scholarly journals Mineralogical and Chemical Characteristics of Gossan Waste Rocks from a Gold Mine in Northeastern Thailand

2017 ◽  
pp. 1-13
Author(s):  
Thitiphan Assawincharoenkij ◽  
Christoph Hauzenberger ◽  
Chakkaphan Sutthirat
Keyword(s):  
Low Cost ◽  
Feasibility Studies ◽  
Chemical Compositions ◽  
Type I ◽  
Gold Mine ◽  
Electron Probe Micro Analyzer ◽  
Color Type ◽  
Yellow Color ◽  
Red Color ◽  
Northeastern Thailand

The mineralogical and chemical compositions of various ocher gossans from a gold mine in northeastern Thailand were investigated, including some heavy metals and other toxic elements. Mineralogical characteristics were carried out using X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM) whereas chemical compositions were analyzed using Electron Probe Micro-Analyzer (EPMA). These ocher gossans can be classified, initially based on Munsell color, into five types: type-I (pale-yellow color), type-II (brownish-yellow color), type-III (yellowish-brown color), type-IV (dusky-red color) and type-V (red color). The primary silicate minerals (i.e., quartz, garnet epidote and amphibole) are found in type -I, -II, -III and -IV. They appear to be composed of skarn rock. On the other hand, the secondary minerals (i.e., goethite, jarosite, ankerite, montmorillonite, magnetite, gypsum and secondary quartz) are observed in types-II, -III, -IV and -V. As and Cu are found crucially in types-III, -IV and -V in which both elements can be adsorbed by goethite and/or jarosite. As the result, the gossan rocks in this area are natural adsorbents with high potential to reduce As and Cu contamination into the ecosystem. Therefore, the gossan, a natural attenuation material, is recommended for site remediation because of its low cost and local abundance. Feasibility studies should be conducted to further investigate the potential.

scholarly journals A20 DIAGNOSTIC ACCURACY OF A LOW COST, WIDELY AVAILABLE TEST STRIP FOR PREDICTING A POSITIVE FECAL CALPROTECTIN TEST

2021 ◽  
Vol 4 (Supplement_1) ◽  
pp. 210-212
Author(s):  
R Trasolini ◽  
S Wong ◽  
B Salh
Keyword(s):  
Sample Size ◽  
Likelihood Ratio ◽  
Gold Standard ◽  
Low Cost ◽  
Positive Likelihood Ratio ◽  
Negative Likelihood Ratio ◽  
Rapid Test ◽  
Test Strip ◽  
Fecal Calprotectin ◽  
Type I

Abstract Background Fecal calprotectin is a non-invasive test of colonic inflammation used for monitoring inflammatory bowel disease activity and for risk stratifying non-specific colonic symptoms. Calprotectin is a leukocyte specific enzyme. A similar test, leukocyte esterase is used to detect leukocytes in urine and is widely available as a low-cost point-of-care test strip. We hypothesize that an unmodified version of the urine test strip would be highly accurate in predicting a positive fecal calprotectin test in a real world sample of patients. Aims To explore a low cost, rapid alternative to the fecal calprotectin test Methods All inpatient and outpatient stool samples tested for calprotectin by the Vancouver General Hospital laboratory from February 2020 to November 2020 were included prospectively. Samples were simultaneously tested for fecal leukocyte esterase using an unmodified Roche Cobas Chemstrip urinalysis test strip by central lab personnel. An identical aliquot was sent to LifeLabs for calprotectin as per standard protocol. All samples were suspended in buffer using established laboratory protocols prior to testing. Fecal leukocyte esterase results were reported as 0–4+ based on visual interpretation, calprotectin results were reported as mcg/g of stool. REB review and approval was obtained prior to data collection. Sensitivity, Specificity and AUROC were calculated using Microsoft Excel and JROCFIT. Results 26 samples were collected. Using a fecal calprotectin greater than 120 mcg/g as a gold standard an AUROC of 0.89 (SE= .06) was calculated. A leukocyte esterase reading of 2+ or greater had the best test characteristics based on ROC curve analysis. Using this cutoff, 21/26 samples were concordant, giving an accuracy of 80.8%, sensitivity of 90.9% and specificity of 73.3%. Positive likelihood ratio was 8.07 and negative likelihood ratio was 0.29. Assuming an AUROC of 0.8, the sample size N=26 is 90% powered (β=0.9) to predict the true AUROC within 0.1 with a type I error rate of .05 (α<.05). Conclusions This study suggests application of a prepared stool sample to a urinalysis test strip gives a result highly predictive of a positive fecal calprotectin test. Further results are being collected prospectively to improve the robustness of these preliminary data. Secondary outcomes including comparison to endoscopy and biopsy results where available are planned if an adequate sample size can be accrued. Future studies justifying independent clinical use of leukocyte esterase would require a common gold standard comparator such as endoscopy. Fecal calprotectin testing is not universally insured and is not available as a rapid test strip. Use of fecal leukocyte esterase may reduce costs and shorten time to results if proven to be independently reliable. Funding Agencies None

scholarly journals The Mineral Chemistry of Chlorites and Its Relationship with Uranium Mineralization from Huangsha Uranium Mining Area in the Middle Nanling Range, SE China

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 199 ◽  
Author(s):  
Dehai Wu ◽  
Jiayong Pan ◽  
Fei Xia ◽  
Guangwen Huang ◽  
Jing Lai
Keyword(s):  
Mining Area ◽  
Uranium Mining ◽  
Uranium Mineralization ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Type I ◽  
Low Oxygen ◽  
Nanling Range ◽  
The Relationship ◽  
Uranium Mining Area

The Huangsha uranium mining area is located in the Qingzhangshan uranium-bearing complex granite of the Middle Nanling Range, Southeast China. This uranium mining area contains three uranium deposits (Liangsanzhai, Egongtang, and Shangjiao) and multiple uranium occurrences, showing favorable mineralization conditions and prospecting potential for uranium mineral resources. Chloritization is one of the most important alteration types and prospecting indicators in this mining area. This study aims to unravel the formation environment of chlorites and the relationship between chloritization and uranium mineralization, based on detailed field work and petrographic studies of the wallrock and ore samples from the Huangsha uranium mining area. An electron probe microanalyzer (EPMA) was used in this study to analyze the paragenetic association, morphology, and chemical compositions of chlorite, to classify chemical types and to calculate formation temperatures and n(Al)/n(Al + Mg + Fe) values of chlorite. The formation mechanism and the relationship with uranium mineralization of the uranium mining area are presented. Some conclusions from this study are: (1) There are five types of chlorites, including the chlorite formed by the alteration of biotite (type-I), by the metasomatism of feldspar with Fe–Mg hydrothermal fluids (type-II), chlorite vein/veinlet filling in fissures (type-III), chlorite closely associated with uranium minerals (type-IV), and chlorite transformed from clay minerals by adsorbing Mg- and Fe-components (type-V). (2) The chlorite in the Huangsha uranium mining area belongs to iron-rich chlorite and is mainly composed of chamosite, partly clinochlore, which are the products of multiple stages of hydrothermal action. The original rocks are derived from argillite, and their formation temperatures vary from 195.7 °C to 283.0 °C, with an average of 233.2 °C, suggesting they formed under a medium to low temperature conditions. (3) The chlorites were formed under reducing conditions with low oxygen fugacity and relatively high sulfur fugacity through two formation mechanisms: dissolution–precipitation and dissolution–migration–precipitation; (4) The chloritization provided the required environment for uranium mineralization, and promoted the activation, migration, and deposition of uranium.

Mineralogy and geochemistry of tailings from a gold mine in northeastern Thailand

2017 ◽  
Vol 23 (2) ◽  
pp. 364-387 ◽  
Author(s):  
Thitiphan Assawincharoenkij ◽  
Christoph Hauzenberger ◽  
Chakkaphan Sutthirat
Keyword(s):  
Gold Mine ◽  
Northeastern Thailand

Preparation and Application of Biochars for Organic and Microbial Control in Wastewater Treatment Regimes

2019 ◽  
pp. 19-34 ◽  
Author(s):  
Victor Odhiambo Shikuku ◽  
Wilfrida N. Nyairo ◽  
Chrispin O. Kowenje
Keyword(s):  
Organic Pollutants ◽  
Organic Contaminants ◽  
Activated Carbons ◽  
Low Cost ◽  
Microbial Control ◽  
Chemical Compositions ◽  
Preparation Methods ◽  
Factors Affecting ◽  
Surface Areas ◽  
Control Factors

Biochars have been extensively applied in soil remediation, carbon sequestration, and in climate change mitigation. However, in recent years, there has been a significant increase in biochar research in water treatment due to their stupendous adsorptive properties for various contaminants. This is attributed to their large surface areas, pore structures, chemical compositions, and low capital costs involved making them suitable candidates for replacing activated carbons. This chapter discusses the preparation methods and properties of biochars and their removal efficacy for organic contaminants and microbial control. Factors affecting adsorption and the mechanisms of adsorption of organic pollutants on biochars are also concisely discussed. Biochars present environmentally benign and low-cost adsorbents for removal of both organic pollutants and microbial control for wastewater purification systems.

Establishing the Diagnosis

2009 ◽  
Author(s):  
Daniel A. Brinton ◽  
Charles P. Wilkinson
Keyword(s):  
Retinal Detachment ◽  
Posterior Pole ◽  
Peripheral Retina ◽  
Retinal Breaks ◽  
Yellow Color ◽  
Red Color ◽  
The Central Nervous System ◽  
Retinal Artery ◽  
Ciliary Artery ◽  
Choroidal Vessels

The differential diagnosis of rhegmatogenous retinal detachment includes secondary (nonrhegmatogenous) retinal detachment and other entities that may simulate a retinal detachment. Nonrhegmatogenous detachments are categorized as exudative (serous) and tractional detachments. Conditions that may be mistaken for retinal detachment include retinoschisis, choroidal detachment or tumors, and vitreous membranes. Sometimes benign findings in the peripheral retina are mistaken for retinal breaks. The most prominent feature of the fundus is the optic nerve head or disc, the only place in the human body that affords a direct view of a tract of the central nervous system. The foveola, the functional center of the fundus, is located in the center of the fovea, which has a diameter of about 5°. The macula is centered on the fovea and has a diameter of about 17°. The multiple branches of the central retinal artery are readily identifi ed by their bright red color and relatively narrow caliber. The multiple tributaries of the central retinal vein are recognized by their dark red color and relatively wider caliber. In a darkly pigmented fundus, the choroidal vessels in the posterior pole can be obscured from view, but in an eye with minimal pigment, they are readily visible. The venous tributaries of the choroid that make up the vortex veins are usually easily seen. The most prominent features of the choroidal venous system are the vortex ampullae, of which there are usually four (but sometimes more). They are located approximately in the 1-, 5-, 7-, and 11-o’clock meridians, just posterior to the equator. The horizontal meridians are usually identifiable by their radially oriented, long posterior ciliary nerves, and infrequently the long posterior ciliary artery can be seen adjacent to the nerve. The nerve is relatively broad and has a yellow color, and the artery is identifiable by its red color. The artery is usually inferior to the nerve temporally, and superior to it nasally (Figure 5–1).

Observation of the Hong-Ou-Mandel Dip by Using Type-I Spontaneous Parametric Down Conversion Light with a Low-Cost Coincidence Circuit

2017 ◽  
Vol 67 (12) ◽  
pp. 1528-1533
Author(s):  
Sung-Wook HAN ◽  
Munkhbaatar PUREVDOR ◽  
Hyung-Nam NOH ◽  
Heonoh KIM ◽  
Myung-Whun KIM*
Keyword(s):  
Low Cost ◽  
Type I ◽  
Coincidence Circuit ◽  
Parametric Down Conversion ◽  
Down Conversion

RAPID, SENSITIVE N0N-RADI0ACTIVE QUANTIFICATION AND ANALYSIS OF PLASMA VON WILLEBRAND FACTOR (vWF) MULTIMERS

1987 ◽  
Author(s):  
J L Moake ◽  
M A Harris ◽  
C E Whitley ◽  
C P Alfrey
Keyword(s):  
Alkaline Phosphatase ◽  
Milk Proteins ◽  
Classical Type ◽  
Type I ◽  
Leukocyte Alkaline Phosphatase ◽  
Red Color ◽  
Alternative Techniques ◽  
Relative Deficiency ◽  
Von Willebrand ◽  
Willebrand Factor

Assessment of plasma vWF abnormalities by clinical coagulation laboratories is difficult because the available test systems for vWF antigen quantification and multimer analysis are expensive, laborious, and require days, radioactive anti-vWF antibodies and autoradiographic methods. We have devised simple, rapid, sensitive alternative techniques for vWF quantification and multimer analysis that can be readily installed in clinical laboratories. Plasma vWF antigen quantification is by a 2 hour enzyme immunoassay that accurately detects levels as low as 0.23% of normal. Plasma vWF to be quantified is bound to polyclonal monospecific antihuman vWF attached to small glass beads, and anti-human vWF conjugated with alkaline phosphatase is added to make an insoluble "sandwich." A substrate solution consisting of phenylphosphate and 4-amino-antipurine is added, followed by potassium ferricyanide. Optical density (at 490-510 nm) of the red color that develops is directly proportional to the plasma concentration of vWF antigen. Plasma vWF multimeric analysis is by a one-day electrophoretic immunobiot procedure. Plasma vWF multimer forms are solubilized in SDS-urea-Tris-EDTA, separated by horizontal 1% agarose gel electrophoresis, and transferred to a cationic membrane. Other protein binding sites on the membrane are blocked with milk proteins, and the membrane is overlaid with anti-vWF IgG linked to alkaline phosphatase. vWF multimers are then displayed as blue bands by soaking the membrane in an alkaline solution of the histochemical stain, fast blue RR (commonly used for leukocyte alkaline phosphatase scoring) dissolved in naphtol AS-MX phosphate. These simple, non-radioactive procedures performed together permit the rapid distinction of classical (Type I) von Willebrand's disease (vWD), characterized by low vWF antigen and normal multimers, from the Type II vWD syndromes, characterized by a relative deficiency of the largest plasma vWF forms. Unusually large vWF multimers, present in remission plasma of patients with chronic relapsing thrombotic thrombocytopenic purpura (TTP), are also easily detected using this rapid system of multimer analysis.

Determination and detoxification of cyanide in gold mine tailings: A review

2019 ◽  
Vol 37 (11) ◽  
pp. 1117-1126 ◽  
Author(s):  
Cosmos Anning ◽  
Junxiang Wang ◽  
Ping Chen ◽  
Idermunkh Batmunkh ◽  
Xianjun Lyu
Keyword(s):  
Mine Tailings ◽  
Weak Acid ◽  
Acid Dissociation ◽  
Chemical Compositions ◽  
Gold Mine ◽  
Chemical Methods ◽  
Gold Mine Tailings ◽  
Minerals Processing ◽  
The Impact ◽  
Gold Tailings

Cyanide is among the most toxic chemicals widely employed in the cyanidation process to leach precious minerals, such as gold and silver, by the minerals processing companies worldwide. This present article reviews the determination and detoxification of cyanide found in gold mine tailings. Most of the cyanide remains in the solution or the slurries after the cyanidation process. The cyanide species in the gold tailings are classified as free cyanide, weak acid dissociation, and metallocyanide complexes. Several methods, such as colorimetric, titrimetric, and electrochemical, have been developed to determine cyanide concentrations in gold mine effluents. Application of physical, natural, biological, and chemical methods to detoxify cyanide to a permissible limit (50 mg L−1) can be achieved when the chemical compositions of cyanide (type of species) present in the tailings are known. The levels of cyanide concentration determine the impact it will have on the environment.

scholarly journals Feasibility Study for a Chemical Process Particle Size Characterization System for Explosive Environments Using Low Laser Power

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 911
Author(s):  
Jesse Ross-Jones ◽  
Tobias Teumer ◽  
Susann Wunsch ◽  
Lukas Petri ◽  
Hermann Nirschl ◽  
...  
Keyword(s):  
Light Scattering ◽  
Low Cost ◽  
Particle Diameter ◽  
Feasibility Studies ◽  
Fast Response ◽  
The Novel ◽  
Micro Channels ◽  
Size Characterization ◽  
Novel Method ◽  
Particle Size Characterization

The industrial particle sensor market lacks simple, easy to use, low cost yet robust, safe and fast response solutions. Towards development of such a sensor, for in-line use in micro channels under continuous flow conditions, this work introduces static light scattering (SLS) determination of particle diameter using a laser with an emission power of less than 5 µW together with sensitive detectors with detection times of 1 ms. The measurements for the feasibility studies are made in an angular range between 20° and 160° in 2° increments. We focus on the range between 300 and 1000 nm, for applications in the production of paints, colors, pigments and crystallites. Due to the fast response time, reaction characteristics in microchannel designs for precipitation and crystallization processes can be studied. A novel method for particle diameter characterization is developed using the positions of maxima and minima and slope distribution. The novel algorithm to classify particle diameter is especially developed to be independent of dispersed phase concentration or concentration fluctuations like product flares or signal instability. Measurement signals are post processed and particle diameters are validated against Mie light scattering simulations. The design of a low cost instrument for industrial use is proposed.

Sign in / Sign up

Export Citation Format

Share Document