scholarly journals Referee comments on Craw et al. "The temperature change shortcut: effects of mid-experiment temperature changes on the deformation of polycrystalline ice"

2020 ◽  
Author(s):  
Nicolas Stoll
Keyword(s):  
Temperature Change ◽  
Temperature Changes ◽  
Polycrystalline Ice

scholarly journals SIMULATION AND EXPERIMENT OF EXTINCTION OR ADAPTATION OF BIOLOGICAL SPECIES AFTER TEMPERATURE CHANGES

2005 ◽  
Vol 16 (03) ◽  
pp. 389-392 ◽  
Author(s):  
D. STAUFFER ◽  
H. ARNDT
Keyword(s):  
Sexual Reproduction ◽  
Temperature Change ◽  
Biological Species ◽  
Biological Aging ◽  
Heterotrophic Flagellates ◽  
Temperature Changes ◽  
Penna Model ◽  
Simulation And Experiment ◽  
Unicellular Organisms

Can unicellular organisms survive a drastic temperature change, and adapt to it after many generations? In simulations of the Penna model of biological aging, both extinction and adaptation were found for asexual and sexual reproduction as well as for parasex. These model investigations are the basis for the design of evolution experiments with heterotrophic flagellates.

Evaluation of Controlling Transient Ramp Times Using Piping Methodologies When Considering Environmental Fatigue (Fen) Effects

2007 ◽  
Author(s):  
J. Michael Davis ◽  
Gary L. Stevens
Keyword(s):  
Stress Response ◽  
Strain Rate ◽  
Temperature Change ◽  
Technical Support ◽  
Task Group ◽  
Temperature Changes ◽  
Plant Operations ◽  
Asme Code ◽  
Thermal Transient ◽  
Parametric Analyses

As a part of the 2006 ASME Code support being provided by the Materials Reliability Program (MRP) Fatigue Issue Task Group (ITG), and later the Technical Support Committee (TSC), it is desired to develop a solution that establishes the most severe transient for design purposes when environmental fatigue rules are considered. This problem does not have an obvious answer, since the environmental fatigue multiplier (e.g., Fen) expressions depend on the strain rate during a transient. The strain rate in a thermal transient is dependent on the ramp time of the temperature change. Classically, fatigue analysis has been performed by conservatively considering that temperature changes are instantaneous (e.g., ramp time = zero). This results in maximizing the stress response. But, all other things being equal, Fen effects are minimum at instantaneous changes. Previous work performed by the MRP to support 2005 ASME Code activities has investigated how Fen × Usage varies with ramp time and has concluded that Fen × Usage maximizes at a small but definitely non-zero ramp time [1]. The implications of non-zero transient ramp times are that difficulties arise in both specifying ahead of time and qualifying the component for appropriate ramp times and, at the same time, not creating a situation whereby plant operations are required to proceed at a specified pace to remain design compliant. Therefore, it is desirable to have the qualifying fatigue analyses cover all conceivable ramp times such that the operator neither has to: (a) be limited to a minimum pace, nor (b) confirm through observations that the pace is at least as fast as assumed in the design. This paper summarizes qualifying fatigue analyses that have been performed using piping methodologies to define bounding ramp times for a variety of piping geometry and material configurations. The intent of these analyses is to provide the component designer with a set of parametric tools that can be used to easily design components without the need for iterative fatigue analyses to determine the bounding conditions when Fen rules are considered. In addition, the tool developed to perform the parametric analyses is available for future use by the designer should more specific analyses be required.

scholarly journals Thermal Time Constant of PV Roof Tiles Working under Different Conditions

2019 ◽  
Vol 9 (8) ◽  
pp. 1626 ◽  
Author(s):  
Kurz ◽  
Nawrowski
Keyword(s):  
Energy Balance ◽  
Thermal Resistance ◽  
Temperature Change ◽  
Environmental Parameters ◽  
Thermal Capacity ◽  
Electrical Characteristics ◽  
Legal Regulations ◽  
Temperature Changes ◽  
Different Types ◽  
The Relationship

This paper presents different types of photovoltaic (PV) roof tiles integrating PV cells with roof covering. Selected elastic photovoltaic roof tiles were characterised for their material and electrical characteristics. Practical aspects of using PV roof tiles are discussed, alongside the benefits and drawbacks of their installation on the roof. Thermal resistance, heat transfer coefficient and thermal capacity were identified for elastic PV roof tiles and roof construction built of boards and PV roof tiles, according to valid standards and legal regulations. The resistance–capacity (RC) models of PV roof tiles and roofs are proposed according to the time constants identified for the analysed systems. The energy balance of the studied systems (PV roof tiles alone and the roof as a whole) is presented, based on which temperature changes in the PV cells of the roof tiles working under different environmental conditions were identified. The timing of PV cells’ temperature change obtained by material data and energy balance analyses were compared. The relationship between the temperature change times of PV cells and the thermal resistance and heat capacity of the whole system are demonstrated, alongside environmental parameters.

Adaptation as a Mechanism for Gain Control in an Insect Thermoreceptor

2008 ◽  
Vol 100 (4) ◽  
pp. 2137-2144 ◽  
Author(s):  
Harald Tichy ◽  
Harald Fischer ◽  
Ewald Gingl
Keyword(s):  
Temperature Change ◽  
Thermal Effects ◽  
Gain Control ◽  
Input Function ◽  
High Gain ◽  
Oscillation Period ◽  
Rate Of Change ◽  
Temperature Changes ◽  
Precise Information ◽  
Instantaneous Temperature

Adaptation controls the gain of the input-function of the cockroach's cold cell during slowly oscillating changes in temperature. When the oscillation period is long, the cold cell improves its gain for the rate of temperature change at the expense of its ability to code instantaneous temperature. When the oscillation period is brief, however, the cold cell reduces this gain and improves its sensitivity for instantaneous temperature. This type of gain control has an important function. When the cockroach ventures from under cover and into moving air, the cold cell is confronted constantly with brief changes in temperature. To be of any use, a limit in the gain for the rate of change seems to be essential. Without such a limit, the cold cell will always indicate temperature change. The decrease in gain for the rate of change involves an increase in gain for instantaneous temperature. Therefore the animal receives precise information about the temperature at which the change occurs and can seek an area of different temperature. If the cockroach ventures back under cover, the rate of change will become slow. In this situation, a high gain improves the ability to signal slow temperature changes. The cockroach receives the early warning of slow fluctuations or even creeping changes in temperature. A comparison of the cold cell's responses with the temperature measured inside of small, cylindrical model objects indicates that coding characteristic rather than passive thermal effects of the structures enclosing the cold cell are responsible for the observed behavior.

scholarly journals Climate-induced population displacements in a 4 ° C+ world

2011 ◽  
Vol 369 (1934) ◽  
pp. 182-195 ◽  
Author(s):  
François Gemenne
Keyword(s):  
Climate Change ◽  
Temperature Change ◽  
Temperature Rise ◽  
Sub Saharan Africa ◽  
Population Movements ◽  
Temperature Changes ◽  
Policy Responses ◽  
Sub Saharan

Massive population displacements are now regularly presented as one of the most dramatic possible consequences of climate change. Current forecasts and projections show that regions that would be affected by such population movements are low-lying islands, coastal and deltaic regions, as well as sub-Saharan Africa. Such estimates, however, are usually based on a 2 ° C temperature rise. In the event of a 4 ° C+ warming, not only is it likely that climate-induced population movements will be more considerable, but also their patterns could be significantly different, as people might react differently to temperature changes that would represent a threat to their very survival. This paper puts forward the hypothesis that a greater temperature change would affect not only the magnitude of the associated population movements, but also—and above all—the characteristics of these movements, and therefore the policy responses that can address them. The paper outlines the policy evolutions that climate-induced displacements in a 4 ° C+ world would require.

scholarly journals The isothermal layer of the atmosphere and atmospheric radiation

1909 ◽  
Vol 82 (551) ◽  
pp. 43-70 ◽  
Keyword(s):  
High Pressure ◽  
Temperature Gradient ◽  
Temperature Change ◽  
Atmospheric Temperature ◽  
Atmospheric Radiation ◽  
Average Height ◽  
Vertical Temperature Gradient ◽  
Vertical Temperature ◽  
Temperature Changes ◽  
Isothermal Layer

The investigation of the upper air by means of balloons carrying self-recording instruments, which have furnished values for the atmospheric temperature up to heights between 15 and 20 kilometres, has revealed the existence of an abnormal change in the vertical temperature gradient. After a fairly uniform fall, with increasing altitude, of about 6° C. per kilometre, a height is reached above which the temperature changes very little, sometimes increasing, sometimes diminishing slowly. The phenomenon was first noticed by M. Teisserenc de Bort in a communication to the Société de Physique in June, 1899. He improved his apparatus and made further investigations, in many cases sending up the balloons by night to eliminate any possible insolation effects. He found the average height, at which the change began, to be about 11 kilometres. He discovered also that the height was greater near the centre of high pressure areas than in low pressure areas, the average heights for the two cases being 12-5 and 10 kilometres respectively. More recently he found that the height increased with approach towards the equator and that near the equator, ballons-sondes , ascending to 15 kilometres, had failed to reach this layer if it existed there. He proposed to call this layer, in which little temperature change occurred, the “Isothermal Layer of the Atmosphere,” and the name has been generally accepted.

scholarly journals The temperature change shortcut: effects of mid-experiment temperature changes on the deformation of polycrystalline ice

2021 ◽  
Vol 15 (5) ◽  
pp. 2235-2250
Author(s):  
Lisa Craw ◽  
Adam Treverrow ◽  
Sheng Fan ◽  
Mark Peternell ◽  
Sue Cook ◽  
...  
Keyword(s):  
Strain Rate ◽  
Temperature Change ◽  
Constant Temperature ◽  
Ice Sheets ◽  
Strain Rates ◽  
Temperature Step ◽  
Ice Shelves ◽  
Polycrystalline Ice ◽  
Long Time ◽  
Run Time

Abstract. It is vital to understand the mechanical properties of flowing ice to model the dynamics of ice sheets and ice shelves and to predict their behaviour in the future. We can increase our understanding of ice physical properties by performing deformation experiments on ice in laboratories and examining its mechanical and microstructural responses. However, natural conditions in ice sheets and ice shelves extend to low temperatures (≪-10 ∘C), and high octahedral strains (> 0.08), and emulating these conditions in laboratory experiments can take an impractically long time. It is possible to accelerate an experiment by running it at a higher temperature in the early stages and then lowering the temperature to meet the target conditions once the tertiary creep stage is reached. This can reduce total experiment run-time by > 1000 h; however it is not known whether this could affect the final strain rate or microstructure of the ice and potentially introduce a bias into the data. We deformed polycrystalline ice samples in uniaxial compression at −2 ∘C before lowering the temperature to either −7 or −10 ∘C, and we compared the results to constant-temperature experiments. Tertiary strain rates adjusted to the change in temperature very quickly (within 3 % of the total experiment run-time), with no significant deviation from strain rates measured in constant-temperature experiments. In experiments with a smaller temperature step (−2 to −7 ∘C) there is no observable difference in the final microstructure between changing-temperature and constant-temperature experiments which could introduce a bias into experimental results. For experiments with a larger temperature step (−2 to −10 ∘C), there are quantifiable differences in the microstructure. These differences are related to different recrystallisation mechanisms active at −10 ∘C, which are not as active when the first stages of the experiment are performed at −2 ∘C. For studies in which the main aim is obtaining tertiary strain rate data, we propose that a mid-experiment temperature change is a viable method for reducing the time taken to run low-stress and low-temperature experiments in the laboratory.

scholarly journals Phasic Temperature Change Patterns Affect Growth and Tuberization in Potatoes

1994 ◽  
Vol 119 (4) ◽  
pp. 775-778 ◽  
Author(s):  
Weixing Cao ◽  
Theodore W. Tibbitts
Keyword(s):  
Temperature Change ◽  
Vapor Pressure Deficit ◽  
Dry Weight ◽  
Tuber Initiation ◽  
Tuber Development ◽  
Temperature Changes ◽  
Shoot Dry Weight ◽  
Controlled Environments ◽  
Total Plant ◽  
Two Temperature

This study determined the responses of potato (Solanum tuberosum L., cv. Norland) plants to various patterns of air temperature changes over different growth periods (phasic temperature changes). In each of two experiments under controlled environments, eight treatments of temperature changes were carried out in two growth rooms maintained at 17 and 22C and a constant vapor pressure deficit of 0.60 kPa and 14-hour photoperiod. Plants were grown for 63 days after transplanting of tissue culture plantlets in 20-liter pots containing peat-vermiculite mix. Temperature changes were imposed on days 21 and 42, which were essentially at the beginning of tuber initiation and tuber enlargement, respectively, for this cultivar. Plants were moved between two temperature rooms to obtain eight temperature change patterns: 17-17-17, 17-17-22, 17-22-17, 22-17-17, 17-22-22, 22-17-22, 22-22-17, and 22-22-22C over three 21-day growth periods. At harvest on day 63, total plant dry weight was higher for the treatments beginning with 22C than for those beginning with 17C, with highest biomass obtained at 22-22-17 and 22-17-17C. Shoot dry weight increased with temperature increases from 17-17-17 to 22-22-22C during the three growth periods. Tuber dry weight was highest with 22-17-17C, and lowest with 17-17-22 and 17-22-22C. With 22-17-17C, both dry weights of stolons and roots were lowest. Total tuber number and number of small tubers (<2.5 cm) were highest with 17-17-17 and 17-17-22C, and lowest with 17-22-22 and 22-22-22C, whereas number of medium tubers (2.5-5.0 cm) was highest with 22-17-22C, and number of large tubers (>5.0 cm) was highest with 22-17-17C. This study indicates that tuber development of potatoes is optimized with a phasic pattern of high temperature during early growth and low temperature during later growth.

scholarly journals Coal Temperature Variation Mechanism during Gas Desorption Process

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
T. Yang ◽  
B. S. Nie ◽  
Q. S. Ye ◽  
P. Chen
Keyword(s):  
Temperature Change ◽  
Gas Diffusion ◽  
Measured Temperature ◽  
Desorption Process ◽  
Temperature Changes ◽  
Coal Gas ◽  
Coal Temperature ◽  
Gas Desorption ◽  
Heat Adsorption ◽  
Methane Desorption

To further reveal the mechanism of coal gas migration, the reasons for coal temperature changes during the methane desorption process were analyzed from the aspect of molecular motion and the thermodynamic theory. The temperature change mechanism was investigated, and the mathematical equation was established to describe the variation of temperature change during the methane desorption and diffusion process. The established equation was applied for the calculation of temperature change for two types of coal samples, and the measured and theoretical values of temperature changes were obtained. The results show that the temperature changes in the coal gas desorption process are mainly caused by the heat adsorption. The heat adsorption phenomenon was also caused by free gas expansion during the pressure relief process. The gas diffusion and work done for gas seepage also need heat adsorption. The temperature change is positively correlated to the coal gas pressure, quantity, and limit value of gas desorption volume. Due to the poor insulation in the test system, the difference between the theoretical and the measured temperature change values increase with the adsorption equilibrium pressure. It is helpful to further reveal the mechanism of coal and gas outburst. It also has an important reference value for controlling gas dynamic disasters in coal mines.

Variations of the Specimen Temperature Depending on the Pattern of the Multiaxial Load – Preliminary Research

2012 ◽  
Vol 726 ◽  
pp. 162-168 ◽  
Author(s):  
Adam Lipski ◽  
Dariusz Skibicki
Keyword(s):  
Plastic Strain ◽  
Normal Stress ◽  
Temperature Change ◽  
Infrared Thermography ◽  
Strain Energy ◽  
Temperature Changes ◽  
Average Temperature ◽  
Specimen Temperature ◽  
Preliminary Research ◽  
Plastic Strain Energy

This paper provides the results of research on temperature changes of cylindrical specimens depending on the pattern of the multiaxial load. The research were made by using passive infrared thermography. It was found out that the average temperature value is significantly dependent on the plastic strain energy and that the temperature change amplitude depends on the nominal normal stress (except for torsion).

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