scholarly journals Pneumatic transport of bulk materials in construction of composite floating docks

2021 ◽  
pp. 1-14
Author(s):  
A.S. Rashkovskyi ◽  
A.V. Shchedrolosiev ◽  
V.M. Neiman ◽  
O.Y. Kanash
Keyword(s):  
Wear Resistance ◽  
Transport System ◽  
Flow Rate ◽  
Pneumatic Transport ◽  
Pipe Diameter ◽  
Bulk Materials ◽  
Useful Life ◽  
Materials Used ◽  
Theoretical Results

Investigations of pneumatic transport of bulk materials used in shipbuilding have carried out. Their abrasiveness, wear of straight and curved sections of pipelines were investigated. Theoretically, the dependences of the amount of wear on various factors were defined: abrasiveness and concentration of transported particles, flow rate, pipe diameter and wear resistance of its material, structural and operational features of the transport system, etc. Formulas for determining the maximum useful life of straight and curved sections of pipelines are obtained. Theoretical results confirmed experimentally.

scholarly journals Overview of Biocompatible Materials and Their Use in Medicine

Folia Medica ◽  
2019 ◽  
Vol 61 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Denitsa D. Kiradzhiyska ◽  
Rositsa D. Mantcheva
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Surface Modification ◽  
Medical Devices ◽  
Biomedical Devices ◽  
Bulk Materials ◽  
Advantages And Disadvantages ◽  
Materials Used ◽  
Host Tissues ◽  
Microbiological Properties

Abstract This survey presents a thorough overview of the main types of biomaterials used for the manufacturing of implants. The use of different materials for the creation and refinement of medical devices aims at optimizing their properties and raising the level of safety for the patients. The purpose of the study is to classify the most common bulk materials used in medicine according to their nature, interaction with the host tissues and their function in the organisms. Some important advantages and disadvantages of the different classes of implant materials are considered. In the last few years there is a strong tendency toward the surface modification of biomedical devices. Various trends in processing of the materials are focused on increasing their corrosion resistance, wear resistance, biocompatibility and microbiological properties.

EVALUATION OF TRIBOTECHNICAL PROPERTIES OF THE COATING OBTAINED BY ELECTRIC SPARK HARDENING

2020 ◽  
Vol 4 (141) ◽  
pp. 157-163
Author(s):  
IL’YA ROMANOV ◽  
◽  
ROMAN ZADOROZHNIY
Keyword(s):  
Wear Resistance ◽  
Reference Sample ◽  
Optical Microscope ◽  
Research Purpose ◽  
Tribotechnical Properties ◽  
Uncoated Surface ◽  
Before And After ◽  
Materials Used ◽  
Friction Track

When applying coatings using various methods on the surfaces of moving parts that work in joints, it is important to make sure that the coatings are strong and wear-resistant in order to return them to their original resource. All existing hardening technologies and materials used to perform coatings have their own characteristics, therefore, the quality of the resulting coatings can be judged only after specific tests. (Research purpose) The research purpose is in evaluating the properties of the coating obtained by the method of electric spark hardening, and its ability to resist friction and mechanical wear. (Materials and methods) Authors conducted tests on the basis of the "Nano-Center" center for collective use. A coating was applied on the BIG-4M unit with a VK-8 hard alloy electrode, tribological properties were evaluated on a CSM Instruments TRB-S-DE-0000 tribometer, the width of the friction track was measured after the test using an inverted OLYMPUS gx51 optical microscope, and samples were weighed before and after the test on a VLR-200 analytical balance. Conducted research in accordance with GOST 23.224-86 and RD 50-662-88 guidelines. (Results and discussion) The article presents performed tests on the run-in and wear resistance of the coating. The samples were worked on with a step-by-step increase in the load. During the tests, the friction force was drawed on the diagram. Authors compared the results with the reference sample, an uncoated surface. (Conclusions) The resulting coating has better run-in and wear resistance compared to the standard, and the increase in wear resistance in dry friction conditions is very significant.

scholarly journals Impact of Orifice-to-Pipe Diameter Ratio on Leakage Flow: An Experimental Study

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2189
Author(s):  
Tingchao Yu ◽  
Xiangqiu Zhang ◽  
Iran E. Lima Neto ◽  
Tuqiao Zhang ◽  
Yu Shao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Pipe Wall ◽  
Pressure Head ◽  
Diameter Ratio ◽  
Pipe Diameter ◽  
Leakage Flow ◽  
Leakage Flow Rate ◽  
Different Shapes ◽  
Real Scale

The traditional orifice discharge formula used to estimate the flow rate through a leak opening at a pipe wall often produces inaccurate results. This paper reports an original experimental study in which the influence of orifice-to-pipe diameter ratio on leakage flow rate was investigated for several internal/external flow conditions and orifice holes with different shapes. The results revealed that orifice-to-pipe diameter ratio (or pipe wall curvature) indeed influenced the leakage flow, with the discharge coefficient ( C d ) presenting a wide variation (0.60–0.85). As the orifice-to-pipe diameter ratio decreased, the values of C d systematically decreased from about 12% to 3%. Overall, the values of C d also decreased with β (ratio of pressure head differential at the orifice to wall thickness), as observed in previous studies. On the other hand, orifice shape, main pipe flow velocity, and external medium (water or air) all had a secondary effect on C d . The results obtained in the present study not only demonstrated that orifice-to-pipe diameter ratio affects the outflow, but also that real scale pipes may exhibit a relevant deviation of C d from the classical range (0.61–0.67) reported in the literature.

Variable Powder Flow Rate Control in Laser Metal Deposition Processes

2008 ◽  
Author(s):  
Lie Tang ◽  
Jianzhong Ruan ◽  
Robert G. Landers ◽  
Frank Liou
Keyword(s):  
Transport System ◽  
Flow Rate ◽  
Rate Control ◽  
Metal Deposition ◽  
Powder Flow ◽  
Laser Metal Deposition ◽  
Motion System ◽  
Powder Flow Rate ◽  
Deposition Processes ◽  
Flow Rate Control

This paper proposes a novel method, called Variable Powder Flow Rate Control (VPFRC), for the regulation of powder flow rate in laser metal deposition processes. The idea of VPFRC is to adjust the powder flow rate to maintain a uniform powder deposition per unit length even when disturbances occur (e.g., the motion system accelerates and decelerates). Dynamic models of the powder delivery system motor and the powder transport system (i.e., five–meter pipe, powder dispenser, and cladding head) are constructed. A general tracking controller is then designed to track variable powder flow rate references. Since the powder flow rate at the nozzle exit cannot be directly measured, it is estimated using the powder transport system model. The input to this model is the DC motor rotation speed, which is estimated on–line using a Kalman filter. Experiments are conducted to examine the performance of the proposed control methodology. The experimental results demonstrate that the VPFRC method is successful in maintaining a uniform track morphology, even when the motion system accelerates and decelerates.

ESTIMATION OF TRIBOLOGICAL PROPERTIES OF SELECTED PLASTICS MATERIALS MANUFACTURED BY EXTRUSION AND 3D PRINTING

Tribologia ◽  
2021 ◽  
Vol 294 (6) ◽  
pp. 7-12
Author(s):  
Henryk Bąkowski ◽  
Zbigniew Krzysiak
Keyword(s):  
Wear Resistance ◽  
3D Printing ◽  
Aluminium Alloy ◽  
Tribological Properties ◽  
Dry Friction ◽  
Tribological Characteristics ◽  
3D Printer ◽  
Reciprocating Motion ◽  
Block System ◽  
Materials Used

The following work presents the results of research about the assessment of tribological properties of plastics used as components in modes of transport. For this purpose, the wear resistance of materials used in 3D printing (PA6CF and ABS), and extrusion moulding (PA) were tested. The tribological research was carried out with the use of the T-05 tester in the roller-block system. The samples in the form of cuboids with a concave rounding of one wall were made on a 3D printer using the FDM method. The counter-sample was a ring made of aluminium alloy subjected to anodizing. The research was carried out under a variable loads, in reciprocating motion, under dry friction conditions. After that the tribological characteristics were assessed. The research and analysis of the results confirmed the possibility of using selected plastics in modes of transport.

An investigation on the possibility to improve the corrosion and cavitation resistance of SS304 steel by NiTi coatings

2021 ◽  
Vol 35 (04) ◽  
pp. 2150057
Author(s):  
Qunfeng Zeng ◽  
Khashayar Khanlari ◽  
Naiming Lin
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Niti Alloy ◽  
Preliminary Investigation ◽  
Industrial Applications ◽  
Cavitation Resistance ◽  
Niti Alloys ◽  
Materials Used ◽  
Ss 304 ◽  
Increasing Load

Equiatomic and near equiatomic NiTi alloys, showing good mechanical and thermal shape memory properties, are widely exploited in different industrial applications. In addition, NiTi alloys have promising anti-cavitation and corrosion-resistance properties. These advantages have provided opportunities to exploit NiTi alloys as the coatings for protecting materials used in the industrial applications. This study is a preliminary investigation aiming to evaluate the feasibility to form NiTi alloy coatings on SS304 steel by tungsten inert argon arc welding (TIG) technology. The microstructure analysis shows that the crystalline phases in NiTi coatings on SS 304 steel are TiNi-B2, TiNi-B19’ and Ni3Ti. The potential of the NiTi coatings to enhance the corrosion resistance and cavitation resistance behaviors of steel exposed to seawater is studied. NiTi coatings, with two different thicknesses of about 1.2 and 2 mm, having homogenous microstructures were successfully deposited on SS304 steel using TIG technology. Results of tests, done in aqueous solutions simulating seawater, showed that the formation of the oxide films on the surface of NiTi coatings increased the corrosion resistance and wear resistance and decreased the damage caused by the cavitation. Moreover, it was understood that the NiTi coatings with 2 mm in thickness show the superior performances than those with 1.2 mm in thickness. The tribological mechanisms responsible for the unique properties of NiTi alloy coatings were investigated. The wear-resistance behaviors of NiTi alloy coatings are greatly influenced by the friction conditions. Increasing load decreased CoF and the wear rate of the coatings were almost constant, which was attributed to the pseudoelasticity of NiTi alloy. The attractive properties of NiTi alloys that makes it most influential materials for industrial applications have also been discussed.

scholarly journals Research of the dependence of pneumatic conveyor compressors power on project parameters of transport machines

2018 ◽  
Vol 230 ◽  
pp. 01009 ◽  
Author(s):  
Sergij Raksha ◽  
Vladimir Bohomaz ◽  
Igor Shcheka ◽  
Volodymyr Stefanov ◽  
Alex Nesterenko
Keyword(s):  
Transport System ◽  
High Vacuum ◽  
Graphical Analysis ◽  
Pneumatic Transport ◽  
Analytical Dependence ◽  
Transport Systems ◽  
Concentration Coefficient ◽  
Drive Power ◽  
Design Data ◽  
Mixture Concentration

The paper considers the algorithm for calculating the pneumatic transport systems of the main constructions: with high vacuum and with different pressures. The analysis of the dependence of all calculation elements on the design data of the transport system of the considered structures was carried out. In order to accelerate the calculation of such systems, the analytical dependence of the power of the compressor drive on the type of cargo, the coefficient of concentration of the transported mixture, the design productivity, and the geometric parameters of the route, the number and types of auxiliary devices (ells and shutters) are constructed. A graphical analysis of the dependence of compressor drive power of the pneumatic transport systems with high vacuum and with different pressures on the design data: the mixture concentration coefficient, the length of transportation, the design productivity for the transportation of cement with a given route configuration. The directions for further research have been determined.

Wear resistance of materials used for slurry transport

Wear ◽  
2015 ◽  
Vol 332-333 ◽  
pp. 1104-1110 ◽  
Author(s):  
Yongsong Xie ◽  
Jiaren (Jimmy) Jiang ◽  
Kidus Yoseph Tufa ◽  
Sing Yick
Keyword(s):  
Wear Resistance ◽  
Materials Used ◽  
Slurry Transport

scholarly journals Static characteristics of hydrostatic thrust bearing considering the inertia effect on the region of supply hole

2018 ◽  
Vol 233 (1) ◽  
pp. 188-193
Author(s):  
Zhuxin Tian ◽  
Haiyin Cao ◽  
Yu Huang
Keyword(s):  
Flow Rate ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Experimental Results ◽  
Inertia Effect ◽  
Static Characteristics ◽  
Hole Radius ◽  
Inertia Parameter ◽  
Theoretical Results ◽  
Inertia Theory

In the previous studies on the hydrostatic thrust bearing, the differences between the theoretical results and experimental results are obvious when the inertia parameter S and the ratio of supply hole radius to bearing radius r0/ R become large enough. To explain the differences, in this study, the inertia effect on the region of supply hole is considered in discussing the static characteristics of hydrostatic thrust bearing, and then new expressions of pressure, load capacity, and flow rate are given. For the continuous parallel bearing, the results of this study agree well with experiments, thus there is no need for the extra modified inertia theory. For the step bearing with a large inertia parameter (e.g., S = 2), the results of this study agree with experiments on the recess region, and are closer to the experimental results than those of old method on the region of bearing land. So when the inertia parameter S and the ratio of supply hole radius to bearing radius r0/ R are large enough, the inertia effect on the region of supply hole cannot be ignored in discussing the static characteristics of hydrostatic thrust bearing.

scholarly journals Overlay materials used for increasing lifetime of machine parts working under conditions of intensive abrasion

2013 ◽  
Vol 59 (No. 1) ◽  
pp. 16-22 ◽  
Author(s):  
M. Müller ◽  
P. Hrabě
Keyword(s):  
Wear Resistance ◽  
Chemical Composition ◽  
Abrasive Wear ◽  
Laboratory Experiments ◽  
Optical Emission Spectroscopy ◽  
Optical Emission ◽  
Point Of View ◽  
Laboratory Results ◽  
Machine Parts ◽  
Materials Used

We evaluated a degree of the machine part abrasive wear with secondary focus on their hardness. The paper states laboratory results of overlay systems from their wear resistance point of view. Laboratory experiments were carried out by two-body abrasion on bonded abrasive of a P120 granularity. The results proved an increased abrasive wear resistance of martensitic, ledeburitic and stellitic overlays against eleven different original products. The overlay UTP Ledurit 60 reached the optimum values. The GD-OES (Glow Discharge Optical Emission Spectroscopy) method proved the different chemical composition of the overlay from the stated chemical composition of the overlaying electrode.    

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