Search results for: urban environment and model

Authors: Tourab Wafa, Nemamcha Mohamed, Babouri Abdessalem

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This paper consists on an experimental and analytical characterization of the electromagnetic environment in the in the medium surrounding a circuit of two 220 Kv power lines running in parallel. The analysis presented in this paper is divided into two main parts. The first part concerns the experimental study of the behavior of the electric field and magnetic field generated by the selected double-circuit at ground level (0 m). While the second part simulate and calculate the fields profiles generated by the both lines at different levels above the ground, from (0 m) to the level close to the lines conductors (20 m above the ground) using the electrostatic and magneto-static modules of the COMSOL multi-physics software. The implications of the results are discussed and compared with the ICNIRP reference levels for occupational and non occupational exposures.

Keywords: HV power lines, low frequency electromagnetic fields, electromagnetic compatibility, inductive and capacitive coupling, standards

Procedia PDF Downloads 467

Authors: Mahadzirah Mohamad, Nur Izzati Ab Ghani

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Worldwide, tourism sustained growth and remained to be one of the fast-growing sectors. Malaysia tourism industry experienced an unstable and declining pattern of international tourist arrival’s growth rate. The situation suggested that the industry was competitive and denoted the need to study factors that influence tourist loyalty. The primary purpose of this study was to develop a model that examined how destination image, perceived value, service quality and tourist satisfaction affect destination loyalty. The study was conducted at the Kuala Lumpur International Airport and Kota Kinabalu International Airport. The respondents were international tourists from United Kingdom and Australia and they were selected using simple random sampling method. A total of 337 respondents were subjected to data analysis using structural equation modelling. The study uncovered that perceived value and destination image was highly correlated and the model suggested that these constructs should be treated as one construct. The construct was labelled as overall destination image. Overall image had significant direct effect on service quality, satisfaction and loyalty. Service quality had a significant indirect effect on loyalty through satisfaction as a moderating variable. However, satisfaction had no mediating effect on the relationship between overall destination image and loyalty. The study suggested that more efforts should be focused on portraying the image of experiencing joy with many interesting natural scenic places to see whilst on a holiday to Malaysia. In addition, the destination management office should promote tourist visiting to Malaysia would enjoy quality service related to accommodation, information facilities, health, and shopping. Tourist satisfaction empirically proved to be an important construct that influenced destination loyalty. This study contributed to the extended knowledge that postulated overall image of a destination was measured by perceived value and destination image.

Keywords: destination image, destination loyalty, structural equation modelling, tourist satisfaction

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Authors: Ashneel Ajay Singh, Kazumi Sakuramoto, Naoki Suzuki, Kalla Alok, Nath Paras

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Bluefin (Thunnus orientalis) tuna is one of the most economically valuable tuna species in the world. In recent years the stock has been observed to decline. It is suspected that the stock-recruitment relationship and population structure is influenced by environmental and climatic variables. This study was aimed at investigating the influence of environmental and climatic conditions on the trajectory of the different life stages of the North Pacific bluefin tuna. Exploratory analysis was performed for the North Pacific sea surface temperature (SST) and Pacific Decadal Oscillation (PDO) on the time series of the bluefin tuna cohorts (age-0, 1, 2,…,9, 10+). General Additive Modeling (GAM) was used to reconstruct the recruitment (R) trajectory. The spatial movement of the SST was also monitored from 1953 to 2012 in the distribution area of the bluefin tuna. Exploratory analysis showed significance influence of the North Pacific Sea Surface temperature (SST) and Pacific Decadal Oscillation (PDO) on the time series of the age-0 group. Other age group (1, 2,…,9, 10+) time series did not exhibit any significant correlations. PDO showed most significant relationship in the months of October to December. Although the stock-recruitment relationship is of biological significance, the recruits (age-0) showed poor correlation with the Spawning Stock Biomass (SSB). Indeed the most significant model incorporated the SSB, SST and PDO. The results show that the stock-recruitment relationship of the North Pacific bluefin tuna is multi-dimensional and cannot be adequately explained by the SSB alone. SST and PDO forcing of the population structure is of significant importance and needs to be accounted for when making harvesting plans for bluefin tuna in the North Pacific.

Keywords: pacific bluefin tuna, Thunnus orientalis, cohorts, recruitment, spawning stock biomass, sea surface temperature, pacific decadal oscillation, general additive model

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Authors: Osman Zorbaz, Selen Demirtas-Zorbaz, Ozlem Ulas

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The factors that cause adolescents to drop out school were several. One of the frameworks about school dropout focuses on the contextual factors around the adolescents whereas the other one focuses on individual factors. It can be said that both factors are important equally. In this study, both adolescent’s individual factors (anti-social behaviors, academic success) and contextual factors (parent academic involvement, parent academic support, number of siblings, living with parent) were examined in the term of school dropout. The study sample consisted of 346 high school students in the public schools in Ankara who continued their education in 2015-2016 academic year. One hundred eighty-five the students (53.5%) were girls and 161 (46.5%) were boys. In addition to this 118 of them were in ninth grade, 122 of them in tenth grade and 106 of them were in eleventh grade. Multiple regression and one-way ANOVA statistical methods were used. First, it was examined if the data meet the assumptions and conditions that are required for regression analysis. After controlling the assumptions, regression analysis was conducted. Parent academic involvement, parent academic support, number of siblings, anti-social behaviors, academic success variables were taken into the regression model and it was seen that parent academic involvement (t=-3.023, p < .01), anti-social behaviors (t=7.038, p < .001), and academic success (t=-3.718, p < .001) predicted school dropout whereas parent academic support (t=-1.403, p > .05) and number of siblings (t=-1.908, p > .05) didn’t. The model explained 30% of the variance (R=.557, R2=.300, F5,345=30.626, p < .001). In addition to this the variance, results showed there was no significant difference on high school students school dropout levels according to living with parents or not (F2;345=1.183, p > .05). Results discussed in the light of the literature and suggestion were made. As a result, academic involvement, academic success and anti-social behaviors will be considered as an important factors for preventing school drop-out.

Keywords: adolescents, anti-social behavior, parent academic involvement, parent academic support, school dropout

Procedia PDF Downloads 269

Authors: Fong-Zuo Lee, Jihn-Sung Lai, Yung-Bin Lin, Xiaoqin Liu, Kuo-Chun Chang, Zhi-Xian Yang, Wen-Dar Guo, Jian-Hao Hong

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In recent years, climate change is a major factor to increase rainfall intensity and extreme rainfall frequency. The increased rainfall intensity and extreme rainfall frequency will increase the probability of flash flood with abundant sediment transport in a river basin. The floods caused by heavy rainfall may cause damages to the bridge, embankment, hydraulic works, and the other disasters. Therefore, the foundation scouring of bridge pier, embankment and spur dike caused by floods has been a severe problem in the worldwide. This severe problem has happened in many East Asian countries such as Taiwan and Japan because of these areas are suffered in typhoons, earthquakes, and flood events every year. Results from the complex interaction between fluid flow patterns caused by hydraulic works and the sediment transportation leading to the formation of river morphology, it is extremely difficult to develop a reliable and durable sensor to measure river bed degradation and bridge pier scouring. Therefore, an innovative scour monitoring sensor using vibration-based Micro-Electro Mechanical Systems (MEMS) was developed. This vibration-based MEMS sensor was packaged inside a stainless sphere with the proper protection of the full-filled resin, which can measure free vibration signals to detect scouring/deposition processes at the bridge pier. In addition, a friendly operational system includes rainfall runoff model, one-dimensional and two-dimensional numerical model, and the applicability of sediment transport equation and local scour formulas of bridge pier are included in this research. The friendly operational system carries out the simulation results of flood events that includes the elevation changes of river bed erosion near the specified bridge pier and the erosion depth around bridge piers. In addition, the system is developed with easy operation and integrated interface, the system can supplies users to calibrate and verify numerical model and display simulation results through the interface comparing to the scour monitoring sensors. To achieve the forecast of the erosion depth of river bed and main bridge pier in the study area, the system also connects the rainfall forecast data from Taiwan Typhoon and Flood Research Institute. The results can be provided available information for the management unit of river and bridge engineering in advance.

Keywords: flash flood, river bed degradation, bridge pier scouring, a friendly operational system

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Authors: Aymen Laadhari

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During the last decade, an increasing number of contributions have been made in the fields of scientific computing and numerical methodologies applied to the study of the hemodynamics in the heart. In contrast, the numerical aspects concerning the interaction of pulsatile blood flow with highly deformable thin leaflets have been much less explored. This coupled problem remains extremely challenging and numerical difficulties include e.g. the resolution of full Fluid-Structure Interaction problem with large deformations of extremely thin leaflets, substantial mesh deformations, high transvalvular pressure discontinuities, contact between leaflets. Although the Lagrangian description of the structural motion and strain measures is naturally used, many numerical complexities can arise when studying large deformations of thin structures. Eulerian approaches represent a promising alternative to readily model large deformations and handle contact issues. We present a fully Eulerian finite element methodology tailored for the simulation of pulsatile blood flow in the aorta and sinus of Valsalva interacting with highly deformable thin leaflets. Our method enables to use a fluid solver on a fixed mesh, whilst being able to easily model the mechanical properties of the valve. We introduce a semi-implicit time integration scheme based on a consistent NewtonRaphson linearization. A variant of the classical Newton method is introduced and guarantees a third-order convergence. High-fidelity computational geometries are built and simulations are performed under physiological conditions. We address in detail the main features of the proposed method, and we report several experiments with the aim of illustrating its accuracy and efficiency.

Keywords: eulerian, level set, newton, valve

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Authors: Ana Neves, John Leander, Ignacio Gonzalez, Raid Karoumi

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Systematic monitoring and inspection are needed to assess the present state of a structure and predict its future condition. If an irregularity is noticed, repair actions may take place and the adequate intervention will most probably reduce the future costs with maintenance, minimize downtime and increase safety by avoiding the failure of the structure as a whole or of one of its structural parts. For this to be possible decisions must be made at the right time, which implies using systems that can detect abnormalities in their early stage. In this sense, Structural Health Monitoring (SHM) is seen as an effective tool for improving the safety and reliability of infrastructures. This paper explores the decision-making problem in SHM regarding the maintenance of civil engineering structures. The aim is to assess the present condition of a bridge based exclusively on measurements using the suggested method in this paper, such that action is taken coherently with the information made available by the monitoring system. Artificial Neural Networks are trained and their ability to predict structural behavior is evaluated in the light of a case study where acceleration measurements are acquired from a bridge located in Stockholm, Sweden. This relatively old bridge is presently still in operation despite experiencing obvious problems already reported in previous inspections. The prediction errors provide a measure of the accuracy of the algorithm and are subjected to further investigation, which comprises concepts like clustering analysis and statistical hypothesis testing. These enable to interpret the obtained prediction errors, draw conclusions about the state of the structure and thus support decision making regarding its maintenance.

Keywords: artificial neural networks, clustering analysis, model-free damage detection, statistical hypothesis testing, structural health monitoring

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Authors: Mary Josephine Rani

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Virtually all metals are toxic to aquatic organisms because of the devastating effect of these metals on humans; heavy metals are one of the most toxic forms of aquatic pollution. Metal concentrations in aquatic organisms appear to be of several magnitudes higher than concentrations present in the ecosystem. Mercury is one of the most toxic heavy metals in the environment. The principal sources of contamination in wastewater are chloralkali plants, battery factories, mercury switches, and medical wastes. Elevated levels of mercury in aquatic organisms specially fish represent both an ecological and human concern. Amino acid levels were estimated in five tissues (gills, liver, kidney, brain and muscle) of Clariasbatrachus after 28 days of chronic exposure to mercury. Free amino acids serve as precursor for energy production under stress and for the synthesis of required proteins to face the metal challenge.

Keywords: amino acids, fish, mercury, toxicity

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Authors: Helen Pluut, Remus Ilies, Nikos Dimotakis, Maral Darouei

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This study aims to examine recovery from work as an important daily activity with implications for workplace behavior. Building on affective events theory and the stressor-detachment model as frameworks, this paper proposes and tests a comprehensive within-individual model that uncovers the role of recovery processes at home in linking workplace demands (e.g., workload) and stressors (e.g., workplace incivility) to next-day organizational citizenship behaviors (OCBs). Our sample consisted of 126 full-time employees in a large Midwestern University. For a period of 16 working days, these employees were asked to fill out 3 electronic surveys while at work. The first survey (sent out in the morning) measured self-reported sleep quality, recovery experiences the previous day at home, and momentary effect. The second survey (sent out close to the end of the workday) measured job demands and stressors as well as OCBs, while the third survey in the evening assessed job strain. Data were analyzed using Hierarchical Linear Modeling (HLM). Results indicated that job demands and stressors at work made it difficult to unwind properly at home and have a good night’s sleep, which had repercussions for next day’s morning effect, which, in turn, influenced OCBs. It can be concluded that processes of recovery are vital to an individual’s daily effective functioning and behavior at work, but recovery may become impaired after a hard day’s work. Thus, our study sheds light on the potentially persistent nature of strain experienced as a result of work and points to the importance of recovery processes to enable individuals to avoid such cross-day spillover. Our paper will discuss this implication for theory and practice as well as potential directions for future research.

Keywords: affect, job demands, organizational citizenship behavior, recovery, strain

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Authors: Edison A. Bonifaz

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In this work, a numerical procedure is proposed to design dense multi-material structures using the Directed Energy Deposition (DED) process. A thermo-mechanical finite element model to predict thermal cycles and residual stresses is presented. A numerical layer build-up procedure coupled with a moving heat flux was constructed to minimize strains and residual stresses that result in the multi-layer deposition of an AISI 316 austenitic steel on an AISI 304 austenitic steel substrate. To simulate the DED process, the automated interface of the ABAQUS AM module was used to define element activation and heat input event data as a function of time and position. Of this manner, the construction of ABAQUS user-defined subroutines was not necessary. Thermal cycles and thermally induced stresses created during the multi-layer deposition metal AM pool crystallization were predicted and validated. Results were analyzed in three independent metal layers of three different experiments. The one-way heat and material deposition toolpath used in the analysis was created with a MatLab path script. An optimal combination of feedstock and heat input printing parameters suitable for fabricating multi-material dense structures in the directed energy deposition metal AM process was established. At constant power, it can be concluded that the lower the heat input, the lower the peak temperatures and residual stresses. It means that from a design point of view, the one-way heat and material deposition processing toolpath with the higher welding speed should be selected.

Keywords: event series, thermal cycles, residual stresses, multi-pass welding, abaqus am modeler

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Authors: Zainab Mutlaq Ibrahim, Mohamed Bader-El-Den, Mihaela Cocea

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Students' textual feedback can hold unique patterns and useful information about learning process, it can hold information about advantages and disadvantages of teaching methods, assessment components, facilities, and other aspects of teaching. The results of analysing such a feedback can form a key point for institutions’ decision makers to advance and update their systems accordingly. This paper proposes a data mining framework for analysing end of unit general textual feedback using part of speech feature (PoS) with four machine learning algorithms: support vector machines, decision tree, random forest, and naive bays. The proposed framework has two tasks: first, to use the above algorithms to build an optimal model that automatically classifies the whole data set into two subsets, one subset is tailored to assessment practices (assessment related), and the other one is the non-assessment related data. Second task to use the same algorithms to build an optimal model for whole data set, and the new data subsets to automatically detect their sentiment. The significance of this paper is to compare the performance of the above four algorithms using part of speech feature to the performance of the same algorithms using n-grams feature. The paper follows Knowledge Discovery and Data Mining (KDDM) framework to construct the classification and sentiment analysis models, which is understanding the assessment domain, cleaning and pre-processing the data set, selecting and running the data mining algorithm, interpreting mined patterns, and consolidating the discovered knowledge. The results of this paper experiments show that both models which used both features performed very well regarding first task. But regarding the second task, models that used part of speech feature has underperformed in comparison with models that used unigrams and bigrams.

Keywords: assessment, part of speech, sentiment analysis, student feedback

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Authors: A. Elragig, S. Townley, H. Dreiwi

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In this paper we introduce a bacteria-leukocyte model with bacteria chemotaxsis. We assume that bacteria develop a tactic defense mechanism as a response to Leukocyte phagocytosis. We explore the effect of this tactic motion on Turing space in two parameter spaces. A fine tuning of bacterial chemotaxis shows a significant effect on developing a non-uniform steady state.

Keywords: chemotaxis-diffusion driven instability, bacterial chemotaxis, mathematical biology, ecology

Procedia PDF Downloads 359

Authors: Huda Al-Shuaily, E. M. Lacap

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Higher Education is one of the most essential fundamentals for the advancement and progress of a country. It demands to be as accessible as possible and as comprehensive as it can be reached. In this paper, we succeeded to expand the accessibility and delivery of higher education using an Open Educational Resources (OER), a freely accessible, openly licensed documents, and media for teaching and learning. This study creates a comparative design of student’s academic performance on the course Introduction to Database and student engagement to the virtual learning environment (VLE). The study was done in two successive semesters - one without using the OER and the other is using OER. In the study, we established that there is a significant increase in student’s engagement in VLE in the latter semester compared to the former. By using the latter semester’s data, we manage to show that the student’s engagement has a positive impact on students’ academic performance. Moreso, after clustering their academic performance, the impact is seen higher for students who are low performing. The results show that these engagements can be used to potentially predict the learning styles of the student with a high degree of precision.

Keywords: EDM, learning analytics, moodle, OER, student-engagement

Procedia PDF Downloads 332

Authors: C. Mendoza Ramírez, M. Gambús Ordaz, R. Mercado Ojeda.

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Chemical solutions flooding with surfactants, based on their property of reducing the interfacial tension between crude oil and water, is a potential application of chemical enhanced oil recovery (CEOR), however, the high-rate retention of surfactants associated with adsorption in the porous medium and the complexity of the mineralogical composition of the reservoir rock generates a limitation in the efficiency of displacement of crude oil. This study evaluates the effect of the concentration of a mixture of anionic-non-ionic surfactants with silica nanoparticles, in a rock sample composed of 25.14% clay minerals of the kaolinite, chlorite, halloysite and montmorillonite type, according to the results of X-Ray Diffraction analysis and Scanning Electron Spectrometry (XRD and SEM, respectively). The amount of the surfactant mixture adsorbed on the clay rock minerals was analyzed from the construction of its calibration curve and the 4-Region Isotherm Model in a UV-Visible spectroscopy. The adsorption rate of the surfactant in the clay rock averages 32% across all concentrations, influenced by the presence of the surface area of the substrate with a value of 1.6 m2/g and by the mineralogical composition of the clay that increases the cation exchange capacity (CEC). In addition, on Region I and II a final concentration measurement is not evident in the UV-VIS, due to its ionic nature, its high affinity with the clay rock and its low concentration. Finally, for potential CEOR applications, the adsorption of these mixed surfactant systems is considered due to their industrial relevance and it is concluded that it is possible to use concentrations in Region III and IV; initially the adsorption has an increasing slope and then reaches zero in the equilibrium where interfacial tension values are reached in the order of x10-1 mN/m.

Keywords: anionic–nonionic surfactants, clay rock, adsorption, 4-region isotherm model, cation exchange capacity, critical micelle concentration, enhanced oil recovery

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Authors: Deginet Aklilu, Tianqi Wang, Endwoke Amsalu, Wei Feng, Zhiwei Li, Xia Li, Lixin Tao, Yanxia Luo, Moning Guo, Xiangtong Liu, Xiuhua Guo

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Extreme temperature-related cardiovascular diseases (CVDs) have become a growing public health concern. However, the impact of temperature on the cause of specific CVDs has not been well studied in the study area. The objective of this study was to assess the impact of temperature on cause-specific cardiovascular hospital admissions in Beijing, China. We obtained data from 172 large general hospitals from the Beijing Public Health Information Center Cardiovascular Case Database and China. Meteorological Administration covering 16 districts in Beijing from 2013 to 2017. We used a time-stratified case crossover design with a distributed lag nonlinear model (DLNM) to derive the impact of temperature on CVD in hospitals back to 27 days on CVD admissions. The temperature data were stratified as cold (extreme and moderate ) and hot (moderate and extreme ). Within five years (January 2013-December 2017), a total of 460,938 (male 54.9% and female 45.1%) CVD admission cases were reported. The exposure-response relationship for hospitalization was described by a "J" shape for the total and cause-specific. An increase in the six-day moving average temperature from moderate hot (30.2 °C) to extreme hot (36.9 °C) resulted in a significant increase in CVD admissions of 16.1%(95% CI = 12.8%-28.9%). However, the effect of cold temperature exposure on CVD admissions over a lag time of 0-27 days was found to be non significant, with a relative risk of 0.45 (95% CI = 0.378-0.55) for extreme cold (-8.5 °C)and 0.53 (95% CI = 0.47-0.60) for moderate cold (-5.6 °C). The results of this study indicate that exposure to extremely high temperatures is highly associated with an increase in cause-specific CVD admissions. These finding may guide to create and raise awareness of the general population, government and private sectors regarding on the effects of current weather conditions on CVD.

Keywords: admission, Beijing, cardiovascular diseases, distributed lag non linear model, temperature

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Authors: Laila Niklasson

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The aim of the study is to critically discuss how partner schools are engaged during Initial teacher education, ITE. The background is an experiment in Sweden where the practicum organization is reorganized due to a need to enhance quality during practicum. It is a national initiative from the government, supported by the National Agency of Education and lasts 2014-2019. The main features are concentration of students to school with a certain amount of mentors, mentors who have a mentor education and teachers with relevant subject areas and where there could be a mentor team with a leader at the school. An expected outcome is for example that the student teachers should be engaged in peer-learning. The schools should be supported by extra lectures from university teachers during practicum and also extra research projects where the schools should be engaged. A case study of one university based ITE was carried out to explore the consequences for the schools not selected. The result showed that from engaging x schools in a region, x was engaged. The schools are both in urban and rural areas, mainly in the latter. There is also a tendency that private schools are not engaged. On a unit level recruitment is perceived as harder for schools not engaged. In addition they cannot market themselves as ´selected school´ which can affect parent´s selection of school for their children. Also, on unit level, but with consequences for professional development, they are not selected for research project and thereby are not fully supported during school development. The conclusion is that from an earlier inclusive approach concerning professions where all teachers were perceived as possible mentors, there is a change to an exclusive approach where selected schools and selected teachers should be engaged. The change could be perceived as a change in governance mentality, but also in how professions are perceived, and development work is pursued.

Keywords: initial teacher education, practicum schools, profession, quality development

Procedia PDF Downloads 138

Authors: Ishrar Tabassum, Jay Andrew Saptok, Khalid Raihan Kabir, Elmee Tabassum

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The purpose of this study is to bring light to the current state of the working environments in the corporate environment and other such institutions with a particular focus on the Bangladesh National Building Code (BNBC) and its guidelines for accommodating the physically disabled. Data were collected via semi-formal interviews, site visits and focus groups conducted using a preset questionnaire as the guidelines. After conducting surveys at corporate offices of 20 organizations from major commercial sectors in Dhaka city, the auditing showed many inadequacies, as aside from the larger corporate offices, the offices have little to no accessibility for the physically disabled. This study hopes to shed light on the fact that the existing BNBCs lack of emphasis on ensuring the accessibility of the handicapped in corporate buildings in the hope that, in the future, the physically disabled will have greater opportunities at being productive members of the workforce.

Keywords: person with disability, PWD, corporate buildings, Dhaka City

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Authors: M. A. El-Khateeb

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The growth of the olive oil production in Saudi Arabia peculiarly in Al Jouf region in recent years has been accompanied by an increase in the discharge of associated processing waste. Olive mill waste is produced throughout the extraction of oil from the olive fruit using the traditional mill and press process. Deterioration of the environment due to olive mill disposal wastes is a serious problem. When olive mill waste disposed into the soil, it affects soil quality, soil micro flora, and also toxic to plants. The aim of this work is to isolate microorganism (bacterial or fungal strains) from OMW capable of degrading phenols. Olive mill wastewater, olive mill waste and soil (beside oil production mill) contaminated with olive waste were used for isolation of phenol tolerant microorganisms. Four strains (two fungal and two bacterial) were isolated from olive mill waste. The isolated strains were Candida tropicalis and Phanerochaete chrysosporium (fungal strains) and Bacillus sp. and Rhodococcus sp. (bacterial strains). These strains were able to degrade phenols and could be used for bioremediation of olive mill waste.

Keywords: bioremediation, bacteria, fungi, Sakaka

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Authors: Katarzyna Bialik-Wąs, Klaudia Pluta, Dagmara Malina, Małgorzata Miastkowska

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In recent years, biocompatible hydrogels have been used more and more in medical applications, especially as modern dressings and drug delivery systems. The main goal of this research was the characteristics of bio-hybrid hydrogel materials incorporated with the nanocarrier-drug system, which enable the release in a gradual and prolonged manner, up to 7 days. Therefore, the use of such a combination will provide protection against mechanical damage and adequate hydration. The proposed bio-hybrid hydrogels are characterized by: transparency, biocompatibility, good mechanical strength, and the dual release system, which allows for gradual delivery of the active substance, even up to 7 days. Bio-hybrid hydrogels based on sodium alginate (SA), poly(vinyl alcohol) (PVA), glycerine, and Aloe vera solution (AV) were obtained through the chemical crosslinking method using poly(ethylene glycol) diacrylate as a crosslinking agent. Additionally, a nanocarrier-drug system was incorporated into SA/PVA/AV hydrogel matrix. Here, studies were focused on the release profiles of active substances from bio-hybrid hydrogels using the USP4 method (DZF II Flow-Through System, Erweka GmbH, Langen, Germany). The equipment incorporated seven in-line flow-through diffusion cells. The membrane was placed over support with an orifice of 1,5 cm in diameter (diffusional area, 1.766 cm²). All the cells were placed in a cell warmer connected with the Erweka heater DH 2000i and the Erweka piston pump HKP 720. The piston pump transports the receptor fluid via seven channels to the flow-through cells and automatically adapts the setting of the flow rate. All volumes were measured by gravimetric methods by filling the chambers with Milli-Q water and assuming a density of 1 g/ml. All the determinations were made in triplicate for each cell. The release study of the model active substance was carried out using a regenerated cellulose membrane Spectra/Por®Dialysis Membrane MWCO 6-8,000 Carl Roth® Company. These tests were conducted in buffer solutions – PBS at pH 7.4. A flow rate of receptor fluid of about 4 ml /1 min was selected. The experiments were carried out for 7 days at a temperature of 37°C. The released concentration of the model drug in the receptor solution was analyzed using UV-Vis spectroscopy (Perkin Elmer Company). Additionally, the following properties of the modified materials were studied: physicochemical, structural (FT-IR analysis), morphological (SEM analysis). Finally, the cytotoxicity tests using in vitro method were conducted. The obtained results exhibited that the dual release system allows for the gradual and prolonged delivery of the active substances, even up to 7 days.

Keywords: wound dressings, SA/PVA hydrogels, nanocarrier-drug system, USP4 method

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Authors: Șercăianu Mihai, Aldea Mihaela, Iacoboaea Cristina, Luca Oana, Nenciu Ioana

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The rise and mitigation of unauthorized illegal waste dumps are a significant global issue within waste management ecosystems, impacting disadvantaged communities. Globally, including in Romania, many individuals live in houses without legal recognition, lacking ownership or construction permits, in areas known as "informal settlements." An increasing number of regions and cities in Romania are struggling to manage their illegal waste dumps, especially in the context of increasing poverty and lack of regulation related to informal settlements. One such informal settlement is located at the end of Bistra Street in Câlnic, within the Reșița Municipality of Caras Severin County. The article presents a case study that focuses on employing remote sensing techniques and spatial data to monitor and map illegal waste practices, with subsequent integration into a geographic information system tailored for the Reșița community. In addition, the paper outlines the steps involved in devising strategies aimed at enhancing waste management practices in disadvantaged areas, aligning with the shift toward a circular economy. Results presented in the paper contain a spatial mapping and visualization methodology calibrated with in situ data collection applicable for identifying illegal landfills. The emergence and neutralization of illegal dumps pose a challenge in the field of waste management. These approaches, which prove effective where conventional solutions have failed, need to be replicated and adopted more wisely.

Keywords: informal settlements, GIS, waste dumps, waste management, monitoring

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Authors: Mohamed Anouar Razgallah

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This paper examines in the context of a one-period model the impact of background risk on the optimal secondary prevention. We conduct our study based on various configurations of the background risk. We intend to show that in most cases the level of secondary prevention effort varied after the introduction of background risk, however, in very few cases this level remains constant.

Keywords: secondary prevention, primary prevention, background risk, ecomomics

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Authors: F. B. Masok, S. S Songdeg, R. R. Dawam

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Vision is an important process for learning and communication as man depends greatly on vision to sense his environment. Prevalence and variation of refractive errors conducted between December 2010 and May 2011 in Jos, revealed that 735 (77.50%) out 950 subjects examined for refractive error had various refractive errors. Myopia was observed in 373 (49.79%) of the subjects, the error in the right eyes was 263 (55.60%) while the error in the left was 210(44.39%). The mean myopic error was found to be -1.54± 3.32. Hyperopia was observed in 385 (40.53%) of the sampled population comprising 203(52.73%) of the right eyes and 182(47.27%). The mean hyperopic error was found to be +1.74± 3.13. Astigmatism accounted for 359 (38.84%) of the subjects, out of which 193(53.76%) were in the right eyes while 168(46.79%) were in the left eyes. Presbyopia was found in 404(42.53%) of the subjects, of this figure, 164(40.59%) were in the right eyes while 240(59.41%) were in left eyes. The number of right eyes and left eyes with refractive errors was observed in some age groups to increase with age and later had its peak within 60 – 69 age groups. This pattern of refractive errors could be attributed to exposure to various forms of light particularly the ultraviolet rays (e.g rays from television and computer screen). There was no remarkable differences between the mean Myopic error and mean Hyperopic error in the right eyes and in the left eyes which suggest the right eye and the left eye are similar.

Keywords: left eye, refractive errors, right eye, variation

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Authors: Dilip Gogoi

Abstract:

This paper attempts to explore the notion of sovereign state system, its emergence and legitimization by the treaty of Westphalia, 1648 in Europe and examines how the very notion of sovereign state is subject to changes in the later part of the 20th century both politically and economically in the wake of globalisation. The paper firstly traces the tradition of Westphalian sovereign state system which influenced the dominant understanding about sovereign state system till mid 20th century. Secondly, it explores how the notion of sovereign nation state is subjected to change in the post World War II specially in the context of universal acceptance of human rights and right to intervene in internal affairs of a sovereign state to protect the same, the decolonization and legitimization of the principle of self determination and through the experience of European Integration. Thirdly, it analyses how globalisation drives certain fundamental changes and poses challenges to the sovereign state system. The concluding part of the paper argues that sovereign state system is relevant and will continue to be relevant although it needs to redefine its role in the changing global environment.

Keywords: Westphalia, sovereignty, nation-state system, intervention, globalisation

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Authors: Akbar Esmaeili, Azadeh Asgari

Abstract:

Essential oils’ unique and practical properties have been widely reported in recent years. Still, the sensitivity of critical oils to environmental factors and their poor solubility in aqueous solutions have limited their use in industries. Therefore, we encapsulated C. copticum essential oil in chitosan nanoparticles by emulsion-ionic gelation with sodium tripolyphosphate and sodium hexametaphosphate cross-linkers. The nanoparticles showed a round shape with an average size of 30-80 nm and a regular distribution. The release profile in the laboratory environment showed a burst in the initial release and then a stable release of C. copticum essential oil from chitosan nanoparticles at different pH. Antioxidant and antibacterial properties of C. copticum essential oil before and after the encapsulation process were evaluated by 2,2-diphenyl-1-picrylhydrazyl radical and disc diffusion methods, respectively. The results showed that the encapsulation of C. copticum essential oil in chitosan nanoparticles could protect its quality and bioactive compounds and improve the properties of the crucial oil.

Keywords: essential oils, Carum copticum, biological activities, nanotechnology

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Authors: Yadi Xu, Qingping Luo

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Currently, there is a great tendency that more and more villages in China are trying to increase income by development of tourism. 'Beautiful Rural Construction' provides an excellent opportunity for the development of tourism. In this context, development orientation, transportation routes, and tourism service facilities are analyzed under the perspective of existing landscape utilization and regional integration based on the development tourism industry of the Nanliangdu Village in Jingxing Town, Shijiazhuang Province as a research object. In the program, the biggest issue is the contradiction between the ecological development and protection of the river and the development of economy. How to deal with the relationship between protection and development is the key to the design of this case. Furthermore, the streets and courtyard space, existing buildings, public environment, specific landscape of the ancient village with a history of thousands of years have strong regional characteristics. The article is actively exploring for suggestions and countermeasures to promote the development premised on protection and based on a regional view.

Keywords: development, integration, protection, rural tourism

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Authors: Wisdom Dordudnu, George M. Y. Owusu, Samuel N. Y. Simpson

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The recent failures of many corporate giants have generated intense research interest in the factors that influence accountants’ job performance. Against the backdrop that these factors also create an enabling environment for success at the work place, this study contributes to literature on job performance of accountants by exploring the impact of two psycho-spiritual factors: religiosity and spiritual intelligence on job performance of accountants in Ghana. The study employs a survey approach using questionnaires as the principal means of data collection to elicit responses from accountants working in the 222 certified firms of Institute of Chartered Accountants Ghana (ICAG). A structural equation modeling-based approach is employed to examine the relationship among the study constructs. Results of this study indicate that there is a positive relationship between these factors and accountants’ performance. It is expected that this study provides strong evidence and highlight the need for specific action from managers to look critically at the non-material aspect of accountants in accounting firms.

Keywords: job performance, psycho-spiritual, religiosity, spiritual intelligence

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Authors: Hoong C. Chin, Soon H. Chew, Zhaoxia Wang

Abstract:

Work on sustainable developments and the call for action in education for sustainable development have been ongoing for a number of years. Training engineering students with the relevant competencies, particularly in sustainable development literacy, has been identified as an urgent task in universities. This requires not only a holistic, multi-disciplinary approach to education but also a suitable training environment to develop the needed skills and to inculcate the appropriate attitudes in students towards sustainable development. To demonstrate how this can be done, a module involving an overseas field trip was introduced in 2013 at the National University of Singapore. This paper provides details of the module and describes its training philosophy and methods. Measured against the student learning outcomes, stipulated by the Engineering Accreditation Board, the module scored well on all of them, particularly those related to complex problem solving, environmental and sustainability awareness, multi-disciplinary team work and varied-level communications.

Keywords: civil engineering education, socio-economically sustainable infrastructure, student learning outcome, sustainable development

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Authors: Maha Bakkari, R.Tadili

Abstract:

The present work is a study of the performance of a solar copper coil heating system in a greenhouse microclimate. Our system is based on the circulation of a Heat transfer fluid, which is water in our case, in a closed loop under the greenhouse's roof in order to store heat all day, and then this heat will supply the greenhouse during the night. In order to evaluate our greenhouse, we made an experimental study in two identical greenhouses, where the first one is equipped with a heating system and the second (without heating) is used for control. The heating system allows the establishment of the thermal balance and determines the mass of water necessary for the process in order to ensure its functioning during the night. The results obtained showed that this solar heating system and the climatic parameters inside the experimental greenhouse were improved, and it presents a significant gain compared to a controlled greenhouse without a heating system. This research is one of the solutions that help to reduce the greenhouse effect of the planet Earth, a problem that worries the world.

Keywords: solar energy, energy storage, greenhouse, environment

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Authors: Hira Jabbar

Abstract:

Education is vital for inclusive growth of an economy and a critical contributor for investment in human capital. Like other developing countries, Pakistan is facing enormous challenges regarding the provision of public facilities, improper infrastructure planning, accelerating rate of population and poor accessibility. The influence of the rapid advancement and innovations in GIS and RS techniques have proved to be a useful tool for better planning and decision making to encounter these challenges. Therefore present study incorporates GIS and RS techniques to investigate the spatial distribution of school facilities, identifies settlements with served and unserved population, finds potential areas for new schools based on population and develops an accessibility index to evaluate the higher accessibility for schools. For this purpose high-resolution worldview imagery was used to develop road network, settlements and school facilities and to generate school accessibility for each level. Landsat 8 imagery was utilized to extract built-up area by applying pre and post-processing models and Landscan 2015 was used to analyze population statistics. Service area analysis was performed using network analyst extension in ArcGIS 10.3v and results were evaluated for served and underserved areas and population. An accessibility tool was used to evaluate a set of potential destinations to determine which is the most accessible with the given population distribution. Findings of the study may contribute to facilitating the town planners and education authorities for understanding the existing patterns of school facilities. It is concluded that GIS and remote sensing can be effectively used in urban transport and facility planning.

Keywords: accessibility, geographic information system, landscan, worldview

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Authors: S. Amirhossein Tabatabaei, Abdulghader A. Aldaeef, Mohammad T. Rayhani

Abstract:

As the permafrost continues to melt in the northern regions due to global warming, a soil-water mixture is left behind with drastically lower strength; a phenomenon that directly impacts the resilience of existing structures and infrastructure systems. The frozen soil-structure interaction, which in ice-poor soils is controlled by both interface shear and ice-bonding, changes its nature into a sole frictional state. Adfreeze, the controlling mechanism in frozen soil-structure interaction, diminishes as the ground temperature approaches zero. The main purpose of this paper is to capture the altered behaviour of frozen interface with respect to rising temperature, especially near melting states. A series of pull-out tests are conducted on model piles inside a cold room to study how the strength parameters are influenced by the phase change in ice-poor soils. Steel model piles, embedded in artificially frozen cohesionless soil, are subjected to both sustained pull-out forces and constant rates of displacement to observe the creep behaviour and acquire load-deformation curves, respectively. Temperature, as the main variable of interest, is increased from a lower limit of -10°C up to the point of melting. During different stages of the temperature rise, both skin deformations and temperatures are recorded at various depths along the pile shaft. Significant reduction of pullout capacity and accelerated creep behaviour is found to be the primary consequences of rising temperature. By investigating the different pull-out capacities and deformations measured during step-wise temperature change, characteristics of the transition from frozen to unfrozen soil-structure interaction are studied.

Keywords: Adfreeze, frozen soil-structure interface, ice-poor soils, pull-out capacity, warming permafrost

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