Factors affecting hematite precipitation and characterization of the product from simulated sulphate-chloride solutions at 150 °C

2018 ◽  
Vol 179 ◽  
pp. 8-19 ◽  
Author(s):  
Tasawar Javed ◽  
Mingliang Xie ◽  
Edouard Asselin
2012 ◽  
Vol 10 (6) ◽  
pp. 1709-1759 ◽  
Author(s):  
Milan Melnik ◽  
Ondrej Sprusansky ◽  
Clive Holloway

AbstractThis review covers almost two hundred and twenty heterobinuclear platinum compounds in which Pt⋯M separation is over 3.0 Å. The M is a transition metal (Cu, Ag, Au, Ti, V, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni and Pd). There is an example of a lanthanide, Yb and a actinide, U. The Pt atom has oxidation numbers 0, +2 and +4. The Pt coordination geometries include trigonal planar Pt(0); square planar Pt(II); trigonal bipyramidal, and pseudo octahedral Pt(IV), with the most frequent being square planar. The most common ligands for Pt are P and C donor atoms, as well as a chlorine atom. The Pt — Ag distance of 3.002(1) Å is the shortest found in this series. There are examples which contain two crystallographically independent molecules, which differ mostly by degree of distortion and even one unique example, which contains eight such molecules. These are examples of distortion isomerism. Factors affecting bond lengths and angles are discussed and some ambiguities in coordination polyhedral are outlined.


2005 ◽  
Vol 2005 ◽  
pp. 136-136
Author(s):  
S. Z. Mirhosseini ◽  
M. Mavajpoor ◽  
M. Ghanipoor ◽  
A. Seidavi

Silkworms are well-known industrial insects, which produce natural fiber silk. Because of economic importance for silk yarn, an effort to breed new silkworm variety has been made for thousand years. High cocoon yielding due to high resistance, high silk reeling ability and productivity, better silk quality in neatness and lousiness is essential for new silkworm variety to increase silk productivity. Today, several hundred varieties have been bred accordingly various interests and purposes (Kang et al., 2001, 2002). Pupation rate, single cocoon weight, cocoon shell weight and cocoon shell percentage are the main factors affecting the high yielding of cocoon (Kang et al., 2001, 2002). Native silkworm varieties have the low performance and could not be commercially employed. Indigenous strains are valuable genetic resources. They have been affected by natural selection in the successive generations and adapted to indigenous diseases and environmental conditions. Genetic and phenotypic characterization of locally available native silkworm populations provides essential information to make rational decisions for the improvement and development of effective breeding programmes. Hence, the present study was undertaken to identify genetic potential of indigenous silkworm for designing suitable breeding programmes.


Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 669
Author(s):  
Tasawar Javed ◽  
Edouard Asselin

The purification of hydrometallurgical process solutions by Fe(III) precipitation is a common and large-scale industrial operation. This step is notorious for valuable metal loss occurring with the iron precipitation product, which is usually directed to tailings. In this study, factors affecting Fe(III) precipitation and associated copper loss were studied in synthetic process solutions using statistical methods. The variables studied were: Initial acid concentration, retention time, seed addition, and initial Fe(III), Cu(II), and chloride concentrations. The importance of each variable and its interaction effects were studied against two responses, i.e., percent of Fe(III) precipitated as hematite and percent of Cu lost to solids. The results showed that a combination of high acid and moderate seeding was required to simultaneously achieve high proportions of Fe(III) precipitated as hematite and lower copper loss to the precipitates. High acid concentrations create low supersaturation for Fe(III), which minimizes the consequences of homogeneous nucleation and favors particle growth.


Microbiology ◽  
2010 ◽  
Vol 156 (7) ◽  
pp. 2035-2045 ◽  
Author(s):  
Claudia Picozzi ◽  
Gaia Bonacina ◽  
Ileana Vigentini ◽  
Roberto Foschino

Lactobacillus sanfranciscensis is a lactic acid bacterium that characterizes the sourdough environment. The genetic differences of 24 strains isolated in different years from sourdoughs, mostly collected in Italy, were examined and compared by PFGE and multilocus sequence typing (MLST). The MLST scheme, based on the analysis of six housekeeping genes (gdh, gyrA, mapA, nox, pgmA and pta) was developed for this study. PFGE with the restriction enzyme ApaI proved to have higher discriminatory power, since it revealed 22 different pulsotypes, while 19 sequence types were recognized through MLST analysis. Notably, restriction profiles generated from three isolates collected from the same firm but in three consecutive years clustered in a single pulsotype and showed the same sequence type, emphasizing the fact that the main factors affecting the dominance of a strain are correlated with processing conditions and the manufacturing environment rather than the geographical area. All results indicated a limited recombination among genes and the presence of a clonal population in L. sanfranciscensis. The MLST scheme proposed in this work can be considered a useful tool for characterization of isolates and for in-depth examination of the strain diversity and evolution of this species.


1997 ◽  
Vol 3 (1) ◽  
pp. 6-9 ◽  
Author(s):  
Toshiyuki WATANABE ◽  
Yutaka HASHIMOTO ◽  
Toshio JOH ◽  
Toshiro HAYAKAWA
Keyword(s):  

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