Comparative Evaluation of Potential Impacts of Agricultural and Industrial Waste Pozzolanic Binders on Strengths of Concrete

Concrete is one of the most widely used construction material in the world which uses aggregates and cement as a binder. Use of cement concrete and mining/ transportation of raw materials makes the construction industry the biggest emitter of CO2 by contributing up to 7-10% of global emissions. The waste materials from different industries and agriculture contribute to 90% of waste disposal/ recycling effort in the world. This research has focused to use a selection of waste materials as supplementary cementitious materials (SCM) to minimize the emission of CO2 and recycling/ absorption of waste from other industries to construction industry to make it more sustainable. The contemporary research has established use of pulverized fly ash (PFA), silica fume (SF), metakaolin (MK) and granulated ground blast furnace slag (GGBS) as suitable SCMs. This study has focused on using two established industrial waste SF and MK and two agricultural wastes, rice husk ash (RHA) and palm ash (PA), to determine and compare their potential use as pozzolanic SCMs and to expand the family of alternative pozzolanic binders in addition to PFA and GGBS. The w/c (w/b) ratio was 0.4 with an intended design mix strength classification of C50/60. The chemical composition of all the materials was determined through x-ray spectrometry/ diffraction test to ascertain the chemistry. All four materials satisfied the ASTM constituent criteria for pozzolans. In comparison to the control mix (100% cement content), all these materials improved the compressive strength from 2.5% to 30% and enhanced tensile strength from up to 17%, indeed all the SCM mixes had a higher compressive strength than the control. RHA exhibited the best performance in agricultural waste with 10% optimum quantity to give maximum compressive strength of 83 MPa and PA exhibited the optimum performance with 2.5% content and gave maximum compressive strength of 78 MPa. The addition of MK progressively increased the compressive strength with 20% content mix giving a strength of 84 MPa. The SF performed the best at optimum quantity of 2.5% and exhibited the highest compressive strength of 90 MPa. The results suggest that these SCM based concrete are recommended for formulation of high-strength concrete applications, i.e., 60+ MPa. Furthermore, all the SCMs had at least one mix which satisfied the C60/75 classification without reducing the w/b ratio below 0.4; this has significant positive ramifications for the development of sustainable high-performance concrete. The absorption of waste materials from industrial and agricultural fields can substantially reduce waste disposal and more pertinently facilitate in reducing the CO2 emission associated with the construction industry

Production of oxalic acid from sawdust using coal fly ash as a catalyst

The production of oxalic acid from sawdust using a mixture of strong nitric acid and concentrated sulphuric acid with coal fly ash as a catalyst has been explored. Operating parameters affecting the reaction were determined to be temperature, mesh size and amount of fly ash catalyst, time and the $${\text{HNO}}_{3} :{\text{H}}_{2} {\text{SO}}_{4}$$ HNO 3 : H 2 SO 4 ratio. A maximum oxalic acid yield of 84% was obtained using a mixture of 60% $${\text{HNO}}_{3} {\text{ and }}40 \%{\text{ H}}_{2} {\text{SO}}_{4}$$ HNO 3 and 40 % H 2 SO 4 at 70 °C and a reaction time of 150 minutes. Coal fly ash with particle size of 50–100 μm proved to be a suitable and efficient catalyst, and the optimum quantity of catalyst employed was 5g of fly ash for every 100g of sawdust.

An Experimental Investigation of Expansive Soil Treated with Glass powder and Granite Dust

In urban areas, borrow earth is not easily available which has to be hauled from a long distance. Quite often, large areas are covered with highly plastic and expansive soil, which is not suitable for such purpose. This study involves the collection of clay sample and evaluation of its properties in natural state and after stabilization with Granite dust and Glass powder. In the first set of experimental work the BC soil is mixed with Glass powder in different proportion i.e. 2%,4%,6%,8% and 10% and the optimum quantity of Glass powder is determined. The optimum quantity of Glass powder is found as 8% of the dry weight of clay. In the second set of experimental work the BC soil is stabilized by Glass powder and Granite dust in combination. Granite dust used 10-20 % of the dry weight of clay with Glass powder additives. From the experimental study it can be concluded that the stabilization of BC soil with Granite dust and Glass powder is more effective as compared to the stabilization with Glass powder only.

Polyamines: Functions, Metabolism, and Role in Human Disease Management

Putrescine, spermine, and spermidine are the important polyamines (PAs), found in all living organisms. PAs are formed by the decarboxylation of amino acids, and they facilitate cell growth and development via different cellular responses. PAs are the integrated part of the cellular and genetic metabolism and help in transcription, translation, signaling, and post-translational modifications. At the cellular level, PA concentration may influence the condition of various diseases in the body. For instance, a high PA level is detrimental to patients suffering from aging, cognitive impairment, and cancer. The levels of PAs decline with age in humans, which is associated with different health disorders. On the other hand, PAs reduce the risk of many cardiovascular diseases and increase longevity, when taken in an optimum quantity. Therefore, a controlled diet is an easy way to maintain the level of PAs in the body. Based on the nutritional intake of PAs, healthy cell functioning can be maintained. Moreover, several diseases can also be controlled to a higher extend via maintaining the metabolism of PAs. The present review discusses the types, important functions, and metabolism of PAs in humans. It also highlights the nutritional role of PAs in the prevention of various diseases.

MATHEMATICAL MODEL OF SUBSTANTIATION OF THE GEOLOGICAL AND COMMERCIAL STRUCTURE FOR CONDUCTING TRIAL OPERATION AT THE “ZHANATALAP” PRODUCTION FIELD

The relevance of the problem stated in the paper is conditioned by fact that in the last decade, scientific and technological progress in the sphere of petroleum field geology was closely related to the use of advanced science-intensive geoinformational technologies based on modern database management systems. In this regard, the paper considers the general principles of constructing systems for geological and commercial field analysis and oil fields development regulation. The main goal of trial operation is to obtain direct information about the production capabilities of project sites and their geological and geophysical characteristics, sufficient to justify the optimum quantity of recoverable oil reserves and ensure effective reservoir and production engineering, as well as substantiation of the reservoir regime, identification of production facilities and assessment of the prospects for the development of oil production at the field. The leading method of this issue is the substantiation of a geologic model, which allows us to consider this problem as a purposeful and organised modelling method to improve the conduct of trial operation in the Aptian and Middle Jurassic productive horizons. The results of pressure transient analysis were obtained. The terms of trial operation and the volumes of oil production, average daily withdrawals are substantiated, the issues of equipment and technology of oil production, drilling and well development are considered.

Treatment of Secondary Dust Produced in Rotary Hearth Furnace through Alkali Leaching and Evaporation–Crystallization Processes

This paper presents the results of an experimental study on the extraction of KCl and the improvement of the zinc grade of secondary dust obtained from rotary-hearth-furnace secondary dust (RHF secondary dust) using alkali leaching (Na2CO3 solution) and evaporation–crystallization processes. The effects of the liquid–solid ratio and Na2CO3 content on the element leaching ratio in the alkali leaching process, as well as the effects of the volume–evaporation ratio and cooling temperature on KCl extraction in the evaporation–crystallization process, were investigated. The results showed that the optimum liquid–solid ratio was 6:1, and the optimum quantity of Na2CO3 was 1.5 times the basic quantity. The recovery ratio of zinc reached 95.23%, and the leaching ratio of K reached 79.01%. The experimental results of the evaporation–crystallization process demonstrated that the evaporation temperature was 80 °C, the volume evaporation ratio was 50%, the cooling temperature was 25 °C, and the mass fraction of K2O in the obtained crystals was 58.99%.

A surprising mechanism lacking the Ni(0) state during the Ni(II)-catalyzed P–C cross-coupling reaction performed in the absence of a reducing agent – An experimental and a theoretical study

The Hirao reaction, i.e. the P–C coupling between a bromoarene and a >P(O)H reagent performed in most cases in the presence of a Pd(0) complex incorporating a P-ligand may also be carried out applying a Ni(II) catalyst precursor with or without Zn or Mg as the reducing agent. The Ni catalysts may include P- or N-ligands. B3LYP/6-31G(d,p)//PCM(MeCN) quantum chemical calculations suggested that the mechanism of the NiX2 catalyzed (X=Cl or Br) P–C couplings performed in the absence of a reducing agent, and in the excess of the >P(O)H reagent serving as the P-ligand (via its tautomeric >POH form) is completely different from that of the Pd(OAc)2 promoted version, as no reduction of the Ni(II) occurs. In the two variations mentioned, the active catalyst is the dehydrobrominated species derived from primary complex [(HO)Y2P]2Ni(II)Br2, and the [(HO)Y2P]2Pd(0) complex itself, respectively. Both species undergo temporary oxidation (to “Ni(IV)” and “Pd(II)”, respectively) in the catalytic cycle. During the catalysis with “P2Ni(II)X2”, one of the P-ligands serves the >P(O)H function of the ArP(O)H < product. The consequence of this difference is that in the Ni(II)-catalyzed case, somewhat less >P(O)H-species is needed than in the Pd(0)-promoted instance. Applying 10 % of the Pd(OAc)2 or NiX2 precursor, the optimum quantity of the P-reagent is 1.3 equivalent and, in the first approach, 1.1 equivalent, respectively. Preparative experiments justified the new mechanism explored. The ligation of Ni(II) was also investigated by theoretical calculations. It was proved that the bis-complexation is the most favorable energetically as compared to the mono-, tri- and tetra-ligation.

Exploring optimum percentage of fly-ash as a replacement of cement for enhancement of concrete properties

Researchers and decision makers are continuously looking out to determine the potential and effectiveness of fly-ash as a partial replacement of cement in concrete. The current study is carried out to check the optimum or nearly optimum quantity of fly-ash with which cement should be replaced to get most of the properties of concrete enhanced and to give the idea about the quantities of fly-ash that can be used in a better way and better cause so that a proper management scheme of its usage and disposal can be implied. Further, a comparison is given between normal concrete and fly-ash concrete to show the properties which can be enhanced by proper utilization of fly-ash as a partial replacement of cement. After carrying out the lab experiments, it has been seen that the replacement of fly-ash in concrete has resulted in general increase in compressive strength, flexural strength and splitting tensile strength up to 15% replacement and after then the strength is decreased considerably than that of normal concrete. Addition of fly-ash in concrete has resulted in decrease in the water absorption of concrete and hence decreases in permeability of concrete. There is a progressive increase in workability with increase in percentage of fly-ash in concrete. The current study has led to a conclusion that in order to achieve best results in use of fly-ash concrete, the fly-ash used for replacing cement in concrete should have the required properties as specified by the standards and proper techniques of processing fly-ash as well as mixing of fly-ash with cement must be employed.

AN EXPERIMENTAL RESEARCH REGARDING THE OPTIMUM COMPOSITION FOR WOOD SLAG BOARDS

Wood slag boards (WSB) belong to the group of composites formed on the basis of mineral binders (cement, gypsum, blast-slag, etc.). They are multi-componential systems consisting of wood particles, slag-alkaline and mineralizator. The physico-mechanical properties of WSB completely answer the standard requirements valid for high-density wood-cement boards and therefore can be used as a competitive building material. The economic relevancy of their production is grounded in providing building industry with high-quality and at the same time cheap materials, as well as in utilizing scrap materials which would otherwise pollute the environment (blast slag and scrap wood). The optimizing of the mass parts of the components of WSB is a very important problem both from technological and economical point of view. The success in solving the optimizing problem depends to a great degree on the choice of method. This is way a planned experiment is applied, based on the simplex method for multicomponent system with preliminarily determined limits of calculation of the factors. With the help of specialized computer software, the optimum quantity of the components is determined through graphically presented optimum areas