Search results for: simulated translator-client relations
1284 SAR and B₁ Considerations for Multi-Nuclear RF Body Coils
Authors: Ria Forner
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Introduction: Due to increases in the SNR at 7T and above, it becomes more favourable to make use of X-nuclear imaging. Integrated body coils tuned to 120MHz for 31P, 79MHz for 23Na, and 75 MHz for 13C at 7T were simulated with a human male, female, or child body model to assess strategies of use for metabolic MR imaging in the body. Methods: B1 and SAR efficiencies in the heart, liver, spleen, and kidneys were assessed using numerical simulations over the three frequencies with phase shimming. Results: B1+ efficiency is highly variable over the different organs, particularly for the highest frequency; however, local SAR efficiency remains relatively constant over the frequencies in all subjects. Although the optimal phase settings vary, one generic phase setting can be identified for each frequency at which the penalty in B1+ is at a max of 10%. Discussion: The simulations provide practical strategies for power optimization, B1 management, and maintaining safety. As expected, the B1 field is similar at 75MHz and 79MHz, but reduced at 120MHz. However, the B1 remains relatively constant when normalised by the square root of the peak local SAR. This is in contradiction to generalized SAR considerations of 1H MRI at different field strengths, which is defined by global SAR instead. Conclusion: Although the B1 decreases with frequency, SAR efficiency remains constant throughout the investigated frequency range. It is possible to shim the body coil to obtain a maximum of 10% extra B1+ in a specific organ in a body when compared to a generic setting.Keywords: birdcage, multi-nuclear, B1 shimming, 7 Tesla MRI, liver, kidneys, heart, spleen
Procedia PDF Downloads 531283 Catchment Yield Prediction in an Ungauged Basin Using PyTOPKAPI
Authors: B. S. Fatoyinbo, D. Stretch, O. T. Amoo, D. Allopi
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This study extends the use of the Drainage Area Regionalization (DAR) method in generating synthetic data and calibrating PyTOPKAPI stream yield for an ungauged basin at a daily time scale. The generation of runoff in determining a river yield has been subjected to various topographic and spatial meteorological variables, which integers form the Catchment Characteristics Model (CCM). Many of the conventional CCM models adapted in Africa have been challenged with a paucity of adequate, relevance and accurate data to parameterize and validate the potential. The purpose of generating synthetic flow is to test a hydrological model, which will not suffer from the impact of very low flows or very high flows, thus allowing to check whether the model is structurally sound enough or not. The employed physically-based, watershed-scale hydrologic model (PyTOPKAPI) was parameterized with GIS-pre-processing parameters and remote sensing hydro-meteorological variables. The validation with mean annual runoff ratio proposes a decent graphical understanding between observed and the simulated discharge. The Nash-Sutcliffe efficiency and coefficient of determination (R²) values of 0.704 and 0.739 proves strong model efficiency. Given the current climate variability impact, water planner can now assert a tool for flow quantification and sustainable planning purposes.Keywords: catchment characteristics model, GIS, synthetic data, ungauged basin
Procedia PDF Downloads 3151282 The Effects of Anthropomorphism on Complex Technological Innovations
Authors: Chyi Jaw
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Many companies have suffered as a result of consumers’ rejection of complex new products and experienced huge losses in the market. Marketers have to understand what block from new technology adoption or positive product attitude may exist in the market. This research examines the effects of techno-complexity and anthropomorphism on consumer psychology and product attitude when new technologies are introduced to the market. This study conducted a pretest and a 2 x 2 between-subjects experiment. Four simulated experimental web pages were constructed to collect data. The empirical analysis tested the moderation-mediation relationships among techno-complexity, technology anxiety, ability, and product attitude. These empirical results indicate (1) Techno-complexity of an innovation is negatively related to consumers’ product attitude, as well as increases consumers’ technology anxiety and reduces their self-ability perception. (2) Consumers’ technology anxiety and ability perception towards an innovation completely mediate the relationship between techno-complexity and product attitude. (3) Product anthropomorphism is positively related to consumers’ attitude of new technology, and also significantly moderates the effect of techno-complexity in the hypothesized model. In this work, the study presents the moderation-mediation model and the effects of anthropomorphized strategy, which describes how managers can better predict and influence the diffusion of complex technological innovations.Keywords: ability, anthropomorphic effect, innovation, techno-complexity, technology anxiety
Procedia PDF Downloads 1851281 Intergenerational Technology Learning in the Family
Authors: Chih-Chun Wu
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Learning information and communication technologies (ICT) helps people survive in current society. For the internet generation also referred as digital natives, learning new technology is like breathing; however, for the elder generations also called digital immigrants, including parents and grandparents, learning new technology could be challenged and frustrated. While majority research focused on the effects of elders’ ICT learning, less attention was paid to the help that the elders got from their other family members while learning ICT. This study utilized the anonymous questionnaire to survey 3,749 undergraduates and demonstrated that families are great places for intergenerational technology learning to be carried out. Results from this study confirmed that in the family, the younger generation both helped set up technology products and educated the elder ones needed technology knowledge and skills. The family elder members in this study applied to those who lived under the same roof with relative relations. Results from this study revealed that 2,331 (62.2%) and 2,656 (70.8%) undergraduates revealed that they helped their family elder members set up and taught them how to use LINE respectively. In addition, 1,481 (49.1%) undergraduates helped their family elder members set up, and 2,222 (59.3%) taught them. When it came to Apps, 2,527 (67.4%) helped their family elder members download them, and 2,876 (76.7%) taught how to use them. As for search engine, 2,317 (61.8%) undergraduates taught their family elders. Furthermore, 3,118 (83.2%), 2,639 (70.4%) and 2,004 (53.7%) undergraduates illustrated that they taught their family elder members smartphones, computers and tablets respectively. Meanwhile, only 904 (24.2%) undergraduates taught their family elders how to make a doctor appointment online. This study suggests to making good use of intergenerational technology learning in the family, since it increases family elders’ technology capital, and thus strengthens our country’s human capital and competitiveness.Keywords: intergenerational technology learning, adult technology learning, family technology learning, ICT learning
Procedia PDF Downloads 2271280 Numerical Simulation of Three-Dimensional Cavitating Turbulent Flow in Francis Turbines with ANSYS
Authors: Raza Abdulla Saeed
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In this study, the three-dimensional cavitating turbulent flow in a complete Francis turbine is simulated using mixture model for cavity/liquid two-phase flows. Numerical analysis is carried out using ANSYS CFX software release 12, and standard k-ε turbulence model is adopted for this analysis. The computational fluid domain consist of spiral casing, stay vanes, guide vanes, runner and draft tube. The computational domain is discretized with a three-dimensional mesh system of unstructured tetrahedron mesh. The finite volume method (FVM) is used to solve the governing equations of the mixture model. Results of cavitation on the runner’s blades under three different boundary conditions are presented and discussed. From the numerical results it has been found that the numerical method was successfully applied to simulate the cavitating two-phase turbulent flow through a Francis turbine, and also cavitation is clearly predicted in the form of water vapor formation inside the turbine. By comparison the numerical prediction results with a real runner; it’s shown that the region of higher volume fraction obtained by simulation is consistent with the region of runner cavitation damage.Keywords: computational fluid dynamics, hydraulic francis turbine, numerical simulation, two-phase mixture cavitation model
Procedia PDF Downloads 5481279 Development and in vitro Characterization of Loteprednol Etabonate-Loaded Polymeric Nanoparticles for Ocular Delivery
Authors: Abhishek Kumar Sah, Preeti K. Suresh
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Effective drug delivery to the eye is a massive challenge, due to complicated physiological ocular barriers, rapid washout by tear and nasolachrymal drainage. Thus, most of the conventional ophthalmic formulations face the problem of low ocular bioavailability. Ophthalmic drug therapy can be improved by enhancing the precorneal drug retention along with improved drug penetration. The aim of the present investigation was to develop and evaluate a biodegradable polymer poly (D, L-lactide-co-glycolide) (PLGA) coated nanoparticulate carrier of loteprednol etabonate. PLGA nanoparticles were prepared by modified emulsification/solvent diffusion method using high-speed homogenizer followed by sonication. The nanoparticles were characterized for various parameters such as particle size, zeta potential, polydispersity index, X-ray powder diffraction (XRD), Transmission electron microscopy (TEM), in vitro drug release profile and stability. The prepared nanocarriers displayed mean particle size in the range of 271.7 to 424.4 nm, with zeta potential less than –10 mV. In vitro release in simulated tear fluid (STF) nanocarrier showed an extended release profile of loteprednol etabonate. TEM confirmed the spherical morphology and smooth surface of the particles. All the prepared formulations were found to be stable at varying temperatures.Keywords: drug delivery, ocular delivery, polymeric nanoparticles, loteprednol etabonate
Procedia PDF Downloads 5441278 Making New Theoretical Insights into Violence: The Temporal and Spatial Relevance of Blood Spatter Crime Scene Investigations
Authors: Simone Jane Dennis
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This paper leverages the spatial and temporal investigative strategy utilized by crime scene investigators – blood spatter work– to engage with the real and metaphorical memorialization of blood-soaked places. It uses this key trope with phenomenological sensibility, to trace the physical and temporal movement of blood outbound from the human body to sites beyond. Working backward, as crime scene investigators do, this paper traces the importance of both space and time and their confluence, to developing a comprehensive theory of violence. To do this work, the paper engages a range of geo-violent scales, from murder scenes to genocides, to both engage an extraordinarily replete literature of bloodshed across history and to move beyond analyses of how significance is assigned to the sites in which blood comes to rest to instead consider the importance of space and time to the structure of violence itself. It is in this regard that the kind of investigative work upon which blood spatter analysis depends is crucial: it engages time and space in reverse to understand the microscopic relations between bodies, places, and numerous (biological, clock, and seasonal) temporalities. Considering the circumstances under which blood escaped a body, the details of its destination in place, and the temporal circumstances of corporal departure, is crucial to making new knowledge about the peculiar temporality and spatiality of violence itself.Keywords: blood, crime scenes, temporality, violence
Procedia PDF Downloads 591277 Efficient Numerical Simulation for LDC
Authors: Badr Alkahtani
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In this poster, numerical solutions of two-dimensional and three-dimensional lid driven cavity are presented by solving the steady Navier-Stokes equations at high Reynolds numbers where it becomes difficult. Lid driven cavity is where the a fluid contained in a cube and the upper wall is moving. In two dimensions, we use the streamfunction-vorticity formulation to solve the problem in a square domain. A numerical method is employed to discretize the problem in the x and y directions with a spectral collocation method. The problem is coded in the MATLAB programming environment. Solutions at high Reynolds numbers are obtained up to Re=20000 on a fine grid of 131 * 131. Also in this presentation, the numerical solutions for the three-dimensional lid-driven cavity problem are obtained by solving the velocity-vorticity formulation of the Navier-Stokes equations (which is the first time that this has been simulated with special boundary conditions) for various Reynolds numbers. A spectral collocation method is employed to discretize the y and z directions and a finite difference method is used to discretize the x direction. Numerical solutions are obtained for Reynolds number up to 200. , The work prepared here is to show the efficiency of methods used to simulate the physical problem where accurate simulations of lid driven cavity are obtained at high Reynolds number as mentioned above. The result for the two dimensional problem is far from the previous researcher result.Keywords: lid driven cavity, navier-stokes, simulation, Reynolds number
Procedia PDF Downloads 7041276 Investigating Transformative Practices in the Bangladeshi Classroom
Authors: Rubaiyat Jahan, Nasreen Sultana Mitu
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This paper examines the theoretical construct of transformative practices, and reports some evidence of transformative practices from a couple of Bangladeshi English teachers. The idea of transformative practices calls for teachers’ capabilities to invest their intellectual labor in teaching with an assumption that along with the academic advancement of the learners, it aims for the personal transformation for both the learners as well for themselves. Following an ethnographic research approach, data for this study were collected through in-depth interviews, informal talks and classroom observations for a period of one year. In relevance to the English classroom of the Bangladeshi context, from this study, references of transformative practices have been underlined from the participant teachers’ views on English language teaching as well as from their actual practices. According to data of this research, some evidence of transformative practices in the form of critical language awareness and personal theories of practices emerge from the participants’ articulation of the beliefs on teaching; and from the participant teachers’ classroom practices evidence of self-directed acts of teaching, self-directed acts of professional development, and liberatory autonomy have been highlighted as the reflections of transformative practices. The implication of this paper refers to the significance of practicing teachers’ articulation of beliefs and views on teaching along with their orientation to critical pedagogical relations.Keywords: critical language awareness, personal theories of practice, teacher autonomy, transformative practices
Procedia PDF Downloads 2161275 Correlations Between Electrical Resistivity and Some Properties of Clayey Soils
Authors: F. A. Hassona, M. M. Abu-Heleika, M. A. Hassan, A. E. Sidhom
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Application of electrical measurements to evaluate engineering properties of soils has gained a wide, promising field of research in recent years. So, understanding of the relation between in-situ electrical resistivity of clay soil, and their mechanical and physical properties consider a promising field of research. This would assist in introducing a new technique for the determination of soil properties based on electrical resistivity. In this work soil physical and mechanical properties of clayey soil have been determined by experimental tests and correlated with the in-situ electrical resistivity. The research program was conducted through measuring fifteen vertical electrical sounding stations along with fifteen selected boreholes. These samples were analyzed and subjected to experimental tests such as physical tests namely bulk density, water content, specific gravity, and grain size distribution, and Attereberg limits tests. Mechanical test was also conducted such as direct shear test. The electrical resistivity data were interpreted and correlated with each one of the measured experimental parameters. Based on this study mathematical relations were extracted and discussed. These results exhibit an excellent match with the results reported in the literature. This study demonstrates the utility of the developed methodology for determining the mechanical properties of soils easily and rapidly depending on their electrical resistivity measurements.Keywords: electrical resistivity, clayey soil, physical properties, shear properties
Procedia PDF Downloads 2701274 Model Updating Based on Modal Parameters Using Hybrid Pattern Search Technique
Authors: N. Guo, C. Xu, Z. C. Yang
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In order to ensure the high reliability of an aircraft, the accurate structural dynamics analysis has become an indispensable part in the design of an aircraft structure. Therefore, the structural finite element model which can be used to accurately calculate the structural dynamics and their transfer relations is the prerequisite in structural dynamic design. A dynamic finite element model updating method is presented to correct the uncertain parameters of the finite element model of a structure using measured modal parameters. The coordinate modal assurance criterion is used to evaluate the correlation level at each coordinate over the experimental and the analytical mode shapes. Then, the weighted summation of the natural frequency residual and the coordinate modal assurance criterion residual is used as the objective function. Moreover, the hybrid pattern search (HPS) optimization technique, which synthesizes the advantages of pattern search (PS) optimization technique and genetic algorithm (GA), is introduced to solve the dynamic FE model updating problem. A numerical simulation and a model updating experiment for GARTEUR aircraft model are performed to validate the feasibility and effectiveness of the present dynamic model updating method, respectively. The updated results show that the proposed method can be successfully used to modify the incorrect parameters with good robustness.Keywords: model updating, modal parameter, coordinate modal assurance criterion, hybrid genetic/pattern search
Procedia PDF Downloads 1501273 An Enhanced SAR-Based Tsunami Detection System
Authors: Jean-Pierre Dubois, Jihad S. Daba, H. Karam, J. Abdallah
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Tsunami early detection and warning systems have proved to be of ultimate importance, especially after the destructive tsunami that hit Japan in March 2012. Such systems are crucial to inform the authorities of any risk of a tsunami and of the degree of its danger in order to make the right decision and notify the public of the actions they need to take to save their lives. The purpose of this research is to enhance existing tsunami detection and warning systems. We first propose an automated and miniaturized model of an early tsunami detection and warning system. The model for the operation of a tsunami warning system is simulated using the data acquisition toolbox of Matlab and measurements acquired from specified internet pages due to the lack of the required real-life sensors, both seismic and hydrologic, and building a graphical user interface for the system. In the second phase of this work, we implement various satellite image filtering schemes to enhance the acquired synthetic aperture radar images of the tsunami affected region that are masked by speckle noise. This enables us to conduct a post-tsunami damage extent study and calculate the percentage damage. We conclude by proposing improvements to the existing telecommunication infrastructure of existing warning tsunami systems using a migration to IP-based networks and fiber optics links.Keywords: detection, GIS, GSN, GTS, GPS, speckle noise, synthetic aperture radar, tsunami, wiener filter
Procedia PDF Downloads 3821272 Strengthening Evaluation of Steel Girder Bridge under Load Rating Analysis: Case Study
Authors: Qudama Albu-Jasim, Majdi Kanaan
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A case study about the load rating and strengthening evaluation of the six-span of steel girders bridge in Colton city of State of California is investigated. To simulate the load rating strengthening assessment for the Colton Overhead bridge, a three-dimensional finite element model built in the CSiBridge program is simulated. Three-dimensional finite-element models of the bridge are established considering the nonlinear behavior of critical bridge components to determine the feasibility and strengthening capacity under load rating analysis. The bridge was evaluated according to Caltrans Bridge Load Rating Manual 1st edition for rating the superstructure using the Load and Resistance Factor Rating (LRFR) method. The analysis for the bridge was based on load rating to determine the largest loads that can be safely placed on existing I-girder steel members and permitted to pass over the bridge. Through extensive numerical simulations, the bridge is identified to be deficient in flexural and shear capacities, and therefore strengthening for reducing the risk is needed. An in-depth parametric study is considered to evaluate the sensitivity of the bridge’s load rating response to variations in its structural parameters. The parametric analysis has exhibited that uncertainties associated with the steel’s yield strength, the superstructure’s weight, and the diaphragm configurations should be considered during the fragility analysis of the bridge system.Keywords: load rating, CSIBridge, strengthening, uncertainties, case study
Procedia PDF Downloads 2051271 The Impact of Public Open Space System on Housing Price in Chicago
Authors: Si Chen, Le Zhang, Xian He
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The research explored the influences of public open space system on housing price through hedonic models, in order to support better open space plans and economic policies. We have three initial hypotheses: 1) public open space system has an overall positive influence on surrounding housing prices. 2) Different public open space types have different levels of influence on motivating surrounding housing prices. 3) Walking and driving accessibilities from property to public open spaces have different statistical relation with housing prices. Cook County, Illinois, was chosen to be a study area since data availability, sufficient open space types, and long-term open space preservation strategies. We considered the housing attributes, driving and walking accessibility scores from houses to nearby public open spaces, and driving accessibility scores to hospitals as influential features and used real housing sales price in 2010 as a dependent variable in the built hedonic model. Through ordinary least squares (OLS) regression analysis, General Moran’s I analysis and geographically weighted regression analysis, we observed the statistical relations between public open spaces and housing sale prices in the three built hedonic models and confirmed all three hypotheses.Keywords: hedonic model, public open space, housing sale price, regression analysis, accessibility score
Procedia PDF Downloads 1241270 The Research Experiences of Supervisors and Postgraduate Research Students at One South African Higher Education Institution
Authors: Madoda Cekiso, Thenjiwe Meyiwa
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Successful postgraduate supervision involves possessing research capabilities, being knowledgeable in specific disciplines, understanding interpersonal relations, exercising mentoring/guidance skills and having appropriate knowledge of own institutional regulatory systems for postgraduate studies. On the other hand, postgraduate students are expected to know what the postgraduate journey entails and the elements and requirements of a postgraduate study. This paper sought to explore and analyse the research experiences of supervisors and postgraduate research students at one South African higher education institution. The study was qualitative in nature and a case study design was followed. The sample was purposively selected and comprised 25 postgraduate students and 20 postgraduate supervisors from one Faculty of the said university. The study findings revealed that there was no clear contract or memorandum of understanding between the postgraduate students and their supervisors. As a result, both supervisors and postgraduate students were not aware of their responsibilities. Both supervisors and postgraduate students complained about the non-availability of postgraduate facilities and resources for postgraduate students. The results further revealed that the allocation of students to supervisors who are not experts in a particular field was a challenge for both postgraduate students and supervisors. The results also revealed that the supervisors were not happy about the commitment of the postgraduate students towards their studies. The supervisors also complained about the postgraduate students who cannot work independently. Based on the findings, the authors recommended that a memorandum of understanding between a postgraduate student and a supervisor might solve some of the challenges. We further recommended a match between the supervisor’s expertise and the student’s focus area.Keywords: feedback, mentoring, postgraduate, supervisors, student, memorandum of understanding
Procedia PDF Downloads 1821269 Relations between Psychological Adjustment and Perceived Parental, Teacher and Best Friend Acceptance among Bangladeshi Adolescents
Authors: Tariqul Islam, Shaheen Mollah
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The study's main objective is to assess the relationship between psychological adjustment and parental acceptance-rejection, teacher acceptance-rejection, and best friend acceptance-rejection among secondary school students. This study was conducted on a sample of 300 (6th through 10th-grade students) recruited from over ten schools in Dhaka. While the schools were selected purposively, the respondents within each school were selected conveniently. The collected data were analyzed using Pearson product-moment correlation, hierarchical regression, and simultaneous regression analysis. The results showed that psychological adjustment is positively correlated with paternal, maternal, teacher, and best friend acceptance. The paternal acceptance was significantly connected with maternal acceptance. The teacher and best friend acceptance are correlated substantially with paternal and maternal acceptance. The hierarchical multiple regressions indicated that maternal, paternal, teacher, and best friend acceptance-rejection contributed significantly to students' psychological adjustment. The results revealed substantial independent contributions of maternal, paternal, teacher, and best friend acceptance on the students' psychological adjustment. The simultaneous regression analysis indicates that the maternal and best friend acceptances (but not paternal acceptance) were significant predictors of psychological adjustments. It showed that 41.7% variability in psychological adjustment could be explained by paternal, maternal, and best friend acceptance. The findings of the present study are exciting. They may contribute to developing insight in parents and best friends for behaving properly with their offspring and friend, respectively, for better psychological adjustment.Keywords: adjustment, parenting, rejection, acceptance
Procedia PDF Downloads 1371268 Application of the Total Least Squares Estimation Method for an Aircraft Aerodynamic Model Identification
Authors: Zaouche Mohamed, Amini Mohamed, Foughali Khaled, Aitkaid Souhila, Bouchiha Nihad Sarah
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The aerodynamic coefficients are important in the evaluation of an aircraft performance and stability-control characteristics. These coefficients also can be used in the automatic flight control systems and mathematical model of flight simulator. The study of the aerodynamic aspect of flying systems is a reserved domain and inaccessible for the developers. Doing tests in a wind tunnel to extract aerodynamic forces and moments requires a specific and expensive means. Besides, the glaring lack of published documentation in this field of study makes the aerodynamic coefficients determination complicated. This work is devoted to the identification of an aerodynamic model, by using an aircraft in virtual simulated environment. We deal with the identification of the system, we present an environment framework based on Software In the Loop (SIL) methodology and we use MicrosoftTM Flight Simulator (FS-2004) as the environment for plane simulation. We propose The Total Least Squares Estimation technique (TLSE) to identify the aerodynamic parameters, which are unknown, variable, classified and used in the expression of the piloting law. In this paper, we define each aerodynamic coefficient as the mean of its numerical values. All other variations are considered as modeling uncertainties that will be compensated by the robustness of the piloting control.Keywords: aircraft aerodynamic model, total least squares estimation, piloting the aircraft, robust control, Microsoft Flight Simulator, MQ-1 predator
Procedia PDF Downloads 2781267 Sintering of Functionally Graded WC-TiC-Co Cemented Carbides
Authors: Stella Sten, Peter Hedström, Joakim Odqvist, Susanne Norgren
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Two functionally graded cemented carbide samples have been produced by local addition of Titanium carbide (TiC) to a pressed Tungsten carbide and Cobalt, WC-10 wt% Co, green body prior to sintering, with the aim of creating a gradient in both composition and grain size in the as-sintered component. The two samples differ only by the in-going WC particle size, where one sub-micron and one coarse WC particle size have been chosen for comparison. The produced sintered samples had a gradient, thus a non-homogenous structure. The Titanium (Ti), Cobalt (Co), and Carbon (C) concentration profiles have been investigated using SEM-EDS and WDS; in addition, the Vickers hardness profile has been measured. Moreover, the Ti concentration profile has been simulated using DICTRA software and compared with experimental results. The concentration and hardness profiles show a similar trend for both samples. Ti and C levels decrease, as expected from the area of TiC application, whereas Co increases towards the edge of the samples. The non-homogenous composition affects the number of stable phases and WC grain size evolution. The sample with finer in-going WC grain size shows a shorter gamma (γ) phase zone and a larger difference in WC grain size compared to the coarse-grained sample. Both samples show, independent of the composition, the presence of abnormally large grains.Keywords: cemented carbide, functional gradient material, grain growth, sintering
Procedia PDF Downloads 841266 The Design and Implementation of a Calorimeter for Evaluation of the Thermal Performance of Materials: The Case of Phase Change Materials
Authors: Ebrahim Solgi, Zahra Hamedani, Behrouz Mohammad Kari, Ruwan Fernando, Henry Skates
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The use of thermal energy storage (TES) as part of a passive design strategy can reduce a building’s energy demand. TES materials do this by increasing the lag between energy consumption and energy supply by absorbing, storing and releasing energy in a controlled manner. The increase of lightweight construction in the building industry has made it harder to utilize thermal mass. Consequently, Phase Change Materials (PCMs) are a promising alternative as they can be manufactured in thin layers and used with lightweight construction to store latent heat. This research investigates utilizing PCMs, with the first step being measuring their performance under experimental conditions. To do this requires three components. The first is a calorimeter for measuring indoor thermal conditions, the second is a pyranometer for recording the solar conditions: global, diffuse and direct radiation and the third is a data-logger for recording temperature and humidity for the studied period. This paper reports on the design and implementation of an experimental setup used to measure the thermal characteristics of PCMs as part of a wall construction. The experimental model has been simulated with the software EnergyPlus to create a reliable simulation model that warrants further investigation.Keywords: phase change materials, EnergyPlus, experimental evaluation, night ventilation
Procedia PDF Downloads 2461265 Agony and Agency: Discursive Construction of Barren women in the Bible and Traditional African Society
Authors: Vicky Khasandi-Telewa, Sinfree Makoni
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Barrenness is a fundamentally agonizing condition that leads to identity disruption in its victims. In Africa, women are usually referred to as ‘Mother of X,’ and this causes grief to one who does not have a child to be identified with. This paper is an examination and critical appraisal of the impact of barrenness on the self-perception of women and the underlying power relations in how they are discursively constructed in the Bible and Traditional African Society (TAS). It is an analysis of expressive practices to examine how barrenness is constructed in Christianity and TAS with the aim of understanding the intersecting power systems. We approach this from an integrationism and Critical Discourse Analysis perspective that takes seriously both the radical harassment of barren women and the possibilities offered by the ensuing desperation calling for inclusive reinterpretation. We also seek to understand barren women’s coping mechanisms and suggestions on how best to improve their lives. The purpose of this study is to explain how discursive construction of barrenness affects the fundamental rights and freedoms of women and what linguistic strategies they adopt to navigate through the maze of stigma. It seeks to illustrate a more nuanced complexity of barren women's lives through women's own exegesis of the Biblical accounts of barrenness and their traditions and to explore alternative narratives. We explore the linguistic strategies the barren women employ to communicate their coping with limitations imposed upon their rights by the negative constructions.Keywords: integrationism, critical discourse analysis, barrenness, communication strategies, women rights
Procedia PDF Downloads 591264 Indonesia’s Defense Diplomacy Strength Towards China’s Aggressive Maritime Policy
Authors: Pangihutan Panjaitan, Helda Risman, Devindra Oktaviano
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This research is departed from the security issues generated from China’s unilateral claims in the South China Sea conflict. The diplomacy challenges come from Indonesia’s relations with China as well as with ASEAN-member countries involved in the conflict. It is estimated that the conflict in the South China Sea region will become an endless conflict. Comprehensively, Indonesia is implementing a gradual shift in diplomatic approach in creating positive and constructive ties among Indonesia, China, and ASEAN. In line with the rapid-changing world order, the conventional military approach becomes less significant in today’s modern inter-state interactions. This research is conducted in a qualitative literature review to explain how Indonesia’s recent soft diplomacy approach applied in the South China Sea conflict. This type of diplomacy theoretically assumed as one of the most preferred ways to establish mutual trust and confidence among conflicting parties. Maritime issues found its significance in contemporary foreign policy since the world’s most dynamic region has moved to the archipelagic Asia-Pacific. As mentioned by rationalists, every country, including Indonesia, has surely formulated its own prominent national interest, such as the defense aspect. Finally, this research will provide a deep analysis on Indonesia’s centrality in ASEAN as an effective way to ensure Indonesia’s strategic policy in the region well accommodated.Keywords: soft diplomacy, south China sea, national defense, China
Procedia PDF Downloads 1531263 Design and Modelling of Ge/GaAs Hetero-structure Bipolar Transistor
Authors: Samson Mil'shtein, Dhawal N. Asthana
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The presented heterostructure n-p-n bipolar transistor is comprised of Ge/GaAs heterojunctions consisting of 0.15µm thick emitter and 0.65µm collector junctions. High diffusivity of carriers in GaAs base was major motivation of current design. We avoided grading of the base which is common in heterojunction bipolar transistors, in order to keep the electron diffusivity as high as possible. The electrons injected into the 0.25µm thick p-type GaAs base with not very high doping (1017cm-3). The designed HBT enables cut off frequency on the order of 150GHz. The Ge/GaAs heterojunctions presented in our paper have proved to work better than comparable HBTs having GaAs bases and emitter/collector junctions made, for example, of AlGaAs/GaAs or other III-V compound semiconductors. The difference in lattice constants between Ge and GaAs is less than 2%. Therefore, there is no need of transition layers between Ge emitter and GaAs base. Significant difference in energy gap of these two materials presents new scope for improving performance of the emitter. With the complete structure being modelled and simulated using TCAD SILVACO, the collector/ emitter offset voltage of the device has been limited to a reasonable value of 63 millivolts by the dint of low energy band gap value associated with Ge emitter. The efficiency of the emitter in our HBT is 86%. Use of Germanium in the emitter and collector regions presents new opportunities for integration of this vertical device structure into silicon substrate.Keywords: Germanium, Gallium Arsenide, heterojunction bipolar transistor, high cut-off frequency
Procedia PDF Downloads 4141262 A Low-Cost Dye Solar Cells Based on Ordinary Glass as Substrates
Authors: Sangmo Jon, Ganghyok Kim, Kwanghyok Jong, Ilnam Jo, Hyangsun Kim, Kukhyon Pae, GyeChol Sin
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The back contact dye solar cells (BCDSCs), in which the transparent conductive oxide (TCO) is omitted, have the potential to use intact low-cost general substrates such as glass, metal foil, and papers. Herein, we introduce a facile manufacturing method of a Ti back contact electrode for the BCDSCs. We found that the polylinkers such as poly(butyl titanate) have a strong binding property to make Ti particles connect with one another. A porous Ti film, which consists of Ti particles of ≤10㎛ size connected by a small amount of polylinkers, has an excellent low sheet resistance of 10 ohm sq⁻¹ for an efficient electron collection for DSCs. This Ti back contact electrode can be prepared by using a facile printing method under normal ambient conditions. Conjugating the new back contact electrode technology with the traditional monolithic structure using the carbon counter electrode, we fabricated all TCO-less DSCs. These four-layer structured DSCs consist of a dye-adsorbed nanocrystalline TiO₂ film on a glass substrate, a porous Ti back contact layer, a ZrO₂ spacer layer, and a carbon counter electrode in a layered structure. Under AM 1.5G and 100mWcm⁻² simulated sunlight illumination, the four-layer structured DSCs with N719 dyes and I⁻/I₃⁻ redox electrolytes achieved PCEs up to 5.21%.Keywords: dye solar cells, TCO-less, back contact, printing, porous Ti film
Procedia PDF Downloads 601261 The Effects of the War between Russia and Ukraine on Qatar’s Fossil and Renewable Energy Policies
Authors: Rahmat Hajimineh, Ebrahim Rezaei Rad
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The war between Russia and Ukraine is considered a very important event in international relations, especially after the end of the Cold War, a war that has had wide dimensions since its beginning. Dimensions that, in addition to political issues, have especially affected the world economy and especially the two countries. The most important issue in the field of the economy that was affected by the war between Russia and Ukraine was the issue of energy. Russia is one of the largest producers and suppliers of natural gas for European countries, and 40% of European gas is supplied by Russia. For this reason, it is natural that European countries have problems in this regard. On the other hand, Ukraine is considered the gateway to Europe for Russia regarding the export of natural gas. The war in Ukraine has had severe effects on gas and energy in Europe. From this point of view, European countries are looking to diversify their energy path by switching to renewable energies, and they are also looking at other energy-producing countries like Qatar to meet their energy needs. In this article, we are trying to investigate the impact of the war between Russia and Ukraine on Qatar's policies in the field of fossil and renewable energy. The descriptive-analytical method and the theoretical framework of energy security have been used to review this article. Based on this, the article examines the situation of fossil and renewable energies in Qatar and, on the other hand, the effects of the war in Ukraine on both energies in Qatar. The findings of this article also indicate that Qatar has made changes in its energy policies after the war in Ukraine, which seems to be possible due to its high potential, especially in the field of renewable and fossil energy. There is an export of surplus production of this country to other countries, especially European countries.Keywords: Ukraine War, fossil fuels, renewable energy, energy security, Qatar
Procedia PDF Downloads 911260 A Data-Mining Model for Protection of FACTS-Based Transmission Line
Authors: Ashok Kalagura
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This paper presents a data-mining model for fault-zone identification of flexible AC transmission systems (FACTS)-based transmission line including a thyristor-controlled series compensator (TCSC) and unified power-flow controller (UPFC), using ensemble decision trees. Given the randomness in the ensemble of decision trees stacked inside the random forests model, it provides an effective decision on the fault-zone identification. Half-cycle post-fault current and voltage samples from the fault inception are used as an input vector against target output ‘1’ for the fault after TCSC/UPFC and ‘1’ for the fault before TCSC/UPFC for fault-zone identification. The algorithm is tested on simulated fault data with wide variations in operating parameters of the power system network, including noisy environment providing a reliability measure of 99% with faster response time (3/4th cycle from fault inception). The results of the presented approach using the RF model indicate the reliable identification of the fault zone in FACTS-based transmission lines.Keywords: distance relaying, fault-zone identification, random forests, RFs, support vector machine, SVM, thyristor-controlled series compensator, TCSC, unified power-flow controller, UPFC
Procedia PDF Downloads 4181259 Effect of Birks Constant and Defocusing Parameter on Triple-to-Double Coincidence Ratio Parameter in Monte Carlo Simulation-GEANT4
Authors: Farmesk Abubaker, Francesco Tortorici, Marco Capogni, Concetta Sutera, Vincenzo Bellini
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This project concerns with the detection efficiency of the portable triple-to-double coincidence ratio (TDCR) at the National Institute of Metrology of Ionizing Radiation (INMRI-ENEA) which allows direct activity measurement and radionuclide standardization for pure-beta emitter or pure electron capture radionuclides. The dependency of the simulated detection efficiency of the TDCR, by using Monte Carlo simulation Geant4 code, on the Birks factor (kB) and defocusing parameter has been examined especially for low energy beta-emitter radionuclides such as 3H and 14C, for which this dependency is relevant. The results achieved in this analysis can be used for selecting the best kB factor and the defocusing parameter for computing theoretical TDCR parameter value. The theoretical results were compared with the available ones, measured by the ENEA TDCR portable detector, for some pure-beta emitter radionuclides. This analysis allowed to improve the knowledge of the characteristics of the ENEA TDCR detector that can be used as a traveling instrument for in-situ measurements with particular benefits in many applications in the field of nuclear medicine and in the nuclear energy industry.Keywords: Birks constant, defocusing parameter, GEANT4 code, TDCR parameter
Procedia PDF Downloads 1401258 Effect of the pH on the Degradation Kinetics of Biodegradable Mg-0.8Ca Orthopedic Implants
Authors: A. Mohamed, A. El-Aziz
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The pH of the body plays a great role in the degradation kinetics of biodegradable Mg-Ca orthopedic implants. At the location of fracture, the pH of the body becomes no longer neutral which draws the attention towards studying a range of different pH values of the body fluid. In this study, the pH of Hank’s balanced salt solution (HBSS) was modified by phosphate buffers into an aggressive acidic pH 1.8, a slightly acidic pH 5.3 and an alkaline pH 8.1. The biodegradation of Mg-0.8Ca implant was tested in those three different media using immersion test and electrochemical polarization means. It was proposed that the degradation rate has increased with decreasing the pH of HBSS. The immersion test revealed weight gain for all the samples followed by weight loss as the immersion time increased. The highest weight gain was pronounced for the acidic pH 1.8 and the least weight gain was observed for the alkaline pH 8.1. This was in agreement with the electrochemical polarization test results where the degradation rate was found to be high (7.29 ± 2.2 mm/year) in the aggressive acidic solution of pH 1.8 and relatively minimum (0.31 ± 0.06 mm/year) in the alkaline medium of pH 8.1. Furthermore, it was confirmed that the pH of HBSS has reached a steady state of an alkaline pH (~pH 11) at the end of the two-month immersion period regardless of the initial pH of the solution. Finally, the corrosion products formed on the samples’ surface were investigated by SEM, EDX and XRD analyses that revealed the formation of magnesium and calcium phosphates with different morphologies according to the pH.Keywords: biodegradable, electrochemical polarization means, orthopedics, immersion test, simulated body fluid
Procedia PDF Downloads 1161257 Collective Behavior of Mice Passing through a Middle-Exit or Corner-Exit under Panic
Authors: Teng Zhang, Xuelin Zhang, Shouxiang Lu, Changhai Li
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The existence of animal groups and collective migration are common in nature, and collective behavior is attracting more and more attention of researchers. Previous results have shown that architectural design had an important effect on the process of crowd evacuation. In this paper, collective behavior of mice passing through a middle-exit or corner-exit under panic was investigated. Selfish behavior and herd behavior were easily observed in our video, which caused the congregation with high density near the exit. Triangle structure of congregation formed near the middle-exit while arch structure formed near the corner-exit. It is noteworthy that the exit located at the middle of the wall was more effective for evacuation than at the corner. Meanwhile, the escape sequence of mouse passing through the exit was investigated, and the result showed that the priority depends largely on its location in the congregation. With the level of stimulus increasing, these phenomena still exist. The frequency distributions of time intervals and the burst sizes were also analyzed in this study to explore the secret of collective behavior of mice. These results could provide evidence for the hypothesis or prediction about human behavior in crowd evacuation. However, it is not clear whether the simulated results from different species can correspond to reality or not. Broader comparison among different species about this topic will be eager to be conducted to deepen our understanding of collective behavior in nature.Keywords: collective behavior, mice, evacuation, exit location
Procedia PDF Downloads 2961256 Finite Element Modelling of a 3D Woven Composite for Automotive Applications
Authors: Ahmad R. Zamani, Luigi Sanguigno, Angelo R. Maligno
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A 3D woven composite, designed for automotive applications, is studied using Abaqus Finite Element (FE) software suite. Python scripts were developed to build FE models of the woven composite in Complete Abaqus Environment (CAE). They can read TexGen or WiseTex files and automatically generate consistent meshes of the fabric and the matrix. A user menu is provided to help define parameters for the FE models, such as type and size of the elements in fabric and matrix as well as the type of matrix-fabric interaction. Node-to-node constraints were imposed to guarantee periodicity of the deformed shapes at the boundaries of the representative volume element of the composite. Tensile loads in three axes and biaxial loads in x-y directions have been applied at different Fibre Volume Fractions (FVFs). A simple damage model was implemented via an Abaqus user material (UMAT) subroutine. Existing tools for homogenization were also used, including voxel mesh generation from TexGen as well as Abaqus Micromechanics plugin. Linear relations between homogenised elastic properties and the FVFs are given. The FE models of composite exhibited balanced behaviour with respect to warp and weft directions in terms of both stiffness and strength.Keywords: 3D woven composite (3DWC), meso-scale finite element model, homogenisation of elastic material properties, Abaqus Python scripting
Procedia PDF Downloads 1301255 Numerical Study of Wettability on the Triangular Micro-pillared Surfaces Using Lattice Boltzmann Method
Authors: Ganesh Meshram, Gloria Biswal
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In this study, we present the numerical investigation of surface wettability on triangular micropillar surfaces by using a two-dimensional (2D) pseudo-potential multiphase lattice Boltzmann method with a D2Q9 model for various interaction parameters of the range varies from -1.40 to -2.50. Initially, simulation of the equilibrium state of a water droplet on a flat surface is considered for various interaction parameters to examine the accuracy of the present numerical model. We then imposed the microscale pillars on the bottom wall of the surface with different heights of the pillars to form the hydrophobic and superhydrophobic surfaces which enable the higher contact angle. The wettability of surfaces is simulated with water droplets of radius 100 lattice units in the domain of 800x800 lattice units. The present study shows that increasing the interaction parameter of the pillared hydrophobic surfaces dramatically reduces the contact area between water droplets and solid walls due to the momentum redirection phenomenon. Contact angles for different values of interaction strength have been validated qualitatively with the analytical results.Keywords: contact angle, lattice boltzmann method, d2q9 model, pseudo-potential multiphase method, hydrophobic surfaces, wenzel state, cassie-baxter state, wettability
Procedia PDF Downloads 63