Search results for: good modelling practice

Authors: Zeineb Kesentini, Abderrahim El Mahi, Jean Luc Rebiere, Rachid El Guerjouma, Moez Beyaoui, Mohamed Haddar

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Industries’ attention has been drawn to green and sustainable materials as a result of the present energy deficit and environmental damage. Sandwiches formed of auxetic structures made up of periodic cells are also being investigated by industry. Several tests have emphasized the exceptional properties of these materials. In this study, the sandwich's core is a one-cell auxetic core. Among plant fibers, flax fibers are chosen because of their good mechanical properties comparable to those of glass fibers. Poly (lactic acid) (PLA), as a green material, is available from starch, and its production process requires fewer fossil resources than petroleum-based plastics. A polylactic acid (PLA) reinforced with flax fiber filament was employed in this study. The manufacturing process used to manufacture the test specimens is 3D printing. The major drawback of a 100% bio-based material is its low resistance to moisture absorption. In this study, a sandwich based on PLA / flax with an auxetic core is characterized statically for different periods of immersion in water. Bending tests are carried out on the composite sandwich for three immersion time. Results are compared to those of non immersed specimens. It is found that non aged sandwich has the ultimate bending stiffness.

Keywords: auxetic, bending tests, biobased composite, sandwich structure, 3D printing

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Authors: Sudarshan Kalsulkar, Sunil S. Bhagwat

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Biosorption is a physiochemical process that occurs naturally in certain biomass which allows it to passively concentrate and bind contaminants onto its cellular structure. Activated carbons (AC) are one such efficient biosorbents made by utilizing lignocellulosic materials from agricultural waste. Steam activated carbon (AC) was synthesized from Barley husk. Its synthesis parameters of time and temperature were optimized. Its physico-chemical properties like density, surface area, pore volume, Methylene blue and Iodine values were characterized. BET surface area was found to be 42 m²/g. Batch Adsorption tests were carried out to determine the maximum adsorption capacity (qmax) for various metal ions. Cd+2 48.74 mg/g, Pb+2 19.28 mg/g, Hg+2 39.1mg/g were the respective qmax values. pH and time were optimized for adsorption of each ion. Column Adsorptions were carried for each to obtain breakthrough data. Microbial adsorption was carried using E. coli K12 strain. 78% reduction in cell count was observed at operating conditions. Thus the synthesized Barley husk AC can be an economically feasible replacement for commercially available AC prepared from the costlier coconut shells. Breweries and malting industries where barley husk is a primary waste generated on a large scale can be a good source for bulk raw material.

Keywords: activated carbon, Barley husk, biosorption, decontamination, heavy metal removal, water treatment

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Authors: Angela Mathias Kavishe

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Sexual harassment directed at women is reported in many societies, including in Tanzania. The advent of ICT technology, especially in universities, seems to aggravate the situation by extending harassment to cyberspace in various forms, including cyberstalking. Evidence shows that online violence is more dangerous than physical one due to the ability to access multiple private information, attack many victims, mask the perpetrator's identity, suspend the threat for a long time and spread over time and space. The study aimed to measure the magnitude of cyber harassment in Tanzanian higher learning institutions and to assess institutional sensitivity to ICT-mediated gender-based violence. It was carried out in 4 higher learning institutions in Tanzania: Mwalimu Nyerere Memorial Academy and Institute of Finance Management in Dar es Salaam and SAUT, and the University of Dodoma, where a survey questionnaire was distributed to 400 students and 40 key informants were interviewed. It was found that in each institution, the majority of female students experienced online harassment on social media perpetrated by ex-partners, male students, and university male teaching staff. The perpetrators compelled the female students to post nude pictures, have sexual relations with them, or utilize the posted private photographs to force female students to practice online or offline sexual relations. These threats seem to emanate from social-cultural beliefs about the subordinate position of women in society and that women's bodies are perceived as sex objects. It is therefore concluded that cyberspace provides an alternative space for perpetrators to exercise violence towards women.

Keywords: cyberstalking, embodiment, gender-based violence, internet

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Authors: Kosutic Milenko, Filipovic Jelena

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Cereals constitute the staple food of the human race. In accordance with the modern nutritionist opinions, cereal products, flakes and snack products are the most common foods in the daily diet, such as ready to eat breakfast cereal, flakes, and snacks. Extrusion technology makes it possible to apply different sources of ingredients for the enrichment of cereal-based flakes or snacks products. Substances with strong antioxidant properties such as wild oregano have a positive impact on human health, therefore attracting the attention of scientists, consumers and food industry experts. This paper investigates the effects of simultaneous addition of dry residue of wild oregano (0.5% and 1%), on the physical and colour properties of corn flakes to obtain new products with altered nutritional properties. Post-hoc Tukey’s HSD test at 95% confidence limit showed significant differences between various samples. Addition of dry residue wild oregano positively influenced physical characteristics (decreased bulk density 30.2%, increased expansion rate 44.9%), influenced of decrease hardness 38.1% and work of compression 40.3% also significantly change the color of flakes product. Presented data point that investigated corn flakes is a new product with good physical and sensory properties due to higher level of dry residue of wild oregano.

Keywords: flakes product, wild oregano, phisical properties, colour, sensory properties

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Authors: Estefanya Vazquez-Casaubon, Veroline Cauberghe, Dieneke Van de Sompel, Hayley Pearce

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Working together to reduce the anthropogenic impact should be a collective action, including effort within the household. In the matter, children are considered to have an important role in influencing the household to reduce the environmental impact through reversed socialization where children motivate and increase the concern of the parents towards environmental protection. Previous studies reveal that communication between parents and kids is key for effective reversed socialization. However, multiple barriers have been identified in the literature, such as the acceptance of the influence from the kids, the properties of the communication, among other factors. Based on the previous evidence, the present study aims to assess barriers and facilitators of communication at the household level that have an impact on reversed socialization. More precisely, the study examines how parents’ climate change coping strategy (problem-focused, meaning-focused, disregarding) influences the valence and the type of the communication related to climate change, and eventually the extent to which they report their beliefs and behaviours to be influenced by the pro-environmental perspectives of their children; i.e. reversed socialization. Via an online survey, 723 Belgian parents self-reported on communication about environmental protection and risk within their household (such as the frequency of exchange about topics related to climate change sourced from school, the household rules, imparting knowledge to the children, and outer factors like media or peer pressure, the emotional valence of the communication), their perceived socialization, and personal factors (coping mechanisms towards climate change). The results, using structural equation modelling, revealed that parents applying a problem-solving coping strategy related to climate change, appear to communicate more often in a positive than in a negative manner. Parents with a disregarding coping style towards climate change appear to communicate less often in a positive way within the household. Parents that cope via meaning-making of climate change showed to communicate less often in either a positive or negative way. Moreover, the perceived valence of the communication (positive or negative) influenced the frequency and type of household communication. Positive emotions increased the frequency of the communication overall. However, the direct effect of neither of the coping mechanisms on the reversed socialization was significant. High frequency of communication about the media, environmental views of the household members among other external topics had a positive impact on the perceived socialization, followed by discussions school-related; while parental instructing had a negative impact on the perceived socialization. Moreover, the frequency of communication was strongly affected by the perceived valence of the communication (positive or negative). The results go in line with previous evidence that a higher frequency of communication facilitates reversed socialization. Hence the results outstand how the coping mechanisms of the parents can be either a facilitator when they cope via problem-solving, while parents that disregard might avert frequent communication about climate change at the household.

Keywords: communication, parents’ coping mechanisms, environmental protection, household, perceived socialization

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Authors: Georgiana Ciobotaru

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The experience of exile is a defining one for the mittleeuropean writers, which is also the generator of an identity discourse manifested in the plan of fiction. In exile, the authors often build their marginality in opposition to that deserted mundi center. The Polish Gombrowicz carried out his existence, for more than twenty-three years, in a geographical exile, distancing himself from his country, and, from a cultural point of view, the writing meant a possibility of escape, of plunge into a literary exile that often constituted a way of conditioning the practice of writers. He opted for one of the attitudes that a writer in exile may have, namely he preferred to continue speaking Polish, although he was far from his homeland, turning to the public in his homeland, his entire literary creation in exile being promoted through Kulturia, the Paris-based immigration magazine. The problem of exile must be constantly related to three essential aspects, namely: territory, identity and language. The exile, both the writer and his characters, displays a characteristic attitude towards the abandoned land, but also towards the adoptive, towards the mother tongue, but also towards the idiom encountered, thus proving an original manner in terms of how it asserts, de-builds or re-builds its identity. In these texts written after leaving Poland, a series of open works by Trans-Atlantic, Gombrowicz assumes and internalizes the inadequacy between his self and the reality outside to make it the principle of his perception of the world. The expression of marginality that characterized the texts developed when the writer was still in Poland seems to acquire a certain coherence against the background of a logic imposed on the new experience, namely that of exile. Texts created during his exile in Argentina appear in a different context, in other words, in a situation of inadequacy towards the world: ignorance of the language, poverty, isolation that characterizes especially the first years spent there. This study aims to highlight how the Polish author de-builds and reconstructs his Mittel-European identity profile through language.

Keywords: discourse, exile, identity, immigration

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Authors: Mohd Ritzman Abdul Karim, Zhaohui Huang

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A current focus in seismic engineering practice is the development of seismic design approach that focuses on the performance-based design. Performance-based design aims to design the structures to achieve specified performance based on the damage limit states. This damage limit is more restrictive limit than life safety and needs to be carefully estimated to avoid damage in piers due to failure in transverse reinforcement. In this paper, a different perspective of damage limit states has been explored by integrating two damage control material limit state, concrete and reinforcement by introduced parameters such as expected yield stress of transverse reinforcement where peak tension strain prior to bar buckling is introduced in a recent study. The different perspective of damage limit states with modified yield displacement and the modified plastic-hinge length is used in order to predict damage-control target displacement for reinforced concreate (RC) bridge pier. Three-dimensional (3D) finite element (FE) model has been developed for estimating damage target displacement to validate proposed damage limit states. The result from 3D FE analysis was validated with experimental study found in the literature. The validated model then was applied to predict the damage target displacement for RC bridge pier and to validate the proposed study. The tensile strain on reinforcement and compression on concrete were used to determine the predicted damage target displacement and compared with the proposed study. The result shows that the proposed damage limit states were efficient in predicting damage-control target displacement consistent with FE simulations.

Keywords: damage-control target displacement, damage limit states, reinforced concrete bridge pier, yield displacement

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Authors: Nattawit Thiapairat

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Multiple diseases have been linked to excessive levels of free radicals, which cause tissue or cell damage as a result of oxidative stress. Many plants are sources of high antioxidant activity. Derris scandens has a high amount of phenolic and flavonoid contents which demonstrated good biological activities. This study focused on the antioxidant activity of polyphenols extracted from D. scandens. This study performs total flavonoids content and various antioxidant assays, which were 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity assays. The total flavonoid content of D. scandens extract was determined and expressed as quercetin equivalents (QE)/g measured by the aluminum chloride colorimetric method. The antioxidant activity of D. scandens extract was also determined by DPPH and ABTS assays. In the DPPH assay, vitamin C was used as a positive control, whereas Trolox was used as a positive control in the ABTS assay. The half-maximal inhibitory concentration (IC50) values for D. scandens extract from DPPH and ABTS assays were 41.79 μg/mL ± 0.783 and 29.42 μg/mL ± 0.890, respectively, in the DPPH assay. To conclude, D. scandens extract consists of a high amount of total phenolic content, which exhibits a significant antioxidant activity. However, further investigation regarding antioxidant activity such as SOD, ROS, and RNS scavenging assays and in vivo experiments should be performed.

Keywords: ABTS assay, antioxidant activity, Derris scandens, DPPH assays, total flavonoid content

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Authors: Aline Fernandes Barata, Adriana Sansão Fontes

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The overvaluation of the use of automobile has detrimentally affected the importance of pedestrians within the city and consequently its public spaces. As a way of treating contemporary urban paradigms, Tactical Urbanism aims to recover and activate spaces through fast and easily-applied actions that demonstrate the possibility of large-scale and long-term changes in cities. Tactical interventions have represented an important practice of redefining public spaces and urban mobility. The concept of Active Transportation coheres with the idea of sustainable urban mobility, characterizing the means of transportation through human propulsion, such as walking and cycling. This paper aims to debate the potential of Tactical Urbanism in promoting Active Transportation by revealing opportunities of transformation in the urban space of contemporary cities through initiatives that promote the protection and valorization of the presence of pedestrians and cyclists in cities, and that subvert the importance of motorized vehicles. In this paper, we present the character of these actions in two different ways: when they are used as tests for permanent interventions and when they have pre-defined start and end periods. Using recent initiatives to illustrate, we aim to discuss the role of small-scale actions in promoting and incentivizing a more active, healthy, sustainable and responsive urban way of life, presenting how some of them have developed through public policies. For that, we will present some examples of tactical actions that illustrate the encouragement of Active Transportation and trials to balance the urban opportunities for pedestrians and cyclists. These include temporary closure of streets, the creation of new alternatives and more comfortable areas for walking and cycling, and the subversion of uses in public spaces where the usage of cars are predominant.

Keywords: tactical urbanism, active transportation, sustainable mobility, non-motorized means

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Authors: Alexandra Monteiro, K. Bousson, Fernando J. O. Moreira, Ricardo Reis

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Fixed-wing flying vehicles are usually controlled by means of control surfaces such as elevators, ailerons, and rudders. The failure of these systems may lead to severe or even fatal crashes. These failures resulted in increased popularity for research activities on propulsion control in the last decades. The present work deals with a hybrid control architecture in which the propulsion-controlled vehicle maintains its traditional control surfaces, addressing the issue of robust lateral-directional dynamics control. The challenges stem from the parameter uncertainties in the stability and control derivatives and some unknown terms in the flight dynamics model. Two approaches are implemented and tested: linear quadratic regulation with robustness characteristics and H∞ control. The problem is centered on roll-yaw controller design with full state-feedback, which is able to deal with a standalone propulsion control mode as well as a hybrid mode combining both propulsion control and conventional control surface concepts while maintaining the original flight maneuverability characteristics. The results for both controllers emphasized very good control performances; however, the H∞ controller showed higher stabilization rates and robustness albeit with a slightly higher control magnitude than using the linear quadratic regulator.

Keywords: robust propulsion control, h-infinity control, lateral-directional flight dynamics, parameter uncertainties

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Authors: Wong Seng Yue

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Game dynamics and game mechanics are the two main components that used in gamification to engage and encourage students to learn. The advantages of gamified classroom are engaging students, increasing students interest, preserving students focus and remain a positive behaviour. However, the empirical studies on gamification are still at early stage, especially the effectiveness of various gamification components have not been evaluated. Thus, this study is aimed to conduct a user experience (UX) evaluation on gamified classroom through Prezi, which focused on learning experience, gaming experience, adaptivity, and gameplay experience. This study is a further study extended from the previous exploratory study to explore more on UX of gamified classroom via Prezi by interview. A focus group study, which involves 22 students from a foundation course has been conducted for the study. Besides the empirical data from the previous study, this focus group study has significantly found that 90.9% respondents show their positive perceptions on gaming experience via Prezi. They are interested, feel fresh, good, and highly motivated of the contents of Prezi. 95.5% participants have had a positive learning experience from the gamified classroom via Prezi, which can engage them, made them concentrate on learning and easy to remember what they have learned if compared to the traditional classroom slides. The adaptivity of the gamified classroom also high due to its zooming user interface, narrative, rewards and engagement features. This study has uncovered on how far the impact of gamification components in the classroom, especially UX that implemented in gamified classroom.

Keywords: user experience (UX), gamification, gamified classroom, Prezi

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Authors: Prih Bukhari

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The purpose of the proposed paper is to determine if the perception of online advertisement formed due to attitude and belief vary among two different countries or not. Specifically, it seeks to find out how people from China and Pakistan perceive online advertisement. Public attitude and belief towards advertising have been a focus of attention to explore a path to a better strategy of advertising. The ‘belief’ factor was analyzed through 4 items, i.e., product information, entertainment, and increase in economy’ whereas, the ‘attitude’ factor was analyzed thorough questions based on 4 items, i.e. ‘overall, I consider online advertising a good thing’; 'overall, I like online advertising’; ‘'I consider online advertising very essential’; and 'I would describe my overall attitude toward online advertising very favorably’. As such, it provides theoretical basis to explain similarities and differences of beliefs and attitude towards advertising across the two countries. Given its mixed method approach, both quantitative and qualitative method is used to carry out research. A questionnaire-based survey and focus group interviews were conducted. The sample size was of 500 participants. For analysis survey copies were then collected from which 497 were received whereas focus group interviews were collected from both nations. The findings showed that the belief factor among both countries had no significant relation with the perception of online advertisement. However, the attitude had a significant relation with the perception about online advertisement. Also it was observed that despite of different backgrounds, perception about online advertisement based on beliefs and attitude were found largely to be similar. Implications and future studies are provided.

Keywords: attitude, belief, online advertisement, perception

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Authors: Dan Han, Yukun Zhang, Jie Zheng, Rui Zhang

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Making full use of space along transportation infrastructure to develop renewable energy sources, especially solar energy resources, has become a research focus in relevant fields. In recent years, relevant international researches can be classified into three stages of theoretical and technical exploration, exploratory practice as well as planning implementation. Compared with traditional solar energy development mode, the development of solar energy resources in places along the transportation infrastructure has special advantages, which can also bring forth new opportunities for the development of green transportation. 'Road Integrated Photovoltaic', a development model of combining transport and new energy, has been actively studied and applied in developed countries, but it was still in its infancy in China. 'New Silk Road Economic Belt' has great advantage to carry out the 'Road Integrated Photovoltaic' because of the rich solar energy resources in its path, the shortages of renewable energy, the constraints of agricultural land and other reasons. Especially the massive amount of construction of transportation infrastructure brought by Silk Road Economic Belt, large area of developable land along the transportation line will be generated. Abundant solar energy recourses along the Silk Road will provide extremely superb practical opportunities to the land development along transportation infrastructure. We take PVsyst, GIS and Google map software for simulation of its potential by taking Lan-Xin Railway as an example, so potential electrical energy generation can be quantified and further analyzed. Research of 'New Silk Road Economic Belt' combined with 'Road Integrated Photovoltaic' is a creative development for the along transport and energy infrastructure. It not only can make full use of solar radiation and land in its path, but also bring more long-term advantages and benefits.

Keywords: land use, silk road economic belt, solar energy, transportation infrastructure

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Authors: Juan Carlos Rubio Romero, Francico Salguero Caparros, Virginia Herrera-Pérez

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No one is in the slightest doubt about the high levels of risk involved in work in the construction industry. They are even higher in structural construction work. The Critical Decision Method (CDM) is a semi-structured interview technique that uses cognitive tests to identify the different disturbances that workers have to deal with in their work activity. At present, the vision of safety focused on daily performance and things that go well for safety and health management is facing the new paradigm known as Resilience Engineering. The aim of this study has been to describe the variability in formwork labour on concrete structures in the construction industry and, from there, to find out the resilient attitude of workers to unexpected events that they have experienced during their working lives. For this purpose, a series of semi-structured interviews were carried out with construction employees with extensive experience in formwork labour in Spain by applying the Critical Decision Method. This work has been the first application of the Critical Decision Method in the field of construction and, more specifically, in the execution of structures. The results obtained show that situations categorised as unthought-of are identified to a greater extent than potentially unexpected situations. The identification during these interviews of both expected and unexpected events provides insight into the critical decisions made and actions taken to improve resilience in daily practice in this construction work. From this study, it is clear that it is essential to gain more knowledge about the nature of the human cognitive process in work situations within complex socio-technical systems such as construction sites. This could lead to a more effective design of workplaces in the search for improved human performance.

Keywords: resilience engineering, construction industry, unthought-of situations, critical decision method

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Authors: Tolga Arda Eraslan

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The quality of the indoor environment is significant to occupants’ health, comfort, and productivity, as Covid-19 spread throughout the world, people started spending most of their time indoors. Since buildings are getting bigger, mechanical ventilation systems are widely used where natural ventilation is insufficient. Four primary tasks of a ventilation system have been identified indoor air quality, comfort, contamination control, and energy performance. To fulfill such requirements, air diffusers, which are a part of the ventilation system, have begun to enter our lives in different airflow distribution systems. Detailed observations are needed to assure that such devices provide high levels of comfort effectiveness and energy efficiency. This study addresses these needs. The objective of this article is to observe air characterizations of different air diffusers at different angles and their effect on people by the thermal comfort model in CFD simulation and to validate the outputs with the help of data results based on a simulated office room. Office room created to provide validation; Equipped with many thermal sensors, including head height, tabletop, and foot level. In addition, CFD simulations were carried out by measuring the temperature and velocity of the air coming out of the supply diffuser. The results considering the flow interaction between diffusers and surroundings showed good visual illustration.

Keywords: computational fluid dynamics, fanger’s model, predicted mean vote, thermal comfort

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Authors: Panwasn Mahalawalert

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The objective of this study was to meta-evaluation of Master Degree theses in Science Program of Evaluation Methodology at Srinakharinwirot University, published during 2008-2011. This study was summative meta-evaluation that evaluated all theses of Master Degree in Science Program of Evaluation Methodology. Data were collected using the theses characteristics recording form and the evaluation meta-evaluation checklist. The collected data were analyzed by two parts: 1) Quantitative data were analyzed by descriptive statistics presented in frequency, percentages, mean, and standard deviation and 2) Qualitative data were analyzed by content analysis. The results of this study were found the theses characteristics was results revealed that most of theses were published in 2011. The largest group of theses researcher were female and were from the government office. The evaluation model of all theses were Decision-Oriented Evaluation Model. The objective of all theses were evaluate the project or curriculum. The most sampling technique were used the multistage random sampling technique. The most tool were used to gathering the data were questionnaires. All of the theses were analysed by descriptive statistics. The meta-evaluation results revealed that most of theses had fair on Utility Standards and Feasibility Standards, good on Propriety Standards and Accuracy Standards.

Keywords: meta-evaluation, evaluation, master degree theses, Srinakharinwirot University

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Authors: Jelili Kunle Adedeji, Toeb Akorede Akinbola

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The problem of vehicle mishap as a result of miscalculation, recklessness, or malfunction of some part in a vehicle is acknowledged to be a global issue. In most of the cases, it results into death or life injuries, all over the world; the issue becomes a nightmare to the stakeholders on how to curb mishaps on our roads due to these endemic factors. Hence this research typically examined the design of a device, specifically for learners that can lead to a society of intelligent vehicles (traffic) without withdrawing the driving authority from them, unlike pre-existing systems. Though ILASS shears a lot of principle with existing advance drivers assistance systems, yet there are two fundamental differences between ILASS system and existing systems. Firstly ILASS is meant to accept continuous input from the throttle at all time such that the devices will not constraint the driving process unnecessarily and ensure a change of speed at any point in time. Secondly, it made use of a variable threshold distance between the host vehicle and front vehicle which can be set by the host driver under the constraint of road maintenance agency, who communicates the minimum possible threshold for a different lane to the host vehicle. The results obtained from the simulation of the ILASS system concluded that ILASS is a good solution to road accidents, particularly road accident which occurs as a result of driving at high speed.

Keywords: front-vehicle, host-speed, threshold-distance, ILASS

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Authors: Rama Krishna Supramanian, Marzuki Isahak, Noran Naqiah Hairi

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Noise-induced hearing loss (NIHL) is one of the highest recorded occupational diseases, despite being preventable. Hearing Conservation Program (HCP) is designed to protect workers hearing and prevent them from developing hearing impairment due to occupational noise exposures. However, there is still a lack of evidence regarding the effectiveness of this program. The purpose of this study was to determine the effectiveness of a Hearing Conservation Program (HCP) in preventing or reducing audiometric threshold changes among vector control workers. This study adopts a cluster randomized controlled trial study design, with district health offices as the unit of randomization. Nine district health offices were randomly selected and 183 vector control workers were randomized to intervention or control group. The intervention included a safety and health policy, noise exposure assessment, noise control, distribution of appropriate hearing protection devices, training and education program and audiometric testing. The control group only underwent audiometric testing. Audiometric threshold changes observed in the intervention group showed improvement in the hearing threshold level for all frequencies except 500 Hz and 8000 Hz for the left ear. The hearing threshold changes range from 1.4 dB to 5.2 dB with largest improvement at higher frequencies mainly 4000 Hz and 6000 Hz. Meanwhile for the right ear, the mean hearing threshold level remained similar at 4000 Hz and 6000 Hz after 3 months of intervention. The Hearing Conservation Program (HCP) is effective in preserving the hearing of vector control workers involved in fogging activity as well as increasing their knowledge, attitude and practice towards noise-induced hearing loss (NIHL).

Keywords: adult, hearing conservation program, noise-induced hearing loss, vector control worker

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Authors: Stephen Eyije Abechi, Casimir Emmanuel Gimba, Zaharaddeen Nasiru Garba, Sani Shamsudeen, David Ebuka Authur

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The mechanisms of corrosion inhibition of mild steel in acid medium using Acalypha chamaedrifolia leaves extract as potential green inhibitor were investigated. Gravimetric (weight loss) technique was used for the corrosion studies. Mild steel coupons of 2cm × 1cm × 0.27 cm dimensions were exposed for varying durations of between 24 to 120 hours, in 1M HCl medium containing a varying concentrations of the leaves extract (0.25g/L, - 1.25g/L). The results show that corrosion rates dropped from a value of 0.49 mgcm-2hr-1 for the uninhibited medium to a value of 0.15 mgcm-2hr-1 for the inhibited medium of 1M HCl in 0.25 g/l of the extract. Values of corrosion inhibition efficiencies of 70.38-85.11% were observed as the concentration of the inhibitor were increased from 0.25g/L, - 1.25g/L. Corrosion Inhibition was found to increase with increase in immersion time and temperature. The magnitude of the Ea indicates that the interaction between the metal surface and the inhibitor was chemisorptions. The Adsorption process fit into the Langmuir isotherm model with a correlation coefficient of 0.97. Evidence from molecular dynamics model shows that Methyl stearate (Line 5) and (3Z, 13Z)-2-methyloctadeca-3,13-dien-1-ol (line 11) were found to have the highest binding energy of -197.69 ± 3.12 and-194.56 ± 10.04 in kcal/mol respectively. The binding energy of these compounds indicates that they would be a very good corrosion inhibitor for mild steel and other Fe related materials.

Keywords: binding energy, corrosion, inhibitor, Langmuir isotherm, mild steel.

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Authors: Nicole Bandow, Peter Emmermacher, Oliver Wienert, Steffen Masik, Kerstin Witte

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Karate-kumite is a fast sport where a good perception and anticipation of movements is needed in order to respond appropriately. Perception and anticipation are therefore essential for an efficient and precise movement control and a limiting factor in karate kumite. Previous studies only used 2D video technologies combined with the occlusion technique to study anticipation in sports. These studies showed limitations in the usage of 2D video footage in regards to realism and the presentation of depth information. To overcome these issues a virtual 3D environment was developed to create a similar to real life environment. The aim of this study was to compare the differences in responses of intermediate and expert karate athletes towards temporally and spatially occluded virtual karate attacks from two attackers. Five male expert and five intermediate karate athletes responded physically to nine (3 temporal combined with 3 spatial) occluded attacks of the Gyaku-Zuki of each attacker in the 3D virtual environment. The responses were evaluated in regards to correct point of time and appropriate response technique. Significant differences between the expertises’ responses for the attackers were found. Experts respond more often correct to early information of attacks than novices.

Keywords: anticipation, karate, occlusion, virtual reality

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Authors: M. R. Daneshgar, S. E. Habibi, E. Daneshgar, A. Daneshgar

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In this paper, a two-dimensional method is developed to simulate the fillet welds in a stiffened cylindrical shell, using finite element method. The stiffener material is aluminum 2519. The thermo-elasto-plastic analysis is used to analyze the thermo-mechanical behavior. Due to the high heat flux rate of the welding process, two uncouple thermal and mechanical analysis are carried out instead of performing a single couple thermo-mechanical simulation. In order to investigate the effects of the welding procedures, two different welding techniques are examined. The resulted residual stresses and distortions due to different welding procedures are obtained. Furthermore, this study employed the technique of element birth and death to simulate the weld filler variation with time in fillet welds. The obtained results are in good agreement with the published experimental and three-dimensional numerical simulation results. Therefore, the proposed 2D modeling technique can effectively give the corresponding results of 3D models. Furthermore, by inspection of the obtained residual hoop and transverse stresses and angular distortions, proper welding procedure is suggested.

Keywords: stiffened cylindrical shell, fillet welds, residual stress, angular distortion, finite element method

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Authors: A. G. Akhundov

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Issues of obtaining unbiased data on the status of pipeline systems of oil- and oil product transportation become especially important when laying and operating pipelines under severe nature and climatic conditions. The essential attention is paid here to researching exogenous processes and their impact on linear facilities of the pipeline system. Reliable operation of pipelines under severe nature and climatic conditions, timely planning and implementation of compensating measures are only possible if operation conditions of pipeline systems are regularly monitored, and changes of permafrost soil and hydrological operation conditions are accounted for. One of the main reasons for emergency situations to appear is the geodynamic factor. Emergency situations are proved by the experience to occur within areas characterized by certain conditions of the environment and to develop according to similar scenarios depending on active processes. The analysis of natural and technical systems of main pipelines at different stages of monitoring gives a possibility of making a forecast of the change dynamics. The integration of GIS technologies, traditional means of geotechnical monitoring (in-line inspection, geodetic methods, field observations), and remote methods (aero-visual inspection, aero photo shooting, air and ground laser scanning) provides the most efficient solution of the problem. The united environment of geo information system (GIS) is a comfortable way to implement the monitoring system on the main pipelines since it provides means to describe a complex natural and technical system and every element thereof with any set of parameters. Such GIS enables a comfortable simulation of main pipelines (both in 2D and 3D), the analysis of situations and selection of recommendations to prevent negative natural or man-made processes and to mitigate their consequences. The specifics of such systems include: a multi-dimensions simulation of facilities in the pipeline system, math modelling of the processes to be observed, and the use of efficient numeric algorithms and software packets for forecasting and analyzing. We see one of the most interesting possibilities of using the monitoring results as generating of up-to-date 3D models of a facility and the surrounding area on the basis of aero laser scanning, data of aerophotoshooting, and data of in-line inspection and instrument measurements. The resulting 3D model shall be the basis of the information system providing means to store and process data of geotechnical observations with references to the facilities of the main pipeline; to plan compensating measures, and to control their implementation. The use of GISs for geotechnical monitoring of pipeline systems is aimed at improving the reliability of their operation, reducing the probability of negative events (accidents and disasters), and at mitigation of consequences thereof if they still are to occur.

Keywords: databases, 3D GIS, geotechnical monitoring, pipelines, laser scaning

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Authors: Salim Al Jadidi, Shian Gao, Shivananda Moolya

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Computational Fluid Dynamic (CFD) technique coupled with Sub-Grid-Scale (SGS) model is used to study the flow behavior of heavy oil-water-air flow in a horizontal pipe by adapting ANSYS Fluent CFD software. The technique suitable for the transport of water-lubricated heavy viscous oil in a horizontal pipe is the Core Annular flow (CAF) technique. The present study focuses on the numerical study of CAF adapting Large Eddy Simulations (LES). The basic objective of the present study is to gain a basic knowledge of the flow behavior of heavy oil using turbulent CAF through a conventional horizontal pipe. This work also focuses on the success and applicability of LES. The simulation of heavy oil-water-air three-phase flow and two-phase flow of heavy oil–water in a conventional horizontal pipe is performed using ANSYS Fluent 16.2 software. The influence of three-phase heavy oil-water air flow in a selected pipe is affected by gravity. It is also observed from the result that the air phase and the variation in the temperature impact the behavior of the annular stream and pressure drop. Some results obtained during the study are validated with the results gained from part of the literature experiments and simulations, and the results show reasonably good agreement between the studies.

Keywords: computational fluid dynamics, gravity, heavy viscous oil, three-phase flow

Procedia PDF Downloads 79

Authors: Piyarat Parklug, Busaba Supawattanaobodee, Penpat Pinyowattanasilp

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The radioactive iodine thyroid uptake (RAIU) has been widely used to differentiate the cause of thyrotoxicosis and treatment. Twenty-four hours RAIU is routinely used to calculate the dose of radioactive iodine (RAI) therapy; however, 2 days protocol is required. This study aims to evaluate the modification of Penpat Pinyowattanasilp equation application by the exclusion of outlier data, 3 hours RAIU less than 20% and more than 80%, to improve prediction of 24-hour uptake. The equation is predicted 24 hours RAIU (P24RAIU) = 32.5+0.702 (3 hours RAIU). Then calculating separation first and second therapeutic doses in Graves’ disease patients. Methods; This study was a retrospective study at Faculty of Medicine Vajira Hospital in Bangkok, Thailand. Inclusion were Graves’ disease patients who visited RAI clinic between January 2014-March 2019. We divided subjects into 2 groups according to first and second therapeutic doses. Results; Our study had a total of 151 patients. The study was done in 115 patients with first RAI dose and 36 patients with second RAI dose. The P24RAIU are highly correlated with actual 24-hour RAIU in first and second therapeutic doses (r = 0.913, 95% CI = 0.876 to 0.939 and r = 0.806, 95% CI = 0.649 to 0.897). Bland-Altman plot shows that mean differences between predictive and actual 24 hours RAI in the first dose and second dose were 2.14% (95%CI 0.83-3.46) and 1.37% (95%CI -1.41-4.14). The mean first actual and predictive therapeutic doses are 8.33 ± 4.93 and 7.38 ± 3.43 milliCuries (mCi) respectively. The mean second actual and predictive therapeutic doses are 6.51 ± 3.96 and 6.01 ± 3.11 mCi respectively. The predictive therapeutic doses are highly correlated with the actual dose in first and second therapeutic doses (r = 0.907, 95% CI = 0.868 to 0.935 and r = 0.953, 95% CI = 0.909 to 0.976). Bland-Altman plot shows that mean difference between predictive and actual P24RAIU in the first dose and second dose were less than 1 mCi (-0.94 and -0.5 mCi). This modification equation application is simply used in clinical practice especially patient with 3 hours RAIU in range of 20-80% in a Thai population. Before use, this equation for other population should be tested for the correlation.

Keywords: equation, Graves’disease, prediction, 24-hour uptake

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Authors: Ahmed A. Abd El Rahim, Andrew Anis Fakhrey Mosaad

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Background: An important psychological issue that has an impact on both mental and physical function is anxiety disorders. The general consensus is that aerobic exercise and physical activity are good for lowering anxiety and mood. Purpose: This study's goal was to look into how patients with anxiety disorders responded to aerobic exercise. Subjects: Anxiety disorders were identified in 30 individuals from the psychiatric hospital at Sohag University who were chosen based on inclusive criteria and had ages ranging from 25 to 45. Methods: Patients were split into two equal groups at random: For four weeks, three sessions per week, fifteen patients in group A (the study group), seven men and eight women, underwent medication therapy and aerobic exercise. Age (28.4 ± 2.11 years), weight (72.5 ± 10.06 kg), height (164.8 ± 9.64 cm), and BMI (26.65 ± 2.68 kg/m2) were all mean SD values. And in Group B (Control Group), only medication therapy was administered to 15 patients (9 males and 6 females). Age (29.6 ± 3.68), weight (75 ± 7.07 kg), height (166.9 ± 6.75) cm, and BMI (26.87 ± 1.11) kg/m2 were the mean SD values. Before and after the treatment, the Hamilton Anxiety Scale was used to gauge the patient's degree of anxiety. Results: Within the two groups, there were significant differences both before and after the treatment. Following therapy, there was a significant difference between the two groups; the study group displayed better improvement on the Hamilton Anxiety Scale. Conclusion: Patients with anxiety problems can benefit from aerobic activities and antianxiety drugs as effective treatments for lowering anxiety levels.

Keywords: aerobic exercises, anxiety disorders, antianxiety medications, Hamilton anxiety scale

Procedia PDF Downloads 85

Authors: Bhavesh Dadhich, Fenil Bamnoliya, Akshita Swaminathan

Abstract:

This project aims to design a system to generate energy from flowing wind due to the motion of a vehicle on the road or from the flow of wind in compact areas to utilize the wasteful energy into a useful one. It is envisaged through a design and aerodynamic performance improvement of a Savonius vertical axis wind turbine rotor and used in an integrated system with a Triboelectric Nanogenerator (TENG) that can generate a good amount of electrical energy. Aerodynamic calculations are performed numerically using Computational Fluid Dynamics software, and TENG's performance is evaluated analytically. The Turbine's coefficient of power is validated with published results for an inlet velocity of 7 m/s with a Tip Speed Ratio of 0.75 and found to reasonably agree with that of experiment results. The baseline design is modified with a new blade arc angle and rotor position angle based on the recommended parameter ranges suggested by previous researchers. Simulations have been performed for different T.S.R. values ranging from 0.25 to 1.5 with an interval of 0.25 with two applicable free stream velocities of 5 m/s and 7m/s. Finally, the newly designed VAWT CFD performance results are used as input for the analytical performance prediction of the triboelectric nanogenerator. The results show that this approach could be feasible and useful for small power source applications.

Keywords: savonius turbine, power, overlap ratio, tip speed ratio, TENG

Procedia PDF Downloads 124

Authors: A. G. Margaryan

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Ability of adaptation of the organism is considered as an important component of health in maintaining relative dynamic constancy of the hemostasis and functioning of all organs and systems. Among the various forms of adaptation (individual, species and mental), social adaptation of the organism has a particular role. The aim of this study was to evaluate the subjective perception of social factors, social welfare and the level of adaptability of Armenian physicians. The survey involved 2,167 physicians (592 men and 1,575 women). According to the survey, most physicians (75.1%) were married. It was found that 88.6% of respondents had harmonious family relationships, 7.6% of respondents – tense relationships, and 1.0% – marginal relationships. The results showed that the average monthly salary with all premium payments amounted to 88 263.6±5.0 drams, and 16.7% of physicians heavily relied on the material support of parents or other relatives. Low material welfare was also confirmed by the analysis of the living conditions. Analysis of the results showed that the degree of subjective perception of social factors of different specialties averaged 11.3±3.1 points, which corresponds to satisfactory results (a very good result – 4.0 points). The degree of social adaptation of physicians on average makes 4.13±1.9 points, which corresponds to poor results (allowable less than 3.0 points). The distribution of the results of social adaptation severity revealed that the majority of physicians (58.6%) showed low social adaptation, average social adaptation is observed in 22.4% of the physicians and high adaptation – in only 17.4% of physicians. In conclusions, the findings of this study suggest that the degree of social adaptation of currently practicing physicians is low.

Keywords: physician's health, social adaptation, social factor, social health

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Authors: M. N. A. Abdullah, Pritha Roy, R. R. Shil, D. R. Sarker

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Alpha-nucleus interaction is obscured because it produces enhanced cross-sections at large scattering angles known as anomaly in large angle scattering (ALAS). ALAS is prominent in the elastic scattering of α-particles as well as in non-elastic processes involving α-particles for incident energies up to 50 MeV and for targets of mass A ≤ 50. The Woods-Saxon type of optical model potential fails to describe the processes in a consistent manner. Folded potential is a good candidate and often used to construct the potential which is derived from the microscopic as well as semi-microscopic folding calculations. The present work reports the analyses of the elastic scattering of α-particles from ²⁴Mg and ²⁸Si at Eα=22-100 MeV and 14.4-120 MeV incident energies respectively in terms of the modified single-folded (MSF) potential. To derive the MSF potential, we take the view that the nucleons in the target nuclei ²⁴Mg and ²⁸Si are primarily in α-like clusters and the rest of the time in unclustered nucleonic configuration. The MSF potential, found in this study, does not need any renormalization over the whole range of incident α energies, and the renormalization factor has been found to be exactly 1 for both the targets. The best-fit parameters yield 4Aα = 21 and AN = 3 for α-²⁴Mg potential, and 4Aα = 26 and AN = 2 for α-²⁸Si potential in time-average pictures. The root-mean-square radii of both ²⁴Mg and ²⁸Si are also deduced, and the results obtained from this work agree well with the outcomes of other studies.

Keywords: elastic scattering, optical model, folded potential, renormalization

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Authors: Pechpailin Kortnoi, Tanitnun Paprad

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Background: Myasthenia gravis (MG) is an autoimmune disorder characterized by impaired neuromuscular transmission due to antibodies against nicotinic receptors, leading to muscle weakness, ptosis, and respiratory issues. The incidence of MG has risen globally, emphasizing the need for effective diagnostics. Objective: This study evaluates the validity of a combined bedside test (the ice pack test and fatigability test) for diagnosing juvenile myasthenia gravis (JMG) in pediatric patients with ptosis. Methods: This cross-sectional study, conducted from January 2012 to May 2024 at King Chulalongkorn Memorial Hospital, Thailand, included pediatric patients (1 month to 18 years) with ptosis undergoing ice pack and fatigability tests. Data included demographics, clinical findings, and test results. Diagnostic efficacy was assessed using sensitivity, specificity, accuracy, PPV, NPV, Fagan Nomogram, Kappa Statistics, and McNemar’s Chi-Square. Results: Of 43 identified patients, 32 were included, with 47% male and a mean age of 7 years. The combined bedside test had high sensitivity (92.8%) and accuracy (87.5%) but moderate specificity (50%). It significantly outperformed the ice pack test (P = 0.0005), which showed low sensitivity (42.8%) and accuracy (43.8%). The fatigability test had 82% sensitivity and 92% PPV. Confirmatory tests (AChR-Ab, MuSK-Ab, neostigmine, repetitive nerve stimulation) supported most diagnoses. Conclusions: The combined bedside test, with high sensitivity (92.8%) and accuracy (87.5%), is an effective screening tool for juvenile myasthenia gravis, outperforming the ice pack test. Integrating it into clinical practice may improve diagnosis and enable timely treatment. The fatigability test (82% sensitivity) is also useful as an adjunct screening tool.

Keywords: myasthenia gravis, the fatigability test, the ice pack test, the combined bedside test

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Authors: Abdul Basit, Amil Daraz, Guoqiang Zhang

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With the increasing demand for wireless communication systems for unlicensed indoor applications, the FCC, in February 2002, allocated unlicensed bands ranging from 3.1 GHZ to 10.6 GHz with fractional bandwidth of about 109 %, because it plays a key role in the radiofrequency (RF) front ends devices and has been widely applied in many other microwave circuits. Targeting the proposed band defined by the FCC for the UWB system, this article presents a UWB bandpass filter with three stop bands for the mitigation of wireless bands that may interfere with the UWB range. For this purpose, two resonators are utilized for the implementation of triple-notched bands. The C-shaped resonator is used for the first notch band creation at 3.4 GHz to suppress the WiMAX signal, while the H-shaped resonator is employed in the initial UWB design to introduce the dual notched characteristic at 4.5 GHz and 8.1 GHz to reject the WLAN and Satellite Communication signals. The overall circuit area covered by the proposed design is 30.6 mm × 20 mm, or in terms of guided wavelength at the first stopband, its size is 0.06 λg × 0.02 λg. The presented structure shows a good return loss under -10 dB over most of the passband and greater than -15 dB for the notched frequency bands. Finally, the filter is simulated and analyzed in HFSS 15.0. All the bands for the rejection of wireless signals are independently controlled, which makes this work superior to the rest of the UWB filters presented in the literature.

Keywords: a bandpass filter (BPF), ultra-wideband (UWB), wireless communication, C-shaped resonator, triple notch

Procedia PDF Downloads 84