Swelling of Constrained Rubber Layers: Effect on Free Energy of Detachment

2001 ◽  
Vol 74 (1) ◽  
pp. 89-99
Author(s):  
A. N. Gent ◽  
W. J. Hung ◽  
M. F. Tse
Keyword(s):  
Bond Rupture ◽  
Stored Energy ◽  
Rigid Substrate ◽  
Representative Case ◽  
Rubber Layer ◽  
Available Energy ◽  
Degree Of Swelling ◽  
Theoretical Predictions ◽  
Released Energy ◽  
Intrinsic Strength

Abstract The degree of swelling of a rubber layer by a compatible liquid has been calculated for cases when the layer is constrained, for example when it is bonded to a rigid substrate. The stored energy residing in swollen layers is also computed. From these results the amount of energy is determined that becomes available if a bonded layer separates from a substrate and then becomes free to swell further. The released energy is shown to be quite high, of the order of 10 MJ/m3 in a representative case. Attention is drawn to the importance of the layer thickness when this energy is applied to bond rupture. For layers having a thickness of the order of 1 mm or greater, the available energy is greater than the intrinsic strength of the bond or of the swollen elastomer itself. In accord with this conclusion, soft rubber layers, sandwiched between and bonded to flexible but inextensible backings, are observed to separate spontaneously and then tear away from the backing when swollen by a compatible liquid. And layers that are still attached to the backing become sharply curved before tearing loose, in rough agreement with the theoretical predictions.

scholarly journals Initial effective stress controls the nature of earthquakes

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
François X. Passelègue ◽  
Michelle Almakari ◽  
Pierre Dublanchet ◽  
Fabian Barras ◽  
Jérôme Fortin ◽  
...  
Keyword(s):  
Effective Stress ◽  
Physical Mechanism ◽  
Fluid Pressure ◽  
Fault Slip ◽  
Rupture Velocity ◽  
Complete Spectrum ◽  
Available Energy ◽  
Different Types ◽  
Theoretical Predictions ◽  
Shallow Part

Abstract Modern geophysics highlights that the slip behaviour response of faults is variable in space and time and can result in slow or fast ruptures. However, the origin of this variation of the rupture velocity in nature as well as the physics behind it is still debated. Here, we first highlight how the different types of fault slip observed in nature appear to stem from the same physical mechanism. Second, we reproduce at the scale of the laboratory the complete spectrum of rupture velocities observed in nature. Our results show that the rupture velocity can range from a few millimetres to kilometres per second, depending on the available energy at the onset of slip, in agreement with theoretical predictions. This combined set of observations bring a new explanation of the dominance of slow rupture fronts in the shallow part of the crust or in areas suspected to present large fluid pressure.

scholarly journals Utilisation of JSI TRIGA Pulse Experiments for Testing of Nuclear Instrumentation and Validation of Transient Models

2020 ◽  
Vol 225 ◽  
pp. 04027 ◽  
Author(s):  
Ingrid Vavtar ◽  
Anže Pungerčič ◽  
Luka Snoj
Keyword(s):  
Physical Parameters ◽  
Full Width ◽  
Half Maximum ◽  
Maximal Power ◽  
Pulse Experiment ◽  
Theoretical Predictions ◽  
Released Energy ◽  
Transient Models ◽  
Nuclear Instrumentation

A pulse experiment model was validated in order to support future pulse experimental campaigns. All pulse experiments data was collected and are publicly available at http://trigapulse.ijs.si/. A comparison of the measured pulse physical parameters (maximal power, total released energy and full width at half maximum) and theoretical predictions (Fuchs-Hansen and the Nordheim-Fuchs models) was made.

Performance Analysis of a V2G Brokering Agent

2014 ◽  
Vol 686 ◽  
pp. 634-638 ◽  
Author(s):  
Jung Hoon Lee ◽  
Ji Hyun Kang
Keyword(s):  
Search Space ◽  
Stored Energy ◽  
Demand And Supply ◽  
Vehicle To Grid ◽  
Consumption Ratio ◽  
Available Energy ◽  
Power Load ◽  
Stay Time ◽  
Temporal And Spatial ◽  
The Given

This paper first presents a brokering architecture for a vehicle-to-grid electricity trades between electric vehicles and a microgrid, and then measures its performance, particularly focusing on the stay time, which significantly affects the scheduling flexibility. The brokering service matches demand and supply on battery-stored energy, traversing the search space to find an energy allocation for each time slot. The slot-by-slot schedule, generated from the two-way interaction protocol, coordinates the arrival time of each seller at the microgrid, achieving temporal and spatial power load shift. The performance measurement based on a prototype implementation analyzes the effect on the lacking and surplus energy, the demand meet ratio, and the effective consumption ratio. The experiment result shows that the brokering scheme can fully take advantage of enhanced flexibility in placing available energy on the time slots, reducing the lacking amount by up to 38.4 % as well as enhancing the consumption ratio by up to 27 % for the given parameter set.

Sliding Resistance on a Constrained Rubber Layer Due to Rubber Hysteresis

2000 ◽  
Vol 73 (2) ◽  
pp. 217-224
Author(s):  
C. G. Li ◽  
P. S. Steif
Keyword(s):  
Universal Design ◽  
Rolling Resistance ◽  
Design Tool ◽  
Constitutive Law ◽  
Rubber Layer ◽  
New Class ◽  
Dependent Behavior ◽  
Theoretical Predictions ◽  
Filled Rubbers ◽  
Sliding Resistance

Abstract Sliding resistance of a rigid cylinder over a thin rubber layer due to rubber hysteresis is investigated. This problem underlies a model being developed for quantitatively accurate predictions of the performance of a new class of damping devices. As a full multiaxial constitutive law reflecting the amplitude-dependent behavior of filled rubbers is not available, this paper sets forth an approximate method of analysis which indirectly accounts for the material nonlinearity. Results of extensive finite element calculations are then reduced to compact material-independent forms which can be used as a universal design tool. Measurements of rolling resistance are also compared with theoretical predictions.

scholarly journals Physical Condition of an Animal, Using as an Example the Common Eider, Somateria mollissima

2003 ◽  
Vol 117 (2) ◽  
pp. 230 ◽  
Author(s):  
Arnaud J. Cabanac
Keyword(s):  
Physical Condition ◽  
Somateria Mollissima ◽  
Energy Reserves ◽  
Stored Energy ◽  
Survival Chance ◽  
Available Energy ◽  
Common Eiders ◽  
The Subject ◽  
The Common ◽  
Time Of Year

An index of the physical condition of an animal should describe its endogenous available energy. The welfare of the animal depends on its ability to spend its stored energy (lipid and protein) in order to survive the environmental and behavioural challenge at the particular time of its capture. I propose a new index to predict the survival chance of the subject. The new index of physical condition takes into account the available endogenous energy reserves and the known needs of the species at that particular time of year. I further illustrate this new method of estimating the physical condition by running a trial with Common Eiders, Somateria mollissima.

Stiffness and Bond Strength of Rubber-Filled Hinges

1993 ◽  
Vol 66 (5) ◽  
pp. 733-741 ◽  
Author(s):  
A. N. Gent ◽  
Y-W. Chang
Keyword(s):  
Finite Element Analysis ◽  
Bond Strength ◽  
Direct Analysis ◽  
Test Method ◽  
Bond Rupture ◽  
Experimental Measurements ◽  
Element Analysis ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Good Agreement

Abstract The stiffness of rubber-filled hinges for small rotations of the hinge plates has been determined by finite element analysis (FEA). The rubber is assumed to be linearly elastic and virtually incompressible, and the hinge is assumed to be long enough for the rubber to be in a state of plane strain, i.e., prevented from any displacement parallel to the hinge. Results have been obtained for hinges of a wide range of unstrained angle, ranging from 5° up to 360°. The calculated stiffnesses for long hinges vary by over four orders of magnitude over this range. For small angles, an approximate solution has been obtained by direct analysis—it is in good agreement with the FEA solution for hinge angles up to about 40°. Experimental measurements on several rubber-filled hinges are also reported. The measured rotational stiffnesses are in satisfactory agreement with theoretical predictions. Because a rubber-filled hinge constitutes a possible test method for bond strength, conditions are derived for bond rupture as a hinge is strained open.

The Role of Ballistic, Electronic, and Thermal Processes in Electron Irradiation Damage of Maximum Valence Transition Metal Oxide Surfaces

1991 ◽  
Vol 235 ◽  
Author(s):  
M. I. Buckett ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Transition Metal Oxides ◽  
Structural Changes ◽  
High Resolution Electron Microscopy ◽  
Incident Electron Energy ◽  
Irradiation Damage ◽  
Experimental Conditions ◽  
Valence Transition ◽  
Available Energy ◽  
Theoretical Predictions

ABSTRACTSurface-initiated radiation damage processes in a number of the maximum valence transition metal oxides - TiO2, V2O5, WO3, MoO3, Ta2O5, Al2O3, and Nb2O5 - have been investigated by in-situ high resolution electron microscopy under UHV conditions and at incident energies ranging from 3 keV to 300 keV. The relative contributions of ballistic, electronic, and thermal effects are evaluated by a comparison of the observed structural changes and damage rates - made under various experimental conditions of incident electron energy and flux - to theoretical predictions based on thermodynamic and available energy criteria.

Phase Field Study of Second Phase Particles-Pinning on Strain Induced Grain Boundary Migration

2020 ◽  
Vol 993 ◽  
pp. 967-975
Author(s):  
Kai Li ◽  
Yao Shen ◽  
Da Yong Li ◽  
Ying Hong Peng
Keyword(s):  
Grain Boundary ◽  
Phase Field ◽  
Boundary Migration ◽  
Phase Field Model ◽  
Energy Difference ◽  
Second Phase ◽  
Grain Boundary Migration ◽  
Stored Energy ◽  
Second Phase Particles ◽  
Theoretical Predictions

A phase field model was presented to investigate the effect of particles-pinning on grain boundary migration in materials containing stored energy differences across the grain boundaries. The accuracy of the phase field framework was examined by comparing the simulated results with theoretical predictions. The pinning effects of coherent and non-coherent second phase particles on the boundary migration were studied in triple-grain models. 2D simulations with second phase particles of different sizes or different area fractions were performed. The effect of stored energy difference across the boundary on the particles-pinning was also investigated. The results showed that the pinning effect could be enhanced by the decrement of the particle size and the increment of particle area fraction. Increasing the stored energy difference across the grain boundary induced higher grain boundary migration velocity and weaker particles-pinning.

An investigation on the microstructure and defects in the mechanically milled Cu and Fe powders

2014 ◽  
Vol 30 (1) ◽  
pp. 14-24
Author(s):  
M. Mojtahedi ◽  
M. Goodarzi ◽  
M. R. Aboutalebi ◽  
V. Soleimanian
Keyword(s):  
Three Dimensional ◽  
Geometrical Approach ◽  
Stored Energy ◽  
Line Broadening ◽  
Scanning Calorimetry ◽  
Microstructural Characteristics ◽  
X Ray ◽  
X Ray Crystallography ◽  
Geometrical Modelling ◽  
Released Energy

The microstructural characteristics of mechanically milled (MM) iron (Fe) and copper (Cu) powders are investigated by means of various X-ray crystallography analysis methods. The conventional Williamson–Hall and Warren–Averbach methods are used besides the modified Williamson–Hall, the modified Warren–Averbach, and the Variance approaches, in proper cases. Afterward, the obtained crystallite size and dislocation density are used to calculate the stored energy in the nanostructured powders. For this aim, a new geometrical approach is developed which can consider three-dimensional crystallites and the thickness of boundaries between them. Moreover, the released energy during annealing of MM Cu and Fe powders is measured using differential scanning calorimetry. The results of line broadening analysis and geometrical modelling are combined to the calorimetry of a room temperature aged Cu powder. In this way, the thickness of grain boundary in the nanostructured Cu is calculated to be 1.6 nm.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

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