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https://www.readbyqxmd.com/read/29018969/biomineralisation-of-carbonate-and-sulphate-by-the-halophilic-bacterium-halomonas-maura-at-different-manganese-concentrations
#1
Almudena Rivadeneyra, Alejandro Gonzalez-Martinez, Gabriela R Portela, Daniel J Martin-Ramos, Jesús Gonzalez-Lopez, María A Rivadeneyra
The ability of Halomonas maura to bioprecipitate carbonate and sulphate crystals in solid media at different manganese concentrations has been demonstrated in this study for the first time. The precipitated minerals were studied by X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The precipitated minerals were different based on the manganese concentration present in the medium and the incubation time. In the absence of manganese, H. maura formed pseudokutnahorite crystals; in the presence of manganese, the concentration in the culture medium determined the precipitation carbonates, such as rhodochrosite and dolomites...
October 10, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28988088/low-temperature-geothermal-systems-in-carbonate-evaporitic-rocks-mineral-equilibria-assumptions-and-geothermometrical-calculations-insights-from-the-arnedillo-thermal-waters-spain
#2
Mónica Blasco, María J Gimeno, Luis F Auqué
Geothermometrical calculations in low-medium temperature geothermal systems hosted in carbonate-evaporitic rocks are complicated because 1) some of the classical chemical geothermometers are, usually, inadequate (since they were developed for higher temperature systems with different mineral-water equilibria at depth) and 2) the chemical geothermometers calibrated for these systems (based on the Ca and Mg or SO4 and F contents) are not free of problems either. The case study of the Arnedillo thermal system, a carbonate-evaporitic system of low temperature, will be used to deal with these problems through the combination of several geothermometrical techniques (chemical and isotopic geothermometers and geochemical modelling)...
October 4, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28965179/chemical-characteristics-and-source-analysis-on-ionic-composition-of-rainwater-collected-in-the-carpathians-cold-pole-ciuc-basin-eastern-carpathians-romania
#3
Róbert Szép, Elena Mateescu, Aurelia Cristina Nechifor, Ágnes Keresztesi
A study of precipitation chemistry was conducted for 11 years (01 January 2006-31 December 2016) in the Ciuc basin, Eastern Carpathians, Romania. The studied area is an enclosed basin, also called "the Carpathians cold pole." All collected samples were analyzed for major cations and anions. HCO3(-) concentrations were calculated based on the empirical relationship between pH and HCO3(-). The multiannual arithmetic mean of pH values was found to be 6.57. The lowest and highest pH values were measured in 2009 and 2013, being 6...
October 1, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28858711/capture-and-recycling-of-ammonium-by-dolomite-aided-struvite-precipitation-and-thermolysis
#4
Liang Chen, Chun Hui Zhou, Hao Zhang, Dong Shen Tong, Wei Hua Yu, Hui Min Yang, Mao Quan Chu
The capture and reuse of NH4(+) is an ideal solution to treat NH4(+)-containing wastewater. The capture and reuse process needs to be clean and cost-effective. Currently, however, there are many obstacles, particularly in the availability, cost, and recovery of the chemical sources required. Here, we demonstrate a clean and efficient method to capture and recycle NH4(+) by a dolomite-aided struvite precipitation process. Dolomite calcined carefully in CO2 atmosphere was used as a Mg source to react with PO4(3-) (KH2PO4) and NH4(+) in model wastewater (2000 mg L(-1) NH4(+))...
August 13, 2017: Chemosphere
https://www.readbyqxmd.com/read/28812872/effect-of-mineral-dissolution-precipitation-and-co2-exsolution-on-co2-transport-in-geological-carbon-storage
#5
Ruina Xu, Rong Li, Jin Ma, Di He, Peixue Jiang
Geological carbon sequestration (GCS) in deep saline aquifers is an effective means for storing carbon dioxide to address global climate change. As the time after injection increases, the safety of storage increases as the CO2 transforms from a separate phase to CO2(aq) and HCO3(-) by dissolution and then to carbonates by mineral dissolution. However, subsequent depressurization could lead to dissolved CO2(aq) escaping from the formation water and creating a new separate phase which may reduce the GCS system safety...
August 16, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28795400/application-of-micro-ftir-mapping-and-sem-to-study-compositional-heterogeneity-of-siltstones-example-from-the-late-devonian-early-mississippian-middle-bakken-member
#6
C Gasaway, M Mastalerz, F Krause, C Clarkson, C Debuhr
This paper explores the applicability of micro-FTIR mapping to study heterogeneity of organic matter-lean siltstones. Closely spaced samples of Late Devonian dolomitic siltstones of the Middle Bakken Member were analysed with micro-FTIR, powder X-ray diffraction, and scanning electron microscopy (SEM) to explore the distribution and chemical properties of organic matter (OM), muscovite/feldspar/clay group, carbonates, and quartz, and their influence on porosity and permeability of these rocks. Our results show that quartz is the dominant component of the samples, and the main mineralogical differences between the samples are reflected in the abundance of carbonate minerals...
August 10, 2017: Journal of Microscopy
https://www.readbyqxmd.com/read/28763288/particle-size-distribution-a-key-factor-in-estimating-powder-dustiness
#7
Ana López-Lilao, Forner Vicenta Sanfélix, Gasch Gustavo Mallol, Gimeno Eliseo Monfort
ASTRACT A wide variety of raw materials, involving more than twenty samples of quartzes, feldspars, nephelines, carbonates, dolomites, sands, zircons, and alumina, were selected and characterised. Dustiness, i.e. a materials' tendency to generate dust on handling, was determined using the continuous drop method. These raw materials were selected to encompass a wide range of particle sizes (1.6-294 µm) and true densities (2650-4680 kg/m(3)). The dustiness of the raw materials, i.e. their tendency to generate dust on handling, was determined using the continuous drop method...
August 1, 2017: Journal of Occupational and Environmental Hygiene
https://www.readbyqxmd.com/read/28757219/olivine-dolomite-and-ceramic-filters-in-one-vessel-to-produce-clean-gas-from-biomass
#8
Sergio Rapagnà, Katia Gallucci, Pier Ugo Foscolo
Heavy organic compounds produced during almond shells gasification in a steam and/or air atmosphere, usually called tar, are drastically reduced in the product gas by using simultaneously in one vessel a ceramic filter placed in the freeboard and a mixture of olivine and dolomite particles in the fluidized bed of the gasifier. The content of tar in the product gas during a reference gasification test with air, in presence of fresh olivine particles only, was 8600mg/Nm(3) of dry gas. By gasifying biomass with steam at the same temperature level of 820°C in a bed of olivine and dolomite (20% by weight), and in the presence of a catalytic ceramic filter inserted in the freeboard of the fluidized bed gasifier, the level of tar was brought down to 57mg/Nm(3) of dry producct gas, with a decrease of more than two orders of magnitude...
July 27, 2017: Waste Management
https://www.readbyqxmd.com/read/28738558/elemental-source-attribution-signatures-for-calcium-ammonium-nitrate-can-fertilizers-used-in-homemade-explosives
#9
Carlos G Fraga, Alexander V Mitroshkov, Nikhil S Mirjankar, Brian P Dockendorff, Angie M Melville
Calcium ammonium nitrate (CAN) is a widely available fertilizer composed of ammonium nitrate (AN) mixed with some form of calcium carbonate such as limestone or dolomite. CAN is also frequently used to make homemade explosives. The potential of using elemental profiling and chemometrics to match both pristine and reprocessed CAN fertilizers to their factories of origin for use in future forensic investigations was examined. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine the concentrations of 64 elements in 125 samples from 11 CAN stocks from 6 different CAN factories...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28737010/carbonate-ooids-of-the-mesoarchaean-pongola-supergroup-south-africa
#10
M Siahi, A Hofmann, S Master, C W Mueller, A Gerdes
Ooids from the Mesoarchaean Chobeni Formation, Pongola Supergroup, KwaZulu-Natal, South Africa are older than any ooids reported to date. They are made of dolomite and ankerite and show concentric, radial-concentric, micritic, and radial fabrics. Radial ooids are interpreted to have originated from high-Mg-calcite and probably formed by microbial activity in a low-energy regime, while concentric ooids had an aragonite precursor and formed biotically under agitated/high-energy environmental conditions. Micritic ooids formed via the recrystallization of concentric ooids...
July 24, 2017: Geobiology
https://www.readbyqxmd.com/read/28735325/characterization-of-endolithic-culturable-microbial-communities-in-carbonate-rocks-from-a-typical-karst-canyon-in-guizhou-china
#11
Yuan Tang, Jian-Zhong Cheng, Bin Lian
The endolithic environment is a ubiquitous habitat for microorganisms and a critical interface between biology and geology. In this study, a culture-based method and the phylogenetic analysis based on 16S rRNA and internal transcribed spacer (ITS) sequences were used to investigate the diversity of endolithic bacteria and fungi in two main types of carbonate rocks (namely dolomite and limestone) from Nanjiang Canyon in Guizhou karst area, China. The results of bacterial diversity indicated that all bacteria isolated from dolomite and limestone rocks were divided into 4 bacterial groups, including Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes...
January 2, 2017: Polish Journal of Microbiology
https://www.readbyqxmd.com/read/28735089/biodeterioration-of-marble-in-an-underwater-environment
#12
Beatriz Cámara, Mónica Álvarez de Buergo, Manuel Bethencourt, Tomás Fernández-Montblanc, Mauro F La Russa, Michela Ricca, Rafael Fort
This study examines the deterioration of geomaterials used throughout history that today may be found lying on the ocean floor. Submerged archaeological sites including cargoes from shipwrecks or ancient city ruins have been a topic of interest from a perspective of in situ musealization, as a way of making underwater cultural heritage accessible to the public. In an experimental study conducted at an underwater archaeological site in the Bay of Cádiz (SW Spain), we subjected two types of marble (Carrara and Macael) to three conditions to which submerged archaeological objects are often exposed: full exposure to the water column, natural processes of burial and unearthing, or permanent burial...
December 31, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28711248/the-effect-of-source-of-supplemental-dietary-calcium-and-magnesium-in-the-peripartum-period-and-level-of-dietary-magnesium-postpartum-on-mineral-status-performance-and-energy-metabolites-in-multiparous-holstein-cows
#13
B M Leno, S E LaCount, C M Ryan, D Briggs, M Crombie, T R Overton
The objective of this study was to determine the effects of feeding different supplemental sources of Ca and Mg in the peripartum period, and different dietary levels of Mg postpartum, on plasma mineral status, performance, and aspects of energy metabolism in transition dairy cows. Multiparous Holstein cows (n = 41) were used in a completely randomized design with a 2 × 2 factorial arrangement of treatments starting at 28 d before expected parturition. Main effects were source assignments (CS = common sources of supplemental Ca and Mg, or MA = a blend of common and commercial mineral sources with supplemental minerals primarily from a commercial Ca-Mg dolomite source; MIN-AD, Papillon Agricultural Company Inc...
September 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28691279/paleoecology-of-neoproterozoic-hypersaline-environments-biomarker-evidence-for-haloarchaea-methanogens-and-cyanobacteria
#14
R Schinteie, J J Brocks
While numerous studies have examined modern hypersaline ecosystems, their equivalents in the geologic past, particularly in the Precambrian, are poorly understood. In this study, biomarkers from ~820 million year (Ma)-old evaporites from the Gillen Formation of the mid-Neoproterozoic Bitter Springs Group, central Australia, are investigated to elucidate the antiquity and paleoecology of halophiles. The sediments were composed of alternating laminae of dolomitized microbial mats and up to 90% anhydrite. Solvent extraction of these samples yielded thermally well-preserved hydrocarbon biomarkers...
September 2017: Geobiology
https://www.readbyqxmd.com/read/28679041/synthesis-photocatalytic-and-antifungal-properties-of-mgo-zno-and-zn-mg-oxide-nanoparticles-for-the-protection-of-calcareous-stone-heritage
#15
A Sierra-Fernandez, S C De la Rosa-García, L S Gomez-Villalba, S Gómez-Cornelio, M E Rabanal, R Fort, P Quintana
More recently, the biological colonization of stone heritage and consequently its biodeterioration has become the focus of numerous studies. Among all microorganisms, fungi are considered to be one of the most important colonizers and biodegraders on stone materials. This is why the development of new antifungal materials requires immediate action. ZnMgO nanoparticles (NPs) have several exciting applications in different areas, highlighting as an efficient antimicrobial agent for medical application. In this research, the application of Zn-doped MgO (Mg1-xZnxO, x = 0...
July 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28666196/dynamics-of-soil-organic-carbon-in-density-fractions-during-post-agricultural-succession-over-two-lithology-types-southwest-china
#16
Li Wen, Dejun Li, Hao Chen, Kelin Wang
Agricultural abandonment has been proposed as an effective way to enhance soil organic carbon (SOC) sequestration. Nevertheless, SOC sequestration in the long term is largely determined by whether the stable SOC fractions will increase. Here the dynamics of SOC fractions during post-agricultural succession were investigated in a karst region, southwest China using a space-for-time substitution approach. Cropland, grassland, shrubland and secondary forest were selected from areas underlain by dolomite and limestone, respectively...
June 27, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28664494/can-liming-change-root-anatomy-biomass-allocation-and-trace-element-distribution-among-plant-parts-of-salix-%C3%A3-smithiana-in-trace-element-polluted-soils
#17
Stanislava Vondráčková, Pavel Tlustoš, Jiřina Száková
Willows (Salix spp.) are considered to be effective for the phytoremediation of trace elements from contaminated soils, but their efficiency is limited in heavily polluted soils because of poor growth. Liming can be a desirable measure to decrease the plant availability of elements, resulting in improved plant development. Notably, large root area and maximum soil penetration are basic parameters that improve the efficiency of phytoremediation. The impact of soil chemical properties on willow root anatomy and the distribution of trace elements below-ground have rarely been studied...
June 29, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28621394/influence-of-various-soluble-carbonates-on-the-hydration-of-portland-cement-studied-by-x-ray-diffraction
#18
Simona Medvešček, Venčeslav Kaučič, Anton Meden
The effect of limestone on the hydration of Portland cement has been studied by many researchers. However, a possible influence of adding more soluble carbonates was not explained. Therefore we executed a qualitative and quantitative research on the influence of slightly soluble (CaCO3, MgCO3, dolomite), medium soluble (Li2CO3) and highly soluble (K2CO3 and KHCO3) carbonates on the hydration. Blending of Portland cement with differently soluble carbonates was found to influence the hydrate assemblage of the hydrated cement...
June 2017: Acta Chimica Slovenica
https://www.readbyqxmd.com/read/28580442/cation-exchange-in-the-presence-of-oil-in-porous-media
#19
R Farajzadeh, H Guo, J van Winden, J Bruining
Cation exchange is an interfacial process during which cations on a clay surface are replaced by other cations. This study investigates the effect of oil type and composition on cation exchange on rock surfaces, relevant for a variety of oil-recovery processes. We perform experiments in which brine with a different composition than that of the in situ brine is injected into cores with and without remaining oil saturation. The cation-exchange capacity (CEC) of the rocks was calculated using PHREEQC software (coupled to a multipurpose transport simulator) with the ionic composition of the effluent histories as input parameters...
April 20, 2017: ACS earth & space chemistry
https://www.readbyqxmd.com/read/28559731/developing-a-molecular-identification-assay-of-old-landraces-for-the-genetic-authentication-of-typical-agro-food-products-the-case-study-of-the-barley-agordino
#20
Fabio Palumbo, Giulio Galla, Gianni Barcaccia
The orzo Agordino is a very old local variety of domesticated barley (Hordeum vulgare ssp. distichum L.) that is native to the Agordo District, Province of Belluno, and is widespread in the Veneto Region, Italy. Seeds of this landrace are widely used for the preparation of very famous dishes of the dolomitic culinary tradition such as barley soup, bakery products and local beer. Understanding the genetic diversity and identity of the Agordino barley landrace is a key step to establish conservation and valorisation strategies of this local variety and also to provide molecular traceability tools useful to ascertain the authenticity of its derivatives...
March 2017: Food Technology and Biotechnology
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