Electro-absorption of silicene and bilayer graphene quantum dots

We study numerically the optical properties of low-buckled silicene and AB-stacked bilayer graphene quantum dots subjected to an external electric field, which is normal to their surface. Within the tight-binding model, the optical absorption is calculated for quantum dots, of triangular and hexagonal shapes, with zigzag and armchair edge terminations. We show that in triangular silicene clusters with zigzag edges a rich and widely tunable infrared absorption peak structure originates from transitions involving zero energy states. The edge of absorption in silicene quantum dots undergoes red shift in the external electric field for triangular clusters, whereas blue shift takes place for hexagonal ones. In small clusters of bilayer graphene with zigzag edges the edge of absorption undergoes blue/red shift for triangular/hexagonal geometry. In armchair clusters of silicene blue shift of the absorption edge takes place for both cluster shapes, while red shift is inherent for both shapes of the bilayer graphene quantum dots.Comment: 7 pages, 7 figure

A probabilistic multi-objective approach for FACTS devices allocation with different levels of wind penetration under uncertainties and load correlation

This study presents a probabilistic multi-objective optimization approach to obtain the optimal locations and sizes of static var compensator (SVC) and thyristor-controlled series capacitor (TCSC) in a power transmission network with large level of wind generation. In this study, the uncertainties of the wind power generation and correlated load demand are considered. The uncertainties are modeled in this work using the points estimation method (PEM). The optimization problem is solved using the Multi-objective particle swarm optimization (MOPSO) algorithm to find the best position and rating of the flexible AC transmission system (FACTS) devices. The objective of the problem is to maximize the system loadability while minimizing the power losses and FACTS devices installation cost. Additionally, a technique based on fuzzy decision-making approach is employed to extract one of the Pareto optimal solutions as the best compromise one. The proposed approach is applied on the modified IEEE 30-bus system. The numerical results evince the effectiveness of the proposed approach and shows the economic benefits that can be achieved when considering the FACTS controller

FACTS allocation considering loads uncertainty, steady state operation constraints, and dynamic operation constraints

This study proposes an algorithm to allocate different types of flexible AC transmission system (FACTS) in power systems. The main objective of this study is to maximize profit by minimizing the system’s operating cost including FACTS devices (FDs) installation cost. Dynamic and steady state operating restrictions with loads uncertainty are included in the problem formulation. The overall problem is solved using both teaching learning based optimization (TLBO) technique for attaining the optimal allocation of the FDs as main-optimization problem and matpower interior point solver (MIPS) for optimal power flow (OPF) as the sub-optimization problem. The validation of the proposed approach is verified by applying it to test system of 59-bus; Simplified 14-Generator model of the South East Australian power system

Population based optimization algorithms improvement using the predictive particles

A new efficient improvement, called Predictive Particle Modification (PPM), is proposed in this paper. This modification makes the particle look to the near area before moving toward the best solution of the group. This modification can be applied to any population algorithm. The basic philosophy of PPM is explained in detail. To evaluate the performance of PPM, it is applied to Particle Swarm Optimization (PSO) algorithm and Teaching Learning Based Optimization (TLBO) algorithm then tested using 23 standard benchmark functions. The effectiveness of these modifications are compared with the other unmodified population optimization algorithms based on the best solution, average solution, and convergence rate

Generalized optimal placement of PMUs considering power system observability, communication infrastructure, and quality of service requirements

This paper presents a generalized optimal placement of Phasor Measurement Units (PMUs) considering power system observability, reliability, Communication Infrastructure (CI), and latency time associated with this CI. Moreover, the economic study for additional new data transmission paths is considered as well as the availability of predefined locations of some PMUs and the preexisting communication devices (CDs) in some buses. Two cases for the location of the Control Center Base Station (CCBS) are considered; predefined case and free selected case. The PMUs placement and their required communication network topology and channel capacity are co-optimized simultaneously. In this study, two different approaches are applied to optimize the objective function; the first approach is combined from Binary Particle Swarm Optimization-Gravitational Search Algorithm (BPSOGSA) and the Minimum Spanning Tree (MST) algorithm, while the second approach is based only on BPSOGSA. The feasibility of the proposed approaches are examined by applying it to IEEE 14-bus and IEEE 118-bus systems

PREVALENCE OF CONSANGUINEOUS MARRIAGES IN SOUTH SINAI, EGYPT

A total of 3961 married couples from six major geographical areas representing the South Sinai governorates in Egypt were studied to assess the rate of consanguineous marriage. The population of six selected areas (St Catherines, Nuweiba, Abu Rudeis, Ras Sudr, El Tor and Abu Zenima) were subdivided into Bedouin, urban and mixed populations. A questionnaire-based interview was conducted showing that the consanguinity rate in this region is 37.5%, with the highest rate recorded in Abu Rudeis (52.3%) and lowest rate in Nuweiba (24.1%). Consanguinity was significantly higher among the Bedouin population compared with the urban population in Abu Rudeis, Ras Sudr, El Tor and Abu Zenima, while in St Catherines and Nuweiba there was no statistically significant difference. Among consanguineous couples, 5%, 60% and 35% were double first cousins, first cousins and second cousins respectively. The mean inbreeding coefficient α of the studied population was 0.0184

Anthracnose Disease (Colletotrichum sp.) Affecting Olive Fruit Quality and Its Control in Egypt

Abstract Olive anthracnose is the most important fungal disease of olive fruits worldwide. It occurs in humid olive-growing areas of many countries and causes heavy yield losses and lowering of oil quality. Colletotrichum acutatum was isolated and identified from rotten olive fruits. Pathogenicity test of C. acutatum was confirmed. It was found to be decreased all physical characteristics measured i.e. weight (gm), length (mm), diameter (mm) and volume (ml3). Also, C. acutatum was found to decrease the oil content of the fruits, while increasing their total titratable acidity and moisture content. Physiological studies resulted that, the highest growth rate and sporulation was recorded with PDA medium, PH 6.5 and Light/dark cycle treatments. Hot water treatments at 45, 50 and 55°C were able to decreased spore viability of C. acutatum compared with untreated (control). The best treatment of hot water was recorded with 55°C. in vivo. Also, hot water treatment at 55°C was successful in reducing the percentage of anthracnose disease incidence on olive fruits in vitro. All tested alternative substrates i. e. Ascorbic acid, Benzoic acid, potassium sorbate and citric acid used were able to reduce the linear growth rate of C. acutatum in vitro. Benzoic acid was found to be the best alternative substrate used which gave completely fruit protection (hundred of reduction percent) followed by Ascorbic acid, Potassium sorbate and Citric acid. This is thought to be the first report of anthracnose disease of olive fruits in Egypt

Serum leptin level and microvascular complications in type 2 diabetes

Background. Type 2 diabetes (T2DM) and its complications are highly prevalent in Egypt and are considered a major health problem. Insulin resistance arising from visceral obesity is the main pathological mechanism of T2DM. Leptin is an adipokine secreted from visceral adipose tissue and its level is proved to be higher in patients with T2DM, but its association with microvascular complications is not yet well-established, for this aim the present study was conducted. Methods. This cross-sectional study was conducted among 120 participants with T2DM recruited from the diabetes outpatient clinic of Alexandria Main Uni­versity Hospital, Alexandria, Egypt. Each participant was subjected to full history taking, complete physical examination and laboratory investigations. Results. Serum leptin level was significantly positively correlated with diabetes duration, BMI, WC, systolic and diastolic blood pressure, FPG, HbA1c, serum insu­lin level, HOMA-IR, total cholesterol, triglycerides and LDL-C. Regarding microvascular complications, serum leptin level was highly significantly positively correlated with UACR, peripheral neuropathy and retinopathy (P < 0.001) and significantly negatively correlated with e-GFR (P = 0.003). Conclusions. Serum leptin level is significantly correlated with microvascular complications in patients with T2DM in Alexandria, Egypt