Search results for: A recurrent neural network for solving nonlinear convex programs subject to linear constraints. IEEE Transactions on Neural Networks
3137 Impact of International Student Mobility on European and Global Identity: A Case Study of Switzerland
Authors: Karina Oborune
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International student mobility involves a unique spatio-temporal context and exploring the various aspects of mobile students’ experience can lead to new findings within identity studies. The previous studies have mainly focused on student mobility within Europe and its impact on European identity arguing that students who participate in intra-European mobility already feel European before exchange. Contrary to previous studies, in this paper student mobility is analyzed from different point of view. In order to see whether a true Europeanization of identities is taking place, it is necessary to contrast European identity with alternative supranational identity which could similarly result from student mobility and in particular a global identity. Besides, in the paper there is explored whether geographical constellation (host country continental location during mobility- Europe vs. outside of Europe) plays a role. Based on newly developed model of multicultural, social and socio-demographic variables there is argued that after intra-European mobility only global identity of students could be increased (H1), but the mobility to countries outside of Europe causes changes in European identity (H2). The quantitative study (survey, n=1440, 22 higher education institutions, experimental group of former and future/potential mobile students and control group of non-mobile students) was held in Switzerland where is equally high number of students who participate in intra-European and outside of Europe mobility. The results of multivariate linear regression showed that students who participate in exchange in Europe increase their European identity due to having close friends from Europe, as well as due to length of the mobility experience had impact, but students who participate in exchange outside of Europe increase their global identity due to having close friends from outside of Europe and proficiency in foreign languages.Keywords: student mobility, European identity, global identity, global identity
Procedia PDF Downloads 7283136 Geopolymerization Methods for Clay Soils Treatment
Authors: Baba Hassane Ahmed Hisseini, Abdelkrim Bennabi, Rabah Hamzaoui, Lamis Makki, Gaetan Blanck
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Most of the clay soils are known as problematic soils due to their water content, which varies greatly over time. It is observed that they are used to be subject to shrinkage and swelling, thus causing a problem of stability on the structures of civil engineering construction work. They are often excavated and placed in a storage area giving rise to the opening of new quarries. This method has become obsolete today because to protect the environment, we are leading to think differently and opening the way to new research for the improvement of the performance of this type of clay soils to reuse them in the construction field. The solidification and stabilization technique is used to improve the properties of poor quality soils to transform them into materials with a suitable performance for a new use in the civil engineering field rather than to excavate them and store them in the discharge area. In our case, the polymerization method is used for bad clay soils classified as high plasticity soil class A4 according to the French standard NF P11-300, where classical treatment methods with cement or lime are not efficient. Our work concerns clay soil treatment study using raw materials as additives for solidification and stabilization. The geopolymers are synthesized by aluminosilicates materials like fly ash, metakaolin, or blast furnace slag and activated by alkaline solution based on sodium hydroxide (NaOH), sodium silicate (Na2SiO3) or a mixture of both of them. In this study, we present the mechanical properties of the soil clay (A4 type) evolution with geopolymerisation methods treatment. Various mix design of aluminosilicates materials and alkaline solutions were carried at different percentages and different curing times of 1, 7, and 28 days. The compressive strength of the untreated clayey soil could be increased from simple to triple. It is observed that the improvement of compressive strength is associated with a geopolymerization mechanism. The highest compressive strength was found with metakaolin at 28 days.Keywords: treatment and valorization of clay-soil, solidification and stabilization, alkali-activation of co-product, geopolymerization
Procedia PDF Downloads 1603135 Accuracy Improvement of Traffic Participant Classification Using Millimeter-Wave Radar by Leveraging Simulator Based on Domain Adaptation
Authors: Tokihiko Akita, Seiichi Mita
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A millimeter-wave radar is the most robust against adverse environments, making it an essential environment recognition sensor for automated driving. However, the reflection signal is sparse and unstable, so it is difficult to obtain the high recognition accuracy. Deep learning provides high accuracy even for them in recognition, but requires large scale datasets with ground truth. Specially, it takes a lot of cost to annotate for a millimeter-wave radar. For the solution, utilizing a simulator that can generate an annotated huge dataset is effective. Simulation of the radar is more difficult to match with real world data than camera image, and recognition by deep learning with higher-order features using the simulator causes further deviation. We have challenged to improve the accuracy of traffic participant classification by fusing simulator and real-world data with domain adaptation technique. Experimental results with the domain adaptation network created by us show that classification accuracy can be improved even with a few real-world data.Keywords: millimeter-wave radar, object classification, deep learning, simulation, domain adaptation
Procedia PDF Downloads 913134 Turkey in Minds: Cognitive and Social Representation of "East" and "West"
Authors: Feyzan Tuzkaya, Nihan S. Soylu, Caglar Solak, Mehmet Peker, Hilal Peker, Kemal Ozeralp, Ceren Mete, Ezgi Mehmetoglu, Mehmet Karasu, Cihan Elci, Ece Akca, Melek Goregenli
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Perception, evaluation and representation of the environment have been the subject of many disciplines including psychology, geography and architecture. In environmental and social psychology literature there are several evidences which suggest that cognitive representations about a place consisted of not only geographic items but also social and cultural. Mental representations of residence area or a country is influenced and determined by social-demographics, the physical and social context. Thus, all mental representations of a given place are also social representations. Cognitive maps are the main and common instruments that are used to identify spatial images and the difference between physical and subjective environments. The aim of the current study is investigating the mental and social representations of Turkey in university students’ minds. Data was collected from 249 university students from different departments (i.e. psychology, geography, history, tourism departments) of Ege University. Participants were requested to reflect Turkey in their mind onto the paper drawing sketch maps. According to the results, cognitive maps showed geographic aspects of Turkey as well as the context of symbolic, cultural and political reality of Turkey. That is to say, these maps had many symbolic and verbal items related to critics on social and cultural problems, ongoing ethnic and political conflicts, and actual political agenda of Turkey. Additionally, one of main differentiations in these representations appeared in terms of the East and West side of the Turkey, and the representations of the East and West was varied correspondingly participants’ cultural background, their ethnic values, and where they have born. The results of the study were discussed in environmental and social psychological perspective considering cultural and social values of Turkey and current political circumstances of the country.Keywords: cognitive maps, East, West, politics, social representations, Turkey
Procedia PDF Downloads 4083133 Callous-Unemotional Traits in Preschoolers: Distinct Associations with Empathy Subcomponents
Authors: E. Stylianopoulou, A. K. Fanti
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Object: Children scoring high on Callous-Unemotional traits (CU traits) exhibit lack of empathy. More specifically, children scoring high on CU traits appear to exhibit deficits on affective empathy or deficits in other constructs. However, little is known about cognitive empathy, and it's relation with CU traits in preschoolers. Despite the fact that empathy is measurable at a very young age, relatively less study has focused on empathy in preschoolers than older children with CU traits. The present study examines the cognitive and affective empathy in preschoolers with CU traits. The aim was to examine the differences between cognitive and affective empathy in those individuals. Based on previous research in children with CU traits, it was hypothesized that preschoolers scoring high in CU traits will show deficits in both cognitive and affective empathy; however, more deficits will be detected in affective empathy rather than cognitive empathy. Method: The sample size was 209 children, of which 109 were male, and 100 were female between the ages of 3 and 7 (M=4.73, SD=0.71). From those participants, only 175 completed all the items. The Inventory of Callous-Unemotional traits was used to measure CU traits. Moreover, the Griffith Empathy Measure (GEM) Affective Scale and the Griffith Empathy Measure (GEM) Cognitive Scale was used to measure Affective and Cognitive empathy, respectively. Results: Linear Regression was applied to examine the preceding hypotheses. The results showed that generally, there was a moderate negative association between CU traits and empathy, which was significant. More specifically, it has been found that there was a significant and negative moderate relation between CU traits and cognitive empathy. Surprisingly, results indicated that there was no significant relation between CU traits and affective empathy. Conclusion: The current findings support that preschoolers show deficits in understanding others emotions, indicating a significant association between CU traits and cognitive empathy. However, such a relation was not found between CU traits and affective empathy. The current results raised the importance that there is a need for focusing more on cognitive empathy in preschoolers with CU traits, a component that seems to be underestimated till now.Keywords: affective empathy, callous-unemotional traits, cognitive empathy, preschoolers
Procedia PDF Downloads 1493132 The Meaning of Stillness: Based on the Errand Boy Project in Tibet during the Pandemic Quarantine in Shanghai in the Mayday Holiday
Authors: Mingyuan Duan
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Many scholars have paid attention to the relationship between mobility and stillness, but most of them focus on stillness from the perspective of serving mobility. This study believes that more attention should be paid to the importance of stillness, and we suggest reexamining the meaning of stillness in terms of the value of stillness to people. The Errand Boy Project was launched by a social innovation enterprise called Bottle Dream during the May Day holiday in 2022. It linked volunteers from all over the world online to help people who are trapped at home due to the epidemic realize their outdoor wishes: get closer to nature and relieve their anxious mood. Taking Errand Boy in Tibet as a case study, this paper analyzes the emotional expressions and comments of people with limited mobility in the face of nature in the webcast room and explains the importance of stillness to humans from a non-human perspective. This study points out that the significance of stillness to human beings during the pandemic is composed of three aspects: the sense of solidity established by a steady mobile phone network connection, the stable possibility of wish fulfillment predicted by the periodic regularity of plant growth, and the transcendent spiritual power from the stable sacred mountain.Keywords: stillness, non-human, pandemic, mobility
Procedia PDF Downloads 733131 Pedagogical Agency: A Basic Capacity to Carry out a Humanizing and Democratic Pedagog
Authors: Priscilla Echeverria
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For us grown up in neoliberal societies, it is not always clear that we have not only incorporated an economic logic into our subjectivities, but a technical reason, an instrumental way of relationship with the environment inspired in a control interest that constantly dehumanizes us as takes away our capacity of action, becoming mere objects or bureaucrats, stripped of our citizen dimension to participate in social and political issues responsibly and creatively. To restore the capacity of action -agency- is urgent in our societies to strengthen better democracies. On this, the formal educational system plays a crucial role, which in turn needs teachers prepared to understand their role as integral educators instead of mere curriculum managers. For this reason, initial teacher formation (ITF) programs must assume the responsibility of helping them to develop an ethical/political/epistemic pedagogical agency to deal with a technical school culture and, in turn, able to relate to their students in democratic ways to help them to develop their agency capacities. By highlighting a perspective of education as the opposite of technocracy and bureaucracy, this talk precisely addresses ITF as a crucial and formative space to restore a perspective of what a critical education can look like, enabling pedagogy students with pedagogical agency capacities to, in turn, allow their future students to develop it. This discussion is part of my doctoral research, "The importance of developing the capacity for ethical-political-epistemic agency in novice teachers during initial teacher formation to contribute to social justice", which I currently develop in the Educational Research program of the University of Lancaster, United Kingdom, as a Conicyt fellow for the 2019 cohort. This presentation specifically offers preliminary results of the analysis of critical incidents as a research methodological tool to analyse the capacity of pedagogical agency deployed by novice teachers in their first pedagogical experiences in the Chilean context.Keywords: initial teacher formation, pedagogical agency, pedagogical interaction, hidden curriculum, critical pedagogy, social justice
Procedia PDF Downloads 1113130 Online Consortium of Independent Colleges and Universities (OCICU): Using Cluster Analysis to Grasp Student and Institutional Value of Consolidated Online Offerings in Higher Education
Authors: Alex Rodriguez, Adam Guerrero
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Purpose: This study is designed to examine the institutions that comprise the Online Consortium of Independent Colleges and Universities (OCICU) to understand better the types of higher education institutions that comprise their membership. The literature on this topic is extensive in analyzing the current economic environment around higher education, which is largely considered to be negative for independent, tuition-driven institutions, and is forcing colleges and universities to reexamine how the college-attending population defines value and how institutions can best utilize their existing resources (and those of other institutions) to meet that value expectation. The results from this analysis are intended to give OCICU the ability to target their current customer base better, based on their most notable differences, and other institutions to see how to best approach consolidation within higher education. Design/Methodology: This study utilized k-means cluster analysis in order to explore the possibility that different segments exist within the seventy-one colleges and universities that have comprised OCICU. It analyzed fifty different variables, whose selection was based on the previous literature, collected by the Integrated Postsecondary Education Data System (IPEDS), whose data is self-reported by individual institutions. Findings: OCICU member institutions are partitioned into two clusters: "access institutions" and "conventional institutions” based largely on the student profile they target. Value: The methodology of the study is relatively unique as there are not many studies within the field of higher education marketing that have employed cluster analysis, and this type of analysis has never been conducted on OCICU members, specifically, or that of any higher education consolidated offering. OCICU can use the findings of this study to obtain a better grasp as to the specific needs of the two market segments OCICU currently serves and develop measurable marketing programs around how those segments are defined that communicate the value sought by current and potential OCICU members or those of similar institutions. Other consolidation efforts within higher education can also employ the same methodology to determine their own market segments.Keywords: Consolidation, Colleges, Enrollment, Higher Education, Marketing, Strategy, Universities
Procedia PDF Downloads 1333129 Preparation and Characterization of Transparent and Conductive SnO2 Thin Films by Spray Pyrolysis
Authors: V. Jelev, P. Petkov, P. Shindov
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Thin films of undoped and As-doped tin oxide (As:SnO2) were obtained on silicon and glass substrates at 450°- 480°C by spray pyrolysis technique. Tin chloride (SnCl4.5H2O) and As oxide (3As2O5.5H2O) were used as a source for Sn and As respectively. The As2O5 concentration was varied from 0 to 10 mol% in the starting water-alcoholic solution. The characterization of the films was provided with XRD, CEM, AFM and UV-VIS spectroscopy. The influence of the synthesis parameters (the temperature of the substrate, solution concentration, gas and solution flow rates, deposition time, nozzle-to substrate distance) on the optical, electrical and structural properties of the films was investigated. The substrate temperature influences on the surface topography, structure and resistivity of the films. Films grown at low temperatures (<300°C) are amorphous whereas this deposited at higher temperatures have certain degree of polycrystallinity. Thin oxide films deposited at 450°C are generally polycrystalline with tetragonal rutile structure. The resistivity decreases with dopant concentration. The minimum resistivity was achieved at dopant concentration about 2.5 mol% As2O5 in the solution. The transmittance greater than 80% and resistivity smaller than 7.5.10-4Ω.cm were achieved in the films deposited at 480°C. The As doped films (SnO2: As) deposited on silicon substrates was used for preparation of a large area position sensitive photodetector (PSD), acting on the base of a lateral photovoltaic effect. The position characteristic of PSD is symmetric to the zero and linear in the 80% of the active area. The SnO2 films are extremely stable under typical environmental conditions and extremely resistant to chemical etching.Keywords: metal oxide film, SnO2 film, position sensitive photodetectors (PSD), lateral photovoltaic effect
Procedia PDF Downloads 3003128 Examining Terrorism through a Constructivist Framework: Case Study of the Islamic State
Authors: Shivani Yadav
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The Study of terrorism lends itself to the constructivist framework as constructivism focuses on the importance of ideas and norms in shaping interests and identities. Constructivism is pertinent to understand the phenomenon of a terrorist organization like the Islamic State (IS), which opportunistically utilizes radical ideas and norms to shape its ‘politics of identity’. This ‘identity’, which is at the helm of preferences and interests of actors, in turn, shapes actions. The paper argues that an effective counter-terrorism policy must recognize the importance of ideas in order to counter the threat arising from acts of radicalism and terrorism. Traditional theories of international relations, with an emphasis on state-centric security problematic, exhibit several limitations and problems in interpreting the phenomena of terrorism. With the changing global order, these theories have failed to adapt to the changing dimensions of terrorism, especially ‘newer’ actors like the Islamic State (IS). The paper observes that IS distinguishes itself from other terrorist organizations in the way that it recruits and spreads its propaganda. Not only are its methods different, but also its tools (like social media) are new. Traditionally, too, force alone has rarely been sufficient to counter terrorism, but it seems especially impossible to completely root out an organization like IS. Time is ripe to change the discourse around terrorism and counter-terrorism strategies. The counter-terrorism measures adopted by states, which primarily focus on mitigating threats to the national security of the state, are preoccupied with statist objectives of the continuance of state institutions and maintenance of order. This limitation prevents these theories from addressing the questions of justice and the ‘human’ aspects of ideas and identity. These counter-terrorism strategies adopt a problem-solving approach that attempts to treat the symptoms without diagnosing the disease. Hence, these restrictive strategies fail to look beyond calculated retaliation against violent actions in order to address the underlying causes of discontent pertaining to ‘why’ actors turn violent in the first place. What traditional theories also overlook is that overt acts of violence may have several causal factors behind them, some of which are rooted in the structural state system. Exploring these root causes through the constructivist framework helps to decipher the process of ‘construction of terror’ and to move beyond the ‘what’ in theorization in order to describe ‘why’, ‘how’ and ‘when’ terrorism occurs. Study of terrorism would much benefit from a constructivist analysis in order to explore non-military options while countering the ideology propagated by the IS.Keywords: constructivism, counter terrorism, Islamic State, politics of identity
Procedia PDF Downloads 1863127 Correlation Between Diastolic Function and Lower GLS in Hypertensive Patients
Authors: A. Kherraf, S. Ouarrak, L. Azzouzi, R. Habbal
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Introduction: Preserved LVEF heart failure is an important cause of mortality and morbidity in hypertensive patients. A strong correlation between impaired diastolic function and longitudinal systolic dysfunction. could have several explanations, first, the diastole is an energy dependent process, especially during its first phase, it also includes active systolic components during the phase of iso volumetric relaxation, in addition, the impairment of the intrinsic myocytic function is part of hypertensive pathology as evidenced by recent studies. METHODS AND MATERIALS: This work consists of performing in a series of 333 hypertensive patients (aged 25 to 75 years) a complete echocardiographic study, including LVEF by Simpson biplane method, the calculation of the indexed left ventricular mass, the analysis of the diastolic function, and finally, the study of the longitudinal deformation of the LV by the technique of speckletracking (calculation of the GLS). Patients with secondary hypertension, leaky or stenosing valve disease, arrhythmia, and a history of coronary insufficiency were excluded from this study. RESULTS: Of the 333 hypertensive patients, 225 patients (67.5%) had impaired diastolic function, of which 60 patients (18%) had high filling pressures. 49.39% had echocardigraphic HVG, Almost all of these patients (60 patients) had low GLS. There is a statistically very significant relationship between lower GLS and increased left ventricular filling pressures in hypertensive patients. These results suggest that increased filling pressures are closely associated with atrioventricular interaction in patients with hypertension, with a strong correlation with impairment of longitudinal systolic function and diastolic function CONCLUSION: Overall, a linear relationship is established between increased left ventricular mass, diastolic dysfunction, and longitudinal LV systolic dysfunctionKeywords: hypertension, diastolic function, left ventricle, heart failure
Procedia PDF Downloads 1253126 Optimization of Heat Insulation Structure and Heat Flux Calculation Method of Slug Calorimeter
Authors: Zhu Xinxin, Wang Hui, Yang Kai
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Heat flux is one of the most important test parameters in the ground thermal protection test. Slug calorimeter is selected as the main sensor measuring heat flux in arc wind tunnel test due to the convenience and low cost. However, because of excessive lateral heat transfer and the disadvantage of the calculation method, the heat flux measurement error of the slug calorimeter is large. In order to enhance measurement accuracy, the heat insulation structure and heat flux calculation method of slug calorimeter were improved. The heat transfer model of the slug calorimeter was built according to the energy conservation principle. Based on the heat transfer model, the insulating sleeve of the hollow structure was designed, which helped to greatly decrease lateral heat transfer. And the slug with insulating sleeve of hollow structure was encapsulated using a package shell. The improved insulation structure reduced heat loss and ensured that the heat transfer characteristics were almost the same when calibrated and tested. The heat flux calibration test was carried out in arc lamp system for heat flux sensor calibration, and the results show that test accuracy and precision of slug calorimeter are improved greatly. In the meantime, the simulation model of the slug calorimeter was built. The heat flux values in different temperature rise time periods were calculated by the simulation model. The results show that extracting the data of the temperature rise rate as soon as possible can result in a smaller heat flux calculation error. Then the different thermal contact resistance affecting calculation error was analyzed by the simulation model. The contact resistance between the slug and the insulating sleeve was identified as the main influencing factor. The direct comparison calibration correction method was proposed based on only heat flux calibration. The numerical calculation correction method was proposed based on the heat flux calibration and simulation model of slug calorimeter after the simulation model was solved by solving the contact resistance between the slug and the insulating sleeve. The simulation and test results show that two methods can greatly reduce the heat flux measurement error. Finally, the improved slug calorimeter was tested in the arc wind tunnel. And test results show that the repeatability accuracy of improved slug calorimeter is less than 3%. The deviation of measurement value from different slug calorimeters is less than 3% in the same fluid field. The deviation of measurement value between slug calorimeter and Gordon Gage is less than 4% in the same fluid field.Keywords: correction method, heat flux calculation, heat insulation structure, heat transfer model, slug calorimeter
Procedia PDF Downloads 1163125 The Life Skills Project: Client-Centered Approaches to Life Skills Acquisition for Homeless and At-Risk Populations
Authors: Leah Burton, Sara Cumming, Julianne DiSanto
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Homelessness is a widespread and complex problem in Canada and around the globe. Many Canadians will face homelessness at least once in their lifetime, with several experiencing subsequent bouts or cyclical patterns of housing precarity. While a Housing First approach to homelessness is a long-standing and widely accepted best practice, it is also recognized that the acquisition of life skills is an effective way to reduce cycles of homelessness. Indeed, when individuals are provided with a range of life skills—such as (but not limited to) financial literacy, household management, interpersonal skills, critical thinking, and resource management—they are given the tools required to maintain long-term Housing for a lifetime; thus reducing a repetitive need for services. However, there is limited research regarding the best ways to teach life skills, a problem that has been further complicated in a post-pandemic world, where services are being delivered online or in a hybrid model of care. More than this, it is difficult to provide life skills on a large scale without losing a client-centered approach to services. This lack of client-centeredness is also seen in the lack of attention to culturally sensitive life skills, which consider the diverse needs of individuals and imbed equity, diversity, and inclusion (EDI) within the skills being taught. This study aims to fill these identified gaps in the literature by employing a community-engaged (CER) approach. Academic, government, funders, front-line staff, and clients at 15 not-for-profits from across the Greater Toronto Area in Ontario, Canada, collaborated to co-create a virtual, client-centric, EDI-informed life skill learning management system. A triangulation methodology was utilized for this research. An environmental scan was conducted for current best practices, and over 100 front-line staff (including workers, managers, and executive directors who work with homeless populations) participated in two separate Creative Problem Solving Sessions. Over 200 individuals with experience in homelessness completed quantitative and open-ended surveys. All sections of this research aimed to discover the areas of skills that individuals need to maintain Housing and to ascertain what a more client-driven EDI approach to life skills training should include. This presentation will showcase the findings on which life skills are deemed essential for homeless and precariously housed individuals.Keywords: homelessness, housing first, life skills, community engaged research, client- centered
Procedia PDF Downloads 1013124 Examining E-learning Capability in Chinese Higher Education: A Case Study of Hong Kong
Authors: Elson Szeto
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Over the past 15 years, digital technology has ubiquitously penetrated societies around the world. New values of e-learning are emerging in the preparation of future talents, while e-learning is a key driver of widening participation and knowledge transfer in Chinese higher education. As a vibrant, Chinese society in Asia, Hong Kong’s new generation university students, perhaps the digital natives, have been learning with e-learning since their basic education. They can acquire new knowledge with the use of different forms of e-learning as a generic competence. These students who embrace this competence further their study journeys in higher education. This project reviews the Government’s policy of Information Technology in Education which has largely put forward since 1998. So far, primary to secondary education has embraced advantages of e-learning capability to advance the learning of different subject knowledge. Yet, e-learning capacity in higher education is yet to be fully examined in Hong Kong. The study reported in this paper is a pilot investigation into e-learning capacity in Chinese higher education in the region. By conducting a qualitative case study of Hong Kong, the investigation focuses on (1) the institutional ICT settings in general; (2) the pedagogic responses to e-learning in specific; and (3) the university students’ satisfaction of e-learning. It is imperative to revisit the e-learning capacity for promoting effective learning amongst university students, supporting new knowledge acquisition and embracing new opportunities in the 21st century. As a pilot case study, data will be collected from individual interviews with the e-learning management team members of a university, teachers who use e-learning for teaching and students who attend courses comprised of e-learning components. The findings show the e-learning capacity of the university and the key components of leveraging e-learning capability as a university-wide learning settings. The findings will inform institutions’ senior management, enabling them to effectively enhance institutional e-learning capacity for effective learning and teaching and new knowledge acquisition. Policymakers will be aware of new potentials of e-learning for the preparation of future talents in this society at large.Keywords: capability, e-learning, higher education, student learning
Procedia PDF Downloads 2733123 Numerical Analysis for Soil Compaction and Plastic Points Extension in Pile Drivability
Authors: Omid Tavasoli, Mahmoud Ghazavi
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A numerical analysis of drivability of piles in different geometry is presented. In this paper, a three-dimensional finite difference analysis for plastic point extension and soil compaction in the effect of pile driving is analyzed. Four pile configurations such as cylindrical pile, fully tapered pile, T-C pile consists of a top tapered segment and a lower cylindrical segment and C-T pile has a top cylindrical part followed by a tapered part are investigated. All piles which driven up to a total penetration depth of 16 m have the same length with equivalent surface area and approximately with identical material volumes. An idealization for pile-soil system in pile driving is considered for this approach. A linear elastic material is assumed to model the vertical pile behaviors and the soil obeys the elasto-plastic constitutive low and its failure is controlled by the Mohr-Coulomb failure criterion. A slip which occurred at the pile-soil contact surfaces along the shaft and the toe in pile driving procedures is simulated with interface elements. All initial and boundary conditions are the same in all analyses. Quiet boundaries are used to prevent wave reflection in the lateral and vertical directions for the soil. The results obtained from numerical analyses were compared with available other numerical data and laboratory tests, indicating a satisfactory agreement. It will be shown that with increasing the angle of taper, the permanent piles toe settlement increase and therefore, the extension of plastic points increase. These are interesting phenomena in pile driving and are on the safe side for driven piles.Keywords: pile driving, finite difference method, non-uniform piles, pile geometry, pile set, plastic points, soil compaction
Procedia PDF Downloads 4823122 Experimental and Numerical Investigation on the Torque in a Small Gap Taylor-Couette Flow with Smooth and Grooved Surface
Authors: L. Joseph, B. Farid, F. Ravelet
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Fundamental studies were performed on bifurcation, instabilities and turbulence in Taylor-Couette flow and applied to many engineering applications like astrophysics models in the accretion disks, shrouded fans, and electric motors. Such rotating machinery performances need to have a better understanding of the fluid flow distribution to quantify the power losses and the heat transfer distribution. The present investigation is focused on high gap ratio of Taylor-Couette flow with high rotational speeds, for smooth and grooved surfaces. So far, few works has been done in a very narrow gap and with very high rotation rates and, to the best of our knowledge, not with this combination with grooved surface. We study numerically the turbulent flow between two coaxial cylinders where R1 and R2 are the inner and outer radii respectively, where only the inner is rotating. The gap between the rotor and the stator varies between 0.5 and 2 mm, which corresponds to a radius ratio η = R1/R2 between 0.96 and 0.99 and an aspect ratio Γ= L/d between 50 and 200, where L is the length of the rotor and d being the gap between the two cylinders. The scaling of the torque with the Reynolds number is determined at different gaps for different smooth and grooved surfaces (and also with different number of grooves). The fluid in the gap is air. Re varies between 8000 and 30000. Another dimensionless parameter that plays an important role in the distinction of the regime of the flow is the Taylor number that corresponds to the ratio between the centrifugal forces and the viscous forces (from 6.7 X 105 to 4.2 X 107). The torque will be first evaluated with RANS and U-RANS models, and compared to empirical models and experimental results. A mesh convergence study has been done for each rotor-stator combination. The results of the torque are compared to different meshes in 2D dimensions. For the smooth surfaces, the models used overestimate the torque compared to the empirical equations that exist in the bibliography. The closest models to the empirical models are those solving the equations near to the wall. The greatest torque achieved with grooved surface. The tangential velocity in the gap was always higher in between the rotor and the stator and not on the wall of rotor. Also the greater one was in the groove in the recirculation zones. In order to avoid endwall effects, long cylinders are used in our setup (100 mm), torque is measured by a co-rotating torquemeter. The rotor is driven by an air turbine of an automotive turbo-compressor for high angular velocities. The results of the experimental measurements are at rotational speed of up to 50 000 rpm. The first experimental results are in agreement with numerical ones. Currently, quantitative study is performed on grooved surface, to determine the effect of number of grooves on the torque, experimentally and numerically.Keywords: Taylor-Couette flow, high gap ratio, grooved surface, high speed
Procedia PDF Downloads 4063121 Revised Tower Earthing Design in High-Voltage Transmission Network for High-Frequency Lightning Condition
Authors: Azwadi Mohamad, Pauzi Yahaya, Nadiah Hudi
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Earthing system for high-voltage transmission tower is designed to protect the working personnel and equipments, and to maintain the quality of supply during fault. The existing earthing system for transmission towers in TNB’s system is purposely designed for normal power frequency (low-frequency) fault conditions that take into account the step and touch voltages. This earthing design is found to be inapt for lightning (transient) condition to a certain extent, which involves a high-frequency domain. The current earthing practice of laying the electrodes radially in straight 60 m horizontal lines under the ground, in order to achieve the specified impedance value of less than 10 Ω, was deemed ineffective in reducing the high-frequency impedance. This paper introduces a new earthing design that produces low impedance value at the high-frequency domain, without compromising the performance of low-frequency impedance. The performances of this new earthing design, as well as the existing design, are simulated for various soil resistivity values at varying frequency. The proposed concentrated earthing design is found to possess low TFR value at both low and high-frequency. A good earthing design should have a fine balance between compact and radial electrodes under the ground.Keywords: earthing design, high-frequency, lightning, tower footing impedance
Procedia PDF Downloads 1593120 Stress among Mothers of Children with Cerebral Palsy
Authors: Priyanka Tiwari, Uma Devi Ranjit, Ritesh Thapa
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Background and Significance: Cerebral Palsy (CP) influences not only the child's everyday functioning but also the functioning of whole family. Application of study findings can be used in clinical or community setting to screen the parents of children with cerebral palsy in order to identify the compromised domain of stress which in turn will help to improve the interaction between parent and child with disability and thus ultimately affect the progress that a child makes in his or her therapeutic or educational programs. Objective: The objective of the study was to assess the level of stress in mothers of children with CP by adopting mixed method design. Methodology: Cross-sectional descriptive design was adopted in the quantitative design where Parental Stress Scale (PSS) was utilized to collect data from a convenient sample of 40 mothers of children with CP who were under regular follow-up by home visitor of Self-help Group for Cerebral Palsy while embedded qualitative design was used to explore the stress of mothers of CP affected children. From the parent population of quantitative sample 4 mothers were chosen for in-depth exploration, regarding their stress by means of case study method. Descriptive statistics like frequency, percentage, mean, median, standard deviation, correlation and inferential statistics like Mann-Whitney U test and Kruskal-Wallis H test were used to describe and assess relationship between variables. Findings: The mean stress experienced by mothers of children with cerebral palsy was 53.62±9.53 with 15% percent of the mothers experiencing severe stress. There was significant association between age group of mother and total stress score and negative themes of stress. Similarly, signification association was found between educational status of the mother and positive themes of stress which was convergent with the qualitative finding as well, where literate mothers had more positive view of their child's disability which could be attributed to their educational level as education provides us with a broad perspective to look at a situation. Conclusions: Still one-sixth of the mothers experienced severe stress so if we want to ensure the well-being of the children affected by cerebral palsy, then parents caring for them need to be looked after as well.Keywords: stress, cerebral palsy, mothers, mixed method
Procedia PDF Downloads 2583119 Pracademia in Irish Higher Education: The Only Solution to Contemporary Regulation in Professional Social Care Practice
Authors: Aoife Prendergast
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The synergy between theory and practice can be considered elusive, the touchstone for the development of successful undergraduate programmes particularly in allied health professions such as social care. A 'pracademic' is a person who spans both the somewhat ethereal world of academia as a scholar and the pragmatic world of practice. This paper examines the concept of 'pracademia' in relation to the role of the social care practitioner and continuing professional development. It also assists in the understanding of the synergy between social care professionals and higher education. A consideration of the identity and position in terms of approach to regulation is explored as well as an acknowledgement of the strengths and opportunities for sharing power in hierarchical positions. The world of practice serves as the centre point of the academic compass for most professional programs. Just as schools of engineering and law are disciplined by the marketplace, which seeks well-trained students, so our social care programmes must perennially find ways to address the fast changing needs of practitioners, whether they be government, not-for-profit organizations, consulting firms or contractors. We may not expect such traditional academic disciplines as history, sociology, or political science to cater to the needs of external audiences or practitioners— indeed, these disciplines' insulation from public concerns and issues is considered a strength by some. This paper aims to explore the integration of academic teaching and research with the communities of practice in social care. This appears to be a fundamental aspiration of the social care profession. While building and integrating an important body of academic theory and concepts from a variety of disciplines, social care as a field has embraced a professional orientation by seeking to be relevant to practitioners at various levels. While teaching theory, social care programmes, and faculty are often acutely aware that their academic content and credibility, in part, rest on a deep connection with practitioners. While theory can be self-contained, the impact of our research and teaching arguably finds its most compelling and highest audience when it addresses the agenda items and concerns of practitioners.Keywords: social care, pracademia, supervision, practice education
Procedia PDF Downloads 1623118 On the Effect of Carbon on the Efficiency of Titanium as a Hydrogen Storage Material
Authors: Ghazi R. Reda Mahmoud Reda
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Among the metal that forms hydride´s, Mg and Ti are known as the most lightweight materials; however, they are covered with a passive layer of oxides and hydroxides and require activation treatment under high temperature ( > 300 C ) and hydrogen pressure ( > 3 MPa) before being used for storage and transport applications. It is well known that small graphite addition to Ti or Mg, lead to a dramatic change in the kinetics of mechanically induced hydrogen sorption ( uptake) and significantly stimulate the Ti-Hydrogen interaction. Many explanations were given by different authors to explain the effect of graphite addition on the performance of Ti as material for hydrogen storage. Not only graphite but also the addition of a polycyclic aromatic compound will also improve the hydrogen absorption kinetics. It will be shown that the function of carbon addition is two-fold. First carbon acts as a vacuum cleaner, which scavenges out all the interstitial oxygen that can poison or slow down hydrogen absorption. It is also important to note that oxygen favors the chemisorption of hydrogen, which is not desirable for hydrogen storage. Second, during scavenging of the interstitial oxygen, the carbon reacts with oxygen in the nano and microchannel through a highly exothermic reaction to produce carbon dioxide and monoxide which provide the necessary heat for activation and thus in the presence of carbon lower heat of activation for hydrogen absorption which is observed experimentally. Furthermore, the product of the reaction of hydrogen with the carbon oxide will produce water which due to ball milling hydrolyze to produce the linear H5O2 + this will reconstruct the primary structure of the nanocarbon to form secondary structure, where the primary structure (a sheet of carbon) are connected through hydrogen bonding. It is the space between these sheets where physisorption or defect mediated sorption occurs.Keywords: metal forming hydrides, polar molecule impurities, titanium, phase diagram, hydrogen absorption
Procedia PDF Downloads 3603117 Numerical Simulations of Fire in Typical Air Conditioned Railway Coach
Authors: Manoj Sarda, Abhishek Agarwal, Juhi Kaushik, Vatsal Sanjay, Arup Kumar Das
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Railways in India remain primary mode of transport having one of the largest networks in the world and catering to billions of transits yearly. Catastrophic economic damage and loss to life is encountered over the past few decades due to fire to locomotives. Study of fire dynamics and fire propagation plays an important role in evacuation planning and reducing losses. Simulation based study of propagation of fire and soot inside an air conditioned coach of Indian locomotive is done in this paper. Finite difference based solver, Fire Dynamic Simulator (FDS) version 6 has been used for analysis. A single air conditioned 3 tier coupe closed to ambient surroundings by glass windows having occupancy for 8 people is the basic unit of the domain. A system of three such coupes combined is taken to be fundamental unit for the entire study to resemble effect to an entire coach. Analysis of flame and soot contours and concentrations is done corresponding to variations in heat release rate per unit volume (HRRPUA) of fire source, variations in conditioned air velocity being circulated inside coupes by vents and an alternate fire initiation and propagation mechanism via ducts. Quantitative results of fractional area in top and front view of the three coupes under fire and smoke are obtained using MATLAB (IMT). Present simulations and its findings will be useful for organizations like Commission of Railway Safety and others in designing and implementing safety and evacuation measures.Keywords: air conditioned coaches, fire propagation, flame contour, soot flow, train fire
Procedia PDF Downloads 2823116 A Case Study of An Artist Diagnosed with Schizophrenia-Using the Graphic Rorschach (Digital version) “GRD”
Authors: Maiko Kiyohara, Toshiki Ito
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In this study, we used a psychotherapy process for patient with dissociative disorder and the graphic Rorschach (Digital version) (GRD). A dissociative disorder is a type of dissociation characterized by multiple alternating personalities (also called alternate identity or another identity). "dissociation" is a state in which consciousness, memory, thinking, emotion, perception, behavior, body image, and so on are divided and experienced. Dissociation symptoms, such as lack of memory, are seen, and the repetition of blanks in daily events causes serious problems in life. Although the pathological mechanism of dissociation has not yet been fully elucidated, it is said that it is caused by childhood abuse or shocking trauma. In case of Japan, no reliable data has been reported on the number of patients and prevalence of dissociative disorders, no drug is compatible with dissociation symptoms, and no clear treatment has been established. GRD is a method that the author revised in 2017 to a Graphic Rorschach, which is a special technique for subjects to draw language responses when enforce Rorschach. GRD reduces the burden on both the subject and the examiner, reduces the complexity of organizing data, improves the simplicity of organizing data, and improves the accuracy of interpretation by introducing a tablet computer during the drawing reaction. We are conducting research for the purpose. The patient in this case is a woman in her 50s, and has multiple personalities since childhood. At present, there are about 10 personalities whose main personality is just grasped. The patients is raising her junior high school sons as single parent, but personal changes often occur at home, which makes the home environment inferior and economically oppressive, and has severely hindered daily life. In psychotherapy, while a personality different from the main personality has appeared, I have also conducted psychotherapy with her son. In this case, the psychotherapy process and the GRD were performed to understand the personality characteristics, and the possibility of therapeutic significance to personality integration is reported.Keywords: GRD, dissociative disorder, a case study of psychotherapy process, dissociation
Procedia PDF Downloads 1163115 Surface Motion of Anisotropic Half Space Containing an Anisotropic Inclusion under SH Wave
Authors: Yuanda Ma, Zhiyong Zhang, Zailin Yang, Guanxixi Jiang
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Anisotropy is very common in underground media, such as rock, sand, and soil. Hence, the dynamic response of anisotropy medium under elastic waves is significantly different from the isotropic one. Moreover, underground heterogeneities and structures, such as pipelines, cylinders, or tunnels, are usually made by composite materials, leading to the anisotropy of these heterogeneities and structures. Both the anisotropy of the underground medium and the heterogeneities have an effect on the surface motion of the ground. Aiming at providing theoretical references for earthquake engineering and seismology, the surface motion of anisotropic half-space with a cylindrical anisotropic inclusion embedded under the SH wave is investigated in this work. Considering the anisotropy of the underground medium, the governing equation with three elastic parameters of SH wave propagation is introduced. Then, based on the complex function method and multipolar coordinates system, the governing equation in the complex plane is obtained. With the help of a pair of transformation, the governing equation is transformed into a standard form. By means of the same methods, the governing equation of SH wave propagation in the cylindrical inclusion with another three elastic parameters is normalized as well. Subsequently, the scattering wave in the half-space and the standing wave in the inclusion is deduced. Different incident wave angle and anisotropy are considered to obtain the reflected wave. Then the unknown coefficients in scattering wave and standing wave are solved by utilizing the continuous condition at the boundary of the inclusion. Through truncating finite terms of the scattering wave and standing wave, the equation of boundary conditions can be calculated by programs. After verifying the convergence and the precision of the calculation, the validity of the calculation is verified by degrading the model of the problem as well. Some parameters which influence the surface displacement of the half-space is considered: dimensionless wave number, dimensionless depth of the inclusion, anisotropic parameters, wave number ratio, shear modulus ratio. Finally, surface displacement amplitude of the half space with different parameters is calculated and discussed.Keywords: anisotropy, complex function method, sh wave, surface displacement amplitude
Procedia PDF Downloads 1183114 AER Model: An Integrated Artificial Society Modeling Method for Cloud Manufacturing Service Economic System
Authors: Deyu Zhou, Xiao Xue, Lizhen Cui
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With the increasing collaboration among various services and the growing complexity of user demands, there are more and more factors affecting the stable development of the cloud manufacturing service economic system (CMSE). This poses new challenges to the evolution analysis of the CMSE. Many researchers have modeled and analyzed the evolution process of CMSE from the perspectives of individual learning and internal factors influencing the system, but without considering other important characteristics of the system's individuals (such as heterogeneity, bounded rationality, etc.) and the impact of external environmental factors. Therefore, this paper proposes an integrated artificial social model for the cloud manufacturing service economic system, which considers both the characteristics of the system's individuals and the internal and external influencing factors of the system. The model consists of three parts: the Agent model, environment model, and rules model (Agent-Environment-Rules, AER): (1) the Agent model considers important features of the individuals, such as heterogeneity and bounded rationality, based on the adaptive behavior mechanisms of perception, action, and decision-making; (2) the environment model describes the activity space of the individuals (real or virtual environment); (3) the rules model, as the driving force of system evolution, describes the mechanism of the entire system's operation and evolution. Finally, this paper verifies the effectiveness of the AER model through computational and experimental results.Keywords: cloud manufacturing service economic system (CMSE), AER model, artificial social modeling, integrated framework, computing experiment, agent-based modeling, social networks
Procedia PDF Downloads 783113 The Contribution of Experience Scapes to Building Resilience in Communities: A Comparative Case Study Approach in Germany and the Netherlands
Authors: Jorn Fricke, Frans Melissen
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Citizens in urban areas are prone to increased levels of stress due to urbanization, inadequate and overburdened infrastructure and services, and environmental degradation. Moreover, communities are fragile and subject to shocks and stresses through various social and political processes. A loss of (a sense of) community is often seen as related to increasing political and civic disintegration. Feelings of community can manifest themselves in various ways but underlying all these manifestations is the need for trust between people. One of the main drivers of trust between individuals is (shared) experiences. It is these shared experiences that may play an important role in building resilience, i.e., the ability of a community and its members to adapt to and deal with stresses, as well as ensure the ongoing development of a community. So far, experience design, as a discipline and academic field, has mainly focused on designing products or services. However, people-to-people experiences are the ones that play a pivotal role in building inclusiveness, safety, and resilience in communities. These experiences represent challenging objects of design as they develop in an interactive space of spontaneity, serendipity, and uniqueness that is based on intuition, freedom of expression, and interaction. Therefore, there is a need for research to identify which elements are required in designing the social and physical environment (or ‘experience scape’) to increase the chance for people-to-people experiences to be successful and what elements are required for these experiences to help in building resilience in urban communities that can resist shocks and stresses. By means of a comparative case study approach in urban areas in Germany and the Netherlands, using a range of qualitative research methods such as in-depth interviews, focus groups, participant observation, storytelling techniques, and life stories, this research identifies relevant actors and their roles in creating building blocks of optimal experience scrapes for building resilience in communities.Keywords: community development, experiences, experience scapes, resilience
Procedia PDF Downloads 1813112 Modeling Sustainable Truck Rental Operations Using Closed-Loop Supply Chain Network
Authors: Khaled S. Abdallah, Abdel-Aziz M. Mohamed
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Moving industries consume numerous resources and dispose masses of used packaging materials. Proper sorting, recycling and disposing the packaging materials is necessary to avoid a sever pollution disaster. This research paper presents a conceptual model to propose sustainable truck rental operations instead of the regular one. An optimization model was developed to select the locations of truck rental centers, collection sites, maintenance and repair sites, and identify the rental fees to be charged for all routes that maximize the total closed supply chain profits. Fixed costs of vehicle purchasing, costs of constructing collection centers and repair centers, as well as the fixed costs paid to use disposal and recycling centers are considered. Operating costs include the truck maintenance, repair costs as well as the cost of recycling and disposing the packing materials, and the costs of relocating the truck are presented in the model. A mixed integer model is developed followed by a simulation model to examine the factors affecting the operation of the model.Keywords: modeling, truck rental, supply chains management.
Procedia PDF Downloads 2263111 Parameter Optimization and Thermal Simulation in Laser Joining of Coach Peel Panels of Dissimilar Materials
Authors: Masoud Mohammadpour, Blair Carlson, Radovan Kovacevic
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The quality of laser welded-brazed (LWB) joints were strongly dependent on the main process parameters, therefore the effect of laser power (3.2–4 kW), welding speed (60–80 mm/s) and wire feed rate (70–90 mm/s) on mechanical strength and surface roughness were investigated in this study. The comprehensive optimization process by means of response surface methodology (RSM) and desirability function was used for multi-criteria optimization. The experiments were planned based on Box– Behnken design implementing linear and quadratic polynomial equations for predicting the desired output properties. Finally, validation experiments were conducted on an optimized process condition which exhibited good agreement between the predicted and experimental results. AlSi3Mn1 was selected as the filler material for joining aluminum alloy 6022 and hot-dip galvanized steel in coach peel configuration. The high scanning speed could control the thickness of IMC as thin as 5 µm. The thermal simulations of joining process were conducted by the Finite Element Method (FEM), and results were validated through experimental data. The Fe/Al interfacial thermal history evidenced that the duration of critical temperature range (700–900 °C) in this high scanning speed process was less than 1 s. This short interaction time leads to the formation of reaction-control IMC layer instead of diffusion-control mechanisms.Keywords: laser welding-brazing, finite element, response surface methodology (RSM), multi-response optimization, cross-beam laser
Procedia PDF Downloads 3513110 Array Type Miniaturized Ultrasonic Sensors for Detecting Sinkhole in the City
Authors: Won Young Choi, Kwan Kyu Park
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Recently, the road depression happening in the urban area is different from the cause of the sink hole and the generation mechanism occurring in the limestone area. The main cause of sinkholes occurring in the city center is the loss of soil due to the damage of old underground buried materials and groundwater discharge due to large underground excavation works. The method of detecting the sinkhole in the urban area is mostly using the Ground Penetration Radar (GPR). However, it is challenging to implement compact system and detecting watery state since it is based on electromagnetic waves. Although many ultrasonic underground detection studies have been conducted, near-ground detection (several tens of cm to several meters) has been developed for bulk systems using geophones as a receiver. The goal of this work is to fabricate a miniaturized sinkhole detecting system based on low-cost ultrasonic transducers of 40 kHz resonant frequency with high transmission pressure and receiving sensitivity. Motived by biomedical ultrasonic imaging methods, we detect air layers below the ground such as asphalt through the pulse-echo method. To improve image quality using multi-channel, linear array system is implemented, and image is acquired by classical synthetic aperture imaging method. We present the successful feasibility test of multi-channel sinkhole detector based on ultrasonic transducer. In this work, we presented and analyzed image results which are imaged by single channel pulse-echo imaging, synthetic aperture imaging.Keywords: road depression, sinkhole, synthetic aperture imaging, ultrasonic transducer
Procedia PDF Downloads 1413109 An Experience on Urban Regeneration: A Case Study of Isfahan, Iran
Authors: Sedigheh Kalantari, Yaping Huang
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The historic area of cities has experienced different phases of transformation. The beginning of the twentieth century, modernism, and modern development changed the integrated pattern of change and the historic urban quarter were regarded as subject comprehensive redevelopment. In this respect, historic area of Iranian cities have not been safe from these changes and affected by widespread evolutions; in particular after Islamic Revolution eras (1978) cities have traveled through an evolution in conservation and development policies and practices. Moreover, moving toward a specific approach and specific attention paid to the regeneration of the historical urban centers in Iran has started since the 1990s. This reveals the great importance attached to the historical centers of cities. This paper is an approach to examine an experience on urban regeneration in Iran through a case study. The study relies on multiple source of evidence. The use of multiple sources of evidence can help substantially improve the validity and reliability of the research. The empirical core of this research, therefore, rests in the process of urban revitalization of the old square in Isfahan. Isfahan is one of the oldest city of Persia. The historic area of city encompasses a large number of valuable buildings and monuments. One of the cultural and historical region of Isfahan is Atiq Square (Old Square). It has been the backbone node of the city that in course of time has being ignored more and more and transformed negatively. The complex had suffered from insufficiencies especially with respect to social and spatial aspects. Therefore, reorganization of that complex as the main and most important urban center of Isfahan became an inevitable issue; So this paper except from reminding the value of such historic-cultural heritage and review of its transformation, focused on an experience of urban revitalization project in this heritage site. The outcome of this research shows that situated in different socio-economic political and historical contexts and in face of different urban regeneration issues, Iran have displayed significant differences in the way of urban regeneration.Keywords: historic area, Iran, urban regeneration, revitalization
Procedia PDF Downloads 2563108 Development and Validation of Selective Methods for Estimation of Valaciclovir in Pharmaceutical Dosage Form
Authors: Eman M. Morgan, Hayam M. Lotfy, Yasmin M. Fayez, Mohamed Abdelkawy, Engy Shokry
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Two simple, selective, economic, safe, accurate, precise and environmentally friendly methods were developed and validated for the quantitative determination of valaciclovir (VAL) in the presence of its related substances R1 (acyclovir), R2 (guanine) in bulk powder and in the commercial pharmaceutical product containing the drug. Method A is a colorimetric method where VAL selectively reacts with ferric hydroxamate and the developed color was measured at 490 nm over a concentration range of 0.4-2 mg/mL with percentage recovery 100.05 ± 0.58 and correlation coefficient 0.9999. Method B is a reversed phase ultra performance liquid chromatographic technique (UPLC) which is considered superior in technology to the high-performance liquid chromatography with respect to speed, resolution, solvent consumption, time, and cost of analysis. Efficient separation was achieved on Agilent Zorbax CN column using ammonium acetate (0.1%) and acetonitrile as a mobile phase in a linear gradient program. Elution time for the separation was less than 5 min and ultraviolet detection was carried out at 256 nm over a concentration range of 2-50 μg/mL with mean percentage recovery 100.11±0.55 and correlation coefficient 0.9999. The proposed methods were fully validated as per International Conference on Harmonization specifications and effectively applied for the analysis of valaciclovir in pure form and tablets dosage form. Statistical comparison of the results obtained by the proposed and official or reported methods revealed no significant difference in the performance of these methods regarding the accuracy and precision respectively.Keywords: hydroxamic acid, related substances, UPLC, valaciclovir
Procedia PDF Downloads 245