Brittle Point of Rubber on Freezing

1942 ◽  
Vol 15 (2) ◽  
pp. 243-250
Author(s):  
M. L. Selker ◽  
G. G. Winspear ◽  
A. R. Kemp
Keyword(s):  
Low Temperatures ◽  
High Rate ◽  
Simple Method ◽  
Vulcanized Rubber ◽  
Synthetic Rubber ◽  
Brittle Point ◽  
New Material ◽  
Point Data ◽  
First Time

Abstract The need for a simple method of determining brittle points which would be adaptable to a large number of materials led the writers to develop the apparatus described below. There is presented here, for the first time, brittle point data on certain natural and synthetic rubber compositions. The study of the variation with temperature of the mechanical properties of elastomers is of immediate practical and theoretical interest. Recently Kistler attempted a correlation of temperature-strength data of polymers with their chemical structure. On the other hand, the increasing use of synthetic high polymers at low temperatures for insulation and mechanical purposes requires a more complete knowledge of their behavior under conditions of extreme cold. The determination of the brittle point offers a simple method for investigating the possible use of a new material at low temperatures. In 1928 Kohman and Peek described a method whereby a small strip of material at a known temperature was bent quickly through 90° by a hammer blow. They found that within rather wide limits the brittle temperature was independent of the sample dimensions and bending angle, but that a high rate of deformation was necessary for reproducible results. The brittle point was found to be definite and reproducible within ±2° C for the materials studied. Using this method, Kemp determined the brittle point range of crude and vulcanized rubber, balata, guttapercha, and paragutta.

New Theoretical Approach of the Fracture Ductility of Steels and its Relation with the Microscopy Structural Characterization

2010 ◽  
Vol 449 ◽  
pp. 96-103
Author(s):  
Viacheslav A. Yermishkin ◽  
Pedro A. Tamayo Meza ◽  
N. Muñoz Aguirre ◽  
M. Mendez Arait ◽  
D. Vilchis Leonardo
Keyword(s):  
Mechanical Characteristics ◽  
Theoretical Determination ◽  
Large Size ◽  
Fracture Ductility ◽  
Mechanical Methods ◽  
New Material ◽  
Dislocational Structure ◽  
First Time ◽  
Microscopy Images

It is well known that the formation of a highly hardening state of the standard steels is related with the improvement of its mechanical characteristics, which means an increment in the ductility of the fracture. Commonly, the ductility of the fracture is measured by means of mechanical methods involving large size and geometrical special shape of the sample. Satisfy these requirements in the initial steps of the development of a new material, or during the treatment for improving the hardness, is a dif ficult task. The present work shows the theoretical determination of the ductility of the fracture when the researchers have a small piece of the sample. Also, from the analysis of microscopy images, by the first time, it is demonstrated that an ultra-hardening state of the steel corresponds to a nano-fragmented dislocational structure in accordance to the theory.

scholarly journals Mesoporous oxide films grown on Sn foil using various anodizing modes in alkaline electrolyte

2021 ◽  
Vol 340 ◽  
pp. 01050
Author(s):  
Tatyana Vasilyeva ◽  
Nikolai Uvarov
Keyword(s):  
Tin Oxide ◽  
Voltage Drop ◽  
Oxide Films ◽  
Alkaline Electrolyte ◽  
Porous Structures ◽  
Simple Method ◽  
Galvanostatic Mode ◽  
Mesoporous Oxide ◽  
First Time

The mesoporous structures of tin oxide were obtained by a simple method of one-stage electrochemical anodizing of Sn foil in 1M NaOH in various anodizing modes. Anodizing in the pulse potentiostatic mode allowed determination of actual value of the voltage drop on the anode. For the first time the possibility of obtaining mesoporous oxide films on the surface of tin using galvanostatic mode of anodizing was demonstrated. It was found that the surface morphology of the obtained tin oxide layers is strongly dependent on the anodizing mode. Based on the data obtained, a two-stage mechanism was proposed for the growth of porous structures on the surface of tin in the galvanostatic mode including initial formation of the layer of SnO·xH2O which is subsequently oxidized to SnO2·xH2O mesoporouslayer.

Development of a Method for Simultaneous Determination of Two Stilbenes and Four Anthraquinones from Polygonum Cuspidatum by RP-HPLC

2019 ◽  
Vol 102 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Jianye Yan ◽  
Yuanqing Wang ◽  
Hongnian Wu ◽  
Zhicheng Sun ◽  
Shihan Tan ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Polygonum Cuspidatum ◽  
Chinese Medicinal Herb ◽  
Simple Method ◽  
Rp Hplc ◽  
First Time

Abstract Background: Polygonum Cuspidatum Sieb. et Zucc. (named Huzhang in China) is a traditional and popular Chinese medicinal herb used in removing jaundice, clearing heat-toxin, improving blood circulation, expelling stasis, dispelling wind and dampness, repelling phlegm, and suppressing cough. It is widely used in drug and functional food fields and distributed throughout the world, including in China, Japan, and North America. Objective: To control the quality of Polygonum Cuspidatum, an effective, reliable, and simple method for simultaneous determination of two stilbenes (polydatin, resveratrol) and four anthraquinones (emodin, physcion, rhein, and anthraglycoside B) was developed and validated for the first time in this study by reversed-phase HPLC (RP-HPLC). Methods: Separation was carried out on Agilent C18 column (250 × 4.6 mm I.D., 5 μm) with acetonitrile and 0.10% aqueous phosphoric acid as mobile phase and gradient elution at a flow rate of 0.8 mL/min. Detection was conducted with mobile wavelength at 30°C. Results: Good validation of the method including linearity, precision, repeatability, and recovery was performed. The contents of the studied analytes are significantly different, and resveratrol and rhein in particular existed in greater fluctuation among the samples. Conclusion: A simple, reliable, and sensitive method has been successfully established and applied to the analysis for simultaneous determination of the target compounds in 11 batches of samples. Highlights: Separation and quantitative analysis of two stilbenes and four anthraquinones from P. cuspidatum were developed by RP-HPLC. This method is convenient, sensitive, and accurate and can provide a reliable basis for further applications of P. cuspidatum in drug or food fields.

A New Method for Determining the Resistance of Soft-Rubber Products to Low Temperatures

1945 ◽  
Vol 18 (2) ◽  
pp. 401-404 ◽  
Author(s):  
J. Aengeneyndt ◽  
W. Kesternich
Keyword(s):  
Low Temperatures ◽  
Simple Technique ◽  
New Method ◽  
Simple Method ◽  
Vulcanized Rubber ◽  
Soft Rubber

Abstract A simple method for testing the behavior of vulcanized rubber at low temperatures is described. In this method test-specimens in the form of strips prepared from finished goods, such as packing, hose, etc., are tested by a simple technique, without the necessity of mathematical calculations or the plotting of graphs. It is recommended that the hardening point be used as a criterion of behavior of vulcanized rubber in service at low temperatures, i.e., its resistance to cold. When this method is used, this hardening temperature should be 5° to 15° C below the lowest outside temperature at which the particular product must still operate satisfactorily.

scholarly journals The effect of temperature on the viscosity of neon

1928 ◽  
Vol 119 (783) ◽  
pp. 578-590 ◽  
Keyword(s):  
Low Temperatures ◽  
Large Range ◽  
Effect Of Temperature ◽  
Theoretical Formula ◽  
Lennard Jones ◽  
Two Temperatures ◽  
The Difference ◽  
First Time ◽  
Crucial Test

The experiments described in this paper have been carried out to obtain accurate data with respect to the variation of the viscosity of neon with temperature, over a range of several hundred degrees Centigrade. This has been rendered more desirable in view of the recent publication of a new theoretical formula for the variation of viscosity of a gas with temperature by J. E. Lennard-Jones, which he has applied with conspicuous success to various gases. In the case of neon, however, it was not possible to make a test of the formula as the experimental data are so sparse, only one observer, A. O. Rankine, having made measurements upon its viscosity, and then at only two temperatures. Accordingly, as neon should provide a crucial test between Lennard-Jones’ formula and that of Sutherland, the method already applied by the author J to the case of air was suitably modified for use with a gas of which the quantity available was strictly limited and values of the viscosity obtained from 444-5° C. downwards. Owing, however, to the increase in the quantity of neon required as the temperature was reduced, it was not found possible to take observations at a temperature lower than — 78-4° C. Unfortunately, it is only at low temperatures that the difference between the two formulæ becomes marked, and hence the results obtained have not been sufficient to provide a really crucial test between them. The determination of the viscosity over a large range does, however, for the first time, provide sufficient data for a reliable comparison to be made of the molecular properties of neon, as determined from its viscosity with the values of the same properties deduced from other sources.

The Dissolution of Vulcanized Rubbers and Its Bearing on Problems of Rubber Analysis

1954 ◽  
Vol 27 (2) ◽  
pp. 535-541
Author(s):  
W. C. Wake
Keyword(s):  
Iodine Value ◽  
Transmission Spectra ◽  
Infrared Transmission ◽  
Roller Mill ◽  
Vulcanized Rubber ◽  
Synthetic Rubber ◽  
Determining Factors ◽  
Analytical Procedures ◽  
Value Determination

Abstract Dissolution of a sample of vulcanized rubber is a necessary preliminary to several analytical procedures, e.g., the determination of iodine value or total fillers. If an infallible and convenient agent were available for this process, then doubtless other analytical procedures would be possible of development or improvement and examination of infrared transmission spectra of vulcanized samples would prove a feasible means of identification. Although decalin and nitrobenzene have been widely and satisfactorily used for natural rubber (polyisoprene), there have been several references in the literature to difficulties encountered with the most widely used synthetic rubber, GR-S. Devices to overcome these difficulties include comminution on a roller mill, swelling the sample in strong swelling agents before transferring to the solvent to be used for the dissolution, and grinding on a rubber mill with a plasticizer. All these must be regarded as being of the nature of palliatives, knowledge of the nature of the dissolution process being the real need before the best condition for carrying it out can be decided on. It is shown in this paper that the process is essentially oxidative in nature and, provided that the solvent and rubber are miscible at the temperature of the dissolution, temperature and efficient aeration are the most important rate-determining factors. The nature of the solvent is, of course, of importance with respect to the analytic procedure attempted as all solvents are not suitable for iodine value determination.

Gas-chromatographic determination of polyol profiles in cerebrospinal fluid.

1978 ◽  
Vol 24 (4) ◽  
pp. 545-548 ◽  
Author(s):  
S L Smith ◽  
M Novotny ◽  
E L Weber
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Cerebrospinal Fluid ◽  
Chromatographic Determination ◽  
Gas Chromatography Mass Spectrometry ◽  
Glass Capillary ◽  
Simple Method ◽  
Glass Capillary Columns ◽  
First Time

Abstract We describe a simple method for collectively determining polyols in the cerebrospinal fluid. The method consists of protein removal, sample derivatization, and gas chromatography of the trimethylsilylated polyols, with use of glass capillary columns. Nine major polyol constituents, the structures of which were verified by combined gas chromatography/mass spectrometry, can be simultaneously assayed. The presence of three polyols in the cerebrospinal fluid is reported here for the first time.

Brittle Points of Natural and Synthetic Rubber Stocks

1944 ◽  
Vol 17 (1) ◽  
pp. 92-99
Author(s):  
Ross E. Morris ◽  
Robert R. James ◽  
Theodore A. Werkenthin
Keyword(s):  
Low Temperatures ◽  
Cold Resistance ◽  
Practical Significance ◽  
Synthetic Rubber ◽  
Point Test ◽  
Brittle Point ◽  
Lower Temperature ◽  
Natural And Synthetic

Abstract The slow-bend brittle point test does not have the same practical significance as the Bell Telephone Laboratories brittle point test because most rubber articles which are exposed to low temperatures in service are required to withstand fairly rapid flexing. If the slow-bend brittle point test were used as a criterion of the cold resistance of these rubber articles, it might qualify the rubbers for a lower temperature than they could safely withstand in service. The brittle point test developed by the Bell Telephone Laboratories is simple and sensitive. It is believed that this test may advantageously be used to study all cold resistance problems where damage to the rubber itself and not increase in stiffness is the first consideration.

Development of a simple method for the determination of single nucleotide polymorphisms

2010 ◽  
Vol 34 (8) ◽  
pp. S75-S75
Author(s):  
Weifeng Zhu ◽  
Zhuoqi Liu ◽  
Daya Luo ◽  
Xinyao Wu ◽  
Fusheng Wan
Keyword(s):  
Single Nucleotide Polymorphisms ◽  
Nucleotide Polymorphisms ◽  
Simple Method ◽  
Single Nucleotide
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