Effects of temperature and thermal gradient on thermocouple psychrometer measurements

Géotechnique ◽  
2011 ◽  
Vol 61 (10) ◽  
pp. 875-885 ◽  
Author(s):  
H.M. ABUEL-NAGA ◽  
A. BOUAZZA
Keyword(s):  
Thermal Gradient ◽  
Thermocouple Psychrometer ◽  
Effects Of Temperature

Temperature Effects on Soil Suction for Compacted Clay Soils

2013 ◽  
Vol 723 ◽  
pp. 527-534
Author(s):  
Shu Rong Yang ◽  
Wei Hsing Huang ◽  
Shao Hung Chung
Keyword(s):  
Water Content ◽  
Clayey Soil ◽  
Expansive Soils ◽  
Soil Suction ◽  
Compacted Clay ◽  
Subgrade Soils ◽  
Thermocouple Psychrometer ◽  
Effects Of Temperature ◽  
Paper Method ◽  
Water Contents

An investigation was conducted to determine the effects of temperature, compaction water content, and compaction efforts on soil suction of two expansive subgrade soils. For this purpose, two expansive soils were statically compacted at target water contents ranging from 5% to 20%. This made it possible to explore a broad spectrum of compaction conditions. Filter paper method and thermocouple psychrometer were used to measure soil suction at temperatures ranging from 10°C to 60°C. Experimental results show that compaction water content, compaction effort, and temperature have influences on soil suction. As water content increases, the influences of compaction effort and temperature on suction become less significant. Finally multiple regression formulations for predicting the soil suction of as-compacted clayey soil were established.

scholarly journals Effects of Temperature on Seed Germination of Plantago lanceolata and Management in Carya illinoinensis Production

Plants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 308
Author(s):  
Timothy L. Grey ◽  
Kayla M. Eason ◽  
Lenny Wells ◽  
Nicholas T. Basinger
Keyword(s):  
Seed Germination ◽  
Thermal Gradient ◽  
Plantago Lanceolata ◽  
Carya Illinoinensis ◽  
Dichlorophenoxyacetic Acid ◽  
Greenhouse Experiments ◽  
Effects Of Temperature ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Diurnal Temperatures

Plantago lanceolata L. (buckhorn plantain) is an encroaching winter weed described as one of the most successful noncultivated colonizing species around the world. Control of P. lanceolata in southeastern USA Carya illinoinensis (Wangenh.) K. Koch production has not been studied, nor has the role of temperature on germination using a thermal gradient table. Seed of P. lanceolata collected from a Georgia C. illinoinensis grove were tested for the effects of temperature over time to establish differences in effects on germination using a thermal gradient table. Temperatures ranged from 13.5 to 30.5 °C for 288 h. Cumulative P. lanceolata seed germination was 66% occurring at 17.8 °C at 242 h. Over the 288 h experiment, maximum P. lanceolata germination was 27% occurring at 17.0 °C, 187 h after initiation. Control of P. lanceolata with residual herbicides, or in combination with 2,4-dichlorophenoxyacetic acid (2,4-D) was evaluated in the interrow of C. illinoinensis groves containing Trifolium repens L., and in greenhouse experiments. Pre- and post-emergent herbicides included indaziflam, halosulfuron-methyl, and simazine applied alone, or in combination with 2,4-D in late autumn after P. lanceolata emergence in a C. illinoinensis grove. Indaziflam in combination with 2,4-D controlled P. lanceolata greater than 90% when applied in C. illinoinensis groves and greenhouse experiments. Halosulfuron-methyl and simazine applied alone, or in combination with 2,4-D, provided 67% or less P. lanceolata control in the grove experiments, and 83% or less in greenhouse experiments. Results suggested that herbicide applications should be made during the time when diurnal temperatures are between 15 and 30 °C, while abiding pre-harvest interval restrictions. Post- and pre-emergent herbicides may aid in controlling emerged weeds and reducing further weed emergence during the autumn of that year.

A novel approach to studying the effects of temperature on soil biogeochemistry using a thermal gradient bar

2006 ◽  
Vol 22 (3) ◽  
pp. 267-273 ◽  
Author(s):  
N. Fenner ◽  
D. J. Dowrick ◽  
M. A. Lock ◽  
C. R. Rafarel ◽  
C. Freeman
Keyword(s):  
Thermal Gradient ◽  
Soil Biogeochemistry ◽  
Novel Approach ◽  
Effects Of Temperature

scholarly journals Thermal adaptation constrains the temperature dependence of ecosystem metabolism

2017 ◽  
Author(s):  
Daniel Padfield ◽  
Chris Lowe ◽  
Angus Buckling ◽  
Richard Ffrench-Constant ◽  
Elisa Schaum ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Thermal Gradient ◽  
Gross Primary Production ◽  
Thermal Adaptation ◽  
Functional Trait ◽  
Evolutionary Mechanisms ◽  
Photosynthetic Physiology ◽  
Ecosystem Level ◽  
Effects Of Temperature

ABSTRACTGross primary production (GPP) is the largest flux in the carbon cycle, yet its response to global warming is highly uncertain. The temperature sensitivity of GPP is directly linked to photosynthetic physiology, but the response of GPP to warming over longer timescales could also be shaped by ecological and evolutionary processes that drive variation community structure and functional trait distributions. Here, we show that selection on photosynthetic traits within and across taxa dampen the effects of temperature on GPP across a catchment of geothermally heated streams. Autotrophs from cold streams had higher photosynthetic rates and after accounting for differences in biomass among sites, rates of ecosystem-level GPP were independent of temperature, despite a 20 ºC thermal gradient. Our results suggest that thermal adaptation constrains the long-term temperature dependence of GPP, and highlights the importance of considering physiological, ecological and evolutionary mechanisms when predicting how ecosystem-level processes respond to warming.

scholarly journals A temperature dependent trophic cascade modifies temperature dependence of ecosystem function

2017 ◽  
Author(s):  
Jessica Garzke ◽  
Stephanie J. Connor ◽  
Ulrich Sommer ◽  
Mary I. O’Connor
Keyword(s):  
Community Structure ◽  
Temperature Dependence ◽  
Ecosystem Function ◽  
Trophic Cascade ◽  
Thermal Gradient ◽  
Phytoplankton Biomass ◽  
Oxygen Flux ◽  
Ecosystem Functions ◽  
Temperature Dependent ◽  
Effects Of Temperature

AbstractEcological communities and their ecosystem functions are sensitive to temperature, and aquatic habitats worldwide continue to experience unprecedented warming. Understanding ecological effects of warming requires linking empirical evidence to theories that allow projection to unobserved conditions. Metabolic scaling theory and its tests suggest that warming accelerates ecosystem functions (e.g., oxygen flux), yet this prediction apparently contradicts community-level studies suggesting warming is a stressor that can reduce ecosystem function. We sought to reconcile these predictions with an experimental test of the hypothesis that cascading trophic interactions modify the temperature-dependence of community structure and ecosystem fluxes. In a series of independent freshwater ecosystems exposed to a thermal gradient, we found that warmer temperatures strengthened the trophic cascade increased and indirectly changed community structure by altering grazer species composition and phytoplankton biomass. Temperature-driven community shifts only modestly affected the temperature dependence of net ecosystem oxygen fluxes. Over the 10 °C thermal gradient, NPP and ER increased ∼2.7-fold among ecosystems, while standing phytoplankton biomass declined by 85-95%. The exponential increase in oxygen flux over the thermal gradient, as well as monotonic declines in phytoplankton standing stock, suggested no threshold effects of warming across systems. We also observed temperature variation over time, within ecosystems. For phytoplankton biomass, temporal variation had the opposite effect to spatial variation, suggesting that within-community temporal change in community structure was not predicted by space-for-time substitution. We conclude that food chain length can modify effects of temperature on ecosystem fluxes, but that temperature can still have continuous and positive effects on ecosystem fluxes, consistent with patterns based on large-scale, macroecological comparisons. Changes in community structure, including temperature dependent trophic cascades, may be compatible with prevailing and predictable effects of temperature on ecosystem functions related to fundamental effects of temperature on metabolism.Statement of authorshipJG & MIO designed the study, MIO & US provided materials, JG & SJC performed research and collected data, JG performed zooplankton analysis, SJC performed phytoplankton analysis, JG & MIO performed modeling work, analyzed data output, and wrote the first draft, and all authors contributed substantially to reviews

EFFECTS OF TEMPERATURE AND WORK ON METABOLISM, BODY TEMPERATURE, AND INSULATION: RESULTS WITH MICE

1952 ◽  
Vol 30 (1) ◽  
pp. 90-98 ◽  
Author(s):  
J. S. Hart
Keyword(s):  
Critical Temperature ◽  
Body Temperature ◽  
Thermal Gradient ◽  
Substantial Improvement ◽  
Cold Environment ◽  
Effects Of Temperature

For inactive mice, metabolism below the critical temperature was proportional to the thermal gradient, and body temperature and insulation were constant in animals acclimated to 6 °C., but not in those acclimated to 20 °C. For active mice, the same work caused the same increase in metabolism at all temperatures, but metabolism during work was not proportional to the thermal gradient. During work, with decreasing temperature, body temperature was relatively stable in 6 °C. mice but fell appreciably in 20 °C. mice. Over-all insulation was lower in working than in inactive animals, but in the 6 °C. acclimated mice there was a substantial improvement in insulation during work as the temperature decreased. Reports on other animals and humans also suggest that work may lower insulation. When work decreases insulation, much of the heat produced by the work, unlike that produced by SDA, may not be available for maintaining body temperature in a cold environment.

scholarly journals Shakedown Behaviour of Composite Cylinders With Cross Hole

2010 ◽  
Author(s):  
Haofeng Chen ◽  
Weihang Chen ◽  
Tianbai Li ◽  
James Ure
Keyword(s):  
Thermal Gradient ◽  
Composite Cylinder ◽  
Plastic Limit ◽  
Temperature Dependent ◽  
Matching Method ◽  
Numerical Examples ◽  
Effects Of Temperature ◽  
Shakedown Limit ◽  
Composite Cylinders ◽  
Linear Matching Method

In this study, both the lower and upper bound shakedown limits of a closed-end composite cylinder with or without a cross hole subject to constant internal pressure and a cyclic thermal gradient are calculated by the Linear Matching Method (LMM). Convergence for upper and lower bound shakedown limit of the composite cylinders is sought and shakedown limit interaction diagrams of the numerical examples identifying the regions of reverse plastic limit and ratchet limit are presented. The effects of temperature-dependent yield stress, materials discontinuities, composite cylinder thickness and the existence of cross hole on the shakedown limits are discussed for different geometry parameters. Finally, a safety shakedown envelope is created by formulating the shakedown limit results of different composite material and cylinder thickness ratios with different cross hole sizes.

Fission Gas Bubbles in Fractured UO2

1968 ◽  
Vol 26 ◽  
pp. 286-287
Author(s):  
O. M. Katz
Keyword(s):  
Electron Microscopy ◽  
Thermal Gradient ◽  
Gas Bubbles ◽  
Inert Gas ◽  
Thermal Gradients ◽  
Fission Gas ◽  
Beam Heating ◽  
Limited Application ◽  
Bubble Characteristics ◽  
Electron Beam Heating

The swelling of irradiated UO2 has been attributed to the migration and agglomeration of fission gas bubbles in a thermal gradient. High temperatures and thermal gradients obtained by electron beam heating simulate reactor behavior and lead to the postulation of swelling mechanisms. Although electron microscopy studies have been reported on UO2, two experimental procedures have limited application of the results: irradiation was achieved either with a stream of inert gas ions without fission or at depletions less than 2 x 1020 fissions/cm3 (∼3/4 at % burnup). This study was not limited either of these conditions and reports on the bubble characteristics observed by transmission and fractographic electron microscopy in high density (96% theoretical) UO2 irradiated between 3.5 and 31.3 x 1020 fissions/cm3 at temperatures below l600°F. Preliminary results from replicas of the as-polished and etched surfaces of these samples were published.

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