Search results for: moving obstacles

Authors: S. Sabatino, V. Calderaro, V. Galdi, G. Graber, L. Ippolito

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Climate change is a rapidly growing global threat caused mainly by increased emissions of carbon dioxide (CO₂) into the atmosphere. These emissions come from multiple sources, including industry, power generation, and the transport sector. The need to tackle climate change and reduce CO₂ emissions is indisputable. A crucial solution to achieving decarbonization in the transport sector is the adoption of electric vehicles (EVs). These vehicles use lithium (Li-Ion) batteries as an energy source, making them extremely efficient and with low direct emissions. However, Li-Ion batteries are not without problems, including the risk of overheating and performance degradation. To ensure its safety and longevity, it is essential to use a battery management system (BMS). The BMS constantly monitors battery status, adjusts temperature and cell balance, ensuring optimal performance and preventing dangerous situations. From the monitoring carried out, it is also able to optimally manage the battery to increase its life. Among the parameters monitored by the BMS, the main ones are State of Charge (SoC), State of Health (SoH), and State of Power (SoP). The evaluation of these parameters can be carried out in two ways: offline, using benchtop batteries tested in the laboratory, or online, using batteries installed in moving vehicles. Online estimation is the preferred approach, as it relies on capturing real-time data from batteries while operating in real-life situations, such as in everyday EV use. Actual battery usage conditions are highly variable. Moving vehicles are exposed to a wide range of factors, including temperature variations, different driving styles, and complex charge/discharge cycles. This variability is difficult to replicate in a controlled laboratory environment and can greatly affect performance and battery life. Online estimation captures this variety of conditions, providing a more accurate assessment of battery behavior in real-world situations. In this article, a hybrid approach based on a neural network and a statistical method for real-time estimation of SoC, SoH, and SoP parameters of interest is proposed. These parameters are estimated from the analysis of a one-day driving profile of an electric vehicle, assumed to be divided into the following four phases: (i) Partial discharge (SoC 100% - SoC 50%), (ii) Partial discharge (SoC 50% - SoC 80%), (iii) Deep Discharge (SoC 80% - SoC 30%) (iv) Full charge (SoC 30% - SoC 100%). The neural network predicts the values of ohmic resistance and incremental capacity, while the statistical method is used to estimate the parameters of interest. This reduces the complexity of the model and improves its prediction accuracy. The effectiveness of the proposed model is evaluated by analyzing its performance in terms of square mean error (RMSE) and percentage error (MAPE) and comparing it with the reference method found in the literature.

Keywords: electric vehicle, Li-Ion battery, BMS, state-of-charge, state-of-health, state-of-power, artificial neural networks

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Authors: G. Balogh, I. A. Szabó, P.Z. Kovács

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Mechanical stress has a strong effect on the magnitude of the Barkhausen-noise in structural steels. Because the measurements are performed at the surface of the material, for a sample sheet, the full effect can be described by a biaxial stress field. The measured Barkhausen-noise is dependent on the orientation of the exciting magnetic field relative to the axis of the stress tensor. The sample inhomogenities including the residual stress also modifies the angular dependence of the measured Barkhausen-noise. We have developed a laboratory device with a cross like specimen for bi-axial bending. The measuring head allowed performing excitations in two orthogonal directions. We could excite the two directions independently or simultaneously with different amplitudes. The simultaneous excitation of the two coils could be performed in phase or with a 90 degree phase shift. In principle this allows to measure the Barkhausen-noise at an arbitrary direction without moving the head, or to measure the Barkhausen-noise induced by a rotating magnetic field if a linear superposition of the two fields can be assumed.

Keywords: Barkhausen-noise, bi-axial stress, stress measuring, stress dependency

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Authors: Abbas Moradi, Mohsen Safajoy, Reza Yazdanparast

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Analysis of blade-disc dovetail joints is one of the biggest challenges facing designers of aero-engines. To avoid comparatively expensive experimental full-scale tests, numerical methods can be used to simulate loaded disc-blades assembly. Mortar method provides a powerful and flexible tool for solving frictional contact problems. In this study, 2D frictional contact in dovetail has been analysed based on the mortar algorithm. In order to model the friction, the classical law of coulomb and moving friction cone algorithm is applied. The solution is then obtained by solving the resulting set of non-linear equations using an efficient numerical algorithm based on Newton–Raphson Method. The numerical results show that this approach has better convergence rate and accuracy than other proposed numerical methods.

Keywords: computational contact mechanics, dovetail joints, nonlinear FEM, mortar approach

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Authors: Kaige Shi, Chao Jiang, Xin Li

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The swirl gripper is an electrically activated noncontact handling device that uses swirling airflow to generate a lifting force. This force can be used to pick up a workpiece placed underneath the swirl gripper without any contact. It is applicable, for example, in the semiconductor wafer production line, where contact must be avoided during the handling and moving of a workpiece to minimize damage. When a workpiece levitates underneath a swirl gripper, the gap height between them is crucial for safe handling. Therefore, in this paper, we propose a method to estimate the levitation gap height by detecting pressure at two points. The method is based on theoretical model of the swirl gripper, and has been experimentally verified. Furthermore, the force between the gripper and the workpiece can also be estimated using the detected pressure. As a result, the nonlinear relationship between the force and gap height can be linearized by adjusting the rotating speed of the fan in the swirl gripper according to the estimated force and gap height. The linearized relationship is expected to enhance handling stability of the workpiece.

Keywords: swirl gripper, noncontact handling, levitation, gap height estimation

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Authors: Khen Cohen, Daniel Yankelevich, David Mendlovic, Dan Raviv

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We present a 3D stereo system for high-resolution sensing in both the spatial and the temporal domains by combining a frame-based camera and an event-based camera. We establish a method to merge both devices into one unite system and introduce a calibration process, followed by a correspondence technique and interpolation algorithm for 3D reconstruction. We further provide quantitative analysis about our system in terms of depth resolution and additional parameter analysis. We show experimentally how our system performs temporal super-resolution up to effectively 1ms and can detect fast-moving objects and human micro-movements that can be used for micro-expression analysis. We also demonstrate how our method can extract colored events for an event-based camera without any degradation in the spatial resolution, compared to a colored filter array.

Keywords: DVS-CIS stereo vision, micro-movements, temporal super-resolution, 3D reconstruction

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Authors: Nur Ashida Salim, Muhammad Murtadha Othman, Ismail Musirin, Mohd Salleh Serwan

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Over the past few decades, the power system industry in many developing and developed countries has gone through a restructuring process of the industry where they are moving towards a deregulated power industry. This situation will lead to competition among the generation and distribution companies to achieve a certain objective which is to provide quality and efficient production of electric energy, which will reduce the price of electricity. Therefore it is important to obtain an accurate value of the Available Transfer Capability (ATC) and Transmission Reliability Margin (TRM) in order to ensure the effective power transfer between areas during the occurrence of uncertainties in the system. In this paper, the TRM and ATC is determined by taking into consideration the uncertainties of the system operating condition and system cascading collapse by applying the bootstrap technique. A case study of the IEEE RTS-79 is employed to verify the robustness of the technique proposed in the determination of TRM and ATC.

Keywords: available transfer capability, bootstrap technique, cascading collapse, transmission reliability margin

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Authors: K. Durairaj, I. N. Umar

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Lately, asynchronous discussion forum is integrated in higher educational institutions as it may increase learning process, learners’ understanding, achievement and knowledge construction. Asynchronous discussion forum is used to complement the traditional, face-to-face learning session in hybrid learning courses. However, studies have proven that students’ engagement in online forum are still unconvincing. Thus, the aim of this study is to investigate the motivating factors and obstacles that affect the learners’ engagement in asynchronous discussion forum. This study is carried out in one of the public higher educational institutions in Malaysia with 18 postgraduate students as samples. The authors have developed a 40-items questionnaire based on literature review. The results indicate several factors that have encouraged or limited students’ engagement in asynchronous discussion forum: (a) the practices or behaviors of peers, or instructors, (b) the needs for the discussions, (c) the learners’ personalities, (d) constraints in continuing the discussion forum, (e) lack of ideas, (f) the level of thoughts, (g) the level of knowledge construction, (h) technical problems, (i) time constraints and (j) misunderstanding. This study suggests some recommendations to increase the students’ engagement in online forums. Finally, based upon the findings, some implications are proposed for further research.

Keywords: asynchronous discussion forum, engagement, factors, motivating, limiting

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Authors: Rachel Gugu Mkhasibe

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Incorporation of technology as a pedagogy has many benefits. For instance, improvement of pedagogy, increased information access, increased cooperation, and collaboration. However, as good as it may be, this integration of technology as a pedagogy has not been widely adopted in most historically Black higher education institutions especially those in developing countries. For example, the socioeconomic background of students in historically black universities, the weak financial support available from these universities, as well as a large population of students struggle to access the recommended modern physical resources such as iPads, laptops, mobile phones, to name a few. This contributes to an increase in the increase of educational inequalities. The qualitative research approach was utilized in this work to gather detailed data about the obstacles created by the integration of technology as a pedagogy. Interviews were conducted to generate data from 20 academics from 10 Leve two students from one of the historically disadvantaged higher education Institutions in South Africa. The findings revealed that although both students and academics had overwhelming support of the integration of technology as a pedagogy in their institution, the environment which they found themselves in compromise the incorporation of technology as a pedagogy. Therefore, this paper recommends that Department of Higher Education and University Management should intervene and budget for technology to be provided in all the institutions of higher education regardless of where the institutions are situated.

Keywords: collaboration, integration, pedagogy, technology

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Authors: Yihua Wang, Yunru Lai

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Statistical process control has been successfully applied in a variety of industries. In some applications, the quality of a process or product is better characterized and summarized by a functional relationship between a response variable and one or more explanatory variables. A collection of this type of data is called a profile. Profile monitoring is used to understand and check the stability of this relationship or curve over time. The independent assumption for the error term is commonly used in the existing profile monitoring studies. However, in many applications, the profile data show correlations over time. Therefore, we focus on a general linear regression model with a first-order autocorrelation between profiles in this study. We propose an exponentially weighted moving average charting scheme to monitor this type of profile. The simulation study shows that our proposed methods outperform the existing schemes based on the average run length criterion.

Keywords: autocorrelation, EWMA control chart, general linear regression model, profile monitoring

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Authors: Tahereh Samenian

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There is ample evidence that source and goal are disproportionately expressed in languages, and goal usually plays a more prominent role than source. The results show that the mismatch between the goal and the source is not entirely rooted in non-linguistic behaviors, i.e. that linguistic descriptions also show the focus of the goal on the source in events; Non-verbal memory for events, on the other hand, indicates that the focus of the goal is only on events that are purposefully moving and the actor is alive. In the present study, an attempt is made to examine the principle of priority of the goal over the source by focusing on Persian directional motion verbs. For this purpose, 117 Persian directional motion verbs have been selected from the dictionary and data for them have been collected from the body of Bijan Khan and the components of goal and source have been identified in sentences and the prominence of the components of goal and source has been shown in the form of diagrams. As it was obtained from the data, Persian motion-directional verbs also showed the bias of the goal over source in motion events.

Keywords: motion-directional verbs, priority of goal over source principle, cognitive factors, linguistic factors

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Authors: Fatima Gouiferda

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Uncertainty and competitiveness are changing firm’s environment to become more complicated. The competition is moving to supply chain’s level, and firms need to collaborate and innovate to survive. In the current economy, common efforts between organizations and developing new capacities mutually are the key resources in gaining collaborative advantage and enhancing supply chain performance. The purpose of this paper is to explore different practices of collaboration activities that exist in the pharmaceutical industry of Morocco. Also, to inquire how these practices affect supply chain performance. The exploration is based on interpretativism research paradigm. Data were collected through semi-structured interviews from supply chain practitioners. Qualitative data was analyzed via Iramuteq software to explore different themes of the study.The findings include descriptive analysis as a result of data processing using Iramuteq. It also encompasses the content analysis of the themes extracted from interviews.

Keywords: inter-firm relationships, collaboration, supply chain innovation, morocco

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Authors: Alaa Alshehri

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It has been thought that kinship in modernization is moving in a linear Western model; however, the literature shows that different cultures adjust to modernization by preserving its norms and values. Saudi Arabia is a young country experiencing rapid expansion from oil discovery until economic diversification. By conducting 10 interviews from different provinces of the country from the age of 27-47, these anthropological studies suggest that Saudi people adapted to modernization and globalization through unique interactions with extended families by asking the participants to give detailed descriptions of their interactions with their kinship. With almost all the participants noticing the changes within the last few years, this interaction is rooted in their religious beliefs, which they stressed, even with the free choice of life opportunities. They tried to find a balance between individuality and collectivity and connect the gap between the older and younger generations. This study adds to the anthropological debate on kinship definition and ties in modernization and provides a perspective on the social reality of one of the major Middle Eastern countries, Saudi Arabia.

Keywords: collectivity, economic diversification, kinship, modernization theory, individuality

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Authors: Kaoru Tomita

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This study explores how visual information helps us to learn foreign language pronunciation. Visual assistance and its effect for learning foreign language have been discussed widely. For example, simplified illustrations in textbooks are used for telling learners which part of the articulation organs are used for pronouncing sounds. Vowels are put into a chart that depicts a vowel space. Consonants are put into a table that contains two axes of place and manner of articulation. When comparing a still picture and a moving picture for visualizing learners’ pronunciation, it becomes clear that the former works better than the latter. The visualization of vowels was applied to class activities in which native and non-native speakers’ English was compared and the learners’ feedback was collected: the positions of six vowels did not scatter as much as they were expected to do. Specifically, two vowels were not discriminated and were arranged very close in the vowel space. It was surprising for the author to find that learners liked analyzing their own pronunciation by linking formant ones and twos on a sheet of paper with a pencil. Even a simple method works well if it leads learners to think about their pronunciation analytically.

Keywords: feedback, pronunciation, visualization, vowel

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Authors: Nigel P. Coutts, Stellina Z. Sim

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Research suggests that the pedagogy we utilize when teaching mathematics contributes to a negative attitude towards the discipline. Worried by this, we have explored teaching mathematics for understanding, fluency, and confidence. We investigated strategies to engage students with the beauty of mathematics, moving them beyond mimicry and memorization. The result is an integrated pedagogy and curriculum arrangement which combines concept-based mathematics with Number Talks, Visible Thinking Routines, and Teaching for Understanding. Our qualitative research shows that students self-report greater self-confidence and heightened engagement with mathematical thinking. Teacher reflections on student learning echo this finding. As a result of this, we advocate for teacher training in the implementation of a concept-based curriculum supplemented with Number Talk strategies.

Keywords: mathematical thinking, teaching for understanding, student confidence, concept-based learning, engagement

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Authors: Rudolf L. Kanyane, Nicolaus Malatji, Patritia A. Popoola

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Tribological failure of materials during application can lead to catastrophic events which also carry economic penalties. High entropy alloys (HEAs) have shown outstanding tribological properties in applications such as mechanical parts were moving parts under high friction are required. This work aims to investigate the effect of sintering temperature on microhardness properties and tribological properties of novel equiatomic TiAlMoSiW HEAs fabricated via spark plasma sintering. The effect of Spark plasma sintering temperature on morphological evolution and phase formation was also investigated. The microstructure and the phases formed for the developed HEAs were examined using scanning electron microscopy (SEM) and X-ray diffractometry (XRD) respectively. The microhardness and tribological properties were studied using a diamond base microhardness tester Rtec tribometer. The developed HEAs showed improved mechanical properties as the sintering temperature increases.

Keywords: sintering, high entropy alloy, microhardness, tribology

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Authors: P. C. Chiu, Jehnming Lin

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In this study, a 50-W CO₂ laser was used for the clad of 304L powders on the stainless steel substrate with a temperature sensor and image monitoring system. The laser power and cladding speed and focal position were modified to achieve the requirement of the workpiece flatness and mechanical properties. The numerical calculation is based on ANSYS to analyze the temperature change of the moving heat source at different surface positions when coating the workpiece, and the effect of the process parameters on the bath size was discussed. The temperature of stainless steel powder in the nozzle outlet reacting with the laser was simulated as a process parameter. In the experiment, the difference of the thermal conductivity in three-dimensional space is compared with single-layer cladding and multi-layer cladding. The heat dissipation pattern of the single-layer cladding is the steel plate and the multi-layer coating is the workpiece itself. The relationship between the multi-clad temperature and the profile was analyzed by the temperature signal from an IR pyrometer.

Keywords: laser cladding, temperature, profile, microstructure

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Authors: Taehoon Kwon, Hyeongrae Cho, Dirk Henkensmeier, Youngjong Kang, Chong Min Koo

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Ionic polymer actuators have been of interest in the bio-inspired artificial muscle devices. However, the relatively slow response and low power density were the obstacles for practical applications. In this study, ionic polymer actuators are fabricated with ionic polymer composite membranes based on sulfonated poly(arylene ether sulfone) (SPAES) and copper(II) phthalocyanine tetrasulfonic acid (CuPCSA). CuPCSA is an organic filler with very high ion exchange capacity (IEC, 4.5 mmol H+/g) that can be homogeneously dispersed on the molecular scale into the SPAES membrane. SPAES/CuPCSA actuators show larger ionic conductivity, mechanical properties, bending deformation, exceptional faster response to electrical stimuli, and larger mechanical power density (3028 W m–3) than Nafion actuators. This outstanding actuation performance of SPAES/CuPCSA composite membrane actuators makes them attractive for next generation transducers with high power density, which are currently developed biomimetic devices such as endoscopic surgery.

Keywords: actuation performance, composite membranes, ionic polymer actuators, organic filler

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Authors: Takesure Mahohoma

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Community life is an epitome of the African axiom 'I am because we are, since we are therefore I am.' This culminates in the Ubuntu philosophy which is summarized in the Zulu words, 'umuntu ngumuntu ngabantu' (A person is a person through other people). This relationship gives honour to all people. This is the gist of the paper. This paper seeks to demonstrate the impact of community life in promoting unity from an African perspective. Using the proto-community in Acts 2:42, it is argued that community life is a solution to many social problems that divide African society today. The aim is to encourage all Africans and other people to cultivate a sense of belonging and valuing community life in the light of Acts 2:42. Hence we shall trace this theme from Old Testament, New Testament, and Christian history. The other section touches on the essence of community life and obstacles that hinder it. We shall offer spiritual suggestions and an integrative reflection. The nature of the paper is theology in general but spiritual in particular. As a spiritual paper, it is guided by the foundational approach. Thus, it employs the dialogical and integrative reflection method. The expected result is that freedom from all the miseries experienced is brought by living a community life. This is a life that gives greater assurance of enough food, education, health, peace, employment, and increased responsibility that values human dignity. Thus people are neighbours to each other. There is no stranger among them. The basic presumption is that there can be no development in any society without community life.

Keywords: community, seged, koinonia, neighbor

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Authors: W. H. Wan Zakiyatussariroh, A. A. Nasuhar, W. Y. Wan Fairos, Z. A. Nazatul Shahreen

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Forecasting dengue incidence in a population can provide useful information to facilitate the planning of the public health intervention. Many studies on dengue cases in Malaysia were conducted but are limited in modeling the outbreak and forecasting incidence. This article attempts to propose the most appropriate time series model to explain the behavior of dengue incidence in Malaysia for the purpose of forecasting future dengue outbreaks. Several seasonal auto-regressive integrated moving average (SARIMA) models were developed to model Malaysia’s number of dengue incidence on weekly data collected from January 2001 to December 2011. SARIMA (2,1,1)(1,1,1)52 model was found to be the most suitable model for Malaysia’s dengue incidence with the least value of Akaike information criteria (AIC) and Bayesian information criteria (BIC) for in-sample fitting. The models further evaluate out-sample forecast accuracy using four different accuracy measures. The results indicate that SARIMA (2,1,1)(1,1,1)52 performed well for both in-sample fitting and out-sample evaluation.

Keywords: time series modeling, Box-Jenkins, SARIMA, forecasting

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Authors: (Ted) Edward Holmberg, Mahdi Abdelguerfi, Elias Ioup

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This research details a coverage measure for evaluating the effectiveness of observer node placements in a spatial bipartite network. This coverage measure can be used to optimize the configuration of stationary or mobile spatially oriented observer nodes, or a hybrid of the two, over time in order to fully utilize their capabilities. To demonstrate the practical application of this approach, we construct a SpatioTemporal Bipartite Network (STBN) using real-time crime center (RTCC) camera nodes and NOPD calls for service (CFS) event nodes from New Orleans, La (NOLA). We use the coverage measure to identify optimal placements for moving mobile RTCC camera vans to improve coverage of vulnerable areas based on temporal patterns.

Keywords: coverage measure, mobile node dynamics, Monte Carlo simulation, observer nodes, observable nodes, spatiotemporal bipartite knowledge graph, temporal spatial analysis

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Authors: Maarten J. Van der Burgt

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A universe containing matter and antimatter can only exist when matter and antimatter repel each other. Such a system, where like attracts like and like repels unlike, will always expand. Calculations made for such a symmetric universe demonstrate that the expansion is consistent with Hubble’s law, the observed increase in the expansion velocity with time, the initial high acceleration and the foam structure of the universe. Conversely, these observations can be considered as proof for a symmetrical universe and for antimatter possessing a negative gravitational mass. A second proof can be found by reinterpreting the behavior of relativistic moving charged particles. Attributing their behavior to a charge defect of √(1-v2/c2) instead of to a mass defect of 1/√(1-v2/c2) makes it plausible that gravitation is an electromagnetic force, as already suggested by Feynman. This would automatically imply that antimatter has a negative gravitational mass. These proofs underpin the untenability of the Weak Equivalence Principle which states that in a gravitational field all structure less point-like particles follow the same path.

Keywords: celestial mechanics, cosmology, gravitation astrophysics, origin of structure, miscellaneous (matter and antimatter)

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Authors: Abosede Mosunmola Odeseye

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The sustainability of nations’ economies today have proven to be unrealistic in a constantly changing world without appropriate accordance to entrepreneurship role and its processes. This role has therefore proven to be a product of the available and discoverable opportunities by an individual/organisation in any pattern – innovation, discovery, diffusion, imitation amidst possible challenges. In light of these, this paper examined the relationship between opportunity development and entrepreneurial processes as well as the factors determining individual’s opportunity development and the success of entrepreneurial processes. Systematic review method was adopted for selecting relevant academic materials. The theoretical base of this paper was anchored on Schumpeter’s entrepreneurial innovation model and Drucker and Stevenson’s opportunity-based entrepreneurship theory. Based on the reviewed literature, it was discovered that rough business idea “opportunity” in any form – techniques/product encounter various obstacles to achieve its development, acceptability and sustainability. In essence, the findings revealed that the birth of every opportunity is as a result of the individual/organisation and environmental factors to be able to scale through the whole process successfully. Due to the outcome of this paper, it was recommended that the organisations/government should endeavour to create an enabling environment for a rough business idea to come to life amidst the hurdles of the entrepreneurial process.

Keywords: entrepreneurial process, entrepreneurship, opportunity, opportunity development, organisation, sustainability

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Authors: Imine Zakaria, Meftah Sidi Mohamed El Amine

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One of the most vital aerodynamic organs of a flying machine is the wing, which allows it to fly in the air efficiently. The flow around the wing is very sensitive to changes in the angle of attack. Beyond a value, there is a phenomenon of the boundary layer separation on the upper surface, which causes instability and total degradation of aerodynamic performance called a stall. However, controlling flow around an airfoil has become a researcher concern in the aeronautics field. There are two techniques for controlling flow around a wing to improve its aerodynamic performance: passive and active controls. Blowing and suction are among the active techniques that control the boundary layer separation around an airfoil. Their objective is to give energy to the air particles in the boundary layer separation zones and to create vortex structures that will homogenize the velocity near the wall and allow control. Blowing and suction have long been used as flow control actuators around obstacles. In 1904 Prandtl applied a permanent blowing to a cylinder to delay the boundary layer separation. In the present study, several numerical investigations have been developed to predict a turbulent flow around an aerodynamic profile. CFD code was used for several angles of attack in order to validate the present work with that of the literature in the case of a clean profile. The variation of the lift coefficient CL with the momentum coefficient

Keywords: CFD, control flow, lift, slot

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Authors: Khelfaoui Rachid, Chekifi Tawfiq, Dennai Brahim, Maazouzi A. Hak

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A numerical and experimental studies of passive micro drops production have been presented. This paper focuses on the modeling of micro-oscillators systems which are composed by passive amplifier without moving part. The micro-system modeling is based on geometrical oscillators form. An asymmetric micro-oscillator design that is based on a bistable fluidic amplifier is proposed. The characteristic size of the channels is generally about 35 microns of depth. The numerical results indicate that the production and manipulation of microdrops are possible with passive device within a typical oscillators chamber of 2.25 mm diameter and 0.20 mm length when the Reynolds number is Re = 490. The novel micro drops method that is presented in this study provides a simple solution about the production of microdrops problems in micro system. We undertake an experimental step. The first part is based on the realisation of sample oscillator; the second part is consisted of visualization, production and manipulation of microdrops.

Keywords: modelling, miscible, micro drops, production, oscillator sample, capillary

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Authors: Kun Xue, Lvlan Miu, Jiarui Li

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Jetting structures are widely found in particle rings or shells dispersed by the central explosion. In contrast, some explosive dispersal of particles only results in a dispersed cloud without distinctive structures. Employing the coupling method of the compressible computational fluid mechanics and discrete element method (CCFD-DEM), we reveal the underlying physics governing the formation of the jetting structure, which is related to the competition between the shock compaction and gas infiltration, two major processes during the shock interaction with the granular media. If the shock compaction exceeds the gas infiltration, the discernable jetting structures are expected, precipitated by the agglomerates of fast-moving particles induced by the heterogenous network of force chains. Otherwise, particles are uniformly accelerated by the interstitial flows, and no distinguishable jetting structures are formed. We proceed to devise the phase map of the jetting formation in the space defined by two dimensionless parameters which characterize the timescales of the shock compaction and the gas infiltration, respectively.

Keywords: compressible multiphase flows, DEM, granular jetting, pattern formation

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Authors: Nahla Khatib

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This study investigated several learning difficulties that affected the classroom learning experience of preservice students who are studying general science and methods of teaching science students at Faculty of Educational Studies at the Arab Open University (AOU) in Amman, Jordan. The focus questions for this study were to find answers for the following: 1. What are the main areas of learning difficulty among preservice students towards science education? 2. What are the main aspects of reducing obstacles towards success in science education? To achieve this goal, the researcher prepared a questionnaire which included 30 items to point out the learning difficulties among preservice students towards science education. The questionnaire was distributed among students enrolled in the general science courses 1&2 and methods of teaching science courses at the beginning of the spring semester of year (2013-2014). After collecting the filled questionnaire a descriptive statistical analysis was carried out (means and standard deviation) for the items of the questionnaire. After analyzing the data statistically our findings showed that student control–factors as well as course controlled factor, factors related to the nature of science, and factors related to the role of instructor affected student success toward science education. The study was concluded with a number of recommendations.

Keywords: nature of science, preservice teachers, science education, learning difficulties

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Authors: Takashi Shimizu, Tomoaki Hashimoto

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Recently, crystal growth technologies have made progress by the requirement for the high quality of crystal materials. To control the crystal growth dynamics actively by external forces is useuful for reducing composition non-uniformity. In this study, a control method based on model predictive control using thermal inputs is proposed for crystal growth dynamics of semiconductor materials. The control system of crystal growth dynamics considered here is governed by the continuity, momentum, energy, and mass transport equations. To establish the control method for such thermal fluid systems, we adopt model predictive control known as a kind of optimal feedback control in which the control performance over a finite future is optimized with a performance index that has a moving initial time and terminal time. The objective of this study is to establish a model predictive control method for crystal growth dynamics of semiconductor materials.

Keywords: model predictive control, optimal control, process control, crystal growth

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Authors: Ghaleb Y. Abbasi, Satanay Alhiary

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This paper focused on software testing phase of activities, types, techniques, teams and methods under agile project management (APM) in the Jordanian software industry. The effect of using agile principles and practices on testing process in software development life cycle (SDLC) was analyzed in order to create full view of the agile testing aspects such as phases, levels, types, methods, team and customers. Qualitative and quantitative research methods were utilized to cover earlier literature and collect data via web survey and short interviews in Jordanian software companies. Results indicated that agile testing had positive influence on quality of product, team performance, and customer satisfaction with a rate above 80%. APM is a powerful practice of moving software project forward in current markets with a rate above 51% by early involvement of testing activities in development.

Keywords: agile project management, software development life cycle, agile methods, agile testing, software testing

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Authors: Todd R. Walton

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Social media would seem to be an ideal mechanism for crisis communication, yet it has been met with varied results. Natural disasters, such as hurricanes, provide a slow moving view of how social media can be leveraged to guide stakeholders and the public through a crisis. Crisis communication managers have struggled to reach target audiences with credible messaging. This Qualitative Evidence Synthesis (QES) analyzed the findings of eight studies published in the last year to determine how organizations effectively utilize social media for crisis communication. Additionally, the evidence was analyzed to note strategies for establishing credibility in a medium fraught with misinformation. Studies indicated wide agreement on the use of multiple social media channels in addition to frequent accurate messaging in order to establish credibility. Studies indicated mixed agreement on the use of text based emergency notification systems. The findings in this QES will help crisis communication professionals plan for social media use for crisis communication.

Keywords: crisis communication, crisis management, emergency response, social media

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Authors: Geoff Skinner, Ilung Pranata

Abstract:

The advancement of ICT innovations provides us with a comfortable and convenient modern lifestyle. However, this modern easy lifestyle is proving to have some serious health consequences. Such technological advancements that have dramatically increased ones time in front of screens have been a contributing factor to increasing rates of obesity. In particular the youth obesity issue has gained more and more attention from researchers and health institutions around the world. Although technology innovations may lead to a sedate modern life, they also have a potential to solve the obesity issue in children. This paper provides a review of the issues in child obesity and the potential of active video games to mitigate these issues. Additionally, the paper also discusses the key requirements to develop an active video game that hopes to help combat child obesity through motivating youth to exergame. A framework is introduced to meet the requirements, from which a prototype was implemented. Discussion of the simulation and testing that were performed to verify the attainment of objectives is also detailed.

Keywords: e-video games, exergaming, health informatics, human computer interaction

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