Search results for: joint characteristics

Authors: Patricia Shirley Almeida Prado, Liz Brito, Selma Paixão Argollo, Gracie Moreira, Leticia Matos Sobrinho

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Diffuse idiopathic skeletal hyperostosis (DISH) is a degenerative bone disease also known as Forestier´s disease and ankylosing hyperostosis of the spine is characterized by a tendency toward ossification of half the anterior longitudinal spinal ligament without intervertebral disc disease. DISH is not considered to be osteoarthritis, although the two conditions commonly occur together. Diagnostic criteria include fusion of at least four vertebrae by bony bridges arising from the anterolateral aspect of the vertebral bodies. These vertebral bodies have a 'dripping candle wax' appearance, also can be seen periosteal new bone formation on the anterior surface of the vertebral bodies and there is no ankylosis at zygoapophyseal facet joint. Clinically, patients with DISH tend to be asymptomatic some patients mention moderate pain and stiffness in upper back. This disease is more common in man, uncommon in patients younger than 50 years and rare in patients under 40 years old. In modern populations, DISH is found in association with obesity, (type II) diabetes; abnormal vitamin A metabolism and also associated with higher levels of serum uric acid. There is also some association between the increase of risk of stroke or other cerebrovascular disease. The DISH condition can be confused with Heterotopic Ossification, what is the bone formation in the soft tissues as the result of trauma, wounding, surgery, burnings, prolonged immobility and some central nervous system disorder. All these conditions have been described extensively as myositis ossificans which can be confused with the fibrodysplasia (myositis) ossificans progressive. As in the DISH symptomatology it can be asymptomatic or extensive enough to impair joint function. A third confusion osteoarthritis disease that can bring confusion are the enthesopathies that occur in the entire skeleton being common on the ischial tuberosities, iliac crests, patellae, and calcaneus. Ankylosis of the sacroiliac joint by bony bridges may also be found. CASE 1: this case is skeletal remains presenting skull, some vertebrae and scapulae. This case remains unidentified and due to lack of bone remains. Sex, age and ancestry profile was compromised, however the DISH pathognomonic findings and diagnostic helps to estimate sex and age characteristics. Moreover to presenting DISH these skeletal remains also showed some bone alterations and non-metrics as fusion of the first vertebrae with occipital bone, maxillae and palatine torus and scapular foramen on the right scapulae. CASE 2: this skeleton remains shows an extensive bone heterotopic ossification on the great trochanter area of left femur, right fibula showed a healed fracture in its body however in its inteosseous crest there is an extensive bone growth, also in the Ilium at the region of inferior gluteal line can be observed some pronounced bone growth and the skull presented a pronounced mandibular, maxillary and palatine torus. Despite all these pronounced heterotopic ossification the whole skeleton presents moderate bone overgrowth that is not linked with aging, since the skeleton belongs to a young unidentified individual. The appropriate osteopathological diagnosis support the human identification process through medical reports and also assist with epidemiological data that can strengthen vulnerable anthropological estimates.

Keywords: bone disease, DISH, human identification, human remains

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Authors: Guantao Bai

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Public space is an indispensable and important component of the urban built environment. How to more accurately evaluate the usage characteristics of public space can help improve its spatial quality. Compared to traditional survey methods, computer vision technology based on deep learning has advantages such as dynamic observation and low cost. This study takes the public space of Shaping Park as an example and, based on deep learning computer vision technology, processes and analyzes the image data of the public space to obtain the spatial usage characteristics and spatiotemporal characteristics of the public space. Research has found that the spontaneous activity time in public spaces is relatively random with a relatively short average activity time, while social activities have a relatively stable activity time with a longer average activity time. Computer vision technology based on deep learning can effectively describe the spatial usage characteristics of the research area, making up for the shortcomings of traditional research methods and providing relevant support for creating a good public space.

Keywords: computer vision, deep learning, public spaces, using features

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Authors: D. Gåsvaer, L. Stålberg, A. Fundin, M. Jackson, P. Johansson

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Exploration and exploitation capabilities are both important within Operations as means for improvement when managed separately, and for establishing dynamic improvement capabilities when combined in balance. However, it is unclear what exploration and exploitation capabilities imply in improvement and development work within an operations context. So in order to better understand how to develop exploration and exploitation capabilities within operations, the main characteristics of these constructs needs to be identified and further understood. Thus, the objective of this research is to increase the understanding about exploitation and exploration characteristics, to concretize what they translates to within the context of improvement and development work in an operations unit, and to identify practical challenges. A literature review and a case study are presented. In the literature review, different interpretations of exploration and exploitation are portrayed, key characteristics have been identified, and a deepened understanding of exploration and exploitation characteristics is described. The case in the study is an operations unit, and the aim is to explore to what extent and in what ways exploration and exploitation activities are part of the improvement structures and processes. The contribution includes an identification of key characteristics of exploitation and exploration, as well as an interpretation of the constructs. Further, some practical challenges are identified. For instance, exploration activities tend to be given low priority, both in daily work as in the manufacturing strategy. Also, the overall understanding about the concepts of exploitation and exploration (or any similar aspect of dynamic improvement capabilities) is very low.

Keywords: exploitation, exploration, improvement, lean production, manufacturing

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Authors: Yunusa Audu, Alona Cuevas Linatoc, Aisha Idris

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The maximum carboxylation rate of Rubisco (Vcmax) and the maximum electron transport rate (Jmax), light compensation point (LCP), light saturation point (LSP), maximum photosynthesis (Amax), and apparent quantum yield (Aqy) are gas exchange characteristics that are derived from the carbon dioxide (CO2) and light response curves. This characteristics can be affected by the level of CO2 and light received by the plant. Moreover, the characteristics determines the photosynthetic capacity of the plant. The objective of the study is to evaluate the gas exchange characteristics of selected plant species of UTHM. Photosynthetic carbon dioxide (A\Ci) and light (A/Q) response curves were measured using portable photosynthesis system (LICOR). The results shows that both A/Ci and A/Q curves increases as CO2 and light increases, but reach to a certain point where the curves will become saturated. Spathodea campanulata was having the highest Vcmax (52.14±0.005 µmolCO2 m-2s-1), Jmax (104.461±0.011 µmolCO2 m-2s-1) and Aqy (0.072±0.001 mol CO2 mol-1 photons). The highest LCP was observed in Rhaphis excelsa (69.60±0.067 µmol photons m-2s-1) while the highest LSP was recorded for Costus spicatus (1576.69±0.173 µmol photons m-2s-1). It was concluded that the plants need high light intensity and CO2 for their maximum assimilation rate.

Keywords: Gas, Co2, Exchange, Plants

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Authors: B. Paygozar, S.A. Dizaji

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Adhesive bonding is a highly valued type of fastening mechanical parts in complex structures, where joining some simple components is always needed. This method is of several merits, such as uniform stress distribution, appropriate bonding strength, and fatigue performance, and lightness, thereby outweighing other sorts of bonding methods. This study is to investigate the failure load of adhesive single-strap joints, including adherends of different sizes and materials. This kind of adhesive joint is very practical in different industries, especially when repairing the existing joints or attaching substrates of dissimilar materials. In this research, experimentally validated numerical analyses carried out in a commercial finite element package, ABAQUS, are utilized to extract the failure loads of the joints, based on the cohesive zone model. In addition, the stress analyses of the substrates are performed in order to acquire the effects of lowering the thickness of the substrates on the stress distribution inside them to avoid designs suffering from the necking or failure of the adherends. It was found out that this method of bonding is really feasible in joining dissimilar materials which can be utilized in a variety of applications. Moreover, the stress analyses indicated the minimum thickness for the adherends so as to avoid the failure of them.

Keywords: cohesive zone model, dissimilar materials, failure load, single strap joint

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Authors: Svetlana S. Saveysheva, Victoria E. Vasilenko

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The purpose of the research was to study the emotional and personal characteristics of preschool children in relation to the characteristics of child-parent interaction and deviant parental attitudes. The study involved 172 mothers and 172 children (85 boys and 87 girls) aged 4,5 to 7 years (mean age 6 years) living in St. Petersburg, Russia. Methods used were, demographic questionnaire, projective drawing method 'House-Tree-Man', Test of anxiety (Temml, Dorki, Amen), technique of studying self-esteem 'Ladder', expert evaluation of sociability and aggressiveness, questionnaire for children-parent emotional interaction (E.I. Zaharova) and questionnaire 'Analysis of family relationships' (E.G. Eidemiller, V.V. Yustitsky). Results. The greatest number of links with personal characteristics have received such parental deviant attitudes as overprotection and characteristics of authoritarian style (prohibitions, sanctions). If the mother has such peculiarities of the parental relationship, the child is characterized by lower self-esteem, increased anxiety, distrust of themselves and hostility. Children have more pronounced manifestations of aggression in a conniving and unstable style of parenting. The sensitivity of the mother is positively associated with children’s self-esteem. Unconditional acceptance of the child, the predominance of a positive emotional background, orientation to the state of the child during interaction promote the development of communication skills and reduce of aggressiveness. But the excessive closeness of the mother with the child can make it difficult to develop the communicative skills. Conclusions. The greatest influence on emotional and personal characteristics is provided by such features of the parental relation as overprotection, characteristics of authoritarian style, underdevelopment of the sphere of parental feelings, sensitivity of mother and behavioral manifestations of emotional interaction. Research is supported by RFBR №18-013-00990.

Keywords: characteristics of personality, child-parent interaction, children, deviant parental attitudes

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Authors: Szymon Kowieski, Zygmunt Mikno

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The study involved the optimization of process parameters during resistance spot welding of Al-coated martensitic boron steel 22MnB5, applied in hot stamping, performed using a programme with a multiple current impulse mode and a programme with variable pressure force. The aim of this research work was to determine the possibilities of a growth in welded joint strength and to identify the expansion of a welding lobe. The process parameters were adjusted on the basis of welding process simulation and confronted with experimental data. 22MnB5 steel is known for its tendency to obtain high hardness values in weld nuggets, often leading to interfacial failures (observed in the study-related tests). In addition, during resistance spot welding, many production-related factors can affect process stability, e.g. welding lobe narrowing, and lead to the deterioration of quality. Resistance spot welding performed using the above-named welding programme featuring 3 levels of force made it possible to achieve 82% of welding lobe extension. Joints made using the multiple current impulse program, where the total welding time was below 1.4s, revealed a change in a peeling mode (to full plug) and an increase in weld tensile shear strength of 10%.

Keywords: 22MnB5, hot stamping, interfacial fracture, resistance spot welding, simulation, single lap joint, welding lobe

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Authors: M. H. Ahmadi, A. Mortazavi, H. Zarei

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Several authors have described the main mechanism of formation of cracks in the segment lining during the construction of tunnels with tunnel boring machines. A comprehensive analysis of segmental lining joints may help to guarantee a safe construction during Tunneling and serviceable stages. The most frequent types of segment damage are caused by a condition of uneven segment matching due to contact deficiencies. This paper investigated the interaction mechanism of precast concrete lining joints in tunnels. The Discrete Element Method (DEM) was used to analyze a typical segmental lining model consisting of six segment rings. In the analyses, typical segmental lining design parameters of the Ghomrood water conveyance tunnel, Iran were employed in the study. In the conducted analysis, the worst-case scenario of loading faced during the boring of Ghomrood tunnel was considered. This was associated with the existence of a crushed zone dipping at 75 degree at the location of the key segment. In the analysis, moreover, the effect of changes in horizontal stress ratio on the loads on the segment was assessed. The boundary condition associated with K (ratio of the horizontal to the vertical stress) values of 0.5, 1, 1.5 and 2 were applied to the model and separate analysis was conducted for each case. Important parameters such as stress, moments, and displacements were measured at joint locations and the surrounding rock. Accordingly, the segment joint interactions were assessed and analyzed. Moreover, rock mass properties of the Ghomrood in Ghom were adopted. In this study, the load acting on segments joints are included a crushed zone stratum force that intersect tunnel with 75 slopes in the location of the key segment, gravity force of segments and earth pressures. A numerical investigation was used for different coefficients of stress concentration of 0.5, 1, 1.5, 2 and different geological conditions of saturated crushed zone under the critical scenario. The numerical results also demonstrate that maximum bending moments in longitudinal joints occurred for crushed zone with the weaken strengths (Sandstone). Besides that, increasing the load in segment-stratum interfaces affected radial stress in longitudinal joints and finally the opening of joints occurred.

Keywords: joint, interface, segment, contact

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Authors: Isabel Moscol, Carlos J. Díaz, Ciro Rodríguez

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Hip replacement becomes necessary when a person suffers severe pain or considerable functional limitations and the best option to enhance their quality of life is through the replacement of the damaged joint. One of the main components in femoral prostheses is the stem which distributes the loads from the joint to the proximal femur. To preserve more bone stock and avoid weakening of the diaphysis, a short starting stem was selected, generated from the intramedullary morphology of the patient's femur. It ensures the implantability of the design and leads to geometric delimitation for personalized optimization with machine learning (ML) and metaheuristic algorithms. The present study attempts to design a cementless short stem to make the strain deviation before and after implantation close to zero, promoting its fixation and durability. Regression models developed to estimate the percentage change of maximum principal stresses were used as objective optimization functions by the metaheuristic algorithm. The latter evaluated different geometries of the short stem with the modification of certain parameters in oblique sections from the osteotomy plane. The optimized geometry reached a global stress shielding (SS) of 18.37% with a determination factor (R²) of 0.667. The predicted results favour implantability integration in the short stem optimization to effectively reduce SS in the proximal femur.

Keywords: machine learning techniques, metaheuristic algorithms, short-stem design, stress shielding, hip replacement

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Authors: Gabriel Sitler, Yousef Sardahi, Asad Salem

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This paper presents an optimal and robust sliding mode controller (SMC) to regulate the position of the knee joint angle for patients suffering from knee injuries. The controller imitates the role of active orthoses that produce the joint torques required to overcome gravity and loading forces and regain natural human movements. To this end, a mathematical model of the shank, the lower part of the leg, is derived first and then used for the control system design and computer simulations. The design of the controller is carried out in optimal and multi-objective settings. Four objectives are considered: minimization of the control effort and tracking error; and maximization of the control signal smoothness and closed-loop system’s speed of response. Optimal solutions in terms of the Pareto set and its image, the Pareto front, are obtained. The results show that there are trade-offs among the design objectives and many optimal solutions from which the decision-maker can choose to implement. Also, computer simulations conducted at different points from the Pareto set and assuming knee squat movement demonstrate competing relationships among the design goals. In addition, the proposed control algorithm shows robustness in tracking a standard gait signal when accounting for uncertainty in the shank’s parameters.

Keywords: optimal control, multi-objective optimization, sliding mode control, wearable knee exoskeletons

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Authors: Babatunde Kasim Oladele

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This current study investigated students’ characteristics as factors that influence Mathematics Achievement of junior secondary school students. The study adopted a descriptive survey design. The population of the study was one hundred and twenty-three (123) JSS students of secondary schools in Ibadan North Local Government in Oyo State. A Mathematics achievement test and three questionnaires on student’s self-efficacy belief, attitude, and learning style were the instruments used. Prior to the administration of the constructed mathematics achievement test, 100-item mathematics was subjected to the expert review, and items analysis was carried out. Fifty items were retained. The Cronbach Alpha reliability coefficients of the instruments were 0.71, 0.76, and 0.83, respectively. Collected data were analysed using the frequency count, percentages, mean, standard deviation, and Path Analysis in Amos SPSS Version 20. Students characteristics: gender, age, self-efficacy, attitude and learning style had positive direct effects on students’ achievement in Mathematics as indicated by their respective beta weights (β = 0.36, 0.203, 0.92, 0.079, 0.69 p < 0.05). Consequently, the study concluded that student’s characteristics (Age, gender, and learning style) explained a significant part of the variability in students’ achievement in Mathematics.

Keywords: mathematics achievement, students’ characteristics, junior secondary school, Ibadan

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Authors: Chien-Kuo Chang, Yu-Hsiang Lin, Yi-Yun Tang, Min-Chiu Wu

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With the trend of technological advancement, the harm caused by power outages is substantial, mostly due to problems in the power grid. This highlights the necessity for further improvement in the reliability of the power system. In the power system, gas-insulated switches (GIS) and power cables play a crucial role. Long-term operation under high voltage can cause insulation materials in the equipment to crack, potentially leading to partial discharges. If these partial discharges (PD) can be analyzed, preventative maintenance and replacement of equipment can be carried out, there by improving the reliability of the power grid. This research will diagnose defects by identifying three different defects in GIS and three different defects in straight cable joints, for a total of six types of defects. The partial discharge data measured will be converted through phase analysis diagrams and pulse sequence analysis. Discharge features will be extracted using convolutional image processing, and three different deep learning models, CNN, ResNet18, and MobileNet, will be used for training and evaluation. Class Activation Mapping will be utilized to interpret the black-box problem of deep learning models, with each model achieving an accuracy rate of over 95%. Lastly, the overall model performance will be enhanced through an ensemble learning voting method.

Keywords: partial discharge, gas-insulated switches, straight cable joint, defect identification, deep learning, ensemble learning

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Authors: Olurankinse Felix

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Local governments in Ondo State Nigeria are the third tier of government saddled with the responsibility of providing governance and economic services at the grassroots. To be able to do this, the Constitution of the Federal Republic of Nigeria provided that a proportion of Federation Account be allocated to them in addition to their internally generated revenue. From the allocation and other incidental sources of revenue, the local governments are expected to provide basic infrastructures and other social amenities to better the lots of the rural dwellers. Nevertheless, local governments’ performances in terms of provision of social amenities are without questioning and quite not encouraging. Assessing the performance of local governments in this period of dearth and scarcity of resources is highly indispensable more so that the activities of local governments’ staff are bedeviled and characterized with fraud, corruption and mismanagement. Considering the direct impact of the consequences of their action on the living standard of the rural dwellers therefore calls for the need to evaluate their level of performances using capital budgeting approach. The paper being a time series study adopts the survey design. Data were obtained through secondary source mainly from the Annual financial statements and publication of approved budgets estimates covering the period of study (2008-2012). The use of ratio analysis was employed in analyzing the comparative level of performances of the local governments under study. The result of the study shows that less than 30% of the local governments were able to harness the budgetary allocation to provide amenities to the beneficiaries while majority of the local governments were involved in unethical conduct ranging from theft of fund, corruption, diversion of funds and extra-budgetary activities. Also, there is poor internally generated revenue to complement the statutory allocation and besides, the monthly withholding of larger portions of local government share by the state in the name of joint account were also seen as contributory factors. The study recommends the need for transparency and accountability in public fund management through the oversight function of the state house of assembly. Also local government should be made to be autonomous and independent of the state by jettisoning the idea of joint account.

Keywords: performance, transparency and accountability, capital budgeting, joint account, local government autonomy

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Authors: N. Benabdeslam, N. Bouzidi, F. Atmani, R. Boucif, A. Sakhri

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The objective of this study was to provide answers for a better understanding of the mechanisms involved during grinding. To obtain a phosphate powder, we carry out sieving - grinding circuits for each parameter influencing the process. The analysis of the average particle size of the different tests carried out served in the first place as a basis for the determination of the granulometric curve area, the characteristics and the granular coefficients, then the exploitation of the different results for the calculation of the energies consumed for the fragmentation of different ore types, the energy coefficients as well as the ability to grind. Indeed, a time of 5 to 10 minutes can be chosen as the optimal grinding time in a disc mill for a % in weight of the highest pass. However, grinding time can influence the granular characteristics of ore.

Keywords: characteristic granular, grinding, mineralogical composition, phosphate ore, parameters

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Authors: Daniel P. Clayton, Edward A. Ball

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This paper describes an investigation into the isolation characteristics and bandwidth performance of RF combiners that are used as part of Chireix PA architectures, designed for use in the X-Band range of frequencies. Combiner designs investigated are the typical Chireix and Wilkinson configurations which also include simulation of the Wilkinson using manufacturer’s data for the isolation resistor. Another simulation was the less common approach of using a Branchline coupler to form the combiner, as well as simulation results from adding an additional stage. This paper presents the findings of this investigation and compares the bandwidth performance and isolation characteristics to determine suitability.

Keywords: bandwidth, Chireix, couplers, outphasing, power amplifiers, Wilkinson, X-Band

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Authors: Boualem Chetti

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The dynamic characteristics of a three-lobe journal bearing lubricated with micropolar fluids are determined by the linear stability theory. Lubricating oil containing additives and contaminants is modeled as micropolar fluid. The modified Reynolds equation is obtained using the micropolar lubrication theory and the finite difference technique has been used to solve it. The dynamic characteristics in terms of stiffness, damping coefficients, the critical mass and whirl ratio are determined for various values of size of material characteristic length and the coupling number. The computed results show compared with Newtonian fluids, that micropolar fluid exhibits better stability.

Keywords: three-lobe bearings, micropolar fluid, dynamic characteristics, stability analysis

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Authors: Abdelhalem Shahen

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The world is now experiencing a digital revolution and greatly accelerated technological developments, in addition to the transition from the economy in its traditional form to the digital economy, which has resulted in the emergence of new tools that are appropriate to those developments, and from this, this paper attempts to explore the economic characteristics of the bitcoin currency that circulated recently. Due to the many advantages that distinguish it from money in its traditional forms, which have a range of economic effects. The study found that Bitcoin is among the technological innovations, which contain a set of characteristics that are worth studying, those that make it the focus of attention, such as the digital currency, the peer-to-peer property, Lower and Faster Transaction Costs, transparency, decentralized control, privacy, and Double-Spending, as well as security and Cryptographic, and finally mining.

Keywords: Digital Economics, Digital Currencies, Bitcoin, Features of Bitcoin

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Authors: Serges Mendomo Meye, Li Guowei, Shen Zhenzhong, Gan Lei, Xu Liqun

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Due to the characteristics of high-heap and large-volume, the complex layers of waste and the high-water level of leachate, environmental pollution, and slope instability are easily produced. It is therefore of great significance to research the heterogeneous seepage field and stability of landfills. This paper focuses on the heterogeneous characteristics of the landfill piles and analyzes the seepage field and slope stability of the landfill using statistical and numerical analysis methods. The calculated results are compared with the field measurement and literature research data to verify the reliability of the model, which may provide the basis for the design, safe, and eco-friendly operation of the landfill. The main innovations are as follows: (1) The saturated-unsaturated seepage equation of heterogeneous soil is derived theoretically. The heterogeneous landfill is regarded as composed of infinite layers of homogeneous waste, and a method for establishing the heterogeneous seepage model is proposed. Then the formation law of the stagnant water level of heterogeneous landfills is studied. It is found that the maximum stagnant water level of landfills is higher when considering the heterogeneous seepage characteristics, which harms the stability of landfills. (2) Considering the heterogeneity weight and strength characteristics of waste, a method of establishing a heterogeneous stability model is proposed, and it is extended to the three-dimensional stability study. It is found that the distribution of heterogeneous characteristics has a great influence on the stability of landfill slope. During the operation and management of the landfill, the reservoir bank should also be considered while considering the capacity of the landfill.

Keywords: heterogeneous characteristics, leachate levels, saturated-unsaturated seepage, seepage field, slope stability

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Authors: Salwa Abdelbaki

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This research investigated how leaders develop, asking whether they have been leaders due to their innate abilities or they gain leadership characteristics through interactions based on requirements of a situation. If the first is true, then a leader should be successful in any situation. Otherwise, a leader may succeed only in a specific situation. A series of experiments were carried out on three groups including of males and females. First; a group of 148 students with different specializations had to select a leader. Another group of 51 students had to recall their previous experiences and their knowledge of each other to identify who were leaders in different situations. Then a series of analytic tools were applied to the identified leaders and to the whole groups to find out how leaders were developed. A group of 40 young children was also experimented with to find young leaders among them and to analyze their characteristics.

Keywords: leadership, innate characteristics, situation, leadership theories

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Authors: Norshaffika I. Zaiedy Nor, Andrew P. Smith

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Background: Training is essential to develop individuals’ expertise to meet current and future job demands and to improve work performance. At the same time, individuals’ well-being is crucial to ensure that they can fully and positively carry out their daily duties. In addition to the studies that have examined what constitutes well-being and the factors behind it, many researchers have investigated the predictors of training effectiveness and transfer of training. However, there has been very little integration between them. This study was an attempt to bridge the gap between training effectiveness predictors and well-being. Purpose: This research paper aimed to investigate the association between well-being among employees and psychosocial characteristics, together with training variables. Training variables consist of motivation to learn; learning; implementation intention; and cognitive dissonance. Methodology: In total, 210 workers who had undergone various training programs completed an online survey measuring various psychosocial characteristics, four training variables, and level of well-being. Findings: The results showed that certain types of positive psychosocial characteristics (e.g., positive personality, positive work behaviors, positive work and resources) predict motivation to learn, learning and implementation intention. Meanwhile, negative psychosocial characteristics (e.g. negative work demands and resources, negative coping) predict cognitive dissonance. Also, all the training variables had a moderate to high correlation with well-being. However, after controlling other variables (age, gender, education and psychosocial characteristics), none of the training variables predicted well-being. Self-determination theory, cognitive dissonance theory, and the DRIVE model were used to explain these findings. Conclusion: As there is limited research on the integration of training variables with well-being, this study gives a new perspective in the field of both training and well-being. Further investigations are needed to examine the relationships between them.

Keywords: cognitive dissonance, implementation intention, learning, motivation to learn, psychosocial characteristics, well-being

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Authors: Jimoh Olumide Yusuf

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Various factors have continued to bedevil the effective teaching and learning of English Language in Nigeria and prominent among these factors are learners’ characteristics. Unfortunately, these particular factors seem to have recorded paucity of research efforts by scholars and the problem of lack of proficiency in the target language continues to linger. This study therefore investigates the relationship between specific learners’ characteristics and effective teaching of English as a Second Language (ESL) in senior secondary schools in Nigeria. To this end, Self-Determination, and Integrative Motivation Theories were applied to investigate motivation, language learning, learners’ characteristics and its relationship to language proficiency. A survey of 500 students and 100 English Language teachers across 20 schools was conducted. Descriptive statistics was used to analyze the data and findings revealed that; specific learners’ characteristics such as learners’ age, learning style and motivation significantly determine the performance of students in English Language. Specifically, students with appropriate school age, visual learning style and intrinsic motivation, demonstrated English Language proficiency; as they performed better than students with extrinsic motivation, audio and kinaesthetic learning styles. Moreover, teachers related factors such as teaching experience; teaching strategies and teachers’ extrinsic motivation also emerged as essential correlates of effective language teaching. The findings conclude that learning characteristics are significant factors that should be considered by the teachers and education planners for adequate, sequential and effective implementation of the ESL curriculum in Nigeria.

Keywords: senior secondary school, English as a second language, intrinsic motivation, Kinaesthetic learning style

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Authors: K. S. Agrawal

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The performance of jet ejector was studied in detail by different authors. Several authors have studied mass transfer characteristics like interfacial area, mass transfer coefficients etc. In this paper, we have made an attempt to develop PDE model by considering bubble properties and apply Lattice-Boltzmann technique for PDE model. We may present the results for the interfacial area which we have obtained from our numerical simulation. Later the results are compared with previous work.

Keywords: jet ejector, mass transfer characteristics, numerical simulation, Lattice-Boltzmann technique

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Authors: Jhe-Hao Huang, Kun-Da Wu, Wei-Cheng Shih, Jui-Pin Hung

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This study presented the investigation on the dynamic characteristics of a spindle tool system by experimental and finite element modeling approaches. As well known facts, the machining stability is greatly determined by the dynamic characteristics of the spindle tool system. Therefore, understanding the factors affecting dynamic behavior of a spindle tooling system is a prerequisite in dominating the final machining performance of machine tool system. To this purpose, a physical spindle unit was employed to assess the dynamic characteristics by vibration tests. Then, a three-dimensional finite element model of a high-speed spindle system integrated with tool holder was created to simulate the dynamic behaviors. For modeling the angular contact bearings, a series of spring elements were introduced between the inner and outer rings. The spring constant can be represented by the contact stiffness of the rolling bearing based on Hertz theory. The interface characteristic between spindle nose and tool holder taper can be quantified from the comparison of the measurements and predictions. According to the results obtained from experiments and finite element predictions, the vibration behavior of the spindle is dominated by the bending deformation of the spindle shaft in different modes, which is further determined by the stiffness of the bearings in spindle housing. Also, the spindle unit with tool holder shows a different dynamic behavior from that of spindle without tool holder. This indicates the interface property between tool holder and spindle nose plays an dominance on the dynamic characteristics the spindle tool system. Overall, the dynamic behaviors the spindle with and without tool holder can be successfully investigated through the finite element model proposed in this study. The prediction accuracy is determined by the modeling of the rolling interface of ball bearings in spindles and the interface characteristics between tool holder and spindle nose. Besides, identifications of the interface characteristics of a ball bearing and spindle tool holder are important for the refinement of the spindle tooling system to achieve the optimum machining performance.

Keywords: contact stiffness, dynamic characteristics, spindle, tool holder interface

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Authors: Abdelaziz Rabhi, Mohamed Amrani, Abderrazek Ziane, Nabil Belkadi, Abdelraouf Hocini

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In this paper, a bedimensional simulation program of the electric characteristics of reverse biased lateral polysilicon PIN diode is presented. In this case we have numerically solved the system of partial differential equations formed by Poisson's equation and both continuity equations that take into account the effect of impact ionization. Therefore we will obtain the current-voltage characteristics (I-V) of the reverse-biased structure which may include the effect of breakdown.The geometrical model assumes that the polysilicon layer is composed by a succession of defined mean grain size crystallites, separated by lateral grain boundaries which are parallel to the metallurgic junction.

Keywords: breakdown, polycrystalline silicon, PIN, grain, impact ionization

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Authors: Omar Juhmani

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This paper examines the relation between internal corporate governance and the level of corporate compliance with mandatory IFRS disclosure requirements. The internal corporate governance is measured by board and audit committee characteristics. Using data from Bahrain Stock Exchange, the results show that board independence is positively and significantly associated with level of compliance with IFRS disclosure requirements. This suggests that internal corporate governance mechanisms are effective in the financial reporting practices by increasing the level of compliance with IFRS disclosures. Also, the results of the regression analyses indicate that two of the control variables; company size and audit firm size are significantly positively associated with the level of corporate compliance with mandatory IFRS disclosure requirements in Bahrain.

Keywords: Bahrain, board and audit committee characteristics, compliance, disclosure, IFRS

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Authors: Ugur Senturk, Ibrahım Erdemır, Faruk Guven, Cuma Ece

Abstract:

The objective of this study is to compare flexion and extension movements in knee-joint group by measuring isokinetic knee power of amateur basketball and football players. For this purpose, total 21 players were included, which consist of football players (n=12) and basketball players (n=9), within the age range of 17–20. After receiving the age, length, body weight, vertical jump, and BMI measurements of all subjects, the measurement of lower extremity knee-joint movement (Flexion-Extension) was made with isokinetic dynamometer (isomed 2000) at 60 o/sec. and 240 o/sec. angular velocity. After arrangement and grouping of collected information forms and knee flexion and extension parameters, all data were analyzed with SPSS for Windows. Descriptive analyses of the parameters were made. Non-parametric t test and Mann-Whitney U test were used to compare the parameters of football players and basketball players and to find the inter-group differences. The comparisons and relations in the range p<0.05 and p<0.01 between the groups were surveyed. As a conclusion, no statistical differences were found between isokinetic knee flexion and extension parameters of football and basketball players. However, it was found that the football players were older than the basketball players. In addition to this, the average values of the basketball players in the highest torque and the highest torque average curve were found higher than football players in comparisons of left knee extension. However, it was found that fat levels of the basketball players were found to be higher than the football players.

Keywords: isokinetic contraction, isokinetic dynamometer, peak torque, flexion, extension, football, basketball

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Authors: R. C. Law, Shirley Kang, T. Y. Hin, M. Z. Abdullah

Abstract:

LED technology has been evolving aggressively in recent years from incandescent bulb during older days to as small as chip scale package. It will continue to stay bright in future. As such, there is tremendous pressure to stay competitive in the market by optimizing products to next level of performance and reliability with the shortest time to market. This changes the conventional way of product design and development to virtual prototyping by means of Computer Aided Engineering (CAE). It comprises of the deployment of Finite Element Method (FEM) and Computational Fluid Dynamic (CFD). FEM accelerates the investigation for early detection of failures such as crack, improve the thermal performance of system and enhance solder joint reliability. CFD helps to simulate the flow pattern of molding material as a function of different temperature, molding parameters settings to evaluate failures like voids and displacement. This paper will briefly discuss the procedures and applications of FEM in thermal stress, solder joint reliability and CFD of compression molding in LED CSP. Integration of virtual prototyping in product development had greatly reduced the time to market. Many successful achievements with minimized number of evaluation iterations required in the scope of material, process setting, and package architecture variant have been materialized with this approach.

Keywords: LED, chip scale packaging (CSP), computational fluid dynamic (CFD), virtual prototyping

Procedia PDF Downloads 287

Authors: Ayman Hegab

Abstract:

Increasing evidence supports the use of platelet-rich plasma (PRP) combined with hyaluronic acid (HA) for the treatment of knee osteoarthritis, which effectively promotes cartilage repair. This study aimed to determine whether injection of PRP+HA following arthrocentesis reduces pain and improves maximum incisal opening. This was a single-blind, prospective, randomized control study. The patients were selected based on the Hegab classification: Group I: patients treated with arthrocentesis followed by a single PRP injection; Group II (Control): patients treated with arthrocentesis followed by a single HA injection; and Group III: patients treated with arthrocentesis followed by a single PRP+HA combination injection. The primary predictor variable was the medication used for injection. The primary outcome variables were the maximum voluntary mouth opening and pain index scores. The secondary outcome variable was joint sounds. All outcome variables were assessed and compared among the three groups at baseline and at 1-, 3-, 6-, and 12-month intervals. Other variables, including patients’ age and sex, were evaluated in relation to the patient outcomes. Injecting PRP+HA showed statistically significant improvement in the primary and secondary treatment outcomes over PRP or HA injection throughout the study period (P<0.005). Injection of PRP+HA following arthrocentesis had significant long-term clinical efficacy regarding pain relief that was considered the main concern of both the patient and clinician.

Keywords: TMJ, HA, PRP, osteoarthritis

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Authors: Ferit Çakıcı, M. Kemal Leblebicioğlu

Abstract:

In this study, characteristics and flight test analysis of a fixed-wing unmanned aerial vehicle (UAV) with hover capability is analyzed. The base platform is chosen as a conventional airplane with throttle, ailerons, elevator and rudder control surfaces, that inherently allows level flight. Then this aircraft is mechanically modified by the integration of vertical propellers as in multi rotors in order to provide hover capability. The aircraft is modeled using basic aerodynamical principles and linear models are constructed utilizing small perturbation theory for trim conditions. Flight characteristics are analyzed by benefiting from linear control theory’s state space approach. Distinctive features of the aircraft are discussed based on analysis results with comparison to conventional aircraft platform types. A hybrid control system is proposed in order to reveal unique flight characteristics. The main approach includes design of different controllers for different modes of operation and a hand-over logic that makes flight in an enlarged flight envelope viable. Simulation tests are performed on mathematical models that verify asserted algorithms. Flight tests conducted in real world revealed the applicability of the proposed methods in exploiting fixed-wing and rotary wing characteristics of the aircraft, which provide agility, survivability and functionality.

Keywords: flight test, flight characteristics, hybrid aircraft, unmanned aerial vehicle

Procedia PDF Downloads 329

Authors: Akash Verma, Sujit Kumar Samanta

Abstract:

This study examines a discrete-time Geo/G/1 queueing-inventory system attached with (s, Q) inventory policy. Assume that the customers follow the Bernoulli process on arrival. Each customer demands a single item with arbitrarily distributed service time. The inventory is replenished by an outside supplier, and the lead time for the replenishment is determined by a geometric distribution. There is a single server and infinite waiting space in this facility. Demands must wait in the specified waiting area during a stock-out period. The customers are served on a first-come-first-served basis. With the help of the embedded Markov chain technique, we determine the joint probability distributions of the number of customers in the system and the number of items in stock at the post-departure epoch using the Matrix Analytic approach. We relate the system length distribution at post-departure and outside observer's epochs to determine the joint probability distribution at the outside observer's epoch. We use probability distributions at random epochs to determine the waiting time distribution. We obtain the performance measures to construct the cost function. The optimum values of the order quantity and reordering point are found numerically for the variety of model parameters.

Keywords: discrete-time queueing inventory model, matrix analytic method, waiting-time analysis, cost optimization

Procedia PDF Downloads 42