene oxide
Procedia PDF Downloads 245260 Relative Expression and Detection of MUB Adhesion Domains and Plantaricin-Like Bacteriocin among Probiotic Lactobacillus plantarum-Group Strains Isolated from Fermented Foods
Authors: Sundru Manjulata Devi, Prakash M. Halami
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The immemorial use of fermented foods from vegetables, dairy and other biological sources are of great demand in India because of their health benefits. However, the diversity of Lactobacillus plantarum group (LPG) of vegetable origin has not been revealed yet, particularly with reference to their probiotic functionalities. In the present study, the different species of probiotic Lactobacillus plantarum group (LPG) i.e., L. plantarum subsp. plantarum MTCC 5422 (from fermented cereals), L. plantarum subsp. argentoratensis FG16 (from fermented bamboo shoot) and L. paraplantarum MTCC 9483 (from fermented gundruk) (as characterized by multiplex recA PCR assay) were considered to investigate their relative expression of MUB domains of mub gene (mucin binding protein) by Real time PCR. Initially, the allelic variation in the mub gene was assessed and found to encode three different variants (Type I, II and III). All the three types had 8, 9 and 10 MUB domains respectively (as analysed by Pfam database) and were found to be responsible for adhesion of bacteria to the host intestinal epithelial cells. These domains either get inserted or deleted during speciation or evolutionary events and lead to divergence. The reverse transcriptase qPCR analysis with mubLPF1+R1 primer pair supported variation in amplicon sizes with 300, 500 and 700 bp among different LPG strains. The relative expression of these MUB domains significantly unregulated in the presence of 1% mucin in overnight grown cultures. Simultaneously, the mub gene expressed efficiently by 7 fold in the culture L. paraplantarum MTCC 9483 with 10 MUB domains. An increase in the expression levels for L. plantarum subsp. plantarum MTCC 5422 and L. plantarum subsp. argentoratensis FG16 (MCC 2974) with 9 and 8 repetitive domains was around 4 and 2 fold, respectively. The detection and expression of an integrase (int) gene in the upstream region of mub gene reveals the excision and integration of these repetitive domains. Concurrently, an in vitro adhesion assay to mucin and exclusion of pathogens (such as Listeria monocytogenes and Micrococcus leuteus) was investigated and observed that the L. paraplantarum MTCC 9483 with more adhesion domains has more ability to adhere to mucin and inhibited the growth of pathogens. The production and expression of plantaricin-like bacteriocin (plnNC8 type) in MTCC 9483 suggests the pathogen inhibition. Hence, the expression of MUB domains can act as potential biomarkers in the screening of a novel probiotic LPG strain with adherence property. The present study provides a platform for an easy, rapid, less time consuming, low-cost methodology for the detection of potential probiotic bacteria. It was known that the traditional practices followed in the preparation of fermented bamboo shoots/gundruk/cereals of Indian foods contain different kinds of neutraceuticals for functional food and novel compounds with health promoting factors. In future, a detailed study of these food products can add more nutritive value, consumption and suitable for commercialization.Keywords: adhesion gene, fermented foods, MUB domains, probiotics
Procedia PDF Downloads 265259 Effect of Ion Irradiation on the Microstructure and Properties of Chromium Coatings on Zircaloy-4 Substrate
Authors: Alexia Wu, Joel Ribis, Jean-Christophe Brachet, Emmanuel Clouet, Benoit Arnal, Elodie Rouesne, Stéphane Urvoy, Justine Roubaud, Yves Serruys, Frederic Lepretre
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To enhance the safety of Light Water Reactor, accident tolerant fuel (ATF) claddings materials are under development. In the framework of CEA-AREVA-EDF collaborative program on ATF cladding materials, CEA has engaged specific studies on chromium coated zirconium alloys. Especially for Loss-of-Coolant-Accident situations, chromium coated claddings have shown some additional 'coping' time before achieving full embrittlement of the oxidized cladding, when compared to uncoated references – both tested in steam environment up to 1300°C. Nevertheless, the behavior of chromium coatings and the stability of the Zr-Cr interface under neutron irradiation remain unknown. Two main points are addressed: 1. Bulk Cr behavior under irradiation: Due to its BCC crystallographic structure, Cr is prone to Ductile-to-Brittle-Transition at quite high temperature. Irradiation could be responsible for a significant additional DBTT shift towards higher temperatures. 2. Zircaloy/Cr interface behavior under irradiation: Preliminary TEM examinations of un-irradiated samples revealed a singular Zircaloy-4/Cr interface with nanometric intermetallic phase layers. Such particular interfaces highlight questions of how they would behave under irradiation - intermetallic zirconium phases are known to be more or less stable under irradiations. Another concern is a potential enhancement of chromium diffusion into the zirconium-alpha based substrate. The purpose of this study is then to determine the behavior of such coatings after ion irradiations, as a surrogate to neutron irradiation. Ion irradiations were performed at the Jannus-Saclay facility (France). 20 MeV Kr8+ ions at 400°C with a flux of 2.8x1011 ions.cm-2.s-1 were used to irradiate chromium coatings of 1-2 µm thick on Zircaloy-4 sheets substrate. At the interface, the calculated damage is close to 10 dpa (SRIM, Quick Calculation Damage mode). Thin foil samples were prepared with FIB for both as-received and irradiated coated samples. Transmission Electron Microscopy (TEM) and in-situ tensile tests in a Scanning Electron Microscope are being used to characterize the un-irradiated and irradiated materials. High Resolution TEM highlights a great complexity of the interface before irradiation since it is formed of an alternation of intermetallic phases – C14 and C15. The interfaces formed by these intermetallic phases with chromium and zirconium show semi-coherency. Chemical analysis performed before irradiation shows some iron enrichment at the interface. The chromium coating bulk microstructures and properties are also studied before and after irradiation. On-going in-situ tensile tests focus on the capacity of chromium coatings to sustain some plastic deformation when tested up to 350°C. The stability of the Cr/Zr interface is shown after ion irradiation up to 10 dpa. This observation constitutes the first result after irradiation on these new coated claddings materials.Keywords: accident tolerant fuel, HRTEM, interface, ion-irradiation
Procedia PDF Downloads 357258 Prognostic Factors for Mortality and Duration of Admission in Malnourished Hospitalized, Elderly Patients: A Cross-Sectional Study
Authors: Christos E. Lampropoulos, Maria Konsta, Vicky Dradaki, Irini Dri, Tamta Sirbilatze, Ifigenia Apostolou, Christina Kordali, Konstantina Panouria, Kostas Argyros, Georgios Mavras
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Malnutrition in hospitalized patients is related to increased morbidity and mortality. Purpose of our study was to assess nutritional status of hospitalized, elderly patients with various nutritional scores and to detect unfavorable prognostic factors, related to increased mortality and extended duration of admission. Methods: 150 patients (78 men, 72 women, mean age 80±8.2) were included in this cross-sectional study. Nutritional status was assessed by Mini Nutritional Assessment (MNA full, short-form), Malnutrition Universal Screening Tool (MUST) and short Nutritional Appetite Questionnaire (sNAQ). The following data were incorporated in analysis: Anthropometric and laboratory data, physical activity (International Physical Activity Questionnaires, IPAQ), smoking status, dietary habits and mediterranean diet (assessed by MedDiet score), cause and duration of current admission, medical history (co-morbidities, previous admissions). Primary endpoints were the mortality (from admission until 6 months afterwards) and duration of admission, compared to national guidelines for closed consolidated medical expenses. Mann-Whitney two-sample statistics or t-test was used for group comparisons and Spearman or Pearson coefficients for testing correlation between variables. Results: Normal nutrition was assessed in 54/150 (36%), 92/150 (61.3%) and in 106/150 (70.7%) of patients, according to full MNA, MUST and sNAQ questionnaires respectively. Mortality rate was 20.7% (31/150 patients). The patients who died until 6 months after admission had lower BMI (24±4.4 vs 26±4.8, p=0.04) and albumin levels (2.9±0.7 vs 3.4±0.7, p=0.002), significantly lower full MNA (14.5±7.3 vs 20.7±6, p<0.0001) and short-form MNA scores (7.3±4.2 vs 10.5±3.4, p=0.0002) compared to non-dead one. In contrast, the aforementioned patients had higher MUST (2.5±1.8 vs 0.5±1.02, p=<0.0001) and sNAQ scores (2.9±2.4 vs 1.1±1.3, p<0.0001). Additionally, they showed significantly lower MedDiet (23.5±4.3 vs 31.1±5.6, p<0.0001) and IPAQ scores (37.2±156.2 vs 516.5±1241.7, p<0.0001) compared to remaining one. These patients had extended hospitalization [5 (0-13) days vs 0 (-1-3) days, p=0.001]. Patients who admitted due to cancer depicted higher mortality rate (10/13, 77%), compared to those who admitted due to infections (12/73, 18%), stroke (4/15, 27%) or other causes (4/49, 8%) (p<0.0001). Extension of hospitalization was negatively correlated to both full (Spearman r=-0.35, p<0.0001) and short-form MNA (Spearman r=-0.33, p<0.0001) and positively correlated to MUST (Spearman r=0.34, p<0.0001) and sNAQ (Spearman r=0.3, p=0.0002). Additionally, the extension was inversely related to MedDiet score (Spearman r=-0.35, p<0.0001), IPAQ score (Spearman r=-0.34, p<0.0001), albumin levels (Pearson r=-0.36, p<0.0001), Ht (Pearson r=-0.2, p=0.02) and Hb (Pearson r=-0.18, p=0.02). Conclusion: A great proportion of elderly, hospitalized patients are malnourished or at risk of malnutrition. All nutritional scores, physical activity and albumin are significantly related to mortality and increased hospitalization.Keywords: dietary habits, duration of admission, malnutrition, prognostic factors for mortality
Procedia PDF Downloads 282257 Work Related Outcomes of Perceived Authentic Leadership: Moderating Role of Organizational Structures
Authors: Aisha Zubair, Anila Kamal
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Leadership styles and practices greatly influence the organizational effectiveness and productivity. It also plays an important role in employees’ experiences of positive emotions at workplace and creative work behaviors. Authentic leadership as a newly emerging concept has been found as a significant predictor of various desirable work related outcomes. However, leadership practices and its work related outcomes, to a great extent, are determined by the very nature of the organizational structures (tall and flat). Tall organizations are characterized by multiple hierarchical layers with predominant vertical communication patterns, and narrow span of control; while flat organizations are featured by few layers of management employing both horizontal and vertical communication styles, and wide span of control. Therefore, the present study was undertaken to determine the work related outcomes of perceived authentic leadership; that is work related flow and creative work behavior among employees of flat and tall organizations. Moreover, it was also intended to determine the moderating role of organizational structure (flat and tall) in the relationship between perceived authentic leadership with work related flow and creative work behavior. In this regard, two types of companies have been considered; that is, banks as a form of tall organizational structure with multiple hierarchical structures while software companies have been considered as flat organizations with minimal layers of management. Respondents (N = 1180) were full time regular employees of marketing departments of banks (600) and software companies (580) including both men and women with age range of 22-52 years (M = 33.24; SD = 7.81). Confirmatory Factor Analysis yielded factor structures of measures of work related flow and creative work behavior in accordance to the theoretical models. However, model of authentic leadership exhibited variation in terms of two items which were not included in the final measure of the perceived authentic leadership. Results showed that perceived authentic leadership was positively associated with work related flow and creative work behavior. Likewise, work related flow was positively aligned with creative work behavior. Furthermore, type of organizational structure significantly moderated the relationship of perceived authentic leadership with work related flow and creative work behavior. Results of independent sample t-test showed that employees working in flat organization reflected better perceptions of authentic leadership; higher work related flow and elevated levels of creative work behavior as compared to those working in tall organizations. It was also found that employees with extended job experience and more job duration in the same organization displayed better perceptions of authentic leadership, reported more work related flow and augmented levels of creative work behavior. Findings of the present study distinctively highlighted the similarities as well as differences in the interactions of major constructs which function differentially in the context of tall (banks) and flat (software companies) organizations. Implications of the present study for employees and management as well as future recommendations were also discussed.Keywords: creative work behavior, organizational structure, perceived authentic leadership, work related flow
Procedia PDF Downloads 384256 Comparative Appraisal of Polymeric Matrices Synthesis and Characterization Based on Maleic versus Itaconic Anhydride and 3,9-Divinyl-2,4,8,10-Tetraoxaspiro[5.5]-Undecane
Authors: Iordana Neamtu, Aurica P. Chiriac, Loredana E. Nita, Mihai Asandulesa, Elena Butnaru, Nita Tudorachi, Alina Diaconu
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In the last decade, the attention of many researchers is focused on the synthesis of innovative “intelligent” copolymer structures with great potential for different uses. This considerable scientific interest is stimulated by possibility of the significant improvements in physical, mechanical, thermal and other important specific properties of these materials. Functionalization of polymer in synthesis by designing a suitable composition with the desired properties and applications is recognized as a valuable tool. In this work is presented a comparative study of the properties of the new copolymers poly(maleic anhydride maleic-co-3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]undecane) and poly(itaconic-anhydride-co-3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]undecane) obtained by radical polymerization in dioxane, using 2,2′-azobis(2-methylpropionitrile) as free-radical initiator. The comonomers are able for generating special effects as for example network formation, biodegradability and biocompatibility, gel formation capacity, binding properties, amphiphilicity, good oxidative and thermal stability, good film formers, and temperature and pH sensitivity. Maleic anhydride (MA) and also the isostructural analog itaconic anhydride (ITA) as polyfunctional monomers are widely used in the synthesis of reactive macromolecules with linear, hyperbranched and self & assembled structures to prepare high performance engineering, bioengineering and nano engineering materials. The incorporation of spiroacetal groups in polymer structures improves the solubility and the adhesive properties, induce good oxidative and thermal stability, are formers of good fiber or films with good flexibility and tensile strength. Also, the spiroacetal rings induce interactions on ether oxygen such as hydrogen bonds or coordinate bonds with other functional groups determining bulkiness and stiffness. The synthesized copolymers are analyzed by DSC, oscillatory and rotational rheological measurements and dielectric spectroscopy with the aim of underlying the heating behavior, solution viscosity as a function of shear rate and temperature and to investigate the relaxation processes and the motion of functional groups present in side chain around the main chain or bonds of the side chain. Acknowledgments This work was financially supported by the grant of the Romanian National Authority for Scientific Research, CNCS-UEFISCDI, project number PN-II-132/2014 “Magnetic biomimetic supports as alternative strategy for bone tissue engineering and repair’’ (MAGBIOTISS).Keywords: Poly(maleic anhydride-co-3, 9-divinyl-2, 4, 8, 10-tetraoxaspiro (5.5)undecane); Poly(itaconic anhydride-co-3, 9-divinyl-2, 4, 8, 10-tetraoxaspiro (5.5)undecane); DSC; oscillatory and rotational rheological analysis; dielectric spectroscopy
Procedia PDF Downloads 223255 Assessment of Heavy Metals Contamination Levels in Groundwater: A Case Study of the Bafia Agricultural Area, Centre Region Cameroon
Authors: Carine Enow-Ayor Tarkang, Victorine Neh Akenji, Dmitri Rouwet, Jodephine Njdma, Andrew Ako Ako, Franco Tassi, Jules Remy Ngoupayou Ndam
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Groundwater is the major water resource in the whole of Bafia used for drinking, domestic, poultry and agricultural purposes, and being an area of intense agriculture, there is a great necessity to do a quality assessment. Bafia is one of the main food suppliers in the Centre region of Cameroon, and so to meet their demands, the farmers make use of fertilizers and other agrochemicals to increase their yield. Less than 20% of the population in Bafia has access to piped-borne water due to the national shortage, according to the authors best knowledge very limited studies have been carried out in the area to increase awareness of the groundwater resources. The aim of this study was to assess heavy metal contamination levels in ground and surface waters and to evaluate the effects of agricultural inputs on water quality in the Bafia area. 57 water samples (including 31 wells, 20 boreholes, 4 rivers and 2 springs) were analyzed for their physicochemical parameters, while collected samples were filtered, acidified with HNO3 and analyzed by ICP-MS for their heavy metal content (Fe, Ti, Sr, Al, Mn). Results showed that most of the water samples are acidic to slightly neutral and moderately mineralized. Ti concentration was significantly high in the area (mean value 130µg/L), suggesting another Ti source besides the natural input from Titanium oxides. The high amounts of Mn and Al in some cases also pointed to additional input, probably from fertilizers that are used in the farmlands. Most of the water samples were found to be significantly contaminated with heavy metals exceeding the WHO allowable limits (Ti-94.7%, Al-19.3%, Mn-14%, Fe-5.2% and Sr-3.5% above limits), especially around farmlands and topographic low areas. The heavy metal concentration was evaluated using the heavy metal pollution index (HPI), heavy metal evaluation index (HEI) and degree of contamination (Cd), while the Ficklin diagram was used for the water based on changes in metal content and pH. The high mean values of HPI and Cd (741 and 5, respectively), which exceeded the critical limit, indicate that the water samples are highly contaminated, with intense pollution from Ti, Al and Mn. Based on the HPI and Cd, 93% and 35% of the samples, respectively, are unacceptable for drinking purposes. The lowest HPI value point also had the lowest EC (50 µS/cm), indicating lower mineralization and less anthropogenic influence. According to the Ficklin diagram, 89% of the samples fell within the near-neutral low-metal domain, while 9% fell in the near-neutral extreme-metal domain. Two significant factors were extracted from the PCA, explaining 70.6% of the total variance. The first factor revealed intense anthropogenic activity (especially from fertilizers), while the second factor revealed water-rock interactions. Agricultural activities thus have an impact on the heavy metal content of groundwater in the area; hence, much attention should be given to the affected areas in order to protect human health/life and thus sustainably manage this precious resource.Keywords: Bafia, contamination, degree of contamination, groundwater, heavy metal pollution index
Procedia PDF Downloads 75254 Green Production of Chitosan Nanoparticles and their Potential as Antimicrobial Agents
Authors: L. P. Gomes, G. F. Araújo, Y. M. L. Cordeiro, C. T. Andrade, E. M. Del Aguila, V. M. F. Paschoalin
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The application of nanoscale materials and nanostructures is an emerging area, these since materials may provide solutions to technological and environmental challenges in order to preserve the environment and natural resources. To reach this goal, the increasing demand must be accompanied by 'green' synthesis methods. Chitosan is a natural, nontoxic, biopolymer derived by the deacetylation of chitin and has great potential for a wide range of applications in the biological and biomedical areas, due to its biodegradability, biocompatibility, non-toxicity and versatile chemical and physical properties. Chitosan also presents high antimicrobial activities against a wide variety of pathogenic and spoilage microorganisms. Ultrasonication is a common tool for the preparation and processing of polymer nanoparticles. It is particularly effective in breaking up aggregates and in reducing the size and polydispersity of nanoparticles. High-intensity ultrasonication has the potential to modify chitosan molecular weight and, thus, alter or improve chitosan functional properties. The aim of this study was to evaluate the influence of sonication intensity and time on the changes of commercial chitosan characteristics, such as molecular weight and its potential antibacterial activity against Gram-negative bacteria. The nanoparticles (NPs) were produced from two commercial chitosans, of medium molecular weight (CS-MMW) and low molecular weight (CS-LMW) from Sigma-Aldrich®. These samples (2%) were solubilized in 100 mM sodium acetate pH 4.0, placed on ice and irradiated with an ultrasound SONIC ultrasonic probe (model 750 W), equipped with a 1/2" microtip during 30 min at 4°C. It was used on constant duty cycle and 40% amplitude with 1/1s intervals. The ultrasonic degradation of CS-MMW and CS-LMW were followed up by means of ζ-potential (Brookhaven Instruments, model 90Plus) and dynamic light scattering (DLS) measurements. After sonication, the concentrated samples were diluted 100 times and placed in fluorescence quartz cuvettes (Hellma 111-QS, 10 mm light path). The distributions of the colloidal particles were calculated from the DLS and ζ-potential are measurements taken for the CS-MMW and CS-LMW solutions before and after (CS-MMW30 and CS-LMW30) sonication for 30 min. Regarding the results for the chitosan sample, the major bands can be distinguished centered at Radius hydrodynamic (Rh), showed different distributions for CS-MMW (Rh=690.0 nm, ζ=26.52±2.4), CS-LMW (Rh=607.4 and 2805.4 nm, ζ=24.51±1.29), CS-MMW30 (Rh=201.5 and 1064.1 nm, ζ=24.78±2.4) and CS-LMW30 (Rh=492.5, ζ=26.12±0.85). The minimal inhibitory concentration (MIC) was determined using different chitosan samples concentrations. MIC values were determined against to E. coli (106 cells) harvested from an LB medium (Luria-Bertani BD™) after 18h growth at 37 ºC. Subsequently, the cell suspension was serially diluted in saline solution (0.8% NaCl) and plated on solid LB at 37°C for 18 h. Colony-forming units were counted. The samples showed different MICs against E. coli for CS-LMW (1.5mg), CS-MMW30 (1.5 mg/mL) and CS-LMW30 (1.0 mg/mL). The results demonstrate that the production of nanoparticles by modification of their molecular weight by ultrasonication is simple to be performed and dispense acid solvent addition. Molecular weight modifications are enough to provoke changes in the antimicrobial potential of the nanoparticles produced in this way.Keywords: antimicrobial agent, chitosan, green production, nanoparticles
Procedia PDF Downloads 319253 Country Experience on Regulation of Traditional Medicine in Eritrea
Authors: Liya Abraham
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Eritrea is located along the Red Sea, north of the Horn of Africa, between Djibouti and Sudan and has a population of about 3.2 million as of 2010. It has six administrative regions; Anseba, Debub, Debubawi K’eyih Bahri, Gash-Barka, Ma'akel, and Semenawi K’eyih Bahri. Eritrea has got its independence in 1991 after 30 years war of liberation. The country is blessed with various medicinal flora and fauna, and marine and terrestrial biodiversity. Traditional Medicine (TM) has been an integral part of the Eritrean culture for centuries. So far, more than 19 TM modalities have been recognized, and are broadly categorized as; herbal, procedure-based and spiritual. Despite the availability of modern medicine to the majority of the population, TM is still widely practiced. The rationale behind widespread use is accessibility, affordability and cultural acceptability. Hence, TM is of great contribution to the Eritrean health care system. As a matter of fact, harnessing the potential contribution of effective and safe TM in order to attain Universal Health Coverage (UHC) has been emphasized in the WHO TM strategy 2014-2023. The Eritrean TM, however, was operating without regulation and reliable scientific justification behind its safety and efficacy. Thus, the Ministry of Health (MoH), in recognition of the role of TM in primary healthcare and safeguard public health, established a regulatory body for TM so-called as Traditional Medicine Unit (TMU) in 2012. The mission of the unit is to ensure rational TM use through an integrated health service delivery system and contribute to the country’s economic and social development. The unit has established its national TM policy in 2017. The activities of the unit are guided by the National TM Advisory Committee (TMAC), responsible for the provision of technical assistance and advisory role. Moreover, the Legal Framework and Code of Ethics and Practice which provide a legal basis for the regulation of TM have also been drafted. In recognition of the importance of TM research and development, the unit launched a nationwide TM survey in 2017 and had surveyed two zones (Gash-Barka and Debub). The findings of the survey were subjected to a research dissemination workshop and publication in international journals. Furthermore, TM-related adverse events reporting tool (Green Form) aiming to guide regulatory interventions and researches have been established by the unit, and ever since reports are flowing. The unit has also been offering training to THPs, pharmacy students and health care professionals regarding TM and its regulatory activities. In addition, as part of the establishment of the national medicinal plants' database and herbal monograph, more than 329 and 30 medicinal plants, have been compiled respectively. In conclusion, TM is still widely accepted and practiced in Eritrea. The TMU ever since its establishment is endeavoring to ensure the safety and efficacy of the TM, and its integration in the mainstream health service delivery system.Keywords: efficacy, regulation, safety, traditional medicine, traditional medicine unit, universal health coverage
Procedia PDF Downloads 175252 Analysis of the Potential of Biomass Residues for Energy Production and Applications in New Materials
Authors: Sibele A. F. Leite, Bernno S. Leite, José Vicente H. D´Angelo, Ana Teresa P. Dell’Isola, Julio CéSar Souza
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The generation of bioenergy is one of the oldest and simplest biomass applications and is one of the safest options for minimizing emissions of greenhouse gasses and replace the use of fossil fuels. In addition, the increasing development of technologies for energy biomass conversion parallel to the advancement of research in biotechnology and engineering has enabled new opportunities for exploitation of biomass. Agricultural residues offer great potential for energy use, and Brazil is in a prominent position in the production and export of agricultural products such as banana and rice. Despite the economic importance of the growth prospects of these activities and the increasing of the agricultural waste, they are rarely explored for energy and production of new materials. Brazil products almost 10.5 million tons/year of rice husk and 26.8 million tons/year of banana stem. Thereby, the aim of this study was to analysis the potential of biomass residues for energy production and applications in new materials. Rice husk (specify the type) and banana stem (specify the type) were characterized by physicochemical analyses using the following parameters: organic carbon, nitrogen (NTK), proximate analyses, FT-IR spectroscopy, thermogravimetric analyses (TG), calorific values and silica content. Rice husk and banana stem presented attractive superior calorific (from 11.5 to 13.7MJ/kg), and they may be compared to vegetal coal (21.25 MJ/kg). These results are due to the high organic matter content. According to the proximate analysis, biomass has high carbon content (fixed and volatile) and low moisture and ash content. In addition, data obtained by Walkley–Black method point out that most of the carbon present in the rice husk (50.5 wt%) and in banana stalk (35.5 wt%) should be understood as organic carbon (readily oxidizable). Organic matter was also detected by Kjeldahl method which gives the values of nitrogen (especially on the organic form) for both residues: 3.8 and 4.7 g/kg of rice husk and banana stem respectively. TG and DSC analyses support the previous results, as they can provide information about the thermal stability of the samples allowing a correlation between thermal behavior and chemical composition. According to the thermogravimetric curves, there were two main stages of mass-losses. The first and smaller one occurred below 100 °C, which was suitable for water losses and the second event occurred between 200 and 500 °C which indicates decomposition of the organic matter. At this broad peak, the main loss was between 250-350 °C, and it is because of sugar decomposition (components readily oxidizable). Above 350 °C, mass loss of the biomass may be associated with lignin decomposition. Spectroscopic characterization just provided qualitative information about the organic matter, but spectra have shown absorption bands around 1030 cm-1 which may be identified as species containing silicon. This result is expected for the rice husk and deserves further investigation to the stalk of banana, as it can bring a different perspective for this biomass residue.Keywords: rice husk, banana stem, bioenergy, renewable feedstock
Procedia PDF Downloads 273251 Investigations at the Settlement of Oglankala
Authors: Ayten Tahirli
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Settlements and grave monuments discovered by archeological excavations conducted in Nakhchivan Autonomous Republic have a special place in studying the Ancient history of Azerbaijan between the 4th century B.C. and the 3rd century A.C. From this point of view, the archeological excavations and investigations conducted at Oglankala, Goshatapa, Babatapa, Pusyan, Agvantapa, Meydantapa and other monuments in Nakhchivan have a specific place. From this point of view, the conclusions of archeological research conducted at the Oglankala settlement enable studying of Nakhchivan history, economic life and trade relationships broadly. Oglankala, which is located on Garatapa Mountain with a space of 50 ha, was the largest fortress in Nakhchivan and one of the largest fortresses in the South Caucasus during the Middle Iron Age. The territory where the monument is located is very important in terms of keeping Sharur Lowland, which has great importance for agriculture and is the most productive territory in Nakhchivan, where Arpachay passes starting from the Lesser Caucasus. During the excavations between 1988 and 1989 at Oglankala, covering the fortress's history belonging to the Early and Middle Iron Ages, indisputable proofs showing that the territory was an important political center were discovered at that territory. Oglankala was the capital city of an independent government during the Middle Iron Age. It maintained economic and cultural relationships with the neighboring Urartu Government and was the capital city of a city government covered by a strong protection system in the centuries after the collapse of the Achaemenid Empire. It is need say that broader archeological excavations at Oglankala City were first started by Vali Bakhshaliyev, the Department Head of the Institute of History, Ethnography and Archeology of ANAS Nakhchivan Branch. Between 1988 and 1989, V.B. Bakhshaliyev conducted an excavation within an area of 320 square meters at Oglankala. Since 2006, Oglankala has become a research object for the International Azerbaijan-USA archeological expedition. In 2006, Lauren Ristvet from Pennsylvania State University, Veli Bakhshaliyev from the Nakhchivan Branch of Azerbaijan National Academy of Sciences and Safar Ashurov from Baku Office of Azerbaijan National Academy of Sciences, together with their other colleagues and students, started to study the ancient history of that magic area. During the archeological research conducted by an international expedition between 2008 and 2011 under the supervision of Vali Bakhshaliyev, the remnants of a palace and the protective walls of a citadel constructed between late 9th century B.C. and early 8th century A.C. were discovered in that residential area. It was found out that Oglankala was the capital city of a small government established at Sharur Lowland during the Middle Iron Age and struggled against the Urartu by establishing a union with the local tribes. That government had a specific cuneiform script. Between the 4th and 2nd centuries B.C., Oglankala and the territory it covered was one of the major political centers of the Atropathena Government.Keywords: Nakhchivan, Oglankala, settlement, ceramic, archaeological excavation
Procedia PDF Downloads 72250 Development of Metal-Organic Frameworks-Type Hybrid Functionalized Materials for Selective Uranium Extraction
Authors: Damien Rinsant, Eugen Andreiadis, Michael Carboni, Daniel Meyer
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Different types of materials have been developed for the solid/liquid uranium extraction processes, such as functionalized organic polymers, hybrid silica or inorganic adsorbents. In general, these materials exhibit a moderate affinity for uranyl ions and poor selectivity against impurities like iron, vanadium or molybdenum. Moreover, the structural organization deficiency of these materials generates ion diffusion issues inside the material. Therefore, the aim of our study is to developed efficient and organized materials, stable in the acid media encountered in uranium extraction processes. Metal organic frameworks (MOFs) are hybrid crystalline materials consisting of an inorganic part (cluster or metal ions) and tailored organic linkers connected via coordination bonds. These hierarchical materials have exceptional surface area, thermal stability and a large variety of tunable structures. However, due to the reversibility of constitutive coordination bonds, MOFs have moderate stability in strongly complexing or acidic media. Only few of them are known to be stable in aqueous media and only one example is described in strong acidic media. However, these conditions are very often encountered in the environmental pollution remediation of mine wastewaters. To tackle the challenge of developing MOFs adapted for uranium extraction from acid mine waters, we have investigated the stability of several materials. To ensure a good stability we have synthetized and characterized different materials based on highly coordinated metal clusters, such as LnOFs and Zirconium based materials. Among the latter, the UiO family shows a great stability in sulfuric acid media even in the presence of 1.4 M sodium sulfate at pH 2. However, the stability in phosphoric media is reduced due to the high affinity between zirconium and phosphate ligand. Based on these results, we have developed a tertiary amine functionalized MOF denoted UiO-68-NMe2 particularly adapted for the extraction of anionic uranyl (VI) sulfate complexes mainly present in the acid mine solutions. The adsorption capacity of the material has been determined upon varying total sulfate concentration, contact time and uranium concentration. The extraction tests put in evidence different phenomena due to the complexity of the extraction media and the interaction between the MOF and sulfate anion. Finally, the extraction mechanisms and the interaction between uranyl and the MOF structure have been investigated. The functionalized material UiO-68-NMe2 has been characterized in the presence and absence of uranium by FT-IR, UV and Raman techniques. Moreover, the stability of the protonated amino functionalized MOF has been evaluated. The synthesis, characterization and evaluation of this type of hybrid material, particularly adapted for uranium extraction in sulfuric acid media by an anionic exchange mechanism, paved the way for the development of metal organic frameworks functionalized by different other chelating motifs, such as bifunctional ligands showing an enhanced affinity and selectivity for uranium in acid and complexing media. Work in this direction is currently in progress.Keywords: extraction, MOF, ligand, uranium
Procedia PDF Downloads 154249 Embracing Diverse Learners: A Way Towards Effective Learning
Authors: Mona Kamel Hassan
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Teaching a class of diverse learners poses a great challenge not only for foreign and second language teachers, but also for teachers in different disciplines as well as for curriculum designers. Thus, to contribute to previous research tackling language diversity, the current paper shares the experience of teaching a reading, writing and vocabulary building course to diverse Arabic as a Foreign Language learners in their advanced language proficiency level. Diversity is represented in students’ motivation, their prior knowledge, their various needs and interests, their level of anxiety, and their different learning styles and skills. While teaching this course the researcher adopted the universal design for learning (UDL) framework, which is a means to meet the various needs of diverse learners. UDL stresses the importance of enabling the entire diverse students to gain skills, knowledge, and enthusiasm to learn through the employment of teaching methods that respond to students' individual differences. Accordingly, the educational curriculum developed for this course and the teaching methods employed is modified. First, the researcher made the language curriculum vivid and attractive to inspire students' learning and to keep them engaged in their learning process. The researcher encouraged the entire students, from the first day, to suggest topics of their interest; political, social, cultural, etc. The authentic Arabic texts chosen are those that best meet students’ needs, interests, lives, and sociolinguistic issues, together with the linguistic and cultural components. In class and under the researcher’s guidance, students dig into these topics to find solutions for the tackled issues while working with their peers. Second, to gain equal opportunities to demonstrate learning, role-playing was encouraged to give students the opportunity to perform different linguistic tasks, to reflect and share their diverse interests and cultural backgrounds with their peers. Third, to bring the UDL into the classroom, students were encouraged to work on interactive, collaborative activities through technology to improve their reading and writing skills and reinforce their mastery of the accumulated vocabulary, idiomatic expressions, and collocations. These interactive, collaborative activities help to facilitate student-student communication and student-teacher communication and to increase comfort in this class of diverse learners. Detailed samples of the educational curriculum and interactive, collaborative activities developed, accompanied by methods of teaching employed to teach these diverse learners, are presented for illustration. Results revealed that students are responsive to the educational materials which are developed for this course. Therefore, they engaged in the learning process and classroom activities and discussions effectively. They also appreciated their instructor’s willingness to differentiate the teaching methods to suit students of diverse background knowledge, learning styles, level of anxiety, etc. Finally, the researcher believes that sharing this experience in teaching diverse learners will help both language teachers and teachers in other disciplines to develop a better understanding to meet their students' diverse needs. Results will also pave the way for curriculum designers to develop educational material that meets the needs of diverse learners.Keywords: teaching, language, diverse, learners
Procedia PDF Downloads 94248 Bioleaching of Precious Metals from an Oil-fired Ash Using Organic Acids Produced by Aspergillus niger in Shake Flasks and a Bioreactor
Authors: Payam Rasoulnia, Seyyed Mohammad Mousavi
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Heavy fuel oil firing power plants produce huge amounts of ashes as solid wastes, which seriously need to be managed and processed. Recycling precious metals of V and Ni from these oil-fired ashes which are considered as secondary sources of metals recovery, not only has a great economic importance for use in industry, but also it is noteworthy from the environmental point of view. Vanadium is an important metal that is mainly used in the steel industry because of its physical properties of hardness, tensile strength, and fatigue resistance. It is also utilized in oxidation catalysts, titanium–aluminum alloys and vanadium redox batteries. In the present study bioleaching of vanadium and nickel from an oil-fired ash sample was conducted using Aspergillus niger fungus. The experiments were carried out using spent-medium bioleaching method in both Erlenmeyer flasks and also bubble column bioreactor, in order to compare them together. In spent-medium bioleaching the solid waste is not in direct contact with the fungus and consequently the fungal growth is not retarded and maximum organic acids are produced. In this method the metals are leached through biogenic produced organic acids present in the medium. In shake flask experiments the fungus was cultured for 15 days, where the maximum production of organic acids was observed, while in bubble column bioreactor experiments a 7 days fermentation period was applied. The amount of produced organic acids were measured using high performance liquid chromatography (HPLC) and the results showed that depending on the fermentation period and the scale of experiments, the fungus has different major lixiviants. In flask tests, citric acid was the main produced organic acid by the fungus and the other organic acids including gluconic, oxalic, and malic were excreted in much lower concentrations, while in the bioreactor oxalic acid was the main lixiviant and it was produced considerably. In Erlenmeyer flasks during 15 days fermentation of Aspergillus niger, 8080 ppm citric acid and 1170 ppm oxalic acid was produced, while in bubble column bioreactor over 7 days of fungal growth, 17185 ppm oxalic acid and 1040 ppm citric acid was secreted. The leaching tests using the spent-media obtained from both of fermentation experiments, were performed at the same conditions of leaching duration of 7 days, leaching temperature of 60 °C and pulp density up to 3% (w/v). The results revealed that in Erlenmeyer flask experiments 97% of V and 50% of Ni were extracted while using spent medium produced in bubble column bioreactor, V and Ni recoveries were achieved to 100% and 33%, respectively. These recovery yields indicate that in both scales almost total vanadium can be recovered, while nickel recovery was lower. With help of the bioreactor spent-medium nickel recovery yield was lower than that of obtained from the flask experiments, which it could be due to precipitation of some values of Ni in presence of high levels of oxalic acid existing in its spent medium.Keywords: Aspergillus niger, bubble column bioreactor, oil-fired ash, spent-medium bioleaching
Procedia PDF Downloads 221247 A Hybrid Film: NiFe₂O₄ Nanoparticles in Poly-3-Hydroxybutyrate as an Antibacterial Agent
Authors: Karen L. Rincon-Granados, América R. Vázquez-Olmos, Adriana-Patricia Rodríguez-Hernández, Gina Prado-Prone, Margarita Rivera, Roberto Y. Sato-Berrú
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In this work, a hybrid film based on poly-3-hydroxybutyrate (P3HB) and nickel ferrite (NiFe₂O₄) nanoparticles (NPs) was obtained by a simple and reproducible methodology in order to study its antibacterial and cytotoxic properties. The motivation for this research is the current antimicrobial resistance (RAM). This is a threat to human health and development worldwide. RAM is caused by the emergence of bacterial strains resistant to traditional antibiotics that were used as treatment. Due to this, the need to investigate new alternatives for preventing and treating bacterial infections emerges. In this sense, metal oxide NPs have aroused great interest due to their unique physicochemical properties. However, their use is limited by the nanostructured nature, commonly obtained by chemical and physical synthesis methods, as powders or colloidal dispersions. Therefore, the incorporation of nanostructured materials in polymer matrices to obtain hybrid materials that allow disinfecting and preventing the spread of bacteria on various surfaces. Accordingly, this work presents the synthesis and study of the antibacterial properties of the P3HB@NiFe₂O₄ hybrid film as a potential material to inhibit bacterial growth. The NiFe₂O₄ NPs were previously synthesized by a mechanochemical method. The P3HB and P3HB@NiFe₂O₄ films were obtained by the solvent casting method. The films were characterized by X-ray diffraction (XRD), Raman scattering, and scanning electron microscopy (SEM). The XRD pattern showed that the NiFe₂O₄ NPs were incorporated into the P3HB polymer matrix and retained their nanometric sizes. By energy dispersive X-ray spectroscopy (EDS), it was observed that the NPs are homogeneously distributed in the film. The bactericidal effect of the films obtained was evaluated in vitro using the broth surface method against two opportunistic and nosocomial pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. The bacterial growth results showed that the P3HB@NiFe₂O₄ hybrid film was inhibited by 97% and 96% for S. aureus and P. aeruginosa, respectively. Surprisingly, the P3HB film inhibited both bacterial strains by around 90%. The cytotoxicity of the NiFe₂O₄ NPs, P3HB@NiFe₂O₄ hybrid film, and the P3HB film was evaluated using human skin cells, keratinocytes, and fibroblasts, finding that the NPs are biocompatible. The P3HB film and hybrids are cytotoxic, which demonstrated that although P3HB is known and reported as a biocompatible polymer, under our work conditions, P3HB was cytotoxic. Its bactericidal effect could be related to this activity. Its films are bactericidal and cytotoxic to keratinocytes and fibroblasts, the first barrier of human skin. Despite this, the hybrid film of P3HB@NiFe₂O₄ presents synergy with the bactericidal effect between P3HB and NPs, increasing bacterial inhibition. In addition, NPs decrease the cytotoxicity of P3HB to keratinocytes. The methodology used in this work was successful in producing hybrid films with antibacterial activity. However, future challenges are generated to find relationships between NPs and P3HB that allow taking advantage of their bactericidal properties and do not compromise biocompatibility.Keywords: poly-3-hydroxybutyrate, nanoparticles, hybrid film, antibacterial
Procedia PDF Downloads 74246 State, Public Policies, and Rights: Public Expenditure and Social and Welfare Policies in America, as Opposed to Argentina
Authors: Mauro Cristeche
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This paper approaches the intervention of the American State in the social arena and the modeling of the rights system from the Argentinian experience, by observing the characteristics of its federal budgetary system, the evolution of social public spending and welfare programs in recent years, labor and poverty statistics, and the changes on the labor market structure. The analysis seeks to combine different methodologies and sources: in-depth interviews with specialists, analysis of theoretical and mass-media material, and statistical sources. Among the results, it could be mentioned that the tendency to state interventionism (what has been called ‘nationalization of social life’) is quite evident in the United States, and manifests itself in multiple forms. The bibliography consulted, and the experts interviewed pointed out this increase of the state presence in historical terms (beyond short-term setbacks) in terms of increase of public spending, fiscal pressure, public employment, protective and control mechanisms, the extension of welfare policies to the poor sectors, etc. In fact, despite the significant differences between both countries, the United States and Argentina have common patterns of behavior in terms of the aforementioned phenomena. On the other hand, dissimilarities are also important. Some of them are determined by each country's own political history. The influence of political parties on the economic model seems more decisive in the United States than in Argentina, where the tendency to state interventionism is more stable. The centrality of health spending is evident in America, while in Argentina that discussion is more concentrated in the social security system and public education. The biggest problem of the labor market in the United States is the disqualification as a consequence of the technological development while in Argentina it is a result of its weakness. Another big difference is the huge American public spending on Defense. Then, the more federal character of the American State is also a factor of differential analysis against a centralized Argentine state. American public employment (around 10%) is comparatively quite lower than the Argentinian (around 18%). The social statistics show differences, but inequality and poverty have been growing as a trend in the last decades in both countries. According to public rates, poverty represents 14% in The United States and 33% in Argentina. American public spending is important (welfare spending and total public spending represent around 12% and 34% of GDP, respectively), but a bit lower than Latin-American or European average). In both cases, the tendency to underemployment and disqualification unemployment does not assume a serious gravity. Probably one of the most important aspects of the analysis is that private initiative and public intervention are much more intertwined in the United States, which makes state intervention more ‘fuzzy’, while in Argentina the difference is clearer. Finally, the power of its accumulation of capital and, more specifically, of the industrial and services sectors in the United States, which continues to be the engine of the economy, express great differences with Argentina, supported by its agro-industrial power and its public sector.Keywords: state intervention, welfare policies, labor market, system of rights, United States of America
Procedia PDF Downloads 123245 Waste Scavenging as a Waste-to-Wealth Strategy for Waste Reduction in Port Harcourt City Nigeria: A Mixed Method Study
Authors: Osungwu Emeka
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Until recently, Port Harcourt was known as the “Garden City of Nigeria” because of its neatness and the overwhelming presence of vegetation all over the metropolis. But today, the presence of piles of refuse dotting the entire city may have turned Port Harcourt into a “Garbage City”. Indiscriminate dumping of industrial, commercial and household wastes such as food waste, paper, polythene, textiles, scrap metals, glasses, wood, plastic, etc. at street corners and gutters, is still very common. The waste management problem in the state affects the citizens both directly and indirectly. The dumping of waste along the roadside obstructs traffic and, after mixing with rain water may sip underground with the possibility of the leachate contaminating the groundwater. The basic solid waste management processes of collection, transportation, segregation and final disposal appear to be very inefficient. This study was undertaken to assess waste utilization using metal waste scavengers. Highlighting their activities as a part of the informal sector of the solid waste management system with a view to identifying their challenges, prospects and possible contributions to the solid waste management system in the Port Harcourt metropolis. Therefore, the aim was to understand and assess scavenging as a system of solid waste management in Port Harcourt and to identify the main bottlenecks to its efficiency and the way forward. This study targeted people who engage in scavenging metal scraps across 5 major waste dump sites across Port Harcourt. To achieve this, a mixed method study was conducted to provide both experiential evidence on this waste utilization method using a qualitative study and a survey to collect numeric evidence on this subject. The findings from the qualitative string of this study provided insight on scavenging as a waste utilization activity and how their activities can reduce the gross waste generated and collected from the subject areas. It further showed the nature and characteristics of scavengers in the waste recycling system as a means of achieving the millennium development goals towards poverty alleviation, job creation and the development of a sustainable, cleaner environment. The study showed that in Port Harcourt, the waste management practice involves the collection, transportation and disposal of waste by refuse contractors using cart pushers and disposal vehicles at designated dumpsites where the scavengers salvage metal scraps for recycling and reuse. This study further indicates that there is a great demand for metal waste materials/products that are clearly identified as genuinely sustainable, even though they may be perceived as waste. The market for these waste materials shall promote entrepreneurship as a profitable venture for waste recovery and recycling in Port Harcourt. Therefore, the benefit of resource recovery and recycling as a means of the solid waste management system will enhance waste to wealth that will reduce pollution, create job opportunities thereby alleviate poverty.Keywords: scavengers, metal waste, waste-to-wealth, recycle, Port Harcourt, Nigeria, waste reduction, garden city, waste
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