An Experimental Study of Strengthing of Concrete by Bacterial Mineral Precipitation

A new technique in remediating cracks and fissures in concrete by utilizing microbiologically induced Calcite (CaCo3) precipitation is discussed. Microbiologically induced calcite precipitation (MICP) is a technique that comes under a broader category of science called Bio Mineralization. It is a process by which living organisms form inorganic solids. Bacillus subtilis, a common soil bacterium can induce the precipitation of calcite. The objective of the present investigation is to study the potential application of bacterial species i.e. Bacillus subtilis to improve the strength of cement concrete. Here we have made an attempt to incorporate dormant but viable bacteria in the concrete matrix which will contribute to the strength of the concrete. In this project, bacterial concrete is prepared under grade of concrete M30.The design mix proportioning also carried under IS code provision. Testing of specimens are carried at 7 days, 14 days and 28 days of curing by Compression Testing Machine and Universal Testing Machine for corresponding specimens.

Energy landscapes of perfect and defective solids: from structure prediction to ion conduction

The energy landscape concept is increasingly valuable in understanding and unifying the structural, thermodynamic and dynamic properties of inorganic solids. We present a range of examples which include (i) structure prediction of new bulk phases including carbon nitrides, phosphorus carbides, LiMgF3 and low-density, ultra-flexible polymorphs of B2O3, (ii) prediction of graphene and related forms of ZnO, ZnS and other compounds which crystallise in the bulk with the wurtzite structure, (iii) solid solutions, (iv) understanding grossly non-stoichiometric oxides including the superionic phases of δ-Bi2O3 and BIMEVOX and the consequences for the mechanisms of ion transport in these fast ion conductors. In general, examination of the energy landscapes of disordered materials highlights the importance of local structural environments, rather than sole consideration of the average structure.

Development of Efficient and Selective Processes for the Synthesis of Commercially Important Chlorinated Phenols

para-Selective processes for the chlorination of phenols using sulphuryl chloride in the presence of various sulphur-containing catalysts have been successfully developed. Several chlorinated phenols, especially those derived by para-chlorination of phenol, ortho-cresol, meta-cresol, and meta-xylenol, are of significant commercial importance, but chlorination reactions of such phenols are not always as regioselective as would be desirable. We, therefore, undertook the challenge of developing suitable catalysts that might promote greater regioselectivity under conditions that might still be applicable for the commercial manufacture of products on a large scale. In this review, we chart our progress in this endeavour from early studies involving inorganic solids as potential catalysts, through the use of simple dialkyl sulphides, which were effective but unsuitable for commercial application, and through a variety of other types of sulphur compounds, to the eventual identification of particular poly(alkylene sulphide)s as very useful catalysts. When used in conjunction with a Lewis acid such as aluminium or ferric chloride as an activator, and with sulphuryl chloride as the reagent, quantitative yields of chlorophenols can be obtained with very high regioselectivity in the presence of tiny amounts of the polymeric sulphides, usually in solvent-free conditions (unless the phenol starting material is solid at temperatures even above about 50 °C). Notably, poly(alkylene sulphide)s containing longer spacer groups are particularly para-selective in the chlorination of m-cresol and m-xylenol, while, ones with shorter spacers are particularly para-selective in the chlorination of phenol, 2-chlorophenol, and o-cresol. Such chlorination processes result in some of the highest para/ortho ratios reported for the chlorination of phenols.

Techniques for Reducing Iron (Fe) Content in Groundwater: an Article Review

Iron is a chemical element that is found in almost every place on earth, including in well water or groundwater. Iron can be suspended in water with organic substances or inorganic solids in the form of ferrous cations (Fe2+) and ferries (Fe3+). The presence of iron that exceeds the threshold can cause detrimental effects such as corrosion of the piping, the color of the water turns brown, smells bad, and can cause health problems. The iron content in groundwater can be reduced so that it can be used as water that is fit for consumption or use in everyday life. This study aims to determine several types of techniques used to reduce iron in groundwater or well water through literature studies. Techniques covered include filtration, aeration, adsorption, coagulation, electrocoagulation, and cascade aerators. The results showed that the greatest reduction in efficiency was found in the combination type of adsorption technique and filtration technique by more than 99.1%, then followed by the electrocoagulation technique of 99.74%. From all the techniques studied in this study, it can be concluded that all techniques can reduce iron levels in which the combination of adsorption and filtration techniques is the most effective.Keywords: Technique, reduction, iron content, groundwater

Porous Silica-Based Organic-Inorganic Hybrid Catalysts: A Review

Hybrid organic-inorganic catalysts have been extensively investigated by several research groups in the last decades, as they allow combining the structural robust-ness of inorganic solids with the versatility of organic chemistry. Within the field of hybrid catalysts, synthetic strategies based on silica are among the most exploitable, due to the convenience of sol-gel chemistry, to the array of silyl-derivative precursors that can be synthesized and to the number of post-synthetic functionalization strategies available, amongst others. This review proposes to highlight these advantages, firstly describing the most common synthetic tools and the chemistry behind sol-gel syntheses of hybrid catalysts, then presenting exemplificative studies involving mono- and multi-functional silica-based hybrid catalysts featuring different types of active sites (acid, base, redox). Materials obtained through different approaches are described and their properties, as well as their catalytic performances, are compared. The general scope of this review is to gather useful information for those approaching the synthesis of organic-inorganic hybrid materials, while providing an overview on the state-of-the art in the synthesis of such materials and highlighting their capacities.

Proton-detected fast-magic-angle spinning NMR of paramagnetic inorganic solids

Fast magic-angle spinning NMR allows rapid fingerprinting of paramagnetic organometallic complexes in powder form.