Computer simulation of transient stability analysis of power systems.

Determination of stability characteristics of a power system is considered as a substantial issue with the increasing complexity of power systems. Power system stability is defined as the behavior of the electrical power system under sudden or sequence of disturbances when it is operating in steady state. It could be a problem of voltage stability, frequency stability or rotor angle stability depending of the type of disturbance. Transient stability which is a sub section of rotor angle stability, is concerned with the condition in which the synchronous machines in the system remain in synchronism or \u27in-step\u27 with each other when the system is subjected to severe disturbances. In multi-machine power system, transient stability analysis is an indispensable tool in the areas of planning, design, operation and research. The nonlinear nature under disturbance is not linearised for the purpose of analyzing transient stability. Therefore, the theories and methodologies for transient stability analysis based on approximations and assumptions. This study is to prepare an educational software package to understand the transient stability behavior while understanding the theories and methodologies behind it. (Abstract shortened by UMI.)Dept. of Electrical and Computer Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .J39. Source: Masters Abstracts International, Volume: 43-01, page: 0276. Adviser: G. R. G. Raju. Thesis (M.A.Sc.)--University of Windsor (Canada), 2004

Empirical studies on the performance of banks: A systematic literature review for future research

This paper intends to review research on the performance of banks to identify gaps in the current body of knowledge to justify future research directions. We use a systematic literature review method and review 164 articles from refereed journals. Content analysis reveals that most of the studies are empirical focusing on two aspects i.e. financial performance and efficiency of banks. These studies consider the impact of particular events and contexts on performance and efficiency while testing research hypotheses. However, often there is a lack of a theoretical backing for these studies. We argue that the considered events and contexts affect the risk transformation process under the financial intermediation theory. The efficiency of banks reflects the risk transformation process and causes performance. On the other hand, traditional performance indicators were based on financial measures that do not reflect the components of the risk transformation process. A sound comprehensive risk-based composite measure is required to fill this gap

Design and Validation for Laser Based Scanning Reflectometer

The goal of this study was to design and validate laser based scanning reflectometer. This senor generates information indicative of spectral reflectance characteristic of the small spot. The information indicative of the spectral reflectance characteristic can be used to determine the object in the field. Light emitted from the optical source is modulated so that reflected light from the source can be discriminated from the reflected ambient light. The influence of detector location, source location and uniformity of reflectance across the swath width were characterized. Findings and conclusions./ The calibration constant was developed as a function of sensor height, incident angle, and detector area. Results of uncertainty analysis indicate that incident angle and detector area rapidly effect the measured reflectance. The second design with off-axis parabolic reflector is capable of achieving the design objectives. The average predicted reflectance values along the swath width were 50.26% and 42.97% for rBiosystems and Agricultural Engineerin

Study on palmyrah as a material for construction

For the pursuit of sustainable development, construction of cost effective houses, with fewer disturbances to nature is a major concern. A permanent rise in the price of building materials which involves heavy capital investments is the reason for the utilization of all kinds of innovative materials. Palmyrah is an important economic resource, which is widely spread all over North East region in Sri Lanka and has found use in many structural applications. This research explores the possibility of using Palmyrah as a material for construction; as an individual structural member as well as reinforcement member in lightly loaded concrete elements. Structure of this research consisted of literature survey, basic design, construction, testing, analysing of results and discussion. There are two main objectives in this study. First objective is identifying mechanical properties of Palmyrah strips for the efficient use of Palmyrah as a structural timber. Static bending test, tensile test and compression test were conducted to identify characteristic values of strength and stiffness properties along with density and moisture content. Ultimately, Palmyrah is graded into a strength class for the benefit of timber suppliers and designers. Second objective is to determine the technical feasibility of using Palmyrah strips as an alternative for reinforcing steel in short span, lightly loaded slabs and beams. Failure loads, crack loads, mode of failure and crack patterns of test slabs and beams were observed. Flexural capacity of concrete slabs and beams reinforced with Palmyrah strips was evaluated. Results of mechanical tests showed variation of properties with maturity, height, cross section and origin. Although heartwood of Palmyrah inherits high bending, tensile and compressive strength, it has to be graded into D40 owing to its low modulus of elasticity. Strength and density of sapwood part is relatively lower due to its high moisture and starch content. It was observed in the experiments conducted that Palmyrah reinforcement enhanced the failure load of the slab by 107% and failure load of beam by 370%. Experimental failure load of slab and beam averaged 140% and 164% of theoretically predicted value respectively. Thus it is concluded that Palmyrah strips have potential to be used as reinforcement in lightly loaded slabs and beams

Common mental disorders among adult members of 'left-behind' international migrant worker families in Sri Lanka

BACKGROUND: Nearly one-in-ten Sri Lankans are employed abroad as International migrant workers (IMW). Very little is known about the mental health of adult members in families left-behind. This study aimed to explore the impact of economic migration on mental health (common mental disorders) of left-behind families in Sri Lanka. METHODS: A cross-sectional survey using multistage sampling was conducted in six districts (representing 62% of outbound IMW population) of Sri Lanka. Spouses and non-spouse caregivers (those providing substantial care for children) from families of economic migrants were recruited. Adult mental health was measured using the Patient Health Questionnaire. Demographic, socio-economic, migration-specific and health utilization information were gathered. RESULTS: A total of 410 IMW families were recruited (response rate: 95.1%). Both spouse and a non-spouse caregiver were recruited for 55 families with a total of 277 spouses and 188 caregivers included. Poor general health, current diagnosed illness and healthcare visit frequency was higher in the non-spouse caregiver group. Overall prevalence of common mental disorder (CMD; Depression, somatoform disorder, anxiety) was 20.7% (95%CI 16.9-24.3) with 14.4% (95%CI 10.3-18.6) among spouses and 29.8% (95%CI 23.2-36.4) among non-spouse caregivers. Prevalence of depression (25.5%; 95%CI 19.2-31.8) and somatoform disorder 11.7% (95%CI 7.0-16.3) was higher in non-spouse caregiver group. When adjusted for age and gender, non-returning IMW in family, primary education and low in-bound remittance frequency was associated with CMD for spouses while no education, poor general health and increased healthcare visits was significantly associated in the non-spouse caregiver group. CONCLUSIONS: To our knowledge, this is one of the first studies to explore specific mental health outcomes among adult left-behind family members of IMW through standardized diagnostic instruments in Sri Lanka and in South Asian region. Negative impact of economic migration is highlighted by the considerably high prevalence of CMD among adults in left-behind families. A policy framework that enables health protection whilst promoting migration for development remains a key challenge for labour-sending nations

WOOD DECAYING AGARIC FUNGI AND THEIR PREFERENCE TO SOME SRI LANKAN TIMBER SPECIES.

For satisfactory use of wood products in indoors and outdoors it is necessaryto understand the agents and conditions that decay or deteriorate timber. SriLanka being a tropical Country, loss of wood due to fungal attack isrelatively high. Basidiomycetes and Ascomycetes are the major wooddestroying fungi, which cause three types of decay brown rot, white rot andsoft rot.Main objective of the study was to determine the susceptibility and resistanceof different wood species to fungal attack in the natural environment. Largenumbers of wood inhabiting fungi were found in different wood speciesobserved in natural habitats, out of these species only lignicolous agaricswere studied in the present study.These agarics were collected from indoor and outdoor habitats andmacroscopic features were studied. The microscopic examination followed,together with the documentation and photographs. The identification of theagarics was undertaken by using reliable keys, illustrations and suitabledescriptions. 22 agarics spp were identified. and out of them Lentinus sppwere identified as brown rot fungi while Armillaria mellea, Schizophyllumcommune and Pleurotus spp were identified as white rot fungi.Schizophyllum commune was found on a large number of wood speciesfollowed by genus Lentinus. The appearance of mushroom fruiting bodiescoincided with the rain. Fruiting bodies of Pleurotus reticulates, Coprinusmacropus appeared during rainy seasons while Schizophyllum commune wasfound throughout the year. Most of the wood inhabiting agarics appeared asclumps.Coprinus spp and Marasmius spp were found on old rotting logs and stumps,while Schizophyllum commune, Lentinus spp and Cantharellus spp werefound on intermediately decayed tree trunks, stumps and building timbers.Schizophyllum commune was found on outer barks as well as sapwood andheartwood regions of logs and building timber. They appeared throughout the year and fruiting bodies were fresh under moist conditions, dry and leatheryin dry seasons. Schizophyllum commune was able to attack wide range ofhardwood and softwood species.Chloroxylone swietenia, Vitex altissima, Manilkara hexandra were found tobe resistant to fungal attack; therefore could be categorized as durable timberspecies in terms of fungal decay while Swietenia macrophylla, Artocarpusheterophyllus and Pericopsis mooniana were less attacked by fungi. Heveabrasiliensis, Mangifera indica were mostly attacked by fungi and hence canbe categorized as susceptible timber species. It is recommended to usepreservative treatments for the effective utilization of these perishable timberspecies

Comparison of spinal manipulation and short-wave diathermy on patients with chronic postural low back pain, in department of physical medicine at teaching hospital, Kandy, Sri Lanka

Background: Chronic postural low back pain (CPLBP) is one of the common health problems worldwide. The aim of the study was to compare the spinal manipulation (SM) and short-wave diathermy (SWD) in patients with CPLBP in department of physical medicine at teaching hospital, Kandy, Sri Lanka.Methods: Observational study was conducted. Patients diagnosed as CPLBP, who referred to the department of physical medicine (DPM), teaching hospital Kandy, were observed in the study (n=140). Seventy (70) patients were allocated for SWD and 70 for SM by the consultant. Two physiotherapists were routinely appointed for the treatments and SWD treatment by group 1 and SM was carried out by group 2. The two treatment sessions were continued once a week through four weeks. Outcomes were measured by numerical pain scale to compare with initial pain.Results: Group 1, SM consisted 39 females and 31 males, group 2, SWD 40 females and 30 males. After 4 sessions, the mean value of pain reduction from initial pain was significantly high (p<0.001) in SM group than the short-wave diathermy group in both genders. (Female: 6.410 (SM) and 4.625 (SWD), Male:6.710 (SM) and 4.333 (SWD). Further the mean values showed that there was a significant pain reduction during the initial treatment session than 2nd, 3rdand final sessions in both treatment groups.Conclusions: Pain reduction was more pronounced in the first treatment session in both methods. SM is more effective for the treatment of CPLBP irrespectively the age and gender when compare to the SWD in the study population. Therefore, SM could apply on CPLBP patients with higher effective treatment

Development of a Real-Time, Secure and Reliable Automobile Service Center

Lack of ambition will prevent you from moving forward in life, as much like a car without petrol. The majority of people on earth isobsessed with automobiles. We have provided you with a web application for Real time automobile service that functions effectively on all the platforms. Occasionally, automobiles and other motorized vehicles require maintenance. They must be maintained clean, just as humans practice proper hygiene. They run on dirty streets and in polluted environment. They are subjected to loads that harm them since they travel on uneven roads with obstacles. Therefore, it is necessary to maintain automobiles and other motorized vehicles on a regular basis. This project aims to keep service centers running smoothly in terms of things like vehicle maintenance, customer quotation generation, vehicle servicing, spare parts sales, customer information, and customer feedback. The system is efficient at generating reports that will make service center routine maintenance easy.Additionally, it can handle car repairs, insurance, payments, delivery, etc. This project will be very helpful to customers who want to fix or repair their cars. As a result, we develop a software that is both compatible and unique

Pressure-induced collapsed-tetragonal phase in SrCo2As2

We present high-energy x-ray diffraction data under applied pressures up to p = 29 GPa, neutron diffraction measurements up to p = 1.1 GPa, and electrical resistance measurements up to p = 5.9 GPa, on SrCo2As2. Our x-ray diffraction data demonstrate that there is a first-order transition between the tetragonal (T) and collapsed-tetragonal (cT) phases, with an onset above approximately 6 GPa at T = 7 K. The pressure for the onset of the cT phase and the range of coexistence between the T and cT phases appears to be nearly temperature independent. The compressibility along the a-axis is the same for the T and cT phases whereas, along the c-axis, the cT phase is significantly stiffer, which may be due to the formation of an As-As bond in the cT phase. Our resistivity measurements found no evidence of superconductivity in SrCo2As2 for p <= 5.9 GPa and T >= 1.8 K. The resistivity data also show signatures consistent with a pressure-induced phase transition for p >= 5.5 GPa. Single-crystal neutron diffraction measurements performed up to 1.1 GPa in the T phase found no evidence of stripe-type or A-type antiferromagnetic ordering down to 10 K. Spin-polarized total-energy calculations demonstrate that the cT phase is the stable phase at high pressure with a c/a ratio of 2.54. Furthermore, these calculations indicate that the cT phase of SrCo2As2 should manifest either A-type antiferromagnetic or ferromagnetic order.Comment: 6 pages, 5 figure