Processing of Polymer-Derived Microcellular Ceramics Containing Reactive Fillers

2007 ◽  
Vol 534-536 ◽  
pp. 989-992 ◽  
Author(s):  
Young Wook Kim ◽  
Doo Hee Jang ◽  
Jung Hye Eom ◽  
In Hyuck Song ◽  
Hai Doo Kim
Keyword(s):  
Silicon Carbide ◽  
Cell Size ◽  
Cell Density ◽  
Reaction Method ◽  
Novel Processing ◽  
Cell Densities ◽  
Cordierite Ceramics ◽  
Processing Techniques ◽  
Study Offer

Processing techniques for producing microcellular silicon carbide, mullite, and cordierite ceramics with cell densities greater than 108 cells/cm3 and cells smaller than 30 μm have been developed by a reaction method that incorporates a polysiloxane and reactive fillers. The techniques developed in this study offer substantial flexibility for producing microcellular ceramics whereby cell size, cell density, degree of interconnectivity, composition, and porosity can all be effectively controlled. It is demonstrated that the adjustment of filler composition enables the possibility of tailoring the composition and properties of the microcellular ceramics. The present results suggest that the proposed novel processing techniques are suitable for the manufacture of microcellular ceramics with high morphological uniformity.

Increasing cell density/decreasing cell size to produce microcellular and nanocellular thermoplastic foams: A review

2020 ◽  
pp. 0021955X2095930
Author(s):  
Taher Azdast ◽  
Rezgar Hasanzadeh
Keyword(s):  
Cell Size ◽  
Cell Density ◽  
Low Cost ◽  
Weight Ratio ◽  
High Strength ◽  
Batch Process ◽  
Efficient Solutions ◽  
Sound Insulation ◽  
Polymeric Foams ◽  
Cell Densities

Nowadays, polymeric foams have attracted particular attention in scientific and industrial societies due to their unique properties, such as high strength to weight ratio, excellent thermal and sound insulation, and low cost. Researchers have shown that the extraordinary properties of polymeric foams such as superior thermal insulation, can be achieved by increasing the cell density/decreasing the cell size. In this regard, firstly, the most important foaming processes, i.e. batch, extrusion, and injection molding are studied in the present research. Then, cell nucleation stage as the most crucial phenomenon for achieving high cell density/small cell size is investigated in detail. In the next step, the most important researches in the field of polymeric foams are introduced in which the largest cell densities/smallest cell sizes have been achieved. The investigations show that the most remarkable results (highest cell densities/smallest cell sizes) belong to the batch process. Also, the use of nucleating agents, increasing the solubility of blowing agent into the polymer, and the use of nanoparticles are the most efficient solutions to achieve microcellular and nanocellular structures.

Processing Techniques of a Silicon Carbide Heat Exchanger and its Capable Properties – A Review

2015 ◽  
Vol 787 ◽  
pp. 513-517 ◽  
Author(s):  
R. Pachaiyappan ◽  
R. Gopinath ◽  
S. Gopalakannan
Keyword(s):  
Silicon Carbide ◽  
Heat Exchanger ◽  
Gas Turbines ◽  
Cooling System ◽  
Composite Ceramic ◽  
Processing Technique ◽  
Full Potential ◽  
Absorption Chillers ◽  
Evaporative Cooling System ◽  
Processing Techniques

Silicon carbides is a composite ceramic material produced from inorganic non-metallic substances, formed from the molten mass which solidifies on cooling and simultaneously matured by the action of heat. It is used in various applications such as grinding wheels, filtration of gases and water, absorption, catalyst supports, concentrated solar powers, thermoelectric conversion etc. The modern usage of silicon carbide is fabricated as a heat exchanger for high temperature applications. Leaving behind steel and aluminium, silicon carbide has an excellent temperature withstanding capability of 1425°C. It is resistant to corrosion and chemical erosion. Modern fusion reactors, Stirling cycle based gas turbines, evaporators in evaporative cooling system for air condition and generator in LiBr/H2O absorption chillers for air conditioning those systems heat transfer rate can be improved by replacing a present heat exchanger with silicon carbide heat exchanger. This review presents a detailed discussion about processing technique of such a silicon carbide. Modern known processing techniques are partial sintering, direct foaming, replica, sacrificial template and bonding techniques. The full potential of these materials can be achieved when properties are directed over specified application. While eyeing over full potential it is highly dependent on processing techniques.

High Tc Oxide Superconductors

MRS Bulletin ◽  
1990 ◽  
Vol 15 (6) ◽  
pp. 31-33
Author(s):  
M. Brian Maple
Keyword(s):  
Physical Properties ◽  
Energy Gap ◽  
Vortex State ◽  
Oxide Superconductors ◽  
High Tc ◽  
Superconducting Energy Gap ◽  
Consistent Picture ◽  
Novel Processing ◽  
Processing Techniques

This issue of the MRS BULLETIN is devoted to high Tc superconductivity. It is the sequel to a previous series of articles on the same subject which appeared in the MRS BULLETIN in January 1989. While the articles in the January 1989 issue emphasized the families of high Tc superconducting oxides known at that rime, as well as novel processing techniques and thin films, the papers in this issue focus on the physical properties of high Tc oxide superconductors.The quality of polycrystalline and single-crystal bulk and thin-film materials has improved to the point where researchers can now make reliable measurements of many physical properties representative of the intrinsic behavior of these materials. As a result, a broad spectrum of important issues such as the nature of the electronic structure, the type of superconducting electron pairing, the magnitude and temperature dependence of the superconducting energy gap, the behavior of fluxoids in the vortex state, etc., can be addressed meaningfully. Presently emerging is a consistent picture of the physical properties of the high Tc oxides, which will form the foundation to eventually developing an appropriate theory for the normal and superconducting states of these remarkable materials.

The Effect of SiC Surface Treatment on the Interface Bonding Behavior of SiC/Cu Composite Particles

2012 ◽  
Vol 512-515 ◽  
pp. 951-954
Author(s):  
Bing Bing Fan ◽  
Huan Huan Guo ◽  
Jian Li ◽  
Hai Long Wang ◽  
Ke Bao ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Surface Treatment ◽  
Practical Importance ◽  
Functional Materials ◽  
Decomposition Reaction ◽  
Reduction Reaction ◽  
Temperature Oxidation ◽  
Reaction Method ◽  
Silicon Carbide Particles ◽  
Carbide Particles

The SiC/Cu composite is one of the "structural-functional" materials. It shows good mechanical properties and very high thermal, high electrical conductivity etc. But the co-dispersion, wetting and bonding between SiC and Cu interface are of practical importance in the preparation of SiC/Cu composites. In this work, surface treatment techniques such as high-temperature oxidation, acid dipping and alkaline wash were adopted separately on silicon carbide particles, in order to improve the wettability and physical and chemical compatibility between silicon carbide and copper, then we used the replacement reaction method and decomposition-reduction reaction method to generate Cu coating on the surface of silicon carbide. The results shown that, the surface of silicon carbide particle which treated by alkaline wash was cleaner and more rough than that only treated by high-temperture oxidation, moreover, the specific surface of the particle was increased, which resulted in a compact layer of Cu coating. for the same silicon carbide particles, the effect of the Cu coating prepared by decomposition reaction method was better than that by reduction reaction method.

scholarly journals Study Cases (web)

2020 ◽  
pp. 57
Author(s):  
Eugenia Karamouzi ◽  
Eleni Tsironi ◽  
Panopoulos Panagiotis
Keyword(s):  
Business Model ◽  
Nutritional Value ◽  
Local Food ◽  
Osmotic Dehydration ◽  
Research Process ◽  
Precision Farming ◽  
Novel Processing ◽  
Main Activity ◽  
Processing Techniques

REZOS BRANDS is a food focused SME, with expertise in superfoods. The company is established in Patras, back in 1983, with main activity the distribution and development of national sales networks of imported and local food & beverages products, operating in the Greek market. Over the years REZOS BRANDS has extended its operations to all activities of the vertical business model: from the farm to the fork, which includes cultivation, harvesting, research, process, packaging, warehouse storing, marketing, distribution. Having own multifunctional farm, the super foods are cultivated and grown up with the principles of sustainable precision farming in order to develop, monitoring & analysing high nutritional value crops. The crops have been processed with novel processing techniques, such as osmotic dehydration.

scholarly journals Pengaruh Suhu Sintering Terhadap Sintesis Silicon Carbide (SiC) Berbahan Dasar Abu Sekam Padi dan Grafit Pensil 2B

2015 ◽  
Vol 5 (01) ◽  
pp. 31
Author(s):  
Resky Irfanita ◽  
Asnaeni Ansar ◽  
Ayu Hardianti Pratiwi ◽  
Jasruddin J ◽  
Subaer S
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silicon Carbide ◽  
Rice Husk Ash ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Scanning Electron

The objective of this study is to investigate the effect of sintering temperature on the synthesis of SiC produced from rice husk ash (RHA) and 2B graphite pencils. The SiC was synthesized by using solid state reaction method sintered at temperatures of 750°C, 1000°C and 1200°C for 26 hours, 11.5 hours and 11.5 hours, respectively. The quantity and crystallinity level of SiC phase were measured by means of Rigaku MiniFlexII X-Ray Diffraction (XRD). The microstructure of SiC was examined by using Tescan Vega3SB Scanning Electron Microscopy (SEM). The XRD results showed that the concentration (wt%) of SiC phase increases with the increasing of sintering temperature. SEM results showed that the crystallinity level of SiC crystal is improving as the sintering temperature increases

scholarly journals Effect of Cell Density on the Removal of Microcystis by Coagulation

2020 ◽  
Vol 42 (6) ◽  
pp. 319-326
Author(s):  
Joo Eun Han ◽  
Wontae Lee
Keyword(s):  
Surface Water ◽  
Chlorophyll A ◽  
Cell Density ◽  
Target Cell ◽  
Removal Rate ◽  
Nakdong River ◽  
Removal Rates ◽  
Cell Densities

Objectives:This study evaluated the removal of <i>Microcystis</i> by coagulation in raw waters with three different cell densities.Methods:Raw waters were prepared at three different cell densities (target cell densities of 10,000, 100,000, and 1,000,000 cell/mL; actual cell densities of 9,950, 102,000, and 991,000 cell/mL) by adding <i>Microcystis</i> into surface water from Nakdong river. Jar-tests were conducted with PACL, alum, illite, and loess at dosages of 0-150 mg/L.Results and Discussion:Regardless of coagulant types, the removal rates of <i>Microcystis</i> increased as the coagulant dosages increased. PACl and alum exhibited higher removal rates than illite and loess; PACl was the best coagulant to remove <i>Microcystis</i>. Removal of chlorophyll-a was highest when PACl added at 20.4 mg/L, and no significant increase in removal rate was observed with higher dosages of PACl. However, removal rates of chlorophyll-a by illite and loess gradually increased as the dosages increased.Conclusions:With the coagulants tested in this study, removal rates of <i>Microcystis</i> increased as the coagulant dosages increased. Removal rates of <i>Microcystis</i> increased as the cell densities increased probably because <i>Microcystis</i> acted as particles which could enhance the coagulation efficiency.

scholarly journals Cell density-dependent stimulation of PAI-1 and hyaluronan synthesis by TGF-β in orbital fibroblasts

2016 ◽  
Vol 229 (2) ◽  
pp. 187-196 ◽  
Author(s):  
Erika Galgoczi ◽  
Florence Jeney ◽  
Annamaria Gazdag ◽  
Annamaria Erdei ◽  
Monika Katko ◽  
...  
Keyword(s):  
Cell Density ◽  
Inverse Correlation ◽  
Fold Increase ◽  
Dermal Fibroblasts ◽  
Negative Regulator ◽  
Dependent Manner ◽  
Density Dependent ◽  
Cell Densities ◽  
Orbital Fibroblasts ◽  
Pai 1

During the course of Graves’ orbitopathy (GO), orbital fibroblasts are exposed to factors that lead to proliferation and extracellular matrix (ECM) overproduction. Increased levels of tissue plasminogen activator inhibitor type 1 (PAI-1 (SERPINE1)) might promote the accumulation of ECM components. PAI-1 expression is regulated by cell density and various cytokines and growth factors including transforming growth factorβ(TGF-β). We examined the effects of increasing cell densities and TGF-β on orbital fibroblasts obtained from GO patients and controls. Responses were evaluated by the measurement of proliferation, PAI-1 expression, and ECM production. There was an inverse correlation between cell density and the per cell production of PAI-1. GO orbital, normal orbital, and dermal fibroblasts behaved similarly in this respect. Proliferation rate also declined with increasing cell densities. Hyaluronan (HA) production was constant throughout the cell densities tested in all cell lines. In both GO and normal orbital fibroblasts, but not in dermal fibroblasts, TGF-β stimulated PAI-1 production in a cell density-dependent manner, reaching up to a five-fold increase above baseline. This has been accompanied by increased HA secretion and pericellular HA levels at high cell densities. Increasing cell density is a negative regulator of proliferation and PAI-1 secretion both in normal and GO orbital fibroblasts; these negative regulatory effects are partially reversed in the presence of TGF-β. Cell density-dependent regulation of PAI-1 expression in the orbit, together with the local cytokine environment, may have a regulatory role in the turnover of the orbital ECM and may contribute to the expansion of orbital soft tissue in GO.

Novel processing techniques and spinach juice: Quality and safety improvements

2020 ◽  
Vol 85 (4) ◽  
pp. 1018-1026 ◽  
Author(s):  
Muhammad Faisal Manzoor ◽  
Zahoor Ahmed ◽  
Nazir Ahmad ◽  
Rana Muhammad Aadil ◽  
Abdul Rahaman ◽  
...  
Keyword(s):  
Juice Quality ◽  
Quality And Safety ◽  
Novel Processing ◽  
Processing Techniques
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