Search results for: human structure interaction

Authors: Nina Robson, Kenneth John Faller II, Vishalkumar Ahir, Mustafa Mhawesh, Reza Langari

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This paper describes the development of a model of an impaired human arm performing a reaching motion, which will be used to predict hand path trajectories for people with reduced arm joint mobility. Assuming that the arm was in contact with a surface during the entire movement, the contact conditions at the initial and final task locations were determined and used to generate the entire trajectory. The model was validated by comparing it to experimental data, which simulated an arm joint impairment by physically constraining the joint motion with a brace. Future research will include using the model in the development of physical training protocols that avoid early recruitment of “healthy” Degrees-Of-Freedom (DOF) for reaching motions, thus facilitating an Active Range-Of-Motion Recovery (AROM) for a particular impaired joint.

Keywords: higher order kinematic specifications, human motor coordination, impaired movement, kinematic synthesis

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Authors: Mehravar Javid, James Sexton, Farzaneh Amani, Kainaz Patravala

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Self-expansion is a procedure through which people expand the dimensions of their self-concept by incorporating novel content into their sense and experience of identity. Greater self-expansion predicts positive consequences for individuals and romantic relationships. The self-expansion questionnaire (SEQ) originally developed by Lewandowski & Aron (2002) assumes that self-expansion is constituted of key components from the self-expansion model. This study aimed to confirm the factor structure of SEQ and adapt the questions of the scale to the Iranian culture. The sample included 190 participants who responded to 14 items and were selected by simple random sampling. Using Amos-21 and SPSS-21, descriptive statistics, Pearson correlation and Confirmatory Factor Analysis (CFA) were calculated. Cronbach’s alpha coefficient for total SEQ items was 0.92. Results of CFA supported the factor structure SEQ [RMSEA=0.08, GFI=0.88 and CFI=0.92] that showed the model has a good fit and also all the items of SEQ, have a high correlation and have a direct and significant relationship. So, the SEQ demonstrated acceptable psychometric properties in Tehran University students. Looking forward, it would be interesting and exciting to see the implications of the scale as applied to romantic relationships.

Keywords: validity, reliability, confirmatory factor analysis, self-expansion questionnaire

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Authors: Pintip Vajarothai, Saad Al-Jibouri, Johannes I. M. Halman

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Public investment projects are primarily aimed at achieving development strategies to increase national economies of scale and overall improvement in a country. However, experience shows that public projects, particularly in developing countries, struggle or fail to fulfill the immediate needs of local communities. In many cases, the reason for that is that projects are selected in a subjective manner and that a major part of the problem is related to the evaluation criteria and techniques used. The evaluation process is often based on a broad strategic economic effects rather than real benefits of projects to society or on the various needs from different levels (e.g. national, regional, local) and conditions (e.g. long-term and short-term requirements). In this paper, an extensive literature review of the types of criteria used in the past by various researchers in project evaluation and selection process is carried out and the effectiveness of such criteria and techniques is discussed. The paper proposes substitute social and project sustainability criteria to improve the conditions of local people and in particular the disadvantaged groups of the communities. Furthermore, it puts forward a way for modelling the interaction between the selected criteria and the achievement of the social goals of the affected community groups. The described work is part of developing a broader decision model for public investment project selection by integrating various aspects and techniques into a practical methodology. The paper uses Thailand as a case to review what and how the various evaluation techniques are currently used and how to improve the project evaluation and selection process related to social and sustainability issues in the country. The paper also uses an example to demonstrates how to test the feasibility of various criteria and how to model the interaction between projects and communities. The proposed model could be applied to other developing and developed countries in the project evaluation and selection process to improve its effectiveness in the long run.

Keywords: evaluation criteria, developing countries, public investment, project selection methodology

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Authors: Aline M. C. Santoro, João C. Pantoja, Eduardo P. Rossetti

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While the aim of the modernist movement was to deny known typology, the creation of a new formal language also gave it new meaning, which was now related to Form. This is specifically true in the modern capital of Brazil, where Niemeyer sought to demonstrate the manner in which the new materials available, such as reinforced concrete, were able to produce innovative forms. With this study, we aim to demonstrate the relationship between Niemeyer’s forms and the topological typology known as tessellation, through the presentation of two case studies, the Monument to Caxias and the Saint George Orthodox Church. At a first glance, our purpose is to present the definition of Form, especially with relationship to the works of Niemeyer, seeking to identify in them the concepts presented by Moussavi. Afterwards, we will use a computer-based approach to study and model the forms of two of his buildings with the McNeel Rhinoceros program, where, with the aid of diagrams and renderings, we will be able to clearly and legibly represent their organic forms and further understand their structural systems. When we recognise the concept of typology as a starting point for structural form, it can be concluded that the case studies presented here are encompassed by the typology presented by Moussavi since they derive from his basic structural systems.

Keywords: form, Niemeyer, structure, typology, topology

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Authors: Jhen-Ting Huang, Chia-Chia Chang, Hu-Cheng Weng, An-Ya Lo

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In this study, Co3O4-CNT-Graphene composite electrode was deposited by electrophoretic deposition (EPD) method, where micro polystyrene spheres (PSs) were added for co-deposition. Applied with heat treatment, a hierarchical porosity is left in the electrode which is beneficial for supercapacitor application. In terms of charge and discharge performance, we discussed the optimal CNT/Graphene ratio, macroporous ratio, and the effect of Co3O4 addition on electrode capacitance. For materials characterization, scanning electron microscope (SEM), X-ray diffraction, and BET were applied, while cyclic voltammetry (CV) and chronopotentiometry (CP) measurements, and Ragone plot were applied as in-situ analyses. Based on this, the effects of PS amount on the structure, porosity and their effect on capacitance of the electrodes were investigated. Finally, the full device performance was examined with charge-discharge and electron impedance spectrum (EIS) methods. The results show that the EPD coating with hierarchical porosity was successfully demonstrated in this study. As a result, the capacitance was greatly enhanced by 2.6 times with the hierarchical structure.

Keywords: supercapacitor, nanocarbon tub, graphene, metal oxide

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Authors: Ann Ying-An Chen, Yi-Lun Tsai, Hso-Chi Chaung

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An understanding of pathogens and the immune system has played an utmost important role in agricultural research for the development of vaccinations. The immunological synapse, cell to cell interaction play a crucial role in triggering the body's immune system, such as activation between antigen-presenting cells (APCs) and different subsets of T-cell. If these interactions are regulated appropriately, the host has the ability to defend itself against a wide spectrum of infectious pathogens. The aim of this study is to establish and to characterize a porcine immune synapse system by co-culturing T cell/APC. In this study, blood samples were collected from specific-pathogen-free piglets, and peripheral blood mononuclear cells (PBMC) were separated by using Ficoll-Pague. The PBMC were then stained with CD4 (FITC) and CD25 (PE) antibodies. Different subsets of T cells sorted by fluorescence-activated cell sorting flow cytometer were co-cultured for 24 hrs with alveolar macrophages, and the profiles of cytokine secretion and mRNA transcription levels of Toll-like receptors were examined after. Results showed that the three stages of immune synapse were clearly visible and identified under both transmission and scanning electron microscope (TEM and SEM). The significant interaction differences in toll-like receptor expressions within the co-cultured cell system were observed. The TLR7 mRNA expressions in CD4+CD25- cells were lower than those in CD4+CD25+ and CD4 -CD25+. Interestingly, the IL-10 production levels in CD4+CD25- cells (7.732 pg/mL) were significantly higher than those of CD4+CD25+ (2.636 pg/mL) and CD4 -CD25+ (2.48 pg/mL). These findings demonstrated that a clear understanding of the porcine immune synapse system can contribute greatly for further investigations on the mechanism of T-cell activation, which can benefit in the discovery of potential adjuvant candidate or effective antigen epitopes in the development of vaccinations with high efficacy.

Keywords: antigen-presenting cells, immune synapse, pig, T subsets, toll-like receptor

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Authors: A. Gulbiniene, V. Jankauskaite

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Textile laminates with breathable membranes are used extensively in protective footwear. Such polymeric membranes act as a barrier to liquid water and soil entry from the environment, but are sufficiently permeable to water vapour to allow significant amounts of sweat to evaporate and affect the comfort of the wearer. In this paper the influence of absorbed humidity amount on the electrical properties of textiles lining laminates with and without polymeric membrane is presented. It was shown that textile laminate structure and its layers have a great influence on the water vapour absorption. Laminates with polyurethane foam layers show lower ability to absorb water vapour. Semi-permeable membrane increases absorbed humidity amount. The increase of water vapour absorption ability decreases textile laminates' electrical resistance. However, the intensity of the decrease in electrical resistance depends on the textile laminate layers' nature. Laminates with polyamide layers show significantly lower electrical resistance values.

Keywords: electrical resistance, humid atmosphere, textiles laminate, water vapour absorption

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Authors: Edwina Owusu Panin, Kwame Baah Owusu Panin

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This abstract intends to demonstrate multiple strategies of autism management in Ghana by exploring the possibilities. The advantages of adopting creative art forms as a therapeutic method. Autism is a developmental disorder that includes social interaction, communication, and repetitive behaviours. In Ghana, as in many other countries, there is a rising demand for effective intervention and support for people with autism and their families. Creative arts such as music, dance, drama and visual arts have shown promise in promoting communication, social interaction and inclusion of people with autism. These art forms provide alternative channels for self-expression and can be powerful tools for autistic people to interact with the world, their friends and families around them. Creative art forms interventions have been found to improve social skills, improve emotion regulation, promote creativity and increase self-confidence in people with autism. This study examines existing programs and interventions in Ghana involving creative art forms for people with autism through a comparative analysis. It explores the different approaches, methods and results of these interventions. By comparing and evaluating these programs, the study aims to identify best practices, challenges and areas for development in managing autism through the creative arts in Ghana. Although many schools and rehabilitation centres employ various forms in therapeutic approaches for autism. There is no comparative analysis of which type of autism and which creative art forms is suitable. The results of this study will contribute to the development of evidence-based practices for the management of autism in Ghana. It provides valuable information about the effectiveness of creative arts interventions and helps inform policy makers, educators, therapists and other stakeholders involved in autism support. Ultimately, the goal is to improve the well-being and quality of life of people with autism in Ghana and their families by promoting inclusive and accessible interventions that harness the power of creative art forms.

Keywords: autism, therapeutic, creative art, art form

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Authors: Ali Mohaghar, Iman Ghasemian Sahebi, Alireza Arab

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In the last decades, increasing in human and natural disaster occurrence had very irreparable effects on human life. Hence, one of the important issues in humanitarian supply chain management is identifying and prioritizing the different risks and finding suitable solutions for encountering them at the time of disaster occurrence. This study is an attempt to provide a comprehensive review of humanitarian supply chain risks in a case study of Tehran Red Crescent Societies. For this purpose, Best-Worst method (BWM) has been used for analyzing the risks of the humanitarian supply chain. 22 risks of the humanitarian supply chain were identified based on the literature and interviews with four experts. According to BWM method, the importance of each risk was calculated. The findings showed that culture contexts, little awareness of people, and poor education system are the most important humanitarian supply chain risks. This research provides a useful guideline for managers so that they can benefit from the results to prioritize their solutions.

Keywords: Best-Worst Method, humanitarian logistics, humanitarian supply chain, risk management

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Authors: Cigdem Fidan

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Deaf students in Turkey generally do not have access to foreign language classes. However, the knowledge of foreign languages, especially English, is important for them to access knowledge and other opportunities in the globalizing world. In addition, learning any language including foreign languages is a basic linguistic human right. This study applies critical discourse analysis to examine language ideologies, perceptions of deafness and current language and education policies used for deaf education in Turkey. The findings show that representation of deafness as a disability in policy documents, ignorance the role of sign languages in education and lack of policies that support foreign language education for the deaf may result in inaccessibility of foreign language education for deaf students in Turkey. The paper concludes with recommendations for policymakers, practitioners, and advocates for the deaf.

Keywords: deaf learners, English as a foreign language, language policy, linguistic human rights

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Authors: Chul Lee, Seoae Cho, Erich D. Jarvis, Heebal Kim

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Vocal learning, the ability to imitate vocalizations based on auditory experience, is a homoplastic character state observed in different independent lineages of animals such as songbirds, parrots, hummingbirds and human. It has now become possible to perform genome-wide molecular analyses across vocal learners and vocal non-learners with the recent expansion of avian genome data. It was analyzed the whole genomes of human and 48 avian species including those belonging to the three avian vocal learning lineages, to determine if behavior and neural convergence are associated with molecular convergence in divergent species of vocal learners. Analyses of 8295 orthologous genes across bird species revealed 141 genes with amino acid substitutions specific to vocal learners. Out of these, 25 genes have vocal learner specific genetic homoplasies, and their functions were enriched for learning. Several sites in these genes are estimated under convergent evolution and positive selection. A potential role for a subset of these genes in vocal learning was supported by associations with gene expression profiles in vocal learning brain regions of songbirds and human disease that cause language dysfunctions. The key candidate gene with multiple independent lines of the evidences specific to vocal learners was DRD5. Our findings suggest cAMP-based learning pathway in avian vocal learners, indicating molecular homoplastic changes associated with a complex behavioral trait, vocal learning.

Keywords: amino acid substitutions, convergent evolution, positive selection, vocal learning

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Authors: Itsuo Yokoyama, Rikako Kikuti, Miti Sekikawa, Tosinori Asai, Sarai Tsuyoshi

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Introduction: Vascular access for hemodialysis therapy is often difficult, even for experienced medical personnel. Ultrasound guided needle placement have been performed occasionally but is not always helpful in certain cases with complicated vascular anatomy. Obtaining precise anatomical knowledge of the vascular structure is important to prevent access-related complications. With augmented reality (AR) device such as AR glasses, the virtual vascular structure is shown superimposed on the actual patient vessels, thus enabling the operator to maneuver catheter placement easily with free both hands. We herein report our method of AR guided vascular access method in dialysis treatment Methods: Three dimensional (3D) object of the arm with arteriovenous fistula is computer graphically created with 3D software from the data obtained by computer tomography, ultrasound echogram, and image scanner. The 3D vascular object thus created is viewed on the screen of the AR digital display device (such as AR glass or iPad). The picture of the vascular anatomical structure becomes visible, which is superimposed over the real patient’s arm, thereby the needle insertion be performed under the guidance of AR visualization with ease. By this method, technical difficulty in catheter placement for dialysis can be lessened and performed safely. Considerations: Virtual reality technology has been applied in various fields and medical use is not an exception. Yet AR devices have not been widely used among medical professions. Visualization of the virtual vascular object can be achieved by creation of accurate three dimensional object with the help of computer graphical technique. Although our experience is limited, this method is applicable with relative easiness and our accumulating evidence has suggested that our method of vascular access with the use of AR can be promising.

Keywords: abdominal-aorta, calcification, extraskeletal, dialysis, computer graphics, 3DCG, CT, calcium, phosphorus

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Authors: Dechao Meng, Yongqi Dong, Qiyuan Feng, Zhangzhang Cui, Xiang Hu, Haoliang Huang, Genhao Liang, Huanhua Wang, Hua Zhou, Hawoong Hong, Jinghua Guo, Qingyou Lu, Xiaofang Zhai, Yalin Lu

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Great efforts have been taken to reveal the intrinsic origins of emerging ferromagnetism (FM) in strained LaCoO₃ (LCO) films. However, some macro magnetic performances of LCO are still not well understood and even controversial, such as magnetic anisotropy. Determining and understanding magnetic anisotropy might help to find the true causes of FM in turn. Perpendicular magnetic anisotropy (PMA) was the first time to be directly observed in high-quality LCO films with different thickness. The in-plane (IP) and out of plane (OOP) remnant magnetic moment ratio of 30 unit cell (u.c.) films is as large as 20. The easy axis lays in the OOP direction with an IP/OOP coercive field ratio of 10. What's more, the PMA could be simply tuned by changing the thickness. With the thickness increases, the IP/OOP magnetic moment ratio remarkably decrease with magnetic easy axis changing from OOP to IP. Such a huge and tunable PMA performance exhibit strong potentials in fundamental researches or applications. What causes PMA is the first concern. More OOP orbitals occupation may be one of the micro reasons of PMA. A cluster-like magnetic domain pattern was found in 30 u.c. with no obvious color contrasts, similar to that of LaAlO₃/SrTiO₃ films. And the nanosize domains could not be totally switched even at a large OOP magnetic field of 23 T. It indicates strong IP characters or none OOP magnetism of some clusters. The IP magnetic domains might influence the magnetic performance and help to form PMA. Meanwhile some possible nonmagnetic clusters might be the reason why the measured moments of LCO films are smaller than the calculated values 2 μB/Co, one of the biggest confusions in LCO films.What tunes PMA seems much more interesting. Totally different magnetic domain patterns were found in 180 u.c. films with cluster magnetic domains surrounded by < 110 > cross-hatch lines. These lines were regarded as structure domain walls (DWs) determined by 3D reciprocal space mapping (RSM). Two groups of in-plane features with fourfold symmetry were observed near the film diffraction peaks in (002) 3D-RSM. One is along < 110 > directions with a larger intensity, which is well match the lines on the surfaces. The other is much weaker and along < 100 > directions, which is from the normal lattice titling of films deposited on cubic substrates. The < 110 > domain features obtained from (103) and (113) 3D-RSMs exhibit similar evolution of the DWs percentages and magnetic behavior. Structure domains and domain walls are believed to tune PMA performances by transform more IP magnetic moments to OOP. Last but not the least, thick films with lots of structure domains exhibit different electrical transport behaviors. A metal-to-insulator transition (MIT) and an angular dependent negative magnetic resistivity were observed near 150 K, higher than FM transition temperature but similar to that of spin-orbital coupling related 1/4 order diffraction peaks.

Keywords: structure domain, magnetic anisotropy, magnetic domain, domain wall, 3D-RSM, strain

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Authors: Inyene Nathaniel Nkanta

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The present economic situation in Nigeria, with an increase in inflation rate due to the fall of crude oil prices and post covid-19 crisis, has increased the level of poverty and suffering in Nigeria, particularly the women. Against that backdrop, this research project is initiated to explore ways to empower women through entrepreneurship education and training to ameliorate the poverty level amongst women in Nigeria. A qualitative approach to data collection will be applied in this study and to test the assertions of this research project empirically, this research adopts a case study research method as this will enable me to obtain and probe ways women can be empowered through semi-structured interviews and focus groups. The result of this research project will provide an original perspective on human capital development, most importantly, the need for entrepreneurial education and entrepreneurial literature and practice.

Keywords: women, Nigeria, entrepreneurship education, Economic development, human capital

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Authors: Mohammad Parvaresh, Mahdi Babaee, Bahareh Arghand, Davood Nourmohammadi

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Environmental degradation is caused by social inequalities and the inappropriate use of nature and a factor in the violation of human rights. Indeed, the right to a safe, healthy and ecologically-balanced environment is an independent human right. Therefore, the relationship between human rights and environmental protection is crucial for the study of social justice and sustainable development, and environmental problems are a result of the failure to realize social and economic justice. In this regard, 'article 50 of the constitution of the Islamic Republic of Iran as a general principle have many of the concepts of sustainable development, including: the growth and improvement of human life, the rights of present and future generations, and the integrity of the inner and outer generation, the prohibition of any environmental degradation'. Also, Charter on Citizen’s Rights, which was conveyed by the President of the Islamic Republic of Iran, Mr. Rouhani refers to the right to a healthy environment and sustainable development. In this regard in 2013, Tehran Province Water and Wastewater Co. defined a plan called 'Tehran’s Health Line' was includes Western and Eastern part by about 26 kilometers of water transferring pipelines varied 1000 to 2000 mm diameters. This project aims to: (1) Transfer water from the northwest water treatment plant to the southwest areas, which suffer from qualitative and quantitative water, in order to mix with the improper wells’ water; (2) Reducing the water consumption provided by harvesting from wells which results in improving the underground water resources, causing the large settlements and stopping the immigrating slums into the center or north side of the city. All of the financial resources accounted for 53,000,000 US$ which is mobilized by Tehran Province Water and Wastewater Co. to expedite the work. The present study examines the Tehran Health Line plan and the purpose of implementation of this plan to achieve environmental protection, environmental justice and citizenship rights for all people who live in Tehran.

Keywords: environmental justice, international environmental law, erga omnes, charter on citizen's rights, Tehran health line

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Authors: Adnan I. O. Zaid

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Zinc aluminum alloys are versatile materials which are widely used in manufacturing several parts in the automobile and aircraft industries. The effect of grain refinement of these alloys by rare earth elements on their mechanical characteristics is scarce. The equal channel angular pressing is relatively recent method for producing severe plastic deformation in materials subjected to it resulting in refinement of their structure and enhancement of their mechanical characteristics. The phase diagram of these alloys indicates that large dendrites of large grain size can be formed during their solidification of the cast which tends to deteriorate their mechanical strength and surface quality. To overcome this problem they are normally grain refined by either titanium or titanium + boron to their melt prior to solidification. In this paper, comparison between the effect of adding either titanium, (Ti), titanium+boron, (Ti+B), or Molybdenum, Mo, to zinc-aluminum22, alloy, (ZA22) on its metallurgical and mechanical characteristics in the cast condition and after pressing by the ECAP process is investigated. It was found that addition of either Ti, Ti+B, or Mo to the ZA22 alloy in the cast condition resulted in refining of their structure being more refined by the addition of Mo, then .Ti+B and less refining by Ti addition. Furthermore, the ECAP process resulted in further refinement of the alloy micro structure except in case of Ti+B addition where poisoning i.e. coarsening of the grains has occurred. Regarding the addition of these element on the mechanical behavior; it was found that addition of Ti Or Ti+B resulted in little enhancement of the alloy strength factor and its flow stress at 20% true strain; whereas, the addition of resulted in deteriorating of its mechanical behavior as % decrease in the strength factor and % in its flow stress of 20%. As for the strain hardening index; addition of any of these elements resulted in decreasing the strain hardening index.

Keywords: addition, grain refinement, mechanical characteristics, microstructure, rare earth elements, ZA-22, Zinc- aluminum alloy

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Authors: Imad M. Assali

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Recently, the world main problem is a global warming and climate change affecting both outdoor and indoor environments, especially the air quality (AQ) as a result of vast migration of people from rural areas to urban areas. Therefore, cities became more crowded and denser from an irregular population increase, along with increasing urbanization caused many problems for the environment such as increasing the land prices, changes in life style, and the new buildings are not adapted to the climate producing uncomfortable and unhealthy indoor building conditions. As interior environments are the places that create the most intimate relationship with the user. Consequently, the indoor environment quality (IEQ) for buildings became uncomfortable and unhealthy for its occupants. The symptoms commonly associated with poor indoor environment such as itchy, headache, fatigue, and respiratory complaints such as cough and congestion, etc. The symptoms tend to improve over time or even disappear when people are away from the building. Therefore, designing a healthy indoor environment to fulfill human needs is the main concern for architects and interior designer. However, this research explores how occupant expectations and environmental attitudes may influence occupant health and satisfaction within the context of the indoor environment. In doing so, it reviews and contributes to the methods and tools used to evaluate only the indoor environment quality (IEQ) components of building performance. Its main aim is to review the literature on indoor human comfort. This is followed by a review of previous papers published related to human comfort. Finally, this paper will provide possible approaches in design level of healthy buildings.

Keywords: sustainable building, indoor environment quality (IEQ), occupant's health, active system, sick building syndrome (SBS)

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Authors: Shivankar Agrawal, Sunil Kumar Deshmukh, Colin Barrow, Alok Adholeya

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Millions of people worldwide are affected by infectious diseases caused by bacteria and fungi. Skin and skin structure infections (SSSI) represent a significant category of infectious disease. Unexpectedly, many pathogens have developed resistance towards current antibiotics and over the time this problem has become more and more serious. All these new problems necessitate the continuous search for novel and alternative antibiotics and antifungals. The aim of our research is the screening of extracts of marine fungi for their antibacterial activity against bacteria causing skin and wound infection in humans. A total of 40 marine samples were collected from west coast and Andaman Island of India and 35 morphologically different marine fungi were isolated using natural sea water medium. Among 35 marine fungi, eight isolates exhibited significant antimicrobial activity against human pathogens. In the course of systematic screening program for bioactive marine fungi, strain 'D5' was found to be most potent strain with MIC value of 1 mg/mL, which was morphologically identified as Simplicillium lamellicola. The effects of the most active crude extracts against their susceptible test microorganisms were also investigated by SEM analysis. Purification and characterization of crude extracts for identification of active lead molecule is under process. The results of diversity and antimicrobial activity have increased the scope of finding industrially important marine fungi from Indian marine environments and these organisms could be vital sources for the discovery of pharmaceutically useful molecules.

Keywords: antimicrobial activity, antibiotic, marine fungi, skin infections

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Authors: Ishraq M. Anjum

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Distributed Bragg reflectors are used in vertical-cavity surface-emitting lasers (VCSELs) in order to achieve very high reflectivity. Use of metamaterial in place of distributed Bragg reflector can reduce the device size significantly. A silicon-based metamaterial near perfect reflector is designed to be used in place of distributed Bragg reflectors in VCSELs. Mie resonance in dielectric microparticles is exploited in order to design the metamaterial. A reflectivity of 98.31% is achieved using finite-difference time-domain method. An 808nm double intra-cavity contacted VCSEL structure with 1.5 λ cavity is proposed using this metamaterial near perfect reflector. The active region is designed to be composed of seven GaAs/AlGaAs quantum wells. Upon numerical investigation of the designed VCSEL structure, the threshold current is found to be 2.96 mA at an aperture of 40 square micrometers and the maximum output power is found to be 71 mW at a current of 141 mA. Miniaturization of conventional VCSELs is possible using this design.

Keywords: GaAs, LASER, metamaterial, VCSEL, vertical cavity surface emitting laser

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Authors: Redrisse Djoumessi Fobasso, Baidyanath Sahu, Andre M. Strydom

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The R₂TX₃ (R = rare-earth, T = transition, and X = s and p block element) series of compounds are interesting owing to their fascinating structural and magnetic properties. In this present work, we have studied the magnetic and physical properties of the new Gd₂AgSi₃ polycrystalline compound. The sample was synthesized by the arc-melting method and confirmed to crystallize in the tetragonal α-ThSi₂-type crystal structure with space group I4/amd. Dc– and ac–magnetic susceptibility, specific heat, electrical resistivity, and magnetoresistance measurements were performed on the new compound. The structure provides a unique position in the unit cell for the magnetic trivalent Gd ion. Two magnetic phase transitions were consistently found in dc- and ac-magnetic susceptibility, heat capacity, and electrical resistivity at temperatures Tₙ₁ = 11 K and Tₙ₂ = 20 K, which is an indication of the complex magnetic behavior in this compound. The compound is found to be metamagnetic over a range of temperatures below and above Tₙ₁. From field-dependent electrical resistivity, it is confirmed that the compound shows unusual negative magnetoresistance in the antiferromagnetically ordered region. These results contribute to a better understanding of this class of materials.

Keywords: complex magnetic behavior, metamagnetic, negative magnetoresistance, two magnetic phase transitions

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Authors: Tianyang Xu

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Small underwater targets generally have a non-centrosymmetric geometry, and the acoustic scattering field of the target has spatial inhomogeneity under active sonar detection conditions. In view of the above problems, this paper takes the hemispherical cylindrical shell as the research object, and considers the angle continuity implied in the echo characteristics, and proposes a cluster-driven research method for the non-uniform characteristics of target echo angle. First, the target echo features are extracted, and feature vectors are constructed. Secondly, the t-SNE algorithm is used to improve the internal connection of the feature vector in the low-dimensional feature space and to construct the visual feature space. Finally, the implicit angular relationship between echo features is extracted under unsupervised condition by cluster analysis. The reconstruction results of the local geometric structure of the target corresponding to different categories show that the method can effectively divide the angle interval of the local structure of the target according to the natural acoustic scattering characteristics of the target.

Keywords: underwater target;, non-uniform characteristics;, cluster-driven method;, acoustic scattering characteristics

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Authors: H. S. Haroyan, V. R. Tadevosyan

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High gain broadband plasmonic slot nano-antenna has been considered. The theory of plasmonic slot nano-antenna (PSNA) has been developed. The analytical model takes into account also the electrical field inside the metal due to imperfectness of metal in optical range, as well as numerical investigation based on FEM method has been realized. It should be mentioned that Yagi-Uda configuration improves directivity in the plane of structure. In contrast, in this paper the possibility of directivity improvement of proposed PSNA in perpendicular plane of structure by using reflection metallic surface placed under the slot in fixed distance has been demonstrated. It is well known that a directivity improvement brings to the antenna gain increasing. This method of diagram improving is also well known from RF antenna design theory. Moreover the improvement of directivity in the perpendicular plane gives more flexibility in such application as improving the light and atom, ion, molecule interactions by using such type of plasmonic slot antenna. By the analogy of dipole type optical antennas the widening of working wavelengths has been realized by using bowtie geometry of slots, which made the antenna broadband.

Keywords: broadband antenna, high gain, slot nano-antenna, plasmonics.

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Authors: Al-Amin, Huanjun Jiang, Anayat Ali

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Reinforced concrete frames (RC), especially Ordinary RC frames, are prone to structural failures/collapse during seismic events, leading to a large proportion of debris from the structures, which obstructs adjacent areas, including streets. These blocked areas severely impede post-earthquake resilience. This study uses computational simulation (FEM) to investigate the amount of debris generated by the seismic collapse of an ordinary reinforced concrete moment frame building and its effects on the adjacent pedestrian and road network. A three-story ordinary reinforced concrete frame building, primarily designed for gravity load and earthquake resistance, was selected for analysis. Sixteen different ground motions were applied and scaled up until the total collapse of the tested building to evaluate the failure mode under various seismic events. Four types of collapse direction were identified through the analysis, namely aligned (positive and negative) and skewed (positive and negative), with aligned collapse being more predominant than skewed cases. The amount and distribution of debris around the collapsed building were assessed to investigate the interaction between collapsed buildings and adjacent street networks. An interaction was established between a building that collapsed in an aligned direction and the adjacent pedestrian walkway and narrow street located in an unplanned old city. The FEM model was validated against an existing shaking table test. The presented results can be utilized to simulate the interdependency between the debris generated from the collapse of seismic-prone buildings and the resilience of street networks. These findings provide insights for better disaster planning and resilient infrastructure development in earthquake-prone regions.

Keywords: building collapse, earthquake-induced debris, ORC moment resisting frame, street network

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Authors: Nesreddine Djafar Henni, Nassim Djedoui, Rachid Chebili

Abstract:

Recent decades have witnessed significant efforts being made to optimize different types of structures and components. The concept of cost optimization in reinforced concrete structures, which aims at minimizing financial resources while ensuring maximum building safety, comprises multiple materials, and the objective function for their optimal design is derived from the construction cost of the steel as well as concrete that significantly contribute to the overall weight of reinforced concrete (RC) structures. To achieve this objective, this work has been devoted to optimizing the structural design of 3D RC frame buildings which integrates, for the first time, the Algerian regulations. Three different test examples were investigated to assess the efficiency of our work in optimizing RC frame buildings. The hybrid GWOPSO algorithm is used, and 30000 generations are made. The cost of the building is reduced by iteration each time. Concrete and reinforcement bars are used in the building cost. As a result, the cost of a reinforced concrete structure is reduced by 30% compared with the initial design. This result means that the 3D cost-design optimization of the framed structure is successfully achieved.

Keywords: optimization, automation, API, Malab, RC structures

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Authors: Harshita Raj, Joydeep Ghosh, Rakesh L. Tanna, Prabal K. Chattopadhyay, K. A. Jadeja, Sharvil Patel, Kaushal M. Patel, Narendra C. Patel, S. B. Bhatt, V. K. Panchal, Chhaya Chavda, C. N. Gupta, D. Raju, S. K. Jha, J. Raval, S. Joisa, S. Purohit, C. V. S. Rao, P. K. Atrey, Umesh Nagora, R. Manchanda, M. B. Chowdhuri, Nilam Ramaiya, S. Banerjee, Y. C. Saxena

Abstract:

Efficient gas fueling is a critical aspect that needs to be mastered in order to maintain plasma density, to carry out fusion. This requires a fair understanding of fuel recycling in order to optimize the gas fueling. In Aditya tokamak, multiple gas puffs are used in a precise and controlled manner, for hydrogen fueling during the flat top of plasma discharge which has been instrumental in achieving discharges with enhanced density as well as energy confinement time. Following each gas puff, we observe peaks in temporal profile of Hα emission, Soft X-ray (SXR) and chord averaged electron density in a number of discharges, indicating efficient gas fueling. Interestingly, Hα temporal profile exhibited an additional peak following the peak corresponding to each gas puff. These additional peak Hα appeared in between the two gas puffs, indicating the presence of a secondary hydrogen source apart from the gas puffs. A thorough investigation revealed that these secondary Hα peaks coincide with Hard X- ray bursts which come from the interaction of runaway electrons with vessel limiters. This leads to consider that the runaway electrons (REs), which hit the wall, in turn, bring out the absorbed hydrogen and oxygen from the wall and makes the interaction of REs with limiter a secondary hydrogen source. These observations suggest that runaway electron induced recycling should also be included in recycling particle source in the particle balance calculations in tokamaks. Observation of two Hα peaks associated with one gas puff and their roles in enhancing and maintaining plasma density in Aditya tokamak will be discussed in this paper.

Keywords: fusion, gas fueling, recycling, Tokamak, Aditya

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Authors: Ben Khayut, Lina Fabri, Maya Avikhana

Abstract:

The models of the modern Artificial Narrow Intelligence (ANI) cannot: a) independently and continuously function without of human intelligence, used for retraining and reprogramming the ANI’s models, and b) think, understand, be conscious, cognize, infer, and more in state of Uncertainty, and changes in situations, and environmental objects. To eliminate these shortcomings and build a new generation of Artificial Intelligence systems, the paper proposes a Conception, Model, and Method of Computational Psycholinguistic Cognitive Situational-Fuzzy Self-Controlled Brain and Mind System (CPCSFSCBMSUU) using a neural network as its computational memory, operating under uncertainty, and activating its functions by perception, identification of real objects, fuzzy situational control, forming images of these objects, modeling their psychological, linguistic, cognitive, and neural values of properties and features, the meanings of which are identified, interpreted, generated, and formed taking into account the identified subject area, using the data, information, knowledge, and images, accumulated in the Memory. The functioning of the CPCSFSCBMSUU is carried out by its subsystems of the: fuzzy situational control of all processes, computational perception, identifying of reactions and actions, Psycholinguistic Cognitive Fuzzy Logical Inference, Decision making, Reasoning, Systems Thinking, Planning, Awareness, Consciousness, Cognition, Intuition, Wisdom, analysis and processing of the psycholinguistic, subject, visual, signal, sound and other objects, accumulation and using the data, information and knowledge in the Memory, communication, and interaction with other computing systems, robots and humans in order of solving the joint tasks. To investigate the functional processes of the proposed system, the principles of Situational Control, Fuzzy Logic, Psycholinguistics, Informatics, and modern possibilities of Data Science were applied. The proposed self-controlled System of Brain and Mind is oriented on use as a plug-in in multilingual subject Applications.

Keywords: computational brain, mind, psycholinguistic, system, under uncertainty

Procedia PDF Downloads 177

Authors: N. Messai, A. Boumali

Abstract:

In this work, we aim to solve the two dimensional Kemmer equation including Dirac oscillator interaction term, in the background space-time generated by a cosmic string which is submitted to an uniform magnetic field. Eigenfunctions and eigenvalues of our problem have been found and the influence of the cosmic string space-time on the energy spectrum has been analyzed.

Keywords: Kemmer oscillator, cosmic string, Dirac oscillator, eigenfunctions

Procedia PDF Downloads 584

Authors: Ismail Becenen

Abstract:

Air pollution, a consequence of urbanization brought about by modern life, is as global as it is local and regional. Because of the adverse effects of air pollution on human health, air quality is given importance all over the world. According to the decision of the World Health Organization, clean air is the basic necessity for human health and well-being. It poses a very high risk especially for heart diseases and stroke cases. In this study, the positive effects of natural gas usage on air pollution in cities are explained by using literature scans and air pollution measurement values. Natural gas is cleaner than other types of fuel. It contains less sulfur and organic sulfur compounds. When natural gas burns, it does not leave ashes, it does not cause problems in the rubbish mountains. It's a clean fuel, it easily burns and shines. It is a burning gas that is easy and efficient. In addition, there is not a toxic effect for people in case of inhalation. As a result, the use of natural gas needs to be widespread to reduce air pollution around the world in order to provide a healthier life for people and the environment.

Keywords: natural gas, air pollution, sulfur dioxide, particulate matter, energy

Procedia PDF Downloads 196

Authors: Hassan Beigi Rizi, Harold Auradou, Lamine Hattali

Abstract:

Various industries, including civil engineering, automotive, aerospace, and biomedical fields, are currently seeking novel and innovative high-performance lightweight materials to reduce energy consumption. Inspired by the structure of Euplectella Aspergillum Glass Sponges (EA-sponge), 2D unit cells were created and fabricated using a Fused Filament Fabrication (FFF) process with Polylactic acid (PLA) filaments. The stiffness and strength of bio-inspired EA-sponge lattices were investigated both experimentally and numerically under uniaxial tensile loading and are compared to three standard square lattices with diagonal struts (Designs B and C) and non-diagonal struts (Design D) reinforcements. The aim is to establish predictive scaling laws models and examine the deformation mechanisms involved. The results indicated that for the EA-sponge structure, the relative moduli and yield strength scaled linearly with relative density, suggesting that the deformation mechanism is stretching-dominated. The Finite element analysis (FEA), with periodic boundary conditions for volumetric homogenization, confirms these trends and goes beyond the experimental limits imposed by the FFF printing process. Therefore, the stretching-dominated behavior, investigated from 0.1 to 0.5 relative density, demonstrate that the study of EA-sponge structure can be exploited for the realization of square lattice topologies that are stiff and strong and have attractive potential for lightweight structural applications. However, the FFF process introduces an accuracy limitation, with approximately 10% error, making it challenging to print structures with a relative density below 0.2. Future work could focus on exploring the impact of different printing materials on the performance of EA-sponge structures.

Keywords: bio-inspiration, lattice structures, fused filament fabrication, scaling laws

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Authors: Hyeon-Kyo Lim, Sang-Hun Byun

Abstract:

Risk assessment is carried out in most industrial plants for accident prevention, but there exists insufficient data for statistical decision making. It is commonly said that risk can be expressed as a product of consequence and likelihood of a corresponding hazard factor. Eventually, therefore, risk assessment involves human decision making which cannot be objective per se. This study was carried out to comprehend perceptive characteristics of human beings in industrial plants. Subjects were shown a set of illustrations describing scenes of industrial plants, and were asked to assess the risk of each scene with not only linguistic variables but also numeric scores in the aspect of consequence and likelihood. After that, their responses were formulated as fuzzy membership functions, and compared with those of university students who had no experience of industrial works. The results showed that risk level of industrial workers were lower than those of any other groups, which implied that the workers might generally have a tendency to neglect more hazard factors in their work fields.

Keywords: fuzzy, hazard, linguistic variable, risk assessment

Procedia PDF Downloads 255