scholarly journals Influence of the parameters of hydrogen nitrogen nitrogen in a glow discharge on tribological and physico-chemical properties of steel 40X

2021 ◽  
Vol 101 (3) ◽  
pp. 31-41
Author(s):  
N. Stechishina ◽  
◽  
M. Stechishin ◽  
A. Martynyuk ◽  
N. Lukianyuk ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Physicochemical Properties ◽  
Current Density ◽  
Energy Levels ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Nitrogen Diffusion ◽  
Operating Characteristics ◽  
Energy Characteristics ◽  
Low Energies

One of the modern and effective methods of hardening metals is nitriding in a glow discharge in ammonia or in an anhydrous medium (nitrogen + argon) - BATR. This paper presents the results of experimental studies comparing the results of tribological and physicochemical properties of hardened surfaces obtained by nitriding with autonomous and interconnected BATR modes. The complex of traditionally fixed values of operating parameters (temperature, composition of the gas mixture, pressure and saturation time) without taking into account energy characteristics (voltage, current density and specific discharge power) significantly reduces the technological capabilities of BATR to achieve the necessary physicochemical properties of metal surfaces specified by conditions exploitation. Taking into account the energy characteristics of BATR, a significant reduction in the energy consumption of the nitriding process is achieved. The energy levels of the main subprocesses are significantly different: the formation of nitrides occurs at low energies, surface sputtering occurs at high voltage values, and nitrogen diffusion occurs at increased current density values. In cases where the energy of the flow is insufficient, either a glow discharge may not occur at all, or with a lack of voltage, the nitride ball on the surface is not sprayed and it acts as a barrier that prevents the diffusion process into the inner layers of the metal, which leads to low physicochemical and, correspondingly, tribological indicators of nitrided balls. The quantitative ratio between them and the required operational properties of the metal, respectively, can be achieved only through an independent combination of the energy and operating characteristics of BATR

Physico-chemical properties and wear resistance of nitrided steel 38KhMUA

2021 ◽  
Vol 103 (3) ◽  
pp. 63-69
Author(s):  
Mykola Skyba ◽  
Myroslav Stechyshyn ◽  
Mykola Lukianiuk ◽  
Volodymyr Kurskoi ◽  
Nataliia Mashovets ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Current Density ◽  
Energy Levels ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Discharge Power ◽  
Gas Mixture ◽  
Nitrogen Diffusion ◽  
Energy Characteristics ◽  
Specific Discharge

The influence of regime (temperature, composition of gas mixture and its pressure) and energy characteristics (voltage, current density, specific discharge power) at hydrogen-free-nitriding in a glow discharge (HFNGD) on the structure, phase composition of nitrided layers is investigated. It is shown that due to the combination of regime and energy parameters of HFNGD it is possible to achieve physical and chemical indicators of nitrided layers set by operating conditions. The set of traditionally fixed values of regime parameters (temperature, gas mixture connection, pressure and saturation time) without taking into account energy characteristics (voltage, current density and specific discharge power) significantly reduces the technological capabilities of HFNGD. With controlled regulation of the energy characteristics of HFNGD, a significant reduction in the energy consumption of the nitriding process is achieved. It is established that the energy levels of the main subprocesses differ significantly: the formation of nitrides occurs at low energies, surface sputtering is realized at high voltage values, and nitrogen diffusion occurs at high current densities. In cases where the flow energy is insufficient, either a glow discharge may not occur at all, or at insufficient stress the nitride layer on the surface is not sprayed and it acts as a barrier that prevents the diffusion process into the inner layers of the metal, leading to low physicochemical indicators of nitrided layers. The priority in the formation of one or another phase (, , u, ), the quantitative ratio between them and the required performance properties of the metal, respectively, can be achieved only through an independent combination of energy and regime characteristics of HFNGD.

Characteristics Of The Structure Formation Of Gypsum Binder Modified With Zinc Hydrosilicates

2020 ◽  
pp. 40-46
Keyword(s):  
Synergistic Effect ◽  
Physicochemical Properties ◽  
Structure Formation ◽  
Silicic Acid ◽  
Chemical Properties ◽  
Crystal Formation ◽  
Ability To Act ◽  
Chemical Factors ◽  
Sorption Characteristics

The authors' methodic for assessing the role of chemical and physic-chemical factors during the structure formation of gypsum stone is presented in the article. The methodic is also makes it possible to reveal the synergistic effect and to determine the ranges of variation of controls factors that ensure maximum values of such effect. The effect of a micro-sized modifier based on zinc hydro-silicates on the structure formation of building gypsum is analyzed and corresponding dependencies are found. It is shown that effects of influence of modifier on the properties of gypsum compositions are determined by chemical properties of modifier. Among the mentioned properties are sorption characteristics (which depend on the amount of silicic acid and its state) and physicochemical properties - the ability to act as a substrate during crystal formation. The proposed method can also be extended to other binding substances and materials. This article contributes to the understanding of the processes that occur during the structure formation of composites, which will make it possible to control the structure formation in the future, obtaining materials with a given set of properties.

scholarly journals Ethanol/Gasoline Blends as Alternative Fuel in Last Generation Spark-Ignition Engines: A Review on CO and HC Engine Out Emissions

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4034
Author(s):  
Paolo Iodice ◽  
Massimo Cardone
Keyword(s):  
Physicochemical Properties ◽  
Alternative Fuels ◽  
Experimental Studies ◽  
Alternative Fuel ◽  
Exhaust Emissions ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Spark Ignition Engines ◽  
The Impact

Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to investigate the effect on engine out emissions and combustion efficiency. In the next section, this article focuses on the impact of ethanol/gasoline fuels on CO and HC formation. Many studies related to combustion characteristics and exhaust emissions in spark-ignition engines fueled with ethanol/gasoline fuels are thus discussed in detail. Most of these experimental investigations conclude that the addition of ethanol with gasoline fuel mixtures can really decrease the CO and HC exhaust emissions of last generation spark-ignition engines in several operating conditions.

scholarly journals Physicochemical characterisation of kafirins extracted from sorghum grain and dried distillers grain with solubles related to their biomaterial functionality

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Umar Shah ◽  
Deepak Dwivedi ◽  
Mark Hackett ◽  
Hani Al-Salami ◽  
Ranjeet P. Utikar ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Physicochemical Properties ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Chemical Properties ◽  
X Ray ◽  
Distillers Grain ◽  
Sorghum Grain ◽  
Dried Distillers Grain ◽  
Polypeptide Profile

AbstractKafirin, the hydrophobic prolamin storage protein in sorghum grain is enriched when the grain is used for bioethanol production to give dried distillers grain with solubles (DGGS) as a by-product. There is great interest in DDGS kafirin as a new source for biomaterials. There is however a lack of fundamental understanding of how the physicochemical properties of DDGS kafirin having been exposed to the high temperature conditions during ethanol production, compare to kafirin made directly from the grain. An understanding of these properties is required to catalyse the utilisation of DDGS kafirin for biomaterial applications. The aim of this study was to extract kafirin directly from sorghum grain and from DDGS derived from the same grain and, then perform a comparative investigation of the physicochemical properties of these kafirins in terms of: polypeptide profile by sodium-dodecyl sulphate polyacrylamide gel electrophoresis; secondary structure by Fourier transform infra-red spectroscopy and x-ray diffraction, self-assembly behaviour by small-angle x-ray scattering, surface morphology by scanning electron microscopy and surface chemical properties by energy dispersive x-ray spectroscopy. DDGS kafirin was found to have very similar polypeptide profile as grain kafirin but contained altered secondary structure with increased levels of β-sheets. The structure morphology showed surface fractals and surface elemental composition suggesting enhanced reactivity with possibility to endow interfacial wettability. These properties of DDGS kafirin may provide it with unique functionality and thus open up opportunities for it to be used as a novel food grade biomaterial.

scholarly journals Determination of molar refractions and Abraham descriptors for tris(acetylacetonato)chromium(iii), tris(acetylacetonato)iron(iii) and tris(acetylacetonato)cobalt(iii)

2017 ◽  
Vol 41 (23) ◽  
pp. 14259-14265 ◽  
Author(s):  
Michael H. Abraham ◽  
William E. Acree ◽  
Anthony F. Fucaloro ◽  
Andrew W. Zanella
Keyword(s):  
Physicochemical Properties ◽  
Chemical Properties

Descriptors for tris(acetylacetonato) complexes of Cr(iii), Fe(iii) and Co(iii) can be used to assess chemical properties of the complexes and to predict numerous physicochemical properties.

scholarly journals Physico-Chemical Properties of Deep-Lying Oils

2021 ◽  
Vol 134 (3) ◽  
pp. 11-17
Author(s):  
I. G. Yashchenko ◽  
◽  
Y. M. Polishchuk ◽  
Keyword(s):  
Spatial Distribution ◽  
Physicochemical Properties ◽  
Chemical Properties ◽  
Oil Production ◽  
Urgent Problem ◽  
Physico Chemical ◽  
The World ◽  
Oil Gas

The article is devoted to the urgent problem of studying the features of the properties of poorly studied oils at great depths (more than 4,500 m), the need for development of which is caused by the continuing decline in oil production in traditional oil producing provinces. The analysis of the spatial distribution of reserves across the continents and countries of deep-seated oils and changes in their physico-chemical properties and the occurrence conditions, which made it possible to identify their main features. The studies used information on 21067 oil samples from 167 oil-bearing basins of the world, obtained from the database on the physicochemical properties of oils. The features of the physicochemical properties of deep-seated oils have been established, which are manifested in a decrease in the density and viscosity of oils, in a decrease in the content of sulfur and asphalt-resinous substances, and in an increase in the content of light fractions and oil gas in comparison with oils of small and medium depths.

scholarly journals Physico-technical approach to design of composites from mineral and polymer technogenic resources

2015 ◽  
Vol 1 ◽  
pp. 162 ◽  
Author(s):  
Gotfrīds Noviks
Keyword(s):  
Composite Materials ◽  
Experimental Studies ◽  
Process Efficiency ◽  
Operating Characteristics ◽  
Forming Process ◽  
Polymer Waste ◽  
Composite Forming ◽  
Different Types ◽  
Low Levels

<p class="R-AbstractKeywords"><span lang="EN-US">Artificial composite materials are currently being produced in large quantities, they are diverse and they are widely used in the economy. There have been extensive theoretical and experimental studies of different types of components, developed the calculation methods of composites production with predefined properties.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">At the same time industry produces a lot of mineral and polymer waste, which are practically technogenic resources, but their use is currently at quite low levels. The paper examines the possibilities to use technogenic resources- mineral (such as ash and clay) and organic (polymers -PET containers) for producing qualitative composite materials. For this purpose theoretical analysis and calculations of the physical properties of components and process parameters that determine the operating characteristics of the composite material were carried out.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">Composite-forming process efficiency determinative parameters were analysed: adhesion, the specific surface energy, specific free surface, adsorption capacity and the degree of dispersion of the particles.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">The role of external factors in processing of composite were examined – temperature, concentration of components.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">The characteristics of prepared samples of composites showed the possibility to use these waste for the development of qualitative products for different purposes.</span></p>

scholarly journals Evaluation of Physicochemical Properties and Microbial Populations of Soil of Bagale Forest Reserve, Girei Local Government Area, Adamawa State, Nigeria

2020 ◽  
pp. 13-21
Author(s):  
G. O. Ateh ◽  
M. G. Saka ◽  
E. E. Dishan ◽  
B. B. Meer
Keyword(s):  
Local Government ◽  
Physicochemical Properties ◽  
Soil Depth ◽  
Chemical Properties ◽  
Soil Samples ◽  
Local Government Area ◽  
Microbial Populations ◽  
Available Phosphorus ◽  
High Porosity ◽  
Forest Reserve

This study evaluated the relationship between selected physicochemical properties and microbial populations of the soil of Bagale Forest Reserve, Girei Local Government Area of Adamawa State, Nigeria. Five plots of 20 x 20 m were laid. Soil samples were collected from five different positions at two soil depths of 0-15 cm and 15-30 cm. The soil samples were isolated in the laboratory for microbial populations and determination of physical and chemical properties. The results obtained revealed that fungal population (7.65 x 105 cfu/ml) was the highest at the soil depth of 0-15 cm, representing 39% of the total microbial populations in the sampled soil of the study area. The results further revealed that the population (6.84 x 105 cfu/ml) of the bacteria had a positive effect on soils of the study area in terms of nitrogen fixation by Rhizobacterial spp. Chemical properties of the soil samples revealed that the available phosphorus exhibited the highest percentage (61.7%) at 0-15 cm soil depth. Analyses of soil physical properties recorded the highest percentage (49.0%) of sand at 0-15 cm soil depth. A similar percentage (50.0%) of sand was exhibited at the depth of 15-30 cm. These percentages accounted for the high porosity (29.0%) of the soil observed at the two soil levels in the study area and could be improved through the application of lime fertilizers. Application of appropriate fertilizers like NPK to improve the soil condition of the study area is highly recommended.

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