Ferrosilicon production method using sintered iron silicate - fayalite

The study aims experimentally investigate how to obtain a ferrosilicon alloy using iron silicate - fayalite generated after flotation enrichment of slag in pyrometallurgical production of copper. This material contains about 46 % iron and about 27 % silicon dioxide. Due to its dispersed structure, fayalite is first sintered. The article describes mathematical and physical modeling of the agglomeration and ore thermal process for the production of ferrosilicon. The main fraction of the obtained agglomerate (57,60 %) is over 15 mm. In the electric arc furnace, the time for refining the agglomerate tap to tap is 40 - 60 minutes. The obtained alloy yield is 46 %. In the three melts, the silicon content in the alloy averaged 44 %, meeting the ferrosilicon standard

Ferrosilicon production method using sintered iron silicate - fayalite

The study aims experimentally investigate how to obtain a ferrosilicon alloy using iron silicate - fayalite generated after flotation enrichment of slag in pyrometallurgical production of copper. This material contains about 46 % iron and about 27 % silicon dioxide. Due to its dispersed structure, fayalite is first sintered. The article describes mathematical and physical modeling of the agglomeration and ore thermal process for the production of ferrosilicon. The main fraction of the obtained agglomerate (57,60 %) is over 15 mm. In the electric arc furnace, the time for refining the agglomerate tap to tap is 40 - 60 minutes. The obtained alloy yield is 46 %. In the three melts, the silicon content in the alloy averaged 44 %, meeting the ferrosilicon standard

Thermodynamic and kinetic investigation of carbothermic reduction of electric arc furnace dust

The thermodynamics and kinetics of electric arc furnace dust (EAFD) reduction were studied experimentally. The oxygen potential in the systems was determined by the electromotive force (EMF) method. Experimental equations for ΔG = f(T) were derived. The CO content at different temperatures was determined. The highest degree of reduction was observed at the ratio EAFD/reducing agent - 1:2 at a temperature of 1 173 K. The changes in the mass during heating, the rate of the processes, and the reduction degree were mathematically modeled. The activation energy is 74,7 kJ/mol for EAFD: reducing agent 1:1 and increased to 95,2 kJ/mol for the ratio EAFD: reducing agent 1:2,5. Analysis of the reaction kinetics showed that the reduction process was mostly chemical кinetics controlled

Thermodynamic and kinetic investigation of carbothermic reduction of electric arc furnace dust

The thermodynamics and kinetics of electric arc furnace dust (EAFD) reduction were studied experimentally. The oxygen potential in the systems was determined by the electromotive force (EMF) method. Experimental equations for ΔG = f(T) were derived. The CO content at different temperatures was determined. The highest degree of reduction was observed at the ratio EAFD/reducing agent - 1:2 at a temperature of 1 173 K. The changes in the mass during heating, the rate of the processes, and the reduction degree were mathematically modeled. The activation energy is 74,7 kJ/mol for EAFD: reducing agent 1:1 and increased to 95,2 kJ/mol for the ratio EAFD: reducing agent 1:2,5. Analysis of the reaction kinetics showed that the reduction process was mostly chemical кinetics controlled

MEDICAL INFORMATION CENTRE, BULGARIAN CITATION INDEX, AND MODERN BULGARIAN SCIENCE. I. BULGARIAN MEDICAL JOURNALS (1993-1998)

The Medical Information Centre of Sofia is an established prestigeous institution of rising national and international importance for the medical sciences and public health. The present communication initiates a series of scientometric investigations using the Bulgarian Citation Index (BCI) data-base of the communication patterns in different branches of modern Bulgarian science. The analysis of Bulgarian medical journals published in 1993-1998 shows several essential features of the citation behaviour of the authors arguing of the still insufficient awareness of the national achievements. A total of 322 issues from 47 journal titles have been already processed. They contain 2028 citing articles with a total of 26092 references. The citations to Bulgarian publications amount to 2484 or 9,5 per cent of all the citations. The following journals are most-cited in this sample: "Revmatologiya" (107 citations), Savremenna meditsina (78), "Stomatologiya" (51), "Pediatriya" and "Farmatsiya" (40 citations each)

Thermodynamic activities of V2O3, MnO, and FeO In quaternary system V2O3 - FeO - SiO2 – MnO

The activities of FeO, V2O3 and MnO in quaternary systems V2O3-FeO-SiO2-MnO have been investigated. Investigation of thermodynamic data of this slag system, aims extracting vanadium, from the waste and obtaining Mn-V alloy with potential industrial application. The oxygen potential in the systems was determined by the Electromotive force (EMF) method. The solid electrolyte was ZrO2 (CaO), and the reference electrode - a mixture of Mo/MoO2 was used as a galvanic cell. The Gibbs free energy and the activity were calculated based on experimentally obtained oxygen potential. On the basis thermodynamics of the calculations, the experimental results revealed the possibility of obtaining a complex alloy from the manganese concentrate and the vanadium waste catalyst

Haplotype Structure of FSHB, the Beta-Subunit Gene for Fertility-Associated Follicle-Stimulating Hormone: Possible Influence of Balancing Selection

Follicle-stimulating hormone (FSH) is essential for human reproduction. The unique functions of this hormone are provided by the FSH receptor-binding beta-subunit encoded by the FSHB gene. Resequencing and genotyping of FSHB in three European, two Asian and one African population, as well as in the great apes (chimpanzee, gorilla, orangutan), revealed low diversity and significant excess of polymorphisms with intermediate frequency alleles. Statistical tests for FSHB showed deviations from neutrality in all populations suggesting a possible effect of balancing selection. Two core haplotypes were identified (carried by 76-96.6% of each population's sample), the sequences of which are clearly separated from each other. As fertility most directly affects an organism's fitness, the carriers of these haplotypes have apparently had more success in human history to contribute to the next generation. There is a preliminary observation suggesting that the second most frequent FSHB haplotype may be associated with rapid conception success in females. Interestingly, the same haplotype is related to an ancestral FSHB variant shared with the ancestor of the great apes. The determination of the functional consequence of the two core FSHB variants may have implications for understanding and regulating human fertility, as well as in assisting infertility treatments

Discovering study-specific gene regulatory networks

This article has been made available through the Brunel Open Access Publishing Fund.Microarrays are commonly used in biology because of their ability to simultaneously measure thousands of genes under different conditions. Due to their structure, typically containing a high amount of variables but far fewer samples, scalable network analysis techniques are often employed. In particular, consensus approaches have been recently used that combine multiple microarray studies in order to find networks that are more robust. The purpose of this paper, however, is to combine multiple microarray studies to automatically identify subnetworks that are distinctive to specific experimental conditions rather than common to them all. To better understand key regulatory mechanisms and how they change under different conditions, we derive unique networks from multiple independent networks built using glasso which goes beyond standard correlations. This involves calculating cluster prediction accuracies to detect the most predictive genes for a specific set of conditions. We differentiate between accuracies calculated using cross-validation within a selected cluster of studies (the intra prediction accuracy) and those calculated on a set of independent studies belonging to different study clusters (inter prediction accuracy). Finally, we compare our method's results to related state-of-the art techniques. We explore how the proposed pipeline performs on both synthetic data and real data (wheat and Fusarium). Our results show that subnetworks can be identified reliably that are specific to subsets of studies and that these networks reflect key mechanisms that are fundamental to the experimental conditions in each of those subsets

The effectiveness of biofilm formation of daily cultures of clinically significant strains of opportunistic bacteria

Background. The formation of biofilm structures by microorganisms living in the hospital environment is a serious medical problem. To conduct correct experimental studies, it is necessary to know the speed and efficiency of biofilm formation by clinically significant species of opportunistic bacteria.   Aim: to study the kinetics of plankton culture growth and the rate of biofilm formation by clinically significant pathogens of infections associated with medical care to substantiate the methodology of further research.   Materials and methods. The strains from the working collection of the Laboratory for Microbiome and Microecology of the Scientific Сentre for Family Health and Human Reproduction Problems were used. Experiments were carried out with conditionally pathogenic microorganisms of the Enterobacteriaceae family and non-fermenting gram-negative bacteria. The optical density was measured, the total microbial number of the cell suspension was determined, and the morphological structure of the biofilm was evaluated using a light microscope on sterile cover glasses for thespecies Pseudomonas aeruginosa, Klebsiella pneumoniae and Serratia marcescens.   Results. The duration of the lag phase of the kinetic curve of cell growth varied in isolates of S. marcescens, P. aeruginosa and K. pneumoniae from 1 to 4 and 6 hours of cultivation, respectively. Despite this, the exponential growth phase was the same for all tested isolates and amounted to 4 hours. Thus, isolates of clinically significant species entered the stationary growth phase after 5–10 hours of cultivation and were characterized as fast-growing. On abiotic surfaces, after 8 hours of incubation of the tested cultures, the initial stages of the formation of biofilm structures were observed, after 20 hours the formed multilayer biofilm was visualized, after 24 hours succession occurred, new single cells were attached to the place of the detached structures.   Conclusion. The data obtained on the duration of the main stages of growth kinetics compared with the visualization of the formation of biofilm structures on abiotic surfaces should be taken into account when studying the effects of disinfectants, antiseptics and antibacterial drugs on planktonic cells and biofilm associations of clinically significant opportunistic microorganisms