The Bonding of Polychloroprene to Brass: Rate and Temperature Effects

1984 ◽  
Vol 57 (5) ◽  
pp. 1036-1055 ◽  
Author(s):  
G. R. Hamed ◽  
F-C. Liu
Keyword(s):  
Bond Strength ◽  
Low Temperatures ◽  
Temperature Effects ◽  
Adhesive Joints ◽  
Interfacial Region ◽  
Chemical Characteristics ◽  
Temperature Dependent ◽  
Minute Amount ◽  
Sulfur Level ◽  
Low Levels

Abstract The bonding of CR to brass shim has been studied at various test temperatures and rates using a T-peel geometry. Compounds without sulfur adhere relatively weakly to brass, and the bond strength is highly temperature dependent. The bonding strength is greatly enhanced, and its temperature dependence decreased, if the CR contains only a minute amount of sulfur. Adhesive joints made with rubber compositions containing just 0.5 phr or more of sulfur fail by cohesive tearing within the elastomeric layer, when tested at high temperatures; the bond strength thus exceeds the cohesive strength of the elastomer. At sufficiently low temperatures, the locus of fracture changes to the interfacial region. The temperature at which this transition occurs is independent of sulfur levels, suggesting that the bond strength is not very dependent on the sulfur level, at least for concentrations in the range of 0.5–9.0 phr. Unlike NR, which generally requires 3.0 phr or more of sulfur to obtain strong bonding, CR bonds tenaciously to brass when quite low levels of sulfur are present. Additionally, an ultra accelerator such as TMTM does not “destroy” the adhesion of CR to brass, as it does in the case of NR-brass bonding. This indicates that the sulfidation reaction at the interface between the rubber and brass is highly dependent on the chemical characteristics of the elastomer and not just the nature of the compounding ingredients.

Low Temperature Fault Isolation Using Soft Defect Localization

2012 ◽  
Author(s):  
Kristopher D. Staller
Keyword(s):  
Low Temperatures ◽  
Laser Scanning ◽  
Low Cost ◽  
Fault Isolation ◽  
Laser Scanning Microscopy ◽  
Cold Temperature ◽  
Multiple Point ◽  
Defect Localization ◽  
Low Levels

Abstract Cold temperature failures are often difficult to resolve, especially those at extreme low levels (< -40°C). Momentary application of chill spray can confirm the failure mode, but is impractical during photoemission microscopy (PEM), laser scanning microscopy (LSM), and multiple point microprobing. This paper will examine relatively low-cost cold temperature systems that can hold samples at steady state extreme low temperatures and describe a case study where a cold temperature stage was combined with LSM soft defect localization (SDL) to rapidly identify the cause of a complex cold temperature failure mechanism.

MAGNETIC BEHAVIOUR OF UPdAl, UCuGa AND UCuSn

1993 ◽  
Vol 07 (01n03) ◽  
pp. 850-854 ◽  
Author(s):  
V.H. TRAN ◽  
R. TROĆ
Keyword(s):  
Electrical Resistivity ◽  
Magnetic Susceptibility ◽  
Low Temperatures ◽  
Magnetic Behaviour ◽  
Type Structure ◽  
Complex Structures ◽  
Temperature Dependent ◽  
Antiferromagnetic Ordering

Magnetic susceptibility and electrical resistivity have been measured on UCuGa, UCu1+xSn1−x, (x=0 and 0.1), and UPdAl. The first two compounds, crystallizing in the hexagonal CaIn2-type structure, show at low temperatures an antiferromagnetic ordering probably with complex structures. UPdAl, which adopts the orthorhombic TiNiSi-type structure, was found to be a weakly temperature-dependent paramagnet down to 4.2 K.

scholarly journals Application of Temperature-Dependent Fluorescent Dyes to the Measurement of Millimeter Wave Absorption in Water Applied to Biomedical Experiments

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Nataliia Kuzkova ◽  
Oleksandr Popenko ◽  
Andrey Yakunov
Keyword(s):  
Millimeter Wave ◽  
Millimeter Waves ◽  
Temperature Effects ◽  
Fluorescent Dyes ◽  
Organic Dyes ◽  
Temperature Dependent ◽  
Wave Absorption ◽  
Biological Objects ◽  
Novel Method ◽  
Local Temperature Increase

Temperature sensitivity of the fluorescence intensity of the organic dyes solutions was used for noncontact measurement of the electromagnetic millimeter wave absorption in water. By using two different dyes with opposite temperature effects, local temperature increase in the capillary that is placed inside a rectangular waveguide in which millimeter waves propagate was defined. The application of this noncontact temperature sensing is a simple and novel method to detect temperature change in small biological objects.

scholarly journals Thermoregulation of Escherichia coli hchA Transcript Stability

2007 ◽  
Vol 189 (15) ◽  
pp. 5779-5781 ◽  
Author(s):  
Aviram Rasouly ◽  
Yotam Shenhar ◽  
Eliora Z. Ron
Keyword(s):  
Escherichia Coli ◽  
High Temperature ◽  
Low Temperatures ◽  
Temperature Dependent ◽  
Present Evidence ◽  
Transcript Stability

ABSTRACT The conserved chaperone Hsp31 of Escherichia coli is transcribed at low temperatures by σS and repressed by H-NS, whereas at high temperature, transcription is by σ70 independently of both σS and H-NS. Here we present evidence for an additional, novel, temperature-dependent control of Hsp31 expression by increased transcript stability.

scholarly journals Changes in soluble carbohydrates during storage of Caesalpinia echinata LAM. (Brazilwood) seeds, an endangered leguminous tree from the Brazilian Atlantic Forest

2006 ◽  
Vol 66 (2b) ◽  
pp. 739-745 ◽  
Author(s):  
I. S. Garcia ◽  
A. Souza ◽  
C. J. Barbedo ◽  
S. M. C. Dietrich ◽  
R. C. L. Figueiredo-Ribeiro
Keyword(s):  
Low Temperatures ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Soluble Carbohydrates ◽  
Leguminous Tree ◽  
Neutral Sugars ◽  
Main Tendency ◽  
Low Levels ◽  
Caesalpinia Echinata ◽  
Seed Storability

Caesalpinia echinata seeds stored in laboratory environmental conditions lose their viability in one month whilst under low temperatures germination is maintained for 18 months of storage. These seeds are tolerant to desiccation, keeping their viability up to 0.08 gH2O.gDW-1. Since soluble carbohydrates are believed to be involved with desiccation tolerance and seed storability, the aim of this work is to analyze the content and composition of soluble carbohydrates in C. echinata seeds during storage in paper bags (PB) and glass flasks (GF) at laboratory room (RT) and cool (CT) temperatures. In freshly harvested seeds, total soluble carbohydrates comprised approximately 10% of the dry weight, decreasing to ca. 8% over 18 months of storage at RT. In seeds stored at CT, sugars varied differently decreasing initially and being restored at the end of the analysis period. The main neutral sugars in seeds from all treatments were sucrose, fructose and glucose. Raffinose and stachyose were present as traces. Free myo-inositol and other cyclitols were also detected. The main tendency observed was the variation in levels of both glucose and fructose in relation to sucrose, the highest levels of monosaccharides which were found in seeds stored at CT. The values of glucose and fructose were practically constant in seeds stored in paper bags for 18 months at CT, decreasing consistently in the other treatments, mainly at RT. Sucrose contents remained relatively stable. Changes in soluble sugars during storage suggest that the loss of germinability of seeds of C. echinata could be associated with low levels of glucose and fructose in relation to sucrose.

Temperature acclimation of the caudal photoreceptor response in the crayfish Orconectes rusticus (Girard)

1988 ◽  
Vol 66 (5) ◽  
pp. 1168-1171 ◽  
Author(s):  
Jim H. Belanger
Keyword(s):  
Stimulus Intensity ◽  
Low Temperatures ◽  
Temperature Acclimation ◽  
Thermal Capacity ◽  
Maximum Frequency ◽  
Orconectes Rusticus ◽  
Temperature Dependent ◽  
Caudal Photoreceptor ◽  
Effects Of Temperature ◽  
Nerve Cords

Crayfish (Orconectes rusticus (Girard)) were acclimated for 3 weeks at 5 and 25 °C. The effects of temperature and temperature acclimation on the latency, maximum frequency, and sensitivity to stimulus intensity of the caudal photoreceptor response were examined in isolated abdominal nerve cords. Each of these components was temperature dependent. The maximum frequency of the response showed thermal capacity acclimation but latency did not. Caudal photoreceptor response was insensitive to stimulus intensity at low temperatures but acclimation improved sensitivity.

Incubation temperature effects on hatchling growth and metabolic rate in the African spurred tortoise, Geochelone sulcata

2009 ◽  
Vol 87 (1) ◽  
pp. 64-72 ◽  
Author(s):  
Day B. Ligon ◽  
Joseph R. Bidwell ◽  
Matthew B. Lovern
Keyword(s):  
Metabolic Rate ◽  
Conversion Efficiency ◽  
Temperature Effects ◽  
Null Hypothesis ◽  
Incubation Temperature ◽  
Resting Metabolic Rate ◽  
Temperature Dependent ◽  
Temperature Preference ◽  
Mass Conversion ◽  
Competing Hypotheses

We tested competing hypotheses regarding the persistence of temperature-dependent sex determination (TSD) in the African spurred tortoise (Geochelone sulcata (Miller, 1779)), by measuring the effects of incubation temperature (Tinc) on a suite of physiological and behavioral endpoints, including resting metabolic rate, yolk-to-tissue conversion efficiency, posthatching growth, and temperature preference. Correlations of these variables with Tinc could lend support to the hypothesis that TSD persists owing to sex-specific benefits of development at specific temperatures, whereas absence of Tinc effects support the null hypothesis that TSD persists simply because selection favoring alternate sex determining mechanisms is weak or absent. The metabolic rate Q10 value exhibited temporal variation and was higher immediately after hatching compared with 40 or 100 days posthatching, and mass conversion efficiency varied among clutches. Incubation temperature correlated inversely with duration of embryonic development, but did not influence yolk conversion efficiency, growth, or resting metabolic rate. Thus, our results provide little evidence indicating contemporary benefits of TSD, suggesting that TSD in G. sulcata is no longer evolutionarily adaptive but persists because selection against it and in favor of other sex-determining mechanisms is weak, or that TSD is an adaptive trait but for reasons not elucidated by this study.

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