Performance Improvement of Various Types of Induction-based Wind Farms Using Center-node Unified Power Flow Controller

Ahmed Rashad,Salah Kamel,Francisco Jurado,Karar Mahmoud 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6

In this paper, we propose the use of center-node unified power flow controller (C-UPFC) for improving the performance of different types of wind farms and mitigating their negative impacts on the grid. C-UPFC is considered one of the modernist members on Flexible AC Transmission System (FACTS). C-stocktickerUPFC has the ability to control several system parameters; the active and reactive power at both ends of the interconnected transmission line and the voltage at the midpoint. Three different induction-based wind farms are considered; 1) Squirrel Cage Induction Generator (SCIG), 2) Doubly Fed Induction Generator (DFIG), and 3) a combination of SCIG and DFIG turbines, i.e., Combined Wind Farm (CWF). C-stocktickerUPFC is comprehensively modelled for the first time in MATLAB Simulink, then the performance of the three wind farms is assessed with and without this device during three phase faults. Probabilistic voltage stability index (Probabilistic VSI) is used to measure the stability of the studied systems. In addition, the performance of three wind farms integrated with C-UPFC is compared with their performance when they integrated with Static synchronous compensators (STATCOM). The results show that C-UPFC has the ability to enhance the performance of wind farms during the three phase fault. C-UPFC is capable to remain the connection between SCIG wind farm and the interconnected grid during the fault. The voltage of CWF is greatly enhanced in the case of using C-UPFC. C-UPFC also improves the output powers of DFIG and CWF, especially after fault clearance.

Genetic diversity and yield performance among T. Aman rice (Oryza sativa L.) landraces in Barishal region of Bangladesh

Mia Shamim,Ahmed Nasar Uddin,Islam Mohammad Zahidul,Rashad Md. Mainul Islam,Islam Md. Monirul,Zaman A. K. M. Mostafa 한국작물학회 2022 Journal of crop science and biotechnology Vol.25 No.2

Understanding genetic diversity of rice helps to improve its yield. Although many landraces of rice are grown in the coastal area of Bangladesh, their diversity has not been studied. Here, we report a comparison of 163 landraces of T. Aman rice. Data on diferent agronomic characters were collected while analysis of variance (ANOVA), Pearson’s regression, principal component analysis (PCA) and cluster analysis were performed. In addition, yield of local landraces was compared to modern cultivars using meta-analysis. Our results showed that the yield of local rice of this study was higher than both HYV and local rice grown in the farmers’ feld. Furthermore, landraces with longer plant height and heavier grain provided signifcantly higher yield. According to PCA, the highest contributing variables were the number of tillers per hill and plant height. Canonical variate analysis revealed that plant height and grain length–breadth ratio were major contributors in creating divergence. In the generalized distance (D2 ) and cluster analysis, landraces were split into fve diverse clusters with many sub-clusters. Considering overall diversity pattern, it is evident that a good number of T. Aman rice landraces can be used in future improvement programs for assembling many benefcial traits and increasing yield of rice.

An investigation of the nuclear shielding effectiveness of some transparent glasses manufactured from natural quartz doped lead cations

Kassem, Said M.,Ahmed, G.S.M.,Rashad, A.M.,Salem, S.M.,Ebraheem, S.,Mostafa, A.G. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.6

The influence of lead cations on natural quartz (QZ) from Egypt as a glass shielding material for the composition with nominal formula (10Na₂O - (90 - x) QZ - xPbO (where x = 30, 35, 40, 45 and 50 mol %)) was examined. The studied samples are synthesized via the melt quenching method at 1050 ℃. The X-ray diffraction XRD patterns were confirmed the glass nature for studied samples. Moreover, the optical properties, and the transparency for all compositions were examined by UV-Vis spectroscopy. Also, the major elemental composition of the natural quartz were estimated via the X-ray fluorescence (XRF) technique. Further, the density and molar volume were determined. Furthermore, the nuclear shielding parameters such as, mass attenuation coefficient, effective atomic number, electronic density, the total atomic, and electronic cross sections as well as the mean free path, and the half value layer with different gamma ray energies (81 keV-1407 keV) were calculated. Besides, the results showed that the shielding behavior towards the gamma ray radiation for all glass samples was increased as the increment in PbO concentration in the glass system.

Antihyperglycemic Effect of Crude Extracts of Some Egyptian Plants and Algae

Sameh Fekry AbouZid,Osama Mohamed Ahmed,Rasha Rashad Ahmed,Ayman Mahmoud,Ehab Abdella,Mohamed Badr Ashour 한국식품영양과학회 2014 Journal of medicinal food Vol.17 No.3

Diabetes mellitus is a major global health problem. Various plant extracts have proven antidiabetic activity and are considered as promising substitution for antidiabetic drugs. The antihyperglycemic effect of 16 plants and 4 algae, commonly used in Egypt for the treatment of diabetes mellitus, was investigated. A diabetes model was induced by intraperitoneal injection of nicotinamide (120 mg/kg body weight [b.wt.]), then streptozotocin (200 mg/kg b.wt.) after 15 min. Hydroethanolic extracts (80%) of the plants and algae under investigation were prepared. The extracts were orally administered to nicotinamide-streptozotocin–induced diabetic mice by a gastric tube at doses 10 or 50 mg/kg b.wt. for 1 week. The antidiabetic activity was assessed by detection of serum glucose concentrations at the fasting state and after 2 h of oral glucose loading (4.2 mg/kg b.wt.). Extracts prepared from Cassia acutifolia, Fraxinus ornus, Salix aegyptiaca, Cichorium intybus, and Eucalyptus globulus showed the highest antihyperglycemic activity among the tested plants. Extracts prepared from Sonchus oleraceus, Bougainvillea spectabilis (leaves), Plantago psyllium (seeds), Morus nigra (leaves), and Serena repens (fruits) were found to have antihyperglycemic potentials. Extracts prepared from Caulerpa lentillifera and Spirulina versicolor showed the most potent antihyperglycemic activity among the tested algae. However, some of the tested plants have insulinotropic effects, all assessed algae have not. Identification of lead compounds from these plants and algae for novel antidiabetic drug development is recommended.

Cytotoxicity Assessment of Six Different Extracts of Abelia triflora leaves on A-549 Human Lung Adenocarcinoma Cells

Al-Taweel, Areej Mohammad,Perveen, Shagufta,Fawzy, Ghada Ahmed,Ibrahim, Taghreed Abdou,Khan, Afsar,Mehmood, Rashad Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.11

The present investigation was designed to assess the anticancer activity of six different leaf extracts (ethyl acetate, methanol, chloroform, petroleum ether, n-butanol, and water soluble) of Abelia triflora on A-549 human lung adenocarcinoma epithelial cells. A-549 cells were exposed to $10-1000{\mu}g/ml$ concentrations of the leaf extracts of A. triflorafor 24 h and then percentage cell viability was assessed by 3-(4,5-dimethylthiazol-2yl)-2,5-biphenyl tetrazolium bromide (MTT) assay. The results showed that leaf extracts of A. triflora significantly reduced the viability of A-549 cells in a concentration-dependent manner. Decrease was recorded as 31% with ethyl acetate, 36% with methanol, 46% with chloroform, 54% with petroleum ether, 62% with n-butanol, and 63% with water soluble extracts at $1000{\mu}g/ml$ each. Among the various plant extracts, ethyl acetate extract showed the highest decrease in the percentage cell viability, followed by methanol, chloroform, petroleum ether, n-butanol, and water soluble extracts. Our results demonstrated preliminary screening of anticancer activity of different soluble extracts of A. triflora extracts against A-549 cells, which can be further used for the development of a potential therapeutic anticancer agents.

Profile of Non-Communicable Disease Risk Factors Among Employees at a Saudi University

Amin, Tarek Tawfik,Al Sultan, Ali Ibrahim,Mostafa, Ola Abdelmoniem,Darwish, Amr Ahmed,Al-Naboli, Mohamed Rashad Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.18

Background: There is paucity of studies defining the prevalence of non-communicable disease (NCD) risk factors in Saudi Arabia despite the surging epidemic of obesity, change in dietary habits and sedentary lifestyle. Objectives: This cross-sectional study aimed to assess the prevalence of NCDs risk factors among employees at King Faisal University in Al Hassa, Saudi Arabia and to determine the possible correlates for clustering of NCDs risk factors among them. Materials and Methods: All employees were invited to participate; the World Health Organization STEPwise approach was used for data collection which consisted of a personal interview to collect socio-demographic characteristics, NCD history, tobacco use, vegetables and fruit consumption, and physical activity (PA), followed by anthropometric measurements namely weight, height and waist circumference and blood pressure measurements, subjects were finally subjected to biochemical tests with determination of fasting plasma glucose, serum triglycerides, cholesterol and high density lipoproteins. Results: Of the surveyed employees (n=691), daily current smokers accounted for 22.7%. 94.9%, 95.1% and 86% consumed < 5 servings per day of vegetables, fruits and both fruits and vegetables respectively, 73% were physically inactive, 64% were overweight or obese, 22.1% had hypertension, and 21.5% were diabetics. Elevated cholesterol levels were found in 36.6%, low high density lipoproteins in 36.8%, and elevated triglycerides in 36.1%. Only 3% had no NCD risk factors, and 57.6% had ${\geq}3$ factors. Multivariate logistic regression showed that gender (being male, adjusted odds ratio 'aOR'=1.51), aged ${\geq}50$ years (aOR=3.06), < college education (aOR=1.75), current smokers (aOR=2.37), being obese (aOR=6.96) and having a low PA level (aOR=4.59) were the significant positive predictors for clustering of NCD risk factors. Conclusions: Over fifty percent of the studied university's employees had multiple (${\geq}3$) NCD risk factors. Screening and health promotion initiatives should be launched at least targeting the modifiable factors to avert the excessive risk for cardiovascular disease, diabetes mellitus and several types of cancers.

Steel Reinforced Self-Compacting Concrete (SCC) Cantilever Beams: Bond Behaviour in Poor Condition Zones

Wael Mohamed Montaser,Ibrahim Galal Shaaban,Joseph P. Rizzuto,Amr Hussein Zaher,Ahmed Rashad,Shorouk Mohamed El Sadany 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.3

Previous investigations carried out on reinforced self-compacted concrete (SCC) beams have reported contradictory results on reinforcement bond behaviour occurring in the zones defined for good bond conditions according to Eurocode2. Cantilevered SCC beams’ critical upper tension reinforcement bond behaviour has previously had limited reporting. In this study, the bond behaviour in normally vibrated concrete (NVC) and self-compacted concrete (SCC) in poor conditions zones are compared and the differences are highlighted. The effect of four parameters, including (i) concrete type (SCC and NVC), (ii) characteristic strength of SCC, (iii) lap splice length, and (iv) depth of concrete cover for the reinforcement is investigated. It was found that for the studied beams, increasing splice length improved the energy absorption and changed the failure mode to a more ductile manner even at the poor bond conditions zones. The maximum measured steel strains in SCC beams in the lap splice zones, were higher than those for NVC specimens. The mean bond stress values, for SCC beams with 25–50% lap splice lengths, were higher than those of NVC beams, with the same lap splice lengths, by 16–13%, respectively. The results of the current study showed that the empirical equations from the literature overestimated the bond strength of the splice lap length for cantilever upper steel in SCC beams with long splices which agrees with the state of the art as these equations were developed originally for short anchorage lengths.

Realistic Evaluation of Reinforcement Bond Strength in Alkali-Activated Slag Concrete Exposed to Elevated Temperature

Ismail Amer,Mohamed Kohail,M. S. El-Feky,Ahmed Rashad,Mohamed A. Khalaf 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.5

Alkali-activated concrete (AAC) has attained great popularity since finding it as an alternative to Portland cement concrete due to its superior characteristics in terms of mechanical properties and durability, and its low negative environmental impact. This research investigated both experimentally and analytically the bond behavior between alkali-activated slag concrete (AASC) and steel rebars considering some important parameters (rebar diameter and development length-to-diameter ratio) before and after exposure to elevated temperature using beam-end bond testing technique. The obtained experimental results were compared with those obtained from applying the CEB-FIP model and the well-known available equations in the literature. A modified model was proposed for predicting the bond behavior of AASC. Results have showed that the CEB-FIP model provides more conservative values for bond strength compared to the experimentally obtained results which increases the safety level when estimating the bond strength for design purposes. The proposed modified model achieved a higher correlation with the experimental results than the CEB-FIP model at ambient temperature.