This paper presents a low power, low noise preamplifier stage with simple common mode desensitization circuit for dynamic comparators. The target application of the proposed circuit is analog to digital converter for biomedical applications. Adopting TSMC 0.18μm technology, the proposed circuit is designed to work in weak inversion using gm/ID design methodology. The simulation results show that the preamplifier stage consumes less than 32nW using power supply of 0.75V. The input referred noise is 17μV, DC gain of 43.15dB and unity gain frequency of 300 kHz

This paper presents an economical study of the effect of demand-side management (DSM) by implementing a PV system on bulk customers on all elements of the electricity sector including their impact on grid operations and planning in the Kingdom of Saudi Arabia. Demand Side Management is assumed to be applied in Riyadh, as a case study, using the concept of load shaving by photovoltaic system implementation for bulk customers as a segment to manage the demand during peak period. The Time of Use (ToU) tariff model is developed and incorporated in this study. Then an economical study is carried out to calculate the money-saving by Saudi Electricity Company as the impact of load shaving at peak period. Moreover, the paper considers the economic impact of the load reduction influences on the long-term forecast and hence the investment in the conventional generation power plants. Finally, the study determines how much is the saving of electricity bills for bulk customers due to PV implantation including the expected payback period to support the usefulness of adopting DSM for the electricity sector in KSA.

This paper presents low voltage low power a rail to rail common mode range clocked comparator. The target application of the proposed circuit is analog to digital converter for biomedical applications. The proposed comparator is composed of two stages which are pre-amplifiers and modified strong-Arm latch. The outputs of NMOS-input and PMOS-input pre-amplifiers are combined by the modified Strong-Arm latch producing rail to rail common mode range clocked comparator. Adopting TSMC 0.18μm technology, the preamplifier stages were designed to work in weak inversion using g m /I D design methodology. The simulation results show that the preamplifier stage consumes less than 0.275μW using power supply of 0.75V. The pre-amplifier DC gain of 43.15dB and unity gain frequency of 300 kHz

Hybrid micro-grid systems (HMGS) are small scale power system where the energy sources are installed to supply local customers. These systems may be considered as promising energy solution to meet the increased in energy demand and traditional sources depletion. Cost of electricity, system reliability, and environmental impacts of the system are three design criteria that must be considered in obtaining the accurate parameters of hybrid renewable energy system components. In this paper, hybrid micro-grid renewable energy system includes photovoltaic system, (PV) wind energy system, (WES) battery bank,(BB) and conventional diesel generator (DG) are proposed to meet the energy requirements in remote area, located in Red Sea called city of Bernice, Egypt, at 23
540 3100 N, 35
280 2100 E. Optimization of Cost of Electricity (COE), Renewable Factor (RF), and Loss of Power Supply Probability (LPSP) are main objective of the designing process of the hybrid system considered as the objective functions. Then, Multi-objective multi-verse optimization (MOMVO) algorithm is used with considering two scenarios, the first one is renewable sources and the second is renewable/diesel energy source. All the possible HMGS configurations namely: PV/battery, wind/battery, PV/wind/battery and PV/battery/diesel, wind/-battery/diesel, PV/wind/battery/diesel are studied and analyzed. Moreover, one year hourly meteorolog-ical weather data for case study are recorded. Reverse osmosis desalination (ROD) is considered in conjunction with the residential load. The proposed power management strategy is used to manage the system operation when supplying the load. A linear fuzzy membership function is used for purpose of decision making. The simulation results show that MOMVO produces appropriate components size and the PV/wind/battery/diesel is the optimum configuration with values of COE = 0.2720$/KWh, LPSP = 0.1397, and RF = 92.37% at w1 = 0.5, w2 = 0.3, and w3 = 0.2. Sensitivity analysis is performed to show the effect of changing system parameters on the objective functions. It is also shown that the techno-economic feasibility of using HMGS for rural electrification systems and enhance energy access.  2021 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Ain Shams Uni-versity. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Agricultural drainage water (ADW) reuse is the most promising option to increase the availability of water for irrigation. The pollution of drainage networks and the Nile River water supply shortage threaten the largest ADW reuse project in Egypt (El-Salam Canal), especially following the construction of the Grand Ethiopian Renaissance Dam (GERD). Accordingly, a one-dimensional hydrodynamic and water quality (WQ) simulation model was built as a tool to manage the quantity and quality of the canal water using MIKE 11 modules. Three proposed scenarios aimed to assess the current situation (Scenario 1), the best WQ parameter reduction ratio of the highly pollutant drains (Scenario 2), and the effect of the construction of the GERD on the canal WQ (Scenario 3). The results provided a quantitative canal WQ management tool to comply with the standards for irrigation purposes and illustrated that after the …

Introduction

Anterior distal femoral hemiepiphysiodesis using intra-articular plates for correction of pediatric fixed knee flexion deformities (FKFD) has two documented complications: postoperative knee pain and implant loosening. The aim of this study is to investigate the mechanical properties of a novel extra-articular technique for anterior distal femoral hemiepiphysiodesis in patients with FKFD and to compare them to the conventional technique.

Materials and methods

Sixteen femoral sawbones were osteotomized at the level of the distal femoral physis and fixed by rail frames to allow linear distraction simulating longitudinal growth. Each sawbone was tested twice: first using the conventional technique with eight plates placed anteriorly just medial and lateral to the femoral sulcus (group A) and then with plates inserted in the proposed novel location at the most anterior part of the medial and lateral surfaces of the femoral condyles with screws in the coronal plane (group B). Gradual linear distraction was performed, and the resulting angular correction was measured. Strain gauges were attached to the plates, and the amount of strain (and equivalent stress) over the plates in response to linear distraction was recorded. The two groups were compared using the Wilcoxon signed-rank test.

Results

The amount of angular correction was statistically higher in group B (extra-articular plates) at 5, 10-, and 15-mm of distraction (p < 0.001). As regards stress over the plates, the maximum stress and the area under the curve (sum of all stresses measured throughout the distraction process) were significantly higher when the plates were inserted at the conventional position (group A) (p < 0.001).

Conclusions

During anterior distal femoral hemiepiphysiodesis, the fixation of the eight plates in the coronal plane at the anterior part of the femoral condyles may produce a greater amount of correction and a lower degree of stress over the implants as compared to the conventional technique.

The overall compressive behaviour of grouted concrete hollow block prisms is dependent on the mechanical properties of both the masonry block and its grout. Grout is typically characterized by exhibiting greater longitudinal and lateral strains when compared to concrete blocks. Hence, a direct consequence is a composite-action incompatibility due to grout-to-block differential strain response under compressive loading. In order to enhance the overall composite behaviour, adding glass fibres to the grout mixture is considered in this study. The fibre-reinforced grout is expected to reduce grout longitudinal and lateral strains to be more consistent with the concrete block, which will result in better control of the cracking propagation and thus enhancing the overall ductility. This study investigates the effect of adding glass fibres to grout mix on the compressive strength and strain of the concrete masonry prisms. The presented experimental program involves testing of 36 fully grouted half-scale masonry prisms, with different glass fibre ratios (0%, 0.03%, 0.06%, and 0.10%). Twenty-four prisms were of one block thickness and two blocks in height, divided into two groups of normal and high strength blocks. The remaining twelve prisms were two blocks in thickness and five blocks in height with normal strength blocks. The prisms were tested concentrically up to failure. Results demonstrated that the addition of glass fibres to the grout enhanced the crack control as well as the post-cracking performance. The influence of adding glass fibres to the grout on increasing the masonry prisms' compressive strength was evident at high fibre percentage (i.e., 0.10%) by approximately 9.8%, 10.1 %, and 39% for the high strength two-block high specimens, normal strength two-block high specimens, and normal strength five-block high specimens, respectively.

Reinforced masonry (RM) shear walls with boundary elements (BE) have been recently presented as a ductile alternative to RM rectangular shear walls. The present study addresses the applicability of reinforcing masonry shear walls with glass fibre-reinforced polymer (GFRP) bars to attain reasonable strength and drift. GFRP-RM shear walls are a corrosion-free lateral resisting system that is transparent to magnetic fields and radio frequencies and nonconductive thermally and electrically. A numerical macro-model is developed using OpenSees to simulate the in-plane response of flexure-dominated reinforced masonry shear walls with boundary elements (RMSW-BE). The model was validated against experimentally tested walls from the literature. The boundary elements were designed with C-shaped masonry blocks. A numerical study is performed on thirty-four flexure-dominated shear walls to evaluate the influence of different design parameters on the inelastic behaviour of RMSW-BEs under quasi-static fully reversed cyclic loading. The investigated parameters are transverse hoop spacing, amount of vertical reinforcement in the boundary element, GFRP or steel reinforcement, and aspect ratio of the wall. In addition, walls with rectangular boundary elements were investigated to study the effect of increasing their size on the overall wall response. The influence of the design parameters on the hysteretic response, stiffness degradation, effective stiffness, and ductility related response modification factor was investigated to evaluate the enhancement in the seismic performance of RM buildings with RMSW-BE.

Recent advances in reinforcing lateral-load resisting systems with glass-fiber-reinforced-polymer (GFRP) bars have highlighted the need for farther experimental investigations. With the elastic behavior of GFRP-bars, ensuring sufficient plastic deformations become challenging. The current study presents the experimental work performed on six full-scale GFRP-reinforced concrete shear walls with boundary elements. The mid-rise building shear walls were tested under reversed quasi-static cyclic loading, with an emphasis on how varying the configuration of the boundary-element confinement would influence their strength and deformation performance. Two shear walls had boundaries reinforced with square GFRP spiral stirrups, while a third had boundaries reinforced with circular GFRP spiral stirrups. The remaining three shear walls had higher confinement in the boundary elements; one had a square GFRP spiral stirrups embedded inside rectangular GFRP spiral stirrups. The second had a rectangular GFRP spiral stirrups with two GFRP ties in the middle, and the third had two square spiral stirrups overlapped side-by-side. The overall performance of each specimen was characterized by investigating the hysteretic response, the cracking patterns, the drift ratio, the strength capacity, and the behavior of energy dissipation. Also, the strain progressing in the longitudinal, horizontal, stirrups, and concrete was investigated. The obtained results demonstrate that increasing the confinement level in the boundary elements enhanced deformation capacity and increased the overall strength of the GFRP-reinforced shear walls by developing a higher level of concrete compressive strains and a better distribution of shear deformations over the height.

The design of lateral-resisting reinforced-concrete elements requires prediction of the fundamental period and drift, which are determined using linear elastic dynamic analysis. To estimate the linear elastic response, the cross section of the structural element is assumed to have a linear flexural stiffness that accounts for cracking. This emphasizes the need for a reliable model for the effective stiffness in both flexure and shear response. In this study, six reinforced concrete (RC) shear walls reinforced entirely with glass fiber-reinforced polymers (GFRPs) reinforced bars were tested under reversed cyclic loading. The wall portion of all the specimens had the same dimensions: 3500 mm (137.8 in.) in height, 1500 mm (59.1 in.) in length, and 200 mm (7.87 in.) in width. The test specimens were subjected to a constant axial load of 0.15fc′Ag and a displacement-controlled lateral-loading history. The experimental results were presented and discussed to introduce the effective stiffness relationship based on cracking, failure progression, deformation, and strength degradation. The deformability factor was estimated using the serviceability and ultimate limit states based on the allowable deformation limits. A simple trilinear moment-curvature model was developed to predict the flexural response of the tested walls. A simple procedure is proposed and recommended to predict the lateral displacement of the GFRP-reinforced shear walls.