Influence of addition of exomodified carbon nanospheres on the structuration in ethanol motor fuels

2021 ◽  
pp. 62-68
Author(s):  
E.V. Polunkin ◽  
◽  
V.S. Pyliavskyi ◽  
O.O. Gaidai ◽  
S.L. Melnykova ◽  
...  
Keyword(s):  
Saturated Vapor ◽  
General Mechanism ◽  
Carbon Nanospheres ◽  
Ethanol Fuel ◽  
Photon Correlation ◽  
Operational Characteristics ◽  
Low Concentrations ◽  
Motor Fuels ◽  
Donor Acceptor ◽  
Individual Particles

The work is devoted to elucidation of a general mechanism of action of exomodified carbon nanospheres (CNOs – Brn nanoonions) on different physicochemical and chemmotological properties of ethanol motor fuels. The formation of supramolecular solvate groups in organic media is explained by the participation of different forces of intermolecular interaction, the main of which are polarization and orientation, as well as donor-acceptor forces of interaction of nanospheres with the environment. The concept of creation in an organic medium of solvation formations - domains, the size of which, determined by the method of photon correlation laser spectroscopy, varies from 21 to 1000 nm, depending on the chemical nature of the solvent - is proposed and substantiated. For ethanol, the size of such formations was ~ 400 nm, which significantly exceeds the size of individual particles of the additive. It is established that to improve the operational characteristics of ethanol fuel it is enough to introduce low concentrations (10-3 - 10-2 %, wt.) of synthesized brominated nanoparticles. It is shown that the change of the microheterogeneous structure of fuels affects the change of its physicochemical and operational characteristics: the dielectric constant and hydrophobicity of the medium decrease, the saturated vapor pressure increases, which improves the starting properties of the fuel; hydrophobization of the environment helps to reduce the corrosive properties of ethanol fuel per unit, as a result of which additional introduction of a corrosion inhibitor is not required; the bearing capacity of the fuel in the presence of brominated nanoparticles increases by 1.5 times compared to the base fuel with a corresponding decrease in damage to the metal surface of the friction pairs. It is the rearrangement of the secondary supramolecular structure of fuels in the presence of brominated carbon nanospheres that explains the multifunctionality of their influence on the physicochemical and chemmotological properties of ethanol motor fuels.

Photon correlation spectroscopy at low concentrations

1999 ◽  
Vol 30 ◽  
pp. S143-S144
Author(s):  
E.J. Nijman ◽  
J.C.M. Marijnissen ◽  
B. Scarlett
Keyword(s):  
Photon Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Photon Correlation ◽  
Low Concentrations

scholarly journals Low pH Potentiates Both Capsaicin Binding and Channel Gating of VR1 Receptors

2003 ◽  
Vol 122 (1) ◽  
pp. 45-61 ◽  
Author(s):  
Sujung Ryu ◽  
Beiying Liu ◽  
Feng Qin
Keyword(s):  
Single Channel ◽  
Channel Gating ◽  
General Mechanism ◽  
Low Concentrations ◽  
Excised Patches ◽  
High Concentrations ◽  
Activation Pathways ◽  
Single Channel Currents ◽  
Channel Currents ◽  
Important Basis

Capsaicin ion channels are highly expressed in peripheral nervous terminals and involved in pain and thermal sensations. One characteristic of the cloned VR1 receptor is its multimodal responses to various types of noxious stimuli. The channel is independently activated by capsaicin and related vanilloids at submicromolar range, by heat above 40°C, and by protons at pH below 6.5. Furthermore, simultaneous applications of two or more stimuli lead to cross sensitization of the receptor, with an apparent increase in the sensitivity to any individual stimulus when applied alone. We studied here the mechanism underlying such cross-sensitization; in particular, between capsaicin and pH, two prototypical stimuli for the channel. By analyzing single-channel currents recorded from excised-patches expressing single recombinant VR1 receptors, we examined the effect of pH on burst properties of capsaicin activation at low concentrations and the effect on gating kinetics at high concentrations. Our results indicate that pH has dual effects on both capsaicin binding and channel gating. Lowering pH enhances the apparent binding affinity of capsaicin, promotes the occurrences of long openings and short closures, and stabilizes at least one of the open conformations of the channel. Our data also demonstrate that capsaicin binding and protonation of the receptor interact allosterically, where the effect of one can be offset by the effect of the other. These results provide important basis to further understand the nature of the activation pathways of the channel evoked by different stimuli as well as the general mechanism underling the cross-sensitization of pain.

scholarly journals The influence of chemical composition on the saturated vapor pressure in biological motor fuels

2010 ◽  
Vol 42 (1) ◽  
Author(s):  
Є.В. Полункін ◽  
C.О. Зубенко ◽  
О.О. Гайдай ◽  
А.В. Струнгар ◽  
О.В. Кузнєцова
Keyword(s):  
Chemical Composition ◽  
Vapor Pressure ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Motor Fuels ◽  
Biological Motor

scholarly journals EFFECT OF DENSITY OF FUELS ON THE OPERATIONAL AND ECOLOGICAL CHARACTERISTICS OF MOTOR VEHICLES

2016 ◽  
pp. 108-116
Author(s):  
E. R. Magaril ◽  
R. Z. Magaril
Keyword(s):  
Negative Influence ◽  
Motor Vehicles ◽  
Processing Temperature ◽  
Motor Transport ◽  
Temperature Range ◽  
Ecological Characteristics ◽  
Oil Processing ◽  
Operational Characteristics ◽  
Motor Fuels ◽  
Diesel Fractions

Negative influence of the increased density of motor fuels on ecological and on operational characteristics of motor transport is proved. The complex of the technological solutions, aimed to decrease the density of the fuels, which are used, including a change of a ratio of capacities of oil processing, temperature range of boiling of gasoline and diesel fractions, introduction of additives into fuels and addition of butanes to gasolines is offered.

scholarly journals Evidence that the slow conformation change controlling NADH release from the enzyme is rate-limiting during the oxidation of propionaldehyde by aldehyde dehydrogenase

1987 ◽  
Vol 242 (3) ◽  
pp. 803-808 ◽  
Author(s):  
L F Blackwell ◽  
R L Motion ◽  
A K H MacGibbon ◽  
M J Hardman ◽  
P D Buckley
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Active Site ◽  
Catalytic Mechanism ◽  
General Mechanism ◽  
Conformation Change ◽  
Linear Least Squares ◽  
Decay Constants ◽  
Catalysed Oxidation ◽  
Low Concentrations ◽  
Rate Limiting

The displacement of NADH from the aldehyde dehydrogenase X NADH complex by NAD+ was followed at pH 7.0, and the data were fitted by a non-linear least-squares iterative procedure. At pH 7.0 the decay constants for the dissociation of NADH from aldehyde dehydrogenase X NADH complexes (1.62 +/- 0.09 s-1 and 0.25 +/- 0.004 s-1) were similar to the values previously determined by MacGibbon, Buckley & Blackwell [(1977) Biochem. J. 165, 455-462] at pH 7.6, and apparent differences between these values and those reported by Dickinson [(1985) Biochem. J. 225, 159-165] are resolved. Experiments at low concentrations of propionaldehyde show that isomerization of a binary E X NADH complex is part of the normal catalytic mechanism of the enzyme. Evidence is presented that the active-site concentration of aldehyde dehydrogenase is halved when enzyme is pre-diluted to low concentrations before addition of NAD+ and substrate. The consequences of this for the reported values of kcat. are discussed. A general mechanism for the aldehyde dehydrogenase-catalysed oxidation of propionaldehyde which accounts for the published kinetic data, at concentrations of aldehyde which bind only at the active site, is presented.

Ruthenate Ion Catalysed Oxidation of D-galactose and D-xylose by Alkaline Solution of Sodium Metaperiodate: A Kinetic Study

2005 ◽  
Vol 2005 (5) ◽  
pp. 304-310 ◽  
Author(s):  
Ashok Kumar Singh ◽  
N. Chaurasia ◽  
Shahla Rahmani ◽  
Jaya Srivastava ◽  
Ajaya Kumar Singh
Keyword(s):  
Ionic Strength ◽  
Activation Parameters ◽  
Zero Order ◽  
Oxidation Products ◽  
General Mechanism ◽  
Sodium Metaperiodate ◽  
First Order ◽  
Order Dependence ◽  
Catalysed Oxidation ◽  
Low Concentrations

The kinetics of ruthenate ion (RuO42–)-catalysed oxidation of D-galactose (Gal) and D-xylose (Xyl) by alkaline species of periodate, H2IO63–, in an aqueous solution at constant ionic strength shows zero order dependence on reducing sugar and first order dependence on RuO42–. First-order dependence of the reaction on periodate and OH- at their low concentrations tends to zero order in their higher concentration range. A slight increase in the rate of reaction with increase in ionic strength of the medium has also been observed. Various activation parameters have been computed. Lyxonic acid and threonic acid, along with formic acid, were identified as the main oxidation products for Gal and Xyl, respectively. A general mechanism involving bidentate interaction of a species of IO4– with a reactive species of sugar has been proposed.

scholarly journals IMPROVEMENT OF PERFORMANCE CHARACTERISTICS OF ETHANOL MOTOR FUELS THROUGH USE OF ADDITIVES BASED ON NANOSCALE CARBON CLUSTERS

2016 ◽  
Vol 6 ◽  
pp. 3-10 ◽  
Author(s):  
Olga Haidai ◽  
Vladimir Pilyavskiy ◽  
Yevgenij Shelud’ko ◽  
Yevgenij Polunkin
Keyword(s):  
Bearing Capacity ◽  
High Performance ◽  
Mechanical Load ◽  
Motor Fuel ◽  
Ethanol Fuel ◽  
Local Ordering ◽  
Motor Fuels ◽  
Multifunctional Additives ◽  
Improved Performance ◽  
Nanoscale Clusters

A new way to overcome the disadvantages of ethanol motor fuels by introducing of multifunctional additives based on carbon nanoscale clusters in their composition is given. It is shown that the modified nanoclusters contribute to the formation of supramolecular structure of ethanol fuels in the form of solvent domains around the nanoparticles. Orientation local ordering of these supramolecular structures changes such physicochemical properties of oxygenate fuels as dielectric constant and the load-bearing capacity of the liquid phase in the dynamic mechanical load. The influence of synthetic carbon spheroidal clusters on the corrosive properties of ethanol fuels is studied. It is shown that by using small amounts (0.01 % wt.) of nanocluster-based additives in the composition of mixed fuel E–85 it is unnecessary to introduce the anticorrosion additives. The effect of nanocarbon clusters on the tribological properties of ethanol motor fuels is studied. A decrease in damage of the metal surface for friction pairs of the fuel pumps is observed with the introduction of carboxylic nanoclusters into the ethanol fuel. This indicates the occurrence of friction processes in the hydrodynamic regime due to the increased bearing capacity of the fuel. It is shown that the introduction of additives based on carbon nanoscale clusters into the ethanol fuel allows to create a high-performance motor fuel with improved performance.

Shock wave reflection from a layer of a finely dispersed medium with low concentrations

2019 ◽  
Vol 14 (4) ◽  
pp. 279-283
Author(s):  
K.I. Bashirova ◽  
C.I. Mikhaylenko
Keyword(s):  
Shock Wave ◽  
Granular Medium ◽  
Wave Reflection ◽  
Solid Wall ◽  
Shock Wave Reflection ◽  
Two Phase ◽  
Reflected Wave ◽  
Low Concentrations ◽  
Dispersed Medium ◽  
Individual Particles

The paper investigates the propagation of a shock wave when interacting with a loosely packed granular medium. The continuous two-phase mathematical model presented in this work allows one to numerically describe the propagation of a shock wave in the channel of a shock tube, the achievement of a layer of granular filling by the shock wave, and the reflection of the wave. It was shown that the granular medium partially transmits the shock wave, but mostly corresponds to it. This reflection differs from the reflection of a shock wave from a solid wall. The nature of the reflection of the shock wave depends on the density of the granules. In particular, it has been shown that a granular medium of lower density, due to the increased mobility of individual particles, leads to some amplification of the reflected wave. It is also shown that the reflected wave in this case forms two pronounced peaks. It should be noted that the pressure passed in the layer of the granular medium, on the contrary, turns out to be the greater, the heavier the particles of the granular medium.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

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