Correlation between Grades in the Medical Basic Science Course and Scores on the Comprehensive Basic Sciences Exam in Iran

Introduction: Medical students in Iran are required to undertake a Basic Sciences Comprehensive Exam (BSCE) at the end of their BS course in order to progress to the next stage of medical education. BSCE results are widely used to evaluate medical education programs among different medical universities. The aim of this study is to explore the correlation between BSCE results and students’ mean BS course scores.Methods: A cross-sectional study, using secondary data analysis, was carried out in 2007 in Hormozgan University of Medical Sciences (HUMS) in Iran. Data from the 20th BSCE (held in 1998) to the 36th BSCE (held in 2006) was collected. All medical students who took these exams and for whom the mean results of the BS course and the BSCE were available were eligible for inclusion in the study. For each medical student, data were obtained regarding age at the time of participation in BSCE, together with sex, entrance year, zone as categorised by the national quota system, mean BS course scores, BSCE result, duration of BS course (number of semesters) and number of failed semesters. Students whose data was not complete were excluded from the study. Data was analysed by using SPSS 15 (SPSS Inc., Chicago, Illinois, USA) software.Results: 372 students undertook the BSCE during the research study period. Complete data was available for 365 medical students (98.1%). Among the participants, 224 (61.4%) were female and 141 (38.6%) were male. The mean age at the time of sitting the BSCE was 22.01±1.22. Mean BSCE scores were higher among students who had not previously failed a semester and who also finished the BS course within five semesters. Students with higher BS course scores had higher BSCE scores (P=0.000).Conclusions: Students’ BS course scores were found to correlate to BSCE results. Hence it may be prudent to identify medical students with low BS course scores, in order to provide additional educational support to improve their medical knowledge and thereby enhance their performance on the BSCE

Reduction of a garnieritic laterite ore by CO-CO2 gas mixtures

In extraction of nickel from laterite ores, nickel has to be reduced to metallic form in pyrometallurgical processes. This paper studied the reduction of a garnieritic laterite ore in order to establish the extents and rates of reduction of nickel, cobalt and iron oxides under different conditions, reduction mechanisms, and the optimum conditions for selective reduction of nickel and cobalt oxides over iron oxides. The reduction of the garnieritic ore was examined at 700- 900°C in the CO-CO2 gas mixtures containing 20-70 vol% CO; the gas flow rate was varied in the range of 350-1050 mL/min. A ferronickel alloy was formed by reduction of the metal oxides in the ore. The extent of reduction of nickel oxide increased with increasing temperature to 740 °C and then decreased with further increasing temperature. The extents of reduction of cobalt and iron decreased slightly with increase in temperature. Increase in CO concentration also promoted reduction of the metal oxides. When CO content was lower than 60 vol%, the extent of reduction of iron oxides was below 20%. Increase in CO concentration to 70 vol% sharply increased iron metallisation (\u3e50%). Gas flowrate above 350 mL/min had a negligible effect on the ore reduction. The effect of ore size on the reduction of the metal oxides was insignificant. The optimal conditions for selective reduction of the laterite ore included temperature 740 °Cand 60 vol% CO in the CO-CO2 gas mixture

Changes in an Australian laterite ore during heat treatment

This paper examines an Australian garnieritic-type ore and changes in phase composition and morphology caused by heating in argon at 400-1000 °C using XRF, XRD, DTA/TG, SEM/EDS and BET analyses. The mineral phases detected by XRD in the original ore include chlorite, talcum, hematite and quartz. Traces of iron silicate, Fe-Cr spinel and monoxide phase (predominantly manganese oxide) were observed by EDS. Nickel was detected in chlorite, talcum, iron silicate and monoxide phase. Heat treatment at 400-500 °C did not change XRD patterns. At 600 °C dehydroxylation of the brucitic phase of chlorite occurred. Chlorite was converted into olivine (forsterite) and enstatite at 600-800 °C. Upon heating to 900-1000 °C, talcum was also converted into olivine and enstatite. Ni-bearing phases after heat treatment at 800-850 °C were forsterite, enstatite, talcum, iron silicate and monoxide

Selective reduction of an Australian garnieritic laterite ore

Reduction of an Australian garnieritic laterite ore by different CO-CO2 gas mixtures was studied between 700 and 1000 °C. Two size ranges of the ore were examined: \u3c53 \u3eμm and 53-200 μm. Metallic nickel, cobalt, and iron in reduced garnieritic laterite samples were leached out by a Br2-CH3OH solution; their concentrations in the solution were measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis to determine reduction degree. The changes in mineral phases, morphology and the chemical composition of these phases in the reduced ore were examined by XRD and SEM/EDS. It is confirmed that in this ore, nickel occurs with magnesium and iron as silicate isomorphisms including chlorite, talc and their derivative phases/particles (olivine and pyroxene). The BSE micrographs at high magnifications found Fe-Ni alloy was formed during reduction and its grains dispersed within silicate particles. The morphological and compositional observations indicate that numerous pores and cracks were generated in dehydroxylated chlorite, talc, and pyroxene particles, making nickel readily attacked by gases. Dense structures, however, were formed for olivine particles, rendering nickel inside difficult to reduce. Current study suggests that reduction temperature and reducing gas compositions are key factors for selective reduction. The optimal conditions for nickel and cobalt production from this garnieritic laterite by selective reduction can be mediated at 740 °C in 60% CO, at which satisfactory metallisation of 91% Ni and 94% Co in the particles \u3c53 \u3eμm and 85% Ni and 99% Co in the particles 53-200 μm but less than 20% Fe were achieved

Reducing net CO2 emissions using charcoal as a blast furnace tuyere injectant

The replacement of coal-based fuels by renewable fuels such as charcoal is an attractive way to reduce net greenhouse gas emissions from the integrated steelmaking route. Our previous studies have indicated that the potential for savings in net CO2 emissions ranges from 32 to 58 percent, with use as a BF tuyere injectant being the largest application. The current study considered the combustibility of four types of charcoal in comparison with PCI coal under simulated BF raceway conditions. The major findings were that burnouts under standard conditions (air-cooled coaxial lance, O/C = 2.0) were comparable or better than that of the high volatile matter PCI coal studied, and a comparison with the trend line for burnout with injectant volatile matter previously established for coals, indicated that the hardwood charcoals studied had burnouts 40% (abs) higher than those of equivalent coals, and the softwood charcoal studied was higher again. A study of the effects of oxygen enrichment indicated that small increases were effective, and particularly so for the least combustible charcoal. Overall, the burnout results indicated that higherthan- coal injection rates should be possible in industrial practice, and in combination with the previous heat and mass balance results, they indicated the potential for increased BF productivity. The brief study of the combustion of coal-charcoal mixtures indicated good combustibility and predictable burnouts. The microscopic examination of both the charcoal injectants and their combustion chars indicated that there was significant fragmentation of the charcoals during combustion, boosting their already high surface areas and combustibility

Development of Low-Emission Integrated Steelmaking Process

This paper provides a summary of the progress made over the 8 years of an R&D program that focused on the development of know-how and processes that could result in substantial reduction in net CO2 emission by the steel industry. The processes that were developed covered introduction of renewable carbon and energy sources as well as minimising waste heat from processes. The current status of each of the processes and application areas is provided. The use of biomass-derived fuels and reductants in the ironmaking and steelmaking industry provides a sustainable option for reducing net CO2 emissions at a lower capital cost and technological risk than other breakthrough technologies under development. A key focus of this program has been to partially substitute these fossil-based fuels with renewable carbon (charcoal) from sustainable sources such as plantations of biomass species or forest wastes. Raw biomass is unsuitable for applications in ironmaking and steelmaking and should be converted into charcoal (char) through a pyrolysis process before use. A new pyrolysis process which operates continuously and autogenously has been developed and piloted. The biomass-derived chars and hydrocarbon fuels have great potential in lowering the net CO2 emissions of integrated (BF-BOF route) steel plants. Life cycle assessment has quantified the potential reduction in net CO2 emissions and covers cradle to gate, including plantation, harvesting, transport, pyrolysis and use of chars and bio-oil products. The properties of chars produced by biomass pyrolysis can be tailored to each of the several applications proposed (sintering solid fuel, cokemaking blend component, blast furnace tuyere injectant, liquid steel recarburiser, etc.), thus resulting in optimal performance and greater value-in-use of the char. Our economic analysis has made allowance for such value-in-use in applications, particularly as a replacement for BF pulverised coal injection. This analysis shows that key factors influencing the economics are the net cost of producing charcoal from biomass, selection of pyrolysis technology, value of the pyrolysis by-products, as well as the value-in-use for the charcoal. Dry slag granulation (DSG) has the potential to make a fundamental change in slag treatment and deliver a more sustainable alternative compared with the conventional water granulation process. The DSG process not only saves valuable water resources and reduces sulphurous emissions, but it may also recover a large amount of the high-grade heat in molten slag so to reduce greenhouse gas emission. CSIRO has been working on the development of a novel DSG process, integrated with heat recovery, since 2002 and has made significant progress in process design and optimisation based on process modelling, laboratory investigations, extensive pilot plant trials and characterisation of the solidified product granules