Mechanical Strength of Mortar Made with Binary Fine Aggregates (Dune Sand and Slag Sand)

2010 ◽  
Vol 113-116 ◽  
pp. 639-643
Author(s):  
Laid Baali ◽  
A. Naceri ◽  
Z. Rahmouni ◽  
S. Sekhara
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Mechanical Strength ◽  
Size Distribution ◽  
Sand Dune ◽  
Chemical Characteristics ◽  
Dune Sand ◽  
Fine Aggregates ◽  
Compressive And Flexural Strengths ◽  
Physical And Chemical

Siliceous sand (dune sand) was partially replaced by slag sand (SS) at different proportions (0, 5, 10, 15, 20 and 25%). Using two types of fine aggregates, dune sand (DS) and slag sand (SS), grading, compressive and flexural strengths are measured on mortar. Physical and chemical characteristics of dune sand (DS), slag sand (SS) and cement were determined in this study. The results obtained indicate that the mechanical strength of mortar made with binary sand (DS/SS) depends of the nature and particle size distribution of sand studied.

scholarly journals Investigation of Microbial Contamination and Physicochemical Properties of Compounded Medications in Pharmacies

2020 ◽  
Vol 26 (1) ◽  
pp. 82-93
Author(s):  
Reihaneh Radmanesh ◽  
◽  
Mohsen Nabi Meybodi ◽  
Vahid Ramezani ◽  
Maryam Akrami ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Microbial Contamination ◽  
Raw Materials ◽  
Chemical Properties ◽  
Pharmaceutical Product ◽  
Physical And Chemical ◽  
Made In ◽  
And Chemical Properties

Aims: Any pharmaceutical product made in pharmacy, hospital or factory may be contaminated with microbes. This contamination can originate from raw materials or during production. Hence, it is important to study the physical and chemical properties and stability of compounded drugs. Methods & Materials: In this study, first a specific sample of prescribed medication was ordered from 63 pharmacies in Yazd, Iran. After collecting the samples, the amount of microbial contamination, viscosity and particle size distribution and their stability were investigated and their results were compared to the standard levels. Findings: Based on the results, 31.7% of the samples had discoloration and 23.8% showed creaming phenomenon. In terms of particle size distribution, 57.1% of the samples had a 20-40 μm particle size and 49.2% had a viscosity equal to 2500-3000 centipoise. Regarding stability, 12.6% of the samples underwnet phase change at 30-40°C. About of the amount of hydroquinone in samples, 35% had acceptable amount. In 23.8% of the samples, fungal infection was observed. Conclusion: Contrary to a popular belief that the compounded medicines produced in pharmacies have microbial contamination, the results of this study showed that the microbial contamination of these compounded medications is low.

Physical and chemical characteristics of cryoconites, sampled from glaciers of the Central Caucasus (Russia).

2021 ◽  
Author(s):  
Ivan Kushnov ◽  
Evgeny Abakumov ◽  
Rustam Tembotov ◽  
Viacheslav Polyakov
Keyword(s):  
Particle Size ◽  
Organic Carbon ◽  
Particle Size Distribution ◽  
Solid Phase ◽  
Basal Respiration ◽  
Chemical Characteristics ◽  
Significant Similarity ◽  
Physical And Chemical Characteristics ◽  
Central Caucasus ◽  
Physical And Chemical

<p>Cryoconites are a dark-colored granular sediments found in glacial landscapes. Cryoconites are known as a dark colored accumulation of various origin material in superficial holed of the glaciers which formed in polar and mountain regions of the Earth. They can significantly accelerate glacier retreating by reducing the albedo of the glacier and play a significant role in the colonization of the territory after its retreat, being an "oasis" for development of microorganisms on an uninhabited glacier surface. The understanding of key cryoconites properties is necessary to understand their impact on the mountain glaciers of the Central Caucasus, especially taking into account their recent rapid retreat.</p><p>The aim of this research is to study the physical and chemical characteristics of various cryoconites and cryoconite derived periglacial soils of the Central Caucasus. Eight cryoconite samples and eight soil samples from three soil sections were selected. The following characteristics of the samples were determined in laboratory conditions: total organic carbon (TOC), basal respiration level, pH H<sub>2</sub>O and exchangeable soil acidity, solid phase density and particle size distribution.</p><p>The results of the analyses showed both differences and some similarities in the physical and chemical characteristics of the cryoconites and soils of periglacial zone which were studied. Cryoconites, on average, are characterized by lower values of basal respiration than more developed soils from this region. The total organic carbon content in most samples was relatively low, but its values increase significantly soils investigated due to accumulation of carbon in fine earth under the influence of primary vegetation. The water extractable acidity values showed a significant similarity between the studied cryoconites and soils, they vary from slightly acidic to slightly alkaline in both groups. At the same time, the variation of exchangeable acidity values between cryoconite samples is significantly greater than in developed soils. Moreover, the density of the solid phase of the studied cryoconites varies in a larger range of values than that of the studied soils due to variety of sources of cryoconite materials. However, the analysis of particle size distribution showed a significant similarity of the studied objects: in almost all samples there is a significant dominance of the sand fraction (d=1-0.05 mm). The obtained data indicate both the difference in the physical and chemical properties of the studied cryoconites among themselves, and the probable influence of cryoconites on soil formation in this region.</p><p>This work was supported by Russian Foundation for Basic Research, project No <strong>19-05-50107</strong>  “The role of microparticles of organic carbon in degradation of ice cover of polar regions of the Earths and in the process of soil-like bodies formation”.</p>

MPT Influence on the Rheological Behaviour of Self-Flow Refractory Castables

2008 ◽  
Vol 587-588 ◽  
pp. 133-137 ◽  
Author(s):  
Abílio P. Silva ◽  
Ana M. Segadães ◽  
Tessaleno C. Devezas
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Mechanical Strength ◽  
Size Distribution ◽  
Fine Particles ◽  
Rheological Behaviour ◽  
Response Surfaces ◽  
Coarse Particles ◽  
Aggregate Particle ◽  
Refractory Castables

The success of a refractory castable is largely due to the quality of its properties and ease of application. Self-flow refractory castables (SFRC), with high flowability index (>130%), can be easily accommodated in a mould without the application of external energy, being ideal for the manufacture of monolithic linings. SFRC castables without cement require a matrix of very fine particles, which guarantees improved rheological behaviour and performs the role of the binder in the absence of the refractory cement. The presence of the aggregate (coarse particles) hinders the flowability index, but improves the castable mechanical strength and reduces firing shrinkage, and also contributes to the reduction of the castable costs. The control of the maximum paste thickness (MPT) allows the reduction of the coarse particles interference, minimizing the number of contact points among the grains and avoiding the formation of an aggregate skeleton that impairs the flowability of the mixture. In the present work, 100% alumina SFRCs without cement were produced with a fixed matrix of fine particles, whose particle size distribution was optimized using statistical techniques (mixtures design and triangular response surfaces). Different aggregate particle size distributions were used, with several MPT values, with the objective of evaluating which was the mean distance that maximized the flowability index, simultaneously ensuring good mechanical strength for the refractory castable. Ensuring a minimum surface area of 2.22m2/g, the mixtures reach the self-flow turning point with a minimum water content and the maximum flowability is obtained for an aggregate particle size distribution modulus of q=0.22, and consequently an optimized MPT value. SFRC with high mechanical strength (>60MPa) were obtained.

scholarly journals SILICON CONTENT, PHYSICAL AND CHEMICAL PROPERTIES OF SOILS OF THE KHMELNYTSKY REGION OF UKRAINE

2020 ◽  
pp. 85-90
Author(s):  
O. Tonkha ◽  
O. Bukova ◽  
O. Pikovska ◽  
I. Fedosiy ◽  
O. Menshov ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Humus Content ◽  
Chemical Properties ◽  
Arable Soils ◽  
Silicon Compounds ◽  
Exchangeable Acidity ◽  
Chemical Properties Of Soils ◽  
Physical And Chemical

Silicon plays the significant role in the growth and development of plants, their resistance to stress conditions. However, there is limited research on the content of various forms of silicon in soils, the relationship with soil cations, which is particularly relevant in the context of intensive agriculture and climate aridization in Ukraine. The purpose of the present study was to determine the content of silicon compounds of different mobility in the arable soils of the Khmelnytsky region, the spatial variation of these parameters, and to detect the dependence between the content of silicon compounds and soil particle size. The study was performed at the area of LLC "Lotivka Elit" of Shepetivka district of Khmelnitsky region in field crop rotation. We determined for soil samples: particle size distribution and content of fractions of granulometric elements of different sizes, pH of salt extraction (1,0 M KCl solution), humus content, calcium and magnesium exchangeable compounds by extraction with 1,0 M KCl solution. The results showed that the content of silicon compounds in soils depends on the particle size distribution of soil, the value of exchangeable acidity, humus content, and the composition of exchangeable cations.

The Feasibility Study of Laser Particle Size Analyzer for Thick Pastes

2013 ◽  
Vol 372 ◽  
pp. 428-432
Author(s):  
Shuang Yu Zhang ◽  
Fu Yan Lv ◽  
Zheng Meng Xia ◽  
Na Li ◽  
Miao Wu
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Traditional Method ◽  
Particle Sizes ◽  
Laser Particle Size Analyzer ◽  
Upper Limit ◽  
Particle Size Analyzer ◽  
Coal Slime ◽  
Physical And Chemical

The particle size distribution determines the physical and chemical characteristics of the particle swarm, and then affects rheological properties and transportation resistance characteristics of the thick pastes . Therefore we should find a method to appropriately describe the particle size distribution of thick pastes. Take coal slime to represent, we contrast laser particle size analyzer test with traditional sieving test to find whether the laser particle size analyzer applies to thick pastes or not. The test shows that the laser particle size analyzer which is suitable for the thick pastes to measure their particle sizes. Although its results cant match with the traditional method perfectly, the upper limit particle size can be used as comparison parameter of both methods. In future, the particle size distribution can be directly used, and there is no need to translate it into the sieving particle size distribution.

scholarly journals PHYSICAL, CHEMICAL CHARACTERISTICS AND RELEASE RATE OF MELOXICAM FROM NANOSTRUCTURED LIPID CARRIERS (NLC) SYSTEM USING SOME CONCENTRATION RATIOS OF MONOSTEARIN AND ALPHA TOCOPHEROL ACETATE LIPID MATRIX

2017 ◽  
Vol 10 (2) ◽  
pp. 132
Author(s):  
Yulia Anggraeni ◽  
Isnaeni Isnaeni ◽  
Esti Hendradi
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Entrapment Efficiency ◽  
Nanostructured Lipid Carriers ◽  
Alpha Tocopherol ◽  
Chemical Characteristics ◽  
Lipid Matrix ◽  
Physical And Chemical Characteristics ◽  
Tocopherol Acetate ◽  
Physical And Chemical

Objective: The objective of this research is to develop nanostructured lipid carriers (NLC) of meloxicam (MLX) for topical application using monostearin and alpha-tocopherol as lipid matrix.Methods: MLX-NLC was prepared by high-shear homogenization, and it was characterized for organoleptic, pH, viscosity, particle size and size distribution, zeta potential, crystallinity, morphology, and entrapment efficiency. The six different ratios of solid and liquid lipid matrix were70:30, 75:25, 80:20, 85:15, 90:10, and 95:5, respectively.Results: The pH value of all formulas met the pH range of topical dosage at 4.5-6.5. Viscosity test showed that a trend toward the decrease in viscosity with the increase in alpha-tocopherol content was observed. The results of particle size test proved that all six NLC system formulas have <1000 nm particle size with a quite narrow particle size distribution. Scanning electron microscope revealed nearly spherical shape NLC with negligible effect ratios of solid and liquid lipid on the particle morphology. The X-ray diffraction result showed the decreasing of peaks intensity of MLX-NLC system. It showed that MLX in NLC system is amorphous. The result showed that the increasing concentration of liquid lipid in NLC system caused the rising entrapment efficiency of MLX.Conclusion: The result of this research indicates that the concentration ratio of monostearin and alpha-tocopherol acetate affects the physical and chemical characteristics of NLC system.Keywords: Nanostructured lipid carriers, Meloxicam, Monostearin, Physical and chemical characteristics, Entrapment efficiency. 

scholarly journals REPAIR MODIFIED COMPOSITIONS BASED ON EXPANDING ADDITIVE

2019 ◽  
Author(s):  
Т.С. Муртазаева ◽  
А.А. Узаева ◽  
Д.К. Батаев
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Portland Cement ◽  
Size Distribution ◽  
Sand Dune ◽  
Sand Dunes ◽  
Repair Work ◽  
Mineral Additive ◽  
Expansion Effect

В данной работе представлены результаты исследований, связанные с возможностью эффективного использования некондиционных барханных песков месторождения Шелковское в качестве минеральной добавки для получения тонкомолотых вяжущих и обогащения отсева дробления горных пород. Разработана расширяющаяся добавка, которая при комплексном использовании двуводного гипса с вибромеханохимически активированным вяжущим на барханном песке проявит эффект расширения и предотвратит в дальнейшем усадочные деформации. Полученная расширяющаяся добавка, в состав которой входит портландцемент, барханный песок, суперпластификатор С3 и двуводный гипс позволяет получать ремонтные модифицированные составы с заданной деформацией. Это свойство важно учитывать при производстве ремонтных работ. Доказано, что исследованные барханные пески с характерным минералогическим, химическим и гранулометрическим составом являются эффективным компонентом This paper presents the results of studies related to the possibility of efficient use of substandard sand dunes of the Shelkovskoye deposit as a mineral additive for producing finely ground binders and enriching screening of crushing rocks. An expanding additive has been developed which, when used in combination with twowater gypsum with a vibromechanochemically activated binder on sand dune, will exhibit an expansion effect and prevent further shrinkage deformations. The resulting expanding additive, which includes Portland cement, sand dune, С3 superplasticizer and twowater gypsum, makes it possible to obtain repair modified compounds with a given deformation, it is important to take this property into account when performing repair work. It is proved that the studied sand dunes with a characteristic mineralogical, chemical, and particle size distribution are an effective componen

STUDYING OF THE CHEMICAL COMPOSITION OF THE POWDER FROM BROCCOLI CABBAGE AS RAW MATERIAL FOR PRODUCTION OF FUNCTIONAL FOODS

2019 ◽  
Author(s):  
Т.И. КРЯЧКО ◽  
В.Д. МАЛКИНА ◽  
В.В. МАРТИРОСЯН ◽  
С.А. СМИРНОВА ◽  
Н.А. ГОЛУБКИНА ◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Raw Materials ◽  
Raw Material ◽  
Size Of Particles ◽  
Average Size ◽  
Food Staples ◽  
Physical And Chemical

Представлен сравнительный анализ гранулометрических, органолептических и физико-химических показателей качества порошков из капусты брокколи, полученных конвективным и лиофильным способами сушки из отечественного сорта Тонус и импортного гибрида Маратон F1. По показателям гранулометрического состава исследованные образцы порошков конвективной и лиофильной сушек относятся к грубодисперсным системам. Меньшие значения среднего размера частиц (0,14–0,15 мм) имеют порошки из брокколи гибрида Маратон F1 двух способов сушки. Проведен анализ морфологии частиц порошков из капусты брокколи по характеристикам распределения вытянутости, гладкости и яркости. По гранулометрическому составу и морфологии частиц из порошков капусты брокколи сорта Тонус и гибрида Маратон F1существенных различий не обнаружено. Органолептические показатели – вкус, запах, цвет порошков капусты брокколи сорта Тонус и гибрида Маратон F1соответствовали использованному сырьевому источнику. Содержание белков, жиров и углеводов в порошках, полученных конвективным и лиофильным способами сушки, практически одинаково. Установлена сохранность витамина С в порошках при переработке свежей капусты: сорта Тонус в среднем на 26%, гибрида Маратон F1на 53,5%. Сохранность полифенольных соединений в порошках из брокколи сорта Тонус и гибрида Маратон F1, выработанных двумя способами сушки, составила 57,8–67,8%. Комплексные исследования показали, что порошки из капусты брокколи, выработанные из отечественного и импортного сырья, имеют ценный химический состав, что позволяет отнести их к перспективному продовольственному сырью для использования в технологиях функциональных продуктов питания. The comparative analysis of granulometric, organoleptic and physical and chemical indicators of quality of powders of cabbage of the broccoli received convective and liofilny by ways of drying from a domestic grade the Tonus and an import hybrid Maraton F1is submitted. On indicators of particle size distribution the studied samples of powders of convective and liofilny drying belong to grubodispersny systems. Smaller values of the average size of particles of 0,14–0,15 mm have hybrid broccoli powders Maraton of F1 of two ways of drying. The analysis of morphology of particles of powders of cabbage of broccoli according to characteristics of distribution of elongation, smoothness and brightness is carried out. On particle size distribution and morphology of particles of powders of cabbage of broccoli of a grade the Tonus and a hybrid Maraton F1of essential distinctions isn’t revealed. Organoleptic indicators – taste, a smell, color of powders of cabbage of broccoli of a grade the Tonus and a hybrid Maraton of F1corresponded to the used raw source. Content of proteins, fats and carbohydrates in the powders received convective and liofilny by ways of drying were almost close. The safety of vitamin C in powders when processing fresh cabbage is established: grades the Tonus on average 26%, a hybrid Maraton F1– 53,5%. Safety of polyphenolic connections in grade powders the Tonus and a hybrid Maraton of F1developed on two ways of drying made 57,8–67,8%. Complex researches have shown that the powders of cabbage of broccoli produced from domestic and import raw materials have the valuable chemical composition that allows to carry them to perspective food staples for use in technologies of functional food.

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