Search results for: direct and indirect tensile test

Authors: Nicola S. Schutte, John M. Malouff

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Introduction: Curiosity is a positive emotion and motivational state that consists of the desire to know. Curiosity consists of several related dimensions, including a desire for exploration, deprivation sensitivity, and stress tolerance. Creativity involves generating novel and valuable ideas or products. How curiosity may prompt greater creativity remains to be investigated. The phenomena of flow may link curiosity and creativity. Flow is characterized by intense concentration and absorption and gives rise to optimal performance. Objective of Study: The objective of the present study was to investigate whether the phenomenon of flow may link curiosity with creativity. Methods and Design: Fifty-seven individuals from Australia (45 women and 12 men, mean age of 35.33, SD=9.4) participated. Participants were asked to design a program encouraging residents in a local community to conserve water and to record the elements of their program in writing. Participants were then asked to rate their experience as they developed and wrote about their program. Participants rated their experience on the Dimensional Curiosity Measure sub-scales assessing the exploration, deprivation sensitivity, and stress tolerance facets of curiosity, and the Flow Short Scale. Reliability of the measures as assessed by Cronbach's alpha was as follows: Exploration Curiosity =.92, Deprivation Sensitivity Curiosity =.66, Stress Tolerance Curiosity =.93, and Flow=.96. Two raters independently coded each participant’s water conservation program description on creativity. The mixed-model intraclass correlation coefficient for the two sets of ratings was .73. The mean of the two ratings produced the final creativity score for each participant. Results: During the experience of designing the program, all three types of curiosity were significantly associated with the flow. Pearson r correlations were as follows: Exploration Curiosity and flow, r =.68 (higher Exploration Curiosity was associated with more flow); Deprivation Sensitivity Curiosity and flow, r =.39 (higher Deprivation Sensitivity Curiosity was associated with more flow); and Stress Tolerance Curiosity and flow, r = .44 (more stress tolerance in relation to novelty and exploration was associated with more flow). Greater experience of flow was significantly associated with greater creativity in designing the water conservation program, r =.39. The associations between dimensions of curiosity and creativity did not reach significance. Even though the direct relationships between dimensions of curiosity and creativity were not significant, indirect relationships through the mediating effect of the experience of flow between dimensions of curiosity and creativity were significant. Mediation analysis using PROCESS showed that flow linked Exploration Curiosity with creativity, standardized beta=.23, 95%CI [.02,.25] for the indirect effect; Deprivation Sensitivity Curiosity with creativity, standardized beta=.14, 95%CI [.04,.29] for the indirect effect; and Stress Tolerance Curiosity with creativity, standardized beta=.13, 95%CI [.02,.27] for the indirect effect. Conclusions: When engaging in an activity, higher levels of curiosity are associated with greater flow. More flow is associated with higher levels of creativity. Programs intended to increase flow or creativity might build on these findings and also explore causal relationships.

Keywords: creativity, curiosity, flow, motivation

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Authors: Rajesh Kumar, Puneet Aggarwal

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In context of understanding problems faced by undergraduate students while carrying out laboratory experiments dealing with high voltages, it was found that most of the students are hesitant to work directly on machine. The reason is that error in the circuitry might lead to deterioration of machine and laboratory instruments. So, it has become inevitable to include modern pedagogic techniques for undergraduate students, which would help them to first carry out experiment in virtual system and then to work on live circuit. Further advantages include that students can try out their intuitive ideas and perform in virtual environment, hence leading to new research and innovations. In this paper, virtual environment used is of MATLAB/Simulink for three-phase induction machines. The performance analysis of three-phase induction machine is carried out using virtual environment which includes Direct Current (DC) Test, No-Load Test, and Block Rotor Test along with speed torque characteristics for different rotor resistances and input voltage, respectively. Further, this paper carries out computer aided teaching of basic Voltage Source Inverter (VSI) drive circuitry. Hence, this paper gave undergraduates a clearer view of experiments performed on virtual machine (No-Load test, Block Rotor test and DC test, respectively). After successful implementation of basic tests, VSI circuitry is implemented, and related harmonic distortion (THD) and Fast Fourier Transform (FFT) of current and voltage waveform are studied.

Keywords: block rotor test, DC test, no load test, virtual environment, voltage source inverter

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Authors: Emmanuel Ogundimu, Esther Akinlabi, Mutiu Erinosho

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In this research, studies were done on the material characterization of type 304 austenitic stainless steel weld produced by TIG (Tungsten Inert Gas) and MIG (Metal Inert Gas) welding processes. This research is aimed to establish optimized process parameters that will result in a defect-free weld joint, homogenous distribution of the iron (Fe), chromium (Cr) and nickel (Ni) was observed at the welded joint of all the six samples. The welded sample produced at the current of 170 A by TIG welding process had the highest ultimate tensile strength (UTS) value of 621 MPa at the welds zone, and the welded sample produced by MIG process at the welding current of 150 A had the lowest UTS value of 568 MPa. However, it was established that TIG welding process is more appropriate for the welding of type 304 austenitic stainless steel compared to the MIG welding process.

Keywords: microhardness, microstructure, tensile, MIG welding, process, tensile, shear stress TIG welding, TIG-MIG welding

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Authors: Mouna Essaadi, Mohamed Khafallah, Abdallah Saad, Hamid Chaikhy

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This paper presents a comparative analysis between conventional direct torque control (C_DTC), Modified direct torque control (M_DTC) and twelve sectors direct torque control (12_DTC).Those different strategies are compared by simulation in term of torque, flux and stator current performances. Finally, a summary of the comparative analysis is presented.

Keywords: C_DTC, M_DTC, 12_DTC, torque dynamic, stator current, flux, performances

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Authors: Supriya Patibanda, Xiaopeng Gong, Krishna N. Jonnalagadda, Ralph Abrahams

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Yttria stabilized zirconia (YSZ) is used as a top coat in thermal barrier coatings in high-temperature turbine/jet engine applications. The mechanical behaviour of YSZ depends on the microstructural features like crack density and porosity, which are a result of coating method. However, experimentally ascertaining their individual effect is difficult due to the inherent challenges involved like material synthesis and handling. The current work deals with the development of a phenomenological model to replicate the tensile behavior of air plasma sprayed YSZ obtained from experiments. Initially, uniaxial tensile experiments were performed on freestanding YSZ coatings of ~300 µm thick for different crack densities and porosities. The coatings exhibited a nonlinear behavior and also a huge variation in strength values. With the obtained experimental tensile curve as a base and crack density and porosity as prime variables, a phenomenological model was developed using ABAQUS interface with new user material defined employing VUMAT sub routine. The relation between the tensile stress and the crack density was empirically established. Further, a parametric study was carried out to investigate the effect of the individual features on the non-linearity in these coatings. This work enables to generate new coating designs by varying the key parameters and predicting the mechanical properties with the help of a simulation, thereby minimizing experiments.

Keywords: crack density, finite element method, plasma sprayed coatings, VUMAT

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Authors: Tiberiu Socaciu, Tudor Colomeischi, Eugenia Iancu

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Business failure affects in various proportions shareholders, managers, lenders (banks), suppliers, customers, the financial community, government and society as a whole. In the era in which we have telecommunications networks, exists an interdependence of markets, the effect of a failure of a company is relatively instant. To effectively manage risk exposure is thus require sophisticated support systems, supported by analytical tools to measure, monitor, manage and control operational risks that may arise. As we know, bankruptcy is a phenomenon that managers do not want no matter what stage of life is the company they direct / lead. In the analysis made by us, by the nature of economic models that are reviewed (Altman, Conan-Holder etc.), estimating the risk of bankruptcy of a company corresponds to some extent with its own business cycle tracing of the company. Various models for predicting bankruptcy take into account direct / indirect aspects such as market position, company growth trend, competition structure, characteristics and customer retention, organization and distribution, location etc. From the perspective of our research we will now review the economic models known in theory and practice for estimating the risk of bankruptcy; such models are based on indicators drawn from major accounting firms.

Keywords: Anglo-Saxon models, continental models, national models, statistical models

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Authors: Salihu Takuma

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Neem seed oil has high contents of unsaturated fatty acids which can be converted to epoxy fatty acids. The vegetable oil – based epoxy material are sustainable, renewable and biodegradable materials replacing petrochemical – based epoxy materials in some applications. Polystyrene is highly brittle with limited mechanical applications. Raw neem seed oil was obtained from National Research Institute for Chemical Technology (NARICT), Zaria, Nigeria. The oil was epoxidized at 60 0C for three (3) hours using formic acid generated in situ. The epoxidized oil was characterized using Fourier Transform Infrared spectroscopy (FTIR). The disappearance of C = C stretching peak around 3011.7 cm-1and formation of a new absorption peak around 943 cm-1 indicate the success of epoxidation. The epoxidized oil was blended with pure polystyrene in different weight percent compositions using solution casting in chloroform. The tensile properties of the blends demonstrated that the addition of 5 wt % ENO to PS led to an increase in elongation at break, but a decrease in tensile strength and modulus. This is in accordance with the common rule that plasticizers can decrease the tensile strength of the polymer.

Keywords: biodegradable, elongation at break, epoxidation, epoxy fatty acids, sustainable, tensile strength and modulus

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Authors: Amnon Shirizly, Ohad Dolev

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In recent years, the implementation and use of Metal Additive Manufacturing (AM) parts increase. As a result, the demand for bigger parts rises along with the desire to reduce it’s the production cost. Generally, in powder bed Additive Manufacturing technology the part size is limited by the machine build volume. In order to overcome this limitation, the parts can be built in one or more machine operations and mechanically joint or weld them together. An alternative option could be a production of wrought part and built on it the AM structure (mainly to reduce costs). In both cases, the mechanical properties of the interface have to be defined and recognized. In the current study, the authors introduce guidelines on how to examine the interface between wrought alloy and powder-bed AM. The mechanical and metallurgical properties of the Ti6Al4V materials (wrought alloy and powder-bed AM) and their hybrid interface were examined. The mechanical properties gain from tensile test bars in the built direction and fracture toughness samples in various orientations. The hybrid specimens were built onto a wrought Ti6Al4V start-plate. The standard fracture toughness (CT25 samples) and hybrid tensile specimens' were heat treated and milled as a post process to final diminutions. In this Study, the mechanical tensile tests and fracture toughness properties supported by metallurgical observation will be introduced and discussed. It will show that the hybrid approach of utilizing powder bed AM onto wrought material expanding the current limitation of the future manufacturing technology.

Keywords: additive manufacturing, hybrid, fracture-toughness, powder bed

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Authors: B. Vinod, L. Jsudev

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Natural fibers as reinforcement in polymer matrix material is gaining lot of attention in recent years, as they are light in weight, less in cost, and ecologically advanced surrogate material to glass and carbon fibers in composites. Natural fibers like jute, sisal, coir, hemp, banana etc. have attracted substantial importance as a potential structural material because of its attractive features along with its good mechanical properties. Cryogenic applications of natural fiber reinforced polymer composites like cryogenic wind tunnels, cryogenic transport vessels, support structures in space shuttles and rockets are gaining importance. In these unique cryogenic applications, the requirements of polymer composites are extremely severe and complicated. These materials need to possess good mechanical and physical properties at cryogenic temperatures such as liquid helium (4.2 K), liquid hydrogen (20 K), liquid nitrogen (77 K), and liquid oxygen (90 K) temperatures, etc., to meet the high requirements by the cryogenic engineering applications. The objective of this work is to investigate the mechanical behavior of hybrid hemp/jute fibers reinforced epoxy composite material at liquid nitrogen temperature. Hemp and Jute fibers are used as reinforcement material as they have high specific strength, stiffness and good adhering property and has the potential to replace the synthetic fibers. Hybrid hemp/jute fibers reinforced polymer composite is prepared by hand lay-up method and test specimens are cut according to ASTM standards. These test specimens are dipped in liquid nitrogen for different time durations. The tensile properties, flexural properties and impact strength of the specimen are tested immediately after the specimens are removed from liquid nitrogen container. The experimental results indicate that the cryogenic treatment of the polymer composite has a significant effect on the mechanical properties of this material. The tensile properties and flexural properties of the hybrid hemp/jute fibers epoxy composite at liquid nitrogen temperature is higher than at room temperature. The impact strength of the material decreased after subjecting it to liquid nitrogen temperature.

Keywords: liquid nitrogen temperature, polymer composite, tensile properties, flexural properties

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Authors: Youn-Sung Kim, Jin-Ho Jo, Mi-Sung Kim, Jae-Kun Lee

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Accelerated life cycle test is applied to various products or components in order to reduce the time of life cycle test in industry. It must be considered for many test conditions according to the product characteristics for the test and the selection of acceleration parameter is especially very important. We have carried out the general life cycle test and the accelerated life cycle test by applying the acceleration factor (AF) considering the characteristics of brushless DC (BLDC) motor for washing machine. The final purpose of this study is to verify the validity by analyzing the results of the general life cycle test and the accelerated life cycle test. It will make it possible to reduce the life test time through the reasonable accelerated life cycle test.

Keywords: accelerated life cycle test, reliability test, motor for washing machine, brushless dc motor test

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Authors: Anne Schattel, Mitja Echim, Christof Büskens

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Trajectory planning for deep space missions has become a recent topic of great interest. Flying to space objects like asteroids provides two main challenges. One is to find rare earth elements, the other to gain scientific knowledge of the origin of the world. Due to the enormous spatial distances such explorer missions have to be performed unmanned and autonomously. The mathematical field of optimization and optimal control can be used to realize autonomous missions while protecting recourses and making them safer. The resulting algorithms may be applied to other, earth-bound applications like e.g. deep sea navigation and autonomous driving as well. The project KaNaRiA ('Kognitionsbasierte, autonome Navigation am Beispiel des Ressourcenabbaus im All') investigates the possibilities of cognitive autonomous navigation on the example of an asteroid mining mission, including the cruise phase and approach as well as the asteroid rendezvous, landing and surface exploration. To verify and test all methods an interactive, real-time capable simulation using virtual reality is developed under KaNaRiA. This paper focuses on the specific challenge of the guidance during the cruise phase of the spacecraft, i.e. trajectory optimization and optimal control, including first solutions and results. In principle there exist two ways to solve optimal control problems (OCPs), the so called indirect and direct methods. The indirect methods are being studied since several decades and their usage needs advanced skills regarding optimal control theory. The main idea of direct approaches, also known as transcription techniques, is to transform the infinite-dimensional OCP into a finite-dimensional non-linear optimization problem (NLP) via discretization of states and controls. These direct methods are applied in this paper. The resulting high dimensional NLP with constraints can be solved efficiently by special NLP methods, e.g. sequential quadratic programming (SQP) or interior point methods (IP). The movement of the spacecraft due to gravitational influences of the sun and other planets, as well as the thrust commands, is described through ordinary differential equations (ODEs). The competitive mission aims like short flight times and low energy consumption are considered by using a multi-criteria objective function. The resulting non-linear high-dimensional optimization problems are solved by using the software package WORHP ('We Optimize Really Huge Problems'), a software routine combining SQP at an outer level and IP to solve underlying quadratic subproblems. An application-adapted model of impulsive thrusting, as well as a model of an electrically powered spacecraft propulsion system, is introduced. Different priorities and possibilities of a space mission regarding energy cost and flight time duration are investigated by choosing different weighting factors for the multi-criteria objective function. Varying mission trajectories are analyzed and compared, both aiming at different destination asteroids and using different propulsion systems. For the transcription, the robust method of full discretization is used. The results strengthen the need for trajectory optimization as a foundation for autonomous decision making during deep space missions. Simultaneously they show the enormous increase in possibilities for flight maneuvers by being able to consider different and opposite mission objectives.

Keywords: deep space navigation, guidance, multi-objective, non-linear optimization, optimal control, trajectory planning.

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Authors: S. D. El Wakil

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The research work reported here was aimed at investigating the feasibility of joining high-porosity stainless steel discs and wrought iron bars by friction welding. The sound friction-welded joints were then subjected to a metallurgical investigation and an analysis of failure resulting from tensile loading. Discs having 50 mm diameter and 10 mm thickness were produced by loose sintering of stainless steel powder at a temperature of 1350 ^oC in an argon atmosphere for one hour. Minor machining was then carried out to control the dimensions of the discs, and the density of each disc could then be determined. The level of porosity was calculated and was found to be about 40% in all of those discs. Solid wrought iron bars were also machined to facilitate tensile testing of the joints produced by friction welding. Using our previously gained experience, the porous stainless steel disc and the wrought iron tube were successfully friction welded. SEM was employed to examine the fracture surface after a tensile test of the joint in order to determine the type of failure. It revealed that the failure did not occur in the joint, but rather in the in the porous metal in the area adjacent to the joint. The load carrying capacity was actually determined by the strength of the porous metal and not by that of the welded joint. Macroscopic and microscopic metallographic examinations were also performed and showed that the welded joint involved a dense heat-affected zone where the porous metal underwent densification at elevated temperature, explaining and supporting the findings of the SEM study.

Keywords: fracture of friction-welded joints, metallurgy of friction welding, solid-porous structures, strength of joints

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Authors: Amar Boukerrou, Ouerdia Belhadj, Dalila Hammiche, Jean Francois Gerard, Jannick Rumeau

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The main goal of this study is the investigation of alfa fiber content, treated with alkali treatment, on the thermal and mechanical properties of epoxy-amine matrix-based composites. The fibers were treated with 5% of sodium hydroxide solution and varied between 10% to 30% weight fractions. The tensile, flexural, and hardness tests are carried out to investigate the mechanical properties of composites. The results show those composites’ mechanical properties are higher than the neat epoxy-amine. It was noticed that the alkali treatment is more effective in the case of the tensile and flexural modulus than the tensile and flexural strength. The decline of both the tensile and flexural behavior of all composites with the increasing of the filler content was due probably to the random dispersion of the fibers in the epoxy resin The Fourier transform infrared (FTIR) was employed to analyze the chemical structure of epoxy resin before and after curing with amine hardener. FTIR and DSC analysis confirmed that epoxy resin was completely cured with amine hardener at room temperature. SEM analysis has highlighted the microstructure of epoxy matrix and its composites.

Keywords: alfa fiber, epoxy resin, alkali treatment, mechanical properties

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Authors: Llham Lhoume, Rachid Tadili, Nora Arbaoui

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One of the most crucial ways to combat food insecurity is to minimize crop losses, food drying is one of the most organic, effective, low-cost and energy-efficient food preservation methods. In this regard, we undertake in this study an experimental evaluation and analysis of the thermal performance of different natural convection drying systems: a solar greenhouse dryer, an indirect solar dryer with a single compartment and a solar dryer with two compartments. These systems have been implemented at the Solar Energy and Environment Laboratory of Mohammed V University (Morocco). The objective of this work is to study the feasibility of converting a solar greenhouse into a solar dryer for use during the summer. On the other hand, to study the thermal performances of this greenhouse dryer by comparing it with other solar dryers. The experimental study showed that the drying of verbena leaves took 6 hours in the indirect dryer 1, 3 hours in the indirect dryer, 2 and 4 hours in the greenhouse dryer, but the amortization period of the solar greenhouse dryer is lower than the other two solar dryers. The results of this study provide key information on the implementation and performance of these systems for drying a food of great global interest.

Keywords: solar energy, drying, agriculture, biotechnologie

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Authors: Xiaohuan Li, Wangmin Yi, Xinghui Wu

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In order to verify the performance of lunar lander structure, landing-impact test is urgently needed. Moreover, the test equipment is necessary for the test. The functions and the key points of the equipment is presented to satisfy the requirements of the test，and the design scheme is proposed. The composition, the major function and the critical parts’ design of the equipment are introduced. By the load test of releasing device and single-beam hoist, and the compatibility test of landing-impact testing system, the rationality and reliability of the equipment is proved.

Keywords: landing-impact test, lunar lander, releasing device, test equipment

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Authors: Manamba Epaphra

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This paper analyzes the causal effect between domestic private investment, public investment, foreign direct investment and economic growth in Tanzania during the 1970-2014 period. The modified neo-classical growth model that includes control variables such as trade liberalization, life expectancy and macroeconomic stability proxied by inflation is used to estimate the impact of investment on economic growth. Also, the economic growth models based on Phetsavong and Ichihashi (2012), and Le and Suruga (2005) are used to estimate the crowding out effect of public investment on private domestic investment on one hand and foreign direct investment on the other hand. A correlation test is applied to check the correlation among independent variables, and the results show that there is very low correlation suggesting that multicollinearity is not a serious problem. Moreover, the diagnostic tests including RESET regression errors specification test, Breusch-Godfrey serial correlation LM test, Jacque-Bera-normality test and white heteroskedasticity test reveal that the model has no signs of misspecification and that, the residuals are serially uncorrelated, normally distributed and homoskedastic. Generally, the empirical results show that the domestic private investment plays an important role in economic growth in Tanzania. FDI also tends to affect growth positively, while control variables such as high population growth and inflation appear to harm economic growth. Results also reveal that control variables such as trade openness and life expectancy improvement tend to increase real GDP growth. Moreover, a revealed negative, albeit weak, association between public and private investment suggests that the positive effect of domestic private investment on economic growth reduces when public investment-to-GDP ratio exceeds 8-10 percent. Thus, there is a great need for promoting domestic saving so as to encourage domestic investment for economic growth.

Keywords: FDI, public investment, domestic private investment, crowding out effect, economic growth

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Authors: Amin Kaveh Boukani

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Foreign language learning is not straightforward and can be affected by numerous factors, among which personality features like tolerance of ambiguity (TA) are so well-known and important. Such characteristics yet can be affected by other factors like learning additional languages. The current investigation, thus, opted to explore the possible effect of linguistic background (being bilingual or trilingual) on the tolerance of ambiguity (TA) of Iranian EFL learners. Furthermore, the possible mediating effect of TA on multilingual learners' language performance (listening comprehension in this study) was expounded. This research involved 68 EFL learners (32 bilinguals, 29 trilinguals) with the age range of 19-29 doing their degrees in the Department of English Language and Literature of Urmia University. A set of questionnaires, including tolerance of ambiguity (Herman et. al., 2010) and linguistic background information (Modirkhameneh, 2005), as well as the IELTS listening comprehension test, were used for data collection purposes. The results of a set of independent samples t-test and mediation analysis (Hayes, 2022) showed that (1) linguistic background (being bilingual or trilingual) had a significant direct effect on EFL learners' TA, (2) Linguistic background had a significant direct influence on listening comprehension, (3) TA had a substantial direct influence on listening comprehension, and (4) TA moderated the influence of linguistic background on listening comprehension considerably. These results suggest that multilingualism may be considered as an advantageous asset for EFL learners and should be a prioritized characteristic in EFL instruction in multilingual contexts. Further pedagogical implications and suggestions for research are proposed in light of effective EFL instruction in multilingual contexts.

Keywords: tolerance of ambiguity, listening comprehension, multilingualism, bilingual, trilingual

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Authors: Anthony Credoz, Nathalie Nief, Remy Hedacq, Salvador Jordana, Laurent Cazes

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Groundwater monitoring is classically performed in a network of piezometers in industrial sites. Groundwater flow parameters, such as direction, sense and velocity, are deduced from indirect measurements between two or more piezometers. Groundwater sampling is generally done on the whole column of water inside each borehole to provide concentration values for each piezometer location. These flow and concentration values give a global ‘static’ image of potential plume of contaminants evolution in the shallow aquifer with huge uncertainties in time and space scales and mass discharge dynamic. TOTAL R&D Subsurface Environmental team is challenging this classical approach with an innovative dynamic way of characterization of shallow aquifer groundwater. The current study aims at optimizing the tools and methodologies for (i) a direct and multilevel measurement of groundwater velocities in each piezometer and, (ii) a calculation of potential flux of dissolved contaminant in the shallow aquifer. Lab-scale experiments have been designed to test commercial and R&D tools in a controlled sandbox. Multiphysics modeling were performed and took into account Darcy equation in porous media and Navier-Stockes equation in the borehole. The first step of the current study focused on groundwater flow at porous media/piezometer interface. Huge uncertainties from direct flow rate measurements in the borehole versus Darcy flow rate in the porous media were characterized during experiments and modeling. The structure and location of the tools in the borehole also impacted the results and uncertainties of velocity measurement. In parallel, direct-push tool was tested and presented more accurate results. The second step of the study focused on mass flux of dissolved contaminant in groundwater. Several active and passive commercial and R&D tools have been tested in sandbox and reactive transport modeling has been performed to validate the experiments at the lab-scale. Some tools will be selected and deployed in field assays to better assess the mass discharge of dissolved contaminants in an industrial site. The long-term subsurface environmental strategy is targeting an in-situ, real-time, remote and cost-effective monitoring of groundwater.

Keywords: dynamic characterization, groundwater flow, lab-scale, mass flux

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Authors: Jingwen Ou

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Writing for academic purposes in a second or foreign language is one of the most important and the most demanding skills to be mastered by non-native speakers. Traditionally, the EAP writing instruction at the tertiary level encompasses the teaching of academic genre knowledge, more specifically, the disciplinary writing conventions, the rhetorical functions, and specific linguistic features. However, one of the main sources of challenges in English academic writing for L2 students at the tertiary level can still be found in proficiency in academic discourse, especially vocabulary, academic register, and organization. Data-Driven Learning (DDL) is defined as “a pedagogical approach featuring direct learner engagement with corpus data”. In the past two decades, the rising popularity of the application of the data-driven learning (DDL) approach in the field of EAP writing teaching has been noticed. Such a combination has not only transformed traditional pedagogy aided by published DDL guidebooks in classroom use but also triggered global research on corpus use in EAP classrooms. This study endeavors to delineate a systematic review of research in the intersection of DDL and EAP writing instruction by conducting a systematic literature review on both indirect and direct DDL practice in EAP writing instructional settings in China. Furthermore, the review provides a synthesis of significant discoveries emanating from prior research investigations concerning Chinese university students’ perception of Data-Driven Learning (DDL) and the subsequent impact on their academic writing performance following corpus-based training. Research papers were selected from Scopus-indexed journals and core journals from two main Chinese academic databases (CNKI and Wanfang) published in both English and Chinese over the last ten years based on keyword searches. Results indicated an insufficiency of empirical DDL research despite a noticeable upward trend in corpus research on discourse analysis and indirect corpus applications for material design by language teachers. Research on the direct use of corpora and corpus tools in DDL, particularly in combination with genre-based EAP teaching, remains a relatively small fraction of the whole body of research in Chinese higher education settings. Such scarcity is highly related to the prevailing absence of systematic training in English academic writing registers within most Chinese universities' EAP syllabi due to the Chinese English Medium Instruction policy, where only English major students are mandated to submit English dissertations. Findings also revealed that Chinese learners still held mixed attitudes towards corpus tools influenced by learner differences, limited access to language corpora, and insufficient pre-training on corpus theoretical concepts, despite their improvements in final academic writing performance.

Keywords: corpus linguistics, data-driven learning, EAP, tertiary education in China

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Authors: Shuhong Wang, Xiang Yi

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Through a survey of approximately 340 employees from four Chinese companies and employing cross-level analysis, this study reveals that certain cultural syndromes may exert both direct and indirect influences on such behaviors. Notably, individuals with a strong individualistic self-concept are more inclined towards innovative actions compared to their less individualistic counterparts. This research also identifies several moderating factors. For instance, trust amplifies the positive relationship between individualism and innovative actions, particularly at higher trust levels. The paper concludes by highlighting its theoretical contributions, and practical implications, and suggesting directions for future research.

Keywords: Innovation, Self-Determination Theory, Trust, Team dynamic, Allocentrism

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Authors: S. Chandrakaran, G. Govind

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Stone columns are effectively used to improve bearing strength of soils and also for many geotechnical applications. In soft soils when stone columns are loaded they undergo large settlements due to insufficient lateral confinement. Use of geosynthetics encasement has proved to be a solution for this problem. In this paper, results of a laboratory experimental study carried out with model stone columns with and without encasement. Sand was used for making test beds, and grain size of soil varies from 0.075mm to 4.75mm. Woven geotextiles produced by Gareware ropes India with mass per unit area of 240gm/M2 and having tensile strength of 52KN/m is used for the present investigation. Tests were performed with large scale direct shear box and also using scaled laboratory plate load tests. Stone column of 50mm and 75mm is used for the present investigation. Diameter of stone column, size of stones used for making stone columns is varied in making stone column in the present study. Two types of stone were used namely small and bigger in size. Results indicate that there is an increase in angle of internal friction and also an increase in the shear strength of soil when stone columns are encased. With stone columns with 50mm dia, an average increase of 7% in shear strength and 4.6 % in angle of internal friction was achieved. When large stones were used increase in the shear strength was 12.2%, and angle of internal friction was increased to 5.4%. When the stone column diameter has increased to 75mm increase in shear strength and angle of internal friction was increased with smaller size of stones to 7.9 and 7.5%, and with large size stones, it was 7.7 and 5.48% respectively. Similar results are obtained in plate load tests, also.

Keywords: stone columns, encasement, shear strength, plate load test

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Authors: Laurisa Peters, Usha Barahmand, Maria Stalias-Mantzikos, Naila Shamsina, Kerry Aguero

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In the current study, the authors sought to examine whether the links between moral and sexual disgust and misophonia are mediated by mental contamination. An internationally diverse sample of 283 adults (193 females, 76 males, and 14 non-binary individuals) ranging in age from 18 to 60 years old was recruited from online social media platforms and survey recruitment sites. The sample completed an online battery of scales that consisted of the New York Misophonia Scale, State Mental Contamination Scale, and the Three-Domain Disgust Scale. The hypotheses were evaluated using a series of mediations performed using the PROCESS add-on in SPSS. Correlations were found between emotional and aggressive-avoidant reactions in misophonia, mental contamination, pathogen disgust, and sexual disgust. Moral disgust and non-aggressive reactions in misophonia failed to correlate significantly with any of the other constructs. Sexual disgust had direct and indirect effects, while pathogen disgust had only direct effects on aspects of misophonia. These findings partially support our hypothesis that mental contamination mediates the link between disgust propensity and misophonia while also confirming that pathogen-based disgust is not associated with mental contamination. Findings imply that misophonia is distinct from obsessive-compulsive disorder. Further research into the conceptualization of moral disgust is warranted.

Keywords: misophonia, moral disgust, pathogen disgust, sexual disgust, mental contamination

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Authors: Dandi Bachtiar, Mohammed Ausama Abbas, Januar Parlaungan Siregar, Mohd Ruzaimi Bin Mat Rejab

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Short sugar palm fibre and thermoplastic polyurethane were combined to produce new composites by using the extrude method. Two techniques used to prepare a new composite material, firstly, extrusion of the base material with short fibre, secondly hot pressing them. The size of sugar palm fibre was fixed at 250µm. Different weight percent (10 wt%, 20 wt% and 30 wt%) were used in order to optimise preparation process. The optimization of process depended on the characterization mechanical properties such as impact, tensile, and flexural of the new (TPU/SPF) composite material. The results proved that best tensile and impact properties of weight additive fibre applied 10 wt%. There was an increasing trend recorded of flexural properties during increased the fibre loading. Meanwhile, the maximum tensile strength was 14.0 MPa at 10 wt% of the fibre. Moreover, there was no significant effect for additions more than 30 wt% of the fibre.

Keywords: composites, natural fibre, polyurethane, sugar palm

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Authors: Aleš Florian, Lenka Ševelová, Jaroslav Žák

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Formation of tensile cracks in concrete slabs of rigid pavement can be (among others) the initiation point of the other, more serious failures which can ultimately lead to complete degradation of the concrete slab and thus the whole pavement. Two measures can be used for reliability assessment of this phenomenon - the probability of failure and/or the reliability index. Different methods can be used for their calculation. The simple ones are called moment methods and simulation techniques. Two methods - FOSM Method and Simple Random Sampling Method - are verified and their comparison is performed. The influence of information about the probability distribution and the statistical parameters of input variables as well as of the limit state function on the calculated reliability index and failure probability are studied in three points on the lower surface of concrete slabs of the older type of rigid pavement formerly used in the Czech Republic.

Keywords: failure, pavement, probability, reliability index, simulation, tensile crack

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Authors: Ovidiu Domşa, Nicolae Bold

Abstract:

Using Information and Communication Technologies (ICT) notions in education and three basic processes of education (teaching, learning and assessment) can bring benefits to the pupils and the professional development of teachers. In this matter, we refer to these notions as concepts taken from the informatics area and apply them to the domain of education. These notions refer to genetic algorithms and arborescent structures, used in the specific process of assessment or evaluation. This paper uses these kinds of notions to generate subtrees from a main tree of tests related between them by their degree of difficulty. These subtrees must contain the highest number of connections between the nodes and the lowest number of missing edges (which are subtrees of the main tree) and, in the particular case of the non-existence of a subtree with no missing edges, the subtrees which have the lowest (minimal) number of missing edges between the nodes, where a node is a test and an edge is a direct connection between two tests which differs by one degree of difficulty. The subtrees are represented as sequences. The tests are the same (a number coding a test represents that test in every sequence) and they are reused for each sequence of tests.

Keywords: chromosome, genetic algorithm, subtree, test

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Authors: Nur Zahidah Rozaki, Desmond Ang Teck Chye

Abstract:

Environment-friendly polymeric plasticisers for poly(vinyl chloride), PVC were synthesised using palm oil as the main raw material. The synthesis comprised of 2 steps: (i) transesterification of palm oil, followed by (ii) polycondensation between the products of transesterification with diacids. The synthesis involves four different formulations to produce plasticisers with different average molecular weight. Chemical structures of the plasticiser were studied using FTIR (Fourier-Transformed Infra-Red) and 1H-NMR (Proton-Nuclear Magnetic Resonance).The molecular weights of these palm oil-based polymers were obtained using GPC (Gel Permeation Chromatography). PVC was plasticised with the polymeric plasticisers through solvent casting technique using tetrahydrofuran, THF as the mutual solvent. Some of the tests conducted to evaluate the effectiveness of the plasticiser in the PVC film including thermal stability test using thermogravimetric analyser (TGA), differential scanning calorimetry (DSC) analysis to determine the glass transition temperature, Tg, and mechanical test to determine tensile strength, modulus and elongation at break of plasticised PVC using standard test method ASTM D882.

Keywords: alkyd, palm oil, plasticiser, pvc

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Authors: Hend Almaseb

Abstract:

Child aggression is a serious social problem that affects children’s lives. This study examines the relationship between three types of aggressive behaviors–physical, verbal, and indirect aggression–from sociocultural and social work perspectives. Also, it investigates the effect of gender on the three types of aggressive behaviors and the most frequently used aggressive behaviors among a sample of 329 Kuwaiti children. The results show that there is a positive correlation between the three types of aggression and gender.

Keywords: child aggression, indirect aggression, physical aggression, verbal aggression

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Authors: Emin Çadirli, Izzettin Yilmazer, Uğur Büyük, Hasan Kaya

Abstract:

Al-2Mn-5Fe eutectic alloy (wt.%) was prepared in a graphite crucible under vacuum atmosphere. The samples were directionally solidified upward at a constant temperature gradient in four different of growth rates by using a Bridgman method. The values of eutectic spacing were measured from longitudinal and transverse sections of the samples. The dependence of eutectic spacing on the growth rate was determined by using linear regression analysis. The microhardness and tensile strength of the studied alloy also were measured from directionally solidified samples. The dependency of the microhardness and tensile strength for directionally solidified Al-2Mn-5Fe eutectic alloy on the growth rate were investigated and the relationships between them were experimentally obtained by using regression analysis. The results obtained in present work were compared with the previous similar experimental results obtained for binary and ternary alloys.

Keywords: eutectic alloy, microhardness, microstructure, tensile strength

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Authors: A. Lakshumu Naidu, K. Krishna Kishor

Abstract:

This paper examines the results of an experimental study based on the engineering properties of banana peel reinforced epoxy composites. Experiments are carried out to study the effect of weight fraction on mechanical behavior of epoxy based polymer composites. The composites were made by varying the weight fraction of banana peel from 0 to 30% and banana peel were made using hand layup method. The fabricated composite samples were cut according to the ASTM standards for different experiments. Hardness test and density test were carried out at the samples. The maximum hardness, density, tensile strength, flexural strength and ILSS are getting for the material prepared with the 20 % reinforced banana peel epoxy composite. The detailed test results and observations are discussed sequentially in the paper.

Keywords: engineering properties, polymer, composite, mechanical behavior of banana peel

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Authors: Huijuan Liu, Fukun Li, Hao Yuan

Abstract:

The bolted spherical node is a common type of joint in space steel structures. The bolt-sphere joint portion almost always controls the bearing capacity of the bolted spherical node. The investigation of the bearing performance and progressive failure in service often requires high-fidelity numerical models. This paper focuses on the constitutive models of bolt steel and sphere steel used in China’s space structure construction. The elastoplastic model is determined by a standard tensile test and calibrated Voce saturated hardening rule. The ductile damage is found dominant based on the fractography analysis. Then Rice-Tracey ductile fracture rule is selected and the model parameters are calibrated based on tensile tests of notched specimens. These calibrated material models can benefit research or engineering work in similar fields.

Keywords: bolt-sphere joint, steel, constitutive model, ductile damage, model calibration

Procedia PDF Downloads 116