Search results for: client interaction
1667 Simulation Study of Enhanced Terahertz Radiation Generation by Two-Color Laser Plasma Interaction
Authors: Nirmal Kumar Verma, Pallavi Jha
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Terahertz (THz) radiation generation by propagation of two-color laser pulses in plasma is an active area of research due to its potential applications in various areas, including security screening, material characterization and spectroscopic techniques. Due to non ionizing nature and the ability to penetrate several millimeters, THz radiation is suitable for diagnosis of cancerous cells. Traditional THz emitters like optically active crystals when irradiated with high power laser radiation, are subject to material breakdown and hence low conversion efficiencies. This problem is not encountered in laser - plasma based THz radiation sources. The present paper is devoted to the simulation study of the enhanced THz radiation generation by propagation of two-color, linearly polarized laser pulses through magnetized plasma. The two laser pulses orthogonally polarized are co-propagating along the same direction. The direction of the external magnetic field is such that one of the two laser pulses propagates in the ordinary mode, while the other pulse propagates in the extraordinary mode through homogeneous plasma. A transverse electromagnetic wave with frequency in the THz range is generated due to the presence of the static magnetic field. It is observed that larger amplitude terahertz can be generated by mixing of ordinary and extraordinary modes of two-color laser pulses as compared with a single laser pulse propagating in the extraordinary mode.Keywords: two-color laser pulses, terahertz radiation, magnetized plasma, ordinary and extraordinary mode
Procedia PDF Downloads 3021666 Numerical Simulation of Unsteady Cases of Fluid Flow Using Modified Dynamic Boundary Condition (mDBC) in Smoothed Particle Hydrodynamics Models
Authors: Exa Heydemans, Jessica Sjah, Dwinanti Rika Marthanty
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This paper presents numerical simulations using an open boundary algorithm with modified dynamic boundary condition (mDBC) for weakly compressible smoothed particle hydrodynamics models from particle-based code Dualsphysics. The problems of piping erosion in dams and dikes are aimed for studying the algorithm. The case 2D model of unsteady fluid flow past around a fixed cylinder is simulated, where various values of Reynold’s numbers (Re40, Re60, Re80, and Re100) and different model’s resolution are considered. A constant velocity with different values of viscosity for generating various Reynold’s numbers and different numbers of particles over a cylinder for the resolution are modeled. The interaction between solid particles of the cylinder and fluid particles is concerned. The cylinder is affected by the hydrodynamics force caused by the flow of fluid particles. The solid particles of the cylinder are the observation points to obtain force and pressure due to the hydrodynamics forces. As results of the simulation, which is to show the capability to model 2D unsteady with various Reynold’s numbers, the pressure coefficient, drag coefficient, lift coefficient, and Strouhal number are compared to the previous work from literature.Keywords: hydrodynamics, internal erosion, dualsphysics, viscous fluid flow
Procedia PDF Downloads 1651665 Flame Volume Prediction and Validation for Lean Blowout of Gas Turbine Combustor
Authors: Ejaz Ahmed, Huang Yong
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The operation of aero engines has a critical importance in the vicinity of lean blowout (LBO) limits. Lefebvre’s model of LBO based on empirical correlation has been extended to flame volume concept by the authors. The flame volume takes into account the effects of geometric configuration, the complex spatial interaction of mixing, turbulence, heat transfer and combustion processes inside the gas turbine combustion chamber. For these reasons, flame volume based LBO predictions are more accurate. Although LBO prediction accuracy has improved, it poses a challenge associated with Vf estimation in real gas turbine combustors. This work extends the approach of flame volume prediction previously based on fuel iterative approximation with cold flow simulations to reactive flow simulations. Flame volume for 11 combustor configurations has been simulated and validated against experimental data. To make prediction methodology robust as required in the preliminary design stage, reactive flow simulations were carried out with the combination of probability density function (PDF) and discrete phase model (DPM) in FLUENT 15.0. The criterion for flame identification was defined. Two important parameters i.e. critical injection diameter (Dp,crit) and critical temperature (Tcrit) were identified, and their influence on reactive flow simulation was studied for Vf estimation. Obtained results exhibit ±15% error in Vf estimation with experimental data.Keywords: CFD, combustion, gas turbine combustor, lean blowout
Procedia PDF Downloads 2681664 An Improved Multiple Scattering Reflectance Model Based on Specular V-Cavity
Authors: Hongbin Yang, Mingxue Liao, Changwen Zheng, Mengyao Kong, Chaohui Liu
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Microfacet-based reflection models are widely used to model light reflections for rough surfaces. Microfacet models have become the standard surface material building block for describing specular components with varying roughness; and yet, while they possess many desirable properties as well as produce convincing results, their design ignores important sources of scattering, which can cause a significant loss of energy. Specifically, they only simulate the single scattering on the microfacets and ignore the subsequent interactions. As the roughness increases, the interaction will become more and more important. So a multiple-scattering microfacet model based on specular V-cavity is presented for this important open problem. However, it spends much unnecessary rendering time because of setting the same number of scatterings for different roughness surfaces. In this paper, we design a geometric attenuation term G to compute the BRDF (Bidirectional reflection distribution function) of multiple scattering of rough surfaces. Moreover, we consider determining the number of scattering by deterministic heuristics for different roughness surfaces. As a result, our model produces a similar appearance of the objects with the state of the art model with significantly improved rendering efficiency. Finally, we derive a multiple scattering BRDF based on the original microfacet framework.Keywords: bidirectional reflection distribution function, BRDF, geometric attenuation term, multiple scattering, V-cavity model
Procedia PDF Downloads 1161663 Effect of Salicylic Acid and Nitrogen Fertilizer on Wheat Growth and Yield
Authors: Omar Ibrahim, Aly A. Gaafar, K. A. Ratib
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Two field experiments in micro plots were carried out during the winter seasons of 2012/2013 and 2013/2014, Soil Salinity Laboratory, Alexandria, Egypt, to study the effect of three levels of salicylic acid (SA) as a growth regulator (0, 50, 100 ppm) and three rates of nitrogen fertilizer (75, 100, 125 kg N/feddan) on growth and yield of a spring wheat (Giza 168). The experimental design was a split plot with the main plots in randomized complete block design (RCBD) and four replicates. The results indicated that increasing nitrogen fertilizer rates resulted in insignificant effect on both plant height (cm) and grain weight/spike only. However, a significant effect was observed in all the other studied characters due to the increase in nitrogen fertilizer. On the other hand, increasing salicylic acid rates resulted in insignificant effect in all the studied characters except for chlorophyll a, chlorophyll b, number of grain/spike, and grain yield (gm/ plot). The highest effects on grain yield in wheat were obtained by the rate of 125 kg/feddan of nitrogen fertilizer and 100 ppm of salicylic acid. In conclusion, the data indicated that a high grain yield could be obtained by adding 100 kg/feddan of nitrogen fertilizer and spraying of 50 ppm of salicylic acid with no significant difference with the highest rates. Finally, the interaction had no significant effect on all the studied characters.Keywords: growth regulator, nitrogen fertilizer, spring wheat, salicylic acid
Procedia PDF Downloads 1171662 Application of Synthetic Monomers Grafted Xanthan Gum for Rhodamine B Removal in Aqueous Solution
Authors: T. Moremedi, L. Katata-Seru, S. Sardar, A. Bandyopadhyay, E. Makhado, M. Joseph Hato
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The rapid industrialisation and population growth have led to a steady fall in freshwater supplies worldwide. As a result, water systems are affected by modern methods upon use due to secondary contamination. The application of novel adsorbents derived from natural polymer holds a great promise in addressing challenges in water treatment. In this study, the UV irradiation technique was used to prepare acrylamide (AAm) monomer, and acrylic acid (AA) monomer grafted xanthan gum (XG) copolymer. Furthermore, the factors affecting rhodamine B (RhB) adsorption from aqueous media, such as pH, dosage, concentration, and time were also investigated. The FTIR results confirmed the formation of graft copolymer by the strong vibrational bands at 1709 cm-1 and 1612 cm-1 for AA and AAm, respectively. Additionally, more irregular, porous and wrinkled surface observed from SEM of XG-g-AAm/AA indicated copolymerization interaction of monomers. The optimum conditions for removing RhB dye with a maximum adsorption capacity of 313 mg/g at 25 0C from aqueous solution were pH approximately 5, initial dye concentration = 200 ppm, adsorbent dose = 30 mg. Also, the detailed investigation of the isothermal and adsorption kinetics of RhB from aqueous solution showed that the adsorption of the dye followed a Freundlich model (R2 = 0.96333) and pseudo-second-order kinetics. The results further indicated that this absorbent based on XG had the universality to remove dye through the mechanism of chemical adsorption. The outstanding adsorption potential of the grafted copolymer could be used to remove cationic dyes from aqueous solution as a low-cost product.Keywords: xanthan gum, adsorbents, rhodamine B, Freundlich
Procedia PDF Downloads 1271661 Synthesis, Structural, Magnetic, Optical, and Dielectric Characterization of Nickel-Substituted Cobalt Ferrite Nanoparticles and Potential Antibacterial Applications
Authors: Tesfay Gebremicheal Reda, K. Samatha, Paul Douglas Sanasi, D. Parajuli
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Nanoparticle technology is fast progressing and is being employed in innumerable medical applications. At this time, the public's health is seriously threatened by the rise of bacterial strains resistant to several medications. Metal nanoparticles are a potential alternate approach for tackling this global concern, and this is the main focus of this study. The citrate precursor sol-gel synthesis method was used to synthesize the Niₓ Co₁₋ₓ Fe₂ O₄, (where x = 0.0:0.2:1.0) nanoparticle. XRD identified the development of the cubic crystal structure to have a preferential orientation along (311), and the average particle size was found to be 29-38 nm. The average crystallizes assessed with ImageJ software and origin 22 of the SEM are nearly identical to the XRD results. In the created NCF NPs, the FT-IR spectroscopy reveals structural examinations and the redistribution of cations between octahedral (505-428 cm⁻¹) and tetrahedral (653-603 cm⁻¹) locales. As the Co²⁺ cation is substituted with Ni²⁺, the coercive fields HC decrease from 2384 Oe to 241.93 Oe. Band gap energy rises as Ni concentration increases, which may be attributed to the fact that the ionic radii of Ni²⁺ ions are smaller than that of Co²⁺ ions, which results in a strong electrostatic interaction. On the contrary, except at x = 0.4, the dielectric constant decreases as the nickel concentration increases. According to the findings of this research work, nanoparticles are composed of Ni₀.₄ Co₀.₆ Fe₂ O₄ have demonstrated a promising value against S. aureus and E. coli, and it suggests a proposed model for their potential use as a source of antibacterial agent.Keywords: antimicrobial, band gap, citrate precursor, dielectric, nanoparticle
Procedia PDF Downloads 731660 Computational Fluid Dynamics Analysis of Convergent–Divergent Nozzle and Comparison against Theoretical and Experimental Results
Authors: Stewart A. Keir, Faik A. Hamad
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This study aims to use both analytical and experimental methods of analysis to examine the accuracy of Computational Fluid Dynamics (CFD) models that can then be used for more complex analyses, accurately representing more elaborate flow phenomena such as internal shockwaves and boundary layers. The geometry used in the analytical study and CFD model is taken from the experimental rig. The analytical study is undertaken using isentropic and adiabatic relationships and the output of the analytical study, the 'shockwave location tool', is created. The results from the analytical study are then used to optimize the redesign an experimental rig for more favorable placement of pressure taps and gain a much better representation of the shockwaves occurring in the divergent section of the nozzle. The CFD model is then optimized through the selection of different parameters, e.g. turbulence models (Spalart-Almaras, Realizable k-epsilon & Standard k-omega) in order to develop an accurate, robust model. The results from the CFD model can then be directly compared to experimental and analytical results in order to gauge the accuracy of each method of analysis. The CFD model will be used to visualize the variation of various parameters such as velocity/Mach number, pressure and turbulence across the shock. The CFD results will be used to investigate the interaction between the shock wave and the boundary layer. The validated model can then be used to modify the nozzle designs which may offer better performance and ease of manufacture and may present feasible improvements to existing high-speed flow applications.Keywords: CFD, nozzle, fluent, gas dynamics, shock-wave
Procedia PDF Downloads 2331659 Grey Wolf Optimization Technique for Predictive Analysis of Products in E-Commerce: An Adaptive Approach
Authors: Shital Suresh Borse, Vijayalaxmi Kadroli
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E-commerce industries nowadays implement the latest AI, ML Techniques to improve their own performance and prediction accuracy. This helps to gain a huge profit from the online market. Ant Colony Optimization, Genetic algorithm, Particle Swarm Optimization, Neural Network & GWO help many e-commerce industries for up-gradation of their predictive performance. These algorithms are providing optimum results in various applications, such as stock price prediction, prediction of drug-target interaction & user ratings of similar products in e-commerce sites, etc. In this study, customer reviews will play an important role in prediction analysis. People showing much interest in buying a lot of services& products suggested by other customers. This ultimately increases net profit. In this work, a convolution neural network (CNN) is proposed which further is useful to optimize the prediction accuracy of an e-commerce website. This method shows that CNN is used to optimize hyperparameters of GWO algorithm using an appropriate coding scheme. Accurate model results are verified by comparing them to PSO results whose hyperparameters have been optimized by CNN in Amazon's customer review dataset. Here, experimental outcome proves that this proposed system using the GWO algorithm achieves superior execution in terms of accuracy, precision, recovery, etc. in prediction analysis compared to the existing systems.Keywords: prediction analysis, e-commerce, machine learning, grey wolf optimization, particle swarm optimization, CNN
Procedia PDF Downloads 1131658 Biobased Toughening Filler for Polylactic Acid from Ultrafine Fully Vulcanized Powder Natural Rubber Grafted with Polymethylmethacrylate
Authors: Panyawutthi Rimdusit, Krittapas Charoensuk, Sarawut Rimdusit
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A biobased toughening filler for polylactic acid (PLA) based on natural rubber is developed in this work. Deproteinized natural rubber (DPNR) was modified by grafting polymerization with methyl methacrylate monomer (MMA) and further crosslinked by e-beam irradiation and spray drying process to achieve ultrafine full vulcanized powdered natural rubber grafted with polymethylmethacrylate (UFPNRg-PMMA) to solves in the challenges of incompatibility between natural rubber and PLA. Intriguingly, UFPNR-g-PMMA revealed outstanding and unique properties with minimal particle aggregation. The average particle size of rubber powder obtained from UFPNR-g-PMMA at PMMA grafting content of 20 phr reduced to 3.3±1.2 µm, compared to that of neat UFPNR of 5.3±2.3 µm which also showed partial particle aggregation. It is also found that the impact strength of the filled PLA was enhanced to 33.4±5.6 kJ/m2 at PLA/UFPNR-gPMMA 20 wt% compared to neat PLA of 9.6±3 kJ/m2. The thermal degradation temperature of the PLA composites was enhanced with increasing UFPNR-g-PMMA content without affecting the glass transition temperature of the composites. The fracture surface of PLA/ UFPNR-g-PMMA suggested internal cavitation and crazes are the main effects of rubber toughening PLA with substantial interfacial interaction between the filler and the matrix.Keywords: natural rubber, ultrafine fully vulcanized powder rubber, polylactic acid, polymer composites
Procedia PDF Downloads 111657 Dynamic Process of Single Water Droplet Impacting on a Hot Heptane Surface
Authors: Mingjun Xu, Shouxiang Lu
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Understanding the interaction mechanism between the water droplet and pool fire has an important significance in engineering application of water sprinkle/spray/mist fire suppression. The micro impact process is unclear when the droplet impacts on the burning liquid surface at present. To deepen the understanding of the mechanisms of pool fire suppression with water spray/mist, dynamic processes of single water droplet impinging onto a hot heptane surface are visualized with the aid of a high-speed digital camera at 2000 fps. Each test is repeated 20 times. The water droplet diameter is around 1.98 mm, and the impact Weber number ranges from 30 to 695. The heptane is heated by a hot plate to mimic the burning condition, and the temperature varies from 30 to 90°C. The results show that three typical phenomena, including penetration, crater-jet and surface bubble, are observed, and the pool temperature has a significant influence on the critical condition for the appearance of each phenomenon. A global picture of different phenomena is built according to impact Weber number and pool temperature. In addition, the pool temperature and Weber number have important influences on the characteristic parameters including maximum crater depth, crown height and liquid column height. For a fixed Weber number, the liquid column height increases with pool temperature.Keywords: droplet impact, fire suppression, hot surface, water spray
Procedia PDF Downloads 2431656 Cosmetic Surgery on the Rise: The Impact of Remote Communication
Authors: Bruno Di Pace, Roxanne H. Padley
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Aims: The recent increase in remote video interaction has increased the number of requests for teleconsultations with plastic surgeons in private practice (70% in the UK and 64% in the USA). This study investigated the motivations for such an increase and the underlying psychological impact on patients. Method: An anonymous web-based poll of 8 questions was designed and distributed to patients seeking cosmetic surgery through social networks in both Italy and the UK. The questions gathered responses regarding 1. Reasons for pursuing cosmetic surgery; 2. The effects of delays caused by the SARS-COV-2 pandemic; 3. The effects on mood; 4. The influence of video conferencing on body-image perception. Results: 85 respondents completed the online poll. Overall, 68% of respondents stated that seeing themselves more frequently online had influenced their decision to seek cosmetic surgery. The types of surgeries indicated were predominantly to the upper body and face (82%). Delays and access to surgeons during the pandemic were perceived as negatively impacting patients' moods (95%). Body-image perception and self-esteem were lower than in the pre-pandemic, particularly during lockdown (72%). Patients were more inclined to undergo cosmetic surgery during the pandemic, both due to the wish to improve their “lockdown face” for video conferencing (77%) and also due to the benefits of home recovery while in smart working (58%). Conclusions: Overall, findings suggest that video conferencing has led to a significant increase in requests for cosmetic surgery and the so-called “Zoom Boom” effect.Keywords: cosmetic surgery, remote communication, telehealth, zoom boom
Procedia PDF Downloads 1791655 Nondestructive Evaluation of Hidden Delamination in Glass Fiber Composite Using Terahertz Spectroscopy
Authors: Chung-Hyeon Ryu, Do-Hyoung Kim, Hak-Sung Kim
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As the use of the composites was increased, the detecting method of hidden damages which have an effect on performance of the composite was important. Terahertz (THz) spectroscopy was assessed as one of the new powerful nondestructive evaluation (NDE) techniques for fiber reinforced composite structures because it has many advantages which can overcome the limitations of conventional NDE techniques such as x-rays or ultrasound. The THz wave offers noninvasive, noncontact and nonionizing methods evaluating composite damages, also it gives a broad range of information about the material properties. In additions, it enables to detect the multiple-delaminations of various nonmetallic materials. In this study, the pulse type THz spectroscopy imaging system was devised and used for detecting and evaluating the hidden delamination in the glass fiber reinforced plastic (GFRP) composite laminates. The interaction between THz and the GFRP composite was analyzed respect to the type of delamination, including their thickness, size and numbers of overlaps among multiple-delaminations in through-thickness direction. Both of transmission and reflection configurations were used for evaluation of hidden delaminations and THz wave propagations through the delaminations were also discussed. From these results, various hidden delaminations inside of the GFRP composite were successfully detected using time-domain THz spectroscopy imaging system and also compared to the results of C-scan inspection. It is expected that THz NDE technique will be widely used to evaluate the reliability of composite structures.Keywords: terahertz, delamination, glass fiber reinforced plastic composites, terahertz spectroscopy
Procedia PDF Downloads 5921654 Pedagogical Practices of a Teacher in Students' Experience Tellings: A Conversation Analytic Study
Authors: Derya Duran, Christine Jacknick
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This study explores post-task reflections in an English as a Medium of Instruction (EMI) setting, and it specifically focuses on how a teacher performs pedagogical practices such as reformulating, extending and evaluating following students’ spontaneous experience tellings in EMI classrooms. The data consist of 30 hours of video recordings from two EMI content classes, which were recorded for an academic term at a university in Turkey. The course, Guidance, is offered to fourth year undergraduate students as a compulsory course in the Department of Educational Sciences. The participants (n=78) study at the Faculty of Education, majoring in different educational departments (i.e., Computer Education and Instructional Technology, Elementary Education, Foreign Language Education). Using conversation analysis, we demonstrate that the teacher employs a variety of interactional resources to elicit (i.e., asking specific questions) and also provides (i.e., giving scientific information) as much content as possible, which also sheds light on the institutional fingerprints of the current research context. The study contributes to the existing research by unpacking articulation of personal experiences and cultivation of collaborativeness in classroom interaction. Moreover, describing the dialogic nature of these specific occasions, the study demonstrates how teacher and students address learning tasks together (collectivity), how they orient to each other turns interactionally (reciprocity), and how they keep the pedagogical focus in mind (purposefulness).Keywords: conversation analysis, English as a medium of instruction, higher education, post-task reflections
Procedia PDF Downloads 1511653 Omani Community in Digital Age: A Study of Omani Women Using Back Channel Media to Empower Themselves for Frontline Entrepreneurship
Authors: Sangeeta Tripathi, Muna Al Shahri
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This research article presents the changing role and status of women in Oman. Transformation of women’s status started with the regime of His Majesty Sultan Qaboos Bin Said in 1970. It is always desired by the Sultan to enable women in all the ways for the balance growth of the country. Forbidding full face veil for women in public offices is one of the best efforts for their empowerment. Women education is also increasing rapidly. They are getting friendly with new information communication technology and using different social media applications such as WhatsApp, Instagram and Facebook for interaction and economic growth. Though there are some traditional and tribal boundaries, women are infused with courage and enjoying fair treatment and equal opportunities in different career positions. The study will try to explore changing mindset of young Omani women towards these traditional tribal boundaries, cultural heritage, business and career: ‘How are young Omani women making balance between work and social prestige?’, ‘How are they preserving their cultural values, embracing new technologies and approaching social network to enhance their economic power.’ This paper will discover their hurdles while using internet for their new entrepreneur. It will also examine the prospects of online business in Oman. The mixed research methodology is applied to find out the result.Keywords: advertising, business, entrepreneurship, tribal barrier
Procedia PDF Downloads 3041652 Community Interpreting in the Process of Asylum Seeking in Brazil
Authors: Fernanda Garcia
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With the recent growth of refugees in the world, there has been an exponential increase in requests for asylum seeking in Brazil. When asylum seekers arrive in the country, the government initiates a process to evaluate the case, which will serve as grounds to determine the refugee status of the asylum seekers. During this process, an interview where the migrant has the chance to tell their story takes place. The aim of this article is to analyse how community interpreting is conducted in Brazil with regard to asylum seeking, as well as to analyse the role of the interpreter in the context of these official interviews to request refuge in Brazil. We investigate how the presence of an interpreter influences this interview, but more specifically, we study some of the linguistic techniques used by the interpreter in order to make the interaction more effective, as well as the challenges and difficulties they encounter during the interview. To do so, surveys with the interpreters took place, in addition to on-site observations. The interpreters involved in this research are volunteers as part of an extra-curricular extension programme from the University of Brasilia, in Brazil. Community Interpreting is a somewhat new field in Brazil, still facing several obstacles, such as the lack of professional community interpreters. This research illustrates some of these issues and, thus, has the potential to foster Brazilian literature in the matter as well as help understand the role of the interpreter in the interview to seek asylum in Brazil. The refugees’ situation in the world is certainly a pressing matter, and the language barrier is an issue of great importance. Hence, translation and interpretation studies have a fundamental role in this area, when it comes to contributing to a more inclusive world to those in need.Keywords: asylum seeking, community interpreting, interviews, refugees
Procedia PDF Downloads 1371651 Numerical Simulation of Two-Dimensional Flow over a Stationary Circular Cylinder Using Feedback Forcing Scheme Based Immersed Boundary Finite Volume Method
Authors: Ranjith Maniyeri, Ahamed C. Saleel
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Two-dimensional fluid flow over a stationary circular cylinder is one of the bench mark problem in the field of fluid-structure interaction in computational fluid dynamics (CFD). Motivated by this, in the present work, a two-dimensional computational model is developed using an improved version of immersed boundary method which combines the feedback forcing scheme of the virtual boundary method with Peskin’s regularized delta function approach. Lagrangian coordinates are used to represent the cylinder and Eulerian coordinates are used to describe the fluid flow. A two-dimensional Dirac delta function is used to transfer the quantities between the sold to fluid domain. Further, continuity and momentum equations governing the fluid flow are solved using fractional step based finite volume method on a staggered Cartesian grid system. The developed code is validated by comparing the values of drag coefficient obtained for different Reynolds numbers with that of other researcher’s results. Also, through numerical simulations for different Reynolds numbers flow behavior is well captured. The stability analysis of the improved version of immersed boundary method is tested for different values of feedback forcing coefficients.Keywords: Feedback Forcing Scheme, Finite Volume Method, Immersed Boundary Method, Navier-Stokes Equations
Procedia PDF Downloads 3051650 Software Vulnerability Markets: Discoverers and Buyers
Authors: Abdullah M. Algarni, Yashwant K. Malaiya
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Some of the key aspects of vulnerability-discovery, dissemination, and disclosure-have received some attention recently. However, the role of interaction among the vulnerability discoverers and vulnerability acquirers has not yet been adequately addressed. Our study suggests that a major percentage of discoverers, a majority in some cases, are unaffiliated with the software developers and thus are free to disseminate the vulnerabilities they discover in any way they like. As a result, multiple vulnerability markets have emerged. In some of these markets, the exchange is regulated, but in others, there is little or no regulation. In recent vulnerability discovery literature, the vulnerability discoverers have remained anonymous individuals. Although there has been an attempt to model the level of their efforts, information regarding their identities, modes of operation, and what they are doing with the discovered vulnerabilities has not been explored. Reports of buying and selling of the vulnerabilities are now appearing in the press; however, the existence of such markets requires validation, and the natures of the markets need to be analysed. To address this need, we have attempted to collect detailed information. We have identified the most prolific vulnerability discoverers throughout the past decade and examined their motivation and methods. A large percentage of these discoverers are located in Eastern and Western Europe and in the Far East. We have contacted several of them in order to collect first-hand information regarding their techniques, motivations, and involvement in the vulnerability markets. We examine why many of the discoverers appear to retire after a highly successful vulnerability-finding career. The paper identifies the actual vulnerability markets, rather than the hypothetical ideal markets that are often examined. The emergence of worldwide government agencies as vulnerability buyers has significant implications. We discuss potential factors that can impact the risk to society and the need for detailed exploration.Keywords: risk management, software security, vulnerability discoverers, vulnerability markets
Procedia PDF Downloads 2531649 Attitudes to Thinking and Learning in Sustainability Education: Case Basics of Natural Stone Industry in Circular Economy
Authors: Anne-Marie Tuomala
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Education for sustainable development (ESD) aims to provide students with the attitudes, values, and behaviors necessary for the contribution to sustainability. The research was implemented as a part of the Horizons Europe research project, where each partner organization had at least one pilot project locally. The pilot in question was an online course about the basics of the natural stone industry in Finland and its sustainability and circular economy aspects. The course was open to all students of applied universities in Finland, and it was implemented twice during the research. The Stone from Finland association participated in the course design, and it was also an expert in the local context and real-life provider. The multiple case-study method was chosen, as it enables purposeful sampling of cases that are tailored to the specific study. It was also assumed that it predicts quite comparable results of two different course implementations of the course with the same topic and content. The Curtin University of Technology’s Attitudes Towards Thinking and Learning Survey was adapted. The results show the importance of the trans-disciplinary nature of sustainability education. In addition, the new industry areas with the general - but also industry-specific sustainability issues - must be introduced to students and encourage them to do critically reflective learning. Surveys that guide them to analyze their own attitudes to thinking and learning may expose students to their weaknesses but also result in forms of more active sustainability interaction.Keywords: education for sustainable development, learning attitudes, learning of circular economy, virtual learning
Procedia PDF Downloads 441648 Chatter Prediction of Curved Thin-walled Parts Considering Variation of Dynamic Characteristics Based on Acoustic Signals Acquisition
Authors: Damous Mohamed, Zeroudi Nasredine
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High-speed milling of thin-walled parts with complex curvilinear profiles often encounters machining instability, commonly referred to as chatter. This phenomenon arises due to the dynamic interaction between the cutting tool and the part, exacerbated by the part's low rigidity and varying dynamic characteristics along the tool path. This research presents a dynamic model specifically developed to predict machining stability for such curved thin-walled components. The model employs the semi-discretization method, segmenting the tool trajectory into small, straight elements to locally approximate the behavior of an inclined plane. Dynamic characteristics for each segment are extracted through experimental modal analysis and incorporated into the simulation model to generate global stability lobe diagrams. Validation of the model is conducted through cutting tests where acoustic intensity is measured to detect instabilities. The experimental data align closely with the predicted stability limits, confirming the model's accuracy and effectiveness. This work provides a comprehensive approach to enhancing machining stability predictions, thereby improving the efficiency and quality of high-speed milling operations for thin-walled parts.Keywords: chatter, curved thin-walled part, semi-discretization method, stability lobe diagrams
Procedia PDF Downloads 271647 Sensitivity Analysis of Principal Stresses in Concrete Slab of Rigid Pavement Made From Recycled Materials
Authors: Aleš Florian, Lenka Ševelová
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Complex sensitivity analysis of stresses in a concrete slab of the real type of rigid pavement made from recycled materials is performed. The computational model of the pavement is designed as a spatial (3D) model, is based on a nonlinear variant of the finite element method that respects the structural nonlinearity, enables to model different arrangements of joints, and the entire model can be loaded by the thermal load. Interaction of adjacent slabs in joints and contact of the slab and the subsequent layer are modeled with the help of special contact elements. Four concrete slabs separated by transverse and longitudinal joints and the additional structural layers and soil to the depth of about 3m are modeled. The thickness of individual layers, physical and mechanical properties of materials, characteristics of joints, and the temperature of the upper and lower surface of slabs are supposed to be random variables. The modern simulation technique Updated Latin Hypercube Sampling with 20 simulations is used. For sensitivity analysis the sensitivity coefficient based on the Spearman rank correlation coefficient is utilized. As a result, the estimates of influence of random variability of individual input variables on the random variability of principal stresses s1 and s3 in 53 points on the upper and lower surface of the concrete slabs are obtained.Keywords: concrete, FEM, pavement, sensitivity, simulation
Procedia PDF Downloads 3301646 Effect of Early Therapeutic Intervention for the Children With Autism Spectrum Disorders: A Quasi Experimental Design
Authors: Sultana Razia
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The number of children whose social, communication and behavior pattern is affected due to mental and developmental conditions is on the rise. Most of these conditions develop to uncontrollable levels because of ignorance and unaware about their child’s condition. The many myths surrounding mental or developmental conditions are a major cause of families of affected children to develop bitterness and to shy off from seeking appropriate help in time. Several early intervention programs have been put in place, and the number of beneficiaries of these programs is increasing by the day. This research seeks to look into early intervention programs and their effectiveness. The purpose of this study was to investigate the effect of early therapeutic intervention for the children with autism spectrum disorder. Participants were 140 children with autism spectrum disorder from Autism Corner in a selected rehabilitation center of Bangladesh. This study included children who are at age of 18-month to 36-month and who were taking occupational therapy and speech and language therapy from the autism center. They were primarily screened using M-CHAT; however, children with other physical disability or medical conditions excluded. 3-months interventions of 6 sessions per week are a minimum of 45-minutes long per session, one to one interaction followed by parent-led structured home-based therapy were provided. The results indicated that early intensive therapeutic intervention improve understanding, social skills and sensory skills. It can be concluded that therapeutic early intervention a positive effect on diminishing symptoms of Autism Spectrum Disorder.Keywords: M-CHAT, ASD, sensory cheeklist, OT
Procedia PDF Downloads 741645 Assessment of the Indices in Converting Affect Rural to Urban Settlements Case Study: Torqabe and Shandiz Rural Districts in Iran
Authors: Fahimeh Khatami, Elham Sanagar Darbani, Behnosh Khir Khah, R.Khatami
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Rural and ruralism is one of the residential forms that form in special natural areas, and the Interaction between their internal and external forces cause developments and changes that are different in time and space. Over time, historical developments, social and economic changes in the political system cause developments and rapid growth of the rural to urban settlements. However, criteria for recognizing rural settlements to the city are different in every land. One of the problems in modern plan is inattention to indicators and criteria of changing these settlements to the city. The method of this research is a type of applied and compilation research and library and field methods are used in it. And also qualitative and quantitative indicators have been provided while collecting documents and studies from rural districts like Dehnow, Virani, Abardeh, Zoshk, Nowchah, Jaqarq in tourism area of Mashhad. In this research, the used tool is questionnaire and for analyzing quantitative variables by Morris and Mac Granahan examination, the importance of each factor and the development settlements are evaluated, and the rural that can convert to the city was defined. In result, according to Askalvgram curve obtained from analysis, it was found that among the mentioned villages, Virani and Nowchah rural districts have this ability to convert to the city; Zoshk rural district will be converting to the city in future and Dehnow, Abardeh and Jaqarq rural districts won’t be converting.Keywords: rural settlements, city, indicators, Torqabe and Shandiz rural districts
Procedia PDF Downloads 2681644 Navigating Urban Childcare Challenges: Perspectives of Dhaka City Parents
Authors: Md. Shafiullah
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This study delves into the evolving landscape of urban childcare in Bangladesh, focusing on the experiences and challenges faced by parents in Dhaka city. This paper argues that the traditional childcare arrangement of city families is inadequate to meet the development needs of children. The study aims to explore the childcare challenges faced by urban parents as they transition from traditional family-based childcare networks to alternative caregiving arrangements amidst urbanization, economic shifts, and social transformations. Utilizing a mixed-method research approach, combining quantitative surveys (n = 200) and four qualitative interviews, the research examines the parental viewpoints on childcare practices and the role of societal norms and values. The study finds childcare crises in both the family and daycare settings. In family care, caregiving suffers from the less availability of grandparents, a lack of skills of caregivers, and a lack of child interaction. As for the daycare, it is affected by the absence of appropriate policies, a lack of quality, health and safety concerns, affordability issues, and cultural concerns. Additionally, the study highlights inadequacies in childcare policies and regulatory frameworks, calling for comprehensive reforms to address the childcare vacuum in urban areas. By shifting the focus from developed to developing countries, this study contributes to the literature and suggests policy implications for Bangladesh and beyond.Keywords: childcare, child development, childcare policy, daycare, Bangladesh
Procedia PDF Downloads 561643 Evaluation of Nitrogen Fixation Capabilities of Selected Pea Lines Grown under Different Environmental Conditions in Canadian Prairie
Authors: Chao Yang, Rosalind Bueckert, Jeff Schoenau, Axel Diederichsen, Hossein Zakeri, Tom Warkentin
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Pea is a very popular pulse crop that widely grew in Western Canadian prairie. However, the N fixation capabilities of these pea lines were not well evaluated under local environmental conditions. In this study, 2 supernodulating mutants Frisson P64 Sym29, Frisson P88 Sym28 along with their wild parent Frisson, 1 hypernodulating mutant Rondo-nod3 (fix+) along with its wild parent Rondo, 1 non-nodulating mutant Frisson P56 (nod-) and 2 commercial pea cultivar CDC Meadow and CDC Dakota which are widely planted in Western Canada were selected in order to evaluate the capabilities of their BNF, biomass, and yield production in symbiosis with R. leguminosarumbv. viciae, Our results showed different environmental conditions and variation of pea lines could both significantly impact days to flowering (DTF), days to podding (DTP), biomass and yield of tested pea lines (P < 0.0001), suggesting consideration of environmental factors could be important when selecting pea cultivar for local farming under different soil zones in Western Canada. Significant interaction effects between environmental conditions and pea lines were found on pea N fixation as well (P = 0.001), suggesting changes in N fixation capability of the same pea cultivar when grown under different environmental conditions. Our results provide useful information for farming and better opportunity for selection of pea cultivars with higher N-fixing capacity during breeding programs in Western Canada.Keywords: Canadian prairie, environmental condition, N fixation, pea cultivar
Procedia PDF Downloads 3441642 Appraisal of Transaction Cost in South African Construction Projects
Authors: Kenneth O. Otasowie, Matthew Ikuabe, Clinton Aigbavboa, Ayodeji Oke
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Construction project cost are not only made up of production costs. This cost comprises of many other elements such as the preparation of a bidding document, cost estimations, drafting contractual agreements and monitoring that contractual obligations are met. Several studies have stressed the need for transaction costs (TC) to be defined in a way that covers all phases of a project and not only the pre-contract phase. Hence, this study aims to appraise transaction cost in South African (SA) construction projects by assessing what constitutes transaction cost, influencing factors and possible optimisation measures. A survey design was adopted. A total number of eighty (80) questionnaires were administered to quantity surveyors, procurement managers and project managers in Guateng Province, SA and seventy-two (72) were returned and found suitable for analysis. Collected data was analysed using percentage, mean item score, standard deviation, one-sample t-test. The findings show that external technical interaction, uncertainty, human factors are the most significant constituents of TC in SA, while technical competency, experience in similar project type and project characteristics are the leading influencing factors. Furthermore, understanding project characteristics, clear communication and technically competent project teams are most of the significant measures for optimising TC in SA construction projects. Therefore, this study recommends that a competent project team and a clear communication are fundamental to proper management of TC in SA construction projects.Keywords: construction projects, project cost, South Africa, transaction cost
Procedia PDF Downloads 991641 The Transcriptome of Carnation (Dianthus Caryophyllus) of Elicited Cells with Fusarium Oxysporum f.sp. Dianthi
Authors: Juan Jose Filgueira, Daniela Londono-Serna, Liliana Maria Hoyos
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Carnation (Dianthus caryophyllus) is one of the most important products of exportation in the floriculture industry worldwide. Fusariosis is the disease that causes the highest losses on farms, in particular the one produced by Fusarium oxysporum f.sp. dianthi, called vascular wilt. Gene identification and metabolic routes of the genes that participate in the building of the plant response to Fusarium are some of the current targets in the carnation breeding industry. The techniques for the identifying of resistant genes in the plants, is the analysis of the transcriptome obtained during the host-pathogen interaction. In this work, we report the cell transcriptome of different varieties of carnation that present differential response from Fusarium oxysporum f.sp. dianthi attack. The cells of the different hybrids produced in the outbreeding program were cultured in vitro and elicited with the parasite in a dual culture. The isolation and purification of mRNA was achieved by using affinity chromatography Oligo dT columns and the transcriptomes were obtained by using Illumina NGS techniques. A total of 85,669 unigenes were detected in all the transcriptomes analyzed and 31,000 annotations were found in databases, which correspond to 36.2%. The library construction of genic expression techniques used, allowed to recognize the variation in the expression of genes such as Germin-like protein, Glycosyl hydrolase family and Cinnamate 4-hydroxylase. These have been reported in this study for the first time as part of the response mechanism to the presence of Fusarium oxysporum.Keywords: Carnation, Fusarium, vascular wilt, transcriptome
Procedia PDF Downloads 1501640 Physics Recitations for College Physics Courses Using Breakout Rooms during COVID Pandemic
Authors: Pratheesh Jakkala
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This paper addresses the use of breakout sessions to conduct successful weekly physics recitations for College Physics I and II at a large University in remote teaching method during COVID-19 pandemic. All breakout sessions are synchronous, conducted live, and handled by teaching assistants. A two-prong approach is used to maintain the integrity of recitations. Three different conference platforms WebEx, Zoom, and Canvas conferences, were tested, and BigBlue button using Canvas was adopted. The results and experiences of all three learning platforms are presented in this paper. Recitation questions were assigned on WebAssign learning platform and a standard five-question template developed by the instructor was used for group discussions and active peer-peer engagement. Breakout sessions feature of BigBlueButton in Canvas conferences was successfully implemented. Each breakout session consists of a team of 4 students. An online whiteboard, chat window options were used for live teamwork. Student peer-peer interactions, Teaching Assistants’ interaction with students were video and audio recorded. A total of 72 students in College Physics II and 55 students in College Physics I was enrolled. 82% of students agreed that method under study is better than previous methods. The study addressed the quality of student teamwork, student attitude towards problem-solving, and student performance in the exams.Keywords: recitations, breakout rooms, online learning platforms, COVID pandemic
Procedia PDF Downloads 1101639 Evaluation of the Practice of Veterinary Pharmacy
Authors: Maria Magdy Danial Riad
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Background: In the United Kingdom (UK), pharmacists' roles have expanded considerably in recent decades to encompass clinical practice through more direct patient care. However, dispensing and compounding remain core activities for pharmacists. A lack of marketed preparations for species-specific animal use results in veterinary pharmacy practice compounding, retaining its prominence. Current participation by pharmacists to support this sphere of practice would appear to be minimal. Objectives: This study was undertaken to determine the opinions and views toward the practice of veterinary pharmacy by a cross-sectional group of pharmacists. Methods: Research data were collected via a self-administered survey questionnaire distributed at the 2012 annual conference of the Royal Pharmaceutical Society. Sampling was purposive, with a random distribution of the questionnaire to pharmacists during the conference sessions. Key findings: Interaction by pharmacists with veterinary pharmacies is currently minimal, primarily due to a lack of knowledge of veterinary medicines. Respondents revealed a lack of veterinary pharmacy courses during their undergraduate studies. This has led to situations where some veterinary prescriptions are dispensed without adequate checks being performed by the pharmacist. Pharmacists, on occasion, do not dispense veterinary prescriptions presented to them due to insufficient knowledge of veterinary medicines and/or a lack of consultable reference sources. The effect on practice is that pharmacists do not always participate as fully as would seem logical. Conclusions: Pharmacists' participation in veterinary pharmacy is limited by a lack of knowledge of veterinary medicines, mostly resulting from inadequate tuition on veterinary pharmacy during their initial education.Keywords: veterinary pharmacy, veterinary medicines, pharmacy education, pharmacists continuing professional development
Procedia PDF Downloads 831638 Understanding the Nexus between Dengue and Climate Variability
Authors: Edilene Mercedes Mauer Machado, Carolina Hadassa Marques Karoly, Amanda Britz, Claudineia Brazil
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The El Niño phenomenon, characterized by the anomalous warming of surface waters in the Equatorial Pacific Ocean, can influence weather patterns in various parts of the world, including the occurrence of extreme events such as droughts or heavy rainfall. Studies have suggested a relationship between El Niño and an increase in the incidence of dengue in certain areas. During El Niño periods, there can be changes in climatic conditions, such as increased temperatures and reduced rainfall in certain tropical and subtropical regions. These conditions can favor the reproduction of the Aedes aegypti mosquito, the vector for dengue transmission. Research aims to investigate how climate events like El Niño and La Niña can influence the incidence and transmission of dengue. The results have shown that, on average, there was a significant increase in dengue cases during La Niña years compared to years of climatic neutrality, contradicting the findings of Hopp et al. (2015). The study also highlighted that regions affected by El Niño exhibited greater variability in dengue incidence. However, it is important to emphasize that the effects of El Niño on dengue transmission can vary depending on the region and local factors, such as socioeconomic context and implemented control measures, as described by Johansson et al. (2009). Not all areas affected by El Niño will necessarily experience an increase in dengue incidence, and the interaction between climate and disease transmission is complex.Keywords: anomalous warming, climatic patterns, dengue incidence, extreme events
Procedia PDF Downloads 103