Alkali activated material has recently attracted great attention as an environmentally friendly building material. Generally, it exhibits higher mechanical properties and better durability when compared with Portland cement based materials. In this article, mixed alkali activated systems consisting of N-A-S-H and C-A-S-H hydrated gels were produced, using metakaolin as a dominated starting mate...

Studies on actinobacterial diversity in limestone habitats are scarce. This paper reports profiling of actinobacteria isolated from Hundung limestone samples in Manipur, India using ARDRA as the molecular tool for preliminary classification. A total of 137 actinobacteria were clustered into 31 phylotypic groups based on the ARDRA pattern generated and representative of each group was subjected ...

The effects of a bio-treatment on limestone (here tuffeau) is measured over a large number of dryingimbibition cycles. A model based on a space-dependent permeability coefficient is proposed. It leads to a non-linear diffusion model which accounts for the deviation from the standard Washburn model. Keyword: Limestone, bio-mineralization, water transfer, imbibition, non-linear diffusion

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...

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...

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.

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...

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...

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...

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...