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

Developed high gain microstrip antenna like microphone structure for 5G application

We present a new development of microstrip antenna structure combining a simple circular structure with a ring antenna structure as the parasitic element to improve the antenna gain and bandwidth for 5G mobile application. The proposed antenna was fed by a 50Ω microstrip feeding line due to its advantages in performance. The antenna was designed and simulated using a single substrate with double layered copper (top and bottom) with the radiating patch on the top layer and full ground on the bottom layer of the same substrate. Three antennas have been designed namely; design1, design2 and design3 to complete the research works.The antennas ware simulated and optimized at 18 GHz using Computer Simulation Technology (CST) with permittivity, r = 2.2 and thickness, h = 1.57mm on low-loss material Roger RT-Duroid 5880 substrate. The antennas ware reasonably well matched at their corresponding frequency of operations. The simulation and measurement results have shown that the antenna works well. The simulation results have shown that the three antennas works well at the selected frequency. The final simulated antenna for design1, design2 and design3 has been fabricated to measure the performance and also to validate the simulation result with the measurement result. The measurement data for antenna design1, design2 and design3 shows frequency shift of 3% from the simulation result. The final protype of design3 gives 6.6dB gain, -14.51dB return loss, 180MHz bandwidth, and antenna efficiency of 53.9%. All three antennas ware measured using Vector network analyzer (VNA) and Anechoic chamber

Spider Haiku

The utilization of lightweight oil palm shell to produce high strength lightweight sustainable material has led many researchers towards its commercialization as structural concrete. However, the low tensile strength of Oil Palm Shell Concrete (OPSC) has hindered its development. This study aims to enhance the mechanical properties and flexural behaviours of OPSC by the addition of steel fibres of up to 3% by volume, to produce oil palm shell fibre-reinforced concrete (OPSFRC). The experimental results showed that the steel fibres significantly enhanced the mechanical properties of OPSFRC. The highest compressive strength, splitting tensile and flexural strengths of 55, 11.0 and 18.5 MPa, respectively, were achieved in the OPSFRC mix reinforced with 3% steel fibres. In addition, the flexural beam testing on OPSFRC beams with 3% steel fibres showed that the steel fibre reinforcement up to 3% produced notable increments in the moment capacity and crack resistance of OPSFRC beams, but accompanied by reduction in the ductility

Estimation of Photovoltaic Module Parameters based on Total Error Minimization of I-V Characteristic

Mathematical Modelling of photovoltaic (PV) modules is important for simulation and performance analysis of PV system. Therefore, an accurate parameters estimation is necessary. Single-diode and two-diode model are widely used to model the PV system. However, it required to determine several parameters such as series and shunt resistances that not provided in datasheet.  The main goal of PV modelling technique is to obtain the accurate parameters to ensure the I-V characteristic is closed to the manufacturer datasheet. Previously, the maximum power error of calculated and datasheet value are considered as objective to be minimized for both models. This paper proposes the PV parameter estimation model based minimizing the total error of open circuit voltage (VOC), short circuit current (ISC) and maximum power (PMAX) where all these parameters are provided by the manufacturer. The performance of single-diode and two-diode models are tested on different type of PV modules using MATLAB. It found that the two-diode model obtained accurate parameters with smaller error compared to single-diode model. However, the simulation time is slightly higher than single-diode model due extra calculation required

The implementation of the internship as a coursework in teaching and learning vocational education

Internship is one of the common practices of higher education institutions in Malaysia for enhancing the learning experience and technical skills among their students. Students who follow the internship programme are found not only to be able to develop their professional attributes but also have the opportunity to acquire professional networks and career paths. Besides being a conventional approach that links students with real-world employment experience for a programme, internship can also be implemented for a specific course within a programme. The article discusses the implementation of an internship programme as a pedagogical approach in providing experiential learning for a specific course, i.e., Foundation and Concrete Work. This study involved 51 second-year students who were pursuing a degree in vocational education at the Universiti Teknologi Malaysia. Analysis on the impact of the internship experience indicates that the internship programme is an effective pedagogical approach for experiential learning for foundation and concrete work course

Structural performance of reinforced concrete beams repairing from spalling

The effectiveness of a repair work for the restoration of spalled reinforced concrete (r.c.) structures depends to a great extent, on their ability to restore the structural integrity of the r.c. element, to restore its serviceability and to protect the reinforcements from further deterioration. This paper presents results of a study concocted to investigate the structural performance of eight spalled r.c. beams repaired using two advanced repair materials in various zones for comparison purposes, namely a free flowing self compacting mortar (FFSCM) and a polymer Modified cementitious mortar (PMCM). The repair technique adopted was that for the repair of spalled concrete in which the bond between the concrete and steel was completely lost due to reinforcement corrosion or the effect of fire or impact. The beams used for the experiment were first cast, then hacked at various zones before they were repaired except for the control beam. The beam specimens were then loaded to failure under four point loadings. The structural response of each beam was evaluated in terms of first crack load, cracking behavior, crack pattern, deflection, variation of strains in the concrete and steel, collapse load and the modes of failure. The results of the test showed that, the repair materials applied on the various zones of the beams were able to restore more than 100 of the beams' capacity and that FFSCM gave a better overall performance

The effect of variation of molarity of alkali activator and fine aggregate content on the compressive strength of the fly ash: Palm oil fuel ash based geopolymer mortar

The effect of molarity of alkali activator, manufactured sand (M-sand), and quarry dust (QD) on the compressive strength of palm oil fuel ash (POFA) and fly ash (FA) based geopolymermortar was investigated and reported. The variable investigated includes the quantities of replacement levels of M-sand, QD, and conventional mining sand (N-sand) in two concentrated alkaline solutions; the contents of alkaline solution, water, POFA/FA ratio, and curing condition remained constant. The results show that an average of 76% of the 28-day compressive strength was found at the age of 3 days. The rate of strength development from 3 to 7 days was found between 12 and 16% and it was found much less beyond this period. The addition of 100% M-sand and QD shows insignificant strength reduction compared to mixtures with 100% N-sand. The particle angularity and texture of fine aggregates played a significant role in the strength development due to the filling and packing ability. The rough texture and surface of QD enables stronger bond between the paste and the fine aggregate.The concentration of alkaline solution increased the reaction rate and thus enhanced the development of early age strength. The use of M-sand and QD in the development of geopolymer concrete is recommended as the strength variation between these waste materials and conventional sand is not high.Iftekhair Ibnul Bashar, U. Johnson Alengaram, Mohd Zamin Jumaat, and Azizul Isla

Mechanics model for simulating RC hinges under reversed cyclic loading

Describing the moment rotation (M/θ) behavior of reinforced concrete (RC) hinges is essential in predicting the behavior of RC structures under severe loadings, such as under cyclic earthquake motions and blast loading. The behavior of RC hinges is defined by localized slip or partial interaction (PI) behaviors in both the tension and compression region. In the tension region, slip between the reinforcement and the concrete defines crack spacing, crack opening and closing, and tension stiffening. While in the compression region, slip along concrete to concrete interfaces defines the formation and failure of concrete softening wedges. Being strain-based, commonly-applied analysis techniques, such as the moment curvature approach, cannot directly simulate these PI behaviors because they are localized and displacement based. Therefore, strain-based approaches must resort to empirical factors to define behaviors, such as tension stiffening and concrete softening hinge lengths. In this paper, a displacement-based segmental moment rotation approach, which directly simulates the partial interaction behaviors in both compression and tension, is developed for predicting the M/θ response of an RC beam hinge under cyclic loading. Significantly, in order to develop the segmental approach, a partial interaction model to predict the tension stiffening load slip relationship between the reinforcement and the concrete is developed.Ahmad Azim Shukri, Phillip Visintin, Deric J. Oehlers and Mohd Zamin Jumaa

Medication risk communication with cancer patients in a Middle East cancer care setting

Purpose: Cancer treatments are frequently associated with adverse effects, but there may be a cultural reluctance by care providers to be forthcoming with patients regarding these risks for fear of promoting nonadherence. Conversely, research in a number of countries indicates high levels of patient desire for this information. We sought to explore cancer patient experiences, satisfaction, and preferences for medication risk communication in a Middle East care setting. Methods: We developed and administered a ten-item questionnaire (Arabic and English) to a convenience sample of consenting adult patients receiving treatment at the National Center for Cancer Care and Research in Qatar. Results: One hundred and forty-three patients were interviewed. Most (88%) stated that the level of side effect information they received was sufficient, with physicians (86%) followed by pharmacists (39%) as the preferred sources. The majority (97%) agreed that knowing about possible side effects would help them recognize and manage the reaction, and 92% agreed that it would help them understand how to minimize or prevent the risks. Eighteen percent indicated that this information would make them not want to take treatment. Two-thirds (65%) had previously experienced intolerance to their cancer treatment regimen. Conclusion: Most patients surveyed expressed preference for the details of possible side effects they may encounter in their treatment. However, one in five considered such information a factor for nonadherence, indicating the need for patient-specific approaches when communicating medication risks.Undergraduate Research Experience Program award (UREP 14-001-3-001) from the Qatar National Research Fund (a member of Qatar Foundation)