Gelcasting of Fused Quartz Crucible with Large Scale

2012 ◽  
Vol 512-515 ◽  
pp. 399-402 ◽  
Author(s):  
Cheng Gong Sun ◽  
Jin Ye Niu ◽  
Hai Jian Li ◽  
Qiang Lian ◽  
Hai Jie Yu ◽  
...  
Keyword(s):  
Coupling Agent ◽  
Large Scale ◽  
Bending Strength ◽  
Volume Density ◽  
Curing Temperature ◽  
Quartz Crucible ◽  
Ph Values ◽  
Fused Quartz ◽  
Solids Content

Fused Quartz crucible with large scale was formed by gelcasting processing in this paper. Effects of dispersant, pH values and particle grading on solids content of slurries were discussed to increase the volume density of the green compacts and decrease the shrinkage and deformation during sintering. Effects of acrylamide content and the ratio of acrylamide to coupling agent on bending strength of the green compacts were investigated. Effects of the amount of initiator and curing temperature on the gelcasting processing were studied as well. The green compacts with solids content of 80% was obtained when the addition ratio of dispersant to Quartz powders was 0.3wt %, the ratio of Quartz powders in D50 of 1.9μm and 7.6μm was adjusted to 3:7, the addition ratio of acrylamide to Quartz powders was 1.0wt % and the ratio of acrylamide to coupling agent was 16:1. The bending strength of the sinterred produts was found to be 76.0MPa with volume density of 1.94 g/cm2. Fused Quartz crucible prepared under conditions mentioned above was 800mm in length, 800mm in width and 400mm in height.

scholarly journals Outdoor Large-Scale Cultivation of the Acidophilic Microalga Coccomyxa onubensis in a Vertical Close Photobioreactor for Lutein Production

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 324 ◽  
Author(s):  
Juan-Luis Fuentes ◽  
Zaida Montero ◽  
María Cuaresma ◽  
Mari-Carmen Ruiz-Domínguez ◽  
Benito Mogedas ◽  
...  
Keyword(s):  
Biomass Production ◽  
Large Scale ◽  
Culture Conditions ◽  
High Concentration ◽  
Ph Values ◽  
Lutein Content ◽  
Acidic Waters ◽  
Large Scale Cultivation ◽  
Rate Limiting ◽  
Lutein Production

The large-scale biomass production is an essential step in the biotechnological applications of microalgae. Coccomyxa onubensis is an acidophilic microalga isolated from the highly acidic waters of Río Tinto (province of Huelva, Spain) and has been shown to accumulate a high concentration of lutein (9.7 mg g−1dw), a valuable antioxidant, when grown at laboratory-scale. A productivity of 0.14 g L−1 d−1 was obtained by growing the microalga under outdoor conditions in an 800 L tubular photobioreactor. The results show a stable biomass production for at least one month and with a lutein content of 10 mg g−1dw, at pH values in the range 2.5–3.0 and temperature in the range 10–25 °C. Culture density, temperature, and CO2 availability in highly acidic medium are rate-limiting conditions for the microalgal growth. These aspects are discussed in this paper in order to improve the outdoor culture conditions for competitive applications of C. onubensis.

Further Evaporation and Final Treatment of Process-Water Concentrates

1999 ◽  
Vol 40 (11-12) ◽  
pp. 25-32
Author(s):  
Paterson McKeough ◽  
Leena Fagernäs
Keyword(s):  
Large Scale ◽  
Treatment Process ◽  
Treatment Options ◽  
Paper Mill ◽  
Pilot Scale ◽  
Forced Circulation ◽  
Final Treatment ◽  
Solids Content ◽  
Combustion Processes ◽  
Future Work

The study is part of a longer-term effort aimed at developing a separate treatment process for evaporation-concentrates of paper-mill process waters. This article deals with research on the two key processing steps; namely, the further evaporation and the final treatment of the concentrates. In laboratory experiments, various feed waters, including several different TMP filtrates, were evaporated to high dry-solids contents. The condensates recovered in most experiments contained relatively small amounts of organic matter. The extent of vapourisation of organic acids, relative to water, increased somewhat with increase in dry-solids content. Two TMP concentrates from large-scale evaporation plants were further concentrated in a pilot-scale forced-circulation evaporator. Viscosity was the factor limiting the extent of concentration. Using an evaporation temperature of about 80°C, the maximum dry-solids contents achieved with the two different concentrates were about 45 wt% and about 60 wt%, respectively. Fouling of heat-transfer surfaces was observed with both concentrates. A techno-economic evaluation of final-treatment options for alkali-rich concentrates is under way. According to intermediate results, molten-phase combustion processes would not require support fuel once the dry-solids content of TMP concentrate exceeds about 50 wt%. The aim of future work is to optimise the overall treatment process.

scholarly journals THE INFLUENCE OF PROCESS CONDITIONS ON GROUND COAL SLAG AND BLAST FURNACE SLAG BASED GEOPOLYMER PROPERTIES

2020 ◽  
Vol 35 (4) ◽  
pp. 15-20
Author(s):  
Quyen V. Trinh ◽  
Gábor Mucsi ◽  
Thai V. Dang ◽  
Ly P. Le ◽  
Van H. Bui ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Particle Density ◽  
Curing Temperature ◽  
Process Conditions ◽  
Ph Values ◽  
Specimen Density ◽  
Coal Slag ◽  
Furnace Slag

In this study, the material characterization of Vietnamese ground coal slag and ground granulated blast furnace slag (GGBFS), such as particle size distribution, chemical composition, bulk density and particle density are shown. The geopolymer specimens were prepared by mixing an 80 m/m% mass of solid materials (ground coal slag and GGBFS in a different ratio) with 20 m/m % of a 10M NaOH alkaline activator. A systematic experimental series was carried out in order to optimize the preparation process. In that series, the heat curing temperature was 60°C for 6 hours, and then selected specimens were heat treated at a high temperature (1000 °C) for 1 hour. After 7 days of ageing, the physical properties of the geopolymer (compressive strength, specimen density) were measured. Also, after 180 days of ageing, the pH values of water in the geopolymer leaching preparation were determined. The results show that the geopolymer can be used for refractory applications due to its good heat resistance properties. However, geopolymers that were heated at 1000 °C had lower compressive strength, specimen density and pH values of water containing the geopolymer than those that were cured at 60 °C.

scholarly journals Effects of the Particle Size of BaTiO3 Fillers on Fabrication and Dielectric Properties of BaTiO3/Polymer/Al Films for Capacitor Energy-Storage Application

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 439 ◽  
Author(s):  
Lulu Gu ◽  
Tao Li ◽  
Yongjun Xu ◽  
Chenghua Sun ◽  
Zhenyu Yang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Dielectric Properties ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Large Scale ◽  
Composite Films ◽  
Major Influence ◽  
Energy Storage Application ◽  
Dielectric Performance ◽  
Silane Coupling

BaTiO3/polymer/Al (BPA) composite films for energy storage were fabricated by way of a roll coating and thermal curing process. The coating slurry consisted of silicon-containing heat-resistant resin (CYN-01) and BaTiO3 particles with various particle sizes obtained from commercial BaTiO3 powders processed at different durations of wet sand grinding in the presence of silane coupling agent (KH550), which not only improves the dielectric performance of the BPA films but also facilitates its production in a large scale. The major influence factors, such as the ratio between BaTiO3 and resin and the size of BaTiO3 particles, were investigated and their related mechanisms were discussed. The results show that modifying BaTiO3 particles (D90 = 0.83 μm) with the silane coupling agent of KH550 enhances the dielectric properties of the BPA films. The typical BPA films obtained exhibit a high dielectric constant of 32, a high break strength of 20.8 V/μm and a low dielectric loss of 0.014. The present work provides a simple and convenient way to prepare high-quality ceramic/polymer composite films for energy-storage application in a large scale.

Effect of Si3N4-Y2O3 Compound Additive on Crystallization and Sintering of Fused Quartz Ceramic Materials

2011 ◽  
Vol 335-336 ◽  
pp. 713-716
Author(s):  
Shu Long Liu ◽  
Zhi Fa Wang ◽  
Jing Long Bu ◽  
Shu Bin Shen ◽  
Li Xue Yu
Keyword(s):  
Thermal Expansion ◽  
Bending Strength ◽  
Ceramic Materials ◽  
Quartz Ceramic ◽  
Apparent Porosity ◽  
Raw Material ◽  
Expansion Rate ◽  
Obvious Effect ◽  
Fused Quartz

Fused quartz granules (d50=19 μm) were used as raw material, and Si3N4-Y2O3 (1:1, in mass) was used as additive with dosages of 1%, 2% and 3% (in mass). Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h. The effect of Si3N4-Y2O3 on crystallization and sintering of the fused quartz ceramic materials were researched by measurements of apparent porosity, bending strength and thermal expansion rate (RT~1200 °C), and by the analyses of XRD and SEM. The results showed that the samples sintered at each temperature with 3% Si3N4-Y2O3 had the lowest apparent porosity, the highest bending strength and more compact microstructure. This indicated that 3% Si3N4-Y2O3 was conducive to sintering of fused quartz ceramic materials. The results of XRD and thermal expansion rate showed that addition of 3% Si3N4-Y2O3 compound had obvious effect on inhibiting crystallization of the samples sintered at various temperatures. It can be deduced that the Si3N4-Y2O3 compound plays the best role in inhibiting crystallization and facilitating sintering of fused quartz ceramic materials.

Combined treatment of green pitch pine wood by heat and superheated steam and the effects on physical properties of the products

Holzforschung ◽  
2014 ◽  
Vol 68 (3) ◽  
pp. 327-335 ◽  
Author(s):  
Yonggun Park ◽  
Chang-Deuk Eom ◽  
Yeonjung Han ◽  
Jun-Ho Park ◽  
Yoon-Seong Chang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Physical Properties ◽  
Large Scale ◽  
Superheated Steam ◽  
Bending Strength ◽  
Combined Treatment ◽  
Decay Resistance ◽  
Green Wood ◽  
Heat Treated ◽  
Pitch Pine

Abstract Pitch pine (P. rigida) wood was treated with superheated steam (SHS) and the subsequent effects due to drying and heat treatment (HT) were observed. The following treatment parameters were tested: 180°C air HT, 220°C air HT, 0.1 MPa–180°C SHS HT, 0.1 MPa–220°C SHS HT, 0.5 MPa–180°C SHS HT, and 0.5 MPa–220°C SHS HT. No drying checks were observed in the specimens (500×150×50 mm3) treated at 0.5 MPa–220°C SHS and with these treatment parameters, equilibrium moisture content (EMC) was the lowest. Low EMC has an effect on physical properties such as shrinkage, compressive strength parallel to the grain, bending strength, hardness, and decay resistance. Based on the results, it is expected that the green wood in a large scale is possible to be simultaneously dried and heat-treated without occurrence of checks by the SHS HT process.

Fracture behavior of fused quartz with laser-induced internal flaws

1994 ◽  
Vol 9 (7) ◽  
pp. 1780-1788 ◽  
Author(s):  
Y.Z. Li ◽  
M.P. Harmer ◽  
Y.T. Chou
Keyword(s):  
Fracture Behavior ◽  
Room Temperature ◽  
Bending Strength ◽  
Laser Pulse Energy ◽  
Laser Light ◽  
Threshold Value ◽  
Flaw Size ◽  
Demarcation Line ◽  
Four Point Bending ◽  
Fused Quartz

Pulsed-laser light was used to generate internal flaws in fused quartz. The size of the flaw produced was proportional to the amount of laser pulse energy above a threshold value of 2.5 mJ. Specimens of different flaw sizes were tested at room temperature under four-point bending. The bending strength decreased as the flaw size increased, and a Griffith relationship was established between the lateral flaw size and the critical stress at the flaw tip. Characteristic demarcation lines were observed on the fracture surfaces of specimens with a flaw size greater than 0.25 mm. It is suggested that the formation of the demarcation line is caused by a discontinuous change of stress intensity in the dynamic process of the crack propagation.

Influence of Nano-Y2O3 on Crystallization Behavior and Sintering Performance of Fused Quartz Ceramic Materials

2011 ◽  
Vol 284-286 ◽  
pp. 1366-1369
Author(s):  
Yue Jun Chen ◽  
Zhi Fa Wang ◽  
Li Xue Yu ◽  
Jing Long Bu ◽  
Rong Lin Wang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Bending Strength ◽  
Ceramic Materials ◽  
Quartz Ceramic ◽  
Apparent Porosity ◽  
Raw Material ◽  
Expansion Rate ◽  
Peak Intensity ◽  
Fused Quartz ◽  
Crystallization Inhibitor

Fused quartz granule (d50=0.019 mm) was used as raw material, nano-Y2O3 (size<0.08 μm) was used as additive with dosages of 1% (in mass, similarly hereinafter), 2% and 3%. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h. Properties of samples were researched by measurements of apparent porosity, bending strength and thermal expansion rate, and analyzed by XRD and SEM. The results showed that additive nano-Y2O3 had good inhibiting effect on crystallization of fused quartz sintered at various temperatures, sample added 2% nano-Y2O3 had least thermal expansion rate, diffraction peak intensity and apparent porosity, and it had higher bending strength and more compact microstructure, especially sample sintered at 1350 °C. It can be deduced that 2% nano-Y2O3 plays the excellent role as the crystallization inhibitor and sintering assistant to fused quartz materials sintered at various temperatures.

Preparation and Characterization of Fused Silica Micro-Powders and Ceramics

2011 ◽  
Vol 412 ◽  
pp. 129-132 ◽  
Author(s):  
Jin Ye Niu ◽  
Zhi Wei Chen ◽  
Liu Feng ◽  
Zheng Min Li ◽  
Min Tan
Keyword(s):  
Particle Size ◽  
Thermal Expansion ◽  
Lactic Acid ◽  
Milling Time ◽  
Bending Strength ◽  
Slip Casting ◽  
Volume Density ◽  
Fused Silica ◽  
Lactic Acid Content

Fused silica micro-powders with D50of 1.8μm were firstly prepared by ball milling. Effects of milling time on particle size distribution and microstructures of the powders were discussed. Then, the green compacts with volume density of 1.86g/cm3was obtained by slip casting with lactic acid as dispersant. Effects of lactic acid content on apparent viscosity of the slurry, thickness and density of the green compacts were investigated. Finally, fused silica ceramics with thermal expansion coefficient of 0.56∙10-6/°C, bending strength of 64MPa and volume density of 1.94g/cm3were prepared.

ELID Grinding Properties of High-Strength Reaction-Sintered SiC

2005 ◽  
Vol 291-292 ◽  
pp. 121-126 ◽  
Author(s):  
Y. Dai ◽  
Hitoshi Ohmori ◽  
Wei Min Lin ◽  
H. Eto ◽  
N. Ebizuka ◽  
...  
Keyword(s):  
Large Scale ◽  
Bending Strength ◽  
Ground Surface ◽  
High Strength ◽  
Scale Space ◽  
High Quality ◽  
Elid Grinding ◽  
Sic Ceramics ◽  
Cup Wheel ◽  
Sintered Silicon

The high-strength reaction-sintered silicon carbide (RS-SiC) developed by TOSHIBA is one of the most excellent materials for large-scale space-borne optics. The bending strength of the high-strength RS-SiC is two times higher than other SiC ceramics. The purpose of this study is to investigate the ELID grinding properties of the high strength RS-SiC. Two types of metal bond diamond wheels (cup type and straight type) were used to grinding tests. The ground surface properties, such as roughness, subsurface damage and micro-step were made clear by measurement or observation. It was confirmed that, both the surface roughness and the depth of micro-step produced by cup-wheel were lower than those produced by straight-wheel. When a #20000 grit sized cup-wheel was used, a considerably high quality mirror surface (Ra<0.8nm) can be achived.

Sign in / Sign up

Export Citation Format

Share Document