scholarly journals The distribution regularities of structural, physical and mechanical characteristics of the fillings of shredded wood in the bunkers at the gravity movement

2016 ◽  
Vol 6 (3) ◽  
pp. 100-108
Author(s):  
Лозовецкий ◽  
Vyacheslav Lozovetskiy ◽  
Шадрин ◽  
Anatoliy Shadrin ◽  
Лебедев ◽  
...  

Described the experimental setup and presents the results of theoretical and experimental analytical studies of structural characteristics (coefficient of fully wood - porosity or the porosity) and physico-mechanical properties (coefficients of internal and external friction) of the materials crushed wood, a generalization which allowed us to obtain the calculated dependences for determination of their size by volume of bunkers axisymmetric geometry.

2018 ◽  
Vol 34 (2) ◽  
pp. 745
Author(s):  
Τ. Α. ΧΡΙΣΤΟΔΟΥΛΟΠΟΥΛΟΥ ◽  
Π. ΤΣΩΛΗ - ΚΑΤΑΓΑ ◽  
Γ. Χ. ΚΟΥΚΗΣ ◽  
Ν. ΚΟΝΤΟΠΟΥΛΟΣ

This paper deals with the systematic study of the microstructural characteristics of clay sediments. These characteristics which are closely connected to the physical and mechanical character of the sediments, are concerned with: a)the structural constituents, b)the microporosity and c)the structural bonds of the sediments. For the determination of the structural characteristics of clay sediments the Scanning Electron Microscope (SEM) and the Optical Microscope are widely used with a supplementary mineralogical analysis of sediment components and the determination of several physical and mechanical characteristics. The observations under the microscope must be focused on the distribution of mineralogical facies and micropores, on the size and shape of clay (micro-)aggregates, as well as on the kind of authigenic facies (e.g. micrite, sparry calcite) which play the role of cementing material. The proposed methodology was applied to the study of the microstructures of marly sediments from Northern Péloponnèse and the following types of microstructures were determined: a)matrix-skeletal, mixed type, coarse dispersed of low orientation, b)matrix, coagulative, medium dispersed of medium orientation and c)crystallized-cementated, fine or medium dispersed of low orientation.


2021 ◽  
Vol 273 ◽  
pp. 01032
Author(s):  
Igor Khozyaev ◽  
Dmitriy Savenkov ◽  
Oleg Kirischiev ◽  
Ylia Kirischieva ◽  
Tatiana Tupolskikh

The article is devoted to the study of the coefficients of external friction of grain agricultural products-friction in static and dynamic modes, as the most important physical and mechanical characteristics of bulk materials. The description of carousel laboratory unit, program, methodology and results of studies on the practical determination of the coefficients of external friction for typical agricultural grain products according to the materials typical of the working bodies of the production machines. As a result of the research, it was found that in the range of linear velocities from 0 to 1.75 m/s, there is a change in the friction coefficients, which has a nonlinear character.


2021 ◽  
Vol 0 (4) ◽  
pp. 12-19
Author(s):  
E.А. Guseinova ◽  
◽  
V.A. Mammadova ◽  
X.Ch. Abıyev ◽  
◽  
...  

The article provides information on the physical and mechanical properties of polymer-bitumen compositions obtained by modifying road bitumen BND 50/70 with elastomers SKEPT-60 and SKN-26 and determination of the obtained polymer-bitumen composites. The properties of composite samples of various concentrations (2.5, 3.0, 5.0%, 6.5 and 7.0%) were determined: needle depth, softening, brittleness and flash point, stretching and adhesion. It was determined that the physical and mechanical characteristics of polymer-bitumen composite materials obtained at high concentrations (6.5, 7.0%) are improved


2021 ◽  
Vol 899 ◽  
pp. 557-562
Author(s):  
Timur A. Borukaev ◽  
Luiza I. Kitieva ◽  
Abubekir Kh. Shaov ◽  
A.A. Kyarov

Based on magnesium carbonate and antimony oxide (V), MgO•Sb2O5 was obtained. In the formulation of fire-resistant cable PVC-plasticate, antimony (III) oxide was replaced by MgO•Sb2O5 and the fire resistance and physical and mechanical properties of the resulting compound were investigated. It is shown that the replacement of antimony (III) oxide in the composition of PVC cable compound MgO•Sb2O5 leads to the production of a compound that is not inferior in its characteristics to the original plastic compound. In particular, the fire resistance of cable PVC-plasticate, standard industrial formulation and with the obtained MgO•Sb2O5, is practically the same (OI=32%). It has been established that the physical and mechanical characteristics of the cable compound, when replacing antimony oxide (III) with MgO•Sb2O5 in the formulation, remain at the level of the original compound, while MgO×Sb2O5 will have a less negative impact on the environment.


2021 ◽  
Vol 42 ◽  
pp. 57-62
Author(s):  
Maria Stoicănescu

The 1.4301 stainless steel is part of the category of austenitic stainless steels, steels which do no undergo heat treatments in general, as they are intended for hot plastic deformation in particular. The aim of the research presented in this paper was to obtain significantly improved characteristics of the resistance properties in relation to the values obtained under classical conditions, by applying heat treatments. Samples taken from the delivery state material underwent annealing, quenching and ageing heat treatments. Subsequently, the samples thus treated were subjected to tests enabling the determination of the correlations between the heat treatment parameters, the structure and the properties.


2017 ◽  
Vol 750 ◽  
pp. 3-8
Author(s):  
Dragoş Cristian Achiţei ◽  
Petrică Vizureanu ◽  
Mirabela Georgiana Minciună ◽  
Nicanor Cimpoeşu ◽  
Bogdan Istrate

The paper presents aspects of structure modifications and properties for a CuZn alloy, after the appliance of heat treatments, at their specific parameters. The samples subjected to analysis, coming from cast bar, from which have been taken standard samples, with specific dimensions for experiments.Nonferrous alloys are subject frequently to annealing, quenching and tempering. The annealing follows the homogenization of structure after casting. The quenching followed by tempering is a spectacular modality to modify the mechanical properties for numerous nonferrous alloys.The characteristics of alloys have highlighted by experiments, using standard samples specific to the requests. The determination of alloying elements was made on optical spectrometer. The researches by SEM and optical microscopy, confirm the improvement of properties by obtaining uniform structures according to the applied thermal processing.


2019 ◽  
Vol 135 ◽  
pp. 01102
Author(s):  
Dmitriy Savenkov ◽  
Oleg Kirischiev ◽  
Ylia Kirischieva ◽  
Tatiana Tupolskikh ◽  
Tatiana Maltseva ◽  
...  

The article highlights the issues related to the study of physical and mechanical characteristics of bulk materials, namely internal friction coefficients in static and dynamic modes. An innovative device of the carousel type for determining the frictional characteristics of bulk materials is described, which allows to implement the tasks of practical determination of dynamic coefficients of internal friction. Presented the program, methodology and results of research on the practical study of the internal friction coefficient of typical bulk products of agricultural production in the range of linear velocities of displacement of layers from 0 to 2.79 m/s, the reliability of which is not lower than 0.878.


Clay Minerals ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 213-223 ◽  
Author(s):  
V. Lilkov ◽  
I. Rostovsky ◽  
O. Petrov

AbstractCement mortars and concretes incorporating clinoptilolite, silica fume and fly ash were investigated for changes in their physical and mechanical properties. It was found that additions of 10% clinoptilolite and 10% Pozzolite (1:1 mixture of silica fume and fly ash) were optimal for improvement of the quality of the hardened products, giving 8% and 13% increases in flexural and compressive strength respectively. The specific pore volume of the mortars incorporating zeolite decreased between the 28th and 180th day to levels below the values for the control composition due to the fact that clinoptilolite exhibits its pozzolanic activity later in the hydration. In these later stages, pores with radii below 500 nm increased at the expense of larger pores. The change in the pore-size distribution between the first and sixth months of hydration occurs mostly in the mortars with added zeolite.


2013 ◽  
Vol 430 ◽  
pp. 222-229 ◽  
Author(s):  
Oana Suciu ◽  
Teodora Ioanovici ◽  
Liviu Bereteu

Hydroxyapatite is a biomaterial, more exactly a bioceramic, from a category of materials frequently used in bone implants. In order to improve mechanical properties, hydroxyapatite is doped with different chemical substitutes, among which the most used are: Mg2*, Zn 2*, La3*, Y3*, In3* Bi3* CO32-, Si and Mn. In the paper are presented the modality of obtaining hydroxyapatite doped with magnesium through wet precipitation method and also the determination of its main mechanical characteristics. There is also an analysis on the effects of magnesium on the following mechanical properties: density, hardness, longitudinal modulus of elasticity, conductibility and thermal stability.


2020 ◽  
Vol 10 (11) ◽  
pp. 3707 ◽  
Author(s):  
Ali Ashrafian ◽  
Mohammad Javad Taheri Amiri ◽  
Parisa Masoumi ◽  
Mahsa Asadi-shiadeh ◽  
Mojtaba Yaghoubi-chenari ◽  
...  

In the field of pavement engineering, the determination of the mechanical characteristics is one of the essential processes for reliable material design and highway sustainability. Early determination of the mechanical characteristics of pavement is essential for road and highway construction and maintenance. Tensile strength (TS), compressive strength (CS), and flexural strength (FS) of roller-compacted concrete pavement (RCCP) are crucial characteristics. In this research, the classification-based regression models random forest (RF), M5rule model tree (M5rule), M5prime model tree (M5p), and chi-square automatic interaction detection (CHAID) are used for simulation of the mechanical characteristics of RCCP. A comprehensive and reliable dataset comprising 621, 326, and 290 data records for CS, TS, and FS experimental cases was extracted from several open sources in the literature. The mechanical properties are determined based on influential input combinations that are processed using principle component analysis (PCA). The PCA method specifies that volumetric/weighted content forms of experimental variables (e.g., coarse aggregate, fine aggregate, supplementary cementitious materials, water, and binder) and specimens’ age are the most effective inputs to generate better performance. Several statistical metrics were used to evaluate the proposed classification-based regression models. The RF model revealed an optimistic classification capacity of the CS, TS, and FS prediction of the RCCP in comparison with the CHAID, M5rule, and M5p models. Monte-Carlo simulation was used to verify the results in terms of the uncertainty and sensitivity of variables. Overall, the proposed methodology formed a reliable soft computing model that can be implemented for material engineering, construction, and design.


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