scholarly journals Utilization of Jebel Marra Volcanic Ash as Low Cost Material in Concrete Hollow Blocks in Darfur, Sudan

2021 ◽  
Vol 9 (2) ◽  
pp. 28-34
Author(s):  
Najmeldin I. Mohamed ◽  
El-Sharif M. Ibrahiem
Keyword(s):  
Compressive Strength ◽  
Volcanic Ash ◽  
Activity Index ◽  
Low Cost ◽  
Chemical Properties ◽  
Physical Analysis ◽  
Important Place ◽  
Substitution Level ◽  
Fired Bricks ◽  
Physical And Chemical

Concrete hollow blocks (CHB) have an important place in modern building industry, and although the CHB is considered a better alternative to fired bricks from the ecological and economical points of view, however, its prices are still high, since the main cost-factor is the ordinary Portland cement (OPC). This study is mainly focusing on the utilization of volcanic ash (VA) from Jebel Marra as a low cost material for CHB. In this study a VA sample from Jebel Marra (Al-malam area) was investigated for its physical and chemical properties, different substitution levels of 10, 20, 30, 40, and 50% of the OPC with pozzolanas were tested. Combined aggregates of locally available sand and stone aggregates were also tested for their economical value of fineness modulus. Then the potential use of these materials was implemented in (CHB) with different blends and mix ratios. The results of the chemical and physical analysis of the VA showed their compliance to the international specifications. The strength activity index of the mix containing 20%VA of the OPC weight at 28 days was 87%. If consider 3.5 MPa as the minimum compressive strength of load bearing CHB required by the Indian standard, it can be concluded that the VA can be used successfully as low cost material in the CHB with the substitution level up to 40%, 30%, and 20%, for binder aggregates ratio by volume 1:6, 1:7, and 1:8, respectively, with subsequent reduction in binder cost by 34, 26, and 17%, In addition, increasing the compressive strength of blocks can be achieved by using high pressure blocks making machine.  

Effect of Pakistani bentonite on properties of mortar and concrete

Clay Minerals ◽  
2011 ◽  
Vol 46 (1) ◽  
pp. 85-92 ◽  
Author(s):  
S. Ahmad ◽  
S. A. Barbhuiya ◽  
A. Elahi ◽  
J. Iqbal
Keyword(s):  
Experimental Investigation ◽  
Compressive Strength ◽  
Water Demand ◽  
Activity Index ◽  
Low Cost ◽  
Test Results ◽  
Sulphate Attack ◽  
Substitution Level ◽  
Wide Range ◽  
Compressive Strength Of Concrete

AbstractBentonite is composed primarily of montmorillonite and is useful in a wide range of applications. This paper presents the results of an experimental investigation carried out to evaluate the possibility of using a Pakistani bentonite (from Jehangira, Swabi District) as a cement replacement material in mortar and concrete. The cement in mortar and concrete was replaced with the bentonite at 0%, 20%, 30%, 40% and 50% by cement mass. The strength activity index of bentonite was determined ‘as received’ (20ºC) and ‘heated’ (treatment at 500ºC and 900ºC). The test results indicated that the strength activity index of bentonite conformed to the ASTM Standard C618 specifications, except for the ‘900ºC heated’ bentonite. The water absorption decreased for mortar containing up to 30% bentonite and then steadily increased at higher bentonite loadings. When immersed in 5% Na2SO4 and 2% MgSO4 solution, the greatest compressive strength was observed for mortar containing 30% bentonite. The water demand of concrete increased with increasing bentonite content. Although the compressive strength of concrete decreased progressively as the substitution level of bentonite was increased, the compressive strength of concrete containing 30% ‘as received’ bentonite was found to be 70% of the control concrete, whereas for concrete containing 30% ‘500ºC heated’ bentonite, the strength was found to be 79% of the control concrete. It can be concluded that this Pakistani bentonite can be used to replace up to 30% of cement to produce concrete with sufficient compressive strength for low-cost construction resistant to sulphate attack.

scholarly journals Physical and chemical attributes of archaeological soils developed from shell middens in the Região dos Lagos, Rio de Janeiro, Brazil

2011 ◽  
Vol 35 (4) ◽  
pp. 1100-1111 ◽  
Author(s):  
Guilherme Resende Corrêa ◽  
Carlos Ernesto G.R Schaefer ◽  
Vander de Freitas Melo ◽  
Kleberson Worslley de Souza ◽  
João Carlos Ker ◽  
...  
Keyword(s):  
Sandy Loam ◽  
Chemical Properties ◽  
Brazilian Coast ◽  
High Fertility ◽  
Physical Analysis ◽  
Shell Middens ◽  
Organic C ◽  
Chemical Attributes ◽  
Região Dos Lagos ◽  
Physical And Chemical

In prehistoric times, innumerous shell middens, called "sambaquis", consisting mainly of remains of marine organisms, were built along the Brazilian coast. Although the scientific community took interest in these anthropic formations, especially since the nineteenth century, their pedological context is still poorly understood. The purpose of this study was to characterize and identify the physical and chemical changes induced by soil-forming processes, as well as to compare the morphology of shell midden soils with other, already described, anthropogenic soils of Brazil. Four soil profiles developed from shell middens in the Região dos Lagos - RJ were morphologically described and the physical and chemical properties determined. The chemical analysis showed that Ca, Mn, Mg, and particularly P and Zn are indicators of anthropic horizons of midden soils, as in the Amazon Dark Earths (Terras Pretas de Índio). After the deposition of P-rich material, P reaction and leaching can mask or disturb the evidence of in situ man-made strata, but mineralogical and chemical studies of phosphate forms can elucidate the apparent complexity. Lower phosphate-rich strata without direct anthropic inputs indicate P leaching and precipitation in secondary forms. The total and bioavailable contents of Ca, Mg, Zn, Mn, Cu, P, and organic C of midden soils were much higher than of regional soils without influence of ancient human settlements, demonstrating that the high fertility persisted for long periods, at some sites for more than 4000 years. The physical analysis showed that wind-blown sand contributed significantly to increase the sand fraction in the analyzed soils (texture classes sand, sandy loam and sandy clay loam) and that the aeolian sand accumulation occurred simultaneously with the midden formation.

scholarly journals Some physical and chemical properties of substrates designed for container production of spruce (Picea abies (L) Karst)

2004 ◽  
pp. 79-90
Author(s):  
Vesna Vratusa
Keyword(s):  
Woody Plants ◽  
Low Cost ◽  
Chemical Properties ◽  
Foreign Markets ◽  
Urban Green Spaces ◽  
Nursery Production ◽  
Countries In Transition ◽  
Physical And Chemical ◽  
And Chemical Properties

Efficient nursery production of woody plants, as well as the level of their successful application in urban green spaces, greatly depends upon properties of substrates in which these individuals grow, develop and endure. Furthermore, quality of substrate does not only affect the quality of future product (plant individual or green space), but distinctly determines its price. This element, extremely significant for all countries in transition, thus Serbia as well, commands finding ways of making qualitative, but least expensive substrate. The most logical solution is to use mixtures/substrates of precisely defined properties, composed of domestic components. Results presented in this paper imply that it is possible to create precisely such standard mixtures from domestic resources at relatively low cost, adjusted to needs of particular species, which would ultimately lead to successful, non-expensive nursery production and application of produced stock, both on domestic and foreign markets.

scholarly journals M-Polynomials and Associated Topological Indices of Sodalite Materials

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ghazanfar Abbas ◽  
Muhammad Ibrahim ◽  
Ali Ahmad ◽  
Muhammad Azeem ◽  
Kashif Elahi
Keyword(s):  
Greenhouse Gases ◽  
Topological Index ◽  
Low Cost ◽  
Chemical Properties ◽  
Topological Indices ◽  
Mathematical Tool ◽  
Physical And Chemical Properties ◽  
Natural Zeolites ◽  
Physical And Chemical ◽  
And Chemical Properties

Natural zeolites are commonly described as macromolecular sieves. Zeolite networks are very trendy chemical networks due to their low-cost implementation. Sodalite network is one of the most studied types of zeolite networks. It helps in the removal of greenhouse gases. To study this rich network, we use an authentic mathematical tool known as M-polynomials of the topological index and show some physical and chemical properties in numerical form, and to understand the structure deeply, we compare different legitimate M-polynomials of topological indices, concluding in the form of graphical comparisons.

scholarly journals Basic Materials Studies of Lanthanide Halide Scintillators

2007 ◽  
Vol 1038 ◽  
Author(s):  
F. P. Doty ◽  
Douglas McGregor ◽  
Mark Harrison ◽  
Kip Findley ◽  
Raulf Polichar ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Materials Science ◽  
Low Cost ◽  
Large Diameter ◽  
Scale Up ◽  
Chemical Properties ◽  
Anisotropic Plasticity ◽  
Ongoing Work ◽  
Perfect Cleavage ◽  
Physical And Chemical

AbstractCerium and lanthanum tribromides and trichlorides form isomorphous alloys with the hexagonal UCl3 type structure, and have been shown to exhibit high luminosity and proportional response, making them attractive alternatives for room temperature gamma ray spectroscopy. However the fundamental physical and chemical properties of this system introduce challenges for material processing, scale-up, and detector fabrication. In particular, low fracture stress and perfect cleavage along prismatic planes cause profuse cracking during and after crystal growth, impeding efforts to scale this system for production of low cost, large diameter spectrometers. We have reported progress on basic materials science of the lanthanide halides. Studies to date have included thermomechanical and thermogravimetric analyses, hygroscopicity, yield strength, and fracture toughness. The observed mechanical properties pose challenging problems for material production and post processing; therefore, understanding mechanical behavior is key to fabricating large single crystals, and engineering of robust detectors and systems. Analysis of the symmetry and crystal structure of this system, including identification of densely-packed and electrically neutral planes with slip and cleavage, and comparison of relative formation and propagation energies for proposed slip systems, suggest possible mechanisms for deformation and crack initiation under stress. The low c/a ratio and low symmetry relative to traditional scintillators indicate limited and highly anisotropic plasticity cause redistribution of residual process stress to cleavage planes, initiating fracture. Ongoing work to develop fracture resistant lanthanide halides is presented.

Degradation of Colored Polystyrene Films

2018 ◽  
Vol 930 ◽  
pp. 254-257 ◽  
Author(s):  
Francisca Pereira de Araújo ◽  
Josy Anteveli Osajima ◽  
Mônica Regina Silva de Araujo ◽  
Edson Cavalcanti da Silva Filho ◽  
João Sammy Nery de Souza
Keyword(s):  
Crystal Violet ◽  
Carbonyl Compounds ◽  
Low Cost ◽  
Chemical Properties ◽  
Polymer Materials ◽  
Visible Radiation ◽  
No Formation ◽  
Crystal Violet Dye ◽  
Physical And Chemical ◽  
And Chemical Properties

Polystyrene is commercial polymer of extensive use in industrial scale due to great physical and chemical properties and low cost. Lifespan of polymer materials can be changed by incorporation of additions to polymeric matrix.The present study aimed to evaluate the influence of crystal violet dye in polystyrene matrices when irradiated by visible radiation. The samples were studied in the form of films, in which solution of crystal violet (5.0x10-4mol.L-1) was added to the PS solution (8% w / w). The films were irradiated with commercial lamp for 150 hours and analyzed with UV-Vis and FTIR. The results showed that the dye degraded at a rate of 16%, however the FTIR analysis revealed that polystyrene did not degrade under the conditions studied, since no formation of carbonyl compounds was observed.

scholarly journals Chitosan–Starch Films Modified with Natural Extracts to Remove Heavy Oil from Water

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 17
Author(s):  
Jessica I. Lozano-Navarro ◽  
Nancy P. Díaz-Zavala ◽  
José A. Melo-Banda ◽  
Carlos Velasco-Santos ◽  
Francisco Paraguay-Delgado ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Heavy Oil ◽  
Low Cost ◽  
Chemical Properties ◽  
Clear Correlation ◽  
Natural Extracts ◽  
Water Ph ◽  
Starch Films ◽  
Gas Chromatography Mass Spectroscopy ◽  
Physical And Chemical

Chitosan films were used to remove heavy oil from connate water, deionized water, and seawater. In this research, chitosan–starch films were modified with natural extracts from cranberry, blueberry, beetroot, pomegranate, oregano, pitaya, and grape. These biodegradable, low-cost, eco-friendly materials show an important oil sorption capacity from different water conditions. It was observed that the sorption capacity has a clear correlation with the extract type, quantity, and water pH. In order to understand the physical and chemical properties of the films, they were analyzed according to their apparent density, water content, solubility, and swelling degree by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), gas chromatography–mass spectroscopy (GC–MS), and the determination of surface area using the Brunauer Emmett Teller (BET) method. The results indicate that chitosan–starch films modified with natural extracts can be successfully applied for environmental issues such as oil spill remedy.

Allophane and imogolite: role in soil biogeochemical processes

Clay Minerals ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 135-155 ◽  
Author(s):  
R. L. Parfitt
Keyword(s):  
Organic Matter ◽  
Plant Material ◽  
Volcanic Ash ◽  
Forest Biomass ◽  
Chemical Properties ◽  
Young Forests ◽  
Labile P ◽  
Physical And Chemical ◽  
By Products ◽  
And Chemical Properties

AbstractThe literature on the formation, structure and properties of allophane and imogolite is reviewed, with particular emphasis on the seminal contributions by Colin Farmer. Allophane and imogolite occur not only in volcanic-ash soils but also in other environments. The conditions required for the precipitation of allophane and imogolite are discussed. These include pH, availability of Al and Si, rainfall, leaching regime, and reactions with organic matter. Because of their excellent water storage and physical properties, allophanic soils can accumulate large amounts of biomass. In areas of high rainfall, these soils often occur under rain forest, and the soil organic matter derived from the forest biomass is stabilized by allophane and aluminium ions. Thus the turnover of soil organicmatter in allophanicsoils is slower than that in non-allophanicsoils. The organic matter appears to be derived from the microbial by-products of the plant material rather than from the plant material itself. The growth of young forests may be limited by nitrogen supply but growth of older forests tends to be P limited. Phosphorus is recycled through both inorganic and organic pathways, but it is also strongly sorbed by Al compounds including allophane. When crops are grown in allophanic soils, large amounts of labile P are required and, accordingly, these soils have to be managed to counteract the large P sorption capacity of allophane and other Al compounds, and to ensure an adequate supply of labile P. Because of their physical and chemical properties, allophanic soils are excellent filters of heavy metals and pathogens.

scholarly journals Sustainable low-carbon binders and concretes

2020 ◽  
Vol 166 ◽  
pp. 06007
Author(s):  
Myroslav Sanytsky ◽  
Tetiana Kropyvnytska ◽  
Stanislav Fic ◽  
Hanna Ivashchyshyn
Keyword(s):  
Activity Index ◽  
Chemical Properties ◽  
High Volume ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Cement Matrix ◽  
Low Carbon ◽  
Blended Cements ◽  
Physical And Chemical

Sustainable development depends on a consistency of interests, social, ecological and economic, and that the interests are evaluated in a balanced manner. In order to reduce CO2 emissions, the conception of decreasing clinker factor and increasing the role of supplementary cementitious materials (SCMs) in the cementitious materials has high economical and environmental efficiency. The performance of clinkerefficient blended cements with supplementary cementitious materials were examined. The influence of superfine zeolite with increased surface energy on the physical and chemical properties of low-carbon blended cements is shown. Increasing the dispersion of cementitious materials contributes to the growth of their strength activity index due to compaction of cement matrix and pozzolanic reactions in unclincker part. In consequence of the early structure formation and the directed formation of the microstructure of the cement matrix is solving the problem of obtaining clinker-efficient concretes. Shown that low-carbon blended cements with high volume of SCMs are suitable, in principle, for producing structural concretes.

Study the Effects of Different Surfactants on Hydrophilicity of Polydimethylsiloxane (PDMS)

2012 ◽  
Author(s):  
Hojjat Madadi ◽  
Jasmina Casals-Terré
Keyword(s):  
Vapour Deposition ◽  
Low Cost ◽  
Chemical Vapour ◽  
Chemical Properties ◽  
Base Material ◽  
Hydrophobic Surface ◽  
Fabrication Procedure ◽  
Highly Hydrophobic ◽  
Physical And Chemical ◽  
And Chemical Properties

The outstanding characteristics of polydimethylsiloxane (PDMS) caused its extensive use as base material to manufacture microfluidic devices. PDMS has numerous advantages coming from instinct properties such as its low cost, simple fabrication procedure, and robust nature that make it a compatible material in many applications such as biological and biomedical engineering. In spite of favorable physical and chemical properties, hydrophobic surface of PDMS is sometimes debatable. Because of PDMS is highly hydrophobic, pumping aqueous solution through microchannels using only capillary forces might be difficult. Although many surface treatments methods have been proposed to modify and increase the hydrophilicity of PDMS [Oxygen plasma [1], UV-radiation [2], Silanization and Chemical vapour deposition [3],…], the use of surfactants is the most effective and easiest method to overcome the hydrophobicity compared to more complex protocols which require expensive facilities [4,5]. The hydrophilic behavior of surfactant-added PDMS and especially its biocompatibility has allowed many microfluidic bio-applications such as separation of biomolecules [6,7], blood cell separation [8] and cell-based assay [9,10]. This paper discusses about the efficiency of adding different surfactants on the wettability of PDMS.

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