Intrinsic strength and the structure of glass

2020 ◽  
Vol 61 (6) ◽  
pp. 239-247
Author(s):  
C. R. Kurkjian ◽  
◽  
P. K. Gupta ◽  
Keyword(s):  
Composition Dependence ◽  
Structural Information ◽  
High Strength ◽  
Laboratory Conditions ◽  
Normal Laboratory ◽  
Intrinsic Strength ◽  
Glass Compositions

Intrinsic strength is the strength of a glass without extrinsic flaws. Knowledge of the composition dependence of the intrinsic strength is important both technologically for the development of high strength glass compositions and theoretically as it may provide important structural information. Intrinsic strength is easy to define but difficult to measure experimentally. In this paper we discuss intrinsic (σ*) strength measured in normal laboratory conditions as well as the inert intrinsic (σ0*) strength. We define these terms in a rigorous manner and indicate how to gauge if they have been measured by developing a set of criteria. Based on these criteria, we tabulate those values of intrinsic strengths that have been measured to date.

Centrifugal Manometer

1959 ◽  
Vol 81 (3) ◽  
pp. 341-348
Author(s):  
J. F. Kemp
Keyword(s):  
High Sensitivity ◽  
Working Fluid ◽  
Quick Response ◽  
Laboratory Conditions ◽  
Wide Range ◽  
Maximum Range ◽  
Normal Laboratory

The operating principles and mechanical construction of a micromanometer, which utilizes air in lieu of a liquid as working fluid, are described. Some of the noteworthy features of the instrument include its high sensitivity and accuracy, quick response, wide range, and ease of manipulation. Differential pressures of the order of 5 × 10−3 mm water gage can be measured with an error of 1 per cent under normal laboratory conditions. The maximum range of the prototype described is 25 mm water gage, and the corresponding error at this value amounts to about 0.25 per cent.

A Glass Durability Model Based on Understanding Glass Chemistry and Structural Configurations of the Glass Constituents

1996 ◽  
Vol 432 ◽  
Author(s):  
Xiangdong Feng ◽  
Todd B. Metzger
Keyword(s):  
Redox State ◽  
Composition Dependence ◽  
Structural Bond ◽  
Data Set ◽  
Consistency Test ◽  
First Order ◽  
Structural Configurations ◽  
The Individual ◽  
Better Than ◽  
Glass Compositions

AbstractAn improved structural bond strength (SBS) model has been developed to quantify the correlation between glass compositions and their chemical durabilities. The SBS model assumes that the strengths of the bonds between cations and oxygens and the structural roles of the individual elements in the glass are the predominant factors controlling the composition dependence of the chemical durability of glasses. The structural roles of oxides in glass are classified as network formers, network breakers, and intermediates. The structural roles of the oxides depend on glass composition and the redox state of oxides. A12O3, ZrO2, Fe2O3, and B2O2 are assigned as network formers only when there are sufficient alkalis to bind with these oxides. CaO can also improve durability by sharing non-bridging oxygen with alkalis, relieving Si0 2 from alkalis. The binding order to alkalis is AI2O3>ZrO2>Fe2O 2>B2O2>CaO>SiO2. The percolation phenomenon in glass is also taken into account. The concentration of network formers has to reach a critical value for a glass to become durable; durable glasses are sufficient in network formers and have a complete network structure; poor durability glasses are deficient in network formers and the network is incomplete and discontinuous. The SBS model is capable of correlating the 7-day product consistency test durability of 42 low-level waste glasses with their composition with an R2 of 0.87, which is better than 0.81 obtained with an eight-coefficient empirical first-order mixture model on the same data set.

scholarly journals THE ROLE OF COMPLEMENT IN RESISTANCE TO ENDOGENOUS AND EXOGENOUS INFECTION WITH A COMMON MOUSE PATHOGEN, CORYNEBACTERIUM KUTSCHERI

1966 ◽  
Vol 124 (4) ◽  
pp. 689-699 ◽  
Author(s):  
Linda D. Caren ◽  
L. T. Rosenberg
Keyword(s):  
Survival Advantage ◽  
Mouse Serum ◽  
Equal Frequency ◽  
Laboratory Conditions ◽  
Immune Hemolysis ◽  
The Common ◽  
Deficient Mice ◽  
Normal Laboratory ◽  
Better Than

In mice, the presence or absence of a single complement (C') component, called hc1, is controlled by two alleles at the Hc locus. The sera of mice which lack this C' component do not manifest C'-mediated immune hemolysis. When challenged with the common mouse pathogen, Corynebacterium kutscheri, mice possessing hemolytic C' fare slightly better than C'-deficient mice. When mice harboring latent C. kutscheri are administered hydrocortisone, which depresses mouse serum C' levels, pseudotuberculosis is activated with equal frequency in mice of both C' types. These data suggest that in at least one situation the presence of the complete hemolytic C' system may be advantageous to the mouse. In contrast, evidence is presented which shows that under normal laboratory conditions, C'-deficient B10.D2 "old line" mice (Hc0/Hc0) have a survival advantage over C'-positive B10.D2 "new line" mice (Hc1/Hic1) during the first 3 wk of life. It is therefore concluded that mouse hemolytic C' has a balanced survival value—that is, under one set of conditions it may be advantageous, whereas in another situation, it may be disadvantageous.

Volatility of Technical Chlordane: An Alternative Approach for Quantitative Measurement of Residues

1970 ◽  
Vol 53 (5) ◽  
pp. 1015-1017
Author(s):  
Don W Thompson
Keyword(s):  
Quantitative Measurement ◽  
Method Of Calculation ◽  
Laboratory Conditions ◽  
Alternative Method ◽  
Alternative Approach ◽  
Total Mixture ◽  
High Bias ◽  
Fluorescent Lighting ◽  
Normal Laboratory

Abstract Volatility studies on technical chlordane under normal laboratory conditions of temperature and fluorescent lighting indicate that only the contribution of trans- and cis-chlordane to the total mixture remains fairly constant. Using this approach, an alternative method of calculation has been evaluated for chlordane residues. Calculation of residues by comparison of GLC peaks for total trans- and cischlordane results in values within ±5% of those calculated from the total area, after correction for a uniform high bias.

scholarly journals Experiments in Time Perception

1964 ◽  
Vol 9 (5) ◽  
pp. 396-410 ◽  
Author(s):  
Daniel Cappon ◽  
Robert Banks
Keyword(s):  
Time Perception ◽  
Subjective Time ◽  
Temporal Experience ◽  
Testing Conditions ◽  
Laboratory Conditions ◽  
Reliable Effect ◽  
Past Life ◽  
Normal Laboratory

Experimentation was carried out to test for a relationship between subjective time perception and ability to make temporal judgements. The performance of 20 depersonalized and derealized patients and 20 controls, was compared on a variety of tests of time judgement administered under normal laboratory conditions and under conditions which have been shown to induce or amplify distortions in subjective temporal experience. The results failed to indicate any reliable relationship between subjective temporal experience and ability to make time judgements. The performance of patients did not differ reliably from that of controls under any of the testing conditions; exposure to distorting conditions did not have a reliable effect on temporal performance and Ss who reported temporal distortions either in their past life or while actually performing the tests of time judgement, failed to perform differently from Ss who did not report distortions.

scholarly journals Regulation of Hypercompetence in Legionella pneumophila

2004 ◽  
Vol 186 (12) ◽  
pp. 3814-3825 ◽  
Author(s):  
Jessica A. Sexton ◽  
Joseph P. Vogel
Keyword(s):  
Legionella Pneumophila ◽  
Bacterial Species ◽  
Single Species ◽  
Great Promise ◽  
Dna Uptake ◽  
Bacterial Strains ◽  
Aerobic Growth ◽  
Laboratory Conditions ◽  
Normal Laboratory

ABSTRACT Although many bacteria are known to be naturally competent for DNA uptake, this ability varies dramatically between species and even within a single species, some isolates display high levels of competence while others seem to be completely nontransformable. Surprisingly, many nontransformable bacterial strains appear to encode components necessary for DNA uptake. We believe that many such strains are actually competent but that this ability has been overlooked because standard laboratory conditions are inappropriate for competence induction. For example, most strains of the gram-negative bacterium Legionella pneumophila are not competent under normal laboratory conditions of aerobic growth at 37°C. However, it was previously reported that microaerophilic growth at 37°C allows L. pneumophila serogroup 1 strain AA100 to be naturally transformed. Here we report that another L. pneumophila serogroup 1 strain, Lp02, can also be transformed under these conditions. Moreover, Lp02 can be induced to high levels of competence by a second set of conditions, aerobic growth at 30°C. In contrast to Lp02, AA100 is only minimally transformable at 30°C, indicating that Lp02 is hypercompetent under these conditions. To identify potential causes of hypercompetence, we isolated mutants of AA100 that exhibited enhanced DNA uptake. Characterization of these mutants revealed two genes, proQ and comR, that are involved in regulating competence in L. pneumophila. This approach, involving the isolation of hypercompetent mutants, shows great promise as a method for identifying natural transformation in bacterial species previously thought to be nontransformable.

scholarly journals Light-Induced Passivation of Si by Iodine Ethanol Solution

2008 ◽  
Vol 1123 ◽  
Author(s):  
Bhushan Sopori ◽  
Przemyslaw Rupnowski ◽  
Jesse Appel ◽  
Debraj Guhabiswas ◽  
LaTecia Anderson-Jackson
Keyword(s):  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Ethanol Solution ◽  
Experimental Results ◽  
Material Parameters ◽  
Laboratory Conditions ◽  
Wafer Cleaning ◽  
Normal Laboratory ◽  
Si Wafer

AbstractWe report on our observations of light-activated passivation (LIP) of Si surfaces by iodine-ethanol (I-E) solution. Based on our experimental results, the mechanism of passivation appears to be related to dissociation of iodine by the photo-carriers injected from the Si wafer into the I-E solution. The ionized iodine (I−) then participates in the formation of a Si-ethoxylate bond that passivates the Si surface. Experiments with a large number of wafers of different material parameters indicate that under normal laboratory conditions, LIP can be observed only in some samples–samples that have moderate minority-carrier lifetime. We explain this observation and also show that wafer cleaning plays an extremely important role in passivation.

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