Scale formation, properties and de-scaling in steelmaking

During continuous castings, reheating, and hot rolling, slab surfaces are exposed to atmospheres containing oxidizing gases which results in scale formation. Inefficient removal of the formed scale during reheating affects product surface quality. The effect of steel composition and operating parameters on scale formation and scale removal efficiencies were investigated. Experimental investigations were carried out using a thermogravimetric (TGA) apparatus designed to replicate the combustion gas atmosphere and temperature in actual industrial slab reheat furnaces. Report on oxidation kinetics, scale structure and properties, and descaling were conducted on laboratory cast and industrial samples. Different characterization techniques were used to analyze in-depth formed scale structure. Results on scale formation studies showed that sample chemistry, reheating parameters and sample surface condition significantly affected the development of scale structure and its properties particularly in the subsurface scale layer region. The studies showed that major alloying elements (Mn, Si,), micro alloying (Al) elements, and impurities (Cu, Ni, Cr) modified the properties of the formed scale and its kinetics mechanism. Complexity of scale formation due to alloying elements and impurities in steel and cast slab surface condition affected its efficient removal using hydraulic descaling. Samples with high alloying elements of Si and Mn were characterized by strong adhesion and complex root penetrations in the subsurface scale region which decreased descaling efficiency. Descaling hydraulic parameters and surface pretreatment that improved scale removal efficiency were suggested”--Abstract, page iv

An in-depth analysis of comorbidities in the context of HIV burden, in a cohort of patients seeking healthcare at Khayelitsha facilities in 2016-2017

Introduction: Improvements in early detection of human immunodeficiency virus (HIV), linkage to treatment, and availability of antiretroviral therapy (ART) have contributed to increasing life expectancy for people living with HIV (PLHIV) in South Africa. These improvements have resulted in the decline of HIV cause-specific mortalities. In addition to existing tuberculosis burden in PLHIV, cases of chronic non-communicable diseases (NCDs) are increasing in the general population. Considering the ageing population of PLHIV in South Africa, it is important to understand their health needs, as well as identify potential drivers of comorbidities that may provide avenues for future interventions. This study aimed at exploring HIV and comorbidity profiles in a virtual cohort of a population of healthcare clients accessing care in public facilities in Khayelitsha, Cape Town. Methods: Routinely collected data for healthcare clients accessing care in public facilities in 2016/17 were obtained from the Western Cape Provincial Health Data Centre, and analysed to describe ascertained comorbidities, comparing the profiles of PLHIV and HIV-negative individuals. The risks of comorbidity occurrence in PLHIV, in the context of other comorbidities and HIV metrics such as ART duration, viral load and CD4 cell counts, including the contribution of comorbidities to unsuppressed viral load levels in PLHIV were explored. Findings: The findings show that accessing HIV care may lead to earlier ascertainment of common chronic NCDs – hypertension, diabetes, chronic kidney disease (CKD), cervical cancer in PLHIV, compared to HIV-negative clients. Analysis of routine health data suggests that ascertainment of comorbidities differs for healthcare clients due to sub-population differences including age, sex, HIV status and reasons for accessing care. Routine laboratory testing results for renal function reflect distinct healthcare experiences by age for healthcare clients with and without HIV. Analysis of routine data shows that presence of an existing comorbidity may contribute to the incidence of other comorbidities and unsuppressed viral load levels in PLHIV. Conclusion: From real life routine health data, this study has explored comorbidities profiles of PLHIV and HIV-negative clients and observed that routine health data could provide a better understanding of disease profiles, healthcare access and requirements for both PLHIV and HIV-negative clients

The Factors Contributing to the Challenges with Apprenticeship in Ghana: Trainees’ Perspective

Apprenticeship has been the method of training the youth in acquiring employable skills in most developing countries. It provides an avenue for school dropouts to acquire skills leading to employment for sustainable livelihood. Apprenticeship plays a significant role in providing a skilled workforce and produces entrepreneurs, however, it is confronted with many challenges. This study, therefore, assessed the factors contributing to the challenges with an apprenticeship in Ghana, specifically from the trainees’ perspective. A descriptive survey was employed with a stratified random sampling technique used to select 1200 participants for data collection using a questionnaire. The study identified ten key or extremely challenging factors such as; the quality of the training is controlled by masters, masters provide training schedule, the training involves only practical activities, the training includes entrepreneurial skills, the training includes customer care, the training involves the use of modern technology, the training included financial management skills, there are policies governing the duration of the training, equipment and tools used are modern, and policies governing the duration training. Six components were found to be the factors contributing to the challenges, including; training structure-related factors, contemporary technological-related factors, aid-related factors, recognition-related factors, funding-related factors and perception-related factors; and these factors correlate positively and significantly. It is recommended that the government of Ghana should help in providing training structure and resources to promote skills training for the youth to acquire sustainable employment. Keywords: Apprenticeship, Apprentice, Challenges with apprenticeship, Entrepreneurs, Training DOI: 10.7176/JEP/12-30-02 Publication date:October 31st 202

Using Ant Colony Optimization on the Quadratic Assignment Problem to Achieve Low Energy Cost in Geo-distributed Data Centers

There are many problems associated with operating a data center. Some of these problems include data security, system performance, increasing infrastructure complexity, increasing storage utilization, keeping up with data growth, and increasing energy costs. Energy cost differs by location, and at most locations fluctuates over time. The rising cost of energy makes it harder for data centers to function properly and provide a good quality of service. With reduced energy cost, data centers will have longer lasting servers/equipment, higher availability of resources, better quality of service, a greener environment, and reduced service and software costs for consumers. Some of the ways that data centers have tried to using to reduce energy costs include dynamically switching on and off servers based on the number of users and some predefined conditions, the use of environmental monitoring sensors, and the use of dynamic voltage and frequency scaling (DVFS), which enables processors to run at different combinations of frequencies with voltages to reduce energy cost. This thesis presents another method by which energy cost at data centers could be reduced. This method involves the use of Ant Colony Optimization (ACO) on a Quadratic Assignment Problem (QAP) in assigning user request to servers in geo-distributed data centers.In this paper, an effort to reduce data center energy cost involves the use of front portals, which handle users� requests, were used as ants to find cost effective ways to assign users requests to a server in heterogeneous geo-distributed data centers. The simulation results indicate that the ACO for Optimal Server Activation and Task Placement algorithm reduces energy cost on a small and large number of users� requests in a geo-distributed data center and its performance increases as the input data grows. In a simulation with 3 geo-distributed data centers, and user�s resource request ranging from 25,000 to 25,000,000, the ACO algorithm was able to reduce energy cost on an average of $.70 per second. The ACO for Optimal Server Activation and Task Placement algorithm has proven to work as an alternative or improvement in reducing energy cost in geo-distributed data centers.Computer Scienc

Effect of Cu Additions on Scale Structure and Descaling Efficiency of Low C Steel Reheated in a Combustion Gas Atmosphere

Modern EAF steelmaking employs scrap as its primary source of raw material. Different sources of scrap have varying levels of residuals, which can negatively influence product properties, performance, and surface quality. The presence of some residuals, such as Cu and Ni in controlled quantities, can also positively impact steel performance for some applications. It is also well known that interactions between residuals and alloying elements in steel can modify the structure of scale formed during slab reheating prior to hot rolling. These changes in the scale structure can influence scale removability. In this study, the effect of varying Cu concentrations in a low alloyed Mn and Si containing steel was examined to investigate its impact on scale removability. Laboratory studies were performed with simulated reheating and descaling conditions that mimic the conditions used in industrial practices. The scale structure that formed during reheating in the combustion atmosphere was investigated using SEM/EDX analysis. A special laboratory water jet descaling device was used to evaluate scale removability at three different hydraulic impact factors. The results showed that Cu at different levels significantly modified scale structure that formed, particularly the internal scale layers, which affected scale removability at different applied descaling impact factors. The effects of Cu level and descaling impact factor on scale removability is discussed

The Munificent Approach in Social Science

There seems to be a growing distraction in academia which threatens the ethos of social science research. With issues of ideology, different sides dig in their heels to defend their positions often without objective consideration of the facts presented. Politicians take positions on issues that would win them points no matter the absurdity of the position. “Heroes” are defended by focusing exclusively on their “good deeds.” Though this phenomenon is on the increase in the popular media, its effects is mitigated by explanations from academics and experts, which minimize the extent to which pundits and spin doctors can distort facts. When academics too join the fray, the last vestiges that safeguards academic integrity are at risk. The tendency to consider an issue in a positive light to meet an existing expectation even in the face of evidence to the contrary is operationalized in this paper as the “Munificent Approach.” The munificent approach is based on the need to highlight the importance of an issue, institution, or a person not by an objective and systematic review and exposition of existing evidence, but on parochial or psychological grounds even in the face of overwhelming evidence to the contrary. This paradigm incorporates all the biases found in academic enterprise including ethnocentrism, Afrocentrism, Eurocentrism, and other unsystematic and non objective approaches in social science. By its parameters, the munificent paradigm will allow academics of all disciplines to be aware of unsystematic presentations and patently bias assertions and analysis, thereby safeguarding the intellectual integrity needed in all academic work. If this becomes part of undergraduate foundational work, it would ensure integrity and objectivity in students’ presentation and outlook and minimize academic and intellectual dishonesty. Keywords: Munificent, Ethnocentrism, Afrocentrism, Eurocentrism, Systemati

Effect of Cu Additions on Scale Structure and Descaling Efficiency of Low C Steel Reheated in a Combustion Gas Atmosphere

Modern EAF steelmaking employs scrap as its primary source of raw material. Different sources of scrap have varying levels of residuals, which can negatively influence product properties, performance, and surface quality. The presence of some residuals, such as Cu and Ni in controlled quantities, can also positively impact steel performance for some applications. It is also well known that interactions between residuals and alloying elements in steel can modify the structure of scale formed during slab reheating prior to hot rolling. These changes in the scale structure can influence scale removability. In this study, the effect of varying Cu concentrations in a low alloyed Mn and Si containing steel was examined to investigate its impact on scale removability. Laboratory studies were performed with simulated reheating and descaling conditions that mimic the conditions used in industrial practices. The scale structure that formed during reheating in the combustion atmosphere was investigated using SEM/EDX analysis. A special laboratory water jet descaling device was used to evaluate scale removability at three different hydraulic impact factors. The results showed that Cu at different levels significantly modified scale structure that formed, particularly the internal scale layers, which affected scale removability at different applied descaling impact factors. The effects of Cu level and descaling impact factor on scale removability is discussed

Preparedness for Use of Health Information for Planning and Decision Making: A Study of Health Facilities in the Kumasi Metropolis, Ghana

Background: Providing the right quality information system promotes effective and efficient ways of using scarce resources through proper planning and decision-making. This however depends on availability of infrastructure and adequate staff training on use of health information.Methods: This cross-sectional study was conducted among health facilities in the Kumasi metropolis and data was collected from June to September 2011. The study involved 323 health staffs, recruited from among1162 health workers from public, private, quasi and mission health facilities and the Metro Health Directorate in four of the ten sub-metros across the Kumasi metropolis. Data was analysed with STATA 11 software. Results: More than 50% had received training on HI among all the facilities. Comparatively, training on HIS was lower in the public hospitals. Training on HI and relevance the training had significant associations with the use of HI (p<0.001). Respondents who had never had training on HI were less likely to use HI for planning and decision-making as compared to those who had ever had training (OR=0.086; 95% CI=0.03, 0.25). Although most facilities had available logistics for storage, processing and using health information, not all were functioning. Challenges associated with use of HI included inaccurate data, low knowledge on IT, unreliable information, inconsistent data, improper documentation and power cut offs. Conclusion: Use of health information remains critical to making evidenced based decision-making. Improving health training and the requisite logistics could improve use of HI among health staffs. Keywords: health information, planning, Kumasi metropolis, training, logistics, preparednes

Evaluation of Nutritional Quality of Dried Cashew Nut Testa Using Laboratory Rat as a Model for Pigs

Dried cashew nut testa (DCNT) was characterized with respect to proximate, mineral, and energy profile. The crude protein, crude fibre, and fat and ash contents were, in g kg−1 DM, 190.0, 103.0, 20.1, and 20.2, respectively, with metabolizable energy of 7.12 MJ kg−1 DM. In a feeding trial, isoproteic diets containing DCNT (O, 50, 100, and 150 g kg−1) were fed ad libitum to 4 groups of Sprague-Dawley male rats (110 g body weight, n = 20) for a period of 4 weeks. The rats, used as model for pigs, had free access to water. As the dietary DCNT content was increased from 0 to 150 g kg−1, there was a significant (P < 0.01) decrease in feed intake (r = −0.99), water intake (r = −0.87), and a reduction in body weight gain (r = −0.93) and efficiency of feed utilization (r = 0.78). However, no deaths or health-related problems were recorded during the study. Dietary treatments had no impact on liver, heart, lungs, kidneys, and intestinal weights. Cost per gram feed and feed cost per gram live weight gain were reduced when DCNT was used. The experimental diet containing 50 g DCNT kg−1 supported the best growth performance with the lowest feed cost per gram live weight gain of GHȼ0.18. Seasonal increases in the prices of conventional feedstuffs like maize and fishmeal would make the use of agroindustrial by-products such as DCNT in pig diets even more attractive

Magnitude and trend of HIV and Treponema pallidum infections among blood donors in Offinso-North District, Ghana: a nine-year retrospective, cross-sectional study

Introduction: Blood transfusion poses a high public health risk to recipients; hence no effort recommended to eradicate or minimize the danger of transmitting the infections.bReproductive Biology should be underestimated at minimizing the risk of TTIs. This study determined the prevalence and trend of HIV and syphilis infections in voluntary blood donors. Method: A retrospective analysis of secondary data from consecutive prospective voluntary blood donors who accessed Nkenkaasu District Hospital’s Blood Bank from January 2010 to December 2018 was conducted. Result: Cumulatively, HIV and Treponema pallidum seropositivity identified in the present study was high (19.1%, [95% C.I (0.026-0.028)]) . The prevalence of HIV and syphilis infections were 10.9% (95% C.I (0.098-0.120)) and 8.9% (95% C.I (0.073-0.92)) respectively. Prospective female blood donors were less likely to test positive for T. pallidum than males (OR 0.511, [0.340 – 0.769], p=0.001), but the infection was similar among different ages. The data showed downward trend for both HIV and T. pallidum seropositivity, (slope=-2.9467, p&lt;0.0001) and (slope=-0.7117, p&lt;0.0001) respectively. Conclusion: Seroprevalence of HIV and Treponema pallidum were high, and their individual or combined seropositivity pose a significant threat to the safety of blood. Extensive and continuous screening for high-risk behaviours and infectious markers before blood donation is therefore Unit, Department of Obstetrics and Gynaecology, College of Medicine, Pan African University of Life and Earth Sciences Institute (PAULESI), University of Ibadan, Ibadan, Nigeria. Keywords: Blood donors; HIV; magnitude; trend; Treponema pallidum