POWER SYSTEMS OPERATION IMPROVEMENT CONSIDERING LOSS MINIMIZATION AND VOLTAGE STABILITY ENHANCEMENT

The challenge of energy and power losses during electrical energy transmission from generation plants to users is a major problem that cannot be over-emphasized. These Losses are inevitable because they are inherent in the conduction of electrical energy through physical means but can be minimized. This paper presents a VSC-PSO method for optimizing the power system operation by simultaneously minimizing the loss and enhancing the voltage stability which are the objective functions. The optimal power flow (OPF) was performed on IEEE 30-bus system with Newton Raphson algorithm implemented in MATLAB simulation software. The simulation results showed that the VSC-PSO approach performed more excellently with concurrent consideration of line loss reduction and voltage stability improvement when compared with other methods in literatur

Climate change effects on people’s livelihood

Generally climate is defined as the long-term average weather conditions of a particular place, region, or the world. Key climate variables include surface conditions such as temperature, precipitation, and wind. The Intergovernmental Panel on Climate Change (IPCC) broadly defined climate change as any change in the state of climate which persists for extended periods, usually for decades or longer (Allwood et al. 2014). Climate change may occur due to nature’s both internal and external processes. External process involves anthropogenic emission of greenhouse gases to the atmosphere, and volcanic eruptions. The United Nations Framework Convention on Climate Change (UNFCCC) made a distinction between climate change attributable to human contribution to atmospheric composition and natural climate variability. In its Article 1, the UNFCCC defines climate change as “a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods” (United Nations 1992, p. 7)

Peripheral False Aneurysms: An Evolution Of Precedent Vascular Injury

With the rise in armed conflicts in Nigeria, major vascular injuries are seen more commonly. Unfortunately it is not well appreciated that securing haemostasis at the site of injury is not tantamount to adequate handling of the vascular situation. Occasioned by misdiagnosis of the extent and type of vascular damage, false aneurysms may develop long after the initial care of the damaged vessel. Presented here are eleven consecutive cases of peripheral false aneurysms of the extremities which developed between two weeks and nine months after the initial injury. Objective evaluation and prompt referral to vascular surgical units will improve the management of such cases and so obviate the development of false aneurysms. Keywords: False, Aneurysm, PromptNigerian Journal of Surgical Sciences Vol. 17 (2) 2007: pp. 109-11

Corporate board characteristics and environmental disclosure quantity: Evidence from South Africa (integrated reporting) and Nigeria (traditional reporting)

The study examined the influence of corporate board characteristics on environmental disclosure quantity of listed firms in two leading emerging economies: South Africa and Nigeria which practice integrated reporting framework and traditional reporting framework, respectively. Two issues motivate the study: First, calls by researchers for integrated reporting regulation in Nigeria. Second, the challenge facing regulatory bodies and companies boards in Nigeria in ensuring commitment to the protection of the environment and the society. Many studies have examined the influence of corporate governance on environmental disclosure at the cross-country level, documenting evidence that corporate governance mechanisms are essential for corporate ecological reporting. However, these studies examined settings based on the legal framework and mostly focused on companies quoted on common and civil law countries. They neglected the weak and robust reporting framework and difference within either common or civil law countries. Our study provides evidence on corporate board characteristics influence on environmental disclosure of quoted firms in South Africa and Nigeria. Data obtained from annual reports of 303 environmentally sensitive companies selected from South Africa (213) and Nigeria (90) was investigated using descriptive, multivariate, and regression model. Major findings indicate a significant positive association between board independence and environmental disclosure in Nigeria. In South Africa, 45% of environmentally sensitive industries significantly influence environmental disclosure, while 51% of environmentally polluting industries in Nigeria show insignificant association with environmental disclosure. Our findings are helpful to policymakers and other regulators for an impactful framework on environmental reporting

Effect of international financial reporting standard (IFRS) adoption on earnings value relevance of quoted Nigerian firms

In this study, we examine the effect of IFRS adoption on the earnings value relevance of quoted Nigerian firms. Using a sample of 101 firms (1212 firms-year observation) that are quoted on or before 2006, and have adopted IFRS from 2006 to 2017, we can investigate earnings value relevance. As the principal objective of the inquiry, we introduce a cross-product term, equal to the product of earnings per share (EPS) and IFRS dummy variable, into the basic Ohlson model. The paper uses the Fixed Effect Model as the appropriate estimator for analysis of the data. The estimated coefficient on the cross-product term is statistically significant and positive. The results suggest that the adoption of IFRS in Nigeria leads to higher earnings value relevance. IFRS, as a principle-based, allows managers to use their discretion in the specific treatment of financial items. In doing so, they may bias earnings. Further, the results revealed that estimated coefficient of the cross product of book value and IFRS dummy variable is statistically insignificant and negative. Surprisingly, the simultaneous addition of earnings, the book value of equity, and firm-specific variables in a modified basic Ohlson model show enhanced earning incremental value relevance, while other variables were insignificant, except the interaction of earnings and audit firm size. Overall, results suggest that earnings under IFRS are valued relevance about economic growth conditions, with the nature of such relevance explaining variations on the share price. The findings of this study are utmost important to economic policymakers, investors, and Standard Setters

Wound dressing where there is limitation of choice

Background Many sophisticated dressings are available to the wound care practitioner in the developed countries. These materials are made from a wide range of products like polyurethane, salts of alginic acid and other gelable polysaccharides. The situation is different in the developing countries where what is commonly available to wound care provider are traditional agents such as sodium hypochlorite, hydrogen-peroxide, cetrimide solution, chlorhexidine and others. The aim of this study is to reappraise the problem of limitation of wound dressing selection in the developing countries and to sensitize the wound care practitioner on the use of the commonly available products based on the needs of a different wound or even the same wound throughout its healing course. Patients and methods Patients attending the General Outpatient Department (GOPD) of our hospital for wound dressing were used for the study. Five surgeons who are familiar with wound care management visited the dressing unit of the GOPD daily for one week in October 2005. A proforma was designed where information on each of the patient was recorded. Results Fifty-three patients attended the dressing unit of our GOPD during the study period. Twenty-six patients (49.1%) had their wounds dressed with hypochlorite solution (Eusol), seventeen patients (32.1%) had their wounds dressed with honey and two patients, wound were being dressed with hydrogen peroxide. Conclusion While we are still awaiting the availability of the newer products in the developing countries, we should make use of the traditional products that are readily available to us according to the need of a particular wound, by this, our choice of wound dressing will not be arbitrary, ineffective and wasteful both in terms of time and physical resources

Corrosion inhibition of copper in aqueous chloride solution by 1H-1,2,3-triazole and 1,2,4-triazole and their combinations: electrochemical, Raman and theoretical studies

Triazoles are well-known organic corrosion inhibitors of copper. 1H-1,2,3-Triazole and 1,2,4-triazole, two very simple molecules with the only difference being the positions of the nitrogen atoms in the triazole ring, were studied in this work as corrosion inhibitors of copper in 50 mM NaCl solution using a set of electrochemical and analytical techniques. The results of electrochemical tests indicate that 1H-1,2,3-triazole exhibited superior inhibitor properties but could not suppress anodic copper dissolution at moderate anodic potentials (4+300 mV SCE), while 1,2,4-triazole, although it exhibited higher anodic currents, suppressed anodic copper dissolution at very anodic potentials. Density functional theory calculations were also performed to interpret the measured data and trends observed in the electrochemical studies. The computational studies considered either the inhibitors isolated in the gaseous phase or adsorbed onto Cu(111) surface models. From the calculations, the mechanisms of the inhibitive effects of both triazoles were established and plausible mechanisms of formation of the protective films on the Cu surface were proposed. The results of this study hold positive implications for research in the areas of catalysis, and copper content control in water purification systems.This work was developed in the scope of the project CICECO – Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. Financed in the framework of project reference PTDC/QEQ-QFI/4719/2014, funded by Project 3599 - Promover a Produção Científica e Desenvolvimento Tecnológico e a Constituição de Redes Temáticas (3599-PPCDT) and FEDER funds through COMPETE 2020, Programa Operacional Competitividade e Internacionalização (POCI). The authors also thank financial support from FCT and COMPETE (PTDC/CTM-MAT/1515/2012 and Programa Investigador FCT). JT thanks FCT for the research grant IF/00347/2013. This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreements No 645662 and No 645676. This work has also received funding from the European Union’s Seventh Framework Programme (FP7/2012-2016) under the grant agreement no. 280759.publishe