A Critical Review of Distribution Substation System Reliability Evaluations

The significance of a reliable distribution system is hinged on the fact that even if the generation and transmission of a power system are highly reliable, an unreliable distribution system will mean that there will be poor supply of energy to the consumers. Therefore, there must be ways of measuring the reliability of power distribution systems according to given standards in order to help inform the system engineers on the causes of interruptions. This will in turn help in proffering methods of accomplishing a more reliable distribution system. There are established basic methods of assessing the reliability of this system and different researchers engage the one best suited for the analysis they intend to carry out. Moreover, going through previous published works on distribution system reliability evaluation, insight is given into why a distribution behaves below standard and how it could be possibly improved. This paper presents an overview of the basic methods used in reliability assessment with the frequently used reliability indices and a critical review of published works by authors in carrying out the reliability evaluation of different power distribution systems based on these various methods

Reliability Analysis of Secondary Distribution System in Nigeria: A Case Study of Ayetoro 1 Substation, Lagos State.

A power system is set up basically to meet the demands of the customers. However, interruptions which are largely unavoidable contribute to the unavailability of power and thus prevent power system from achieving this. In most cases, it is the sustained interruptions that greatly affect both the utility company and its customers. Hence, it is necessary to find means of determining which component failure contributes most to the unavailability of the distribution system, and how this unavailability actually affects the customers. This is to enable system planners and designers to seek better ways of improving the reliability of a typical secondary distribution substation system having a single-end fed radial configuration. By using analytical method and network reduction technique, the substation reliability was analyzed based on the outage data gotten from the utility company. The conclusion from this work shows that transformer failure followed by fuse failure contributes most to the substation’s unavailability. The overall system availability shows that the system’s performance is poor

Human Security and Developmental Crisis in the Contemporary West Africa

The last two decades were characterized by severe conflicts in the West Africa subregion. The era of conflict resolution, management and peace building thus came to define theregion. The destruction left by long years of protracted conflicts and the present state of devel opment is reason enough to warrant attention both from within and beyond. The study expounds, operationalizes and clarifies the concept of human security and development, and how human security issues lead to underdevelopment. The paper investigates the human security concerns in the post-conflict period and also looks at the crisis of development in the sub-region. It highlights details on the developmental crises that have bedevilled the sub-region and at the same time exposes the threats these crises pose on national security and peace in the subregion. This paper concludes that there is no appreciable effort in operationalizing human security in West Africa and this will lead to instability. The paper maintains that human security issues now complicate the developmental crisis in the sub-region due to its ambiguity. The paper suggests that policy makers should address human security issues in order to tackle developmental crisis in the sub-region

Human Security and Developmental Crisis in the Contemporary West Africa

The last two decades were characterized by severe conflicts in the West Africa subregion. The era of conflict resolution, management and peace building thus came to define theregion. The destruction left by long years of protracted conflicts and the present state of devel opment is reason enough to warrant attention both from within and beyond. The study expounds, operationalizes and clarifies the concept of human security and development, and how human security issues lead to underdevelopment. The paper investigates the human security concerns in the post-conflict period and also looks at the crisis of development in the sub-region. It highlights details on the developmental crises that have bedevilled the sub-region and at the same time exposes the threats these crises pose on national security and peace in the subregion. This paper concludes that there is no appreciable effort in operationalizing human security in West Africa and this will lead to instability. The paper maintains that human security issues now complicate the developmental crisis in the sub-region due to its ambiguity. The paper suggests that policy makers should address human security issues in order to tackle developmental crisis in the sub-region

Analysis of the hippocampal proteome in ME7 prion disease reveals a predominant astrocytic signature and highlights the brain-restricted production of clusterin in chronic neurodegeneration

Prion diseases are characterized by accumulation of misfolded protein, gliosis, synaptic dysfunction, and ultimately neuronal loss. This sequence, mirroring key features of Alzheimer disease, is modeled well in ME7 prion disease. We used iTRAQ(TM)/mass spectrometry to compare the hippocampal proteome in control and late-stage ME7 animals. The observed changes associated with reactive glia highlighted some specific proteins that dominate the proteome in late-stage disease. Four of the up-regulated proteins (GFAP, high affinity glutamate transporter (EAAT-2), apo-J (Clusterin), and peroxiredoxin-6) are selectively expressed in astrocytes, but astrocyte proliferation does not contribute to their up-regulation. The known functional role of these proteins suggests this response acts against protein misfolding, excitotoxicity, and neurotoxic reactive oxygen species. A recent convergence of genome-wide association studies and the peripheral measurement of circulating levels of acute phase proteins have focused attention on Clusterin as a modifier of late-stage Alzheimer disease and a biomarker for advanced neurodegeneration. Since ME7 animals allow independent measurement of acute phase proteins in the brain and circulation, we extended our investigation to address whether changes in the brain proteome are detectable in blood. We found no difference in the circulating levels of Clusterin in late-stage prion disease when animals will show behavioral decline, accumulation of misfolded protein, and dramatic synaptic and neuronal loss. This does not preclude an important role of Clusterin in late-stage disease, but it cautions against the assumption that brain levels provide a surrogate peripheral measure for the progression of brain degeneration

Perinatal outcome in anaemic pregnant women in South-Western Nigeria

Background: Anaemia in pregnancy is a global public health problem in most developing and developed countries with major consequences for human health as well as social and economic development. Fetuses of anaemic mothers are at risk of preterm deliveries, low birth weights, morbidity and perinatal mortality due to the impairment of oxygen delivery to placenta and foetus.Methods: This study was conducted at the antenatal clinic and labour ward complex of a teaching hospital in south-western Nigeria to determine the effect of anaemia in pregnancy on perinatal outcome. Eligible participants were enrolled for the study by consecutive sampling method. Relevant data were extracted from the case records of these eligible women and a structured interviewer administered questionnaire was used for the data collection.Results: There were statistically significant differences between anaemia and reduced gestational age at birth (P = 0.000), low one-minute (P = 0.000) and five-minute (P = 0.003) Apgar scores, reduced birth weight (P=0.005) and foetal death (P = 0.013). No significant difference was noted in the rate of neonatal admission in the two groups (P = 0.085).Conclusion: This study has thus highlighted the importance of considering maternal anaemia as an indicator of adverse perinatal outcomes. There is therefore, a need to counsel intending mothers and their partners about early antenatal booking, compliance with routine antenatal medications and prompt identification and treatment of anaemia in pregnancy, all as means of curtailing the overwhelming perinatal morbidity and mortality associated with the condition.

Preterm delivery and low maternal serum cholesterol level: any correlation?

Background: Preterm birth is a major challenge in perinatal health care with prematurity accounting for 40-60% of all perinatal deaths in Nigeria. The physiologic hypercholesterolaemia of later pregnancy suggests an adaptive function for pregnancy maintenance or fetal growth. Decreased levels of maternal total cholesterol and low-density lipoprotein cholesterol have been reported in association with preterm delivery.Methods: This was a prospective observational cohort study designed to assess whether low maternal serum cholesterol during early pregnancy is associated with preterm delivery in these women. Eligible participants were enrolled for the study at gestational age of 14 to 20 weeks over a period of 12 months. Blood samples were obtained to measure total serum cholesterol concentrations and the sera were then analyzed enzymatically by the Cholesterol Oxidase: p-Aminophenazone (CHOD PAP) method.Results: The study showed an incidence of 5.0% for preterm delivery in the low risk study patients. Preterm birth was 4.83-times more common with low total maternal cholesterol than with midrange total cholesterol (11.8% versus 2.2%, P = 0.024).Conclusions: We can infer from the study that the low maternal serum cholesterol (hypocholesterolaemia) is associated with preterm delivery. We can therefore recommend on this basis that the concept of an optimal range for maternal serum cholesterol during pregnancy may have merit and pregnant women should be encouraged to follow a healthy, balanced diet and ensure regular antenatal visit to their healthcare provider