The effect of substituents on the stability of triply bonded galliumantimony molecules: a new target for synthesis

2017 ◽  
Vol 46 (6) ◽  
pp. 1848-1856 ◽  
Author(s):  
Jia-Syun Lu ◽  
Ming-Chung Yang ◽  
Ming-Der Su
Keyword(s):  
Computational Results ◽  
Effect Of Substituents ◽  
Stabilizing Effect ◽  
The Stability

The M06-2X, B3PW91 and B3LYP computational results show that, from the kinetic viewpoint, only bulkier substituents have a significant stabilizing effect on the triply bonded RGaSbR compounds.

The effect of substituents on triply bonded boronantimony molecules: a theoretical approach

2017 ◽  
Vol 19 (11) ◽  
pp. 8026-8033 ◽  
Author(s):  
Jia-Syun Lu ◽  
Ming-Chung Yang ◽  
Ming-Der Su
Keyword(s):  
Theoretical Approach ◽  
Theoretical Calculations ◽  
Decisive Role ◽  
Effect Of Substituents ◽  
Stabilizing Effect ◽  
Theoretical Evidence ◽  
The Stability

Theoretical calculations using the M06-2X, B3PW91 and B3LYP levels of theory demonstrate that the attached substituents (R) play a decisive role in determining the stability of triply bonded RBSbR molecules. Theoretical evidence shows that, from the kinetic viewpoint, only bulkier substituents have a significant stabilizing effect on the formation of the triply bonded RBSbR compounds.

scholarly journals Stabilizing effect of methylcellulose on the dispersion of multi-walled carbon nanotubes in cementitious composites

2020 ◽  
Vol 9 (1) ◽  
pp. 93-104
Author(s):  
Mingrui Du ◽  
Yuan Gao ◽  
Guansheng Han ◽  
Luan Li ◽  
Hongwen Jing
Keyword(s):  
Carbon Nanotubes ◽  
Pore Solution ◽  
Cementitious Materials ◽  
High Ionic Strength ◽  
Cementitious Composites ◽  
Uniform Distributions ◽  
Stabilizing Effect ◽  
Multi Walled Carbon Nanotubes ◽  
The Stability ◽  
Walled Carbon Nanotubes

AbstractMulti-walled carbon nanotubes (MWCNTs) have been added in the plain cementitious materials to manufacture composites with the higher mechanical properties and smart behavior. The uniform distributions of MWCNTs is critical to obtain the desired enhancing effect, which, however, is challenged by the high ionic strength of the cement pore solution. Here, the effects of methylcellulose (MC) on stabilizing the dispersion of MWCNTs in the simulated cement pore solution and the viscosity of MWCNT suspensions werestudied. Further observations on the distributions of MWCNTs in the ternary cementitious composites were conducted. The results showed that MC forms a membranous envelope surrounding MWCNTs, which inhibits the adsorption of cations and maintains the steric repulsion between MWCNTs; thus, the stability of MWCNT dispersion in cement-based composites is improved. MC can also work as a viscosity adjuster that retards the Brownian mobility of MWCNTs, reducing their re-agglomerate within a period. MC with an addition ratio of 0.018 wt.% is suggested to achieve the optimum dispersion stabilizing effect. The findings here provide a way for stabilizing the other dispersed nano-additives in the cementitious composites.

scholarly journals Effect of Potato Pulp Pectic Polysaccharide on the Stability of Acidified Milk Drinks

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5632
Author(s):  
Weixuan Sun ◽  
Wenhan Yang ◽  
Yuxue Zheng ◽  
Huiling Zhang ◽  
Haitian Fang ◽  
...  
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Neutral Sugar ◽  
Lower Serum ◽  
Pectic Polysaccharide ◽  
Potato Pulp ◽  
Lower Viscosity ◽  
Stabilizing Effect ◽  
New Ideas ◽  
The Stability

In order to broaden the application of potato pulp pectic polysaccharide (PPP) in stabilizing acidified milk drinks (AMDs) and investigate the stabilizing effect and physical properties of AMDs prepared with PPP, a comparative study was made among PPP, commercial high methoxyl pectin (HMP) and low methoxyl pectin (LMP). The zeta potential, rheology, particle size and serum separation of AMDs were evaluated after preparing with PPP, HMP and LMP, respectively. Results indicated that PPP led to lower serum separation than LMP (14.65% for AMDs prepared with 0.5% PPP compared to 25.05% for AMDs prepared with 0.5% LMP), but still higher than HMP (9.09% for AMDs prepared with 0.5% HMP). However, narrower particle size distribution and lower viscosity of AMDs was achieved by PPP than by LMP and HMP. PPP can electrostatically adsorb on the surface of casein and its abundant neutral sugar side chains would provide steric hindrance to prevent casein flocculation in AMDs. Our results might provide some new ideas for the application of PPP in improving the stability of AMDs.

On the Stability of Two Superposed Viscous-Viscoelastic (Walters B′) Fluids

2006 ◽  
Vol 129 (1) ◽  
pp. 116-119 ◽  
Author(s):  
Pardeep Kumar ◽  
Roshan Lal
Keyword(s):  
Viscous Fluid ◽  
Viscoelastic Fluid ◽  
Kinematic Viscosity ◽  
Taylor Instability ◽  
Stable Configuration ◽  
Stabilizing Effect ◽  
Unstable Configuration ◽  
Rayleigh Taylor Instability ◽  
Newtonian Viscous Fluid ◽  
The Stability

The Rayleigh-Taylor instability of a Newtonian viscous fluid overlying Walters B′ viscoelastic fluid is considered. For the stable configuration, the system is found to be stable or unstable under certain conditions. However, the system is found to be unstable for the potentially unstable configuration. Further it is found numerically that kinematic viscosity has a destabilizing effect, whereas kinematic viscoelasticity has a stabilizing effect on the system.

Stability of Moving Combustion Fronts in Porous Media

1977 ◽  
Vol 17 (06) ◽  
pp. 423-430 ◽  
Author(s):  
Michael E. Armento ◽  
Clarence A. Miller
Keyword(s):  
Heat Transport ◽  
Thermal Processes ◽  
Condensation Rate ◽  
Sweep Efficiency ◽  
Stabilizing Effect ◽  
The Stability ◽  
Combustion Processes ◽  
Physical Phenomena ◽  
Front Stability ◽  
Moving Front

Abstract The stability of moving combustion fronts during underground combustion processes is analyzed. The behavior of small deformations in front configuration is studied using knew stability theory and relatively simple models of the combustion processes. In this way, the main physical phenomena that influence stability can be physical phenomena that influence stability can be distinguished clearly. For wet combustion processes, where both air and water are injected, front stability is affected, not only by the ratio of the mobilities of fluids flowing ahead of and behind the front, but also by heat transport near the front and by expansion accompanying vaporization of water at the front. Even more interesting is a "reverse mobility" effect predicted by the analysis. Under some conditions at relatively high air to water injection ratios, fluid flow, and the heat produced by combustion interact in such a way that normally "favorable" mobility ratios become unfavorable. That is, existence of a low mobility in the region of two-phase flow of air and water behind the front actually can promote front instability. For dry combustion the beat transport and reverse mobility effects on stability do not occur and the combustion fronts are typically neither highly stable nor highly unstable; That is, the effective mobility ratio is near unity. Introduction Thermal processes, such as underground combustion and steam drive, are prime candidates for supplementing primary recovery techniques in reservoirs containing highly viscous crude oils. Thermal methods also have been considered for tertiary recovery of lighter oils. Chemical flooding seems currently to be the preferred process, however, for this latter application. As is true for all recovery schemes, the over-all effectiveness of thermal processes depends on the injected fluids contacting a substantial portion of the reservoir, that is, on achieving good sweep efficiency. Of course, the amount of the reservoir swept depends on various factors, including reservoir heterogeneity and the pattern of wells. But studying the stability of moving displacement fronts in an idealized homogeneous porous medium provides useful information that, at a minimum, provides useful information that, at a minimum, gives a qualitative idea of what to expect in more complex situations. For example, if the front is unstable even in the simple case of a homogeneous medium, sweep efficiency is likely to be poor for any realistic reservoir conditions. It has been known for some years that a ratio between the mobilities () of displacing and displaced fluids that exceeds unity gives rise to a destabilizing influence on the moving front between them. Only recently has it been shown that other effects on front stability can be equally important during thermal recovery processes. Analysis of a simple situation with steam condensing and displacing water at a moving front indicated that the adverse mobility ratio because of low steam viscosity sometimes could be offset completely by two stabilizing effects. This conclusion is consistent with Baker's laboratory experiments on steam displacement that showed that moving condensation fronts are usually stable. One stabilizing effect at a condensation front is contraction accompanying condensation of a given mass of swam, a process which extracts mechanical energy from the flow. The other effect is heat transport in the water region, where the temperature varies from the saturation temperature at the front to ambient conditions far ahead of the front. The rate of front advance is controlled by the rate of condensation, high front velocities being associated with low condensation rates. The condensation rate, in turn, is limited by the rate at which the latent heat released at the front can be transported into the water. When the front is deformed as shown in Fig. 1 points such as P are exposed to a large amount of cool liquid so that the local heat flux increases. As a result, the local condensation rate increases at P, and the local front velocity decreases there, producing a stabilizing effect. This qualitative explanation of the transport effect on stability is an improvement over that given in the original paper. SPEJ P. 423

Dynamical Analysis of Prey Refuge in a Predator-Prey System with Rosenzweig Functional Response

2011 ◽  
Vol 271-273 ◽  
pp. 577-580
Author(s):  
Zhi Hui Ma ◽  
Shu Fan Wang ◽  
Wen Ting Wang
Keyword(s):  
Functional Response ◽  
Stability Property ◽  
Dynamical Analysis ◽  
Prey Refuge ◽  
Predator Prey ◽  
Prey System ◽  
Stabilizing Effect ◽  
The Stability ◽  
Prey Refuges

In this paper, we proposed a predator-prey system incorporating Rosenzweig functional response and prey refuges. We will consider the stability property of the equilibria. Our results show that refuges using by prey have stabilizing effect on the considered system.

scholarly journals Effect of Substituents on the Stability of Sulfur-Centered Radicals

2016 ◽  
Vol 120 (37) ◽  
pp. 7398-7403 ◽  
Author(s):  
Isa Degirmenci ◽  
Michelle L. Coote
Keyword(s):  
Effect Of Substituents ◽  
The Stability

scholarly journals A Study effect of Substituents X on Methylenecyclopentane and 1- Methylcyclopentene System

2018 ◽  
Vol 1 (1) ◽  
pp. 38-44
Author(s):  
Ghassab Al-Mazaideh
Keyword(s):  
Free Energy ◽  
Dft Calculations ◽  
Gibbs Free Energy ◽  
Free Energy Calculations ◽  
Relative Stabilities ◽  
Energy Calculations ◽  
Effect Of Substituents ◽  
Orbital Energies ◽  
The Stability ◽  
Homo Lumo

In this study, the geometry optimizations, orbital energies (HOMO-LUMO) and relative stabilities of methylene cyclopentane and 1-methylcyclopentene were investigated by DFT calculations. 1-methylcyclopentene was found to be more stable than methylene cyclopentane isomer with enthalpy value H=18.518 kJ/mol. Also, the effect of substituents X (F, OH, CH3, NH2, CN, NO2, CHO and CF3) also studied on the relative stabilities of these two tautomers. The results showed that the stability of both isomers is increased by all substitutes. Gibbs free energy calculations have been used to find the effect of substituents X on the system.

Influence of Upstream Turbulence on the Fluidelastic Instability of a Tube Bundle With Various Flexible Tubes

2002 ◽  
Author(s):  
M. Rottmann ◽  
K. Popp
Keyword(s):  
Heat Exchanger ◽  
Wind Tunnel ◽  
Tube Bundle ◽  
Stability Boundaries ◽  
Realistic Condition ◽  
Flexible Tube ◽  
Stabilizing Effect ◽  
The Stability ◽  
Flexible Tubes ◽  
Upstream Flow

The stability boundaries of a single flexible tube in one of the first rows of a tube bundle can be highly dependent on the turbulence characteristics of the upstream flow, cf. (Rottmann & Popp, 2001). For certain bundle geometries increased turbulence yields a stabilization of a flexible tube in the critical row. If this stabilization also occurs on the more realistic condition of a fully flexible bundle it could be a useful effect with respect to applications. The flow rate in a heat exchanger could be increased or existing stability problems could easily be solved by inserting turbulence grids at the inlet instead of changing the entire tube bundle. Therefore, wind tunnel tests have been carried out with various flexible tubes in the tube bundle. The vibrations in the tube bundle have been carefully observed and measured by means of accelerometers. These investigations still show a significant stabilizing effect of increased upstream turbulence.

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