scholarly journals Research of physical and chemical processes associated with corrosion of cements (“Caking”) in dampy wet air

2021 ◽  
Vol 48 (2) ◽  
pp. 103-112
Author(s):  
A. A. Krutilin ◽  
T. V. Krapchetova ◽  
N. A. Inkova ◽  
O. K. Pakhomova
Keyword(s):  
Storage Conditions ◽  
Surface Layers ◽  
Chemical Methods ◽  
Storage Duration ◽  
Adsorption Of Water ◽  
Mechanism And Kinetics ◽  
Physical And Chemical ◽  
Kinetics Of ◽  
Adsorption Of Water Vapor ◽  
Kinetics Of Sorption

Objective. The paper is aimed at clarifying the mechanism and kinetics of the processes leading to cement caking. Methods. To determine phase composition, the following modern physical and chemical methods were used: XRF, derivatography and electron microscopy. Results. The data obtained show that the “aging” of cements during their forced storage in humid air through the adsorption of water vapor, and then CO2, is associated with the processes of hydrolysis, hydration in surface layers of particles, is primarily relevant for the most reactive minerals of Portland cement clinker. The deepening of these processes also depends on the state of the corroded surface of minerals. Conclusion. The work carried out makes it is possible to preliminarily outline storage conditions for freshly ground Portland cements (according to the kinetics of sorption – the storage duration, according to isotherms – the permissible relative humidity), at which the LOI value of commercial cement remains stable for the required minimum time.

SUBSTANTIATION OF THE TECHNOLOGICAL SCHEME FOR PRODUCING LIQUID SUGAR FROM SEMI-PRODUCTS OF BEET SUGAR PRODUCTION

2019 ◽  
Author(s):  
Р.С. Решетова ◽  
О.Ю. Бганцева
Keyword(s):  
Food Production ◽  
Technological Scheme ◽  
Preliminary Treatment ◽  
Sugar Solution ◽  
Sugar Production ◽  
Chemical Methods ◽  
Storage Duration ◽  
Number Of Microorganisms ◽  
Permissible Levels ◽  
Physical And Chemical

Разработана технологическая схема получения жидкого сахара из полупродуктов свеклосахарного производства, которая предусматривает получение исходного (концентрированного) сахарного раствора из сиропа после выпарки, некондиционного сахара и желтого сахара последнего продукта с содержанием сухих веществ (СВ) от 68 до 72. Изучено изменение количества микроорганизмов в жидком сахаре в течение 30 сут хранения в закрытых сосудах при температуре окружающей среды без предварительной обработки физическим и химическим способами с целью использования сиропа при производстве пищевых продуктов. Установлено, что в растворе с содержанием СВ 68 72 количество микроорганизмов увеличилось: бактерий с 15 до 60 КОЕ/г, дрожжей и плесневых грибов с 10 до 34 КОЕ/г, что не превышает допустимых уровней СанПиН 2.3.2.1078 01 и ГОСТ Р 53035 2008. Определена длительность хранения жидкого сахара для использования в пищевых производствах не более 15 сут. The technological scheme of obtaining liquid sugar from semiproducts of sugar beet production, which provides for obtaining the initial (concentrated) sugar solution from the syrup after evaporation, substandard sugar and yellow sugar of the last product with a content of dry matters from 68 to 72, has been developed. The change in the number of microorganisms in liquid sugar was studied during 30 days of storage in closed vessels at ambient temperature without preliminary treatment by physical and chemical methods with the aim of using syrup in food production. It was found that in the solution with the content of dry matters 68 72 the number of microorganisms increased: bacteria from 15 to 60 CFU/g, yeast and fungi from 10 to 34 CFU/g, which does not exceed the permissible levels of SanPiN 2.3.2.1078 01 and GOST R 53035 2008. The storage duration of liquid sugar for use in food production was determined no more than 15 days.

OBSERVATIONS ON THE ADSORPTION OF WATER VAPOR BY WHEAT

1949 ◽  
Vol 27f (2) ◽  
pp. 55-72 ◽  
Author(s):  
J. D. Babbitt
Keyword(s):  
Water Vapor ◽  
Storage Conditions ◽  
Adsorption And Desorption ◽  
Adsorption Of Water ◽  
Time Required ◽  
Adsorption Of Water Vapor

The adsorption and desorption of water vapor by wheat was measured by means of a McBain sorption balance. Curves are obtained showing the rate at which moisture is adsorbed by kernels of wheat directly exposed to a humidified atmosphere, and a theory is advanced to account for the rate of adsorption. It is shown that the rate of adsorption is governed largely by the time taken for the moisture to diffuse up to the surface of the wheat. Under storage conditions, this is much greater than the time required for the moisture to penetrate the kernel of wheat from its surface.

Oil extraction from the sunflower seeds, mechanism and kinetics of the process

2020 ◽  
Vol 3 (1) ◽  
pp. 155-160
Author(s):  
Ye. M. Semenyshyn ◽  
◽  
V. M. Atamanyuk ◽  
O. Ya. Dobrovetska ◽  
T. I. Rymar ◽  
...  
Keyword(s):  
Oil Extraction ◽  
Sunflower Seeds ◽  
Mechanism And Kinetics ◽  
Kinetics Of

Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

2018 ◽  
Vol 69 (5) ◽  
pp. 1139-1144
Author(s):  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Livia Carmen Ungureanu ◽  
Valerica Stanoi ◽  
Traian Rus
Keyword(s):  
Structural Changes ◽  
Oxidation Processes ◽  
High Oleic ◽  
Painting Materials ◽  
Insulating Paper ◽  
Different Types ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Natural Ester

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.

Modification of Collagen for Biomedical Applications: A Review of Physical and Chemical Methods

2016 ◽  
Vol 20 (17) ◽  
pp. 1797-1812 ◽  
Author(s):  
Xiaoyue Yu ◽  
Cuie Tang ◽  
Shanbai Xiong ◽  
Qijuan Yuan ◽  
Zhipeng Gu ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Chemical Methods ◽  
Physical And Chemical

Biomedical Applications and Patents on Metallic Nanoparticles

2020 ◽  
Vol 10 ◽  
Author(s):  
Geetanjali Singh ◽  
Pramod Kumar Sharma ◽  
Rishabha Malviya
Keyword(s):  
Metallic Nanoparticles ◽  
Biomedical Applications ◽  
Size Range ◽  
Biomedical Application ◽  
Chemical Reduction ◽  
Chemical Methods ◽  
Future Challenges ◽  
Biological Methods ◽  
Cancer Diagnosis And Therapy ◽  
Physical And Chemical

Aim/Objective: The author writes the manuscript by reviewing the literatures related to the biomedical application of metallic nanoparticles. The term metal nanoparticles are used to describe the nanosized metals with the dimension within the size range of 1-100 nm. Methods: The preparation of metallic nanoparticles and their application is an influential area for research. Among various physical and chemical methods (viz. chemical reduction, thermal decomposition, etc.) for synthesizing silver nanoparticles, biological methods have been suggested as possible eco-friendly alternatives. The synthesis of metallic nanoparticles is having many problems inclusive of solvent toxicity, the formation of hazardous byproducts and consumption of energy. So it is important to design eco-friendly benign procedures for the synthesis of metallic nanoparticles. Results: From the literature survey, we concluded that metallic nanoparticles have applications in the treatment of different diseases. Metallic nanoparticles are having a great advantage in the detection of cancer, diagnosis, and therapy. And it can also have properties such as antifungal, antibacterial, anti-inflammatory, antiviral and anti-angiogenic. Conclusion: In this review, recent upcoming advancement of biomedical application of nanotechnology and their future challenges has been discussed.

Mechanism and Kinetics of the Hydrogen Failure of Thermoelectric Materials during Water Electrolysis

2020 ◽  
Vol 2020 (10) ◽  
pp. 1102-1115
Author(s):  
M. A. Korzhuev ◽  
I. V. Katin ◽  
M. A. Kretova ◽  
E. S. Avilov
Keyword(s):  
Thermoelectric Materials ◽  
Water Electrolysis ◽  
Mechanism And Kinetics ◽  
Kinetics Of

Spectrocoulometry – a new spectro-electrochemical technique

1987 ◽  
Vol 52 (6) ◽  
pp. 1386-1396 ◽  
Author(s):  
Ján Mocák ◽  
Michal Németh ◽  
Mieczyslaw Lapkowski ◽  
Jerzy W. Strojek
Keyword(s):  
Optical Probe ◽  
Optical Signal ◽  
Open Circuit ◽  
Electrochemical Technique ◽  
Kinetics Of Oxidation ◽  
Hydrolytic Reaction ◽  
Experimental Errors ◽  
Mechanism And Kinetics ◽  
Kinetics Of

A spectrocoulometric macrocell with a direct-view optical probe was designed and constructed, where the optical signal is transferred by light-conducting glass or quartz fibres permitting to work at wavelengths above 410 or 300 nm. The method of measurement on the proposed equipment is described; it was tested in the study of the mechanism and kinetics of oxidation of Fe(bipy)32+ ions (bipy = 2,2'-bipyridyl) with the use of potentiostatic coulometric electrolysis with open-circuit relaxation at a suitable time. The primary product of electrolysis, Fe(bipy)33+, undergoes a follow-up hydrolytic reaction with the formation of a binuclear complex. The rate constant of the reaction of the first order involves the contributions, kBi, from all bases present in solution; the corresponding values for H2O, OH-, bipy, and CH3COO- ions at a ionic strength 0·5 mol dm-3 and 25 °C were determined as kOH = (5·0 ± 0·6) . 105 mol-1 dm3 s-1, kbipy = (1·3 ± 0·2) . 10-1 mol-1 dm3 s-1, kAc = (5·8 ± 1·0) . 10-2 mol-1 dm3 s-1, and kH2O is not significant with respect to experimental errors.

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