Effect of Temperature Exposure on the Flexural Mechanical Behavior of Two Pultruded Composites

Most organisms are exposed to bouts of warm temperatures during development, yet we know little about how variation in the timing and continuity of heat exposure influences biological processes. If heat waves increase in frequency and duration as predicted, it is necessary to understand how these bouts could affect thermally sensitive species, including reptiles with temperature-dependent sex determination (TSD). In a multi-year study using fluctuating temperatures, we exposed Trachemys scripta embryos to cooler, male-producing temperatures interspersed with warmer, female-producing temperatures (heat waves) that varied in either timing during development or continuity and then analysed resulting sex ratios. We also quantified the expression of genes involved in testis differentiation ( Dmrt1 ) and ovary differentiation ( Cyp19A1 ) to determine how heat wave continuity affects the expression of genes involved in sexual differentiation. Heat waves applied during the middle of development produced significantly more females compared to heat waves that occurred just 7 days before or after this window, and even short gaps in the continuity of a heat wave decreased the production of females. Continuous heat exposure resulted in increased Cyp19A1 expression while discontinuous heat exposure failed to increase expression in either gene over a similar time course. We report that even small differences in the timing and continuity of heat waves can result in drastically different phenotypic outcomes. This strong effect of temperature occurred despite the fact that embryos were exposed to the same number of warm days during a short period of time, which highlights the need to study temperature effects under more ecologically relevant conditions where temperatures may be elevated for only a few days at a time. In the face of a changing climate, the finding that subtle shifts in temperature exposure result in substantial effects on embryonic development becomes even more critical.

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The Effect of Temperature on Microstructure and Mechanical Behavior of the Vacuum Brazed Joint of Ti-46.5Al-5Nb Alloy and 42CrMo Steel

Materials Science Forum - PRICM-5 ◽

10.4028/0-87849-960-1.829 ◽

2005 ◽

pp. 829-832

Author(s):

W. Liu ◽

Q. Gao ◽

W. Cong ◽

Jian Ting Guo

Keyword(s):

Mechanical Behavior ◽

Effect Of Temperature ◽

42Crmo Steel ◽

Brazed Joint

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EFFECTS OF COLD EXPOSURE ON YOUNG GROWING LAMBS

Canadian Journal of Animal Science ◽

10.4141/cjas84-046 ◽

1984 ◽

Vol 64 (2) ◽

pp. 403-410 ◽

Cited By ~ 3

Author(s):

G. E. McBRIDE ◽

R. J. CHRISTOPHERSON

Keyword(s):

Cold Exposure ◽

Dry Matter ◽

Bone Growth ◽

Nitrogen Retention ◽

Exposed Group ◽

Effect Of Temperature ◽

Treatment Groups ◽

Morphological Differences ◽

Temperature Exposure ◽

Key Words Cold

The performance and development of young Iambs housed at 0 ± 1 °C or 21 ± 1 °C were compared in two experiments. Despite similar nutrient intakes for both treatment groups, preweaning growth rate of the cold-exposed lambs tended to be reduced. Bone growth from 4 to 9 wk of age revealed a significant effect of temperature on metatarsal length (P < 0.05). By 10 wk of age morphological differences between the two groups were apparent, especially in terms of smaller ear dimensions (P < 0.01), head (P < 0.10) and metatarsal lengths (P < 0.05) of the cold-exposed lambs. Leg bone lengths after slaughter (13 wk of age) also tended to be shorter for the lambs housed at 0 °C. Organ weights measured after 11 wk of differential temperature exposure were similar for both groups except for slightly increased abomasal and thyroid weights (P < 0.10) in the cold-exposed group. Dry matter and nitrogen digestibilities of a concentrate ration fed to the weaned lambs were not affected by treatment, although nitrogen retention (g/day, g/g digestible N intake) was significantly lowered (P < 0.05) as a result of cold exposure. Key words: Cold, growth, digestion, morphology, lambs

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The Relationship Between Ambient Temperature and FPG, A Series of Cross-Sectional Studies in Guangdong Province, China

10.21203/rs.3.rs-36042/v1 ◽

2020 ◽

Author(s):

Jiali Luo ◽

Guanhao He ◽

Yanjun Xu ◽

Zihui Chen ◽

Xiaojun Xu ◽

...

Keyword(s):

Glycemic Control ◽

Ambient Temperature ◽

Additive Model ◽

Guangdong Province ◽

Effect Of Temperature ◽

Cluster Sampling ◽

Cross Sectional ◽

Exposure Response ◽

Different Populations ◽

Temperature Exposure

Abstract Background: There existed evidence that the incidence and glycemic control rate of T2DM have seasonal variation, which can be attributed to the effect of temperature on FPG. The present study aimed to examine the associations between short-term ambient temperature exposure and FPG among different populations and calculate temperature-FPG association adjusted prevalence and glycemic control rate of T2DM.Methods: Four cross-sectional health surveys with 26,350 respondents were conducted in Guangdong Province from 2007 to 2015. Multistage cluster sampling was used to recruit study participants. Gaussian generalized additive model was employed to evaluate the associations between daily mean ambient temperature and FPG among different populations (total, non-T2DM, old-T2DM and new-T2DM populations). Prevalence and glycemic control rate of T2DM were calculated based on the exposure-response association between temperature and FPG. Results: The exposure-response curve of temperature and FPG were downward parabola in total, non-T2DM and old-T2DM populations, while the curve was “U”-shaped but not significant in new T2DM population. When temperature increased from 10th percentile to 50th percentile, the FPG significantly decreased 0.14 (95%CI: -0.17, -0.11) mmol/L, 0.11 (95%CI: -0.12, -0.11) and 0.44 (95%CI: -0.80, -0.08) in total, non-T2DM and old-T2DM populations, respectively. When temperature increased from 50th to 90th percentile, the FPG significantly decreased 0.19 (95%CI: -0.22, -0.16) mmol/L, 0.17 (95%CI: -0.17, -0.17) and 0.51 (95%CI: -0.79, -0.23) in total, non-T2DM and old-T2DM populations, respectively. The alteration of rate related to the temperature difference was observed from 5℃ to 30℃, with gently decreases from 10.03% to 9.39% in prevalence of T2DM and greatly increases from 32.1% to 58.6% in glycemic control rate of T2DM, respectively.Conclusion: FPG, the prevalence and glycemic control rate of T2DM are affected by ambient temperature, which suggests temperature and FPG association should be considered and adjusted when estimating T2DM epidemiology and developing clinical management of T2DM.

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Influence of Pressing Temperature on Wood Properties

10.21741/9781644901755-6 ◽

2022 ◽

Author(s):

M. Romanenko

Keyword(s):

High Performance ◽

Water Saturation ◽

Wood Properties ◽

Mechanical Action ◽

Raw Material ◽

Effect Of Temperature ◽

Pressing Temperature ◽

Long Time ◽

Temperature And Pressure ◽

Temperature Exposure

Abstract. Obtaining wood with high performance properties on the basis of chemical and mechanical action as a result of optimization of technological processes and the use of temperature exposure. The initial raw material is hardwood (aspen, alder), which are little used in construction and in the production of finishing materials. The condition for obtaining wood with high operating properties (increasing density, strength, reducing water saturation, ensuring the dimensional stability of samples for a long time) is the ability of wood as a natural polymer to change properties under the combined effect of temperature and pressure.

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A Study on Clay Particle Effect to the Mechanical Properties of Pultruded Composites Under Shear Loading

Volume 13: Processing and Engineering Applications of Novel Materials ◽

10.1115/imece2007-43597 ◽

2007 ◽

Author(s):

J. Y. Park ◽

T. Fay ◽

T. Davis

Keyword(s):

Mechanical Properties ◽

Mechanical Behavior ◽

Glass Fiber ◽

Polymer Composites ◽

Shear Loading ◽

Experimental Program ◽

Shape Effect ◽

Particle Effect ◽

Pultruded Composites ◽

Hexagonal Platelet

A micromechanical investigation aimed at examining the mechanical behavior of pultruded polymer composites containing hexagonal platelet shaped fillers under shear loading is presented. Micromechanical models that account for the presence of inhomogeneities such as the clay fillers and voids in matrix materials were developed to estimate the inplane shear properties. The analytical results were obtained based on the consideration of shape effect of filler and void, and then were compared with the properties determined by an experimental program. For the experiments, pultruded polymer composites containing clay fillers and voids as well as E-glass fiber and vinylester resin were selected, analyzed and tested under shear loading. The effects of the volume fractions of the constituents on the mechanical properties of the composites were also investigated.

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Study on Tensile Properties of CFRP Plates under Elevated Temperature Exposure

Materials ◽

10.3390/ma12121995 ◽

2019 ◽

Vol 12 (12) ◽

pp. 1995 ◽

Cited By ~ 3

Author(s):

Yongxin Yang ◽

Yanju Jiang ◽

Hongjun Liang ◽

Xiaosan Yin ◽

Yue Huang

Keyword(s):

Tensile Strength ◽

Elastic Modulus ◽

Elevated Temperature ◽

Tensile Properties ◽

Failure Mode ◽

Elevated Temperatures ◽

Strain Curve ◽

Effect Of Temperature ◽

Temperature Exposure ◽

The Impact

Elevated temperature exposure has a negative effect on the performance of the matrix resin in Carbon Fiber Reinforced Plastics (CFRP) plates, whereas limited quantitative research focuses on the deteriorations. Therefore, 30 CFRP specimens were designed and tested under elevated temperatures (10, 30, 50, 70, and 90 °C) to explore the degradations in tensile properties. The effect of temperature on the failure mode, stress-strain curve, tensile strength, elastic modulus and elongation of CFRP plates were investigated. The results showed that elevated temperature exposure significantly changed the failure characteristics. When the exposed temperature increased from 10 °C to 90 °C, the failure mode changed from the global factures in the whole CFRP plate to the successive fractures in carbon fibers. Moreover, with temperatures increasing, tensile strength and elongation of CFRP plates decreases gradually while the elastic modulus shows negligible change. Finally, the results of One-Way Analysis of Variance (ANOVA) show that the degradation of the tensile strength of CFRP plates was due to the impact of elevated temperature exposure, rather than the test error.

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