Development of TNB distribution network risk based asset replacement policy and guideline for medium voltage primary equipment

Asset Management (AM) is the systematic and coordinated activity of an organization to realize value from assets, through which an organization optimally and sustainably manages its assets and asset systems, their associated performance, risk and expenditures over their life cycle for the purpose of achieving its organizational strategic plan. An effective AM System enables TNB Distribution to establish and verify a holistic view of asset management throughout an asset’s whole life. It facilitates an optimal mixture of capital, operations, maintenance, resourcing, risks, performance and sustainability within a framework of good governance

Spanning trees of 2-complexes from diagram groups over the construction of semigroup presentation of integers using lifting method

For any given semigroup presentation we may obtain the fundamental group. In this paper we will determine spanning trees for the 2-complexes of the fundamental groups obtained from the union of two semigroup presentations with finite different initial generators using lifting method. The spanning trees will be systematically selected by using lifting method according to the length of words. Also the general formula for all lifts of spanning trees and the number of edges in the spanning trees will be computed

Giardia intestinalis assemblages among Egyptian symptomatic/asymptomatic cases in Cairo

Giardia intestinalis is frequent enteric protozoa, affecting humans worldwide. Human infections aremainly caused by two genetically different assemblages call A & B. This cross-sectional study characterizedthe Giardia genotypes isolated from the stool of symptomatic and asymptomatic Egyptians inCairo and correlated these genotypes with the demographic and clinical data of the cases. Stool sampleswere collected from 389 individuals (245 complaining of gastrointestinal (GIT) symptoms and144 apparently healthy asymptomatic individuals), and microscopically examined. Positive Samplesfor G. intestinalis were molecularly characterized by Copro-nPCR targeting beta-giardin gene, andthen analyzed by RFLP for assemblage identification. Giardia was detected in 62 samples (15.9%); 53samples in symptomatic cases (21.6%) and 9 samples in asymptomatic individuals (6.25%). DNA ofpositive samples was amplified by nPCR-RFLP assays. There was a significant predominance of assemblageB among symptomatic (82.7%) and asymptomatic (77.8%) groups, while the rest of sampleshad assemblage A. Among the clinical data, only flatulence was significantly associated with Giardiainfection with assemblage B. Assemblage B is the predominant genotype found in Egypt in symptomaticand asymptomatic patients suggesting an anthropologic transmission cycle.Key Words: Giardia; genotyping; Assemblage; nPCR-RFLP; beta-giardin

The influence of Sufism on Eric–Emmanuel Schmitt’s work

This paper attempts to investigate Eric-Emmanuel Schmitt(1960- ), as a Western dramatist and mystical writer of Eastern traditions through a detailed, qualitative and critical analysis of one of his most important work, Monsieur Ibrahim and the Flowers of Quran . In the play , Sufi framework and Archetypal Theory is used to present plainly and briefly the main concepts of mysticism and, at the same time, to situate mysticism within the play. Here, the author finds that the title character takes on the role of a Sufi master, initiating the protagonist, Moses, into the way of the Sufi and to eventually become his successor. The author concludes that Schmitt is indeed influenced by the master and disciple relationship in the initiation and journey of Sufism.Keywords: Modern drama, Emmanuel Schmitt, Sufism, Theater, play, Monsieur Ibrahim and the Flowers of the Qur’a

Study of Reproductive Number in SIR-SIS Model

Abstract The thresholds for mathematical epidemiology models specify the critical conditions for an epidemic to grow or die out. The reproductive number can provide significant insight into the transmission dynamics of a disease and can guide strategies to control its spread. We define the mean number of contacts, the mean duration of infection, and the mean transmission probability appropriately for certain epidemiological models, and construct a simplified formulation of the reproductive number as the product of these quantities. When the spread of the epidemic depends strongly upon the heterogeneity, and the expressions for the reproductive number become correspondingly more complex. In this article we formulate a model with different heterogeneous structures and demonstrate how to define the mean quantities for an explicit expression for the reproductive number. We derive an explicit formula for the reproductive number employing the spectral radius of the next generation operator

Interpretation of sweep frequency response analysis traces on inter-turn short circuit fault

Sweep frequency response analysis (SFRA) is a reliable method for detection and diagnosis of faults in the active part of transformers. However, although SFRA is widely employed, the interpretation of SFRA signature is still a challenge and require experts to analyse them. This is due to lack of guideline and standard for SFRA signature interpretation and clarification. This paper presents the interpretation of SFRA signature by classification and quantification on inter-turn short circuit fault on the transformer winding. The short-circuited turns fault on HV winding phase “A” was practically simulated on three different units of three-phase transformers. The results of simulated fault are presented and discussed. A conclusion was drawn which provides the interpretation of the SFRA response due to inter-turn short circuit fault case by using a statistical indicator which is NCEPRI algorithm

The effect of short circuit fault on one winding to other windings in FRA

Monitoring and diagnosis of power transformer in power systems have been examined and debated significantly in last few decades. Recently, more researchers have expressed their interest in these issues as the utilities and network operators operating under a rising cost-effecting pressure. Especially, in studying to monitor winding faults which is found to be the most common fault within transformers. This paper addresses the issue of the effect of inter-windings short circuit fault in a Dyn11 connected transformer. The specific aim is to study the effect of fault at winding of other phases to the response of measured phase. Frequency Response Analysis (FRA) which is discovered to be a powerful and sensitive method to examine and evaluate the condition, including the mechanical reliability of the transformer windings is used

The effect of short circuit fault in three-phase core-typed transformer

Different techniques for monitoring the transformer condition are continuously discussed. This is due to the fact that transformers are one of the most expensive components in the power system network. Not to mention the cost to fix any failure occurred in the transformer that have becoming more expensive nowadays. Frequency response analysis (FRA) is found to be the best method to monitor the transformer reliability. This paper presents a continuation of study presented in previous paper [1]. The study performed a laboratory test to show that the response of a normal winding phase A can be affected by short circuit fault which occurred at LV winding phase a, b, and c. To further investigate, current paper performed FRA measurement and applied fault on all phases. The same procedure is repeated on a distribution transformer to verify the findings. This is to examine the effect of fault at winding of other phases to the response of measured phase

Frequency response analysis for transformer tap changer damage detection

Frequency response analysis (FRA) method has been proven to detect the transformer winding damage. However, there is no practical study which investigates the damages on transformer tap changer even though it has a high failure rate. Hence, this paper investigates normal and faulty transformer tap changer using FRA. The FRA measurements conducted using four different test configurations. Also, normal tap changer, pitting and coking tap changer contact were investigated. In addition to FRA measurement, winding resistance measurement has been conducted. The transformer turn ratio measurement also conducted to identify the taps positions. This study results significant to understand the effect of pitting and coking tap changer on the transformer frequency response. The results showed that pitting has a slight influence on the frequency response. However, coking shows a huge variation in low-frequency response. This effect observed during the winding resistance measurement

Recurrent scrotal Arteriovenous Malformation as a Slowly Increasing Left Testicular Swelling: A case report

Arteriovenous malformations (AVMs) are benign vascular lesions. Although, the majority of AVMs occur in the central nervous system, there are published reports of AVMs involving all systems including the scrotum, kidney, and uterus. Herein we report a case of 37 years old male presented with recurrent gradual scrotal swelling for 4 years attributed to scrotal AVM. Embolization was done but one year later his symptoms reoccurred. As a result, left partial scrotal wall excision was carried out without complications. Keywords: arteriovenous malformation, AVM, scrotal swelling, scrotal malformation