Search results for: currency board arrangement
99 Roadmap to a Bottom-Up Approach Creating Meaningful Contributions to Surgery in Low-Income Settings
Authors: Eva Degraeuwe, Margo Vandenheede, Nicholas Rennie, Jolien Braem, Miryam Serry, Frederik Berrevoet, Piet Pattyn, Wouter Willaert, InciSioN Belgium Consortium
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Background: Worldwide, five billion people lack access to safe and affordable surgical care. An added 1.27 million surgeons, anesthesiologists, and obstetricians (SAO) are needed by 2030 to meet the target of 20 per 100,000 population and to reach the goal of the Lancet Commission on Global Surgery. A well-informed future generation exposed early on to the current challenges in global surgery (GS) is necessary to ensure a sustainable future. Methods: InciSioN, the International Student Surgical Network, is a non-profit organization by and for students, residents, and fellows in over 80 countries. InciSioN Belgium, one of the prominent national working groups, has made a vast progression and collaborated with other networks to fill the educational gap, stimulate advocacy efforts and increase interactions with the international network. This report describes a roadmap to achieve sustainable development and education within GS, with the example of InciSioN Belgium. Results: Since the establishment of the organization’s branch in 2019, it has hosted an educational workshop for first-year residents in surgery, engaging over 2500 participants, and established a recurring directing board of 15 members. In the year 2020-2021, InciSioN Ghent has organized three workshops combining educational and interactive sessions for future prime advocates and surgical candidates. InciSioN Belgium has set up a strong formal coalition with the Belgian Medical Students’ Association (BeMSA), with its own standing committee, reaching over 3000+ medical students annually. In 2021-2022, InciSioN Belgium broadened to a multidisciplinary approach, including dentistry and nursing students and graduates within workshops and research projects, leading to a member and exposure increase of 450%. This roadmap sets strategic goals and mechanisms for the GS community to achieve nationwide sustained improvements in the research and education of GS focused on future SAOs, in order to achieve the GS sustainable development goals. In the coming year, expansion is directed to a formal integration of GS into the medical curriculum and increased international advocacy whilst inspiring SAOs to integrate into GS in Belgium. Conclusion: The development and implementation of durable change for GS are necessary. The student organization InciSioN Belgium is growing and hopes to close the colossal gap in GS and inspire the growth of other branches while sharing the know-how of a student organization.Keywords: advocacy, education, global surgery, InciSioN, student network
Procedia PDF Downloads 17598 An Evaluation of the Auxiliary Instructional App Amid Learning Chinese Characters for Children with Specific Learning Disorders
Authors: Chieh-Ning Lan, Tzu-Shin Lin, Kun-Hao Lin
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Chinese handwriting skill is one of the basic skills of school-age children in Taiwan, which helps them to learn most academic subjects. Differ from the alphabetic language system, Chinese written language is a logographic script with a complicated 2-dimensional character structure as a morpheme. Visuospatial ability places a great role in Chinese handwriting to maintain good proportion and alignment of these interwoven strokes. In Taiwan, school-age students faced the challenge to recognize and write down Chinese characters, especially in children with written expression difficulties (CWWDs). In this study, we developed an instructional app to help CWWDs practice Chinese handwriting skills, and we aimed to apply the mobile assisted language learning (MALL) system in clinical writing strategies. To understand the feasibility and satisfaction of this auxiliary instructional writing app, we investigated the perceive and value both from school-age students and the clinic therapists, who were the target users and the experts. A group of 8 elementary school children, as well as 8 clinic therapists, were recruited. The school-age students were asked to go through a paper-based instruction and were asked to score the visual expression based on their graphic preference; the clinic therapists were asked to watch an introductive video of this instructional app and complete the online formative questionnaire. In the results of our study, from the perspective of user interface design, school-age students were more attracted to cartoon-liked pictures rather than line drawings or vivid photos. Moreover, compared to text, pictures which have higher semantic transparency were more commonly chosen by children. In terms of the quantitative survey from clinic therapists, they were highly satisfied with this auxiliary instructional writing app, including the concepts such as visual design, teaching contents, and positive reinforcement system. Furthermore, the qualitative results also suggested comprehensive positive feedbacks on the teaching contents and the feasibility of integrating the app into clinical treatments. Interestingly, we found that clinic therapists showed high agreement in approving CWWDs’ writing ability with using orthographic knowledge; however, in the qualitative section, clinic therapists pointed out that CWWDs usually have relative insufficient background knowledge in Chinese character orthographic rules, which because it is not a key-point in conventional handwriting instruction. Also, previous studies indicated that conventional Chinese reading and writing instructions were lacked of utilizing visual-spatial arrangement strategies. Based on the sharing experiences from all participants, we concluded several interesting topics that are worth to dedicate to in the future. In this undergoing app system, improvement and revision will be applied into the system design, and will establish a better and more useful instructional system for CWWDs within their treatments; enlightened by the opinions related to learning content, the importance of orthographic knowledge in Chinese character recognition should be well discussed and involved in CWWDs’ intervention in the future.Keywords: auxiliary instructional app, children with writing difficulties, Chinese handwriting, orthographic knowledge
Procedia PDF Downloads 17497 Office Workspace Design for Policewomen in Assam, India: Applications for Developing Countries
Authors: Shilpi Bora, Abhirup Chatterjee, Debkumar Chakrabarti
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Organizations of all the sectors around the world are increasingly revisiting their workplace strategies with due concern for women working therein. Limited office space and rigid work arrangements contribute to lesser job satisfaction and greater work impoundments for any organization. Flexible workspace strategies are indispensable to accommodate the progressive rise of modular workstations and involvement of women. Today’s generation of employees deserves malleable office environments with employee-friendly job conditions and strategies. The workplace nowadays stands on rapid organizational changes in progressive and flexible work culture. Occupational well-being practices need to keep pace with the rapid changes in office-based work. Working at the office (workspace) with awkward postures or for long periods can cause pain, discomfort, and injury. The world is stirring towards the era of globalization and progress. The 4000 women police personnel constitute less than one per cent of the total police strength of India. Lots of innovative fields are growing fast, and it is important that we should accommodate women in those arenas. The timeworn trends should be set apart to set out for fresh opportunities and possibilities of development and success through more involvement of women in the workplace. The notion of women policing is gaining position throughout the world, and various countries are putting solemn efforts to mainstream women in policing. As the role of women policing in a society is budding, and thus it is also notable that the accessibility of women at general police stations should be considered. Accordingly, the impact of workspace at police station on the employee productivity has been widely deliberated as a crucial contributor to employee satisfaction leading to better functional motivation. Thus the present research aimed to look into the office workstation design of police station with reference to womanhood specific issues to uplift occupational wellbeing of the policewomen. Personal interview and individual responses collected through administering to a subjective assessment questionnaire on thirty women police as well as to have their views on these issues by purposive non-probability sampling of women police personnel of different ranks posted in Guwahati, Assam, India. Scrutiny of the collected data revealed that office design has a substantial impact on the policewomen job satisfaction in the police station. In this study, the workspace was designed in such a way that the set of factors would impact on the individual to ensure increased productivity. Office design such as furniture, noise, temperature, lighting and spatial arrangement were considered. The primary feature which affected the productivity of policewomen was the furniture used in the workspace, which was found to disturb the everyday and overall productivity of policewomen. Therefore, it was recommended to have proper and adequate ergonomics design intervention to improve the office design for better performance. This type of study is today’s need-of-the-hour to empower women and facilitate their inner talent to come up in service of the nation. The office workspace design also finds critical importance at several other occupations also – where office workstation needs further improvement.Keywords: office workspace design, policewomen, womanhood concerns at workspace, occupational wellbeing
Procedia PDF Downloads 22596 Solar Electric Propulsion: The Future of Deep Space Exploration
Authors: Abhishek Sharma, Arnab Banerjee
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The research is intended to study the solar electric propulsion (SEP) technology for planetary missions. The main benefits of using solar electric propulsion for such missions are shorter flight times, more frequent target accessibility and the use of a smaller launch vehicle than that required by a comparable chemical propulsion mission. Energized by electric power from on-board solar arrays, the electrically propelled system uses 10 times less propellant than conventional chemical propulsion system, yet the reduced fuel mass can provide vigorous power which is capable of propelling robotic and crewed missions beyond the Lower Earth Orbit (LEO). The various thrusters used in the SEP are gridded ion thrusters and the Hall Effect thrusters. The research is solely aimed to study the ion thrusters and investigate the complications related to it and what can be done to overcome the glitches. The ion thrusters are used because they are found to have a total lower propellant requirement and have substantially longer time. In the ion thrusters, the anode pushes or directs the incoming electrons from the cathode. But the anode is not maintained at a very high potential which leads to divergence. Divergence leads to the charges interacting against the surface of the thruster. Just as the charges ionize the xenon gases, they are capable of ionizing the surfaces and over time destroy the surface and hence contaminate it. Hence the lifetime of thruster gets limited. So a solution to this problem is using substances which are not easy to ionize as the surface material. Another approach can be to increase the potential of anode so that the electrons don’t deviate much or reduce the length of thruster such that the positive anode is more effective. The aim is to work on these aspects as to how constriction of the deviation of charges can be done by keeping the input power constant and hence increase the lifetime of the thruster. Predominantly ring cusp magnets are used in the ion thrusters. However, the study is also intended to observe the effect of using solenoid for producing micro-solenoidal magnetic field apart from using the ring cusp magnetic field which are used in the discharge chamber for prevention of interaction of electrons with the ionization walls. Another foremost area of interest is what are the ways by which power can be provided to the Solar Electric Propulsion Vehicle for lowering and boosting the orbit of the spacecraft and also provide substantial amount of power to the solenoid for producing stronger magnetic fields. This can be successfully achieved by using the concept of Electro-dynamic tether which will serve as a power source for powering both the vehicle and the solenoids in the ion thruster and hence eliminating the need for carrying extra propellant on the spacecraft which will reduce the weight and hence reduce the cost of space propulsion.Keywords: electro-dynamic tether, ion thruster, lifetime of thruster, solar electric propulsion vehicle
Procedia PDF Downloads 21195 Collaboration between Grower and Research Organisations as a Mechanism to Improve Water Efficiency in Irrigated Agriculture
Authors: Sarah J. C. Slabbert
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The uptake of research as part of the diffusion or adoption of innovation by practitioners, whether individuals or organisations, has been a popular topic in agricultural development studies for many decades. In the classical, linear model of innovation theory, the innovation originates from an expert source such as a state-supported research organisation or academic institution. The changing context of agriculture led to the development of the agricultural innovation systems model, which recognizes innovation as a complex interaction between individuals and organisations, which include private industry and collective action organisations. In terms of this model, an innovation can be developed and adopted without any input or intervention from a state or parastatal research organisation. This evolution in the diffusion of agricultural innovation has put forward new challenges for state or parastatal research organisations, which have to demonstrate the impact of their research to the legislature or a regulatory authority: Unless the organisation and the research it produces cross the knowledge paths of the intended audience, there will be no awareness, no uptake and certainly no impact. It is therefore critical for such a research organisation to base its communication strategy on a thorough understanding of the knowledge needs, information sources and knowledge networks of the intended target audience. In 2016, the South African Water Research Commission (WRC) commissioned a study to investigate the knowledge needs, information sources and knowledge networks of Water User Associations and commercial irrigators with the aim of improving uptake of its research on efficient water use in irrigation. The first phase of the study comprised face-to-face interviews with the CEOs and Board Chairs of four Water User Associations along the Orange River in South Africa, and 36 commercial irrigation farmers from the same four irrigation schemes. Intermediaries who act as knowledge conduits to the Water User Associations and the irrigators were identified and 20 of them were subsequently interviewed telephonically. The study found that irrigators interact regularly with grower organisations such as SATI (South African Table Grape Industry) and SAPPA (South African Pecan Nut Association) and that they perceive these organisations as credible, trustworthy and reliable, within their limitations. State and parastatal research institutions, on the other hand, are associated with a range of negative attributes. As a result, the awareness of, and interest in, the WRC and its research on water use efficiency in irrigated agriculture are low. The findings suggest that a communication strategy that involves collaboration with these grower organisations would empower the WRC to participate much more efficiently and with greater impact in agricultural innovation networks. The paper will elaborate on the findings and discuss partnering frameworks and opportunities to manage perceptions and uptake.Keywords: agricultural innovation systems, communication strategy, diffusion of innovation, irrigated agriculture, knowledge paths, research organisations, target audiences, water use efficiency
Procedia PDF Downloads 11594 Verification of Low-Dose Diagnostic X-Ray as a Tool for Relating Vital Internal Organ Structures to External Body Armour Coverage
Authors: Natalie A. Sterk, Bernard van Vuuren, Petrie Marais, Bongani Mthombeni
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Injuries to the internal structures of the thorax and abdomen remain a leading cause of death among soldiers. Body armour is a standard issue piece of military equipment designed to protect the vital organs against ballistic and stab threats. When configured for maximum protection, the excessive weight and size of the armour may limit soldier mobility and increase physical fatigue and discomfort. Providing soldiers with more armour than necessary may, therefore, hinder their ability to react rapidly in life-threatening situations. The capability to determine the optimal trade-off between the amount of essential anatomical coverage and hindrance on soldier performance may significantly enhance the design of armour systems. The current study aimed to develop and pilot a methodology for relating internal anatomical structures with actual armour plate coverage in real-time using low-dose diagnostic X-ray scanning. Several pilot scanning sessions were held at Lodox Systems (Pty) Ltd head-office in South Africa. Testing involved using the Lodox eXero-dr to scan dummy trunk rigs at various degrees and heights of measurement; as well as human participants, wearing correctly fitted body armour while positioned in supine, prone shooting, seated and kneeling shooting postures. The verification of sizing and metrics obtained from the Lodox eXero-dr were then confirmed through a verification board with known dimensions. Results indicated that the low-dose diagnostic X-ray has the capability to clearly identify the vital internal structures of the aortic arch, heart, and lungs in relation to the position of the external armour plates. Further testing is still required in order to fully and accurately identify the inferior liver boundary, inferior vena cava, and spleen. The scans produced in the supine, prone, and seated postures provided superior image quality over the kneeling posture. The X-ray-source and-detector distance from the object must be standardised to control for possible magnification changes and for comparison purposes. To account for this, specific scanning heights and angles were identified to allow for parallel scanning of relevant areas. The low-dose diagnostic X-ray provides a non-invasive, safe, and rapid technique for relating vital internal structures with external structures. This capability can be used for the re-evaluation of anatomical coverage required for essential protection while optimising armour design and fit for soldier performance.Keywords: body armour, low-dose diagnostic X-ray, scanning, vital organ coverage
Procedia PDF Downloads 12493 Pre-Cooling Strategies for the Refueling of Hydrogen Cylinders in Vehicular Transport
Authors: C. Hall, J. Ramos, V. Ramasamy
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Hydrocarbon-based fuel vehicles are a major contributor to air pollution due to harmful emissions produced, leading to a demand for cleaner fuel types. A leader in this pursuit is hydrogen, with its application in vehicles producing zero harmful emissions and the only by-product being water. To compete with the performance of conventional vehicles, hydrogen gas must be stored on-board of vehicles in cylinders at high pressures (35–70 MPa) and have a short refueling duration (approximately 3 mins). However, the fast-filling of hydrogen cylinders causes a significant rise in temperature due to the combination of the negative Joule-Thompson effect and the compression of the gas. This can lead to structural failure and therefore, a maximum allowable internal temperature of 85°C has been imposed by the International Standards Organization. The technological solution to tackle the issue of rapid temperature rise during the refueling process is to decrease the temperature of the gas entering the cylinder. Pre-cooling of the gas uses a heat exchanger and requires energy for its operation. Thus, it is imperative to determine the least amount of energy input that is required to lower the gas temperature for cost savings. A validated universal thermodynamic model is used to identify an energy-efficient pre-cooling strategy. The model requires negligible computational time and is applied to previously validated experimental cases to optimize pre-cooling requirements. The pre-cooling characteristics include the location within the refueling timeline and its duration. A constant pressure-ramp rate is imposed to eliminate the effects of rapid changes in mass flow rate. A pre-cooled gas temperature of -40°C is applied, which is the lowest allowable temperature. The heat exchanger is assumed to be ideal with no energy losses. The refueling of the cylinders is modeled with the pre-cooling split in ten percent time intervals. Furthermore, varying burst durations are applied in both the early and late stages of the refueling procedure. The model shows that pre-cooling in the later stages of the refuelling process is more energy-efficient than early pre-cooling. In addition, the efficiency of pre-cooling towards the end of the refueling process is independent of the pressure profile at the inlet. This leads to the hypothesis that pre-cooled gas should be applied as late as possible in the refueling timeline and at very low temperatures. The model had shown a 31% reduction in energy demand whilst achieving the same final gas temperature for a refueling scenario when pre-cooling was applied towards the end of the process. The identification of the most energy-efficient refueling approaches whilst adhering to the safety guidelines is imperative to reducing the operating cost of hydrogen refueling stations. Heat exchangers are energy-intensive and thus, reducing the energy requirement would lead to cost reduction. This investigation shows that pre-cooling should be applied as late as possible and for short durations.Keywords: cylinder, hydrogen, pre-cooling, refueling, thermodynamic model
Procedia PDF Downloads 9992 Multiple Plant-Based Cell Suspension as a Bio-Ink for 3D Bioprinting Applications in Food Technology
Authors: Yusuf Hesham Mohamed
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Introduction: Three-dimensional printing technology includes multiple procedures that fabricate three-dimensional objects through consecutively layering two-dimensional cross-sections on top of each other. 3D bioprinting is a promising field of 3D printing, which fabricates tissues and organs by accurately controlling the proper arrangement of diverse biological components. 3D bioprinting uses software and prints biological materials and their supporting components layer-by-layer on a substrate or in a tissue culture plate to produce complex live tissues and organs. 3D food printing is an emerging field of 3D bioprinting in which the 3D printed products are food products that are cheap, require less effort to produce, and have more desirable traits. The Aim of the Study is the development of an affordable 3D bioprinter by altering a locally made CNC instrument with an open-source platform to suit the 3D bio-printer purposes. Later, we went through applying the prototype in several applications regarding food technology and drug testing, including the organ-On-Chip. Materials and Methods: An off-the-shelf 3D printer was modified by designing and fabricating the syringe unit, which was designed on the basis of the Milli-fluidics system. Sodium alginate and gelatin hydrogels were prepared, followed by leaf cell suspension preparation from narrow sections of Fragaria’s viable leaves. The desired 3D structure was modeled, and 3D printing preparations took place. Cell-free and cell-laden hydrogels were printed at room temperature under sterile conditions. Post printing curing process was performed. The printed structure was further studied. Results: Positive results have been achieved using the altered 3D bioprinter where a 3D hydrogel construct of two layers made of the combination of sodium alginate to gelatin (15%: 0.5%) has been printed. DLP 3D printer was used to design the syringe component with a transparent PLA-Pro resin for the creation of a microfluidics system having two channels altered to the double extruder. The hydrogel extruder’s design was based on peristaltic pumps, which utilized a stepper motor. The design and fabrication were made using DIY-3D printed parts. Hard plastic PLA was the material utilized for printing. SEM was used to carry out the porous 3D construct imaging. Multiple physical and chemical tests were performed in order to ensure that the cell line was suitable for hosting. Fragaria plant was developed by suspending Fragaria’s cells from its leaves using the 3D bioprinter. Conclusion: 3D bioprinting is considered to be an emerging scientific field that can facilitate and improve many scientific tests and studies. Thus, having a 3D bioprinter in labs is considered to be an essential requirement. 3D bioprinters are very expensive; however, the fabrication of a 3D printer into a 3D bioprinter can lower the cost of the bioprinter. The 3D bioprinter implemented made use of peristaltic pumps instead of syringe-based pumps in order to extend the ability to print multiple types of materials and cells.Keywords: scaffold, eco on chip, 3D bioprinter, DLP printer
Procedia PDF Downloads 12091 Analysis of Shrinkage Effect during Mercerization on Himalayan Nettle, Cotton and Cotton/Nettle Yarn Blends
Authors: Reena Aggarwal, Neha Kestwal
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The Himalayan Nettle (Girardinia diversifolia) has been used for centuries as fibre and food source by Himalayan communities. Himalayan Nettle is a natural cellulosic fibre that can be handled in the same way as other cellulosic fibres. The Uttarakhand Bamboo and Fibre Development Board based in Uttarakhand, India is working extensively with the nettle fibre to explore the potential of nettle for textile production in the region. The fiber is a potential resource for rural enterprise development for some high altitude pockets of the state and traditionally the plant fibre is used for making domestic products like ropes and sacks. Himalayan Nettle is an unconventional natural fiber with functional characteristics of shrink resistance, degree of pathogen and fire resistance and can blend nicely with other fibres. Most importantly, they generate mainly organic wastes and leave residues that are 100% biodegradable. The fabrics may potentially be reused or re-manufactured and can also be used as a source of cellulose feedstock for regenerated cellulosic products. Being naturally bio- degradable, the fibre can be composted if required. Though a lot of research activities and training are directed towards fibre extraction and processing techniques in different craft clusters villagers of different clusters of Uttarkashi, Chamoli and Bageshwar of Uttarakhand like retting and Degumming process, very little is been done to analyse the crucial properties of nettle fiber like shrinkage and wash fastness. These properties are very crucial to obtain desired quality of fibre for further processing of yarn making and weaving and in developing these fibers into fine saleable products. This research therefore is focused towards various on-field experiments which were focused on shrinkage properties conducted on cotton, nettle and cotton/nettle blended yarn samples. The objective of the study was to analyze the scope of the blended fiber for developing into wearable fabrics. For the study, after conducting the initial fiber length and fineness testing, cotton and nettle fibers were mixed in 60:40 ratio and five varieties of yarns were spun in open end spinning mill having yarn count of 3s, 5s, 6s, 7s and 8s. Samples of 100% Nettle 100% cotton fibers in 8s count were also developed for the study. All the six varieties of yarns were tested with shrinkage test and results were critically analyzed as per ASTM method D2259. It was observed that 100% Nettle has a least shrinkage of 3.36% while pure cotton has shrinkage approx. 13.6%. Yarns made of 100% Cotton exhibits four times more shrinkage than 100% Nettle. The results also show that cotton and Nettle blended yarn exhibit lower shrinkage than 100% cotton yarn. It was thus concluded that as the ratio of nettle increases in the samples, the shrinkage decreases in the samples. These results are very crucial for Uttarakhand people who want to commercially exploit the abundant nettle fiber for generating sustainable employment.Keywords: Himalayan nettle, sustainable, shrinkage, blending
Procedia PDF Downloads 24290 Modeling the Relation between Discretionary Accrual Earnings Management, International Financial Reporting Standards and Corporate Governance
Authors: Ikechukwu Ndu
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This study examines the econometric modeling of the relation between discretionary accrual earnings management, International Financial Reporting Standards (IFRS), and certain corporate governance factors with regard to listed Nigerian non-financial firms. Although discretionary accrual earnings management is a well-known and global problem that has an adverse impact on users of the financial statements, its relationship with IFRS and corporate governance is neither adequately researched nor properly systematically investigated in Nigeria. The dearth of research in the relation between discretionary accrual earnings management, IFRS and corporate governance in Nigeria has made it difficult for academics, practitioners, government setting bodies, regulators and international bodies to achieve a clearer understanding of how discretionary accrual earnings management relates to IFRS and certain corporate governance characteristics. This is the first study to the author’s best knowledge to date that makes interesting research contributions that significantly add to the literature of discretionary accrual earnings management and its relation with corporate governance and IFRS pertaining to the Nigerian context. A comprehensive review is undertaken of the literature of discretionary total accrual earnings management, IFRS, and certain corporate governance characteristics as well as the data, models, methodologies, and different estimators used in the study. Secondary financial statement, IFRS, and corporate governance data are sourced from Bloomberg database and published financial statements of Nigerian non-financial firms for the period 2004 to 2016. The methodology uses both the total and working capital accrual basis. This study has a number of interesting preliminary findings. First, there is a negative relationship between the level of discretionary accrual earnings management and the adoption of IFRS. However, this relationship does not appear to be statistically significant. Second, there is a significant negative relationship between the size of the board of directors and discretionary accrual earnings management. Third, CEO Separation of roles does not constrain earnings management, indicating the need to preserve relationships, personal connections, and maintain bonded friendships between the CEO, Chairman, and executive directors. Fourth, there is a significant negative relationship between discretionary accrual earnings management and the use of a Big Four firm as an auditor. Fifth, including shareholders in the audit committee, leads to a reduction in discretionary accrual earnings management. Sixth, the debt and return on assets (ROA) variables are significant and positively related to discretionary accrual earnings management. Finally, the company size variable indicated by the log of assets is surprisingly not found to be statistically significant and indicates that all Nigerian companies irrespective of size engage in discretionary accrual management. In conclusion, this study provides key insights that enable a better understanding of the relationship between discretionary accrual earnings management, IFRS, and corporate governance in the Nigerian context. It is expected that the results of this study will be of interest to academics, practitioners, regulators, governments, international bodies and other parties involved in policy setting and economic development in areas of financial reporting, securities regulation, accounting harmonization, and corporate governance.Keywords: discretionary accrual earnings management, earnings manipulation, IFRS, corporate governance
Procedia PDF Downloads 14589 Problem Solving in Mathematics Education: A Case Study of Nigerian Secondary School Mathematics Teachers’ Conceptions in Relation to Classroom Instruction
Authors: Carol Okigbo
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Mathematical problem solving has long been accorded an important place in mathematics curricula at every education level in both advanced and emerging economies. Its classroom approaches have varied, such as teaching for problem-solving, teaching about problem-solving, and teaching mathematics through problem-solving. It requires engaging in tasks for which the solution methods are not eminent, making sense of problems and persevering in solving them by exhibiting processes, strategies, appropriate attitude, and adequate exposure. Teachers play important roles in helping students acquire competency in problem-solving; thus, they are expected to be good problem-solvers and have proper conceptions of problem-solving. Studies show that teachers’ conceptions influence their decisions about what to teach and how to teach. Therefore, how teachers view their roles in teaching problem-solving will depend on their pedagogical conceptions of problem-solving. If teaching problem-solving is a major component of secondary school mathematics instruction, as recommended by researchers and mathematics educators, then it is necessary to establish teachers’ conceptions, what they do, and how they approach problem-solving. This study is designed to determine secondary school teachers’ conceptions regarding mathematical problem solving, its current situation, how teachers’ conceptions relate to their demographics, as well as the interaction patterns in the mathematics classroom. There have been many studies of mathematics problem solving, some of which addressed teachers’ conceptions using single-method approaches, thereby presenting only limited views of this important phenomenon. To address the problem more holistically, this study adopted an integrated mixed methods approach which involved a quantitative survey, qualitative analysis of open-ended responses, and ethnographic observations of teachers in class. Data for the analysis came from a random sample of 327 secondary school mathematics teachers in two Nigerian states - Anambra State and Enugu State who completed a 45-item questionnaire. Ten of the items elicited demographic information, 11 items were open-ended questions, and 25 items were Likert-type questions. Of the 327 teachers who responded to the questionnaires, 37 were randomly selected and observed in their classes. Data analysis using ANOVA, t-tests, chi-square tests, and open coding showed that the teachers had different conceptions about problem-solving, which fall into three main themes: practice on exercises and word application problems, a process of solving mathematical problems, and a way of teaching mathematics. Teachers reported that no period is set aside for problem-solving; typically, teachers solve problems on the board, teach problem-solving strategies, and allow students time to struggle with problems on their own. The result shows a significant difference between male and female teachers’ conception of problems solving, a significant relationship among teachers’ conceptions and academic qualifications, and teachers who have spent ten years or more teaching mathematics were significantly different from the group with seven to nine years of experience in terms of their conceptions of problem-solving.Keywords: conceptions, education, mathematics, problem solving, teacher
Procedia PDF Downloads 7688 Development and Experimental Evaluation of a Semiactive Friction Damper
Authors: Juan S. Mantilla, Peter Thomson
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Seismic events may result in discomfort on occupants of the buildings, structural damage or even buildings collapse. Traditional design aims to reduce dynamic response of structures by increasing stiffness, thus increasing the construction costs and the design forces. Structural control systems arise as an alternative to reduce these dynamic responses. A commonly used control systems in buildings are the passive friction dampers, which adds energy dissipation through damping mechanisms induced by sliding friction between their surfaces. Passive friction dampers are usually implemented on the diagonal of braced buildings, but such devices have the disadvantage that are optimal for a range of sliding force and out of that range its efficiency decreases. The above implies that each passive friction damper is designed, built and commercialized for a specific sliding/clamping force, in which the damper shift from a locked state to a slip state, where dissipates energy through friction. The risk of having a variation in the efficiency of the device according to the sliding force is that the dynamic properties of the building can change as result of many factor, even damage caused by a seismic event. In this case the expected forces in the building can change and thus considerably reduce the efficiency of the damper (that is designed for a specific sliding force). It is also evident than when a seismic event occurs the forces in each floor varies in the time what means that the damper's efficiency is not the best at all times. Semi-Active Friction devices adapt its sliding force trying to maintain its motion in the slipping phase as much as possible, because of this, the effectiveness of the device depends on the control strategy used. This paper deals with the development and performance evaluation of a low cost Semiactive Variable Friction Damper (SAVFD) in reduced scale to reduce vibrations of structures subject to earthquakes. The SAVFD consist in a (1) hydraulic brake adapted to (2) a servomotor which is controlled with an (3) Arduino board and acquires accelerations or displacement from (4) sensors in the immediately upper and lower floors and a (5) power supply that can be a pair of common batteries. A test structure, based on a Benchmark structure for structural control, was design and constructed. The SAVFD and the structure are experimentally characterized. A numerical model of the structure and the SAVFD is developed based on the dynamic characterization. Decentralized control algorithms were modeled and later tested experimentally using shaking table test using earthquake and frequency chirp signals. The controlled structure with the SAVFD achieved reductions greater than 80% in relative displacements and accelerations in comparison to the uncontrolled structure.Keywords: earthquake response, friction damper, semiactive control, shaking table
Procedia PDF Downloads 37887 Buoyant Gas Dispersion in a Small Fuel Cell Enclosure: A Comparison Study Using Plain and Pressed Louvre Vent Passive Ventilation Schemes
Authors: T. Ghatauray, J. Ingram, P. Holborn
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The transition from a ‘carbon rich’ fossil fuel dependent to a ‘sustainable’ and ‘renewable’ hydrogen based society will see the deployment of hydrogen fuel cells (HFC) in transport applications and in the generation of heat and power for buildings, as part of a decentralised power network. Many deployments will be low power HFCs for domestic combined heat and power (CHP) and commercial ‘transportable’ HFCs for environmental situations, such as lighting and telephone towers. For broad commercialisation of small fuel cells to be achieved there needs to be significant confidence in their safety in both domestic and environmental applications. Low power HFCs are housed in protective steel enclosures. Standard enclosures have plain rectangular ventilation openings intended for thermal management of electronics and not the dispersion of a buoyant gas. Degradation of the HFC or supply pipework in use could lead to a low-level leak and a build-up of hydrogen gas in the enclosure. Hydrogen’s wide flammable range (4-75%) is a significant safety concern, with ineffective enclosure ventilation having the potential to cause flammable mixtures to develop with the risk of explosion. Mechanical ventilation is effective at managing enclosure hydrogen concentrations, but drains HFC power and is vulnerable to failure. This is undesirable in low power and remote installations and reliable passive ventilation systems are preferred. Passive ventilation depends upon buoyancy driven flow, with the size, shape and position of ventilation openings critical for producing predictable flows and maintaining low buoyant gas concentrations. With environmentally sited enclosures, ventilation openings with pressed horizontal and angled louvres are preferred to protect the HFC and electronics inside. There is an economic cost to adding louvres, but also a safety concern. A question arises over whether the use of pressed louvre vents impairs enclosure passive ventilation performance, when compared to same opening area plain vents. Comparison small enclosure (0.144m³) tests of same opening area pressed louvre and plain vents were undertaken. A displacement ventilation arrangement was incorporated into the enclosure with opposing upper and lower ventilation openings. A range of vent areas were tested. Helium (used as a safe analogue for hydrogen) was released from a 4mm nozzle at the base of the enclosure to simulate a hydrogen leak at leak rates from 1 to 10 lpm. Helium sensors were used to record concentrations at eight heights in the enclosure. The enclosure was otherwise empty. These tests determined that the use of pressed and angled louvre ventilation openings on the enclosure impaired the passive ventilation flow and increased helium concentrations in the enclosure. High-level stratified buoyant gas layers were also found to be deeper than with plain vent openings and were within the flammable range. The presence of gas within the flammable range is of concern, particularly as the addition of the fuel cell and electronics in the enclosure would further reduce the available volume and increase concentrations. The opening area of louvre vents would need to be greater than equivalent plain vents to achieve comparable ventilation flows or alternative schemes would need to be considered.Keywords: enclosure, fuel cell, helium, hydrogen safety, louvre vent, passive ventilation
Procedia PDF Downloads 27486 Benefits of Using Social Media and Collaborative Online Platforms in PBL
Authors: Susanna Graziano, Lydia Krstic Ward
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The purpose of this presentation is to demonstrate the steps of using multimedia and collaborative platforms in project-based learning. The presentation will demonstrate the stages of the learning project with various components of independent and collaborative learning, where students research the topic, share information, prepare a survey, use social media (Facebook, Instagram, WhasApp) and collaborative platforms (wikispaces.com and Google docs) to collect, analyze and process data, then produce reports and logos to be displayed as a final product. At the beginning of the presentation participants will answer a questionnaire about project based learning and share their experience on using social media, real–world project work and collaborative learning. Using a PPP, the presentation will walk participants through the steps of a completed project where tertiary education students are involved in putting together a multimedia campaign for safe driving in Kuwait. The research component of the project entails taking a holistic view on the problem of the high death rate in traffic accidents. The final goal of the project is to lead students to raise public awareness about the importance of safe driving. The project steps involve using the social media and collaborative platforms for collecting data and sharing the required materials to be used in the final product – a display of written reports, slogans and videos, as well as oral presentations. The same structure can be used to organize a multimedia campaign focusing on other issues, whilst scaffolding on students’ ability to brainstorm, retrieve information, organize it and engage in collaborative/ cooperative learning whilst being immersed in content-based learning as well as in authentic tasks. More specifically, the project we carried out at Box Hill College was a real-world one and involved a multimedia Campaign for Safe Driving since reckless driving is one of the major problems in the country. The idea for the whole project started by a presentation given by a board member of the Kuwaiti Society for Traffic Safety who was invited to college and spoke about: • Driving laws in the country, • What causes car accidents, • Driving safety tips. The principal goal of this project was to let students consider problems of traffic in Kuwait from different points of view. They also had to address the number and causes of accidents, evaluate the effectiveness of the local traffic law in order to send a warning about the importance of safe driving and, finally, suggest ways of its improvement. Benefits included: • Engagement, • Autonomy, • Motivation, • Content knowledge, • Language mastery, • Enhanced critical thinking, • Increased metacognitive awareness, • Improved social skills, • Authentic experience.Keywords: social media, online learning platforms, collaborative platforms, project based learning
Procedia PDF Downloads 42685 Bank Failures: A Question of Leadership
Authors: Alison L. Miles
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Almost all major financial institutions in the world suffered losses due to the financial crisis of 2007, but the extent varied widely. The causes of the crash of 2007 are well documented and predominately focus on the role and complexity of the financial markets. The dominant theme of the literature suggests the causes of the crash were a combination of globalization, financial sector innovation, moribund regulation and short termism. While these arguments are undoubtedly true, they do not tell the whole story. A key weakness in the current analysis is the lack of consideration of those leading the banks pre and during times of crisis. This purpose of this study is to examine the possible link between the leadership styles and characteristics of the CEO, CFO and chairman and the financial institutions that failed or needed recapitalization. As such, it contributes to the literature and debate on international financial crises and systemic risk and also to the debate on risk management and regulatory reform in the banking sector. In order to first test the proposition (p1) that there are prevalent leadership characteristics or traits in financial institutions, an initial study was conducted using a sample of the top 65 largest global banks and financial institutions according to the Banker Top 1000 banks 2014. Secondary data from publically available and official documents, annual reports, treasury and parliamentary reports together with a selection of press articles and analyst meeting transcripts was collected longitudinally from the period 1998 to 2013. A computer aided key word search was used in order to identify the leadership styles and characteristics of the chairman, CEO and CFO. The results were then compared with the leadership models to form a picture of leadership in the sector during the research period. As this resulted in separate results that needed combining, SPSS data editor was used to aggregate the results across the studies using the variables ‘leadership style’ and ‘company financial performance’ together with the size of the company. In order to test the proposition (p2) that there was a prevalent leadership style in the banks that failed and the proposition (P3) that this was different to those that did not, further quantitative analysis was carried out on the leadership styles of the chair, CEO and CFO of banks that needed recapitalization, were taken over, or required government bail-out assistance during 2007-8. These included: Lehman Bros, Merrill Lynch, Royal Bank of Scotland, HBOS, Barclays, Northern Rock, Fortis and Allied Irish. The findings show that although regulatory reform has been a key mechanism of control of behavior in the banking sector, consideration of the leadership characteristics of those running the board are a key factor. They add weight to the argument that if each crisis is met with the same pattern of popular fury with the financier, increased regulation, followed by back to business as usual, the cycle of failure will always be repeated and show that through a different lens, new paradigms can be formed and future clashes avoided.Keywords: banking, financial crisis, leadership, risk
Procedia PDF Downloads 31884 Memorializing the Holocaust in the Present Century
Authors: Mehak Burza
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As we pause to observe the Holocaust Remembrance Day each year on 27 January, it becomes important to consider how the Holocaust is witnessed, and its education is perceived across the globe. The dissemination of knowledge of the Holocaust becomes more pertinent in the countries that were not directly affected by it. The Holocaust education is not widespread in Asian countries and is thus not mandatory as an academic discipline for school and university students. One such Asian country that often considers Holocaust as an isolated event is India. Though the struggle for freedom began with the 1857 mutiny (the first war of Indian independence) but the freedom revolts gained momentum specifically during the years 1944-1947, when India was steeped in a battery of rebellions. However, freedom for the Indian subcontinent from the domination of British Raj came at the cost of partition of India that resulted in widespread bloodshed and immigration. For India, it is this backdrop of her freedom struggle that always outweighs the incidents of the Second World War, including the catastrophic event of the Holocaust. As a result, the knowledge about the Holocaust is available through secondary sources such as Holocaust documentaries and movies. Besides Anne Frank’s diary, the knowledge about the Holocaust is disseminated through the course readings in the universities. The most common literary acquaintances with the Jewish faith for university students are when they come across the Jewish characters in their course readings. The Prioress’s Tale in Geoffrey Chaucer’s Canterbury Tales, the character of Shylock in William Shakespeare’s The Merchant of Venice, and the Jewish protagonist, Barabas, in Christopher Marlow’s Jew of Malta. Apart from this, the school textbooks mention a detailed chapter on Holocaust and Hitler, which is an encouraging turn. However, there still exists a yawning gap between dissemination and sensitization of Holocaust education owing to different geographical locales. My paper presentation aims to trace the intersectional elements between India and the Holocaust that can serve as the required pivotal stand-board to foster sensitization towards Holocaust education in the Indian subcontinent. For instance, Maharaja Jam SahebDigvijaysinhjiRanjitsinhji, the ruler of Nawanagar, a princely state in British India, helped save thousand Polish Jewish children in 1945 at the time when India herself was steeped in its struggle for freedom. Famously known as the ‘Indian Oskar Schindler’ Polish government has named a street after him in Krakow, Poland. Another example that deserves mention is the spy princess, Noor Inayat Khan, a descendent of Tipu Sultan, who became the most celebrated British spyand fought against the Nazis. Additionally, by offering refuge to Jews, India has proved to be a distant haven for them. Researching further the domain of Jewish refugees in India will not only illuminate a dull/gray zone of investigation but also enable the educators to provide appropriate entry points for introducing the subject of Shoah/Holocaust in India, a subject which unfortunately hitherto is either seldom discussed or is equated with the Partition of India.Keywords: awareness, dissemination, holocaust, India
Procedia PDF Downloads 13983 Robotic Process Automation in Accounting and Finance Processes: An Impact Assessment of Benefits
Authors: Rafał Szmajser, Katarzyna Świetla, Mariusz Andrzejewski
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Robotic process automation (RPA) is a technology of repeatable business processes performed using computer programs, robots that simulate the work of a human being. This approach assumes replacing an existing employee with the use of dedicated software (software robots) to support activities, primarily repeated and uncomplicated, characterized by a low number of exceptions. RPA application is widespread in modern business services, particularly in the areas of Finance, Accounting and Human Resources Management. By utilizing this technology, the effectiveness of operations increases while reducing workload, minimizing possible errors in the process, and as a result, bringing measurable decrease in the cost of providing services. Regardless of how the use of modern information technology is assessed, there are also some doubts as to whether we should replace human activities in the implementation of the automation in business processes. After the initial awe for the new technological concept, a reflection arises: to what extent does the implementation of RPA increase the efficiency of operations or is there a Business Case for implementing it? If the business case is beneficial, in which business processes is the greatest potential for RPA? A closer look at these issues was provided by in this research during which the respondents’ view of the perceived advantages resulting from the use of robotization and automation in financial and accounting processes was verified. As a result of an online survey addressed to over 500 respondents from international companies, 162 complete answers were returned from the most important types of organizations in the modern business services industry, i.e. Business or IT Process Outsourcing (BPO/ITO), Shared Service Centers (SSC), Consulting/Advisory and their customers. Answers were provided by representatives of the positions in their organizations: Members of the Board, Directors, Managers and Experts/Specialists. The structure of the survey allowed the respondents to supplement the survey with additional comments and observations. The results formed the basis for the creation of a business case calculating tangible benefits associated with the implementation of automation in the selected financial processes. The results of the statistical analyses carried out with regard to revenue growth confirmed the correctness of the hypothesis that there is a correlation between job position and the perception of the impact of RPA implementation on individual benefits. Second hypothesis (H2) that: There is a relationship between the kind of company in the business services industry and the reception of the impact of RPA on individual benefits was thus not confirmed. Based results of survey authors performed simulation of business case for implementation of RPA in selected Finance and Accounting Processes. Calculated payback period was diametrically different ranging from 2 months for the Account Payables process with 75% savings and in the extreme case for the process Taxes implementation and maintenance costs exceed the savings resulting from the use of the robot.Keywords: automation, outsourcing, business process automation, process automation, robotic process automation, RPA, RPA business case, RPA benefits
Procedia PDF Downloads 13882 Combustion Variability and Uniqueness in Cylinders of a Radial Aircraft Piston Engine
Authors: Michal Geca, Grzegorz Baranski, Ksenia Siadkowska
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The work is a part of the project which aims at developing innovative power and control systems for the high power aircraft piston engine ASz62IR. Developed electronically controlled ignition system will reduce emissions of toxic compounds as a result of lowered fuel consumption, optimized combustion and engine capability of efficient combustion of ecological fuels. The tested unit is an air-cooled four-stroke gasoline engine of 9 cylinders in a radial setup, mechanically charged by a radial compressor powered by the engine crankshaft. The total engine cubic capac-ity is 29.87 dm3, and the compression ratio is 6.4:1. The maximum take-off power is 1000 HP at 2200 rpm. The maximum fuel consumption is 280 kg/h. Engine powers aircrafts: An-2, M-18 „Dromader”, DHC-3 „OTTER”, DC-3 „Dakota”, GAF-125 „HAWK” i Y5. The main problems of the engine includes the imbalanced work of cylinders. The non-uniformity value in each cylinder results in non-uniformity of their work. In radial engine cylinders arrangement causes that the mixture movement that takes place in accordance (lower cylinder) or the opposite (upper cylinders) to the direction of gravity. Preliminary tests confirmed the presence of uneven workflow of individual cylinders. The phenomenon is most intense at low speed. The non-uniformity is visible on the waveform of cylinder pressure. Therefore two studies were conducted to determine the impact of this phenomenon on the engine performance: simulation and real tests. Simplified simulation was conducted on the element of the intake system coated with fuel film. The study shows that there is an effect of gravity on the movement of the fuel film inside the radial engine intake channels. Both in the lower and the upper inlet channels the film flows downwards. It follows from the fact that gravity assists the movement of the film in the lower cylinder channels and prevents the movement in the upper cylinder channels. Real tests on aircraft engine ASz62IR was conducted in transients condition (rapid change of the excess air in each cylinder were performed. Calculations were conducted for mass of fuel reaching the cylinders theoretically and really and on this basis, the factors of fuel evaporation “x” were determined. Therefore a simplified model of the fuel supply to cylinder was adopted. Model includes time constant of the fuel film τ, the number of engine transport cycles of non-evaporating fuel along the intake pipe γ and time between next cycles Δt. The calculation results of identification of the model parameters are presented in the form of radar graphs. The figures shows the averages declines and increases of the injection time and the average values for both types of stroke. These studies shown, that the change of the position of the cylinder will cause changes in the formation of fuel-air mixture and thus changes in the combustion process. Based on the results of the work of simulation and experiments was possible to develop individual algorithms for ignition control. This work has been financed by the Polish National Centre for Research and Development, INNOLOT, under Grant Agreement No. INNOLOT/I/1/NCBR/2013.Keywords: radial engine, ignition system, non-uniformity, combustion process
Procedia PDF Downloads 36781 Preventing Discharge to No Fixed Address-Youth (NFA-Y)
Authors: Cheryl Forchuk, Sandra Fisman, Steve Cordes, Dan Catunto, Katherine Krakowski, Melissa Jeffrey, John D’Oria
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The discharge of youth aged 16-25 from hospital into homelessness is a prevalent issue despite research indicating social, safety, health and economic detriments on both the individual and community. Lack of stable housing for youth discharged into homelessness results in long-term consequences, including exacerbation of health problems and costly health care service use and hospital readmission. People experiencing homelessness are four times more likely to be readmitted within one month of discharge and hospitals must spend $2,559 more per client. Finding safe housing for these individuals is imperative to their recovery and transition back to the community. People discharged from hospital to homelessness experience challenges, including poor health outcomes and increased hospital readmissions. Youth are the fastest-growing subgroup of people experiencing homelessness in Canada. The needs of youth are unique and include supports related to education, employment opportunities, and age-related service barriers. This study aims to identify the needs of youth at risk of homelessness by evaluating the efficacy of the “Preventing Discharge to No Fixed Address – Youth” (NFA-Y) program, which aims to prevent youth from being discharged from hospital into homelessness. The program connects youth aged 16-25 who are inpatients at London Health Sciences Centre and St. Joseph’s Health Care London to housing and financial support. Supports are offered through collaboration with community partners: Youth Opportunities Unlimited, Canadian Mental Health Association Elgin Middlesex, City of London Coordinated Access, Ontario Works, and Salvation Army’s Housing Stability Bank. This study was reviewed and approved by Western University’s Research Ethics Board. A series of interviews are being conducted with approximately ninety-three youth participants at three time points: baseline (pre-discharge), six, and twelve months post-discharge. Focus groups with participants, health care providers, and community partners are being conducted at three-time points. In addition, administrative data from service providers will be collected and analyzed. Since homelessness has a detrimental effect on recovery, client and community safety, and healthcare expenditure, locating safe housing for psychiatric patients has had a positive impact on treatment, rehabilitation, and the system as a whole. If successful, the findings of this project will offer safe policy alternatives for the prevention of homelessness for at-risk youth, help set them up for success in their future years, and mitigate the rise of the homeless youth population in Canada.Keywords: youth homelessness, no-fixed address, mental health, homelessness prevention, hospital discharge
Procedia PDF Downloads 10580 Experimental Measurement of Equatorial Ring Current Generated by Magnetoplasma Sail in Three-Dimensional Spatial Coordinate
Authors: Masato Koizumi, Yuya Oshio, Ikkoh Funaki
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Magnetoplasma Sail (MPS) is a future spacecraft propulsion that generates high levels of thrust by inducing an artificial magnetosphere to capture and deflect solar wind charged particles in order to transfer momentum to the spacecraft. By injecting plasma in the spacecraft’s magnetic field region, the ring current azimuthally drifts on the equatorial plane about the dipole magnetic field generated by the current flowing through the solenoid attached on board the spacecraft. This ring current results in magnetosphere inflation which improves the thrust performance of MPS spacecraft. In this present study, the ring current was experimentally measured using three Rogowski Current Probes positioned in a circular array about the laboratory model of MPS spacecraft. This investigation aims to determine the detailed structure of ring current through physical experimentation performed under two different magnetic field strengths engendered by varying the applied voltage on the solenoid with 300 V and 600 V. The expected outcome was that the three current probes would detect the same current since all three probes were positioned at equal radial distance of 63 mm from the center of the solenoid. Although experimental results were numerically implausible due to probable procedural error, the trends of the results revealed three pieces of perceptive evidence of the ring current behavior. The first aspect is that the drift direction of the ring current depended on the strength of the applied magnetic field. The second aspect is that the diamagnetic current developed at a radial distance not occupied by the three current probes under the presence of solar wind. The third aspect is that the ring current distribution varied along the circumferential path about the spacecraft’s magnetic field. Although this study yielded experimental evidence that differed from the original hypothesis, the three key findings of this study have informed two critical MPS design solutions that will potentially improve thrust performance. The first design solution is the positioning of the plasma injection point. Based on the implication of the first of the three aspects of ring current behavior, the plasma injection point must be located at a distance instead of at close proximity from the MPS Solenoid for the ring current to drift in the direction that will result in magnetosphere inflation. The second design solution, predicated by the third aspect of ring current behavior, is the symmetrical configuration of plasma injection points. In this study, an asymmetrical configuration of plasma injection points using one plasma source resulted in a non-uniform distribution of ring current along the azimuthal path. This distorts the geometry of the inflated magnetosphere which minimizes the deflection area for the solar wind. Therefore, to realize a ring current that best provides the maximum possible inflated magnetosphere, multiple plasma sources must be spaced evenly apart for the plasma to be injected evenly along its azimuthal path.Keywords: Magnetoplasma Sail, magnetosphere inflation, ring current, spacecraft propulsion
Procedia PDF Downloads 31079 Treatment of Neuronal Defects by Bone Marrow Stem Cells Differentiation to Neuronal Cells Cultured on Gelatin-PLGA Scaffolds Coated with Nano-Particles
Authors: Alireza Shams, Ali Zamanian, Atefehe Shamosi, Farnaz Ghorbani
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Introduction: Although the application of a new strategy remains a remarkable challenge for treatment of disabilities due to neuronal defects, progress in Nanomedicine and tissue engineering, suggesting the new medical methods. One of the promising strategies for reconstruction and regeneration of nervous tissue is replacing of lost or damaged cells by specific scaffolds after Compressive, ischemic and traumatic injuries of central nervous system. Furthermore, ultrastructure, composition, and arrangement of tissue scaffolds are effective on cell grafts. We followed implantation and differentiation of mesenchyme stem cells to neural cells on Gelatin Polylactic-co-glycolic acid (PLGA) scaffolds coated with iron nanoparticles. The aim of this study was to evaluate the capability of stem cells to differentiate into motor neuron-like cells under topographical cues and morphogenic factors. Methods and Materials: Bone marrow mesenchymal stem cells (BMMSCs) was obtained by primary cell culturing of adult rat bone marrow got from femur bone by flushing method. BMMSCs were incubated with DMEM/F12 (Gibco), 15% FBS and 100 U/ml pen/strep as media. Then, BMMSCs seeded on Gel/PLGA scaffolds and tissue culture (TCP) polystyrene embedded and incorporated by Fe Nano particles (FeNPs) (Fe3o4 oxide (M w= 270.30 gr/mol.). For neuronal differentiation, 2×10 5 BMMSCs were seeded on Gel/PLGA/FeNPs scaffolds was cultured for 7 days and 0.5 µ mol. Retinoic acid, 100 µ mol. Ascorbic acid,10 ng/ml. Basic fibroblast growth factor (Sigma, USA), 250 μM Iso butyl methyl xanthine, 100 μM 2-mercaptoethanol, and 0.2 % B27 (Invitrogen, USA) added to media. Proliferation of BMMSCs was assessed by using MTT assay for cell survival. The morphology of BMMSCs and scaffolds was investigated by scanning electron microscopy analysis. Expression of neuron-specific markers was studied by immunohistochemistry method. Data were analyzed by analysis of variance, and statistical significance was determined by Turkey’s test. Results: Our results revealed that differentiation and survival of BMMSCs into motor neuron-like cells on Gel/PLGA/FeNPs as a biocompatible and biodegradable scaffolds were better than those cultured in Gel/PLGA in absence of FeNPs and TCP scaffolds. FeNPs had raised physical power but decreased capacity absorption of scaffolds. Well defined oriented pores in scaffolds due to FeNPs may activate differentiation and synchronized cells as a mechanoreceptor. Induction effects of magnetic FeNPs by One way flow of channels in scaffolds help to lead the cells and can facilitate direction of their growth processes. Discussion: Progression of biological properties of BMMSCs and the effects of FeNPs spreading under magnetic field was evaluated in this investigation. In vitro study showed that the Gel/PLGA/FeNPs scaffold provided a suitable structure for motor neuron-like cells differentiation. This could be a promising candidate for enhancing repair and regeneration in neural defects. Dynamic and static magnetic field for inducing and construction of cells can provide better results for further experimental studies.Keywords: differentiation, mesenchymal stem cells, nano particles, neuronal defects, Scaffolds
Procedia PDF Downloads 16678 Analyzing the Heat Transfer Mechanism in a Tube Bundle Air-PCM Heat Exchanger: An Empirical Study
Authors: Maria De Los Angeles Ortega, Denis Bruneau, Patrick Sebastian, Jean-Pierre Nadeau, Alain Sommier, Saed Raji
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Phase change materials (PCM) present attractive features that made them a passive solution for thermal comfort assessment in buildings during summer time. They show a large storage capacity per volume unit in comparison with other structural materials like bricks or concrete. If their use is matched with the peak load periods, they can contribute to the reduction of the primary energy consumption related to cooling applications. Despite these promising characteristics, they present some drawbacks. Commercial PCMs, as paraffines, offer a low thermal conductivity affecting the overall performance of the system. In some cases, the material can be enhanced, adding other elements that improve the conductivity, but in general, a design of the unit that optimizes the thermal performance is sought. The material selection is the departing point during the designing stage, and it does not leave plenty of room for optimization. The PCM melting point depends highly on the atmospheric characteristics of the building location. The selection must relay within the maximum, and the minimum temperature reached during the day. The geometry of the PCM container and the geometrical distribution of these containers are designing parameters, as well. They significantly affect the heat transfer, and therefore its phenomena must be studied exhaustively. During its lifetime, an air-PCM unit in a building must cool down the place during daytime, while the melting of the PCM occurs. At night, the PCM must be regenerated to be ready for next uses. When the system is not in service, a minimal amount of thermal exchanges is desired. The aforementioned functions result in the presence of sensible and latent heat storage and release. Hence different types of mechanisms drive the heat transfer phenomena. An experimental test was designed to study the heat transfer phenomena occurring in a circular tube bundle air-PCM exchanger. An in-line arrangement was selected as the geometrical distribution of the containers. With the aim of visual identification, the containers material and a section of the test bench were transparent. Some instruments were placed on the bench for measuring temperature and velocity. The PCM properties were also available through differential scanning calorimeter (DSC) tests. An evolution of the temperature during both cycles, melting and solidification were obtained. The results showed some phenomena at a local level (tubes) and on an overall level (exchanger). Conduction and convection appeared as the main heat transfer mechanisms. From these results, two approaches to analyze the heat transfer were followed. The first approach described the phenomena in a single tube as a series of thermal resistances, where a pure conduction controlled heat transfer was assumed in the PCM. For the second approach, the temperature measurements were used to find some significant dimensionless numbers and parameters as Stefan, Fourier and Rayleigh numbers, and the melting fraction. These approaches allowed us to identify the heat transfer phenomena during both cycles. The presence of natural convection during melting might have been stated from the influence of the Rayleigh number on the correlations obtained.Keywords: phase change materials, air-PCM exchangers, convection, conduction
Procedia PDF Downloads 18077 Cognitive Mechanisms of Mindfulness-Based Cognitive Therapy on Depressed Older Adults: The Mediating Role of Rumination and Autobiographical Memory Specificity
Authors: Wai Yan Shih, Sau Man Wong, Wing Chung Chang, Wai Chi Chan
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Background: Late-life depression is associated with significant consequences. Although symptomatic reduction is achievable through pharmacological interventions, older adults are more vulnerable to the side effects than their younger counterparts. In addition, drugs do not address underlying cognitive dysfunctions such as rumination and reduced autobiographical memory specificity (AMS), both shown to be maladaptive coping styles that are associated with a poorer prognosis in depression. Considering how aging is accompanied by cognitive, psychological and physical changes, the interplay of these age-related factors may potentially aggravate and interfere with these depressive cognitive dysfunctions in late-life depression. Special care should, therefore, be drawn to ensure these cognitive dysfunctions are adequately addressed. Aim: This randomized controlled trial aims to examine the effect of mindfulness-based cognitive therapy (MBCT) on depressed older adults, and whether the potential benefits of MBCT are mediated by improvements in rumination and AMS. Method: Fifty-seven participants with an average age of 70 years old were recruited from multiple elderly centers and online mailing lists. Participants were assessed with: (1) Hamilton depression scale, (2) ruminative response scale, (3) autobiographical memory test, (4) mindful attention awareness scale, and (5) Montreal cognitive assessment. Eligible participants with mild to moderate depressive symptoms and normal cognitive functioning were randomly allocated to an 8-week MBCT group or active control group consisting of a low-intensity exercise program and health education. Post-intervention assessments were conducted after the 8-week program. Ethics approval was given by the Institutional Review Board of the University of Hong Kong/Hospital Authority. Results: Mixed-factorials ANOVAs demonstrated significant time x group interaction effects for depressive symptoms, AMS, and dispositional mindfulness. A marginally significant interaction effect was found for rumination. Simple effect analyses revealed a significant reduction in depressive symptoms for the both the MBCT group (mean difference = 7.1, p = .000), and control group (mean difference = 2.7, p = .023). However, only participants in the MBCT group demonstrated improvements in rumination, AMS, and dispositional mindfulness. Bootstrapping-based mediation analyses showed that the effect of MBCT in alleviating depressive symptoms was only mediated by the reduction in rumination. Conclusions: The findings support the use of MBCT as an effective intervention for depressed older adults, considering the improvements in depressive symptoms, rumination, AMS and dispositional mindfulness despite their age. Reduction in ruminative tendencies plays a major role in the cognitive mechanism of MBCT.Keywords: mindfulness-based cognitive therapy, depression, older adults, rumination, autobiographical memory specificity
Procedia PDF Downloads 21176 Journeys of Healing for Military Veterans: A Pilot Study
Authors: Heather Warfield, Brad Genereux
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Military personnel encounter a number of challenges when separating from military service to include career uncertainty, relational/family dynamics, trauma as a result of military experiences, reconceptualization of identity, and existential issues related to purpose, meaning making and framing of the military experience(s). Embedded within military culture are well-defined rites of passage and a significant sense of belonging. Consequently, transition out of the military can result in the loss of such rites of passage and belongingness. However, a pilgrimage journey can provide the time and space to engage in a new rite of passage, to construct a new pilgrim identity, and a to develop deep social relationships that lead to a sense of belongingness to a particular pilgrim community as well as to the global community of pilgrims across numerous types of pilgrimage journeys. The aims of the current paper are to demonstrate the rationale for why pilgrimage journeys are particularly significant for military veterans, provide an overview of an innovative program that facilitates the Camino de Santiago pilgrimage for military veterans, and discusses the lessons learned from the initial pilot project of a recently established program. Veterans on the Camino (VOC) is an emerging nongovernmental organization in the USA. Founded by a military veteran, after leaving his military career, the primary objective of the organization is to facilitate healing for veterans via the Camino de Santiago pilgrimage journey. As part of the program, participants complete a semi-structured interview at three time points – pre, during, and post journey. The interview items are based on ongoing research by the principal investigator and address such constructs as meaning-making, wellbeing, therapeutic benefits and transformation. In addition, program participants complete The Sources of Meaning and Meaning in Life Questionnaire (SoMe). The pilot program occurred in the spring of 2017. Five participants were selected after an extensive application process and review by a three-person selection board. The selection criteria included demonstrated compatibility with the program objectives (i.e., prior military experience, availability for a 40 day journey, and awareness of the need for a transformational intervention). The participants were connected as a group through a private Facebook site and interacted with one another for several months prior to the pilgrimage. Additionally, the participants were interviewed prior to beginning the pilgrimage, at one point during the pilgrimage and immediately following the conclusion of the pilgrimage journey. The interviews yielded themes related to loss, meaning construction, renewed hope in humanity, and a commitment to future goals. The lessons learned from this pilot project included a confirmation of the need for such a program, a need for greater focus on logistical details, and the recognition that the pilgrimage experience needs to continue in some manner once the veterans return home.Keywords: pilgrimage, healing, military veterans, Camino de Santiago
Procedia PDF Downloads 28975 A Qualitative Study to Analyze Clinical Coders’ Decision Making Process of Adverse Drug Event Admissions
Authors: Nisa Mohan
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Clinical coding is a feasible method for estimating the national prevalence of adverse drug event (ADE) admissions. However, under-coding of ADE admissions is a limitation of this method. Whilst the under-coding will impact the accurate estimation of the actual burden of ADEs, the feasibility of the coded data in estimating the adverse drug event admissions goes much further compared to the other methods. Therefore, it is necessary to know the reasons for the under-coding in order to improve the clinical coding of ADE admissions. The ability to identify the reasons for the under-coding of ADE admissions rests on understanding the decision-making process of coding ADE admissions. Hence, the current study aimed to explore the decision-making process of clinical coders when coding cases of ADE admissions. Clinical coders from different levels of coding job such as trainee, intermediate and advanced level coders were purposefully selected for the interviews. Thirteen clinical coders were recruited from two Auckland region District Health Board hospitals for the interview study. Semi-structured, one-on-one, face-to-face interviews using open-ended questions were conducted with the selected clinical coders. Interviews were about 20 to 30 minutes long and were audio-recorded with the approval of the participants. The interview data were analysed using a general inductive approach. The interviews with the clinical coders revealed that the coders have targets to meet, and they sometimes hesitate to adhere to the coding standards. Coders deviate from the standard coding processes to make a decision. Coders avoid contacting the doctors for clarifying small doubts such as ADEs and the name of the medications because of the delay in getting a reply from the doctors. They prefer to do some research themselves or take help from their seniors and colleagues for making a decision because they can avoid a long wait to get a reply from the doctors. Coders think of ADE as a small thing. Lack of time for searching for information to confirm an ADE admission, inadequate communication with clinicians, along with coders’ belief that an ADE is a small thing may contribute to the under-coding of the ADE admissions. These findings suggest that further work is needed on interventions to improve the clinical coding of ADE admissions. Providing education to coders about the importance of ADEs, educating clinicians about the importance of clear and confirmed medical records entries, availing pharmacists’ services to improve the detection and clear documentation of ADE admissions, and including a mandatory field in the discharge summary about external causes of diseases may be useful for improving the clinical coding of ADE admissions. The findings of the research will help the policymakers to make informed decisions about the improvements. This study urges the coding policymakers, auditors, and trainers to engage with the unconscious cognitive biases and short-cuts of the clinical coders. This country-specific research conducted in New Zealand may also benefit other countries by providing insight into the clinical coding of ADE admissions and will offer guidance about where to focus changes and improvement initiatives.Keywords: adverse drug events, clinical coders, decision making, hospital admissions
Procedia PDF Downloads 12074 Common Used Non-Medical Practice and Perceived Benefits in Couples with Fertility Problems in Turkey
Authors: S. Fata, M. A. Tokat, N. Bagardi, B. Yilmaz
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Nowadays, various traditional practices are used throughout the world with aim to improve fertility. Various traditional remedies, acupuncture, religious practices such as sacrifice are frequently used. Studies often evaluate the traditional practices used by the women. But the use of this non-medical practice by couples and specific application reasons of this methods has been less investigated. The aim of this study was to evaluate the common used non-medical practices and determine perceived benefits by couples with fertility problems in Turkey. This is a descriptive study. Research data were collected between May-July 2016, in Izmir Ege Birth Education and Research Hospital Assisted Reproduction Clinic, from 151 couples with fertility problem. Personal Information Form and Non-Medical Practices Used for Fertility Evaluation Form was used. Number 'GOA 2649' permission letter from Dokuz Eylul University Non-Invasive Research Ethics Board, permission letter from the institution and the written consent from participants has been received to carry out the study. In the evaluation of the data, frequencies and proportions analysis were used. The average age of women participating in the study was 32.87, the 35.8% were high school graduates, 60.3% were housewife and the 58.9% lived in city. The 30.5% of husbands were high school graduates, the 96.7% were employed and the 60.9% lived in city. The 78.1% of couples lived as a nuclear family, the average marriage year was 7.58, in 33.8% the fertility problem stems from women, 42.4% of them received a diagnosis for 1-2 years, 35.1% were being treated for 1-2 years. The 35.8% of women reported use of non-medical applications. The 24.4% of women used figs, onion cure, hacemat, locust, bee-pollen milk, the 18.2% used herbs, the 13.1% vowed, the 12.1% went to the tomb, the 10.1% did not bath a few days after the embryo transfer, the 9.1% used thermal water baths, the 5.0% manually corrected the womb, the 5.0% printed amulets by Hodja, the 3.0% went to the Hodja/pilgrims. Among the perceived benefits of using non-medical practices; facilitate pregnancy and implantation, improve oocyte quality were the most recently expressed. Women said that they often used herbs to develop follicles, did not bath after embryo transfer with aim to provide implantation, and used thermal waters to get rid of the infection. Compared to women, only the 25.8% of men used the non-medical practice. The 52.1% reported that they used peanuts, hacemat, locust, bee-pollen milk, the 14.9% used herbs, the 12.8% vowed, the 10.1% went to the tomb, the 10.1% used thermal water baths. Improve sperm number, motility and quality were the most expected benefits. Men said that they often used herbs to improve sperm number, used peanuts, hacemat, locust, bee-pollen milk to improve sperm motility and quality. Couples in Turkey often use non-medical practices to deal with fertility problems. Some of the practices considered as useful can adversely affect health. Healthcare providers should evaluate the use of non-medical practices and should inform if the application is known adverse effects on health.Keywords: fertility, couples, non-medical practice, perceived benefit
Procedia PDF Downloads 34273 Combining Patients Pain Scores Reports with Functionality Scales in Chronic Low Back Pain Patients
Authors: Ivana Knezevic, Kenneth D. Candido, N. Nick Knezevic
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Background: While pain intensity scales remain generally accepted assessment tool, and the numeric pain rating score is highly subjective, we nevertheless rely on them to make a judgment about treatment effects. Misinterpretation of pain can lead practitioners to underestimate or overestimate the patient’s medical condition. The purpose of this study was to analyze how the numeric rating pain scores given by patients with low back pain correlate with their functional activity levels. Methods: We included 100 consecutive patients with radicular low back pain (LBP) after the Institutional Review Board (IRB) approval. Pain scores, numeric rating scale (NRS) responses at rest and in the movement,Oswestry Disability Index (ODI) questionnaire answers were collected 10 times through 12 months. The ODI questionnaire is targeting a patient’s activities and physical limitations as well as a patient’s ability to manage stationary everyday duties. Statistical analysis was performed by using SPSS Software version 20. Results: The average duration of LBP was 14±22 months at the beginning of the study. All patients included in the study were between 24 and 78 years old (average 48.85±14); 56% women and 44% men. Differences between ODI and pain scores in the range from -10% to +10% were considered “normal”. Discrepancies in pain scores were graded as mild between -30% and -11% or +11% and +30%; moderate between -50% and -31% and +31% and +50% and severe if differences were more than -50% or +50%. Our data showed that pain scores at rest correlate well with ODI in 65% of patients. In 30% of patients mild discrepancies were present (negative in 21% and positive in 9%), 4% of patients had moderate and 1% severe discrepancies. “Negative discrepancy” means that patients graded their pain scores much higher than their functional ability, and most likely exaggerated their pain. “Positive discrepancy” means that patients graded their pain scores much lower than their functional ability, and most likely underrated their pain. Comparisons between ODI and pain scores during movement showed normal correlation in only 39% of patients. Mild discrepancies were present in 42% (negative in 39% and positive in 3%); moderate in 14% (all negative), and severe in 5% (all negative) of patients. A 58% unknowingly exaggerated their pain during movement. Inconsistencies were equal in male and female patients (p=0.606 and p=0.928).Our results showed that there was a negative correlation between patients’ satisfaction and the degree of reporting pain inconsistency. Furthermore, patients talking opioids showed more discrepancies in reporting pain intensity scores than did patients taking non-opioid analgesics or not taking medications for LBP (p=0.038). There was a highly statistically significant correlation between morphine equivalents doses and the level of discrepancy (p<0.0001). Conclusion: We have put emphasis on the patient education in pain evaluation as a vital step in accurate pain level reporting. We have showed a direct correlation with patients’ satisfaction. Furthermore, we must identify other parameters in defining our patients’ chronic pain conditions, such as functionality scales, quality of life questionnaires, etc., and should move away from an overly simplistic subjective rating scale.Keywords: pain score, functionality scales, low back pain, lumbar
Procedia PDF Downloads 23572 Evaluation of Requests and Outcomes of Magnetic Resonance Imaging Assessing for Cauda Equina Syndrome at a UK Trauma Centre
Authors: Chris Cadman, Marcel Strauss
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Background: In 2020, the University Hospital Wishaw in the United Kingdom became the centre for trauma and orthopaedics within its health board. This resulted in the majority of patients with suspected cauda equina syndrome (CES) being assessed and imaged at this site, putting an increased demand on MR imaging and displacing other previous activity. Following this transition, imaging requests for CES did not always follow national guidelines and would often be missing important clinical and safety information. There also appeared to be a very low positive scan rate compared with previously reported studies. In an attempt to improve patient selection and reduce the burden of CES imaging at this site clinical audit was performed. Methods: A total of 250 consecutive patients imaged to assess for CES were evaluated. Patients had to have presented to either the emergency or orthopaedic department acutely with a presenting complaint of suspected CES. Patients were excluded if they were not admitted acutely or were assessed by other clinical specialities. In total, 233 patients were included. Requests were assessed for appropriate clinical history, accurate and complete clinical assessment and MRI safety information. Clinical assessment was allocated a score of 1-6 based on information relating to history of pain, level of pain, dermatomes/myotomes affected, peri-anal paraesthesia/anaesthesia, anal tone and post-void bladder volume with each element scoring one point. Images were assessed for positive findings of CES, acquired spinal stenosis or nerve root compression. Results: Overall, 73% of requests had a clear clinical history of CES. The urgency of the request for imaging was given in 23% of cases. The mean clinical assessment score was 3.7 out of a total of 6. Overall, 2% of scans were positive for CES, 29% had acquired spinal stenosis and 30% had nerve root compression. For patients with CES, 75% had acute neurological signs compared with 68% of the study population. CES patients had a mean clinical history score of 5.3 compared with 3.7 for the study population. Overall, 95% of requests had appropriate MRI safety information. Discussion: it study included 233 patients who underwent specialist assessment and referral for MR imaging for suspected CES. Despite the serious nature of this condition, a large proportion of imaging requests did not have a clear clinical query of CES and the level of urgency was not given, which could potentially lead to a delay in imaging and treatment. Clinical examination was often also incomplete, which can make triaging of patients presenting with similar symptoms challenging. The positive rate for CES was only 2%, much below other studies which had positive rates of 6–40% with a large meta-analysis finding a mean positive rate of 19%. These findings demonstrate an opportunity to improve the quality of imaging requests for suspected CES. This may help to improve patient selection for imaging and result in a positive rate for CES imaging that is more in line with other centres.Keywords: cauda equina syndrome, acute back pain, MRI, spine
Procedia PDF Downloads 1571 Assessment of Taiwan Railway Occurrences Investigations Using Causal Factor Analysis System and Bayesian Network Modeling Method
Authors: Lee Yan Nian
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Safety investigation is different from an administrative investigation in that the former is conducted by an independent agency and the purpose of such investigation is to prevent accidents in the future and not to apportion blame or determine liability. Before October 2018, Taiwan railway occurrences were investigated by local supervisory authority. Characteristics of this kind of investigation are that enforcement actions, such as administrative penalty, are usually imposed on those persons or units involved in occurrence. On October 21, 2018, due to a Taiwan Railway accident, which caused 18 fatalities and injured another 267, establishing an agency to independently investigate this catastrophic railway accident was quickly decided. The Taiwan Transportation Safety Board (TTSB) was then established on August 1, 2019 to take charge of investigating major aviation, marine, railway and highway occurrences. The objective of this study is to assess the effectiveness of safety investigations conducted by the TTSB. In this study, the major railway occurrence investigation reports published by the TTSB are used for modeling and analysis. According to the classification of railway occurrences investigated by the TTSB, accident types of Taiwan railway occurrences can be categorized into: derailment, fire, Signal Passed at Danger and others. A Causal Factor Analysis System (CFAS) developed by the TTSB is used to identify the influencing causal factors and their causal relationships in the investigation reports. All terminologies used in the CFAS are equivalent to the Human Factors Analysis and Classification System (HFACS) terminologies, except for “Technical Events” which was added to classify causal factors resulting from mechanical failure. Accordingly, the Bayesian network structure of each occurrence category is established based on the identified causal factors in the CFAS. In the Bayesian networks, the prior probabilities of identified causal factors are obtained from the number of times in the investigation reports. Conditional Probability Table of each parent node is determined from domain experts’ experience and judgement. The resulting networks are quantitatively assessed under different scenarios to evaluate their forward predictions and backward diagnostic capabilities. Finally, the established Bayesian network of derailment is assessed using investigation reports of the same accident which was investigated by the TTSB and the local supervisory authority respectively. Based on the assessment results, findings of the administrative investigation is more closely tied to errors of front line personnel than to organizational related factors. Safety investigation can identify not only unsafe acts of individual but also in-depth causal factors of organizational influences. The results show that the proposed methodology can identify differences between safety investigation and administrative investigation. Therefore, effective intervention strategies in associated areas can be better addressed for safety improvement and future accident prevention through safety investigation.Keywords: administrative investigation, bayesian network, causal factor analysis system, safety investigation
Procedia PDF Downloads 12570 Graphene-Graphene Oxide Dopping Effect on the Mechanical Properties of Polyamide Composites
Authors: Daniel Sava, Dragos Gudovan, Iulia Alexandra Gudovan, Ioana Ardelean, Maria Sonmez, Denisa Ficai, Laurentia Alexandrescu, Ecaterina Andronescu
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Graphene and graphene oxide have been intensively studied due to the very good properties, which are intrinsic to the material or come from the easy doping of those with other functional groups. Graphene and graphene oxide have known a broad band of useful applications, in electronic devices, drug delivery systems, medical devices, sensors and opto-electronics, coating materials, sorbents of different agents for environmental applications, etc. The board range of applications does not come only from the use of graphene or graphene oxide alone, or by its prior functionalization with different moieties, but also it is a building block and an important component in many composite devices, its addition coming with new functionalities on the final composite or strengthening the ones that are already existent on the parent product. An attempt to improve the mechanical properties of polyamide elastomers by compounding with graphene oxide in the parent polymer composition was attempted. The addition of the graphene oxide contributes to the properties of the final product, improving the hardness and aging resistance. Graphene oxide has a lower hardness and textile strength, and if the amount of graphene oxide in the final product is not correctly estimated, it can lead to mechanical properties which are comparable to the starting material or even worse, the graphene oxide agglomerates becoming a tearing point in the final material if the amount added is too high (in a value greater than 3% towards the parent material measured in mass percentages). Two different types of tests were done on the obtained materials, the hardness standard test and the tensile strength standard test, and they were made on the obtained materials before and after the aging process. For the aging process, an accelerated aging was used in order to simulate the effect of natural aging over a long period of time. The accelerated aging was made in extreme heat. For all materials, FT-IR spectra were recorded using FT-IR spectroscopy. From the FT-IR spectra only the bands corresponding to the polyamide were intense, while the characteristic bands for graphene oxide were very small in comparison due to the very small amounts introduced in the final composite along with the low absorptivity of the graphene backbone and limited number of functional groups. In conclusion, some compositions showed very promising results, both in tensile strength test and in hardness tests. The best ratio of graphene to elastomer was between 0.6 and 0.8%, this addition extending the life of the product. Acknowledgements: The present work was possible due to the EU-funding grant POSCCE-A2O2.2.1-2013-1, Project No. 638/12.03.2014, code SMIS-CSNR 48652. The financial contribution received from the national project ‘New nanostructured polymeric composites for centre pivot liners, centre plate and other components for the railway industry (RONERANANOSTRUCT)’, No: 18 PTE (PN-III-P2-2.1-PTE-2016-0146) is also acknowledged.Keywords: graphene, graphene oxide, mechanical properties, dopping effect
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