Mitigation and control of electric fields on spacers' surfaces in gas insulated systems

Research in the area of gas insulated systems' (GIS) reliability is still attracting a considerable attention from the electric utilities and the scientific community in many countries. Solid insulating spacers in GIS represent the weakest points in these systems, and several troubles and systems' outages have been reported allover the world due to their failure. So it is essential to determine the electric field distribution along their surfaces and hence evaluate the degree of their reliability. Several researchers evaluated the electric field distribution on the spacers' surfaces in gas insulated systems and studied the effects of their dimensions and its relative permittivity on the electric field stress distribution. The outcome of these investigations is that the electric field stresses intensify around the triple junction and they are the main reason to initiate breakdown in gas insulated systems. Due to the previously mentioned spacers' troubles, they should be precisely designed to realize more or less uniform field distribution along their surfaces. The spacer's profile is considered the main variable, which controls the field distribution and hence field uniformity can be achieved by adopting the appropriate profile. This paper uses the artificial neural network technique "ANN" to optimize the electric field on the spacer's surface, and introduces a novel method based on replacing the spacer's material with a constant permittivity by another one having a functionally graded permittivity to optimize and control the electric field along its surface. The use of the ANN enabled the authors to design a spacer with a pre-selected almost uniform field along its surface. The error between the target field and the evaluated one is ± 5%. Also the use of FGM reduced the electric field near the triple junction at the enclosure to les than 50% in some cases

Synthesis And Characterization Of PVP Based Catalysts For Selected Application In Catalysis

This research aims to study the catalyst activity in specific reactions and the characteristics of the catalyst in order to optimize its performance. This research investigates PVP based catalysts and their properties and applications. PVP was prepared in combination with different metal oxides in order to be tested for different catalytic applications including dye removal. Methyl orange was used as a dye and different concentrations were tested against different metallic ions in order to optimize the catalyst for being used in dye removal applications. Spectrophotometer was used to calculate the concentration of the dye before and after catalyst exposure and investigate the relation between contact time and concentrations. Applying different contact time to the same weight percent of PVP based catalyst with metallic ions revealed that increasing the contact time with a good shaking lead to decrease in the concentration of the dye mixed with the sample. The tests showed that the mixture between PVP and Nickel has the best dye removal within the other metal ions (copper and ferric) as well it showed that ferric has the least effect on dye removal. Wide angle x-ray diffraction (WA-XRD) was applied to different sample copper with PVP and ferric with PVP

Screening for More than 1,000 Pesticides and Environmental Contaminants in Cannabis by GC/Q-TOF

A method has been developed to screen cannabis extracts for more than 1,000 pesticides and environmental pollutants using a gas chromatograph coupled to a high-resolution accurate mass quadrupole time-of-flight mass spectrometer (GC/Q-TOF). An extraction procedure was developed using acetonitrile with solid phase extraction cleanup. Before analysis, extracts were diluted 125:1 with solvent. Two data mining approaches were used together with a retention-time-locked Personal Compound Database and Library (PCDL) containing high-resolution accurate mass spectra for pesticides and other environmental pollutants. (1) A Find-by-Fragments (FbF) software tool extracts several characteristic exact mass ions within a small retention time window where the compound elutes. For each compound in the PCDL, the software evaluates the peak shape and retention time of each ion as well as the monoisotopic exact mass, ion ratios, and other factors to decide if the compound is present or not. (2) A separate approach used Unknowns Analysis (UA) software with a peak-finding algorithm called SureMass to deconvolute peaks in the chromatogram. The accurate mass spectra were searched against the PCDL using spectral matching and retention time as filters. A subset PCDL was generated containing only pesticides that are most likely to be found on foods in the US. With about 250 compounds in the smaller PCDL, there were fewer hits for non-pesticides, and data review was much faster. Organically grown cannabis was used for method development. Twenty-one confiscated cannabis samples were analyzed and ten were found to have no detectable pesticides. The remaining 11 samples had at least one pesticide and one sample had seven detectable residues. Quantitative analysis was run on the confiscated samples for a subset of the pesticides found by screening. Two cannabis samples had residues of carbaryl and malathion that were estimated to be about 10 times greater than the highest US Environmental Protection Agency tolerance set for food and about 4,000 times greater than the Canadian maximum residue limits for dried cannabis flower

Isolation of catechins from Cycas armstrongii Miq. of an Egyptian origin

The phytochemical investigation of Cycas armstrongii Miq. leaves and twigs using different chromatographic techniques led to the isolation of three catechin monomers; catechin (1), epicatechin (2), and epigallocatechin-3-gallate (3), for the first time from this species. The chemotaxonomic significance of the isolated compounds is discussed in the rest of this article

Synthesis, Characterization And Selected Application Of Chitosan-coated Magnetic Iron Oxide Nanoparticles

In this research, we report an efficient method to prepare highly active chitosan-coated magnetic iron oxide nanoparticles by implementing co-precipitation technique which is used for wastewater treatment applications. Chitosan-coated magnetic iron oxide nanoparticles were synthesized and characterized using TEM, XRD, and XPS. A comparative study has been made between chitosan powder and chitosan coated with magnetic nanoparticles with respect to the rate of adsorption of copper from aqueous solution. It was also experimentally verified that chitosan coated magnetic iron oxide nanoparticles are much more effective in adsorption of heavy metals than chitosan powder and it takes just few minutes instead of hours. Moreover, the super paramagnetic behavior of the chitosan coated with iron oxide nanoparticles enabled the easy removal through applying an external magnetic field and hence leaving the solution free from copper

Evaluation of different biochemical markers in prediction of metabolic syndrome in polycystic ovary syndrome patients

Background: Polycystic ovary syndrome (PCOS) is the commonest cause of chronic hyperandrogenic anovulation. Insulin resistance and compensatory hyperinsulinemia are keys of the pathogenesis of PCOS. It is also considered as a metabolic disorder. Since the components of metabolic syndrome (MBS) namely obesity, glucose intolerance, dyslipidemia, and hypertension are the common features of this syndrome. The association between MBS and PCOS can be explained by different theories as insulin resistance, obesity, and related adipose tissue factors (adipocytokines) independent of insulin resistance are the main pathogenic contributors to both disorders.Methods: A total of 143 women with PCOS were recruited as study subjects. All participants were subjected to anthropometric measurements, clinical assessment, and biochemical tests [fasting glucose, fasting insulin, and homeostatic model assessment-insulin resistance (HOMA-IR)]. Hormonal profile particularly leptin and homocysteine levels were also evaluated.Results: 25 patients (17.4%) out of 143 women with PCOS met the criteria for MBS. Patients with MBS had significantly higher body mass index, blood pressure, HOMA-IR, leptin, and homocysteine levels compared to PCOS only patients. When HOMA-IR cut off was ≥4.3 sensitivity and specificity were 90%, 88.6%, but when leptin level was ≥34.5 the corresponding statistics were 79.6%, 75.5%.Conclusions: Serum leptin, homocysteine, HOMA-IR as well as other biochemical markers are significantly higher in women with PCOS and MBS compared to PCOS only women. PCOS is associated with various factors like insulin resistance, obesity, and dyslipidemia. Consequently, adipocytokines and HOMA-IR play important role in the prediction of MBS in patients with PCOS

Epidemiology and Laboratory Investigations in Children with Chronic Liver Diseases in Sohag University Hospital

Background: Chronic liver diseases encompasse metabolic, genetic, drug-induced and inflammatory diseases. The causes of liver disease in children vary with age. In countries where HBV is endemic, perinatal transmission remains the most important cause of chronic infection. The prevalence of hepatitis C infection was much higher in individuals receiving blood products for conditions such as thalassemia or haemophilia. Glycogen storage disorders may present with chronic liver disease.Objectives: To study epidemiological features and laboratory investigations that may affect the incidence in children with chronic liver disease.Patients and methods: Our study included 30 treatment-naïve patients with chronic liver disease of different aetiologies referred to the Department of Pediatrics, Sohag University Hospital. All patients were subjected to history taking, general and local examinations, laboratory investigations and measurement of serum ceruloplasmin.Results: The mean age of children was 10.23 years in case group and 10.75 years in control group, ranging between 5.5 to 15 years. The majority of patients were females (53.3%) and the remained patients were males (46.7%). There was significant difference between patient and control groups as regard total leucocytic count. Also, there were significant differences between the two groups regarding ALT, AST, total bilirubin, direct bilirubin and concentration and high significant differences regarding serum albumin and prothrombin time.Conclusion: Total leucocytic count, AST, ALT, bilirubin, and serum albumin concentration, and prothrombin time are significant investigations to rule out diagnosis and anticipate complications in patients with chronic liver diseases. ALT and PT are early sensitive markers that anticipate liver decompensation

Role of Ultrasonic Elastography in the Evaluation of Fibrosis in Children with Chronic Liver Disease in Comparison to Liver Biopsy

Background: Chronic liver illnesses can be caused by a variety of factors, including metabolic, genetic, drug-induced, inflammatory, structural, dietary, and immunological factors. Even with Computed Tomography (CT) scans or Magnetic Resonance Imaging (MRI), liver fibrosis makes diagnostic imaging difficult in chronic liver injury. Percutaneous liver biopsy is the gold standard for diagnosing, grading, and monitoring liver fibrosis in children, but it is painful, invasive, requires heavy sedation, and has numerous complications such as bleeding. Objectives: The aim of the current work was to assess and measure liver stiffness in children with chronic liver disease using real-time elastography (RTE), compare the results to histopathological findings obtained after performing a percutaneous liver biopsy, and investigate the availability of noninvasive safe liver elastography as a future replacement for this invasive tool in the evaluation and grading of liver fibrosis.Patients and methods: This hospital-based cross-sectional comparative study included a total of 30 individuals with chronic liver disease of various etiologies with age ranged from 4-16 years, attending at Department of Pediatric, Sohag University Hospitals. This study was conducted between January 2017 to December 2019. A control group of ten healthy people was also included in the investigation.Results: The degree of liver stiffness measured by the last ultrasonic elastography was greater in the patient group than in the control group, with a statistically significant difference between the two groups. Except for F0-F1 and F3-F4, there was a substantial relationship between fibrosis stage and liver stiffness assessment by sonoelastography, where the difference was significant between every two individual groups. There was a strong link between biopsy diagnosis and liver stiffness measurement.Conclusion: It could be concluded that in adults, ultrasonic elastography is a well-established approach for assessing liver fibrosis. The utility of elastography in the follow-up of children with chronic liver disease might be increased

Foresight for sustainable energy policy in Egypt: results from a Delphi survey

International audienceThis paper presents energy opportunities, particular areas of high potential and reflections on energy challenges in Egypt by the year 2040. Energy foresight significantly contributes in the effective review and formulation of national energy policies and strategies. In this work, 350 experts participated in real-time Delphi survey and responded to a set of structured and cross-linked questionnaires that aim to assess and provide future dimension to the energy sector in Egypt. Priorities are presented across 14 energy cluster-areas with 180 identified topics. The two-round Delphi study with an iterative process was performed to determine and measure the expectations of the different stakeholders with specific emphasis on the prospects of renewable energy and energy efficiency. The designed cross-linkages between survey components allowed the systematic pooling and convergence of knowledge in addition to the technical insights and different perspectives. About 50% of Egypt's energy demand was foresighted to be met by renewable energies around 2030. The results showed that all types of energy would not only provide economic and environmental benefits but also improve living standards. This work demonstrates that involving large diversity of expertise and different stakeholders, comprising heterogeneous groups, in foresight studies would potentiate the forecasting power, reduce the polarization effect, and enhance the reliability of the foresight exercise

ANTIDIABETIC, HYPOLIPIDEMIC AND ANTIOXIDANT ACTIVITIES AND PROTECTIVE EFFECTS OF PUNICA GRANATUM PEELS POWDER AGAINST PANCREATIC AND HEPATIC TISSUES INJURIES IN STREPTOZOTOCIN INDUCED IDDM IN RATS

Objective: There is a growing interest in traditional medicinal plants since they contain medicinally active products to remedy many diseases. Punica granatum (PG) has many medicinal applications. The aim of this study was to investigate the antidiabetic, hypolipidemic, antioxidant and hepato-pancreatic protective effects of PG peel powder (PGPP) on streptozotocin (STZ) induced diabetic rats.Methods: Male Swiss albino rats became diabetic with insulin-dependent diabetes mellitus (IDDM) after a single intravenous injection of STZ (50 mg/kg). IDDM-rats received either a daily oral dose of PGPP (200 mg/kg), or insulin for 20 days. On day 21, rats were sacrificed and levels of fasting blood glucose (FBG), aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, lipid profile, lipid peroxidation (LPO), nitric oxide (NO), superoxide dismutase (SOD), and total antioxidant capacity (TAC) were estimated. Histopathological studies of liver and pancreas were performed.Results: There was a significant elevation in FBG, AST, ALT activities, NO and LPO levels for induced IDDM. In contrast, albumin level, SOD activity, and TAC exhibited the significant decline. In addition, there was marked lipid profile disturbances, and histopathological changes of liver and pancreas. Following PGPP supplementation, the levels of all the above-mentioned factors were back to normal. Also, liver architecture and the size of an islets of Langerhans of the pancreas were almost back to normal. The effect of PGPP was more pronounced when compared with insulin.Conclusion: PGPP is an effective alternative for the treatment of IDDM through the regeneration of β cells of pancreas and via its strong antioxidant properties.Â