Search results for: torsional shear test

Authors: Hassan Mohammad Karimi, Ali Salehzade Nobari, Hosein Shahverdi

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With the advancement of technology and the decreasing weight of aerial structures, there is a growing demand for alternative energy sources. Structural vibrations can now be utilized to power low-power sensors for monitoring structural health and charging small batteries in drones. Research on extracting energy from flutter using piezoelectric has been extensive in recent years. This article specifically examines the use of a single-jointed beam with a free surface attached to its free end and a bimorph piezoelectric patch connected to the joint, providing two degrees of torsional and bending freedom. The study investigates the voltage harvested at various wind speeds and bending and twisting stiffness in a wind tunnel. The results indicate that as flutter speed increases, the output voltage also increases to some extent. However, at high wind speeds, the limited cycle created becomes unstable, negatively impacting the harvester's performance. These findings align with other research published in reputable scientific journals.

Keywords: energy harvesting, piezoelectric, flutter, wind tunnel

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Authors: S. A. Naeini, Z. Eftekhari

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Liquefaction phenomenon in sand is nowadays a classical soil mechanics subject. Using a cyclic triaxial test apparatus, we use non-woven geotextile reinforcement to improve the liquefaction resistance of sand. The layer configurations used are zero, one, two and three horizontal reinforcing layers in a triaxial test sample. The influences of the number of geotextile layers, and cyclic stress ratio (CSR) were studied and described. The results illustrated that the geotextile inclusion increases liquefaction resistance.

Keywords: liquefaction resistance, geotextile, sand, cyclic triaxial test, cyclic stress ratio

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Authors: Atitallah Sofien, Missaoui Nada, Ben Rabeh Rania, Yahyaoui Salem, Mazigh Sonia, Bouyahia Olfa, Boukthir Samir

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Introduction: Acute bronchiolitis (AB) is a real public health problem on a global and national scale. Its treatment is most often outpatient. The use of audio-visual supports, such as educational videos, is an innovation in therapeutic education in outpatient treatment. The aim of our study was to evaluate the impact of an educational video on the knowledge, attitudes, and practices of mothers of infants with AB. Methodology: This was a descriptive, analytical, and cross-sectional study with prospective data collection, including mothers of infants with AB. We assessed mothers' knowledge, attitudes, and practices regarding AB, and we created an educational video. We used a questionnaire written in Tunisian Arabic concerning sociodemographic data, mothers' knowledge and attitudes regarding AB, and their opinions on the video, as well as an observation grid to evaluate their practices on the nasopharyngeal unblocking technique. We compared the different parameters before and after watching the video. Results: We noted a statistically significant improvement in mothers' knowledge scores on AB (7.46 in the pre-test versus 14.08 in the post-test; p≤0.05), practices (12.42 in the pre-test versus 18 in the post-test; p≤0.05) and attitudes (5.86 in pre-test versus 9.02 in post-test; p≤0.05). Conclusion: The use of an educational video has a positive impact on the knowledge, practices, and attitudes of mothers towards AB.

Keywords: acute bronchiolitis, therapeutic education, mothers, educational video

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Authors: Khawla Saad Albalawi

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The aim of this research was to explore the effectiveness of the internet counseling in reducing social shyness among the university's students. The sample consisted of 40 students and was divided into two groups: an experimental group and a control group. The social shyness scale (SSS) was administered to both groups before applying the counseling to the experimental group (as a pre-test). After that, the internet counseling was applied to the experimental group. Next, the SSS was administered to both groups (as a post-test). Finally, the SSS was administered to the experimental group (as an iterative application). Results suggest that: 1. There is a significant difference between the two groups in the post-test in all dimensions and the total score of the (SSS) in favor of the experimental group in all cases. 2. There is a significant difference between the pre- and the post-test of the experimental group in all dimensions and the total score of the (SSS) in favor of the post-test in all cases. 3. There is no significant difference between the post-test and the iterative application of the experimental group in all dimensions and the total score of the (SSS). The above results were discussed in light of previous research. Recommendations and future researches were suggested.

Keywords: internet psychological clinics, social interaction disorders, shyness, Twitter, Facebook

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Authors: Charizza D. Montarin, Daryl Jae S. Sigue, Gilford Estores

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Philippines was moderately vulnerable to corrosion and to prevent this problem, surface coating should be applied. The main objective of this research was to develop and optimize a bio-based mixture of Pili Resin and Lime as Coating Materials. There are three (3) factors to be considered in choosing the best coating material such as chemical adhesion, friction, and the bearing/shear against the steel bar-concrete interface. Fortunately, both proportions of the Bio-based coating materials (50:50 and 65:35) do not have red rust formation complying with ASTM B117 but failed in terms of ASTM D 3359. Splitting failures of concrete were observed in the Unconfined Reinforced Concrete Samples. All of the steel bars (uncoated and coated) surpassed the Minimum Bond strength (NSCP 2015) about 203% to 285%. The experiments were about 1% to 3% of the results from the ANSYS Simulations with and without Salt Spray Test. Using the bio-based and epoxy coatings, normal splitting strengths were declined. However, there has no significant difference between the results. Thus, the bio-based coating materials can be used as an alternative for the epoxy coating materials and it was highly recommended for Low – Rise Building only.

Keywords: Canarium luzonicum, calcium oxide, corrosion, finite element simulations

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Authors: Jui-Teng Liao

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The selected-response (SR) format has been commonly adopted to assess academic reading in both formal and informal testing (i.e., standardized assessment and classroom assessment) because of its strengths in content validity, construct validity, as well as scoring objectivity and efficiency. When developing a second language (L2) reading test, researchers indicate that the longer the test (e.g., more test items) is, the higher reliability and validity the test is likely to produce. However, previous studies have not provided specific guidelines regarding the optimal length of a test or the most suitable number of test items or reading passages. Additionally, reading tests often include different question types (e.g., factual, vocabulary, inferential) that require varying degrees of reading comprehension and cognitive processes. Therefore, it is important to investigate the impact of question types on the number of items in relation to the score reliability of L2 reading tests. Given the popularity of the SR question format and its impact on assessment results on teaching and learning, it is necessary to investigate the degree to which such a question format can reliably measure learners’ L2 reading comprehension. The present study, therefore, adopted the generalizability (G) theory to investigate the score reliability of the SR format in L2 reading tests focusing on how many test items a reading test should include. Specifically, this study aimed to investigate the interaction between question types and the number of items, providing insights into the appropriate item count for different types of questions. G theory is a comprehensive statistical framework used for estimating the score reliability of tests and validating their results. Data were collected from 108 English as a second language student who completed an English reading test comprising factual, vocabulary, and inferential questions in the SR format. The computer program mGENOVA was utilized to analyze the data using multivariate designs (i.e., scenarios). Based on the results of G theory analyses, the findings indicated that the number of test items had a critical impact on the score reliability of an L2 reading test. Furthermore, the findings revealed that different types of reading questions required varying numbers of test items for reliable assessment of learners’ L2 reading proficiency. Further implications for teaching practice and classroom-based assessments are discussed.

Keywords: second language reading assessment, validity and reliability, Generalizability theory, Academic reading, Question format

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Authors: Kartika Marta Budiana

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Low competence in speaking for the students of Non English native speakers have been crucial so far for the teachers in language teaching in Indonesia. This study attempts to explore the effect of video using in teaching speaking onstudents of non-native English speakers at STIE Perbanas Surabaya. This includes investigate the students` attitudes toward the video used in classroom. This is a quantitative research that is an experimental one based on analyses derived the concepts of from teaching speaking and the use of video. There are two classes observed, the experimental and the control one. The experimental consist of 28 students and the control class consists of 25 students. Before the treatment given, both of the group is given the pre-test to check their ability level. Then, after the treatment is given, the post-test is given to the both groups. Then, the students were given treatment how to conduct a meeting that they learnt from a video of business English. The post test was held after they undergone a treatment. The instruments to get the data are the oral test and questionnaire. The data of this study is students` score and from the tests` score it can be seen there is a positive significant difference in the experimental group. The t-test to test hypothesize also shows that it is accepted which said that there is an improvement on the students` speaking competence achievement. In conclusion, the video effects on the significant difference on the students speaking competence achievement.

Keywords: video, teaching, speaking, Indonesia

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Authors: Thanawat Chuleekiat

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Socketing of bored piles in rock is always seen as a matter of debate on construction sites between consultants and contractors. The socketing depth normally depends on the type of rock, depth at which the rock is available below the pile cap and load carrying capacity of the pile. In this paper, the review of field load test data of drilled shaft socketed in weathered limestone conducted using conventional static pile load test and dynamic pile load test was made to evaluate a unit shaft friction for the bored piles socketed in weathered limestone (weak rock). The borehole drilling data were also reviewed in conjunction with the pile test result. In addition, the back-calculated unit shaft friction was reviewed against various empirical methods for bored piles socketed in weak rock. The paper concludes with an estimated ultimate unit shaft friction from the case study in Qatar for preliminary design.

Keywords: piled foundation, weathered limestone, shaft friction, rock socket, pile load test

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Authors: Abdu Zakari, Sai’d Jibril, Adoum A. Omar

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The leaves of Combretum molle was selected on the basis of its uses in folk medicine as insecticides. The leave extracts of Combretum molle was tested against the larvae of Artemia salina, i.e. Brine Shrimp Lethality Test (BST), Culex quinquefasciatus Say (Filaria disease vector) i.e. Larvicidal Test, using crude ethanol, n-hexane, chloroform, ethyl acetate, and methanol extracts. The methanolic extract proved to be the most effective in inducing complete lethality at minimum doses both in the BST and the Larvicidal activity test. The LC50¬ values obtained are 24.85 µg/ml and 0.4µg/ml respectively. The bioactivity-guided column chromatography afforded the pure compound ACM–3. ACM-3 was not active in the BST with LC50 value >1000µg/ml, but was active in the Larvicidal activity test with LC50 value 4.0µg/ml. ACM-3 was proposed to have the structure I, (Cholesta-β-D-Glucopyranoside).

Keywords: toxicity, larvicidal, Combretum molle, Artemia salina, Culex quinquefasciatus Say.

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Authors: Seyed Mehdi Seyed Alizadeh, Christoph Arns, Shane Latham

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Geomechanical characterization of rocks in detail and its possible implications on flow properties is an important aspect of reservoir characterization workflow. In order to gain more understanding of the microstructure evolution of reservoir rocks under stress a series of axisymmetric triaxial tests were performed on two different analogue rock samples. In-situ compression tests were coupled with high resolution micro-Computed Tomography to elucidate the changes in the pore/grain network of the rocks under pressurized conditions. Two outcrop sandstones were chosen in the current study representing a various cementation status of well-consolidated and weakly-consolidated granular system respectively. High resolution images were acquired while the rocks deformed in a purpose-built compression cell. A detailed analysis of the 3D images in each series of step-wise compression tests (up to the failure point) was conducted which includes the registration of the deformed specimen images with the reference pristine dry rock image. Digital Image Correlation (DIC) technique based on the intensity of the registered 3D subsets and particle tracking are utilized to map the displacement fields in each sample. The results suggest the complex architecture of the localized shear zone in well-cemented Bentheimer sandstone whereas for the weakly-consolidated Castlegate sandstone no discernible shear band could be observed even after macroscopic failure. Post-mortem imaging a sister plug from the friable rock upon undergoing continuous compression reveals signs of a shear band pattern. This suggests that for friable sandstones at small scales loading mode may affect the pattern of deformation. Prior to mechanical failure, the continuum digital image correlation approach can reasonably capture the kinematics of deformation. As failure occurs, however, discrete image correlation (i.e. particle tracking) reveals superiority in both tracking the grains as well as quantifying their kinematics (in terms of translations/rotations) with respect to any stage of compaction. An attempt was made to quantify the displacement field in compression using continuum Digital Image Correlation which is based on the reference and secondary image intensity correlation. Such approach has only been previously applied to unconsolidated granular systems under pressure. We are applying this technique to sandstones with various degrees of consolidation. Such element of novelty will set the results of this study apart from previous attempts to characterize the deformation pattern in consolidated sands.

Keywords: deformation mechanism, displacement field, shear behavior, triaxial compression, X-ray micro-CT

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Authors: Barry D. Kyle, Jessica Boyd, Robin Pickersgill, Nicole Squires, Cynthia Balion

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Background-Aim: Fentanyl is a highly-potent synthetic μ-opioid receptor agonist used for exceptional pain management. Its main metabolite, norfentanyl, is typically present in urine at significantly high concentrations (i.e. ~20%) representing an effective targeting molecule for immunoassay detection. Here, we evaluated the NCS^TM One Step Fentanyl Test Device© and the BTNX Rapid Response^TM Single Drug Test Strip© point of care (POC) test strips targeting norfentanyl (20 ng/ml) and fentanyl (100 ng/ml) molecules for potential risperidone interference. Methods: POC tests calibrated against norfentanyl (20 ng/ml) used [immunochromatographic] lateral flow devices to provide qualitative results within five minutes of urine sample contact. Results were recorded as negative if lines appeared in the test and control regions according to manufacturer’s instructions. Positive results were recorded if no line appeared in the test region (i.e., control line only visible). Pooled patient urine (n=20), that screened negative for drugs of abuse (using NCS One Step Multi-Line Screen) and fentanyl (using BTNX Rapid Response Strip) was used for spiking studies. Urine was spiked with risperidone alone and with combinations of fentanyl, norfentanyl and/or risperidone to evaluate cross-reactivity in each test device. Results: A positive screen result was obtained when 8,000 ng/mL of risperidone was spiked into drug free urine using the NCS test device. Positive screen results were also obtained in spiked urine samples containing fentanyl and norfentanyl combinations below the cut-off concentrations when 4000 ng/mL risperidone was present using the NCS testing device. There were no screen positive test results using the BTNX test strip with up to 8,000 ng/mL alone or in combination with concentrations of fentanyl and norfentanyl below the cut-off. Both devices screened positive when either fentanyl or norfentanyl exceeded the cut-off threshold in the absence and presence of risperidone. Conclusion: We report that urine samples containing risperidone may give a false positive result using the NCS One Step Fentanyl Test Device.

Keywords: fentanyl, interferences, point of care test, Risperidone

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Authors: Rakesh C. Mathad, G. Y. Lokesh, Basavegowda

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In agriculture using quality seeds of improved varieties is very important to ensure higher productivity thereby food security and sustainability. To ensure good productivity, seeds should have characters as described by the breeder. To know whether the characters as described by the breeder are expressing in a variety such as genuineness or genetic purity, field grow out test (GOT) is done. In pigeon pea which is long durational crop, conducting a GOT may take very long time and expensive also. Since in pigeon pea flower character is a most distinguishing character from the contaminants, conducting a field grow out test require 120-130 days or till flower emergence, which may increase cost of storage and seed production. This will also delay the distribution of seed inventory to the pigeon pea growing areas. In this view during 2014-15 with financial support of Govt. of Karnataka, India, a project to develop a molecular genetic test for newly developed variety of pigeon pea cv.TS3R was commissioned at Seed Unit, UAS, Raichur. A molecular test was developed with the help SSR markers to identify pure variety from possible off types in newly released pigeon pea variety TS3R. In the investigation, 44 primer pairs were screened to identify the specific marker associated with this variety. Pigeon pea cv. TS3R could be clearly identified by using the primer CCM 293 based on the banding pattern resolved on gel electrophoresis and PCR reactions. However some of the markers like AHSSR 46, CCM 82 and CCM 57 can be used to test other popular varieties in the region like Asha, GRG-811 and Maruti respectively. Further to develop this in to a lab test, the seed sample size was standardized to 200 seeds and a grow out matrix was developed. This matrix was used to sample 12 days old leaves to extract DNA. The lab test results were validated with actual field GOT test results and found variations within the acceptable limit of 1%. This molecular method can now be employed to test the genetic purity in pigeon pea cv TS3R which reduces the time and can be a cheaper alternative method for field GOT.

Keywords: genuineness, grow-out matrix, molecular genetic purity, SSR markers

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Authors: Jaemoon Lim

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To construct the lumped spring-mass model considering the occupants for the offset frontal crash, the SISAME software and the NHTSA test data were used. The data on 56 kph 40% offset frontal vehicle to deformable barrier crash test of a MY2007 Mazda 6 4-door sedan were obtained from NHTSA test database. The overall behaviors of B-pillar and engine of simulation models agreed very well with the test data. The trends of accelerations at the driver and passenger head were similar but big differences in peak values. The differences of peak values caused the large errors of the HIC36 and 3 ms chest g’s. To predict well the behaviors of dummies, the spring-mass model for the offset frontal crash needs to be improved.

Keywords: chest g’s, HIC36, lumped spring-mass model, offset frontal impact, SISAME

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Authors: Svetlana Pushkar

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Eco-indicator 99 (EI99) considers fundamental life cycle assessment (LCA) uncertainties via egalitarian/egalitarian (e/e), hierarchist/hierarchist (h/h), individualist/individualist (i/i), individualist/average (i/a), egalitarian/average (e/a), and hierarchist/average (h/a) methodological options. The objective of this study is to provide a reliable two-stage nested mixed balanced Analysis of Variance (ANOVA) test as a supplemental test to EI99 to address the problematic combination of similarly and not similarly produced materials usually found in building technologies. The robustness of the test was determined from both the “EI99 (all options)” stage (including e/e, i/i, h/h, e/a, i/a, and h/a - all methodological options) and the “EI99 (perspectives)” stage (including e/e, i/i, and h/h methodological options of EI99 - the methodological options with their particular weighting set or e/a, i/a, and h/a methodological options of EI99 - the methodological options with the average weighting set) of evaluating building technologies.

Keywords: building technologies, LCA uncertainty, Eco-indicator 99, two-stage nested mixed ANOVA test

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Authors: Sadeq Al Yaari, Nassr Almaflehi, Ayman Al Yaari, Adham Al Yaari, Montaha Al Yaari, Aayah Al Yaari, Sajedah Al Yaari

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Background: Assessment of language-related functional activities (ALFA) is of vital importance in assessing aphasics’ performance of both sexes. However, the validity and reliability of this language therapeutic test has never been validated in the Arabic medical literature. Purpose: The aim of this study was to validate the test by assessing the language-related functional activities of 100 gender aphasics based in a medical faculty. Design: ALFA Pre-and-posttest was administered twice in three weeks to test the language-related functional activities of 100 gender aphasics. Settings: Al Khars hospital in Al Ahsa’a, Kingdom of Saudi Arabia (KSA). Participants: Sixteen to eight-year-old participants (N = 100 men and women) were enrolled in this experiment. Again, the purpose was to assess their language-related functional activities using ALFA. Procedures: The first step was to translate the English version of ALFA test into the mother tongue of the patients (Arabic). Secondly, the translated text is reviewed and edited by three specialists of Arabic language. Having the test standardized, the third step was to assess language-related functional activities of the participants in natural environment. Assessment took place in three weeks. In the first week, a pre-test was administered to the participants at hand and after two weeks, a post-test was administered to identify whether or not significant differences between the two tests (pre-and-posttest) could be observed. Interventions: Outcomes of the results obtained from the analyses were broadly discussed. Linguistic and statistical comparisons were held to illustrate the findings of this study. Main outcomes and Results: The analysis of the obtained results indicated that the performance of the aphasic participants in the post-test did not differ from that of the pre-test (, respectively). Conclusions & Implications: ALFA was proved to be a valid and reliable test. Moreover, outlined results pointed out the importance of assessing not only gender aphasics’ language, but also their language-related functional activities. Further research is needed to explore how gender aphasics’ verbal and non-verbal performances interact.

Keywords: ALFA, language test, Arab aphasics, validity, reliability, psychoneurolinguistics.

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Authors: Marji Umil, Miane Karyle Urolaza, Ian Winston Dale Uy, John Charle Magne Valdez, Karen Elizabeth Valdez, Ervin Charles Valencia, Cheryleen Tan-Chua

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Objective: Distraction techniques can be successful in reducing the anxiety of children during medical procedures. Dental procedures, in particular, are associated with dental anxiety which has been identified as a significant and common problem in children, however, only limited studies were conducted to address such problem. Thus, this study determined the effectiveness of computer video games on the levels of anxiety of children between 5-12 years old scheduled for tooth extraction. Methods: A pre-test post-test quasi-experimental study was conducted involving 30 randomly-assigned subjects, 15 in the experimental and 15 in the control. Subjects in the experimental group played computer video games for a maximum of 15 minutes, however, no intervention was done on the control. The modified Yale Pre-operative Anxiety Scale (m-YPAS) with a Cronbach’s alpha of 0.9 was used to assess anxiety at two different points: upon arrival in the clinic (pre-test anxiety) and 15 minutes after the first measurement (post-test anxiety). Paired t-test and ANCOVA were used to analyze the gathered data. Results: Results showed that there is a significant difference between the pre-test and post-test anxiety scores of the control group (p=0.0002) which indicates an increased anxiety. A significant difference was also noted between the pre-test and post-test anxiety scores of the experimental group (p=0.0002) which indicates decreased anxiety. Comparatively, the experimental group showed lower anxiety score (p=<0.0001) than the control. Conclusion: The use of computer video games is effective in reducing the pre-operative anxiety among children and can be an alternative non-pharmacological management in giving pre-operative care.

Keywords: play therapy, preoperative anxiety, tooth extraction, video games

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Authors: Mehdi Modabberifar, Milad Roodi, Ehsan Souri

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In recent years, honeycomb fiber reinforced plastic (FRP) sandwich panels have been increasingly used in various industries. Low weight, low price, and high mechanical strength are the benefits of these structures. However, their mechanical properties and behavior have not been fully explored. The objective of this study is to conduct a combined numerical-statistical investigation of honeycomb FRP sandwich beams subject to torsion load. In this paper, the effect of geometric parameters of the sandwich panel on the maximum shear strain in both face and core and angle of torsion in a honeycomb FRP sandwich structures in torsion is investigated. The effect of Parameters including core thickness, face skin thickness, cell shape, cell size, and cell thickness on mechanical behavior of the structure were numerically investigated. Main effects of factors were considered in this paper and regression equations were derived. Taguchi method was employed as experimental design and an optimum parameter combination for the maximum structure stiffness has been obtained. The results showed that cell size and face skin thickness have the most significant impacts on torsion angle, maximum shear strain in face and core.

Keywords: finite element, honeycomb FRP sandwich panel, torsion, civil engineering

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Authors: Abdulmagid A. Khattabi, Ahmed A. Hablus, Osama Ab. M. Shafah

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The goal of this work is to understand how the thermal influence of combustion chamber deposits can be utilized to expand the operating range of HCCI combustion. In order to do this, two main objectives must first be met; tracking deposit formation trends in an HCCI engine and determining the sensitivity of HCCI combustion to CCD. This requires testing that demonstrates the differences in combustion between a clean engine and one with deposits coating the chamber. This will involve a long-term test that tracks the effects of CCD on combustion. The test will start with a clean engine. One baseline HCCI operating point is maintained for the duration of the test during which gradual combustion chamber deposit formation will occur. Combustion parameters, including heat release rates and emissions will be tracked for the duration and compared to the case of a clean engine. This work will begin by detailing the specifics of the test procedure and measurements taken throughout the test. Then a review of the effects of the gradual formation of deposits in the engine will be given.

Keywords: fuels, fuel atomization, pattern factor, alternate fuels combustion, efficiency gas turbine combustion, lean blow out, exhaust and liner wall temperature

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Authors: T. Nakkeran, C. Dhamodharan, Win Myint Soe , Ramasamy Deverajan, M. Ganesh Babu

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This manuscript presents the results of an experimental investigation performed to study the material and mechanical properties of two weld joints fabricated within close proximity. The experiment was designed using welded S355 D Z35 with distances between two parallel adjacent weld toes at 8 mm. These distances were less than the distance that has normally been recommended in standards, codes, and specifications. The main idea of the analysis is to determine any significant effects when welding the joints with the close proximity of 8mm using the SAW welding process of the one joint with high heat put and one joint welded with the FCAW welding process and evaluating the destructing and nondestructive testing between the welded joints. Further, we have evaluated the joints with Mechanical Testing for evaluating by performing Tensile test, bend testing, Macrostructure, Microstructure, Hardness test, and Impact testing. After evaluating the final outcome of the result, no significant changes were observed for welding the close proximity of weld of 8mm distance between the joints as compared to the specification minimum distance between the weldments of any design should be 50mm.

Keywords: S355 carbon steel, weld proximity, SAW process, FCAW process, heat input, bend test, tensile test, hardness test, impact test, macro and microscopic examinations

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Authors: Jixiao Tao, Xiaoqiao He

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The present study deals with the finite element (FE) analysis of thermally-induced bistable plate using various plate elements. The quadrilateral plate elements include the 4-node conforming plate element based on the classical laminate plate theory (CLPT), the 4-node and 9-node Mindlin plate element based on the first-order shear deformation laminated plate theory (FSDT), and a displacement-based 4-node quadrilateral element (RDKQ-NL20). Using the von-Karman’s large deflection theory and the total Lagrangian (TL) approach, the nonlinear FE governing equations for plate under thermal load are derived. Convergence analysis for four elements is first conducted. These elements are then used to predict the stable shapes of thermally-induced bistable plate. Numerical test shows that the plate element based on FSDT, namely the 4-node and 9-node Mindlin, and the RDKQ-NL20 plate element can predict two stable cylindrical shapes while the 4-node conforming plate predicts a saddles shape. Comparing the simulation results with ABAQUS, the RDKQ-NL20 element shows the best accuracy among all the elements.

Keywords: Bistable, finite element method, geometrical nonlinearity, quadrilateral plate elements

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Authors: Harrison Gideon Maghra

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The study was conducted on the challenges in the use of ICT in Agricultural Education and Training in Colleges of Education in Adamawa State. Three objectives guided the study, and the objectives were translated into three research questions and the research questions translated into two null hypotheses. Frequency and percentage were used to answer research question one, mean and standard deviation were used to answer research questions two and three, and t-test statistic was used to test the null hypotheses at 0.05 level of significance. The study was descriptive research and a questionnaire was used to solicit responses from the respondent. The instrument for data collection was subjected to face and content validity by 1 expert in the Department of Vocational Education, Modibbo Adama University, Yola and 3 experts from the Department of Vocational and Technical Education, Adamawa State University, Mubi. Pearson Product Moment Correlation Coefficient was used to test the reliability of the instrument and a reliability coefficient of 0.76 was obtained through the test re-test test method. Results from the study revealed that ICT facilities are not available in state-owned colleges of education. Agricultural Education lecturers have a positive attitude toward the use of ICT in teaching agricultural education and training. Based on the findings of the study, recommendations were made, among which: Colleges of Education in the state should organize training on the use of ICT for all lecturers, including those in the Agricultural Education program.

Keywords: challenges, ICT, agricultural education, colleges of education

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Authors: Hossein Kh. Bisheh, Nan Wu

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Advanced composite materials have a great importance in engineering structures due to their high specific modulus and strength and low weight. These materials can be used in design and fabrication of automotive drive shafts to reduce the weight of the structure. Hence, an optimum design of a composite drive shaft satisfying the design criteria, can be an appropriate substitution of metallic drive shafts. The aim of this study is to design and analyze a composite automotive drive shaft with high specific strength and low weight satisfying the design criteria. Tsai-Wu criterion is chosen as the failure criterion. Various designs with different lay-ups and materials are investigated based on the design requirements and finally, an optimum design satisfying the design criteria is chosen based on the weight and cost considerations. The results of this study indicate that if the weight is the main concern, a shaft made of Carbon/Epoxy can be a good option, and if the cost is a more important parameter, a hybrid shaft made of aluminum and Carbon/Epoxy can be considered.

Keywords: Bending natural frequency, Composite drive shaft, Peak torque, Torsional buckling

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Authors: Donna H. Gabor

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This study aimed to develop and validate an electronic module in physics for first-year college students of Iloilo and find out if there would be a significant difference in the performance of students before and after using the electronic module. The e-module was composed of one topic with two sub-lessons in linear motion (kinematics). The participants of the study were classified into three groups: the subject matter experts who are physics instructors who suggested the content, physical appearance, and limitations of the e-module; the IT experts who are active both in teaching and developing computer programs; and 28 students divided into two groups, 15 in the pilot group and 13 in the final test group. A researcher created 30 items checklist form (difficulty of a sample problem, comprehension, application, and definition of terms) was prepared and validated by the experts in subject matter for gathering data. To test the difference in student performance in physics, the researcher prepared an achievement test containing 25 items, multiple choices. The findings revealed that there was an increase in the performance of students in the pretest and post-test. T-test results revealed that there was a significant difference in the test scores of the students before and after using the module which can be used as a future reference for linear motion as an additional teaching tool in physics.

Keywords: electronic module, kinematics, linear motion, physics

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Authors: Behailu Shigute Habtemariam

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The aim of the study was to examine the effects of training load on some selected fitness performance variables of volleyball players in the case of U-17 female volleyball project players in the central Ethiopia region. Methods: In this study, quasi-experimental design was used. For the purpose of this study, twenty-three volleyball players were used as a subject from the two projects. The data collected through fitness performance assessment were analyzed and interpreted into a meaningful idea using manually as well as with computer in order to compare physical fitness variables and changes observed among participants. Those are taking part in the effects of training load on some selected physical fitness variables. The collected data were analyzed by means of the Statistical Package for Social Science version (SPSS V 20). The independent t-test was used to show the mean differences between the groups, and the paired T-test was used to compare the mean differences of the pre and post-training within each group. The level of significance will be set at Alfa 0.05. Results: The results are displayed using tables and figures. A significant difference was found in the mean differences of pre-test values (19.7 cm) and post-test values (37.5 cm) of the Durame city project on the flexibility test (MD =17.8 cm, P = 0.00). On the other hand, there was a significant difference in the mean difference of pre-test values of (18 cm) and post-test values (26.3 cm) of the Hosana city project on the flexibility test ( MD = 8.3 cm, P = 0.00). Conclusion: According to the results of the present studies, there were significant improvements from pre to post-test at Durame City and Hosana City projects on agility, flexibility, power, and speed fitness tests. On the other hand, a significant difference was not found before beginning the exercise between the two projects; however, a significant difference was found after 12 weeks of training.

Keywords: overload, performance, training, volleyball

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Authors: Nzereogu Stella Kosi, Igwe Ogbonnaya, Emeh Chukwuebuka Odinaka

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A comparative analysis of the expansion rate and soil erodibility of some gullies in Nnewi and Nnobi both of Nanka Formation were studied. The study involved an integration of field observations, geotechnical analysis, slope stability analysis, multivariate statistical analysis, gully expansion rate analysis, and determination of the soil erodibility factor (K) from Revised Universal Soil Loss Equation (RUSLE). Fifteen representative gullies were studied extensively, and results reveal that the geotechnical properties of the soil, topography, vegetation cover, rainfall intensity, and the anthropogenic activities in the study area were major factors propagating and influencing the erodibility of the soils. The specific gravity of the soils ranged from 2.45-2.66 and 2.54-2.78 for Nnewi and Nnobi, respectively. Grain size distribution analysis revealed that the soils are composed of gravel (5.77-17.67%), sand (79.90-91.01%), and fines (2.36-4.05%) for Nnewi and gravel (7.01-13.65%), sand (82.47-88.67%), and fines (3.78-5.02%) for Nnobi. The soils are moderately permeable with values ranging from 2.92 x 10-5 - 6.80 x 10-4 m/sec and 2.35 x 10-6 - 3.84 x 10⁻⁴m/sec for Nnewi and Nnobi respectively. All have low cohesion values ranging from 1–5kPa and 2-5kPa and internal friction angle ranging from 29-38° and 30-34° for Nnewi and Nnobi, respectively, which suggests that the soils have low shear strength and are susceptible to shear failure. Furthermore, the compaction test revealed that the soils were loose and easily erodible with values of maximum dry density (MDD) and optimum moisture content (OMC) ranging from 1.82-2.11g/cm³ and 8.20-17.81% for Nnewi and 1.98-2.13g/cm³ and 6.00-17.80% respectively. The plasticity index (PI) of the fines showed that they are nonplastic to low plastic soils and highly liquefiable with values ranging from 0-10% and 0-9% for Nnewi and Nnobi, respectively. Multivariate statistical analyses were used to establish relationship among the determined parameters. Slope stability analysis gave factor of safety (FoS) values in the range of 0.50-0.76 and 0.82-0.95 for saturated condition and 0.73-0.98 and 0.87-1.04 for unsaturated condition for both Nnewi and Nnobi, respectively indicating that the slopes are generally unstable to critically stable. The erosion expansion rate analysis for a fifteen-year period (2005-2020) revealed an average longitudinal expansion rate of 36.05m/yr, 10.76m/yr, and 183m/yr for Nnewi, Nnobi, and Nanka type gullies, respectively. The soil erodibility factor (K) are 8.57x10⁻² and 1.62x10-4 for Nnewi and Nnobi, respectively, indicating that the soils in Nnewi have higher erodibility potentials than those of Nnobi. From the study, both the Nnewi and Nnobi areas are highly prone to erosion. However, based on the relatively lower fine content of the soil, relatively lower topography, steeper slope angle, and sparsely vegetated terrain in Nnewi, soil erodibility and gully intensity are more profound in Nnewi than Nnobi.

Keywords: soil erodibility, gully expansion, nnewi-nnobi, slope stability, factor of safety

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Authors: Jiang Zhenbo, Ishikura Ryohei, Yasufuku Noriyuki

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Improvement of soft clay deposits by the combination of surface stabilization and floating type cement-treated columns is one of the most popular techniques worldwide. On the basis of one dimensional consolidation model, a time-dependent skin friction model for the column-soil interaction is proposed. The nonlinear relationship between column shaft shear stresses and effective vertical pressure of the surrounding soil can be described in this model. The influence of column-soil surface roughness can be represented using a roughness coefficient R, which plays an important role in the design of column length. Based on the homogenization method, a part of floating type improved ground will be treated as an unimproved portion, which with a length of αH1 is defined as a time-dependent equivalent skin friction length. The compression settlement of this unimproved portion can be predicted only using the soft clay parameters. Apart from calculating the settlement of this composited ground, the load transfer mechanism is discussed utilizing model tests. The proposed model is validated by comparing with calculations and laboratory results of model and ring shear tests, which indicate the suitability and accuracy of the solutions in this paper.

Keywords: floating type improved foundation, time-dependent skin friction, roughness, consolidation

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Authors: K. Benyounes, A. Benmounah

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Cement-based grouts has been used successfully to repair cracks in many concrete structures such as bridges, tunnels, buildings and to consolidate soils or rock foundations. In the present study, the rheological characterization of cement grout with water/binder ratio (W/B) is fixed at 0.5. The effect of the replacement of cement by bentonite (2 to 10 % wt) in presence of superplasticizer (0.5 % wt) was investigated. Several rheological tests were carried out by using controlled-stress rheometer equipped with vane geometry in temperature of 20°C. To highlight the influence of bentonite and superplasticizer on the rheological behavior of grout cement, various flow tests in a range of shear rate from 0 to 200 s-1 were observed. Cement grout showed a non-Newtonian viscosity behavior at all concentrations of bentonite. Three parameter model Herschel-Bulkley was chosen for fitting of experimental data. Based on the values of correlation coefficients of the estimated parameters, The Herschel-Bulkley law model well described the rheological behavior of the grouts. Test results showed that the dosage of bentonite increases the viscosity and yield stress of the system and introduces more thixotropy. While the addition of both bentonite and superplasticizer with cement grout improve significantly the fluidity and reduced the yield stress due to the action of dispersion of SP.

Keywords: rheology, cement grout, bentonite, superplasticizer, viscosity, yield stress

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Authors: Ovidiu Domşa, Nicolae Bold

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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: Wilfred Fritz

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Grid connected solar PV inverters need to be compliant to standard regulations regarding unwanted harmonic generation. This paper gives an introduction to harmonics, solar PV inverter voltage regulation and balancing through compensation and investigates the behaviour of harmonic generation at different power levels. Practical measurements of harmonics and power levels with a power quality data logger were made, on a test network at a university in Germany. The test setup and test results are discussed. The major finding was that between the morning and afternoon load peak windows when the PV inverters operate under low solar insolation and low power levels, more unwanted harmonics are generated. This has a huge impact on the power quality of the grid as well as capital and maintenance costs. The design of a single-tuned harmonic filter towards harmonic mitigation is presented.

Keywords: harmonics, power quality, pulse width modulation, total harmonic distortion

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Authors: Tünde Tifordiána Simonyi, Tímea Harmath-Tánczos

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The primary aim of the current research is to present the significance of a multicultural perspective in clinical neuropsychology and to present the test battery of the Multicultural Neuropsychological Scale (MUNS). The method includes the MUNS screening tool that involves stimuli common to most cultures in the world. The test battery measures general cognitive functioning focusing on five cognitive domains (memory, executive function, language, visual construction, and attention) tested with seven subtests that can be utilized within a wide age range (15-89), and lower and higher education participants. It is a scale that is sensitive to mild cognitive impairments. Our study presents the first results with the Hungarian translation of MUNS on a healthy sample. The education range was 4-25 years of schooling. The Hungarian sample was recruited by snowball sampling. Within the investigated population (N=151) the age curve follows an inverted U-shaped curve regarding cognitive performance with a high load on memory. Age, reading fluency, and years of education significantly influenced test scores. The sample was tested twice within a 14-49 days interval to determine test-retest reliability, which is satisfactory. Besides the findings of the study and the introduction of the test battery, the article also highlights its potential benefits for both research and clinical neuropsychological practice. The importance of adapting, validating and standardizing the test in other languages besides the Hungarian language context is also stressed. This test battery could serve as a helpful tool in mapping general cognitive functions in psychiatric and neurological disorders regardless of the cultural background of the patients.

Keywords: general cognitive functioning, multicultural, MUNS, neuropsychological test battery

Procedia PDF Downloads 104