Solar and wind energy conversion system

Solar and wind energy conversion systems, interfaced to the utility grid using DC-AC inverters and AC-DC-AC converters respectively, are now gaining wide-spread interests because of the fast depletion of fossil fuels and the detrimental environmental impacts created by the conventional methods of energy generation. Comparatively, solar and wind energy are cleaner, and more importantly, they are abundantly available, implying that sustainability is definitely guaranteed if energy can smoothly he harnessed from these two main renewable sources. But unfortunately, the smooth harnessing of energy from the sun and wind is not as straightforward as extracting energy from fossil fuels, and they usually require the adoption of advanced power electronic and control technologies. Therefore, opportunities for researching solar and wind energy systems are abundant, where one topic proposed for investigation in this thesis is the performing of case studies under fault conditions tor a chosen four-bus network with solar and wind energy sources interconnected.Master of Science (Power Engineering

EVALUATION OF DESIGN-BID-BUILD (D-B-B) PROJECTS WITH AND WITHOUT AGENCY CONSTRUCTION MANAGEMENT

Agency CM is a construction management system, and is a way to manage the process of construction. Agency Construction Management when paid on hourly Fee tempts to work hours that are not needed to maximize fee. When Agency CM is paid by Lump sum Fee or remunerated by a percentage of the Project Cost, Agency CM is only committed to provide defined services and results for a lump sum Fee. So the Agency CM may be tempted to provide less service than what was contracted for to increase profits and may maximize profits by cutting corners on services at risk of not obtaining expected results. Hence there is a need for the owner to understand whether there is improvement in Project Performance when Agency CM is contracted with any Project Delivery System. Design-Bid-Build (D-B-B), Design-Build (D-B), and Construction Management at risk (CM at - Risk) are the three principal project delivery systems. Agency CM can be used with any type of Project Delivery System. This necessitates a comprehensive investigation in to the performance of projects delivered with Agency CM and projects delivered without Agency CM. This study evaluated the project performance metrics such as Project Cost, Project Schedule and Project quality in Projects where Design-Build (D-B-B) Project Delivery System was used with Agency CM and Projects where Design-Bid-Build Project Delivery System was used without Agency CM. The study included literature review, designing a questionnaire, collecting data from 200 Design –Bid-Build (D-B-B) projects of which 100 projects where Agency CM was used and 100 projects where Agency CM was not used. Analysis of data pertaining to project performance metrics was done by using SPSS statistical software. An understanding of this study can help an owner/client better select the D-B-B project delivery system either with or without Agency Construction management

Corkscrewing of retinal arterioles leading to diagnosis of coarctation of aorta

Coarctation of aorta (CoA) usually leads to elevation of blood pressure above the site of obstruction and this elevated blood pressure probably gets transferred and is reflected in the retinal arterioles producing certain signs of hypertensive retinopathy. Fundus examination helps in differentiating hypertension due to CoA from other causes of juvenile hypertension, as corkscrewing of retinal arterioles is seen only in CoA but not in other conditions. A 16 year hypertensive male who was on antihypertensive treatment presented for routine checkup. On examination his visual acuity was 6/6 in both eyes. Funduscopy of both eyes revealed a normal optic disc with generalised narrowing of arterioles and broadened light reflex. The arterioles showed corkscrew tortuosity (U shaped arterioles). Based on the fundus findings, CoA was suspected and the patient was referred for cardiac evaluation. Echocardiogram revealed post ductal CoA. In juvenile hypertension, careful examination of the fundus can provide a clue to the systemic diagnosis and this case highlights the importance of ophthalmoscopic examination in diagnosing a potentially fatal systemic disease

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Not AvailableA hurdle technology-based approach for the reduction in immunogenicity of shrimp major allergen, tropomyosin was investigated by combining electron beam irradiation at 5 kGy and boiling, autoclaving, trypsin and chymotrypsin treatments along with peeled raw shrimp as control. Shrimp extracts were prepared from the irradiated sample and evaluated SDS PAGE profile, IgE binding ability and immunogenicity of tropomyosin using pooled sera of shrimp sensitive individuals. Electron beam irradiation resulted in significant (p < 0.05) decrease in the IgE activity in the case of all treatments. The SDS PAGE analysis showed the presence of tropomyosin in all the treatments except autoclaving in combination with or without electron beam irradiation. A pronounced reduction in allergenicity was observed in the treatment of autoclaving in combination with electron beam irradiation. The combined application of autoclaving and electron beam irradiation can be utilized for the preparation of hypoallergic shrimp.Not Availabl