Search results for: Yobe state University
Commenced in January 2007
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Edition: International
Paper Count: 11197

Search results for: Yobe state University

1717 Ibadan-Nigeria Citizenship Behavior Scale: Development and Validation

Authors: Benjamin O. Ehigie, Aderemi Alarape, Nyitor Shenge, Sylvester A. Okhakhume, Timileyin Fashola, Fiyinfunjah Dosumu

Abstract:

Organisational citizenship behaviour (OCB) is a construct in industrial and organisational behaviour that explains a person's voluntary commitment within an organisation, which is outside the scope of his or her contractual tasks. To attain organisational effectiveness the human factor of production is inevitable, hence the importance of employee behaviour. While the concept of organisational citizenship behavior is mostly discussed in the context of the workplace, it is reasoned that the idea could be reflective in relation to national commitment. Many developing countries in Africa, including Nigeria, suffer economic hardship today not necessarily due to poor resources but bad management of the resources. The mangers of their economies are not committed to the tenets of economic growth but engrossed in fraud, corruption, bribery, and other economic vices. It is this backdrop that necessitated the development and validation of the Ibadan-Nigeria Citizenship Behaviour (I-NCB) Scale. The study adopted a cross-sectional survey (online) research design, using 2404 postgraduate students in the Premier University of the country, with 99.2% being Nigerians and 0.8% non-Nigerians. Gender composition was 1,439 (60%) males and 965 (40%) females, 1201 (50%) were employed while 1203 50% unemployed, 74.2% of the employed were in public paid employment, 19.5% in private sector, and 6.3% were self-employed. Through literature review, 78 items were generated. Using 10 lecturers and 21 students, content and face validity were established respectively. Data collected were subjected to reliability and factor analytic statistics at p < .05 level of significance. Results of the content and face validity at 80% level of item acceptance resulted to 60 items; this was further reduced to 50 after item-total correlation using r=.30 criterion. Divergent validity of r= -.28 and convergent validity of r= .44 were obtained by correlating the I-NCB scale with standardized Counterproductive work behaviour (CWB) scale and Organisational Citizenship Behaviour (OCB) scale among the workers. The reliability coefficients obtained were; Cronbach alpha of internal consistency (α = 0.941) and split-half reliability of r = 0.728. Factor analyses of the I-NCB scale with principal component and varimax rotation yielded five factors when Eigenvalue above 1 were extracted. The factors which accounted for larger proportions of the total variance were given factor names as; Altruistic, Attachment, Affective, Civic responsibility and Allegiance. As much as there are vast journals on citizenship behaviour in organisations, there exists no standardized tool to measure citizenship behaviour of a country. The Ibadan-Nigeria Citizenship Behaviour (I-NCB) scale was consequently developed. The scale could be used to select personnel into political positions and senior administrative positions among career workers in Nigeria, with the aim of determining national commitment to service.

Keywords: counterproductive work behaviour, CWB, Nigeria Citizenship Behaviour, organisational citizenship behaviour, OCB, Ibadan

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1716 Real-Time Hybrid Simulation for a Tuned Liquid Column Damper Implementation

Authors: Carlos Riascos, Peter Thomson

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Real-time hybrid simulation (RTHS) is a modern cyber-physical technique used for the experimental evaluation of complex systems, that treats the system components with predictable behavior as a numerical substructure and the components that are difficult to model as an experimental substructure. Therefore it is an attractive method for evaluation of the response of civil structures under earthquake, wind and anthropic loads. Another practical application of RTHS is the evaluation of control systems, as these devices are often nonlinear and their characterization is an important step in the design of controllers with the desired performance. In this paper, the response of three-story shear frame controlled by a tuned liquid column damper (TLCD) and subject to base excitation is considered. Both passive and semi-active control strategies were implemented and are compared. While the passive TLCD achieved a reduction of 50% in the acceleration response of the main structure in comparison with the structure without control, the semi-active TLCD achieved a reduction of 70%, and was robust to variations in the dynamic properties of the main structure. In addition, a RTHS was implemented with the main structure modeled as a linear, time-invariant (LTI) system through a state space representation and the TLCD, with both control strategies, was evaluated on a shake table that reproduced the displacement of the virtual structure. Current assessment measures for RTHS were used to quantify the performance with parameters such as generalized amplitude, equivalent time delay between the target and measured displacement of the shake table, and energy error using the measured force, and prove that the RTHS described in this paper is an accurate method for the experimental evaluation of structural control systems.

Keywords: structural control, hybrid simulation, tuned liquid column damper, semi-active sontrol strategy

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1715 Transverse Momentum Dependent Factorization and Evolution for Spin Physics

Authors: Bipin Popat Sonawane

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After 1988 Electron muon Collaboration (EMC) announcement of measurement of spin dependent structure function, it has been found that it has become a need to understand spin structure of a hadron. In the study of three-dimensional spin structure of a proton, we need to understand the foundation of quantum field theory in terms of electro-weak and strong theories using rigorous mathematical theories and models. In the process of understanding the inner dynamical stricture of proton we need understand the mathematical formalism in perturbative quantum chromodynamics (pQCD). In QCD processes like proton-proton collision at high energy we calculate cross section using conventional collinear factorization schemes. In this calculations, parton distribution functions (PDFs) and fragmentation function are used which provide the information about probability density of finding quarks and gluons ( partons) inside the proton and probability density of finding final hadronic state from initial partons. In transverse momentum dependent (TMD) PDFs and FFs, collectively called as TMDs, take an account for intrinsic transverse motion of partons. The TMD factorization in the calculation of cross sections provide a scheme of hadronic and partonic states in the given QCD process. In this study we review Transverse Momentum Dependent (TMD) factorization scheme using Collins-Soper-Sterman (CSS) Formalism. CSS formalism considers the transverse momentum dependence of the partons, in this formalism the cross section is written as a Fourier transform over a transverse position variable which has physical interpretation as impact parameter. Along with this we compare this formalism with improved CSS formalism. In this work we study the TMD evolution schemes and their comparison with other schemes. This would provide description in the process of measurement of transverse single spin asymmetry (TSSA) in hadro-production and electro-production of J/psi meson at RHIC, LHC, ILC energy scales. This would surely help us to understand J/psi production mechanism which is an appropriate test of QCD.

Keywords: QCD, PDF, TMD, CSS

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1714 Arabic Lexicon Learning to Analyze Sentiment in Microblogs

Authors: Mahmoud B. Rokaya

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The study of opinion mining and sentiment analysis includes analysis of opinions, sentiments, evaluations, attitudes, and emotions. The rapid growth of social media, social networks, reviews, forum discussions, microblogs, and Twitter, leads to a parallel growth in the field of sentiment analysis. The field of sentiment analysis tries to develop effective tools to make it possible to capture the trends of people. There are two approaches in the field, lexicon-based and corpus-based methods. A lexicon-based method uses a sentiment lexicon which includes sentiment words and phrases with assigned numeric scores. These scores reveal if sentiment phrases are positive or negative, their intensity, and/or their emotional orientations. Creation of manual lexicons is hard. This brings the need for adaptive automated methods for generating a lexicon. The proposed method generates dynamic lexicons based on the corpus and then classifies text using these lexicons. In the proposed method, different approaches are combined to generate lexicons from text. The proposed method classifies the tweets into 5 classes instead of +ve or –ve classes. The sentiment classification problem is written as an optimization problem, finding optimum sentiment lexicons are the goal of the optimization process. The solution was produced based on mathematical programming approaches to find the best lexicon to classify texts. A genetic algorithm was written to find the optimal lexicon. Then, extraction of a meta-level feature was done based on the optimal lexicon. The experiments were conducted on several datasets. Results, in terms of accuracy, recall and F measure, outperformed the state-of-the-art methods proposed in the literature in some of the datasets. A better understanding of the Arabic language and culture of Arab Twitter users and sentiment orientation of words in different contexts can be achieved based on the sentiment lexicons proposed by the algorithm.

Keywords: social media, Twitter sentiment, sentiment analysis, lexicon, genetic algorithm, evolutionary computation

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1713 Prospective Analysis of Micromobility in the City of Medellín

Authors: Saúl Rivero, Estefanya Marín, Katherine Bolaño, Elena Urán, Juan Yepes, Andrés Cossio

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Medellín is the Colombian city with the best public transport systems in the country, which is made up of two metro lines, five metrocables, two BRT-type bus lines, and a tram. But despite the above, the Aburrá Valley, the area in which the city is located, has about 3000 km of roads, which for the existing population of 3.2 million inhabitants, gives an indicator of 900 meters of road per 1000 inhabitants, which is lower than the country's average, which is approximately 3900 meters. In addition, given that in Medellín, there is approximately one vehicle for every three inhabitants, the problems of congestion and environmental pollution have worsened over the years. In this sense, due to the limitations of physical space, the low public investment in road infrastructure, it is necessary to opt for mobility alternatives according to the above. Among the options for the city, there is what is known as micromobility. Micromobility is understood to be those small and light means of transport that are used for short distances, that use electrical energy, such as skateboards and bicycles. Taking into account the above, in this work, the current state and future of micromobility in the city of Medellín were analyzed, carrying out a prospective analysis, supported by a PEST analysis, but also of the crossed impact matrices; of influence and dependence; and the technique of the actor's game. The analysis was carried out for two future scenarios: one normal and one optimistic. Result of the analysis, it was determined that micromobility as an alternative social practice to mobility in the city of Medellín has favorable conditions since the local government has adopted strategies such as the Metropolitan Bicycle Master Plan of Valle de Aburrá and the plan " Bicycle paths in the city: more public spaces for life,” where a projection of 400 kilometers of bicycle paths was estimated by the year 2030, as for that same year it is expected that 10% of all trips in the region will be in bike mode. The total trip indicator is an achievable goal, while that of the number of kilometers of bike paths would be close to being met.

Keywords: electric vehicles, micromobilty, public transport, sustainable transport

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1712 Thermal Imaging of Aircraft Piston Engine in Laboratory Conditions

Authors: Lukasz Grabowski, Marcin Szlachetka, Tytus Tulwin

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The main task of the engine cooling system is to maintain its average operating temperatures within strictly defined limits. Too high or too low average temperatures result in accelerated wear or even damage to the engine or its individual components. In order to avoid local overheating or significant temperature gradients, leading to high stresses in the component, the aim is to ensure an even flow of air. In the case of analyses related to heat exchange, one of the main problems is the comparison of temperature fields because standard measuring instruments such as thermocouples or thermistors only provide information about the course of temperature at a given point. Thermal imaging tests can be helpful in this case. With appropriate camera settings and taking into account environmental conditions, we are able to obtain accurate temperature fields in the form of thermograms. Emission of heat from the engine to the engine compartment is an important issue when designing a cooling system. Also, in the case of liquid cooling, the main sources of heat in the form of emissions from the engine block, cylinders, etc. should be identified. It is important to redesign the engine compartment ventilation system. Ensuring proper cooling of aircraft reciprocating engine is difficult not only because of variable operating range but mainly because of different cooling conditions related to the change of speed or altitude of flight. Engine temperature also has a direct and significant impact on the properties of engine oil, which under the influence of this parameter changes, in particular, its viscosity. Too low or too high, its value can be a result of fast wear of engine parts. One of the ways to determine the temperatures occurring on individual parts of the engine is the use of thermal imaging measurements. The article presents the results of preliminary thermal imaging tests of aircraft piston diesel engine with a maximum power of about 100 HP. In order to perform the heat emission tests of the tested engine, the ThermaCAM S65 thermovision monitoring system from FLIR (Forward-Looking Infrared) together with the ThermaCAM Researcher Professional software was used. The measurements were carried out after the engine warm up. The engine speed was 5300 rpm The measurements were taken for the following environmental parameters: air temperature: 17 °C, ambient pressure: 1004 hPa, relative humidity: 38%. The temperatures distribution on the engine cylinder and on the exhaust manifold were analysed. Thermal imaging tests made it possible to relate the results of simulation tests to the real object by measuring the rib temperature of the cylinders. The results obtained are necessary to develop a CFD (Computational Fluid Dynamics) model of heat emission from the engine bay. The project/research was financed in the framework of the project Lublin University of Technology-Regional Excellence Initiative, funded by the Polish Ministry of Science and Higher Education (contract no. 030/RID/2018/19).

Keywords: aircraft, piston engine, heat, emission

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1711 Experimental Study of an Isobaric Expansion Heat Engine with Hydraulic Power Output for Conversion of Low-Grade-Heat to Electricity

Authors: Maxim Glushenkov, Alexander Kronberg

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Isobaric expansion (IE) process is an alternative to conventional gas/vapor expansion accompanied by a pressure decrease typical of all state-of-the-art heat engines. The elimination of the expansion stage accompanied by useful work means that the most critical and expensive parts of ORC systems (turbine, screw expander, etc.) are also eliminated. In many cases, IE heat engines can be more efficient than conventional expansion machines. In addition, IE machines have a very simple, reliable, and inexpensive design. They can also perform all the known operations of existing heat engines and provide usable energy in a very convenient hydraulic or pneumatic form. This paper reports measurement made with the engine operating as a heat-to-shaft-power or electricity converter and a comparison of the experimental results to a thermodynamic model. Experiments were carried out at heat source temperature in the range 30–85 °C and heat sink temperature around 20 °C; refrigerant R134a was used as the engine working fluid. The pressure difference generated by the engine varied from 2.5 bar at the heat source temperature 40 °C to 23 bar at the heat source temperature 85 °C. Using a differential piston, the generated pressure was quadrupled to pump hydraulic oil through a hydraulic motor that generates shaft power and is connected to an alternator. At the frequency of about 0.5 Hz, the engine operates with useful powers up to 1 kW and an oil pumping flowrate of 7 L/min. Depending on the temperature of the heat source, the obtained efficiency was 3.5 – 6 %. This efficiency looks very high, considering such a low temperature difference (10 – 65 °C) and low power (< 1 kW). The engine’s observed performance is in good agreement with the predictions of the model. The results are very promising, showing that the engine is a simple and low-cost alternative to ORC plants and other known energy conversion systems, especially at low temperatures (< 100 °C) and low power range (< 500 kW) where other known technologies are not economic. Thus low-grade solar, geothermal energy, biomass combustion, and waste heat with a temperature above 30 °C can be involved into various energy conversion processes.

Keywords: isobaric expansion, low-grade heat, heat engine, renewable energy, waste heat recovery

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1710 Reaching Students Who “Don’t Like Writing” through Scenario Based Learning

Authors: Shahira Mahmoud Yacout

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Writing is an essential skill in many vocational, academic environments, and notably workplaces, yet many students perceive writing as being something tiring and boring or maybe a “waste of time”. Studies in the field of foreign languages related this fact might be due to the lack of connection between what is learned in the university and what students come to encounter in real life situations”. Arabic learners felt they needed more language exposure to the context of their future professions. With this idea in mind, Scenario based learning (SBL) is reported to be an educational approach to motivate, engage and stimulate students’ interest and to achieve the desired writing learning outcomes. In addition, researchers suggested Scenario based learning (SBL)as an instructional approach that develops and enhances students skills through developing higher order thinking skills and active learning. It is a subset of problem-based learning and case-based learning. The approach focuses on authentic rhetorical framing reflecting writing tasks in real life situations. It works successfully when used to simulate real-world practices, providing context that reflects the types of situations professionals respond to in writing. It was claimed that using realistic scenarios customized to the course’s learning objectives as it bridged the gap for students between theory and application. Within this context, it is thought that scenario-based learning is an important approach to enhance the learners’ writing skills and to reflect meaningful learning within authentic contexts. As an Arabicforeign language instructor, it was noticed that students find difficulties in adapting writing styles to authentic writing contexts and addressing different audiences and purposes. This idea is supported by studieswho claimed that AFL students faced difficulties with transferring writing skills to situations outside of the classroom context. In addition, it was observed that some of the Arabic textbooks for teaching Arabic as a foreign language lacked topics that initiated higher order thinking skills and stimulated the learners to understand the setting, and created messages appropriate to different audiences, context, and purposes. The goals of this study are to 1)provide a rational for using scenario-based learning approach to improveAFL learners in writing skills, 2) demonstrate how to design/ implement a scenario-based learning technique aligned with the writing course objectives,3) demonstrate samples of scenario-based approach implemented in AFL writing class, and 4)emphasis the role of peer-review along with the instructor’s feedback, in the process of developing the writing skill. Finally, this presentation highlighted and emphasized the importance of using the scenario-based learning approach in writing as a means to mirror students’ real-life situations and engage them in planning, monitoring, and problem solving. This approach helped in making writing an enjoyable experience and clearly useful to students’ future professional careers.

Keywords: meaningful learning, real life contexts, scenario based learning, writing skill

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1709 Preventing Discharge to No Fixed Address-Youth (NFA-Y)

Authors: Cheryl Forchuk, Sandra Fisman, Steve Cordes, Dan Catunto, Katherine Krakowski, Melissa Jeffrey, John D’Oria

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The discharge of youth aged 16-25 from hospital into homelessness is a prevalent issue despite research indicating social, safety, health and economic detriments on both the individual and community. Lack of stable housing for youth discharged into homelessness results in long-term consequences, including exacerbation of health problems and costly health care service use and hospital readmission. People experiencing homelessness are four times more likely to be readmitted within one month of discharge and hospitals must spend $2,559 more per client. Finding safe housing for these individuals is imperative to their recovery and transition back to the community. People discharged from hospital to homelessness experience challenges, including poor health outcomes and increased hospital readmissions. Youth are the fastest-growing subgroup of people experiencing homelessness in Canada. The needs of youth are unique and include supports related to education, employment opportunities, and age-related service barriers. This study aims to identify the needs of youth at risk of homelessness by evaluating the efficacy of the “Preventing Discharge to No Fixed Address – Youth” (NFA-Y) program, which aims to prevent youth from being discharged from hospital into homelessness. The program connects youth aged 16-25 who are inpatients at London Health Sciences Centre and St. Joseph’s Health Care London to housing and financial support. Supports are offered through collaboration with community partners: Youth Opportunities Unlimited, Canadian Mental Health Association Elgin Middlesex, City of London Coordinated Access, Ontario Works, and Salvation Army’s Housing Stability Bank. This study was reviewed and approved by Western University’s Research Ethics Board. A series of interviews are being conducted with approximately ninety-three youth participants at three time points: baseline (pre-discharge), six, and twelve months post-discharge. Focus groups with participants, health care providers, and community partners are being conducted at three-time points. In addition, administrative data from service providers will be collected and analyzed. Since homelessness has a detrimental effect on recovery, client and community safety, and healthcare expenditure, locating safe housing for psychiatric patients has had a positive impact on treatment, rehabilitation, and the system as a whole. If successful, the findings of this project will offer safe policy alternatives for the prevention of homelessness for at-risk youth, help set them up for success in their future years, and mitigate the rise of the homeless youth population in Canada.

Keywords: youth homelessness, no-fixed address, mental health, homelessness prevention, hospital discharge

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1708 Investigation of Correlation Between Radon Concentration and Metals in Produced Water from Oilfield Activities

Authors: Nacer Hamza

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Naturally radiation exposure that present due to the cosmic ray or the naturel occurring radioactives materials(NORMs) that originated in the earth's crust and are present everywhere in the environment(1) , a significant concentration of NORMs reported in the produced water which comes out during the oil extraction process, so that the management of this produced water is a challenge for oil and gas companies which include either minimization of produced water which considered as the best way in the term of environment based in the fact that ,the lower water produced the lower cost in treating this water , recycling and reuse by reinjected produced water that fulfills some requirements to enhance oil recovery or disposal in the case that the produced water cannot be minimize or reuse. In the purpose of produced water management, the investigation of NORMs activity concentration present in it considered as the main step for more understanding of the radionuclide’s distribution. Many studies reported the present of NORMs in produced water and investigated the correlation between 〖Ra〗^226and the different metals present in produced water(2) including Cations and anions〖Na〗^+,〖Cl〗^-, 〖Fe〗^(2+), 〖Ca〗^(2+) . and lead, nickel, zinc, cadmium, and copper commonly exist as heavy metal in oil and gas field produced water(3). However, there are no real interesting to investigate the correlation between 〖Rn〗^222and the different metals exist in produced water. methods using, in first to measure the radon concentration activity in produced water samples is a RAD7 .RAD7 is a radiometer instrument based on the solid state detectors(4) which is a type of semi-conductor detector for alpha particles emitting from Rn and their progenies, in second the concentration of different metals presents in produced water measure using an atomic absorption spectrometry AAS. Then to investigate the correlation between the 〖Rn〗^222concentration activity and the metals concentration in produced water a statistical method is Pearson correlation analysis which based in the correlation coefficient obtained between the 〖Rn〗^222 and metals. Such investigation is important to more understanding how the radionuclides act in produced water based on this correlation with metals , in first due to the fact that 〖Rn〗^222decays through the sequence 〖Po〗^218, 〖Pb〗^214, 〖Bi〗^214, 〖Po〗^214, and〖Pb〗^210, those daughters are metals thus they will precipitate with metals present in produced water, secondly the short half-life of 〖Rn〗^222 (3.82 days) lead to faster precipitation of its progenies with metals in produced water.

Keywords: norms, radon concentration, produced water, heavy metals

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1707 Reviewing Special Education Preservice Teachers' Reflective Practices over Two Field Experiences: Topics and Changes in Reflection

Authors: Laurie U. deBettencourt

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During pre-service field experiences teacher candidates are often asked to reflect as part of their training and in this investigation candidates’ reflective journal entries were reviewed, coded and analyzed with results suggesting teacher candidates need more direct instruction on how to describe, analyze, and make judgements on their instructional practices so that their practices improve over time. Teacher education programs often incorporate reflective-based activities during field experiences. The purpose of this investigation was to determine if special education teacher candidate’s reflective practices changed as they completed their two supervised field experiences and to determine what topics the candidates focused on in their reflections. The six females graduate students were completing two field experiences in special education classrooms within one academic year as part of their coursework leading to a master’s degree and special education teacher state certification. Each candidate wrote 15 reflection journal entries (approximately 200 words each) per field experience. Each of the journal entries were reviewed sentence by sentence to determine a reflective practice score and to determine the topics discussed. The reflective practice score was calculated using four dimensions of reflection (describe, analyze, judge, and apply) in order to create a continuous variable representing their reflective practice across four points of time. A One-way Repeated Measures Analysis of Variance (ANOVA) suggested that special education teacher candidates did not change their reflective practices over time (i.e., at time-point one the practitioner’s mean score was 56.0 out of 100 (SD = 7.6), 53.8 (SD = 4.3) at time-point two, 51.2 (SD = 4.5) at time-point three, and 57.7 (SD = 8.2) at time-point four). Qualitative findings suggest candidates focused mostly on themselves in their reflections. Conclusions suggest the need for teacher preparation programs to provide more direct instruction on how a teacher should reflect. Specific implications are provided for teacher training and future research.

Keywords: field experiences, reflective practices, special educators, teacher preparation

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1706 Growth and Differentiation of Mesenchymal Stem Cells on Titanium Alloy Ti6Al4V and Novel Beta Titanium Alloy Ti36Nb6Ta

Authors: Eva Filová, Jana Daňková, Věra Sovková, Matej Daniel

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Titanium alloys are biocompatible metals that are widely used in clinical practice as load bearing implants. The chemical modification may influence cell adhesion, proliferation, and differentiation as well as stiffness of the material. The aim of the study was to evaluate the adhesion, growth and differentiation of pig mesenchymal stem cells on the novel beta titanium alloy Ti36Nb6Ta compared to standard medical titanium alloy Ti6Al4V. Discs of Ti36Nb6Ta and Ti6Al4V alloy were sterilized by ethanol, put in 48-well plates, and seeded by pig mesenchymal stem cells at the density of 60×103/cm2 and cultured in Minimum essential medium (Sigma) supplemented with 10% fetal bovine serum and penicillin/streptomycin. Cell viability was evaluated using MTS assay (CellTiter 96® AQueous One Solution Cell Proliferation Assay;Promega), cell proliferation using Quant-iT™ ds DNA Assay Kit (Life Technologies). Cells were stained immunohistochemically using monoclonal antibody beta-actin, and secondary antibody conjugated with AlexaFluor®488 and subsequently the spread area of cells was measured. Cell differentiation was evaluated by alkaline phosphatase assay using p-nitrophenyl phosphate (pNPP) as a substrate; the reaction was stopped by NaOH, and the absorbance was measured at 405 nm. Osteocalcin, specific bone marker was stained immunohistochemically and subsequently visualized using confocal microscopy; the fluorescence intensity was analyzed and quantified. Moreover, gene expression of osteogenic markers osteocalcin and type I collagen was evaluated by real-time reverse transcription-PCR (qRT-PCR). For statistical evaluation, One-way ANOVA followed by Student-Newman-Keuls Method was used. For qRT-PCR, the nonparametric Kruskal-Wallis Test and Dunn's Multiple Comparison Test were used. The absorbance in MTS assay was significantly higher on titanium alloy Ti6Al4V compared to beta titanium alloy Ti36Nb6Ta on days 7 and 14. Mesenchymal stem cells were well spread on both alloys, but no difference in spread area was found. No differences in alkaline phosphatase assay, fluorescence intensity of osteocalcin as well as the expression of type I collagen, and osteocalcin genes were observed. Higher expression of type I collagen compared to osteocalcin was observed for cells on both alloys. Both beta titanium alloy Ti36Nb6Ta and titanium alloy Ti6Al4V Ti36Nb6Ta supported mesenchymal stem cellsˈ adhesion, proliferation and osteogenic differentiation. Novel beta titanium alloys Ti36Nb6Ta is a promising material for bone implantation. The project was supported by the Czech Science Foundation: grant No. 16-14758S, the Grant Agency of the Charles University, grant No. 1246314 and by the Ministry of Education, Youth and Sports NPU I: LO1309.

Keywords: beta titanium, cell growth, mesenchymal stem cells, titanium alloy, implant

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1705 Combined Effect of Roughness and Suction on Heat Transfer in a Laminar Channel Flow

Authors: Marzieh Khezerloo, Lyazid Djenidi

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Owing to wide range of the micro-device applications, the problems of mixing at small scales is of significant interest. Also, because most of the processes produce heat, it is needed to develop and implement strategies for heat removal in these devices. There are many studies which focus on the effect of roughness or suction on heat transfer performance, separately, although it would be useful to take advantage of these two methods to improve heat transfer performance. Unfortunately, there is a gap in this area. The present numerical study is carried to investigate the combined effects of roughness and wall suction on heat transfer performance of a laminar channel flow; suction is applied on the top and back faces of the roughness element, respectively. The study is carried out for different Reynolds numbers, different suction rates, and various locations of suction area on the roughness. The flow is assumed two dimensional, incompressible, laminar, and steady state. The governing Navier-Stokes equations are solved using ANSYS-Fluent 18.2 software. The present results are tested against previous theoretical results. The results show that by adding suction, the local Nusselt number is enhanced in the channel. In addition, it is shown that by applying suction on the bottom section of the roughness back face, one can reduce the thickness of thermal boundary layer, which leads to an increase in local Nusselt number. This indicates that suction is an effective means for improving the heat transfer rate (suction by controls the thickness of thermal boundary layer). It is also shown that the size and intensity of vortical motion behind the roughness element, decreased with an increasing suction rate, which leads to higher local Nusselt number. So, it can be concluded that by using suction, strategically located on the roughness element, one can control both the recirculation region and the heat transfer rate. Further results will be presented at the conference for coefficient of drag and the effect of adding more roughness elements.

Keywords: heat transfer, laminar flow, numerical simulation, roughness, suction

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1704 Development of Doctoral Education in Armenia (1990 - 2023)

Authors: Atom Mkhitaryan, Astghik Avetisyan

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We analyze the developments of doctoral education in Armenia since 1990 and the management process. Education and training of highly qualified personnel are increasingly seen as a fundamental platform that ensures the development of the state. Reforming the national institute for doctoral studies (aspirantura) is aimed at improving the quality of human resources in science, optimizing research topics in accordance with the priority areas of development of science and technology, increasing publication and innovative activities, bringing national science and research closer to the world level and achieving international recognition. We present a number of defended dissertations in Armenia during the last 30 years, the dynamics and the main trends of the development of the academic degree awarding system. We discuss the possible impact of reforming the system of training and certification of highly qualified personnel on the organization of third–level doctoral education (doctoral schools) and specialized / dissertation councils in Armenia. The results of the SWOT analysis of doctoral education and academic degree awarding processes in Armenia are shown. The article presents the main activities and projects aimed at using the advantages and strong points of the National Academy network in order to improve the quality of doctoral education and training. The paper explores the mechanisms of organizational, methodological and infrastructural support for research and innovation activities of doctoral students and young scientists. There are also suggested approaches to the organization of strong networking between research institutes and foreign universities for training and certification of highly qualified personnel. The authors define the role of ISEC in the management of doctoral studies and the establishment of a competitive third-level education for the sphere of research and development in Armenia.

Keywords: doctoral studies, academic degree, PhD, certification, highly qualified personnel, dissertation, research and development, innovation, networking, management of doctoral school

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1703 Hydrodynamics of Undulating Ribbon-fin and Its Application in Bionic Underwater Robot

Authors: Zhang Jun, Zhai Shucheng, Bai Yaqiang, Zhang Guoping

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The Gymnarchus Niioticus fish(GNF) cruises generally with high efficiency by undulating ribbon-fin propulsion while keeping its body for straight line. The swing amplitude of GNF fins is usually in 60° to 90°, and in normal state the amplitude is close to 90°, only in the control of hovering or swimming at very low speed, the amplitude is smaller (about 60°). It provides inspiration for underwater robot design. In the paper, the unsteady flow of undulating ribbon-fin propulsion is numerical simulated by the dynamic grid technique including spring-based smoothing model and local grid remeshing to adapt to the fin surface significantly deforming, and the swing amplitude of fin ray reaches 850. The numerical simulation method is validated by thrust experiments. The spatial vortex structure and its evolution with phase angle is analyzed. The propulsion mechanism is investigated by comprehensive analysis of the hydrodynamics, vortex structure, and pressure distribution on the fin surface. The numerical results indicates that there are mainly three kinds of vortexes, i.e. streamwise vortex, crescent vortex and toroidal vortex. The intensity of streamwise vortex is the strongest among all kinds of vortexes. Streamwise vortexes and crescent vortexes all alternately distribute on the two sides of mid-sagittal plane. Inside the crescent vortexes is high-speed flow, while outside is low-speed flow. The crescent vortexes mainly induce high-speed axial jet, which produces the primary thrust. This is hydrodynamic mechanism undulating ribbon-fin propulsion. The streamwise vortexes mainly induce the vertical jet, which generates the primary heave force. The effect on hydrodynamics of main geometry and movement parameters including wave length, amplitude and advanced coefficients is investigated. A bionic underwater robot with bilateral undulating ribbon-fins is designed, and its navigation performance and maneuverability are measured.

Keywords: bionic propulsion, mobile robot, underwater robot, undulating ribbon-fins

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1702 Sustainable Capacity Building on Tourism Management of Touristic Destinations in Ghana: The Case of James and Ussher Forts in the Accra Metropolis

Authors: Fiona Gibson

Abstract:

This study is on sustainable capacity building in tourism management of the touristic destination of forts and castles within the Accra Metropolis, of the Greater Accra Region of Ghana, notably, the Christianbough Castle, the James and Ussher Forts. These forts and castle mentioned above have a rich colonial historical past that emerged from the 17th century onwards on the Gulf Coast of Guinea of the West Africa Sub-Region. Unfortunately, apart from the Christianbough Castle, which used to be the seat of government until recently, the environment of James and Ussher Forts are in a deployable state of decay due to years of neglect. Jamestown and Usshertown fishing communities with historical colonial past of a rich touristic heritage sites are predominantly indigenous Gas who speak only the Ga language, one of the languages of the six local languages spoken in Ghana, as a medium for sustainable tourism management. The purpose of this study is to investigate the reasons for years of decay and neglect, using both qualitative and quantitative research approach for individual interviews, to develop a rich picture of life situational story of the people of James and Ussher Forts environs and finding solutions to their predicaments through internal generated funds for sustainability of tourism management within the communities. The study recommends nation-wide educational campaigns and programmes on culture of maintenance and management for sustainable tourism development and management at all historical heritage sites in the country, specifically with the aim of promoting tourism in Ghana, using the indigenous local languages. The study also recommends formal and informal education for the residents, especially the youth to help them learn skills, either through local training or the formal education and this call for collaboration between the government of Ghana and other local and international bodies.

Keywords: sustainable capacity building, tourism management, forts, castles

Procedia PDF Downloads 496
1701 Development of Fixture for Pipe to Pipe Friction Stir Welding of Dissimilar Materials

Authors: Aashutosh A. Tadse, Kush Mehta, Hardik Vyas

Abstract:

Friction Stir Welding is a process in which an FSW tool produces friction heat and thus penetrates through the junction and upon rotation carries out the weld by exchange of material within the 2 metals being welded. It involves holding the workpieces stiff enough to bear the force of the tool moving across the junction to carry out a successful weld. The weld that has flat plates as workpieces, has a quite simpler geometry in terms of fixture holding them. In the case of FSW of pipes, the pipes need to be held firm with the chucks and jaws according to the diameter of the pipes being welded; the FSW tool is then revolved around the pipes to carry out the weld. Machine requires a larger area and it becomes more costly because of such a setup. To carry out the weld on the Milling machine, the newly designed fixture must be set-up on the table of milling machine and must facilitate rotation of pipes by the motor being shafted to one end of the fixture, and the other end automatically rotated because of the rotating jaws held tight enough with the pipes. The set-up has tapered cones as the jaws that would go in the pipes thus holding it with the help of its knurled surface providing the required grip. The process has rotation of pipes with the stationary rotating tool penetrating into the junction. The FSW on pipes in this process requires a very low RPM of pipes to carry out a fine weld and the speed shall change with every combination of material and diameter of pipes, so a variable speed setting motor shall serve the purpose. To withstand the force of the tool, an attachment to the shaft is provided which will be diameter specific that will resist flow of material towards the center during the weld. The welded joint thus carried out will be proper to required standards and specifications. Current industrial requirements state the need of space efficient, cost-friendly and more generalized form of fixtures and set-ups of machines to be put up. The proposed design considers every mentioned factor and thus proves to be positive in the same.

Keywords: force of tool, friction stir welding, milling machine, rotation of pipes, tapered cones

Procedia PDF Downloads 114
1700 Attenuation of Amyloid beta (Aβ) (1-42)-Induced Neurotoxicity by Luteolin

Authors: Dona Pamoda W. Jayatunga, Veer Bala Gupta, Eugene Hone, Ralph N. Martins

Abstract:

Being a neurodegenerative disorder, Alzheimer’s disease (AD) affects a majority of the elderly demented worldwide. The key risk factors for AD are age, metabolic syndrome, allele status of APOE gene, head injuries and lifestyle. The progressive nature of AD is characterized by symptoms of multiple cognitive deficits exacerbated over time, leading to death within a decade from clinical diagnosis. However, it is revealed that AD originates via a prodromal phase that spans from one to few decades before symptoms first manifest. The key pathological hallmarks of AD brains are deposition of amyloid beta (Aβ) plaques and neurofibrillary tangles (NFT). However, the yet unknown etiology of the disease fails to distinguish mitochondrial dysfunction between a cause or an outcome. The absence of early diagnosis tools and definite therapies for AD have permitted recruits of nutraceutical-based approaches aimed at reducing the risk of AD by modulating lifestyle or be used as preventive tools during AD prodromal state before widespread neurodegeneration begins. The objective of the present study was to investigate beneficial effects of luteolin, a plant-based flavone compound, against AD. The neuroprotective effects of luteolin on amyloid beta (Aβ) (1-42)-induced neurotoxicity was measured using cultured human neuroblastoma BE(2)-M17 cells. After exposure to 20μM Aβ (1-42) for 48 h, the neuroblastoma cells exhibited marked apoptotic death. Co-treatment of 20μM Aβ (1-42) with luteolin (0.5-5μM) significantly protected the cells against Aβ (1-42)-induced toxicity, as assessed by the MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2(4sulfophenyl)-2H-tetrazolium, inner salt; MTS] reduction assay and the lactate dehydrogenase (LDH) cell death assay. The results suggest that luteolin prevents Aβ (1-42)-induced apoptotic neuronal death. However, further studies are underway to determine its protective mechanisms in AD including the activity against tau hyperphosphorylation and mitochondrial dysfunction.

Keywords: Aβ (1-42)-induced toxicity, Alzheimer’s disease, luteolin, neuroblastoma cells

Procedia PDF Downloads 150
1699 Gender Differences in the Impact and Subjective Interpretation of Childhood Sexual Abuse Survivors

Authors: T. Borja-Alvarez, V. Jiménez-Borja, M. Jiménez Borja, C. J. Jiménez-Mosquera

Abstract:

Research on child sexual abuse has predominantly focused on female survivors. This has resulted in less research looking at the particular context in which this abuse takes place for boys and the impact this abuse may have on male survivors. The aim of this study is to examine the sex and age of the perpetrators of child sexual abuse and explore gender differences in the impact along with the subjective interpretation that survivors attribute to these experiences. The data for this study was obtained from Ecuadorian university students (M = 230, F = 293) who reported sexual abuse using the ISPCAN Child Abuse Screening Tool Retrospective version (ICAST-R). Participants completed Horowitz's Impact of Event Scale (IES) and were also requested to choose among neutral, positive, and negative adjectives to describe these experiences. The results indicate that in the case of males, perpetrators were both males (adults =27%, peers =20%, relatives =10.3%, cousins =7.4%) and young females (girlfriends or ex-girlfriends =25.6%, neighborhood =20.7%, school =16.7%, cousins =15.3%, strangers =12.8%). In contrast, almost all females reported that adult males were the perpetrators (relatives =29.6%, neighborhood =11.9%, strangers =19.9%, family friends =9.7%). Regarding the impact of these events, significant gender differences emerged. More females (50%) than males (20%) presented symptoms of post-traumatic stress disorder (PTSD). Gender differences also surfaced in the way survivors interpret their experiences. Almost half of the male participants selected the word “consensual” followed by the words “normal”, “helped me to mature”, “shameful”, “confusing”, and “traumatic”. In contrast, almost all females chose the word “non-consensual” followed by the words “shameful”, “traumatic”, “scary”, and “confusing”. In conclusion, the findings of this study suggest that young females and adult males were the most common perpetrators of sexually abused boys whereas adult males were the most common perpetrators of sexually abused girls. The impact and the subjective interpretation of these experiences were more negative for girls than for boys. The factors that account for the gender differences in the impact and the interpretation of these experiences need further exploration. It is likely that the cultural expectations of sexual behaviors for boys and girls in Latin American societies may partially explain the differential impact in the way these childhood sexual abuse experiences are interpreted in adulthood. In Ecuador, as is the case in other Latin American countries, the machismo culture not only accepts but encourages early sexual behaviors in boys and negatively judges premature sexual behavior in females. The result of these different sexual expectations may be that sexually abused boys may re-define these experiences as “consensual” and “normal” in adulthood, even though these were not consensual at the time of occurrence. Future studies are needed to more deeply understand the different contexts of sexual abuse for boys and girls in order to analyze the long-term impact of these experiences.

Keywords: abuse, child, gender differences, sexual

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1698 An Assessment on Socio-Economic Impacts of Smallholder Eucalyptus Tree Plantation in the Case of Northwest Ethiopia

Authors: Mersha Tewodros Getnet, Mengistu Ketema, Bamlaku Alemu, Girma Demilew

Abstract:

The availability of forest products determines the possibilities for forest-based livelihood options. Plantation forest is a widespread economic activity in highland areas of the Amhara regional state, owing primarily to degradation and limited access to natural forests. As a result, tree plantation has become one of the rural livelihood options in the area. Therefore, given the increasing importance of smallholder plantations in highland areas of Amhara Regional States, the aim of this research was to evaluate the extent of smallholder plantations and their socio-economic impact. To address the abovementioned research, a sequential embedded mixed research design was employed. This qualitative and quantitative information was gathered from both primary and secondary sources. Primary data were collected from 385 sample households, which were chosen using a three-stage, multi-stage sampling method based on the Cochran sample size formula. Both descriptive and inferential statistics were used to analyze the data. Smallholder eucalyptus plantations in the study area were discovered to be common, and they are now part of the livelihood portfolio for meeting both household wood consumption and generating cash income. According to the PSM model's ATT results, income from selling farm forest products certainly contributes more to total household income, farm expenditure per cultivated land, and education spending than non-planter households. As a result, the government must strengthen plantation practices by prioritizing specific intervention areas while implementing measures to counteract the plantation's inequality-increasing effect through a variety of means, including progressive taxation.

Keywords: smallholder plantation, Eucalyptus, propensity score matching, average treatment effect and income

Procedia PDF Downloads 139
1697 A Comparative Study of Regional Climate Models and Global Coupled Models over Uttarakhand

Authors: Sudip Kumar Kundu, Charu Singh

Abstract:

As a great physiographic divide, the Himalayas affecting a large system of water and air circulation which helps to determine the climatic condition in the Indian subcontinent to the south and mid-Asian highlands to the north. It creates obstacles by defending chill continental air from north side into India in winter and also defends rain-bearing southwesterly monsoon to give up maximum precipitation in that area in monsoon season. Nowadays extreme weather conditions such as heavy precipitation, cloudburst, flash flood, landslide and extreme avalanches are the regular happening incidents in the region of North Western Himalayan (NWH). The present study has been planned to investigate the suitable model(s) to find out the rainfall pattern over that region. For this investigation, selected models from Coordinated Regional Climate Downscaling Experiment (CORDEX) and Coupled Model Intercomparison Project Phase 5 (CMIP5) has been utilized in a consistent framework for the period of 1976 to 2000 (historical). The ability of these driving models from CORDEX domain and CMIP5 has been examined according to their capability of the spatial distribution as well as time series plot of rainfall over NWH in the rainy season and compared with the ground-based Indian Meteorological Department (IMD) gridded rainfall data set. It is noted from the analysis that the models like MIROC5 and MPI-ESM-LR from the both CORDEX and CMIP5 provide the best spatial distribution of rainfall over NWH region. But the driving models from CORDEX underestimates the daily rainfall amount as compared to CMIP5 driving models as it is unable to capture daily rainfall data properly when it has been plotted for time series (TS) individually for the state of Uttarakhand (UK) and Himachal Pradesh (HP). So finally it can be said that the driving models from CMIP5 are better than CORDEX domain models to investigate the rainfall pattern over NWH region.

Keywords: global warming, rainfall, CMIP5, CORDEX, NWH

Procedia PDF Downloads 169
1696 Factors Affecting the Uptake of Modern Contraception Services in Oyo State, Nigeria

Authors: Folajinmi Oluwasina, Magbagbeola Dairo, Ikeoluwapo Ajayi

Abstract:

Contraception has proven to be an effective way of controlling fertility and spacing births. Studies have shown that contraception can avert the high-risk pregnancies and consequently reduce maternal deaths up to 32%. Uptake of modern contraception is promoted as a mechanism to address the reproductive health needs of men and women, as well as the crucial challenge of rapid population increase. A cross- sectional descriptive study using a two- stage systematic sampling technique was used to select 530 women of reproductive age out of 20,000 households. Respondents were interviewed using a semi-structured questionnaire. Knowledge was assessed on a 5 point score in which a score of ≤ 2 rated poor while perception was scored on 36 points score in which a score of ≤ 18 was rated low. Data were analyzed using descriptive statistics, Chi-square test and logistic regression at p< 0.05. There were 530 respondents. Age of respondents was 30.3 ±7.8 years, and 73.0% were married. About 90% had good knowledge of contraception while 60.8% had used contraceptives. The commonest source of information about contraception was mass media (72.8%). Minority (26.1%) obtained husbands approval before using contraceptive while 20.0% had used modern contraceptives before the first birth. Many (54.5%) of the respondents agreed that contraception helps in improving standard of living and 64.7% had good perception about contraception. Factors that hindered effective uptake of contraception services included poor service provider’s attitude (33.3%) and congestion at the service centers (4.5%). Respondents with nonuse of contraceptive before first birth are less likely to subsequently use contraceptives (OR= 0.324, 95% CI= 0.1-0.5). Husband approval of contraceptives use was the major determinant of women’s contraceptive use (OR = 3.4, 95% CI = 1.3-8.7). Respondents who had family planning centers not more than 5 kilometers walking distance to their residence did not significantly use contraception services (41.5%) more than 21.1% of those who had to take means of transportation to the service venues. This study showed that majority of the respondents were knowledgeable and aware of contraception services, but husband’s agreement on the use of modern contraceptives remains poor. Programmes that enhances husbands approval of modern contraception is thus recommended.

Keywords: contraception services, service provider’s attitude, uptake, husbands approval

Procedia PDF Downloads 365
1695 Use of PACER Application as Physical Activity Assessment Tool: Results of a Reliability and Validity Study

Authors: Carine Platat, Fatima Qshadi, Ghofran Kayed, Nour Hussein, Amjad Jarrar, Habiba Ali

Abstract:

Nowadays, smartphones are very popular. They are offering a variety of easy-to-use and free applications among which step counters and fitness tests. The number of users is huge making of such applications a potentially efficient new strategy to encourage people to become more active. Nonetheless, data on their reliability and validity are very scarce and when available, they are often negative and contradictory. Besides, weight status, which is likely to introduce a bias in the physical activity assessment, was not often considered. Hence, the use of these applications as motivational tool, assessment tool and in research is questionable. PACER is one of the free step counters application. Even though it is one of the best rated free application by users, it has never been tested for reliability and validity. Prior any use of PACER, this remains to be investigated. The objective of this work is to investigate the reliability and validity of the smartphone application PACER in measuring the number of steps and in assessing the cardiorespiratory fitness by the 6 minutes walking test. 20 overweight or obese students (10 male and 10 female) were recruited at the United Arab Emirate University, aged between 18 and 25 years old. Reliability and validity were tested in real life conditions and in controlled conditions by using a treadmill. Test-retest experiments were done with PACER on 2 days separated by a week in real life conditions (24 hours each time) and in controlled conditions (30 minutes on treadmill, 3km/h). Validity was tested against the pedometer OMRON in the same conditions. During treadmill test, video was recorded and steps numbers were compared between PACER, pedometer and video. The validity of PACER in estimating the cardiorespiratory fitness (VO2max) as part of the 6 minutes walking test (6MWT) was studied against the 20m shuttle running test. Reliability was studied by calculating intraclass correlation coefficients (ICC), 95% confidence interval (95%CI) and by Bland-Altman plots. Validity was studied by calculating Spearman correlation coefficient (rho) and Bland-Altman plots. PACER reliability was good in both male and female in real life conditions (p≤10-3) but only in female in controlled conditions (p=0.01). PACER was valid against OMRON pedometer in male and female in real life conditions (rho=0.94, p≤10-3 ; rho=0.64, p=0.01, in male and female respectively). In controlled conditions, PACER was not valid against pedometer. But, PACER was valid against video in female (rho=0.72, p≤10-3). PACER was valid against the shuttle run test in male and female (rho-=0.66, p=0.01 ; rho=0.51, p=0.04) to estimate VO2max. This study provides data on the reliability and viability of PACER in overweight or obese male and female young adults. Globally, PACER was shown as reliable and valid in real life conditions in overweight or obese male and female to count steps and assess fitness. This supports the use of PACER to assess and promote physical activity in clinical follow-up and community interventions.

Keywords: smartphone application, pacer, reliability, validity, steps, fitness, physical activity

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1694 Immigration in British Southern Cameroons from 2016 to 2020

Authors: Geraldine Ambe

Abstract:

Cameroon is a country in a country in Central Africa. Before the first World War, Germany colonized Cameroon, including some parts of Gabon, Chad, Nigeria, and the Central African Republic. After the war, the United Nations divided most of the colony into Britain and France. In 1960, Eastern Cameroon (‘La Republique du Cameroon’) gained its independence from France while British Southern Cameroons obtained its independence from Britain. The two entities agreed to live together as a federal state officially called the Federal Republic of Cameroon. In 1962, the name of the name of the country was changed from the Federal Republic of Cameroon to the United Republic of Cameroon, while the Prime Minister of Western Cameroon was moved to Yaounde. In 1984, President Paul Biya singlehandedly changed the name to the Republic of Cameroon, implying that Southern Cameroon is not recognized in the union again. From the words of Am Cohen, the two territories came together to form a federal government with one currency, one army, and one foreign policy like states in the United States of America. However, the name Republic of Cameroon (‘La Republique du Cameroun’) does not recognize BSC, and this is exactly what has been practiced: politics of exclusion and excessive centralization in Yaounde. In 2016, teachers and Lawyers started strikes to call the attention of the government on the inhalation of the English culture/people. They were greeted with guns, causing the radicalization of the youths. The civil society came together to form a union to address the issues facing the people, and the government took their leaders and sentenced them to live imprisonment. The consequence was a civil war with nobody to dialogue with. Out of Cameroon, more than half a million people from BSC have been taking dangerous trips through the air, land, and sea. In the jungles and the deserts, the snow of Europe, these people have been seen for the last 4 years. This paper will present some personalities, political fractions, and their stands of decentralization, federalism, and independence as the war continues. The paper will further look at the consequence of this crisis on migration in Central and Eastern Europe.

Keywords: British Southern Cameroons, decolonization, Second World War, dialogue, civil war, immigration

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1693 A Coupled Model for Two-Phase Simulation of a Heavy Water Pressure Vessel Reactor

Authors: D. Ramajo, S. Corzo, M. Nigro

Abstract:

A Multi-dimensional computational fluid dynamics (CFD) two-phase model was developed with the aim to simulate the in-core coolant circuit of a pressurized heavy water reactor (PHWR) of a commercial nuclear power plant (NPP). Due to the fact that this PHWR is a Reactor Pressure Vessel type (RPV), three-dimensional (3D) detailed modelling of the large reservoirs of the RPV (the upper and lower plenums and the downcomer) were coupled with an in-house finite volume one-dimensional (1D) code in order to model the 451 coolant channels housing the nuclear fuel. Regarding the 1D code, suitable empirical correlations for taking into account the in-channel distributed (friction losses) and concentrated (spacer grids, inlet and outlet throttles) pressure losses were used. A local power distribution at each one of the coolant channels was also taken into account. The heat transfer between the coolant and the surrounding moderator was accurately calculated using a two-dimensional theoretical model. The implementation of subcooled boiling and condensation models in the 1D code along with the use of functions for representing the thermal and dynamic properties of the coolant and moderator (heavy water) allow to have estimations of the in-core steam generation under nominal flow conditions for a generic fission power distribution. The in-core mass flow distribution results for steady state nominal conditions are in agreement with the expected from design, thus getting a first assessment of the coupled 1/3D model. Results for nominal condition were compared with those obtained with a previous 1/3D single-phase model getting more realistic temperature patterns, also allowing visualize low values of void fraction inside the upper plenum. It must be mentioned that the current results were obtained by imposing prescribed fission power functions from literature. Therefore, results are showed with the aim of point out the potentiality of the developed model.

Keywords: PHWR, CFD, thermo-hydraulic, two-phase flow

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1692 Multilingualism without a Dominant Language in the Preschool Age: A Case of Natural Italian-Russian-German-English Multilingualism

Authors: Legkikh Victoria

Abstract:

The purpose of keeping bi/multilingualism is usually a way to let the child speak two/three languages at the same level. The main problem which normally appears is a mixed language or a domination of one language. The same level of two or more languages would be ideal but practically not easily reachable. So it was made an experiment with a girl with a natural multilingualism as an attempt to avoid a dominant language in the preschool age. The girl lives in Germany and the main languages for her are Italian, Russian and German but she also hears every day English. ‘One parent – one language’ strategy was used since the beginning so Italian and Russian were spoken to her since her birth, English was spoken between the parents and when she was 1,5 it was added German as a language of a nursery. In order to avoid a dominant language, she was always put in international groups with activity in different languages. Even if it was not possible to avoid an interference of languages in this case we can talk not only about natural multilingualism but also about balanced bilingualism in preschool time. The languages have been developing in parallel with different accents in a different period. Now at the age of 6 we can see natural horizontal multilingualism Russian/Italian/German/English. At the moment, her Russian/Italian bilingualism is balanced. German vocabulary is less but the language is active and English is receptive. We can also see a reciprocal interference of all the three languages (English is receptive so the simple phrases are normally said correctly but they are not enough to judge the level of language interference and it is not noticed any ‘English’ mistakes in other languages). After analysis of the state of every language, we can see as a positive and negative result of the experiment. As a positive result we can see that in the age of 6 the girl does not refuse any language, three languages are active, she differentiate languages and even if she says a word from another language she notifies that it is not a correct word, and the most important are the fact, that she does not have a preferred language. As a prove of the last statement it is to be noticed not only her self-identification as ‘half Russian and half Italian’ but also an answer to the question about her ‘mother tongue’: ‘I do not know, probably, when I have my own children I will speak one day Russian and one day Italian and sometimes German’. As a negative result, we can notice that not only a development of all the three languages are a little bit slower than it is supposed for her age but since she does not have a dominating language she also does not have a ‘perfect’ language and the interference is reciprocal. In any case, the experiment shows that it is possible to keep at least two languages without a preference in a pre-school multilingual space.

Keywords: balanced bilingualism, language interference, natural multilingualism, preschool multilingual education

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1691 Establishment of Decision Support Center for Managing Natural Hazard Consequence in Kuwait

Authors: Abdullah Alenezi, Mane Alsudrawi, Rafat Misak

Abstract:

Kuwait is faced with a potentially wide and harmful range of both natural and anthropogenic hazardous events such as dust storms, floods, fires, nuclear accidents, earthquakes, oil spills, tsunamis and other disasters. For Kuwait can be highly vulnerable to these complex environmental risks, an up-to-date and in-depth understanding of their typology, genesis, and impact on the Kuwaiti society is needed. Adequate anticipation and management of environmental crises further require a comprehensive system of decision support to the benefit of decision makers to further bridge the gap between (technical) risk understanding and public action. For that purpose, the Kuwait Institute for Scientific Research (KISR), intends to establish a decision support center for management of the environmental crisis in Kuwait. The center will support policy makers, stakeholders and national committees with technical information that helps them efficiently and effectively assess, monitor to manage environmental disasters using decision support tools. These tools will build on state of the art quantification and visualization techniques, such as remote sensing information, Geographical Information Systems (GIS), simulation and prediction models, early warning systems, etc. The center is conceived as a central facility which will be designed, operated and managed by KISR in coordination with national authorities and decision makers of the country. Our vision is that by 2035 the center will be recognized as a leading national source of scientific advice on national risk management in Kuwait and build unity of effort among Kuwaiti’s institutions, government agencies, public and private organizations through provision and sharing of information. The project team now focuses on capacity building through upgrading some KISR facilities manpower development, build strong collaboration with international alliance.

Keywords: decision support, environment, hazard, Kuwait

Procedia PDF Downloads 313
1690 Exploring Tree Growth Variables Influencing Carbon Sequestration in the Face of Climate Change

Authors: Funmilayo Sarah Eguakun, Peter Oluremi Adesoye

Abstract:

One of the major problems being faced by human society is that the global temperature is believed to be rising due to human activity that releases carbon IV oxide (CO2) to the atmosphere. Carbon IV oxide is the most important greenhouse gas influencing global warming and possible climate change. With climate change becoming alarming, reducing CO2 in our atmosphere has become a primary goal of international efforts. Forest landsare major sink and could absorb large quantities of carbon if the trees are judiciously managed. The study aims at estimating the carbon sequestration capacity of Pinus caribaea (pine)and Tectona grandis (Teak) under the prevailing environmental conditions and exploring tree growth variables that influencesthe carbon sequestration capacity in Omo Forest Reserve, Ogun State, Nigeria. Improving forest management by manipulating growth characteristics that influences carbon sequestration could be an adaptive strategy of forestry to climate change. Random sampling was used to select Temporary Sample Plots (TSPs) in the study area from where complete enumeration of growth variables was carried out within the plots. The data collected were subjected to descriptive and correlational analyses. The results showed that average carbon stored by Pine and Teak are 994.4±188.3 Kg and 1350.7±180.6 Kg respectively. The difference in carbon stored in the species is significant enough to consider choice of species relevant in climate change adaptation strategy. Tree growth variables influence the capacity of the tree to sequester carbon. Height, diameter, volume, wood density and age are positively correlated to carbon sequestration. These tree growth variables could be manipulated by the forest manager as an adaptive strategy for climate change while plantations of high wood density speciescould be relevant for management strategy to increase carbon storage.

Keywords: adaptation, carbon sequestration, climate change, growth variables, wood density

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1689 Shear Strength Parameters of an Unsaturated Lateritic Soil

Authors: Jeferson Brito Fernades, Breno Padovezi Rocha, Roger Augusto Rodrigues, Heraldo Luiz Giacheti

Abstract:

The geotechnical projects demand the appropriate knowledge of soil characteristics and parameters. The determination of geotechnical soil parameters can be done by means of laboratory or in situ tests. In countries with tropical weather, like Brazil, unsaturated soils are very usual. In these soils, the soil suction has been recognized as an important stress state variable, which commands the geo-mechanical behavior. Triaxial and direct shear tests on saturated soils samples allow determine only the minimal soil shear strength, in other words, no suction contribution. This paper briefly describes the triaxial test with controlled suction as well as discusses the influence of suction on the shear strength parameters of a lateritic tropical sandy soil from a Brazilian research site. In this site, a sample pit was excavated to retrieve disturbed and undisturbed soil blocks. The samples extracted from these blocks were tested in laboratory to represent the soil from 1.5, 3.0 and 5.0 m depth. The stress curves and shear strength envelopes determined by triaxial tests varying suction and confining pressure are presented and discussed. The water retention characteristics on this soil complement this analysis. In situ CPT tests were also carried out at this site in different seasons of the year. In this case, the soil suction profile was determined by means of the soil water retention. This extra information allowed assessing how soil suction also affected the CPT data and the shear strength parameters estimative via correlation. The major conclusions of this paper are: the undisturbed soil samples contracted before shearing and the soil shear strength increased hyperbolically with suction; and it was possible to assess how soil suction also influenced CPT test data based on the water content soil profile as well as the water retention curve. This study contributed with a better understanding of the shear strength parameters and the soil variability of a typical unsaturated tropical soil.

Keywords: site characterization, triaxial test, CPT, suction, variability

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1688 Report of a Realistic Simulation Training in Using Bougie Guide for Endotracheal Intubation

Authors: Cleto J. Sauer Jr., Rita C. Sauer, Chaider G. Andrade, Dóris F. Rabelo

Abstract:

Some patients with COVID-19 disease and difficult airway characteristics undergo to endotracheal intubation (ETI) procedure. The tracheal introducer, known as the bougie guide, can aid ETI in patients with difficult airway pattern. Realistic simulation (RS) is a methodology utilized for healthcare professionals training. To improve skills in using the bougie guide of physicians from Recôncavo da Bahia region in Brazil, during COVID-19 outbreak, RS training was carried out. Simulated scenario included the Nasco Lifeform realistic simulator for ETI and a bougie guide introducer. Training was a capacitation program organized by the Health Department of Bahia State. Objective: To report effects in participants´ self-confidence perception for using bougie guide after a RS based training. Methods: Descriptive study, secondary data extracted from questionnaires. Priority workplace and previous knowledge about bougie were reported on a preparticipation formulary. Participants also completed pre- and post-training qualitative self-assessment (10-point Likert scale) regarding to self-confidence in using bougie guide. Distribution analysis for qualitative data was performed with Wilcoxon Signed Rank Test, and self-confidence increase analysis in frequency contingency tables with Fisher's exact test. Results: From May to June 2020 a total of 36 physicians participated of training, 25 (69%) from primary care setting, 32 (89%) with no previous knowledge about the bougie guide utilization. For those who had previous knowledge about bougie pre-training self-confidence median was 6,5, and 2 for participants who had not. In overall there was an increase in self-confidence median for bougie utilization. Median (variation) before and after training was 2.5 (1-7) vs. 8 (4-10) (p <0.0001). Among those who had no previous knowledge about bougie (n = 32) an increase in self-confidence greater than 3 points for bougie utilization was reported by 31 vs. 1 participants (p = 0.71). Conclusions: Most of participants had no previous knowledge about using the bougie guide. RS training contributed to self-confidence increase for using bougie for ETI procedure. RS methodology can contribute for training in using the bougie guide for ETI procedure during COVID-19 outbreak.

Keywords: bougie, confidence, COVID-19, endotracheal intubation, realistic simulation

Procedia PDF Downloads 144