Load-deflection Analysis of CFRP Strengthened RC Slab Using Focused Feed-forward Time Delay Neural Network

In this paper, the load-deflection analysis of the Carbon Fiber Reinforced Polymer (CFRP) strengthened Reinforced Concrete (RC) slab using Focused Feed-forward Time Delay Neural Network (FFTDNN) is investigated. Six reinforced concrete slabs having dimension 1800×400×120 mm with similar steel bar of 2T10 and strengthened using different length and width of CFRP were tested and compared with similar samples without CFRP. The experimental load-deflection results were uploaded, normalized, and converted to a time sequence parameter in MATLAB software. Loading, time, and the effect of the different CFRP strip lengths on the slab moment of inertia were as neurons in input layer and mid-span deflection was as neuron in output layer. The network was generated using feed-forward network and a tapped delay line at the input layer to memorize the input data while training process. From 122 load-deflection data, 111 data utilized for network generation and 11 data for the network testing. The results of model on the testing stage showed that the generated FFTDNN predicted the load-deflection analysis of the slabs in acceptable technique with a correlation of determination of 0.98. The ratio between predicted deflection by FFTDNN and experimental output was in the range of 0.92 to 1.23

Depicting students social presence on social networking site in course-related interaction

Social networking sites (SNS) are widely used among students, where its integration in higher education is increasing across years. Therefore, this study aimed to analyze students’ use of social presence (SP) expressions in blended learning environment using Facebook group as a medium of online discussion. A total of 11 students and one instructor were involved in 7-week multimedia learning course in one of the Malaysian universities. The content of students’ online discussion on Facebook group was the source of the data in this study. The discussion content was transcribed, coded, and analyzed, and the frequencies of categories were calculated to determine students’ use of SP expressions. The findings of the study revealed that students focus on delivering more interactive response (IR) posts across all learning topics. Interestingly, although SNS are social in nature, this study revealed that students’ use of SP expressions on SNS was intended to improve course discussion interactivity rather than for pure socializing purpose. However, more theoretical topics triggered higher number of SP posts compared with technical focused topics. More importantly, the way students used SP expressions during course-related interaction through Facebook may contribute to improved performance in test

Technical and implementation issues in reading literacy interactive games

The technology-based learning process is able to influence pupils on learning and teaching, especially the use of interactive games can transform the way learning of problematic learners in reading skills. Although interactive games are said to be very effective in learning but there are still many technical and implementation shortcomings on remedial education students which identified as slow learners. This paper focuses on technical and implementation issues which restrict the effective integration of Reading Literacy Interactive Games (RLIG) in learning of reading skill among slow learners. The aim of this study is to investigate the critical issues and develop the effective RLIG in order to fulfill the slow learners’ needs. Therefore, a need-analysis was conducted to investigate the issues of technical and implementation of RLIG among slow learners. The findings revealed that there are many technical and implementation issues that restricted slow learners from adapting RLIG in the process of teaching and learning. The findings of this research can assist educators to improve the development of RLIG by incorporating relevant pedagogical approaches and game-based features in the development process

Geometric effects of sustainable auxetic structures integrating the particle swarm optimization and finite element method

The development of new materials based on industrial wastes has been the focus of much research for a sustainable world. The growing demand for tyres has been every year exacerbating environmental problems due to indiscriminate disposal in the nature, making a potentially harmful waste to public health. The incorporation of rubber particles from scrap tyres into polymeric composites has achieved high toughness and moderate mechanical properties. This work investigates the geometric effects (thickness, width and internal cell angle) of auxetic structures made of recycled rubber composites based on experimental and numerical data. The response surface models integrated with the swarm intelligence and finite element analysis were proposed in order to obtain a range of solutions that provides useful information to the user during the selection of geometric parameters for reentrant cells. The results revealed the cell thickness ranges from 39-40 mm and 5.98-6 mm, and the cell angle range from -0.01 to -0.06º maximize the ultimate strength. The same parameters were able to optimize the modulus of elasticity of rubber auxetic structures, excepting for the angle factor which must be set between -30º and 27.7º. The optimal Poisson's ratio was found when the cell angle ranged from -30º to -28.5º, cell width ranged from 5-5.6 mm and 2 mm in thickness

Behaviour of precracked RC beams strengthened using the side-NSM technique

The side near-surface mounted (SNSM) method is an alternative method used for applying fibre reinforced polymer (FRP) flexural strengthening on reinforced concrete (RC) beams. The SNSM method places the FRP grooves at the sides of the beam, rather than at the bottom in the normal near surface mounted (NSM) method. This research focuses on studying the performance of precracked RC beams when strengthened with the SNSM method. Six RC beams strengthened with the side-NSM (SNSM) method were tested in flexure. Precracked SNSM strengthened beams have reduced ultimate load by up to 3.3% and higher stiffness by up to 28.4% compared to non-precracked SNSM strengthened beams. The modes of failure for SNSM strengthened beams was identical for the precracked beams and the equivalent non-precracked beams. A simulation method based on the moment-rotation approach was also presented and was found to be reasonably accurate and able to simulate the change in stiffness caused by precracking

Project-based learning from constructivism point of view

Constructivism is a learning theory that perceives learning as a process of constructing knowledge based from experience. Issues of difficulty in translating this learning theory into a teaching and learning practice have become a debate among educational researchers. One of the learning approaches that reflect the theory of constructivism is project-based learning or PjBL. Terms such as “authentic learning activity” and “hands-on learning” is commonly represented as constructivist which believes and addressed learning through rigorous, relevant and hands-on practice. This study will explore the notion of constructivism as a learning theory in connection with PjBL and investigate the integration of constructivism in PjBL setting. The implications of constructivism in the PjBL setting will also be discussed

Статистика : учебное пособие : [для студентов 2-го курса ФП по специальности "Организация работы с молодежью"]

Steel pallet rack (SPR) beam-to-column connections (BCCs) are largely responsible to avoid the sway failure of frames in the down-aisle direction. The overall geometry of beam end connectors commercially used in SPR BCCs is different and does not allow a generalized analytic approach for all types of beam end connectors; however, identifying the effects of the configuration, profile and sizes of the connection components could be the suitable approach for the practical design engineers in order to predict the generalized behavior of any SPR BCC. This paper describes the experimental behavior of SPR BCCs tested using a double cantilever test set-up. Eight sets of specimens were identified based on the variation in column thickness, beam depth and number of tabs in the beam end connector in order to investigate the most influential factors affecting the connection performance. Four tests were repeatedly performed for each set to bring uniformity to the results taking the total number of tests to thirty-two. The moment-rotation (M-θ) behavior, load-strain relationship, major failure modes and the influence of selected parameters on connection performance were investigated. A comparative study to calculate the connection stiffness was carried out using the initial stiffness method, the slope to half-ultimate moment method and the equal area method. In order to find out the more appropriate method, the mean stiffness of all the tested connections and the variance in values of mean stiffness according to all three methods were calculated. The calculation of connection stiffness by means of the initial stiffness method is considered to overestimate the values when compared to the other two methods. The equal area method provided more consistent values of stiffness and lowest variance in the data set as compared to the other two methods.</p

Behavior of Industrial Steel Rack Connections

Beam-to-column connections (BCCs) used in steel pallet racks (SPRs) play a significant role to maintain the stability of rack structures in the down-aisle direction. The variety in the geometry of commercially available beam end connectors hampers the development of a generalized analytic design approach for SPR BCCs. The experimental prediction of flexibility in SPR BCCs is prohibitively expensive and difficult for all types of commercially available beam end connectors. A suitable solution to derive a particular uniform M-θ relationship for each connection type in terms of geometric parameters may be achieved through finite element (FE) modeling. This study first presents a comprehensive description of the experimental investigations that were performed and used as the calibration bases for the numerical study that constituted its main contribution. A three dimensioned (3D) non-linear finite element (FE) model was developed and calibrated against the experimental results. The FE model took into account material nonlinearities, geometrical properties and large displacements. Comparisons between numerical and experimental data for observed failure modes and M-θ relationship showed close agreement. The validated FE model was further extended to perform parametric analysis to identify the effects of various parameters which may affect the overall performance of the connection.</p