Power Transformer Fire and Explosion: Causes and Control

An increasing number of failures of power transformers over the world has led to greater interest in building up much needed expertise in electric power transformers, from its design to both preventive and prescribed maintenance. Winding failure is a frequent cause of transformer failure, bushing failure leads of fire and explosion, but it is still uncertain whether the increasing failure of transformers may be related to increasing lightning activity or increasing electric energy of the transient, surge voltages generated by lightning, especially long continuing currents and rate of rise of currents. But there are other important causes as well which need close attention, including wearing out of the contact points of tap changers in power generating and substation transformers, and poor maintenance of transformer oil. This paper seeks to review some of the well-known causes that lead to transformer fire and explosion, and highlights the important parts of the power transformer that need careful selection, installation, maintenance and condition monitoring. Moreover the containment of fires and measures that help to prevent transformer explosions in case of transformer fires are also discussed. Keywords: Embedded systems, Smart Antenna; Adaptive Array; Artificial Neural Network

Prevalence of somatisation and psychologisation among patients visiting primary health care centres in the State of Qatar

Background: Medically unexplained somatic complaints are among the most common clinical presentations in primary care in developing countries and they are considerable burden for patients and health care system. Objectives: The aim of this study was to determine the prevalence of somatisation in comparison to psychologisation among a sample of Qatari patients who were visiting primary health care (PHC) centres and to investigate the clinical and socio-demographic characteristics of somatisers (STs) and psychologisers (PGs). Method: The survey was conducted among PHC Qatari patients during the period from January to July 2007. About 2,320 patients were approached, of whom 1,689 agreed to participate and responded to the questionnaire. Among the studied Qatari patients, 404 patients were identified for clinical interview. The first stage of the study was conducted with the help of general practitioners, using the 12-item General Health Questionnaire. The second stage was carried out by a consultant using the Clinical Interview Schedule. A specific operational criterion was used to identify STs and PGs. Results: The prevalence rate of STs among the total studied sample was 12.4%, while the PGs were 11.5%. Among the identified psychiatric cases, the proportion of STs (52%) was higher than PGs (48%). Most of the diagnostic categories were more prevalent among PGs. The dissatisfaction at work and stressful life events within 12 months before the onset of the presenting symptoms were the three postulated determinants which were significantly more among STs than PGs. Conclusion: The prevalence of somatised mental disorder was little higher than the psychologised mental disorder. The prevalence of somatisation and psychologisation is comparable with other reported studies from the Middle-East and Western countries. Dissatisfaction at work and stressful life events were significantly higher among STs than PGs

Accreditation Handbook

This handbook is a reference for the faculty, academic and administrative staff on the process and procedure involved in preparing and obtaining accreditation. This handbook also serves as a valuable guide for the faculty to develop an assessment plan in the process of the future accreditation

Accreditation Handbook

This handbook is a reference for the faculty, academic and administrative staff on the process and procedures involved in preparing and obtaining accreditation. This handbook also serves as a valuable guide for the faculty to develop an assessment plan in the process of future accreditation

Assessment of Endometritis in Arabian Mare

This study aimed to employ different methods for diagnosis of endometritis in Arabian mare. The study was conducted on 88 barren Arabian mares. After establishing the breeding history and completing the clinical examination, 50 of them were diagnosed as endometritis. Two swabs were obtained for bacteriological culture and cytological smears. Biopsy specimens were taken from the endometrium for histological examination. The results revealed that the ageing and the abnormal vulvar conformation were predisposing factors for endometritis. The number of mares affected with endometritis were 10, (20%) 13 (26%) and 27 (54%) in nullipara, primipara and pluripara mares respectively. Mares affected with endometritis were 6 (12%), 20 (40%), 18 (36%) and 6 (12%) in relation to body scoring 1, 2, 3 and 4 respectively. Bacteriological and mycological examinations of the uterine culture were positive in 41 (82%) and in 5 (10%) animals respectively. No growth was recorded in 4 swabs (8%).  Streptococcus equi zooepidemicus were found to be the most common potential uterine bacterial pathogens (39.1% ) followed by E coli (21.7%). Cytological examination was positive in 60% (n=30) and negative in 40 % (n=40). The histopathological investigation revealed that 10/50 cases (20%), 18/40 cases (45.0%), 11/40 cases (27.5%), 7/40 cases (17.5%) and 4/40 cases (10.0%) were diagnosed as normal endometrium (Grade I), mild endometritis (Grade II A), moderate endometritis (Grade II B), severe endometritis (Grade III) and uterine atrophy respectively. Keywords: Arabian mare, biopsy, cytology, endometritis   Animal Production 14(2):99-10

Accreditation Handbook

This handbook is a reference for the faculty, academic and administrative staff on the process and procedure involved in preparing and obtaining accreditation. This handbook also serves as a valuable guide for the faculty to develop an assessment plan in the process of the future accreditation