The Constitution of Rubber According to Its Swelling in Liquids

1930 ◽  
Vol 3 (4) ◽  
pp. 576-585
Author(s):  
Paul Bary
Keyword(s):  
Experimental Study ◽  
Vapor Pressure ◽  
Saturated Vapor ◽  
Point Of View ◽  
Single Sample ◽  
Saturation Point ◽  
Liquid Solutions ◽  
Before And After ◽  
The Stability

Abstract In various publications we have previously shown that in many cases it is advantageous to consider jellies as formed of a polymerized colloidal substance, the length of the molecular chains being easily changed according to the conditions of the system and unlike one another at all times in a single sample. These chains retain free affinities at their extremities to which can be linked so-called solvating groups arising from the solvent or from soluble substances contained in the jelly. The present work refutes the interpretation given to recent experiments on the vapor pressure of jellies and confirms in certain new ways this constitution. (1) The experiments of Stamberger on the vapor pressure of rubber jellies and their consistency before and after a prolonged mastication do not support the Harries hypothesis on the stability of the rubber molecule, but merely show that the theory of true liquid solutions is not applicable to jellies. (2) Based on the idea that polymerization changes with solvation, it is easily shown that the relative swelling in a solvent and in its saturated vapor are not contradictory with the principles of thermodynamics, as it would seem, but on the contrary proceed normally and could have been predicted. (3) In the study by Scott on the slow but unlimited swelling of rubber beyond the saturation point, this author has come to assume that swelling is a double phenomenon, which confirms our point of view. (4) The experimental study of the contraction of rubber during swelling shows that this effect does not change its sign at any moment and that consequently the change of sign of the heat evolved in this same process has a cause distinct from that of the initial swelling; perhaps it is to be attributed to the chemical phenomenon of solvation.

scholarly journals Phenomenology of NNLO jet production at the LHC and its impact on parton distributions

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Rabah Abdul Khalek ◽  
Stefano Forte ◽  
Thomas Gehrmann ◽  
Aude Gehrmann-De Ridder ◽  
Tommaso Giani ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Systematic Investigation ◽  
Point Of View ◽  
Dijet Production ◽  
Parton Distributions ◽  
Jet Production ◽  
Before And After ◽  
Inclusive Jet ◽  
8 Tev ◽  
The Stability

Abstract We present a systematic investigation of jet production at hadron colliders from a phenomenological point of view, with the dual aim of providing a validation of theoretical calculations and guidance to future determinations of parton distributions (PDFs). We account for all available inclusive jet and dijet production measurements from ATLAS and CMS at 7 and 8 TeV by including them in a global PDF determination, and comparing to theoretical predictions at NNLO QCD supplemented by electroweak (EW) corrections. We assess the compatibility of the PDFs, specifically the gluon, obtained before and after inclusion of the jet data. We compare the single-inclusive jet and dijet observables in terms of perturbative behaviour upon inclusion of QCD and EW corrections, impact on the PDFs, and global fit quality. In the single-inclusive case, we also investigate the role played by different scale choices and the stability of the results upon changes in modelling of the correlated experimental systematics.

Experimental Study of Shell-Side Fogging Condensation of a Mixture

2017 ◽  
Author(s):  
Hongfang Gu ◽  
Haiyang Guo ◽  
Haijun Wang ◽  
Yuqiang Gu
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Vapor Pressure ◽  
Gas Phase ◽  
High Speed ◽  
Saturated Vapor ◽  
Saturation Temperature ◽  
Bulk Temperature ◽  
Transfer Performance ◽  
Shell Side

Fog formation occurs if the vapor pressure in the gas-phase is higher than the saturated vapor pressure and the bulk temperature is lower than its saturation temperature (supersaturated) for condensation in the presence of non-condensable gases. Generally, fogging is formation of entrained small droplets mixing in the vapor-gas stream, and the vapor condenses at the mist-flow and share-controlled flow regime. The phenomenon and mechanism of fogging need to be considered for determining condensation rate and separation of the condensate from vapor-gas phase for the down-stream process. The experimental study of shell-side condensation using steam mixing with non-condensable air was conducted in a shell-side horizontal baffled tube bundle. Experimental data has been obtained including visualization findings using high-speed photograph. The characteristics of fog formation related to the heat and mas transfer performance are analyzed based on experimental data and observation. The general equation for determining fog formation (degree of supersaturation) is evaluated with experimental data. Results confirm that the transition band of fogging formation is in the range of S = 1.0 to 1.75. This paper presents experimental data and visualization findings on fogging characteristics and heat transfer performance for condensation in the presence of non-condensable gas.

Modification of motor gasoline with bioethanol in the cavitation field

2020 ◽  
pp. 56-65
Author(s):  
S.V. Boichenko ◽  
◽  
A.V. Yakovlieva ◽  
O.B. Tselishchev ◽  
V.G. Lanetsky ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Octane Number ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Physical Stability ◽  
Motor Fuel ◽  
Before And After ◽  
Cavitation Field ◽  
Blended Fuels ◽  
Petroleum Fuels

Today, the use of bioethanol as an alternative motor fuel is quite relevant. Bioethanol is generally used as an additive to traditional petroleum fuels. The addition of bioethanol has a positive effect on increasing the evaporation and detonation resistance of gasoline. However, the addition of bioethanol alone may not be sufficient to fully address these issues. This article presents the results of a study of the influence of bioethanol content and cavitation field parameters on the quality of gasoline: evaporation and octane number. To determine the effect of cavitation treatment of gasoline-ethanol mixture on the physical stability of the fuel and evaporation, the content of narrow fractions, the percentage of fractions in the fuel, and the saturated vapor pressure before and after cavitation were determined. The optimal content of the biocomponent, which increases the evaporation of gasoline, has been established. The results of the change of octane number depending on the intensity of cavitation treatment for gas condensate with the addition of bioethanol are also presented. The influence of bioethanol content on the increase of octane number during cavitation treatment was determined. It is shown that the production of blended fuels by compounding with the use of cavitation treatment allows to obtain a gasoline-reference mixture with significantly better evaporation characteristics, in particular in terms of fractional composition and saturated vapor pressure, compared to gasoline-ethanol mixtures obtained by conventional mechanical compounding. In addition, it was found that the use of cavitation treatment can increase the octane number of fuels. The introduc-tion of ethanol can further increase their octane number. Thus, the introduction of ethanol and the use of cavitation treatment has a synergistic effect on improving the anti-knock characteristics of gasoline.

scholarly journals Stabilita stoja po únave brušných svalov

2016 ◽  
Vol 10 (1) ◽  
pp. 103-109
Author(s):  
Daniel Gurín ◽  
Jan Novotný
Keyword(s):  
Experimental Study ◽  
Stability Index ◽  
Abdominal Muscles ◽  
Stability Parameters ◽  
Balance System ◽  
Before And After ◽  
The Stability ◽  
Biodex Balance System

In the pilot experimental study eight men with an average age of 33.5 ± 3.64 years were tested. The probands were tested on the Biodex Balance System before and after the exercise of the abdominal muscles. Exercise was carried out to the subjectively perceived maximum. The file was deliberately composed of mentally and physically trained individuals. Evaluated was the stability index, the smaller the nominal value, the better the stability. After the workout stability parameters were significantly worse than before the exercise (p = 0.025). The fatigue of the abdominal muscles thus negatively affects the stability of the stand.

The stability of dislocation networks under various oxygen-doping conditions in superconducting Bi2Sr2CaCu2Oy single crystals and their influence on the flux pinning properties

1994 ◽  
Vol 52 ◽  
pp. 802-803
Author(s):  
Y. Feng ◽  
X. Y. Cai ◽  
R. J. Kelley ◽  
D. C. Larbalestier
Keyword(s):  
Single Crystals ◽  
Oxygen Content ◽  
Basal Plane ◽  
Flux Pinning ◽  
Pinning Centers ◽  
Before And After ◽  
Anomalous Peak ◽  
Basal Plane Dislocation ◽  
The Stability ◽  
Further Development

The issue of strong flux pinning is crucial to the further development of high critical current density Bi-Sr-Ca-Cu-O (BSCCO) superconductors in conductor-like applications, yet the pinning mechanisms are still much debated. Anomalous peaks in the M-H (magnetization vs. magnetic field) loops are commonly observed in Bi2Sr2CaCu2Oy (Bi-2212) single crystals. Oxygen vacancies may be effective flux pinning centers in BSCCO, as has been found in YBCO. However, it has also been proposed that basal-plane dislocation networks also act as effective pinning centers. Yang et al. proposed that the characteristic scale of the basal-plane dislocation networksmay strongly depend on oxygen content and the anomalous peak in the M-H loop at ˜20-30K may be due tothe flux pinning of decoupled two-dimensional pancake vortices by the dislocation networks. In light of this, we have performed an insitu observation on the dislocation networks precisely at the same region before and after annealing in air, vacuumand oxygen, in order to verify whether the dislocation networks change with varying oxygen content Inall cases, we have not found any noticeable changes in dislocation structure, regardless of the drastic changes in Tc and the anomalous magnetization. Therefore, it does not appear that the anomalous peak in the M-H loops is controlled by the basal-plane dislocation networks.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

Clinically Meaningful Change

Methodology ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 97-105
Author(s):  
Rodrigo Ferrer ◽  
Antonio Pardo
Keyword(s):  
Effect Size ◽  
False Negative ◽  
False Negative Rate ◽  
Point Of View ◽  
Skewed Distribution ◽  
Effect Sizes ◽  
False Negatives ◽  
Large Size ◽  
Before And After ◽  
Post Test

Abstract. In a recent paper, Ferrer and Pardo (2014) tested several distribution-based methods designed to assess when test scores obtained before and after an intervention reflect a statistically reliable change. However, we still do not know how these methods perform from the point of view of false negatives. For this purpose, we have simulated change scenarios (different effect sizes in a pre-post-test design) with distributions of different shapes and with different sample sizes. For each simulated scenario, we generated 1,000 samples. In each sample, we recorded the false-negative rate of the five distribution-based methods with the best performance from the point of view of the false positives. Our results have revealed unacceptable rates of false negatives even with effects of very large size, starting from 31.8% in an optimistic scenario (effect size of 2.0 and a normal distribution) to 99.9% in the worst scenario (effect size of 0.2 and a highly skewed distribution). Therefore, our results suggest that the widely used distribution-based methods must be applied with caution in a clinical context, because they need huge effect sizes to detect a true change. However, we made some considerations regarding the effect size and the cut-off points commonly used which allow us to be more precise in our estimates.

Arthroscopy in Arthrosis: Is It Worth it? A case Presentation

2018 ◽  
Vol 69 (8) ◽  
pp. 2232-2235
Author(s):  
Marius Moga ◽  
Mark Edward Pogarasteanu ◽  
Antoine Edu
Keyword(s):  
Clinical Status ◽  
Loose Body ◽  
Point Of View ◽  
The Other ◽  
Joint Range Of Motion ◽  
Objective Evidence ◽  
Before And After ◽  
Total Knee ◽  
Joint Range

The role of arthroscopy in incipient and mild arthrosis, even combined with proximal tibial ostetomy, is well known and well documented. On the other hand, its role in the treatment of advanced arthrosis of the large joints, especially the knee, is a subject of controversy. The proponents of the use of arthroscopy in advanced arthrosis claim that meniscectomy, synovectomy, ostophytectomy, chondral lesion stabilization, arthroscopic release, plica and loose body removal greatly improve the quality of life for most patients, especially if followed by the use of viscoelastic injection, by diminishing pain and improving joint range of motion. The opponents claim that, even though the advantages are clear in the cases that refuse arthroplasty, in all the other cases the surgical indication should be total knee arthroplasty, as the clinical relief is temporary, but with all the risks of a surgical intervention. We have conducted an overview of the recent literature, in order to find objective evidence to sustain either point of view. We focused on articles published that included an objective measurement of before and after clinical status through clinical scores and objective measurements. We also focused on the follow-up period and on the evolution of the pathology after arthroscopy.

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