New Pathways to Processing Composites

1988 ◽  
Vol 120 ◽  
Author(s):  
Robert Mehrabian
Keyword(s):  
Powder Metallurgy ◽  
Design Principles ◽  
Processing Pathways ◽  
Melt Infiltration ◽  
Microstructural Design ◽  
Processing Techniques

AbstractCompositing routes are reviewed for the fabricaiton of metal and metalceramic matrices combined with ceramic reinforcements and/or ductilizing phases. The important role of micromechanics in elucidating microstructural design principles to guide the processing “pathways” is emphasized. Specific processing techniques are described including incorporation of particles and fibers into melts, melt infiltration into preforms, powder metallurgy and melt oxidation.

scholarly journals Role of carbon and nitrogen in the improvement of corrosion resistance of new powder metallurgy Co-Cr-Mo alloys

2020 ◽  
Vol 38 (3) ◽  
pp. 273-286 ◽  
Author(s):  
Cristina Garcia-Cabezon ◽  
Celia Garcia-Hernandez ◽  
Maria L. Rodriguez-Mendez ◽  
Gemma Herranz ◽  
Fernando Martin-Pedrosa
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Nitrogen Content ◽  
Powder Metallurgy Technique ◽  
Carbon And Nitrogen ◽  
Physiological Conditions ◽  
Carbon And Nitrogen Content ◽  
Astm F75

AbstractMicrostructural changes that result in relevant improvements in mechanical properties and electrochemical behavior can be induced using different sintering conditions of ASTM F75 cobalt alloys during their processing using powder metallurgy technique. It has been observed that the increase in carbon and nitrogen content improves corrosion resistance and mechanical properties as long as the precipitation of carbides and nitrides is avoided, thanks to the use of rapid cooling in water after the sintering stage. In addition, the reduction of the particle size of the powder improves hardness and resistance to corrosion in both acid medium with chlorides and phosphate-buffered medium that simulates the physiological conditions for its use as a biomaterial. These results lead to increased knowledge of the role of carbon and nitrogen content in the behavior displayed by the different alloys studied.

Mechanical properties of melt infiltration and powder metallurgy fabricated aluminum metal matrix composite

2021 ◽  
pp. 095440542110159
Author(s):  
Mahmoud Awad ◽  
Noha M Hassan ◽  
Sathish Kannan
Keyword(s):  
Powder Metallurgy ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Composite Foam ◽  
Space Holder ◽  
Aluminum Metal Matrix Composite ◽  
Melt Infiltration ◽  
Innovative Material ◽  
And Coping

Metal foams have drawn an increasing interest especially in applications where weight and energy absorption are critical. Despite the extensive studies available on their characterization and enhanced fabrication techniques, limited work was found on the possibility of producing a porous composite foam. The objective of this article is to investigate two new synthesis techniques for manufacturing metal matrix composite foam that is, powder metallurgy and melt infiltration. Both techniques are studied using Sodium Chloride (NaCl) as a space holder in an aluminum-based metal matrix and graphene nanoparticles as reinforcements. The effect of the quantity added of both the space holder and graphene is studied using designed experiments. Although powder metallurgy provided lower baseline hardness, experimentation results suggest the superiority of the process over melt infiltration in terms of porosity and hardness. Results suggest that baseline aluminum hardness can be increased by up to 21.5% using powder metallurgy and 15% using melt infiltration. In terms of porosity, powder metallurgy porosity increased baseline more than ten folds while melt infiltration only doubled the baseline porosity. Moreover, it is easier to control the macroscopic shape, density, and distribution of the pores using powder metallurgy. It is also easier to disperse the reinforcement homogenously. Results will support several industries such as military, automotive, medical, and aerospace in developing this innovative material with superior properties and coping with their need for advanced applications.

The Emerging Role of Nanosuspensions for Drug Delivery and Stability

2021 ◽  
Vol 12 ◽  
Author(s):  
Hitesh Kumar Dewangan
Keyword(s):  
Water Solubility ◽  
Size Range ◽  
Aqueous Solubility ◽  
Active Surface ◽  
Water Soluble ◽  
Active Surface Area ◽  
Specific Interest ◽  
Advanced Therapies ◽  
Processing Techniques

: Poor solubility of some medicinal compounds is a serious challenge that can be addressed by using a nano-suspension for improved delivery. The nanoparticles enhance the bioavailability along with the aqueous solubility of the drug, which is accomplished by increasing the active surface area of the drug. The gained attention of the nanosuspension is due to its stabilization facility, which is achieved by polymers, such as polyethylene glycol (PEG), having a particular size range of 10 - 100 nm. Hence, these nanoparticles have the capacity of binding to the targeted with very low damage to the healthy tissues. These are prepared by various methods, such as milling, high-pressure homogenization, and emulsification, along with melt emulsification. Moreover, surface modification and solidification have been used to add specific properties to the advanced therapies as post-processing techniques. For many decades, it has been known that water solubility hampers the bioavailability and not all drugs are water-soluble. In order to combat this obstacle, nanotechnology has been found to be of specific interest. For elevating the bioavailability by increasing the dissolution rate, the methodology of reduction of the associated drug particles into their subsequent submicron range is incorporated. For oral and non-oral administration, these nanosuspension formulations are used for the delivery of drugs.

IVUS Image Processing Methodologies

2013 ◽  
pp. 639-657
Author(s):  
Antonis A. Sakellarios ◽  
Christos V. Bourantas ◽  
Lambros S. Athanasiou ◽  
Dimitrios I. Fotiadis ◽  
Lampros K. Michalis
Keyword(s):  
Image Processing ◽  
Vessel Wall ◽  
Regions Of Interest ◽  
Manual Segmentation ◽  
Arterial Lumen ◽  
Ivus Image ◽  
Processing Techniques ◽  
Automated Methods

Intravascular Ultrasound (IVUS) is an invasive imaging technique that allows detailed visualization of the arterial lumen and outer vessel wall and permits characterization of the type of the plaque and quantification of its burden. Traditionally IVUS processing was performed manually. However, it became apparent that manual segmentation is time consuming, and the obtained results depend on the experience of the operators. To overcome these limitations and enhance the role of IVUS in clinical practice and research, several (semi-) automated methods have been developed that expedite detection of the regions of interest and/or characterization of the type of the plaque. In this chapter we review the available IVUS processing techniques and present the developed commercial solutions for IVUS segmentation and plaque characterization.

scholarly journals Physical and thermal properties of l‐ lactide/ϵ‐caprolactone copolymers: the role of microstructural design

2019 ◽  
Vol 69 (3) ◽  
pp. 248-256 ◽  
Author(s):  
Sawarot Phetsuk ◽  
Robert Molloy ◽  
Kanarat Nalampang ◽  
Puttinan Meepowpan ◽  
Paul D Topham ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Microstructural Design

Treating faecal sludges in ponds

2000 ◽  
Vol 42 (10-11) ◽  
pp. 283-290 ◽  
Author(s):  
M. Strauss ◽  
S. A. Larmie ◽  
U. Heinss ◽  
A. Montangero
Keyword(s):  
Field Research ◽  
Design Principles ◽  
Water Research ◽  
Waste Stabilisation Ponds ◽  
Pond System ◽  
Anaerobic Degradability ◽  
Research Institute

Waste stabilisation ponds are a widely accepted and proven technology to treat wastewater. It is often stipulated (and also practised) that the design of ponds for faecal sludges (FS), septage in particular, should follow the same principles as for wastewater. Field research conducted by SANDEC and its partners at the Water Research Institute in Ghana, and information gathered from the scarce literature on FS treatment, however, has shown that design principles should be taken into consideration, which are specific to the treatment of FS. These principles depend on the type of FS to be treated and on the type of pond system envisaged. Issues dealt with in this article are the handling of FS solids; the role of anaerobic ponds in FS treatment; the anaerobic degradability of septage; and ammonia (NH3–N) toxicity.

Does open access citation advantage depend on paper topics?

2019 ◽  
Vol 46 (5) ◽  
pp. 696-709
Author(s):  
Hajar Sotudeh
Keyword(s):  
Open Access ◽  
Language Processing ◽  
Analysis Method ◽  
Research Topics ◽  
Abstract Level ◽  
Article Processing Charges ◽  
Processing Techniques ◽  
Citation Advantage ◽  
Selection Of

Research topics vary in their citation potential. In a metric-wise scientific milieu, it would be probable that authors tend to select citation-attractive topics especially when choosing open access (OA) outlets that are more likely to attract citations. Applying a matched-pairs study design, this research aims to examine the role of research topics in the citation advantage of OA papers. Using a comparative citation analysis method, it investigates a sample of papers published in 47 Elsevier article processing charges (APC)-funded journals in different access models including non-open access (NOA), APC, Green and mixed Green-APC. The contents of the papers are analysed using natural language processing techniques at the title and abstract level and served as a basis to match the NOA papers to their peers in the OA models. The publication years and journals are controlled for in order to avoid their impacts on the citation numbers. According to the results, the OA citation advantage that is observed in the whole sample still holds even for the highly similar OA and NOA papers. This implies that the OA citation surplus is not an artefact of the OA and NOA papers’ differences in their topics and, therefore, in their citation potential. This leads to the conclusion that OA authors’ self-selectivity, if it exists at all, is not responsible for the OA citation advantage, at least as far as selection of topics with probably higher citation potentials is concerned.

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