A novel technique for the development of acetabular cup by cold isostatic compaction and sintering of UHMWPE powder with optimized processing parameters

2021 ◽  
Author(s):  
Ashirbad Jana ◽  
Senthilvelan Selvaraj ◽  
Kanagaraj Subramani
Keyword(s):  
Processing Parameters ◽  
Acetabular Cup ◽  
Novel Technique ◽  
Isostatic Compaction

scholarly journals Laser Surface Texturing of Alumina/Zirconia Composite Ceramics for Potential Use in Hip Joint Prosthesis

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 369 ◽  
Author(s):  
Francesco Baino ◽  
Maria Angeles Montealegre ◽  
Joaquim Minguella-Canela ◽  
Chiara Vitale-Brovarone
Keyword(s):  
Hip Joint ◽  
Surface Texturing ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Laser Surface Texturing ◽  
Joint Prosthesis ◽  
Composite Ceramics ◽  
Acetabular Cup ◽  
Repetition Number ◽  
Number Of Cycles

The use of metal shell to fix an acetabular cup to bone in hip joint prosthesis carries some limitations, including restrictions in prosthetic femur ball diameter and in patient’s range of motion. These drawbacks could be ideally overcome by using a monolithic ceramic acetabular cup, but the fixation of such an implant to host bone still remains a challenge. Since porous surfaces are known to promote more bone tissue interlocking compared to smooth materials, in this work the surfaces of sintered alumina/zirconia composite ceramics were treated by a pulsed laser radiation at 1064 nm with a pulse width in the nanosecond range, in order to impart controlled textural patterns. The influence of laser process parameters (e.g., energy per pulse, repetition rate, scanning speed, repetition number, angle of laser beam, and number of cycles) on the roughness and texture orientation was systematically investigated. The obtained surface topographies were inspected by optical and scanning electron microscopy, and the roughness was assessed by contact profilometry. Surface roughness could be modulated in the range of 3 to 30 µm by varying the processing parameters, among which the number of cycles was shown to play a major role. The laser treatment was also successfully adapted and applied to ceramic acetabular cups with a curved profile, thus demonstrating the feasibility of the proposed approach to process real prosthetic components.

Effects of Grain Refiner on the Microstructural Evolution during Making Semi-Solid Slurry of the A357 Alloy

2016 ◽  
Vol 256 ◽  
pp. 88-93 ◽  
Author(s):  
Xiao Kang Liang ◽  
Da Quan Li ◽  
Min Luo ◽  
You Feng He ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Microstructural Evolution ◽  
Processing Parameters ◽  
Thermal Capacity ◽  
Grain Structure ◽  
Homogeneous Distribution ◽  
Grain Refiner ◽  
A357 Alloy ◽  
Novel Technique ◽  
Semi Solid ◽  
Slurry Preparation

The enthalpy equilibration method is a novel technique to produce globular grain structure in semi-solid slurry preparation. In this process, the liquid is firstly poured into a metallic crucible, which possesses low thermal conductivity and high thermal capacity. Homogeneous distribution of temperature within the metallic crucible is achieved by rotating the crucible and cold down to a temperature between liquidus and solidus, determined by the requirement of solid fraction. The semi-solid slurry is then transferred to a high pressure die caster. In order to achieve a spherical microstructure morphologies in the entire slurry, effects of grain refiners, in addition to the enthalpy equilibration method, on the microstructure of the slurries of A357 alloy were investigated. Quantitative metallographic measurements were applied to evaluate microstructural evolution and processing parameters were optimized.

scholarly journals Sustainable approach toward synthesis of green functional carbonaceous 3-D micro/nanostructures from biomass

2021 ◽  
Author(s):  
Amirhossein Tavangar ◽  
Bo Tan ◽  
Krishnan Venkatakrishnan
Keyword(s):  
Laser Processing ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Single Step ◽  
Femtosecond Laser Irradiation ◽  
Ambient Conditions ◽  
Step Process ◽  
Novel Technique ◽  
Electronic Sensing ◽  
By Products

This study proposes a novel technique to synthesize functional carbonaceous three-dimensional (3-D) micro/ nanocompounds from agricultural by-products using femtosecond laser irradiation. Biowastes of rice husk and wheat straw are value-engineered to carbonaceous structures in a single-step process under ambient conditions. Our results demonstrate that by controlling the laser fluence, structures with a variety of different morphologies from nanostructures to microstructures can be achieved. Also, the results indicate that altering the laser processing parameters influences the chemical composition of the synthesized structures. This sustainable approach presents an important step towards synthesizing 3-D micro/nanofibrous compounds from biowaste materials. These structures, as-synthesized or as nanocomposite fillers, can have practical uses in electronic, sensing, biological, and environmental applications.

scholarly journals Mini-Thixoforming of a Steel Produced by Powder Metallurgy

2012 ◽  
Vol 192-193 ◽  
pp. 500-505 ◽  
Author(s):  
Hana Jirková ◽  
David Aišman ◽  
Indrani Sen ◽  
Martin F.X. Wagner ◽  
Mária Behúlová ◽  
...  
Keyword(s):  
High Hardness ◽  
Processing Parameters ◽  
Powder Steel ◽  
New Materials ◽  
Metastable Austenite ◽  
Technical Problems ◽  
Carbide Network ◽  
Novel Technique ◽  
Semi Solid ◽  
Material Powder

Semi-solid processing is complicated by various inherent technical problems. However, once these problems are solved, thixoforming allows intricately shaped components to be manufactured very effectively – often with microstructures that cannot be produced by any other techniques. The recently introduced mini-thixoforming method is an example of such a novel technique for semi-solid processing of steel. The wall thicknesses of resulting parts are about 1 mm. Microstructures of semi-solid-processed steels typically consist of a high proportion of globular particles of metastable austenite embedded in a carbide network, the latter being much harder and more brittle. This paper illustrates that mini-thixoforming allows inverting that microstructural configuration. As an experimental material, powder steel with increased content of vanadium and chromium was used. The post-thixoforming microstructure consisted of a dispersion of carbides and high-vanadium and high-chromium eutectic in an austenitic matrix. Applying optimised processing parameters, complex-shaped parts could be produced. According to the high hardness of resulting microstructural components, the new materials are likely to exhibit extraordinary strength and wear resistance.

scholarly journals Sustainable approach toward synthesis of green functional carbonaceous 3-D micro/nanostructures from biomass

2021 ◽  
Author(s):  
Amirhossein Tavangar ◽  
Bo Tan ◽  
Krishnan Venkatakrishnan
Keyword(s):  
Laser Processing ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Single Step ◽  
Femtosecond Laser Irradiation ◽  
Ambient Conditions ◽  
Step Process ◽  
Novel Technique ◽  
Electronic Sensing ◽  
By Products

This study proposes a novel technique to synthesize functional carbonaceous three-dimensional (3-D) micro/ nanocompounds from agricultural by-products using femtosecond laser irradiation. Biowastes of rice husk and wheat straw are value-engineered to carbonaceous structures in a single-step process under ambient conditions. Our results demonstrate that by controlling the laser fluence, structures with a variety of different morphologies from nanostructures to microstructures can be achieved. Also, the results indicate that altering the laser processing parameters influences the chemical composition of the synthesized structures. This sustainable approach presents an important step towards synthesizing 3-D micro/nanofibrous compounds from biowaste materials. These structures, as-synthesized or as nanocomposite fillers, can have practical uses in electronic, sensing, biological, and environmental applications.

scholarly journals Sustainable approach toward synthesis of green functional carbonaceous 3-D micro/nanostructures from biomass

2021 ◽  
Author(s):  
Amirhossein Tavangar ◽  
Bo Tan ◽  
Krishnan Venkatakrishnan
Keyword(s):  
Laser Processing ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Single Step ◽  
Femtosecond Laser Irradiation ◽  
Ambient Conditions ◽  
Step Process ◽  
Novel Technique ◽  
Electronic Sensing ◽  
By Products

This study proposes a novel technique to synthesize functional carbonaceous three-dimensional (3-D) micro/ nanocompounds from agricultural by-products using femtosecond laser irradiation. Biowastes of rice husk and wheat straw are value-engineered to carbonaceous structures in a single-step process under ambient conditions. Our results demonstrate that by controlling the laser fluence, structures with a variety of different morphologies from nanostructures to microstructures can be achieved. Also, the results indicate that altering the laser processing parameters influences the chemical composition of the synthesized structures. This sustainable approach presents an important step towards synthesizing 3-D micro/nanofibrous compounds from biowaste materials. These structures, as-synthesized or as nanocomposite fillers, can have practical uses in electronic, sensing, biological, and environmental applications.

scholarly journals Sustainable approach toward synthesis of green functional carbonaceous 3-D micro/nanostructures from biomass

2021 ◽  
Author(s):  
Amirhossein Tavangar ◽  
Bo Tan ◽  
Krishnan Venkatakrishnan
Keyword(s):  
Laser Processing ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Single Step ◽  
Femtosecond Laser Irradiation ◽  
Ambient Conditions ◽  
Step Process ◽  
Novel Technique ◽  
Electronic Sensing ◽  
By Products

This study proposes a novel technique to synthesize functional carbonaceous three-dimensional (3-D) micro/ nanocompounds from agricultural by-products using femtosecond laser irradiation. Biowastes of rice husk and wheat straw are value-engineered to carbonaceous structures in a single-step process under ambient conditions. Our results demonstrate that by controlling the laser fluence, structures with a variety of different morphologies from nanostructures to microstructures can be achieved. Also, the results indicate that altering the laser processing parameters influences the chemical composition of the synthesized structures. This sustainable approach presents an important step towards synthesizing 3-D micro/nanofibrous compounds from biowaste materials. These structures, as-synthesized or as nanocomposite fillers, can have practical uses in electronic, sensing, biological, and environmental applications.

A Novel Technique for PAR Reduction in DRM

2012 ◽  
Vol 546-547 ◽  
pp. 1329-1333
Author(s):  
Wei Zhang Xu ◽  
Zhan Xin Yang ◽  
Xin Le Yu
Keyword(s):  
Root Mean Square ◽  
Average Power ◽  
Processing Parameters ◽  
Signal Quality ◽  
Power Ratio ◽  
Mean Square ◽  
Quality Requirements ◽  
Novel Technique ◽  
Rf Signal ◽  
The Impact

PAR (Peak-to-Average Power Ratio) is one of significant issues in a DRM transmitter. To reduce the PAR of DRM signals, an iterative pre-distortion technique is proposed in this paper. This technique improves the RMS (Root Mean Square) power of transmitter while the effect on DRM signal quality is negligible. Research has been done on the impact that the processing parameters caused to DRM signal quality. Simulation and test indicate that in the case that the quality requirements for the RF signal in the DRM specification is satisfied, DRM output power is increased to 9kw from 5kw (RMS power) based on a 10kw (carrier power) DX transmitter, thereby improving the capability of the transmitter greatly.

Microstructural Variations in Melt-Spun Rapidly Solidified Ribbons

1985 ◽  
Vol 43 ◽  
pp. 54-55
Author(s):  
L. A. Bendersky ◽  
W. J. Boettinger
Keyword(s):  
Solid State ◽  
Processing Parameters ◽  
Heat Extraction ◽  
Solid State Reactions ◽  
Careful Examination ◽  
Ion Milling ◽  
Melt Spun ◽  
Wheel Side ◽  
Rapidly Solidified ◽  
Heat Extraction Rate

Rapid solidification produces a wide variety of sub-micron scale microstructure. Generally, the microstructure depends on the imposed melt undercooling and heat extraction rate. The microstructure can vary strongly not only due to processing parameters changes but also during the process itself, as a result of recalescence. Hence, careful examination of different locations in rapidly solidified products should be performed. Additionally, post-solidification solid-state reactions can alter the microstructure.The objective of the present work is to demonstrate the strong microstructural changes in different regions of melt-spun ribbon for three different alloys. The locations of the analyzed structures were near the wheel side (W) and near the center (C) of the ribbons. The TEM specimens were prepared by selective electropolishing or ion milling.

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