The Experts below are selected from a list of 35013 Experts worldwide ranked by ideXlab platform
Guillermo Rios - One of the best experts on this subject based on the ideXlab platform.
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post mortem study of magnesia chromite refractory used in a submerged arc furnace in the copper making process
JOM, 2018Co-Authors: Ismael Perez, I Morenoventas, Roberto Parra, Guillermo RiosAbstract:The periodical relining of furnaces because of refractory wear is a Cost Driver in the copper-making industry. This paper presents a post-mortem study of the refractory lining of a submerged arc furnace used in slag-cleaning operations at the Atlantic Copper Smelter (Spain) after a 6-year campaign. Samples were taken from different locations in the area in contact with slag and analyzed using a scanning electron microscope equipped with an energy dispersive spectroscopy system. New phases were generated as a consequence of the chemical interaction between the molten slag in the bath and the magnesia–chromite refractory lining. The chemical dissolution of the magnesia of the refractory and the incorporation of iron from the slag in the refractory phases were the main Drivers. From this interaction, a reaction layer on the hot face of the refractory was formed, whose properties differ from the as-delivered refractory.
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Chemical degradation of magnesia-chromite refractory used in the conversion step of the pyrometallurgical copper-making process: A thermochemical approach
Ceramics International, 2018Co-Authors: Ismael Perez, Ignacio Moreno-ventas, Guillermo RiosAbstract:Abstract Refractory wear in furnaces is a key Cost Driver in pyrometallurgical processes, leading to periodical relining that involves maintenance and increased operational Costs. One of the main factors in refractory wear is the chemical attack by the molten phases from the bath. This chemical interaction generates new phases in the refractory, producing different properties and causing spallation due to the aggregate effect of the thermal and mechanical shocks during operation. This paper uses thermodynamic databases (Fact Sage® software) to study the interaction between the molten phases and the magnesia-chromite refractory in the conversion step of the copper-making process. Input data were taken from an industrial furnace at Atlantic Copper S.L.U. (Huelva, Spain) and the calculations were conducted at different temperatures and oxygen partial pressures (pO2). These thermochemical calculations allow the chemical degradation of the refractory to be evaluated. The results show the characterization of the new phases (mainly spinel and olivine) formed after the chemical interaction between the molten phases and the refractory. Since the composition and mass distribution of the new phases change, the degree of refractory wear is calculated for each scenario designed.
Miguelangel Sicilia - One of the best experts on this subject based on the ideXlab platform.
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enhancing input value selection in parametric software Cost estimation models through second level Cost Drivers
Software Quality Journal, 2006Co-Authors: Juan J Cuadradogallego, Luis Fernandezsanz, Miguelangel SiciliaAbstract:Parametric Cost estimation models are widely used effort prediction tools for software development projects. These models are based on mathematical models that use as inputs specific values for relevant Cost Drivers. The selection of these inputs is, in many cases, driven by public prescriptive rules that determine the selection of the values. Nonetheless, such selection may in some cases be restrictive and somewhat contradictory with empirical evidence, in other cases the selection procedure is somewhat subject to ambiguity. This paper presents an approach to improve the quality of the selection of adequate Cost Driver values in parametric models through a process of adjustment to bodies of empirical evidence. The approach has two essential elements. Firstly, it proceeds by analyzing the diverse factors potentially affecting the values a Cost Driver input might adopt for a given project. And secondly, an aggregation mechanism device for the selection of input variables based on existing data is explicitly devised. This paper describes the rationale for the overall approach and provides evidence of its appropriateness through a concrete empirical study that analyses the COCOMO II DOCU Cost Driver.
Van Isabelle Gelder - One of the best experts on this subject based on the ideXlab platform.
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the Cost of illness of atrial fibrillation a systematic review of the recent literature
Europace, 2011Co-Authors: S E Wolowacz, M Samuel, Victoria K Brennan, J G Jassomosqueda, Van Isabelle GelderAbstract:Atrial fibrillation (AF) is the most common cardiac arrhythmia, its prevalence increasing markedly with age. Atrial fibrillation is strongly associated with increased risk of morbidity, including stroke and thromboembolism. There is growing awareness of the economic burden of AF due to ageing populations and constrained public finances. A systematic review was performed (1990-2009). Cost studies for AF or atrial flutter were included; acute-onset and post-operative AF were excluded. Total, direct, and indirect Costs were extracted. Of 875 records retrieved, 37 studies were included. The Cost of managing individual AF patients is high. Direct-Cost estimates ranged from $2000 to 14,200 per patient-year in the USA and from €450 to 3000 in Europe. This is comparable with other chronic conditions such as diabetes. The direct Cost of AF represented 0.9-2.4% of the UK health-care budget in 2000 and had almost doubled over the previous 5 years. Inpatient care accounted for 50-70% of annual direct Costs. In the USA, AF hospitalizations alone Cost ∼$6.65 billion in 2005. In this first systematic review of the economic burden of AF, hospitalizations consistently represented the major Cost Driver. Costs and hospitalizations attributable to AF have increased markedly over recent decades and are expected to increase in future due to ageing populations.
Sungsig Bang - One of the best experts on this subject based on the ideXlab platform.
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break even point analysis of sodium cooled fast reactor capital investment Cost comparing the direct disposal option and pyro sodium cooled fast reactor nuclear fuel cycle option in korea
Sustainability, 2017Co-Authors: Hong Jang, Yanghon Chung, Sungsig BangAbstract:The purpose of this paper is to recommend a break-even point for the capital investment Cost for a Sodium-cooled Fast Reactor (SFR) when choosing between a Pyro-SFR nuclear fuel cycle (recycling option via Pyro-processing) and a direct disposal option. This is because the selection of an alternative cannot be justified without a guarantee of economic feasibility. The calculation of a break-even point is necessary because SFR capital investment Cost makes up the largest share of the Cost for electricity generation. In other words, the Cost of capital investment is an important Cost Driver, and the one that exerts the greatest effect on Pyro-SFR nuclear fuel cycle economics. In the end, the break-even point of the SFR capital investment Cost between the Pyro-SFR nuclear fuel cycle and the direct disposal was calculated to be 4284 US$/kWe. In other words, it is possible to claim that the potential for the economic viability of the Pyro-SFR nuclear fuel cycle is greater (compared to investing in direct disposal) when the SFR capital investment Cost is 4284 US$/kWe or less. In addition, Pyro-SFR technology will enable sustainable nuclear power generation.
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Statistical model for forecasting uranium prices to estimate the nuclear fuel cycle Cost
Nuclear Engineering and Technology, 2017Co-Authors: W I Ko, Yanghon Chung, Sungsig BangAbstract:Abstract This paper presents a method for forecasting future uranium prices that is used as input data to calculate the uranium Cost, which is a rational key Cost Driver of the nuclear fuel cycle Cost. In other words, the statistical autoregressive integrated moving average (ARIMA) model and existing engineering Cost estimation method, the so-called escalation rate model, were subjected to a comparative analysis. When the uranium price was forecasted in 2015, the margin of error of the ARIMA model forecasting was calculated and found to be 5.4%, whereas the escalation rate model was found to have a margin of error of 7.32%. Thus, it was verified that the ARIMA model is more suitable than the escalation rate model at decreasing uncertainty in nuclear fuel cycle Cost calculation.
Ismael Perez - One of the best experts on this subject based on the ideXlab platform.
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post mortem study of magnesia chromite refractory used in a submerged arc furnace in the copper making process
JOM, 2018Co-Authors: Ismael Perez, I Morenoventas, Roberto Parra, Guillermo RiosAbstract:The periodical relining of furnaces because of refractory wear is a Cost Driver in the copper-making industry. This paper presents a post-mortem study of the refractory lining of a submerged arc furnace used in slag-cleaning operations at the Atlantic Copper Smelter (Spain) after a 6-year campaign. Samples were taken from different locations in the area in contact with slag and analyzed using a scanning electron microscope equipped with an energy dispersive spectroscopy system. New phases were generated as a consequence of the chemical interaction between the molten slag in the bath and the magnesia–chromite refractory lining. The chemical dissolution of the magnesia of the refractory and the incorporation of iron from the slag in the refractory phases were the main Drivers. From this interaction, a reaction layer on the hot face of the refractory was formed, whose properties differ from the as-delivered refractory.
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Chemical degradation of magnesia-chromite refractory used in the conversion step of the pyrometallurgical copper-making process: A thermochemical approach
Ceramics International, 2018Co-Authors: Ismael Perez, Ignacio Moreno-ventas, Guillermo RiosAbstract:Abstract Refractory wear in furnaces is a key Cost Driver in pyrometallurgical processes, leading to periodical relining that involves maintenance and increased operational Costs. One of the main factors in refractory wear is the chemical attack by the molten phases from the bath. This chemical interaction generates new phases in the refractory, producing different properties and causing spallation due to the aggregate effect of the thermal and mechanical shocks during operation. This paper uses thermodynamic databases (Fact Sage® software) to study the interaction between the molten phases and the magnesia-chromite refractory in the conversion step of the copper-making process. Input data were taken from an industrial furnace at Atlantic Copper S.L.U. (Huelva, Spain) and the calculations were conducted at different temperatures and oxygen partial pressures (pO2). These thermochemical calculations allow the chemical degradation of the refractory to be evaluated. The results show the characterization of the new phases (mainly spinel and olivine) formed after the chemical interaction between the molten phases and the refractory. Since the composition and mass distribution of the new phases change, the degree of refractory wear is calculated for each scenario designed.
