نتایج جستجو برای: limestone mines

تعداد نتایج: 12941  

Journal: :Saudi journal of biological sciences 2012
D Cunha Zied A Pardo-Giménez M T de Almeida Minhoni R L Villas Boas M Alvarez-Orti J E Pardo-González

The aim of this study was to analyze yields, biological efficiency, earliness (expressed as days to first harvest), and precociousness and establish models for the mushroom growing according to these parameters. The experiment followed a double factorial design with four sources of calcium (calcitic limestone, calcitic limestone + gypsum, dolomitic limestone and dolomitic limestone + gypsum) an...

Journal: :Journal of the Air & Waste Management Association 2000
D A Kirchgessner S D Piccot S S Masemore

Past efforts to estimate methane emissions from underground mines, surface mines, and other coal mine operations have been hampered, to different degrees, by a lack of direct emissions data. Direct measurements have been completely unavailable for several important coal mining operations. A primary goal of this study was to collect new methane emissions measurements and other data for the most ...

Journal: :Journal of animal science 1990
M L Christiansen K E Webb

Five Angus heifers (285 kg) with duodenal and ileal cannulas were used to study the effects of feeding mineral acid neutralizers on digesta and fecal pH, intestinal acid flow, DM, starch and CP digestion and amino acid absorption in cattle fed a high-concentrate diet (7.5 kg/d). The experimental design was a 5 x 5 latin square. Treatments included control diet alone or control diet with the add...

Journal: :Science 1966
V E Barnes A J Boucot P E Cloud R H Miller A R Palmer

Silurian outcrops, not previously recorded from central Texas, have been identified from the Llano uplift, where they occur in collapse structures within the Lower Ordovician Honeycut Formation of the Ellenburger Group. The formation is a pinkish-gray granular limestone, contains fossils of probable Wenlock age, and is named the Starcke Limestone.

Journal: :British journal of industrial medicine 1956
S BRIDGE DAVIS G NAGELSCHMIDT

It is generally believed that exposure to limestone dust does not present a pneumoconiosis hazard. However, Doig (1955) has recently described cases of silicosis amongst limestone workers after prolonged exposure to high dust concentrations. The limestones concerned contained from 5 to 15% quartz as impurity, and dissolution of the calcium carbonate in the lung would leave a quartz-rich residue...

Journal: :Journal of hazardous materials 2012
Adarlêne M Silva Rosa M F Lima Versiane A Leão

Limestone can be an option for sulfate sorption, particularly from neutral mine drainages because calcium ions on the solid surface can bind sulfate ions. This work investigated sulfate removal from mine waters through sorption on limestone. Continuous stirred-tank experiments reduced the sulfate concentration from 588.0mg/L to 87.0mg/L at a 210-min residence time. Batch equilibrium tests showe...

Journal: :Physical chemistry chemical physics : PCCP 2016
Antonio de la Calle Martos Jose Manuel Valverde Pedro E Sanchez-Jimenez Antonio Perejón Cristina García-Garrido Luis A Perez-Maqueda

One of the major drawbacks that hinder the industrial competitiveness of the calcium looping (CaL) process for CO2 capture is the high temperature (∼930-950 °C) needed in practice to attain full calcination of limestone in a high CO2 partial pressure environment for short residence times as required. In this work, the multicycle CO2 capture performance of dolomite and limestone is analysed unde...

2014
W. Li R. Angel S.-W. Kim E. Jiménez-Moreno M. Proszkowiec-Weglarz B. F. Iglesias S. J. Wilkinson A. J. Cowieson

A study was done to determine whether broilers can regulate Ca intake when limestone is provided separately or mixed with a crumbled feed of variable Ca and P content, and the influence of this on performance and apparent ileal digestibility (AID) of Ca and P (AIDP). Twelve crumbled diets were fed from 10 to 20 d of age (8 replicates, 8 broilers/replicate). Diets A to D contained 0.28% nonphyta...

2011
MARK A. HAYES

In western United States, both mine reclamations and renewed mining at previously abandoned mines have increased substantially in the last decade. This increased activity may adversely impact bats that use these mines for roosting. Townsend’s big-eared bat (Corynorhinus townsendii) is a species of conservation concern that may be impacted by ongoing mine reclamation and renewedmineral extractio...

Journal: :Applied sciences 2021

A smart helmet-based wearable personnel proximity warning system was developed to prevent collisions between equipment and pedestrians in mines. The helmet worn by receives signals transmitted Bluetooth beacons attached heavy equipment, light vehicles, or dangerous zones, provides visual LED warnings the operators simultaneously. performance test of proposed conducted an underground limestone m...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید