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1
Li, W. D., Ming Lv, and Sheng Qiang Yang. "Preliminary Research on the Post Treatment of Fluid Magnetic Abrasivetool." Key Engineering Materials 455 (December 2010): 161–64. http://dx.doi.org/10.4028/www.scientific.net/kem.455.161.
Повний текст джерелаАнотація:
Fluid magnetic abrasivetool(FMA) is one kind of latest finishing abrasivetool which is a sort of suspended fluid composed by magnetic particles, nonmagnetic abrasive particles, surfactants in a non-magnetizable carrier liquid. After a period of working time, the performance-life of the abrasivetool ended because of the cutting- blade of the abrasives particles being passive. While the most costly component- the magnetic particles (carbonyl iron particles) can be reused. This paper has made up two recovery flows to separated carbonyl iron particles from others.
2
Singh, Palwinder, Lakhvir Singh, and Sehijpal Singh. "Finishing of Tubes using Bonded Magnetic Abrasive Powder in an Abrasive Medium." Powder Metallurgy Progress 20, no. 1 (June 1, 2020): 1–11. http://dx.doi.org/10.2478/pmp-2020-0001.
Повний текст джерелаАнотація:
Abstract Magnetic abrasive flow finishing (MAFF) is an unconventional process capable of producing fine finishing with machining forces controlled by a magnetic field. This process can be utilized for hard to achieve inner surfaces through the activity of extrusion pressure, combined with abrasion activity of a magnetic abrasive powder (MAP) in a polymeric medium. MAP is the key component in securing systematic removal of material and a decent surface finish in MAFF. The research background disclosed various methods such as sintering, adhesive based, mechanical alloying, plasma based, chemical, etc. for the production of bonded MAP. This investigation proposes bonded MAP produced by mechanical alloying followed by heat treatment. The experiments have been conducted on aluminum tubes to investigate the influence of different parameters like magnetic field density, extrusion pressure and number of working cycles. The bonded magnetic abrasive powder used in MAFF is very effective to finish tubes’ inner surfaces and finishing is significantly improved after processing.
3
Mosina, T. V., V. V. Nepomnyashchii, K. A. Gogaev, S. M. Voloshchenko, and M. G. Askerov. "Composite ceramic powders for metal surface magnetic abrasive treatment." Refractories and Industrial Ceramics 52, no. 1 (May 2011): 41–43. http://dx.doi.org/10.1007/s11148-011-9361-6.
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4
Ikonnikov, Alexey, and Sergey Leonov. "Theoretical-Probability Model of Metal Removal During Magnetic-Abrasive Treatment." MATEC Web of Conferences 297 (2019): 09007. http://dx.doi.org/10.1051/matecconf/201929709007.
Повний текст джерелаАнотація:
The work is devoted to the issue of calculating material removal during magnetic abrasive processing. Cutting grains have random dimensional characteristics, are randomly located on the surface of the tool, the workpiece has an irregular profile. The cutting parts of the grain tops partially remove the chips, and partially elastically-plastic deform the metal. Part of the vertices falls into the risks on the surface of the workpiece formed by the previous machining, and part -into the risks from passing through the previous vertices. This process is determined by the probability of the contact of the top of the grain with the metal. The developed stochastic models make it possible to predict the removal of metal from the treated surface depending on the time and parameters of the operation, which creates the prerequisites for their use in the design of polishing operations.
5
Chen, Y., and Dong Ying Ju. "Application of Rare Earth Permanent Magnet on Magnetic Abrasive Machining." Key Engineering Materials 336-338 (April 2007): 712–14. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.712.
Повний текст джерелаАнотація:
Because of the raw material elements and its purity and so on, the Nd-Fe-B permanent magnet, the strongest magnetic material, which needs artificial synthesis, can hardly be used directly. The performance of the permanent magnet has not yet been greatly developed owing to the limitation of the artificial synthesizing technology, of the powder sintering technology and that of the application. In this paper, the magnetic abrasive machining method as a new application is put forward, and from this viewpoint, are discussed the performance and the processing technology of the permanent magnet and the magnetic abrasive machining method. A sintering route combining the direction heat treatment technique to increase the magnetic energy is suggested.
6
Tang, Liang, Xianguo Yan, Yijiang Jiang, Fan Li, and Haidong Zhang. "Effect of Magnetic Field Coupled Deep Cryogenic Treatment on Wear Resistance of AISI 4140 Steel." Advances in Materials Science and Engineering 2020 (March 30, 2020): 1–8. http://dx.doi.org/10.1155/2020/2589283.
Повний текст джерелаАнотація:
In this study, a new magnetic field coupled deep cryogenic treatment (MDCT) is developed and its effect on wear resistance of AISI 4140 steel is investigated. Compared with wear resistance of untreatment (UT), wear resistance of MDCT increases by 29%. Wear resistance is inversely proportional to the friction coefficient. The treatment promotes the phase transformation and dislocation movement to generate more martensite in multidirectional distribution and optimized carbide. It enhances material property and repairs surface defect. Moreover, the wear mechanism of MDCT is only abrasive wear in the form of microscopic cutting, while other process groups are oxidative wear and abrasive wear in the form of microscopic cutting and microscopic fracture.
7
Akulovich, L. M., L. E. Sergeev, and M. M. Dechko. "Influence of properties of the working technological environment on the surface roughness and productivity during magnetic abrasive machining." Proceedings of the National Academy of Sciences of Belarus, Physical-Technical Series 67, no. 1 (April 6, 2022): 39–48. http://dx.doi.org/10.29235/1561-8358-2022-67-1-39-48.
Повний текст джерелаАнотація:
The results of experimental studies of the surface roughness parameters of ball bearing treadmills made of steel SHX-15 and the performance of the magnetic abrasive treatment process depending on the properties of the components of the working process medium are presented. The research used methods of mathematical modeling of the technological process of magnetic abrasive processing, subsequent analysis of the obtained multivariate regression equations to identify the most significant technological factors according to the criteria of their interaction and relative influence on surface roughness and processing performance. The relative total contribution to the change in the roughness of the treated surface (Ra, microns) and processing performance (ΔG, mg/min) was established: single control technological factors affect 29,1 % and 48,2 %, respectively; interacting control technological factors 46.8 % and 45.9 %, respectively. The controlling technological factors in descending order of the degree of influence by generalized significance are arranged in the sequence: hydrogen pH, gradient of magnetic induction B (T/mm), microhardness of abrasive HV (GPa), coolant viscosity γ (cSt), processing time t (s) and magnetic permeability µ (mH/m). The interpretation of the physical mechanisms of interaction of controlling technological factors is given. The obtained results of a quantitative assessment of the relative total contribution of single control technological factors can be used in assigning modes of magnetic abrasive treatment of bearing rings, and their interaction – in studies of the synergism of the parameters of the working technological environment, which allows obtaining a much greater effect than using each parameter separately.
8
Avdeyev, Boris, Aleksey Vyngra, and Aleksander Bordiug. "Testing the efficiency of abrasive treatment of reconditioned parts using coolant cleaning in a magnetic sump." MATEC Web of Conferences 298 (2019): 00115. http://dx.doi.org/10.1051/matecconf/201929800115.
Повний текст джерелаАнотація:
This article discusses pilot study of effectiveness of abrasive machining of the recoverable parts for cleaning cooling lubricants involved in technological processes of processing of the parts. One of the cleaning methods is a magnetic sump, which has high efficiency at relatively low cost of operation and maintenance. Laboratory tests of the magnetic sump were carried out according to a full-factor experiment, varying with certain parameters in order to identify the purity index of cooling lubricant when cleaning from mechanical impurities. Dependencies are obtained that connect the value of purity index of coolant with the technological and structural parameters of the magnetic sump. The influence of the cooling lubricant purity index in the magnetic sump on the roughness of grinded surface of the samples was revealed. The most rational parameters of the magnetic sump have been determined at which optimum surface roughness is observed when processing the engine crankshaft using cooling lubricant cleaned in the magnetic sump.
9
Havrushkevych, Andrii, Volodymyr Geichuk, Nataliia Havrushkevych, Olexander Kravets, and Alla Romashko. "METHOD OF DESIGNING ROTOR HEADS FOR FINISHING CYLINDRICAL PARTS WITH UNIFORMLY LOCATED ELEMENTS ON THE PERIPHERAL." Transactions of Kremenchuk Mykhailo Ostrohradskyi National University, no. 4(129) (August 23, 2021): 124–34. http://dx.doi.org/10.30929/1995-0519.2021.4.124-134.
Повний текст джерелаАнотація:
Purpose. The purpose of these studies is to develop a method designing rotor heads for finishing cylindrical parts with evenly spaced elements on the periphery and approbation a technique at development a design a rotor head for realization magnetic-abrasive processing cylindrical gear wheels over a ring bath. Methodology.The design technique is based on the synthesis of structural-kinematic schemes and structural formulas of rotary machine composing.In the synthesis process are analyzed the possible general coordinate transformations matrices of the forming system of the rotor heads.The general matrix coordinate transformations is selected by the results of a comprehensive assessment the criteria of the intensity of magnetic abrasive treatment and the shape of the edge. Findings.The design technique is rep- resented by an algorithm that includes the stages of synthesis structural-kinematic schemes and structural formulas of the composing rotary machines and the stage for determining their basic design parameters and dimensions. Originality.The algorithm of development structural-kinematic schemes and structural formulas arrangement rotary machines for magnetic-abrasive processing blanks in the stage of definition and choice of rational modes is im- proved.This allows you to get theparticular level of quality of processing that is best for the whole set of machined sur- faces and edges of the work pieces. Practicalvalue.The design technique has been tested in the design and construction of the rotor head for magnetic-abrasive processing gears over the ring bath. The design of the magnetic system with a double-circuit magnetic circuit is developed, which allows to increase the width of the working zone up to 150 mm, and the outer diameter of the processed gears up to 400 mm. Conclusions. As a result of the carried out researches the tech- nique and recommendations on designing of rotor heads for finishing of cylindrical details with equally located ele- ments on periphery(gears, end and axial cutting tools, etc.) are developed.To increase the efficiency of the technique, it is necessary to conduct additional studies of tribotechnical properties of magnetic-abrasive tools with a wider coverage of fractions of particles and processed materials and especially experimental studies of resistance forces during the movement of bodies in the working environment.
10
Ustinovich, D. F., V. R. Sobol', and O. N. Mazurenko. "Low-Frequency Eddy Currents and Dissipative Processes under the Conditions of Magnetic Abrasive Treatment." Journal of Engineering Physics and Thermophysics 77, no. 1 (January 2004): 199–203. http://dx.doi.org/10.1023/b:joep.0000020739.85336.de.
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11
Maiboroda, V. S., Yu S. Nalimov, A. N. Solovar, M. N. Bobina, and N. N. Teslyuk. "Effect of Complex Magnetic-Abrasive and Chemical/Thermal Treatment on VT9 Alloy Fatigue Resistance." Strength of Materials 48, no. 5 (September 2016): 704–12. http://dx.doi.org/10.1007/s11223-016-9814-8.
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12
Wieczorek, A. N. "Influence of Shot Peening on Abrasion Wear in Real Conditions of Ni-Cu-Ausferritic Ductile Iron." Archives of Metallurgy and Materials 61, no. 4 (December 1, 2016): 1985–90. http://dx.doi.org/10.1515/amm-2016-0320.
Повний текст джерелаАнотація:
Abstract The paper presents results of the wear tests of chain wheels made of austempered ductile iron with various content of residual austenite. The aim of this study was to demonstrate the impact of the dynamic surface treatment (shot peening) on wear properties of surface layers of the chain wheels tested that were subjected to the action of quartz abrasive. Apart from determining the value of the abrasive wear, examinations of the magnetic phase content in the microstructure were carried out and plots of hardness of the surface layer as a function of the distance from the surface and microstructure of the materials were prepared. Based on the results, the following was found: an increase in the abrasive wear and a reduction in the hardness of the surface layer of chain wheels subjected to shot peening, as well as reduction of susceptibility to negative action of the shot for cast irons with the structure of upper ausferrite.
13
Maksimov, Dmitriy, Radmila Shcheglova, and Dmitriy Klochkov. "Technological assurance of the quality of processing of products from aluminum alloys with a complex geometric shape using magnetic abrasive processing." E3S Web of Conferences 326 (2021): 00033. http://dx.doi.org/10.1051/e3sconf/202132600033.
Повний текст джерелаАнотація:
In the presented article, the issue of the implementation of magnetic abrasive processing is considered in order to ensure the quality of surfaces of complex shapes of parts made of corrosion-resistant aluminum alloys. The implementation was carried out through theoretical and experimental research. In a theoretical study, the features of processing corrosion-resistant aluminum alloys, existing and possible schemes for magnetic-abrasive processing of surfaces of complex geometric shapes, including a combination of various working movements of the workpiece and pole pieces, are considered. In an experimental study, the dependence of the quality of the processed surface (roughness) on the size of the working gap between the workpiece and the working pole was determined. The result of the research is the determination of the optimal treatment schemes for surfaces with a complex geometric shape, as well as the derived exponential dependence of the change in surface roughness on the size of the working gap.
14
Bobyn, A. B., N. N. Bobyna, and V. S. Maiboroda. "Influence of the parameters of magnetic abrasive treatment on the surface roughness of carbide tools." Metaloznavstvo ta obrobka metalìv 89, no. 1 (March 30, 2019): 34–38. http://dx.doi.org/10.15407/mom2019.01.034.
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15
Oliker, V. E., T. Ya Gridasova, V. L. Sirovatka, E. N. Eliseeva, I. I. Timofeeva, and E. F. Grechishkin. "Effect of magnetic abrasive treatment on high-temperature oxidation of NiAl and NiAl–Re coatings." Powder Metallurgy and Metal Ceramics 48, no. 7-8 (July 2009): 466–77. http://dx.doi.org/10.1007/s11106-009-9142-7.
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Wu, Yong Bo, Takashi Sato, Wei Min Lin, K. Yamamoto, and Kunio Shimada. "The Detailed Performance of MCF Polishing Liquid in Nano-Precision Surface Treatment of Acrylic Resin." Advanced Materials Research 76-78 (June 2009): 331–36. http://dx.doi.org/10.4028/www.scientific.net/amr.76-78.331.
Повний текст джерелаАнотація:
This paper deals with the experimental investigation on the detailed performance of MCF (magnetic compound fluid) polishing liquid (MPL) in nano-precision surface treatment of acrylic resin that is essentially required for producing the model in the process of developing an inaugural mechanical system. The MPL is produced in practice by mixing iron powder, abrasive particle and -cellulose fiber into a MF (magnetic fluid), and hence a kind of functional fluid reacting to magnetic fields. Following the previous works confirming the performance of MPL in the surface finishing of acrylic resin, in this work a series of experiments were conducted to reveal how the process parameters affect the machining characteristics in details in order to establish the new technique. The results showed that a mirror surface can be easily obtained once the process parameters have been set up optimally.
17
Kukovitsky, E. F., S. G. Lvov, V. A. Shustov, and N. M. Lyadov. "Surface Integrity and Carbon Chemical Vapor Deposition on Nickel Foil: Surface Abrasive Treatment." ECS Journal of Solid State Science and Technology 4, no. 9 (2015): M51—M59. http://dx.doi.org/10.1149/2.0211508jss.
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18
Ho, Chao-Ching, Yong-Zhi Deng, Bo-En Tsai, and Chia-Lung Kuo. "Study on magnetic-field-based abrasive grains patterning for electroplating diamond wire saws." Journal of Laser Applications 34, no. 2 (May 2022): 022006. http://dx.doi.org/10.2351/7.0000552.
Повний текст джерелаАнотація:
In this study, the magnetic field-based abrasive grain patterning for the production of electroplating diamond wire saws was studied. During the manufacturing process of the electroplating diamond wire saw, a permanent magnet was used to perform magnetization of the carbon steel wire. In addition, the following two methods were further used to perform partial degaussing on the carbon steel wire. The first method refers to the laser degaussing method, and the second method refers to the electromagnetic degaussing method, followed by performing electroplating on the carbon steel wire that has undergone the degaussing process. The impacts of these two methods on the magnetization characteristics of the carbon steel wire were studied, the magnetic induction strength of the zone of degaussing, range of the zone of degaussing, production speed, etc., in order to reach a conclusion on the methods for degaussing of a carbon steel wire. In this study, a nanosecond laser with a wavelength of 355 nm was used to perform a partial degaussing treatment on the surface of a magnetized carbon steel wire. When the laser fluence is 11.56 J/cm2, the controlled degaussing region of the abrasive grains could be minimized to 83.8 μm.
19
Li, Zulai, Haibin Wang, Yuelin Zhao, Lei Wu, Fei Zhang, and Quan Shan. "Effect of progressive solid-solution treatment on microstructures, mechanical properties and impact abrasive wear behavior of alloyed high manganese steel." Materials Research Express 9, no. 3 (March 1, 2022): 036512. http://dx.doi.org/10.1088/2053-1591/ac5cad.
Повний текст джерелаАнотація:
Abstract Alloyed high manganese steel is a general type of wear-resistant steel, and its precipitates and austenite matrix grain sizes play an important role in impact abrasive wear behavior. Solid-solution treatment is an effective method to balance the size of the austenite grains and precipitates. This work attempts to find a new progressive solid-solution treatment to make alloyed high manganese steel castings refine the microstructure and balance the wear resistance under impact abrasive wear conditions. Compared with traditional solid-solution treatment, the MC- and M23C6-type carbide precipitates resulting from progressive solid-solution treatment decrease, and the tensile strength and impact toughness of steel are significantly increased. After the solid-solution treatment at different heating rates, the grain refinement effect is remarkable after shortening the holding time at 1100 °C and increasing the heating rate to 150 °C h−1. The impact abrasive wear test results show that, compared with the traditional solid-solution treatment at 1100 °C for 4 h, the wear resistance of high manganese steel has a 23.1% improvement after progressive solution treatment at 1100 °C for 2 h, and the wear failure forms of all the experimental steels are microcutting, oxidation wear and plastic deformation.
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Oliker, V. E., T. Ya Gridasova, I. I. Timofeeva, E. F. Grechishkin, and A. G. Gavrilenko. "Effect of magnetic treatment on the microstructure and abrasive resistance of WC–Co detonation-sprayed coatings." Powder Metallurgy and Metal Ceramics 51, no. 5-6 (September 2012): 345–52. http://dx.doi.org/10.1007/s11106-012-9439-9.
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Gençer, Gökçe Mehmet, Fatih Kahraman, and Coşkun Yolcu. "Role of enhanced surface grain refinement and hardness improvement induced by the combined effect of friction stir processing and ultrasonic impact treatment on slurry abrasive wear performance of silicon carbide particle reinforced A356 composites." Materials Research Express 8, no. 12 (December 1, 2021): 126513. http://dx.doi.org/10.1088/2053-1591/ac3f5c.
Повний текст джерелаАнотація:
Abstract In this study, the slurry abrasive wear behavior of silicon carbide particle reinforced A356 composite alloy was investigated after the different surface mechanical attrition treatments. It is known that the aluminum matrix composites produced by the stir casting method have some deficiencies (e.g unfavorable microstructure formation, particle clustering, porosity formation, etc). These kinds of drawbacks of the composites adversely affect the surface mechanical properties of materials such as wear resistance. For this purpose, the surface properties of the silicon carbide reinforced A356 matrix composites fabricated through the stir casting method were improved by using friction stir processing (FSP) and ultrasonic impact treatment (UIT) in the study. The results indicated that a remarkable increase was observed in the hardness and wear resistance of the cast composite via FSP and ultrasonic impact treatment following friction stir processing (FSP + UIT). The hardness of the stir zone after FSP and FSP + UIT was determined as 82.7+−2 HV and 101.9 +−3 HV0.2, respectively. The stir zone showed a similar tendency also in slurry abrasive wear resistance. FSP increased the wear resistance in the stir zone at the rate of 33.9% while it was determined as 35.5% for FSP + UIT. The microstructural modification of the cast composite that occurred after FSP was clearly demonstrated via optical microscope and scanning electron microscopy (SEM) examinations. Enhanced grain refinement after FSP + UIT was indicated especially by x-ray diffraction analysis (XRD). According to the findings, it was observed that the application of ultrasonic impact treatment following the friction stir processing can be used to obtain an enhanced microstructure and extra hardness increment in the surface of the SiC reinforced A356 alloy, thus resulting in slurry abrasive wear resistance increment.
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Nalimov, Yu S., V. S. Maiboroda, D. Yu Dzhulii, and M. M. Teslyuk. "Effect of Complex Magnetic-Abrasive and Chemical-Thermal Treatment on the Fatigue Resistance of VT8 Alloy Compressor Blades." Strength of Materials 52, no. 6 (November 2020): 947–52. http://dx.doi.org/10.1007/s11223-021-00248-4.
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Ha, Kyeongsik, Young Keun Park, Taehwan Kim, Gyeong Yun Baek, Jong Bae Jeon, Do-sik Shim, Young Hoon Moon, and Wookjin Lee. "Effects of Heat Treatment Condition and Counter Materials on the Wear Behavior of Laser Direct Energy Deposited Fe-8Cr-3V-2Mo-2W Alloy." Korean Journal of Metals and Materials 58, no. 10 (October 5, 2020): 680–92. http://dx.doi.org/10.3365/kjmm.2020.58.10.680.
Повний текст джерелаАнотація:
This study aimed to investigate the wear performance of laser direct energy deposited Fe-8Cr3V-2Mo-2W alloy under various wear environments, in terms of different heat treatment conditions. Ball on disk tribology tests were performed using high-carbon steel and zirconia balls as counter materials. The wear rates of the alloy depended significantly on both the wear sliding speed and the wear load. Microstructural observations of the worn surface and the wear debris indicated intensive tribo-oxidative wear that was presumably responsible for the strong dependency of the wear rate on the wear sliding speed. Regardless of the type of counter materials, the alloy in the as-built state had better wear performance than the alloy with heat treatments. Therefore, the use of the alloy without post heat treatment would be favorable to obtain long-term durability of the alloy in severe wear environments. The wear tests with two different counter materials of high-carbon steel and zirconia showed the high-carbon steel counter material had a higher wear rate than the zirconia. This was thought to be due to that strong third-body abrasive actions of the high-carbon steel counter material, evidenced by the severe abrasive wear of the counter material.
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Zhao, Yunhao, Jason Ratay, Kun Li, Hitomi Yamaguchi, and Wei Xiong. "Effects of Magnetic Abrasive Finishing on Microstructure and Mechanical Properties of Inconel 718 Processed by Laser Powder Bed Fusion." Journal of Manufacturing and Materials Processing 6, no. 2 (April 8, 2022): 43. http://dx.doi.org/10.3390/jmmp6020043.
Повний текст джерелаАнотація:
Surface finishing is challenging in the context of additively manufactured components with complex geometries. Magnetic abrasive finishing (MAF) is a promising surface finishing technology that can refine the surface quality of components with complex shapes produced by additive manufacturing. However, there is insufficient study regarding the impact of MAF on microstructure–property relationships for additively manufactured builds, which is critical for evaluating mechanical performance. In this work, we studied the effects of different combinations of MAF and heat treatment steps on the microstructure–property relationships of Inconel 718 superalloys made by laser powder bed fusion (LPBF). The application of MAF was found to significantly reduce the surface roughness and refine the grain size of aged alloys. Moreover, MAF was able to increase the alloy elongation, which could be further influenced by the sequence of MAF and different heat treatment steps. The highest elongation could be achieved when MAF was performed between homogenization and aging processes. This work indicates that an effective combination of surface finishing and heat treatment is critical for the improvement of alloy performance. Furthermore, it demonstrates a promising solution for improving the performance of LPBF Inconel 718 by integrating MAF and heat treatment, which provides new perspectives on the post-processing optimization of additively manufactured alloys.
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Chmielus, Markus, and Peter Müllner. "Effects of Surface Pinning, Locking and Adaption of Twins on the Performance of Magnetic Shape-Memory Alloys." Materials Science Forum 684 (May 2011): 177–201. http://dx.doi.org/10.4028/www.scientific.net/msf.684.177.
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We study the effect of surface modifications and constraints on the mechanical properties of Ni-Mn- Ga single crystals, which are imposed by (i) structural modifications near the surface, (ii) mounting to a solid surface, and (iii) guiding the stroke. Spark eroded samples were electropolished and characterized before and after each polishing treatment. Surface damage was then produced with spark erosion and abrasive wearing. Surface damage stabilizes and pins a dense twin-microstructure and prevents twins from coarsening. The density of twins increases with increasing degree of surface deformation. Twinning stress and hardening rate during mechanical loading increase with increasing surface damage and twin density. In contrast, when a damaged surface layer is removed, twinning stresses, hardening rate, and twin density decrease. Constraining the sample by mounting and guiding reduces the magnetic-field-induced strain by locking twins at the constrained surfaces. . For single-domain crystals and for hard magnetic shape-memory alloys, external constraints strongly reduce the magnetic-field-induced strain and the fatigue lifetime is short. In contrast, for selfaccommodated martensite and for soft magnetic shape-memory alloys, the twin-microstructure adapts well to external constraints and the fatigue lifetime is long. The performance of devices with MSMA transducers requires managing stress distributions through design and control of surface properties, microstructure, and constraints.
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Senyut, V. T. "Sintering of composite materials for tool appointment, based on impact diamonds, under high pressure and temperatures." Proceedings of the National Academy of Sciences of Belarus, Physical-Technical Series 66, no. 1 (April 2, 2021): 47–57. http://dx.doi.org/10.29235/1561-8358-2021-66-1-47-57.
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The article presents the results of a study of composite materials based on diamond-lonsdaleite abrasive (DLA) and various binders (Fe–Ti mechanocomposite, silicon carbide SiC). A metal-matrix composite material with a multimodal nano- and microlevel structure, characterized by increased adhesion of diamond grains to the binder, is obtained on the basis of impact diamonds and a Fe–Ti nano-mechanical composite. It is shown that the use of impact diamonds in comparison with synthetic diamonds makes it possible to reduce the pressure of thermobaric treatment by 30–50 % at the same sintering temperatures. The use of Fe–Ti–DLA composites in the process of magnetic-abrasive polishing (MAP) makes it possible to increase the removal rate of material based on silicon by 1.5–2 times and reduce the processing time by 30 % compared to ferroabrasive powder (FAP) based on synthetic diamonds. The effect of adding of silicon carbide on the process of obtaining a superhard composite material impact diamond – SiC is investigated. It is found that adding of SiC helps to reduce the defectiveness of the material and increase the homogeneity of its structure in comparison with the material without adding of a binder. In this case, an increase in the content of SiC and Si also leads to an inversion of the structure type of the superhard composite from polycrystalline to matrix. It is found that the additional use of amorphous soot and boron affects the refinement of the matrix structure of the composite material due to the formation of boron carbide and secondary finely dispersed silicon carbide.
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Myszka, D., and A. Wieczorek. "Effect of Phenomena Accompanying Wear in Dry Corundum Abrasive on the Properties and Microstructure of Austempered Ductile Iron with Different Chemical Composition." Archives of Metallurgy and Materials 60, no. 1 (April 1, 2015): 483–90. http://dx.doi.org/10.1515/amm-2015-0078.
Повний текст джерелаАнотація:
Abstract The research described in this article is a fragment in the series of published works trying to determine the applicability of new materials for parts of the mining machinery. Tests were performed on two groups of austempered ductile iron - one of which contained 1.5% Ni and 0.5% Mo, while the other contained 1.9% Ni and 0.9% Cu. Each group has been heat treated according to the three different heat treatment variants and then the material was subjected to detailed testing of mechanical properties and abrasion wear resistance, measuring also hardness and magnetic properties, and conducting microstructural examinations. The results indicated that each of the tested materials was senstive to the surface hardening effect, which resulted in high wear resistance. It has been found that high temperature of austempering, i.e. 370°C, favours high wear resistance of ductile iron containing nickel and molybdenum. Low temperature of austempering, i.e. 270°C, develops high wear resistance in ductile iron containing nickel and copper. Both these materials offer completely different mechanical properties and as such can be used for different and specific applications.
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Hasan, Jafri. "Meniscus Root Repair." Orthopaedic Journal of Sports Medicine 7, no. 11_suppl6 (November 1, 2019): 2325967119S0046. http://dx.doi.org/10.1177/2325967119s00462.
Повний текст джерелаАнотація:
Meniscal root tears defined as bony or soft tissue root avulsion injuries or radial tears within 1cm of the meniscal root attachment. If it is not treated properly can cause early development of osteoarthritis. The meniscal root tears leading to compromised hoop stress and decreased tibiofemoral contact area and increased contact pressures in the involved compartment. To confirm the diagnosis is through arthroscopic as a diagnostic and treatment and through magnetic resonance imaging. Not all meniscal root tears can be treated surgically, especially if they have multiple comorbidities or advanced age, severe osteoarthritis, non-symptomatic chronic meniscal root tears and significant mal-alignment of the affected compartment then the treatment of choice is to give a symptomatic treatment like non-steroid anti-inflammatory drug, and activity modification. Meniscectomy has been found to induce a high rate of arthritis progression postoperatively. There are two most common meniscal root repair techniques which are trans-tibial pullout repair and suture anchor repair that now preferred over meniscectomy. The most important thing to consider when repairing the meniscal root is the right anatomically repair. It has been proven that non-anatomical meniscal root repair will not able to restore to the normal function because the conversion of femorotibial loads into circumferential tension may be altered, with functional impairment of the knee. Anchor suture technique shows a greater degree of healing and better biomechanical outcome. The suture anchor technique uses “all-inside" fixation and avoids the need for a distal fixation which potentially places abrasive forces on the sutures used. The trans-tibial pullout repair can restore the attachment and contact pressure near normal value, also the tunnel drilling stimulating growth factors and progenitor cells from bone marrow and facilitate the ability of meniscus to convert axial load into hoop stress. The concern of trans-tibial pullout repair is its ‘bungee effect’ and repetitive loading resulted in the displacement of this repair complex and might compromise healing because of decreased stiffness and micromotion of the meniscus-suture complex.
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Skotnicki, Wojciech, and Dariusz Jędrzejczyk. "The Comparative Analysis of the Coatings Deposited on the Automotive Parts by the Cataphoresis Method." Materials 14, no. 20 (October 17, 2021): 6155. http://dx.doi.org/10.3390/ma14206155.
Повний текст джерелаАнотація:
The paper presents preliminary research focused on the determination of the influence of surface preparation on the quality of the paint coating obtained by the cataphoresis method (KTL). The tests were carried out on steel parts used in the construction of trailers and truck bodies. The first research group consisted of cold-rolled and chemically cleaned parts, the second group were mechanically cleaned with abrasive blasting. In order to determine the influence of surface treatment on the corrosion resistance of the tested coatings, besides a corrosion test, roughness measurements were also carried out. Tests were performed on the crude surface and after coating deposition. Moreover, tests were supplemented by measuring the thickness of the coating using the magnetic induction method and the hardness with the use micro and nano hardness testers. Measurements of the tribological parameters under dry friction conditions were performed using a T11 tester. The corrosion resistance of the applied coatings was determined in a salt spray test. The obtained results were compared to those that were determined for different zinc coatings. It has been shown that the method of base steel surface preparation affects every measured parameter and property of tested paint coatings. The quality of the coating deposited on the steel base after chemical cleaning is much better than the one applied to the sandblasted surface. The measured corrosion resistance of the tested paint coatings is only greater than the corrosion resistance of the lamellar zinc coating. The other zinc coatings (galvanic, hot-dip, sherardized) show corrosion resistance by an order of magnitude higher.
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Vollprecht, Daniel, Katharina Plessl, Simone Neuhold, Fritz Kittinger, Wolfgang Öfner, Peter Müller, Robert Mischitz, and Klaus Philipp Sedlazeck. "Recovery of Molybdenum, Chromium, Tungsten, Copper, Silver, and Zinc from Industrial Waste Waters Using Zero-Valent Iron and Tailored Beneficiation Processes." Processes 8, no. 3 (February 28, 2020): 279. http://dx.doi.org/10.3390/pr8030279.
Повний текст джерелаАнотація:
Zero-valent iron (ZVI) has been used for water treatment for more than 160 years. However, passivation of its surface often constituted a problem which could only be tackled recently by the innovative Ferrodecont process using a fluidized bed reactor. In this study, pilot scale experiments for the removal of Mo, Cr, W, Cu, Ag and Zn from two industrial waste water samples and lab-scale experiments for the beneficiation of the abrasion products are presented to integrate the Ferrodecont process into a complete recycling process chain. Firstly, 38.5 % of Cu was removed from sample A, yielding abrasion products containing 33.1 wt% Cu as metallic copper (Cu) and various Cu compounds. The treatment of sample B removed 99.8 % of Mo, yielding abrasion products containing 17.8 wt% of Mo as amorphous phases or adsorbed species. Thermal treatment (1300 °C) of the abrasion product A indicated a reduction of delafossite to metallic Cu according to differential scanning calorimetry (DSC), thermogravimetry (TG) and X-ray diffraction (XRD), which was successfully separated from the magnetic iron phases. Hydrometallurgical treatment (1.5 M NaOH, 3 d, liquid:solid ratio (L:S) = 15:1) of sample B yielded aqueous extracts with Mo concentrations of 5820 to 6300 mgL−1. In conclusion, this corresponds to an up to 53-fold enrichment of Mo during the entire process chain.
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Taha, A. A., P. S. Fleming, R. G. Hill, and M. P. Patel. "Enamel Remineralization with Novel Bioactive Glass Air Abrasion." Journal of Dental Research 97, no. 13 (August 6, 2018): 1438–44. http://dx.doi.org/10.1177/0022034518792048.
Повний текст джерелаАнотація:
Enamel demineralization or white spot lesions (WSLs) are a frequent complication associated with fixed appliance–based orthodontic treatment. The remineralization potential of a novel fluoride-containing bioactive glass (QMAT3) propelled via an air abrasion system was compared with Sylc glass and artificial saliva on artificially induced WSLs. Thirty extracted human premolars were randomly assigned into 3 groups ( n = 10) per method of treatment and scanned with optical coherence tomography and noncontact profilometer in the 4 enamel states: sound, demineralized, after glass propulsion, and after immersion in artificial saliva. Knoop hardness testing was also performed. Twenty additional prepared teeth samples were also randomly selected for examination by scanning electron microscopy and energy-dispersive X-ray spectroscopy (2 teeth per technique) under each of the 4 enamel conditions. 19F MAS-NMR (magic angle spinning–nuclear magnetic resonance) was also used to detect the type of apatite formed on the enamel surface. Significant enamel remineralization with surface roughness and intensity of light backscattering similar to that of sound enamel was observed following treatment with QMAT3. In addition, mineral deposits were detected on the remineralized enamel surfaces, forming a protective layer and improving its hardness. This layer was rich in calcium, phosphate, and fluoride; 19F MAS-NMR confirmed the formation of fluorapatite. This finding is particularly beneficial since fluorapatite is more chemically stable than hydroxyapatite and has greater resistance to acid attack. Hence, a promising fluoride-containing bioactive glass for enamel remineralization has been developed, although further clinical evaluation and refinement is required.
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Tatarintseva, E. A., and L. N. Olshanskaya. "Obtaining effective oil sorbents based on chemical industry waste for water treatment." Industrial processes and technologies 1, no. 1 (2021): 6–16. http://dx.doi.org/10.37816/2713-0789-2021-1-1-6-16.
Повний текст джерелаАнотація:
It was proposed new technologies for producing effective oil sorbents based on chemical industry waste. It was shown the possibility of using PET waste as a binder in the produc- tion of oil sorbents with specific properties (hydrophobicity, oleophilicity, magnetic proper- ties) using thermally expanded and oxidized graphite (TEG and OG) and ferritized iron- containing galvanic sludge (FGS). The presence of iron ions in the galvanic sludge allows one to obtain magnetite and ferrites during ferritization, which leads to the appearance of magnetic properties in FGS, established using a vibration magnetometer, the saturation induction was ~ 0.02 T. Electroplating sludge was carried out at t ≈ 1000 oC and τ = 1.5 hr with preliminary mechanical activation. The physicomechanical, chemical, and sorption properties of the obtained oil sorbents (bulk density, abrasion, grindability, particle size distribution, oil capacity, moisture capacity, wettability, buoyancy, specific surface area, chemical composition, adsorption capacity of materials under static and dynamic conditions) are studied. It was found that sorption ma- terials have 100% buoyancy, are highly active in cleaning water surface from films of oil products with different thicknesses (1–5 mm). It was shown that sorption capacity increases with increasing film thickness and reaches a maximum value at a thickness of 3 mm. The cleaning efficiency is 99.0%. It has been established that the sorption capacity of the sorption material (SM) depends on the nature of oil products, its viscosity, solubility and initial concentration in water. It is proved that the processes of sorption of oil products proceed by the physical mechanism, which can be represented as the oleophilic interaction of particles of the Sorption material and oil products, which is confirmed by the type of sorption isotherms, which are type II and IV according to the BDT theory and type L according to the Hills classification char- acteristic of polymolecular adsorption. The obtained adsorption isotherms were processed in the framework of the Langmuir and Dubinin – Radushkevich models, and the constants of the adsorption equations were calculated.
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Yang, Shan-Wei, Yong-Ji Chen, Ching-Jung Chen, Jen-Tsai Liu, Chin-Yi Yang, Jen-Hao Tsai, Huai-En Lu, San-Yuan Chen, and Shwu-Jen Chang. "High-Density Horizontal Stacking of Chondrocytes via the Synergy of Biocompatible Magnetic Gelatin Nanocarriers and Internal Magnetic Navigation for Enhancing Cartilage Repair." Polymers 14, no. 4 (February 19, 2022): 809. http://dx.doi.org/10.3390/polym14040809.
Повний текст джерелаАнотація:
Osteoarthritis (OA) is a globally occurring articular cartilage degeneration disease that adversely affects both the physical and mental well-being of the patient, including limited mobility. One major pathological characteristic of OA is primarily related to articular cartilage defects resulting from abrasion and catabolic and proinflammatory mediators in OA joints. Although cell therapy has hitherto been regarded as a promising treatment for OA, the therapeutic effects did not meet expectations due to the outflow of implanted cells. Here, we aimed to explore the repair effect of magnetized chondrocytes using magnetic amphiphilic-gelatin nanocarrier (MAGNC) to enhance cellular anchored efficiency and cellular magnetic guidance (MG) toward the superficial zone of damaged cartilage. The results of in vitro experiments showed that magnetized chondrocytes could be rapidly guided along the magnetic force line to form cellular amassment. Furthermore, the Arg-Gly-Asp (RGD) motif of gelatin in MAGNC could integrate the interaction among cells to form cellular stacking. In addition, MAGNCs upregulated the gene expression of collagen II (Col II), aggrecan, and downregulated that of collagen I (Col I) to reduce cell dedifferentiation. In animal models, the magnetized chondrocytes can be guided into the superficial zone with the interaction between the internal magnetic field and MAGNC to form cellular stacking. In vivo results showed that the intensity of N-sulfated-glycosaminoglycans (sGAG) and Col II in the group of magnetized cells with magnetic guiding was higher than that in the other groups. Furthermore, smooth closure of OA cartilage defects was observed in the superficial zone after 8 weeks of implantation. The study revealed the significant potential of MAGNC in promoting the high-density stacking of chondrocytes into the cartilage surface and retaining the biological functions of implanted chondrocytes for OA cartilage repair.
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Skoblo, T., I. Rybalko, O. Nanka, and O. Saychuk. "Evaluation of the wear of the duckfoot sweep cultivator blades and the technology of their hardening." Problems of tribology 100, no. 2 (June 23, 2021): 6–18. http://dx.doi.org/10.31891/2079-1372-2021-100-2-6-18.
Повний текст джерелаАнотація:
In recent years, research and developments related to the creation of new areas using nanotechnology take a special place in scientific achievements. They are developed and widely used in Physics, Chemistry, Biology, Electronics, Medicine, Food Production and to a much lesser extent in Engineering. This is due to the fact that there are different requirements to parts and products used in mechanical engineering, they have a complex shape, are made of different materials, production methods, heat treatment. While operating, their working layer undergoes degradation with a significant change in structure and their hardening using nanocoatings may turn out to be ineffective in both technical and economic aspects. In this case, only a specific approach, which is determined by comprehensive research with identification of the main factors of parts damageability in specific production and operation conditions, can be expedient. In addition, in some cases for hardening, repair and restoration of parts it is expedient to use surfacing methods with the introduction of modifying agents in a liquid bath during crystallization. These modifying agents are nano-and dispersed diamonds, which make it possible to adjust temperature parameters of crystallization, grain size, and stress level. This approach allows using high-alloyed, high-carbon electrodes even for thin-walled steel and cast iron products. In this case, the diamond inclusions additive plays the role of micro-refrigerators, which significantly change the crystallization temperature range. It is important to determine the optimal dose of the introduction of such a modifier and ensure uniform distribution the components in the coating. The presented work is devoted to the new technology development of hardening of cultivator blades metal with nano-and dispersed diamond additives, which are the part of the detonation charge from the disposal of ammunition. Nowadays, in agriculture, a large number of tillage implements are used for tillage, the working bodies of which are sweep blades. They are operated under conditions of abrasive particles impact, and this is accompanied by their intense wear with a corresponding change in the geometric dimensions of the main working surfaces. The worn sweep blades significantly reduce efficiency and quality of the carried-out work. The analysis of the effective choice of surfacing materials for hardening and improving their performance has been carried out and the nature of wear has been evaluated in order to identify areas of maximum damage and to determine the optimal method. It is known that T-590 and T-620 electrodes are used for the restoration surfacing of tillage implements. It was found the hardfacing of thin-walled parts is accompanied by a smaller heat sink and, in some cases, they are flooded with defect formation. To reduce it, a non-magnetic fraction of detonation charge from ammunition disposalin the form of an electrode modification was introduced, which ensured the uniform distribution the components in the coating. The method of the X-ray electron-probe analysis has been used to evaluate features of structure formation and component distribution along the perimeter of the coating. It was found out that this method of hardening reduces heat input and increases the microhardness and wear resistance of the surfaced coating, reduces the transition zone and thermal impact. The recommended method of metal hardening of new cultivator blades is to apply stripes on the point tip and wings of blades. On the basis of the nature of wear, the expediency of applying stripes on the point tip of the cultivator blade from the front side, and on wings from the rear side, is justified. The optimal geometrical dimensions of hardening stripes and their location on the blade are presented, which allows minimizing the local stresses and increasing wear resistance.
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Pfandl, Kerstin, Bastian Küppers, Stefanie Scheiber, Gerhard Stockinger, Johannes Holzer, Roland Pomberger, Helmut Antrekowitsch, and Daniel Vollprecht. "X-ray fluorescence sorting of non-ferrous metal fractions from municipal solid waste incineration bottom ash processing depending on particle surface properties." Waste Management & Research 38, no. 2 (October 17, 2019): 111–21. http://dx.doi.org/10.1177/0734242x19879225.
Повний текст джерелаАнотація:
A heavy non-ferrous metal fraction (< 50 mm) of municipal solid waste incineration bottom ashes from wet-mechanical treatment was separated by screening, magnetic separation and eddy-current separation into ferrous metals, non-ferrous metals and residual sub-fractions. The non-ferrous metal fractions were divided and subjected to (i) a washing process, (ii) dry abrasion and (iii) no mechanical pre-treatment to study the effect of resulting different surface properties on a subsequent X-ray fluorescence sorting into precious metals, zinc, copper, brass, stainless steel and a residual fraction. The qualities of the X-ray fluorescence output fractions were investigated by chemical analyses (precious metal fraction and the residual fraction), pyrometallurgical tests and subsequent chemical analyses of the metals and slags produced by the melting processes (zinc, copper, brass and stainless steel fraction). Screening directs brass and stainless steel primarily into the coarser fractions, while copper and residual elements were rather transferred into the finer fractions. X-ray fluorescence sorting yielded zinc, copper, brass, stainless steel and precious metals fractions in marketable qualities. Neither a negative nor a positive impact of mechanical pre-treatment on the composition of these fractions was identified. Solely the yield of the brass fraction in the grain size 16–20 mm decreased with increasing mechanical pre-treatment. The pre-treatment also had no impact on yield and quality of the products of pyrometallurgical tests.
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Thang, Sai Manh, The Nam Tran, and Duong Nam Nguyen. "Study on Microstructure and Properties of Cu-9Ni-6Sn Alloy Applied for Electric Measurement." Applied Mechanics and Materials 889 (March 2019): 17–23. http://dx.doi.org/10.4028/www.scientific.net/amm.889.17.
Повний текст джерелаАнотація:
High strength elastic alloy has an important role in the manufacture of electrical equipment and machine building. Along with the development of information and telecommunications technology, the application of this alloy in electrical and electronic equipment is very increasingly. Even on boards or connectors of common electrical equipment such as computers, cell phones, these connectors are usually made of high strength elastic copper alloy. The design required features are small, precision built, with high mechanical strength and elasticity, heat resistance, abrasion and corrosion resistance in the operating environment to ensure its/the power and signal stability for a long time. The design trend is reduced in size but still assure the equipment quality is growing significantly and the corporation to manufacture equipment is researched thoroughly. Accordingly, this article presents the research results about the alloy copper with 9%Ni and 6%Sn which has the high elastic strength and elasticity properties of elastomers after heat treatment. The properties of the microstructure, hardness, conductivity, dry friction coefficient, the corrosion resistance of the alloy from which to determine the parameters for the materials selection procedure and the design of the manufacturing of magnetic contact of this alloy. The results of the study show that after heat treatment and deformation, the Cu-9Ni-6Sn has a strength of alloy up to 1200MPa, the elastic limit is 1100MPa and the conductivity is 8.4%IACS, respectively. The values of this characteristic are consistent with the working conditions of the electrical contact. With the deformation process combined with the heat treatment process, the results of our research group created a single-phase homogeneous microstructure that is chemically stable with the spinodal decomposition in appropriate to the treatment of aging process. By modern methods, this paper demonstrates the durability of the alloy due to the spinodal decomposition during aging treatment at 350°C. This structure of spinodal decomposition is about 20-40nm in size, dispersed throughout the entire cross-section of the sample.
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Shim, Dong Woo, Yeokgu Hwang, Kwang Hwan Park, Jin Woo Lee, and Seung Hwan Han. "Long-term evaluation of Primary Osteochondral Autograft Transfer System (OATS) for large cystic type osteochondral lesion of talus." Foot & Ankle Orthopaedics 3, no. 3 (July 1, 2018): 2473011418S0044. http://dx.doi.org/10.1177/2473011418s00440.
Повний текст джерелаАнотація:
Category: Ankle Introduction/Purpose: Osteochondral lesions of talus (OLTs) are often treated primarily by fragment excision, abrasion, drilling, or microfracture. However, OLT accompanying with large cyst has been challenged to yield good outcome nevertheless of many surgical options. Recent study showed significant high failure rate of arthroscopic marrow stimulation treatment larger than 150mm2. The current study is to investigate the outcome of the primary osteochondral autograft transfer system (OATS) for large cystic type OLT (>150mm2). Methods: This retrospective analysis included 19 talus (19 patients) with diagnosed large cystic type OLT (>150mm2) who received primary OATS between September 2009 and March 2013. Defect size area was measured on magnetic resonance imaging (MRI) by the ellipse formula from coronal and sagittal length. The patients completed the visual analog scale (VAS) and the American Orthopaedic Foot & Ankle Society (AOFAS) score preoperatively and at follow-up. Plain radiographs were used to show the improvement of radiolucency postoperatively. Results: The mean follow up period was 83.9 months (57 – 99) and the average defect size area was 169.4 mm2 (151.3 – 392.6). The Mean VAS score decreased from 6.95 preoperatively to 2.6 postoperatively. Average AOFAS score improved from 66.8 preoperatively to 88.7 postoperatively. Eighty percent of patients rated their result excellent or good. The radiolucent area of the cysts disappeared on the plain radiographs in all cases. Conclusion: Long-term clinical results of primary OATS in large cystic type OLT showed good outcomes and patients could significantly benefit from this surgery.
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Liu, Xin, Hui Zhang, Hua Feng, Lei Hong, Xue-song Wang, and Guan-yang Song. "Is It Necessary to Repair Stable Ramp Lesions of the Medial Meniscus During Anterior Cruciate Ligament Reconstruction? A Prospective Randomized Controlled Trial." American Journal of Sports Medicine 45, no. 5 (January 6, 2017): 1004–11. http://dx.doi.org/10.1177/0363546516682493.
Повний текст джерелаАнотація:
Background: A special type of meniscal lesion involving the peripheral attachment of the posterior horn of the medial meniscus (PHMM), termed a “ramp lesion,” is commonly associated with an anterior cruciate ligament (ACL) injury. However, its treatment is still controversial. Recently, stable ramp lesions treated with abrasion and trephination alone have been shown to have good clinical outcomes after ACL reconstruction. Hypothesis: Stable ramp lesions treated with abrasion and trephination alone during ACL reconstruction will result in similar clinical outcomes compared with those treated with surgical repair. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: A prospective randomized controlled study was performed in 91 consecutive patients who had complete ACL injuries and concomitant stable ramp lesions of the medial meniscus. All patients were randomly allocated to 1 of 2 groups based on whether the stable ramp lesions were surgically repaired (study group; n = 50) or only abraded and trephined (control group; n = 41) during ACL reconstruction. All surgical procedures were performed by a single surgeon who was blinded to the functional assessment findings of the patients. The Lysholm score, subjective International Knee Documentation Committee (IKDC) score, and stability assessments (pivot-shift test, Lachman test, KT-1000 arthrometer side-to-side difference, and KT-1000 arthrometer differences of <3, 3-5, and >5 mm) were evaluated preoperatively and at the last follow-up. Moreover, magnetic resonance imaging (MRI) was used to evaluate the healing status of the ramp lesions. Results: All consecutive patients who were screened for eligibility from August 2008 to April 2012 were enrolled and observed clinically. There were 40 patients in the study group and 33 patients in the control group who were observed for at least 2 years. At the final follow-up, there were no significant differences between the study group and the control group in terms of the mean Lysholm score (88.7 ± 4.8 vs 90.4 ± 5.8, respectively; P = .528), mean subjective IKDC score (83.6 ± 3.7 vs 82.2 ± 4.5, respectively; P = .594), pivot-shift test results ( P = .658), Lachman test results ( P = .525), KT-1000 arthrometer side-to-side difference (1.6 ± 1.2 vs 1.5 ± 1.1, respectively; P = .853), or KT-1000 arthrometer grading ( P = .738). Overall, for both groups (n = 73), 67 patients showed completely healed (38 study, 29 control), 3 showed partially healed (1 study, 2 control), and 3 showed nonhealed (1 study, 2 control) signals on follow-up MRI when evaluating the healing status of the ramp lesions. There was no significant difference regarding the healing status of the ramp lesions between the 2 groups ( P = .543). Conclusion: This prospective randomized controlled trial showed that, in terms of subjective scores, knee stability, and meniscal healing status, concomitant stable ramp lesions of the medial meniscus treated with abrasion and trephination alone during ACL reconstruction resulted in similar clinical outcomes compared with those treated with surgical repair.
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Nurazzi, N. M., M. N. F. Norrrahim, F. A. Sabaruddin, S. S. Shazleen, R. A. Ilyas, S. H. Lee, F. N. M. Padzil, et al. "Mechanical performance evaluation of bamboo fibre reinforced polymer composites and its applications: a review." Functional Composites and Structures 4, no. 1 (March 1, 2022): 015009. http://dx.doi.org/10.1088/2631-6331/ac5b1a.
Повний текст джерелаАнотація:
Abstract This paper reviews the mechanical performance of bamboo fibre reinforced polymer composites (BFRPs) for structural applications. Bamboo fibres are very promising reinforcements for polymer composites production due to their high aspect ratio, renewability, environmentally friendly, non-toxicity, cheap cost, non-abrasives, full biodegradability, and strong mechanical performances. Besides, bamboo has its own prospects and good potential to be used in biopolymer composites as an alternative for petroleum-based materials to be used in several advanced applications in the building and construction industry. For bamboo fibre to be reinforced with polymer, they must have good interfacial bond between the polymer, as better fibre and matrix interaction results in good interfacial adhesion between fibre/matrix and fewer voids in the composite. Several important factors to improve matrix-fibre bonding and enhance the mechanical properties of BFRP are by fibre treatment, hybridisation, lamination, and using coupling agent. Moreover, mechanical properties of BFRP are greatly influenced by few factors, such as type of fibre and matrix used, fibre-matrix adhesion, fibre dispersion, fibre orientation, composite manufacturing technique used, void content in composites, and porosity of composite. In order to better understand their reinforcing potential, the mechanical properties of this material is critically discussed in this review paper. In addition, the advantages of bamboo fibres as the reinforcing phase in polymer composites is highlighted in this review paper. Besides that, the bamboo-based products such as laminated bamboo lumber, glued-laminated bamboo, hybrid bamboo polymer composites, parallel bamboo strand lumber, parallel strand bamboo, bamboo-oriented strand board, and bamboo-scrimber have lately been developed and used in structural applications.
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Sofka, Carolyn, Taylor Cabe, Jonathan Deland, Mark Drakos, and Karan Patel. "A Comparison of Functional and Radiographic Outcomes following Microfracture with Extracellular Matrix Augmentation versus Osteochondral Autograft Transplantation for the Treatment of Medium-Sized Osteochondral Lesions of the Talus." Orthopaedic Journal of Sports Medicine 8, no. 7_suppl6 (July 1, 2020): 2325967120S0038. http://dx.doi.org/10.1177/2325967120s00387.
Повний текст джерелаАнотація:
Objectives: The aim of this study is to directly compare clinical outcomes following the treatment of medium-sized osteochondral lesions of the talus (OLTs) using a microfracture technique augmented with Extracellular Matrix and Bone Marrow Aspirate Concentrate (MFX) versus OAT to determine which treatment is superior for medium-sized lesions. Methods: Patients treated for an OLT between 2015 and 2018 by a single surgeon, fellowship-trained in sports medicine and foot and ankle, were screened for this study. Retrospective chart review determined treatment, lesion size, lesion location, concurrent injuries, and demographic information. Patients at a minimum of 12 months follow-up, treated with MFX or OAT, and lesions sized 80-165mm2 were eligible for inclusion. All surgical repairs were augmented with an adjuvant mixture of micronized cartilage extracellular matrix and bone marrow aspirate concentrate (ECM-BMAC). Patient-reported functional outcomes were collected through our institution’s prospective Registry database. Patients treated prior to March 2016 were administered preoperative Foot and Ankle Outcome Score questionnaires. Those treated after this date were administered preoperative Physical Function, Pain Interference, Global Physical Health, Global Mental Health, Depression, and Pain Intensity Patient-Reported Outcome Information System (PROMIS) domains. Both FAOS and PROMIS were administered postoperatively. Postoperative MRIs were assessed using a modified magnetic resonance observation of cartilage repair tissue (MOCART) score. Student’s paired and two-group t-tests were used to evaluate for statistically significant pre-to-postoperative change and differences between procedure groups (p less than 0.05). Results: Twenty-seven patients treated with MFX (age range, 14-58) and twenty-three patients treated using OAT (age range, 22-64) were identified. All OAT patients received a single-plug transplantation. The final average lesion size ± standard deviation (SD) for patients treated with MFX was 115.44mm2± 22.51 (range, 156-80mm2) and 121.78mm2± 23.98 (range, 165-80mm2) for those treated using OAT (p=0.34). On average, functional outcome scores improved pre-to-postoperatively across all scales within both groups. Statistically significant improvements were detected in PROMIS Physical Function (Δ=8.32, p=0.01), Pain Interference (Δ=-7.15, p=0.02), Global Physical Health (Δ=5.87, p=0.03), and Pain Intensity (Δ=-7.06, p=0.05) domains for the MFX cohort. For the OAT patient group, significant pre-to-postoperative change was seen in the FAOS subcategories of Pain (Δ=28.70, p=0.03), Sports Activities (Δ=43.12, p<0.01), and Quality of Life (Δ=43.75, p=0.01); overall FAOS score (Δ=29.93, p=0.01); and PROMIS Physical Function (Δ=13.66, p=0.01), Pain Interference (Δ=-14.58, p<0.01), Global Physical Health (Δ=12.2, p=0.01), Depression (Δ=-4.13, p=0.02), and Pain Intensity (Δ=-16.56, p=0.02) domains. On average, with the exception of the postoperative Sports Activities subscale, postoperative FAOS and pre-to-postoperative change in FAOS were higher and greater in the OAT patient group. Similarly, on average, the OAT group had better PROMIS t-scores indicating higher function or less pain and greater pre-to-postoperative change in each PROMIS domain. The OAT cohort’s average postoperative Pain Interference t-score (± SD) of 43.09 (± 5.81) and Depression t-score of 40.06 (± 6.84) were significantly lower than their respective counterparts in the MFX cohort: 50.08 (± 9.47) for Pain Interference and 48.09 (± 7.86) in Depression. (Table 1) Finally, the mean overall MOCART score was 55.67 (± 24.11) within the MFX cohort, average follow-up 15.29 months, and 71 (± 15.60) within the OAT cohort average follow-up 15.8 months. This difference was also statistically significant (p=0.04). Conclusion: The OAT group had a higher MOCART score indicating the use of a single osteochondral autograft plug may result in better structural repair than microfracture abrasion chondroplasty augmented with a mixture of adjuvant ECM-BMAC. In addition, higher average FAOS scores, better average PROMIS t-scores, and greater pre-to-postoperative change in the OAT patient group indicate functional results may be better in this group as well. Specifically, significantly lower Pain Interference and Depression domains and significantly higher Global Mental Health scores indicate patients treated using OAT experience less pain and better psychological benefits postoperatively compared to patients treated using MFX. These results suggest filling the lesion with transplanted autograft bone and native, hyaline cartilage may perform better than and the biomechanically inferior fibrocartilage produced following microfracture even when augmented with adjuvant therapy. OAT may result in better overall clinical outcomes, specifically in a population of patients with medium sized lesions (range, 80 mm2 -165 mm2).
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Chizhik, S. A., L. M. Akulovich, M. L. Kheifetz, S. A. Klimenko, V. I. Lavrinenko, V. S. Mayboroda, A. I. Dikusar, S. Ivascu, and N. Kazak. "Combined method of hardening and finishing abrasive treatment of parts surfaces in magnetic field." Strengthening Technologies and Coatings, 2021, 509–19. http://dx.doi.org/10.36652/1813-1336-2021-17-11-509-519.
Повний текст джерелаАнотація:
Method and technologies of coating metal surfaces by electric spark discharges with subsequent hardening abrasive treatment in a magnetic field are considered. The possibilities of increasing the wear resistance of metal surfaces by joint method of alloying the surface layer of the part and reducing its roughness are shown. Mathematical models of these processes have been developed, which make it possible to optimize the technologies of hardening coatings.
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Li, Kun, Ruijin Ma, Ming Zhang, Wen Chen, Xiaobin Li, David Z. Zhang, Qian Tang, Lawrence E. Murr, Jinfeng Li, and Huajun Cao. "Hybrid post-processing effects of magnetic abrasive finishing and heat treatment on surface integrity and mechanical properties of additively manufactured Inconel 718 superalloys." Journal of Materials Science & Technology, May 2022. http://dx.doi.org/10.1016/j.jmst.2022.03.026.
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"Electric-Spark Alloying of Metal Surfaces with Graphite." Progress in Physics of Metals 23, no. 1 (March 2022): 27–58. http://dx.doi.org/10.15407/ufm.23.01.027.
Повний текст джерелаАнотація:
The article reviews and analyses the current scientific research in the field of surface treatment of metal surfaces with concentrated energy fluxes (CEF) — the electric-spark (in the literature, known also as electrospark) alloying (ESA), which makes it possible to obtain surface structures with unique physical, mechanical and tribological properties at the nanoscale. The ESA method with a graphite electrode (electrospark carburizing — EC) is based on the process of diffusion (saturation of the surface layer of a part with carbon), and it is not accompanied by an increase in the size of the part. In this article, the influence of the EC parameters on the quality of the carburized layer is investigated. The microstructural analysis shows that the three characteristic zones could be distinguished in the structure: the carburized (‘white’) layer, the finely dispersed transition zone with fine grain, and the base metal zone. The analysis of the results of the durometric studies of the coatings is carried out. To achieve the required parameters of dimensional accuracy and roughness of the working surface of the part after the EC process, it is necessary to use the method of non-abrasive ultrasonic finishing (NAUF). In addition, because of applying the NAUF method, the surface roughness is decreased, the tensile stresses are changed to the compressive ones, and the fatigue strength is increased too. In addition, to reduce the roughness of the treated surface, it is proposed to apply the EC technology in stages, reducing the energy of the spark discharge at each subsequent stage. In order to increase the quality of the carburized layer obtained by the EC process, it is proposed to use a graphite powder, which is applied to the treated surface before alloying. The comparative analysis shows that, after the traditional EC process at Wp = 4.6 J, the surface roughness of steel 20 is Ra = 8.3–9.0 μm, and after the proposed technology, Ra = 3.2–4.8 μm. In this case, the continuity of the alloyed layer increases up to 100%; there increases the depth of the diffusion zone of carbon up to 80 μm as well as the microhardness of the ‘white’ layer and its thickness, which increase up to 9932 MPa and up to 230 μm, respectively. The local micro-x-ray spectral analysis of the obtained coatings shows that, at the EC process carried out in a traditional way, the applying Wp = 0.9, 2.6, 4.6 J provides the formation of the surface layers with high-carbon content depths of 70, 100, 120 μm, respectively, and with the use of a graphite powder, they are of 80, 120, 170 μm. While deepening, the amount of carbon is decreasing from 0.72–0.86% to the carbon content in the base metal — 0.17–0.24%. In the near-surface layer formed with the use of the new technology, the pores are filled with free graphite, which could be used as a solid lubricant to improve the operating characteristics of the friction-pairs parts processed thereby.
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Moreira, José, Margarida Almeida, Nuno Lunet, and Manuel Gutierres. "Ramp lesions: a systematic review of MRI diagnostic accuracy and treatment efficacy." Journal of Experimental Orthopaedics 7, no. 1 (September 25, 2020). http://dx.doi.org/10.1186/s40634-020-00287-x.
Повний текст джерелаАнотація:
Abstract Purpose We conducted a systematic review of the published literature to assess the accuracy of Magnetic Resonance Imaging (MRI) in establishing the presence of ramp lesions (RLs) in Anterior Cruciate Ligament (ACL) deficient knees and the clinical efficacy of the surgical repair of RLs. Methods A comprehensive search of the MEDLINE, Web of Science and Scopus databases was performed according to PRISMA guidelines. Studies assessing MRI diagnostic accuracy for RLs or the clinical effect of RL repair in participants with ACL injuries were included. Diagnostic accuracy measures were pooled and plotted in forest plots. Preoperative and at last follow-up treatment efficacy outcome measures were extracted and plotted in forest plots, for graphical comprehension. Results Sixteen studies met the criteria and were included. The diagnostic analysis showed a pooled sensitivity, specificity, positive and negative likelihood ratios of 65.1% (95% CI, 59.73 to 70.42), 91.6% (95% CI, 89.14 to 94.05), 2.91 (95% CI, 2.38–3.55) and 0.53 (95% CI, 0.44–0.64), respectively, with high heterogeneity (I2 above 80%) for all measures. Treatment analysis showed improved Lysholm Knee Score, IKDC score and laxity difference between the knees in all studies after meniscal suture repair. A separate analysis showed no differences between repair of smaller, stable, RLs with meniscal sutures and repair with abrasion and trephination only. Conclusion Although the results present considerable heterogeneity, MRI seems to demonstrate moderate accuracy in the diagnosis of RLs in patients with ACL tear and the surgical repair of RLs can be associated with improved overall outcomes.