The integration of input filters in electrical drives

PhD ThesisThe integration of passive components such as inductors and capacitors has gained significant popularity in integrated drive research, and future power electronics systems will require more integrated and standardised packages. These give rise to better power density and improved performance. However, packaging techniques and passive components have been considered a technological barrier which is limiting advances in power electronics. The focus on size reduction should be turned towards the passive components, such as converter chokes, DC-link capacitors and electromagnetic interference (EMI) filters, and achieving greater power density depends on innovative integration concepts, flexibility in structures and extended operating temperature ranges while system integration and modularity are not mutually exclusive. This research considers the possibility of integrating input power filter components into electric machines. Particular attention is paid to the integration of electromagnetic line filter inductors to give better utilisation of the motor volume and envelope. This can be achieved by sharing the machine’s magnetic circuit. An LCL line filter has been chosen to be integrated with a gridconnected permanent magnet synchronous machine. Machines have been proposed in this study for low speed (3000 RPM) and high speed (25000 RPM) operation. The two machines have similar dimensions, but the low-speed machine is less challenging in terms of losses and filter integration, so attention is directed more to the high-speed machine. Both are supplied with low- and high-power drives at power ratings of 4.5 kW and 38 kW respectively. Several novel techniques have been investigated to integrate filter inductors into the electrical machines to produce a single mechanically packaged unit without significant increases in size and losses. Different approaches have been simulated using finite element analysis (FEA) to assess the effectiveness of the integration of passives within the machine structure. Each design has been iteratively optimised to determine the best mass of copper and core for the integrated filter inductors, targeting parity in power density when compared to traditional separate packages. The research demonstrates that an approach utilising a double-slot stator machine (named the integrated double slot (IDS) machine) with input filters wound into the outermost slots is the most appropriate choice in terms of achieving higher power density. The integrated filter inductors mimic the electromagnetic behaviour of the discrete industrially packaged inductors but with a volume reduction of 87.6%. A prototype of the IDS machine design of a 38 kW, 25000 RPM, including filter inductors was manufactured and testedthe General Electricity Company of Libya (GECOL), the Engineering and Physical Sciences Research Council (EPSRC), and the Engineering Doctorate scheme at Newcastle University

Challenges to Safe Wheat Storage

There are enormous challenges facing wheat storage, which is the most important crop in existence. Wheat is one of the most famous and important plants in human history. There is no country in the world that does not give up wheat yields. Countries of the world vary and differ in their production and consumption of that important plant. Since ancient times, humans have stored wheat grain in special places. Storage areas were developed until the current silos were reached. With large quantities of wheat stored in silos, there are many challenges to the healthy environment of storage. One of the most important challenges facing quality of wheat stored in silos is the spread of conidia and spores of many dangerous fungi on wheat grains. One of studies conducted by the authors proved presence of some of notorious fungi on and inside wheat mass stored in the silo under study. Aspergillus flavus, A. niger, Circinella umbellata, Gliocladium sp., Penicillium frequentans, P. islandicum, and Ulocladium atrum were isolated from wheat samples. All seven isolated fungi demonstrated their ability to analyze human red blood cells with different strengths. These results are consistent with previous studies that confirm the seriousness of presence of these fungi on the health of dealers and exposers especially with bad storage and humidity

Olive-Pressed Solid Residues as a Medium for Growing Mushrooms and Increasing Soil Fertility

Organic fertilizer is the core of organic farming, which represents the most important way to provide crops and agricultural products that are safe and free of any chemical components and pesticides. From this point of view, the purpose of this study is to provide a source of organic fertilizers which was formerly an environmental problem. The northwestern region of Saudi Arabia is flourishing with olive production, leaving huge amounts of residues called olive press cake (OPC). These wastes are a major environmental pollution despite their good content of carbohydrates, protein, oil and cellulose alongside phenols and lignin. We tested the cultivation of Gliocladium roseum, Pythium oligandrum and Trichoderma harzianum and the mushroom Pleurotus ostreatus on OPC in order to reduce the high percentage of phenols that impede the germination of some plant seeds. Gliocladium roseum, Pythium oligandrum and Pleurotus ostreatus were able to reduce the percentage of phenols to more than 40% and thus support germination of seeds of Eruca sativa. This study gave than one benefit: firstly, reducing phenols that impede the germination of seeds. Secondly, Gliocladium roseum and Pythium oligandrum work against some plant diseases and also produce plant-like hormones that increase growth of plants

Design, synthesis and antitumor evaluation of novel pyrazolopyrimidines and pyrazoloquinazolines

A series of N-aryl-7-aryl-pyrazolo[1,5-a]pyrimidines 18a–u and N-aryl-pyrazolo[1,5-a] quinazolines 25a–c were designed and synthesized via the reaction of 5-aminopyrazoles 11a–c with enaminones 12a–g or 19, respectively. The new compounds were screened for their in vitro antitumor activity toward liver (HepG-2) and breast (MCF-7) human cancer cells using 3-[4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide MTT assay. From the results, it was found that all compounds showed dose-dependent cytotoxic activities against both HepG-2 and MCF-7 cells. Two compounds 18o and 18a were selected for further investigations. Cell cycle analysis of liver (HepG-2) cells treated with 18o and breast (MCF-7) cells treated with 18a showed cell cycle arrest at G2/M phase and pro-apoptotic activity as indicated by annexin V-FITC staining.publishedVersio

The Effectiveness of Using a Cognitive Style-based Chatbot in Developing Science Concepts and Critical Thinking Skills among Preparatory School Pupils

The research investigated the effectiveness of using a cognitive style-based chatbot in developing science concepts and critical thinking skills among preparatory school pupils. To achieve the aim of the research, the researchers applied the two groups' quasi-experimental design and utilized three instruments as follows;1) Budner scale to measure the tolerance of ambiguity; 2) Science concepts achievement test developed by the researchers and implemented before and after applying a cognitive style-based chatbot; 3) The critical thinking skills test developed by the researchers to identify four critical thinking skills required for grade 8 level and implemented before and after applying a cognitive style-based chatbot. The participants were chosen randomly from eighth-graders (N=50) at HOIS (Hurghada Official International School), Red Sea Governorate, Egypt. The researchers divided participants into two experimental groups of 25 pupils (EGA) and (EGB) according to their cognitive style as tolerant or intolerant of ambiguity. Quantitative results showed the significant mean differences between the scores of participants at level (0.005 ≥) in the pre-post testing procedures in favor of the post-testing for both dependent variables (science concept and critical thinking skills). Results indicated the positive impact of utilizing a cognitive style-based chatbot in developing science concepts and critical thinking skills for preparatory school pupils. So, the researchers recommended employing chatbots in learning science for their high effectiveness in developing science concepts and critical thinking skills among preparatory school pupils in Egypt

The protective effects of cerium oxide nanoparticles against hepatic oxidative damage induced by monocrotaline

Kamal A Amin1, Mohamed S Hassan2, El-Said T Awad3, Khalid S Hashem11Department of Biochemistry, 2Department of Internal Medicine, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt; 3Department of Biochemistry, Faculty of Veterinary Medicine, Cairo University, Cairo, EgyptObjective: The objective of the present study was to determine the ability of cerium oxide (CeO2) nanoparticles to protect against monocrotaline (MCT)-induced hepatotoxicity in a rat model.Method: Twenty male Sprague Dawley rats were arbitrarily assigned to four groups: control (received saline), CeO2 (given 0.0001 nmol/kg intraperitoneally [IP]), MCT (given 10 mg/kg body weight IP as a single dose), and MCT + CeO2 (received CeO2 both before and after MCT). Electron microscopic imaging of the rat livers was carried out, and hepatic total glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPX), glutathione S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT) enzymatic activities were quantified.Results: Results showed a significant MCT-induced decrease in total hepatic GSH, GPX, GR, and GST normalized to control values with concurrent CeO2 administration. In addition, MCT produced significant increases in hepatic CAT and SOD activities, which also ameliorated with CeO2.Conclusions: These results indicate that CeO2 acts as a putative novel and effective hepatoprotective agent against MCT-induced hepatotoxicity.Keywords: monocrotaline, ceruim oxide nanoparticle, hepatotoxicity, oxidative stres

Effect of Long Term Pulsed Electromagnetic Field on Postmenopausal Stress Urinary Incontinence

Pulsed electromagnetic therapy is used to activate the pudendal nerve, which then activates the pelvic floor musculature, which is supposed to increase urethral closure and improve the stress urinary incontinence (SUI). Aim of the study: was to detect the long-term efficacy of pulsed electromagnetic therapy on post-menopausal SUI. Subjects and Methods: Forty postmenopausal females complaining from mild or moderate degree of SUI. They were recruited randomly from outpatient clinic of gynecological department in Al-Mataria teaching hospital, Egypt. Their ages ranged from 50 to 60 years old. The BMI of the patients was not exceeding 35 Kg/m2. They were multipara. Their deliveries were normal vaginal delivery. All women were treated by pulsed electromagnetic field 2 sessions/ week for 8 weeks. The vaginal squeeze pressure and symptoms of SUI were assessed pre-magnetic therapy, post magnetic therapy at the end of 8 weeks, follow up at 3, 6& 12 months by biofeedback (Myomed 632v) and (UDI-6) respectively. Results: The vaginal squeeze pressure was significantly increased (p= 0.001), and UDI-6 was significantly decreased (p= 0.001), at post magnetic therapy, follow up at 3, 6& 12 months when compared with their corresponding values measured pre-magnetic therapy. There was no significant difference (p\u3e 0.05) between post magnetic therapy measurements compared at different time assessment at 3, 6& 12 months. Conclusion: The encouraging results of our study supported that PEMF has long -term effect as a unique therapeutic modality for the treatment of postmenopausal SUI

Electrocatalytic Evolution of Oxygen Gas at Cobalt Oxide Nanoparticles Modified Electrodes

The electrocatalysis of oxygen evolution reaction (OER) at cobalt oxide nanoparticles (nano-CoOx) modified GC, Au and Pt electrodes has been examined using cyclic voltammetry. The OER is significantly enhanced upon modification of the electrodes with nano-CoOx, as demonstrated by a negative shift in the polarization curves at the nano-CoOx modified electrodes compared to that obtained at the unmodified ones. Scanning electron microscopy (SEM) revealed the electrodeposition of nanometer-size CoOx (average particle size of 200 nm) onto GC electrode. Optimization of the operating experimental conditions (i.e., solution pH and loading level of nano-CoOx) has been achieved to maximize the electrocatalytic activity of nano-CoOx modified electrodes. It has been found that the electrocatalytic activity of the nano-CoOx modified electrodes towards the OER is pH and loading level dependent, while it is substrate independent. The low cost as well as the marked stability of the thus-modified electrodes make them promising candidates in industrial water electrolysis proces

Effect of sulphate, chloride and elevated temperature on the properties of Egyptian slag binder

The present research aims to explain the physico-chemical and mechanical characteristics of alkali activated slag geopolymer binder (AASGB). Commercial sodium hydroxide (SH) and sodium silicate liquid (SSL) are utilized as an alkaline activator at different temperature namely 25oC and 65oC. The hydration characteristics and physico-mechanical properties are illustrated through the determination of combined water contents Wn), combined slag, total porosity (TP), compressive strength (CS), bulk density (BD) and XRD analysis as spectroscopic tools upto 180 days. The durability of the AASGB against aggressive ions (sulphate and chloride ions ) as well as effect of elevated temperatures upto 1000oC are studied. The activated binders are immersed under 5% MgSO4 and/or 5%MgCl2 solutions upto12 months. The data showed that the higher concentration of SH (1mol/kg) at 65oC exhibited the highest resistance to elevated temperature upto 1000oC as well as given a high resistance against sulphate and chloride attack

COATING OF GUAVA (PSIDIUM GUAJAVA L.) FRUITS WITH BOTANICAL EDIBLE OILS FOR SHELF LIFE AND FRUIT FLIES

Guava (Psidium guajava L.) fruit is a popular nutritious dessert in Sudan. It is famous for its medicinal values as a prompt cure for digestive disorders and respiratory ailness this besides being a rich source of C vitamin. This fruit is highly amenable to fruit fly attack and it is a harbor of eggs of five different species [Ceratitis capitata Wied.; Ceratitis quinaria Bez.; Ceratitis cosyra Wlk.; Bactrocera invadens De Trusta and White and Bactrocera zonata (Saunders)] in Sudan. This is stimulating to a chain of endless research to combat these notorious pests which account for huge losses in this crop that reach up to 80% or even more. This research aimed at evaluating the effect of oil coating on fruit fly infestation and the quality indexes in guava fruit using five different botanical edible oils. The results showed that groundnut (Arachis hypogaea L.) (GNO), sesame (Sesamum indicum L.) (SO), baobab (Adansonia digitata L.) (BO), olive (Olea europaea L.) (OO) and neem (Azadirachta indica A. Juss) (NO) oils effected a corrected disinfestation of 80, 72, 56, 52 and 28% in test fruits brought from Kadaro orchards North Khartoum, respectively. The corresponding average readings of maggots in infested fruits were 4, 17, 11, 5, 7 and [10 (for the first 4) and 26 for NO] in the control. Two essential quality indexes were checked in test fruits which included fruit color (FC) and firmness (FF). The corrected test readings reflected 64, 80, 44, 52,-4 and [8 (for the first 4) and 20 for NO] in the control sustained FC for GNO, SO, BO, OO, NO and the control, respectively. However, the corresponding readings for FF were 3 (medium) for all oils and 4 (soft) for the controls. These results reflect a potent and the best efficacy of peanut and sesame oils, of the five test oils, in controlling fruit flies in guava and extending its shelf life