Fluctuations of the Weight Indicated by a Microbalance in the Pressure Range Between 1 and 103 torr with the Sample at a Lower Temperature than the Beam

1970 ◽  
pp. 195-205 ◽  
Author(s):  
E. Robens ◽  
G. Sandstede ◽  
G. Walter ◽  
G. Wurzbacher
Keyword(s):  
Pressure Range ◽  
Lower Temperature

Study of 1-(2-Hydroxyethyle) 3-methylimidazolium Halide as Thermodynamic Inhibitors

2014 ◽  
Vol 625 ◽  
pp. 337-340 ◽  
Author(s):  
Omar Nashed ◽  
Khalik Mohamad Sabil ◽  
Bhajan Lal ◽  
Lukman Ismail ◽  
Azuraien Japper Jaafar
Keyword(s):  
High Pressure ◽  
Ionic Liquids ◽  
Gas Hydrates ◽  
Methane Hydrate ◽  
Pressure Range ◽  
Equilibrium Curve ◽  
Dissociation Temperature ◽  
Methane Gas Hydrates ◽  
Lower Temperature ◽  
Better Than

In this study, the performance of 1-(2-Hydroxyethyle) 3-methylimidazolium chloride [OH-EMIM][Cl] and 1-(2-Hydroxyethyle) 3-methylimidazolium bromide [OH-EMIM][Br] was investigated as thermodynamic gas hydrate inhibitors. The dissociation temperature was determined for methane gas hydrates using a high pressure micro deferential scanning calorimeter at a pressure range of 36-97 bar. Both ionic liquids (ILs) were studied at concentrations of 5, 10, 15, 20 and 25 wt% then their performance was compared with commercially available inhibitors. It was observed that both ILs shift the methane hydrate equilibrium curve to lower temperature and higher pressure; and the performance of [OH-EMIM][Cl] is better than [OH-EMIM][Br]. Nevertheless both of them were found to be less effective compared to methanol and mono ethylene glycol.

Silicon Tetrachloride Synthesis from Rice Hulls: Transmission and Scanning Electron Microscope Study

1972 ◽  
Vol 30 ◽  
pp. 236-237 ◽  
Author(s):  
Richard S. Thomas ◽  
Prabir K. Basu ◽  
Francis T. Jones
Keyword(s):  
Silicon Tetrachloride ◽  
Silica Sand ◽  
Mineral Matter ◽  
Chemical Heterogeneity ◽  
Scanning Electron Microscope Study ◽  
Rice Hulls ◽  
Hull Structure ◽  
Lower Temperature ◽  
Image Position ◽  
Disposal Problem

Silicon tetrachloride, used in industry for the production of highest purity silicon and silica, is customarily manufactured from silica-sand and charcoal.SiCl4 can also be made from rice hulls, which contain up to 20 percent silica and only traces of other mineral matter. Hulls, after carbonization, actually prove superior as a starting material since they react at lower temperature. This use of rice hulls may offer a new, profitable solution for a rice mill byproduct disposal problem.In studies of the reaction kinetics with carbonized hulls, conversion of SiO2 to SiCl4 was found to proceed within a few minutes to a constant, limited yield which depended reproducibly on the ambient temperature of the reactor. See Fig. 1. This suggested that physical or chemical heterogeneity of the silica in the hull structure might be involved.

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 565-576 ◽  
Author(s):  
YUCHENG PENG ◽  
DOUGLAS J. GARDNER
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Particle Morphology ◽  
Nanofibrillated Cellulose ◽  
Particle Sizes ◽  
Hydroxyl Number ◽  
Small Individual ◽  
Dispersion Component ◽  
Commercial Applications ◽  
Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

Formation of Nanocrystalline Silicon in Tin-Doped Amorphous Silicon Films

2020 ◽  
Vol 65 (3) ◽  
pp. 236
Author(s):  
R. M. Rudenko ◽  
O. O. Voitsihovska ◽  
V. V. Voitovych ◽  
M. M. Kras’ko ◽  
A. G. Kolosyuk ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Crystalline Silicon ◽  
Solid Phase ◽  
Nanocrystalline Silicon ◽  
Recrystallization Temperature ◽  
Nanocrystalline Phase ◽  
Silicon Phase ◽  
Silicon Nanocrystallites ◽  
Lower Temperature ◽  
Two Stages

The process of crystalline silicon phase formation in tin-doped amorphous silicon (a-SiSn) films has been studied. The inclusions of metallic tin are shown to play a key role in the crystallization of researched a-SiSn specimens with Sn contents of 1–10 at% at temperatures of 300–500 ∘C. The crystallization process can conditionally be divided into two stages. At the first stage, the formation of metallic tin inclusions occurs in the bulk of as-precipitated films owing to the diffusion of tin atoms in the amorphous silicon matrix. At the second stage, the formation of the nanocrystalline phase of silicon occurs as a result of the motion of silicon atoms from the amorphous phase to the crystalline one through the formed metallic tin inclusions. The presence of the latter ensures the formation of silicon crystallites at a much lower temperature than the solid-phase recrystallization temperature (about 750 ∘C). A possibility for a relation to exist between the sizes of growing silicon nanocrystallites and metallic tin inclusions favoring the formation of nanocrystallites has been analyzed.

Quality indicators of the spontaneous fermentation starters of cereals flour during the lower-temperature conservation process

2018 ◽  
Vol 6 (11) ◽  
pp. 116-122
Author(s):  
Larysa Mikhonik ◽  
◽  
Inna Getman ◽  
Natalia Bela ◽  
Halyna Bogdan ◽  
...  
Keyword(s):  
Quality Indicators ◽  
Spontaneous Fermentation ◽  
Lower Temperature ◽  
Fermentation Starters

The Binding and Viscometric Studies of Ni+2, Co+2 and Mn+2 Ions with Protein by Spectrometric and pH Metric Techniques

2019 ◽  
Vol 9 (2) ◽  
pp. 151-162
Author(s):  
Shveta Acharya ◽  
Arun Kumar Sharma
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Protein Molecule ◽  
Vital Role ◽  
Sufficient Evidence ◽  
Structural Requirement ◽  
Nickel Ions ◽  
Cobalt Ions ◽  
Lower Temperature ◽  
Specific Oxidation

Background: The metal ions play a vital role in a large number of widely differing biological processes. Some of these processes are quite specific in their metal ion requirements. In that only certain metal ions, in specific oxidation states, can full fill the necessary catalytic or structural requirement, while other processes are much less specific. Objective: In this paper we report the binding of Mn (II), Ni (II) and Co (II) with albumin are reported employing spectrophotometric and pH metric method. In order to distinguish between ionic and colloidal linking, the binding of metal by using pH metric and viscometric methods and the result are discussed in terms of electrovalent and coordinate bonding. Methods: The binding of Ni+2, Co+2 and Mn+2 ions have been studied with egg protein at different pH values and temperatures by the spectrometric technique. Results: The binding data were found to be pH and temperature dependent. The intrinsic association constants (k) and the number of binding sites (n) were calculated from Scatchard plots and found to be at the maximum at lower pH and at lower temperatures. Therefore, a lower temperature and lower pH offered more sites in the protein molecule for interaction with these metal ions. Statistical effects seem to be more significant at lower Ni+2, Co+2 and Mn+2 ions concentrations, while at higher concentrations electrostatic effects and heterogeneity of sites are more significant. Conclusion: The pH metric as well as viscometric data provided sufficient evidence about the linking of cobalt, nickel and manganese ions with the nitrogen groups of albumin. From the nature and height of curves in the three cases it may be concluded that nickel ions bound strongly while the cobalt ions bound weakly.

Mesoporous Silica Nanoparticles of Hydroxyurea: Potential

2020 ◽  
Vol 10 ◽  
Author(s):  
Kumar Nishchaya ◽  
Swatantra K.S. Kushwaha ◽  
Awani Kumar Rai
Keyword(s):  
Drug Release ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
Release Kinetics ◽  
Average Particle Size ◽  
Silica Nanoparticle ◽  
Average Particle ◽  
Independent Variables ◽  
Lower Temperature

Background: Present malignant cancer medicines has the advancement of magnetic nanoparticles as delivery carriers to magnetically accumulate anticancer medication in malignant growth tissue. Aim: In the present investigation, a silica nanoparticles (MSNs) stacked with hydroxyurea were combined and was optimized for dependent and independent variables. Method: In this study, microporous silica nanoparticle stacked with neoplastic medication had been prepared through emulsification followed with solvent evaporation method. Prepared MSNs were optimized for dependent and independent variables. Different formulations were prepared with varying ratio of polymer, lipid and surfactant which affects drug release and kinetics of drug release pattern. The obtained MSNs were identified by FTIR, SEM, drug entrapment, in-vitro drug release, drug release kinetics study, stability testing in order to investigate the nanoparticle characteristics. Results: The percentage drug entrapment of the drug for the formulations F1, F2, F3, was found to be 27.78%, 65.52% and 48.26%. The average particle size for F2 formulation was found to be 520 nm through SEM. The cumulative drug release for the formulations F1, F2, F3 was found to be 64.17%, 71.82% and 32.68%. The formulations were found to be stable which gives controlled drug delivery for 6 hours. Conclusion: From the stability studies data it can be culminated that formulations are most stable when stored at lower temperature or in refrigerator i.e. 5˚C ± 3˚C. It can be concluded that MSN’s loaded with hydroxyurea is a promising approach towards the management of cancer due to its sustained release and less side effects.

Effect of Irradiation of the Extraction Mixture with 30% TBP in ISOPAR-M on the Lower Temperature Limit of Flame Propagation

2020 ◽  
Vol 62 (6) ◽  
pp. 723-729
Author(s):  
A. V. Rodin ◽  
I. V. Skvortsov ◽  
E. V. Belova ◽  
K. N. Dvoeglazov ◽  
B. F. Myasoedov
Keyword(s):  
Flame Propagation ◽  
Temperature Limit ◽  
Lower Temperature Limit ◽  
Lower Temperature ◽  
Extraction Mixture

The deuterium interaction with tungsten and iridium in the UHV system

1985 ◽  
Vol 50 (12) ◽  
pp. 2656-2664
Author(s):  
Karel Kuchynka ◽  
Zlatko Knor
Keyword(s):  
Partial Pressure ◽  
Chemical Reactions ◽  
Pressure Range ◽  
Tungsten Filament ◽  
Different Temperatures ◽  
Pressure Changes

The behaviour of hydrogen, in its contact with the iridium and the tungsten filament kept at different temperatures, was studied in the pressure range 1.3 . 10-6 - 1.3 . 10-3 Pa, in a glass apparatus. The effects of adsorption, atomization, desorption, recombination of atoms and chemical reactions were investigated as a function of temperature of the filaments. The named individual processes were used for interpretation of the partial pressure changes in the apparatus. The significance of the above individual phenomena in the UHV experiments is pointed out in this paper.

Sign in / Sign up

Export Citation Format

Share Document