Search results for: uniaxial tensile test
8101 Numerical and Experimental Analysis of Stiffened Aluminum Panels under Compression
Authors: Ismail Cengiz, Faruk Elaldi
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Within the scope of the study presented in this paper, load carrying capacity and buckling behavior of a stiffened aluminum panel designed by adopting current ‘buckle-resistant’ design application and ‘Post –Buckling’ design approach were investigated experimentally and numerically. The test specimen that is stabilized by Z-type stiffeners and manufactured from aluminum 2024 T3 Clad material was test under compression load. Buckling behavior was observed by means of 3 – dimensional digital image correlation (DIC) and strain gauge pairs. The experimental study was followed by developing an efficient and reliable finite element model whose ability to predict behavior of the stiffened panel used for compression test is verified by compering experimental and numerical results in terms of load – shortening curve, strain-load curves and buckling mode shapes. While finite element model was being constructed, non-linear behaviors associated with material and geometry was considered. Finally, applicability of aluminum stiffened panel in airframe design against to composite structures was evaluated thorough the concept of ‘Structural Efficiency’. This study reveals that considerable amount of weight saving could be gained if the concept of ‘post-buckling design’ is preferred to the already conventionally used ‘buckle resistant design’ concept in aircraft industry without scarifying any of structural integrity under load spectrum.Keywords: post-buckling, stiffened panel, non-linear finite element method, aluminum, structural efficiency
Procedia PDF Downloads 1498100 Tribological Behavior of EP Additives with Different Percentage of Sulfur
Authors: Salete Martins Alves, José Josemar de Oliveira Junior
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The current efforts on design of lubricants are based in attending the new requirement of modern equipment with the focus on the choice of base oil and additives. Nowadays, there are different types of lubricant oils’ bases, such as mineral oils, synthetic oils, re-refined oils and vegetable oils. The lubrication in the boundary condition is controlled mainly by EP additives that interact with the surface forming very thin films. Therefore, the study’s goal is to evaluate the action of three EP additives, with different percentage of sulfur, on friction and wear reduction. They were evaluated in mineral and synthetic oils. Lubricants were prepared with synthetic and mineral oils and added 3 % and 5 % of EP additives. The friction and wear characteristics were studied using HFRR test. In this test, a normal load of 10 N was applied at a frequency of 20 Hz. The analysis of results has appointed that the percentage of sulfur in mineral oil has influenced on wear reduction. However, synthetic oil had good performance with low sulfur content.Keywords: boundary lubrication, EP additives, sulfur, wear
Procedia PDF Downloads 4068099 Evaluation of Engineering Cementitious Composites (ECC) with Different Percentage of Fibers
Authors: Bhaumik Merchant, Ajay Gelot
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Concrete is good in compression but if any type of strain applied to it, it starts to fail. Where the steel is good tension, it can bear the deflection up to its elastic limits. This project is based on behavior of engineered cementitious composited (ECC) when it is replaced with the different amount of Polyvinyl Alcohol (PVA) Fibers. As for research, PVA fibers is used with cementitious up to 2% to evaluate the optimum amount of fiber on which we can find the maximum compressive, tensile and flexural strength. PVA is basically an adhesive which is used to formulate glue. Generally due to excessive loading, cracks develops which concludes to successive damage to the structural component. In research plasticizer is used to increase workability. With the help of optimum amount of PVA fibers, it can limit the crack widths up to 60µm to 100µm. Also can be used to reduce resources and funds for rehabilitation of structure. At the starting this fiber concrete can be double the cost as compare to conventional concrete but as it can amplify the duration of structure, it will be less costlier than the conventional concrete.Keywords: compressive strength, engineered cementitious composites, flexural strength, polyvinyl alcohol fibers, rehabilitation of structures
Procedia PDF Downloads 2918098 Utilization of Treated Spend Pot Lining by Product from the Primary Aluminum Production in Cement and Concrete
Authors: Hang Tran, Victor Brial, Luca Sorelli, Claudiane Ouellet-Plamondon, David Conciatori, Laurent Birry
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Spend pot lining (SPL) is a by-product generated from primary aluminum production. SPL consists of two parts, the first cut is rich in carbonaceous materials, and the second cut is rich in aluminum and silicon oxides. After treating by the hydrometallurgical Low Caustic Leaching and Liming process, the refractory part of SPL becomes an inert material, called LCLL ash in this project. LCLL ash was calcined at different temperatures (800 and 1000°C) and Calcined LCLL ash ground as fines of cement and replacement a part of cement in concrete production. The effect of LCLL ash on the chemical properties, mechanical properties and fresh behavior of concrete was evaluated by isothermal calorimetry, compressive test, and slump test. These results were compared to the reference mixture.Keywords: spend pot lining, concrete, cement, compressive strength, calorimetry
Procedia PDF Downloads 2228097 Factors Controlling Durability of Some Egyptian Non-Stylolitic Marbleized Limestone to Salt Weathering
Authors: H. El Shayab, G. M. Kamh, N. G. Abdel Ghafour, M. L. Abdel Latif
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Nowadays, marbleized limestone becomes one of the most important sources of the mineral wealth in Egypt as they have beautiful colors (white, grey, rose, yellow and creamy, etc.) make it very suitable for decoration purposes. Non-styolitic marbleized limestone which not contains styolitic surfaces. The current study aims to study different factors controlling durability of non-styolitic marbleized limestone against salt crystallization weathering. The achievement aim of the research was required nine representative samples were collected from the studied areas. Three samples from each of the studied areas. The studied samples was characterized by various instrumental methods before salt weathering, to determine its mineralogical composition, chemical composition and pore physical properties respectively. The obtained results revealed that both of Duwi and Delga studied samples nearly have the same average ∆M% 1.63 and 1.51 respectively and consequently A.I. stage of deformation. On the other hand, average ∆M% of Wata studied samples is 0.29 i.e. lower than two other studied areas. Wata studied samples are more durable against salt crystallization test than Duwi and Delga. The difference in salt crystallization durability may be resulted from one of the following factors: Microscopic textural effect as both of micrite and skeletal percent are in directly proportional to durability of stones to salt weathering. Dolomite mineral present as a secondary are in indirectly proportional to durability of stones to salt weathering. Increase in MgO% also associated with decrease the durability of studied samples against salt crystallization test. Finally, all factors affecting positively against salt crystallization test presents in Wadi Wata studied samples rather than others two areas.Keywords: marbleized limestone, salt weathering, Wata, salt weathering
Procedia PDF Downloads 3298096 Unit Root Tests Based On the Robust Estimator
Authors: Wararit Panichkitkosolkul
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The unit root tests based on the robust estimator for the first-order autoregressive process are proposed and compared with the unit root tests based on the ordinary least squares (OLS) estimator. The percentiles of the null distributions of the unit root test are also reported. The empirical probabilities of Type I error and powers of the unit root tests are estimated via Monte Carlo simulation. Simulation results show that all unit root tests can control the probability of Type I error for all situations. The empirical power of the unit root tests based on the robust estimator are higher than the unit root tests based on the OLS estimator.
Keywords: autoregressive, ordinary least squares, type i error, power of the test, Monte Carlo simulation
Procedia PDF Downloads 2898095 In situ Polymerization and Properties of Biobased Polyurethane/Epoxy Interpenetrating Network Nanocomposites
Authors: Aiswarea Mathew, Smita Mohanty, Jr., S. K. Nayak
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Polyurethane networks based on castor oil (CO) as a renewable resource polyol were synthesized. Polyurethane/epoxy resin interpenetrating network nanocomposites containing modified montmorillonite organoclay (C30B-PU/EP nanocomposites) were prepared by an in situ intercalation method. The conventional spectroscopic characterization of the synthesized samples using FT-IR confirms the existence of the proposed castor oil based PU structure and also showed that strong interactions existed between C30B and EP/PU matrix. The dispersion degree of C30B in EP/PU matrix was characterized by X-Ray diffraction (XRD) method. Scanning electronic microscopy analysis showed that the interpenetrating process of PU and EP increases the exfoliation degree of C30B, and it improves the compatibility and the phase structure of polyurethane/epoxy resin interpenetrating polymer networks (PU/EP IPNs). The thermal stability improves compared to the polyurethane when the PU/EP IPN is formed. Mechanical properties including the Young’s modulus and tensile strength reflected marked improvement with addition of C30B.Keywords: castor oil, epoxy, montmorillonite, polyurethane
Procedia PDF Downloads 4028094 Characterization of Mechanical Properties of Graphene-Modified Epoxy Resin for Pipeline Repair
Authors: Siti Nur Afifah Azraai, Lim Kar Sing, Nordin Yahaya, Norhazilan Md Noor
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This experimental study consists of a characterization of epoxy grout where an amount of 2% of graphene nanoplatelets particles were added to commercial epoxy resin to evaluate their behavior regarding neat epoxy resin. Compressive tests, tensile tests and flexural tests were conducted to study the effect of graphene nanoplatelets on neat epoxy resin. By comparing graphene-based and neat epoxy grout, there is no significant increase of strength due to weak interface in the graphene nanoplatelets/epoxy composites. From this experiment, the tension and flexural strength of graphene-based epoxy grouts is slightly lower than ones of neat epoxy grout. Nevertheless, the addition of graphene has produced more consistent results according to a smaller standard deviation of strength. Furthermore, the graphene has also improved the ductility of the grout, hence reducing its brittle behaviour. This shows that the performance of graphene-based grout is reliably predictable and able to minimize sudden rupture. This is important since repair design of damaged pipeline is of deterministic nature.Keywords: composite, epoxy resin, graphene nanoplatelets, pipeline
Procedia PDF Downloads 4838093 Empirical Analyses of Students’ Self-Concepts and Their Mathematics Achievements
Authors: Adetunji Abiola Olaoye
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The study examined the students’ self-concepts and mathematics achievement viz-a-viz the existing three theoretical models: Humanist self-concept (M1), Contemporary self-concept (M2) and Skills development self-concept (M3). As a qualitative research study, it comprised of one research question, which was transformed into hypothesis viz-a-viz the existing theoretical models. Sample to the study comprised of twelve public secondary schools from which twenty-five mathematics teachers, twelve counselling officers and one thousand students of Upper Basic II were selected based on intact class as school administrations and system did not allow for randomization. Two instruments namely 10 items ‘Achievement test in Mathematics’ (r1=0.81) and 10 items Student’s self-concept questionnaire (r2=0.75) were adapted, validated and used for the study. Data were analysed through descriptive, one way ANOVA, t-test and correlation statistics at 5% level of significance. Finding revealed mean and standard deviation of pre-achievement test scores of (51.322, 16.10), (54.461, 17.85) and (56.451, 18.22) for the Humanist Self-Concept, Contemporary Self-Concept and Skill Development Self-Concept respectively. Apart from that study showed that there was significant different in the academic performance of students along the existing models (F-cal>F-value, df = (2,997); P<0.05). Furthermore, study revealed students’ achievement in mathematics and self-concept questionnaire with the mean and standard deviation of (57.4, 11.35) and (81.6, 16.49) respectively. Result confirmed an affirmative relationship with the Contemporary Self-Concept model that expressed an individual subject and specific self-concept as the primary determinants of higher academic achievement in the subject as there is a statistical correlation between students’ self-concept and mathematics achievement viz-a-viz the existing three theoretical models of Contemporary (M2) with -Z_cal<-Z_val, df=998: P<0.05*. The implication of the study was discussed with recommendations and suggestion for further studies proffered.Keywords: contemporary, humanists, self-concepts, skill development
Procedia PDF Downloads 2408092 The Quality Assurance on the Standard of Private Schools in Bangkok
Authors: Autjira Songjan, Poramatdha Chutimant
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This research is intended to study the operational quality assurance of private schools in Bangkok according to the opinions of administrators and teachers. Second is comparing the opinions of administrators and teachers about operating quality assurance process by gender, job and work experience. The sample include administrators and teachers of private schools in the Education School in Bangkok by using a proportion random technic. The questionnaire are used as query operations quality assurance to collect the data of private schools, the statistics that are used to analyze the data using the percentage, mean, standard deviation and Test the difference value and test of variance. The research found that the administrators and teachers have different sex, positions and duties have the different opinions about quality assurance in different statistically insignificant level 0.05 in the elements of performance management and the quality of the service that provided to students in the school.Keywords: educational quality assurance, performance management, private schools in Bangkok, quality of the service
Procedia PDF Downloads 2328091 Behavior of Helical Piles as Foundation of Photovoltaic Panels in Tropical Soils
Authors: Andrea J. Alarcón, Maxime Daulat, Raydel Lorenzo, Renato P. Da Cunha, Pierre Breul
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Brazil has increased the use of renewable energy during the last years. Due to its sunshine and large surface area, photovoltaic panels founded in helical piles have been used to produce solar energy. Since Brazilian territory is mainly cover by highly porous structured tropical soils, when the helical piles are installed this structure is broken and its soil properties are modified. Considering the special characteristics of these soils, helical foundations behavior must be extensively studied. The first objective of this work is to determine the most suitable method to estimate the tensile capacity of helical piles in tropical soils. The second objective is to simulate the behavior of these piles in tropical soil. To obtain the rupture to assess load-displacement curves and the ultimate load, also a numerical modelling using Plaxis software was conducted. Lastly, the ultimate load and the load-displacements curves are compared with experimental values to validate the implemented model.Keywords: finite element, helical piles, modelling, tropical soil, uplift capacity
Procedia PDF Downloads 1748090 A Study of Behaviors in Using Social Networks of Corporate Personnel of Suan Sunandha Rajabhat University
Authors: Wipada Chaiwchan
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This research aims to study behaviors in using social networks of Corporate personnel of Suan Sunandha Rajabhat University. The sample used in the study were two groups: 1) Academic Officer 70 persons and 2) Operation Officer 143 persons were used in this study. The tools in this research consisted of questionnaire which the data were analyzed by using percentage, average (X) and Standard deviation (S.D.) and Independent Sample T-Test to test the difference between the mean values obtained from two independent samples, and One-way anova to analysis of variance, and Multiple comparisons to test that the average pair of different methods by Fisher’s Least Significant Different (LSD). The study result found that the most of corporate personnel have purpose in using social network to information awareness aspect was knowledge and online conference with social media. By using the average more than 3 hours per day in everyday. Using time in working in one day and there are computers connected to the Internet at home, by using the communication in the operational processes. Behaviors using social networks in relation to gender, age, job title, department, and type of personnel. Hypothesis testing, and analysis of variance for the effects of this analysis is divided into three aspects: The use of online social networks, the attitude of the users and the security analysis has found that Corporate Personnel of Suan Sunandha Rajabhat University. Overall and specifically at the high level, and considering each item found all at a high level. By sorting of the social network (X=3.22), The attitude of the users (X= 3.06) and the security (X= 3.11). The overall behaviors using of each side (X=3.11).Keywords: social network, behaviors, social media, computer information systems
Procedia PDF Downloads 3968089 Development of the Independent Building Permit System to Improve Productivity and Quality Service
Authors: Hartomo Soewardi, Bachtiar Jouhari
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Ineffectiveness and inefficiency of the building permit process in Indonesia still becomes a major problems for people to apply. Long time of service, the complicated administration process, and an expensive fees are a process that causing a dissatisfaction and discomfort for applicant. Therefore, it is critical to improve the quality of service of building permit system. Objectives of this research is to develop a better process of the system to improve productivity and quality service. Lean six sigma concept by using DMAIC procedures was used to analyze the existing system. Moreover, improvement of the system was conducted by using the Axiomatic Design method. Verification test was done to test the hypothesis of the proposed system design. Result of this research shows that proposed system can produce increasing 61.8% of efficiency on service time, and more effective and easier.Keywords: axiomatic design, bbuilding permit system, DMAIC, Lean Six Sigma
Procedia PDF Downloads 3308088 Modeling and Statistical Analysis of a Soap Production Mix in Bejoy Manufacturing Industry, Anambra State, Nigeria
Authors: Okolie Chukwulozie Paul, Iwenofu Chinwe Onyedika, Sinebe Jude Ebieladoh, M. C. Nwosu
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The research work is based on the statistical analysis of the processing data. The essence is to analyze the data statistically and to generate a design model for the production mix of soap manufacturing products in Bejoy manufacturing company Nkpologwu, Aguata Local Government Area, Anambra state, Nigeria. The statistical analysis shows the statistical analysis and the correlation of the data. T test, Partial correlation and bi-variate correlation were used to understand what the data portrays. The design model developed was used to model the data production yield and the correlation of the variables show that the R2 is 98.7%. However, the results confirm that the data is fit for further analysis and modeling. This was proved by the correlation and the R-squared.Keywords: General Linear Model, correlation, variables, pearson, significance, T-test, soap, production mix and statistic
Procedia PDF Downloads 4468087 Investigating the Dose Effect of Electroacupuncture on Mice Inflammatory Pain Model
Authors: Wan-Ting Shen, Ching-Liang Hsieh, Yi-Wen Lin
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Electroacupuncture (EA) has been reported effective for many kinds of pain and is a common treatment for acute or chronic pain. However, to date, there are limited studies examining the effect of acupuncture dosage. In our experiment, after injecting mice with Complete Freund’s Adjuvant (CFA) to induce inflammatory pain, two groups of mice were administered two different 15 min EA treatments at 2Hz. The first group received EA at a single acupuncture point (ST36, Zusanli) in both legs (two points), whereas the second group received two acupuncture points in both legs (four points) and the analgesic effect was compared. It was found that double points (ST36, Zusanli and SP6, Sanyinjiao) were significantly superior to single points (ST36, Zusanli) when evaluated using the electronic von Frey Test (mechanic) and Hargreaves’ Test (thermal). Through this study, it is expected more novel physiological mechanisms of acupuncture analgesia will be discovered.Keywords: anti-inflammation, dose effect, electroacupuncture, pain control
Procedia PDF Downloads 1758086 Synthesis and Characterization of Nanocellulose Based Bio-Composites
Authors: Krishnakant Bhole, Neerakallu D. Shivakumar, Shakti Singh Chauhan, Sanketh Tonannavar, Rajath S
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Synthesis of natural-based composite materials is state of the art. This work discusses the preparation and characterization of cellulose nanofibers (CNF) extracted from the bamboo pulp using TEMPO-oxidization and high-pressure homogenization methods. Bio-composites are prepared using synthesized CNF and bamboo particles. Nanocellulose prepared is characterized using SEM and XRD for morphological and crystallinity analysis, and the formation of fibers at the nano level is ensured. Composite specimens are fabricated using these natural sources and subjected to tensile and flexural tests to characterize the mechanical properties such as modulus of elasticity (MOE), modulus of rupture (MOR), and interfacial strength. Further, synthesized nanocellulose is used as a binding agent to prepare particleboards using various natural sources like bamboo, areca nut, and banana in the form of fibers. From the results, it can be inferred that nanocellulose prepared from bamboo pulp acts as a binding agent for making bio-composites. Hence, the concept of using matrix and reinforcement derived from natural sources can be used to prepare green composites that are highly degradable.Keywords: nanocellulose, biocomposite, CNF, bamboo
Procedia PDF Downloads 888085 English Test Success among Syrian Refugee Girls Attending Language Courses in Lebanon
Authors: Nina Leila Mussa
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Background: The devastating effects of the war on Syria’s educational infrastructure has been widely reported, with millions of children denied access. However, among those who resettled in Lebanon, the impact of receiving educational assistance on their abilities to pass the English entrance exam is not well described. The aim of this study was to identify predictors of success among Syrian refugees receiving English language courses in a Lebanese university. Methods: The database of Syrian refugee girls matriculated in English courses at the American University of Beirut (AUB) was reviewed. The study period was 7/2018-09/2020. Variables compared included: family size and income, welfare status, parents’ education, English proficiency, access to the internet, and need for external help with homework. Results: For the study period, there were 28 girls enrolled. The average family size was 6 (range 4-9), with eight having completed primary, 14 secondary education, and 6 graduated high school. Eighteen were single-income families. After 12 weeks of English courses, 16 passed the Test of English as Foreign Language (TOEFL) from the first attempt, and 12 failed. Out of the 12, 8 received external help, and 6 passed on the second attempt, which brings the total number of successful passing to 22. Conclusion: Despite the tragedy of war, girls receiving assistance in learning English in Lebanon are able to pass the basic language test. Investment in enhancing those educational experiences will be determinantal in achieving widespread progress among those at-risk children.Keywords: refugee girls, TOEFL, education, success
Procedia PDF Downloads 1258084 Perception of Women towards Participation in Employment: A Study on Mumbai Slums Women
Authors: Mukesh Ranjan, Varsha Nagargoje
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Applying the exploratory factor analysis (EFA), Women Employment Participation Perception Index (WEPPI) has been made through 13 components. The basic purpose of the WEPPI is to develop an index or search for the latent factors which will capture the attitude or perception of the Mumbai’s slum women towards women’s employment participation in the job market through primary survey based on 160 observations. Majority of the response analyzed under various socio-economic and demographic characteristics falls in the strongly agree or agree category. It means whether it is age wise, marital status-wise, caste, religion or economic dimension-wise women responded that they should participate in employment in Mumbai. Value of KMO test was 0.544 and chronbac’s alpha value was between 0.5-0.6, so the index falls in poor category and can be improved upon by adding more number of items.Keywords: WEPPI, exploratory factor analysis, KMO test, Chronbac alpha
Procedia PDF Downloads 4848083 Monitoring Three-Dimensional Models of Tree and Forest by Using Digital Close-Range Photogrammetry
Authors: S. Y. Cicekli
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In this study, tree-dimensional model of tree was created by using terrestrial close range photogrammetry. For this close range photos were taken. Photomodeler Pro 5 software was used for camera calibration and create three-dimensional model of trees. In first test, three-dimensional model of a tree was created, in the second test three-dimensional model of three trees were created. This study aim is creating three-dimensional model of trees and indicate the use of close-range photogrammetry in forestry. At the end of the study, three-dimensional model of tree and three trees were created. This study showed that usability of close-range photogrammetry for monitoring tree and forests three-dimensional model.Keywords: close- range photogrammetry, forest, tree, three-dimensional model
Procedia PDF Downloads 3898082 The Positive Effects of Processing Instruction on the Acquisition of French as a Second Language: An Eye-Tracking Study
Authors: Cecile Laval, Harriet Lowe
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Processing Instruction is a psycholinguistic pedagogical approach drawing insights from the Input Processing Model which establishes the initial innate strategies used by second language learners to connect form and meaning of linguistic features. With the ever-growing use of technology in Second Language Acquisition research, the present study uses eye-tracking to measure the effectiveness of Processing Instruction in the acquisition of French and its effects on learner’s cognitive strategies. The experiment was designed using a TOBII Pro-TX300 eye-tracker to measure participants’ default strategies when processing French linguistic input and any cognitive changes after receiving Processing Instruction treatment. Participants were drawn from lower intermediate adult learners of French at the University of Greenwich and randomly assigned to two groups. The study used a pre-test/post-test methodology. The pre-tests (one per linguistic item) were administered via the eye-tracker to both groups one week prior to instructional treatment. One group received full Processing Instruction treatment (explicit information on the grammatical item and on the processing strategies, and structured input activities) on the primary target linguistic feature (French past tense imperfective aspect). The second group received Processing Instruction treatment except the explicit information on the processing strategies. Three immediate post-tests on the three grammatical structures under investigation (French past tense imperfective aspect, French Subjunctive used for the expression of doubt, and the French causative construction with Faire) were administered with the eye-tracker. The eye-tracking data showed the positive change in learners’ processing of the French target features after instruction with improvement in the interpretation of the three linguistic features under investigation. 100% of participants in both groups made a statistically significant improvement (p=0.001) in the interpretation of the primary target feature (French past tense imperfective aspect) after treatment. 62.5% of participants made an improvement in the secondary target item (French Subjunctive used for the expression of doubt) and 37.5% of participants made an improvement in the cumulative target feature (French causative construction with Faire). Statistically there was no significant difference between the pre-test and post-test scores in the cumulative target feature; however, the variance approximately tripled between the pre-test and the post-test (3.9 pre-test and 9.6 post-test). This suggests that the treatment does not affect participants homogenously and implies a role for individual differences in the transfer-of-training effect of Processing Instruction. The use of eye-tracking provides an opportunity for the study of unconscious processing decisions made during moment-by-moment comprehension. The visual data from the eye-tracking demonstrates changes in participants’ processing strategies. Gaze plots from pre- and post-tests display participants fixation points changing from focusing on content words to focusing on the verb ending. This change in processing strategies can be clearly seen in the interpretation of sentences in both primary and secondary target features. This paper will present the research methodology, design and results of the experimental study using eye-tracking to investigate the primary effects and transfer-of-training effects of Processing Instruction. It will then provide evidence of the cognitive benefits of Processing Instruction in Second Language Acquisition and offer suggestion in second language teaching of grammar.Keywords: eye-tracking, language teaching, processing instruction, second language acquisition
Procedia PDF Downloads 2818081 Topology Optimization Design of Transmission Structure in Flapping-Wing Micro Aerial Vehicle via 3D Printing
Authors: Zuyong Chen, Jianghao Wu, Yanlai Zhang
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Flapping-wing micro aerial vehicle (FMAV) is a new type of aircraft by mimicking the flying behavior to that of small birds or insects. Comparing to the traditional fixed wing or rotor-type aircraft, FMAV only needs to control the motion of flapping wings, by changing the size and direction of lift to control the flight attitude. Therefore, its transmission system should be designed very compact. Lightweight design can effectively extend its endurance time, while engineering experience alone is difficult to simultaneously meet the requirements of FMAV for structural strength and quality. Current researches still lack the guidance of considering nonlinear factors of 3D printing material when carrying out topology optimization, especially for the tiny FMAV transmission system. The coupling of non-linear material properties and non-linear contact behaviors of FMAV transmission system is a great challenge to the reliability of the topology optimization result. In this paper, topology optimization design based on FEA solver package Altair Optistruct for the transmission system of FMAV manufactured by 3D Printing was carried out. Firstly, the isotropic constitutive behavior of the Ultraviolet (UV) Cureable Resin used to fabricate the structure of FMAV was evaluated and confirmed through tensile test. Secondly, a numerical computation model describing the mechanical behavior of FMAV transmission structure was established and verified by experiments. Then topology optimization modeling method considering non-linear factors were presented, and optimization results were verified by dynamic simulation and experiments. Finally, detail discussions of different load status and constraints were carried out to explore the leading factors affecting the optimization results. The contributions drawn from this article helpful for guiding the lightweight design of FMAV are summarizing as follow; first, a dynamic simulation modeling method used to obtain the load status is presented. Second, verification method of optimized results considering non-linear factors is introduced. Third, based on or can achieve a better weight reduction effect and improve the computational efficiency rather than taking multi-states into account. Fourth, basing on makes for improving the ability to resist bending deformation. Fifth, constraint of displacement helps to improve the structural stiffness of optimized result. Results and engineering guidance in this paper may shed lights on the structural optimization and light-weight design for future advanced FMAV.Keywords: flapping-wing micro aerial vehicle, 3d printing, topology optimization, finite element analysis, experiment
Procedia PDF Downloads 1718080 Test of Biological Control against Brachytrupes Megacephalus Lefèbre, 1827 (Orthoptera, Gryllinae) by Using Entomopathogenic Fungi
Authors: W. Lakhdari, B. Doumendji-Mitich, A. Dahliz, S. Doumendji, Y. Bouchikh, R. M'lik, H. Hammi, A. Soud
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This work was done in order to fight against Brachytrupes megacephalus, a major pest in the Algerian oasis and promote one aspect of biological control against it. He wears a hand on the isolation and identification of indigenous fungi on imagos of this insect harvested in the station of INRAA Touggourt and secondly, the study of the pathogenicity of these strains fungal on this orthoptère adults. The results obtained showed the presence of six different species of entomopathogenic fungi, it is: Aspergillus flavus, Fusarium sp, Beauveria bassiana, Penicillium sp, Metharizium anisopliae and Aspergillus Niger. The pathogenicity test using fungi Beauveria bassiana strains and Metharizium anisopliae. On adult of B. megacephalus highlights the effectiveness of these strains of predatory adults, with a mortality rate approaching 100% after 11 days.Keywords: biological control, brachytrupes megacephalus, entomopathogenic fungi, Southeastern Algeria
Procedia PDF Downloads 4118079 Enhancing Water Purification with Angiosperm Xylem Filters
Authors: Yinan Zhou
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One in four people in the world still lack access to clean drinking water, and there is a current lack of cost-effective ways for water-scarce regions to access it. This study seeks to investigate the solutions to water filtration in rural China as well as test the feasibility of using angiosperms as xylem candidates. Four angiosperms that are found in China and around Asia were subject to three tests to test their filtration capacity: ink water filtration, creek water filtration, and microparticle filtration. Analysis of the experiments demonstrated that Celtis Sinensis was able to produce one of the clearest solutions, filter out large debris and bacteria, and reject microparticles almost completely. Celtis Sinensis proves that angiosperm xylem filters are also competent filter candidates and, due to their availability in China, can be used as a nearby source of water filtration. Further research should be done on scaling production to a larger scale and also on the filtration of viruses.Keywords: xylem filter, water quality, China, angiosperms, bacteria
Procedia PDF Downloads 128078 The Effects of a Nursing Dignity Care Program on Patients’ Dignity in Care
Authors: Yea-Pyng Lin
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Dignity is a core element of nursing care. Maintaining the dignity of patients is an important issue because the health and recovery of patients can be adversely affected by a lack of dignity in their care. The aim of this study was to explore the effects of a nursing dignity care program upon patients’ dignity in care. A quasi-experimental research design was implemented. Nurses were recruited by purposive sampling, and their patients were recruited by simple random sampling. Nurses in the experimental group received the nursing educational program on dignity care, while nurses in the control group received in-service education as usual. Data were collected via two instruments: the dignity in care scale for nurses and the dignity in care scale to patients, both of which were developed by the researcher. Both questionnaires consisted of three domains: agreement, importance, and frequencies of providing dignity care. A total of 178 nurses in the experimental group and 193 nurses in the control group completed the pretest and the follow-up evaluations at the first month, the third month, and the sixth month. The number of patients who were cared for by the nurses in the experimental group was 94 in the pretest. The number of patients in the post-test at the first, third, and sixth months were 91, 85, and 77, respectively. In the control group, 88 patients completed the II pretest, and 80 filled out the post-test at the first month, 77 at the third, and 74 at the sixth month. The major findings revealed the scores of agreement domain among nurses in the experimental group were found significantly different from those who in the control group at each point of time. The scores of importance domain between these two groups also displayed significant differences at pretest and the first month of post-test. Moreover, the frequencies of proving dignity care to patients were significant at pretest, the third month and sixth month of post-test. However, the experimental group had only significantly different from those who in the control group on the frequencies of receiving dignity care especially in the items of ‘privacy care,’ ‘communication care,’ and ‘emotional care’ for the patients. The results show that the nursing program on dignity care could increase nurses’ dignity care for patients in three domains of agreement, importance, and frequencies of providing dignity care. For patients, only the frequencies of receiving dignity care were significantly increased. Therefore, the nursing program on dignity care could be applicable for nurses’ in-service education and practice to enhance the ability of nurses to care for patient’s dignity.Keywords: nurses, patients, dignity care, quasi-experimental, nursing education
Procedia PDF Downloads 4678077 Enabling Oral Communication and Accelerating Recovery: The Creation of a Novel Low-Cost Electroencephalography-Based Brain-Computer Interface for the Differently Abled
Authors: Rishabh Ambavanekar
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Expressive Aphasia (EA) is an oral disability, common among stroke victims, in which the Broca’s area of the brain is damaged, interfering with verbal communication abilities. EA currently has no technological solutions and its only current viable solutions are inefficient or only available to the affluent. This prompts the need for an affordable, innovative solution to facilitate recovery and assist in speech generation. This project proposes a novel concept: using a wearable low-cost electroencephalography (EEG) device-based brain-computer interface (BCI) to translate a user’s inner dialogue into words. A low-cost EEG device was developed and found to be 10 to 100 times less expensive than any current EEG device on the market. As part of the BCI, a machine learning (ML) model was developed and trained using the EEG data. Two stages of testing were conducted to analyze the effectiveness of the device: a proof-of-concept and a final solution test. The proof-of-concept test demonstrated an average accuracy of above 90% and the final solution test demonstrated an average accuracy of above 75%. These two successful tests were used as a basis to demonstrate the viability of BCI research in developing lower-cost verbal communication devices. Additionally, the device proved to not only enable users to verbally communicate but has the potential to also assist in accelerated recovery from the disorder.Keywords: neurotechnology, brain-computer interface, neuroscience, human-machine interface, BCI, HMI, aphasia, verbal disability, stroke, low-cost, machine learning, ML, image recognition, EEG, signal analysis
Procedia PDF Downloads 1208076 Analysis of Shallow Foundation Using Conventional and Finite Element Approach
Authors: Sultan Al Shafian, Mozaher Ul Kabir, Khondoker Istiak Ahmad, Masnun Abrar, Mahfuza Khanum, Hossain M. Shahin
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For structural evaluation of shallow foundation, the modulus of subgrade reaction is one of the most widely used and accepted parameter for its ease of calculations. To determine this parameter, one of the most common field method is Plate Load test method. In this field test method, the subgrade modulus is considered for a specific location and according to its application, it is assumed that the displacement occurred in one place does not affect other adjacent locations. For this kind of assumptions, the modulus of subgrade reaction sometimes forced the engineers to overdesign the underground structure, which eventually results in increasing the cost of the construction and sometimes failure of the structure. In the present study, the settlement of a shallow foundation has been analyzed using both conventional and numerical analysis. Around 25 plate load tests were conducted on a sand fill site in Bangladesh to determine the Modulus of Subgrade reaction of ground which is later used to design a shallow foundation considering different depth. After the collection of the field data, the field condition was appropriately simulated in a finite element software. Finally results obtained from both the conventional and numerical approach has been compared. A significant difference has been observed in the case of settlement while comparing the results. A proper correlation has also been proposed at the end of this research work between the two methods of in order to provide the most efficient way to calculate the subgrade modulus of the ground for designing the shallow foundation.Keywords: modulus of subgrade reaction, shallow foundation, finite element analysis, settlement, plate load test
Procedia PDF Downloads 1848075 Mechanical Testing of Composite Materials for Monocoque Design in Formula Student Car
Authors: Erik Vassøy Olsen, Hirpa G. Lemu
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Inspired by the Formula-1 competition, IMechE (Institute of Mechanical Engineers) and Formula SAE (Society of Mechanical Engineers) organize annual competitions for University and College students worldwide to compete with a single-seat race car they have designed and built. The design of the chassis or the frame is a key component of the competition because the weight and stiffness properties are directly related with the performance of the car and the safety of the driver. In addition, a reduced weight of the chassis has a direct influence on the design of other components in the car. Among others, it improves the power to weight ratio and the aerodynamic performance. As the power output of the engine or the battery installed in the car is limited to 80 kW, increasing the power to weight ratio demands reduction of the weight of the chassis, which represents the major part of the weight of the car. In order to reduce the weight of the car, ION Racing team from the University of Stavanger, Norway, opted for a monocoque design. To ensure fulfilment of the above-mentioned requirements of the chassis, the monocoque design should provide sufficient torsional stiffness and absorb the impact energy in case of a possible collision. The study reported in this article is based on the requirements for Formula Student competition. As part of this study, diverse mechanical tests were conducted to determine the mechanical properties and performances of the monocoque design. Upon a comprehensive theoretical study of the mechanical properties of sandwich composite materials and the requirements of monocoque design in the competition rules, diverse tests were conducted including 3-point bending test, perimeter shear test and test for absorbed energy. The test panels were homemade and prepared with an equivalent size of the side impact zone of the monocoque, i.e. 275 mm x 500 mm so that the obtained results from the tests can be representative. Different layups of the test panels with identical core material and the same number of layers of carbon fibre were tested and compared. Influence of the core material thickness was also studied. Furthermore, analytical calculations and numerical analysis were conducted to check compliance to the stated rules for Structural Equivalency with steel grade SAE/AISI 1010. The test results were also compared with calculated results with respect to bending and torsional stiffness, energy absorption, buckling, etc. The obtained results demonstrate that the material composition and strength of the composite material selected for the monocoque design has equivalent structural properties as a welded frame and thus comply with the competition requirements. The developed analytical calculation algorithms and relations will be useful for future monocoque designs with different lay-ups and compositions.Keywords: composite material, Formula student, ION racing, monocoque design, structural equivalence
Procedia PDF Downloads 5048074 Modified Side Plate Design to Suppress Lateral Torsional Buckling of H-Beam for Seismic Application
Authors: Erwin, Cheng-Cheng Chen, Charles J. Salim
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One of the method to solve the lateral torsional buckling (LTB) problem is by using side plates to increased the buckling resistance of the beam. Some modifications in designing the side plates are made in this study to simplify the construction in the field and reduce the cost. At certain region, side plates are not added: (1) At the beam end to preserve some spaces for bolt installation, but the beam is strengthened by adding cover plate at both flanges and (2) at the middle span of the beam where the moment is smaller. Three small scale full span beam specimens are tested under cyclic loading to investigate the LTB resistant and the ductility of the proposed design method. Test results show that the LTB deformation can be effectively suppressed and very high ductility level can be achieved. Following the test, a finite element analysis (FEA) model is established and is verified using the test results. An intensive parametric study is conducted using the established FEA model. The analysis reveals that the length of side plates is the most important parameter determining the performance of the beam and the required side plates length is determined by some parameters which are (1) beam depth to flange width ratio, (2) beam slenderness ratio (3) strength and thickness of the side plates, (4) compactness of beam web and flange, and (5) beam yield strength. At the end of the paper, a design formula to calculate the required side plate length is suggested.Keywords: cover plate, earthquake resistant design, lateral torsional buckling, side plate, steel structure
Procedia PDF Downloads 1768073 An Investigation of Aluminum Foil-Epoxy Laminated Composites for Rapid Tooling Applications
Authors: Kevlin Govender, Anthony Walker, Glen Bright
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Mass customization is an area of increased importance and the development of rapid tooling applications is pivotal to the success of mass customization. This paper presents a laminated object manufacturing (LOM) process for rapid tooling. The process is termed 3D metal laminate printing and utilizes domestic-grade aluminum foil and epoxy for layered manufacturing. A detailed explanation of the process is presented to produce complex metal laminated composite parts. Aluminum-epoxy composite specimens were manufactured from 0.016mm aluminum and subjected to tensile tests to determine the mechanical properties of the manufactured composite in relation to solid metal specimens. The fracture zone of the specimens was analyzed under scanning electron microscopy (SEM) in order to characterize the fracture mode and study the interfacial bonding of the manufactured laminate specimens.Keywords: 3D metal laminate printer, aluminum-epoxy composite, laminated object manufacturing, rapid tooling
Procedia PDF Downloads 2928072 The Effect of Aerobic Training and Consumption of Apple Vinegar on Cardiovascular Risk Factor in Older Women
Authors: S. Fazelifar, M. Ghasemi
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Aim: Recent studies on cardiovascular risk factors have been focused on the new markers of inflammatory diseases such as C-reactive protein (CRP). Research evidence shows that physical activity along with other factors such as reduced smoking, controlling blood pressure, control blood lipids TC, LDL-c, HDL-c and having a healthy weight can reduce the risk of chronic heart disease (CHD) .Therefore, the aim of this study was to determine the effect of twelve weeks aerobic exercise and consumption of apple vinegar on cardiovascular risk factor in older women. Methodology: 28 inactive women (mean body weight 72.13 ± 8.6 kg, height 157 ± 7.4cm, age 48.06 ± 5.18 years and BMI 28.2 ± 3.2 kg/m2) by recall and notice of investigation, among of the eligible voters recruited and randomly divided in 4 groups: control, apple vinegar, exercise, exercise + apple vinegar. The training program includes a 20-minute warm-up and stretching, running for 15 minutes in the first session with an intensity of 80% of maximum heart rate and an increase in one-minute run time in next training session. Also, subjects in experimental groups received daily specified amount of 50 ml apple vinegar. Blood samples were collected from the brachial vein in before and after training to measure CRP and blood lipids (cholesterol, HDL, VLDL, LDL). The levels of CRP were measured by ELISA way. K-S test to determine the normality of the data and analysis of variance for repeated measures was used to analyze the data. A significant difference in the p < 0/05 accepted. Results: The results indicated that individual characteristics including height, weight, age, and body mass index were not significantly different among the four groups. The results showed that levels of CRP and LDL cholesterol were significantly reduced in all groups at post-test compared to the pre-test. The HDL levels increased significantly in all groups in post-test compared to the pre-test. Analysis of the data indicates that levels of CRP, TC, and LDL were significantly reduced in all groups compared to the control group, while the changes in the other groups were not significant relative to each other. Conclusion: Results of this study showed that twelve weeks of aerobic exercise with apple vinegar cause a significant decrease in CRP, cholesterol, LDL, and significantly increased HDL levels. According to the results of this study, it is possible that aerobic exercise with apple vinegar can inhibit CRP and undesirable fats. Considering the strong association between the inflammatory indices and the prevalence of cardiovascular diseases, every factor that decreases these indices can reduce the cardiovascular complications.Keywords: aerobic exercise, apple vinegar, CRP, older women
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