Search results for: in order to escape from the radiation

Authors: Suyong Kim

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Recently because of the rise in the price of rare earth magnet, interest of non-rare earth or less-rare earth motor is growing. Especially to achieve the high power density, Spoke-Type BLDC (Brushless Permanent Magnet) Motor with ferrite permanent magnet are spotlighted. But Spoke-Type Ferrite BLDC Motor has much of magnetic flux leakage in the direction of rotor shaft. In order to solve this problem, there are two conventional ways. But conventional ways bring the increases of product cost or the decreases of the power density. Therefore, this paper proposes new Spoke-Type BLDC Rotor shape that has the advantages of both conventional methods. The new shape is consists of a one-piece core. The inside and the outside of the rotor are open alternately. So it can take reduced production cost and high power density.

Keywords: motor, BLDC, spoke, ferrite

Procedia PDF Downloads 553

Authors: Anna Kolanowska, Anna Kuziel, Sławomir Boncel

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Carbon nanotubes (CNTs) represent a combination of lightness and nanoscopic size with high tensile strength, excellent thermal and electrical conductivity. By now, CNTs have been used as a support in heterogeneous catalysis (CuCl anchored to pre-functionalized CNTs) in the Ullmann-type coupling with aryl halides toward formation of C-N and C-O bonds. The results indicated that the stability of the catalyst was much improved and the elaborated catalytic system was efficient and recyclable. However, CNTs have not been considered as the substrate itself in the Ullmann-type reactions. But if successful, this functionalization would open new areas of CNT chemistry leading to enhanced in-solvent/matrix nanotube individualization. The copper-catalyzed Ullmann-type reaction is an attractive method for the formation of carbon-heteroatom and carbon-carbon bonds in organic synthesis. This condensation reaction is usually conducted at temperature as high as 200 oC, often in the presence of stoichiometric amounts of copper reagent and with activated aryl halides. However, a small amount of organic additive (e.g. diamines, amino acids, diols, 1,10-phenanthroline) can be applied in order to increase the solubility and stability of copper catalyst, and at the same time to allow performing the reaction under mild conditions. The copper (pre-)catalyst is prepared by in situ mixing of copper salt and the appropriate chelator. Our research is focused on the application of Ullmann-type reaction for the covalent functionalization of CNTs. Firstly, CNTs were chlorinated by using iodine trichloride (ICl3) in carbon tetrachloride (CCl4). This method involves formation of several chemical species (ICl, Cl2 and I2Cl6), but the most reactive is the dimer. The fact (that the dimer is the main individual in CCl4) is the reason for high reactivity and possibly high functionalization levels of CNTs. This method, indeed, yielded a notable amount of chlorine onto the MWCNT surface. The next step was the reaction of CNT-Cl with three substrates: aniline, iodobenzene and phenol for the formation C-N, C-C and C-O bonds, respectively, in the presence of 1,10-phenanthroline and cesium carbonate (Cs2CO3) as a base. As the CNT substrates, two multi-wall CNT (MWCNT) types were used: commercially available Nanocyl NC7000™ (9.6 nm diameter, 1.5 µm length, 90% purity) and thicker MWCNTs (in-house) synthesized in our laboratory using catalytic chemical vapour deposition (c-CVD). In-house CNTs had diameter ranging between 60-70 nm and length up to 300 µm. Since classical Ullmann reaction was found as suffering from poor yields, we have investigated the effect of various solvents (toluene, acetonitrile, dimethyl sulfoxide and N,N-dimethylformamide) on the coupling of substrates. Owing to the fact that the aryl halides show the reactivity order of I>Br>Cl>F, we have also investigated the effect of iodine presence on CNT surface on reaction yield. In this case, in first step we have used iodine monochloride instead of iodine trichloride. Finally, we have used the optimized reaction conditions with p-bromophenol and 1,2,4-trihydroxybenzene for the control of CNT dispersion.

Keywords: carbon nanotubes, coupling reaction, functionalization, Ullmann reaction

Procedia PDF Downloads 151

Authors: Kavish Kejriwal, Richa Grover

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Consumer awareness and pending legislation have pushed environmental issues into the spotlight, making it imperative for organizations to have a plan of action for “going green.” This is the reason why Green Supply Chain Management has become the integral part of many organization with a goal to reduce cost, increase efficiency and be environmental friendly. Implementation of GSCM involves many factors which act as barriers, making it a tedious task. These barriers have different relationship among themselves creating different impact on implementation Green Supply Chain Management. This work focuses on determining those barriers which have essentially to be removed in the initial stages of GSCM adoption. In this work, the author has taken the case of a petroleum industry in order to come up with a solution. A DEMATEL approach is used to reach the solution.

Keywords: barriers, environment, green supply chain management, impact, interpretive structural modeling

Procedia PDF Downloads 258

Authors: Haojie Wang, Xun Li, Rui Yin

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In order to solve the memorization overfitting in the model-agnostic meta-learning MAML algorithm, a method of generating mutually exclusive tasks based on data augmentation is proposed. This method generates a mutex task by corresponding one feature of the data to multiple labels so that the generated mutex task is inconsistent with the data distribution in the initial dataset. Because generating mutex tasks for all data will produce a large number of invalid data and, in the worst case, lead to an exponential growth of computation, this paper also proposes a key data extraction method that only extract part of the data to generate the mutex task. The experiments show that the method of generating mutually exclusive tasks can effectively solve the memorization overfitting in the meta-learning MAML algorithm.

Keywords: mutex task generation, data augmentation, meta-learning, text classification.

Procedia PDF Downloads 120

Authors: Elena Barbaro, Elena Gregoris, Rossano Piazza, Boris Mifka, Tatjana Ivošević, Ivo Orlić, Ana Alebić-Juretić, Andrea Gambaro, Daniele Contini

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The aim of the POSEIDON project is to quantify the relative contribution of maritime traffic and harbor activities to atmospheric pollutants concentration in four port-cities of the Adriatic Sea. This study focuses on the harbors of Venice and Rijeka. In order to investigate the main pollution sources, emission inventories were used as input for receptor models: PMF (positive matrix factorization) and PCA (principal components analysis); moreover source identification was also conducted using PAHs diagnostic ratios. The ship traffic impact was quantified: i) on gaseous and particulate PAHs, collected using a new method which consisted in a double simultaneous sampling, in different wind sectors; ii) applying PMF to data of metals, PAHs and ions in PM10; iii) using the vanadium concentration according to the Agrawal methodology.

Keywords: ship traffic, PMF, harbor, POSEIDON

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Authors: Ali Mithad Emre

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In military aviation, the use of flight simulators has proliferated recently in order to train fifth generation fighter pilots. With these simulators, pilots can carry out real-time flights resulting in seeing their faults and can perform emergency drills prior to real flights. Since we cannot risk losing the aircraft and the pilot himself/herself in the flight training process, flight simulators are of great importance to adapt the fighter pilots competently to real flights aboard the fifth generation aircraft. The real flights are impossible to simulate thoroughly on the ground. To some extent, the fixed-based simulators may assist the pilot to steer aircraft technically and visually but flight simulators can’t trick the pilot’s vestibular, sensory, and perceptual systems without motion platforms. This paper discusses the benefits of motion simulators for fifth generation fighter pilots’ training in preference to the fixed-based counterparts by analyzing their pros and cons.

Keywords: military, pilot, sickness, simulator

Procedia PDF Downloads 456

Authors: Tian Lan, Yixiang Wang, Wenxin Tai, Yilan Lyu, Zufeng Wu

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The monaural speech enhancement task in the time-frequencydomain has a myriad of approaches, with the stacked con-volutional neural network (CNN) demonstrating superiorability in feature extraction and selection. However, usingstacked single convolutions method limits feature represen-tation capability and generalization ability. In order to solvethe aforementioned problem, we propose an attention-basedadaptive convolutional network that integrates the multi-scale convolutional operations into a operation-specific blockvia input dependent attention to adapt to complex auditoryscenes. In addition, we introduce a two-stage progressivelearning method to enlarge the receptive field without a dra-matic increase in computation burden. We conduct a series ofexperiments based on the TIMIT corpus, and the experimen-tal results prove that our proposed model is better than thestate-of-art models on all metrics.

Keywords: speech enhancement, adaptive convolu-tion, progressive learning, time-frequency domain

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Authors: D. Romero Espitia

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Research on peacebuilding has taken a critical turn into examining the neoliberal and hegemonic conception of peace operations. Alternative peacebuilding models have been analyzed, but the scholarly discussion fails to bring them together or form connections between them. The objective of this paper is to rethink peacebuilding by extracting the positive aspects of the various peacebuilding models, connecting them with the local context, and therefore promote emancipation in contemporary peacebuilding efforts. Moreover, local ownership has been widely labelled as one, if not the core principle necessary for a successful peacebuilding project. Yet, definitions of what constitutes the 'local' remain debated. Through a qualitative review of literature, this paper unpacks the contemporary conception of peacebuilding in nexus with 'local ownership' as manifested through civil society. Using Colombia as a case study, this paper argues that a new peacebuilding framework, one that reconsiders the terms of engagement between international and national actors, is needed in order to foster effective peacebuilding efforts in contested transitional states.

Keywords: civil society, Colombia, emancipation, peacebuilding

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Authors: Ricardo Merlo

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The use of simulation as a digital didactic tool allowed students to reproduce the laws of Physics in order to improve their academic performance. The didactic resource of simulation also favored the motivation of most of the young people, depending on the subject of Physics to be developed in the classroom and in that sense, it was significant to know the favorable or unfavorable attitude that the students presented about the use of simulation resources to maximize the anchorage of the contents planned for the different classes developed in the classroom. The different real-time simulation applications that were offered free of charge through the Internet were not presented as a specific resource that could be used in a didactic model, and in that framework, the teachers of Physics at the university level did not apply these resources in a systematic way with the knowledge of the favorable or unfavorable attitude of the students towards these didactic resources. For this reason, this work proposed the design and application of attitude questionnaires to enhance the use of those simulation resources that allowed for improving the quality of the class and the academic performance of the students.

Keywords: physics teaching, attitude, motivation, didactic resources

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Authors: Md Tanvir Rahman, Mahbube Subhani, Mahmud Ashraf, Paul Kremer

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Cross-laminated timber (CLT) is made from layers of timber boards orthogonally oriented in the thickness direction, and due to this, CLT can withstand bi-axial bending in contrast with most other engineered wood products such as laminated veneer lumber (LVL) and glued laminated timber (GLT). Wood is cylindrically anisotropic in nature and is characterized by significantly lower elastic modulus and shear modulus in the planes perpendicular to the fibre direction, and is therefore classified as orthotropic material and is thus characterized by 9 elastic constants which are three elastic modulus in longitudinal direction, tangential direction and radial direction, three shear modulus in longitudinal tangential plane, longitudinal radial plane and radial tangential plane and three Poisson’s ratio. For simplification, timber materials are generally assumed to be transversely isotropic, reducing the number of elastic properties characterizing it to 5, where the longitudinal plane and radial planes are assumed to be planes of symmetry. The validity of this assumption was investigated through numerical modelling of CLT with both orthotropic mechanical properties and transversely isotropic material properties for three softwood species, which are Norway spruce, Douglas fir, Radiata pine, and three hardwood species, namely Victorian ash, Beech wood, and Aspen subjected to uniformly distributed loading under simply supported boundary condition. It was concluded that assuming the timber to be transversely isotropic results in a negligible error in the order of 1 percent. It was also observed that along with longitudinal elastic modulus, ratio of longitudinal shear modulus (GL) and rolling shear modulus (GR) has a significant effect on a deflection for CLT panels of lower span to depth ratio. For softwoods such as Norway spruce and Radiata pine, the ratio of longitudinal shear modulus, GL to rolling shear modulus GR is reported to be in the order of 12 to 15 times in literature. This results in shear flexibility in transverse layers leading to increased deflection under out-of-plane loading. The rolling shear modulus of hardwoods has been found to be significantly higher than those of softwoods, where the ratio between longitudinal shear modulus to rolling shear modulus as low as 4. This has resulted in a significant rise in research into the manufacturing of CLT from entirely from hardwood, as well as from a combination of softwood and hardwoods. The commonly used beam theory to analyze the performance of CLT panels under out-of-plane loads are the Shear analogy method, Gamma method, and k-method. The shear analogy method has been found to be the most effective method where shear deformation is significant. The effect of the ratio of longitudinal shear modulus and rolling shear modulus of cross-layer on the deflection of CLT under uniformly distributed load with respect to its length to depth ratio was investigated using shear analogy method. It was observed that shear deflection is reduced significantly as the ratio of the shear modulus of the longitudinal layer and rolling shear modulus of cross-layer decreases. This indicates that there is significant room for improvement of the bending performance of CLT through developing hybrid CLT from a mix of softwood and hardwood.

Keywords: rolling shear modulus, shear deflection, ratio of shear modulus and rolling shear modulus, timber

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Authors: Gheorghe Braniste

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The management of the training process in sports is closely related to the awareness of the close connection between performance and the morphological, functional and psychological characteristics of the athlete's body. Achieving high results in Olympic sports is influenced, on the one hand, by the genetically determined characteristics of the body and, on the other hand, by the morphological, functional and motor abilities of the athlete. Taking into account the importance of properly understanding the evolutionary specificity of athletes to assess their competitive potential, this study provides a comparative analysis of the parameters that characterize the growth and development of the level of adaptation of sweeping rowers, considering the growth interval between 12 and 20 years. The study established that, in the multi-annual training process, the bodies of the targeted athletes register significant adaptive changes while analyzing parameters of the morphological, functional, psychomotor and sports-technical spheres. As a result of the influence of physical efforts, both specific and non-specific, there is an increase in the adaptability of the body, its transfer to a much higher level of functionality within the parameters, useful and economical adaptive reactions influenced by environmental factors, be they internal or external. The research was carried out for 7 years, on a group of 28 athletes, following their evolution and recording the specific parameters of each age stage. In order to determine the level of physical, morpho-functional, psychomotor development and technical training of rowers, the screening data were applied at the State University of Physical Education and Sports in the Republic of Moldova. During the research, measurements were made on the waist, in the standing and sitting position, arm span, weight, circumference and chest perimeter, vital capacity of the lungs, with the subsequent determination of the vital index (tolerance level to oxygen deficiency in venous blood in Stange and Genchi breath-taking tests that characterize the level of oxygen saturation, absolute and relative strength of the hand and back, calculation of body mass and morphological maturity indices (Kettle index), body surface area (body gait), psychomotor tests (Romberg test), test-tepping 10 s., reaction to a moving object, visual and auditory-motor reaction, recording of technical parameters of rowing on a competitive distance of 200 m. At the end of the study it was found that highly performance is sports is to be associated on the one hand with the genetically determined characteristics of the body and, on the other hand, with favorable adaptive reactions and energy saving, as well as morphofunctional changes influenced by internal and external environmental factors. The importance of the results obtained at the end of the study was positively reflected in obtaining the maximum level of training of athletes in order to demonstrate performance in large-scale competitions and mostly in the Olympic Games.

Keywords: olympics, parameters, performance, peak

Procedia PDF Downloads 108

Authors: Hui-Yu Peng, Hsiu-I Hsueh, Li-Ming Chen

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Most studies focused on bullying behaviors among students, however few research concerns about teachers’ bullying behaviors against students. In order to have more understandings and reduce teacher bullying, it is important to examine what factors may affect teachers’ bullying behaviors. This study aimed to explore the connections between different psychological variables and teacher bullying. Four variables, neuroticism, extraversion, teacher-student relationship, and belief in a just world for others (BJW-others), were selected in this study. Four hundred and five elementary and secondary school teachers in Taiwan endorsed the self-reported surveys. Multiple regression method was used to analyze data. Results revealed that teachers’ BJW-others and extraversion did not have significant correlations with teacher bullying scores. However, closed teacher-student relationship and neuroticism can negatively and positively predict teachers’ bullying behaviors against students, respectively. Implications for preventing teacher bullying were discussed at the end of this study.

Keywords: belief in a just world for others, big five personality traits, teacher bullying, teacher-student relationship

Procedia PDF Downloads 191

Authors: Agarana Michael C., Akinlabi Esther T., Pule Kholopane

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In order to sustain the advantages of an advanced manufacturing technique, such as laser sintering, minimization of total processing cost of the parts being produced is very important. An efficient time management would usually very important in optimal cost attainment which would ultimately result in an efficient advanced manufacturing process planning and control. During Laser Scanning Process Scanning (SLS) procedures it is possible to adjust various manufacturing parameters which are used to influence the improvement of various mechanical and other properties of the products. In this study, Modelling and mathematical analysis, including sensitivity analysis, of the laser sintering process time were carried out. The results of the analyses were represented with graphs, from where conclusions were drawn. It was specifically observed that achievement of optimal total scanning time is key for economic efficiency which is required for sustainability of the process.

Keywords: modeling and analysis, optimal planning and control, laser sintering process, scanning time

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Authors: D. Olszewska, J. Niewiedzial

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In some types of Li-ion batteries carbon in the form of graphite is used. Unfortunately, carbon materials, in particular graphite, have very good electrochemical properties, but increase their volume during charge/discharge cycles, which may even lead to an explosion of the cell. The cell element may be replaced by a composite material consisting of lithium-titanium oxide Li4Ti5O12 (LTO) modified with copper and nickel ions and carbon derived from sucrose. This way you can improve the conductivity of the material. LTO is appropriate only for applications which do not require high energy density because of its high operating voltage (ca. 1.5 V vs. Li/Li+). Specific capacity of Li4Ti5O12 is high enough for utilization in Li-ion batteries (theoretical capacity 175 mAh·g-1) but it is lower than capacity of graphite anodes. Materials based on Li4Ti5O12 do not change their volume during charging/discharging cycles, however, LTO has low conductivity. Another positive aspect of the use of sucrose in the carbon composite material is to eliminate the addition of carbon black from the anode of the battery. Therefore, the proposed materials contribute significantly to environmental protection and safety of selected lithium cells. New anode materials in order to obtain Li3.8Cu0.1Ni0.1Ti5O12 have been prepared by solid state synthesis using three-way: i) stoichiometric composition of Li2CO3, TiO2, CuO, NiO (A- Li3.8Cu0.1Ni0.1Ti5O12); ii) stoichiometric composition of Li2CO3, TiO2, Cu(NO3)2, Ni(NO3)2 (B-Li3.8Cu0.1Ni0.1Ti5O12); and iii) stoichiometric composition of Li2CO3, TiO2, CuO, NiO calcined with 10% of saccharose (Li3.8Cu0.1Ni0.1Ti5O12-C). Structure of materials was studied by X-ray diffraction (XRD). The electrochemical properties were performed using appropriately prepared cell Li|Li+|Li3.8Cu0.1Ni0.1Ti5O12 for cyclic voltammetry and discharge/charge measurements. The cells were periodically charged and discharged in the voltage range from 1.3 to 2.0 V applying constant charge/discharge current in order to determine the specific capacity of each electrode. Measurements at various values of the charge/discharge current (from C/10 to 5C) were carried out. Cyclic voltammetry investigation was carried out by applying to the cells a voltage linearly changing over time at a rate of 0.1 mV·s-1 (in the range from 2.0 to 1.3 V and from 1.3 to 2.0 V). The XRD method analyzes show that composite powders were obtained containing, in addition to the main phase, 4.78% and 4% TiO2 in A-Li3.8Cu0.1Ni0.1O12 and B-Li3.8Cu0.1Ni0.1O12, respectively. However, Li3.8Cu0.1Ni0.1O12-C material is three-phase: 63.84% of the main phase, 17.49 TiO2 and 18.67 Li2TiO3. Voltammograms of electrodes containing materials A-Li3.8Cu0.1Ni0.1O12 and B-Li3.8Cu0.1Ni0.1O12 are correct and repeatable. Peak cathode occurs for both samples at a potential approx. 1.52±0.01 V relative to a lithium electrode, while the anodic peak at potential approx. 1.65±0.05 V relative to a lithium electrode. Voltammogram of Li3.8Cu0.1Ni0.1Ti5O12-C (especially for the first measurement cycle) is not correct. There are large variations in values of specific current, which are not characteristic for materials LTO. From the point of view of safety and environmentally friendly production of Li-ion cells eliminating soot and applying Li3.8Cu0.1Ni0.1Ti5O12-C as an active material of an anode in lithium-ion batteries seems to be a good alternative to currently used materials.

Keywords: anode, Li-ion batteries, Li₄O₅O₁₂, spinel

Procedia PDF Downloads 138

Authors: Saurav Bhattacharjee, Syam Nair

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Lime stabilization is a sustainable and economically viable option to address strength deficiencies of subgrade soils. However, exposure of stabilized layers to environmental elements can lead to a reduction in post stabilization strength gain expected in these layers. The current study investigates the impact of carbonation on strength properties of lime-treated soils. Manufactured soils prepared using varying proportions of bentonite silica mixtures was used in the study. Lime treated mixtures were exposed to different atmospheric conditions created by varying the concentrations of CO₂ in the testing chamber. Impact of CO₂ diffusion was identified based on changes in carbonate content and strength (UCS) properties. Changes in soil morphology were also investigated as part of the study. Rate of carbonation was observed to vary polynomially (2nd order) with exposure time. Strength properties of the mixes were observed to decrease with exposure time.

Keywords: carbonation, soil, stabilization, morphology

Procedia PDF Downloads 52

Authors: Aristeidis Samitas, Stathis Polyzos

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As the UK and the EU prepare to start negotiations for Brexit, it is important for both sides to comprehend the full extent of the consequences of this process. In this paper, we employ an object oriented simulation framework in order to test for the short-term and long-term effects of Brexit on both sides of the Channel. The relative strength of the UK economy and the banking sector vis-à-vis the EU is taken under consideration. Our results confirm predictions in the relevant literature regarding the output cost of Brexit, with particular emphasis on the EU. Furthermore, we show that financial stability is also an important issue on both sides, with the banking system suffering significant losses, particularly over the longer term. Our findings suggest that policymakers should be extremely careful in handling Brexit negotiations, making sure to consider dynamic effects that may be caused by UK bank assets moving to the EU after Brexit. The model results show that, as the UK banking system loses its assets, the end state of the UK economy is deteriorated while the end state of EU economy is improved.

Keywords: Banking Crises, Brexit, Financial Stability, VBanking

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Authors: Dalila Chaid, Yacine Houmel, Mohamed Lamine Belloulou

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Peripheral neuropathy is a rare but worrying complication of peripheral local anaesthesia. It is caused either by needle contact with the nerve root or by the direct toxicity of local anaesthetics, leading to nerve damage, injury or irritation. Although uncommon, it remains a major concern for anaesthetists. The aim of the study was to assess the prevalence of nerve block-associated neuropathy in knee surgery and to identify the contributing factors in order to minimise the occurrence of this complication. The study also assessed the severity and evolution of lesions, as well as the factors leading to neuropathic pain. Methodology: It is a retrospective observational study on cases of neuropathy related to nerve blocks of the lower limb for knee surgery over a period of seven years (2016-2022). The study included a total of 6,000 patients Analyse the anaesthetic and neuropathic pain-related parameters received from these patients to determine the prevalence and severity of neuropathy. Findings: the prevalence of nerve block-related neuropathy in our study is 5.8‰ for the sciatic nerve and 0.9‰ for the femoral nerve. This was higher compared to the reported rates in the literature, which were between 0.0 to 5‰ for the Sciatic nerve and 0.0 to 3.4‰ for the femoral nerve. These findings highlight the importance of identifying and implementing an ideal anesthesia procedure to reduce the risk of neuropathy associated with nerve blocks. Theoretical Importance: The findings of this study contribute to the existing literature on peripheral neuropathy following locoregional anesthesia. By identifying the prevalence and severity of neuropathy related to nerve blocks, as well as the underlying factors, we provide valuable insights for anesthetists to improve patient safety. This study also emphasizes the need for compliance with technical safety rules to minimize the occurrence of neuropathy. Data Collection and Analysis Procedures: For this study, 25 clinics with retrospective data were collected of neuropathy associated with nerve blocks for knee surgery over a span of seven years. Parameters related to anaesthesia and neuropathic pain were analysed to determine prevalence,severity, and progression of neuropathy. Comparison of our results with the existing literature in order to assess their significance. Questions Addressed: This study aims to define the following points: 1. The prevalence of neuropathy associated with nerve blocks for knee surgery. 2. The factors underlying the development of neuropathy after nerve blocks. 3. Reducing the risk of neuropathy by complying with technical safety rules. 4. Assessing the severity and evolution of neuropathic pain in these cases. Conclusion: this study highlights the need for careful consideration and implementation of anesthesia procedures during nerve blocks for knee surgery. The prevalence of neuropathy linked to these blocks was higher compared to the literature, emphasizing the importance of identifying and minimizing contributing factors. Compliance with technical safety rules is crucial to reduce the risk of peripheral neuropathy. This study provides valuable insights to anesthetists and contributes to improving patient safety in the field of locoregional anesthesia.

Keywords: phantom limb, neuropathic pain, lower limb amputee, ultrasound-guided locoreginal anesthesia

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Authors: Chaouch Souad, Abdou Latifa, Larbi Chrifi Alaoui

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This paper deals with sensorless backstepping control of induction motor using MRAS technique associated to sliding mode approach. A high order genetic algorithm structure is used to approximate a control law designed by the Backstepping technique, and to find the best parameters globally optimized. However, the Backstepping control approach is unsuitable for high performance applications because the need of a speed sensor for increased accuracy and the absence of any error decay mechanism. In this paper a nonlinear observer, obtained by combining sliding mode structure and model reference adaptive system (MRAS), is designed for the rotor flux and rotor speed estimations. To validate the proposed method, the results are presented for showing the improved drive characteristics and performances.

Keywords: Backstepping Control, Induction Motor, Genetic Algorithm, Sliding Mode observer

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Authors: Alam Ali, Ashok Kumar Pathak

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Path analysis is a statistical technique used to evaluate the strength of the direct and indirect effects of variables. One or more structural regression equations are used to estimate a series of parameters in order to find the better fit of data. Sometimes, exogenous variables do not show a significant strength of their direct and indirect effect when the assumption of classical regression (ordinary least squares (OLS)) are violated by the nature of the data. The main motive of this article is to investigate the efficacy of the copula-based regression approach over the classical regression approach and calculate the direct and indirect effects of variables when data violates the OLS assumption and variables are linked through an elliptical copula. We perform this study using a well-organized numerical scheme. Finally, a real data application is also presented to demonstrate the performance of the superiority of the copula approach.

Keywords: path analysis, copula-based regression models, direct and indirect effects, k-fold cross validation technique

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Authors: Raziye Atakan, Ebru Celebi, Gulay Ozcan, Neda Soydan, A. Sezai Sarac

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In this study, a novel polymeric flame retardant chemical with phosphorous-nitrogen synergism was synthesized by polyvinyl alcohol (PVA), hydrophilic polyester resin (PR), phosphoric acid and dicyandiamide (DCDA). Polyester/Cotton (Pes/Co) blend fabrics were treated via pad-dry-cure process with this synthesized chemical. PVA (PR)-P-DCDA has shown that it is an effective flame retardant on the fabrics. In order to improve durable flame retardancy for cotton part of the blend, polysilicic acid and citric acid monohydrate auxiliaries were added in FR finishing bath at different concentrations. Flammability and characteristic properties of the sample were tested according to relevant ISO standard and procedures. To do so, ISO 6940 vertical flammability test, TGA, DTA, LOI and FTIR analysis have been performed. The obtained results showed that this new finishing formulation is a good char-forming agent for the PES/CO blends and polysilicic acid could be used for cellulosic blends with PVA (PR)-P-DCDA.

Keywords: flame retardancy, flammability, Pes/Co blends, polysilicic acid

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Authors: Nathalie Gagnon, Andréanne Gagné, Julie Courcy

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Quebec's vocational education teachers experience an atypical induction process into the workplace and thus face unique challenges. In contrast to elementary and high school teachers, who must undergo initial teacher training in order to access the profession, vocational education teachers, in most cases, are hired based on their professional expertise in the trade they are teaching, without prior pedagogical training. In addition to creating significant stress, which does not foster the acquisition of teaching roles and skills, this approach also forces recruits into a particular posture during their practical training: that of juggling their dual identities as teacher and trainee simultaneously. Recruits are supported by Cooperating Teachers (CPs) who, as experienced educators, take a critical and constructive look at their practices, observe them in the classroom, give them constructive feedback, and encourage them in their reflective practice. Thus, the vocational setting CP also assumes a distinctive posture and role due to the characteristics of the trainees they support. Although it is recognized that preparation, training, and supervision of CPs are essential factors in improving the support provided to trainees, there is little research about how CPs develop their support skills, and very little research focuses on the distinct posture they occupy. However, in order for them to be properly equipped for the important role they play in recruits’ practical training, it is vital to know more about their experience. An individual’s competencies cannot be studied without first examining what characterizes their experience, how they experience any given situation on cognitive, emotional, and motivational levels, in addition to how they act and react in situ. Depending on its nature, the experience will or will not promote the development of a specific competency. The research from which this communication originates focuses on describing the overall experience of vocational education CP in an effort to better understand the mechanisms linked to the development of their mentoring competencies. Experience and competence were, therefore, the two main theoretical concepts leading the research. As per methodology choices, case study methods were used since it proves to be adequate to describe in a rich and detailed way contemporary phenomena within contexts of life. The set of data used was collected from semi-structured interviews conducted with 15 vocational education CP in Quebec (Canada), followed by the use of a data-driven semi-inductive analysis approach to let the categories emerge organically. Focusing on the development needs of vocational education CP to improve their mentoring skills, this paper presents the results of our research, namely the importance of adequate training, better support offered by university supervisors, greater recognition of their role, and specific time slots dedicated to trainee support. The knowledge resulting from this research could improve the quality of support for trainee teachers in vocational education settings and to a more successful induction into the workplace. This communication also presents recommendations regarding the development of training systems that meet the specific needs of vocational education CP.

Keywords: development of competencies, cooperating teacher, mentoring trainee teacher, practical training, vocational education

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Authors: Naji Ali Albakay, Abdulrahman Alothaim, Isa Barshushi

Abstract:

The most common quadrature amplitude modulator (QAM) applies two Mach-Zehnder Modulators (MZM) and one phase shifter to generate high order modulation format. The bias of MZM changes over time due to temperature, vibration, and aging factors. The change in the biasing causes distortion to the generated QAM signal which leads to deterioration of bit error rate (BER) performance. Therefore, it is critical to be able to lock MZM’s Q point to the required operating point for good performance. We propose a technique for automatic bias control (ABC) of QAM transmitter using BER measurements and gradient descent optimization algorithm. The proposed technique is attractive because it uses the pertinent metric, BER, which compensates for bias drifting independently from other system variations such as laser source output power. The proposed scheme performance and its operating principles are simulated using OptiSystem simulation software for 4-QAM and 16-QAM transmitters.

Keywords: automatic bias control, optical fiber communication, optical modulation, optical devices

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Authors: Rie Adachi

Abstract:

In Japan, it is required to improve students’ English communicative proficiency and the Education Ministry will start English education for the third grade and upper from year 2020 on. Considering the problems with the educational system, Content and Language Integrated Learning (CLIL) is more appropriate to be employed in elementary schools rather than just introducing English lessons. Effective CLIL takes place in the 4Cs Framework, and different strategies are used in various activities, such as arts and crafts, bodily expression, singing, playing roles, etc. After a CLIL workshop for local teachers focused on the 4Cs, the writer conducted a survey of the 36 participants using a questionnaire and found that they did not know the word CLIL, but seemed to have an interest after attending the workshop. The writer concluded that researchers and practitioners need to spread awareness of the 4Cs framework, to apply CLIL into Japanese educational context, to provide CLIL teacher training program and so on, in order to practice CLIL in Japanese elementary schools and nurture students with a global mindset.

Keywords: CLIL, 4Cs, homeroom teachers, intercultural understanding

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Authors: Nikhil V. Nayak

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In this paper, the influence of air cooling intake on the gas turbine performance is presented. A comparison among different cooling systems, i.e., evaporative and cooling coil, is performed. A computer simulation model for the employed systems is developed in order to evaluate the performance of the studied gas turbine unit, at Marka Power Station, Amman, Bangalore. The performance characteristics are examined for a set of actual operational parameters including ambient temperature, relative humidity, turbine inlet temperature, pressure ratio, etc. The obtained results showed that the evaporative cooling system is capable of boosting the power and enhancing the efficiency of the studied gas turbine unit in a way much cheaper than cooling coil system due to its high power consumption required to run the vapor-compression refrigeration unit. Nevertheless, it provides full control on the temperature inlet conditions regardless of the relative humidity ratio.

Keywords: power augmentation, temperature control, evaporative cooling, cooling coil, gas turbine

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Authors: Mehmet Durnali

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The main purpose of this study is to find out, analyze and discuss basic principles of education and training in the constitutions, including the latest amendment, of France, Indonesia, Japan, South Africa, the United States of America, and Turkey. This research specifically aims at establishing a framework in order to compare educational values such as right of education, responsibilities of states and those of people, and other issues pertaining to education in the Constitution of Turkey to others. Additionally, it emphasizes the meaning of education in constitution, the reasons for references to education in constitutions and why it is important for people, states or nations and state organs. Qualitative analysis technique is performed to accomplish the aim of this study. Maximum variation sampling is used. The main data source of the analysis is official organic laws of those countries. The data is examined by using descriptive and content analysis method.

Keywords: education in the constitution, education law, legal principles of education, right to education

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Authors: Joy Aworookoroh

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Writing is one of the active skills in language learning. Students of English as a foreign language are expected to write efficiently and proficiently in the language; however, there are usually challenges to optimal performance and competence in writing. Errors, on the other hand, in a foreign language learning situation are more positive than negative as they provide the basis for solving the limitations of the students. This paper investigates the situation in the Department of English, Taraba State University Jalingo. Students are administered a descriptive writing test across different levels of study. The target students are multilingual with an L1 of either Kuteb, Hausa or Junkun languages. The essays are accessed to identify the different kinds of errors in them alongside the classification of the order. Errors of correctness, clarity, engagement, and delivery were identified. However, the study identified that the degree of errors reduces alongside the experience and exposure of the students to an EFL classroom.

Keywords: errors, writings, descriptive essay, multilingual

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Authors: Kaivan Karami, Sahalu Hassan, Sanna Taking, Afesome Ofiare, Aniket Dhongde, Abdullah Al-Khalidi, Edward Wasige

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We have made a comparative study on the influence of Al₂O₃ and HfO₂ grown using atomic layer deposition (ALD) technique as dielectric in the AlGaN/GaN metal oxide semiconductor high electron mobility transistor (MOS-HEMT) structure. Five samples consisting of 20 nm and 10 nm each of Al₂O₃ and HfO₂ respectively and a Schottky gate HEMT, were fabricated and measured. The threshold voltage shifts towards negative by 0.1 V and 1.8 V for 10 nm thick HfO2 and 10 nm thick Al₂O₃ gate dielectric layers respectively. The negative shift for the 20 nm HfO2 and 20 nm Al₂O₃ were 1.2 V and 4.9 V respectively. Higher gm/IDS (transconductance to drain current) ratio was also obtained in HfO₂ than Al₂O₃. With both materials as dielectric, a significant reduction in the gate leakage current in the order of 10^4 was obtained compared to the sample without the dielectric material.

Keywords: AlGaN/GaN HEMTs, Al2O3, HfO2, MOSHEMTs.

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Authors: Denver E. Severt, Cynthia Mejia

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With a grey wave sweeping across the world and people living longer than ever, more individuals will reside in retirement communities in unprecedented numbers. Enhancing the resident stay within these communities is imperative to reduce past stigmas associated with senior communities. This exploratory quantitative investigation examined interview contents of employees and residents to see if empathy was observed. The results showed the employees across all ranges had a much better grasp of affective empathy, yet with greater experience and age, it was clear that cognitive empathy had to be used with affective empathy in order to gain better trust across the community of residents. Outcomes from the study suggest that future training programs for employees are operationalized to include both affective and cognitive empathy practices. This study is unique in that two scales of empathy were transformed into qualitative questions, and in-depth employee and resident interviews were conducted. The study answers many calls of research to provide more specific studies in senior living communities.

Keywords: senior living community, transformational service research, qualitative research

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Authors: Brittany E. Coff, Tommy K. K. Ngai, Laura A. S. MacDonald

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Many organizations in the Water, Sanitation and Hygiene (WASH) sector provide education and training in order to increase the effectiveness of their WASH interventions. A key challenge for these organizations is measuring how well their education and training activities contribute to WASH improvements. It is crucial for implementers to understand the returns of their education and training activities so that they can improve and make better progress toward the desired outcomes. This paper presents information on CAWST’s development and piloting of the evaluation methodology. The Centre for Affordable Water and Sanitation Technology (CAWST) has developed a methodology for evaluating education and training activities, so that organizations can understand the effectiveness of their WASH activities and improve accordingly. CAWST developed this methodology through a series of research partnerships, followed by staged field pilots in Nepal, Peru, Ethiopia and Haiti. During the research partnerships, CAWST collaborated with universities in the UK and Canada to: review a range of available evaluation frameworks, investigate existing practices for evaluating education activities, and develop a draft methodology for evaluating education programs. The draft methodology was then piloted in three separate studies to evaluate CAWST’s, and CAWST’s partner’s, WASH education programs. Each of the pilot studies evaluated education programs in different locations, with different objectives, and at different times within the project cycles. The evaluations in Nepal and Peru were conducted in 2013 and investigated the outcomes and impacts of CAWST’s WASH education services in those countries over the past 5-10 years. In 2014, the methodology was applied to complete a rigorous evaluation of a 3-day WASH Awareness training program in Ethiopia, one year after the training had occurred. In 2015, the methodology was applied in Haiti to complete a rapid assessment of a Community Health Promotion program, which informed the development of an improved training program. After each pilot evaluation, the methodology was reviewed and improvements were made. A key concept within the methodology is that in order for training activities to lead to improved WASH practices at the community level, it is not enough for participants to acquire new knowledge and skills; they must also apply the new skills and influence the behavior of others following the training. The steps of the methodology include: development of a Theory of Change for the education program, application of the Kirkpatrick model to develop indicators, development of data collection tools, data collection, data analysis and interpretation, and use of the findings for improvement. The methodology was applied in different ways for each pilot and was found to be practical to apply and adapt to meet the needs of each case. It was useful in gathering specific information on the outcomes of the education and training activities, and in developing recommendations for program improvement. Based on the results of the pilot studies, CAWST is developing a set of support materials to enable other WASH implementers to apply the methodology. By using this methodology, more WASH organizations will be able to understand the outcomes and impacts of their training activities, leading to higher quality education programs and improved WASH outcomes.

Keywords: education and training, capacity building, evaluation, water and sanitation

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Authors: Afia Naheed, Manmohan Singh, David Lucy

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This work is based on a mathematical as well as statistical study of an SEIJTR deterministic model for the interpretation of transmission of severe acute respiratory syndrome (SARS). Based on the SARS epidemic in 2003, the parameters are estimated using Runge-Kutta (Dormand-Prince pairs) and least squares methods. Possible graphical and numerical techniques are used to validate the estimates. Then effect of the model parameters on the dynamics of the disease is examined using sensitivity and uncertainty analysis. Sensitivity and uncertainty analytical techniques are used in order to analyze the affect of the uncertainty in the obtained parameter estimates and to determine which parameters have the largest impact on controlling the disease dynamics.

Keywords: infectious disease, severe acute respiratory syndrome (SARS), parameter estimation, sensitivity analysis, uncertainty analysis, Runge-Kutta methods, Levenberg-Marquardt method

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