This study proposed Carbon fiber reinforced polymers (CFRP) as additional transverse reinforcement at the critical zones of concrete filled steel tubular (CFST). An experimental study consisted of five main sets of specimens representing the ends of columns, such as those merging in through beam-column connections, was conducted. Each main set of specimens investigated the behavior of the concrete core for a specific case of CFST or CFRP wrapped CFST (CFCFST), and each main set comprised three similar specimens to get more accurate results. All specimens were 160 mm external diameter and 320 mm height and had the same concrete grade. The thicknesses of the steel tubes used were 2 and 3mm. The numbers of (CFRP) layers used were one and two layers. The results showed that one and two CFRP outer layers added to CFST greatly improved the concrete compression. Response showed 29% and 54% increase in the concrete core compressive strength, respectively. The increase in the steel tube thickness from 2mm to 3 mm caused 20% increase in the concrete core compressive strength. A new analytical model with a sufficient accuracy was driven to predict the concrete core strength for both CFST and CFCFST cases.

This study proposed Carbon fiber reinforced polymers (CFRP) as additional transverse reinforcement at the critical zones of concrete filled steel tubular (CFST). An experimental study consisted of five main sets of specimens representing the ends of columns, such as those merging in through beam-column connections, was conducted. Each main set of specimens investigated the behavior of the concrete core for a specific case of CFST or CFRP wrapped CFST (CFCFST), and each main set comprised three similar specimens to get more accurate results. All specimens were 160 mm external diameter and 320 mm height and had the same concrete grade. The thicknesses of the steel tubes used were 2 and 3mm. The numbers of (CFRP) layers used were one and two layers. The results showed that one and two CFRP outer layers added to CFST greatly improved the concrete compression. Response showed 29% and 54% increase in the concrete core compressive strength, respectively. The increase in the steel tube thickness from 2mm to 3 mm caused 20% increase in the concrete core compressive strength. A new analytical model with a sufficient accuracy was driven to predict the concrete core strength for both CFST and CFCFST cases.

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Cooling of buildings is an essential target for engineers and builders in the hot arid climate of Egypt. New cooling system was integrated into a single room built in Assiut University (El-Gorib site) in Assiut, Egypt. A passive cooling technique was integrated inside a short wind tower made from expanded paper (wet pad) 0.1 m thick. A water tube was installed on the top of the expanded paper with small nozzles. The results show that outlet air temperature from the wind tower is 27.3°C. The calculated predicted mean vote (PMV) is within the recommended range (−0.5 PMV +0.5). This indicates that occupants remain satisfied with indoor thermal environment after using the passive cooling system and the difference is nearly 6–7 K between outdoor and indoor. The system achieves the acceptable airflow rate with an average of 450 ppm for CO2 concentration during daytime. The relative humidity did not exceed 57% most of the time. The maximum airspeed inside the solar chimney was 3.5 m/s under the effect of a high solar radiation of 890 W/m2 . The findings show that solar chimney with passive cooling tower design (SCPC) system achieves comfortable thermal conditions with a significant improvement in building energy conservation

The development of Maximum Power Point Tracking (MPPT) techniques is continuing in order to increase the generated energy from photovoltaic (PV) generators. A variety of MPPT techniques have been proposed and classified based on three main categories: offline, online and hybrid techniques. This paper presents a review of the most popular techniques for offline and online tracking of the Maximum Power Point (MPP), which are the Adaptive Neuro-Fuzzy Inference System (ANFIS) and Hill Climbing (HC) techniques, respectively. This is in addition to a review for all hybrid techniques reported in the literature demonstrating their main merits and shortcomings. Moreover, the present paper combines the ANFIS and HC as a hybrid technique for the first time. The proposed technique involves the features of the ANFIS and HC techniques and mitigates their shortcomings in order to increase the generated PV electrical energy. The proposed technique is a combination of two stages to assess the duty ratio (control signal) being applied to a boost converter for MPP tracking. The first stage includes a set point calculation loop to estimate the duty ratio. The second stage involves a fine tuning loop to determine the exact duty ratio corresponding to the MPP. This achieves maximum power transfer to the load even under nonuniform climatic conditions using a relatively simple control system. The proposed technique has been simulated in MATLAB/SIMULINK environment and compared with some other MPPT techniques (the Constant Voltage (CV), ANFIS, HC, Incremental Conductance (IncCond) techniques) for steady state and rapidly changing climatic conditions (Ropp and sine radiation tests) as well as load variations. The results reveal that the proposed hybrid MPPT technique outperforms other MPPT techniques in term of performances indicators, which include the tracking speed, tracking accuracy and energy gain factor.

The present paper studies thoroughly the performance of the classical perturb-and-observe (P&O) method under fast-changing solar irradiation, including increase or decrease of the irradiation level with small or large steps, when the initial operating point lies to the right or left of the MPP. In sixteen case studies of sudden variation of solar irradiation, the classical P&O method fails to track MPP properly in four cases. The classical P&O tracker does not work properly under a ramp change of irradiation level. A modified P&O-based-MPP tracking method is proposed and tested under step and ramp changes of irradiation irrespective of the value and direction of the perturbation in irradiation level and the location of the initial operating point. The proposed method succeeds in capturing the MPP under a ramp or slow change of irradiation level. The proposed method tracks correctly the MPP in the above-mentioned case studies and shows better performance in tracking speed, steady state efficiency, dynamic efficiency and tracking accuracy when compared with the classical P&O method and other modified methods reported in the literature.

The present paper studies thoroughly the performance of the classical perturb-and-observe (P&O) method under fast-changing solar irradiation, including increase or decrease of the irradiation level with small or large steps, when the initial operating point lies to the right or left of the MPP. In sixteen case studies of sudden variation of solar irradiation, the classical P&O method fails to track MPP properly in four cases. The classical P&O tracker does not work properly under a ramp change of irradiation level. A modified P&O-based-MPP tracking method is proposed and tested under step and ramp changes of irradiation irrespective of the value and direction of the perturbation in irradiation level and the location of the initial operating point. The proposed method succeeds in capturing the MPP under a ramp or slow change of irradiation level. The proposed method tracks correctly the MPP in the above-mentioned case studies and shows better performance in tracking speed, steady state efficiency, dynamic efficiency and tracking accuracy when compared with the classical P&O method and other modified methods reported in the literature.

The objective of the present work is to investigate the performance of an active suspension system of a typical passenger car through the application of three different control strategies under three different road irregularities. Tested control strategies are PID, LQR and FLC. Road irregularities considered are: a single rectangular pothole, a single cosine bump, and an ISO class-A random road disturbance. A 2-DOF quarter-vehicle model is used to simulate, evaluate and compare performance of these controllers against each other and against the original passive suspension system. Both tire gripping force and actuator force were normalized with respect to vehicle weight to recognize tire separation and enhance readability and interpretation of results. Simulation results showed that, active suspension systems are advantageous compared to passive ones. Active suspension implementing FLC control surpassed both PID and LQR controllers. Improvement of ride comfort was recognized by a reduction of sprung mass displacement and acceleration up to 23.8% and 52% respectively compared to the passive case. Improvement of load capacity is clear with a suspension travel reduction up to 61%. Moreover, vehicle stability was enhanced by increasing the tire separation margin up to 28 % of vehicle weight. An actuator force up to 39.5% of vehicle weight is required. All achieved by active suspension implementing FLC control.

The objective of the present work is to investigate the performance of an active suspension system of a typical passenger car through the application of three different control strategies under three different road irregularities. Tested control strategies are PID, LQR and FLC. Road irregularities considered are: a single rectangular pothole, a single cosine bump, and an ISO class-A random road disturbance. A 2-DOF quarter-vehicle model is used to simulate, evaluate and compare performance of these controllers against each other and against the original passive suspension system. Both tire gripping force and actuator force were normalized with respect to vehicle weight to recognize tire separation and enhance readability and interpretation of results. Simulation results showed that, active suspension systems are advantageous compared to passive ones. Active suspension implementing FLC control surpassed both PID and LQR controllers. Improvement of ride comfort was recognized by a reduction of sprung mass displacement and acceleration up to 23.8% and 52% respectively compared to the passive case. Improvement of load capacity is clear with a suspension travel reduction up to 61%. Moreover, vehicle stability was enhanced by increasing the tire separation margin up to 28 % of vehicle weight. An actuator force up to 39.5% of vehicle weight is required. All achieved by active suspension implementing FLC control.