Temperature Effects on the Seed-Germination of 10 Kwongan Species From Eneabba, Western-Australia

1990 ◽  
Vol 38 (5) ◽  
pp. 451 ◽  
Author(s):  
SM Bellairs ◽  
DT Bell
Keyword(s):  
High Temperature ◽  
Seed Germination ◽  
Western Australia ◽  
Low Temperatures ◽  
Temperature Effects ◽  
Perennial Species ◽  
Wetting And Drying ◽  
High And Low Temperatures ◽  
Western Australian

The germination responses of 10 species (Acacia blakelyi, A. pulchella, Allocasuarina humilis, Beaufortia elegans, Conostylis neocymosa, Eucalyptus tetragona, Kennedia prostrata, Leptospermum spinescens, Melaleuca acerosa and Xanthorrhoea drummondii) to constant temperatures ranging from 5 to 35� C were studied. These Western Australian perennial species had optimum germination percentages between 15 and 20�C, except Eucalyptus tetragona which had an optimum at 25�C and Leptospermum spinescens which had an optimum at 10�C. Seeds were transferred from high and low temperatures to 15�C to determine whether high or low temperatures induced dormancy. Low temperatures tended not to affect subsequent germination but high temperature decreased subsequent germination for some species. Wetting and drying stimulated the germination of Acacia blakelyi, A. pulchella and Kennedia prostrata seeds.

Relieving of Residual Stresses in Metal Workpieces at High and Low Temperatures

2021 ◽  
Vol 887 ◽  
pp. 651-656
Author(s):  
Marina V. Polonik
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Residual Stresses ◽  
Low Temperatures ◽  
Creep Properties ◽  
Processing Modes ◽  
Properties Of Materials ◽  
High And Low Temperatures ◽  
Temperature Heating ◽  
High Temperature Heating

On the basis of previously accumulated irreversible deformations, and, consequently, residual stresses, the process of removing residual stresses in metal workpieces under the action of low and high temperatures is simulated. Boundary value problems are solved and here are described regularities that are responsible for removing residual stresses for processing modes: high-temperature heating - cooling, high-temperature heating - holding - cooling, low-temperature heating - holding - cooling. The holding stage is modeled, taking into account the creep properties of materials under Norton creep conditions. According to the dependences of the obtained exact solutions, it is shown that it is the holding process that leads to the relaxation of residual stresses.

Western Australian Species-Rich Kwongan (Sclerophyllous Shrubland) Affected by Drought

1980 ◽  
Vol 28 (6) ◽  
pp. 573 ◽  
Author(s):  
RJ Hnatiuk ◽  
AJM Hopkins
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Western Australia ◽  
Vascular Plants ◽  
Perennial Species ◽  
Australian Species ◽  
Vegetative Regeneration ◽  
Average Rainfall ◽  
Two Factors ◽  
Western Australian

Observations of responses to aseasonal water stress are reported for 238 above-ground perennial species of native vascular plants in a 20 km2 area of Western Australia surveyed during the second consecutive year of below average rainfall. Eighty-six species (36%) were found with dead individuals. Both vegetative regeneration and seedling regeneration appeared to be successful means of surviving drought stress in this region. The drought affected species of the families Proteaceae and Epacridaceae more than those of other major families. There are similarities in the response of the vegetation to the two main, irregularly occurring phenomena, aseasonal drought and fire: both can affect vegetation over large areas and yet leave considerable patches within the area that are little affected. Together these two factors contribute to the production of complex and dynamic mosaic-patterns in the vegetation.

Peotoemission Study of Si (001) Surfaces Exposed to as Flux

1989 ◽  
Vol 148 ◽  
Author(s):  
H. Okumura ◽  
K. Miki ◽  
K. Sakamoto ◽  
T. Sakamoto ◽  
S. Misawa ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Temperature Dependence ◽  
Electronic Structures ◽  
Low Temperatures ◽  
Dimer Model ◽  
Surface And Interface ◽  
High And Low Temperatures ◽  
Interface Structures ◽  
Temperature Sample

ABSTRACTPhotoemission spectra (XPS and UPS) of As-covered Si (001) surfaces prepared at high (>600ºC) and low (<450ºC) temperatures and GaAs epilayers subsequently grown on them were measured without exposing to air. It was found that the surface electronic structures of As/Si prepared at the low temperature are different from those of the high temperature sample, the spectra of which can be interpreted as a symmetric dimer model. Differences were also observed between the GaAs epilayers on the As—covered Si surfaces prepared at the high and low temperatures. The temperature dependence of the surface and interface structures are discussed.

N-A-X AC9115

Alloy Digest ◽  
1953 ◽  
Vol 2 (8) ◽  
Keyword(s):  
High Temperature ◽  
Great Lakes ◽  
Low Temperatures ◽  
Gas Turbines ◽  
Heat Treating ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Temperature Performance ◽  
Before And After ◽  
High And Low Temperatures

Abstract N-A-X AC 9115 is a low-carbon low-alloy steel having good strength, toughness, and stability before and after welding, at both high and low temperatures. It is recommended for use in gas turbines and allied applications. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SA-11. Producer or source: Great Lakes Steel Corporation.

scholarly journals Environmental tests of vapor compression heat pump for space applications

2020 ◽  
pp. 240-240
Author(s):  
Xudong Ma ◽  
Rui Ma ◽  
Yilin Ye ◽  
Suying Yan ◽  
Feng Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Heat Pump ◽  
Low Temperatures ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Space Applications ◽  
Suitable Temperature ◽  
High And Low Temperatures

Heat pumps are needed to provide a suitable temperature for both people and equipment in spacecraft. This paper reports on work designed to see if vapor compression heat pumps, in particular, can be expected to function normally in space. A vapor compression heat pump was built and tested under conditions of high temperature (70?C), low temperature (0?C), and near-vacuum (10-4 Pa). It was found that the coefficient of performance of this heat pump was 2.99 at both high and low temperatures, and was 2.1 under near vacuum conditions. The results suggest that vapor compression heat pumps are suitable for use in space.

scholarly journals 835 PB 349 HIGH-TEMPERATURE EFFECTS ON SOLUBLE OLIGOSACCHARIDE LEVELS IN SPINACH SEEDS DURING IMBIBITION AND GERMINATION

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 552g-553
Author(s):  
Virgil Esensce ◽  
Daniel I. Leskovar
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Low Temperatures ◽  
Temperature Effects ◽  
Spinacia Oleracea ◽  
Membrane Stabilization ◽  
Similar Role ◽  
Glucose Levels ◽  
Higher Temperature

Spinach (Spinacia oleracea, L. cv. `Ark88-354'. `Fall Green', `Cascade') seeds of varying sensitivities to high temperatures during imbibition and germination were subjected to constant 18, 30 and 36°C for 96 hours during imbibition. Those cultivars less sensitive to high temperatures (`Ark88-354' and `Fall Green') imbibed water more rapidly at higher temperatures and had greater initial levels of raffinose and sucrose than the sensitive cultivar `Cascade'. Glucose levels were initially zero in all cultivars and increased slightly with time. Germination was more rapid at 18°C and 30°C in `Ark88-354' and `Fall Green' than with `Cascade'; the latter also failed 10 germinate at the higher temperature. Raffinose and sucrose have been implicated in membrane stabilization during desiccation and extreme low temperatures. They may serve a similar role during imbibition and germination of spinach at high temperatures, reducing secondary thermodormancy.

scholarly journals High and Low Temperatures Differently Affect Infection Density and Vertical Transmission of Male-Killing Spiroplasma Symbionts in Drosophila Hosts

2008 ◽  
Vol 74 (19) ◽  
pp. 6053-6059 ◽  
Author(s):  
Hisashi Anbutsu ◽  
Shunsuke Goto ◽  
Takema Fukatsu
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Vertical Transmission ◽  
Low Temperatures ◽  
Environment Interaction ◽  
Host Genotype ◽  
Male Killing ◽  
Infection Density ◽  
High And Low Temperatures ◽  
Native Host

ABSTRACT We investigated the vertical transmission, reproductive phenotype, and infection density of a male-killing Spiroplasma symbiont in two Drosophila species under physiological high and low temperatures through successive host generations. In both the native host Drosophila nebulosa and the nonnative host Drosophila melanogaster, the symbiont infection and the male-killing phenotype were stably maintained at 25�C, rapidly lost at 18�C, and gradually lost at 28�C. In the nonnative host, both the high and low temperatures significantly suppressed the infection density of the spiroplasma. In the native host, by contrast, the low temperature suppressed the infection density of the spiroplasma whereas the high temperature had little effect on the infection density. These results suggested that the low temperature suppresses both the infection density and the vertical transmission of the spiroplasma whereas the high temperature suppresses the vertical transmission preferentially. The spiroplasma density was consistently higher in the native host than in the nonnative host, suggesting that the host genotype may affect the infection density of the symbiont. The temperature- and genotype-dependent instability of the symbiont infection highlights a complex genotype-by-genotype-by-environment interaction and may be relevant to the low infection frequencies of the male-killing spiroplasmas in natural Drosophila populations.

Thermodynamic Performance Analysis of Ammonia-Water Rankine Cycles Using Heat Sources of High and Low Temperatures

2012 ◽  
Vol 249-250 ◽  
pp. 278-283
Author(s):  
Kyoung Hoon Kim ◽  
Hyung Jong Ko ◽  
Se Woong Kim
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Thermal Efficiency ◽  
Low Temperatures ◽  
Ammonia Concentration ◽  
Working Fluid ◽  
Heat Sources ◽  
Ammonia Water ◽  
High And Low Temperatures ◽  
System Variables

In this study, thermodynamic performances of ammonia-water Rankine (AWR) cycle and regenerative Rankine (AWRR) cycle are comparatively investigated. Special attention is focused on the effects of ammonia concentration and turbine inlet pressure on the performance of system using heat sources of high temperature of 300 oC and low temperature of 150 oC. The behavior of important system variables including mass flow ratio of working fluid, net work production, and thermal efficiency are closely examined. Results show that performance characteristics for heat sources of high and low temperatures are quite different each other. For the high-temperature source, the thermal efficiency has a minimum in AWR system while it has a maximum in AWRR with respect to ammonia concentration in the range of 65% to 75%. For low-temperature source, however, the thermal efficiency decreases with ammonia concentration in the range of ammonia concentration higher than 95% for both AWR system and AWRR system and the effect of regenerator is negligible.

Seed ageing of four Western Australian species in relation to storage environment and seed antioxidant activity

2003 ◽  
Vol 13 (2) ◽  
pp. 155-165 ◽  
Author(s):  
D.J. Merritt ◽  
T. Senaratna ◽  
D.H. Touchell ◽  
K.W. Dixon ◽  
K. Sivasithamparam
Keyword(s):  
Antioxidant Activity ◽  
Seed Germination ◽  
Relative Humidity ◽  
Western Australia ◽  
Seed Viability ◽  
Seedling Vigour ◽  
Australian Species ◽  
Seed Ageing ◽  
Western Australian ◽  
Water Contents

AbstractThe influence of the storage environment on seed viability and antioxidant potential was examined for four species native to Western Australia: Acacia bivenosa DC., Anigozanthos manglesii D. Don, Banksia ashbyi E.G. Baker, and Mesomelaena tetragona (R. Br.) Benth. Seeds were stored at four water contents (at c. 5%, 11–15%, 20–23% and 50% relative humidity) at each of five temperatures (–196, –18, 5, 23 and 50°C), and seed germination and seedling vigour monitored over an 18-month period. Deterioration was apparent in all species (except A. bivenosa) stored at 50°C, with 11% RH maximizing longevity for B. ashbyi and M. tetragona seeds, and 5% or 11% RH preventing deterioration for A. manglesii seeds. Seed viability generally remained high for all species stored at 23°C or less. Notably, however, germination and seedling vigour of A. manglesii and M. tetragona seeds gradually declined when stored at –18°C, suggesting that storage at this temperature was detrimental. The antioxidant activity of lipid extracts of seeds after 18 months storage at 5, 23 and 50°C was also examined to determine whether the seed viability decline was associated with a loss of antioxidants. Antioxidant activity varied between storage treatments and was not related to seed viability.

Temperature effects on germination of Trifolium balansae and T. resupinatum with special reference to high-temperature dormancy

1994 ◽  
Vol 45 (3) ◽  
pp. 689 ◽  
Author(s):  
PI Jansen ◽  
RL Ison
Keyword(s):  
High Temperature ◽  
Special Reference ◽  
Western Australia ◽  
Temperature Effects ◽  
Seed Weight ◽  
South Australia ◽  
Plant Introduction ◽  
Effect Of Temperature ◽  
Pasture Legumes ◽  
Thousand Seed Weight

The effect of temperature on germination of the annual pasture legumes Trifolium balansae and T. resupinaturn was investigated. Seed of T. resupinatum lines SA 12240, SA 14433 (from South Australia), C1Z1Res-B, CPI (Commonwealth Plant Introduction number) 026202-3, CPI 026205-2, CPI 027376-2, SA 14433 (from Western Australia), SA 18904, SA 18922, SA 19851 and CPI 045887-2 and cvv. Kyambro and Maral and T. balansae cv. Paradana and lines CPI 045856-1, CPI 045856-4 and AZ 2326 was germinated at 10, 15, 20, 25, 30 and 35�C. T. subterraneum cv. Junee was included for comparison. It was found that germination in all lines except Maral was reduced at 35�C, whereas at 30�C germination was reduced significantly in all lines except Maral, ClZlRes-B, CPI 026202-3, CPI 026205-2, CPI 027376-2, SA 19851 and CPI 045887-2. Germination at 35OC in T. resupinaturn was related to thousand seed weight with the equation: Germination = -31.19+92-39 thousand seed weight (r2 = 0.76). In order to determine the mechanism responsible for the failure of seed to germinate at temperatures above 25�C, seed of T. resupinatum lines SA 12240 and SA 14433 and Maral and T. balansae cv. Paradana was allowed to germinate at temperatures of 25, 30, 35, 40, 45 and 50�C for 8 h, 1, 2, 5 and 10 days after which they were placed at 15� C for 10 days. It was found that temperatures in the 30-40�C temperature range inhibited germination in all lines except Maral, but the same seed germinated readily when placed at 15�C. This seed was considered to possess an enforced high-temperature dormancy. Seed of all lines exposed to 45 and 50�C for longer than 8 h died, but at 8 h final germination was unaffected. It was concluded that high-temperature dormancy could play a role in preventing seed from germinating in the case of a false break. It was proposed that lines should be screened for high-temperature dormancy.

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