Search results for: Advanced Encryption Standard (AES)

Authors: Jitendar Kumar Tiwari, Ajay Mandal, N. Sathish, A. K. Srivastava

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Since the last decade, graphene achieved great attention toward the progress of multifunction metal matrix composites, which are highly demanded in industries to develop energy-efficient systems. This study covers the two advanced aspects of the latest scientific endeavor, i.e., graphene as reinforcement in metallic materials and additive manufacturing (AM) as a processing technology. Herein, high-quality graphene and AlSi10Mg powder mechanically mixed by very low energy ball milling with 0.1 wt. % and 0.2 wt. % graphene. Mixed powder directly subjected to the powder bed fusion process, i.e., an AM technique to produce composite samples along with bare counterpart. The effects of graphene on porosity, microstructure, and mechanical properties were examined in this study. The volumetric distribution of pores was observed under X-ray computed tomography (CT). On the basis of relative density measurement by X-ray CT, it was observed that porosity increases after graphene addition, and pore morphology also transformed from spherical pores to enlarged flaky pores due to improper melting of composite powder. Furthermore, the microstructure suggests the grain refinement after graphene addition. The columnar grains were able to cross the melt pool boundaries in case of the bare sample, unlike composite samples. The smaller columnar grains were formed in composites due to heterogeneous nucleation by graphene platelets during solidification. The tensile properties get affected due to induced porosity irrespective of graphene reinforcement. The optimized tensile properties were achieved at 0.1 wt. % graphene. The increment in yield strength and ultimate tensile strength was 22% and 10%, respectively, for 0.1 wt. % graphene reinforced sample in comparison to bare counterpart while elongation decreases 20% for the same sample. The hardness indentations were taken mostly on the solid region in order to avoid the collapse of the pores. The hardness of the composite was increased progressively with graphene content. Around 30% of increment in hardness was achieved after the addition of 0.2 wt. % graphene. Therefore, it can be concluded that powder bed fusion can be adopted as a suitable technique to develop graphene reinforced AlSi10Mg composite. Though, some further process modification required to avoid the induced porosity after the addition of graphene, which can be addressed in future work.

Keywords: graphene, hardness, porosity, powder bed fusion, tensile properties

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Authors: Rithika Sriram, Kiran M. Bhojwani

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Introduction : Tuberculosis of the head and neck has proved to be a diagnostic challenge for otorhinolarynologists around the world. These lesions are often misdiagnosed as cancer. So in order to contribute to a better understanding of these lesions, we have conducted our study among patients affected by TB in the head and neck region with the objective of assessing the various manifestations, presentations, diagnostic techniques, risk factors such as smoking and alcohol consumption, coexisting illnesses and treatment modalities. Materials and Methods: This was a retrospective study conducted over a three year period (2012-2014) in 2 hospitals affliated to Kasturba Medical College in Mangalore, South India. A semi structured proforma was used to capture information from the medical records pertaining to the various objectives of the study such as clinical features and history of smoking. Data was analysed using SPSS version 16.0 and results obtained were depicted as percentages. Chi square test was used to find association between the variables and p<0.05 was considered statistically significant. Results: 104 patients were found to have TB of the head and neck and among them,the most common manifestation was found to be Tubercular Lymphadenitis (86.53%), followed by laryngeal TB (4.8%), submandibular gland TB (3.8%), deep neck space abscess(3.8%) and adenotonsillar TB. FNAC was found to be the gold standard for the diagnosis of TB disease of the lymph node.26% of the patients had coexisting HIV infection and 16.3% of the patients had associated pulmonary TB. More than 20% of the patients were smokers. Most patients were treated using ATT. Conclusion: Tuberculosis affecting regions of head and neck is no longer uncommon. Sufficient knowledge and appropriate diagnostic means is required while dealing with these lesions and must be included in the differential diagnosis of pathological lesions of head and neck.

Keywords: FNAC, Mangalore, smoking, tuberculosis

Procedia PDF Downloads 279

Authors: Martyna Ekiert, Andrzej Mlyniec

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Tendons are the biological structures, which primary function is to transfer force generated by muscles to the bones. Unfortunately, damages of tendons are also one of the most common injuries of the human musculoskeletal system. For the most severe cases of tendon rupture, such as the tear of calcaneus tendon or anterior cruciate ligament of the knee, a surgical procedure is the only possible way of full recovery. Tendons used as biological grafts are usually subjected to the process of deep freezing and subsequent thawing. This, in particular for multiple freezing/thawing cycles, may result in changes of tendon internal structure causing deterioration of mechanical properties of the tissue. Therefore, studies on the influence of freezing on tendons biomechanics, including internal water content in soft tissue, seems to be greatly needed. An experimental study of the influence of freezing on mechanical properties of the tendon was performed on fascicles samples dissected form bovine flexor tendons. The preparation procedure was performed with the presence of 0.9% saline solution in order to prevent an excessive tissue drying. All prepared samples were subjected to the different number of freezing/thawing cycles. For freezing part of the protocol we used -80°C temperature while for slow thawing we used fridge temperature (4°C) combined with equalizing temperatures in the standard state (25°C). After final thawing, the mechanical properties of each sample was examined using cyclic loading test. Our results may contribute for better understanding of negative effects of soft tissues freezing, resulting from abnormal thermal expansion of water. This also may help to determine the limit of freezing/thawing cycles disqualifying tissue for surgical purposes and thus help optimize tissues storage conditions.

Keywords: freezing, soft tissue, tendon, bovine fascicles

Procedia PDF Downloads 222

Authors: Yingjeng James Li, Yun Jyun Ou, Chih Chi Hsu, Chiao-Chih Hu

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A fuel cell is a device that produces electric power by reacting fuel and oxidant electrochemically. There is no pollution produced from a fuel cell if hydrogen is employed as the fuel. Therefore, a fuel cell is considered as a zero emission device and is a source of green power. A membrane electrode assembly (MEA) is the key component of a fuel cell. It is, therefore, beneficial to develop MEAs with high performance. In this study, an MEA for proton exchange membrane fuel cell (PEMFC) was prepared from a 15-micron thick reinforced PEM. The active area of such MEA is 25 cm2. Carbon supported platinum (Pt/C) was employed as the catalyst for both anode and cathode. The platinum loading is 0.6 mg/cm2 based on the sum of anode and cathode. Commercially available carbon papers coated with a micro porous layer (MPL) serve as gas diffusion layers (GDLs). The original thickness of the GDL is 250 μm. It was compressed down to 163 μm when assembled into the single cell test fixture. Polarization curves were taken by using eight different test conditions. At our standard test condition (cell: 70 °C; anode: pure hydrogen, 100%RH, 1.2 stoic, ambient pressure; cathode: air, 100%RH, 3.0 stoic, ambient pressure), the cell current density is 1250 mA/cm2 at 0.6 V, and 2400 mA/cm2 at 0.4 V. At self-humidified condition and cell temperature of 55 °C, the cell current density is 1050 mA/cm2 at 0.6 V, and 2250 mA/cm2 at 0.4 V. Hydrogen crossover rate of the MEA is 0.0108 mL/min*cm2 according to linear sweep voltammetry experiments. According to the MEA’s Pt loading and the cyclic voltammetry experiments, the Pt electrochemical surface area is 60 m2/g. The ohmic part of the impedance spectroscopy results shows that the membrane resistance is about 60 mΩ*cm2 when the MEA is operated at 0.6 V.

Keywords: fuel cell, membrane electrode assembly, proton exchange membrane, reinforced

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Authors: Sidi Ahmed Berrabah

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English as a Medium of Instruction (EMI) is expanding rapidly in the world. A growing volume of research has been dedicated to investigating its introduction, with findings that describe a complex picture and suggest that the practicality and effectiveness of EMI are still the subjects of debate. However, considerably less attention has been given to understanding EMI in a context where its introduction has been discussed but not yet put into practice. One such context is Algeria, where discourses about a potential introduction of EMI have been going on for some time. It is likely that the first courses where EMI is introduced are Business degree programmes. This study aims to examine the current discourses and attitudes towards the potential implementation of EMI and the language practices in Business degree programmes in three Algerian universities. The research is conducted in three different universities in three different regions in Algeria with the aim of including both ‘centre’ and ‘periphery’ Algerian universities. In order to achieve the previous aims, a mixed research paradigm is used. Questionnaires, semi structured interviews, and classroom observations are used to gather data from three participant cohorts: university students of Business, lecturers of Business, and lecturers of English for specific purposes. The findings showed that students and lecturers of Business are found in favour of the introduction of English instead of French or standard Arabic as a medium of instruction. The reason is that English is seen as having internationalisation and instrumental benefits, while French was too closely linked to the colonial history of the country. The favourable attitudes towards EMI, however, seem to contrast with the daily classroom practices at the departments of Business studies, where students and lecturers make practical choices of using their language repertoire based on their linguistic background and skills. Classrooms in the three Algerian universities featured fluid and translanguaging practices that cannot be reduced to a monolingual EMI policy.

Keywords: EMI, Algerian universities, business degree programmes, translanguaging

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Authors: Vinda B. Manurung, Laila Warkhaida, David Hutabarat, Sentanu Wisnuwardhana, Christovik Simatupang, Dhani Sanjaya, Ashadi, Redha B. Putra, Kiki Yustendi

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The geothermal drilling environment presents many obstacles that have limited the use of directional drilling and logging-while-drilling (LWD) technologies, such as borehole washout, mud losses, severe vibration, and high temperature. The case study presented in this paper demonstrates a practice to enhance data logging in geothermal drilling by deploying advanced telemetry and LWD technologies. This operation is aiming continuous improvement in geothermal drilling operations. The case study covers a 12.25-in. hole section of well XX-05 in Pad XX of the Sorik Marapi Geothermal Field. LWD string consists of electromagnetic (EM) telemetry, pressure while drilling (PWD), vibration (DDSr), and acoustic calliper (ACAL). Through this tool configuration, the operator acquired drilling mechanics and caliper logs in real-time and recorded mode, enabling effective monitoring of wellbore stability. Throughout the real-time acquisition, EM-PPM telemetry had provided a three times faster data rate to the surface unit. With the integration of Caliper data and Drilling mechanics data (vibration and ECD -equivalent circulating density), the borehole conditions were more visible to the directional driller, allowing for better control of drilling parameters to minimize vibration and achieve optimum hole cleaning in washed-out or tight formation sequences. After reaching well TD, the recorded data from the caliper sensor indicated an average of 8.6% washout for the entire 12.25-in. interval. Washout intervals were compared with loss occurrence, showing potential for the caliper to be used as an indirect indicator of fractured intervals and validating fault trend prognosis. This LWD case study has given added value in geothermal borehole characterization for both drilling operation and subsurface. Identified challenges while running LWD in this geothermal environment need to be addressed for future improvements, such as the effect of tool eccentricity and the impact of vibration. A perusal of both real-time and recorded drilling mechanics and caliper data has opened various possibilities for maximizing sensor usage in future wells.

Keywords: geothermal drilling, geothermal formation, geothermal technologies, logging-while-drilling, vibration, caliper, case study

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Authors: Michal Biały, Konrad Pietrykowski, Rafal Sochaczewski

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The kinematics and dynamics analysis of crank-piston system of aircraft engine. The object of the study was the high power aircraft engine ASz 62-IR. This engine is produced by a Polish company WSK "PZL-KALISZ" S.A.". All analyzes were performed numerically using CAD and CAE environment. Three-dimensional model of the crank-piston system was developed based on real engine located in the Laboratory of Centre of Innovation and Advanced Technologies of Lublin University of Technology. During the development of the model, the technique of reverse engineering - 3D scanning was used. ASz 62-IR engine is characterized by a radial type of crank-piston system. In this system the cylinders are arranged radially around the circle. This crank-piston system consists of a main connecting rod and eight additional connecting rods. In addition, three-dimensional model consists of a piston pins, pistons and piston rings. As a result of the specific engine design, characteristics of the piston individual movement are slightly different from each other. But the model assumes that they are the same during the analysis. Three-dimensional model of the engine was implemented into the MSC Adams software. The environment of MSC Adams allows for multibody simulation of the dynamic phenomena. This determines the state parameters of the moving elements, among which the load or force distribution on each kinematic node can be distinguished. Materials and characteristic materials parameters were adopted on the basis of commonly used materials for engine parts. The mass values of individual elements were adopted on the basis of real engine parts. The piston gas forces were replaced by calculation of pressure variations recorded during engine tests on the engine test bench. The research the changes of forces acting in the individual kinematic pairs of crank-piston system. The model allows to determine the load on the crankshaft main bearings. This gives the possibility for the main supports forces analysis The model allows for testing and simulation of kinematics and dynamics of a radial aircraft engine. This is the first stage of the work, which aims to numerical simulation of vibration of multi-cylinder aircraft engine. This work has been financed by the Polish National Centre for Research and Development, INNOLOT, under Grant Agreement No. INNOLOT/I/1/NCBR/2013.

Keywords: aircraft engine, CAD, CAE, dynamics, kinematics, MSC Adams, numerical simulation

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Authors: Irma Wani Othman

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The internationalization of higher education in Malaysia mainly focuses to place the implementation of the strategic, comprehensive and integrated range of stakeholders in order to highlight the visibility of Malaysia as a hub of academic excellence. While the concept of 'global citizenship' is used as a two-pronged strategy of aggressive marketing by universities which includes; (i) the involvement of the academic expatriates in stimulating international activities of higher education and (ii) an increase in international student enrollment capacity for the enculturation of science and the development of first class mentality. In this aspect, aspirations for a transnational social movement through global citizenship status to establish the identity of the university community without borders (borderless universities) - regardless of skin colour, thus rationalize and liberalize the universal principles of life and cultural traditions of a nation. The education system earlier referred by the spirit of nationalism is now progressing due to globalization, hence forming a system of higher education that is relevant and generated by the need of all time. However, debates arose when the involvement of global citizenship is said to threaten the ultimate university autonomy in determining the direction of academic affairs and governance of their human resources. Stemming from this debate, this study aims to explore the experience of 'global citizenship' that the academic expatriates and international students in shaping the university's strategic needs and interests which are in line with the transition of contemporary higher education. The objective of this study is to examine the acculturation experience of the global citizen in the form of transnational higher education system and suggest policy and policing IHE which refers directly to the experience of the global citizen. This study offers a detailed understanding of how the university communities assess their expatriation experience, thus becoming useful information for learning and transforming education. The findings also open an advanced perspective on the international mobility of human resources and the implications on the implementation of the policy of internationalization of higher education. The contribution of this study is expected to give new input, thus shift the focus of contextual literature for the internationalization of the education system. Instead of focusing on the purpose of generating income of a university, to a greater understanding of subjective experience in utilizing international human resources hence contributing to the prominent transnational character of higher education.

Keywords: internationalization, global citizens, Malaysia higher education, academic expatriate, international students

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Authors: Sarah K. Basudan, Ragad I. Al Jazzar, Zeinah Sulaihim, Hanan M. Al-Kadri

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Background: Cesarean section has been increasing in recent years, with a wide range of etiologies contributing to this rise. This study aimed to assess the indications, outcomes, and complications in Riyadh, Saudi Arabia. Methods: A Retrospective Cohort study was conducted at King Abdulaziz medical city. The study includes two cohorts: G1 (2009) and G2 (2020) groups who met the inclusion criteria. The data was transferred to the SPSS (statistical package for social sciences) version 24 for analysis. The initial descriptive statistics were run for all variables, including numerical and categorical data. The numerical data were reported as median, and standard deviation and categorical data were reported as frequencies and percentages. Results: The data were collected from 399 women who were divided into two groups, G1(199) and G2(200). The mean age of all participants is 32+-6​; G1 and G2 had significant differences in age means with 30+-6 and 34+-5, respectively, with a p-value of <0.001, which indicates delayed fertility by four years. Moreover, a breech presentation was less likely to occur in G2 (OR 0.64, CI: 0.21-0.62. P<0.001). Nonetheless, maternal causes such as repeated C-sections and maternal medical conditions were more likely to happen in G2 (OR 1.5, CI: 1.04-2.38, p=0.03) and (OR 5.4, CI: 1.12-23.9, P=0.01), respectively. Furthermore, postpartum hemorrhage showed an increase of 12% in G2 (OR 5.4, CI: 2.2-13.4, p<0.001). G2 was more likely to be admitted to the neonatal intensive care unit (NICU) (OR 16, CI: 7.4-38.7) and to special care baby (SCB) (OR 7.2, CI: 3.9-13.1), both with a p-value<0.001 compared to regular nursery admission. Conclusion: There are multiple factors that are contributing to the increase in c section rate in a Saudi tertiary hospitals. The factors were suggested to be previous c-sections, abnormal fetal heart rate, malpresentation, and maternal or fetal medical conditions.

Keywords: cesarean sections, maternal indications, maternal complications, neonatal condition

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Authors: Matthew Heidman, Susan Dallabrida, Analice Costa

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For infant caregivers, choosing an infant formula for their child can be a difficult task in an already stressful environment of caring for a newborn. There exist several channels that influence purchasing decision of infant formula such as, friends and family and their experiences, health care professionals, social media influencers, as well as standard media marketing. This study sought to identify the key channels by which caregivers obtain information regarding infant formula and help them make their purchasing decision. A digital survey was issued for 90 days in the US (n=121) and 30 days in Mexico (n=88) targeting respondents with children ≤4 years of age. Respondents were asked two key questions regarding the influences on their purchasing decisions: 1) “When choosing a formula brand, what do you do to help you make your decision?”, and 2) “When choosing a formula brand, what is most important to you?”. A list of potential answers was provided for each question and respondents were asked to select all that apply to them. Lastly, respondents were provided a 5-point Likert scale and asked to respond to the statement 3) “I am more likely to buy a particular formula brand if my pediatrician recommends it to me”. For question 1, in the US and Mexico, 76% and 95% of respondents respectively, selected “I ask my pediatrician” which represented the top selection. For question 2, 52% and 45% of respondents respectively, selected “On package “Pediatrician Recommended” claim…” which also represented the top selection. For statement 3, 82% and 89% of respondents respectively, stated that they either “somewhat agree” or “strongly agree” with the statement. For infant caregivers, the pediatrician is a very important channel of influence when it comes to purchasing decision of infant formula. Caregivers clearly see the pediatrician as the arbiter of their child’s nutrition and seek their recommendations for infant formula use. For infant formula manufacturers, it is important that they see the pediatrician as the gatekeeper to this market, and they put resources into medical marketing communication to this health care professional group to ensure success.

Keywords: infant formula, pediatrician, purchasing driver, caregiver

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Authors: T. Jivita, M. S. Salmiah

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The aims of this study were to determine the prevalence of smoking, reasons for tried smoking, factors that influence smoking, and knowledge level on health risk among male Tamil primary school students. Seven urban Tamil primary schools in Kuala Lumpur were identified based on cluster sampling. A cross-sectional study was conducted in May 2014 and a total of 380 male children in standard 4 and 5 were selected. Survey included information on history of ever smoking even a puff, smoking a whole cigarette, smoking every day at least for 7 days, reasons for tried smoking, potential factors of smoking and knowledge related to smoking and health. Fifty seven had previously smoked, with a prevalence of 15.0% (95% CI = 11.4, 18.6) and 17 had smoked a whole cigarette (4.5%, 95% CI = 2.42, 6.58) while 8 had at least smoked 7 days continuously (2.1%, 95% CI = 0.66, 3.54). The reasons for tried smoking were because of curiosity (63.2%), it is not allowed (42.6%), it is relaxing (35.2%), it is cool (33.3%), to lose weight (20.4%), style (1.8%), by mistake (0.5%), for prayers purpose (0.3%), given by uncle (0.3%), and introduced by elder brother (0.3%). None of these reasons were associated with age factors (p > 0.05). Of those who had smoked a whole cigarette, 42.9% were significantly influenced by father (χ2 (1) = 6.42, p = 0.040) and 47.8% were significantly influenced by friends (χ2 (2) = 6.27, p = 0.043). Overall 91.5% had good level of knowledge about smoking, where the majority knew that smoking was dangerous to their health. However only 61.7% and 63.1% of them knew that smoking can cause high blood pressure and stroke, respectively. There is no significant different in mean rank between 10 years old and 11 years old students (p=0.987 < 0.05) for level of knowledge, tested by Mann-Whitney U Test. Odds of smoking increased 1.37 times having seen actors smoking (95% CI= 1.01, 1.86), 1.55 times having a father who smokes (95% CI= 1.26, 1.92), 1.64 times having siblings who smokes (95% CI= 1.32, 2.04), and 10.55 times having friends who offered cigarette (95% CI= 4.17, 26.68). As a conclusion, cessation of smoking in family members, who are role models, so as to reduce rates to taking up smoking among children.

Keywords: factors influence, knowledge on smoking, prevalence on smoking, reasons

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Authors: Emanuele Bonamente, Andrea Aquino

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This study presents an innovative design for geothermal heat pumps with the goal of maximizing the system efficiency (COP - Coefficient of Performance), reducing the soil use (e.g. length/depth of geothermal boreholes) and initial investment costs. Based on experimental data obtained from a two-year monitoring of a working prototype implemented for a commercial building in the city of Perugia, Italy, an upgrade of the system is proposed and the performance is evaluated via CFD simulations. The prototype was designed to include a thermal heat storage (i.e. water), positioned between the boreholes and the heat pump, acting as a flywheel. Results from the monitoring campaign show that the system is still capable of providing the required heating and cooling energy with a reduced geothermal installation (approx. 30% of the standard length). In this paper, an optimization of the system is proposed, re-designing the heat storage to include phase change materials (PCMs). Two stacks of PCMs, characterized by melting temperatures equal to those needed to maximize the system COP for heating and cooling, are disposed within the storage. During the working cycle, the latent heat of the PCMs is used to heat (cool) the water used by the heat pump while the boreholes independently cool (heat) the storage. The new storage is approximately 10 times smaller and can be easily placed close to the heat pump in the technical room. First, a validation of the CFD simulation of the storage is performed against experimental data. The simulation is then used to test possible alternatives of the original design and it is finally exploited to evaluate the PCM-storage performance for two different configurations (i.e. single- and double-loop systems).

Keywords: geothermal heat pump, phase change materials (PCM), energy storage, renewable energies

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Authors: Alexa Rakoski, Yun Suk Eo, Cagliyan Kurdak, Priscila F. S. Rosa, Zachary Fisk, Monica Ciomaga Hatnean, Geetha Balakrishnan, Boyoun Kang, Myungsuk Song, Byungki Cho

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Samarium hexaboride (SmB6) is a strongly correlated mixed valence material and Kondo insulator. In the resistance-temperature curve, SmB6 exhibits activated behavior from 4-40 K after the Kondo gap forms. However, below 4 K, the resistivity is temperature independent or weakly temperature dependent due to the appearance of a topologically protected surface state. Current research suggests that the surface of SmB6 is conductive while the bulk is truly insulating, different from conventional 3D TIs (Topological Insulators) like Bi₂Se₃ which are plagued by bulk conduction due to impurities. To better understand why the bulk of SmB6 is so different from conventional TIs, this study employed a new method, called inverted resistance, to explore the lowest temperatures, as well as standard Hall measurements for the rest of the temperature range. In the inverted resistance method, current flows from an inner contact to an outer ring, and voltage is measured outside of this outer ring. This geometry confines the surface current and allows for measurement of the bulk resistivity even when the conductive surface dominates transport (below 4 K). The results confirm that the bulk of SmB6 is truly insulating down to 2 K. Hall measurements on a number of samples show consistent bulk behavior from 4-40 K, but widely varying behavior among samples above 40 K. This is attributed to a combination of the growth process and purity of the starting material, and the relationship between the high and low temperature behaviors is still being explored.

Keywords: bulk transport, Hall effect, inverted resistance, Kondo insulator, samarium hexaboride, topological insulator

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Authors: Faizul Azly Abd Dzubir, Muhammad F. Othman

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Conventional structural health monitoring approach for mechanical equipment uses inspection data from Non-Destructive Testing (NDT) during plant shut down window and fitness for service evaluation to estimate the integrity of the equipment that is prone to crack damage. Yet, this forecast is fraught with uncertainty because it is often based on assumptions of future operational parameters, and the prediction is not continuous or online. Advanced Diagnostic and Prognostic Technology (ADaPT) uses Acoustic Emission (AE) technology and a stochastic prognostic model to provide real-time monitoring and prediction of mechanical defects or cracks. The forecast can help the plant authority handle their cracked equipment before it ruptures, causing an unscheduled shutdown of the facility. The ADaPT employs process historical data trending, finite element analysis, fitness for service, and probabilistic statistical analysis to develop a prediction model for crack initiation and growth due to mechanical damage. The prediction model is combined with live equipment operating data for real-time prediction of the remaining life span owing to fracture. ADaPT was devised at a hot combined feed exchanger (HCFE) that had suffered creep crack damage. The ADaPT tool predicts the initiation of a crack at the top weldment area by April 2019. During the shutdown window in April 2019, a crack was discovered and repaired. Furthermore, ADaPT successfully advised the plant owner to run at full capacity and improve output by up to 7% by April 2019. ADaPT was also used on a coke drum that had extensive fatigue cracking. The initial cracks are declared safe with ADaPT, with remaining crack lifetimes extended another five (5) months, just in time for another planned facility downtime to execute repair. The prediction model, when combined with plant information data, allows plant operators to continuously monitor crack propagation caused by mechanical damage for improved maintenance planning and to avoid costly shutdowns to repair immediately.

Keywords: mechanical damage, cracks, continuous monitoring tool, remaining life, acoustic emission, prognostic model

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Authors: Kirill Filianin, Satu-Pia Reinikainen, Tuomo Sainio

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Frequent measurements of product steam quality create a data overload that becomes more and more difficult to handle. In the current study, plant history data with multiple variables was successfully treated by principal component analysis to detect abnormal process behavior, particularly, in copper solvent extraction. The multivariate model is based on the concentration levels of main process metals recorded by the industrial on-stream x-ray fluorescence analyzer. After mean-centering and normalization of concentration data set, two-dimensional multivariate model under principal component analysis algorithm was constructed. Normal operating conditions were defined through control limits that were assigned to squared score values on x-axis and to residual values on y-axis. 80 percent of the data set were taken as the training set and the multivariate model was tested with the remaining 20 percent of data. Model testing showed successful application of control limits to detect abnormal behavior of copper solvent extraction process as early warnings. Compared to the conventional techniques of analyzing one variable at a time, the proposed model allows to detect on-line a process failure using information from all process variables simultaneously. Complex industrial equipment combined with advanced mathematical tools may be used for on-line monitoring both of process streams’ composition and final product quality. Defining normal operating conditions of the process supports reliable decision making in a process control room. Thus, industrial x-ray fluorescence analyzers equipped with integrated data processing toolbox allows more flexibility in copper plant operation. The additional multivariate process control and monitoring procedures are recommended to apply separately for the major components and for the impurities. Principal component analysis may be utilized not only in control of major elements’ content in process streams, but also for continuous monitoring of plant feed. The proposed approach has a potential in on-line instrumentation providing fast, robust and cheap application with automation abilities.

Keywords: abnormal process behavior, failure detection, principal component analysis, solvent extraction

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Authors: Zane Brough, Claudio Paoloni

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Modern low earth orbit (LEO) satellites that require multi-mission flexibility are highly likely to be repositioned between different operational orbits. While executing this process the satellite may experience high levels of vibration and environmental hazards, exposing the deployed solar panel to dangerous stress levels, fatigue and space debris, hence it is desirable to retract the solar array before satellite repositioning to avoid damage or failure. Furthermore, to accommodate for today's technological world, the power demand of a modern LEO satellite is rapidly increasing, which consequently provides pressure upon the design of the satellites solar array system to conform to the strict volume and mass limitations. A novel concept of deployable/retractable hybrid solar array system, aimed to provide a greater power to volume ratio while dramatically reducing the disadvantages of system mass and cost is proposed. Taking advantage of the new lightweight technology in solar panels, a mechanical system composed of both rigid and flexible solar panels arranged within a petal formation is proposed to yield a stowed to deployment area ratio up to at least 1:7, which improves the power density dramatically. The system consists of five subsystems, the outer ones based on a novel eight-petal configuration that provides a large surface and supports the flexible solar panels. A single cable and spool based hinge mechanism were designed to synchronously deploy/retract the panels in a safe, simple and efficient manner while the mass compared to the previous systems is considerably reduced. The relevant challenge to assure a smooth movement is resolved by a proper minimization of the gearing system and the use of a micro-controller system. A prototype was designed by 3D simulators and successfully constructed and tested. Further design works are in progress to implement an epicyclical gear hinge mechanism, which will further reduce the volume, mass and complexity of the system significantly. The proposed system due to an effective and reliable mechanism provides a large active surface, whilst being very compact. It could be extremely advantageous for use as ground portable solar panel system.

Keywords: mechatronic engineering, satellite, solar panel, deployable/retractable mechanism

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Authors: Rose C.Anamezie, Mishack T. Gumbo

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Physics learners’ poor retention, which culminates in poor achievement due to teaching approaches that are unrelated to learners’ in non-Western cultures, warranted the study. The tenet of this study was to determine the effectiveness of the ethnoscience-based teaching (EBT) approach on learners’ retention in the Physics concept of Optics in the Awka Education zone of Anambra State- Nigeria. Two research questions and three null hypotheses tested at a 0.05 level of significance guided the study. The design adopted for the study was Quasi-experimental. Specifically, a non-equivalent control group design was adopted. The population for the study was 4,825 SS2 Physics learners in the zone. 160 SS2 learners were sampled using purposive and random sampling. The experimental group was taught rectilinear propagation of light (RPL) using the EBT approach, while the control group was taught the same topic using the lecture method. The instrument for data collection was the 50 Physics Retention Test (PRT) which was validated by three experts and tested for reliability using Kuder-Richardson’s formula-20, which yielded coefficients of 0.81. The data were analysed using mean, standard deviation and analysis of co-variance (p< .05). The results showed higher retention for the use of the EBT approach than the lecture method, while there was no significant gender-based factor in the learners’ retention in Physics. It was recommended that the EBT approach, which bridged the gender gap in Physics retention, be adopted in secondary school teaching and learning since it could transform science teaching, enhance learners’ construction of new science concepts based on their existing knowledge and bridge the gap between Western science and learners’ worldviews.

Keywords: Ethnoscience-based teaching, optics, rectilinear propagation of light, retention

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Authors: Faseluka Olamide Tope

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Giving quality education to students with special needs requires that all necessary resources should be harnessed and digital devices has become important part of resources used as instructional materials in educating students with special needs. Teachers who will make use of these technologies are considered as a part of the most important elements in any educational programme and the effective usage of these technologies largely depends on them. Out of numerous determinants of the effective use of these digital devices, this study examines teachers’ attitude and knowledge as predictors of effective use of digital technology for education of special needs student in Oyo state, Nigeria. The descriptive survey research design of the expo-facto type was adopted for the study, using simple random sampling technique. The study was carried out among sixty (60) participants. Two research questions and two research hypotheses were formulated and used. The data collected through the research instruments for the study were analysedusing frequency, percentage, mean and standard deviation, Pearson, Product, Moment Correlation (PPMC) and Multiple Regression Analysis. The study revealed a significant relationship between teachers attitude (50, < 0.05) and effective use of digital technologies for special needs students. Furthermore, there was a significant contribution F (F=4.289; R=0.876 and R2 =0.758) in the joint contribution of the independent variable  (teacher’s attitude and teacher’s knowledge) and dependent variable (effective use of digital technologies) while teachers knowledge have the highest contribution(b=7.926, t=4.376), the study therefore revealed that teachers attitude and knowledge are potent factors that predicts the effective usage of digital technologies for the education of special needs student. The study recommended that due to the ever-changing nature of technology which comes with new features, teachers should be equipped with appropriate knowledge in order to effectively make use of them and teachers should also develop right attitude toward the use of digital technologies

Keywords: teachers’ knowledge, teachers’ attitude, digital devices, special needs students

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Authors: Ahmad Idris, Armaya`u Suleiman Labo, Ado Yusuf Abdulfatah, Murtala Umar

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Super pave is the short form of Superior Performing Asphalt Pavement and represents a basis for specifying component materials, asphalt mixture design and analysis, and pavement performance prediction. This new technology is the result of long research projects conducted by the strategic Highway Research program (SHRP) of the Federal Highway Administration. This research was aimed at examining the suitability of Aggregates found in Kano for used in super pave design method. Aggregates samples were collected from different sources in Kano Nigeria and their Engineering properties, as they relate to the SUPERPAVE design requirements were determined. The average result of Coarse Aggregate Angularity in Kano was found to be 87% and 86% of one fractured face and two or more fractured faces respectively with a standard of 80% and 85% respectively. Fine Aggregate Angularity average result was found to be 47% with a requirement of 45% minimum. A flat and elongated particle which was found to be 10% has a maximum criterion of 10%. Sand equivalent was found to be 51% with the criteria of 45% minimum. Strength tests were also carried out, and the results reflect the requirements of the standards. The tests include Impact value test, Aggregate crushing value and Aggregate Abrasion tests and the results are 27.5%, 26.7% and 13% respectively with a maximum criteria of 30%. Specific gravity was also carried out and the result was found to have an average value of 2.52 with a criterion of 2.6 to 2.9 and Water absorption was found to be 1.41% with maximum criteria of 0.6%. From the study, the result of the tests indicated that the aggregates properties have met the requirements of Super pave design method based on the specifications of ASTMD 5821, ASTM D 4791, AASHTO T176, AASHTO T33 and BS815.

Keywords: aggregates, construction, road design, super pave

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Authors: Akinrogunde Omolere Moses

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A plethora of studies indicated that teaching and learning of the physical sciences in the Further Education and Training (FET) Phase (Grades 10–12) have long been declared problematic in South Africa. For instance, the results from the National Senior Certificate Matric Examination in Physical Sciences, especially in the questions related to practical skills, more specifically, electric circuits, have been unsatisfactory in the past decades. Learner difficulties in understanding electric circuits are well stated. Thus, this study appraised the difficulties Grade 12 Educators often face in understanding Electric Circuits in Umgungundlovu, District of Kwazulu-Natal, South Africa. A mixed-methods research methodology was employed, while a total of 30 schools were sampled, including Ex-Model C, Independent Exam Board, community, rural, and deep rural schools. Data were collected through semi-structured questionnaires. The findings revealed that a large percentage of the Grade 12 physical sciences educators have difficulties with the Grade 9 and 12 physical sciences content. It was also observed that most of the educators who had difficulties were unable to detect the type of difficulties learners would experience; as a result, they were unable to explain why learners experience such difficulties. The results also showed that only those educators with more experience in teaching the physical sciences were able to provide clearer explanations of both the why and how of dealing with learner difficulties with this section on electric circuits. The study recommended that there is a need to recruit more qualified educators, with at least a Bachelor of Science in Physics in particular, in order to combat the misconceptions. Also, Educators with an inadequate understanding of physical sciences should be orientated in order to meet the standard of classroom practice.

Keywords: grade 12 educators' difficulties, electric circuits, learners' difficulties, educators understanding of EC.

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Authors: Abul Kalam Azad

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Water security has become an increasingly important issue both at the national and international levels. Bangladesh having an abundance of water during monsoon while the shortage of water during the dry season is far from being water secured. Though water security has been discussed discretely at a different level but a holistic effort to ensure water security is yet to be made. The elements of water security such as sectoral demands of water, conflicting requirements amongst the sectors, balancing between demand and supply including the quality of water can best be understood and managed in a catchment as it is the standard functioning unit. The Arial Khan River catchment consists of parts of Faridpur, Madaripur, Shariatpur and Barishal districts have all the components of water demands such as agriculture, domestic, commercial, industrial, forestry, fisheries, navigation or recreation and e-flow requirements. Based on secondary and primary data, water demands of various sectors have been determined. CROPWAT 8.0 has been used to determine the Agricultural Water Demand. Mean Annual Flow (MAF) and Flow Duration Curve (FDC) have been used to determine the e-flow requirements. Water Evaluation and Planning System (WEAP) based decision support tool as part of Integrated Water Resources Management (IWRM) has been utilized for ensuring the water security of the Arial Khan River catchment. Studies and practice around the globe connected with water security were consulted to mitigate the pressure on demand and supply including the options available to ensure the water security. Combining all the information, a framework for ensuring water security has been suggested for Arial Khan River catchment which can further be projected to river basin as well as for the country. This will assist planners and researchers to introduce the model for integrated water resources management of any catchment/river basins.

Keywords: water security, water demand, water supply, WEAP, CROPWAT

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Authors: Genesis F. Dela Cruz, Liza C. Costa

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The study is concerned with the Risk factors of dropping out among Grade VII students for SY 2012-2013. A total of 87 Grade VII Students-At-Risk-of-Dropping Out (SARDOs) were involved in this study. The descriptive survey method was used in this study. A 50-item questionnaire was used in data gathering. Expert validation was done to determine the validity and reliability of the instrument. The study used Chi Square, Kruskal Wallis Test and Mann Whitney Test in the statistical treatment of data. The study revealed that the respondents are within the standard age limit for Grade VII students in the Philippines which is 13 years old. Males more than females usually becomes SARDOs. SARDOs come from low economic status and complete families contrary to the common belief that they came from single-parent families. The study also showed that parent’s involvement in educating their children on family-related factors contributed to the very good perception on the family related factors. Based on age, there are no significant differences in their perception of the four major recognized risk factors for dropping out among all ages. There are no significant differences in their perception of the family, individual and community related factors for dropping out based on sex. However, females have a more favorable perception when it comes to school related factors. No significant differences in their perception of dropping out were also noted when they are classified according to distance of school from home. The respondents do not differ in their perception on family, individual and community related factors when they are classified according to type of family. When surveyed regarding the respondents’ reason for being absent, it was found out that laziness and being late are the two major reasons. Respondents also perceived remedial and tutorial classes as school-initiated intervention measure to prevent school disengagement or dropping out.

Keywords: drop-out, guidance and counseling, school initiated intervention, students at risk of dropping out

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Authors: Ahmad Abdi, M. Golzadeh Gangeraj, Alireza Barari, S. Shirali, S. Amini

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Aims: Diabetes is one of the common metabolic diseases in the world that has the dire adverse effects such as nephropathy, retinopathy and cardiovascular problems. Pharmaceutical and non-pharmaceutical strategies for control and treatment of diabetes are provided. Exercise and nutrition as non-drug strategies for the prevention and control of diabetes are considered. Exercises may increase oxidative stress and myocardium injury, thus it is necessary to take nutrition strategies to help diabetic athletes. Methods: This study was a semi-experimental research. Therefore, 24 men with type 2 diabetes were selected and randomly divided in four groups (1. control, 2. saffron extract, 3. aerobic exercises, 4. compound aerobic exercises and saffron extract). Saffron extract with 100 mg/day was used. Aerobic exercises, three days a week, for eight weeks, with 55-70% of maximum heart rate were performed. At the end, levels of Heart-type fatty acid-binding protein (HFABP) and Troponin T were measured. Data were analyzed by Paired t, One-way ANOVA and Tukey tests. Results: The serum Troponin T increased significantly in saffron extract, aerobic exercises and compound saffron extract -aerobic exercises in type 2 diabetic men(P=0.024, P =0.013, P=0.005 respectively). Saffron extract consumption (100 mg/day) and aerobic exercises did not significantly influence the serum HFABP (P =0.365, P =0.188 respectively). But serum HFABP decreased significantly in compound saffron extract -aerobic exercises group (P =0.003). Conclusions: Raised cardiac Troponin T and HFABP concentration accepted as the standard biochemical markers for the diagnosis of cardiac injury. Saffron intake may beneficially protect the myocardium from injuries. Compound saffron extract -aerobic exercises can decrease levels of Troponin T and HFABP in men with type 2 diabetes.

Keywords: Saffron, aerobic exercises, type 2 diabetes, HFABP, troponin T

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Authors: Abobakr Khidir Ziyada, Cecilia Devi Wilfred

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In the present work, a new series of 3-propanenitrile imidazolium-based Room Temperature Ionic Liquids (RTILs), incorporating dioctyl sulfosuccinate (DOSS) were prepared by reacting imidazole with acrylonitrile and then reacting the product with allyl chloride, 2-chloroethanol, and benzyl chloride. After the reaction had been completed, metathesis reaction was carried out using sodium dioctyl sulfosuccinate. The densities and viscosities of the present RTILs were measured at atmospheric pressure at T=293.15 to 353.15 K, the refractive index was measured at T=293.15 to 333.15 K, whereas, the start and decomposition temperatures were determined at heating rate 10°C. min^-1. The thermal expansion coefficient, densities at a range of temperatures and pressures, molecular volume, molar refraction, standard entropy and the lattice energy of these RTILs were also estimated. The present RTILs showed higher densities, similar refractive indices, and higher viscosities compared to the other 1-alkyl-3-propanenitrile imidazolium-based RTILs. The densities of the present synthesized RTILs are lower compared to the other nitrile-functionalized ILs. These present RTILs showed a weak temperature dependence on the thermal expansion coefficients, αp=5.0 × 10^−4 to 7.50 × 10−4 K^-1. Empirical correlations were proposed to represent the present data on the physical properties. The lattice energy for the present RTILs was similar to other nitrile–based imidazolium RTILs. The present RTILs showed very high molar refraction when compared similar RTILs incorporating other anions.

Keywords: dioctyl sulfosuccinate, nitrile ILs, 3-propanenitrile, anion, room temperature ionic liquids, RTIL

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Authors: Jo Angouri, Charlotte Kennedy, Shawnea Ting, David Rawlinson, Matthew Booker, Nigel Rees

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Ambulance services need to balance the large volume of emergency (999 in the UK) calls they receive (e.g., West Midlands Ambulance Service reports per day about 4,000 999 calls; about 679,000 calls per year are received in Wales), with dispatching limited resource for on-site intervention to the most critical cases. The process by which Emergency Medical Dispatch (EMD) decisions are made is related to risk assessment and involves the caller and call-taker as well as clinical teams negotiating risk levels on a case-by-case basis. Medical Priority Dispatch System (MPDS – also referred to as Advanced Medical Priority Dispatch System AMPDS) are used in the UK by NHS Trusts (e.,g WAST) to process and prioritise 999 calls. MPDS / AMPDS provide structured protocols for call prioritisation and call management. Protocols/policy frameworks have not been examined before in the way we propose in our project. In more detail, the risk factors that play a role in the EMD negotiation between the caller and call-taker have been analysed in both medical and social science research. Research has focused on the structural, morphological and phonological aspects that could improve, and train, human-to-human interaction or automate risk detection, as well as the medical factors that need to be captured from the caller to inform the dispatch decision. There are two significant gaps in our knowledge that we address in our work: 1. the role of backstage clinical teams in translating the caller/call-taker interaction in their internal risk negotiation and, 2. the role of policy frameworks, protocols and regulations in the framing of institutional priorities and resource allocation. We take a multi method approach and combine the analysis of 999 calls with the analysis of policy documents. We draw on interaction analysis, corpus methodologies and thematic analysis. In this paper, we report on our preliminary findings and focus in particular on the risk factors we have identified and the relationship with the regulations that create the frame within which teams operate. We close the paper with implications of our study for providing evidence-based policy intervention and recommendations for further research.

Keywords: emergency (999) call, interaction analysis, discourse analysis, ambulance dispatch, medical discourse

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Authors: R. Kerbachi, S. Chikhi, M. Boughedaoui

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The study presents an analysis of the Algerian vehicle fleet and resultant emissions. The emission measurement of air pollutants emitted by road transportation (CO, THC, NOX and CO2) was conducted on 17 light duty vehicles in real traffic. This sample is representative of the Algerian light vehicles in terms of fuel quality (gasoline, diesel and liquefied petroleum gas) and the technology quality (injection system and emission control). The experimental measurement methodology of unit emission of vehicles in real traffic situation is based on the use of the mini-Constant Volume Sampler for gas sampling and a set of gas analyzers for CO2, CO, NOx and THC, with an instrumentation to measure kinematics, gas temperature and pressure. The apparatus is also equipped with data logging instrument and data transfer. The results were compared with the database of the European light vehicles (Artemis). It was shown that the technological injection liquefied petroleum gas (LPG) has significant impact on air pollutants emission. Therefore, with the exception of nitrogen oxide compounds, uncatalyzed LPG vehicles are more effective in reducing emissions unit of air pollutants compared to uncatalyzed gasoline vehicles. LPG performance seems to be lower under real driving conditions than expected on chassis dynamometer. On the other hand, the results show that uncatalyzed gasoline vehicles emit high levels of carbon monoxide, and nitrogen oxides. Overall, and in the absence of standards in Algeria, unit emissions are much higher than Euro 3. The enforcement of pollutant emission standard in developing countries is an important step towards introducing cleaner technology and reducing vehicular emissions.

Keywords: on-board measurements of unit emissions of CO, HC, NOx and CO2, light vehicles, mini-CVS, LPG-fuel, artemis, Algeria

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Authors: B. Samuel Raj, Solomon R. D. Jebakumar

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Microbial fuel cells (MFCs) are an emerging and promising method for achieving sustainable energy since they can remove contaminated organic matter and simultaneously generate electricity. Our approach was driven in three different ways like Bacterial fuel cell, Soil Microbial fuel cell (Soil MFC) and Plant Microbial fuel cell (Plant MFC). Bacterial MFC: Sulphate reducing bacteria (SRB) were isolated and identified as the efficient electricigens which is able to produce ±2.5V (689mW/m2) and it has sustainable activity for 120 days. Experimental data with different MFC revealed that high electricity production harvested continuously for 90 days 1.45V (381mW/m2), 1.98V (456mW/m2) respectively. Biofilm formation was confirmed on the surface of the anode by high content screening (HCS) and scanning electron Microscopic analysis (SEM). Soil MFC: Soil MFC was constructed with low cost and standard Mudwatt soil MFC was purchased from keegotech (USA). Vermicompost soil (V1) produce high energy (± 3.5V for ± 400 days) compared to Agricultural soil (A1) (± 2V for ± 150 days). Biofilm formation was confirmed by HCS and SEM analysis. This finding provides a method for extracting energy from organic matter, but also suggests a strategy for promoting the bioremediation of organic contaminants in subsurface environments. Our Soil MFC were able to run successfully a 3.5V fan and three LED continuously for 150 days. Plant MFC: Amaranthus candatus (P1) and Triticum aestivium (P2) were used in Plant MFC to confirm the electricity production from plant associated microbes, four uniform size of Plant MFC were constructed and checked for energy production. P2 produce high energy (± 3.2V for 40 days) with harvesting interval of two times and P1 produces moderate energy without harvesting interval (±1.5V for 24 days). P2 is able run 3.5V fan continuously for 10days whereas P1 needs optimization of growth conditions to produce high energy.

Keywords: microbial fuel cell, biofilm, soil microbial fuel cell, plant microbial fuel cell

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Authors: Sugene Kim

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The English articles are taught as a binary system based on nominal countability and definiteness. Despite the detailed rules of prescriptive grammar, it has been consistently reported in the literature that their correct usage is extremely difficult to master even for advanced learners of English as a second language (ESL) or a foreign language (EFL). Given that an English sentence (except for an imperative) cannot be constructed without a noun, which is always paired with one of the indefinite, definite, and zero articles; it is essential to understand specifically what causes ESL/EFL learners to misuse them. To that end, this study examined EFL learners’ article use employing a one-group pre–post-test design. Forty-three Korean college students received instruction on correct English article usage for two 75-minute classes employing the binary schema set up for the study. They also practiced in class how to apply the rules as instructed. Then, the participants were assigned a forced-choice elicitation task, which was also used as a pre-test administered three months prior to the instruction. Unlike the pre-test on which they only chose the correct article for each of the 40 items, the post-instruction task additionally asked them to give written accounts of their decision-making procedure to choose the article as they did. The participants’ performance was scored manually by checking whether the answer given is correct or incorrect, and their written comments were first categorized using thematic analysis and then ranked by frequency. The analyses of the performance on the two tasks and the written think-aloud data suggested that EFL learners exhibit fluctuation between specificity and definiteness, overgeneralizing the use of the definite article for almost all cataphoric references. It was apparent that they have trouble distinguishing from the two concepts possibly because the former is almost never introduced in the grammar books or classes designed for ESL/EFL learners. Particularly, most participants were found to be ignorant of the possibility of using nouns as [+specific, –definite]. Not surprisingly, the correct answer rates for such nouns averaged out at 33% and 46% on the pre- and post-tests, respectively, which narrowly reach half the overall mean correct answer rates of 65% on the pre-test and 81% on the post-test. In addition, correct article use for specific indefinites was most impermeable to instruction when compared with nouns used as [–specific, –definite] or [± specific, +definite]. Such findings underline the necessity for expanding the binary schema to a ternary form that incorporates the specificity feature, albeit not morphologically marked in the English language.

Keywords: countability, definiteness, English articles, specificity, ternary system

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Authors: Omoruyi Gold Idemudia, Alexander P. Sadimenko

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The synthesis of N-heterocycles with novel properties, having broad spectrum biological activities that may become alternative medicinal drugs, have been attracting a lot of research attention due to the emergence of medicinal drug’s limitations such as disease resistance and their toxicity effects among others. Acylpyrazolones have been employed as pharmaceuticals as well as analytical reagent and their application as coordination complexes with transition metal ions have been well established. By way of a condensation reaction with amines acylpyrazolone ketones form a more chelating and superior group of compounds known as azomethines. 4-propyl-3-methyl-1-phenyl-2-pyrazolin-5-one was reacted with phenylhydrazine to get a new phenylhydrazone which was further reacted with aqueous solutions of palladium and platinum salts, in an effort towards the discovery of transition metal based synthetic drugs. The compounds were characterized by means of analytical, spectroscopic, thermogravimetric analysis TGA, as well as x-ray crystallography. 4-propyl-3-methyl-1-phenyl-2-pyrazolin-5-one phenylhydrazone crystallizes in a triclinic crystal system with a P-1 (No. 2) space group based on x-ray crystallography. The bidentate ON ligand formed a square planar geometry on coordinating with metal ions based on FTIR, electronic and NMR spectra as well as magnetic moments. Reported compounds showed antibacterial activities against the nominated bacterial isolates using the disc diffusion technique at 20 mg/ml in triplicates. The metal complexes exhibited a better antibacterial activity with platinum complex having an MIC value of 0.63 mg/ml. Similarly, ligand and complexes also showed antioxidant scavenging properties against 2, 2-diphenyl-1-picrylhydrazyl DPPH radical at 0.5mg/ml relative to ascorbic acid (standard drug).

Keywords: acylpyrazolone, antibacterial studies, metal complexes, phenylhydrazone, spectroscopy

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Authors: P. Abachi, T. W. Coyle, P. S. Musavi Gharavi

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By applying coating onto a structural component, the corrosion and/or wear resistance requirements of the surface can be fulfilled. Since the layer adhesion of the coating influences the mechanical integrity of the coat/substrate interface during the service time, it should be examined accurately. At the present work, the tensile bonding strength of the 316 stainless steel plasma sprayed coating on aluminum substrate was determined by using tensile adhesion test, TAT, specimen. The interfacial fracture toughness was specified using four-point bend specimen containing a saw notch and modified chevron-notched short-bar (SB) specimen. The coating microstructure and fractured specimen surface were examined by using scanning electron- and optical-microscopy. The investigation of coated surface after tensile adhesion test indicates that the failure mechanism is mostly cohesive and rarely adhesive type. The calculated value of critical strain energy release rate proposes relatively good interface status. It seems that four-point bending test offers a potentially more sensitive means for evaluation of mechanical integrity of coating/substrate interfaces than is possible with the tensile test. The fracture toughness value reported for the modified chevron-notched short-bar specimen testing cannot be taken as absolute value because its calculation is based on the minimum stress intensity coefficient value which has been suggested for the fracture toughness determination of homogeneous parts in the ASTM E1304-97 standard. 

Keywords: bonding strength, four-point bend test, interfacial fracture toughness, modified chevron-notched short-bar specimen, plasma sprayed coating, tensile adhesion test

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