Search results for: adaptive responses

Authors: Khoo Shin Yee, Lian Yee Cheng, Ong Zhi Chao, Zubaidah Ismail, Siamak Noroozi

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Structural frequency response testing is accurate in identifying the dynamic characteristic of a machinery structure. In practical perspective, conventional structural frequency response testing such as experimental modal analysis with impulse technique (also known as “impulse testing”) has limitation especially on its long acquisition time. The high acquisition time is mainly due to the redundancy procedure where the engineer has to repeatedly perform the test in 3 directions, namely the axial-, horizontal- and vertical-axis, in order to comprehensively define the dynamic behavior of a 3D structure. This is unfavorable to numerous industries where the downtime cost is high. This study proposes to reduce the testing time by using oblique impact. Theoretically, a single oblique impact can induce significant vibration responses and vibration modes in all the 3 directions. Hence, the acquisition time with the implementation of the oblique impulse technique can be reduced by a factor of three (i.e. for a 3D dynamic system). This study initiates an experimental investigation of impulse testing with oblique excitation. A motor-driven test rig has been used for the testing purpose. Its dynamic characteristic has been identified using the impulse testing with the conventional normal impact and the proposed oblique impact respectively. The results show that the proposed oblique impulse testing is able to obtain all the desired natural frequencies in all 3 directions and thus providing a feasible solution for a fast and time effective way of conducting the impulse testing.

Keywords: frequency response function, impact testing, modal analysis, oblique angle, oblique impact

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Authors: Gabi N. Nehme

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Below-knee amputees commonly experience asymmetrical gait patterns. It is generally believed that ischemia is related to the formation of pressure sores due to uneven distribution of forces. Micro-vascular responses can reveal local malnutrition. Changes in local skin blood supply under various external loading conditions have been studied for a number of years. Radionuclide clearance, photo-plethysmography, trans-cutaneous oxygen tension along with other studies showed that the blood supply would be influenced by the epidermal forces, and the rate and the amount of blood supply would decrease with increased epidermal loads being shear forces or normal forces. Several cases of socket designs were investigated using Finite Element Model (FEM) and Design of Experiment (DOE) to increase flexibility and minimize the pressure at the limb/socket interface using ultra high molecular weight polyethylene (UHMWPE) and polyamide 6 (PA6) or Duraform. The pressure reliefs at designated areas where reducing thickness is involved are seen to be critical in determination of amputees’ comfort and are very important to clinical applications. Implementing a hole between the Patellar Tendon (PT) and Distal Tibia (DT) would decrease stiffness and increase prosthesis range of motion where flexibility is needed. In addition, displacement and prosthetic energy storage increased without compromising mechanical efficiency and prosthetic design integrity.

Keywords: patellar tendon, distal tibia, prosthetic socket relief areas, hole implementation

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Authors: E. M. Hassan, A. L. Kalamkarov

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Two micromechanical models for 3D smart composite with embedded periodic or nearly periodic network of generally orthotropic reinforcements and actuators are developed and applied to cubic structures with unidirectional orientation of constituents. Analytical formulas for the effective piezothermoelastic coefficients are derived using the Asymptotic Homogenization Method (AHM). Finite Element Analysis (FEA) is subsequently developed and used to examine the aforementioned periodic 3D network reinforced smart structures. The deformation responses from the FE simulations are used to extract effective coefficients. The results from both techniques are compared. This work considers piezoelectric materials that respond linearly to changes in electric field, electric displacement, mechanical stress and strain and thermal effects. This combination of electric fields and thermo-mechanical response in smart composite structures is characterized by piezoelectric and thermal expansion coefficients. The problem is represented by unit-cell and the models are developed using the AHM and the FEA to determine the effective piezoelectric and thermal expansion coefficients. Each unit cell contains a number of orthotropic inclusions in the form of structural reinforcements and actuators. Using matrix representation of the coupled response of the unit cell, the effective piezoelectric and thermal expansion coefficients are calculated and compared with results of the asymptotic homogenization method. A very good agreement is shown between these two approaches.

Keywords: asymptotic homogenization method, finite element analysis, effective piezothermoelastic coefficients, 3D smart network composite structures

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Authors: B. Parchem, M. Watanabe, D. Modrakovic, L. Mathew, A. Franklin, M. Cao, R. E. Broudy

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Objective: Executive functioning (EF) deficits underlie several mental health diagnoses including ADHD, anxiety, and depression. Community mental health clinics face extensive waitlists for services with many referrals involving EF deficits. A pilot trial of a four-week group therapy was developed using key components from Cognitive-Behavioral Therapy (CBT), Dialectical Behavior Therapy (DBT), and mindfulness with an aim to improve EF skills and offer low-fee services. Method: Eight adults (M = 34.5) waiting for services at a community clinic were enrolled in a four-week group therapy at an in-house training clinic for doctoral trainees. Baseline EF, pre-/post-intervention ADHD and distress symptoms, group satisfaction, and curriculum helpfulness were assessed. Results: Downward trends in ADHD and distress symptoms pre/post-intervention were not significant. Favorable responses on group satisfaction and helpfulness suggest clinical utility. Conclusion: Preliminary pilot data from a brief group therapy to improve EF may be an efficacious, acceptable, and feasible intervention for adults waiting for services at community mental health and training clinics where there are high demands and limits to services and staffs.

Keywords: executive functioning, cognitive-behavioral therapy, dialectical behavior therapy, mindfulness, adult group therapy

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Authors: Ghanim A. Bekr

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Project success is what must be done for the project to be acceptable to the client, stakeholders and end-users who will be affected by the project. The study of project success and the critical success factors (CSFs) are the means adopted to improve the effectiveness of project. This research is conducted to make an attempt to identify which variables influence the success of project implementation. This study has selected, through an extensive literature review and interviews, (83) factors categorized in (7) groups that the questionnaire respondents were asked to score. The responses from 66 professionals with an average of 15 years of experience in different types of construction projects in Jordan were collected and analyzed using SPSS and most important factors for success for various success criteria are presented depending on the relative importance index to rank the categories. The research revealed the significant groups of factors are: Client related factors, Contractor’s related factors, Project Manager (PM) related factors, and Project management related factors. In addition the top ten sub factors are: Assertion of the client towards short time of the project, availability of skilled labor, Assertion of the client towards high level of the quality, capability of the client in taking risk, previous experience of the PM in similar projects, previous experience of the contractor in similar projects, decision making by the client/ the client’s representative at the right time, assertion of client towards low cost of project, experience in project management in previous projects, and flow of the information among parties. The results would be helpful to construction project professionals in taking proactive measures for successful completion of construction projects in Jordan.

Keywords: construction projects, critical success factors, Jordan, project success

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Authors: Umego Chukwudi T., Ntui Valentine O., Uyoh Edak A.

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Phosphorus (P) deficiency has been identified as a major hindrance to rice production the world over. Eleven (11) rice genotypes predominantly used by local farmers in Nigeria were studied for their responses to P deficient conditions. The characterization was based on morpho-physiologic parameters. The genotypes were screened using a hydroponic system in a modified Hoagland’s solution. Morphological and physiologic parameters, including Plant height (PH), number of tillers per plant, shoot dry weight (SDW), shoot phosphate concentration (SPC), and chlorophyll content, were recorded after exposure to three levels of phosphate concentration (0µM, 400 µM, and 800 µM). The data obtained were subjected to analysis of variance (ANOVA), and the means were separated using least significance difference tests. The results obtained showed that P starvation caused a significant (p≤0.05) reduction in PH, SDW, and tillering and also triggered a significant (p≤0.05) increase in root length among the genotypes. The Pearsons correlation coefficient was used to estimate the relationships among studied parameters, and a significant negative correlation was observed between plant height and root length. FARO63 was identified as a highly tolerant genotype to P deficiency with a low (0.24) SPC and higher (4.81) phosphate utilization efficiency (PUE). This study has identified FARO63 as a true tolerant genotype to Phosphate deficiency, which will be useful in breeding for phosphate deficiency tolerance in rice and thus combating food insecurity.

Keywords: phosphate deficiency, rice genotypes, hydroponic system, food security

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Authors: Ehsan Mehryaar, Seyed Armin Motahari Tabari

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Coarse-grained soils are known and commonly used in a wide range of geotechnical projects, including high earth dams or embankments for their high shear strength. The most important engineering property of these soils is friction angle which represents the interlocking between soil particles and can be applied widely in designing and constructing these earth structures. Friction angle and dilative behavior of coarse-grained soils can be estimated from empirical correlations with in-situ testing and physical properties of the soil or measured directly in the laboratory performing direct shear or triaxial tests. Unfortunately, large-scale testing is difficult, challenging, and expensive and is not possible in most soil mechanic laboratories. So, it is common to remove the large particles and do the tests, which cannot be counted as an exact estimation of the parameters and behavior of the original soil. This paper describes a new methodology to simulate particles grading distribution of a well-graded gravel sample to a smaller scale sample as it can be tested in an ordinary direct shear apparatus to estimate the stress-strain behavior, friction angle, and dilative behavior of the original coarse-grained soil considering its confining pressure, and relative density using a machine learning method. A total number of 72 direct shear tests are performed in 6 different sizes, 3 different confining pressures, and 4 different relative densities. Multivariate Adaptive Regression Spline (MARS) technique was used to develop an equation in order to predict shear strength and dilative behavior based on the size distribution of coarse-grained soil particles. Also, an uncertainty analysis was performed in order to examine the reliability of the proposed equation.

Keywords: MARS, coarse-grained soil, shear strength, uncertainty analysis

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Authors: Hashem Shariatmadar, Mozhgansadat Momtazdargahi

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The purpose of control structure against earthquake is to dissipate earthquake input energy to the structure and reduce the plastic deformation of structural members. There are different methods for control structure against earthquake to reduce the structure response that they are active, semi-active, inactive and hybrid. In this paper two different combined control systems are used first system comprises base isolator and multi tuned mass dampers (BI & MTMD) and another combination is hybrid base isolator and multi tuned mass dampers (HBI & MTMD) for controlling an eight story isolated benchmark steel structure. Active control force of hybrid isolator is estimated by fuzzy logic algorithms. The influences of the combined systems on the responses of the benchmark structure under the two near-field earthquake (Newhall & Elcentro) are evaluated by nonlinear dynamic time history analysis. Applications of combined control systems consisting of passive or active systems installed in parallel to base-isolation bearings have the capability of reducing response quantities of base-isolated (relative and absolute displacement) structures significantly. Therefore in design and control of irregular isolated structures using the proposed control systems, structural demands (relative and absolute displacement and etc.) in each direction must be considered separately.

Keywords: base-isolated benchmark structure, multi-tuned mass dampers, hybrid isolators, near-field earthquake, fuzzy algorithm

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Authors: Ramesh Nagarajappa, Upasana Mohapatra

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Considered a modern phobia, Nomophobia (NO MObile PHOne PhoBIA) is a term that describes the irrational fear or anxiety of being unable to access one’s own mobile phone. Objectives: To develop and validate the nomophobia questionnaire, administering it to a sample of adolescents representing undergraduate dental students. To assess the prevalence of Nomophobia, determine the usage pattern of mobile phones, and evaluate the impact due to lack of access to mobile phones among undergraduate dental students. Methodology: A cross-sectional study was conducted on 302 undergraduate students at Bhubaneswar through a self-administered questionnaire via Google Forms consisting of 19 items evaluating the pattern and anxiety related to usage of mobile phones. Responses were recorded on a 5-point Likert scale. Kruskal Wallis, Mann-Whitney U, and Chi-square tests were used for statistical analysis. Results: Test-Retest reliability showed kappa of k=0.86 and Internal consistency Chronbach’s-Alpha to be α=0.82. Prevalence of nomophobia (score ≥ 58) was 32.1%, and students at risk of being nomophobic (score 39-57) was 61.9%. It was highest in males (32.6%) and amongst the interns (41.9%) and lowest (25.5%) amongst the second-year students. Participants felt nervous/insecure if their phones were away from them because of the fear that somebody might have accessed their data (3.07±1.93) and or tried to contact them (3.09±1.13), which were not statistically significant (p>0.05). Conclusions: Effect of mobile phone on dental students and the fear of not having their phones with them is increasing elaborately, that needs to be controlled, which if not achieved, would negatively hamper their academic performance and their being in the society.

Keywords: addiction, dental students, mobile phone, nomophobia

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Authors: A. Swetha

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This study aims to prioritize and explore critical risks in construction project assessment, employing the Weighted Average Index method and Principal Component Analysis (PCA). Through extensive literature review and expert interviews, project assessment risk factors were identified across Budget and Cost Management Risk, Schedule and Time Management Risk, Scope and Planning Risk, Safety and Regulatory Compliance Risk, Resource Management Risk, Communication and Stakeholder Management Risk, and Environmental and Sustainability Risk domains. A questionnaire was distributed to stakeholders involved in construction activities in Hyderabad, India, with 180 completed responses analyzed using the Weighted Average Index method to prioritize risk factors. Subsequently, PCA was used to understand relationships between these factors and uncover underlying patterns. Results highlighted dependencies on critical resources, inadequate risk assessment, cash flow constraints, and safety concerns as top priorities, while factors like currency exchange rate fluctuations and delayed information dissemination ranked lower but remained significant. These insights offer valuable guidance for stakeholders to mitigate risks effectively and enhance project outcomes. By adopting systematic risk assessment and management approaches, construction projects in Hyderabad and beyond can navigate challenges more efficiently, ensuring long-term viability and resilience.

Keywords: construction project assessment risk factor, risk prioritization, weighted average index, principal component analysis, project risk factors

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Authors: Meysam Naeimi, Zili Li, Roumen Petrov, Rolf Dollevoet, Jilt Sietsma, Jun Wu

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The substantial similarity of fatigue mechanism in a new test rig for rolling contact fatigue (RCF) has been investigated. A new reduced-scale test rig is designed to perform controlled RCF tests in wheel-rail materials. The fatigue mechanism of the rig is evaluated in this study using a combined finite element-fatigue prediction approach. The influences of loading conditions on fatigue crack initiation have been studied. Furthermore, the effects of some artificial defects (squat-shape) on fatigue lives are examined. To simulate the vehicle-track interaction by means of the test rig, a three-dimensional finite element (FE) model is built up. The nonlinear material behaviour of the rail steel is modelled in the contact interface. The results of FE simulations are combined with the critical plane concept to determine the material points with the greatest possibility of fatigue failure. Based on the stress-strain responses, by employing of previously postulated criteria for fatigue crack initiation (plastic shakedown and ratchetting), fatigue life analysis is carried out. The results are reported for various loading conditions and different defect sizes. Afterward, the cyclic mechanism of the test rig is evaluated from the operational viewpoint. The results of fatigue life predictions are compared with the expected number of cycles of the test rig by its cyclic nature. Finally, the estimative duration of the experiments until fatigue crack initiation is roughly determined.

Keywords: fatigue, test rig, crack initiation, life, rail, squats

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Authors: Medine Baran, Abdulkadir Maskan, Mehmet Ikbal Yetişir, Mukadder Baran, Azmi Türkan, Şeyma Yaşar

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The purpose of this study was to determine the views of physics teachers from several secondary schools in Turkey towards context-based learning approach. In the study, the context-based learning opinion questionnaire developed by the researchers for use as the data collection tool was piloted with 250 physics teachers. The questionnaire examined by the researchers and field experts was initially made up of 53 items. Following the evaluation process of the questionnaire, it included 37 items. In this way, the reliability and validity process of the measurement tool was completed. In the end, the finalized questionnaire was applied to 144 physics teachers from several secondary schools in different cities in Turkey (F:73, M:71). In the study, the participants were determined based on ease of reaching them. The results revealed no remarkable difference between the views of the physics teachers with respect to their gender, region and school. However, when the items in the questionnaire were considered, it was found that the participants interestingly agreed on some of the choices in the items. Depending on this, it was found that there were high levels of differences between the frequencies of those who agreed and those who disagreed with the 16 items in the questionnaire. Therefore, as the following phase of the present study, further research has been planned using the same questions. Based on these questions, which received opposite responses, physics teachers will be asked for their views about the results of the study using the interview technique, one of qualitative research techniques. In this way, the results will be evaluated both by the researchers and by the participants, and the problems and difficulties will be determined. As a result, related suggestions can be put forward.

Keywords: context bases learning, physics teachers, views

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Authors: Mahlet Nigussie Worku

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The main purpose of this study was to examine the effects of different leadership styles on employee engagement in Ethiopian Airlines head quarter located in Addis Ababa. Specific objectives of the study were stated to examine the effects of five leadership styles namely transformational, transactional, democratic, lassies fair and autocratic leadership styles on employees’ engagement. The study was conducted on 288 sample size and a simple random sampling technique was employed. The quantitative findings were presented and analyzed by table, ANOVA, bivariate correlation and regression model through SPSS software version 23. Out of 288 total distributed questionnaires 280 were returned and 8 of the returned were rejected due to missing data while the remaining 280 responses were used for data analysis. Data was analyzed using the Statistical Package for Social Sciences (SPSS). The study employed both descriptive and explanatory research design. Correlation and regression were used to analyze the relationship and its effect between leadership Style and employee’s engagement. The regression results showed that transformational, transactional and democratic leadership Styles have significant contribution for employee’s engagement. Similarly transformational, transactional land democratic leadership style had a positive and strong correlation with employee’s engagement. However lassies-fair and autocratic leadership style showed negative and insignificant effect on employee engagement. Finally, based on the findings, workable recommendations and implications for further studies were forwarded

Keywords: leadership, leadership style, employee engagement, autocratic leadership styles

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Authors: Nasreen Basoudan, Andrea Tales, Frederic Boy

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Non-clinical anxiety may be comprised of state anxiety - temporarily experienced anxiety related to a specific situation, and trait anxiety - a longer lasting response or a general disposition to anxiety. While temporary and occasional anxiety whether as a mood state or personality dimension is normal, nonclinical anxiety may influence many more components of information processing than previously recognized. In ageing and dementia-related research, disease characterization now involves attempts to understand a much wider range of brain function such as loss of inhibitory control, as against the more common focus on memory and cognition. However, in many studies, the tendency has been to include individuals with clinical anxiety disorders while excluding persons with lower levels of state or trait anxiety. Loss of inhibitory cognitive control can lead to behaviors such as aggression, reduced sensitivity to others, sociopathic thoughts and actions. Anxiety has also been linked to inhibitory control, with research suggesting that people with anxiety are less capable of inhibiting their emotions than the average person. This study investigates the relationship between anxiety and loss of inhibitory control in younger and older adults, using a variety of questionnaires and computers-based tests. Based on the premise that irrespective of classification, anxiety is associated with a wide range of physical, affective, and cognitive responses, this study explores evidence indicative of the potential influence anxiety per se on loss of inhibitory control, in order to contribute to discussion and appropriate consideration of anxiety-related factors in methodological practice.

Keywords: anxiety, ageing, dementia, inhibitory control

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Authors: Raymond Li

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In this project a web-based classroom response system (CRS) was used in the teaching an intermediate level economics course. This system allows the instructor to post a question on the screen and students to answer questions using their own electronic mobile devices. The questions and the results summarizing student responses can be shown to students simultaneously and the instructor can make timely feedback to students in class. CRS gives students a chance to respond to the instructor’s question privately, encouraging students who might not typically speak up in class to express their thoughts and opinions. There is a vast literature on the advantages and challenges of using CRS. However, empirical evidence on the student attributes that increase the effectiveness of CRS in improving student learning outcomes is sparse. The purpose of this project is to (1) find out if the use of CRS is beneficial to students taking economics, and (2) discover key student attributes that will likely make CRS more effective. Students’ performance in examinations and an end-of-semester questionnaire were used to assess the effectiveness of CRS in this project. Comparing the examination scores of the CRS treatment group and control group, the treatment group performed considerably better and statistically significant differences were found basing on paired t-tests on the differences. According to the questionnaire results, around 75% of the students in the treatment group generally agreed that CRS allowed them to express their views more freely. We also observed that students who prefer to use instant messaging rather than making conversations are generally more positive towards CRS. The use of CRS also benefits the instructor – students’ rating of the instructor in the teaching evaluation was significantly higher for the CRS treatment group.

Keywords: education technology, classroom response system, student attributes, economics education

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Authors: Barzan Hadi Hama Karim

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In recent years, an increasing number of faculties and colleges of basic education are established by the universities and ministry of Higher Education and Scientific Research of Iraqi Kurdistan to graduate English teachers to teach in the basic and high schools. One central consideration of this study is to what extent graduate teachers receive adequate preparation from these faculties and college of basic education. An important program which is offered in the department of English language in these colleges and faculties is Viewing and Practicing. The purpose of this research is to explore how students of basic education colleges and faculties are using the program of Viewing and Practicing to support the educational process. This study provides a general framework about educational uses of the program as a pedagogical tool to teach English Language in the basic schools and describes the different perceptions of the students at the final stage of their education. A survey is used to collect responses from a group of students to determine their expectations and perceptions about the program. The results display that the program has several aspects of strengths, such as improving English teaching and speaking proficiency, cultivating subject knowledge related to applied linguistics and promoting research engagement. The findings of the study address the following questions: Is Viewing and Practicing Program beneficial for students to experience English language for future career at schools? To what extent do the students prefer teaching English Language in the schools?

Keywords: teaching experience, viewing and practicing, perception, expectation

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Authors: Abdoulahad Allamine

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The objective of this study is to assess the impact of climate variability on agriculture and food security in 43 countries of sub-Saharan Africa. We use for this purpose the data from BADC bases, UNCTAD, and WDI FAOSTAT to estimate a VAR model on panel data. The sample is divided into three (03) agro-climatic zones, more explicitly the equatorial zone, the Sahel region and the semi-arid zone. This allows to highlight the differential impacts sustained by countries and appropriate responses to each group of countries. The results show that the sharp fluctuations in the volume of rainfall negatively affect agriculture and food security of countries in the equatorial zone, with heavy rainfall and high temperatures in the Sahel region. However, countries with low temperatures and low rainfall are the least affected. The hedging policies against the risks of climate variability must be more active in the first two groups of countries. On this basis and in general, we recommend integration of agricultural policies between countries is done to reduce the effects of climate variability on agriculture and food security. It would be logical to encourage regional and international closer collaboration on the development and dissemination of improved varieties, ecological intensification, and management of biotic and abiotic stresses facing these climate variability to sustainably increase food production. Small farmers also need training in agricultural risk hedging techniques related to climate variations; this requires an increase in state budgets allocated to agriculture.

Keywords: agro-climatic zones, climate variability, food security, Sub-Saharan Africa, VAR on panel data

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Authors: Paweł Żur, Alicja Żur, Andrzej Baier

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Modal analysis is a crucial tool in the field of engineering for understanding the dynamic behavior of structures. In this study, numerical modal analysis was conducted on a multi-material 3D-printed composite bushing, which comprised a polylactic acid (PLA) outer shell and a thermoplastic polyurethane (TPU) flexible filling. The objective was to investigate the modal characteristics of the bushing and assess its potential for practical applications. The analysis involved the development of a finite element model of the bushing, which was subsequently subjected to modal analysis techniques. Natural frequencies, mode shapes, and damping ratios were determined to identify the dominant vibration modes and their corresponding responses. The numerical modal analysis provided valuable insights into the dynamic behavior of the bushing, enabling a comprehensive understanding of its structural integrity and performance. Furthermore, the study expanded its scope by investigating the entire shaft mounting of a small electric car, incorporating the 3D-printed composite bushing. The shaft mounting system was subjected to numerical modal analysis to evaluate its dynamic characteristics and potential vibrational issues. The results of the modal analysis highlighted the effectiveness of the 3D-printed composite bushing in minimizing vibrations and optimizing the performance of the shaft mounting system. The findings contribute to the broader field of composite material applications in automotive engineering and provide valuable insights for the design and optimization of similar components.

Keywords: 3D printing, composite bushing, modal analysis, multi-material

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Authors: Alaa A. Al-Harthi, Abdulrahman S. Bageis, Bingunath Ingirige

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Poor levels of performance and low productivity were highlighted by many previous studies as a major cause of failure in the Saudi construction industry. This paper provides recommendations to address key external indicators that led to poor levels of performance and low productivity in Engineering and Technical Departments (ETDs) within the Saudi governmental agencies. The ETDs are client’s representative on behalf of the Saudi Ministries. This paper represents a part of an investigation which contained external and internal challenges that led to occurrence of the research problem. The paper is focusing on the external challenges which contain 14 indicators. These 14 external indicators had been examined carefully through comprehensive review of the literature then have been tested through quantitative and qualitative methods. 400 questionnaires were distributed to dozens of different bodies. The actual response rate was 47% completed responses. Four semi-structured interviews were conducted with senior practitioners from the Public Construction Sector. The finding showed that the 14 external indicators directly and/or indirectly influence the Public Construction Sector. It was noticed significantly that these indicators have prevented the ETDs from performing properly. It was also found that the 14 external indicators were constant with all kinds of Government Construction Projects in the Saudi context. Addressing the 14 external indicators requires to be planned over the long run which is responsible by relevant Saudi governmental authorities under the umbrella of the Saudi Council of Ministers. The study recommends that Project Management Office (PMO) should be considered in order to improve the performance of the ETDs.

Keywords: construction projects' performance, low engineering productivity, public construction sector

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Authors: Jaypee Limueco

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This research focused on the impact of Peer Instruction and PhET Simulations on the level of motivation and Physics anxiety of Grade 9 students. Two groups of students were used in the study. The experimental group involved 65 registered students while the control group has 64 registered students. To determine the level of motivation of students in learning physics, the Physics Motivation Questionnaire was administered. On the other hand, to determine the level of Physics anxiety of the students in each group, Physics Anxiety Rating Scale was used. Peer Instruction supplemented with PhET simulations was implemented in the experimental group while the traditional lecture method was used in the control group. Both instruments were again administered after the implementation of the two different teaching approaches. “Wilcoxon Signed Rank test” was used to test the significant difference between pretest and posttest of each group. “Mann Whitney U” was used to test if significant differences exist between each group before and after instruction. Results showed that there is no significant difference between the level of motivation and anxiety of the experimental and control group before the implementation at p<0.05 significance level. It implies that the students have the same level of motivation and physics anxiety before instruction. However, the results of both tests have significant differences between the groups after instruction. It is also found that there is a significant positive change in the responses of the students in the experimental group while no change was evident on the control. The result of the analysis of the Mann Whitney U shows that the change in the attributes of the students is caused by the treatment. Therefore, it is concluded that Peer Instruction and PhET simulation helped in alleviating motivation of students and minimizing their anxiety towards Physics.

Keywords: anxiety, motivation, peer instruction, PhET simulations

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Authors: David Koren, Vojko Kilar

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The modern energy-efficient houses are often founded on a thermal insulation (TI) layer placed under the building’s RC foundation slab. The purpose of the paper is to identify the potential problems of the buildings founded on TI layer from the seismic point of view. The two main goals of the study were to assess the seismic behavior of such buildings, and to search for the critical structural parameters affecting the response of the superstructure as well as of the extruded polystyrene (XPS) layer. As a test building a multi-storeyed RC frame structure with and without the XPS layer under the foundation slab has been investigated utilizing nonlinear dynamic (time-history) and static (pushover) analyses. The structural response has been investigated with reference to the following performance parameters: i) Building’s lateral roof displacements, ii) Edge compressive and shear strains of the XPS, iii) Horizontal accelerations of the superstructure, iv) Plastic hinge patterns of the superstructure, v) Part of the foundation in compression, and vi) Deformations of the underlying soil and vertical displacements of the foundation slab (i.e. identifying the potential uplift). The results have shown that in the case of higher and stiff structures lying on firm soil the use of XPS under the foundation slab might induce amplified structural peak responses compared to the building models without XPS under the foundation slab. The analysis has revealed that the superstructure as well as the XPS response is substantially affected by the stiffness of the foundation slab.

Keywords: extruded polystyrene (XPS), foundation on thermal insulation, energy-efficient buildings, nonlinear seismic analysis, seismic response, soil–structure interaction

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Authors: Charlene Petersen, Herman Grobler, Karel Botha

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Restorative intervention with adolescents from a family violence context is a much needed resource given the limited access to mental health services in South Africa. In this research article the qualitative component which formed part of a mixed methods design of an overall research study, is discussed. A qualitative case study design was used. This article explores a psycho-education strategy, using a visual creative medium as a method for reconstructing identity in the context of family violence. The aim of this psycho-education strategy was to move away from interventions based on the biomedical model, but focused more on meaning-making about violent traumatic events adolescents have experienced, and to develop more positive, adaptive views about themselves in the present, and experience hope about the future. The research question that was asked was how the meaning, that adolescents from a specific community in South Africa give to family violence, contribute to defining their identity? Twelve participants were purposively selected for the study and included both male and female adolescents with ages ranging from 15 to 18 years from three secondary schools. The strategy was applied over five sessions with the intention to bring about awareness of different selves, identifying and naming the selves, and becoming aware of the configuration of identity that could lead to a redefined identity. The data were thematically and visually analyzed. Through the process of tailoring which forms the basis for reconstruction process, participants could identify the different selves, become aware of how they configure in the field. Through the process of tailoring the different self-parts, the sense of self became more self-cohesive and allowed the individual to become aware of the role of certain. Through identifying and naming the future self and resilient self the participants were able to accomplish some order and meaning in their lives. It provided them with a sense of predictability and an optimistic and hopefulness towards the future. The research findings indicated that this strategy can be used as a method for reconstructing identity in the context of family violence.

Keywords: identity, family violence, self-configuration, reconstructing identity, psycho-education strategy

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Authors: Jeongil Kim

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The present study examined the effects of arts-mediated mother-child dyads mindfulness-based intervention for Korean children with attention deficit hyperactivity disorder (ADHD) and their mothers, on behaviors in children and subjective psychological states in mothers. Four elementary school boys with ADHD and their mothers participated in the study. Using a multiple baseline design across four mother-child dyads, data were collected on the target behaviors (disruptive behavior, on-task behavior, and compliance in class) in children using a 10-second partial interval recording system and on the subjective psychological states in mothers using four questionnaires (on perceived stress, burnout, mindfulness, and satisfaction with life). The intervention consisted of a) mindfulness training, b) mindfulness practice, and c) mindful management of body and feeling. The arts activities, making a coiled clay pot and Korean traditional music performance, were utilized to facilitate the environment to help each participant to understand the content and progress of the intervention program. The results showed that all four dyads showed improvement in adaptive behaviors in the children (increase in on-task behavior; decrease in disruptive behavior) and positive change in subjective psychological states in the mothers (increase in scores of mindfulness and satisfaction with life; decrease in scores of perceived stress and burnout). The changes in the children’s behaviors and in the mothers’ subjective psychological states were maintained when the intervention was drawn and generalized in novel settings. The results suggest that arts-mediated mother-child dyads mindfulness-based intervention would be a mutual benefiting strategy to support both children with ADHD and their mothers who experience diverse challenges in behavioral and psychological aspects.

Keywords: mindfulness, attention deficit hyperactivity disorder (ADHD), arts-mediated, behavior, psychological well-being, child-mother

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Authors: Judith Mogouong, Philippe Constant, Robert Lavallee, Claude Guertin

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The emerald ash borer (EAB) is an exotic wood borer insect native from China, which is associated with important environmental and economic damages in North America. Beetles are known to be vectors of microbial communities related to their adaptive capacities. It is now established that environmental stress factors may induce physiological events on the host trees, such as phytochemical changes. Consequently, that may affect the establishment comportment of herbivorous insect. Considering the number of insects collected on ash trees (insects’ density) as an abiotic factor related to stress damage, the aim of our study was to explore the dynamic of EAB gut microbial community genome (microbiome) when facing that factor and to monitor its diversity. Insects were trapped using specific green Lindgren© traps. A gradient of the captured insect population along the St. Lawrence River was used to create three levels of insects’ density (low, intermediate, and high). After dissection, total DNA extracted from insect guts of each level has been sent for amplicon sequencing of bacterial 16S rRNA gene and fungal ITS2 region. The composition of microbial communities among sample appeared largely diversified with the Simpson index significantly different across the three levels of density for bacteria. Add to that; bacteria were represented by seven phyla and twelve classes, whereas fungi were represented by two phyla and seven known classes. Using principal coordinate analysis (PCoA) based on Bray Curtis distances of 16S rRNA sequences, we observed a significant variation between the structure of the bacterial communities depending on insects’ density. Moreover, the analysis showed significant correlations between some bacterial taxa and the three classes of insects’ density. This study is the first to present a complete overview of the bacterial and fungal communities associated with the gut of EAB base on culture-independent methods, and to correlate those communities with a potential stress factor of the host trees.

Keywords: gut microbiome, DNA, 16S rRNA sequences, emerald ash borer

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Authors: Soultana Konstantinidou, Tiziana Schmidt, Elena Landi, Alessandro De Carli, Giovanni Maltinti, Darius Witt, Alicja Dziadosz, Agnieszka Lindstaedt, Michele Lai, Mauro Pistello, Valentina Cappello, Luciana Dente, Chiara Gabellini, Piotr Barski, Vittoria Raffa

Abstract:

CRISPR/Cas9 technology has gained the interest of researchers in the field of biotechnology for genome editing. Since its discovery as a microbial adaptive immune defense, this system has been widely adopted and is acknowledged for having a variety of applications. However, critical barriers related to safety and delivery are persisting. Here, we propose a new concept of genome engineering, which is based on a nano-formulation of Cas9. The Cas9 enzyme was conjugated to a gold nanoparticle (AuNP-Cas9). The AuNP-Cas9 maintained its cleavage efficiency in vitro, to the same extent as the ribonucleoprotein, including non-conjugated Cas9 enzyme, and showed high gene editing efficiency in vivo in zebrafish embryos. Since CRISPR/Cas9 technology is extensively used in cancer research, melanoma was selected as a validation target. Cell studies were performed in A375 human melanoma cells. Particles per se had no impact on cell metabolism and proliferation. Intriguingly, the AuNP-Cas9 internalized spontaneously in cells and localized as a single particle in the cytoplasm and organelles. More importantly, the AuNP-Cas9 showed a high nuclear localization signal. The AuNP-Cas9, overcoming the delivery difficulties of Cas9, could be used in cellular biology and localization studies. Taking advantage of the plasmonic properties of gold nanoparticles, this technology could potentially be a bio-tool for combining gene editing and photothermal therapy in cancer cells. Further work will be focused on intracellular interactions of the nano-formulation and characterization of the optical properties.

Keywords: CRISPR/Cas9, gene editing, gold nanoparticles, nanotechnology

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Authors: Ben Abderrahmane Ayoub El Fateh, Bnina Rachid

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A comprehensive comparison of antioxidant defenses in the dermis and epidermis and their response to exposure to ultraviolet (UV) irradiation has not previously been attempted. In this study, enzymic and non-enzymic antioxidants in epidermis and dermis of hairless mice were compared. Enzyme activities are presented both as units/gram of skin and units/milligram of protein; arguments are presented for the superiority of skin wet weight as a reference base. Catalase, glutathione peroxidase, and glutathione reductase (units/gram of skin) were higher in the epidermis than dermis by 49%, 86%, and 74%, respectively. Superoxide dismutase did not follow this pattern. Lipophilic antioxidants ( -tocopherol, ubiquinol 9, and ubiquinone 9) and hydrophilic antioxidants (ascorbic acid, dehydroascorbic acid, and glutathione) were 24–95% higher in the epidermis than in dermis. In contrast, oxidized glutathione was 60% lower in the epidermis than in dermis. Mice were irradiated with solar light to examine the response of these cutaneous layers to UV irradiation. After irradiation with 25 J/cm2 (UVA + UVB, from a solar simulator), 10 times the minimum erythemal dose, epidermal and dermal catalase and superoxide dismutase activities were greatly decreased. Tocopherol, ubiquinol 9, ubiquinone 9, ascorbic acid, dehydroascorbic acid, and reduced glutathione decreased in both epidermis and dermis by 26-93%. Oxidizedgiutathione showed a slight, non-significant increase. Because the reduction in total ascorbate and catalase was much more severe in the epidermis than dermis, it can be concluded that UV light is more damaging to the antioxidant defenses in the epidermis than in the dermis.

Keywords: antioxidant defenses, enzymic, epidermis, oxidizedgiutathione

Procedia PDF Downloads 433

Authors: Chaomeng Liu, Li Li, Xiao Wang, Li Ren, Qinge Zhang

Abstract:

Late-life depression (LLD) is a prevalent mental disorder among the elderly, frequently accompanied by significant cognitive decline, and has emerged as a worldwide public health concern. Microglia, astrocytes, and peripheral immune cells play pivotal roles in regulating inflammatory responses within the central nervous system (CNS) across diverse cerebral disorders. This review commences with the clinical research findings and accentuates the recent advancements pertaining to microglia and astrocytes in the neuroinflammation process of LLD. The reciprocal communication network between the CNS and immune system is of paramount importance in the pathogenesis of depression and cognitive decline. Stress-induced downregulation of tight and gap junction proteins in the brain results in increased blood-brain barrier permeability and impaired astrocyte function. Concurrently, activated microglia release inflammatory mediators, initiating the kynurenine metabolic pathway and exacerbating the quinolinic acid/kynurenic acid imbalance. Moreover, the balance between Th17 and Treg cells is implicated in the preservation of immune homeostasis within the cerebral milieu of individuals suffering from LLD. The ultimate objective of this review is to present future strategies for the management and treatment of LLD, informed by the most recent advancements in research, with the aim of averting or postponing the onset of AD.

Keywords: neuroinflammation, late-life depression, microglia, astrocytes, central nervous system, blood-brain barrier, Kynurenine pathway

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Authors: Volker Koch, Sigrid Swobodnik, Bernd M. Zunk

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The success of companies on globalized markets is significantly influenced by the performance of purchasing departments and, of course, the individuals employed as professional purchasers. Nonetheless, this is generally accepted in practice, in literature as well as in empirical research, only insufficient attention was given to the assessment of this relationship between the personality of professional purchasers and their individual performance. This paper aims to describe the relationship against the background of the 'Big Five Inventory'. Based on the five dimensions of a personality (openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism) a research model was designed. The research model divides the individual performance of professional purchasers into two major dimensions: operational and strategic. The operational dimension consists of the items 'cost', 'quality delivery' and 'flexibility'; the strategic dimension comprises the positions 'innovation', 'supplier satisfaction' as wells as 'purchasing and supply management integration in the organization'. To test the research model, a survey study was performed, and an online questionnaire was sent out to purchasing professionals in Austrian companies. The data collected from 78 responses was used to test the research model applying a group comparison. The comparison points out that there is (i) an influence of the purchasers’ personality on the individual performance of professional purchasers and (ii) a link between purchasers’ personality to a high or a low individual performance of professional purchasers. The findings of this study may help human resource managers during staff recruitment processes to identify the 'right performing personality' for an operational and/or a strategic position in purchasing departments.

Keywords: big five inventory, individual performance, personality, purchasing professionals

Procedia PDF Downloads 164

Authors: Gideon Yaniv, Erez Siniver, Yossef Tobol

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The extensive body of economic and psychological research correlating between students' cheating and their grade point average (GPA) consistently finds a significant negative relationship between cheating and the GPA. However, this literature is entirely based on students' responses to direct question surveys that inquire whether they have ever cheated on their academic assignments. The present paper reports the results of a two-round experiment designed to expose student cheating at the individual level and correlate it with their GPAs. The experiment involved two classes of third-year economics students incentivized by a competitive reward to answer a multiple-choice trivia quiz without consulting their electronic devices. While this forbiddance was deliberately overlooked in the first round, providing an opportunity to cheat, it was strictly enforced in the second, conducted two months later in the same classes with the same quiz. A comparison of subjects' performance in the two rounds, self-revealed a considerable extent of cheating in the first one. Regressing the individual cheating levels on subjects' gender and GPA exhibited no significant differences in cheating between males and females. However, cheating of both genders was found to significantly increase with their GPA, implying, in sharp contrast with the direct question surveys, that higher achievers are bigger cheaters. A second experiment, which allowed subjects to answer the quiz in the privacy of their own cars, reveals that when really feeling safe to cheat, many subjects would cheat maximally, challenging the literature's claim that people generally cheat modestly.

Keywords: academic achievement, cheating behavior, experimental data, grade-point average

Procedia PDF Downloads 199

Authors: Sunho Seo, Younghwan Shin, Jong-Hong Park, Sooeun Song, Junsung Kim, Jusik Yun, Yongkyun Kim, Jong-Moon Chung

Abstract:

In order to effectively cope with large and complex disasters, disaster response training is needed. Recently, disaster response training led by the ROK (Republic of Korea) government is being implemented through a 4 year R&D project, which has several similar functions as the HSEEP (Homeland Security Exercise and Evaluation Program) of the United States, but also has several different features as well. Due to the unpredictiveness and diversity of disasters, existing training methods have many limitations in providing experience in the efficient use of disaster incident response and recovery resources. Always, the challenge is to be as efficient and effective as possible using the limited human and material/physical resources available based on the given time and environmental circumstances. To enable repeated training under diverse scenarios, an AR (Augmented Reality) and VR (Virtual Reality) combined simulator is under development. Unlike existing disaster response training, simulator based training (that allows remote login simultaneous multi-user training) enables freedom from limitations in time and space constraints, and can be repeatedly trained with different combinations of functions and disaster situations. There are related systems such as ADMS (Advanced Disaster Management Simulator) developed by ETC simulation and HLS2 (Homeland Security Simulation System) developed by ELBIT system. However, the ROK government needs a simulator custom made to the country's environment and disaster types, and also combines the latest information and communication technologies, which include AR, VR, and MPEG-DASH (Moving Picture Experts Group - Dynamic Adaptive Streaming over HTTP) technology. In this paper, a new disaster response training simulator is proposed to overcome the limitation of existing training systems, and adapted to actual disaster situations in the ROK, where several technical features are described.

Keywords: augmented reality, emergency response training simulator, MPEG-DASH, virtual reality

Procedia PDF Downloads 293