Temperature effects on strength and deformation behaviour of rocks in Southern Ontario

1982 ◽  
Vol 19 (3) ◽  
pp. 307-319 ◽  
Author(s):  
Raymond S. C. Wai ◽  
K. Y. Lo
Keyword(s):  
Deformation Behaviour ◽  
Deformation Modulus ◽  
Temperature History ◽  
Granitic Gneiss ◽  
Experimental Procedure ◽  
Deformation Properties ◽  
History Of ◽  
Strength And Deformation ◽  
Effects Of Temperature ◽  
Increasing Temperature

A laboratory program to study the effects of temperature up to 350 °C on the strength and deformation properties of rocks was carried out. Particular attention was paid to the experimental procedure to avoid premature thermal cracking of the specimens. It was shown that the thermal–mechanical behaviour varies with the rock type. For granitic gneiss, the deformation modulus increases slightly with temperature up to 120 °C, then decreases at a rate of about 25% per 100 °C. Poisson's ratio generally decreases with increasing temperature up to 250 °C. The uniaxial compressive strength of granitic gneiss decreases with increasing temperature at a rate of the order of 30 MPa per 100 °C. The deformation properties of the granitic gneiss are also dependent on the temperature history of the specimen.In contrast, both the deformation and strength behaviour of the limestone appear to be insensitive to temperature change.

Investigation of the adhesion strength and deformation behaviour of in situ fabricated NbC coatings by scratch testing

2016 ◽  
Vol 299 ◽  
pp. 135-142 ◽  
Author(s):  
Xiaolong Cai ◽  
Yunhua Xu ◽  
Nana Zhao ◽  
Lisheng Zhong ◽  
Ziyuan Zhao ◽  
...  
Keyword(s):  
Adhesion Strength ◽  
Deformation Behaviour ◽  
Scratch Testing ◽  
Strength And Deformation

Constitutive Equations for the Thermomechanical Response of Rene´ 80: Part 2—Effects of Temperature History

1993 ◽  
Vol 115 (4) ◽  
pp. 358-364 ◽  
Author(s):  
V. S. Bhattachar ◽  
D. C. Stouffer
Keyword(s):  
Constitutive Equations ◽  
Temperature History ◽  
Nickel Base Superalloy ◽  
State Variable ◽  
History Effects ◽  
Variable Approach ◽  
Effects Of Temperature ◽  
Nickel Base ◽  
Nonisothermal Conditions ◽  
Base Superalloy

The unified constitutive equations for Rene´ 80 developed by Bhattachar and Stouffer (1992) are used to predict the thermomechanical fatigue (TMF) response of a Nickel base superalloy Rene´ 80 between 649°C and 1093°C. Predictions using these equations suggest that temperature history effects are significant during TMF, and that the TMF response of Rene´ 80 cannot be predicted completely using only isothermal parameters. It is postulated without metallurgical observations that the two deformation mechanisms in Rene´ 80, planar slip at low temperatures and dislocation climb at high temperatures, produce characteristic microstructures which interact under nonisothermal conditions to produce extra hardening that is not present during isothermal deformation. A state variable approach has been used to model this interaction. The nonisothermal model with temperature history effects could successfully predict the initial and saturated TMF response, and block isothermal response of Rene´ 80 from several tests between 649°C and 1093°C.

Survival of Endocronartium harknessii teliospores in a simulated airborne state

1989 ◽  
Vol 67 (3) ◽  
pp. 928-932 ◽  
Author(s):  
Kan-Fa Chang ◽  
P. V. Blenis
Keyword(s):  
Relative Humidity ◽  
Liquid Nitrogen ◽  
Long Distance ◽  
Spider Webs ◽  
Considerable Potential ◽  
Good Ability ◽  
Endocronartium Harknessii ◽  
Spore Longevity ◽  
Effects Of Temperature ◽  
Increasing Temperature

The effects of temperature and relative humidity (RH) on the survival of Endocronartium harknessii teliospores and the longevity of these spores out of doors during daylight hours were studied. In one experiment, fresh and liquid-nitrogen-stored spores of E. harknessii were impacted onto spider webs or plastic threads and incubated in darkness at temperatures of 6, 15, and 24 °C and RHs of 39 and 98%. Survival was measured after 1, 2, 4, 8, and 16 days. Spore longevity decreased with increasing temperature and was lower at 98 than at 39% RH. In a second experiment, spores were impacted onto spider webs and placed out of doors on clear days. Viability decreased linearly with time and averaged 33% after 12 h. The data suggest that E. harknessii has relatively good ability to survive in an airborne state and thus would have considerable potential for long distance spread.

The mechanical behavior of the Kettle Point oil shale

1986 ◽  
Vol 23 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Maurice B. Dusseault ◽  
Matthias Loftsson ◽  
David Russell
Keyword(s):  
Oil Shale ◽  
Clay Content ◽  
Organic Content ◽  
Point Load ◽  
Brazilian Test ◽  
Point Load Strength ◽  
Triaxial Strength ◽  
Deformation Properties ◽  
Strength And Deformation ◽  
Oil Shales

Samples of eastern black shale (Kettle Point oil shales, Ontario) were subjected to extensive mineralogical and geomechanical tests. We prove that the mineralogy, as measured by the ratio of quartz to illite, controls strength and deformation properties, and the organic material plays no significant role. The reason is that increasing clay content dilutes the rigid quartz–quartz grain contacts that are responsible for the high strengths and stiff behavior. Tests of temperature effects on point load strength of another low organic content oil shale confirm that organic matter is not important to mechanical properties in matrix-supported shales. Key words: shale, mineralogy, Brazilian test, triaxial strength, organic content, slake durability, thermogravimetry.

Effects of Temperature on Leaf Expansion in Sunflower

1982 ◽  
Vol 9 (2) ◽  
pp. 209 ◽  
Author(s):  
HM Rawson ◽  
JH Hindmarsh
Keyword(s):  
Field Studies ◽  
Leaf Expansion ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Leaf Position ◽  
Leaf Emergence ◽  
Temperature Regimes ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
Relative Change

Five commercial cultivars of sunflower were grown in cabinets at three temperature regimes, 32/22, 27/17 and 22/12°C, and with 15-h and 11-h photoperiods, and expansion of leaves 5-15 was followed. Leaves appeared faster with increasing temperature (0.022 leaves day-1 °C-1) and with increasing daylength. Areas of individual leaves increased linearly up the plant profile and, although final area per leaf (Amax) decreased with increasing temperature, the relative change was similar for each leaf position. Cultivars maintained their ranking for Amax across temperatures, and these rankings agreed with those in previous field studies. Within each temperature regime, both the expansion rate of leaves and the duration of expansion increased with leaf position. As temperature increased, leaves grew for shorter periods with a change of 1.04 days °C-1, but under the photon flux density used (500 �mol m-2 s-1, or about 25% full sunlight) expansion rates were greatest at the lowest temperature. Expansion rates were only one-third of those in field studies at comparable temperatures, but durations were similar. Cultivars that achieved the largest Amax did so via faster rates of expansion and not via longer durations: only one cultivar differed from the mean (20 days) duration of leaf expansion. All cultivars reached floral initiation progressively earlier with extension of photoperiod from 10 to 15 h, with the change for the most sensitive cultivars being 8 days and for the least sensitive 5 days. Rates of leaf emergence were linked with this sensitivity.

Shear connection between precast concrete bridge segments built with thin-walled elements

2021 ◽  
Author(s):  
Tobias Huber ◽  
Stephan Fasching ◽  
Johann Kollegger
Keyword(s):  
Precast Concrete ◽  
Deformation Behaviour ◽  
Lateral Force ◽  
Test Results ◽  
Construction Time ◽  
Shear Connection ◽  
Force Transfer ◽  
Strength And Deformation ◽  
Thin Walled ◽  
Segmental Bridge

<p>Segmental bridge construction combines the advantages of prefabrication, for example the reduction of construction time and very high product quality, with those of common bridge erecting methods. Short precast segments are assembled and prestressed to form the complete superstructure. New methods divide these segments into prefabricated elements to create new lighter versions of the segments. For this to work, new joint types must be developed which can ensure the force transfer between the segments. In this paper, several methods, including a new concept for joining thin-walled pre-fabricated elements, are described. Push-off tests with a constant lateral force were carried out to assess the shear strength and deformation behaviour. The main parameters were the joint type (wet joints: plain, grooved, keyed; dry joints), the mortar type, and the level of lateral force. In this paper, the test results are presented and recalculations with a design code are shown.</p>

Spatially and Temporally Resolved Temperature Measurements for Slow Evaporating Sessile Drops Heated by a Microfabricated Heater Array

2006 ◽  
Vol 129 (8) ◽  
pp. 966-976 ◽  
Author(s):  
S. W. Paik ◽  
K. D. Kihm ◽  
S. P. Lee ◽  
D. M. Pratt
Keyword(s):  
Contact Surface ◽  
Temperature Sensor ◽  
Water Droplet ◽  
Linear Array ◽  
Temperature History ◽  
Initial Contact ◽  
Constant Voltage ◽  
Radial Temperature ◽  
Spatially Resolved ◽  
History Of

The spatially and temporally resolved evaporation phenomena of a slowly evaporating water droplet are investigated using a microfabricated gold heater array consisting of 32 linear heater elements (100 μm wide and 15 mm long, each). Each of the gold microheater elements works both as a temperature sensor and as a heater. The experiment is performed under a constant voltage mode to examine the spatially resolved temperature history of the droplet contact surface for a period starting at initial contact with the heater and lasting to the point of complete dryout. The raw data obtained from the linear array have been tomographically deconvolved so that the radial temperature profile can be determined assuming a circular droplet contact surface.

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