Humidity effects in Fe16N2 fine powder preparation by low-temperature nitridation

2010 ◽  
Vol 183 (9) ◽  
pp. 2236-2241 ◽  
Author(s):  
Kohetsu Yamanaka ◽  
Yuki Onuma ◽  
Shohei Yamashita ◽  
Yuji Masubuchi ◽  
Takashi Takeda ◽  
...  
Keyword(s):  
Low Temperature ◽  
Fine Powder ◽  
Powder Preparation ◽  
Humidity Effects

scholarly journals Short Communication: Mechanism and Prevention of Irreversible Trapping of Atmospheric He During Mineral Crushing

2022 ◽  
Author(s):  
Stephen Ellis Cox ◽  
Hayden Bryce Dutcher Miller ◽  
Florian Hofmann ◽  
Kenneth Anthony Farley
Keyword(s):  
Low Temperature ◽  
Vacuum Chamber ◽  
Short Communication ◽  
Noble Gases ◽  
Noble Gas ◽  
Fine Powder ◽  
Analytical Techniques ◽  
Inert Atmosphere ◽  
Laboratory Equipment ◽  
Fine Grained

Abstract. A pervasive challenge in noble gas geochemistry is to ensure that analytical techniques do not modify the composition of the noble gases in the samples. Noble gases are present in the atmosphere and are used in a number of manufacturing procedures and by laboratory equipment. Of particular concern is the introduction of atmospheric or laboratory noble gases to samples during preparation before samples are placed in a vacuum chamber for analysis. Recent work has shown the potential for contamination of crushed samples with air-derived He that is not released by placing the samples under vacuum at low temperature. Using pure He gas as a tracer, we show that the act of crushing samples to a fine powder itself can introduce He contamination, but that this is easily avoided by crushing under liquid or in an inert atmosphere. Because the He is trapped during crushing, the same concern does not extend to samples that are naturally fine-grained when collected. The degree of He contamination even from crushing samples to sizes smaller than typically used for geochronology is insignificant for samples at least 1 Ma and with more than 1 ppm U when the guidelines outlined here are followed.

Influence of Si3N4 Adding on the Performance of Al-Al2O3 Composite

2014 ◽  
Vol 633 ◽  
pp. 53-56
Author(s):  
Chuan Jing Li ◽  
Yong Li ◽  
Hai Xia Qin ◽  
Jia Lin Sun ◽  
Jun Hong Chen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Phenolic Resin ◽  
Raw Materials ◽  
Fine Powder ◽  
Nitrogen Atmosphere ◽  
Comprehensive Properties ◽  
Plastic Phase

Al-Si3N4-Al2O3composite was prepared using tabular corundum, white fused corundum,α-Al2O3fine powder and Si3N4fine powder as raw materials and phenolic resin as low temperature binder under nitrogen atmosphere at 1 300 °C for 8 h. The results show that the main reinforced phase of Al-Al2O3is Al4O4C in Al-Al2O3specimens without Si3N4fine powder adding,the main reinforced phase of Al-Si3N4-Al2O3is SIALON while small quantity of Al,Si plastic phase presents in Si3N4adding Al-Al2O3specimens. Si5AlON7(Z=1) is formed in Al-Si3N4-Al2O3specimens at low temperature (1 300 °C), which presents good comprehensive properties.

A kinetic study on the low temperature oxidation of CO over Ag-contaminated Au fine powder

2009 ◽  
Vol 262 (2) ◽  
pp. 280-286 ◽  
Author(s):  
Yasuo Iizuka ◽  
Tomonobu Miyamae ◽  
Takumi Miura ◽  
Mitsutaka Okumura ◽  
Masakazu Daté ◽  
...  
Keyword(s):  
Low Temperature ◽  
Kinetic Study ◽  
Fine Powder ◽  
Oxidation Of Co ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation

scholarly journals Sifat Fisik Serbuk Effervescent Ramuan Jamu Antihipertensi

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Titik Lestari
Keyword(s):  
Herbal Medicine ◽  
Urban Areas ◽  
Age Groups ◽  
Fine Powder ◽  
Centella Asiatica ◽  
Quality Standards ◽  
Powder Preparation ◽  
Self Medication ◽  
Physical Test ◽  
Dispersion Test

Background: Physical Test, Effervescent Powder, Antihypertensive Herbal. Data from Basic Health Research reports that the prevalence of hypertension in Indonesia in the population aged> 18 years is 29.8% and shows that the population of Indonesia which consumes 95.60% of herbal medicine has experienced benefits in all age groups and economic status, both in rural and urban areas but its utilization so far is still limited to self-medication and has not been done in health facilities. The scientific formula for herbal medicine for antihypertension includes Apium graveolans, Centella asiatica, Orthosiphon aristatus, Curcuma domestica, Phylantus niruri, Curcuma xanthoriza and has received a certificate from the Saintification National Herbal Medicine Commission and has been proven to be safe and efficacious. The observation authors of the use of antihypertensive herbs so far in the form of decoction preparations, it is necessary to make preparations that are practical and easy to consume and are expected with different dosage forms still have the same efficacy as lowering blood pressure, one of them in effervescent powder preparation and the need physical test for powder to find out quality standards. The aim of the study was to determine the results of the physical test of effervescent powder preparations. Method: The research method is descriptive with the research sample being effervescent powder. Results: The results showed that the results of the physical test of effervescent powder of antihypertensive herbs consisting of pH was 5.1, flow velocity was 6.56, stationary angle 21°, dispersion test was 3 minute 11 second . The moisture content of effervescent powder according to the standard is 1.5% (standard less than 5%), while the organoleptic results of effervescent powder of antihypertensive herbs showed results in fine powder, light brown color, sour taste, distinctive smell of antihypertensive herbal ingredients and homogeneous powder. Conclusion: The conclusion showed that the results of the physical test of effervescent powder was in accordance with quality standards.

Electron radiation damage of natural zeolites at room and low temperature

1990 ◽  
Vol 48 (4) ◽  
pp. 808-809
Author(s):  
Yasuhiro Yokota ◽  
Hatsujiro Hashimoto ◽  
Terutoshi Yamaguchi
Keyword(s):  
Low Temperature ◽  
Electron Energy ◽  
Room Temperature ◽  
Electron Beam Irradiation ◽  
Fine Powder ◽  
Amorphous Region ◽  
Lattice Images ◽  
Temperature Electron ◽  
Electron Microscopes ◽  
Electron Energy Loss

Zeolites are easily changed to amorphous under electron beam irradiation. Bando reported that this phenomena take place at low temperature with 1/20 dose of room temperature. In the present work this phenomena was investigated using two kinds of specimens, by changing temperature, electron energy (100 kV-350 kV) and also by applying an electron energy loss spectrometer.Mesolite is from Yaizu, Sizuoka Prefecture and Thomsonite is from Nishijima, Yamanasi Pref. , Japan. The specimen were ground to fine powder and dispersed on a microgrid. A Faraday gage which was installed in the observing chamber of the microscope was used for measure the dose rate. Decomposition was determined by measuring the current of a diffracted spot by the Faraday gage. Observation at low temperature was carried out using low temperature specimen holders fabricated to 200 kV and 400 kV electron microscopes.Fig. 1 (a), (b) are high resolution lattice images of Mesolite by 200 kV TEM operated in room temperature, (b) was taken 20 second after the same part of (a). The thickness of amorphous region in (a) is 8 nm, in (b) the amorphous region increased to 30 nm.

1,4-Bis(p-pentazolylphenyl)butan, 1-p-Azidophenyl-4-p-pentazolylphenyl- butan und 1,4-Bis(p-azidophenyl)butan / 1,4-Bis(p-pentazolylphenyl)butane, 1-p-Azidophenyl-4-p-pentazolylphenyl-butane and 1,4-Bis(p-azidophenyl)butane

2004 ◽  
Vol 59 (6) ◽  
pp. 716-720 ◽  
Author(s):  
Frank Biesemeier ◽  
Klaus Harms ◽  
Ulrich Müller
Keyword(s):  
Low Temperature ◽  
Sodium Azide ◽  
Rate Constants ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Fine Powder ◽  
Space Group ◽  
H Nmr ◽  
Diazonium Ions ◽  
C Nmr

1,4-Bis(p-pentazolylphenyl)butane (1), 1-p-azidophenyl-4-p-pentazolylphenyl-butane (2) and 1,4-bis(p-azidophenyl)butane (3) were obtained by the reaction of 1,4-diphenylbutane-4’,4”- bis(diazonium) ions with sodium azide in methanol at −50 °C. In the 1H and 13C NMR spectra the three compounds can be distinguished unequivocally. At −50 °C a mixture with a composition 1:2:3 of 10:30:60 was obtained. By recrystallization first from dichloromethane/methanol and then from dichloromethane/petroleum ether the pentazole components were enriched to a composition ratio of 21:62:17. The rate constants of the decompositions 1→2 and 2→3 at 0 °C were determined from the variation of the 1H NMR intensities. At room temperature all of the material is converted to 3. 3 crystallizes in two monoclinic modifications. At −70 °C a modification 3-LT having space group P21/c (a = 950.8, b = 1192.6, c = 701.3 pm, β = 92.55°, Z = 2; R = 0.075) was obtained. The modification crystallizing at room temperature (3-HT) has space group I2/a (a = 1514.5, b = 498.1, c = 2027.9 pm, β = 92.73°, Z = 4; R = 0.040). Whereas both modifications consist of nearly identical molecules, their packings are quite different. When the low temperature modification is warmed to room temperature, its crystals jump like flees and are disrupted to a fine powder.

Super Fine Powderization of Korean Ginseng Using Low Temperature Turbo Mill

2006 ◽  
Vol 326-328 ◽  
pp. 445-448 ◽  
Author(s):  
Beom Goo Lee ◽  
Yeon Ho Jeong ◽  
Dong Ha Cho ◽  
Kang Yol Lee ◽  
Wie Soo Kang
Keyword(s):  
Particle Size ◽  
Low Temperature ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Diameter ◽  
Fine Powder ◽  
Narrow Particle Size Distribution ◽  
Volume Distribution ◽  
The Mean ◽  
Korean Ginseng

It is investigated whether ginseng can be milled into super fine powder below 50μm, changing the circumferential velocity of impeller of a turbo mill(100, 110 and 120m/s). The mean particle size is 113.3μm in control but is decreased abruptly into 11.9μm at 120m/s. The largest particle diameter at 97% of volume distribution is reduced into below 32μm at 120m/s from below 725μm at control. The particle size distribution between d(0.1) and d(0.9) is 334μm at control, but is decreased into less than 26μm in all conditions after milling. It shows that ginseng can be milled into super fine powder by the turbo mill, which has the narrow particle size distribution.

Disintegration and fine powder preparation of Nb75Si25 via hydrogenation

1997 ◽  
Vol 260 (1-2) ◽  
pp. 153-156
Author(s):  
X.G. Li ◽  
A. Chiba ◽  
S. Takahashi
Keyword(s):  
Fine Powder ◽  
Powder Preparation
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