Search results for: stock price exposure
999 Histopathological and Biochemical Investigations of Protective Role of Honey in Rats with Experimental Aflatoxicosis
Authors: Turan Yaman, Zabit Yener, Ismail Celik
Abstract:
The aim of this study was to investigate the antioxidant properties and protective role of honey, considered a part of traditional medicine, against carcinogen chemical aflatoxin (AF) exposure in rats, which were evaluated by histopathological changes in liver and kidney, measuring level of serum marker enzymes [aspartate aminotransferase (AST), alanin aminotransferase (ALT), gamma glutamil transpeptidase (GGT)], antioxidant defense systems [Reduced glutathione (GSH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)], and lipid peroxidation content in liver, erythrocyte, brain, kidney, heart and lungs. For this purpose, a total of eighteen healthy Sprague-Dawley rats were randomly allocated into three experimental groups: A (Control), B (AF-treated) and C (AF+honey-treated). While rats in group A were fed with a diet without AF, B, and C groups received 25 µg of AF/rat/day, where C group additionally received 1 mL/kg of honey by gavage for 90 days. At the end of the 90-day experimental period, we found that the honey supplementation decreased the lipid peroxidation and the levels of enzyme associated with liver damage, increased enzymatic and non-enzymatic antioxidants in the AF+honey-treated rats. Hepatoprotective and nephroprotective effects of honey is further substantiated by showing almost normal histological architecture in AF+honey-treated group, compared to degenerative changes in the liver and kidney of AF-treated rats. Additionally, honey supplementation ameliorated antioxidant defense systems and lipid peroxidation content in other tissues of AF+honey-treated rats. In conclusion, the present study indicates that honey has a hepatoprotective and nephroprotective effect in rats with experimental aflatoxicosis due to its antioxidant activity.Keywords: aflatoxicosis, honey, histopathology, malondialdehyde, antioxidant, rat
Procedia PDF Downloads 337998 Minimizing Unscheduled Maintenance from an Aircraft and Rolling Stock Maintenance Perspective: Preventive Maintenance Model
Authors: Adel A. Ghobbar, Varun Raman
Abstract:
The Corrective maintenance of components and systems is a problem plaguing almost every industry in the world today. Train operators’ and the maintenance repair and overhaul subsidiary of the Dutch railway company is also facing this problem. A considerable portion of the maintenance activities carried out by the company are unscheduled. This, in turn, severely stresses and stretches the workforce and resources available. One possible solution is to have a robust preventive maintenance plan. The other possible solution is to plan maintenance based on real-time data obtained from sensor-based ‘Health and Usage Monitoring Systems.’ The former has been investigated in this paper. The preventive maintenance model developed for train operator will subsequently be extended, to tackle the unscheduled maintenance problem also affecting the aerospace industry. The extension of the model to the aerospace sector will be dealt with in the second part of the research, and it would, in turn, validate the soundness of the model developed. Thus, there are distinct areas that will be addressed in this paper, including the mathematical modelling of preventive maintenance and optimization based on cost and system availability. The results of this research will help an organization to choose the right maintenance strategy, allowing it to save considerable sums of money as opposed to overspending under the guise of maintaining high asset availability. The concept of delay time modelling was used to address the practical problem of unscheduled maintenance in this paper. The delay time modelling can be used to help with support planning for a given asset. The model was run using MATLAB, and the results are shown that the ideal inspection intervals computed using the extended from a minimal cost perspective were 29 days, and from a minimum downtime, perspective was 14 days. Risk matrix integration was constructed to represent the risk in terms of the probability of a fault leading to breakdown maintenance and its consequences in terms of maintenance cost. Thus, the choice of an optimal inspection interval of 29 days, resulted in a cost of approximately 50 Euros and the corresponding value of b(T) was 0.011. These values ensure that the risk associated with component X being maintained at an inspection interval of 29 days is more than acceptable. Thus, a switch in maintenance frequency from 90 days to 29 days would be optimal from the point of view of cost, downtime and risk.Keywords: delay time modelling, unscheduled maintenance, reliability, maintainability, availability
Procedia PDF Downloads 136997 Transmission of Intergenerational Trauma: Protecting Those who Still Suffer from Pain of their Ancestors’ Trauma
Authors: Bonnie Pollak
Abstract:
As the world continues to suffer grievous injuries, future generations will suffer from trauma that was inflicted on innocent victims. Trauma can result from refugees fleeing their homes, exposure to warfare, loss of loved ones, and lack of shelter and basic necessities. The Holocaust continues to cause pain even though WWII ended nearly 80 years ago. One cannot forget the inhumane treatment and murder of relatives. The pain and trauma may continue for generations. The purpose of the Final Solution was to eliminate Jews in totality. Though Hitler’s plan was not successful, he managed to cause trauma that will continue with no end date in sight. “The Effects of Trauma and Secondary Trauma,” Trauma can cause life-long challenges, eating disorders, cardiovascular disease, cancer, sleeping difficulties, fear of going outside, guilt, separation problems, and epigenetic changes. Secondary Trauma, witnessing a loved one in danger or hearing about the danger, can cause similar symptoms as seen in primary trauma. The transmission of trauma was demonstrated in children of Holocaust survivors and in communities where oppression was commonplace. We are witnessing a repeat of widescale death and horrific injuries today in Ukraine and in other parts of the world, where concern for pain and trauma is not acknowledged by perpetrators. Lessons from the Holocaust can be applied to help others who have been traumatized by widescale terrorism resulting in death of loved ones, loss of home and shelter, food and other life-sustaining measures. The world must help victims by providing basic necessities but also by using trauma-informed care, focusing on strength and resilience, and helping individuals to feel pride in their identity.Keywords: transmission of intergenerational trauma, impact on religious beliefs and practices, 2nd generation, identity
Procedia PDF Downloads 115996 The Effects of Ellagic Acid on Rat Liver Induced Tobacco Smoke
Authors: Nalan Kaya, Elif Erdem, Mehmet Ali Kisacam, Gonca Ozan, Enver Ozan
Abstract:
Tobacco smokers continuously inhale thousands of carcinogens and free radicals. It is estimated that about 1017 oxidant molecules are present in each puff of tobacco smoke. It is known that smoking has adverse effects on the structure and functions of the liver. Ellagic acid (EA) has antioxidant, antiapoptotic, anticarcinogenic, antibacterial and antiinflammatory effects. The aim of our study was to investigate the possible protective effect of ellagic acid against tobacco smoke-mediated oxidative stress in the rat liver. Twenty-four male adult (8 weeks old) Spraque-Dawley rats were divided randomly into 4 equal groups: group I (control), group II (tobacco smoke), group III (tobacco smoke + corn oil) and group IV (tobacco smoke + ellagic acid). The rats in group II, III and IV, were exposed to tobacco smoke 1 hour twice a day for 12 weeks. In addition to tobacco smoke exposure, 12 mg/kg ellagic acid (dissolved in corn oil), was applied to the rats in group IV by oral gavage. An equal amount of corn oil used in solving ellagic acid was applied to the rats by oral gavage in group III. At the end of the experimental period, rats were decapitated, and liver tissues were removed. Histological and biochemical analyzes were performed. Sinusoidal dilatation, inflammatory cell infiltration in portal area, increased Kuppfer cells were examined in tobacco smoke group and tobacco smoke+ corn oil groups. The results, observed in tobacco smoke and tobacco smoke+corn oil groups, were found significantly decreased in tobacco smoke+EA group. Group-II and group-III MDA levels were significantly higher, and GSH activities were not different than group-I. Compared to group-II, group-IV MDA level was decreased, and GSH activities was increased significantly. The results indicate that ellagic acid could protect the liver tissue from the tobacco smoke harmful effects.Keywords: ellagic acid, liver, rat, tobacco smoke
Procedia PDF Downloads 302995 Assessing Perinatal Mental Illness during the COVID-19 Pandemic: A Review of Measurement Tools
Authors: Mya Achike
Abstract:
Background and Significance: Perinatal mental illness covers a wide range of conditions and has a huge influence on maternal-child health. Issues and challenges with perinatal mental health have been associated with poor pregnancy, birth, and postpartum outcomes. It is estimated that one out of five new and expectant mothers experience some degree of perinatal mental illness, which makes this a hugely significant health outcome. Certain factors increase the maternal risk for mental illness. Challenges related to poverty, migration, extreme stress, exposure to violence, emergency and conflict situations, natural disasters, and pandemics can exacerbate mental health disorders. It is widely expected that perinatal mental health is being negatively affected during the present COVID-19 pandemic. Methods: A review of studies that reported a measurement tool to assess perinatal mental health outcomes during the COVID-19 pandemic was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, CINAHL, and Google Scholar were used to search for peer-reviewed studies published after late 2019, in accordance with the emergence of the virus. The search resulted in the inclusion of ten studies. Approach to measure health outcome: The main approach to measure perinatal mental illness is the use of self-administered, validated questionnaires, usually in the clinical setting. Summary: Widespread use of these tools has afforded the clinical and research communities the ability to identify and support women who may be suffering from mental illness disorders during a pandemic. More research is needed to validate tools in other vulnerable, perinatal populations.Keywords: mental health during covid, perinatal mental health, perinatal mental health measurement tools, perinatal mental health tools
Procedia PDF Downloads 142994 Weak Electric Fields Enhance Growth and Nutritional Quality of Kale
Authors: So-Ra Lee, Myung-Min Oh
Abstract:
Generally, plants growing on the earth are under the influence of natural electric fields and may even require exposure of the electric field to survive. Electric signals have been observed within plants and seem to play an important role on various metabolic processes, but their role is not fully understood. In this study, we attempted to explore the response of plants under external electric fields in kale (Brassica oleracea var. acephala). The plants were hydroponically grown for 28 days in a plant factory. Electric currents at 10, 50 and 100 mA were supplied to nutrient solution for 3 weeks. Additionally, some of the plants were cultivated in a Faraday cage to remove the natural electric field. Kale plants exposed to electric fields had higher fresh weight than the control and plants in Faraday cage. Absence of electric field caused a significant decrease in shoot dry weight and root growth. Leaf area also showed a similar response with shoot fresh weight. Supplying weak electric stimulation enhanced nutritional quality including total phenolic content and antioxidant capacity. This work provides basic information on the effects of electric fields on plants and is a meaningful attempt for developing a new economical technology to increase crop productivity and quality by applying an electric field. This work was supported by Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries (IPET) through Agriculture, Food and Rural Affairs Research Center Support Program, funded by Ministry of Agriculture, Food and Rural Affairs (MAFRA) (717001-07-02-HD240).Keywords: electroculture, electric signal, faraday cage, electric field
Procedia PDF Downloads 296993 Oi̇l Absorption Behavior and Its Effect on Charpy Impact Test of Glass Reinforced Polyester Composites Used in the Manufacture of Naval Ship Hulls
Authors: Bouhafara Djaber, Menail Younes, Mesrafet Farouk, Aissaoui Mohammed Islem
Abstract:
This article presents results of experimental investigations of the durability of (GFRP) composite exposed to typical environments of marine industries applications,The use of fiber-glass reinforced polyester composites in marine applications such as Hulls of voyage boats and hulls of small vessels for the military navy , this type of composite is becoming attractive because of their reduced weight and improved corrosion resistance. However,a deep understating of oil ageing effect on composite structures is essential to ensure long-term performance and durability. in this work evaluate the effect of oil ageing on absorptıon behavıor and ımpact properties of glass/polyester composites manufactured with two types of fiber fabrics (fibreglass mat and fiberglass woven roving) and isophthalic polyester resin. The specimens obtained from commercial (GFRP) profiles made of unsaturated polyester resin were subjected to immersion in (i) marine oil for boats and (ii) salt water at ambient temperature for up to 1 month. The effects of such exposure conditions on this types of profile we analysed in what concerns their (i) mass change,(ii) mechanical response in impact, namely on the mechanical response – oil immersion caused a higher level of degradation, compared with salt water immersion;fracture surface examination by scanning electron microscopy revealed delamination, fiber debonding and resin crumbling due to oil effect.Keywords: Marine Engine Oil, Absorption, Polyester, Glass Fibre
Procedia PDF Downloads 86992 Vineyard Soils of Karnataka - Characterization, Classification and Soil Site Suitability Evaluation
Authors: Harsha B. R., K. S. Anil Kumar
Abstract:
Land characterization, classification, and soil suitability evaluation of grapes-growing pedons were assessed at fifteen taluks covering four agro climatic zones of Karnataka. Study on problems and potentials of grapes cultivation in selected agro-climatic zones was carried out along with the plant sample analysis. Twenty soil profiles were excavated as study site based on the dominance of area falling under grapes production and existing spatial variability of soils. The detailed information of profiles and horizon wise soil samples were collected to study the morphological, physical, chemical, and fertility characteristics. Climatic analysis and water retention characteristics of soils of major grapes-growing areas were also done. Based on the characterisation and classification study, it was revealed that soils of Doddaballapur (Bangalore Blue and Wine grapes), Bangalore North (GKVK Farm, Rajankunte, and IIHR Farm), Devanahalli, Magadi, Hoskote, Chikkaballapur (Dilkush and Red globe), Yelaburga, Hagari Bommanahalli, Bagalkot (UHS farm) and Indi fall under the soil order Alfisol. Vijaypur pedon of northern dry zone was keyed out as Vertisols whereas, Jamkhandi and Athani as Inceptisols. Properties of Aridisols were observed in B. Bagewadi (Manikchaman and Thompson Seedless) and Afzalpur. Soil fertility status and its mapping using GIS technique revealed that all the nutrients were found to be in adequate range except nitrogen, potassium, zinc, iron, and boron, which indicated the need for application along with organic matter to improve the SOC status. Varieties differed among themselves in yield and plant nutrient composition depending on their age, climatic, soil, and management requirements. Bangalore North (GKVK farm) and Jamkhandi are having medium soil organic carbon stocks of 6.21 and 6.55 kg m⁻³, respectively. Soils of Bangalore North (Rajankunte) were highly suitable (S1) for grapes cultivation. Under northern Karnataka, Vijayapura, B. Bagewadi, Indi, and Afzalpur vineyards were good performers despite the limitations of fertility and free lime content.Keywords: land characterization, suitability, soil orders, soil organic carbon stock
Procedia PDF Downloads 116991 Student's Difficulties with Classes That Involve Laboratory Education Approach
Authors: Kayondoamunmose Kamafrika
Abstract:
Experimental based Engineering education approach plays a vital role in the development of student’s deep understanding of both social and physical sciences. Experimental based education approach through laboratory class activities prepare students to meet national demand for high-tech skilled individuals in the government and private sector. However, students across the country are faced with difficulties in classes that involve laboratory activities: poor experimental based exposure in their early development of student’s education-life-cycle, lack of student engagement in scientific method practical thinking approach, lack of communication between students and the instructor during class, a large number of students in one classroom, lack of instruments and improper equipment calibration. The purpose of this paper is to help students develop their own scientific knowledge and understanding, develop their methodologies in the design of experiments, collect and analyze data, write laboratory reports, present and explain their findings. Experimental based laboratory activities allow students to learn with high-level understanding as well as engage in the design processes of constructing knowledge through practical means of doing science. Experimental based education systems approach will act as a catalyst in the development of practical-based-educational methodologies in social and physical science and engineering domain of learning; thereby, converting laboratory classes into pilot industries and students into professional experts in finding a solution for complex problems, research, and development of super high- tech systems.Keywords: experimental, engineering, innovation, practicability
Procedia PDF Downloads 197990 A Review of Protocols and Guidelines Addressing the Exposure of Occupants to Electromagnetic Field (EMF) Radiation in Buildings
Authors: Shabnam Monadizadeh, Charles Kibert, Jiaxuan Li, Janghoon Woo, Ashish Asutosh, Samira Roostaei, Maryam Kouhirostami
Abstract:
A significant share of the technology that has emerged over the past several decades produces electromagnetic field (EMF) radiation. Communications devices, household appliances, industrial equipment, and medical devices all produce EMF radiation with a variety of frequencies, strengths, and ranges. Some EMF radiation, such as Extremely Low Frequency (ELF), Radio Frequency (RF), and the ionizing range have been shown to have harmful effects on human health. Depending on the frequency and strength of the radiation, EMF radiation can have health effects at the cellular level as well as at brain, nervous, and cardiovascular levels. Health authorities have enacted regulations locally and globally to set critical values to limit the adverse effects of EMF radiation. By introducing a more comprehensive field of EMF radiation study and practice, architects and designers can design for a safer electromagnetic (EM) indoor environment, and, as building and construction specialists, will be able to monitor and reduce EM radiation. This paper identifies the nature of EMF radiation in the built environment, the various EMF radiation sources, and its human health effects. It addresses European and US regulations for EMF radiation in buildings and provides a preliminary action plan. The challenges of developing measurement protocols for the various EMF radiation frequency ranges and determining the effects of EMF radiation on building occupants are discussed. This paper argues that a mature method for measuring EMF radiation in building environments and linking these measurements to human health impacts occupant health should be developed to provide adequate safeguards for human occupants of buildings for future research.Keywords: biological affection, electromagnetic field, building regulation, human health, healthy building, clean construction
Procedia PDF Downloads 188989 A Comparative Time-Series Analysis and Deep Learning Projection of Innate Radon Gas Risk in Canadian and Swedish Residential Buildings
Authors: Selim M. Khan, Dustin D. Pearson, Tryggve Rönnqvist, Markus E. Nielsen, Joshua M. Taron, Aaron A. Goodarzi
Abstract:
Accumulation of radioactive radon gas in indoor air poses a serious risk to human health by increasing the lifetime risk of lung cancer and is classified by IARC as a category one carcinogen. Radon exposure risks are a function of geologic, geographic, design, and human behavioural variables and can change over time. Using time series and deep machine learning modelling, we analyzed long-term radon test outcomes as a function of building metrics from 25,489 Canadian and 38,596 Swedish residential properties constructed between 1945 to 2020. While Canadian and Swedish properties built between 1970 and 1980 are comparable (96–103 Bq/m³), innate radon risks subsequently diverge, rising in Canada and falling in Sweden such that 21st Century Canadian houses show 467% greater average radon (131 Bq/m³) relative to Swedish equivalents (28 Bq/m³). These trends are consistent across housing types and regions within each country. The introduction of energy efficiency measures within Canadian and Swedish building codes coincided with opposing radon level trajectories in each nation. Deep machine learning modelling predicts that, without intervention, average Canadian residential radon levels will increase to 176 Bq/m³ by 2050, emphasizing the importance and urgency of future building code intervention to achieve systemic radon reduction in Canada.Keywords: radon health risk, time-series, deep machine learning, lung cancer, Canada, Sweden
Procedia PDF Downloads 89988 Mercury Contamination of Wetland Caused by Wastewater from Chlor-Alkali Industry
Authors: Mitsuo Yoshida
Abstract:
A significant mercury contamination of soil/sediment was unveiled by an environmental monitoring program in a wetland along La Plata River, west to Montevideo City, Uruguay. The mercury contamination was caused by industrial wastewater discharged from a chlor-alkali plant using a mercury-cell process. The contamination level is above 60 mg/kg in soil/sediment. Most of mercury (Hg) in the environment is inorganic, but some fractions are converted by bacteria to methylmercury (MeHg), a toxic organic compound. MeHg biologically accumulates through a food-chain and become serious public health risk. In order to clarify the contaminated part for countermeasure operation, an intervention value of mercury contamination of sediment/soil was defined as 15 mg/kg (total Hg) by the authority. According to the intervention value, mercury contaminated area in the La Plata site is approximately 48,280 m² and estimated total volume of contaminated sediments/soils was around 18,750 m³. The countermeasures to contaminated zone were proposed in two stages; (i) mitigation of risks for public health and (ii) site remediation. The first stage is an installation of fens and net around the contamination zone, for mitigating risks of exposure, inhalation, and intake. The food chain among wetland-river ecosystem was also interrupted by the installation of net and fens. The state of mercury contamination in La Plata site and plan of countermeasure was disclosed to local people and the public, and consensus on setting off-limit area was successfully achieved. Mass media also contribute to share the information on the contamination site. The cost for countermeasures was borne by the industry under the polluter-pay-principle.Keywords: chlor-alkali plant, mercury contamination, polluter pay principle, Uruguay, wetland
Procedia PDF Downloads 144987 Fabrication of Nanoengineered Radiation Shielding Multifunctional Polymeric Sandwich Composites
Authors: Nasim Abuali Galehdari, Venkat Mani, Ajit D. Kelkar
Abstract:
Space Radiation has become one of the major factors in successful long duration space exploration. Exposure to space radiation not only can affect the health of astronauts but also can disrupt or damage materials and electronics. Hazards to materials include degradation of properties, such as, modulus, strength, or glass transition temperature. Electronics may experience single event effects, gate rupture, burnout of field effect transistors and noise. Presently aluminum is the major component in most of the space structures due to its lightweight and good structural properties. However, aluminum is ineffective at blocking space radiation. Therefore, most of the past research involved studying at polymers which contain large amounts of hydrogen. Again, these materials are not structural materials and would require large amounts of material to achieve the structural properties needed. One of the materials to alleviate this problem is polymeric composite materials, which has good structural properties and use polymers that contained large amounts of hydrogen. This paper presents steps involved in fabrication of multi-functional hybrid sandwich panels that can provide beneficial radiation shielding as well as structural strength. Multifunctional hybrid sandwich panels were manufactured using vacuum assisted resin transfer molding process and were subjected to radiation treatment. Study indicates that various nanoparticles including Boron Nano powder, Boron Carbide and Gadolinium nanoparticles can be successfully used to block the space radiation without sacrificing the structural integrity.Keywords: multi-functional, polymer composites, radiation shielding, sandwich composites
Procedia PDF Downloads 290986 Continuous-Time Convertible Lease Pricing and Firm Value
Authors: Ons Triki, Fathi Abid
Abstract:
Along with the increase in the use of leasing contracts in corporate finance, multiple studies aim to model the credit risk of the lease in order to cover the losses of the lessor of the asset if the lessee goes bankrupt. In the current research paper, a convertible lease contract is elaborated in a continuous time stochastic universe aiming to ensure the financial stability of the firm and quickly recover the losses of the counterparties to the lease in case of default. This work examines the term structure of the lease rates taking into account the credit default risk and the capital structure of the firm. The interaction between the lessee's capital structure and the equilibrium lease rate has been assessed by applying the competitive lease market argument developed by Grenadier (1996) and the endogenous structural default model set forward by Leland and Toft (1996). The cumulative probability of default was calculated by referring to Leland and Toft (1996) and Yildirim and Huan (2006). Additionally, the link between lessee credit risk and lease rate was addressed so as to explore the impact of convertible lease financing on the term structure of the lease rate, the optimal leverage ratio, the cumulative default probability, and the optimal firm value by applying an endogenous conversion threshold. The numerical analysis is suggestive that the duration structure of lease rates increases with the increase in the degree of the market price of risk. The maximal value of the firm decreases with the effect of the optimal leverage ratio. The results are indicative that the cumulative probability of default increases with the maturity of the lease contract if the volatility of the asset service flows is significant. Introducing the convertible lease contract will increase the optimal value of the firm as a function of asset volatility for a high initial service flow level and a conversion ratio close to 1.Keywords: convertible lease contract, lease rate, credit-risk, capital structure, default probability
Procedia PDF Downloads 103985 Selection Criteria in the Spanish Secondary Education Content and Language Integrated Learning (CLIL) Programmes and Their Effect on Code-Switching in CLIL Methodology
Authors: Dembele Dembele, Philippe
Abstract:
Several Second Language Acquisition (SLA) studies have stressed the benefits of Content and Language Integrated Learning (CLIL) and shown how CLIL students outperformed their non-CLIL counterparts in many L2 skills. However, numerous experimental CLIL programs seem to have mainly targeted above-average and rather highly motivated language learners. The need to understand the impact of the student’s language proficiency on code-switching in CLIL instruction motivated this study. Therefore, determining the implications of the students’ low-language proficiency for CLIL methodology, as well as the frequency with which CLIL teachers use the main pedagogical functions of code-switching, seemed crucial for a Spanish CLIL instruction on a large scale. In the mixed-method approach adopted, ten face-to-face interviews were conducted in nine Valencian public secondary education schools, while over 30 CLIL teachers also contributed with their experience in two online survey questionnaires. The results showed the crucial role language proficiency plays in the Valencian CLIL/Plurilingual selection criteria. The presence of a substantial number of low-language proficient students in CLIL groups, which in turn implied important methodological consequences, was another finding of the study. Indeed, though the pedagogical use of L1 was confirmed as an extended practice among CLIL teachers, more than half of the participants perceived that code-switching impaired attaining their CLIL lesson objectives. Therein, the dissertation highlights the need for more extensive empirical research on how code-switching could prove beneficial in CLIL instruction involving low-language proficient students while maintaining the maximum possible exposure to the target language.Keywords: CLIL methodology, low language proficiency, code switching, selection criteria, code-switching functions
Procedia PDF Downloads 86984 Real Time Detection of Application Layer DDos Attack Using Log Based Collaborative Intrusion Detection System
Authors: Farheen Tabassum, Shoab Ahmed Khan
Abstract:
The brutality of attacks on networks and decisive infrastructures are on the climb over recent years and appears to continue to do so. Distributed Denial of service attack is the most prevalent and easy attack on the availability of a service due to the easy availability of large botnet computers at cheap price and the general lack of protection against these attacks. Application layer DDoS attack is DDoS attack that is targeted on wed server, application server or database server. These types of attacks are much more sophisticated and challenging as they get around most conventional network security devices because attack traffic often impersonate normal traffic and cannot be recognized by network layer anomalies. Conventional techniques of single-hosted security systems are becoming gradually less effective in the face of such complicated and synchronized multi-front attacks. In order to protect from such attacks and intrusion, corporation among all network devices is essential. To overcome this issue, a collaborative intrusion detection system (CIDS) is proposed in which multiple network devices share valuable information to identify attacks, as a single device might not be capable to sense any malevolent action on its own. So it helps us to take decision after analyzing the information collected from different sources. This novel attack detection technique helps to detect seemingly benign packets that target the availability of the critical infrastructure, and the proposed solution methodology shall enable the incident response teams to detect and react to DDoS attacks at the earliest stage to ensure that the uptime of the service remain unaffected. Experimental evaluation shows that the proposed collaborative detection approach is much more effective and efficient than the previous approaches.Keywords: Distributed Denial-of-Service (DDoS), Collaborative Intrusion Detection System (CIDS), Slowloris, OSSIM (Open Source Security Information Management tool), OSSEC HIDS
Procedia PDF Downloads 357983 Development of Alpha Spectroscopy Method with Solid State Nuclear Track Detector Using Aluminium Thin Films
Authors: Nidal Dwaikat
Abstract:
This work presents the development of alpha spectroscopy method with Solid-state nuclear track detectors using aluminum thin films. The resolution of this method is high, and it is able to discriminate between alpha particles at different incident energy. It can measure the exact number of alpha particles at specific energy without needing a calibration of alpha track diameter versus alpha energy. This method was tested by using Cf-252 alpha standard source at energies 5.11 Mev, 3.86 MeV and 2.7 MeV, which produced by the variation of detector -standard source distance. On front side, two detectors were covered with two Aluminum thin films and the third detector was kept uncovered. The thickness of Aluminum thin films was selected carefully (using SRIM 2013) such that one of the films will block the lower two alpha particles (3.86 MeV and 2.7 MeV) and the alpha particles at higher energy (5.11 Mev) can penetrate the film and reach the detector’s surface. The second thin film will block alpha particles at lower energy of 2.7 MeV and allow alpha particles at higher two energies (5.11 Mev and 3.86 MeV) to penetrate and produce tracks. For uncovered detector, alpha particles at three different energies can produce tracks on it. For quality assurance and accuracy, the detectors were mounted on thick enough copper substrates to block exposure from the backside. The tracks on the first detector are due to alpha particles at energy of 5.11 MeV. The difference between the tracks number on the first detector and the tracks number on the second detector is due to alpha particles at energy of 3.8 MeV. Finally, by subtracting the tracks number on the second detector from the tracks number on the third detector (uncovered), we can find the tracks number due to alpha particles at energy 2.7 MeV. After knowing the efficiency calibration factor, we can exactly calculate the activity of standard source.Keywords: aluminium thin film, alpha particles, copper substrate, CR-39 detector
Procedia PDF Downloads 369982 A Framework for an Automated Decision Support System for Selecting Safety-Conscious Contractors
Authors: Rawan A. Abdelrazeq, Ahmed M. Khalafallah, Nabil A. Kartam
Abstract:
Selection of competent contractors for construction projects is usually accomplished through competitive bidding or negotiated contracting in which the contract bid price is the basic criterion for selection. The evaluation of contractor’s safety performance is still not a typical criterion in the selection process, despite the existence of various safety prequalification procedures. There is a critical need for practical and automated systems that enable owners and decision makers to evaluate contractor safety performance, among other important contractor selection criteria. These systems should ultimately favor safety-conscious contractors to be selected by the virtue of their past good safety records and current safety programs. This paper presents an exploratory sequential mixed-methods approach to develop a framework for an automated decision support system that evaluates contractor safety performance based on a multitude of indicators and metrics that have been identified through a comprehensive review of construction safety research, and a survey distributed to domain experts. The framework is developed in three phases: (1) determining the indicators that depict contractor current and past safety performance; (2) soliciting input from construction safety experts regarding the identified indicators, their metrics, and relative significance; and (3) designing a decision support system using relational database models to integrate the identified indicators and metrics into a system that assesses and rates the safety performance of contractors. The proposed automated system is expected to hold several advantages including: (1) reducing the likelihood of selecting contractors with poor safety records; (2) enhancing the odds of completing the project safely; and (3) encouraging contractors to exert more efforts to improve their safety performance and practices in order to increase their bid winning opportunities which can lead to significant safety improvements in the construction industry. This should prove useful to decision makers and researchers, alike, and should help improve the safety record of the construction industry.Keywords: construction safety, contractor selection, decision support system, relational database
Procedia PDF Downloads 284981 The Social Impact of Green Buildings
Authors: Elise Machline
Abstract:
Policy instruments have been developed worldwide to reduce the energy demand of buildings. Two types of such instruments have been green building rating systems and energy efficiency standards for buildings -such as Green Star (Australia), LEED (United States, Leadership in Energy and Environmental Design), Energy Star (United States), and BREEAM (United Kingdom, Building Research Establishment Environmental Assessment Method). The popularity of the idea of sustainable development has allowed the actors to consider the potential value generated by the environmental performance of buildings, labeled “green value” in the literature. Sustainable performances of buildings are expected to improve their attractiveness, increasing their value. A growing number of empirical studies demonstrate that green buildings yield rental/sale premia, as well as higher occupancy rates and thus higher asset values. The results suggest that green buildings are not affordable to all and that their construction tends to have a gentrifying effect. An increasing number of countries are institutionalizing green strategies for affordable housing. In that sense, making green buildings affordable to all will depend on government policies. That research aims to investigate whether green building fosters inequality in Israel, under the banner of sustainability. The method is comparison (of the market value). This method involves comparing the green buildings sale prices with non-certified buildings of the same type that have undergone recent transactions. The “market value” is deduced from those sources by analogy. The results show that, in Israel, green building projects are usually addressed to the middle to upper classes. The green apartment’s sale premium is about 19% (comparing to non-certified dwelling). There is a link between energy and/or environmental performance and the financial value of the dwellings. Moreover, price differential is much higher than the value of energy savings. This perpetuates socio-spatial and socio-economic inequality as well as ecological vulnerability for the poor and other socially marginal groups. Moreover, there are no green affordable housings and the authorities do not subsidy green building or retrofitting.Keywords: green building, gentrification, social housing, green value, green building certification
Procedia PDF Downloads 422980 Laser Powder Bed Fusion Awareness for Engineering Students in France and Qatar
Authors: Hiba Naccache, Rima Hleiss
Abstract:
Additive manufacturing AM or 3D printing is one of the pillars of Industry 4.0. Compared to traditional manufacturing, AM provides a prototype before production in order to optimize the design and avoid the stock market and uses strictly necessary material which can be recyclable, for the benefit of leaning towards local production, saving money, time and resources. Different types of AM exist and it has a broad range of applications across several industries like aerospace, automotive, medicine, education and else. The Laser Powder Bed Fusion (LPBF) is a metal AM technique that uses a laser to liquefy metal powder, layer by layer, to build a three-dimensional (3D) object. In industry 4.0 and aligned with the numbers 9 (Industry, Innovation and Infrastructure) and 12 (Responsible Production and Consumption) of the Sustainable Development Goals of the UNESCO 2030 Agenda, the AM’s manufacturers committed to minimizing the environmental impact by being sustainable in every production. The LPBF has several environmental advantages, like reduced waste production, lower energy consumption, and greater flexibility in creating components with lightweight and complex geometries. However, LPBF also have environmental drawbacks, like energy consumption, gas consumption and emissions. It is critical to recognize the environmental impacts of LPBF in order to mitigate them. To increase awareness and promote sustainable practices regarding LPBF, the researchers use the Elaboration Likelihood Model (ELM) theory where people from multiple universities in France and Qatar process information in two ways: peripherally and centrally. The peripheral campaigns use superficial cues to get attention, and the central campaigns provide clear and concise information. The authors created a seminar including a video showing LPBF production and a website with educational resources. The data is collected using questionnaire to test attitude about the public awareness before and after the seminar. The results reflected a great shift on the awareness toward LPBF and its impact on the environment. With no presence of similar research, to our best knowledge, this study will add to the literature on the sustainability of the LPBF production technique.Keywords: additive manufacturing, laser powder bed fusion, elaboration likelihood model theory, sustainable development goals, education-awareness, France, Qatar, specific energy consumption, environmental impact, lightweight components
Procedia PDF Downloads 95979 Records of Lepidopteron Borers (Lepidoptera) on Stored Seeds of Indian Himalayan Conifers
Authors: Pawan Kumar, Pitamber Singh Negi
Abstract:
Many of the regeneration failures in conifers are often being attributed to heavy insect attack and pathogens during the period of seed formation and under storage conditions. Conifer berries and seed insects occur throughout the known range of the hosts and also limit the production of seed for nursery stock. On occasion, even entire seed crops are lost due to insect attacks. The berry and seeds of both the species have been found to be infected with insects. Recently, heavy damage to the berry and seeds of Juniper and Chilgoza Pine was observed in the field as well as in stored conditions, leading to reduction in the viability of seeds to germinate. Both the species are under great threat and regeneration of the species is very low. Due to lack of adequate literature, the study on the damage potential of seed insects was urgently required to know the exact status of the insect-pests attacking seeds/berries of both the pine species so as to develop pest management practices against the insect pests attack. As both the species are also under threat and are fighting for survival, so the study is important to develop management practices for the insect-pests of seeds/berries of Juniper and Chilgoza pine so as to evaluate in the nursery, as these species form major vegetation of their distribution zones. A six-year study on the management of insect pests of seeds of Chilgoza revealed that seeds of this species are prone to insect pests mainly borers. During present investigations, it was recorded that cones of are heavily attacked only by Dioryctria abietella (Lepidoptera: Pyralidae) in natural conditions, but seeds which are economically important are heavily infected, (sometimes up to 100% damage was also recorded) by insect borer, Plodia interpunctella (Lepidoptera: Pyralidae) and is recorded for the first time ‘to author’s best knowledge’ infesting the stored Chilgoza seeds. Similarly, Juniper berries and seeds were heavily attacked only by a single borer, Homaloxestis cholopis (Lepidoptera: Lecithoceridae) recorded as a new report in natural habitat as well as in stored conditions. During the present investigation details of insect pest attack on Juniper and Chilgoza pine seeds and berries was observed and suitable management practices were also developed to contain the insect-pests attack.Keywords: borer, chilgozapine, cones, conifer, Lepidoptera, juniper, management, seed
Procedia PDF Downloads 151978 A National Survey of Clinical Psychology Graduate Student Attitudes toward Psychotherapy Treatment Manuals: A Replication Study
Authors: B. Bergström, A. Ladd, A. Jones, L. Rosso, P. Michael
Abstract:
Attitudes toward treatment manuals serve as a meaningful predictor of general attitudes toward evidence-based practice. Despite demonstrating high effectiveness in treating many mental disorders, manualized treatments have been underutilized by practitioners. Thus, one can assess the state of the field regarding the adoption of evidence-based practices by surveying practitioner attitudes towards manualized treatments. This study is an adapted replication that assesses psychology graduate student attitudes towards manualized treatments, as a general marker for attitudes towards evidence-based practice. Training programs provide future clinicians with the foundation for critical skills in clinical practice. Research demonstrates that post-graduate continuing education has little to no effect on clinical practice; thus, graduate programs serve as the primary, and often final platform for all future practice. However, there are little empirical data identifying the attitudes and training of graduate students in utilizing manualized treatments. The empirical analysis of this study indicates an increase in positive attitudes among graduate student attitudes towards manualized treatments (within the United States), when compared to past surveys of professional psychologists. Findings from this study may inform graduate programs of barriers for students in developing positive attitudes toward manualized treatments and evidence-based practice. This study also serves as a preliminary predictor of the state-of-the field, in regards to professional psychologists attitudes towards evidence-based practice, if attitudes remain stable. This study indicates that the attitudes toward utilizing evidence-based practices, such as treatment manuals, has become more positive since year 2000.Keywords: exposure therapy, evidence based practice, manualized treatments, student attitudes
Procedia PDF Downloads 166977 Visual Intelligence: Perception, Image and Manipulation in Visual Communication
Authors: Poojitha Vemula
Abstract:
Understanding how we use image manipulation to communicate through an audience’s perceptions and conceive visual intelligence. With the use of many software and high-end skills, designers have developed a third eye to combine two different visuals and create the desired image by using photoshop and other software skills. The purpose of visual intelligence is to convey a message to the targeted audience. For instance, the images of models are retouched on their skin to make it more convincing and draw attention from the audience. There are many ways of manipulating an image, such as double exposure, retouching photography inks or paint airbrushing and piecing photos together, or enhancing the brightness and contrast. To understand visual intelligence, a questionnaire survey as well as research was conducted on how image manipulation is used by both the audience and the designers. This depends on the message that needs to be conveyed by the brands. For instance, Fair & Lovely, a brightening cream for ladies use a lot of retouching and effects to show the dramatic change the cream takes effect on dark or dusky faces. Thus the designer’s role is to use their third eye to incorporate the message into visuals. The research and questionnaire survey concludes the perceptions and manipulations used in visual communication. However this is all to make an effortless communication between the designer and the audience by using the skills of the designer and the features provided by the software. The objective of visual intelligence is to covet the message of the brands that advertise their products or services by using visuals through softwares. Conveying a message through visual intelligence requires an audiences perceptions and understanding from the visuals created by the artists or designers. Visual intelligence determines how we use our technical skills to retouch and manipulate an image for a better understanding to convey the message to the targeted audience. This also bridges the communication between the brand and the audience.Keywords: graphic design, visual communication, convey messages, photoshop, image manipulation
Procedia PDF Downloads 232976 Gethuk Marillo: The New Product Development of Anti-Cancer Snacks Utilizing Xanthones and Anthocyanin in Mangosteen Pericarp and Tamarillo Fruit
Authors: Desi Meriyanti, Delina Puspa Rosana Firdaus, Ristia Rinati
Abstract:
Nowadays, the presence of free radicals become a big concern due to its negative impact to the body, which can triggers the formation of degenerative diseases such as cancer, heart disease cardiovascular, diabetic mellitus and others. Free radical oxidation can be prevented by the presence of antioxidants. Naturally, the human body produces its own antioxidants. Because of the free radicals exposure are so intense, especially from the environment, it is necessary to supply antioxidants needed from outside, through the consumption of functional foods with high antioxidant content. Gethuk is one of the traditional snacks in Indonesia. Gethuk is made from cassava with minimal processing such as boiling, destructing, and forming. Gethuk is classified as a familiar snack in the community, so it has a potential for developing, especially into a functional food. The low content of antioxidants in gethuk can be overcome with the development of a product called Gethuk Marillo. Gethuk Marillo is gethuk with the addition of natural antioxidants from mangosteen pericarp extract which has a high content of xanthones, these compounds are classified into flavonoids and act as antioxidants in the body. Gethuk Marillo served along with tamarillo fruit sauce which is also high in antioxidants such as anthocyanin. The combination between 300 grams gethuk Marillo and sauce contain flavonoid about 31% of human antioxidant needs per day. Gethuk Marillo called as a functional food because of high flavonoids content which can prevent degenerative diseases namely cancer, as many studies that the xanthone and anthocyanins compounds can effectively prevent the formation of cancer cells in human body.Keywords: Gethuk marillo, xanthones, anthocyanin, high antioxidants, anti-cancer
Procedia PDF Downloads 660975 Evaluation of Alternative Energy Sources for Energy Production in Turkey
Authors: Naci Büyükkaracığan, Murat Ahmet Ökmen
Abstract:
In parallel with the population growth rate, the need of human being for energy sources in the world is gradually increasing incessant. The addition of this situation that demand for energy will be busier in the future, industrialization, the rise in living standards and technological developments, especially in developing countries. Alternative energy sources have aroused interest due to reasons such as serious environmental issues that were caused by fossil energy sources, potentially decreasing reserves, different social, political and economic problems caused by dependency on source providing countries and price instability. Especially in developed countries as European countries and also U.S.A particularly, alternative energy sources such as wind, geothermal, solar and biomass energy, hydrolic and hydrogen have been utilized in different forms, especially in electricity production. It includes a review of technical and environmental factors for energy sources that are potential replacements for fossil fuels and examines their fitness to supply the energy for a high standard of living on a worldwide basis. Despite all developments, fossil energy sources have been overwhelmingly used all around the world in primary energy sources consumption and they will outnumber other energy sources in the short term. Today, parallel to population growth and economy in Turkey, energy sources consumption is increasingly continuing. On one side, Turkey, currently 80% dependent on energy providing countries, has been heavily conducting fossil energy sources raw material quest within its own borders in order to lower the percentage, and the other side, there have been many researches for exploring potential of alternative energy sources and utilization. This case will lead to both a decrease in foreign energy dependency and a variety of energy sources. This study showed the current energy potential of Turkey and presents historical development of these energy sources and their share in electricity production. The research also seeked for answers to arguments that if the potential can be sufficient in the future. As a result of this study, it was concluded that observed geothermal energy, particularly active tectonic regions of Turkey, to have an alternative energy potential could be considered to be valuable on bass wind and solar energy.Keywords: alternative energy sources, energy productions, hydroenergy, solar energy, wind energy
Procedia PDF Downloads 633974 Beyond Typical Textbooks: Adapting Authentic Materials for Engaged Learning in the ELT Classroom
Authors: Fatemeh Miraki
Abstract:
The use of authentic materials in English Language Teaching (ELT) has become increasingly prominent as educators recognize the value of exposing learners to real-world language use and cultural contexts. The integration of authentic materials in ELT aligns with the understanding that language learning is most effective when situated within authentic contexts (Richards & Rodgers, 2001). Tomlinson (1998) highlights the significance of authentic materials in ELT by research indicating that they offer learners exposure to genuine language use and cultural contexts. Tomlinson's work emphasizes the importance of creating meaningful learning experiences through the use of authentic materials. Research by Dörnyei (2001) underscores the potential of authentic materials to enhance students' intrinsic motivation through their relevance to real-life language use. The goal of this review paper is to explore the use of authentic materials in English Language Teaching (ELT) and its impact on language learning. It also discusses best practices for selecting and integrating such authentic materials into ELT curriculum, highlighting the benefits and challenges of using authentic materials to enhance student engagement, motivation, and language proficiency. Drawing on current research and practical examples, this paper provides insights into how teachers can effectively navigate the world of authentic materials to create dynamic and meaningful learning experiences for 21st century ELT learners. The findings of this study advocates for a shift towards embracing authentic materials within the ELT classroom, acknowledging their profound impact on language proficiency, intercultural competence, and learner engagement. It showed the transformative potential of authentic materials, educators can undergo a vibrant and immersive language learning experience, enriched with real-world application and cultural authenticity.Keywords: authentic materials, ELT Classroom, ELT curriculum, students’ engagement
Procedia PDF Downloads 62973 Evaluation of the Causes of Exposure to Mobbing of Employees in the Public Sector in Turkey
Authors: Taner Cindik, Ferya Tas Ciftci
Abstract:
Mobbing in the public sector and specific issues (i.e., the demand for non-pecuniary damages) regarding mobbing have become very important in the light of the precedents constituted by the Turkish Council of State in 2010. The legal scope of mobbing is not able to be determined since the concept of mobbing is not defined in Turkish law system. This study aims to reveal three major problems caused by the lack of laws related to mobbing in the Turkish legal system. First, the absence of an arrangement for disciplinary penalties leads that general provisions in the disciplinary law are implemented. This situation, therefore, causes difficulties in practice. Second, not being drawn of the lines in the topic concerning mobbing in public sector leads confusions in being direction of hostility. Third, the fact that there is a legal gap on seeking non-pecuniary compensation when employees in public sector are exposed to mobbing might make it difficult to obtain non-pecuniary compensation. Within the context of these major problems, civil servants in Turkey do not have enough protection mechanism. However, some possible legal arrangements will help civil servants to protect against mobbing. This study may be considered important because of the fact that mobbing in the public sector is at a significant level and has not been evaluated in this context before. This research is mainly a study of Turkish legal system and evaluates critically law case to determine legal problems. As a result of this study, three main problems might be identified because there is legal gap regarding mobbing in the public sector. In conclusion, the introduction of the major problems related to mobbing in this study might shed light on making the proper regulations of this subject in Turkish law system. In this respect, the plaintiff will be provided convenience in the point of non-pecuniary damages and this study will guide the assessment of legal liability of those who implement mobbing.Keywords: human rights violations, mobbing, public sector, direction of hostility, non-pecuniary compensation, disciplinary law
Procedia PDF Downloads 247972 Durability of Cement Bonded Particleboards Produced from Terminalia superba and Gmelina arborea against Subterranean Termite Attack
Authors: Amos Olajide Oluyege, Emmanuel Uchechukwu Opara, Sunday Adeniyi Adedutan, Joseph Adeola Fuwape
Abstract:
This study was conducted to determine the durability of wood-cement particleboards when exposed to attack by subterranean termites, Macrotermes subhylinus. The boards were made from Terminalia superba and Gmelina arborea wood sawdust at nominal board densities (BD) of 1000, 900, and 800 kg/m³ using wood-cement mixing ratios (MR) of 3:1, 2.5:1, 2:1, and 1:1. Above ground durability tests against termite attack were carried out according to ASTM D 2017 for 14 weeks. Results of visual assessment of the wood cement particleboards show that all the board samples had a visual rating that was not less than 7 (i.e., moderate attack) for both species irrespective of the MR and BD. T. superba boards were found to have higher resistance to termite attack compared to their G. arborea counterparts. The mean values for weight loss following exposure ranged from 1.93 to 6.13% and 3.24 to 12.44%. Analysis of variance (ANOVA) results of the weight loss assessment revealed a significant (p < 0.05) effect of species and mixing ratio on the weight loss of the boards due to termite attack with F(₁,₇₂) = 92.890 and P = 0.000 and F(₃,₇₂) = 8.318 and p = 0.000, while board density did not have any significant effect (p > 0.05) with F (₂,₇₂) = 1.307 and p = 0.277. Thus, boards made from a higher mixing ratio had better resistance against termite attacks. Thus, it can be concluded that the durability of cement-bonded particleboards when exposed to subterranean termite attack is not only dependent on the quality of the wood raw material (species) but also on the enhanced protection imparted by the cement matrix; the protection increased with increase in cement/wood mixing ratio.Keywords: cement-bonded particleboard, mixing ratio, board density, Gmelina arborea, Terminalia superba
Procedia PDF Downloads 221971 The Impact of Child Maltreatment on School Performance in Saudi Arabia
Authors: Al Muneef Maha, Al Tamimi Dana
Abstract:
Introduction: Child maltreatment was proven to negatively impact children’s and adolescent’s academic performances; showing less academic achievements, problems completing homework assignments, and was marginally associated with being frequently absent from school (1). Objectives: To identify the impact of child maltreatment on school performance among adolescents in National Guard Schools. Materials and Methods: The study was conducted at National Guard schools in Riyadh. Students aged 12-19 years were invited to participate. Participants (N=674) completed the survey instrument which included demographics, exposure to different types of abuse, and overall level of academic performance. Results: Participants’ mean age was 15.6±1.6 years and males (53%). Ninety-five percent lived with both parents, 2% with single parent, and 3% with step parents. Four percent lived with alcoholic parents or guardians, and 7% have lived with a family member who has been arrested or imprisoned. Poor performance (failure in exam) were more likely among the students who lived with alcoholics vs. non-alcoholics (33% vs. 11%, p<0.01), imprisoned family member vs. non-imprisoned (26% vs. 11%, p<0.01), psychologically abused vs. not abused (21% vs. 10%, p<0.01), physically abused vs. not abused (19% vs. 9%, p<0.01). Predisposing factors to poor performance in school included living with alcoholic parents or guardians (OR=2.8, CI=1.1-6.7), psychologically abused (OR=1.7, CI=1.0-3.0), and physically abused (OR=1.7, CI=1.0-2.8). Conclusions: The results suggest that child maltreatment may adversely impact school performance. These findings highlight the importance of increasing the awareness about the impact of child maltreatment on school performance among families, schools, and the community. Recommend to the Ministry of Education to consider counseling of students with poor performance due to adverse child experiences or maltreatment.Keywords: child abuse, child maltreatment, school performance, Saudi Arabia
Procedia PDF Downloads 328970 Field Evaluation of Concrete Using Hawaiian Aggregates for Alkali Silica Reaction
Authors: Ian N. Robertson
Abstract:
Alkali Silica Reaction (ASR) occurs in concrete when the alkali hydroxides (Na, K and OH) from the cement react with unstable silica, SiO2, in some types of aggregate. The gel that forms during this reaction will expand when it absorbs water, potentially leading to cracking and overall expansion of the concrete. ASR has resulted in accelerated deterioration of concrete highways, dams and other structures that are exposed to moisture during their service life. Concrete aggregates available in Hawaii have not demonstrated a history of ASR, however, accelerated laboratory tests using ASTM 1260 indicated a potential for ASR with some aggregates. Certain clients are now requiring import of aggregates from the US mainland at great expense. In order to assess the accuracy of the laboratory test results, a long-term field study of the potential for ASR in concretes made with Hawaiian aggregates was initiated in 2011 with funding from the US Federal Highway Administration and Hawaii Department of Transportation. Thirty concrete specimens were constructed of various concrete mixtures using aggregates from all Hawaiian aggregate sources, and some US mainland aggregates known to exhibit ASR expansion. The specimens are located in an open field site in Manoa valley on the Hawaiian Island of Oahu, exposed to relatively high humidity and frequent rainfall. A weather station at the site records the ambient conditions on a continual basis. After two years of monitoring, only one of the Hawaiian aggregates showed any sign of expansion. Ten additional specimens were fabricated with this aggregate to confirm the earlier observations. Admixtures known to mitigate ASR, such as fly ash and lithium, were included in some specimens to evaluate their effect on the concrete expansion. This paper describes the field evaluation program and presents the results for all forty specimens after four years of monitoring.Keywords: aggregate, alkali silica reaction, concrete durability, field exposure
Procedia PDF Downloads 251