Smart integration of a DC microgrid: Enhancing the power quality management of the neighborhood low-voltage distribution network

The fast development of the residential sector regarding the additional integration of renewable distributed energy sources and the modern expansion usage of essential DC electrical equipment may cause severe power quality problems. For example, the integration of rooftop photovoltaic (PV) may cause unbalance, and voltage fluctuation, which can add constraints for further PV integrations to the network, and the deployment of DC native loads with their nonlinear behavior adds harmonics to the network. This paper demonstrates the smart integration of a DC microgrid to the neighborhood low-voltage distribution network (NLVDN). The DC microgrid is connected to the NLVDN through a three-phase voltage source inverter (VSI), in which the VSI works as a distribution static compensator (DSTATCOM). Unlike previous STATCOM work in the literature, the proposed controller of the VSI of the DC smart building allows for many functions: (a) it enables bidirectional active/reactive power flow between the DC building and the AC grid at point of common coupling (PCC); (b) it compensates for the legacy unbalance in the distribution network, providing harmonics elimination and power factor correction capability at PCC; and (c) it provides voltage support at PCC. The proposed controller was validated by Matlab/Simulink and by experimental implementation at the lab

Developing a Performance Criteria for Stone Columns to Improve Surface Pavement for Weak Subgrade Conditions

AbstractSoft, saturated, fine grained subgrade soils are distinguished by their low undrianed shear strength and high compressibility. Such soils cover most of the middle and southern parts of Iraq. The effect of using stone column, encased in geogrid and steel mesh to improve pavement's performance is experimentally investigated and evaluated. To compare the experimental and analytical outputs, three dimensions finite element throughout elastic and elasto-plastic models using ABAQUS ver.6.12.3 software are developed to simulate and analyze the relations between the cycling load and deformation of the suggested pavement modes. Based on the results and the limitation of this study it is concluded that, using encased stone columns, is more practical and suitable alternative to improve weak subgrade against permanent deformation as compared with the other simulated pavement modes. The results of ABAQUS program are very close to results of laboratory tests

Molecular detection of Human Papillomavirus genotype-16&-18 in tissues from patients with prostate cancer and benign prostatic hyperplasia

Background: High oncogenic-risk genotypes of human Papillomavirus (HPV) infect a wide range of human cells, including prostate tissue that give rise to benign prostatic hyperplasia and prostatic adenocarcinomas. Objectives: This study aimed to detect DNA of HPV genotype-16 &18 using in situ hybridization technique in prostatic tissues from benign prostatic hyperplasia and prostatic adenocarcinomas, and elucidate the association between these HPV genotypes and prostatic carcinogenesis. Patients and methods: Forty-eight (48) formalin-fixed, paraffin embedded prostatic tissue blocks were obtained ,among them (28) tissue biopsies from prostatic carcinoma with different grades and (20) benign prostate hyperplastic tissue blocks as well as (10) apparently normal prostate tissue autopsies which were collected from the archives of Forensic Medicine Institute / Baghdad and used as prostate healthy control groups. Detection and genotyping of HPV was done by highly sensitive in situ hybridization technique. Results: The signals of in situ hybridization reactions of both HPV-16 and HPV-18 in prostate cancer cases in the present study was 25% (7 / 28) whereas in BPH, HPV-16 was detected in 45 %( 9 /20) and HPV-18 was presented in 35 %( 7/ 20). Neither HPV-16 nor HPV-18 was detected in the apparently healthy control group.The percentages of HPV 16 and HPV18 were increasing with advancing of grade of prostate cancer. Conclusion: Our results indicate that the oncogenic HPV-16 might contribute to the development of subset of prostate tumors. In addition, HPV16&18 might have a crucial role in progression of the prostate cancer and benign prostatic hyperplasi

Radiologic Management of Vascular Malformations’ Interventional, Classification and Diagnosis

This study aimed at analyzing the diverse group of congenital vascular malformations, with respect to their place within the broader classification of vascular anomalies and their pathologic, clinical, and radiologic diagnosis and management. And the study discuss some of the techniques, agents, and approaches used in the interventional treatment of this difficult group of lesions. The researchers are aware and acknowledge that there are several different techniques and agents that can be used to treat these lesions. The techniques and agents described in this article have been used for years by the experts with good results. The aim of this study is to share experience in the management of vascular malformations with these techniques at Jordanian hospitals, and to assess the patient satisfaction levels by the evaluation of the follow-up of patients with vascular malformations treated in the Interventional Radiology Unit from January 2016 to December 2016. Patients were classified according to the hemodynamics of the lesions (high- vs. low-flow)

The Prospect of Waqf in Financing Small and Medium Enterprises (SMEs) in Yemen

The role of small and medium enterprises (SMEs) in economic development has been duly recognised. However, SMEs encounter a number of challenges. The most pressing obstacle SMEs face is the lack of finance. Therefore, it is extremely important to find new and suitable finance sources in order to support SMEs either in their establishment or growth phases. Waqf is regarded one of the best sources of finance in the Islamic financial system. There is much potential in its use to finance SMEs financing. The present study explored the prospect of Waqf as an Islamic financial instrument to finance SMEs. It further examined a proposed modified Waqf model and whether it was applicable in Yemen. The study has adopted a qualitative method in the form of semi-structured interviews with 6 experts from Waqf institutions and from SMEs developmental institutions. The experts interviewed are mainly SMEs owners, Waqf directors and beneficiaries specialized in the areas of Waqf and SMEs. The findings of the study indicate that Waqf appeared to be one of the most important instruments in financing such economic activities as it can play a crucial role in financing SMEs. Further, the study significantly contributed by suggesting a new method that will help in financing small and medium enterprises (SMEs) in Yemen. Thus, providing a finance for these firms will help to create more jobs for the low income, which in turn helps in the economic development

Dynamic Analysis of Foundations on Saturated Clay Using an Energy Absorbing Layer

In this study, a method to model the semi-infinite extension (unbounded domain) of the saturated soil is developed. In this method, the unbounded domain is replaced by an absorbing layer of finite thickness with properties that appreciably reduce the wave reflection into bounded domain. In this layer, the soil is represented by the same properties as in the soil close to the foundation (bounded domain) and a model of frequency-dependent damping is implemented. A three-dimensional dynamic analysis of rectangular footing on a saturated soil is carried out. The foundation is subjected to four cycles of harmonic force. The coupled dynamic equations with u-p formulation based on the dynamic consolidation theory are used to simulate the soil skeleton and pore fluid responses. The solid particles of the soil are represented by linear elastic behavior. It was found that a decay in wave can be noticed when the unbounded domain of the saturated soil is represented by the energy absorbing layer. In addition, the maximum displacement of the foundation will be decreased due to using the energy absorbing layer in comparison with the elementary boundaries. The excess pore water pressure that developed during the dynamic loading will be dissipated with time in a fast rate due to using the energy absorbing layer

European Vitreoretinal Society Macular Hole Study, Prognostic Factors for Anatomical and Functional Success

Background: To identify prognostic preoperative and intraoperative factors for anatomical and visual success of idiopathic macular hole (MH) surgery. Methods: We conducted a non-randomized, collaborative multicenter study using data of 4207 MH surgery from 140 surgeons. Main study outcomes were anatomical closure and best corrected visual acuity (BCVA) improvement postoperative at 6-12 months. Results: Information on anatomical success was available for 4138 eyes of 4207 operations. Anatomical closure of MH was achieved in 85.7% (3546 eyes). Closure was higher in smaller MH (stages 1-2 versus stage 3: OR=0.35; stage 2 versus stage 4: OR=0.16, and in MH with shorter duration before the operation (OR=0.94). Macular Holes were more likely to close when dyes were used to facilitate internal limiting membrane (ILM) peeling (odds ratio=1.73 to 3.58). The most important predictors of postoperative BCVA were the preoperative BCVA (estimate=0.39, p<0.001) and closure of the macular hole (estimate=0.34, p<0.001). We observed Larger improvement in BCVA in combined vitrectomy and phacoemulsification (estimate = 0.10) and post cataract surgery in phakic eyes (estimate=0.05). Retinal tears occurred in 5.1% of eyes, and were less with use of trocars (OR= -1.246) and in combined vitrectomy/ phacoemulsification surgery (OR= -0.688). Conclusion: This international survey confirmed that staining with dyes improves anatomical results but not visual outcomes. After surgery, visual acuity improved during the first year, and final visual acuity was better in both pseudophakic eyes and eyes that underwent cataract surgery during the first year following MH repair

Fabrication and Characterization of Nickel Chloride Doped PMMA Films

Films of PMMA and PMMA doped with NiCl2 with different contents were prepared using the casting technique. The optical properties of all films were investigated using spectrophotometric measurements of absorbance and transmittance in the wavelength range 200–800 nm. The change of the calculated values of the optical energy gaps with increasing NiCl2 content has been interpreted in terms of the structural modifications of the PMMA matrix. The optical energy gap decreased from 3.6 to 3.05 eV with increasing the NiCl2 concentration to 0.4%. The effect of doping on the optical constants of films such as refractive index, extinction coefficient, real and imaginary parts of dielectric constant, optical conductivity, and skin depth has been reported. All these constants were increased with increasing NiCl2 concentration with the exception of skin depth which is different result

Association of the serum chemerin level with the development of diabetic retinopathy in patients with type 1 diabetes mellitus

Background: In patients with type 2 diabetes mellitus, the development of diabetic retinopathy (DR) correlates positively with elevated serum chemerin levels. This study was aimed at investigating the probable association between the serum chemerin level and the development of DR in patients with type 1 diabetes mellitus (T1DM). Methods: In this cross-sectional study, we included Egyptians and classified them into four groups: group 1, including healthy individuals; group 2, including patients with T1DM without DR; group 3, including patients with T1DM with non-proliferative DR (NPDR); and group 4, including patients with T1DM with proliferative DR (PDR). The assessment included best-corrected distance visual acuity assessment, slit-lamp biomicroscopy, funduscopy, fundus fluorescein angiography, and macular ocular coherence tomography. Fasting blood samples were obtained from all participants to measure serum chemerin, glycated hemoglobin (HbA1c), total cholesterol, triglyceride, and creatinine levels. Serum chemerin levels were compared among the groups, and their correlations with age, duration of diabetes, HbA1c, total cholesterol, triglyceride, and creatinine levels were analyzed. Results: We recruited 209 participants, including 46 healthy individuals in group 1, 52 patients (T1DM and no DR) in group 2, 61 patients (T1DM and NPDR) in group 3, and 50 patients (T1DM and PDR) in group 4, with comparable mean ages and sex ratios among groups. The diabetes duration, body mass index, HbA1c, total cholesterol, triglyceride, and serum chemerin levels differed significantly among the groups (all P < 0.001), whereas the creatinine level did not (P > 0.05). The serum chemerin level was significantly higher in group 4 than in groups 3 and 2, in group 3 than in group 2, and in groups 3 and 4 than in group 1 (all P < 0.001). However, it was comparable between groups 1 and 2 (P > 0.05). It correlated with the duration of T1DM and HbA1c, total cholesterol, triglyceride, and creatinine levels but not with age. Conclusions: Patients with T1DM with DR showed higher serum chemerin levels than those with T1DM without DR or healthy individuals. Serum chemerin levels were higher in those with PDR than in those with NPDR. Thus, serum chemerin levels are a potential biomarker of the development and severity of DR in patients with T1DM. Nevertheless, future diagnostic accuracy studies are required to confirm these potential applications

Hypertension and Smoking Are Associated With Reduced Regional Left Ventricular Function in Asymptomatic Individuals The Multi-Ethnic Study of Atherosclerosis

ObjectivesThis study sought to test the hypothesis that reduced regional left ventricular (LV) function is associated with traditional risk factors including hypertension, hypercholesterolemia, and smoking in asymptomatic individuals.BackgroundCoronary artery disease is the main etiology of congestive heart failure in the U.S. and Europe. However, the relationship between risk factors for coronary artery disease and decreased myocardial function has not been studied systematically in asymptomatic individuals.MethodsThe Multi-Ethnic Study of Atherosclerosis (MESA) is a cohort study designed to investigate the nature of atherosclerosis in asymptomatic individuals. A total of 1,184 participants (45 to 84 years old) underwent tagged cardiac magnetic resonance imaging. Regional LV function was quantified by analyzing peak systolic circumferential strain (Ecc) in regions corresponding to the left anterior descending (LAD), circumflex (LCX), and right coronary (RCA) territories. The association between risk factors and strains was studied using multiple linear regression.ResultsHigher diastolic blood pressure (DBP) was associated with lower Ecc (p ≤ 0.002). The Ecc’s in the LAD territory of participants with DBP <80, 80 to 84, 85 to 89, and ≥90 mm Hg were −15.6%, −14.8%, −14.2%, and −13.7%, respectively (p < 0.001). Similar results were documented in other territories and after multivariable analysis. Smokers had lower Ecc in the LAD and RCA regions compared with nonsmokers. Furthermore, dose response relationship between cigarette consumption measured in pack-years and regional LV dysfunction by Ecc was noted (p ≤ 0.01 in LAD and RCA territories). Finally, combined diastolic hypertension and smoking was associated with a greater reduction of regional LV function.ConclusionsHigher diastolic blood pressure and smoking are associated with decreased regional LV function in asymptomatic individuals