Distal antebrachial fractures in toy-breed dogs
International Nuclear Information System (INIS)
Antebrachial fractures account for approximately 17% of all canine fractures, with motor vehicle trauma cited as one of the primary causes. However, antebrachial fractures in toy-breed dogs are often sustained after apparently minimal trauma, such as jumping or falling, and are usually distal. The cause of antebrachial fractures in toy breeds is not well understood. Complications after treatment of distal antebrachial fractures in toy-breed dogs, including delayed union, nonunion, and malunion, are common and are potentially serious because they may necessitate limb amputation. This article reports on distal antebrachial fractures in 26 toy-breed dogs that wee presented to the University of California, Davis, Veterinary Medical Teaching Hospital from April 1987 to March 1996. The author found that (1) these fractures typically occur in growing or adolescent dogs; (2) the presence of complications of union is typically associated with prior treatment using intramedullary pinning or external coaptation; and (3) successful healing of this type of fracture is obtained via rigid stabilization with bone plating in combination with cancellous bone autograft
Void growth and coalescence in metals deformed at elevated temperature
DEFF Research Database (Denmark)
Klöcker, H.; Tvergaard, Viggo
2000-01-01
For metals deformed at elevated temperatures the growth of voids to coalescence is studied numerically. The voids are assumed to be present from the beginning of deformation, and the rate of deformation considered is so high that void growth is dominated by power law creep of the material, without...... voids. The focus of the study is on various relatively high stress triaxialties. In order to represent the results in terms of a porous ductile material model a set of constitutive relations are used, which have been proposed for void growth in a material undergoing power law creep....
Fascial deformation in the lateral elbow region: A conceptual approach
R. Stoeckart (Rob); A. Vleeming (Andry); J.L. Simons; R.P. van Helvoirt (R.); C.J. Snijders (Chris)
1991-01-01
markdownabstractAbstract In embalmed preparations, the antebrachial fascia in the lateral elbow region is shown to be deformed by load application to the triceps muscle. From this fascia, muscles arise which are primarily concerned with the extension of wrist and fingers. In the case of lateral ep
Williams, Frank L'Engle; Cunningham, Deborah L; Amaral, Lia Q
2015-12-01
When hominin bipedality evolved, the forearms were free to adopt nonlocomotor tasks which may have resulted in changes to the articular surfaces of the ulna and the relative lengths of the forearm bones. Similarly, sex differences in forearm proportions may be more likely to emerge in bipeds than in the great apes given the locomotor constraints in Gorilla, Pan and Pongo. To test these assumptions, ulnar articular proportions and the antebrachial index (radius length/ulna length) in Homo sapiens (n=51), Gorilla gorilla (n=88), Pan troglodytes (n=49), Pongo pygmaeus (n=36) and Australopithecus afarensis A.L. 288-1 and A.L. 438-1 are compared. Intercept-adjusted ratios are used to control for size and minimize the effects of allometry. Canonical scores axes show that the proximally broad and elongated trochlear notch with respect to size in H. sapiens and A. afarensis is largely distinct from G. gorilla, P. troglodytes and P. pygmaeus. A cluster analysis of scaled ulnar articular dimensions groups H. sapiens males with A.L. 438-1 ulna length estimates, while one A.L. 288-1 ulna length estimate groups with Pan and another clusters most closely with H. sapiens, G. gorilla and A.L. 438-1. The relatively low antebrachial index characterizing H. sapiens and non-outlier estimates of A.L. 288-1 and A.L. 438-1 differs from those of the great apes. Unique sex differences in H. sapiens suggest a link between bipedality and forearm functional morphology. PMID:26256651
Konno, Toshihiro; Watanabe, Kouichi
2012-01-01
The antebrachium of domestic animals supports the trunk against gravity and generates propulsive force. The antigravity action of antebrachium is attributed to the contraction of flexor muscles of the carpal and digital joints. Mammalian skeletal muscles consist of myofibers, which are histochemically classified into type I, type IIA, and type IIB myofibers, of which composition reflects the proportional involvement of the muscle in varying function, such as posture maintenance and locomotion. The physiological cross-sectional area (PCSA), which are calculated from muscle volume, myofiber length, and pennation angle, reflects the maximum force of muscle. In the present study, we evaluated the PCSA of myofiber types in the antebrachial musculature and determined the magnitude of contribution from individual muscles toward varying actions of carpal and digital joints. The extensor carpi ulnaris and flexor digitorum superficialis muscles possessed a large proportional PCSA of type I myofibers, indicating the role for these muscles in maintaining a standing posture. The additional force required for walking/running was primarily provided by the flexor digitorum profundus caput humerale and extensor carpi radialis muscles. The proportional PCSA of myofiber types reflected the force generated for varying muscular function and provided insights into the dynamics of carpal and digital joints. PMID:23117305
Structural deformation of metallic uranium surrounding hydride growth sites
International Nuclear Information System (INIS)
Highlights: • UH3 formation on uranium surfaces by a controlled uptake of hydrogen at 240 °C. • Large hydride growths (35–125 μm in diameter) form at the surface. • Confined hydride expansion during growth generates stress in the subsurface. • EBSD scans found micro-cracking and twins as forms of stress relief in the metal. - Abstract: Electron backscatter diffraction (EBSD) was utilised to probe the microstructure of uranium metal in the vicinity of surface corrosion pits, resulting from hydrogen exposure (5 × 104 Pa, at 240 °C). Microstructural analysis of the surface revealed a subtle increase of grain orientation variation for grains at the border of the hydride growths. Cross sectional analysis, at pit sites, revealed significant microstructure deformation in the form of crystal twinning and micro-cracking beneath the surface. These observations provide qualitative evidence that local stress intensities generated as a consequence of hydride growth and confinement, were sufficient to cause deformation within the parent metal
Influence of deformation on dolomite rim growth kinetics
Helpa, Vanessa; Rybacki, Erik; Grafulha Morales, Luiz Fernando; Dresen, Georg
2015-04-01
Using a gas-deformation apparatus stacks of oriented calcite (CaCO3) and magnesite (MgCO3) single crystals were deformed at T = 750° C and P = 400 MPa to examine the influence of stress and strain on magnesio-calcite and dolomite (CaMg[CO3]2) growth kinetics. Triaxial compression and torsion tests performed at constant stresses between 7 and 38 MPa and test durations between 4 and 171 hours resulted in bulk strains of 0.03-0.2 and maximum shear strains of 0.8-5.6, respectively. The reaction rims consist of fine-grained (2-7 μm) dolomite with palisade-shaped grains growing into magnesite reactants and equiaxed granular dolomite grains next to calcite. In between dolomite and pure calcite, magnesio-calcite grains evolved with an average grain size of 20-40 μm. Grain boundaries tend to be straighter at high bulk strains and equilibrium angles at grain triple junctions are common within the magnesio-calcite layer. Transmission electron microscopy shows almost dislocation free palisades and increasing dislocation density within granular dolomite towards the magnesio-calcite boundary. Within magnesio-calcite grains, dislocations are concentrated at grain boundaries. Variation of time at fixed stress (˜17 MPa) yields a parabolic time dependence of dolomite rim width, indicating diffusion-controlled growth, similar to isostatic rim growth behavior. In contrast, the magnesio-calcite layer growth is enhanced compared to isostatic conditions. Triaxial compression at given time shows no significant change of dolomite rim thickness (11±2 μm) and width of magnesio-calcite layers (33±5 μm) with increasing stress. In torsion experiments, reaction layer thickness and grain size decrease from the center (low stress/strain) to the edge (high strain/stress) of samples. Chemical analysis shows nearly stoichiometric composition of dolomite palisades, but enhanced Ca content within granular grains, indicating local disequilibrium with magnesio-calcite, in particular for twisted
Medial antebrachial cutaneous nerve measurements to diagnose neurogenic thoracic outlet syndrome.
Machanic, Bennett I; Sanders, Richard J
2008-03-01
A reliable objective test is still needed to confirm the diagnosis of neurogenic thoracic outlet syndrome (NTOS). Over the past 20 years, it has been suggested that responses to medial antebrachial cutaneous nerve (MAC) and C8 nerve root stimulation could be used for this purpose. Herein, we explore this thesis. A clinical diagnosis of NTOS was established in 41 patients, all of whom underwent surgical decompression. Preoperatively, all patients were studied with MAC sensory neural action potential (SNAP) determinations and C8 nerve root stimulation. Controls were 19 asymptomatic, healthy volunteers. MAC sensory latency on 79 control sides was 1.5-2.4 msec, while latency in 41 symptomatic patients ranged 2.2-2.8 msec. Latency of 2.5 or greater was noted in 30 patients (specificity 99%, sensitivity 73%), confirming a diagnosis of NTOS, while the remaining 11 (27%) fell into the borderline zone of 2.2-2.4 msec. The latency difference between right and left sides in controls was 0-0.2 msec in 17 (89%), while in NTOS patients 31 had a difference of 0.3 msec or more (sensitivity 89%, specificity 63%). Amplitudes of 10 muV or more occurred in 77 of 79 control sides, whereas the amplitude was under 10 muV in 28 patients (specificity 97%, sensitivity 68%). Amplitude ratios between right and left sides in controls were 1.7 or less. Ratios of 2.0 or more were measured in 25 patients (specificity 100%, sensitivity 61%). Using the four diagnostic criteria (latency over 2.4 msec, latency difference between sides of 0.3 or more, amplitude under 10 muV, and amplitude ratios of 2.0 or more), 40 of the 41 patients had at least one of the four diagnostic criteria, 23 patients (56%) had three or four positive criteria, and 12 (29%) had two. C8 nerve root stimulation responses were below normal (56 M/sec) in 54%. MAC measurement is a fairly reliable technique for confirming the diagnosis of NTOS. Latency determination appeared to be a slightly more consistent measurement in this study
Raj, Baldev; Mukhopadhyay, C. K.; Jayakumar, T.
2003-03-01
Acoustic emission (AE) during tensile deformation and fatigue crack growth (FCG) of austenitic stainless steels has been studied. In AISI type 316 stainless steel (SS), AE has been used to detect micro plastic yielding occurring during macroscopic plastic deformation. In AISI type 304 SS, relation of AE with stress intensity factor and plastic zone size has been studied. In AISI type 316 SS, fatigue crack growth has been characterised using acoustic emission.
Guided growth for correction of knee flexion deformity: a series of four cases
MacWilliams, B. A.; Harjinder, B.; Stevens, P M
2011-01-01
Fixed knee flexion deformity can present as an insidious and significant problem in diverse etiologies, most commonly in cerebral palsy. Traditional surgical intervention has included posterior capsulotomy and supracondylar femoral osteotomy, both of which carry significant associated morbidity and risks. In the skeletally immature patient, guided growth may be used to correct or substantially diminish the deformity. We are presenting our early experience encompassing four subjects who comple...
Deformation and crack growth response under cyclic creep conditions
Energy Technology Data Exchange (ETDEWEB)
Brust, F.W. Jr. [Battelle Memorial Institute, Columbus, OH (United States)
1995-12-31
To increase energy efficiency, new plants must operate at higher and higher temperatures. Moreover, power generation equipment continues to age and is being used far beyond its intended original design life. Some recent failures which unfortunately occurred with serious consequences have clearly illustrated that current methods for insuring safety and reliability of high temperature equipment is inadequate. Because of these concerns, an understanding of the high-temperature crack growth process is very important and has led to the following studies of the high temperature failure process. This effort summarizes the results of some recent studies which investigate the phenomenon of high temperature creep fatigue crack growth. Experimental results which detail the process of creep fatigue, analytical studies which investigate why current methods are ineffective, and finally, a new approach which is based on the T{sup *}-integral and its ability to characterize the creep-fatigue crack growth process are discussed. The potential validity of this new predictive methodology is illustrated.
Grosse, Pablo; Yagupsky, Daniel; Winocur, Diego
2014-05-01
In order to evaluate the effects of growth and deformation (both separately and jointly) on volcano shape evolution, we performed a set of analogue experiments simulating these processes. The models consist of an initial symmetrical cone of 3 to 6 cm height composed of a mixture of quartz sand and plaster (cohesion of 100 to 300 Pa). Deformation was simulated through the relative motion of two underlying plates, generating a dextral E-W transcurrent fault. Growth was simulated through sedimentation of loads of granular material. For experiments simulating a fixed emission point, sedimentation was done on the same central point, whereas for experiments simulating variable emission points, sedimentation was done at the location of extrusion of corn syrup (pure and water-diluted, viscosities of 2 to 20 Pa.s) injected at the cone base, modeling magma intrusion. The experiments were documented by photographs and topographic scans, from which digital elevation models were constructed and used to calculate morphometric parameters. Five types of experiments were performed: -1. Deformation without growth (the initial cone is deformed by the E-W fault): the edifice elongates ENE-WSW, sub-perpendicular to σ1; a large graben forms at the summit region; the height/width ratio (H/W) strongly decreases. -2. Fixed-location growth without deformation (sedimentation on top of the initial cone): the edifice maintains its symmetrical, circular and regular shape, only size increases. -3. Variable-location growth without deformation (cycles of injection and sedimentation at the extrusion location): location of extrusions are variable, both within and between experiments; edifices are strongly irregular; elongation values and directions vary; H/W is maintained or decreases slightly. -4. Fixed-location growth with deformation (the initial cone is deformed by the fault and sedimentation is done on a central point): as with type (1) models, the cone elongates ENE-WSW and the central graben
Institute of Scientific and Technical Information of China (English)
ZHAO Guiping; LIU Shuwen; LIU Xiaohan
2004-01-01
Although porphyroblast microstmctures play an important role in structural and metamorphic studies, there are still controversies in the interpretation. The focus is how porphyroblasts grow during deformation and metamorphism.In this paper, we introduce a new approach, the Synchrotron Radiation X-Ray Fluorescence, to a hemi-quantitative interpretation of the growth mode of porphyroblasts. The analysis was done at the Beijing Synchrotron Radiation Facility.The specimens were sampled from metapelite of the Baoyintu Group, northern Urad Middle Banner, Inner Mongolia. The new method is successful for determining the microscopic distribution of trace elements in porphybroblasts. The results support the theory of deformation partition, which has been brought forth by Bell and his colleagues, and demonstrate the existence of porphyroblast growth phases and the growth mode of porphyroblasts by hemi-quantitative mineral chemical analysis. The porphyroblast grows stage by stage in the manner of the distribution of a roseleaf and is controlled by deformation. We call the growth stage of porphyroblast a growth phase.
Watching the growth of bulk grains during recrystallization of deformed metals
DEFF Research Database (Denmark)
Schmidt, Søren; Fæster Nielsen, Søren; Gundlach, C.;
2004-01-01
We observed the in situ growth of a grain during recrystallization in the bulk of a deformed sample. We used the three-dimensional x-ray diffraction microscope located at the European Synchrotron Radiation Facility in Grenoble, France. The results showed a very heterogeneous growth pattern......, contradicting the classical assumption of smooth and spherical growth of new grains during recrystallization. This type of in situ bulk measurement opens up the possibility of obtaining experimental data on scientific topics that before could only be analyzed theoretically on the basis of the statistical...
Influence of material's cyclic deformation behaviour on fatigue crack growth threshold
Institute of Scientific and Technical Information of China (English)
ZHANG Rui; SUN Yi; WANG zhen-qing
2008-01-01
To investigate the relation between material's cyclic plastic behaviour and fatigue crack growth, a new model is proposed. The model incorporated the two intrinsic properties of material' s cyclic plastic and crack tip' s deformation dislocation to interpret fatigue crack threshold. The relation between material's cyclic hardening parameters (cyclic hardening amplitude and cyclic hardening rate) and fatigue threshold is studied. Fatigue threshold is determined based on the dislocation-free zone (DFZ) model, the theory of cohesive zone and the cyclic deformation behaviour. The results show that fatigue threshold increases with the decrease of the amplitude of cyclic hardening and is independent of cyclic hardening rate, but fatigue crack growth rate increa-ses with the increase of cyclic hardening rate.
Effect of electric current pulse on grain growth in superplastic deformation of 2091 Al-Li alloy
Institute of Scientific and Technical Information of China (English)
刘志义; 许晓嫦; 崔建忠
2003-01-01
The effect of electric current pulse on the grain growth in the superplastic deformation of 2091 Al-Li alloy was investigated. Optical metallographic microstructure observation and average linear intercept measuring results show that at same strain, the grain size in the superplastic deformation loaded with electric current pulse is smaller than that unemploying electric current pulse, and so does the grain growth rate. TEM observation shows that the dislocation density at grain boundary in the superplastic deformation applied with electric current pulse is lower than that unemploying electric current pulse.It indicates that electric current pulse increases the rate of dislocation slip and climb in grain boundary, which leads to a decrease of both the density of the dislocation slipping across grain boundary at same strain rate and the driving force for grain growth, therefore the rate of grain growth decreases.The established model for grain growth shows an exponential relation of grain size with strain.
Laser Scanning Based Growth Analysis of Plants as a New Challenge for Deformation Monitoring
Dupuis, Jan; Holst, Christoph; Kuhlmann, Heiner
2016-03-01
Nowadays, the areal deformation analysis has become an important task in engineering geodesy. Thereby, not only manmade objects are of high interest, also natural objects, like plant organs, are focused more frequently. Thus, the analysis of leaf growth, i. e. the spatial development of the leaf surface, can be seen as a problem of deformation monitoring. In contrast to classical geodetic tasks, the absolute size of the deformation of the leaf surface is small, but usually great compared to the object size. Due to the optical characteristics of leaf surfaces, the point clouds, commonly acquired with high precision close-up laser scanners, provide a point-to-point distance that is small or equal compared to the measurement accuracy. Thus, the point clouds are usually processed and the leaf area is derived from a triangulation-based surface representation (mesh), resulting in a significant uncertainty of area calculation. In this paper, we illustrate the lacks of the mesh-based leaf area calculation. Using high precision gauge blocks as well as a number of tomato leaves, uncertainties of the area derivation are revealed and evaluated. The application of a B-spline approximation illustrates the advantages of an approximation-based approach and introduces the prospect for further research.
Ji, Wei; Rehman, Sahibzada Shakir; Wang, Weimin; Wang, Hao; Wang, Yucheng; Zhang, Jinyong; Zhang, Fan; Fu, Zhengyi
2015-10-01
A new ceramic sintering approach employing plastic deformation as the dominant mechanism is proposed, at low temperature close to the onset point of grain growth and under high pressure. Based on this route, fully dense boron carbide without grain growth can be prepared at 1,675-1,700 °C and under pressure of (≥) 80 MPa in 5 minutes. The dense boron carbide shows excellent mechanical properties, including Vickers hardness of 37.8 GPa, flexural strength of 445.3 MPa and fracture toughness of 4.7 MPa•m0.5. Such a process should also facilitate the cost-effective preparation of other advanced ceramics for practical applications.
Modeling the Impact of Fracture Growth on Fluid Displacements in Deformable Porous Media
Santillán, D.; Cueto-Felgueroso, L.; Juanes, R.
2015-12-01
Coupled flow and geomechanics is a critical research challenge in engineering and the geosciences. The flow of a fluid through a deformable porous media is present in manyenvironmental, industrial, and biological processes,such as the removal of pollutants from underground water bodies, enhanced geothermal systems, unconventional hydrocarbon resources or enhanced oil recovery techniques. However, the injection of a fluid can generate or propagate fractures, which are preferential flow paths. Using numerical simulation, we study the interplay between injection and rock mechanics, and elucidate fracture propagation as a function of injection rate, initial crack topology and mechanical rock properties. Finally, we discuss the role of fracture growth on fluid displacements in porous media. Figure: An example of fracture (in red) propagated in a porous media (in blue)
Cobanoglu, Mutlu; Cullu, Emre; Kilimci, Figen Sevil; Ocal, Mehmet Kamil; Yaygingul, Rahime
2016-06-01
Background and purpose - Coronal and sagittal plane long bone deformities can be corrected with guided growth, whereas transverse plane rotational deformities require osteotomy and internal or external fixation. We investigated whether rotational changes can be introduced with the plating technique. Methods - 45 rabbits (6 weeks old) were divided into 3 groups. The unoperated right tibia was used as control. In groups 1 and 3, two plates were placed obliquely to the long axis and in different directions. In group 2, a sham operation was performed with screws. Animals in groups 1 and 2 were followed for 4 weeks. In group 3 the implants were removed 4 weeks after the operation to observe rebound effect, and the animals were followed for another 4 weeks. The tibial torsion was assessed on computed tomography (CT). External rotation was accepted as a negative value. Results - In group 1, mean torsion was -20° (SD 7.9) in the right tibia and -2.9° (SD 7.2) in the left tibia (p < 0.001). In group 2, mean torsion was -23° (SD 4.9) in the right tibia and -26° (SD 6.5) in the left tibia (p = 0.2). In group 3, mean torsion was -21° (SD 6.3) in the right tibia and -9.5° (SD 5.3) in the left tibia (p < 0.001). Intergroup evaluation for left torsion showed a significant difference between group 2 and the other groups (p < 0.001). When the rebound effect was evaluated, there was no statistically significant difference between groups 1 and 3 (p = 0.08). Interpretation - A rotational change was attained with this technique. Although a rebound effect was seen after implant removal, it did not reach statistical significance. The final rotational change remained constant. PMID:26900795
Cobanoglu, Mutlu; Cullu, Emre; Kilimci, Figen Sevil; Ocal, Mehmet Kamil; Yaygingul, Rahime
2016-01-01
Background and purpose Coronal and sagittal plane long bone deformities can be corrected with guided growth, whereas transverse plane rotational deformities require osteotomy and internal or external fixation. We investigated whether rotational changes can be introduced with the plating technique. Methods 45 rabbits (6 weeks old) were divided into 3 groups. The unoperated right tibia was used as control. In groups 1 and 3, two plates were placed obliquely to the long axis and in different directions. In group 2, a sham operation was performed with screws. Animals in groups 1 and 2 were followed for 4 weeks. In group 3 the implants were removed 4 weeks after the operation to observe rebound effect, and the animals were followed for another 4 weeks. The tibial torsion was assessed on computed tomography (CT). External rotation was accepted as a negative value. Results In group 1, mean torsion was −20° (SD 7.9) in the right tibia and −2.9° (SD 7.2) in the left tibia (p < 0.001). In group 2, mean torsion was −23° (SD 4.9) in the right tibia and −26° (SD 6.5) in the left tibia (p = 0.2). In group 3, mean torsion was −21° (SD 6.3) in the right tibia and −9.5° (SD 5.3) in the left tibia (p < 0.001). Intergroup evaluation for left torsion showed a significant difference between group 2 and the other groups (p < 0.001). When the rebound effect was evaluated, there was no statistically significant difference between groups 1 and 3 (p = 0.08). Interpretation A rotational change was attained with this technique. Although a rebound effect was seen after implant removal, it did not reach statistical significance. The final rotational change remained constant. PMID:26900795
Institute of Scientific and Technical Information of China (English)
CHANG Li-min; LIU Jian-hua
2006-01-01
The formation and growth of thermal fatigue crack in chromium wear resistant cast iron was investigated, and the effect of hot deformation on the crack was analyzed by means of optical microscope and scanning electron microscope and high frequency induction thermal fatigue tester. The results show that eutectic carbide is the main location and passage for initiation and extension of thermal fatigue cracks, hot deformation can improve the eutectic carbide′s morphology and distribution, inhibit the generation and propagation of thermal fatigue cracks. In the experiment, the propagation rate of thermal fatigue crack reduces with the quantity of hot deformation increasing, which was analyzed in the point view of the activation energy of crack propagation.
Growth and deformation structure of gradient and layer-gradient Ti-Al-Si-Cu-N coatings
Energy Technology Data Exchange (ETDEWEB)
Ovchinnikov, Stanislav V., E-mail: ovm@spti.tsu.ru; Pinzhin, Yurii P., E-mail: pinzhin@phys.tsu.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Korotaev, Alexandr D., E-mail: korotaev@phys.tsu.ru [National Research Tomsk State University, Tomsk, 634050 (Russian Federation)
2014-11-14
The features of the growth structure and modification of gradient and layer-gradient Ti-Al-Si-Cu-N coatings in the areas of deformation and fracture during indentation and scratch testing were investigated using transmission and scanning electron microscopy methods. The influence of the concentration of alloying elements and displacement potential in the substrate on the secondary sputtering, phase composition and the level of combined torsion and bending of the crystal lattice of doped TiN were determined. It was found out that the size of the crystals in deformation location bands grows with deformation of gradient nanocrystal coatings. The article shows that layer-gradient coatings combining submicrocrystalline and nanocrystalline structures have the increased plasticity and fracture toughness due to enhanced density of interfaces and formation of the soft metal phase (Cu) in the surface layer.
Growth and deformation structure of gradient and layer-gradient Ti-Al-Si-Cu-N coatings
International Nuclear Information System (INIS)
The features of the growth structure and modification of gradient and layer-gradient Ti-Al-Si-Cu-N coatings in the areas of deformation and fracture during indentation and scratch testing were investigated using transmission and scanning electron microscopy methods. The influence of the concentration of alloying elements and displacement potential in the substrate on the secondary sputtering, phase composition and the level of combined torsion and bending of the crystal lattice of doped TiN were determined. It was found out that the size of the crystals in deformation location bands grows with deformation of gradient nanocrystal coatings. The article shows that layer-gradient coatings combining submicrocrystalline and nanocrystalline structures have the increased plasticity and fracture toughness due to enhanced density of interfaces and formation of the soft metal phase (Cu) in the surface layer
Zhang, Zhiliang; Sun, Jimin; Tian, Zhonghua; Gong, Zhijun
2016-03-01
The collision between India and Eurasia in the Cenozoic has caused a series of intracontinental deformation in the foreland basins of Tian Shan, but there are debates about the timing of tectonic deformation and the relationship between tectonic uplift and sediment accumulation in the foreland basins. Based on the magnetostratigraphy of growth strata in the Baicheng Depression, Southern Tian Shan, we suggest that an episode of crustal shortening in the late Cenozoic evidenced by syntectonic growth strata in the Kelasu-Yiqikelike structural belt (KYSB) initiated at ∼5.3 Ma, since then the sedimentation rate accelerated abruptly and coarse molasse deposits accumulated. Combined with the results of growth strata on both flanks of Tian Shan and the fact that the Xiyu Formation on the southern limb of the Kasangtuokai Anticline was involved into the growth strata, we conclude that the period from ∼7-5 Ma to the early Pleistocene was one of the important episodes of intracontinental deformation in the foreland basins of Tian Shan, as a response to the Cenozoic collision between India and Eurasia.
Michon, L.; Cayol, V.; Letourneur, L.; PELTIER, A.; Villeneuve, Nicolas; Staudacher, T.
2009-01-01
The overall morphology of basaltic volcanoes mainly depends on their eruptive activity (effusive vs. explosive), the geometry of the rift zones and the characteristics of both endogenous and exogenous growth processes. The origin of the steep geometry of the central cone of Piton de la Fournaise volcano, which is unusual for a basaltic effusive volcano, and its deformation are examined with a combination of a detailed morphological analysis, field observations, GPS data from the Piton de la F...
Kinetics of Austenite Grain Growth During Heating and Its Influence on Hot Deformation of LZ50 Steel
Du, Shiwen; Li, Yongtang; Zheng, Yi
2016-07-01
Grain growth behaviors of LZ50 have been systematically investigated for various temperatures and holding times. Quantitative evaluations of the grain growth kinetics over a wide range of temperature (950-1200 °C) and holding time (10-180 min) have been performed. With the holding time kept constant, the average austenite grain size has an exponential relationship with the heating temperature, while with the heating temperature kept constant, the relationship between the austenite average grain size and holding time is a parabolic curve approximately. The holding time dependence of average austenite grain size obeys the Beck's equation. As the heating temperature increases, the time exponent for grain growth n increases from 0.21 to 0.39. On the basis of previous models and experimental results, taking the initial grain size into account, the mathematical model for austenite grain growth of LZ50 during isothermal heating and non-isothermal heating is proposed. The effects of initial austenite grain size on hot deformation behavior of LZ50 are analyzed through true stress-strain curves under different deformation conditions. Initial grain size has a slight effect on peak stress.
Yang, Yi; Zoback, Mark
2016-02-01
We report laboratory studies of the time-dependent deformation of core samples from four different formations in the Williston Basin—the Lodgepole Formation, the Middle and Lower Bakken Formations, and Three Forks Formation. The laboratory tests reveal varying amounts of viscoplastic deformation in response to applied differential stress. The time-dependent deformation is generally greater in rocks with higher clay and organic content and can be described by a power-law function. Because the magnitude of the creep strain is linearly proportional to the applied differential stress, we can utilize viscoelastic theory and geophysical logs to estimate the degree to which tectonic stress is affected by viscoplastic stress relaxation. We suggest that viscoplastic stress relaxation results in the Upper and Lower Bakken Formations acting as frac barriers during hydraulic fracture stimulation in the Middle Bakken, but the Lodgepole and the Three Forks Formations are not frac barriers.
International Nuclear Information System (INIS)
Tada, Paris and Gamble have used the tearing modulus approach to examine the stability of growth of a through-wall circumferential crack in a 304 stainless steel circular cylindrical pipe subject to bending deformation. They showed that crack growth is stable, in the sense that growth requires the rotation imposed at the pipe-ends to be increased, provided the pipe length is less than a critical length Lsub(c), which is given by their analysis. The Tada-Paris-Gamble analysis focuses on the question of the stability, or otherwise, of crack growth at the onset of crack extension. The analysis does not consider the possibilities that (a) instability might occur after some stable crack growth, and (b) arrest might occur after some unstable growth. A study of these aspects of the circumferential crack growth problem using the tearing modulus approach is precluded by the geometry dependence of the J-crack growth resistance curve. Consequently the present paper uses a crack tip opening angle criterion to describe crack growth, and thereby demonstrates that possibilities (a) and (b) should both occur, depending on the initial crack length and pipe length. In terms of relevance to the technologically important problem of cracking in Boiling Water Reactor piping, the important conclusion stemming from the paper's analysis is that stability of crack growth after the onset of crack extension is assured if the pipe length is less than a critical length L'sub(c). L'sub(c) is less than Lsub(c), the critical length relevant to the onset of crack extension, but it is still appreciably greater than the pipe run lengths in actual reactor piping systems, and safety against guillotine failure of a pipe is therefore generally assured. (author)
International Nuclear Information System (INIS)
We have simultaneously measured the evolution of intermetallic volume, stress, and whisker density in Sn and Pb-Sn alloy layers on Cu to study the fundamental mechanisms controlling whisker formation. For pure Sn, the stress becomes increasingly compressive and then saturates, corresponding to a plastically deformed region spreading away from the growing intermetallic particles. Whisker nucleation begins after the stress saturates. Pb-Sn layers have similar intermetallic growth kinetics but the resulting stress and whisker density are much less. Measurements after sputtering demonstrate the important role of the surface oxide in inhibiting stress relaxation
Bunkholt, Sindre
2013-01-01
Phenomena related to annealing of aluminium alloys are among the least understood in aluminium metallurgy but very important for industrial thermo-mechanical processing i.e. deformation and annealing. Physical models are used to predict recovery and recrystallization behaviour, and associated material properties, industrially. However, alloy development, e.g. to incorporate more recycled aluminium, has shown that current softening models are not satisfactory. Thus, improvements do require a b...
Naghizadeh, Meysam; Mirzadeh, Hamed
2016-08-01
Microstructural evolutions during annealing of a plastically deformed AISI 304 stainless steel were investigated. Three distinct stages were identified for the reversion of strain-induced martensite to austenite, which were followed by the recrystallization of the retained austenite phase and overall grain growth. It was shown that the primary recrystallization of the retained austenite postpones the formation of an equiaxed microstructure, which coincides with the coarsening of the very fine reversed grains. The latter can effectively impair the usefulness of this thermomechanical treatment for grain refinement at both high and low annealing temperatures. The final grain growth stage, however, was found to be significant at high annealing temperatures, which makes it difficult to control the reversion annealing process for enhancement of mechanical properties. Conclusively, this work unravels the important microstructural evolution stages during reversion annealing and can shed light on the requirements and limitations of this efficient grain refining approach.
Naghizadeh, Meysam; Mirzadeh, Hamed
2016-06-01
Microstructural evolutions during annealing of a plastically deformed AISI 304 stainless steel were investigated. Three distinct stages were identified for the reversion of strain-induced martensite to austenite, which were followed by the recrystallization of the retained austenite phase and overall grain growth. It was shown that the primary recrystallization of the retained austenite postpones the formation of an equiaxed microstructure, which coincides with the coarsening of the very fine reversed grains. The latter can effectively impair the usefulness of this thermomechanical treatment for grain refinement at both high and low annealing temperatures. The final grain growth stage, however, was found to be significant at high annealing temperatures, which makes it difficult to control the reversion annealing process for enhancement of mechanical properties. Conclusively, this work unravels the important microstructural evolution stages during reversion annealing and can shed light on the requirements and limitations of this efficient grain refining approach.
Indian Academy of Sciences (India)
Weichang Xu; Pinqiang Dai; Xiaolei Wu
2010-10-01
In the present study defect-free nanocrystalline (nc) Ni–Co alloys with the Co content ranging from 2.4–59.3% (wt.%) were prepared by pulse electrodeposition. X-ray diffraction analysis shows that only a single face-centred cubic solid solution is formed for each alloy and that the grain size reduces monotonically with increasing Co content, which is consistent with transmission electron microscopy (TEM) observations. In the nc Ni–Co alloys, both the ultimate tensile strength and the elongation to failure increase as the Co content increases. The TEM observations reveal that stress-induced grain growth during tensile deformation is significantly suppressed for the nc Ni–Co alloys rich in Co in sharp contrast to those poor in Co. We believe that sufficient solutes could effectively pin grain boundaries making grain boundary motions (e.g. grain boundary migration and/or grain rotation) during deformation more difficult. Thus, stress-induced grain growth is greatly suppressed. At the same time, shear banding plasticity instability is correspondingly delayed leading to the enhanced ductility.
International Nuclear Information System (INIS)
The dissolution and growth of Al3(Er, Zr) precipitates during tensile fatigue experiments were investigated by quasi-in situ and post-mortem scanning transmission electron microscopy with Z contrast imaging and X-ray energy dispersive spectroscopy. Al3(Er, Zr) particles were observed with both non-core–shell and core–shell structures, which were formed during multiple-stage precipitations, in an Al–Mg–Er alloy. After fatigue deformations, the average size of the non-core–shell structured precipitates increased significantly. By tracing the same precipitate particles before and after a high-cycle fatigue test, quasi-in situ electron microscopy revealed that the increase of average particle size is associated with the substantial dissolution of small non-core–shell structured Al3(Er, Zr) particles, whose diameters are generally less than 15 nm, and a consequent growth of larger non-core–shell Al3(Er, Zr) precipitates. On the contrary, the core–shell structured Al3(Er, Zr) precipitates remain stable during high-cycle fatigue tests. Possible mechanisms for the dissolution and growth of non-core–shell structured Al3(Er, Zr) precipitates are discussed in terms of particle size, interfacial energy and lattice mismatch, in comparison to the stable core–shell structured precipitates
Dauteuil, Olivier; Bessin, Paul; Guillocheau, François
2015-03-01
We reconstruct the history of topographic growth in southern Africa on both sides of the Orange River valley from an integrated analysis of erosion surfaces, crustal deformation and climate change. First, we propose an inventory of erosion surfaces observed in the study area and classify them according to their most likely formative process, i.e. chemical weathering or mechanical erosion. Among the various land units observed we define a new class of landform: the pedivalley, which corresponds to a wide valley with a flat erosional floor. In the Orange River valley, we mapped three low-relief erosion surfaces, each bevelling a variety of lithologies. The oldest and most elevated is (1) a stripped etchplain evolving laterally into (2) a stepped pediplain bearing residual inselbergs; (3) a younger pediplain later formed in response to a more recent event of crustal deformation. These are all Cenozoic landforms: the etchplain is associated with a late Palaeocene to middle Eocene weathering event, and the two pediplains are older than the middle Miocene alluvial terraces of the Orange River. Landscape evolution was first driven by slow uplift (10 m/Ma), followed by a second interval of uplift involving a cumulative magnitude of at least 200 m. This event shaped the transition between the two pediplains and modified the drainage pattern. A final phase of uplift (magnitude: 60 m) occurred after the Middle Miocene and drove the incision of the lower terraces of the Orange River. Climate exerted a major control over the denudation process, and involved very humid conditions responsible for lateritic weathering, followed by more arid conditions, which promoted the formation of pedivalleys. Collectively, these produce pediplains.
Castro, Antonio; Fernández, Carlos
1998-09-01
The Plasenzuela pluton in the Central Extremadura batholith in the southern Iberian Massif, is an example of permissive emplacement in relation to the tectonic development of extensional fractures in the upper continental crust. Paradoxically, this pluton has a concordant structural pattern which is classically attributed to diapirism or ballooning. This pattern consists of the following elements: (a) nearly elliptical shape in the horizontal section; (b) conformity of the pre-existing aureole structures to the shape of the pluton contacts; and (c) development of a crenulation cleavage, parallel to the contacts, in the vicinity of the pluton walls. All these features have been interpreted in many plutons as resulting from the pushing-aside of the country rock structures due to the expansion of the pluton. However, the detailed structural relationships in the aureole do not favour a forceful emplacement mechanism. By contrast, these relationships constitute prime evidence of permissive intrusion in extensional fractures. According to this interpretation, the concordant shape of the pluton was acquired by syn-plutonic opening of a mixed tensional-shear fracture, parallel to the main foliation in the host rocks, and by folding of the fracture walls together with the previous anisotropy of the country rocks. This is a growth-deformation process that can operate at local conditions in the upper continental crust giving rise to concordant syn-tectonic plutons.
Guillocheau, François; Dauteuil, Olivier; Baby, Guillaume; Robin, Cécile
2013-04-01
The South African Plateau is one of the largest very long wavelength relief (x1000 km) of the world that could be related to mantle dynamics and the effect of the African superplume. Unfortunately, the timing of the uplift and the different steps of the relief growth are still debated with a Late Cretaceous uplift scenario and an Oligocene one. Whatever model, few attentions were paid to the evolution of the overall geomorphic system, from the upstream erosional system to the downstream depositional system. This study is based, onshore, on the mapping and chronology of all the macroforms (weathering surfaces and associated alterites, pediments and pediplains, incised rivers, wave-cut platforms) dated by intersection with the few preserved sediments and the volcanics (mainly kimberlites pipes) and, offshore, on a more classical dataset of seismic lines and petroleum wells (characterization and dating of forced regression, sediment volume measurement, etc..). The main result of this study is that the South African Plateau is an old Late Cretaceous Plateau reactivated during Paleogene times and fossilized since the Middle Miocene. • During Late Cretaceous, in a semiarid climatic setting, the main uplift occurred from the east (around 95 Ma) to the west (around 75 Ma) and could result from the migration of the African plate over the African superplume: This is the paroxysm of the erosion with the growth of a large delta offshore present-day Orange River mouth (sedimentation rate around 100 000 km3/Ma). • During Paleocene - Mid Eocene times, in more humid conditions and in response to a more subtle long wavelength deformation, pedimentation occurred mainly localised along Cape Fold Belt feeding a large delta offshore western Cape Peninsula. During Mid Eocene times, all those landscapes are fossilized and weathered by laterites. • Late Eocene and Oligocene is the second period of uplift of the Plateau, localised along its Indian Ocean side (Drackensberg Moutains
Indian Academy of Sciences (India)
A Chattopadhyay; N Ghosh
2007-10-01
Polyphase deformation and metamorphism of pelitic schists of Chorbaoli Formation of Sausar Group in and around Ramtek area,Nagpur district,Maharashtra,India has led to the development of garnet and staurolite porphyroblasts in a predominantly quartz –mica matrix.Microstructural study of oriented thin sections of these rocks shows that garnet and staurolite have different growth histories and these porphyroblasts share a complex relationship with the matrix.Garnet shows at least two phases of growth –ﬁrst intertectonic between D1 and D2 (pre-D2 phase)and then syn-tectonic to post-tectonic with respect to D2 deformation.Growth of later phase of garnet on the earlier (pre-D2 garnet grains has led to the discordance of quartz inclusion trails between core and rim portion of the same garnet grain.Staurolite develops only syn-D2 and shows close association with garnet of the later phase.The peak metamorphic temperature thus coincided with D2 deformation,which developed the dominant crenulation schistosity (S2 ,regionally persistent in the terrain.The metamorphic grade reached up to middle amphibolite facies in the study area, which is higher than the adjoining southern parts of Sausar Fold Belt.
Growth mechanism of Al2Cu precipitates during in situ TEM heating of a HPT deformed Al–3wt.%Cu alloy
International Nuclear Information System (INIS)
The microstructural evolution of Al2Cu precipitates in an ultrafine-grained Al–3wt.% Cu model alloy produced by high-pressure torsion (HPT) was studied by in situ transmission electron microscopy (TEM). The precipitation growth was systematically investigated by isothermal heating experiments in the temperature range of 120 °C to 170 °C. The experimental data is analysed with respect of the diffusion kinetics and activation energy to determine the most prominent diffusion path: lattice or grain boundary diffusion. The results imply that grain boundary diffusion is the relevant mechanism for Al2Cu growth in the HPT deformed material
Böhm, Harald; Stief, Felix; Sander, Klaus; Hösl, Matthias; Döderlein, Leonhard
2015-09-01
Malaligned knees are predisposed to the development and progression of unicompartmental degenerations because of the excessive load placed on one side of the knee. Therefore, guided growth in skeletally immature patients is recommended. Indication for correction of varus/valgus deformities are based on static weight bearing radiographs. However, the dynamic knee abduction moment during walking showed only a weak correlation to malalignment determined by static radiographs. Therefore, the aim of the study was to measure the effects of guided growth on the normalization of frontal plane knee joint moments during walking. 15 legs of 8 patients (11-15 years) with idiopathic axial varus or valgus malalignment were analyzed. 16 typically developed peers served as controls. Instrumented gait analysis and clinical assessment were performed the day before implantation and explantation of eight-plates. Correlation between static mechanical tibiofemoral axis angle (MAA) and dynamic frontal plane knee joint moments and their change by guided growth were performed. The changes in dynamic knee moment in the frontal plane following guided growth showed high and significant correlation to the changes in static MAA (R=0.97, p<0.001). Contrary to the correlation of the changes, there was no correlation between static and dynamic measures in both sessions. In consequence two patients that had a natural knee moment before treatment showed a more pathological one after treatment. In conclusion, the changes in the dynamic load situation during walking can be predicted from the changes in static alignment. If pre-surgical gait analysis reveals a natural load situation, despite a static varus or valgus deformity, the intervention must be critically discussed. PMID:26159802
International Nuclear Information System (INIS)
A Ti-15Mo-5Zr-3Al alloy with a bcc structure are promising materials for biomedical application and were examined. The focus of this study was on the effect of heat treatment on microstructure and plastic deformation behaviour using a single crystal. The single crystal was successfully obtained by a floating zone method at a crystal growth rate of 2.5 mm/h. A slip at the dislocation was present irrespective of heat treatment at 573K or 673K for 1.2 ks or 300 ks. The yield stress at the [149] loading axis varied significantly depending on microstructure, especially from the precipitation of the a phase. Al addition suppresses generation of the σ phase and increases the yield stress at the same time.
Telesman, Jack; Ghosn, Louis J.
1988-01-01
An investigation of the fatigue crack growth (FCG) behavior of PWA 1480 single crystal nickel base superalloy was conducted. Typical Paris region behavior was observed above a delta K of 8 MPa sq rt of m. However, below that stress intensity range, the alloy exhibited highly unusual behavior. This behavior consisted of a region where the crack growth rate became essentially independent of the applied stress intensity. The transition in the FCG behavior was related to a change in the observed crack growth mechanisms. In the Paris region, fatigue failure occurred along (111) facets; however, at the lower stress intensities, (001) fatigue failure was observed. A mechanism was proposed, based on barriers to dislocation motion, to explain the changes in the observed FCG behavior. The FCG data were also evaluated in terms of a recently proposed stress intensity parameter, K sub rss. This parameter, based on the resolved shear stresses on the slip planes, quantified the crack driving force as well as the mode I delta K, and at the same time was also able to predict the microscopic crack path under different stress states.
Bagnardi, Marco; Amelung, Falk; Poland, Michael P.
2013-01-01
Space-geodetic measurements of surface deformation produced by the most recent eruptions at Fernandina – the most frequently erupting volcano in the Galápagos Archipelago – reveal that all have initiated with the intrusion of subhorizontal sills from a shallow magma reservoir. This includes eruptions from fissures that are oriented both radially and circumferentially with respect to the summit caldera. A Synthetic Aperture Radar (SAR) image acquired 1–2 h before the start of a radial fissure eruption in 2009 captures one of these sills in the midst of its propagation toward the surface. Galápagos eruptive fissures of all orientations have previously been presumed to be fed by vertical dikes, and this assumption has guided models of the origin of the eruptive fissure geometry and overall development of the volcanoes. Our findings allow us to reinterpret the internal structure and evolution of Galápagos volcanoes and of similar basaltic shields. Furthermore, we note that stress changes generated by the emplacement of subhorizontal sills feeding one type of eruption may control the geometry of subsequent eruptive fissures. Specifically, circumferential fissures tend to open within areas uplifted by sill intrusions that initiated previous radial fissure eruptions. This mechanism provides a possible explanation for the pattern of eruptive fissures that characterizes all the western Galápagos volcanoes, as well as the alternation between radial and circumferential fissure eruptions at Fernandina. The same model suggests that the next eruption of Fernandina will be from a circumferential fissure in the area uplifted by the 2009 sill intrusion, just southwest of the caldera rim.
Indian Academy of Sciences (India)
A A Shah; T H Bell
2012-12-01
In situ dating of monazite grains preserved as inclusions within foliations defining FIAs (foliation inflection/intersection axes preserved within porphyroblasts) contained within garnet, staurolite, andalusite and cordierite porphyroblasts provides a chronology of ages that matches the FIA succession for the Big Thompson region of the northern Colorado Rocky Mountains. FIA sets 1, 2 and 3 trending NE–SW, E–W and SE–NW were formed at 1760.5 ± 9.7, 1719.7 ± 6.4 and 1674 ± 11± Ma, respectively. For three samples where garnet first grew during just one of each of these FIAs, the intersection of Ca, Mg, and Fe isopleths in their cores indicate that these rocks never got above 4 kbars throughout the Colorado Orogeny. Furthermore, they remained around approximately the same depth for ∼250 million years to the onset of the younger Berthoud Orogeny at 1415 ± 16 Ma when the pressure decreased slightly as porphyroblasts formed with inclusion trails preserving FIA set 4 trending NNE–SSW. No porphyroblast growth occurred during the intervening ∼250 million years of quiescence, even though the PT did not change over this period. This confirms microstructural evidence gathered over the past 25 years that crenulation deformation at the scale of a porphyroblast is required for reactions to re-initiate and enable further growth.
International Nuclear Information System (INIS)
The following comprises a literary review of the effects of prenatal X-ray irradiation, known mainly from the mouse. Our own investigations were carried out with NMRI mice which on gestation days 11-13, 11-16 or 14-16 were exposed to whole-body irradiation comprising individual daily doses of between 80 and 160 R. All the examinations were carried out on the 18th day of gestation. Findings of special nature were ascertained on the talus and calcaneus. These bones indicate that the X-ray irradiation has an accelerating effect on development. It was possible to ascertain a corresponding effect with regard to the deformations of the os supraoccipital. After irradiation with 3 x 120 R and 3 x 160 R on the 11th-13th gestation days, both inhibitory deformities and also the occurence of an additional, novel bone anlage were observed. These findings were subjected to detailed histological examinations. In doing so, it was found that following a single irradiation with 200 R on the 12th day of gestation, 86,6% of the fetuses showed hyperostoses on the roof of the skull. In 13,2% of all cases there was in addition a clear, abnormal chondrification of the neurocranium, at the same time combined with an excessive formation of the bone, which protruded deep into the cerebral hemispheres. The patogeneses of this excessive growth phenomenon is explained on the basis of the complex relationship between the fetal brain formation and the formation of the skull cap. (orig./AJ)
International Nuclear Information System (INIS)
paper, first, the validity and the usefulness of the lattice-gas model and the lattice Boltzmann method for the numerical analysis of two-phase flow are examined by applying the two-phase fluid model of these methods to the phenomena of the falling droplet and the rising bubble. Next, on the basis of the examination of its numerical results, the horizontal stratified two-phase flow, which is the fundamental and important flow and often observed in a practical situation, is simulated by use of the HCZ model that is the two-phase fluid model of the lattice Boltzmann method proposed by He, Chen, and Zhang. The HCZ model can simulate Rayleigh-Taylor instability which shows complex interfacial phenomena. It is verified that the simulated interfacial growth is subject to the Kelvin-Helmholtz instability theory and can reproduce the curve concerning the interfacial growth of the theoretical flow regime map proposed by Taitel and Dukler (T-D map). Furthermore, it is found that the interfacial growth in the channel with the narrow width needs more superficial flow velocity than that given by the T-D map. In the simulation of the droplet generation in the horizontal stratified two-phase flow, it is verified that the HCZ model can also reproduce the experimental correlation proposed by Ishii and Grolmes within the range of the distribution of experimental data. According to the results of this report, it is found that the HCZ model of the lattice Boltzmann method can simulate complex interfacial phenomena in the horizontal stratified two-phase flow and reproduce the theoretical flow regime map and the experimental correlation. Considering the application of this model to more practical two-phase flow, it is also seen that this model has some problems which have to be solved, such as practical density difference, thermal influence and so on. (author)
Energy Technology Data Exchange (ETDEWEB)
Kelemen, Peter
2012-08-24
Topics covered include: Failure At High Confining Pressure; Fluid-assisted Slip, Earthquakes & Fracture; Reaction-driven Cracking; Fluid Transport, Deformation And Reaction; Localized Fluid Transport And Deformation; Earthquake Mechanisms; Subduction Zone Dynamics And Crustal Growth.
DEFF Research Database (Denmark)
Hansen, N.; Huang, X.; Hughes, D.A.
2004-01-01
Microstructural characterization and modeling has shown that a variety of metals deformed by different thermomechanical processes follows a general path of grain subdivision, by dislocation boundaries and high angle boundaries. This subdivision has been observed to very small structural scales...
Delaney, Paul T.; Pollard, David D.
1981-01-01
We have studied a small group of minette dikes and plugs that crop out within a flat-lying sequence of siltstone and shale near Ship Rock, a prominent volcanic throat of tuff breccia in northwestern New Mexico. Seven dikes form a radial pattern about Ship Rock we describe in detail the northeastern dike, which has an outcrop length of about 2,900 m, an average thickness of 2.3 m, and a maximum thickness of 7.2 m. The dike is composed of 35 discrete segments arranged in echelon; orientation. of dike segments ranges systematically from N. 52? E. to N. 66? E. A prominent joint set strikes parallel to the segments and is localized within several tens of meters of the dike. Regional joint patterns display no obvious relation to dike orientation. Small offsets of segment contacts, as well as wedge-shaped bodies of crumpled host rock within segments mark the sites of coalescence of smaller segments during dike growth. Bulges in the dike contact, which represent a nondilational component of growth, indicate that wall rocks were brecciated and eroded during the flow of magma. Breccias make up about 9 percent of the 7,176-m 2 area of the dike, are concentrated in its southwest half, and are commonly associated with its thickest parts. We also describe three subcircular plugs; each plug is smaller than 30 m in diameter, is laterally associated with a dike, and contains abundant breccias. Field evidence indicates that these plugs grew from the dikes by brecciation and erosion of wallrocks and that the bulges in the contact of the northeastern dike represent an initial stage of this process. From continuum-mechanical models of host-rock deformation, we conclude that dike propagation was the dominant mechanism for creating conduits for magma ascent where the host rock was brittle and elastic. At a given driving pressure, dikes dilate to accept greater volumes of magma than plugs, and for a given dilation, less work is done on the host rocks. In addition, the pressure required
Bilateral cleft lip nasal deformity
Singh Arun; Nandini R.
2009-01-01
Bilateral cleft lip nose deformity is a multi-factorial and complex deformity which tends to aggravate with growth of the child, if not attended surgically. The goals of primary bilateral cleft lip nose surgery are, closure of the nasal floor and sill, lengthening of the columella, repositioning of the alar base, achieving nasal tip projection, repositioning of the lower lateral cartilages, and reorienting the nares from horizontal to oblique position. The multiplicity of procedures in the li...
Bilateral cleft lip nasal deformity
Directory of Open Access Journals (Sweden)
Singh Arun
2009-01-01
Full Text Available Bilateral cleft lip nose deformity is a multi-factorial and complex deformity which tends to aggravate with growth of the child, if not attended surgically. The goals of primary bilateral cleft lip nose surgery are, closure of the nasal floor and sill, lengthening of the columella, repositioning of the alar base, achieving nasal tip projection, repositioning of the lower lateral cartilages, and reorienting the nares from horizontal to oblique position. The multiplicity of procedures in the literature for correction of this deformity alludes to the fact that no single procedure is entirely effective. The timing for surgical intervention and its extent varies considerably. Early surgery on cartilage may adversely affect growth and development; at the same time, allowing the cartilage to grow in an abnormal position and contributing to aggravation of deformity. Some surgeons advocate correction of deformity at an early age. However, others like the cartilages to grow and mature before going in for surgery. With peer pressure also becoming an important consideration during the teens, the current trend is towards early intervention. There is no unanimity in the extent of nasal dissection to be done at the time of primary lip repair. While many perform limited nasal dissection for the fear of growth retardation, others opt for full cartilage correction at the time of primary surgery itself. The value of naso-alveolar moulding (NAM too is not universally accepted and has now more opponents than proponents. Also most centres in the developing world have neither the personnel nor the facilities for the same. The secondary cleft nasal deformity is variable and is affected by the extent of the original abnormality, any prior surgeries performed and alteration due to nasal growth. This article reviews the currently popular methods for correction of nasal deformity associated with bilateral cleft lip, it′s management both at the time of cleft lip repair
Deformation of vanadium and niobium on hydridation
International Nuclear Information System (INIS)
Deformation of wire samples made of polycrystalline vanadium and niobium on hydridation is studied. It is shown that sample allowance under loading after deformation below the yield strength doesn't cause considerable creep. Cathode saturation of samples with hydrogen sharply accelerates vanadium microdeformation velocity, that is connected with the beginning of intensive vanadium hydride precipitation (β-phase) from α-solid vanadium-hydrogen solution. Niobium hydridation at the first stage doesn't hydridation at the first stage doesn't cause negative deformation, then change in deformation direction takes place at the moment of intensive growth of the hydride phase. The conclusion is made that in both metals microdeformation is determined by contribution of two components: deformation caused by changing a shift module of metal-hydrogen system, and deformation caused by the oriented growth of the hydride phase in the field of apphed stresses
Cavity coalescence in superplastic deformation
Energy Technology Data Exchange (ETDEWEB)
Stowell, M.J.; Livesey, D.W.; Ridley, N.
1984-01-01
An analysis of the probability distribution function of particles randomly dispersed in a solid has been applied to cavitation during superplastic deformation and a method of predicting cavity coalescence developed. Cavity size distribution data were obtained from two microduplex nickel-silver alloys deformed superplastically to various extents at elevated temperature, and compared to theoretical predictions. Excellent agreement occurred for small void sizes but the model underestimated the number of voids in the largest size groups. It is argued that the discrepancy results from a combination of effects due to non-random cavity distributions and to enhanced growth rates and incomplete spheroidization of the largest cavities.
Institute of Scientific and Technical Information of China (English)
刘洪
2012-01-01
主要针对高频线圈于单晶生长过程中，在高频电流及棒体的高温作用下，产生的附加扭矩，改变线圈的设计外形，进行了原因研究、理论计算，并对单晶生长的影响进行了分析。通过采取适当的措施，降低由于线圈的形变对单晶的影响，提高单晶的成晶率。%Change the shape of the coil design for high-frequency coil in the crystal growth process, high-frequency current and the high temperature of the rods, resulting in additional torque, why study the theoretical calculations, and crystal growth the impact analysis. Take appropriate measures to reduce the coil deformation of single crystals, to improve the yield of single crystal.
Deformation of in-service pressure tubes
International Nuclear Information System (INIS)
Candu type nuclear reactor pressure tubes suffer deformations during operation. This are consequences of irradiation growth and creep. By means of a computer code which takes into account the material microstructure, the above mentioned deformations are calculated, and results are compared with corresponding values measured at Embalse nuclear power plant. The calculations make explicit inclusion of intergranular stresses caused by an isotropy in the material. (author). 1 ref
Deformation of vanadium and niobium during hydrogenation
Energy Technology Data Exchange (ETDEWEB)
Geld, P.V.; Kats, M.IA.; Spivak, L.V.
1986-01-01
The deformation behavior of polycrystalline vanadium and niobium during hydrogenation is investigated experimentally using a torsional pendulum to load 0.5-mm-diameter, 80-mm-long wire specimens. It is found that under conditions of isothermal hydrogenation, the macrodeformation of the V and Nb specimens is determined by the contributions of the following two components: deformation due to changes in the shear modulus of the system metal-hydrogen and deformation due to the oriented growth of the hydride phase in an applied stress field. 9 references.
Localization of deformation and fracture of zirconium alloys
International Nuclear Information System (INIS)
The report consists of two parts. The first explains the theory of the localization of deformation in deformation zones and the theory of localized necking of thin sheets and their relation to the localization of damage and development of cracks. Part two deals with the qualitative and quantitative analysis of the behavior of Zr alloys. A bifurcation analysis is used for three variant constitutive equations to verify the hypothesis that predicted values of critical deformation in a corrosive medium represent deformations to fracture. The relation is defined between fracture toughness in a corrosive medium and critical deformation for the localization of deformation in deformation zones. The analysis of the processes of corrosion cracking of cladding tubes which had been without defects in the initial state, and of the development of cracks in the corrosive medium during planar deformation showed that there exists a close relation between mechanical characteristics and the development and growth of cracks. (author). 7 figs., 50 refs
Deformation aspects of time dependent fracture
International Nuclear Information System (INIS)
For all metallic materials, particularly at elevated temperatures, deformation plays an important role in fracture. On the macro-continuum level, the inelastic deformation behavior of the material determines how stress is distributed in the body and thus determines the driving force for fracture. At the micro-continuum level, inelastic deformation alters the elastic stress singularity at the crack tip and so determines the local environment in which crack advance takes place. At the microscopic and mechanistic level, there are many possibilities for the mechanisms of deformation to be related to those for crack initiation and growth. At elevated temperatures, inelastic deformation in metallic systems is time dependent so that the distribution of stress in a body will vary with time, affecting conditions for crack initiation and propagation. Creep deformation can reduce the tendency for fracture by relaxing the stresses at geometric stress concentrations. It can also, under suitable constraints, cause a concentration of stresses at specific loading points as a result of relaxation elsewhere in the body. A combination of deformation and unequal heating, as in welding, can generate large residual stress which cannot be predicted from the external loads on the body. Acceleration of deformation by raising the temperature can be an effective way to relieve such residual stresses
Deformable Nanolaminate Optics
Energy Technology Data Exchange (ETDEWEB)
Olivier, S S; Papavasiliou, A P; Barbee, T W; Miles, R R; Walton, C C; Cohn, M B; Chang, K
2006-05-12
We are developing a new class of deformable optic based on electrostatic actuation of nanolaminate foils. These foils are engineered at the atomic level to provide optimal opto-mechanical properties, including surface quality, strength and stiffness, for a wide range of deformable optics. We are combining these foils, developed at Lawrence Livermore National Laboratory (LLNL), with commercial metal processing techniques to produce prototype deformable optics with aperture sizes up to 10 cm and actuator spacing from 1 mm to 1 cm and with a range of surface deformation designed to be as much as 10 microns. The existing capability for producing nanolaminate foils at LLNL, coupled with the commercial metal processing techniques being used, enable the potential production of these deformable optics with aperture sizes of over 1 m, and much larger deformable optics could potentially be produced by tiling multiple deformable segments. In addition, based on the fabrication processes being used, deformable nanolaminate optics could potentially be produced with areal densities of less than 1 kg per square m for applications in which lightweight deformable optics are desirable, and deformable nanolaminate optics could potentially be fabricated with intrinsically curved surfaces, including aspheric shapes. We will describe the basic principles of these devices, and we will present details of the design, fabrication and characterization of the prototype deformable nanolaminate optics that have been developed to date. We will also discuss the possibilities for future work on scaling these devices to larger sizes and developing both devices with lower areal densities and devices with curved surfaces.
Deformed Dynamics of Q-Deformed Systems
International Nuclear Information System (INIS)
Quantum algebras have been the subject of an intensively research in the last years. Particularly, after the works of Macfarlane and Biedenharn on the q-deformed oscillators, a great effort has been devoted to the application and generalization of q-deformed systems in chemistry and physics. In quantum optics, q-bosons have been used to generalized fundamental models such as, the Jaynes-Cummings and Dicke models. Besides, using generalized deformed oscillators several versions of the Jaynes-Cummings Hamiltonian have found a unified description. In the present work, we study the dynamical properties of q-deformed oscillators and their relationship to the anharmonic oscillators by means of a Lie-algebraic approach. In doing so, we find that an infinite dimensional set of 'q-deformed relevant operators' close a 'partial q-deformed Lie algebra' under commutation with the Arik-Coon Hamiltonian. We show that the dynamics of the s?stem can be described in terms of the multi commutator of the type [H,... , [H, 0] . . .]. Eve also obtain, that the multi commutator can be expressed for q > 1 as an operator average with respect to the ('Binomial distribution' which depends on[g on the deformation parameter q, and for the general case (i.e. q - R) as a 'power law'. As a consequence of the power law dependence, we find that the dynamics of the infinite-dimensional q-deformed Lie-algebra scale, i.e. the temporal evolution for the whole set of relevant operators collapse on a single curve. We calculate and analyze, the temporal evolution of the set of relevant operators for the q-deformed and the anharmonic oscillator when the initial conditions are a q-coherent and coherent states respectively. We obtain that the dynamics of both models is governed by a weighted average with respect to the 'q-deformed Poisson' and the 'standard Poisson' distributions respectively. Finally, we find the conditions under which the dynamics of the relevant operators of both oscillators are
Deformations and Nonlinear Systems
Man'ko, V. I.; Marmo, G.; F. Zaccaria
1997-01-01
The q-deformation of harmonic oscillators is shown to lead to q-nonlinear vibrations. The examples of q-nonlinearized wave equation and Schr\\"odinger equation are considered. The procedure is generalized to broader class of nonlinearities related to other types of deformations. The nonlinear noncanonical transforms used in the deformation procedure are shown to preserve in some cases the linear dynamical equations, for instance, for the harmonic oscillators. The nonlinear coherent states and ...
Indian Academy of Sciences (India)
Ramaswamy Jaganathan; Sudeshna Sinha
2005-03-01
Motivated by studies on -deformed physical systems related to quantum group structures, and by the elements of Tsallis statistical mechanics, the concept of -deformed nonlinear maps is introduced. As a specific example, a -deformation procedure is applied to the logistic map. Compared to the canonical logistic map, the resulting family of -logistic maps is shown to have a wider spectrum of interesting behaviours, including the co-existence of attractors – a phenomenon rare in one-dimensional maps.
Fluctuations as stochastic deformation
Kazinski, P. O.
2008-04-01
A notion of stochastic deformation is introduced and the corresponding algebraic deformation procedure is developed. This procedure is analogous to the deformation of an algebra of observables like deformation quantization, but for an imaginary deformation parameter (the Planck constant). This method is demonstrated on diverse relativistic and nonrelativistic models with finite and infinite degrees of freedom. It is shown that under stochastic deformation the model of a nonrelativistic particle interacting with the electromagnetic field on a curved background passes into the stochastic model described by the Fokker-Planck equation with the diffusion tensor being the inverse metric tensor. The first stochastic correction to the Newton equations for this system is found. The Klein-Kramers equation is also derived as the stochastic deformation of a certain classical model. Relativistic generalizations of the Fokker-Planck and Klein-Kramers equations are obtained by applying the procedure of stochastic deformation to appropriate relativistic classical models. The analog of the Fokker-Planck equation associated with the stochastic Lorentz-Dirac equation is derived too. The stochastic deformation of the models of a free scalar field and an electromagnetic field is investigated. It turns out that in the latter case the obtained stochastic model describes a fluctuating electromagnetic field in a transparent medium.
Arzano, Michele
2016-01-01
We construct discrete symmetry transformations for deformed relativistic kinematics based on group valued momenta. We focus on the specific example of kappa-deformations of the Poincare algebra with associated momenta living on (a sub-manifold of) de Sitter space. Our approach relies on the description of quantum states constructed from deformed kinematics and the observable charges associated with them. The results we present provide the first step towards the analysis of experimental bounds on the deformation parameter kappa to be derived via precision measurements of discrete symmetries and CPT.
Deformable Simplicial Complexes
DEFF Research Database (Denmark)
Misztal, Marek Krzysztof
In this dissertation we present a novel method for deformable interface tracking in 2D and 3D|deformable simplicial complexes (DSC). Deformable interfaces are used in several applications, such as fluid simulation, image analysis, reconstruction or structural optimization. In the DSC method, the...... triangles/tetrahedra marked as outside from those marked as inside. Such an approach allows for robust topological adaptivity. Among other advantages of the deformable simplicial complexes there are: space adaptivity, ability to handle and preserve sharp features, possibility for topology control. We...
Arzano, Michele; Kowalski-Glikman, Jerzy
2016-09-01
We construct discrete symmetry transformations for deformed relativistic kinematics based on group valued momenta. We focus on the specific example of κ-deformations of the Poincaré algebra with associated momenta living on (a sub-manifold of) de Sitter space. Our approach relies on the description of quantum states constructed from deformed kinematics and the observable charges associated with them. The results we present provide the first step towards the analysis of experimental bounds on the deformation parameter κ to be derived via precision measurements of discrete symmetries and CPT.
Mechanisms of deformation and of recrystallization of imperfect uranium monocrystals
International Nuclear Information System (INIS)
The various means by which plastic deformations by slip, twinning or kinking are produced by tension of imperfect α uranium single crystals prepared by a β → α phase change, have been studied by X-rays and micrographic examination. Depending on the crystallographic orientation with respect to the direction of the applied tension, and depending on the magnitude of the change in length, the crystals are deformed either preferentially according to a single mechanism, for example twinning, or simultaneously according to two or three mechanisms. The results of a subsequent annealing of the deformed single in the α phase are studied with respect to the deformation mechanisms. In the case of a deformation due primarily to (010) [100], (011) [100] or (110) [001] sliding, there occurs recrystallization by crystal growth selectivity. If the deformation occurs via deformation bands, there is recrystallization by 'oriented nucleation'. The crystals deformed preponderantly by twinning give on recrystallization perfect crystals having optimum dimensions and having orientational characteristics closely related to those of the original crystal. Finally are discussed some criteria relating to the geometry and the dynamics with a view to explaining the occurrence of such and such a deformation mechanism of a single crystal with a given orientation. This study, in conclusion, must help to define the best conditions (crystalline orientation and process of deformation) which will promote the growth of large, perfect, single crystals. (author)
Deformations of algebroid stacks
DEFF Research Database (Denmark)
Bressler, Paul; Gorokhovsky, Alexander; Nest, Ryszard; Tsygan, Boris
2011-01-01
In this paper we consider deformations of an algebroid stack on an étale groupoid. We construct a differential graded Lie algebra (DGLA) which controls this deformation theory. In the case when the algebroid is a twisted form of functions we show that this DGLA is quasiisomorphic to the twist of ...
Deformation Behavior of Human Dentin under Uniaxial Compression
Dmitry Zaytsev; Sergey Grigoriev; Peter Panfilov
2012-01-01
Deformation behavior of a human dentin under compression including size and rate effects is studied. No difference between mechanical properties of crown and root dentin is found. It is mechanically isotropic high elastic and strong hard tissue, which demonstrates considerable plasticity and ability to suppress a crack growth. Mechanical properties of dentin depend on a shape of samples and a deformation rate.
Deformation mechanisms in experimentally deformed Boom Clay
Desbois, Guillaume; Schuck, Bernhard; Urai, Janos
2016-04-01
Bulk mechanical and transport properties of reference claystones for deep disposal of radioactive waste have been investigated since many years but little is known about microscale deformation mechanisms because accessing the relevant microstructure in these soft, very fine-grained, low permeable and low porous materials remains difficult. Recent development of ion beam polishing methods to prepare high quality damage free surfaces for scanning electron microscope (SEM) is opening new fields of microstructural investigation in claystones towards a better understanding of the deformation behavior transitional between rocks and soils. We present results of Boom Clay deformed in a triaxial cell in a consolidated - undrained test at a confining pressure of 0.375 MPa (i.e. close to natural value), with σ1 perpendicular to the bedding. Experiments stopped at 20 % strain. As a first approximation, the plasticity of the sample can be described by a Mohr-Coulomb type failure envelope with a coefficient of cohesion C = 0.117 MPa and an internal friction angle ϕ = 18.7°. After deformation test, the bulk sample shows a shear zone at an angle of about 35° from the vertical with an offset of about 5 mm. We used the "Lamipeel" method that allows producing a permanent absolutely plane and large size etched micro relief-replica in order to localize and to document the shear zone at the scale of the deformed core. High-resolution imaging of microstructures was mostly done by using the BIB-SEM method on key-regions identified after the "Lamipeel" method. Detailed BIB-SEM investigations of shear zones show the following: the boundaries between the shear zone and the host rock are sharp, clay aggregates and clastic grains are strongly reoriented parallel to the shear direction, and the porosity is significantly reduced in the shear zone and the grain size is smaller in the shear zone than in the host rock but there is no evidence for broken grains. Comparison of microstructures
Neves, J C S
2015-01-01
In this work, we have deformed regular black holes which possess a general mass term described by a function which generalizes the Bardeen and Hayward mass terms. Using linear constraints in the energy-momentum tensor, the solutions are either regular or singular. That is, with this approach, it is possible to generate singular black holes from regular black holes and vice versa. Moreover, contrary to the Bardeen and Hayward regular solutions, the regular deformed metrics may violate the weak energy condition despite the presence of the spherical symmetry. Some comments on accretion of deformed black holes in cosmological scenarios are made.
Extremely deformable structures
2015-01-01
Recently, a new research stimulus has derived from the observation that soft structures, such as biological systems, but also rubber and gel, may work in a post critical regime, where elastic elements are subject to extreme deformations, though still exhibiting excellent mechanical performances. This is the realm of ‘extreme mechanics’, to which this book is addressed. The possibility of exploiting highly deformable structures opens new and unexpected technological possibilities. In particular, the challenge is the design of deformable and bi-stable mechanisms which can reach superior mechanical performances and can have a strong impact on several high-tech applications, including stretchable electronics, nanotube serpentines, deployable structures for aerospace engineering, cable deployment in the ocean, but also sensors and flexible actuators and vibration absorbers. Readers are introduced to a variety of interrelated topics involving the mechanics of extremely deformable structures, with emphasis on ...
Directory of Open Access Journals (Sweden)
Mohd E. Rasul
2015-12-01
Full Text Available Sprengel shoulder is a rare congenital deformity of one or both scapulae that is usually detected at birth. It occurs due to failure of the scapula to descend during intrauterine development. Although the deformity appears randomly most of the time, familial cases have been reported. Sprengel shoulder is often associated with Klippel-Feil syndrome and other congenital skeletal deformities. Anteroposterior X-ray imaging can accurately diagnose Sprengel deformity. However, computed tomography and magnetic resonance scans with three-dimensional reconstruction are nowadays used in everyday practice in order to diagnose concomitant abnormalities, study in detail the anatomy of the affected shoulder(s, and plan appropriate management. We present here our imaging experience from one pediatric case with Sprengel shoulder and take the opportunity to discuss this rare entity, which is, nevertheless, the commonest congenital defect of the scapula. [Int J Res Med Sci 2015; 3(12.000: 3869-3871
Canonical Infinitesimal Deformations
Ran, Ziv
1998-01-01
This paper gives a canonical construction, in terms of additive cohomological functors, of the universal formal deformation of a compact complex manifold without vector fields (more generally of a faithful $g$-module, where $g$ is a sheaf of Lie algebras without sections). The construction is based on a certain (multivariate) Jacobi complex $J(g)$ associatd to $g$: indeed ${\\mathbb C}\\oplus {\\mathbb H}^0(J(g))^*$ is precisely the base ring of the universal deformation.
Kustas, A. B.; Sagapuram, D.; Chandrasekar, S.; Trumble, K. P.
2015-04-01
Machining is used as a deformation technique to impose large shear strains (γ ˜ 2) in a commercial Fe-4%Si alloy. The partial and {110} - fiber texture components are generated throughout the as-deformed microstructure, which is expected of BCC metals deformed in simple shear. Using an annealing schedule similar to that in the commercial rolling process, samples retain the deformation texture, consistent with a continuous-type recrystallization mechanism. Fine-grained annealed samples reveal two different partial fiber orientations, one of which becomes the dominate texture, following the high-temperature growth treatment. The mechanisms of texture evolution and implications for texture control in the machining-based process are discussed.
Operating limits for subassembly deformation in EBR-II
International Nuclear Information System (INIS)
The deformation of a subassembly in response to the core environment is frequently the life limiting factor for that component in an LMFBR. Deformation can occur as diametral and axial growth or bowing of the subassembly. Such deformation has caused several handling problems in both the core and the storage basket of EBR-II and may also have contributed to reactivity anomalies during reactor operation. These problems generally affect plant availability but the reactivity anomalies could lead to a potential safety hazard. Because of these effects the deformation mechanisms must be understood and modeled. Diametral and axial growth of subassembly ducts in EBR-II is due to swelling and creep and is a function of temperature, neutron fluence and stress. The source of stress in a duct is the hydraulic pressure difference across the wall. By coupling the calculated subassembly growth rate to the available clearance in the core or storage basket a limiting neutron fluence, or exposure, can be established
Analysis of cavitation and its effects on superplastic deformation
Directory of Open Access Journals (Sweden)
H. Tan
2007-12-01
Full Text Available Purpose: To study the effects of cavitation on the superplastic deformation using finite element method.Design/methodology/approach: Using consitututive equations for superplastic deformation, and taking into account the effects of grain growth and cavitation growth, Zn-Al and LY12CZ alloys are used for simulations to show effects of m values, elongation-to-failure values, percentage cavities and effects of imposed hydrostatic pressure during superplastic forming processes.Findings: During superplastic deformation, cavitation damage increases with the increase in strain. For high strain rate sensitivity, necking develops which leads to final fracture; whereas for low strain strain rate sensitivity, the final fracture is due to cavitation growth.Research limitations/implications: The effects of material parameters and deformation damage on the superplastic deformation process are numerically analyzed, and the means to control cavitation growth is discussed.Originality/value: A three dimensional viscoplastic finite element programe, taking into account of microstructural mechanisms, such as test temperature and cavity growth has been developed for superplastic deformation.
Kaissi, Ali Al; Farr, Sebastian; Ganger, Rudolf; Hofstaetter, Jochen G; Klaushofer, Klaus; Grill, Franz
2013-01-01
Angular deformities of the lower limbs are a common clinical problem encountered in pediatric orthopaedic practices particularly in patients with osteochondrodysplasias. The varus deformity is more common than the valgus deformity in achondroplasia and hypochondroplasia patients because of the unusual growth of the fibulae than that of the tibiae. We retrospectively reviewed six patients (four patients with achondroplasia and two patients with hypochondroplsia) with relevant limb deformities ...
Vaporization of Deforming Droplets
Wang, Yanxing; Chen, Xiaodong; Ma, Dongjun; Yang, Vigor
2012-11-01
Droplet deformation is one of the most important factors influencing the evaporation rate. In the present study, high-fidelity numerical simulations of single evaporating droplets with deformation are carried out over a wide range of the Reynolds and Weber numbers. The formulation is based on a complete set of conservation equations for both the liquid and surrounding gas phases. A modified volume-of-fluid (VOF) technique that takes into account heat and mass transfer is used to track the behavior of the liquid/gas interface. Special attention is given to the property conservation, which can be realized by using an iterative algorithm that enforces a divergence constraint in cells containing the interface. The effect of the ambient flow on droplet dynamics and evaporation are investigated systematically. Various underlying mechanisms dictating the droplet characteristics in different deformation regimes are identified. Correlations for the droplet evaporation rate are established in terms of the Reynolds and Weber numbers.
Autogenous Deformation of Concrete
DEFF Research Database (Denmark)
Autogenous deformation of concrete can be defined as the free deformation of sealed concrete at a constant temperature. A number of observed problems with early age cracking of high-performance concretes can be attributed to this phenomenon. During the last 10 years , this has led to an increased...... focus on autogenous deformation both within concrete practice and concrete research. Since 1996 the interest has been significant enough to hold international, yearly conferences entirely devoted to this subject. The papers in this publication were presented at two consecutive half-day sessions at the...... American Concrete Institute’s Fall Convention in Phoenix, Arizona, October 29, 2002. All papers have been reviewed according to ACI rules. This publication, as well as the sessions, was sponsored by ACI committee 236, Material Science of Concrete. The 12 presentations from 8 different countries indicate...
Crustal deformation and earthquakes
Cohen, S. C.
1984-01-01
The manner in which the Earth's surface deforms during the cycle of stress accumulation and release along major faults is investigated. In an investigation of the crustal deformation associated with a thin channel asthenosphere displacements are reduced from those computed for a half space asthenosphere. A previous finding by other workers that displacements are enhanced when flow is confined to a thin channel is based on several invalid approximations. The major predictions of the finite element model are that the near field postseismic displacements and strain rates are less than those for a half space asthenosphere and that the postseismic strain rates at intermediate distances are greater (in magnitude). The finite width of the asthenosphere ceases to have a significant impact on the crustal deformation pattern when its magnitude exceeds about three lithosphere thicknesses.
Agrawal, Ashish; Agrawal, Rahul; Singh, Rajat; Agrawal, Romi; Agrawal, Seema
2014-01-01
Endogenous erythroid colony (EEC) syndrome comprise of three cardinal features, i.e. ectrodactyly, ectodermal dysplasia and cleft lip. EEC itself has three different forms. Ectrodactyly (absence of one or more digits) can be present with clefting in the proximal portion of hand or foot known as split hand foot malformation (SHFM) or lobster claw deformity. SHFM can be of four types depending upon the different responsible chromosomal loci. SHFM-4 can be present as pure limb malformation (non-syndromic form). In this article, describes a rare case report of lobster claw deformity patient. PMID:24992861
Directory of Open Access Journals (Sweden)
Ashish Agrawal
2014-01-01
Full Text Available Endogenous erythroid colony (EEC syndrome comprise of three cardinal features, i.e. ectrodactyly, ectodermal dysplasia and cleft lip. EEC itself has three different forms. Ectrodactyly (absence of one or more digits can be present with clefting in the proximal portion of hand or foot known as split hand foot malformation (SHFM or lobster claw deformity. SHFM can be of four types depending upon the different responsible chromosomal loci. SHFM-4 can be present as pure limb malformation (non-syndromic form. In this article, describes a rare case report of lobster claw deformity patient.
Joining by plastic deformation
DEFF Research Database (Denmark)
Mori, Ken-ichiro; Bay, Niels; Fratini, Livan;
2013-01-01
As the scale and complexity of products such as aircraft and cars increase, demand for new functional processes to join mechanical parts grows. The use of plastic deformation for joining parts potentially offers improved accuracy, reliability and environmental safety as well as creating opportuni......As the scale and complexity of products such as aircraft and cars increase, demand for new functional processes to join mechanical parts grows. The use of plastic deformation for joining parts potentially offers improved accuracy, reliability and environmental safety as well as creating...
Nail Deformities and Injuries.
Tucker, James Rory J
2015-12-01
A variety of nail deformities commonly presents in the primary care office. An understanding of nail anatomy coupled with inspection of the nails at routine office visits can reveal undetected disorders. Some problems are benign, and treatment should be attempted by the primary care provider, such as onychomycosis, paronychia, or ingrown toenails. For conditions such as benign melanonychia, longitudinal ridges, isolated Beau lines, and onycholysis, clinicians may offer reassurance to patients who are concerned about the change in their nails. For deformities such as early pterygium or clubbing, a thorough evaluation and referral to an appropriate specialist may be warranted. PMID:26612379
Deformation in nanocrystalline metals
Directory of Open Access Journals (Sweden)
Helena Van Swygenhoven
2006-05-01
Full Text Available It is now possible to synthesize polycrystalline metals made up of grains that average less than 100 nm in size. Such nanocrystalline metals contain a significant volume fraction of interfacial regions separated by nearly perfect crystals. The small sizes involved limit the conventional operation of dislocation sources and thus a fundamental question arises: how do these materials deform plastically? We review the current views on deformation mechanisms in nanocrystalline, face-centered cubic metals based on insights gained by atomistic computer simulations. These insights are discussed with reference to recent striking experimental observations that can be compared with predictions made by the simulations.
Deforming Geometric Transitions
Rossi, Michele
2013-01-01
After a quick review of the wild structure of the complex moduli space of Calabi-Yau threefolds and the role of geometric transitions in this context (the Calabi-Yau web) the concept of "deformation equivalence" for geometric transitions is introduced to understand the arrows of the Gross-Reid Calabi-Yau web as deformation-equivalence classes of geometric transitions. Then the focus will be on some results and suitable examples to understand under which conditions it is possible to get "simpl...
Advances in the theory of deformation and recrystallization texture formation
Energy Technology Data Exchange (ETDEWEB)
Smallman, R.E. (School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT (United Kingdom)); Lee, C.S. (School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT (United Kingdom))
1994-08-15
The development of the formation of texture in both rolled and annealed f.c.c. metals has been reviewed and limitation in the present understanding identified. Special attention is given to the problems of the deformation texture transition in f.c.c. materials and to the development of cube texture during recrystallization. Inadequacies in the current deformation models are discussed and recent experimental results based on metallographic studies of highly deformed metals presented. The work demonstrates the importance of deformation banding as a mechanism of deformation which significantly influences both the development of the deformation texture and the subsequent recrystallization process. Consideration of the additional deformation modes enables a new deformation model to be developed which gives results in better agreement with experiment. Experiments on cube texture formation in relation to previous recrystallization studies and to the role played by both the oriented-nucleation and the oriented-growth theories in recrystallization is briefly reviewed. Recent work on the role of deformation banding in the formation of cube-oriented volumes having a special orientation relationship with their neighbours is presented, leading to a generalized theory of the cube recrystallization texture formation. ((orig.))
Universal deformation formulas
Czech Academy of Sciences Publication Activity Database
Remm, E.; Markl, Martin
2015-01-01
Roč. 43, č. 11 (2015), s. 4711-4734. ISSN 0092-7872 Institutional support: RVO:67985840 Keywords : algebra * deformation * twisting Subject RIV: BA - General Mathematics Impact factor: 0.388, year: 2014 http://www.tandfonline.com/doi/abs/10.1080/00927872.2014.949729
Marginally Deformed Starobinsky Gravity
DEFF Research Database (Denmark)
Codello, A.; Joergensen, J.; Sannino, Francesco;
2015-01-01
We show that quantum-induced marginal deformations of the Starobinsky gravitational action of the form $R^{2(1 -\\alpha)}$, with $R$ the Ricci scalar and $\\alpha$ a positive parameter, smaller than one half, can account for the recent experimental observations by BICEP2 of primordial tensor modes....
Diffeomorphic Statistical Deformation Models
DEFF Research Database (Denmark)
Hansen, Michael Sass; Hansen, Mads/Fogtman; Larsen, Rasmus
2007-01-01
manifold and that the distance between two deformations are given by the metric introduced by the L2-norm in the parameter space. The chosen L2-norm is shown to have a clear and intuitive interpretation on the usual nonlinear manifold. Our model is validated on a set of MR images of corpus callosum with...
Nienhuys, Han-Wen
2003-01-01
Virtual reality simulations of surgical procedures allow such procedures to be practiced on computers instead of patients and test-animals. The core of such a system is a soft tissue simulation, that has to react very quickly but be realistic at the same time. This thesis discusses how deformable
Formation and subdivision of deformation structures during plastic deformation
DEFF Research Database (Denmark)
Jakobsen, B.; Poulsen, H.F.; Lienert, U.;
2006-01-01
of individual, deeply embedded dislocation structures. During tensile deformation of pure copper, dislocation-free regions were identified. They showed an unexpected intermittent dynamics, for example, appearing and disappearing with proceeding deformation and even displaying transient splitting...
Strengthening of HSLA steels by cool deformation
International Nuclear Information System (INIS)
In microalloyed steels, the refinement of ferrite grains together with a controlled amount of precipitation has key roles in the mechanical properties improvement. Applying small amounts of deformation, at very low hot working temperatures (i.e. coiling temperature), in the ferrite region (i.e. cool deformation) has an appreciable strengthening effect via controlling the final microstructure of the steel. One of the microstructural effects is thought to be the much finer and more uniformly dispersed precipitates in the steel matrix. In the present study, the effects of Nb and Cu on mechanical properties and corresponding microstructures in steels with different levels of cool deformation are investigated. The mechanical properties of the samples were determined using the shear punch test and the microstructure was examined by scanning and transmission electron microscopy. Thermodynamic simulations with FactSage were done to further analyze the precipitation possibility of different elements. It has been found that these alloying elements respond very well to cool deformation, with the strength being highest in steels containing both Nb and Cu. However, a cool deformation effect in the non-Nb and Cu bearing steel is also observed. In all cases, it was confirmed that precipitation plays a key role in the effect of cool deformation, with much of the precipitation taking place dynamically. Nevertheless, static processes also seem to have a measurable effect on room temperature properties. Even low amounts of copper (e.g. ∼0.4 wt%) can contribute to strengthening of the steel. The Cu addition is found to affect the mechanical properties by affecting the precipitation and growth of Nb compounds.
Strengthening of HSLA steels by cool deformation
Energy Technology Data Exchange (ETDEWEB)
Fatehi, A., E-mail: arya.fatehi@gmail.com [Department of Mining, Metals and Materials Engineering, McGill University, 3610 University Street, Montreal, QC, H3A 2B2 (Canada); Calvo, J.; Elwazri, A.M.; Yue, S. [Department of Mining, Metals and Materials Engineering, McGill University, 3610 University Street, Montreal, QC, H3A 2B2 (Canada)
2010-06-25
In microalloyed steels, the refinement of ferrite grains together with a controlled amount of precipitation has key roles in the mechanical properties improvement. Applying small amounts of deformation, at very low hot working temperatures (i.e. coiling temperature), in the ferrite region (i.e. cool deformation) has an appreciable strengthening effect via controlling the final microstructure of the steel. One of the microstructural effects is thought to be the much finer and more uniformly dispersed precipitates in the steel matrix. In the present study, the effects of Nb and Cu on mechanical properties and corresponding microstructures in steels with different levels of cool deformation are investigated. The mechanical properties of the samples were determined using the shear punch test and the microstructure was examined by scanning and transmission electron microscopy. Thermodynamic simulations with FactSage were done to further analyze the precipitation possibility of different elements. It has been found that these alloying elements respond very well to cool deformation, with the strength being highest in steels containing both Nb and Cu. However, a cool deformation effect in the non-Nb and Cu bearing steel is also observed. In all cases, it was confirmed that precipitation plays a key role in the effect of cool deformation, with much of the precipitation taking place dynamically. Nevertheless, static processes also seem to have a measurable effect on room temperature properties. Even low amounts of copper (e.g. {approx}0.4 wt%) can contribute to strengthening of the steel. The Cu addition is found to affect the mechanical properties by affecting the precipitation and growth of Nb compounds.
Deformation quantization of bosonic strings
International Nuclear Information System (INIS)
Deformation quantization of bosonic strings is considered. We show that the light-cone gauge is the most convenient classical description to perform the quantization of bosonic strings in the deformation quantization formalism. Similar to the field theory case, the oscillator variables greatly facilitates the analysis. The mass spectrum, propagators and the Virasoro algebra are finally described within this deformation quantization scheme. (author)
Rotational Deformation of Neutron Stars
Institute of Scientific and Technical Information of China (English)
WEN De-Hua; CHEN Wei; LIU Liang-Gang
2005-01-01
@@ The rotational deformations of two kinds of neutron stars are calculated by using Hartle's slow-rotation formulism.The results show that only the faster rotating neutron star gives an obvious deformation. For the slow rotating neutron star with a period larger than hundreds of millisecond, the rotating deformation is very weak.
Cosmetic and Functional Nasal Deformities
... nasal complaints. Nasal deformity can be categorized as “cosmetic” or “functional.” Cosmetic deformity of the nose results in a less ... taste , nose bleeds and/or recurrent sinusitis . A cosmetic or functional nasal deformity may occur secondary to ...
[Babies with cranial deformity].
Feijen, Michelle M W; Claessens, Edith A W M Habets; Dovens, Anke J Leenders; Vles, Johannes S; van der Hulst, Rene R W J
2009-01-01
Plagiocephaly was diagnosed in a baby aged 4 months and brachycephaly in a baby aged 5 months. Positional or deformational plagio- or brachycephaly is characterized by changes in shape and symmetry of the cranial vault. Treatment options are conservative and may include physiotherapy and helmet therapy. During the last two decades the incidence of positional plagiocephaly has increased in the Netherlands. This increase is due to the recommendation that babies be laid on their backs in order to reduce the risk of sudden infant death syndrome. We suggest the following: in cases of positional preference of the infant, referral to a physiotherapist is indicated. In cases of unacceptable deformity of the cranium at the age 5 months, moulding helmet therapy is a possible treatment option. PMID:19857299
Probing deformed quantum commutators
Rossi, Matteo A. C.; Giani, Tommaso; Paris, Matteo G. A.
2016-07-01
Several quantum gravity theories predict a minimal length at the order of magnitude of the Planck length, under which the concepts of space and time lose their physical meaning. In quantum mechanics, the insurgence of such a minimal length can be described by introducing a modified position-momentum commutator, which in turn yields a generalized uncertainty principle, where the uncertainty on position measurements has a lower bound. The value of the minimal length is not predicted by theories and must be estimated experimentally. In this paper, we address the quantum bound to the estimability of the minimal uncertainty length by performing measurements on a harmonic oscillator, which is analytically solvable in the deformed algebra induced by the deformed commutation relations.
Deformed supersymmetric mechanics
International Nuclear Information System (INIS)
Motivated by a recent interest in curved rigid supersymmetries, we construct a new type of N = 4, d = 1 supersymmetric systems by employing superfields defined on the cosets of the supergroup SU(2|1). The relevant worldline supersymmetry is a deformation of the standard N = 4, d = 1 supersymmetry by a mass parameter m. As instructive examples we consider at the classical and quantum levels the models associated with the supermultiplets (1,4,3) and (2,4,2) and find out interesting interrelations with some previous works on nonstandard d = 1 supersymmetry. In particular, the d = 1 systems with 'weak supersymmetry' are naturally reproduced within our SU(2|1) superfield approach as a subclass of the (1,4,3) models. A generalization to the N = 8, d = 1 case implies the supergroup SU(2|2) as a candidate deformed worldline supersymmetry
Ashish Agrawal; Rahul Agrawal; Rajat Singh; Romi Agrawal; Seema Agrawal
2014-01-01
Endogenous erythroid colony (EEC) syndrome comprise of three cardinal features, i.e. ectrodactyly, ectodermal dysplasia and cleft lip. EEC itself has three different forms. Ectrodactyly (absence of one or more digits) can be present with clefting in the proximal portion of hand or foot known as split hand foot malformation (SHFM) or lobster claw deformity. SHFM can be of four types depending upon the different responsible chromosomal loci. SHFM-4 can be present as pure limb malformation (non-...
Deformations of fractured rock
International Nuclear Information System (INIS)
Results of the DBM and FEM analysis in this study indicate that a suitable rock mass for repository of radioactive waste should be moderately jointed (about 1 joint/m2) and surrounded by shear zones of the first order. This allowes for a gentle and flexible deformation under tectonic stresses and prevent the development of large cross-cutting failures in the repository area. (author)
Institute of Scientific and Technical Information of China (English)
GAO Lin; ZHANG GuoXin; LAI YuKun
2012-01-01
Shape deformation is a fundamental tool in geometric modeling.Existing methods consider preserving local details by minimizing some energy functional measuring local distortions in the L2 norm.This strategy distributes distortions quite uniformly to all the vertices and penalizes outliers.However,there is no unique answer for a natural deformation as it depends on the nature of the objects.Inspired by recent sparse signal reconstruction work with non L2 norm,we introduce general Lp norms to shape deformation; the positive parameter p provides the user with a flexible control over the distribution of unavoidable distortions.Compared with the traditional L2 norm,using smaller p,distortions tend to be distributed to a sparse set of vertices,typically in feature regions,thus making most areas less distorted and structures better preserved. On the other hand,using larger p tends to distribute distortions more evenly across the whole model.This flexibility is often desirable as it mimics objects made up with different materials.By specifying varying p over the shape,more flexible control can be achieved.We demonstrate the effectiveness of the proposed algorithm with various examples.
Supertransvectants, cohomology, and deformations
Ben Fraj, Nizar; Laraiedh, Ismail; Omri, Salem
2013-02-01
Over the (1, N)-dimensional real superspace, N = 2, 3, we classify {osp}(N|2)-invariant binary differential operators acting on the superspaces of weighted densities, where {osp}(N|2) is the orthosymplectic Lie superalgebra. This result allows us to compute the first differential {osp}(N|2)-relative cohomology of the Lie superalgebra K(N) of contact vector fields with coefficients in the superspace of linear differential operators acting on the superspaces of weighted densities. We classify generic formal {osp}(3|2)-trivial deformations of the K(3)-module structure on the superspaces of symbols of differential operators. We prove that any generic formal {osp}(3|2)-trivial deformation of this K(3)-module is equivalent to its infinitesimal part. This work is the simplest generalization of a result by the first author et al. [Basdouri, I., Ben Ammar, M., Ben Fraj, N., Boujelbene, M., and Kammoun, K., "Cohomology of the Lie superalgebra of contact vector fields on {K}^{1|1} and deformations of the superspace of symbols," J. Nonlinear Math. Phys. 16, 373 (2009), 10.1142/S1402925109000431].
EFFECT OF UNEQUAL DEFORMATION IN DEVELOPMENT OF ADVANCED PLASTIC PROCESSING TECHNOLOGIES
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
An effect of unequal deformation in development of advanced plastic processing technologies is researched by studying an in-plane bending process of strip metal under unequal compressing. The research results show the following: If appropriately controlled, unequal plastic deformation can play an important role not only in the improvement of quality of parts obtained by plastic processing technologies, but also in the development of new processes for advanced plastic working technologies. A coordinated growth of unequal plastic deformation can develop the deformation potentiality of material to the full. The degree of unequal plastic deformation can be used as bases for optimization design of processes and dies of plastic forming.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The stress-induced phase transformation in incompressible materials and the interfacial stability of multi-phase deformation were studied. The existence of multi-phase deformation was determined through exploring whether the material would lose the strong ellipticity at some deformation gradient.Then, according to the stability criterion which is based on a quasi-static approach, the stability of the multi-phase deformation in incompressible materials was investigated by studying the growth/decay behaviour of the interface in the undeformed configuration when it is perturbed. At last, the way to define multi-phase deformation in incompressible materials was concluded and testified by a corresponding numerical example.
Deformation enhanced decarburization of WC-Co
International Nuclear Information System (INIS)
The paper describes an unusual transformation that takes place only within the deformed region of identations. Under a suitable ambient temperature decarburization of cemented WC-Co on annealing is enhanced by prior localized deformation. Within individual WC grains, plate-like growth of a mixed carbide (either Co3W3C or Co6W6C) occurs preferentially. On some occasions intrusion of the substoichiometric carbide is preceded by a structural transformation in the WC slip band. This transformation is consistent with the formation of an orthorhombic (pseudo-hexagonal) WC phase that may be derived from the original structure by the passage of one partial dislocation on every sucessive slip plane
Distributed actuator deformable mirror
Bonora, Stefano
2010-01-01
In this paper we present a Deformable Mirror (DM) based on the continuous voltage distribution over a resistive layer. This DM can correct the low order aberrations (defocus, astigmatism, coma and spherical aberration) using three electrodes with nine contacts leading to an ideal device for sensorless applications. We present a mathematical description of the mirror, a comparison between the simulations and the experimental results. In order to demonstrate the effectiveness of the device we compared its performance with the one of a multiactuator DM of similar properties in the correction of an aberration statistics. At the end of the paper an example of sensorless correction is shown.
Quantizing Earth surface deformations
Directory of Open Access Journals (Sweden)
C. O. Bowin
2015-03-01
Full Text Available The global analysis of Bowin (2010 used the global 14 absolute Euler pole set (62 Myr history from Gripp and Gordon (1990 and demonstrated that plate tectonics conserves angular momentum. We herein extend that analysis using the more detailed Bird (2003 52 present-day Euler pole set (relative to a fixed Pacific plate for the Earth's surface, after conversion to absolute Euler poles. Additionally, new analytical results now provide new details on upper mantle mass anomalies in the outer 200 km of the Earth, as well as an initial quantizing of surface deformations.
Nuclear fuel deformation phenomena
International Nuclear Information System (INIS)
Nuclear fuel encounters severe thermomechanical environments. Its mechanical response is profoundly influenced by an underlying heterogeneous microstructure but also inherently dependent on the temperature and stress level histories. The ability to adequately simulate the response of such microstructures, to elucidate the associated macroscopic response in such extreme environments is crucial for predicting both performance and transient fuel mechanical responses. This chapter discusses key physical phenomena and the status of current modelling techniques to evaluate and predict fuel deformations: creep, swelling, cracking and pellet-clad interaction. This chapter only deals with nuclear fuel; deformations of cladding materials are discussed elsewhere. An obvious need for a multi-physics and multi-scale approach to develop a fundamental understanding of properties of complex nuclear fuel materials is presented. The development of such advanced multi-scale mechanistic frameworks should include either an explicit (domain decomposition, homogenisation, etc.) or implicit (scaling laws, hand-shaking,...) linkage between the different time and length scales involved, in order to accurately predict the fuel thermomechanical response for a wide range of operating conditions and fuel types (including Gen-IV and TRU). (authors)
Plastic deformations in mine rock
Energy Technology Data Exchange (ETDEWEB)
Ryazantsev, N.A.; Nosach, A.K. (Donetskii Politekhnicheskii Institut (USSR))
1990-12-01
Presents results of investigations into plastic deformation of sandstone and coal samples. Tests were conducted on a triaxial compression testing machine with unequal components. Graphs of rock strength and deformation depending on lateral pressure are shown. It was found that rock strength and plasticity increase and decrease periodically as lateral pressure rises. The indicator of deformation localization is analyzed and calculation formulae are given. Experimental data testify to the fact that in the process of plastic deformation the deformation vector rotates by an angle of up to 60 degrees. On the basis of the uncovered effects of differential rotation and directional mass transfer that result from deformation localization the progress of a rock burst process is explained. The regularities found can explain many processes that occur in rock body, e.g. occurrence of disintegration zones around workings.
Effect of cold deformation on structure and properties of aluminium alloy 1441 sheets
International Nuclear Information System (INIS)
The influence of tensile deformation on the 1441 alloy (Al-Cu-Mg-Li-Zr) in four states: quenched; quenched, straightened and naturally aged; annealed; quenched, straightened and artificially aged one, has been studied. It has been ascertained that deformation after quenching results in a considerable growth of yield strength. Artificial aging makes an insignificant contribution to stregthening of deformed sheet. 2 refs.; 4 figs
Plastic Deformation of Metal Surfaces
DEFF Research Database (Denmark)
Hansen, Niels; Zhang, Xiaodan; Huang, Xiaoxu
2013-01-01
Plastic deformation of metal surfaces by sliding and abrasion between moving parts can be detrimental. However, when the plastic deformation is controlled for example by applying different peening techniques hard surfaces can be produced which can increase the fracture resistance and fatigue life...
Smooth deformations and cosmic statefinders
Capistrano, A J S
2014-01-01
We study the possibility that the universe is subjected to a deformation, besides its expansion described by Friedmann's equations. The concept of smooth deformation of a Riemannian manifolds associated with the extrinsic curvature is applied the standard FLRWcosmology. The resulting modified Friedman's equation whose solution is compared with the known phenomenological data.
Static multipole deformations in nuclei
International Nuclear Information System (INIS)
The physics of static multipole deformations in nuclei is reviewed. Nuclear static moments result from the delicate balance between the vibronic Jahn-Teller interaction (particle-vibration coupling) and the residual interaction (pairing force). Examples of various permanent nuclear deformations are discussed
Deformation Expression for Elements of Algebra
Omori, H.; Y. Maeda; Miyazaki, N.; Yoshioka, A.
2011-01-01
The purpose of this paper is to give a notion of deformation of expressions for elements of algebra. Deformation quantization (cf.[BF]) deforms the commutative world to a non-commutative world. However, this involves deformation of expression of elements of algebras even from a commutative world to another commutative world. This is indeed a deformation of expressions for elements of algebra.
Curved Space-Times from Strict Deformations?
Much, Albert
2016-01-01
We use a deformed differential structure and the Rieffel deformation to obtain a curved metric by deforming the flat space-time. In particular, a deformed Friedmann-Robertson-Walker and an ultra-static space-time emerge from this strict deformation scheme.
Deformation of Man Made Objects
Ibrahim, Mohamed
2012-07-01
We introduce a framework for 3D object deformation with primary focus on man-made objects. Our framework enables a user to deform a model while preserving its defining characteristics. Moreover, our framework enables a user to set constraints on a model to keep its most significant features intact after the deformation process. Our framework supports a semi-automatic constraint setting environment, where some constraints could be automatically set by the framework while others are left for the user to specify. Our framework has several advantages over some state of the art deformation techniques in that it enables a user to add new features to the deformed model while keeping its general look similar to the input model. In addition, our framework enables the rotation and extrusion of different parts of a model.
Zinoviev, Sergei
2014-05-01
Kuznetsk-Altai region is a part of the Central Asian Orogenic Belt. The nature and formation mechanisms of the observed structure of Kuznetsk-Altai region are interpreted by the author as the consequence of convergence of Tuva-Mongolian and Junggar lithospheric block structures and energy of collision interaction between the blocks of crust in Late-Paleozoic-Mesozoic period. Tectonic zoning of Kuznetsk-Altai region is based on the principle of adequate description of geological medium (without methods of 'primary' state recovery). The initial indication of this convergence is the crust thickening in the zone of collision. On the surface the mechanisms of lateral compression form a regional elevation; with this elevation growth the 'mountain roots' start growing. With an approach of blocks an interblock elevation is divided into various fragments, and these fragments interact in the manner of collision. The physical expression of collision mechanisms are periodic pulses of seismic activity. The main tectonic consequence of the block convergence and collision of interblock units is formation of an ensemble of regional structures of the deformation type on the basis of previous 'pre-collision' geological substratum [Chikov et al., 2012]. This ensemble includes: 1) allochthonous and autochthonous blocks of weakly deformed substratum; 2) folded (folded-thrust) systems; 3) dynamic metamorphism zones of regional shears and main faults. Characteristic of the main structures includes: the position of sedimentary, magmatic and PT-metamorphic rocks, the degree of rock dynamometamorphism and variety rock body deformation, as well as the styles and concentrations of mechanic deformations. 1) block terranes have weakly elongated or isometric shape in plane, and they are the systems of block structures of pre-collision substratum separated by the younger zones of interblock deformations. They stand out among the main deformation systems, and the smallest are included into the
DEFF Research Database (Denmark)
Lidang Jensen, M; Rix, M; Schrøder, Henrik Daa;
1995-01-01
Two premature siblings described herein had clinical features comparable to the fetal akinesia-hypokinesia deformation sequence (Pena-Shokeir syndrome) with polyhydramnios, intrauterine growth retardation, pulmonary hypoplasia, short umbilical cord and lethality. Autopsy revealed no thoracal or...
Changes of structure of austenitic steel caused by hot deformation
International Nuclear Information System (INIS)
The phenomena taking place during hot deformation and reconstruction of the microstructure of chromium-manganese and chromium-nickel austenitic steels of low SFE were analyzed. In particular, the problems of recovery of dynamic recrystallization as well as changes of the microstructure after deformation were analyzed. The research of hot deformation carried out by means of the torsion test on a torsional plastometer allowed to determine the impact of the deformation conditions (ε, ε', T) on austenitic steel workability and to capture basic differences in strengthening and softening of manganese in relation to the austenite more extensively tested austenite in Cr-Ni steel. The differences in deformation of both materials up to maximal yield stress εm result from various dislocation splitting and association ability during deformation process. Manganese austenite is generally susceptible to splitting of dislocation in initial phases of deformation - that is why the strengthening intensity is so high. Carbon is additional factor strongly strengthening solid solution. The process of dynamic recrystallization of Cr-Mn steel (SFE approx. 50 mJ/m2) deformed at 900oC takes place through dislocation climbing within boundaries of adjacent subgrains and their coalescence. Nucleation of new grains and growth in the process of dynamic recrystallization of Cr-Ni steel (SFE approx. 20 mJ/m2) takes place through migration of high-angle grain boundaries as well as through the mechanism of subgrain coalescence. In the whole range of the steady plastic flow of samples of both steel grades, the size of grain formed in the result of dynamic recrystallization practically does not depend on the ε deformation size, but only on deformation conditions (T, ε'). Regardless the initial grain size of the tested austenitic steel grades practically the same grain sizes were obtained during dynamic recrystallization at the temperature of 1000-1100oC. No considerable influence of other
International Nuclear Information System (INIS)
Some individuals within populations of Atlantic salmon Salmo salar and Arctic charr Salvelinus alpinus fed diets supplemented with oxytetracycline (OTC) developed spinal deformations. Possible differences in feed intake and growth of spinally deformed fish relative to fish without any deformities were investigated. Amongst Atlantic salmon, 17% of the fish fed OTC-supplemented feed developed spinal fractures, whereas none of the fish receiving the basic feed did so. Despite deformation of the spinal column, the injured fish continued to feed and grow, but at lower rates than unaffected individuals. In contrast to Atlantic salmon, Arctic charr showed no signs of spinal fractures at any time during the 65-day experiment
International Nuclear Information System (INIS)
Reaction and interaction cross sections of 17C on a carbon target have been re-analyzed using the modified Glauber model. The analysis with a deformed Woods-Saxon density/potential suggests a big deformation structure for 17C. The existence of a tail in the density distribution supports the possibility of it being a one-neutron halo structure. Under a deformed core plus a single-particle assumption, analysis shows a dominant d-wave of the valence neutron in 17C. (authors)
Impact between deformable bodies
International Nuclear Information System (INIS)
The bodies are represented by constant strain finite elements so that the element internal forces can most easily be calculated, especially after yielding has taken place when the stress and strain increments are related in accordance with the Prandtl-Reuss theory. In the case of axisymmetrical problems triangular axisymmetrical elements are used whose properties are approximately calculated by sampling at the centroid of the cross-section. The external applied forces arise from the impact and contact forces at the interfaces, and the inertia forces are obtained from lumped mass matrices. The equation of motion is solved by a central difference explicit scheme in small incremental time steps. This enables the stress propagation as well as the history of plastic deformation in the bodies to be traced throughout the duration of impact. The material law is idealised to be piecewise linear, with an initial elastic portion followed by one linear hardening segment. Perfect plasticity (zero hardening) can also be allowed. A simple procedure deals with the case of loading from an elastic initial state to a final plastic state in one time step. The program has been applied to the investigation of a number of axisymmetrical problems. The three dimensional version of the program is now being coded. Examples: impact of a falling fuel stringer in a storage tube; impact of a cylinder on a rigid boundary; supported circular plate loaded by uniformly distributed impulses; impact of a non-return valve in a pipe rupture; impact of a cylindrical fuel-waste flask; impact of a conical missile on a rigid surface. (orig./HP)
Nonlinear Deformable-body Dynamics
Luo, Albert C J
2010-01-01
"Nonlinear Deformable-body Dynamics" mainly consists in a mathematical treatise of approximate theories for thin deformable bodies, including cables, beams, rods, webs, membranes, plates, and shells. The intent of the book is to stimulate more research in the area of nonlinear deformable-body dynamics not only because of the unsolved theoretical puzzles it presents but also because of its wide spectrum of applications. For instance, the theories for soft webs and rod-reinforced soft structures can be applied to biomechanics for DNA and living tissues, and the nonlinear theory of deformable bodies, based on the Kirchhoff assumptions, is a special case discussed. This book can serve as a reference work for researchers and a textbook for senior and postgraduate students in physics, mathematics, engineering and biophysics. Dr. Albert C.J. Luo is a Professor of Mechanical Engineering at Southern Illinois University, Edwardsville, IL, USA. Professor Luo is an internationally recognized scientist in the field of non...
Carrier Deformability in Drug Delivery.
Morilla, Maria Jose; Romero, Eder Lilia
2016-01-01
Deformability is a key property of drug carriers used to increase the mass penetration across the skin without disrupting the lipid barrier. Highly deformable vesicles proved to be more effective than conventional liposomes in delivering drugs into and across the mammalian skin upon topical non occlusive application. In the past five years, highly deformable vesicles have been used for local delivery of drugs on joint diseases, skin cancer, atopic dermatitis, would healing, psoriasis, scar treatment, fungal, bacteria and protozoa infections. Promising topical vaccination strategies rely also in this type of carriers. Here we provide an overview on the main structural and mechanical features of deformable vesicles, to finish with an extensive update on their latest preclinical applications. PMID:26675226
Variable focal length deformable mirror
Headley, Daniel; Ramsey, Marc; Schwarz, Jens
2007-06-12
A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.
Nuclear deformation of lutetium isotopes
Ekström, C
1974-01-01
For odd-A lutetium isotopes the ground-state equilibrium deformations ( epsilon , epsilon /sub 4/) and the Nilsson model Z=71 single proton levels in an ( epsilon , epsilon /sub 4/)-representation are considered.
Soliton excitations in deformable solids
International Nuclear Information System (INIS)
Nonlinear effects caused by the interaction of quasiparticle (exciton, defecton etc.) with phonons in deformable solids are considered. In the one-dimensional case two types of solitary excitations are shown to appear situated at the bottom and the top of the quasiparticle energy band, respectively. The treatment is based on the general nonlinear dynamics theory of deformable crystals with quasiparticle excitations. (author). 10 refs
Quadratic deformation of Minkowski space
Cervantes, D.; Cervantes, R.; Lledó, M. A.; Nadal, F. A.
2012-09-01
We present a deformation of the Minkowski space as embedded into the conformal space (in the formalism of twistors) based in the quantum versions of the corresponding kinematic groups. We compute explicitly the star product, whose Poisson bracket is quadratic. We show that the star product although defined on the polynomials can be extended differentiably. Finally we compute the Eucliden and Minkowskian real forms of the deformation.
Measurement of deformations by NMR
Bytchenkoff, Dimitri; Rodts, Stéphane
2015-12-01
Two NMR data acquisition protocols together with corresponding data processing algorithms for locating macroscopic objects, measuring distances between them or monitoring their displacements or deformations with microscopic precision are presented and discussed. The performance of the methods is demonstrated by applying them to the measurement of deformations of a freely supported beam under loading. We believe that our methods will find their applications in mechanics, civil engineering and medicine.
Deformed Mittag-Leffler Polynomials
Miomir S. Stankovic; Marinkovic, Sladjana D.; Rajkovic, Predrag M.
2010-01-01
The starting point of this paper are the Mittag-Leffler polynomials introduced by H. Bateman [1]. Based on generalized integer powers of real numbers and deformed exponential function, we introduce deformed Mittag-Leffler polynomials defined by appropriate generating function. We investigate their recurrence relations, differential properties and orthogonality. Since they have all zeros on imaginary axes, we also consider real polynomials with real zeros associated to them.
Molecular deformation mechanisms in polyethylene.
Coutry, Sandry
2001-01-01
This work is concerned with details of the molecular changes caused by deformation and also establishes any conformational differences between linear and branched polyethylene before, during and after deformation. Four blends of isotopically labelled polymers of different types, rapidly quenched from the melt, have been studied by Mixed Crystal Infra-red Spectroscopy and Small Angle Neutron Scattering (SANS), in order to clarify any differences in the molecular basis of drawing...
Elevated temperature crack growth
Kim, K. S.; Vanstone, R. H.
1992-01-01
The purpose of this program was to extend the work performed in the base program (CR 182247) into the regime of time-dependent crack growth under isothermal and thermal mechanical fatigue (TMF) loading, where creep deformation also influences the crack growth behavior. The investigation was performed in a two-year, six-task, combined experimental and analytical program. The path-independent integrals for application to time-dependent crack growth were critically reviewed. The crack growth was simulated using a finite element method. The path-independent integrals were computed from the results of finite-element analyses. The ability of these integrals to correlate experimental crack growth data were evaluated under various loading and temperature conditions. The results indicate that some of these integrals are viable parameters for crack growth prediction at elevated temperatures.
Analysis of Mining Terrain Deformation Characteristics with Deformation Information System
Blachowski, Jan; Milczarek, Wojciech; Grzempowski, Piotr
2014-05-01
Mapping and prediction of mining related deformations of the earth surface is an important measure for minimising threat to surface infrastructure, human population, the environment and safety of the mining operation itself arising from underground extraction of useful minerals. The number of methods and techniques used for monitoring and analysis of mining terrain deformations is wide and increasing with the development of geographical information technologies. These include for example: terrestrial geodetic measurements, global positioning systems, remote sensing, spatial interpolation, finite element method modelling, GIS based modelling, geological modelling, empirical modelling using the Knothe theory, artificial neural networks, fuzzy logic calculations and other. The aim of this paper is to introduce the concept of an integrated Deformation Information System (DIS) developed in geographic information systems environment for analysis and modelling of various spatial data related to mining activity and demonstrate its applications for mapping and visualising, as well as identifying possible mining terrain deformation areas with various spatial modelling methods. The DIS concept is based on connected modules that include: the spatial database - the core of the system, the spatial data collection module formed by: terrestrial, satellite and remote sensing measurements of the ground changes, the spatial data mining module for data discovery and extraction, the geological modelling module, the spatial data modeling module with data processing algorithms for spatio-temporal analysis and mapping of mining deformations and their characteristics (e.g. deformation parameters: tilt, curvature and horizontal strain), the multivariate spatial data classification module and the visualization module allowing two-dimensional interactive and static mapping and three-dimensional visualizations of mining ground characteristics. The Systems's functionality has been presented on
q-Deformed Dynamics and Virial Theorem
Zhang, Jian-Zu
2002-01-01
In the framework of the q-deformed Heisenberg algebra the investigation of $q$-deformation of Virial theorem explores that q-deformed quantum mechanics possesses better dynamical property. It is clarified that in the case of the zero potential the theoretical framework for the q-deformed Virial theorem is self-consistent. In the selfadjoint states the q-deformed uncertainty relation essentially deviates from the Heisenberg one.
Plastic deformation of indium nanostructures
International Nuclear Information System (INIS)
Highlights: → Indium nanopillars display two different deformation mechanisms. → ∼80% exhibited low flow stresses near that of bulk indium. → Low strength nanopillars have strain rate sensitivity similar to bulk indium. → ∼20% of compressed indium nanopillars deformed at nearly theoretical strengths. → Low-strength samples do not exhibit strength size effects. - Abstract: Mechanical properties and morphology of cylindrical indium nanopillars, fabricated by electron beam lithography and electroplating, are characterized in uniaxial compression. Time-dependent deformation and influence of size on nanoscale indium mechanical properties were investigated. The results show two fundamentally different deformation mechanisms which govern plasticity in these indium nanostructures. We observed that the majority of indium nanopillars deform at engineering stresses near the bulk values (Type I), with a small fraction sustaining flow stresses approaching the theoretical limit for indium (Type II). The results also show the strain rate sensitivity and flow stresses in Type I indium nanopillars are similar to bulk indium with no apparent size effects.
Quadrupole Deformation of Barium Isotopes
Sugita, M; Furuno, K
1998-01-01
The B(E2:0_1^+ -> 2_1^+) values of the Ba isotopes (Z=56) exhibit a sharp increase in deformation as the neutron numbers approach the mid-shell value of N=66. This behavior is anomalous because the 2_1^+ level energies are very similar to those of the neighboring isotopes. By means of the axially-symmetric deformed Woods-Saxon (WS) hamiltonian plus the BCS method, we investigated the systematics of B(E2) of the Ba isotopes. We showed that 15% of the B(E2) values at N=66 was due to the level crossing, occurring at the deformation with beta being nearly 0.3, between the proton orbits originating from the orbits Omega=1/2^-(h11/2) and 9/2^+(g9/2) at zero deformation. The latter of these two was an intruder orbit originating from below the energy gap at Z=50, rising higher in energy with the deformation and intruding the Z=50-82 shell. These two orbits have the largest magnitude of the quadrupole moment with a different sign among the orbits near and below the Fermi surface. Occupancy and non-occupancy of these o...
Austenite decomposition in carbon steel under dynamic deformation conditions
Directory of Open Access Journals (Sweden)
A. Nowotnik
2007-01-01
Full Text Available Purpose: The main purpose of this paper was to estimate the effect of the dynamic conditions resulting fromdeformation process on the austenite decomposition into ferrite and pearlite (A→F+P in the commercial carbon steel.Design/methodology/approach: In the paper flow stress curves and microstructure of deformed steel within therange of discontinuous (austenite to pearlite and austenite to ferrite transformation at different strain rates andcooling rates were presented. The microstructure of hot deformed samples was tested by means of an opticaland electron microscopy.Findings: It was shown that the flow localization during hot deformation and preferred growth of the pearlitecolonies at shear bands was very limited. The most characteristic feature of the microstructure observed for hotdeformed samples was the development of carbides that nucleated along elongated ferrite grains.Research limitations/implications: In spite of intense strain hardening due to deformation and phasetransformation overlapping, microstructural observation of deformed samples did not reveal significant flowlocalization effects or heterogeneous distribution of the eutectoid components. Therefore, complementary testsshould be carried out on the steel with higher strain above the 0.5 value.Originality/value: There was no data referred to particular features of the dynamic processes, such as dynamicrecrystallization and recovery, dynamic precipitation, that can occur during austenite decomposition into ferrite,and especially during discontinuous transformation of austenite to pearlite.
Mixing of discontinuously deforming media
Smith, Lachlan D; Lester, Daniel R; Metcalfe, Guy
2016-01-01
Mixing of materials is fundamental to many natural phenomena and engineering applications. The presence of discontinuous deformations - such as shear banding or wall slip - creates new mechanisms for mixing and transport beyond those predicted by classical dynamical systems theory. Here we show how a novel mixing mechanism combining stretching with cutting and shuffling yields exponential mixing rates, quantified by a positive Lyapunov exponent, an impossibility for systems with cutting and shuffling alone or bounded systems with stretching alone, and demonstrate it in a fluid flow. While dynamical systems theory provides a framework for understanding mixing in smoothly deforming media, a theory of discontinuous mixing is yet to be fully developed. New methods are needed to systematize, explain and extrapolate measurements on systems with discontinuous deformations. Here we investigate 'webs' of Lagrangian discontinuities and show that they provide a template for the overall transport dynamics. Considering sl...
Phonon operators for deformed nuclei
International Nuclear Information System (INIS)
The mathematical formalism with the phonon operators independent of the signature of the angular momentum projection turns out to be inadequate for describing excited states of deformed nuclei. New phonon operators are introduced which depend on the signature of the angular momentum projection on the symmetry axis of a deformed nucleus. It is shown that the calculations with the new phonons take correctly into account the Pauli principle in two-phonon components of wave functions. The results obtained differ from those given by the phonons independent of the signature of the angular momentum projection. The new phonons must be used in deformed nuclei at taking systematically the Pauli principle into account and in calculations involving wave functions of excited states having components with more than one-phonon operator
Deformed Richardson-Gaudin model
International Nuclear Information System (INIS)
The Richardson-Gaudin model describes strong pairing correlations of fermions confined to a finite chain. The integrability of the Hamiltonian allows the algebraic construction of its eigenstates. In this work we show that the quantum group theory provides a possibility to deform the Hamiltonian preserving integrability. More precisely, we use the so-called Jordanian r-matrix to deform the Hamiltonian of the Richardson-Gaudin model. In order to preserve its integrability, we need to insert a special nilpotent term into the auxiliary L-operator which generates integrals of motion of the system. Moreover, the quantum inverse scattering method enables us to construct the exact eigenstates of the deformed Hamiltonian. These states have a highly complex entanglement structure which require further investigation.
Phonon operators in deformed nuclei
International Nuclear Information System (INIS)
For the description of the excited states in deformed nuclei new phonon operators are introduced, which depend on the sign of the angular momentum projection onto the symmetry axis of a deformed nucleus. In the calculations with new phonons the Pauli principle is correctly taken into account in the two-phonon components of the wave functions. There is a difference in comparison with the calculation with phonons independent of the sign of the angular momentum projection. The new phonons should be used in deformed nuclei if the Pauli principle is consistently taken into account and in the calculations with the excited state wave functions having the components with more than one phonon operator
Deforming baryons into confining strings
Hartnoll, S A; Hartnoll, Sean A.; Portugues, Ruben
2004-01-01
We find explicit probe D3-brane solutions in the infrared of the Maldacena-Nunez background. The solutions describe deformed baryon vertices: q external quarks are separated in spacetime from the remaining N-q. As the separation is taken to infinity we recover known solutions describing infinite confining strings in ${\\mathcal{N}}=1$ gauge theory. We present results for the mass of finite confining strings as a function of length. We also find probe D2-brane solutions in a confining type IIA geometry, the reduction of a G_2 holonomy M theory background. The interpretation of these solutions as deformed baryons/confining strings is not as straightforward.
Neutron scattering on deformed nuclei
International Nuclear Information System (INIS)
Measurements of neutron elastic and inelastic differential cross sections around 14 MeV for 9Be, C, 181Ta, 232Th, 238U and 239Pu have been analyzed using a coupled channel (CC) formalism for deformed nuclei and phenomenological global optical model potentials (OMP). For the actinide targets these results are compared with the predictions of a semi-microscopic calculation using Jeukenne, Lejeune and Mahaux (JLM) microscopic OMP and a deformed ground state nuclear density. The overall agreement between calculations and the measurements is reasonable good even for the very light nuclei, where the quality of the fits is better than those obtained with spherical OMP
Nanodisturbances in deformed Gum Metal
International Nuclear Information System (INIS)
Systematic experiments have been performed to characterize defect structures in deformed Gum Metal, a special titanium alloy with high strength, low Young's modulus, excellent cold workability and low resistance to shear in certain crystallographic planes. Results from high-resolution transmission electron microscopy characterization reveal nanodisturbances (planar nanoscopic areas of local shear) as typical elements of defect structures in deformed Gum Metal. A theoretical model is suggested describing nanodisturbances as nanoscale dipoles of non-conventional partial dislocations with arbitrary, non-quantized Burgers vectors. It is shown theoretically that the homogeneous generation of nanodisturbances is energetically favorable in Gum Metal, where they effectively carry plastic flow
Fourth order deformed general relativity
Cuttell, Peter D.; Sakellariadou, Mairi
2014-11-01
Whenever the condition of anomaly freedom is imposed within the framework of effective approaches to loop quantum cosmology, one seems to conclude that a deformation of general covariance is required. Here, starting from a general deformation we regain an effective gravitational Lagrangian including terms up to fourth order in extrinsic curvature. We subsequently constrain the form of the corrections for the homogeneous case, and then investigate the conditions for the occurrence of a big bounce and the realization of an inflationary era, in the presence of a perfect fluid or scalar field.
Numerical Modelling of Overburden Deformations
Directory of Open Access Journals (Sweden)
J. Barták
2002-01-01
Full Text Available This paper focuses on the application and verification of mathematical models of the effect of supporting measures on the reduction of overburden deformations. The study of the behaviour of the models is divided into three parts: reduction of the tunnelling effects on the Minorit monastery by means of a jet-grouting curtain; the behaviour of the Hvížďalka backfilled tunnel and a numerical analysis of the supporting measures affecting the tunnel deformations of the Mrázovka tunnel in Prague.
Computing layouts with deformable templates
Peng, Chihan
2014-07-27
In this paper, we tackle the problem of tiling a domain with a set of deformable templates. A valid solution to this problem completely covers the domain with templates such that the templates do not overlap. We generalize existing specialized solutions and formulate a general layout problem by modeling important constraints and admissible template deformations. Our main idea is to break the layout algorithm into two steps: a discrete step to lay out the approximate template positions and a continuous step to refine the template shapes. Our approach is suitable for a large class of applications, including floorplans, urban layouts, and arts and design. Copyright © ACM.
Analysis of internal crack healing mechanism under rolling deformation.
Gao, Haitao; Ai, Zhengrong; Yu, Hailiang; Wu, Hongyan; Liu, Xianghua
2014-01-01
A new experimental method, called the 'hole filling method', is proposed to simulate the healing of internal cracks in rolled workpieces. Based on the experimental results, the evolution in the microstructure, in terms of diffusion, nucleation and recrystallisation were used to analyze the crack healing mechanism. We also validated the phenomenon of segmented healing. Internal crack healing involves plastic deformation, heat transfer and an increase in the free energy introduced by the cracks. It is proposed that internal cracks heal better under high plastic deformation followed by slow cooling after rolling. Crack healing is controlled by diffusion of atoms from the matrix to the crack surface, and also by the nucleation and growth of ferrite grain on the crack surface. The diffusion mechanism is used to explain the source of material needed for crack healing. The recrystallisation mechanism is used to explain grain nucleation and growth, accompanied by atomic migration to the crack surface. PMID:25003518
Cavitation and grain growth during superplastic forming
Directory of Open Access Journals (Sweden)
M.J. Tan
2007-09-01
Full Text Available Purpose: The purpose of the paper is to study the cavitation and grain growth during superplastic forming.Design/methodology/approach: Superplastic alloys exhibit the extremely large elongation to failure by their high strain rate sensitivity. Cavities have widely been observed during superplastic deformation of metals and alloys and lead to the degradation of material properties such as tensile, creep, fatigue and stress-corrosion behavior. In this work, a finite element method is developed, which considers the grain growth and the effect of material damage.Findings: The effects of material parameters and deformation damage on the superplastic deformation process are numerically analyzed, and the means to control cavitation growth is discussed. The microstructural mechanism of grain growth during superplastic deformation is also studied. A new model considering the grain growth is proposed and applied to conventional superplastic materials The relationships between the strain, the strain rate, the test temperature, the initial grain size and the grain growth respectively in superplastic materials are discussed.Practical implications: The effect of variation of strain rate sensitivity (m value on the strain limit of the superplastic deformation is investigated, and the theoretically calculated values are compared with the experimental results.Originality/value: A new microstructure model based on the microstructural mechanism of superplastic deformation has been proposed. This model has been successfully applied to analyze conventional superplastic materials.
Deformable Models for Eye Tracking
DEFF Research Database (Denmark)
Vester-Christensen, Martin; Leimberg, Denis; Ersbøll, Bjarne Kjær;
2005-01-01
A deformable template method for eye tracking on full face images is presented. The strengths of the method are that it is fast and retains accuracy independently of the resolution. We compare the me\\$\\backslash\\$-thod with a state of the art active contour approach, showing that the heuristic...
Institute of Scientific and Technical Information of China (English)
LUO Jiao; LI MiaoQuan; LI XiaoLi
2008-01-01
There exists an interaction between microstructural evolution and deformation behavior in high temperature deformation of titanium alloys. And the microstruc-ture of titanium alloys is very sensitive to the process parameters of plastic de-formation process. In this paper, on the basis of plastic deformation mechanism of metals and alloys, a microstructural model including dislocation density rate equa-tion and grain growth rate equation is established with the dislocation density rate being an internal state variable. Applying the model to the high temperature de-formation process of Ti60 titanium alloy, the average relative errors of grain sizes between the experiments and the predictions are 9.47% for sampled data, and 13.01% for non-sampled data.
DEFF Research Database (Denmark)
Jónsdóttir, Kristjana Ýr; Jensen, Eva B. Vedel
The growth of planar and spatial objects is often modelled using one-dimensional size parameters, e.g. volume, area or average radius. We take a more detailed approach and model how the boundary of a growing object expands in time. We mainly consider star-shaped planar objects. The model can be...... regarded as a dynamic deformable template model. The limiting shape of the object may be circular but this is only one possibility among a range of limiting shapes. An application to tumour growth is presented. Two extensions of the model, involving time series and Lévy bases, respectively, are briefly...
Investigation of recrystallization texture evolution during annealing of hot deformed AA3104 alloy
Energy Technology Data Exchange (ETDEWEB)
Savoie, J.; Yiu, H.L. [Alcan International Ltd., Banbury (United Kingdom); Lauridsen, E.M.; Margulies, L.; Nielsen, S.F.; Schmidt, S. [Riso National Lab., Roskilde (Denmark); Ashton, M. [Manchester Materials Science Centre, Manchester (United Kingdom); Sebald, R. [Inst. fuer Metallkunde und Metallphysik, RWTH Aachen (Germany)
2002-07-01
Specimens, taken from hot rolled AA3104 slab, were deformed under plane strain compression conditions. The resulting crystallographic textures, obtained from standard X-ray and EBSD texture measurements, are strongly dependent on the deformation temperatures and strain rates. Two extreme conditions were considered, high Z (low temperature and high strain rate) and low Z (high temperature and low strain rate), which influence the cube texture development during both deformation and annealing. In addition, 3D X-ray diffraction microscopy (3DXRD) was utilised to characterise the growth of individual grains within the bulk of the samples deformed at high Z. Nucleation times and growth kinetics were measured in-situ and distributions of these from a population of grains were analysed according to their resulting orientations. (orig.)
2-D geometrical analysis of deformation
International Nuclear Information System (INIS)
Engineering structures such as dams, bridges, high rise buildings, etc. are subject to deformation. Deformation survey is therefore necessary to determine the magnitude and direction of such movements for the purpose of safety assessment. In this study, a strategy for two-step analyses for deformation survey rising the two dimensional (2-D) geodetic method has been developed, consisting of independent least squares estimation (LSE) of each epoch followed by deformation detection. Important aspects on LSE include global and local testing. In deformation detection, the following aspects were implemented; datum definition by the user. determination of stable datum points, geometrical analysis of deformation and graphic presentation. The developed strategy has been implemented in three computer programs, COMPUT, DEFORM and STRANS. Tests carried out with simulated and known data show that the developed strategy and programs are applicable for 2-D geometrical detection of deformation. (Author)
Deformed special relativity and deformed symmetries in a canonical framework
International Nuclear Information System (INIS)
In this paper we have studied the nature of kinematical and dynamical laws in κ-Minkowski spacetime from a new perspective: the canonical phase space approach. We discuss a particular form of κ-Minkowski phase space algebra that yields the κ-extended finite Lorentz transformations derived in [D. Kimberly, J. Magueijo, and J. Medeiros, Phys. Rev. D 70, 084007 (2004).]. This is a particular form of a deformed special relativity model that admits a modified energy-momentum dispersion law as well as noncommutative κ-Minkowski phase space. We show that this system can be completely mapped to a set of phase space variables that obey canonical (and not κ-Minkowski) phase space algebra and special relativity Lorentz transformation (and not κ-extended Lorentz transformation). The complete set of deformed symmetry generators are constructed that obeys an unmodified closed algebra but induce deformations in the symmetry transformations of the physical κ-Minkowski phase space variables. Furthermore, we demonstrate the usefulness and simplicity of this approach through a number of phenomenological applications both in classical and quantum mechanics. We also construct a Lagrangian for the κ-particle
Rheology of deformed Carrara marble: Insights from torsion experiments
Bruijn, R. H. C.; Delle Piane, C.; de Raadt, W. S.
2012-04-01
the developed texture. Subsequent deformation by torsion revealed the effect of initial texture on peak flow stress. Experimental conditions were designed to activate dislocation creep. Confining pressure was set at 300 MPa, temperature varied from 600 to 800 °C and the applied constant shear strain rate ranged from 3×10-4 to 1×10-3 s-1. Type I to III experiments revealed that reversed deformation recovers sheared grains, with the recovery of shape preferred orientation (SPO) requiring less strain than the recovery of crystallographic preferred orientation (CPO). They also showed that recrystallization is controlled by absolute strain rather than total strain. In terms of rheology, the first three types of experiments highlighted that strain reversal is easier than continued forward deformation (Bauschinger effect), provided sheared relict grains dominate in the fabric. Additionally, bulk sample flow behavior was shown to be dominated by the weakest segment in the composite sample. Type IV experiments quantified the weakening effect of texture at 33-67%, depending on temperature and the degree of initial CPO. All experiments showed that deformed rocks are weaker than their protolith equivalents. Therefore, despite possible alteration of shear direction, or prior grain growth, mylonites will localize strain during the next deformation event.
Quantum dynamics of deformed open systems
International Nuclear Information System (INIS)
A master equation for the deformed quantum harmonic oscillator interacting with a dissipative environment, in particular with a thermal bath, is derived in the microscopic model using perturbation theory . The coefficient of the master equation depend on the deformation function. The steady state solution of the equation for the density matrix in the number representation is obtained and the equilibrium energy of the deformed harmonic oscillator is calculated in the approximation of small deformation. (author)
Arithmetic Deformation Theory of Lie Algebras
Rastegar, Arash
2012-01-01
This paper is devoted to deformation theory of graded Lie algebras over $\\Z$ or $\\Z_l$ with finite dimensional graded pieces. Such deformation problems naturally appear in number theory. In the first part of the paper, we use Schlessinger criteria for functors on Artin local rings in order to obtain universal deformation rings for deformations of graded Lie algebras and their graded representations. In the second part, we use a version of Schlessinger criteria for functors on the Artinian cat...
Foot Deformities in Patients with Cerebral Palsy
E Ameri; A. Yeganeh
2007-01-01
Introduction & Objective: In patients with cerebral palsy (CP) the most common presentation is lower extremity deformity specially foot deformity. Inability to ambulation is the one of the most important disabilities, that dependent to the variety of factors such as severity of disease, kind of CP, etc. This study was aimed to assess prevalence of kinds of foot deformity in CP and communication between kind of CP and foot deformity and another hand inability to ambulation.Materials & Methods...
Deformable hybrid approach for haptic interaction
Susín Sánchez, Antonio; Mero, Máximo G.
2006-01-01
A new hybrid approach for deformable models is presented here and carried out in a virtual reality environment, achieving real time performance with haptic interactions. Our implementation consists in using two approaches for the deformable model. The deformation is modelled using simultaneously a Finite Element Method and a Mesh Free Method. With this Mesh Free method, particles are used to simulate large deformations in the volume region near the surface of the object. The remaining inte...
de Jonge, Tamás; Slullitel, Hernan; Dubousset, Jean; MILADI, Lotfi; Wicart, Philip; Illés, Tamás
2005-01-01
This is a retrospective study of 76 children who had had malignant tumours treated with laminectomy or laminoplasty and/or radiation therapy affecting the spine. Spinal tumours in children are extremely rare. However, their treatment can result in progressive spinal deformity. Radiation therapy affecting the growing spine can lead to asymmetric vertebral growth, causing kyphosis and/or scoliosis. These spinal deformities pose one of the most challenging problems for the spine surgeon. The aim...
Deformation and stress from in-pore drying-induced crystallisation of salt
Coussy, O.
2006-01-01
The deformation and the fracture of porous solids from internal crystallization of salt is explored in the framework of the thermodynamics of unsaturated brittle poroelasticity. In the first place the usual theory of crystal growth in confined conditions is further developed in order to include both the deformation and the drying of the porous solid. The thermodynamics reveals the existence of a dilation coefficient associated with the crystallization process, and provides a solute-crystal eq...
International Nuclear Information System (INIS)
The evolution of crystallographic texture in a nanocrystalline nickel–20 wt% cobalt alloy has been investigated for deformation up to large strains. The effect of texture on magnetic properties has been evaluated. The material shows characteristic copper-type texture at large strain levels. Microstructural examinations indicate that the evolution of texture is assisted by deformation-induced grain growth. The values of saturation magnetization and coercivity have been correlated with the crystallographic texture and grain size. - Highlights: • The deformation of a nanocrystalline nickel-20 wt% cobalt alloy, to large strains, leads to a characteristic copper-type rolling texture. • Dislocation based slip process is evident from the deformed microstructures at the later stages of deformation, while grain boundary assisted mechanisms are active during the initial stages. • The activity of dislocation at higher strain levels is facilitated by deformation-induced grain growth. • The evolution of magnetic properties is dependent on the deformation texture, while the effect of grain size is insignificant
Complete Positivity of Rieffel's Deformation Quantization
Kaschek, Daniel; Waldmann, Stefan
2008-01-01
In this paper we consider C*-algebraic deformations a la Rieffel and show that every state of the undeformed algebra can be deformed into a state of the deformed algebra in the sense of a continuous field of states. The construction is explicit and involves a convolution operator with a particular Gauss function.
Airborne Repeat Pass Interferometry for Deformation Measurements
Groot, J.; Otten, M.; Halsema, E. van
2000-01-01
In ground engineering the need for deformation measurements is urgent. SAR interferometry can be used to measure small (sub-wavelength) deformations. An experiment to investigate this for dike deformations was set up, using the C-band SAR system PHARUS (PHased ARray Universal SAR). This paper descri
Energy Technology Data Exchange (ETDEWEB)
Calais, D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1960-04-15
The various means by which plastic deformations by slip, twinning or kinking are produced by tension of imperfect {alpha} uranium single crystals prepared by a {beta} {yields} {alpha} phase change, have been studied by X-rays and micrographic examination. Depending on the crystallographic orientation with respect to the direction of the applied tension, and depending on the magnitude of the change in length, the crystals are deformed either preferentially according to a single mechanism, for example twinning, or simultaneously according to two or three mechanisms. The results of a subsequent annealing of the deformed single in the {alpha} phase are studied with respect to the deformation mechanisms. In the case of a deformation due primarily to (010) [100], (011) [100] or (110) [001] sliding, there occurs recrystallization by crystal growth selectivity. If the deformation occurs via deformation bands, there is recrystallization by 'oriented nucleation'. The crystals deformed preponderantly by twinning give on recrystallization perfect crystals having optimum dimensions and having orientational characteristics closely related to those of the original crystal. Finally are discussed some criteria relating to the geometry and the dynamics with a view to explaining the occurrence of such and such a deformation mechanism of a single crystal with a given orientation. This study, in conclusion, must help to define the best conditions (crystalline orientation and process of deformation) which will promote the growth of large, perfect, single crystals. (author) [French] Les divers modes de deformation plastique, glissement, maclage et pliage, que provoque la traction de monocristaux d'uranium {alpha} imparfaits prepares par changement de phase {beta} {yields} {alpha} ont ete etudies par rayons X et par examen micrographique. Suivant l'orientation cristallographique par rapport a la direction de l'axe de traction et suivant l'importance de l
Variational Approach and Deformed Derivatives
Weberszpil, José
2015-01-01
Recently, we have demonstrated that there exists a possible relationship between q-deformed algebras in two different contexts of Statistical Mechanics, namely, the Tsallis' framework and the Kaniadakis' scenario, with a local form of fractional-derivative operators for fractal media, the so-called Hausdorff derivatives, mapped into a continuous medium with a fractal measure. Here, in this paper, we present an extension of the traditional calculus of variations for systems containing deformed-derivatives embedded into the Lagrangian and the Lagrangian densities for classical and field systems. The results extend the classical Euler-Lagrange equations and the Hamiltonian formalism. The resulting dynamical equations seem to be compatible with those found in the literature, specially with mass-dependent and with nonlinear equations for systems in classical and quantum mechanics. Examples are presented to illustrate applications of the formulation. Also, the conserved Nether current, are worked out.
Relativistic description of deformed nuclei
International Nuclear Information System (INIS)
The author has shown that relativistic Hartree calculations using parameters that have been fit to the properties of nuclear matter can provide a good description of both spherical and axially deformed nuclei. The quantitative agreement with experiment is equivalent to that which was obtained in non-relativistic calculations using Skyrme interactions. The equilibrium deformation is strongly correlated with the size of the spin-orbit splitting, and that parameter sets which give roughly the correct value for this splitting provide the best agreement with the quadrupole moments in the s-d shell. Finally, for closed shell +/- 1 nuclei, it was shown that the self-consistent calculations are able to reproduce the experimental magnetic moments. This was not possible in relativistic calculations which include only the effects of the valence orbital
Performance through Deformation and Instability
Bertoldi, Katia
2015-03-01
Materials capable of undergoing large deformations like elastomers and gels are ubiquitous in daily life and nature. An exciting field of engineering is emerging that uses these compliant materials to design active devices, such as actuators, adaptive optical systems and self-regulating fluidics. Compliant structures may significantly change their architecture in response to diverse stimuli. When excessive deformation is applied, they may eventually become unstable. Traditionally, mechanical instabilities have been viewed as an inconvenience, with research focusing on how to avoid them. Here, I will demonstrate that these instabilities can be exploited to design materials with novel, switchable functionalities. The abrupt changes introduced into the architecture of soft materials by instabilities will be used to change their shape in a sudden, but controlled manner. Possible and exciting applications include materials with unusual properties such negative Poisson's ratio, phononic crystals with tunable low-frequency acoustic band gaps and reversible encapsulation systems.
Molecular deformation mechanisms in polyethylene
Coutry, S
2001-01-01
adjacent labelled stems is significantly larger when the DPE guest is a copolymer molecule. Our comparative studies on various types of polyethylene lead to the conclusion that their deformation behaviour under drawing has the same basis, with additional effects imputed to the presence of tie-molecules and branches. Three major points were identified in this thesis. The changes produced by drawing imply (1) the crystallisation of some of the amorphous polymer and the subsequent orientation of the newly formed crystals, (2) the re-orientation of the crystalline ribbons and (3) the beginning of crystallite break-up. However, additional effects were observed for the high molecular weight linear sample and the copolymer sample and were attributed, respectively, to the presence of tie-molecules and of branches. It was concluded that both the tie-molecules and the branches are restricting the molecular movement during deformation, and that the branches may be acting as 'anchors'. This work is concerned with details...
Variational approach and deformed derivatives
Weberszpil, J.; Helayël-Neto, J. A.
2016-05-01
Recently, we have demonstrated that there exists a possible relationship between q-deformed algebras in two different contexts of Statistical Mechanics, namely, the Tsallis' framework and the Kaniadakis' scenario, with a local form of fractional-derivative operators for fractal media, the so-called Hausdorff derivatives, mapped into a continuous medium with a fractal measure. Here, in this paper, we present an extension of the traditional calculus of variations for systems containing deformed-derivatives embedded into the Lagrangian and the Lagrangian densities for classical and field systems. The results extend the classical Euler-Lagrange equations and the Hamiltonian formalism. The resulting dynamical equations seem to be compatible with those found in the literature, specially with mass-dependent and with nonlinear equations for systems in classical and quantum mechanics. Examples are presented to illustrate applications of the formulation. Also, the conserved Noether current is worked out.
Making Deformable Template Models Operational
DEFF Research Database (Denmark)
Fisker, Rune
2000-01-01
Deformable template models are a very popular and powerful tool within the field of image processing and computer vision. This thesis treats this type of models extensively with special focus on handling their common difficulties, i.e. model parameter selection, initialization and optimization. A...... estimation of the model parameters, which applies a combination of a maximum likelihood and minimum distance criterion. Another contribution is a very fast search based initialization algorithm using a filter interpretation of the likelihood model. These two methods can be applied to most deformable template...... models making a non-expert user able to use the model. A comparative study of a number of optimization algorithms is also reported. In addition a general polygon-based model, an ellipse model and a textile model are proposed and a number of applications have been solved. Finally the Grenander model and...
q-Deformed Schroedinger equation
International Nuclear Information System (INIS)
In a q-deformed quantum mechanics the commutation relations between the generators of the SUq(2) algebra, L-vector and the position vector, r, are well defined and it is natural to take this vectors as the basic quantities from which all the others must be built. To build a q-deformed Schroedinger Hamiltonian a realization of p-vector entering the kinetic energy term was necessary to find. p-Vector can be written as a sum of two terms which are parallel and perpendicular to r-vector, respectively. We first obtained the general commutation relations involving the q-angular momentum and some quantities having definite transformation properties with respect to SUq(2) algebra. We then give a realization of the position vector and of the q-angular momentum, L, in terms of polar coordinates. Then, we obtained the realization of the linear momentum p made of a part perpendicular to r-vector, satisfying similar commutation relations to those corresponding to r-vector, and of a part parallel to r-vector supposed to have the simplest form, i.e., that coming from the ordinary partial derivative with respect to r-vector. We calculated the Eigenfunctions of the q-angular momentum, written like a series expansion in terms of cosθ. The result is a generalization of two hypergeometric functions which can be related to the q-deformed spherical functions Ylm. Some properties and relations satisfied by the Eigenfunctions are also listed. In the last section the q-deformed Schroedinger equation with scalar potential is given. Its solutions for Coulomb and three dimensional oscillator potential are briefly discussed
Deformation Quantization: Twenty Years After
Sternheimer, Daniel
1998-01-01
We first review the historical developments, both in physics and in mathematics, that preceded (and in some sense provided the background of) deformation quantization. Then we describe the birth of the latter theory and its evolution in the past twenty years, insisting on the main conceptual developments and keeping here as much as possible on the physical side. For the physical part the accent is put on its relations to, and relevance for, "conventional" physics. For the mathematical part we...
Deformation Micromechanics of Graphene Nanocomposites
Gong, Lei
2013-01-01
Graphene nanocomposites have been successfully prepared in this study in the form of a sandwich structure of PMMA/graphene/SU-8. It has been proved that Raman spectroscopy is a powerful technique in the characterisation of the structure and deformation of graphene. The 2D band of the monolayer graphene has been used in the investigation of stress transfer in the graphene reinforced nanocomposites. It has been demonstrated that the 2D band moves towards low frequency linearly under tensile str...
Constructal Hypothesis for Mechanical Deformation
Directory of Open Access Journals (Sweden)
Atanu Chatterjee
2012-08-01
Full Text Available Mild Steel specimen, when subjected to tensile forces shows considerable plastic deformation before fracture. A cross-section of the fractured specimen has the familiar cup – cone form and shows traces of a three – dimensional parabolic geometry. The morphing of the steel specimen from a volume to a point as a spontaneous, entropy producing or energy dispersing process is analysed using the Constructal law.
Visual simulation of deformable models
Hauth, Michael
2004-01-01
Computer animations are an essential part of today's visual production pipeline, for feature animated films and video games. By moving from static to dynamic scenes, immersion in virtual environments is greatly enhanced. Most of these animations however are concerning rigid or articulated bodies, and are generated manually by an artist or off-line. The interactive animation of deformable objects still is a challenging task, requiring high computational resources. Moreover, interactive enviro...
Large Scale Nanolaminate Deformable Mirror
Energy Technology Data Exchange (ETDEWEB)
Papavasiliou, A; Olivier, S; Barbee, T; Miles, R; Chang, K
2005-11-30
This work concerns the development of a technology that uses Nanolaminate foils to form light-weight, deformable mirrors that are scalable over a wide range of mirror sizes. While MEMS-based deformable mirrors and spatial light modulators have considerably reduced the cost and increased the capabilities of adaptive optic systems, there has not been a way to utilize the advantages of lithography and batch-fabrication to produce large-scale deformable mirrors. This technology is made scalable by using fabrication techniques and lithography that are not limited to the sizes of conventional MEMS devices. Like many MEMS devices, these mirrors use parallel plate electrostatic actuators. This technology replicates that functionality by suspending a horizontal piece of nanolaminate foil over an electrode by electroplated nickel posts. This actuator is attached, with another post, to another nanolaminate foil that acts as the mirror surface. Most MEMS devices are produced with integrated circuit lithography techniques that are capable of very small line widths, but are not scalable to large sizes. This technology is very tolerant of lithography errors and can use coarser, printed circuit board lithography techniques that can be scaled to very large sizes. These mirrors use small, lithographically defined actuators and thin nanolaminate foils allowing them to produce deformations over a large area while minimizing weight. This paper will describe a staged program to develop this technology. First-principles models were developed to determine design parameters. Three stages of fabrication will be described starting with a 3 x 3 device using conventional metal foils and epoxy to a 10-across all-metal device with nanolaminate mirror surfaces.
Capillary deformations of bendable films
Schroll, R. D.; Adda-Bedia, M.; Cerda, E.; Huang, J.; Menon, N.; Russell, T. P.; Toga, K. B.; Vella, D.; Davidovitch, B
2013-01-01
We address the partial wetting of liquid drops on ultrathin solid sheets resting on a deformable foundation. Considering the membrane limit of sheets that can relax compression through wrinkling at negligible energetic cost, we revisit the classical theory for the contact of liquid drops on solids. Our calculations and experiments show that the liquid-solid-vapor contact angle is modified from the Young angle, even though the elastic bulk modulus (E) of the sheet is so large that the ratio be...
Deterritorializing Drawing - transformation/deformation
DEFF Research Database (Denmark)
Brabrand, Helle
2012-01-01
but also from within by sensations, body ‘images’ are different to all other images. Twisting these body images make a mode of operation of art. The paper will address the above issues discussing modes of operation and appearance of my actual project. Acting in the reality of drawing, the project...... confront the body, situated in real time and depth, with drawing transforming and deforming time and depth....
Deformation inhomogeneity in large-grained AA5754 sheets
International Nuclear Information System (INIS)
Research highlights: → Microstructure and strain relationship at individual grain level was studied. → 'Hot spots' nucleate early and most keep growing throughout deformation stages. → 'Hot spots' are correlated with 'soft' grains and soft-evolution grains. → Grains with high Schmid factors tend to be 'soft' grains. → Grains with the direction close to tensile axis tend to become softer. - Abstract: Models for deformation and strain localization in polycrystals that incorporate microstructural features including particles are computationally intensive due to the large variation in scale in going from particles to grains to a specimen. As a result such models are generally 2-D in nature. This is an issue for experimental validation. We have therefore studied deformation heterogeneities and strain localization behavior of coarse-grained alloys with only two grains across the sample thickness, therefore mimicking 2-D behavior. Aluminum alloy sheets (AA5754) have been investigated by a number of surface techniques, including digital image correlation, slip trace analysis and electron backscattered diffraction, at the individual grain level. Local strain concentration zones appear from the very beginning of deformation, which then maintain sustained growth and lead, in one of these regions, to localization and final fracture. These 'hot spots' occur in areas with locally soft grains (i.e. grains with or close to the tensile direction) and soft-evolution orientations (i.e. grains with close to the tensile direction). These grains can be correlated with Taylor and/or Schmid factors.
Shape memory composite deformable mirrors
Riva, M.; Bettini, P.; Di Landro, L.; Sala, G.
2009-03-01
This paper deals with some of the critical aspects regarding Shape Memory Composite (SMC) design: firstly some technological aspects concerning embedding technique and their efficiency secondarily the lack of useful numerical tools for this peculiar design. It has been taken into account as a possible application a deformable panel which is devoted to act as a substrate for a deformable mirror. The activity has been mainly focused to the study of embedding technologies, activation and authority. In detail it will be presented the "how to" manufacturing of some smart panels with embedded NiTiNol wires in order to show the technology developed for SMC structures. The first part of the work compares non conventional pull-out tests on wires embedded in composites laminates (real condition of application), with standard pull-out in pure epoxy resin blocks. Considering the numerical approach some different modeling techniques to be implemented in commercial codes (ABAQUS) have been investigated. The Turner's thermo-mechanical model has been adopted for the modeling of the benchmark: A spherical panel devoted to work as an active substrate for a Carbon Fiber Reinforced Plastic (CFRP) deformable mirror has been considered as a significant technological demonstrator and possible future application (f=240mm, r.o.c.=1996mm).
Faraday instability in deformable domains
International Nuclear Information System (INIS)
Hydrodynamical instabilities are usually studied either in bounded regions or free to grow in space. In this article we review the experimental results of an intermediate situation, in which an instability develops in deformable domains. The Faraday instability, which consists in the formation of surface waves on a liquid experiencing a vertical forcing, is triggered in floating liquid lenses playing the role of deformable domains. Faraday waves deform the lenses from the initial circular shape and the mutual adaptation of instability patterns with the lens boundary is observed. Two archetypes of behaviour have been found. In the first archetype a stable elongated shape is reached, the wave vector being parallel to the direction of elongation. In the second archetype the waves exceed the response of the lens border and no equilibrium shape is reached. The lens stretches and eventually breaks into fragments that have a complex dynamics. The difference between the two archetypes is explained by the competition between the radiation pressure the waves exert on the lens border and its response due to surface tension.
Shapeable sheet without plastic deformation
Oppenheimer, Naomi; Witten, Thomas A.
2015-11-01
Randomly crumpled sheets have shape memory. In order to understand the basis of this form of memory, we simulate triangular lattices of springs whose lengths are altered to create a topography with multiple potential energy minima. We then deform these lattices into different shapes and investigate their ability to retain the imposed shape when the energy is relaxed. The lattices are able to retain a range of curvatures. Under moderate forcing from a state of local equilibrium, the lattices deform by several percent but return to their retained shape when the forces are removed. By increasing the forcing until an irreversible motion occurs, we find that the transitions between remembered shapes show cooperativity among several springs. For fixed lattice structures, the shape memory tends to decrease as the lattice is enlarged; we propose ways to counter this decrease by modifying the lattice geometry. We survey the energy landscape by displacing individual nodes. An extensive fraction of these nodes proves to be bistable; they retain their displaced position when the energy is relaxed. Bending the lattice to a stable curved state alters the pattern of bistable nodes. We discuss this shapeability in the context of other forms of material memory and contrast it with the shapeability of plastic deformation. We outline the prospects for making real materials based on these principles.
Deformation effects during hydride transformations in the Ta-H system
International Nuclear Information System (INIS)
A behavior of alloys with hydrogen constant content under thermocycling in stress fields and deformation effects in thermodynamically closed system of Ta-H are considered. Effect of hydrogenized tantalum heating and cooling on differential electroresistance, shear modulus and internal friction have been investigated. Spontaneuous deformation (twist effect) has been established under heating of hydrogenized and homogenized tantalum after prethermocycling of unloaded samples at hydroidation transition temperature. Cooling from homogeneous area under a load less than yield-point is accompanied by significant deformation at the temperature of hydridation.Investigated results enable one to conclude that observed deformation comprises a transition plasticity effect. Sample heating under no-load conditions leads to recovery of deformation accumulated during cooling. Besides it has been revealed that deformation of oriented transformation (DOT) exibits in Ta-H system. By this means the shape memory effect obtained as well as DOT demonstrated experimentally for the first time. Observed deformation effects are considered as a result of oriented growth or disapear of hydride crystals according to the deformation sheme
Cytocompatibility evaluation and surface characterization of TiNi deformed by high-pressure torsion
International Nuclear Information System (INIS)
Effect of high-pressure torsion (HPT) deformation on biocompatibility and surface chemistry of TiNi was systematically investigated. Ti–50 mol% Ni was subjected to HPT straining for different numbers of turns, N = 0.25, 0.5, 1, 5 and 10 at a rotation speed of 1 rpm. X-ray photoelectron spectroscopy observations after 7 days of cell culture revealed the changes in the surface oxide composition, enrichment of Ti and detection of nitrogen derived from organic molecules in the culture medium. Plating efficiency of L929 cells was slightly increased by HPT deformation though no significant difference was observed. Albumin adsorption was higher in HPT-deformed samples, while vitronectin adsorption was peaked at N = 1. HPT deformation was also found to effectively suppress the Ni ion release from the TiNi samples into the cell culture medium even after the low degree of deformation at N = 0.25. - Highlights: • Nanostructured Ti–50 mol%Ni alloy was produced using high-pressure torsion. • HPT deformation improved L929 growth on TiNi samples. • Changes in surface chemistry were observed in HPT deformed samples. • Protein adsorption behavior was influenced by the surface chemistry. • Ni ion release was suppressed in HPT deformed samples
... page: Was this page helpful? Also known as: GH; Human Growth Hormone; HGH; Somatotropin; Growth Hormone Stimulation Test; Growth Hormone ... I should know? How is it used? Growth hormone (GH) testing is primarily used to identify growth hormone ...
Quantification and validation of soft tissue deformation
DEFF Research Database (Denmark)
Mosbech, Thomas Hammershaimb; Ersbøll, Bjarne Kjær; Christensen, Lars Bager
2009-01-01
We present a model for soft tissue deformation derived empirically from 10 pig carcases. The carcasses are subjected to deformation from a known single source of pressure located at the skin surface, and the deformation is quantified by means of steel markers injected into the tissue. The steel...... markers are easy to distinguish from the surrounding soft tissue in 3D computed tomography images. By tracking corresponding markers using methods from point-based registration, we are able to accurately quantify the magnitude and propagation of the induced deformation. The deformation is parameterised by...
Stochastic deformation of a thermodynamic symplectic structure
Kazinski, P. O.
2009-01-01
A stochastic deformation of a thermodynamic symplectic structure is studied. The stochastic deformation is analogous to the deformation of an algebra of observables such as deformation quantization, but for an imaginary deformation parameter (the Planck constant). Gauge symmetries of thermodynamics and corresponding stochastic mechanics, which describes fluctuations of a thermodynamic system, are revealed and gauge fields are introduced. A physical interpretation to the gauge transformations and gauge fields is given. An application of the formalism to a description of systems with distributed parameters in a local thermodynamic equilibrium is considered.
Mesh deformation based on artificial neural networks
Stadler, Domen; Kosel, Franc; Čelič, Damjan; Lipej, Andrej
2011-09-01
In the article a new mesh deformation algorithm based on artificial neural networks is introduced. This method is a point-to-point method, meaning that it does not use connectivity information for calculation of the mesh deformation. Two already known point-to-point methods, based on interpolation techniques, are also presented. In contrast to the two known interpolation methods, the new method does not require a summation over all boundary nodes for one displacement calculation. The consequence of this fact is a shorter computational time of mesh deformation, which is proven by different deformation tests. The quality of the deformed meshes with all three deformation methods was also compared. Finally, the generated and the deformed three-dimensional meshes were used in the computational fluid dynamics numerical analysis of a Francis water turbine. A comparison of the analysis results was made to prove the applicability of the new method in every day computation.
Deficit, Seigniorage and the Growth Laffer Curve in developing countries
Ehrhart, Hélène; Minea, Alexandru; Villieu, P.
2011-01-01
The endogenous growth literature has established the existence of an inverted-U curve between taxes and economic growth, namely a Growth Laffer Curve (GLC). We develop a growth model with public investment as the engine of perpetual growth, and look for the effect of deficit, tax and money financing on economic growth. We study in particular the way fiscal and monetary policies (through deficit and seigniorage respectively) deform the GLC. An empirical section based on a panel of developing c...
Does deformation saturate seismic anisotropy?
Tatham, D. J.; Lloyd, G. E.; Butler, R. W.; Casey, M.
2006-12-01
The progressive simple shear deformation that characterizes ductile fault zones in the crust involves both rotation and intensification of the strain ellipsoid. These mathematic predictions have been confirmed repeatedly by finite strain determinations in outcrop studies of natural shear zones and used to test geodynamic models of mountain belts. Seismic anisotropy (SA) methods offer the opportunity to pursue these approaches in situ. First however, we must calibrate the magnitude and orientation of the SA ellipsoid against naturally deformed tectonites of known strain state and microstructure. Here we present data from a field analogue of mafic ductile crust in an amphibolite-facies shear zone developed in a deformed mafic dyke embedded within the Lewisian Gneiss (Badcall, NW Scotland). Deflection of pre-existing linear and planar elements and attenuation of the dyke into the shear zone are used to determine the strain gradient. Specimens collected along this gradient were used to establish the geometric fabric intensity defined by different minerals (hornblende grain alignment and ellipticity of plagioclase clots). Finally, petrophysical properties were calculated for the specimens using the SEM-EBSD measured populations of lattice preferred orientations (LPO) for all mineral phases. It is the hornblende-plagioclase LPO, combined in their modal proportions and modulated by the individual mineral single crystal elastic properties, which define the SA profile across the shear zone. Hornblende develops a strong preferred dimensional orientation and hence LPO at shear strains of about 2, whereas the plagioclase LPO remains close to random regardless of bulk strain. The modelled SA of the samples is dominated therefore by the amphibole LPO. Although the values of bulk shear strain vary across the shear zone (0 at the margins to greater than 12 in the centre), the calculated intensity of SA saturates at a shear strain of about 2. These results, if typical of large
Surgery of chest wall deformities
Matos, AC; Bernardo, JE; Fernandes, LE; Antunes, MJ
1997-01-01
OBJECTIVE: To evaluate the medium-term results of 77 surgical corrections in patients with chest wall deformities, 53 (68.8%) with pectus excavatum and 24 with pectus carinatum, operated upon from 1985 to 1994. METHODS: The mean age of the patients was 14.7 years (4-39 years) and 77% were younger than 15 years of age. There were 59 male (76.7%) and 18 female patients. Only four had a family history of the malformation. Seven patients (9.1%) presented with asthma-like symptoms, and 13 (16....
Dislocation Dynamics During Plastic Deformation
Messerschmidt, Ulrich
2010-01-01
The book gives an overview of the dynamic behavior of dislocations and its relation to plastic deformation. It introduces the general properties of dislocations and treats the dislocation dynamics in some detail. Finally, examples are described of the processes in different classes of materials, i.e. semiconductors, ceramics, metals, intermetallic materials, and quasicrystals. The processes are illustrated by many electron micrographs of dislocations under stress and by video clips taken during in situ straining experiments in a high-voltage electron microscope showing moving dislocations. Thus, the users of the book also obtain an immediate impression and understanding of dislocation dynamics.
Deformation Surveying of Railway Track
Štrba, Peter
2014-01-01
The aim of this diploma thesis is to specify the displacement and deformations of the railway tracks axis on bridge structures in cities of Zábřeh na Moravě and Břeclav. The bridge structures covered have great dilatation distances, therefore it is necessary to monitor the movements of the railway tracks depending on climatic conditions. GPS methods have been used throughout the whole measurement and data processing. The result includes also a comparison of GPS and conventional methods. The r...
Morita Theory in Deformation Quantization
Waldmann, Stefan
2010-01-01
Various aspects of Morita theory of deformed algebras and in particular of star product algebras on general Poisson manifolds are discussed. We relate the three flavours ring-theoretic Morita equivalence, $^*$-Morita equivalence, and strong Morita equivalence and exemplify their properties for star product algebras. The complete classification of Morita equivalent star products on general Poisson manifolds is discussed as well as the complete classification of covariantly Morita equivalent star products on a symplectic manifold with respect to some Lie algebra action preserving a connection.
Deformable Mirrors Correct Optical Distortions
2010-01-01
By combining the high sensitivity of space telescopes with revolutionary imaging technologies consisting primarily of adaptive optics, the Terrestrial Planet Finder is slated to have imaging power 100 times greater than the Hubble Space Telescope. To this end, Boston Micromachines Corporation, of Cambridge, Massachusetts, received Small Business Innovation Research (SBIR) contracts from the Jet Propulsion Laboratory for space-based adaptive optical technology. The work resulted in a microelectromechanical systems (MEMS) deformable mirror (DM) called the Kilo-DM. The company now offers a full line of MEMS DMs, which are being used in observatories across the world, in laser communication, and microscopy.
Gradient Domain Mesh Deformation - A Survey
Institute of Scientific and Technical Information of China (English)
Wei-Wei Xu; Kun Zhou
2009-01-01
This survey reviews the recent development of gradient domain mesh deformation method. Different to other deformation methods, the gradient domain deformation method is a surface-based, variational optimization method. It directly encodes the geometric details in differential coordinates, which are also called Laplacian coordinates in literature. By preserving the Laplacian coordinates, the mesh details can be well preserved during deformation. Due to the locality of the Laplacian coordinates, the variational optimization problem can be casted into a sparse linear system. Fast sparse linear solver can be adopted to generate deformation result interactively, or even in real-time. The nonlinear nature of gradient domain mesh deformation leads to the development of two categories of deformation methods: linearization methods and nonlinear optimization methods. Basically, the linearization methods only need to solve the linear least-squares system once. They are fast, easy to understand and control, while the deformation result might be suboptimal. Nonlinear optimization methods can reach optimal solution of deformation energy function by iterative updating. Since the computation of nonlinear methods is expensive, reduced deformable models should be adopted to achieve interactive performance. The nonlinear optimization methods avoid the user burden to input transformation at deformation handles, and they can be extended to incorporate various nonlinear constraints, like volume constraint, skeleton constraint, and so on. We review representative methods and related approaches of each category comparatively and hope to help the user understand the motivation behind the algorithms. Finally, we discuss the relation between physical simulation and gradient domain mesh deformation to reveal why it can achieve physically plausible deformation result.
Optical Deformability of Fluid Interfaces
Delville, J P; Wunenburger, R; Brevik, I; Delville, Jean-Pierre; Casner, Alexis; Wunenburger, Regis; Brevik, Iver
2004-01-01
The formation, deformation, and break-up of liquid interfaces are ubiquitous phenomena in nature. In the present article we discuss the deformation of a liquid interface produced by optical radiation forces. Usually, the bending of such an interface by the radiation pressure of a c.w. laser beam is weak. However, the effect can be enhanced significantly if one works with a near-critical phase-separated liquid mixture, whereby the surface tension becomes weak. The bending may in this way become as large as several tenths of micrometers, even with the use of only moderate laser power. This near-criticality is a key element in our experimental investigations as reviewed in the article. The effect is achieved by working with a micellar phase of microemulsions, at room temperature. We give a brief survey of the theory of electromagnetic forces on continuous matter, and survey earlier experiments in this area, such as the Ashkin-Dziedzic optical radiation force experiment on a water/air surface (1973), the Zhang-Ch...
Deformable human body model development
Energy Technology Data Exchange (ETDEWEB)
Wray, W.O.; Aida, T.
1998-11-01
This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). A Deformable Human Body Model (DHBM) capable of simulating a wide variety of deformation interactions between man and his environment has been developed. The model was intended to have applications in automobile safety analysis, soldier survivability studies and assistive technology development for the disabled. To date, we have demonstrated the utility of the DHBM in automobile safety analysis and are currently engaged in discussions with the U.S. military involving two additional applications. More specifically, the DHBM has been incorporated into a Virtual Safety Lab (VSL) for automobile design under contract to General Motors Corporation. Furthermore, we have won $1.8M in funding from the U.S. Army Medical Research and Material Command for development of a noninvasive intracranial pressure measurement system. The proposed research makes use of the detailed head model that is a component of the DHBM; the project duration is three years. In addition, we have been contacted by the Air Force Armstrong Aerospace Medical Research Laboratory concerning possible use of the DHBM in analyzing the loads and injury potential to pilots upon ejection from military aircraft. Current discussions with Armstrong involve possible LANL participation in a comparison between DHBM and the Air Force Articulated Total Body (ATB) model that is the current military standard.
Physics of Deformed Special Relativity
Girelli, F; Girelli, Florian; Livine, Etera R.
2004-01-01
In many different ways, Deformed Special Relativity (DSR) has been argued to provide an effective limit of quantum gravity in almost-flat regime. Unfortunately DSR is up to now plagued by many conceptual problems (in particular how it describes macroscopic objects) which forbids a definitive physical interpretation and clear predictions. Here we propose a consistent framework to interpret DSR. We extend the principle of relativity: the same way that Special Relativity showed us that the definition of a reference frame requires to specify its speed, we show that DSR implies that we must also take into account its mass. We further advocate a 5-dimensional point of view on DSR physics and the extension of the kinematical symmetry from the Poincare group to the Poincare-de Sitter group (ISO(4,1)). This leads us to introduce the concept of a pentamomentum and to take into account the renormalization of the DSR deformation parameter kappa. This allows the resolution of the "soccer ball problem" (definition of many-...
Deformable Registration of Digital Images
Institute of Scientific and Technical Information of China (English)
管伟光; 解林; 等
1998-01-01
is paper proposes a novel elastic model and presents a deformable registration method based on the model.The method registers images without the need to extract reatures from the images,and therefore works directly on grey-level images.A new similarity metric is given on which the formation of external forces is based.The registration method,taking the coarse-to-fine strategy,constructs external forces in larger scales for the first few iterations to rely more on global evidence,and ther in smaller scales for later iterations to allow local refinements.The stiffness of the elastic body decreases as the process proceeds.To make it widely applicable,the method is not restricted to any type of transformation.The variations between images are thought as general free-form deformations.Because the elastic model designed is linearized,it can be solved very efficiently with high accuracy.The method has been successfully tested on MRI images.It will certainly find other uses such as matching time-varying sequences of pictures for motion analysis,fitting templates into images for non-rigid object recognition,matching stereo images for shape recovery,etc.
Deformable templates for circle recognition
International Nuclear Information System (INIS)
An algorithm for the circle recognition, using deformable templates, was carried out and its performance was studied. The displacement of the points from circles and the presence of noise that appear in real situations were taken into account. The deformable templates algorithm is initialized by Hough transform, which performs a rough evaluation of parameters. However due to inefficiency of the standard Hough transform, a new fast Hough transform procedure was proposed with an automatic choice of the appropriate cut on histograms and handling of splitting peaks. Having the approximate number of arms and the corresponding initial values of the parameters from the Hough transform as input, a neural network finds circles with high resolution. To avoid getting stuck into local minima we decrease the interaction between the arms and use the simulated annealing procedure where the system is allowed to thermalize for a sequence of temperature according to the Boltzmann distribution. Besides we penalize the case in which an elastic circle stopped its evolution having not enough points on it. Simulated data were used to study the efficiency of the algorithm depending on such factors as the noise level, displacements of the points from circles, the number of points per circle and the distance between the centre of two overlapped circles. Results show the satisfactory robustness of our algorithm to background contaminations. Then this technique was successfully applied to real data obtained in Au-Pb interactions from the RICH detectors used in CERES/NA45 experiment
PARASITES, DISEASES AND DEFORMITIES OF COBIA
Directory of Open Access Journals (Sweden)
Ewen McLean
2008-01-01
Full Text Available Cobia, Rachycentron canadum, is the only member of the family Rachycentridae (Order Perciformes and as a warm–water fish is to be found in tropical and subtropical waters. The species has been reported in eastern Mediterranean waters and it is likely that in this particular case, cobia are lessespian. Cobia has been farmed in Taiwan since the early 1990s and today nascent cobia aquaculture operations operate throughout South East and Eastern Asia, in Gulf of Mexico and Caribbean Sea as well as in the United States. Many other nations are presently considering adopting cobia as a new species for aquaculture. Production by aquaculture experienced a 7000–fold increase from 1995 to 2005. The increased interest in the species has evolved due in large part to its many excellent characteristics which include good growth, with production of 6 kg live weight fish being possible over a year–long production cycle. Cobia are accepting of pond, net pens and recirculation–based culture; their fillet quality is high and meat delectable; They readily take formulated feeds and respond well to alternate proteins in their diets. Like other species new to aquaculture however, enlarged farming activities have been accompanied by increased incidence of commonly–encountered and emerging diseases. As an aid to current and potential producers as well as researchers, the following provides an overview of the published literature on cobia diseases, parasites and physical deformities.
Uniaxial deformation of a soft porous material
MacMinn, Chris; Dufresne, Eric; Wettlaufer, John
2015-11-01
Compressing a porous material will decrease the volume of pore space, driving fluid out. Similarly, injecting fluid into a porous material will drive mechanical deformation, distorting the solid skeleton. This poromechanical coupling has applications ranging from cell and tissue mechanics to geomechanics and hydrogeology. The classical theory of linear poroelasticity captures this coupling by combining Darcy's law with linear elasticity and then further linearizing in the strain. This is a good model for very small deformations, but it becomes increasingly inappropriate as deformations grow larger, and moderate to large deformations are common in the context of phenomena such as swelling, damage, and extreme softness. Here, we compare the predictions of linear poroelasticity with those of a rigorous large-deformation framework in the context of two uniaxial model problems. We explore the error associated with the linear model in both steady and dynamic situations, as well as the impact of allowing the permeability to vary with the deformation.
Electric multipole plasmons in deformed sodium clusters
Kleinig, W; Reinhard, P G
2001-01-01
The random-phase-approximation (RPA) method with separable residual forces (SRPA) is proposed for the description of multipole electric oscillations of valence electrons in deformed alkali metal clusters. Both the deformed mean field and residual interaction are derived self-consistently from the Kohn-Sham functional. SRPA drastically simplifies the computational effort which is urgent if not decisive for deformed systems. The method is applied to the description of dipole, quadrupole and octupole plasmons in deformed sodium clusters of a moderate size. We demonstrate that, in clusters with the size N>50, Landau damping successfully competes with deformation splitting and even becomes decisive in forming the width and gross structure of the dipole plasmon. Besides, the plasmon is generated by excitations from both ground state and shape isomers. In such clusters familiar experimental estimates for deformation splitting of dipole plasmon are useless.
Exactly marginal deformations from exceptional generalised geometry
Ashmore, Anthony; Graña, Mariana; Petrini, Michela; Waldram, Daniel
2016-01-01
We apply exceptional generalised geometry to the study of exactly marginal deformations of $\\mathcal{N}=1$ SCFTs that are dual to generic AdS$_5$ flux backgrounds in type IIB or eleven-dimensional supergravity. In the gauge theory, marginal deformations are parametrised by the space of chiral primary operators of conformal dimension three, while exactly marginal deformations correspond to quotienting this space by the complexified global symmetry group. We show how the supergravity analysis gives a geometric interpretation of the gauge theory results. The marginal deformations arise from deformations of generalised structures that solve moment maps for the generalised diffeomorphism group and have the correct charge under the generalised Reeb vector, generating the R-symmetry. If this is the only symmetry of the background, all marginal deformations are exactly marginal. If the background possesses extra isometries, there are obstructions that come from fixed points of the moment maps. The exactly marginal de...
Deformation Models Tracking, Animation and Applications
Torres, Arnau; Gómez, Javier
2013-01-01
The computational modelling of deformations has been actively studied for the last thirty years. This is mainly due to its large range of applications that include computer animation, medical imaging, shape estimation, face deformation as well as other parts of the human body, and object tracking. In addition, these advances have been supported by the evolution of computer processing capabilities, enabling realism in a more sophisticated way. This book encompasses relevant works of expert researchers in the field of deformation models and their applications. The book is divided into two main parts. The first part presents recent object deformation techniques from the point of view of computer graphics and computer animation. The second part of this book presents six works that study deformations from a computer vision point of view with a common characteristic: deformations are applied in real world applications. The primary audience for this work are researchers from different multidisciplinary fields, s...
Stress-dependent finite growth in soft elastic tissues.
Rodriguez, E K; Hoger, A; McCulloch, A D
1994-04-01
Growth and remodeling in tissues may be modulated by mechanical factors such as stress. For example, in cardiac hypertrophy, alterations in wall stress arising from changes in mechanical loading lead to cardiac growth and remodeling. A general continuum formulation for finite volumetric growth in soft elastic tissues is therefore proposed. The shape change of an unloaded tissue during growth is described by a mapping analogous to the deformation gradient tensor. This mapping is decomposed into a transformation of the local zero-stress reference state and an accompanying elastic deformation that ensures the compatibility of the total growth deformation. Residual stress arises from this elastic deformation. Hence, a complete kinematic formulation for growth in general requires a knowledge of the constitutive law for stress in the tissue. Since growth may in turn be affected by stress in the tissue, a general form for the stress-dependent growth law is proposed as a relation between the symmetric growth-rate tensor and the stress tensor. With a thick-walled hollow cylinder of incompressible, isotropic hyperelastic material as an example, the mechanics of left ventricular hypertrophy are investigated. The results show that transmurally uniform pure circumferential growth, which may be similar to eccentric ventricular hypertrophy, changes the state of residual stress in the heart wall. A model of axially loaded bone is used to test a simple stress-dependent growth law in which growth rate depends on the difference between the stress due to loading and a predetermined growth equilibrium stress. PMID:8188726
Deformations of Quasicoherent Sheaves of Algebras
Lunts, Valery A.
2001-01-01
Gerstenhaber and Schack ([GS]) developed a deformation theory of presheaves of algebras on small categories. We translate their cohomological description to sheaf cohomology. More precisely, we describe the deformation space of (admissible) quasicoherent sheaves of algebras on a quasiprojective scheme $X$ in terms of sheaf cohomology on $X$ and $X\\times X$. These results are applied to the study of deformations of the sheaf $D_X$ of differential operators on $X$. In particular, in case $X$ is...
Self-adjointness of deformed unbounded operators
Energy Technology Data Exchange (ETDEWEB)
Much, Albert [Instituto de Ciencias Nucleares, UNAM, México D.F. 04510 (Mexico)
2015-09-15
We consider deformations of unbounded operators by using the novel construction tool of warped convolutions. By using the Kato-Rellich theorem, we show that unbounded self-adjoint deformed operators are self-adjoint if they satisfy a certain condition. This condition proves itself to be necessary for the oscillatory integral to be well-defined. Moreover, different proofs are given for self-adjointness of deformed unbounded operators in the context of quantum mechanics and quantum field theory.
Asymmetric deformation of contracting human gastrocnemius muscle
Kinugasa, Ryuta; Hodgson, John A.; Edgerton, V. Reggie; Sinha, Shantanu
2011-01-01
Muscle fiber deformation is related to its cellular structure, as well as its architectural arrangement within the musculoskeletal system. While playing an important role in aponeurosis displacement, and efficiency of force transmission to the tendon, such deformation also provides important clues about the underlying mechanical structure of the muscle. We hypothesized that muscle fiber cross section would deform asymmetrically to satisfy the observed constant volume of muscle during a contra...
Interactive Multigrid Refinement for Deformable Image Registration
Wu Zhou; Yaoqin Xie
2013-01-01
Deformable image registration is the spatial mapping of corresponding locations between images and can be used for important applications in radiotherapy. Although numerous methods have attempted to register deformable medical images automatically, such as salient-feature-based registration (SFBR), free-form deformation (FFD), and demons, no automatic method for registration is perfect, and no generic automatic algorithm has shown to work properly for clinical applications due to the fact tha...
Integrable Deformations of the XXZ Spin Chain
Beisert, Niklas; de Leeuw, Marius; Loebbert, Florian
2013-01-01
We consider integrable deformations of the XXZ spin chain for periodic and open boundary conditions. In particular, we classify all long-range deformations and study their impact on the spectrum. As compared to the XXX case, we have the z-spin at our disposal, which induces two additional deformations: the short-range magnetic twist and a new long-range momentum-dependent twist.
Microstructural development of high temperature deformed AZ31 magnesium alloys
International Nuclear Information System (INIS)
Due to their significant role in automobile industries, high temperature deformation of Mg–Al–Zn alloys (AZ31) at constant stress (i.e. creep) were studied at a wide range of stresses and temperatures to characterize underlying deformation mechanism, dynamic recrystallization (DRX) and dislocation density evolution. Various microstructures (e.g. grain growth & DRX) are noted during steady-state creep mechanisms such as grain boundary sliding (GBS), dislocation glide creep (DGC) and dislocation climb creep (DCC). Although a combination of DRX and grain growth is characteristic of low stacking fault energy materials like Mg alloys at elevated temperatures, observation reveals grain growth at low strain-rates (GBS region) along with dynamic recovery (DRV) mechanism. X-Ray Diffraction (XRD) analysis revealed a decrease in dislocation density during GBS region while it increased under dislocation based creep mechanisms which could be related to the possible DRV and DRX respectively. Scanning Electron Microscopic (SEM) characterization of the fracture surface reveals more inter-granular fracture for large grains (i.e. GBS region with DRV process) and more dimple shape fracture for small grains (i.e. DGC & DCC region with DRX)
Microstructural development of high temperature deformed AZ31 magnesium alloys
Energy Technology Data Exchange (ETDEWEB)
Shahbeigi Roodposhti, Peiman, E-mail: pshahbe@ncsu.edu; Sarkar, Apu; Murty, Korukonda Linga
2015-02-25
Due to their significant role in automobile industries, high temperature deformation of Mg–Al–Zn alloys (AZ31) at constant stress (i.e. creep) were studied at a wide range of stresses and temperatures to characterize underlying deformation mechanism, dynamic recrystallization (DRX) and dislocation density evolution. Various microstructures (e.g. grain growth & DRX) are noted during steady-state creep mechanisms such as grain boundary sliding (GBS), dislocation glide creep (DGC) and dislocation climb creep (DCC). Although a combination of DRX and grain growth is characteristic of low stacking fault energy materials like Mg alloys at elevated temperatures, observation reveals grain growth at low strain-rates (GBS region) along with dynamic recovery (DRV) mechanism. X-Ray Diffraction (XRD) analysis revealed a decrease in dislocation density during GBS region while it increased under dislocation based creep mechanisms which could be related to the possible DRV and DRX respectively. Scanning Electron Microscopic (SEM) characterization of the fracture surface reveals more inter-granular fracture for large grains (i.e. GBS region with DRV process) and more dimple shape fracture for small grains (i.e. DGC & DCC region with DRX)
Microstructure evolution model based on deformation mechanism of titanium alloy in hot forming
Institute of Scientific and Technical Information of China (English)
LI Xiao-li; LI Miao-quan
2005-01-01
The microstructure evolution in hot forming will affect the mechanical properties of the formed product.However, the microstructure is sensitive to the process variables in deformation process of metals and alloys. A microstructure evolution model of a titanium alloy in hot forming, which included dislocation density rate and primary α phase grain size, was presented according to the deformation mechanism and driving forces, in which the effect of the dislocation density rate on the grain growth was studied firstly. Applying the model to the high temperature deformation process of a TC6 alloy with deformation temperature of 1 133 - 1 223 K, strain rate of 0.01 -50 s-1 and height reduction of 30%, 40% and 50%, the material constants in the present model were calculated by the genetic algorithm(GA) based objective optimization techniques. The calculated results of a TC6 alloy are in good agreement with the experimental ones.
Energy Technology Data Exchange (ETDEWEB)
Nowotnik, Andrzej; Rokicki, Pawel; Mrowka-Nowotnik, Grazyna; Sieniawski, Jan [Rzeszow Univ. of Technology (Poland). Dept. of Material Science
2015-07-15
The authors performed uniaxial compression tests of nickel-based superalloys: single crystal CMSX-4, also precipitation hardened; Inconel 718 and X750, at temperatures below the γ' solvus, in order to study the effect of temperature and strain rate on their flow stress and microstructural development. On the basis of the obtained flow stress values, the activation energy of a high-temperature deformation process was estimated. Microstructural observations of the deformed samples at high temperatures, previously solution heat treated and aged CMSX-4 and Inconel alloys revealed non-uniform deformation effects. Distribution of either molybdenum- or niobium-rich carbides was found to be affected by localized flow within the investigated strain range at relatively low deformation temperatures, 720-850 C. Microstructural examination of the alloys also showed that shear banding and cavity growth were responsible for the decrease in flow stress and a specimen fracture at larger strains.
Deformation twinning: Influence of strain rate
Energy Technology Data Exchange (ETDEWEB)
Gray, G.T. III
1993-11-01
Twins in most crystal structures, including advanced materials such as intermetallics, form more readily as the temperature of deformation is decreased or the rate of deformation is increased. Both parameters lead to the suppression of thermally-activated dislocation processes which can result in stresses high enough to nucleate and grow deformation twins. Under high-strain rate or shock-loading/impact conditions deformation twinning is observed to be promoted even in high stacking fault energy FCC metals and alloys, composites, and ordered intermetallics which normally do not readily deform via twinning. Under such conditions and in particular under the extreme loading rates typical of shock wave deformation the competition between slip and deformation twinning can be examined in detail. In this paper, examples of deformation twinning in the intermetallics TiAl, Ti-48Al-lV and Ni{sub 3}A as well in the cermet Al-B{sub 4}C as a function of strain rate will be presented. Discussion includes: (1) the microstructural and experimental variables influencing twin formation in these systems and twinning topics related to high-strain-rate loading, (2) the high velocity of twin formation, and (3) the influence of deformation twinning on the constitutive response of advanced materials.
Foot Deformities in Patients with Cerebral Palsy
Directory of Open Access Journals (Sweden)
E. Ameri
2007-04-01
Full Text Available Introduction & Objective: In patients with cerebral palsy (CP the most common presentation is lower extremity deformity specially foot deformity. Inability to ambulation is the one of the most important disabilities, that dependent to the variety of factors such as severity of disease, kind of CP, etc. This study was aimed to assess prevalence of kinds of foot deformity in CP and communication between kind of CP and foot deformity and another hand inability to ambulation.Materials & Methods: 100 patients with cerebral palsy with age 3-20 y (average 12.9y were assessed in Shafa Yahyaian Orthopedic Center and kinds of CP & foot deformity was evaluated. In these patients, 84 subjects were selected with age 7-20 y and were evaluated for ability to walking.Results: The most common type of CP was spastic and the most common form of CP was (Quadri-Di-hemi-para plegic respectively. The most common form of foot deformity was equines. Inability to walking in patients with foot deformity was more than without it (P<0.03, and in quadriplegic CP more than another types and in hemiplegic less than others.Conclusion: The most common deformity in foot in patients with CP was equines and then equino varus & equines valgus respectively. Foot deformity is the one of the factors that effect on ability to ambulation in patients with CP. Inability to ambulation in quadriplegic CP is more than others and in hemiplegic CP less than other types of CP.
Metric Gauge Fields in Deformed Special Relativity
Cardone, F; Petrucci, A
2014-01-01
We show that, in the framework of Deformed Special Relativity (DSR), namely a (four-dimensional) generalization of the (local) space-time struc- ture based on an energy-dependent "deformation" of the usual Minkowski geometry, two kinds of gauge symmetries arise, whose spaces either coin- cide with the deformed Minkowski space or are just internal spaces to it. This is why we named them "metric gauge theories". In the case of the internal gauge ?elds, they are a consequence of the deformed Minkowski space (DMS) possessing the structure of a generalized Lagrange space. Such a geometrical structure allows one to de?ne curvature and torsion in the DMS.
Strong crystal size effect on deformation twinning
DEFF Research Database (Denmark)
Yu, Qian; Shan, Zhi-Wei; Li, Ju;
2010-01-01
find that the stress required for deformation twinning increases drastically with decreasing sample size of a titanium alloy single crystal7, 8, until the sample size is reduced to one micrometre, below which the deformation twinning is entirely replaced by less correlated, ordinary dislocation...... plasticity. Accompanying the transition in deformation mechanism, the maximum flow stress of the submicrometre-sized pillars was observed to saturate at a value close to titanium’s ideal strength9, 10. We develop a ‘stimulated slip’ model to explain the strong size dependence of deformation twinning. The...
Origami-enabled deformable silicon solar cells
Energy Technology Data Exchange (ETDEWEB)
Tang, Rui; Huang, Hai; Liang, Hanshuang; Liang, Mengbing [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Tu, Hongen; Xu, Yong [Electrical and Computer Engineering, Wayne State University, 5050 Anthony Wayne Dr., Detroit, Michigan 48202 (United States); Song, Zeming; Jiang, Hanqing, E-mail: hanqing.jiang@asu.edu [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States); Yu, Hongyu, E-mail: hongyu.yu@asu.edu [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); School of Earth and Space Exploration, Arizona State University, Tempe, Arizona 85287 (United States)
2014-02-24
Deformable electronics have found various applications and elastomeric materials have been widely used to reach flexibility and stretchability. In this Letter, we report an alternative approach to enable deformability through origami. In this approach, the deformability is achieved through folding and unfolding at the creases while the functional devices do not experience strain. We have demonstrated an example of origami-enabled silicon solar cells and showed that this solar cell can reach up to 644% areal compactness while maintaining reasonable good performance upon cyclic folding/unfolding. This approach opens an alternative direction of producing flexible, stretchable, and deformable electronics.
International Nuclear Information System (INIS)
Highlights: ► Microstructural evolution of extruded Al–Mg–Sc was divided into three stages. ► Subgrain rotation and coalescence occurred in early strain hardening stage. ► Dynamic recrystallization in the middle stage resulted in strain softening. ► Grain boundary sliding and dynamic grain growth occurred in final deformation stage. ► Friction stir processed alloy remained a random grain distribution at various strains. - Abstract: The microstructural evolution of unrecrystallized (extruded) and recrystallized (friction stir processed, FSP) Al–Mg–Sc alloys during superplastic straining was investigated using electron backscatter diffraction (EBSD). The unrecrystallized structure gradually transformed into a recrystallized structure, characterized by equiaxed grains, random boundary misorientation distribution and a weak texture at high strains. This evolution was divided into three stages based on true stress–strain curves and EBSD maps, i.e. subgrain rotation and coalescence in the early stage, dynamic recrystallization in the middle stage, and grain boundary sliding (GBS) and dynamic grain growth in the final stage. By comparison, the recrystallized grains in the FSP Al–Mg–Sc maintained a random distribution during the whole deformation process, however the grain size increased significantly with increasing strain, indicating that the main deformation mechanism was always GBS and dynamic grain growth. A deformation model was proposed to explain the microstructural evolution during superplastic deformation. The microstructure with the random boundary misorientations reaches a dynamic balance because the transformation between high-angle grain boundaries and low-angle grain boundaries is equivalent.
Wilson, P. I. R.; McCaffrey, K. J. W.; Jarvis, I.; Murphy, P.; Davidson, J. P.
2012-04-01
Most studies of sill and laccolith complexes have focused on the internal architecture and thermal effects of these intrusions, while few have looked in detail at host rock deformation structures associated with their emplacement. Various sill and laccolith emplacement mechanisms have been proposed (e.g. radial growth/ bulldozing, and two-stage growth), each with their own distinct deformation style. Compressional structures likely dominate during radial growth (bulldozing) emplacement, while extensional structures are more likely to form during two-stage growth emplacement. In this study we focus on deformation structures (faults, deformation bands and joints) associated with emplacement of Tertiary sills and laccolith intrusions in the Henry Mountains, Utah. Trachyte Mesa, the most distal satellite intrusion to the Mt. Hilliers intrusive centre, is an elongate (NE-SW) laccolith concordant with the Entrada sandstone it intrudes. The intrusion is comprised of multiple, stacked intrusive sheets. Two structural transects across the northwest lateral margin have identified distinct structural domains within the host rock that reflect both temporal and kinematic variations in deformation. Three deformation phases are identified, interpreted to be pre-, syn- and late-emplacement structures. A background set of deformation bands (phase 1), trending oblique to the intrusion margin, is apparent across the entire area. A second set of deformation bands (phase 2) overprint the early phase. These are characterised by conjugate deformation bands that parallel the intrusion margin, and increase in intensity and spacing towards the intrusion. Within this same zone a series of calcite filled normal faults, striking parallel and perpendicular to the intrusion margin, are apparent. Due to their spatial, kinematic and overprinting relationships we interpret these to be linked to the emplacement of the intrusive body. Overprinting all other structures, are two sets of tensile joints
DEA deformed stretchable patch antenna
International Nuclear Information System (INIS)
A stretchable patch antenna (SPA) whose frequency is tuned by a planar dielectric elastomer actuator (DEA) is presented in this paper. This mechanically reconfigurable antenna system has a configuration resembling a pre-stretched silicone belt. Part of the belt is embedded with a layer of conductive liquid metal to form the patch antenna. Part of the belt is sandwiched between conductive electrodes to form the DEA. Electrical activation of the DEA results in a contraction of the patch antenna, and as a result, in a variation of its resonance frequency. Design and fabrication steps of this system are presented. Measurement results for deformation, resonance frequency variation and efficiency of the patch antenna are also presented. (paper)
Deformation of Linked Polymer Coils
Institute of Scientific and Technical Information of China (English)
董朝霞; 李明远; 吴肇亮; 林梅钦
2003-01-01
Linked polymer solution (LPS) is defined as the solution of linked polymer coils (LPCs) dispersed in water, composed of low concentration partially hydrolyzed polyacrylamide (HPAM) and aluminum citrate (crosslinker). In the work, the conformational changes of LPCs under different conditions were investigated by the methods of membrane filtering under low pressure, dynamic light scattering and core flooding experiments. The results showed that in some conditions the LPCs could be compressed mechanically to 1/158.5 of their original volume because of relatively lower HPAM cross-linking. The hydration property of LPCs was similar to that of normal polymer coils. The deformation of LPCs was more restricted than that of ordinary polymer coils under the flow shear stress or the shift of hydration equilibrium caused in the variation of the electrolyte concentration which is responsible for the effective plugging in the throats of porous media when LPCs are used for deep diverting.
Plastic deformation of nanocrystalline nickel
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
A high-resolution electron microscopy study has uncovered the plastic behavior of accommodating large strains in nanocrystalline (NC) Ni subject to cold rolling at liquid nitrogen temperature. The activation of grain-boundary-mediated-plasticity is evidenced in NC-Ni, including twinning and formation of stacking fault via partial dislocation slips from the grain boundary. The formation and storage of 60? full dislocations are observed inside NC-grains. The grain/twin boundaries act as the barriers of dislocation slips, leading to dislocation pile-up, severe lattice distortion, and formation of sub-grain boundary. The vicinity of grain/twin boundary is where defects preferentially accumulate and likely the favorable place for onset of plastic deformation. The present results indicate the heterogeneous and multiple natures of accommodating plastic strains in NC-grains.
Spectral descriptors for deformable shapes
Bronstein, Alexander M
2011-01-01
Informative and discriminative feature descriptors play a fundamental role in deformable shape analysis. For example, they have been successfully employed in correspondence, registration, and retrieval tasks. In the recent years, significant attention has been devoted to descriptors obtained from the spectral decomposition of the Laplace-Beltrami operator associated with the shape. Notable examples in this family are the heat kernel signature (HKS) and the wave kernel signature (WKS). Laplacian-based descriptors achieve state-of-the-art performance in numerous shape analysis tasks; they are computationally efficient, isometry-invariant by construction, and can gracefully cope with a variety of transformations. In this paper, we formulate a generic family of parametric spectral descriptors. We argue that in order to be optimal for a specific task, the descriptor should take into account the statistics of the corpus of shapes to which it is applied (the "signal") and those of the class of transformations to whi...
Precise Object Tracking under Deformation
International Nuclear Information System (INIS)
The precise object tracking is an essential issue in several serious applications such as; robot vision, automated surveillance (civil and military), inspection, biomedical image analysis, video coding, motion segmentation, human-machine interface, visualization, medical imaging, traffic systems, satellite imaging etc. This framework focuses on the precise object tracking under deformation such as scaling, rotation, noise, blurring and change of illumination. This research is a trail to solve these serious problems in visual object tracking by which the quality of the overall system will be improved. Developing a three dimensional (3D) geometrical model to determine the current pose of an object and predict its future location based on FIR model learned by the OLS. This framework presents a robust ranging technique to track a visual target instead of the traditional expensive ranging sensors. The presented research work is applied to real video stream and achieved high precession results. xiiiThe precise object tracking is an essential issue in several serious applications such as; robot vision, automated surveillance (civil and military), inspection, biomedical image analysis, video coding, motion segmentation, human-machine interface, visualization, medical imaging, traffic systems, satellite imaging etc. This framework focuses on the precise object tracking under deformation such as scaling, rotation, noise, blurring and change of illumination. This research is a trail to solve these serious problems in visual object tracking by which the quality of the overall system will be improved. Developing a three dimensional (3D) geometrical model to determine the current pose of an object and predict its future location based on FIR model learned by the OLS. This framework presents a robust ranging technique to track a visual target instead of the traditional expensive ranging sensors. The presented research work is applied to real video stream and achieved high
Developing a Virtual Rock Deformation Laboratory
Zhu, W.; Ougier-simonin, A.; Lisabeth, H. P.; Banker, J. S.
2012-12-01
Experimental rock physics plays an important role in advancing earthquake research. Despite its importance in geophysics, reservoir engineering, waste deposits and energy resources, most geology departments in U.S. universities don't have rock deformation facilities. A virtual deformation laboratory can serve as an efficient tool to help geology students naturally and internationally learn about rock deformation. Working with computer science engineers, we built a virtual deformation laboratory that aims at fostering user interaction to facilitate classroom and outreach teaching and learning. The virtual lab is built to center around a triaxial deformation apparatus in which laboratory measurements of mechanical and transport properties such as stress, axial and radial strains, acoustic emission activities, wave velocities, and permeability are demonstrated. A student user can create her avatar to enter the virtual lab. In the virtual lab, the avatar can browse and choose among various rock samples, determine the testing conditions (pressure, temperature, strain rate, loading paths), then operate the virtual deformation machine to observe how deformation changes physical properties of rocks. Actual experimental results on the mechanical, frictional, sonic, acoustic and transport properties of different rocks at different conditions are compiled. The data acquisition system in the virtual lab is linked to the complied experimental data. Structural and microstructural images of deformed rocks are up-loaded and linked to different deformation tests. The integration of the microstructural image and the deformation data allows the student to visualize how forces reshape the structure of the rock and change the physical properties. The virtual lab is built using the Game Engine. The geological background, outstanding questions related to the geological environment, and physical and mechanical concepts associated with the problem will be illustrated on the web portal. In
Effect of torsional deformation on the recrystallization of bubble strengthened tungsten
International Nuclear Information System (INIS)
The effect of torsional deformation on the recrystallization temperature and grain morphology of 0.39 mm diameter KSiAl-doped tungsten wires was investigated at different strains. The movement of the grain boundaries and the temperature at which exaggerated grain growth started were studied by emission electron microscopy. As a result of the applied twists, the onset of grain growth was shifted to lower temperatures leading to the formation of relatively small grains with low aspect ratios, while the long axis of the grains were oriented at high angles to the wire axis depending on the amount of deformation. The observations are explained by a deformation-induced disturbance and coarsening of the original bubble dispersion resulting in a reduction of the pinning force during recrystallization. (orig.)
Recrystallization behaviour of fine-grained magnesium alloy after hot deformation
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Annealing behaviors of hot-deformed magnesium alloy AZ31 were studied at temperatures from 300 to 673 K by optical and SEM/EBSD metallographic observation. Temperature dependence of the average grain size(D) is categorized into three temperature regions, i.e. an incubation period for grain growth, rapid grain coarsening, and normal grain growth. The number of fine grains per unit area, however, is reduced remarkably even in incubation period. This leads to grain coarsening taking place continuously in the whole temperature regions. In contrast, the deformation texture scarcely changes even after full annealing at high temperatures. It is concluded that the annealing processes operating in hot-deformed magnesium alloy with continuous dynamic recrystallized grain structures can be mainly controlled by grain coarsening accompanied with no texture change, that is, continuous static recrystallization.
Transformation mechanism of deformation - induced compact martensite in Fe-Ni-C alloys
International Nuclear Information System (INIS)
Compact deformation - induced martensite found in Fe - 25Ni - 0.66C alloys has been studied by using optical, electron and scanning electron microscopy. The compact martensite consists of a large number of martensites with different variants connected closely to form large bulk in which almost no residual austenite remains. Its formation process is by further growth of thin plates to form lenticular plates and possible crossing and coalesence to form bulky martensite. These growth and coalesence are through martensitic twinning or twinning domains during deformation which leads to various interactions between the plates including cross, insert, coalescence and conversion. The substructure of the martensite is a crisscross twinning net. The corresponding deformation modes of the austenite are also studied. (orig.)
Numerical modeling of deformation in salt basins: Technical report
International Nuclear Information System (INIS)
The report describes the dominant physical mechanisms and the material properties influence in the formation of natural salt deformation features within a salt basin. Numerical analysis techniques include one-dimensional, closed-form analytical solutions; one-dimensional analytical solutions employing a numerical propagator matrix technique; and a two-dimensional, finite-element, viscoplastic numerical code (MANTLE). The published works of earlier investigators were reviewed, along with conventional applications of the one-dimensional, closed-form solutions. Earlier work was extended to more complex multilayered, thin interbed systems, using a numerical propagator matrix. Nonlinear salt properties and two-dimensional mechanisms were modeled, including horizontal tectonic strain, predeposition-of-salt basement faulting, and postdeposition-of-salt basement faulting, with vertical shear stress produced in the overlying salt. The study concludes that the conventional analyses using assumed effective viscosities for salt and density-inversion mechanics are incorrect, first-order or major perturbations in a bedded salt formation require the application of shear stress to initiate the appropriate growth rate, a condition of postdeposition basement faulting is the probable mechanism to initiate such shear stress, and interbed and internal salt fabric (second-order and higher) deformation characteristics can be strongly asymmetric to the major deformation surfaces in the region of basement faulting/shear stress location. 28 refs., 70 figs., 3 tabs
The correction of complex foot deformities using Ilizarov's distraction osteotomies.
Paley, D
1993-08-01
Twenty-five very complex foot deformities were treated by Ilizarov distraction osteotomies. The osteotomy types included supramalleolar, U, V, posterior calcaneal, talocalcaneal neck, midfoot, and metatarsal osteotomies. In addition, the leg was lengthened and widened in most cases. The mean treatment time was 6.4 months. There were 20 minor or major complications related to the foot osteotomies in 18 feet, including deep pin-tract infection in three, failure of osteotomy separation in nine, acute postoperative tarsal tunnel syndrome in two, toe contractures in three, wire breakage or cutout in two, and buckle fracture in one. Nineteen secondary procedures were required in 13 patients to treat these complications. The final result was a plantigrade foot in 22 in late follow-up evaluation. The three nonplantigrade feet were attributable to unrecognized heel varus in one, ball and socket ankle joint in one, and partial growth arrest progressive deformity in one. Gait was improved in all cases. Pain was eliminated in all but two patients. Based on these criteria, the results were judged to be satisfactory in 22 and unsatisfactory in three. The Ilizarov method can successfully correct complex foot deformities despite complications. PMID:8339516
GPS and EDM monitoring of Unzen volcano ground deformation
Matsushima, Takeshi; Takagi, Akimichi
2000-11-01
Following 198 years of dormancy, an eruption started at Mt. Fugen, the main peak of Unzen volcano, in Kyushu, Japan, in November 1990. A dacite lava dome began to grow in May 1991. We installed the surveying points of GPS in 1992 around the lava dome in order to observe the ground deformation that accompanied the growth of the lava dome. In the winters of 1993 and 1994, we observed swift ground deformations that radiated from the vent of the volcano. It was presumed that rising magma accumulated and expanded the volcano body. After the lava effusion stopped in 1995, we also installed surveying points on the lava dome. EDM mirrors were permanently fixed to the large rocks with bolts. A GPS survey was carried out 2 or 3 times each year to estimate the 3-dimensional displacement. The result of the EDM survey showed that the baselines from the flank of the volcano were shortening 5 mm per day, and the result of the GPS survey showed that the displacement vector of the dome was parallel to the direction of the steepest slope of the old volcano body. This indicates that the inside of the lava dome is still very hot, and that deformation of the dome is viscous.
Deformed Exponentials and Applications to Finance
Directory of Open Access Journals (Sweden)
Barbara Trivellato
2013-09-01
Full Text Available We illustrate some financial applications of the Tsallis and Kaniadakis deformed exponential. The minimization of the corresponding deformed divergence is discussed as a criterion to select a pricing measure in the valuation problems of incomplete markets. Moreover, heavy-tailed models for price processes are proposed, which generalized the well-known Black and Scholes model.
Constitutive model with time-dependent deformations
DEFF Research Database (Denmark)
Krogsbøll, Anette
1998-01-01
common in time as well as size. This problem is adressed by means of a new constitutive model for soils. It is able to describe the behavior of soils at different deformation rates. The model defines time-dependent and stress-related deformations separately. They are related to each other and they occur...
Plate-tectonic mechanism of Laramide deformation.
Hamilton, W.
1981-01-01
The Laramide compressive deformation of the craton was caused by a clockwise rotation of about 2-4o of the Colorado Plateau region relative to the continental interior, during late Late Cretaceous and early Tertiary time. Late Paleozoic and Neogene deformation of the craton also were produced by motion of a southwestern subplate relative to the continental interior. -from Author
Miniversal Deformations of Bimodal Picewise Linear Systems
Ferrer Llop, Josep; Magret Planas, Maria dels Dolors; Pacha Andújar, Juan Ramón; Peña Carrera, Marta
2010-01-01
Keywords: Bimodal piecewise linear system, miniversal deformations, reduced forms. Bimodal linear systems are those consisting of two linear systems on each side of a given hyperplane, having continuous dynamics along that hyperplane. In this work, we focus on the derivation of (orthogonal) miniversal deformations, by using reduced forms.
A Simple Deformation of Special Relativity
Heuson, C
2003-01-01
A deformation of special relativity based on a dispersion relation with an energy independent speed of light and a symmetry between positive and negative energy states is proposed. The deformed Lorentz transformations, generators and algebra are derived and some consequences are discussed.
Cyclic Plastic Deformation and Welding Simulation
Ten Horn, C.H.L.J.
2003-01-01
One of the concerns of a fitness for purpose analysis is the quantification of the relevant material properties. It is known from experiments that the mechanical properties of a material can change due to a monotonic plastic deformation or a cyclic plastic deformation. For a fitness for purpose anal
The q-Deformed NJL Model "Revisited"
Avancini, S S; Peres-Menezes, D; Watanabe de Moraes, M M
2001-01-01
In this work we investigate the chiral symmetry breaking in the q-deformed version of the NJL Model and its consequent mass generation mechanism . We show that the deformation of the NJL model, in the mean field approximation, may take into account correlations that go beyond the mean field and, in a certain limit, approaches the more realistic lattice calculations.
Einstein-Riemann Gravity on Deformed Spaces
Julius Wess
2006-01-01
A differential calculus, differential geometry and the E-R Gravity theory are studied on noncommutative spaces. Noncommutativity is formulated in the star product formalism. The basis for the gravity theory is the infinitesimal algebra of diffeomorphisms. Considering the corresponding Hopf algebra we find that the deformed gravity is based on a deformation of the Hopf algebra.
Deformation of the great coupling diaphragms
Directory of Open Access Journals (Sweden)
Tomasz ZAJĄC
2007-01-01
Full Text Available Plastic deformation mode of the great coupling diaphragms is the subjectmatter of this article. The model has been created on the experimental way through the research on a wheel excavator. The presented analysis algorithm of the aggregated data is a basis for identification of the causes and the area of the plastic deformation in the great coupling diaphragms.
Cyclic Shearing Deformation Behavior of Saturated Clays
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The apparatus for static and dynamic universal triaxial and torsional shear soil testing is employed to perform stress-controlled cyclic single-direction torsional shear tests and two-direction coupled shear tests under unconsolidated-undrained conditions. Through a series of tests on saturated clay, the effects of initial shear stress and stress reversal on the clay's strain-stress behavior are examined, and the behavior of pore water pressure is studied. The experimental results indicate that the patterns of stress-strain relations are distinctly influenced by the initial shear stress in the cyclic single-direction shear tests. When the initial shear stress is large and no stress reversal occurs, the predominant deformation behavior is characterized by an accumulative effect. When the initial shear stress is zero and symmetrical cyclic stress occurs, the predominant deformation behavior is characterized by a cyclic effect. The pore water pressure fluctuates around the confining pressure with the increase of cycle number. It seems that the fluctuating amplitude increases with the increase of the cyclic stress. But a buildup of pore water pressure does not occur. The deformations of clay samples under the complex initial and the cyclic coupled stress conditions include the normal deviatoric deformation and horizontal shear deformation, the average deformation and cyclic deformation. A general strain failure criterion taking into account these deformations is recommended and is proved more stable and suitable compared to the strain failure criteria currently used.
Complementary energy principle for large elastic deformation
Institute of Scientific and Technical Information of China (English)
GAO; Yuchen
2006-01-01
Using the "base forces" as the fundamental unknowns to determine the state of an elastic system, the complementary energy principle for large elastic deformation is constructed for the conjugate quantities being displacement gradients, which possesses exactly the same form as that of classical linear elasticity. It is revealed that the complementary energy contains deformation part and rotation part.
Deformed metals - structure, recrystallisation and strength
DEFF Research Database (Denmark)
Hansen, Niels; Juul Jensen, Dorte
2011-01-01
It is shown how new discoveries and advanced experimental techniques in the last 25 years have led to paradigm shifts in the analysis of deformation and annealing structures of metals and in the way the strength of deformed samples is related to structural parameters. This is described in three s...
Solute transport through a deforming porous medium
Peters, Glen P.; Smith, David W.
2002-06-01
Solute transport through a porous medium is typically modelled assuming the porous medium is rigid. However, many applications exist where the porous medium is deforming, including, municipal landfill liners, mine tailings dams, and land subsidence. In this paper, mass balance laws are used to derive the flow and transport equations for a deforming porous medium. The equations are derived in both spatial and material co-ordinate systems. Solute transport through an engineered landfill liner is used as an illustrative example to show the differences between the theory for a rigid porous medium, and small and large deformation analysis of a deforming porous medium. It is found that the large deformation model produces shorter solute breakthrough times, followed by the small deformation model, and then the rigid porous medium model. It is also found that it is important to include spatial and temporal void ratio variations in the large deformation analysis. It is shown that a non-linear large deformation model may greatly reduce the solute breakthrough time, compared to a standard transport analysis typically employed by environmental engineers.
Deformed Ginibre ensembles and integrable systems
Energy Technology Data Exchange (ETDEWEB)
Orlov, A.Yu., E-mail: orlovs@ocean.ru
2014-01-17
We consider three Ginibre ensembles (real, complex and quaternion-real) with deformed measures and relate them to known integrable systems by presenting partition functions of these ensembles in form of fermionic expectation values. We also introduce double deformed Dyson–Wigner ensembles and compare their fermionic representations with those of Ginibre ensembles.
ACCUMULATED DEFORMATION MODELING OF PERMANENT WAY BASED ON ENTROPY SYSTEM
Directory of Open Access Journals (Sweden)
D. M. Kurhan
2015-07-01
Full Text Available Purpose. The work provides a theoretical research about the possibility of using methods that determine the lifetime of a railway track not only in terms of total stresses, and accounting its structure and dynamic characteristics. The aim of these studies is creation the model of deformations accumulation for assessment of service life of a railway track taking into account these features. Methodology. To simulate a gradual change state during the operation (accumulation of deformations the railway track is presented as a system that consists of many particles of different materials collected in a coherent design. It is appropriate to speak not about the appearance of deformations of a certain size in a certain section of the track, and the probability of such event on the site. If to operate the probability of occurrence of deviations, comfortable state of the system is characterized by the number of breaks of the conditional internal connections. The same state of the system may correspond to different combinations of breaks. The more breaks, the more the number of options changes in the structure of the system appropriate to its current state. Such a process can be represented as a gradual transition from an ordered state to a chaotic one. To describe the characteristics of the system used the numerical value of the entropy. Findings. Its entropy is constantly increasing at system aging. The growth of entropy is expressed by changes in the internal energy of the system, which can be determined using mechanical work forces, which leads to deformation. This gives the opportunity to show quantitative indication of breaking the bonds in the system as a consequence of performing mechanical work. According to the results of theoretical research methods for estimation of the timing of life cycles of railway operation considering such factors as the structure of the flow of trains, construction of the permanent way, the movement of trains at high
The deformed uncertainty relation and the corresponding beam quality factor
Li, K; Wang, S M; Li, Kang; Zhao, Dao Mu; Wang, Shao Min
1996-01-01
By using the theory of deformed quantum mechanics, we study the deformed light beam theoretically. The deformed beam quality factor M_q^2 is given explicitly under the case of deformed light in coherent state. When the deformation parameter q being a root of unity, the beam quality factor M_q^2 \\leq 1.
Hot deformation behavior of FGH96 superalloys
Institute of Scientific and Technical Information of China (English)
Jiantao Liu; Guoquan Liu; Benfu Hu; Yuepeng Song; Ziran Qin; Yiwen Zhang
2006-01-01
The hot deformation behavior of FGH96 superalloys at 1070-1170℃ and 5×10-4-2×10-1 s-1 were investigated by means of the isothermal compression tests at a Gleeble-1500 thermal mechanical simulator. The results show that dynamic recovery acts as the main softening mechanism below 2×10-3 s-1, whereas dynamic recrystallization acts as the main softening mechanism above 2×10-3 s-1during deformation; the temperature increase caused by the deformation and the corresponding softening stress is negligible; the thermal-mechanical constitutive model to describe the hot deformation behavior is given, and the value of the apparent deformation activation energy (Qdef) is determined to be 354.93 kJ/mol.
Deformation of fuel cans in Phenix reactor
International Nuclear Information System (INIS)
The Phenix reactor has functioned for your years in satisfactory conditions. The first two assembly charges include fuel rods clad in hyper quenched 316 steel. The main fuel rod deformations are: diametrical deformation (swelling and irradiation creep), ovalizing and helical bending of the cladding (wire-cladding and bundle-hexagonal tube interaction). A bundle of fuel rods irradiated at a dose of 80F atomic displacement reaches a 5% diametrical deformation of the cladding. This deformation is mainly swelling (low fission gas pressure). The principal parameters governing the swelling are the instantaneous dose, time and temperature for a given cladding grade. Other grades of steel are being irradiated in Phenix or will be. Titanium stabilized cold rolled 316 steel in particular should help to reduce cladding deformation and increase the normal burnup in this reactor
Refined Cigar and Omega-deformed Conifold
Nakayama, Yu
2010-01-01
Antoniadis et al proposed a relation between the Omega-deformation and refined correlation functions of the topological string theory. We investigate the proposal for the deformed conifold geometry from a non-compact Gepner model approach. The topological string theory on the deformed conifold has a dual description in terms of the c=1 non-critical string theory at the self-dual radius, and the Omega-deformation yields the radius deformation. We show that the refined correlation functions computed from the twisted SL(2,R)/U(1) Kazama-Suzuki coset model at level k=1 have direct c=1 non-critical string theory interpretations. After subtracting the leading singularity to procure the 1PI effective action, we obtain the agreement with the proposal.
Lunin-Maldacena deformations with three parameters
International Nuclear Information System (INIS)
We examine the solution generating symmetries by which Lunin and Maldacena have generated the gravity duals of β-deformations of certain field theories. We identify the O(2,2,R) matrix, which acts on the background matrix E = g+B, where g and B are the metric and the B-field of the undeformed background, respectively. This simplifies the calculations and makes some features of the deformed backgrounds more transparent. We also find a new three-parameter deformation of the Sasaki-Einstein manifolds T1,1 and Yp,q. Following the recent literature on the three-parameter deformation of AdS5 x S5, one would expect that our new solutions should correspond to non-supersymmetric marginal deformations of the relevant dual field theories
Large deformations of a soft porous material
MacMinn, Christopher W; Wettlaufer, John S
2015-01-01
Compressing a porous material will decrease the volume of pore space, driving fluid out. Similarly, injecting fluid into a porous material can drive mechanical deformation, distorting the solid skeleton. This poromechanical coupling has applications ranging from cell and tissue mechanics to geomechanics and hydrogeology. The classical theory of linear poroelasticity captures this coupling by combining Darcy's law with linear elasticity and then further linearizing in the strain. This is a good model for very small deformations, but it becomes increasingly inappropriate as deformations grow larger, and moderate to large deformations are common in the context of phenomena such as swelling or damage, or for materials that are extremely soft. Here, we first review a rigorous Eulerian framework for large-deformation poromechanics. We then compare the predictions of linear poroelasticity with those of fully nonlinear poromechanics in the context of two uniaxial model problems: Fluid outflow driven by an applied mec...
Scoliosis and tibiotarsal deformities in broiler chickens.
Droual, R; Bickford, A A; Farver, T B
1991-01-01
The incidence and degree of scoliosis were investigated in broiler chickens with and without intertarsal deformities associated with slipped gastrocnemius tendons. In both groups, the incidence of scoliosis was similar and there was a significant tendency for scoliosis to be convex on the right side. However, scoliosis was significantly greater in birds with intertarsal deformities, and in a significant proportion of these the joint with a slipped tendon was on the convex side of scoliosis. In birds with deformities, inequalities between right and left tibiotarsi were significantly greater, and tibiotarsi with greater length, narrower condyles and trochleae, and shallower trochlear grooves were significantly more often on the convex side of scoliosis. Significant positive correlations were found between scoliosis and rotational and bending deformities of the distal tibiotarsus on the convex side of scoliosis. These findings suggest a cause-and-effect relationship between scoliosis and tibiotarsal deformities associated with slipped tendons. PMID:2029256
Deformation mechanisms in cyclic creep and fatigue
International Nuclear Information System (INIS)
Service conditions in which static and cyclic loading occur in conjunction are numerous. It is argued that an understanding of cyclic creep and cyclic deformation are necessary both for design and for understanding creep-fatigue fracture. Accordingly a brief, and selective, review of cyclic creep and cyclic deformation at both low and high strain amplitudes is provided. Cyclic loading in conjunction with static loading can lead to creep retardation if cyclic hardening occurs, or creep acceleration if softening occurs. Low strain amplitude cyclic deformation is understood in terms of dislocation loop patch and persistent slip band behavior, high strain deformation in terms of dislocation cell-shuttling models. While interesting advances in these fields have been made in the last few years, the deformation mechanisms are generally poorly understood
The properties of Q-deformed hyperbolic and trigonometric functions in quantum deformation
International Nuclear Information System (INIS)
Quantum deformation has been studied due to its relation with applications in nuclear physics, conformal field theory, and statistical-quantum theory. The q-deformation of hyperbolic function was introduced by Arai. The application of q-deformed functions has been widely used in quantum mechanics. The properties of this two kinds of system explained in this paper including their derivative. The graph of q-deformed functions presented using Matlab. The special case is given for modified Poschl-Teller plus q-deformed Scarf II trigonometry potentials
The properties of Q-deformed hyperbolic and trigonometric functions in quantum deformation
Deta, U. A.; Suparmi
2015-09-01
Quantum deformation has been studied due to its relation with applications in nuclear physics, conformal field theory, and statistical-quantum theory. The q-deformation of hyperbolic function was introduced by Arai. The application of q-deformed functions has been widely used in quantum mechanics. The properties of this two kinds of system explained in this paper including their derivative. The graph of q-deformed functions presented using Matlab. The special case is given for modified Poschl-Teller plus q-deformed Scarf II trigonometry potentials.
Large Deformations of a Soft Porous Material
MacMinn, Christopher W.; Dufresne, Eric R.; Wettlaufer, John S.
2016-04-01
Compressing a porous material will decrease the volume of the pore space, driving fluid out. Similarly, injecting fluid into a porous material can expand the pore space, distorting the solid skeleton. This poromechanical coupling has applications ranging from cell and tissue mechanics to geomechanics and hydrogeology. The classical theory of linear poroelasticity captures this coupling by combining Darcy's law with Terzaghi's effective stress and linear elasticity in a linearized kinematic framework. Linear poroelasticity is a good model for very small deformations, but it becomes increasingly inappropriate for moderate to large deformations, which are common in the context of phenomena such as swelling and damage, and for soft materials such as gels and tissues. The well-known theory of large-deformation poroelasticity combines Darcy's law with Terzaghi's effective stress and nonlinear elasticity in a rigorous kinematic framework. This theory has been used extensively in biomechanics to model large elastic deformations in soft tissues and in geomechanics to model large elastoplastic deformations in soils. Here, we first provide an overview and discussion of this theory with an emphasis on the physics of poromechanical coupling. We present the large-deformation theory in an Eulerian framework to minimize the mathematical complexity, and we show how this nonlinear theory simplifies to linear poroelasticity under the assumption of small strain. We then compare the predictions of linear poroelasticity with those of large-deformation poroelasticity in the context of two uniaxial model problems: fluid outflow driven by an applied mechanical load (the consolidation problem) and compression driven by a steady fluid throughflow. We explore the steady and dynamical errors associated with the linear model in both situations, as well as the impact of introducing a deformation-dependent permeability. We show that the error in linear poroelasticity is due primarily to kinematic
Incipient deformation twinning in dynamically sheared bcc tantalum
International Nuclear Information System (INIS)
Mechanical twinning has been introduced into a body-centered cubic metal, tantalum, through shear-dominant dynamic loading at a high shear strain rate (up to 3 × 104/s) at 77 K. Direct measurement of shear stress combined with transmission electron microscopy (TEM) confirmed the occurrence of deformation twinning at applied global shear stresses of 520 MPa and above. The TEM characterization was focused on nanometer-sized individual twins that are interspersed and aligned in association with slip bands. These small twins belong to the {1 1 2}〈111¯〉 twinning system but show unusual morphologies and growth characteristics, and are believed to be incipient twins at the early stages of their development. TEM analysis revealed a multifaceted growth characteristic of the incipient twins following at least two {1 1 2} planes in the 〈111¯〉 zone. While the formation of a macroscopic twin is a result of growth and coalescence of an array of small twins, the early stage growth of an incipient twin is rationalized through a slip-assisted double-cross-slip growth mechanism
Auzende, Anne-Line; Escartin, Javier; Walte, Nicolas P.; Guillot, Stéphane; Hirth, Greg; Frost, Daniel J.
2015-02-01
We performed deformation-DIA experiments on antigorite serpentinite at pressures of 1-3.5 GPa and temperatures of between 400 and 650 °C, bracketing the stability of antigorite under subduction zone conditions. For each set of pressure-temperature (P-T) conditions, we conducted two runs at strain rates of 5 ×10-5 and 1 ×10-4 s-1. We complemented our study with a sample deformed in a Griggs-type apparatus at 1 GPa and 400 °C (Chernak and Hirth, 2010), and with natural samples from Cuba and the Alps deformed under blueschist/eclogitic conditions. Optical and transmission electron microscopies were used for microstructural characterization and determination of deformation mechanisms. Our observations on experimentally deformed antigorite prior to breakdown show that deformation is dominated by cataclastic flow with observable but minor contribution of plastic deformation (microkinking and (001) gliding mainly expressed by stacking disorder mainly). In contrast, in naturally deformed samples, plastic deformation structures are dominant (stacking disorder, kinking, pressure solution), with minor but also perceptible contribution of brittle deformation. When dehydration occurs in experiments, plasticity increases and is coupled to local embrittlement that we attribute to antigorite dehydration. In dehydrating samples collected in the Alps, embrittlement is also observed suggesting that dehydration may contribute to intermediate-depth seismicity. Our results thus show that semibrittle deformation operates within and above the stability field of antigorite. However, the plastic deformation recorded by naturally deformed samples was likely acquired at low strain rates. We also document that the corrugated structure of antigorite controls the strain accommodation mechanisms under subduction conditions, with preferred inter- and intra-grain cracking along (001) and gliding along both a and b. We also show that antigorite rheology in subduction zones is partly controlled
Mathematical textbook of deformable neuroanatomies.
Miller, M I; Christensen, G E; Amit, Y; Grenander, U
1993-12-15
Mathematical techniques are presented for the transformation of digital anatomical textbooks from the ideal to the individual, allowing for the representation of the variabilities manifest in normal human anatomies. The ideal textbook is constructed on a fixed coordinate system to contain all of the information currently available about the physical properties of neuroanatomies. This information is obtained via sensor probes such as magnetic resonance, as well as computed axial and emission tomography, along with symbolic information such as white- and gray-matter tracts, nuclei, etc. Human variability associated with individuals is accommodated by defining probabilistic transformations on the textbook coordinate system, the transformations forming mathematical translation groups of high dimension. The ideal is applied to the individual patient by finding the transformation which is consistent with physical properties of deformable elastic solids and which brings the coordinate system of the textbook to that of the patient. Registration, segmentation, and fusion all result automatically because the textbook carries symbolic values as well as multisensor features. PMID:8265653
Weak associativity and deformation quantization
Directory of Open Access Journals (Sweden)
V.G. Kupriyanov
2016-09-01
Full Text Available Non-commutativity and non-associativity are quite natural in string theory. For open strings it appears due to the presence of non-vanishing background two-form in the world volume of Dirichlet brane, while in closed string theory the flux compactifications with non-vanishing three-form also lead to non-geometric backgrounds. In this paper, working in the framework of deformation quantization, we study the violation of associativity imposing the condition that the associator of three elements should vanish whenever each two of them are equal. The corresponding star products are called alternative and satisfy important for physical applications properties like the Moufang identities, alternative identities, Artin's theorem, etc. The condition of alternativity is invariant under the gauge transformations, just like it happens in the associative case. The price to pay is the restriction on the non-associative algebra which can be represented by the alternative star product, it should satisfy the Malcev identity. The example of nontrivial Malcev algebra is the algebra of imaginary octonions. For this case we construct an explicit expression of the non-associative and alternative star product. We also discuss the quantization of Malcev–Poisson algebras of general form, study its properties and provide the lower order expression for the alternative star product. To conclude we define the integration on the algebra of the alternative star products and show that the integrated associator vanishes.
Capillary Deformations of Bendable Films
Schroll, R. D.
2013-07-01
We address the partial wetting of liquid drops on ultrathin solid sheets resting on a deformable foundation. Considering the membrane limit of sheets that can relax compression through wrinkling at negligible energetic cost, we revisit the classical theory for the contact of liquid drops on solids. Our calculations and experiments show that the liquid-solid-vapor contact angle is modified from the Young angle, even though the elastic bulk modulus (E) of the sheet is so large that the ratio between the surface tension γ and E is of molecular size. This finding indicates a new elastocapillary phenomenon that stems from the high bendability of very thin elastic sheets rather than from material softness. We also show that the size of the wrinkle pattern that emerges in the sheet is fully predictable, thus resolving a puzzle in modeling "drop-on-a-floating-sheet" experiments and enabling a quantitative, calibration-free use of this setup for the metrology of ultrathin films. © 2013 American Physical Society.
Capillary deformations of bendable films.
Schroll, R D; Adda-Bedia, M; Cerda, E; Huang, J; Menon, N; Russell, T P; Toga, K B; Vella, D; Davidovitch, B
2013-07-01
We address the partial wetting of liquid drops on ultrathin solid sheets resting on a deformable foundation. Considering the membrane limit of sheets that can relax compression through wrinkling at negligible energetic cost, we revisit the classical theory for the contact of liquid drops on solids. Our calculations and experiments show that the liquid-solid-vapor contact angle is modified from the Young angle, even though the elastic bulk modulus (E) of the sheet is so large that the ratio between the surface tension γ and E is of molecular size. This finding indicates a new elastocapillary phenomenon that stems from the high bendability of very thin elastic sheets rather than from material softness. We also show that the size of the wrinkle pattern that emerges in the sheet is fully predictable, thus resolving a puzzle in modeling "drop-on-a-floating-sheet" experiments and enabling a quantitative, calibration-free use of this setup for the metrology of ultrathin films. PMID:23863002
Deformability-based capsule sorting
Le Goff, Anne; Munier, Nadege; Maire, Pauline; Edwards-Levy, Florence; Salsac, Anne-Virginie
2015-11-01
Many microfluidic devices have been developed for cancer diagnosis applications, most of which relying on costly antibodies. Since some cancer cells display abnormal mechanical properties, new sorting tools based on mechanical sensing are of particular interest. We present a simple, passive pinched flow microfluidic system for capsule sorting. The device consists of a straight microchannel containing a cylindrical obstacle. Thanks to a flow-focusing module placed at the channel entrance, capsules arrive well-centered in the vicinity of the obstacle. Pure size-sorting can be achieved at low shear rate. When increasing the shear rate, capsules are deformed in the narrow space between the pillar and the wall. The softer the capsule, the more tightly it wraps around the obstacle. After the obstacle, streamlines diverge, allowing for the separation between soft capsules, that follow central streamlines, and stiff capsules, that drift away from the obstacle with a wider angle. This proves that we have developed a flexible multipurpose sorting microsystem based on a simple design.
Crustal deformation: Earth vs Venus
International Nuclear Information System (INIS)
It is timely to consider the possible tectonic regimes on Venus both in terms of what is known about Venus and in terms of deformation mechanisms operative on the earth. Plate tectonic phenomena dominate tectonics on the earth. Horizontal displacements are associated with the creation of new crust at ridges and destruction of crust at trenches. The presence of plate tectonics on Venus is debated, but there is certainly no evidence for the trenches associated with subduction on the earth. An essential question is what kind of tectonics can be expected if there is no plate tectonics on Venus. Mars and the Moon are reference examples. Volcanic constructs appear to play a dominant role on Mars but their role on Venus is not clear. On single plate planets and satellites, tectonic structures are often associated with thermal stresses. Cooling of a planet leads to thermal contraction and surface compressive features. Delamination has been propsed for Venus by several authors. Delamination is associated with the subduction of the mantle lithosphere and possibly the lower crust but not the upper crust. The surface manifestations of delamination are unclear. There is some evidence that delamination is occurring beneath the Transverse Ranges in California. Delamination will certainly lead to lithospheric thinning and is likely to lead to uplift and crustal thinning
Weak associativity and deformation quantization
Kupriyanov, V G
2016-01-01
Non-commutativity is quite natural in string theory. For open strings it appears due to the presence of non-vanishing background two-form in the world volume of Dirichlet brane, while in closed string theory the flux compactifications with non-vanishing three-form also lead to non-commutativity. Except for some specific cases, like the constant $B$-field in open strings, the string coordinates are not only non-commutative, but also non-associative. It manifests the non-geometric nature of the consistent string vacua. The aim of this paper is to study the mathematical tools necessary to deal with non-associativity in physics. Working in the framework of deformation quantization we admit non-associative star products, but keep the violation of associativity under control. We require that the star associator of three functions should vanish whenever each two of them are iqual. Such a star product is called alternative. This condition imposes the restriction on non-associative algebras, the star commutator should...
Weak associativity and deformation quantization
Kupriyanov, V. G.
2016-09-01
Non-commutativity and non-associativity are quite natural in string theory. For open strings it appears due to the presence of non-vanishing background two-form in the world volume of Dirichlet brane, while in closed string theory the flux compactifications with non-vanishing three-form also lead to non-geometric backgrounds. In this paper, working in the framework of deformation quantization, we study the violation of associativity imposing the condition that the associator of three elements should vanish whenever each two of them are equal. The corresponding star products are called alternative and satisfy important for physical applications properties like the Moufang identities, alternative identities, Artin's theorem, etc. The condition of alternativity is invariant under the gauge transformations, just like it happens in the associative case. The price to pay is the restriction on the non-associative algebra which can be represented by the alternative star product, it should satisfy the Malcev identity. The example of nontrivial Malcev algebra is the algebra of imaginary octonions. For this case we construct an explicit expression of the non-associative and alternative star product. We also discuss the quantization of Malcev-Poisson algebras of general form, study its properties and provide the lower order expression for the alternative star product. To conclude we define the integration on the algebra of the alternative star products and show that the integrated associator vanishes.
Nguyen, N H; Whatmore, P; Miller, A; Knibb, W
2016-02-01
The main aim of this study was to estimate the heritability for four measures of deformity and their genetic associations with growth (body weight and length), carcass (fillet weight and yield) and flesh-quality (fillet fat content) traits in yellowtail kingfish Seriola lalandi. The observed major deformities included lower jaw, nasal erosion, deformed operculum and skinny fish on 480 individuals from 22 families at Clean Seas Tuna Ltd. They were typically recorded as binary traits (presence or absence) and were analysed separately by both threshold generalized models and standard animal mixed models. Consistency of the models was evaluated by calculating simple Pearson correlation of breeding values of full-sib families for jaw deformity. Genetic and phenotypic correlations among traits were estimated using a multitrait linear mixed model in ASReml. Both threshold and linear mixed model analysis showed that there is additive genetic variation in the four measures of deformity, with the estimates of heritability obtained from the former (threshold) models on liability scale ranging from 0.14 to 0.66 (SE 0.32-0.56) and from the latter (linear animal and sire) models on original (observed) scale, 0.01-0.23 (SE 0.03-0.16). When the estimates on the underlying liability were transformed to the observed scale (0, 1), they were generally consistent between threshold and linear mixed models. Phenotypic correlations among deformity traits were weak (close to zero). The genetic correlations among deformity traits were not significantly different from zero. Body weight and fillet carcass showed significant positive genetic correlations with jaw deformity (0.75 and 0.95, respectively). Genetic correlation between body weight and operculum was negative (-0.51, P < 0.05). The genetic correlations' estimates of body and carcass traits with other deformity were not significant due to their relatively high standard errors. Our results showed that there are prospects for genetic
Thermal Microstructural Stability of AZ31 Magnesium after Severe Plastic Deformation
Energy Technology Data Exchange (ETDEWEB)
Young, John P.; Askari, Hesam A.; Hovanski, Yuri; Heiden, Michael J.; Field, David P.
2015-03-01
Both equal channel angular pressing and friction stir processing have the ability to refine the grain size of twin roll cast AZ31 magnesium and potentially improve its superplastic properties. This work used isochronal and isothermal heat treatments to investigate the microstructural stability of twin roll cast, equal channel angular pressed and friction stir processed AZ31 magnesium. For both heat treatment conditions, it was found that the twin roll casted and equal channel angular pressed materials were more stable than the friction stir processed material. Calculations of the grain growth kinetics showed that severe plastic deformation processing decreased the activation energy for grain boundary motion with the equal channel angular pressed material having the greatest Q value of the severely plastically deformed materials and that increasing the tool travel speed of the friction stir processed material improved microstructural stability. The Hollomon-Jaffe parameter was found to be an accurate means of identifying the annealing conditions that will result in substantial grain growth and loss of potential superplastic properties in the severely plastically deformed materials. In addition, Humphreys’s model of cellular microstructural stability accurately predicted the relative microstructural stability of the severely plastically deformed materials and with some modification, closely predicted the maximum grain size ratio achieved by the severely plastically deformed materials.
Dynamic strain ageing of deformed nitrogen-alloyed AISI 316 stainless steels
International Nuclear Information System (INIS)
Intergranular stress corrosion cracking has occurred in BWR environment in non-sensitized, deformed austenitic stainless steel materials. The affecting parameters are so far not fully known, but deformation mechanisms may be decisive. The effect of deformation and nitrogen content on the behaviour of austenitic stainless steels was investigated. The materials were austenitic stainless steels of AISI 316L type with different amounts of nitrogen (0.03 - 0.18%) and they were mechanically deformed 0, 5 and 20%. The investigations are focused on the dynamic strain ageing (DSA) behaviour. A few crack growth rate measurements are performed on nuclear grade AISI 316NG material with different degrees of deformation (0, 5 and 20%). The effects of DSA on mechanical properties of these materials are evaluated based on peaks in ultimate tensile strength and strain hardening coefficient and minimum in ductility in the DSA temperature range. Additionally, internal friction measurements have been performed in the temperature range of -100 to 600 deg. C for determining nitrogen interactions with other alloying elements and dislocations (cold-worked samples). The results show an effect of nitrogen on the stainless steel behaviour, e.g. clear indications of dynamic strain ageing and changes in the internal friction peaks as a function of nitrogen content and amount of deformation. (authors)
The study on the threshold strain of microvoid formation in TRIP steels during tensile deformation
International Nuclear Information System (INIS)
Highlights: ► The tensile mechanical behaviors of TRIP steels were studied under high rate deformation conditions. ► The threshold strain of microvoid formation was examined quantitatively. ► The effects of retained austenite of TRIP on suppressing microvoid formed during tensile process have been discussed. - Abstract: Transformation Induced Plasticity (TRIP) steels exhibit a better combination of strength and ductility properties than conventional high strength low alloy (HSLA) steels, and therefore receive considerable attention in the automotive industry. In this work, the tensile mechanical behaviors of TRIP-aided steels were studied under the condition of the quasi-static and high deformed rates. The deformed specimens were observed by scanning electron microscope (SEM) along the tensile axis. The threshold strain of microvoid formation was examined quantitatively according to the evolution of deformation. The results showed that: the yield and tensile strengths of TRIP steels increase with the strain rate, whereas their elongations decrease. However, the threshold strain for TRIP steels at high strain rate is larger than that at low strain rate. Comparing with the deformed microstructure and microvoids formed in the necking zone of dual phase (DP) steel, the progressive deformation-induced transformation of retained austenite in TRIP steels remarkably increases the threshold strain of microvoid formation and furthermore postpones its growth and coalescence.
Internal stresses and stored energy density in the grains at deformation of FCC-polycrystal
Kozlov, Eduard; Kiseleva, Svetlana; Popova, Nataliya; Koneva, Nina
2016-01-01
The distribution of internal stresses and the density of the accumulated energy in the deformed polycrystal austenitic steel were investigated. The internal stresses and the accumulated energy density were determined using the bend extinction contours observed on the deformed steel micrographs. The laws of internal stresses distributions and the accumulated energy density in the grains with various bending types were determined. At the deformation degrees ɛ = 14 % and ɛ = 25 % the average values of internal stresses and the accumulated energy density inside the individual grains with compound bending were higher than in the grains with simple bending. It testified the fact that the grains with compound bending were more stressed. At the increase of the steel deformation degree up to ɛ = 25 % the growth of contributions from additional modes observed on the internal stress distributions slowed down and at ɛ > 25 % the average internal stress decreased. The relaxation of internal stresses was due to the origin and increase of the microtwins volume fraction at the austenitic steel deformation. The presence of microtwins influenced the distributions of internal stresses and the accumulated energy density in the deformed polycrystal austenitic steel.
Deformation band and texture of a cast Mg-RE alloy under uniaxial hot compression
International Nuclear Information System (INIS)
Highlights: → The tendency of strain localization (deformation bands) increased with Z parameters. → Hot compression yielded out a randomized basal texture. → Localized deformation promoted dynamic precipitation within deformation bands. - Abstract: Microstructural evolution and texture of a cast Mg-9Gd-4Y-0.6Zr ingot under hot compression were studied in this paper. Post-deforming microstructures were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy, while crystallographic orientation information was obtained from X-Ray macro-texture measurement and EBSD micro-texture analysis. Dynamic recrystallization (DRX) initiated from the deformation bands (DB) forming on original grain boundaries; the DB became widen with continuously conversion of low-angle-boundary grains into high-angle-boundary grains. The tendency of strain localization increased with Z parameter. The macro-texture analysis indicates that uniaxial compression yielded out the randomized basal texture component. This texture component was found to be strengthened with increasing Z parameter. The micro-texture analysis shows that the deviation from the ideal basal texture arose from orientated growth within DBs. Moreover, the localization deformation promoted dynamic precipitation within DBs, which inhibited the development of DRX.
Molecular dynamics study of deformation and fracture in a tantalum nano-crystalline thin film
International Nuclear Information System (INIS)
We present results from molecular dynamics simulations of two nano-crystalline tantalum thin films that illuminate the variety of atomic-scale mechanisms of incipient plasticity. Sample 1 contains approximately 500 K atoms and 3 grains, chosen to facilitate study at 105 s−1 strain rate; sample 2 has 4.6 M atoms and 30 grains. The samples are loaded in uniaxial tension at deformation rates of 105–109 s−1, and display phenomena including emission of perfect 1/2〈1 1 1〉-type dislocations and the formation and migration of twin boundaries. It was found that screw dislocation emission is the first deformation mechanism activated at strain rates below 108 s−1. Deformation twins emerge as a deformation mechanism at higher strains, with twins observed to cross grain boundaries as larger strains are reached. At high strain rates atoms are displaced with the characteristic twin vector at a ratio of 3 : 1 (108 s−1) or 4 : 1 (109 s−1) to characteristic dislocation vectors. Fracture is nucleated through a nano-void growth process. Grain boundary sliding does not scale with increasing strain rate. Detailed analysis of nano-scale deformation using these tools enhances our understanding of deformation mechanisms in tantalum. (paper)
The study on the threshold strain of microvoid formation in TRIP steels during tensile deformation
Energy Technology Data Exchange (ETDEWEB)
Wang Wurong; Guo Bimeng; Ji Yurong; He Changwei [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Wei Xicheng, E-mail: wxc1028@staff.shu.edu.cn [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)
2012-06-01
Highlights: Black-Right-Pointing-Pointer The tensile mechanical behaviors of TRIP steels were studied under high rate deformation conditions. Black-Right-Pointing-Pointer The threshold strain of microvoid formation was examined quantitatively. Black-Right-Pointing-Pointer The effects of retained austenite of TRIP on suppressing microvoid formed during tensile process have been discussed. - Abstract: Transformation Induced Plasticity (TRIP) steels exhibit a better combination of strength and ductility properties than conventional high strength low alloy (HSLA) steels, and therefore receive considerable attention in the automotive industry. In this work, the tensile mechanical behaviors of TRIP-aided steels were studied under the condition of the quasi-static and high deformed rates. The deformed specimens were observed by scanning electron microscope (SEM) along the tensile axis. The threshold strain of microvoid formation was examined quantitatively according to the evolution of deformation. The results showed that: the yield and tensile strengths of TRIP steels increase with the strain rate, whereas their elongations decrease. However, the threshold strain for TRIP steels at high strain rate is larger than that at low strain rate. Comparing with the deformed microstructure and microvoids formed in the necking zone of dual phase (DP) steel, the progressive deformation-induced transformation of retained austenite in TRIP steels remarkably increases the threshold strain of microvoid formation and furthermore postpones its growth and coalescence.
Dynamic strain ageing of deformed nitrogen-alloyed AISI 316 stainless steels
Energy Technology Data Exchange (ETDEWEB)
Ehrnsten, U.; Toivonen, A. [Materials and Structural Integrity, VTT Technical Research Centre of Finland, Kemistintie 3, P.O. Box 1704, FIN-02044 VTT (Finland); Ivanchenko, M.; Nevdacha, V.; Yagozinskyy, Y.; Haenninen, H. [Department of Mechanical Engineering, Helsinki University of Technology Puumiehenkuja 3, P.O. Box 4200, FIN-02015 HUT (Finland)
2004-07-01
Intergranular stress corrosion cracking has occurred in BWR environment in non-sensitized, deformed austenitic stainless steel materials. The affecting parameters are so far not fully known, but deformation mechanisms may be decisive. The effect of deformation and nitrogen content on the behaviour of austenitic stainless steels was investigated. The materials were austenitic stainless steels of AISI 316L type with different amounts of nitrogen (0.03 - 0.18%) and they were mechanically deformed 0, 5 and 20%. The investigations are focused on the dynamic strain ageing (DSA) behaviour. A few crack growth rate measurements are performed on nuclear grade AISI 316NG material with different degrees of deformation (0, 5 and 20%). The effects of DSA on mechanical properties of these materials are evaluated based on peaks in ultimate tensile strength and strain hardening coefficient and minimum in ductility in the DSA temperature range. Additionally, internal friction measurements have been performed in the temperature range of -100 to 600 deg. C for determining nitrogen interactions with other alloying elements and dislocations (cold-worked samples). The results show an effect of nitrogen on the stainless steel behaviour, e.g. clear indications of dynamic strain ageing and changes in the internal friction peaks as a function of nitrogen content and amount of deformation. (authors)
Cubic wavefunction deformation of compressed atoms
Portela, Pedro Calvo
2015-01-01
We hypothesize that in a non-metallic crystalline structure under extreme pressures, atomic wavefunctions deform to adopt a reduced rotational symmetry consistent with minimizing interstitial space in the crystal. We exemplify with a simple numeric variational calculation that yields the energy cost of this deformation for Helium to 25%. Balancing this with the free energy gained by tighter packing we obtain the pressures required to effect such deformation. The consequent modification of the structure suggests a decrease in the resistance to tangential stress, and an associated decrease of the crystal's shear modulus. The atomic form factor is also modified. We also compare with neutron matter in the interior of compact stars.
Lunin-Maldacena Deformations With Three Parameters
Catal-Ozer, Aybike
2005-01-01
We examine the solution generating symmetries by which Lunin and Maldacena have generated the gravity duals of beta-deformations of certain field theories. We identify the O(2,2,R) matrix, which acts on the background matrix E=g+B, where g and B are the metric and the B-field of the undeformed background, respectively. This simplifies the calculations and makes some features of the deformed backgrounds more transparent. We also find a new three-parameter deformation of the Sasaki-Einstein man...
Postearthquake deformation analysis of wildlife site
Energy Technology Data Exchange (ETDEWEB)
Gu, W.H. (EBA Engineering, Edmonton, Alberta (Canada)); Morgenstern, N.R.; Robertson, P.K. (Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Civil Engineering)
1994-02-01
Postearthquake deformations of the Wildlife site, Imperial Valley, Calif., following the 1987 Superstition Hills earthquake, have been interpreted by finite-element deformation analyses. The analyses consider the stress redistribution and reconsolidation caused by the development of liquefaction. The stress redistribution analysis was conducted under fully undrained condition to consider the effects of strain-softening behavior of liquefied materials. The reconsolidation analysis was conducted using Biot's theory to consider the effects of dissipation of excess pore-water pressures. The results reveal that the delayed pore-water pressure response and deformation may be due to the redistribution of stresses and pore-water pressures.
2D vector-cyclic deformable templates
DEFF Research Database (Denmark)
Schultz, Nette; Conradsen, Knut
1998-01-01
In this paper the theory of deformable templates is a vector cycle in 2D is described. The deformable template model originated in (Grenander, 1983) and was further investigated in (Grenander et al., 1991). A template vector distribution is induced by parameter distribution from transformation...... matrices applied to the vector cycle. An approximation in the parameter distribution is introduced. The main advantage by using the deformable template model is the ability to simulate a wide range of objects trained by e.g. their biological variations, and thereby improve restoration, segmentation and...
Deformations of GR and BH thermodynamics
Krasnov, Kirill
2016-08-01
In four space–time dimensions General Relativity can be non-trivially deformed. Deformed theories continue to describe two propagating degrees of freedom, as GR. We study Euclidean black hole thermodynamics of these deformations. We use the recently developed formulation that works with {{SO}}(3) connections as well as certain matrices M of auxiliary fields. We show that the black hole entropy is given by one quarter of the horizon area as measured by the Lie algebra valued two-form MF, where F is the connection curvature. This coincides with the horizon area as measured by the metric only for the case of General Relativity.
Monitoring and analysis of rock blocks deformations
Czech Academy of Sciences Publication Activity Database
Cacoń, S.; Kontny, B.; Košťák, Blahoslav
Lisbon: FIG, 2008, s. 1-12. [FIG 13th Symposium on Deformation Measurement and Analysis and the IAG 4th Symposium on Geodesy for Geotechnical and Structural Engineering. Lisbon, Portugal, 12-15 May 2008. Lisbon (PT), 12.05.2008-15.05.2008] R&D Projects: GA ČR GA205/06/1828 Institutional research plan: CEZ:AV0Z30460519 Keywords : rock deformation monitoring * rock deformation model Subject RIV: DC - Siesmology, Volcanology, Earth Structure http://www.fig.net/commission6/lisbon_2008/.
On the thermocapillary motion of deformable droplets
Berejnov, V V
2001-01-01
In studies on Marangoni type motion of particles the surface tension is often approximated as a linear function of temperature. For deformable particles in a linear external temperature gradient far from the reference point this approximation yields a negative surface tension which is physically unrealistic. It is shown that H.Zhou and R.H.Davis J. Colloid Interface Sci., n.181,60,1996 presented calculation where the leading deformable drop moved into a region of negative surface tension. With respect numerical studies the restriction of the migration of two deformable drops is given in terms of the drift time.
Development of DPS (deformable plasma simulation) code
International Nuclear Information System (INIS)
Deformable plasma simulation (DPS) code is developed. DPS code solves a motion of a plasma during feedback control taking into account the deformation of plasma shape. DPS code is developed to study the control system of the plasma position and shape in minor disruptions in which deformation of plasma is not negligible. In this report, the mathematical formulation and the structure of DPS code are presented. As examples of simulations, the results of analysis in the engineering activity of ITER (International Thermonuclear Experimental Reactor) are reported. In appendix, some modified versions of DPS code are presented. (author)
On q-deformed Stirling numbers
Simsek, Yilmaz
2007-01-01
The purpose of this article is to introduce q-deformed Stirling numbers of the first and second kinds. Relations between these numbers, Riemann zeta function and q-Bernoulli numbers of higher order are given. Some relations related to the classical Stirling numbers and Bernoulli numbers of higher order are found. By using derivative operator to the generating function of the q-deformed Stirling numbers of the second kinds, a new function is defined which interpolates the q-deformed Stirling n...
Pritchard, M. E.; Jay, J.; Andrews, B. J.; Cooper, J.; Henderson, S. T.; Delgado, F.; Biggs, J.; Ebmeier, S. K.
2014-12-01
Satellite Interferometric Synthetic Aperture Radar (InSAR) has greatly expanded the number volcanoes that can be monitored for ground deformation - the number of known deforming volcanoes has increased almost five-fold since 1997 (to more than 213 volcanoes in 2014). However, from 1992-2014, there are still gaps in global volcano surveillance and only a fraction of the 1400 subaerial Holocene volcanoes have frequent observations in this time period. Starting in 2014, near global observations of volcano deformation should begin with the Sentinel satellites from the European Space Agency, ALOS-2 from the Japanese Space Agency, and eventually NISAR from the Indian Space Agency and NASA. With more frequent observations, more volcano deformation episodes are sure to be observed, but evaluating the significance of the observed deformation is not always straightforward -- how can we determine if deformation will lead to eruption? To answer this question, an international task force has been formed to create an inventory of volcano deformation events as part of the Global Volcano Model (http://globalvolcanomodel.org/gvm-task-forces/volcano-deformation-database/). We present the first results from our global study focusing on volcanoes that have few or no previous studies. In some cases, there is a lack of SAR data (for example, volcanoes of the South Sandwich Islands). For others, observations either show an absence of deformation or possible deformation that requires more data to be verified. An example of a deforming volcano that has few past studies is Pagan, an island in the Marianas Arc comprised of 2 stratovolcanoes within calderas. Our new InSAR measurements from both the ALOS and Envisat satellites show deformation near the 1981 May VEI 4 lava flow eruption on North Pagan at 2-3 cm/year between 2004-2010. Another example of a newly observed volcano is Karthala volcano in the Comoros. InSAR observations between 2004-2010 span four eruptions, only one of which is
Deformation Behavior of Nanoporous Metals
Energy Technology Data Exchange (ETDEWEB)
Biener, J; Hodge, A M; Hamza, A V
2007-11-28
of free surfaces can no longer be neglected. As the material becomes more and more constraint by the presence of free surfaces, length scale effects on plasticity become more and more important and bulk properties can no longer be used to describe the material properties. Even the elastic properties may be affected as the reduced coordination of surface atoms and the concomitant redistribution of electrons may soften or stiffen the material. If, and to what extend, such length scale effects control the mechanical behavior of nanoporous materials depends strongly on the material and the characteristic length scale associated with its plastic deformation. For example, ductile materials such as metals which deform via dislocation-mediated processes can be expected to exhibit pronounced length scale effects in the sub-micron regime where free surfaces start to constrain efficient dislocation multiplication. In this chapter we will limit our discussion to our own area of expertise which is the mechanical behavior of nanoporous open-cell gold foams as a typical example of nanoporous metal foams. Throughout this chapter we will review our current understanding of the mechanical properties of nanoporous open-cell foams including both experimental and theoretical studies.
Kidder, Steven; Hirth, Greg; Avouac, Jean-Philippe; Behr, Whitney
2016-02-01
Deformation of middle crustal shear zones likely varies with time as a result of the stress build-up and release associated with earthquakes and post-seismic deformation, but the processes involved and their microstructural signature in the rock record are poorly understood. We conducted a series of experiments on quartzite at 900 °C to characterize microstructures associated with changes in stress and strain rate, and to investigate the feasibility of carrying out grain size piezometry in natural rocks that experienced analogous changes. Differential stress (referred to simply as "stress") was varied in two-stage experiments by changing strain rate and by stopping the motor and allowing stress to relax. The two-stage samples preserve a microstructural record that can be interpreted quantitatively in terms of stress history. The microstructure associated with a stress increase is a bimodal distribution of recrystallized grain sizes. The smaller grains associated with the second deformation stage accurately record the stress of the second stage, and the surviving coarse grains remain similar in size to those formed during the earlier stage. The transient microstructure associated with stress decrease is a "partial foam" texture containing a larger concentration of stable 120° triple junctions than occur in samples deformed at a relatively constant strain rate. Our results indicate that microstructures preserved in rocks that experienced relatively simple, two-stage deformation histories can be used to quantitatively assess stress histories. Grain growth rates during deformation are similar to rates observed in previous isostatic growth experiments, supporting theoretical approaches to recrystallized grain size, such as the wattmeter theory (Austin and Evans, 2007), that incorporate static growth rates. From an analysis of the experimental data for quartz recrystallized grain size, we find: 1) Recrystallized grain size quickly reaches a value consistent with
PGE distribution in deformed lherzolites of the Udachnaya kimberlite pipe (Yakutia)
Ilyina, O. V.; Tychkov, N. S.; Agashev, A. M.; Golovin, A. V.; Izokh, A. E.; Kozmenko, O. A.; Pokhilenko, N. P.
2016-04-01
The results of the first study of the PGE distribution in deformed lherzolites of the Udachnaya kimberlite pipe (Yakutia) are presented here. The complex character of evolution of the PGE composition in the Deformed lherzolites is assumed to be the result of silicate metasomatism. At the first stage, growth in the amount of clinopyroxene and garnet in the rock is accompanied by a decrease in the concentration of the compatible PGE (Os, Ir). During the final stage, the rock is enriched with incompatible PGE (Pt, Pd) and Re possible due to precipitation of submicron-sized particles of sulfides in the interstitial space of these mantle rocks.
Microstructure evolution of hot-deformed Nd-Fe-B anisotropic magnets
Energy Technology Data Exchange (ETDEWEB)
Liu, J., E-mail: liu.jun@nims.go.jp; Hono, K. [Elements Strategy Initiative Center for Magnetic Materials, National Institute for Materials Science, Tsukuba 305-0047 (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8577 (Japan); Sepehri-Amin, H.; Ohkubo, T. [Elements Strategy Initiative Center for Magnetic Materials, National Institute for Materials Science, Tsukuba 305-0047 (Japan); Hioki, K.; Hattori, A. [Daido Steel Co. Ltd., Nagoya 457-8545 (Japan)
2014-05-07
The microstructural evolution of hot-deformed Nd-Fe-B magnets in each stage of hot-deformation process was studied using transmission electron microscopy and three dimensional atom probe (3DAP). The anisotropic growth of initially isotropic grains in rapidly solidified alloy occurs by annealing without pressing. 3DAP analyses showed a higher concentration of rare-earth elements in the intergranular phase parallel to the flat surface of platelet shaped Nd{sub 2}Fe{sub 14}B grains compared to that in the intergranular phase at the side of platelets.
Energy Technology Data Exchange (ETDEWEB)
Radhakrishnan, Balasubramaniam [ORNL; Gorti, Sarma B [ORNL
2008-01-01
Thermo-mechanical processing to produce optimum grain structure and texture is key to the successful utilization of commercial aluminum alloys and steels as sheet products. Several modeling techniques have been developed in the past with a reasonably good predictive capability for bulk deformation textures. However, prediction of texture evolution during recrystallization remains very challenging because of uncertainties involved in predicting the mechanisms that lead to nuclei formation and crystallographic orientations of the nuclei, and the uncertainties involved in predicting the grain boundary properties that determine the growth kinetics of the nuclei. We present some of our recent work in modeling the recrystallization textures following hot deformation in polycrystalline BCC and FCC metals.
Large poroelastic deformation of a soft material
MacMinn, Christopher W.; Dufresne, Eric R.; Wettlaufer, John S.
2014-11-01
Flow through a porous material will drive mechanical deformation when the fluid pressure becomes comparable to the stiffness of the solid skeleton. This has applications ranging from hydraulic fracture for recovery of shale gas, where fluid is injected at high pressure, to the mechanics of biological cells and tissues, where the solid skeleton is very soft. The traditional linear theory of poroelasticity captures this fluid-solid coupling by combining Darcy's law with linear elasticity. However, linear elasticity is only volume-conservative to first order in the strain, which can become problematic when damage, plasticity, or extreme softness lead to large deformations. Here, we compare the predictions of linear poroelasticity with those of a large-deformation framework in the context of two model problems. We show that errors in volume conservation are compounded and amplified by coupling with the fluid flow, and can become important even when the deformation is small. We also illustrate these results with a laboratory experiment.
Deformed versus undeformed cat states encoding qubit
International Nuclear Information System (INIS)
We study the possibility of exploiting superpositions of coherent states to encode qubits. A comparison between the use of deformed and undeformed bosonic algebra is made in connection with the amplitude damping errors
Deformed and twisted black holes with NUTs
Krtous, Pavel; Frolov, Valeri P; Kolar, Ivan
2015-01-01
We construct a new class of vacuum black hole solutions whose geometry is deformed and twisted by the presence of NUT charges. The solutions are obtained by `unspinning' the general Kerr-NUT-(A)dS spacetimes, effectively switching off some of their rotation parameters. The resulting geometry has a structure of warped space with the Kerr-like Lorentzian part warped to a Euclidean metric of deformed and/or twisted sphere, with the deformation and twist characterized by the `Euclidean NUT' parameters. In the absence of NUTs, the solution reduces to a well known Kerr-(A)dS black hole with several rotations switched off. New geometries inherit the original symmetry of the Kerr-NUT-(A)dS family, namely, they possess the full Killing tower of hidden and explicit symmetries. As expected, for vanishing NUT, twist, and deformation parameters, the symmetry is further enlarged.
Deformed and twisted black holes with NUTs
Krtouš, Pavel; Kubizňák, David; Frolov, Valeri P.; Kolář, Ivan
2016-06-01
We construct a new class of vacuum black hole solutions whose geometry is deformed and twisted by the presence of NUT charges. The solutions are obtained by ‘unspinning’ the general Kerr-NUT-(A)dS spacetimes, effectively switching off some of their rotation parameters. The resulting geometry has a structure of warped space with the Kerr-like Lorentzian part warped to a Euclidean metric of a deformed and/or twisted sphere, with the deformation and twist characterized by the ‘Euclidean NUT’ parameters. In the absence of NUTs, the solution reduces to a well known Kerr-(A)dS black hole with several rotations switched off. New geometries inherit the original symmetry of the Kerr-NUT-(A)dS family, namely, they possess the full Killing tower of hidden and explicit symmetries. As expected, for vanishing NUT, twist, and deformation parameters, the symmetry is further enlarged.
Modeling tire deformation for power loss calculations
Energy Technology Data Exchange (ETDEWEB)
Whicker, D.; Rohde, S.M.
1981-01-01
A combined thermo-mechanical model for calculating tire power loss has been developed at GMR. This paper presents the techniques for developing the realistic finite element models needed in both the thermal and deformation portions of the combined model. It also describes the techniques used in calculating deformed tire shapes. First, procedures are outlined for automatically generating a finite element discretization of a tire. Then, this discretization, together with information about the properties of tire materials, is used to develop a finite element model of the tire. This model is used in MSC NASTRAN to calculate compliances, i.e., the response of the tire to inflation and to unit loads applied at points on the tire surface. These compliances are then used in an algorithm which calculates the deformed shape of a tire loaded against the pavement surface. Sample results are presented to show the agreement between calculated and measured tire deformation.
Wind sock deformity in rectal atresia
International Nuclear Information System (INIS)
Rectal atresia is a rare anorectal deformity. It usually presents with neonatal obstruction and it is often a complete membrane or severe stenosis. Windsock deformity has not been reported in rectal atresia especially, having been missed for 2 years. A 2-year-old girl reported only a severe constipation despite having a 1.5-cm anal canal in rectal examination with scanty discharge. She underwent loop colostomy and loopogram, which showed a wind sock deformity of rectum with mega colon. The patient underwent abdominoperineal pull-through with good result and follow-up. This is the first case of the wind sock deformity in rectal atresia being reported after 2 years of age. (author)
Deformations of Special Legendrian Submanifolds with Boundary
Lu, Guangcun
2011-01-01
In this article, for a compact special Legendrian submanifold with boundary of contact Calabi-Yau manifolds we study the deformation of it with boundary confined in an appropriately chosen contact submanifold of codimension two which we also a scafford (Definition \\ref{def:2.3}) by analogy with [A.Butsher, Deformations of minimal Lagrangian submanifolds with boundary, Proc. Amer. Math. Soc. 131(2002) 1953-1964]. Our first result shows that it cannot be deformed, and the second claims that deformations of such a special Legendrian submanifold forms a one-dimensional smooth manifold under suitably weaker boundary confinement conditions. They may be viewed as supplements of the boundless case considered by Tomassini and Vezzoni [Contact Calabi-Yau manifolds and special Legendrian submanifolds, Osaka J. Math., 45(2008), 127-147].
Deformation induced martensitic transformation in stainless steels
International Nuclear Information System (INIS)
Deformation induced martensitic transformation was investigated in metastable austenitic stainless steel. This steel can present a microstructure of austenite (γ), α' martensite and non magnetic ε martensite. Uni-axial tensile test was used for loading at different temperatures below room temperature (from -120 to 20 deg. C). During the deformation the transformation takes place at certain places in an anisotropic way and texture also develops. Quantitative phase analysis was done by X-ray diffraction (XRD) and magnetic methods while the texture was described by X-ray diffraction using a special inverse pole figure. The quantitative phase analysis has shown that the formation of α' and ε martensite from austenite is the function of deformation rate, and deformation temperature. The transformation of the textured austenite takes place in an anisotropic way and a well defined crystallographic relationship between the parent and α' martensite phase has been measured
Driver ASICs for Advanced Deformable Mirrors Project
National Aeronautics and Space Administration — The program leverages on our extensive expertise in developing high-performance driver ASICs for deformable mirror systems and seeks to expand the capacities of the...
Driver ASICs for Advanced Deformable Mirrors Project
National Aeronautics and Space Administration — The overall goal of the SBIR program is to develop a new Application Specified Integrated Circuit (ASIC) driver to be used in driver electronics of a deformable...
Deformation stages of technical aluminum at reverse
Vaulina, O. Yu; Durnovtseva, A. N.; Shvagrukova, E. V.
2016-02-01
Durability and reliability of machines and mechanisms are determined, mainly, by their fatigue resistance as far as, in the most cases, variable load impacts on machine components. Accordingly, the problem of fatigue failure is extremely topical, still. Its complexity is connected with a wide range of factors. First of all, at cyclic load the compatibility relations of a material surface layer, which is loaded over the yield point and the elastic-loaded substrate layer, play a very important role. This fact determines involvement into plastic flow and failure of all the scale hierarchy of deformation structural levels. Reverse loading under the condition of the elastic-loaded substrate layer causes strong localization of plastic deformation in the surface layers. In the deformation localization areas the material reaches its limit state, when fatigue cracks arise and expand. The paper presents the mechanisms of fatigue deformation for technical aluminum at various fatigue stages.
High Resolution Silicon Deformable Mirrors Project
National Aeronautics and Space Administration — This proposal describes a plan to build a prototype small stroke, high precision deformable mirror suitable for space-based operation in systems for high-resolution...
High Resolution Silicon Deformable Mirrors Project
National Aeronautics and Space Administration — In this proposal we describe a plan to build a deformable mirror suitable for space-based operation in systems for high-resolution imaging. The prototype DM will be...
Wind sock deformity in rectal atresia
Directory of Open Access Journals (Sweden)
Hosseini Seyed
2009-01-01
Full Text Available Rectal atresia is a rare anorectal deformity. It usually presents with neonatal obstruction and it is often a complete membrane or severe stenosis. Windsock deformity has not been reported in rectal atresia especially, having been missed for 2 years. A 2-year-old girl reported only a severe constipation despite having a 1.5-cm anal canal in rectal examination with scanty discharge. She underwent loop colostomy and loopogram, which showed a wind sock deformity of rectum with mega colon. The patient underwent abdominoperineal pull-through with good result and follow-up. This is the first case of the wind sock deformity in rectal atresia being reported after 2 years of age.
Noncommutative principal bundles through twist deformation
Aschieri, Paolo; Pagani, Chiara; Schenkel, Alexander
2016-01-01
We construct noncommutative principal bundles deforming principal bundles with a Drinfeld twist (2-cocycle). If the twist is associated with the structure group then we have a deformation of the fibers. If the twist is associated with the automorphism group of the principal bundle, then we obtain noncommutative deformations of the base space as well. Combining the two twist deformations we obtain noncommutative principal bundles with both noncommutative fibers and base space. More in general, the natural isomorphisms proving the equivalence of a closed monoidal category of modules and its twist related one are used to obtain new Hopf-Galois extensions as twists of Hopf-Galois extensions. A sheaf approach is also considered, and examples presented.
Directory of Open Access Journals (Sweden)
Ermis Hayri
2003-01-01
Full Text Available Abstract Background Wolf-Hirschhorn syndrome is caused by distal deletion of the short arm of chromosome 4 (4p-. We report a case in which intrauterine growth restriction, hypospadias and foot deformity were detected by prenatal ultrasound examination at 29 weeks of gestation. Case Presentation A 31-year-old gravida 2 partus 1 woman was referred at 29 weeks' gestation with suspicion of intrauterine growth restriction. Sonographic examination revealed deformity of the right lower limb and undescended testes with an irregular distal penis. A cordocentesis was performed and chromosome analysis revealed a 46,XY,del(4(p14 karyotype. Conclusion The prenatal detection of intrauterine growth restriction, hypospadias and foot deformity should lead doctors to suspect the presence of Wolf-Hirschhorn syndrome.
Deformation processes in polycrystalline aggregates of gypsum
S Meer
1995-01-01
On the basis of both field and laboratory studies it is well established that polycrystalline gypsum is one of the weakest and most ductile rock materials found in the Earth's crust (e.g. Heard & Rubey, 1966; Murrell & Ismail, 1976; Baumann, 1985; Jordan, 1988; 1991; 1994). The deformation and densification behaviour of polycrystalline gypsum aggregates, and the underlying microphysical processes which control deformation, thus form a subject of considerable interest in a number of areas of s...
Deformation of Outer Representations of Galois Group
Rastegar, Arash
2004-01-01
To a hyperbolic smooth curve defined over a number-field one naturally associates an "anabelian" representation of the absolute Galois group of the base field landing in outer automorphism group of the algebraic fundamental group. In this paper, we introduce several deformation problems for Lie-algebra versions of the above representation and show that, this way we get a richer structure than those coming from deformations of "abelian" Galois representations induced by the Tate module of asso...
Soft deformable self-propelled particles
Menzel, Andreas M.; Ohta, Takao
2012-01-01
In this work we investigate the collective behavior of self-propelled particles that deform due to local pairwise interactions. We demonstrate that this deformation alone can induce alignment of the velocity vectors. The onset of collective motion is analyzed. Applying a Gaussian-core repulsion between the particles, we find a transition to disordered non-collective motion under compression. We here explain that this reflects the reentrant fluid behavior of the general Gaussian-core model now...
Deformation in locally convex topological linear spaces
Institute of Scientific and Technical Information of China (English)
DING; Yanheng
2004-01-01
We are concerned with a deformation theory in locally convex topological linear spaces. A special "nice" partition of unity is given. This enables us to construct certain vector fields which are locally Lipschitz continuous with respect to the locally convex topology. The existence, uniqueness and continuous dependence of flows associated to the vector fields are established. Deformations related to strongly indefinite functionals are then obtained. Finally, as applications, we prove some abstract critical point theorems.
Combinatorial Deformations of Algebras: Twisting and Perturbations
Duchamp, Gérard Henry Edmond; Tollu, Christophe; Penson, K. A.; Koshevoy, Gleb
2010-01-01
The framework used to prove the multiplicative law deformation of the algebra of Feynman-Bender diagrams is a \\textit{twisted shifted dual law} (in fact, twice). We give here a clear interpretation of its two parameters. The crossing parameter is a deformation of the tensor structure whereas the superposition parameters is a perturbation of the shuffle coproduct of Hoffman type which, in turn, can be interpreted as the diagonal restriction of a superproduct. Here, we systematically detail the...
Evaluating permanent deformation in asphalt rubber mixtures
Fontes, Liseane P. T. L.; Trichês, Glicério; Pais, Jorge C.; Pereira, Paulo A. A.
2009-01-01
Permanent deformation or rutting, one of the most important distresses inflexible pavements, has long been a problem in asphalt mixtures. Throughout the years, researchers have used different test methods lo estimate the performance of asphalt mixtures in relation to rutting. One of the alternatives to reduce permanent deformation in asphalt pavement layers is through the use of mixtures produced with asphalt rubber This work aims at comparing the performance of a conventional dense graded mi...
International Nuclear Information System (INIS)
A scheme of q-deformation of nonlinear maps is introduced. As a specific example, a q-deformation procedure related to the Tsallis q-exponential function is applied to the logistic map. Compared to the canonical logistic map, the resulting family of q-logistic maps is shown to have a wider spectrum of interesting behaviours, including the co-existence of attractors-a phenomenon rare in one-dimensional maps
Strengthening of HSLA steels by cool deformation
a Fatehi; Calvo Muñoz, Jessica; Elwazri, A. M.; Yue, S
2010-01-01
In microalloyed steels, the refinement of ferrite grains together with a controlled amount of precipitation has key roles in the mechanical properties improvement. Applying small amounts of deformation, at very low hot working temperatures (i.e. coiling temperature), in the ferrite region (i.e. cool deformation) has an appreciable strengthening effect via controlling the final microstructure of the steel. One of the microstructural effects is thought to be the much finer and more uniformly...
Large deformation dynamic bending of composite beams
Derian, Edward J.
1985-01-01
The large deformation response of composite beams subjected to a dynamic axial load was studied. The beams were loaded with a moderate amount of eccentricity to promote bending. The study was primarily experimental but some finite element results were obtained. Both the deformation and the failure of the beams were of interest. The static response of the beams was also studied in order to determine the difference between the static and dynamic failure. Twelve different la...
Deformed Bosons: Combinatorics of Normal Ordering
Blasiak, P; Penson, K A; Solomon, A I
2004-01-01
We solve the normal ordering problem for (A* A)^n where A* (resp. A) are one mode deformed bosonic creation (resp. annihilation) operators satisfying [A,A*]=[N+1]-[N]. The solution generalizes results known for canonical and q-bosons. It involves combinatorial polynomials in the number operator N for which the generating functions and explicit expressions are found. Simple deformations provide examples of the method.
Maps between Deformed and Ordinary Gauge Fields
Mesref, L.
2005-01-01
In this paper, we introduce a map between the q-deformed gauge fields defined on the GL$_{q}(N) $-covariant quantum hyperplane and the ordinary gauge fields. Perturbative analysis of the q-deformed QED at the classical level is presented and gauge fixing $\\grave{a} $ la BRST is discussed. An other star product defined on the hybrid $(q,h) $% -plane is explicitly constructed .
Infinitesimal Automorphisms and Deformations of Parabolic Geometries
Cap, Andreas
2005-01-01
We show that infinitesimal automorphisms and infinitesimal deformations of parabolic geometries can be nicely described in terms of the twisted de-Rham sequence associated to a certain linear connection on the adjoint tractor bundle. For regular normal geometries, this description can be related to the underlying geometric structure using the machinery of BGG sequences. In the locally flat case, this leads to a deformation complex, which generalizes the is well know complex for locally confor...
Intermittent dislocation flow in viscoplastic deformation
Miguel, M. -Carmen; Vespignani, Alessandro; Zapperi, Stefano; Weiss, Jerome; Grasso, Jean-Robert
2001-01-01
The viscoplastic deformation (creep) of crystalline materials under constant stress involves the motion of a large number of interacting dislocations. Analytical methods and sophisticated `dislocation-dynamics' simulations have proved very effective in the study of dislocation patterning, and have led to macroscopic constitutive laws of plastic deformation. Yet, a statistical analysis of the dynamics of an assembly of interacting dislocations has not hitherto been performed. Here we report ac...
Elasticity, viscosity, and deformation of orbital fat
Schoemaker, Ivo; Hoefnagel, Pepijn; Mastenbroek, Tom; Kolff, Cornelis; Schutte, Sander; van der Helm, Frans; Picken, Stephen; Gerritsen, Anton; Wielopolski, Piotr; Spekreijse, Henk; Simonsz, Huib
2006-01-01
textabstractPURPOSE. For development of a finite element analysis model of orbital mechanics, it was necessary to determine the material properties of orbital fat and its degree of deformation in eye rotation. METHODS. Elasticity and viscosity of orbital fat of eight orbits of four calves and two orbits of one rhesus monkey were measured with a parallel-plate rheometer. The degree of deformation of orbital fat was studied in two human subjects by magnetic resonance imaging (MRI) through the o...
Layered Structures in Deformed Metals and Alloys
DEFF Research Database (Denmark)
Hansen, Niels; Zhang, Xiaodan; Huang, Xiaoxu
2014-01-01
Layered structures characterize metals and alloys deformed to high strain. The morphology is typical lamellar or fibrous and the interlamellar spacing can span several length scales down to the nanometer dimension. The layered structures can be observed in bulk or in surface regions, which is shown......-structure relationships. Finally, the results will be discussed based on universal principles for the evolution of microstructure and properties during plastic deformation of metals and alloys from low to high strain....
Investigation of Plastic Deformation Considering Nanoscale Effects
Directory of Open Access Journals (Sweden)
Yushchenko O.V.
2015-08-01
Full Text Available The self-consistent theory of plastic deformation in solid was considered within the framework of the presence of the nanoscale defects ensemble. The synergetic equations describing the self-organization of nanoscale defects were analyzed. An effective potential that distinguish plastic and solid states was obtained. For the plastic deformation waves the dispersion law depending on the diffusion coefficient of the defects was considered.
Thermal elastic deformations of the planet Mercury.
Liu, H.-S.
1972-01-01
The variation in solar heating due to the resonance rotation of Mercury produces periodic elastic deformations on the surface of the planet. The thermal stress and strain fields under Mercury's surface are calculated after certain simplifications. It is found that deformations penetrate to a greater depth than the variation of solar heating, and that the thermal strain on the surface of the planet pulsates with an amplitude of .004 and a period of 176 days.
Energy Technology Data Exchange (ETDEWEB)
Desbat, L. [Universite Joseph Fourier, UMR CNRS 5525, 38 - Grenoble (France); Roux, S. [Universite Joseph Fourier, TIMC-IMAG, In3S, Faculte de Medecine, 38 - Grenoble (France)]|[CEA Grenoble, Lab. d' Electronique et de Technologie de l' Informatique (LETI), 38 (France); Grangeat, P. [CEA Grenoble, Lab. d' Electronique et de Technologie de l' Informatique (LETI), 38 (France)
2005-07-01
This work is a contribution to the compensation of motion in tomography. New classes of deformation are proposed, that compensates analytically by an algorithm of a F.B.P. type reconstruction. This work makes a generalisation of the known results for affine deformations, in parallel geometry and fan-beam, to deformation classes of infinite dimension able to include strong non linearities. (N.C.)
Membranotropic photobiomodulation on red blood cell deformability
Luo, Gang-Yue; Zhao, Yan-Ping; Liu, Timon C.; Liu, Song-Hao
2007-05-01
To assess modulation of laser on erythrocyte permeability and deformability via cell morphology changes, healthy human echinocytes with shrinking size and high plasmic viscosity due to cellular dehydration were treated with 1 mW, 2 mW, 3 mW, and 5 mW laser power exposure respectively. Image analyzing system on single intact erythrocyte was applied for measuring comprehensive cell morphological parameters (surface area, external membrane perimeter, circle index and elongation index) that were determined by the modulation of erythrocyte water permeability and deformability to detect relationship between erythrocyte water permeability alteration and deformability. Our preliminary experiment showed that exposure under light dose of 5 mW for 5 min could induce more active erythrocyte swelling and deformation. water channel aquaporin-1(AQP-1) was inhibited by the incubation of HgCl II in the presence and absence of 5 mW laser irradiation. The result suggested that osmotic water permeability is a primary factor in the procedure of erythrocyte deformability. In addition, no modulation of laser(5mW) on erythrocyte deformability had been found when the echinocytes were cultured with GDP-β-S (G protein inhibitor).
Bialgebra cohomology, deformations, and quantum groups.
Gerstenhaber, M; Schack, S D
1990-01-01
We introduce cohomology and deformation theories for a bialgebra A (over a commutative unital ring k) such that the second cohomology group is the space of infinitesimal deformations. Our theory gives a natural identification between the underlying k-modules of the original and the deformed bialgebra. Certain explicit deformation formulas are given for the construction of quantum groups--i.e., Hopf algebras that are neither commutative nor cocommutative (whether or not they arise from quantum Yang-Baxter operators). These formulas yield, in particular, all GLq(n) and SLq(n) as deformations of GL(n) and SL(n). Using a Hodge decomposition of the underlying cochain complex, we compute our cohomology for GL(n). With this, we show that every deformation of GL(n) is equivalent to one in which the comultiplication is unchanged, not merely on elements of degree one but on all elements (settling in the strongest way a decade-old conjecture) and in which the quantum determinant, as an element of the underlying k-module, is identical with the usual one. PMID:11607053
Structure and properties of copper deformed by severe plastic deformation methods
Directory of Open Access Journals (Sweden)
M. Richert
2011-01-01
Full Text Available Purpose: The main object of this study is to establish the influence of severe plastic deformation on the microstructure evolution and properties of polycrystalline copper Cu99.99.Design/methodology/approach: Polycrystalline copper Cu99.99 was deformed by cyclic extrusion compression (CEC, equal channel angular pressing (ECAP and hydrostatic extrusion (HE. Additionally the combination of these methods were applying to the sample deformations. The microstructure and properties of samples after different kinds of severe mode of deformations (SPD were examined and compared as well as their properties. The microstructure was investigated by optical (MO and transmission electron microscopy (TEM. The microhardness was measured by PMT3 microhardness tester.Findings: It was found that increase of deformation diminishing the microstructure and leads to the increase of microhardness of samples.Practical implications: The results may be utilized for determination of a relation between microstructure and properties of the copper deformed in the severe plastic deformation process.Originality/value: The results contribute to evaluation properties of the polycrystalline copper deformed to very large strains exerting the typical range of deformations.
Dealing with difficult deformations: Construction of a knowledge-based deformation atlas
DEFF Research Database (Denmark)
Thorup, Signe Strann; Darvann, T.A.; Hermann, N.V.;
2010-01-01
(atlases) for the pre- and post-surgical populations, respectively, were automatically constructed by non-rigid registration. An expert placed corresponding landmarks in the cleft area in the two atlases; this provided prior information used to build a knowledge-based deformation atlas. We model the change...... from before to after lip closure in infants with UCLP. The purpose of the present work was to show that use of prior information about typical deformations due to lip closure, through the construction of a knowledge-based atlas of deformations, could overcome the problem. Initially, mean volumes...... simple way of dealing with complex morphological changes using knowledge of typical deformations....
Constrained Deformable-Layer Tomography
Zhou, H.
2006-12-01
The improvement on traveltime tomography depends on improving data coverage and tomographic methodology. The data coverage depends on the spatial distribution of sources and stations, as well as the extent of lateral velocity variation that may alter the raypaths locally. A reliable tomographic image requires large enough ray hit count and wide enough angular range between traversing rays over the targeted anomalies. Recent years have witnessed the advancement of traveltime tomography in two aspects. One is the use of finite frequency kernels, and the other is the improvement on model parameterization, particularly that allows the use of a priori constraints. A new way of model parameterization is the deformable-layer tomography (DLT), which directly inverts for the geometry of velocity interfaces by varying the depths of grid points to achieve a best traveltime fit. In contrast, conventional grid or cell tomography seeks to determine velocity values of a mesh of fixed-in-space grids or cells. In this study, the DLT is used to map crustal P-wave velocities with first arrival data from local earthquakes and two LARSE active surveys in southern California. The DLT solutions along three profiles are constrained using known depth ranges of the Moho discontinuity at 21 sites from a previous receiver function study. The DLT solutions are generally well resolved according to restoration resolution tests. The patterns of 2D DLT models of different profiles match well at their intersection locations. In comparison with existing 3D cell tomography models in southern California, the new DLT models significantly improve the data fitness. In comparison with the multi-scale cell tomography conducted for the same data, while the data fitting levels of the DLT and the multi-scale cell tomography models are compatible, the DLT provides much higher vertical resolution and more realistic description of the undulation of velocity discontinuities. The constraints on the Moho depth
Institute of Scientific and Technical Information of China (English)
2008-01-01
There exists an interaction between microstructural evolution and deformation behavior in high temperature deformation of titanium alloys. And the microstruc- ture of titanium alloys is very sensitive to the process parameters of plastic de- formation process. In this paper, on the basis of plastic deformation mechanism of metals and alloys, a microstructural model including dislocation density rate equa- tion and grain growth rate equation is established with the dislocation density rate being an internal state variable. Applying the model to the high temperature de- formation process of Ti60 titanium alloy, the average relative errors of grain sizes between the experiments and the predictions are 9.47% for sampled data, and 13.01% for non-sampled data.
Deformities and injuries of the ankle joint in children and adolescents
International Nuclear Information System (INIS)
Knowledge of the normal development of the ankle joint is mandatory to understand the mechanism of injuries in children and adolescents. Some fractures (juvenile Tillaux's or two-fragment triplane fracture) occur only within a particular period of growth, which is determined by the degree of epiphyseal fusion. Tarsal coalitions are the deformities seen most frequently. Special radiographic techniques must be applied for the diagnosis. Ball and socket joint, tibiotalar slant and Trevor's disease are rare deformities, each of which is associated with a pathognomonic radiographic pattern. Some typical joint deformities may be seen in patients with neuromuscular disease. This has to be considered when nothing else is found in the clincial history. (orig.)
Tschopp, H M
1988-01-01
The typical nose deformity after cleft-lip repair still represents great challenge for the plastic surgeon in this field. Many methods have been designed in attempts to correct the deformity, either during primary closure of the lip or as a secondary procedure when growth of the nose is complete. In this paper the author's own technique of secondary rhinoseptoplasty in cleft-lip patients is presented. The different cartilaginous and osseous structures are approached through a transcolumellar incision and the skin of the nose completely reflected upwards. This so-called "open sky view" gives a total perspective on the entire pathology of the cleft-lip nose deformity and makes it possible to correct it accordingly. Emphasis is put on some important surgical manoeuvers. Recent results are presented and the pros and cons of this procedure discussed. PMID:3187450
The Differential Equation Algorithm for General Deformed Swept Volumes
Institute of Scientific and Technical Information of China (English)
汪国平; 华宣积; 孙家广
2000-01-01
The differential equation approach for characterizing swept volume boundaries is extended to include objects experiencing deformation. For deformed swept volume, it is found that the structure and algorithm of sweep-envelope differential equation (SEDE) are similar between the deformed and the rigid swept volumes. The efficiency of SEDE approach for deformed swept volume is proved with an example.
The Skin Deformation of a 3D Virtual Human
Institute of Scientific and Technical Information of China (English)
Xiao-Jing Zhou; Zheng-Xu Zhao
2009-01-01
This paper presents a skin deformation algorithm for creating 3D characters or virtual human models. The algorithm can be applied to rigid deformation, joint dependent localized deformation, skeleton driven deformation, cross contour deformation, and free-form deformation (FFD). These deformations are computed and demonstrated with examples and the algorithm is applied to overcome the difficulties in mechanically simulating the motion of the human body by club-shape models. The techniques described in this article enables the reconstruction of dynamic human models that can be used in defining and representing the geometrical and kinematical characteristics of human motion.
Hot deformation in nanocrystalline Nd-Fe-B backward extruded rings
Institute of Scientific and Technical Information of China (English)
Li An-Hua; Zhao Rui; Lai Bin; Wang Hui-Jie; Zhu Ming-Gang; Li Wei
2011-01-01
Radially oriented Nd-Fe-B rings are prepared by backward extrusion of fine grained melt-spun powder.Meltspun powder with the nominal composition of Nd30.sFebal.Co6.0Ga0.6Al0.2B0.9 (wt％) is used as starting material.The effects of process variables,such as deformation temperature (Td),strain rate (ε) and height reduction (Ah％),on the magnetic properties of the rings are investigated.A scanning electron microscope (SEM) equipped with an energy spectrum device is used to study the metallograph and microfracture of the extruded rings.The Br and (BH)max reach the optimum values at Td =800 ℃,ε =0.01 mm/s,and Ah％ =70％.It is found by SEM observations that the particle boundaries,which seemingly correspond to the interfaces of the starting melt-spun powders,emerge after the corrosion of metallography specimens.This is helpful for studying the effects of powder-powder interface on the local deformation and deformation homogeneity in the rings.For different spatial positions of the extruded rings,there are characteristic metallographies and microfractures.The upper end of the rings has the least deformation and worst texture,and therefore the worst magnetic properties.The magnetic properties in the radial direction increase slightly along the axis from the bottom to the middle,then steeply decrease at the upper end of the ring.The deformation and the formation-of-texturing processes are discussed.The deformation and the texturing formation of melt-spun Nd-Fe-B alloys probably involve grain boundary sliding and grain rotation,the solution-precipitation process and preferential growth of Nd2Fe14B nanograins along the easy growth a-axis.
Multiphase Image Segmentation Using the Deformable Simplicial Complex Method
DEFF Research Database (Denmark)
Dahl, Vedrana Andersen; Christiansen, Asger Nyman; Bærentzen, Jakob Andreas
2014-01-01
The deformable simplicial complex method is a generic method for tracking deformable interfaces. It provides explicit interface representation, topological adaptivity, and multiphase support. As such, the deformable simplicial complex method can readily be used for representing active contours in...... image segmentation based on deformable models. We show the benefits of using the deformable simplicial complex method for image segmentation by segmenting an image into a known number of segments characterized by distinct mean pixel intensities....
Analysis of Ground Deformations Induced by Tunnel Excavation
Directory of Open Access Journals (Sweden)
Mingli Huang
2012-08-01
Full Text Available In this study, we analyzing the ground deformation response in water-bearing sandstone ground caused by tunnel excavation. Moreover, based on the field monitoring data of Xiang-an subaqueous tunnel in Xiamen, taking a deep research on ground deformations caused by large cross section tunnel excavation. From our research results, during tunnel excavation surface settlement and extensometer settlement may be divided into four stages: slight deformation stage, rapid deformation stage, stable stage and slow deformation stage.
Analysis on Large Deformation Compensation Method for Grinding Machine
Wang Ya-jie; Huang Yun; Zhang Die; Zhu Deng-wei
2013-01-01
The positioning accuracy of computer numerical control machines tools and manufacturing systems is affected by structural deformations, especially for large sized systems. Structural deformations of the machine body are difficult to model and to predict. Researchs for the direct measurement of the amount of deformation and its compensation are farly limited in domestic and overseas,not involved to calculate the amount of deformation compensation. A new method to compensate large deformation c...
Wobbling excitations in strongly deformed Hf nuclei?
International Nuclear Information System (INIS)
Two Gammasphere experiments have been performed in order to establish the possible triaxial nature of strongly deformed (SD) bands in 174Hf. A lifetime measurement, using the Doppler-shift attenuation method, confirmed the large deformation of the four previously observed bands in this nucleus with transition quadrupole moments ranging from 12.6 to 13.8 b. These values are significantly larger than those predicted for triaxial minima by ultimate cranker (UC) calculations. A thin-target, high-statistics experiment was also carried out to search for linking transitions between the SD bands. No such transitions, which represent an experimental signature for wobbling modes, were observed. Four additional SD bands were found in 174Hf together with a single SD band in 173Hf. These results indicate that the strongly deformed sequences of N∼102 Hf isotopes behave differently than the triaxial strongly deformed (TSD) bands found in Lu nuclei near N=92. The interpretation of these bands in terms of possible stable triaxial deformation is confronted with the experimental findings and UC predictions
PT-symmetrically deformed shock waves
Cavaglia, Andrea
2012-01-01
We investigate for a large class of nonlinear wave equations, which allow for shock wave formations, how these solutions behave when they are PT-symmetrically deformed. For real solutions we find that they are transformed into peaked solutions with a discontinuity in the first derivative instead. The systems we investigate include the PT-symmetrically deformed inviscid Burgers equation recently studied by Bender and Feinberg, for which we show that it does not develop any shocks, but peaks instead. In this case we exploit the rare fact that the PT-deformation can be provided by an explicit map found by Curtright and Fairlie together with the property that the undeformed equation can be solved by the method of characteristics. We generalise the map and observe this type of behaviour for all integer values of the deformation parameter epsilon. The peaks are formed as a result of mapping the multi-valued self-avoiding shock profile to a multi-valued self-crossing function by means of the PT-deformation. For some...
Deformation mechanisms during hot working of titanium
International Nuclear Information System (INIS)
Computer models of metal flow and texture evolution during hot working require accurate descriptions of deformation mechanisms and constitutive behavior. Such descriptions for titanium alloys can be very complex because of the variety of slip systems in the hexagonal (alpha) phase, let alone the complications associated with the deformation of two-phase (alpha/beta) microstructures in commercial alloys. Methods to elucidate the deformation behavior of unalloyed alpha titanium and two-phase Ti-6Al-4V will be described. First, the analysis of the hot deformation of heavily textured bar and plate materials will be described. In these instances, the anisotropy in flow stress and in sample deformation pattern have been used in conjunction with a crystal plasticity code to deduce the relative values of the critical resolved shear stresses for basal , prism , and pyramidal slip. Analysis of the flow curves has also provided insight into the micromechanism of flow softening in two-phase alloys with colony-alpha microstructures. To complement this work, an x-ray line broadening technique was developed to deduce the relative slip activity at large strains in unalloyed titanium and Ti-6Al-4V. These measurements also provided estimates of the dislocation density as a function of temperature and the competition between slip and twinning at cold-working temperatures
A Refined Shear Deformation Plate Theory
Liu, Yucheng
2011-04-01
An improved higher-order shear deformation theory of plates is presented in this paper. The theory is developed from the transverse shear deformation theory presented by Ambartsumian [11]. The present plate theory contains kinematics of higher-order displacement field of plates, a system of higher-order differential equilibrium equations in terms of the three generalized displacements of bending plates, and a system of boundary conditions at each edge of plate boundaries. The present shear deformation theory of plates is validated by applying it to solve torsional plates and simply supported plates. The obtained solutions using the present theory are compared with the solutions of other shear-deformation theories. A good agreement is achieved through these comparisons and the advantages of the present theory are clearly verified. The shear deformation plate theory presented here can be applied to the analysis of laminated composite plates to better predict their dynamic and static behaviors. The proposed theory should also be supplemented to the theory of finite element analysis for developing new shell elements.
Survey of Reflection-Asymmetric Nuclear Deformations
Olsen, Erik; Birge, Noah; Erler, Jochen; Nazarewicz, Witek; Perhac, Alex; Schunck, Nicolas; Stoitsov, Mario; Nuclei Collaboration
2015-10-01
Due to spontaneous symmetry breaking it is possible for a nucleus to have a deformed shape in its ground state. It is theorized that atoms whose nuclei have reflection-asymmetric or pear-like deformations could have non-zero electric dipole moments (EDMs). Such a trait would be evidence of CP-violation, a feature that goes beyond the Standard Model of Physics. It is the purpose of this project to predict which nuclei exhibit a reflection-asymmetric deformation and which of those would be the best candidates for an EDM measuring experiment. Using nuclear Density Functional Theory along with the new computer code AxialHFB and massively parallel computing we calculated ground state nuclear properties for thousands of even-even nuclei across the nuclear chart: from light to superheavy and from stable to short-lived systems. Six different Energy Density Functionals (EDFs) were used to assess systematic errors in our calculations. Overall, 140 even-even nuclei (near and among the lantanides and actinides and in the superheavy region near N = 184) were predicted by all 6 EDFs to have a pear-like deformation. The case of 112Xe also proved curious as it was predicted by 5 EDFs to have a pear-like deformation despite its proximity to the two-proton drip line. Deceased.
Variation of martensite lath width and precipitate size during creep deformation in a 10Cr-Mo steel
International Nuclear Information System (INIS)
The relationship between creep deformation and microstructural changes in martensitic 10Cr-MoW steel has been studied. Transmission electron microscopy and image analyser were used to determine the variation of precipitates and martensite lath width size during creep deformation and aging. As precipitates are coarsened during creep deformation, dislocations become easy to move and the recovery proceeds rapidly. This leads to the growth of lath width. The average size of precipitates was linearly increased with creep time. On the other hand the growth rate of lath width is constant until tertiary creep, but the growth of lath width is accelerated during tertiary creep. It has been concluded that the growth behavior of lath width are consistent with creep deformation. Because the growth of lath width is controlled by the coarsening of precipitates it is important to form more stable precipitates in creep condition for improvement of creep properties of martensitie steel. Microstructure of martensitic steel is thermally very stable, so the size of precipitates and martensite lath width are hardly changed during aging
Directory of Open Access Journals (Sweden)
Masafumi Noda
2011-01-01
Full Text Available Magnesium alloys can be used for reducing the weight of various structural products, because of their high specific strength. They have attracted considerable attention as materials with a reduced environmental load, since they help to save both resources and energy. In order to use Mg alloys for manufacturing vehicles, it is important to investigate the deformation mechanism and transition point for optimizing the material and vehicle design. In this study, we investigated the transition of the deformation mechanism during the high-temperature uniaxial tensile deformation of the AZ31 Mg alloy. At a test temperature of 523 K and an initial strain rate of 3×10−3 s-1, the AZ31 Mg alloy (mean grain size: ~5 μm exhibited stable deformation behavior and the deformation mechanism changed to one dominated by grain boundary sliding.
A New Simple Model for the Mushrooming Deformation of Projectile Impacting on A Deformable Target
Institute of Scientific and Technical Information of China (English)
Zhang Xiaoqing; Yang Guitong
2004-01-01
Based on Taylor's model and Hawkyard's model, a new simple model for the mushrooming deformation of projectile impacting on a deformable target is installed considering the penetration of the projectile to the deformable target. In the model, the following time-dependent variables are involved in: the extent and the particle velocity in the rigid zone; the extent, the cross-section area and the particle velocity in plastic zone; the velocity and depth of the penetrating of projectile to the target. Solving the set of equations, analytic solution is given. The profiles of deformed projectile and shape parameters for different initial impact velocities are shown. The duration time of deformation increases with increasing the impact velocity. The analytical results by using this model are coincident with experimental result.
Invasion Patterns During Two-phase Flow In Deformable Porous Media
Eriksen, Fredrik K.; Toussaint, Renaud; Jørgen Måløy, Knut; Grude Flekkøy, Eirik
2016-04-01
We will present our experimental study of the viscous fingering and fracturing patterns that occur when air at constant overpressure invades a circular Hele-Shaw cell containing a liquid-saturated deformable porous medium [1] - i.e. during the flow of two non-miscible fluids in a confined granular medium at high enough rate to deform it. The resulting patterns are characterized in terms of growth rate, average finger thickness as function of radius and time, and fractal properties. Based on experiments with various injection pressures, we identify and compare typical pattern characteristics when there is no deformation, compaction, and/or decompaction of the porous medium. This is achieved by preparing monolayers of glass beads in cells with various boundary conditions, ranging from a rigid disordered porous medium to a deformable granular medium with either a semi-permeable or a free outer boundary. We show that the patterns formed have characteristic features depending on the boundary conditions. For example, the average finger thickness is found to be constant with radius in the non-deformable system, while in the deformable ones there is a larger initial thickness decreasing to the non-deformable value. Then, depending on whether the outer boundary is semi-permeable or free there is a further decrease or increase in the average finger thickness. When estimated from the flow patterns, the box-counting fractal dimensions Db= 1.59±0.06 are not found to change significantly with boundary conditions, but by using a method to locally estimate fractal dimensions, we see a transition in behavior with radius for patterns in deformable systems; In the deformable system with a free boundary, it seems to be a transition in universality class as the local fractal dimensions decrease towards the outer rim, where fingers are opening up like fractures in a paste. In addition, we show a collapse of mass N plotted as function of radius r for the patterns at different snapshots
Guo, Quan; Duffy, Simon P; Matthews, Kerryn; Deng, Xiaoyan; Santoso, Aline T; Islamzada, Emel; Ma, Hongshen
2016-02-21
The loss of red blood cell (RBC) deformability is part of the pathology of many diseases. In malaria caused by Plasmodium falciparum infection, metabolism of hemoglobin by the parasite results in progressive reduction in RBC deformability that is directly correlated with the growth and development of the parasite. The ability to sort RBCs based on deformability therefore provides a means to isolate pathological cells and to study biochemical events associated with disease progression. Existing methods have not been able to sort RBCs based on deformability or to effectively enrich for P. falciparum infected RBCs at clinically relevant concentrations. Here, we develop a method to sort RBCs based on deformability and demonstrate the ability to enrich the concentration of ring-stage P. falciparum infected RBCs (Pf-iRBCs) by >100× from clinically relevant parasitemia (asymmetrical constrictions using oscillatory flow. This mechanism provides dramatically improved selectivity over previous biophysical methods by preventing the accumulation of cells in the filter microstructure to ensure that consistent filtration forces are applied to each cell. We show that our approach dramatically improves the sensitivity of malaria diagnosis performed using both microscopy and rapid diagnostic test by converting samples with difficult-to-detect parasitemia (0.1%). PMID:26768227
The impact of deformation on structural changes of the duplex steel
Directory of Open Access Journals (Sweden)
D. Kuc
2007-07-01
Full Text Available Purpose: Despite the many years’ research on the plasticity of duplex steels, it was impossible to conclusively determine the mechanisms for structure recovery during the plastic deformation. The paper will attempt to provide explanations for the changes taking place in the steel structure during the superplastic flow.Design/methodology/approach: After a solution heat treatment at 1250°C, the steel was subjected to cold deformation through rolling with the total 70% reduction. The specimens were tensioned in the “Instron” strength-testing machine at temperature 850°C at a rate of vr=15×10-3 mm/s in a 0.005Pa vacuum. Structural examination was carried out using light and electron microscopy. The micro-diffraction technique was applied to provide diffraction images with Kikuchi lines.Findings: A joint operation of structure reconstruction mechanisms during the deformation of the analyzed steel with the process of σ phase precipitation inhibiting further growth of the newly-formed grain has been determined.Practical implications: The capacity for increased deformability through combined thermo - mechanical processes, requiring a precise selection of the deformation parameters, has been indicatedOriginality/value: The results obtained are vital for designing an effective thermo - mechanical processing technology for the investigated steel.
Effectiveness of an educational intervention in schoolchildren from 8 to 11 presenting deforming
Directory of Open Access Journals (Sweden)
Odalis Acevedo Sierra
2011-04-01
Full Text Available Background: the practice of deforming oral habits may interfere with normal growth and development of the stomatognathic system and, consequently, cause dentomaxillofacial abnormalities. Objective: to analyze the effectiveness of an educational intervention in children from 8 to 11 presenting deforming oral habits. Methods: a quasi-experimental study was conducted before and after the intervention. The sample consisted of 67 children from the "Roberto Fleites" primary school in Cienfuegos, from January to September 2008. Different types of patterns and anomalies were identified for each child. The special program "Take Care of Your Smile" was applied weekly. A survey was applied to children, parents and educators before and after the application of educative and prevention actions and treatment. Results: deforming habits were eliminated in 66 % of cases (more frequent deforming habits were tongue protraction, bottle suction and nail biting and dentomaxillofacial abnormalities were reduced. The knowledge level of children, parents and educators was raised. Conclusions: deforming habits constitute a health problem that can be prevented in early stages in order to improve the harmony of the stomatognathic system components. An educational intervention can be effective for prevention in these cases.
Kaiser, Jasmin; Exner, Ulrike; Gier, Susanne; Hujer, Wolfgang
2010-05-01
In porous sedimentary rocks, fault zones are frequently accompanied by deformation bands. These structures are tabular zones of displacement, where grain rotation and in some cases grain fracturing result in a significant reduction in porosity. Core samples were analyzed close to large normal faults from the most productive hydrocarbon reservoir in the Vienna Basin (Austria), the Matzen oil field. The Badenian terrigeneous sandstones contain predominately quartz, feldspar and dolomite as sub-rounded, detrial grains and are weakly cemented by chlorite and kaolinite. Deformation bands occur as single bands of ca. 1-3 mm thickness and negligible displacement, as well as strands of several bands with up to 2 cm thickness and displacement of 1-2 cm. A dramatic porosity reduction can already be recognized macroscopically. In some samples, the corresponding reduction in permeability is highlighted by different degree of oil staining on either side of the bands. The mineralogical composition of the deformation bands compared to the host rock does not indicate any preferential cementation or diagenetic growth of clay minerals or calcite. Instead, clay minerals are slightly enriched in the host sediment. These observations suggest that the formation of deformation bands predates the cementation in the Matzen sands. Thus, we speculate that the porosity reduction is predominately caused by cataclastic grain size reduction. Identification of the grain scale processes of porosity and permeability reduction, in combination with the analysis of the spatial distribution and orientation of the deformation bands may provide valuable information on the reservoir properties and fluid migration paths.
Energy Technology Data Exchange (ETDEWEB)
Liu, F.C.; Xue, P. [Shenyang National Laboratory of Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Ma, Z.Y., E-mail: zyma@imr.ac.cn [Shenyang National Laboratory of Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)
2012-06-15
Highlights: Black-Right-Pointing-Pointer Microstructural evolution of extruded Al-Mg-Sc was divided into three stages. Black-Right-Pointing-Pointer Subgrain rotation and coalescence occurred in early strain hardening stage. Black-Right-Pointing-Pointer Dynamic recrystallization in the middle stage resulted in strain softening. Black-Right-Pointing-Pointer Grain boundary sliding and dynamic grain growth occurred in final deformation stage. Black-Right-Pointing-Pointer Friction stir processed alloy remained a random grain distribution at various strains. - Abstract: The microstructural evolution of unrecrystallized (extruded) and recrystallized (friction stir processed, FSP) Al-Mg-Sc alloys during superplastic straining was investigated using electron backscatter diffraction (EBSD). The unrecrystallized structure gradually transformed into a recrystallized structure, characterized by equiaxed grains, random boundary misorientation distribution and a weak texture at high strains. This evolution was divided into three stages based on true stress-strain curves and EBSD maps, i.e. subgrain rotation and coalescence in the early stage, dynamic recrystallization in the middle stage, and grain boundary sliding (GBS) and dynamic grain growth in the final stage. By comparison, the recrystallized grains in the FSP Al-Mg-Sc maintained a random distribution during the whole deformation process, however the grain size increased significantly with increasing strain, indicating that the main deformation mechanism was always GBS and dynamic grain growth. A deformation model was proposed to explain the microstructural evolution during superplastic deformation. The microstructure with the random boundary misorientations reaches a dynamic balance because the transformation between high-angle grain boundaries and low-angle grain boundaries is equivalent.
Partial discharge-induced crack growth in dielectric materials
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
Partial discharge(PD) of an air-filled semi-permeable crack in a dielectric material is studied based on the streamer-type discharge mechanism to explore the effects of applied mechanical-electric fields on crack growth.Within the frame of two-dimensional deformation,the electric field inside the crack is first derived by taking the crack deformation into account.Then,the effects of electric field before PD are discussed through considering the contribution of the induced electric field inside the deformed crack space to the total energy release rate.Finally,PD and its effects on crack growth are investigated.It is found that:(1) before PD,the applied electric field always retards crack growth;(2) during PD,the applied electric field can induce crack growth in dielectric materials.
Leslie, S. R.; Mahan, K. H.; Regan, S.; Williams, M. L.; Dumond, G.
2015-02-01
The deformation behavior of crustal materials in variably hydrated metamorphic environments can significantly influence the rheological and seismic properties of continental crust. Optical observations and electron backscatter diffraction (EBSD) analyses are used to characterize sillimanite deformation behavior in felsic tectonites from two deformation settings in the Athabasca granulite terrane, western Canadian Shield. Under estimated conditions of 0.8-1.0 GPa, 725-850 °C in the Cora Lake shear zone, the data suggest that sillimanite deformed by dislocation creep with slip in the [001] direction accompanied by subgrain rotation recrystallization. Where sillimanite locally remained undeformed, strain was concentrated in surrounding weaker phases. Under hydrated conditions of 0.4-0.6 GPa, 550-650 °C in the Grease River shear zone, textures and cathodoluminescence imaging point to dissolution-precipitation creep as the major deformation mechanism for sillimanite, resulting in synkinematic growth of foliation-parallel euhedral sillimanite in a preferred orientation with [001] parallel to the lineation. The results suggest that temperature, fluid content, and modal mineralogy of the surrounding phases may all have significant influence on sillimanite deformation but that preferential alignment of sillimanite [001] parallel to the lineation persists regardless of contrasts in the conditions or mechanisms of deformation.
Modelling deformation and fracture in confectionery wafers
International Nuclear Information System (INIS)
The aim of this research is to model the deformation and fracture behaviour of brittle wafers often used in chocolate confectionary products. Three point bending and compression experiments were performed on beam and circular disc samples respectively to determine the 'apparent' stress-strain curves in bending and compression. The deformation of the wafer for both these testing types was observed in-situ within an SEM. The wafer is modeled analytically and numerically as a composite material with a core which is more porous than the skins. X-ray tomography was used to generate a three dimensional volume of the wafer microstructure which was then meshed and used for quantitative analysis. A linear elastic material model, with a damage function and element deletion, was used and the XMT generated architecture was loaded in compression. The output from the FE simulations correlates closely to the load-deflection deformation observed experimentally
Modelling deformation and fracture in confectionery wafers
Energy Technology Data Exchange (ETDEWEB)
Mohammed, Idris K.; Charalambides, Maria N.; Williams, J. Gordon; Rasburn, John [Mechanical Engineering Department, Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom and Nestec York Ltd., Nestlé Product Technology Centre, Haxby Road, PO Box 204, York YO91 1XY (United Kingdom)
2015-01-22
The aim of this research is to model the deformation and fracture behaviour of brittle wafers often used in chocolate confectionary products. Three point bending and compression experiments were performed on beam and circular disc samples respectively to determine the 'apparent' stress-strain curves in bending and compression. The deformation of the wafer for both these testing types was observed in-situ within an SEM. The wafer is modeled analytically and numerically as a composite material with a core which is more porous than the skins. X-ray tomography was used to generate a three dimensional volume of the wafer microstructure which was then meshed and used for quantitative analysis. A linear elastic material model, with a damage function and element deletion, was used and the XMT generated architecture was loaded in compression. The output from the FE simulations correlates closely to the load-deflection deformation observed experimentally.
Anisotropic plasmas from axion and dilaton deformations
Donos, Aristomenis; Sosa-Rodriguez, Omar
2016-01-01
We construct black hole solutions of type IIB supergravity that are holographically dual to anisotropic plasmas arising from deformations of an infinite class of four-dimensional CFTs. The CFTs are dual to $AdS_5\\times X_5$, where $X_5$ is an Einstein manifold, and the deformations involve the type IIB axion and dilaton, with non-trivial periodic dependence on one of the spatial directions of the CFT. At low temperatures the solutions approach smooth domain wall solutions with the same $AdS_5\\times X_5$ solution appearing in the far IR. For sufficiently large deformations an intermediate scaling regime appears which is governed by a Lifshitz-like scaling solution. We calculate the DC thermal conductivity and some components of the shear viscosity tensor.
Deformed phase spaces with group valued momenta
Arzano, Michele
2016-01-01
We introduce a general framework for describing deformed phase spaces with group valued momenta. Using techniques from the theory of Poisson-Lie groups and Lie bi-algebras we develop tools for constructing Poisson structures on the deformed phase space starting from the minimal input of the algebraic structure of the generators of the momentum Lie group. The tools developed are used to derive Poisson structures on examples of group momentum space much studied in the literature such as the $n$-dimensional generalization of the $\\kappa$-deformed momentum space and the $SL(2, \\mathbb{R})$ momentum space in three space-time dimensions. We discuss classical momentum observables associated to multi-particle systems and argue that these combine according the usual four-vector addition despite the non-abelian group structure of momentum space.
Realistic face modeling based on multiple deformations
Institute of Scientific and Technical Information of China (English)
GONG Xun; WANG Guo-yin
2007-01-01
On the basis of the assumption that the human face belongs to a linear class, a multiple-deformation model is proposed to recover face shape from a few points on a single 2D image. Compared to the conventional methods, this study has the following advantages. First, the proposed modified 3D sparse deforming model is a noniterative approach that can compute global translation efficiently and accurately. Subsequently, the overfitting problem can be alleviated based on the proposed multiple deformation model. Finally, by keeping the main features, the texture generated is realistic. The comparison results show that this novel method outperforms the existing methods by using ground truth data and that realistic 3D faces can be recovered efficiently from a single photograph.
Modified Lorentz transformations in deformed special relativity
Salesi, G; Deleidi, L; Peruzza, R A
2016-01-01
We extend a recent approach to Deformed Special Relativity based on deformed dispersion laws, entailing modified Lorentz transformations and, at the same time, noncommutative geometry and intrinsically discrete spacetime. In so doing we obtain the explicit form of the modified Lorentz transformations for a special class of modified momentum-energy relations often found in literature and arising from elementary particle physics. Actually, our theory looks as a very simple and natural extension of special relativity to include a momentum cut-off at the Planck scale. In particular, the new Lorentz transformations do imply that for high boost speed ($V \\sim c$) the deformed Lorentz factor does not diverge as in ordinary relativity, but results to be upperly bounded by a large finite value of the order of the ratio between the Planck mass and the particle mass. We also predict that a generic boost leaves unchanged Planck energy and momentum, which result invariant with respect to any reference frame.
A Small Deformation of a Simple Theory
Buican, Matthew
2016-01-01
We study an interesting relevant deformation of the simplest interacting N=2 SCFT---the original Argyres-Douglas (AD) theory. We argue that, although this deformation is not strictly speaking Banks-Zaks like (certain operator dimensions change macroscopically), there are senses in which it constitutes a mild deformation of the parent AD theory: the exact change in the "a" anomaly is small and is essentially saturated at one loop. Moreover, contributions from IR operators that have a simple description in the UV theory reproduce a particular limit of the IR index to a remarkably high order. These results lead us to conclude that the IR theory is an N=1 SCFT with the smallest-known "a" and "c" central charges for an interacting SCFT in four dimensions.
Optomechanical deformation and strain in elastic dielectrics
Sonnleitner, Matthias; Ritsch, Helmut
2012-01-01
Light forces induced by scattering and absorption in elastic dielectrics lead to local density modulations and deformations. These perturbations in turn modify light propagation in the medium and generate an intricate nonlinear response. We generalise an analytic approach where light propagation in one-dimensional media of inhomogeneous density is modelled as a result of multiple scattering between polarizable slices. Using the Maxwell stress tensor formalism we compute the local optical forces and iteratively approach self-consistent density distributions where the elastic back-action balances gradient- and scattering forces. For an optically trapped dielectric we derive the nonlinear dependence of trap position, stiffness and total deformation on the object's size and field configuration. Generally trapping is enhanced by deformation, which exhibits a periodic change between stretching and compression. This strongly deviates from qualitative expectations based on the change of photon momentum of light cross...
Tidal deformations of a spinning compact object
Pani, Paolo; Maselli, Andrea; Ferrari, Valeria
2015-01-01
The deformability of a compact object induced by a perturbing tidal field is encoded in the tidal Love numbers, which depend sensibly on the object's internal structure. These numbers are known only for static, spherically-symmetric objects. As a first step to compute the tidal Love numbers of a spinning compact star, here we extend powerful perturbative techniques to compute the exterior geometry of a spinning object distorted by an axisymmetric tidal field to second order in the angular momentum. The spin of the object introduces couplings between electric and magnetic deformations and new classes of induced Love numbers emerge. For example, a spinning object immersed in a quadrupolar, electric tidal field can acquire some induced mass, spin, quadrupole, octupole and hexadecapole moments to second order in the spin. The deformations are encoded in a set of inhomogeneous differential equations which, remarkably, can be solved analytically in vacuum. We discuss certain subtleties in defining the multipole mom...
Modelling deformation and fracture in confectionery wafers
Mohammed, Idris K.; Charalambides, Maria N.; Williams, J. Gordon; Rasburn, John
2015-01-01
The aim of this research is to model the deformation and fracture behaviour of brittle wafers often used in chocolate confectionary products. Three point bending and compression experiments were performed on beam and circular disc samples respectively to determine the 'apparent' stress-strain curves in bending and compression. The deformation of the wafer for both these testing types was observed in-situ within an SEM. The wafer is modeled analytically and numerically as a composite material with a core which is more porous than the skins. X-ray tomography was used to generate a three dimensional volume of the wafer microstructure which was then meshed and used for quantitative analysis. A linear elastic material model, with a damage function and element deletion, was used and the XMT generated architecture was loaded in compression. The output from the FE simulations correlates closely to the load-deflection deformation observed experimentally.
Nucleus spectroscopy: extreme masses and deformations
International Nuclear Information System (INIS)
The author proposes a synthesis of research activities performed since 1995 in the field of experimental nuclear physics, and more particularly in the investigation of two nucleus extreme states: deformation on the one hand, heavy and very heavy nuclei on the other hand. After a presentation of the context of investigations on deformation, rotation, and heavy nuclei, he gives an overview of developments regarding instruments (gamma spectrometers, detection of fission fragments, and detection at the focal plane of spectrometers or separators) and analysis techniques. Experiments and results are then reported and discussed, concerning super-deformed states with a high angular moment, spectroscopy of neutron-rich nuclei, very heavy nuclei close to nucleus map borders. He finally draws perspectives for middle and long term studies on the heaviest nuclei
Yang-Baxter deformations of Minkowski spacetime
Jun-ichi, Sakamoto
2016-01-01
We discuss Yang-Baxter sigma deformations of 4D Minkowski spacetime proposed recently. To avoid the degeneracy of the standard bilinear form associated with the familiar coset ISO(1,3)/SO(1,3), we consider a slice of AdS5 in Poincaré coordinates by embedding the 4D Poincaré group into the 4D conformal group SO(2,4). With this procedure we present the metrics and B-fields as Yang-Baxter deformations which correspond to well-known backgrounds such as T-duals of Melvin backgrounds, Hashimoto-Sethi and Spradlin-Takayanagi-Volovich backgrounds, pp-waves, and T-duals of dS4 and AdS4. Finally we consider a deformation with a classical r-matrix of Drinfeld-Jimbo type and explicitly derive the associated metric and B-field.
Plastic deformation in a metallic granular chain
Musson, Ryan W.; Carlson, William
2016-03-01
Solitary wave response was investigated in a metallic granular chain-piston system using LS-DYNA. A power law hardening material model was used to show that localized plastic deformation is present in a metallic granular chain for an impact velocity of 0.5 m/s. This loss due to plastic deformation was quantified via impulse, and it was shown that the loss scales nearly linearly with impact velocity. Therefore, metallic grains may not be suitable for devices that require high-amplitude solitary waves. There would be too much energy lost to plastic deformation. One can assume that ceramics will behave elastically; therefore, the response of an aluminum oxide granular chain was compared to that of a steel chain.
Deformation behaviour of soft particles: a review
Energy Technology Data Exchange (ETDEWEB)
Liu, K.-K. [Institute of Science and Technology in Medicine, School of Medicine (Hartshill Campus), Keele University, Stoke-on-Trent, ST4 7QB (United Kingdom)
2006-06-07
The study of soft particle deformation is of paramount importance for the advancement of fundamental colloidal science as well as its biomedical applications, particularly in drug delivery and cell mechanics/adhesion. Recent developments of both theoretical modelling and experimental techniques have made it possible to measure the deformation behaviour of a single micro-/nano-particle under both adhesive and non-adhesive deformation and, therefore, to facilitate the determination of its mechanical and interfacial properties. This review aims to introduce several modern experimental techniques, such as atomic force microscopy, the micro-compression method and reflectance interference contrast microscopy, and a number of theoretical models, which have been applied to characterize the mechanical and interfacial properties of the soft particles in a quantitative manner. More specifically, their recent applications to biomimetic/biological particles or vesicles, which normally inherit non-linear elasticity and inhomogeneous structure, will also be reviewed. (topical review)
Cyclic deformation of metals and alloys
International Nuclear Information System (INIS)
Phenomena associated with rapid hardening or softening caused by cyclic straining in the early stages of fatigue life of metals and alloys are reviewed. The factors which control these phenomena are described and also the dislocation structures which are associated with them. In so far as the mechanisms of cyclic deformation are understood these too are described and a number of parallels between cyclic and unidirectional deformation are pointed out. A similar approach is then taken for materials which contain second phases for strength. Note that these studies apply to cycling at ambient temperatures or below. High-temperature cyclic deformation is beyond the scope of this review. An engineering method of predicting cyclic stress-strain response from tensile testing data is examined in the light of the fundamental knowledge described, and is shown to be severely limited. A method of improving such prediction by introducing additional microstructural information which is readily available is suggested. 117 references
Deformation of niobium crystals containing zirconia particles
International Nuclear Information System (INIS)
The effect of zirconia particles on the deformation of niobium single crystals has been studied over the temperature range 4K to 373K. Transmission electron microscopy was used to characterize the dispersion and to observe directly the interaction between dislocations and the precipitate particles. Large numbers of prismatic loops were observed lying in rows along the direction of the primary Burgers vector. At high deformation temperatures the stress-strain curves showed low, linear hardening and as the temperature was reduced this was preceded by a small parabolic stage. At the lowest temperatures of deformation mechanical twinning occurred. The slip plane, determined by multisurface analysis, was usually (1-bar01) but at 77K (3-bar12) was observed. The particles did not have a dramatic effect on either the stress-strain curves or the parameters defining thermally-activated flow but raised the flow stress at all temperatures and slightly reduced the tendency to twin
Zollinger, Tawnia J; Backues, Kay A; Burgos-Rodriguez, Armando G
2005-12-01
Three hand-raised American flamingo (Phoenicopterus ruber ruber) chicks and one hand-raised Chilean flamingo (Phoenicopterus ruber chilensis) developed valgus angular limb deformities of the proximal tarsometatarsal bone. All flamingos underwent surgical correction to unequally retard the growth plate using transphyseal bridging. Positive profile pins were placed in the proximal epiphysis and distal to the growth plate in the metaphysis on the convex side of the affected tarsometatarsus. Various banding techniques were used in each flamingo to create tension. Three of the four flamingos responded in 7-14 days with correction or slight overcorrection of the valgus limb deformity. The fourth flamingo's leg deformity did not improve for reasons thought to be related to improper implant placement. Growth plate retardation by transphyseal bridging proved successful in correcting valgus limb deformity of the proximal tarsometatarsus. This technique may be considered as an option for correction of angular limb deformities of the proximal tarsometatarsus in flamingos less than 90-120 days of age. PMID:17312728
Growth Accounting and Growth Processes
Jahangir Aziz
1996-01-01
The standard growth accounting framework, which weights various inputs by their factor shares to measure their contributions to output growth, is known to underestimate the contribution of inputs in the presence of externalities and increasing returns. This paper develops a model in which, in the absence of such departures from the standard neoclassical framework, growth can occur through either embodied technological progress or firms replication of existing technology. The standard growth a...
Salt lake deformation detected from space
Ruch, J.; J. K. Warren; F. Risacher; Thomas R. Walter; Lanari, R.
2012-01-01
To investigate the spatiotemporal evolution of salars in the Atacama Desert in Chile (24-26 degrees S), we use a deformation time series retrieved by applying satellite radar interferometry techniques for the period from 2003 to 2008. We find that all 12 salars surveyed are actively deforming, with displacement rates from -1.4 to 1.5 cm/yr in the satellite line-of-sight direction. Displacement rates are mostly confined to the salars themselves, and are generally constant in time and space. To...
Reciprocating motion of active deformable particles
Tarama, M.; Ohta, T.
2016-05-01
Reciprocating motion of an active deformable particle in a homogeneous medium is studied theoretically. For generality, we employ a simple model derived from symmetry considerations for the center-of-mass velocity and elliptical and triangular deformations in two dimensions. We carry out, for the first time, a systematic investigation of the reciprocating motion of a self-propelled particle. It is clarified that spontaneous breaking of the front-rear asymmetry is essential for the reciprocating motion. Moreover, two routes are found for the formation of the reciprocating motion. One is a bifurcation from a motionless stationary state. The other is destabilisation of an oscillatory rectilinear motion.
Bulk metallic glasses deform via slip avalanches.
Antonaglia, James; Wright, Wendelin J; Gu, Xiaojun; Byer, Rachel R; Hufnagel, Todd C; LeBlanc, Michael; Uhl, Jonathan T; Dahmen, Karin A
2014-04-18
For the first time in metallic glasses, we extract both the exponents and scaling functions that describe the nature, statistics, and dynamics of slip events during slow deformation, according to a simple mean field model. We model the slips as avalanches of rearrangements of atoms in coupled shear transformation zones (STZs). Using high temporal resolution measurements, we find the predicted, different statistics and dynamics for small and large slips thereby excluding self-organized criticality. The agreement between model and data across numerous independent measures provides evidence for slip avalanches of STZs as the elementary mechanism of inhomogeneous deformation in metallic glasses. PMID:24785049
Governor model for asymmetric deformed nuclei
International Nuclear Information System (INIS)
The governor model is extended to include the asymmetric shape of nuclei which allows a simultaneous analysis of the data for both the ground state and the γ-vibrational bands in deformed even-even nuclei. The rotationally invariant core is assumed to be a spheroid with an axis of symmetry parallel to the axis of rotation. The calculations are carried out under the assumption of no stretching. The static γ-deformation results are compared with the VMI(ARM) and Krutov values, and the calculated energies are in good agreement with the experimental data
Numerical Modeling of Subglacial Sediment Deformation
DEFF Research Database (Denmark)
Damsgaard, Anders
2015-01-01
Glacier and ice sheet mass balance is sensitive to climate change. The geological record has revealed that the polar ice sheets in the past responded rapidly to periods of warming, most likely caused by dynamic changes in ice flow patterns. The rapid ice-sheet dynamical changes observed in the past......, however, viscous effects from meltwater deformation can provide additional rate-dependent strengthening. The strengthening may act to stabilize patches of the deforming bed, triggering differential advection and hydrological exchange between the bed and the ice-bed interface. We also show that granular...
On the BRST invariance of field deformations
International Nuclear Information System (INIS)
Topological quantum field theories are distinguished by a BRST symmetry corresponding to local field deformations. We investigate in this letter to what extent an arbitrary quantum field theory may be related to this BRST invariance. We demonstrate that at the expense of having to add extra variables (but without changing the physics) one may always extend to symmetry of an arbitrary action to include local field deformations. New avenues for gauge-fixing are then available. Examples are worked out for Yang-Mills theories. (orig.)
Cut Locus Construction using Deformable Simplicial Complexes
DEFF Research Database (Denmark)
Misztal, Marek Krzysztof; Bærentzen, Jakob Andreas; Anton, François;
2011-01-01
In this paper we present a method for appproximating cut loci for a given point p on Riemannian 2D manifolds, closely related to the notion of Voronoi diagrams. Our method finds the cut locus by advecting a front of points equally distant from p along the geodesics originating at p and finding the...... lines of self-intersections of the front in the parametric space. This becomes possible by using the deformable simplicial complexes (DSC, [1]) method for deformable interface tracking. DSC provide a simple collision detection mechanism, allows for interface topology control, and does not require the...
Deformation equivalence of affine ruled surfaces
Flenner, Hubert; Kaliman, Shulim; ZAIDENBERG, MIKHAIL
2013-01-01
A smooth family $\\varphi:\\mathcal V\\to S$ of surfaces will be called {\\em completable} if there is a logarithmic deformation $(\\bar {\\mathcal V},{\\mathcal D})$ over $S$ so that ${\\mathcal V}=\\bar{\\mathcal V}\\backslash {\\mathcal D}$. Two smooth surfaces $V$ and $V'$ are said to be deformations of each other if there is a completable flat family ${\\mathcal V}\\to S$ of smooth surfaces over a connected base so that $V$ and $V'$ are fibers over suitable points $s,s'\\in S$. This relation generates ...
Nuclear deformation from fast neutron scattering
International Nuclear Information System (INIS)
Investigations of nuclear deformation through fast neutron scattering are reviewed in some detail. In recent years, experimental methods and techniques have been considerably improved and have permitted precise cross section measurements for neutron elastic scattering and inelastic scattering to the first collective excited levels of a large number of vibrational nuclei. Analyses of these experimental data using the conventional non-spherical optical potential model are discussed with special emphasis on the choice of the optical potential parameterization. The nuclear deformations derived from these analyses are presented and compared to results obtained using other nuclear probes, and to predictions from theoretical calculations
Nonlinear Continuum Mechanics and Large Inelastic Deformations
Dimitrienko, Yuriy I
2011-01-01
This book provides a rigorous axiomatic approach to continuum mechanics under large deformation. In addition to the classical nonlinear continuum mechanics - kinematics, fundamental laws, the theory of functions having jump discontinuities across singular surfaces, etc. - the book presents the theory of co-rotational derivatives, dynamic deformation compatibility equations, and the principles of material indifference and symmetry, all in systematized form. The focus of the book is a new approach to the formulation of the constitutive equations for elastic and inelastic continua under large def
Management of post burn hand deformities
Directory of Open Access Journals (Sweden)
Sabapathy S
2010-10-01
Full Text Available The hand is ranked among the three most frequent sites of burns scar contracture deformity. One of the major determinants of the quality of life in burns survivors is the functionality of the hands. Burns deformities, although largely preventable, nevertheless do occur when appropriate treatment is not provided in the acute situation or when they are part of a major burns. Reconstructive procedures can greatly improve the function of the hands. Appropriate choice of procedures and timing of surgery followed by supervised physiotherapy can be a boon for a burns survivor.
Schreiber, U
2004-01-01
Motivated by the representation of the super Virasoro constraints as generalized Dirac-K{\\"a}hler constraints $(d \\pm d^\\dagger)|\\psi> = 0$ on loop space, examples of the most general continuous deformations $d \\to e^{-W} d e^W$ are considered which preserve the superconformal algebra at the level of Poisson brackets. The deformations which induce the massless NS and NS-NS backgrounds are exhibited. A further 2-form background is found, which is argued to be related to the RR 2-form. Hints for a manifest realization of S-duality in terms of an algebra isomorphism are discussed.
Geometric Total Variation for Texture Deformation
DEFF Research Database (Denmark)
Bespalov, Dmitriy; Dahl, Anders Lindbjerg; Shokoufandeh, Ali
In this work we propose a novel variational method that we intend to use for estimating non-rigid texture deformation. The method is able to capture variation in grayscale images with respect to the geometry of its features. Our experimental evaluations demonstrate that accounting for geometry of...... features in texture images leads to significant improvements in localization of these features, when textures undergo geometrical transformations. Accurate localization of features in the presense of unkown deformations is a crucial property for texture characterization methods, and we intend to expoit...
Tensile Deformation of Polyethylenes: Crystallinity Effects
Crist, Buckley; Metaxas, Costas
2004-03-01
The crystalline fraction of polyethylene can be reduced by increasing the cooling rate, the molecular weight or the fraction of comonomer. All three methods have been used in this study of tensile deformation which shows that true stress - true strain behavior depends systematically on morphology. The dependence of uniaxial yield stress on crystal thickness is well understood in terms of dislocation nucleation. Post yield flow is dominated by the strain hardening rate that is larger in polyethylenes of lower crystallinity. Noncrystalline polymer evidently reduces the plastic compliance while providing for elastic (reversible) strains. These observations are examined in terms of old and new theories for deformation of semicrystalline polymers.
On the BRST invariance of field deformations
International Nuclear Information System (INIS)
Topological quantum field theories are distinguished by a BRST symmetry corresponding to local field deformations. We investigate in this letter to what extent an arbitrary quantum field theory may be related to this BRST invariance. We demonstrate that at the expense of having to add extra variables (but without changing the physics) one may always extend the symmetry of an arbitrary action to include local field deformations. New avenues for gauge-fixing are then available. Examples are worked out for Yang-Mills theories. (orig.)
Asperity deformation during running-in
DEFF Research Database (Denmark)
Jakobsen, Jørgen; Sivebæk, Ion Marius
2010-01-01
Asperities loaded in pure rolling against a hard, smooth surface will often be deformed at the first contact event and will thereby experience high normal stress, presumably of a magnitude near the Vickers hardness of the softer material. Continued running-in can be imagined to develop into lower...... stress levels and an increase of contact area. An asperity model simulating a running-in process of rough surfaces with lengthy protractions in the rolling direction was investigated. After a limited range of only about 104 contact events a state of very low deformation rate was found....
Asperity deformation during running-in
DEFF Research Database (Denmark)
Jakobsen, Jørgen; Sivebæk, Ion Marius
Asperities loaded in pure rolling against a hard, smooth surface will often be deformed at the first contact event and will thereby experience high normal stress, presumably of a magnitude near the Vickers hardness of the softer material. Continued running-in can be imagined to develop into lower...... stress levels and an increase of contact area. An asperity model simulating a running-in process of rough surfaces with lengthy protractions in the rolling direction was investigated. After a limited range of only about 104 contact events a state of very low deformation rate was found....
Supermultiplet of $\\beta-$deformations from twistors
Milián, Segundo P
2016-01-01
We consider the supermultiplet of linearized beta-deformation of $\\mathcal{N}=4$ Super Yang-Mills(SYM). It was previously studied on the gravitational side. We study the supermultiplet of beta-deformations on the field theory side and we compare two finite-dimensional representations of $psl(4|4,\\bf{R})$ algebra. We show that they are related by an intertwining operator. We develop a twistor-based approach which could be useful for studying other finite-dimensional and nonunitary representations in AdS/CFT correspondence.
International Nuclear Information System (INIS)
Highlights: • Microtexture development of deformed oxide layers is investigated. • Magnetite shares the {0 0 1} fibre texture with wustite. • Hematite develops the {0 0 0 1} basal fibre parallel to the oxide growth. • Stress relief and ion vacancy diffusion mechanism for magnetite seam. - Abstract: Electron backscatter diffraction (EBSD) analysis has been presented to investigate the microstructure and microtexture evolutions of deformed oxide scale formed on a microalloyed steel during hot rolling and accelerated cooling. Magnetite and wustite in oxide layers share a strong {0 0 1} and a weak {1 1 0} fibres texture parallel to the oxide growth. Trigonal hematite develops the {0 0 0 1} basal fibre parallel to the crystallographic plane {1 1 1} in magnetite. Taylor factor estimates have been conducted to elucidate the microtexture evolution. The fine-grained magnetite seam adjacent to the substrate is governed by stress relief and ions vacancy diffusion mechanism
Modeling Stromatolite Growth Under Oscillatory Flows
Patel, H. J.; Gong, J.; Tice, M. M.
2014-12-01
Stromatolite growth models based on diffusion limited aggregation (DLA) has been fairly successful at producing features commonly recognized in stromatolitic structures in the rock record. These models generally require slow mixing of solutes at time scales comparable to the growth of organisms and largely ignore fluid erosions. Recent research on microbial mats suggests that fluid flow might have a dominant control on the formation, deformation and erosion of surface microbial structures, raising the possibility that different styles of fluid flow may influence the morphology of stromatolites. Many stromatolites formed in relatively high energy, shallow water environments under oscillatory currents driven by wind-induced waves. In order to investigate the potential role of oscillatory flows in shaping stromatolites, we are constructing a numerical model of stromatolite growth parameterized by flume experiments with cyanobacterial biofilms. The model explicitly incorporates reaction-diffusion processes, surface deformation and erosion, biomass growth, sedimentation and mineral precipitation. A Lattice-Boltzmann numerical scheme was applied to the reaction-diffusion equations in order to boost computational efficiency. A basic finite element method was employed to compute surface deformation and erosion. Growth of biomass, sedimentation and carbonate precipitation was based on a modified discrete cellular automata scheme. This model will be used to test an alternative hypothesis for the formation of stromatolites in higher energy, shallow and oscillatory flow environments.
DEFF Research Database (Denmark)
Becker, Hanka; Pantleon, Wolfgang
2013-01-01
Commercially pure titanium was tensile tested at different strain rates between 2.2×10−4s−1 and 6.7×10−1s−1 to characterize the strain rate dependence of plastic deformation and the dominating deformation mechanisms. From true stress-true plastic strain curves, three distinct work-hardening stages...... {101¯2}〈101¯1〉 tensile twinning. Based on the microstructural findings and the strain rate sensitivity, deformation mechanism maps are constructed....
A mixture approach to investigate interstitial growth in engineering scaffolds.
Vernerey, Franck J
2016-04-01
Controlling biological growth within a cell-laden polymeric scaffold is a critical challenge in the tissue engineering community. Indeed, construct growth must often be balanced with scaffold degradation and is often coupled to varying degrees of deformation that originate from swelling, external forces and the effects of confinement. These factors have been shown to affect growth in many ways, but to date, our understanding is mostly qualitative. While cell sensing, molecular transport and scaffold/tissue interactions are believed to be important players, it will be critical to quantify, predict and control these effects in order to eventually optimize tissue growth in the laboratory. The aim of this paper was thus to provide a theoretical framework to better understand how the scaffold-mediated mechanisms of transport, deposition (and possibly degradation) and elasticity affect the overall growth of a tissue subjected to finite deformations. We propose a formulation in which the macroscopic evolutions in tissue size, density as well as the appearance of residual stresses can be directly related to changes in internal composition by considering three fundamental principles: mechanical equilibrium, chemical equilibrium and molecular incompressibility. The resulting model allows us to pay particular attention to features that are critical to the interaction between growth and deformation: osmotic pressure and swelling, the strain mismatch between old and newly deposited material as well as the mechano-sensitive cell-mediated production. We show that all of these phenomena may indeed strongly affect the overall growth of a construct under finite deformations. PMID:26047777
Anticavitation and Differential Growth in Elastic Shells
Moulton, Derek E.
2010-07-22
Elastic anticavitation is the phenomenon of a void in an elastic solid collapsing on itself. Under the action of mechanical loading alone typical materials do not admit anticavitation. We study the possibility of anticavitation as a consequence of an imposed differential growth. Working in the geometry of a spherical shell, we seek radial growth functions which cause the shell to deform to a solid sphere. It is shown, surprisingly, that most material models do not admit full anticavitation, even when infinite growth or resorption is imposed at the inner surface of the shell. However, void collapse can occur in a limiting sense when radial and circumferential growth are properly balanced. Growth functions which diverge or vanish at a point arise naturally in a cumulative growth process. © 2010 Springer Science+Business Media B.V.
Mechanical Deformation of Ship Stern-Shaft Mechanical Face Seals
Institute of Scientific and Technical Information of China (English)
朱汉华; 刘正林; 温诗铸; 严新平
2004-01-01
In ship propeller shaft systems, the shaft seal is a mechanical face seal, which includes a stationary metal seal ring and a rotating ring.The seal faces are deformed with different loads.The deformation of the seal faces affects the performance of mechanical face seals, which leads to water leakage, so the seal face deformation must be analyzed.A mechanics model with deformation equations was developed to describe ship stern-shaft seals.An example was given to verify the deformation equations.The solution of the deformation equations gives a theoretical basis for the analysis of seal leakage and improvements of seal structures.
On deformations of Yang-Mills algebras
Movshev, M.
2005-01-01
This is a next paper from a sequel devoted to algebraic aspects of Yang-Mills theory. We undertake a study of deformation theory of Yang-Mills algebra YM - a ``universal solution'' of Yang-Mills equation. We compute (cyclic) (co)homology of YM.
The $q$-deformed Bogoliubov transformations
Arraut, Ivan
2016-01-01
An algebraic generalization of the Bogoliubov transformation is introduced in the context of $q$-commutativity. The set of coefficients are promoted to operators where we work with a $q$-deformed action over the Bosonic algebra together with some generalized trigonometric hyperbolic identities. We make the analogous extension for the fermionic algebra.
Remeshing in analysis of large plastic deformations
DEFF Research Database (Denmark)
Pedersen, Thomas Ø
1998-01-01
Very distorted elements in a finite element computation will affect the results in a negative way. In applications where large plastic deformations are present, the mesh often deteriorates so badly, that remeshing is the only option to avoid a breakdown in the numerical computations. In the present...
Hydroxyl induced eclogite fabric and deformation mechanism
Institute of Scientific and Technical Information of China (English)
ZHANG Junfeng; JIN Zhenmin; Harry W. Green II
2005-01-01
Eclogites from orogens often show strong plastic deformation and high hydroxyl content. We have studied the correlation between crystallographic preferred orientations of garnet and omphacite from natural eclogites with their hydroxyl contents using the electron back-scat- tered diffraction technique. The results show: 1) Omphacite has typical L-type or SL-type crystrallographic preferred orientations, that is, [001] is distributed in a girdle in the foliation plane with a maximum parallel to lineation; (010) is distributed in a girdle normal to the lineation with a maximum parallel to the foliation plane, suggesting a shear dominant deformation regime. Omphacite fabrics do not vary significantly with hydroxyl content, although the hydrous component may cause lower flow strength. 2) Hydroxyl can influence significantly flow properties of garnet in eclogite. Garnets behave as rigid bodies under low temperature and dry conditions. Grain boundary processes will dominate the deformation and lower the flow strength of garnet under high water fugacity conditions. Garnets show no crystallographic preferred orientation in both cases. These results may have important implications for a better understanding of deformation mechanisms and associated fluid activities during deep subduction and exhumation processes.
Strict Almost Non-Abelian Deformations
Much, A
2015-01-01
An almost non-abelian extension of the Rieffel deformation is presented in this work. The non-abelicity comes into play by the introduction of unitary groups which are dependent of the infinitesimal generators of $SU(n)$. This extension is applied to quantum mechanics and quantum field theory.
Prestudy Oskarshamn. Soils, rocks and deformation zones
International Nuclear Information System (INIS)
Soil and geology of the Oskarshamn area are described, as well as deformation zones and seismicity. Several areas of the inland are judged to be potentially well suited for a spent fuel repository. In the Simpevarp peninsula, it may be difficult to locate a rock mass big enough, between the fracture zones, to host a repository
Classification and versal deformation of generalized flags
Puerta Coll, Xavier
2003-01-01
A natural equivalence relation can be considered in the generalized flag manifold. First we give a complete set of invariants of it as well as a canonical matrix description of the classes. Next we consider parametric flags. We give a miniversal deformation for the above canonical form and we use it to characterize the stable flags. Peer Reviewed
Deformation processes in polycrystalline aggregates of gypsum
de Meer, S.
1995-01-01
On the basis of both field and laboratory studies it is well established that polycrystalline gypsum is one of the weakest and most ductile rock materials found in the Earth's crust (e.g. Heard & Rubey, 1966; Murrell & Ismail, 1976; Baumann, 1985; Jordan, 1988; 1991; 1994). The deformation and densi
Postseismic Deformation in the Central Andaman Islands
Puchakayala, J. P.; Smalley, R.; Bilham, R.; Lowry, A.; Batacharjee, A.
2005-12-01
The December 26, 2004 Sumatra-Andaman earthquake generated horizontal displacements at Port Blair totaling 3.08 m and vertical subsidence of 0.6-0.9m, indicating 1.6 m arc normal and 6.2±0.6 m dextral coseismic slip on the plate interface. Displacements occurred steadily beginning 10 minutes after the mainshock and were largely complete within 30 minutes after the mainshock. Although continuous GPS measurements were not initiated until 24 days after the mainshock by us and other groups, it is possible from these records to inferthat postseismic deformation in this interval did not exceed 10% of the coseismic displacements. Postseismic deformation continues at present at an exponentially decaying rate. Between January and June 2005, Port Blair has moved 4.5 cm south, 15 cm west and 10 cm up, suggesting postseismic slip downdip of the coseismic rupture and/or viscoelastic relaxation of the mantle. Elastic models of the region based on GPS coseismic slip observations provided by Center for Earth Science Studies (CESS) are consistent with reports of uplift from the islands: North Sentinel (50 km west of Port Blair) rose by 1.0±0.2 m, Port Blair and Middle Andaman subsided by about 1 m and Havelock Island (32 km east) showed no significant vertical deformation. We report data from five campaign sites in the Andaman Islands measured thrice since the earthquake that permit viscoelastic and afterslip models of postseismic deformation to be developed and assessed.
Creep deformation of TD--nickel chromium
International Nuclear Information System (INIS)
The creep behavior of thoria dispersed nickel-chromium (TD-NiCr) was examined at 10930C. Major emphasis was placed on 1) the effects of the material and the test related variables (grain size, temperature, stress, strain and strain rate) on the deformation characteristics, and 2) the evaluation of single crystal TD-NiCr material produced by a directional recrystallization technique. Creep activation enthalpies were found to increase with increasing grain size reaching maximum values for the single crystal TD-NiCr. Stress exponent of the steady state creep rate was also significantly higher for the single crystal material as compared with that determined for the polycrystalline TD-NiCr. The elevated temperature deformation of TD-NiCr was analyzed in terms of two parallel-concurrent processes: 1) diffusion controlled grain boundary sliding and 2) dislocation motion. The characteristics of the dislocation motion deformation mode (as observed in the single crystal TD-NiCr) suggest that strong particle-dislocation interactions are present. The relative contributions of dislocation motion and grain boundary sliding in TD-NiCr were estimated. In creep, grain boundary sliding was found to predominate for the small, equiaxed grain structures, whereas the dislocation deformation mode became significant for only the large grain TD-NiCr and the single crystal material
Deformable Mirrors Capture Exoplanet Data, Reflect Lasers
2014-01-01
To image and characterize exoplanets, Goddard Space Flight Center turned to deformable mirrors (DMs). Berkeley, California-based Iris AO, Inc. worked with Goddard through the SBIR program to improve the company’s microelectromechanical DMs, which are now being evaluated and used for biological research, industrial applications, and could even be used by drug manufacturers.
Intermetallic alloys: Deformation, mechanical and fracture behaviour
International Nuclear Information System (INIS)
The state of the art in intermetallic alloys development with particular emphasis on deformation, mechanical and fracture behaviour is documented. This review paper is prepared to lay the ground stones for a future work on mechanical property characterization and fracture behaviour of intermetallic alloys at GKSS. (orig.)
Homotopy coherent nerve in Deformation theory
Hinich, V.
2007-01-01
In this note we explain that homotopy coherent simplicial nerve has to used intead of the standard definition in the author's papers on formal deformation theory. A convenient version of the notion of fibered category is presented which is useful once one works with simplicial categories.
Rigid and deformable pick and place algorithms
Martí Carrillo, Felip; Alenyà Ribas, Guillem
2014-01-01
This technical report explains the packages used in the WAM robot to pick and place cloth or tableware objects. The goal was to check if the WAM arm robot could perform several movements to fold and unfold deformables and manipulate some tableware objects. Eight different nodes have been implemented following a generic and a modular design in order to allow scalability and adaptability.
Monte Carlo dose mapping on deforming anatomy
Zhong, Hualiang; Siebers, Jeffrey V.
2009-10-01
This paper proposes a Monte Carlo-based energy and mass congruent mapping (EMCM) method to calculate the dose on deforming anatomy. Different from dose interpolation methods, EMCM separately maps each voxel's deposited energy and mass from a source image to a reference image with a displacement vector field (DVF) generated by deformable image registration (DIR). EMCM was compared with other dose mapping methods: energy-based dose interpolation (EBDI) and trilinear dose interpolation (TDI). These methods were implemented in EGSnrc/DOSXYZnrc, validated using a numerical deformable phantom and compared for clinical CT images. On the numerical phantom with an analytically invertible deformation map, EMCM mapped the dose exactly the same as its analytic solution, while EBDI and TDI had average dose errors of 2.5% and 6.0%. For a lung patient's IMRT treatment plan, EBDI and TDI differed from EMCM by 1.96% and 7.3% in the lung patient's entire dose region, respectively. As a 4D Monte Carlo dose calculation technique, EMCM is accurate and its speed is comparable to 3D Monte Carlo simulation. This method may serve as a valuable tool for accurate dose accumulation as well as for 4D dosimetry QA.
Nail bed injuries and deformities of nail
Directory of Open Access Journals (Sweden)
R Ravindra Bharathi
2011-01-01
Full Text Available Nail bed injuries are common and management of these requires good knowledge of the nail bed anatomy. Proper management of these injuries will ensure good healing and prevent late deformities. When loss occurs it is challenging to reconstruct which can be done by grafts or microsurgical reconstruction to restore aesthetic appearance of fingers.
Bainite orientation in plastically deformed austenite
Klobčar, Damjan; Shirzadi, A. A.; Abreu, H.; Pocock, L.; Withers, P.J.; Bhadeshia, Harshad Kumar Dharamshi Hansraj
2015-01-01
Experiments have been conducted to see whether specific crystallographic variants of bainite form in polycrystalline steel when transformation occurs from plastically deformed austenite which is otherwise free from externally applied stress. It is demonstrated by studying both overall and microtexture that there is no perceptible variant selection as bainite forms. Indeed, the texture is found to weaken on transformation.
Getting inflationary models using the deformation method
Rodrigues, Jamilton
2014-01-01
We show as the dynamics for the inflaton, under slow-roll regime, can be treated in a other dynamics, following the deformation procedure. In a direct way we present a relationship between two slow-roll inflationary potentials, and we apply this framework to show how to construct an eternal inflation from chaotic inflation, or even, a natural inflation from hilltop inflation, easily.
ELASTIC DEFORMATION ANALYSIS OF MULTILA YERED STRANDS
Institute of Scientific and Technical Information of China (English)
王世文; 冯继玲; 杨兆建; 连香姣
1999-01-01
This paper describes a general model for the mechanical behavior studying of general wire rope strand. An exact solution of the deformation characteristics was given when the strands is under tensile and torsional loads. The theoretical results are useful in evaluating the extensional and torsional moduli of rigidity for the strands. Finally, a simple design criterion is established for the nonrotating ropes.
Positivity in Rieffel's strict deformation quantization
Waldmann, Stefan
2009-01-01
We review a recent result on Rieffel's deformation quantization by actions of R^d: it is shown that for every state omega_0 of the undeformed C*-algebra A_0 there is a continuous section of states omega(hbar) through omega_0. We outline the physical interpretation in terms of quantization.
Tidal deformations of a spinning compact object
Pani, Paolo; Gualtieri, Leonardo; Maselli, Andrea; Ferrari, Valeria
2015-07-01
The deformability of a compact object induced by a perturbing tidal field is encoded in the tidal Love numbers, which depend sensibly on the object's internal structure. These numbers are known only for static, spherically-symmetric objects. As a first step to compute the tidal Love numbers of a spinning compact star, here we extend powerful perturbative techniques to compute the exterior geometry of a spinning object distorted by an axisymmetric tidal field to second order in the angular momentum. The spin of the object introduces couplings between electric and magnetic deformations and new classes of induced Love numbers emerge. For example, a spinning object immersed in a quadrupolar, electric tidal field can acquire some induced mass, spin, quadrupole, octupole and hexadecapole moments to second order in the spin. The deformations are encoded in a set of inhomogeneous differential equations which, remarkably, can be solved analytically in vacuum. We discuss certain subtleties in defining the tidal Love numbers in general relativity, which are due to the difficulty in separating the tidal field from the linear response of the object in the solution, even in the static case. By extending the standard procedure to identify the linear response in the static case, we prove analytically that the Love numbers of a Kerr black hole remain zero to second order in the spin. As a by-product, we provide the explicit form for a slowly-rotating, tidally-deformed Kerr black hole to quadratic order in the spin, and discuss its geodesic and geometrical properties.
Experimental deformation of polyphase rock analogues
Bons, P.D.
1993-01-01
This thesis presents an investigation into the mechanical properties of ductile polyphase materials, which were studied by a number of different techniques. The first approach was to do creep tests and transparent deformation cell experiments with two-phase composites of organic crystalline rock-ana
All Madelung deformities are not endocrine
Directory of Open Access Journals (Sweden)
Ajay Kumar
2013-01-01
Full Text Available Madelung deformity is a rare inherited disorder associated with endocrine disorders like Turner′s syndrome, pseudohypoparathyroidism, but can be seen with short stature homeobox deficiency conditions such as Leri-Weill dyschondrosteosis (LWD and Langers mesomelic dysplasia. It has also been reported following trauma to the distal radius epiphysis neoplasia mucopolysaccharidosis (MPS and achondroplasia. Madelung deformity is an abnormality of distal radial epiphysis where in progressive ulnar and volar tilt of the articular surface occurring in association with distal subluxation of ulna. A 13-year-old girl was referred to us for evaluation of bilateral deformity of wrist and short stature. There was ulnar deviation and dorsal tilt of bilateral hands without history of pain to the joint trauma and family history of similar illness. On X-ray, wrist showed malformed distal radial epiphysis with dorsal and ulnar shift and with increased length of phalanges suggestive of Madelung deformity. X-ray spine was normal. Ultrasound abdomen showed normal uterus and ovary and her follicle stimulating hormone. Luteinizing hormone was normal and so was urine MPS screening. Based on the above points the diagnosis of LWD was made.
Deformation of vortex patches by boundaries
Crosby, A; Morrison, P J
2013-01-01
The deformation of two-dimensional vortex patches in the vicinity of fluid boundaries is investigated. The presence of a boundary causes an initially circular patch of uniform vorticity to deform. Sufficiently far away from the boundary, the deformed shape is well approximated by an ellipse. This leading order elliptical deformation is investigated via the elliptic moment model of Melander, Zabusky & Styczek [M. V. Melander, N. J. Zabusky & A. S. Styczek, J. Fluid. Mech., 167, 95 (1986)]. When the boundary is straight, the centre of the elliptic patch remains at a constant distance from the boundary, and the motion is integrable. Furthermore, since the straining flow acting on the patch is constant in time, the problem is that of an elliptic vortex patch in constant strain, which was analysed by Kida [S. Kida, J. Phys. Soc. Japan, 50, 3517 (1981)]. For more complicated boundary shapes, such as a square corner, the motion is no longer integrable. Instead, there is an adiabatic invariant for the motion....
Shear deformation in thick auxetic plates
International Nuclear Information System (INIS)
This paper aims to understand the effect of auxeticity on shear deformation in thick plates. Three models for the shear correction factor of plates as a function of Poisson’s ratio were proposed: an analytical model, a cubic fit model and a modified model. Of these three, the cubic fit model exhibits the best accuracy over the entire range of Poisson’s ratio from −1 to 0.5. The extent of shear deformation is herein investigated using the example of uniformly loaded circular plates. It was found that the maximum deformation of such plates based on Mindlin theory approximates to those according to Kirchhoff theory when the Poisson’s ratio of the plate material is highly negative. When the Poisson’s ratio of the plate material is −1 and the edge of the plate is simply supported, the calculation of the maximum deflection by Mindlin theory simplifies into that by Kirchhoff theory. These results suggest that auxeticity reduces shear deformation in thick plates, permitting the use of classical plate theory for thick plates only if the plate material is highly auxetic. (paper)
Adaptive Method Using Controlled Grid Deformation
Directory of Open Access Journals (Sweden)
Florin FRUNZULICA
2011-09-01
Full Text Available The paper presents an adaptive method using the controlled grid deformation over an elastic, isotropic and continuous domain. The adaptive process is controlled with the principal strains and principal strain directions and uses the finite elements method. Numerical results are presented for several test cases.
What is "stationary" deformation of pure Cu?
Czech Academy of Sciences Publication Activity Database
Blum, W.; Dvořák, Jiří; Král, Petr; Eisenlohr, P.; Sklenička, Václav
2014-01-01
Roč. 49, č. 8 (2014), s. 2987-2997. ISSN 0022-2461 R&D Projects: GA ČR(CZ) GAP108/11/2260 Institutional support: RVO:68081723 Keywords : creep * Cu * recrystallization * stationary deformation resistances Subject RIV: JJ - Other Materials Impact factor: 2.371, year: 2014
Intraplate rotational deformation induced by faults
Dembo, Neta; Hamiel, Yariv; Granot, Roi
2015-11-01
Vertical axis rotations provide important constraints on the tectonic history of plate boundaries. Geodetic measurements can be used to calculate interseismic rotations, whereas paleomagnetic remanence directions provide constraints on the long-term rotations accumulated over geological timescales. Here we present a new mechanical modeling approach that links between intraplate deformational patterns of these timescales. We construct mechanical models of active faults at their locked state to simulate the presumed to be elastic interseismic deformation rate observed by GPS measurements. We then apply a slip to the faults above the locking depth to simulate the long-term deformation of the crust from which we derive the accumulated rotations. We test this approach in northern Israel along the Dead Sea Fault and Carmel-Gilboa fault system. We use 12 years of interseismic GPS measurements to constrain a slip model of the major faults found in this region. Next, we compare the modeled rotations against long-term rotations determined based on new primary magnetic remanence directions from 29 sites with known age. The distributional pattern of site mean declinations is in general agreement with the vertical axis rotations predicted by the mechanical model, both showing anomalously high rotations near fault tips and bending points. Overall, the results from northern Israel validate the effectiveness of our approach and indicate that rotations induced by motion along faults may act in parallel (or alone) to rigid block rotations. Finally, the new suggested method unravels important insights on the evolution (timing, magnitude, and style) of deformation along major faults.
Permanent Deformation of Highway Subgrade Soils
Institute of Scientific and Technical Information of China (English)
无
1999-01-01
Based on a comprehensive review of the literature and preliminary testing performed on a subgrade soil, a testing methodology for repeated load testing was established. This testing protocol was verified using data from subgrade soil. The successful application of this testing protocol on the two subgrade soils proves that it can provide consistent, reliable results. A power model was used to fit the accumulated axial strain over load repetitions with the first hundred cycles excluded from the data set. A number of factors influencing the accumulation of permanent deformation were investigated. The results indicate that confining pressure, load frequency and density are relatively minor contributors to deformation accumulation. Moisture content, deviator stress and first cycle freeze-thaw are major factors governing permanent deformation. The effects of stress history resulting from staged loading are dependent upon the level of applied deviator stress. The interpretation of the rich and consistent deformation data derived from this testing protocol provide valuable insights for transportation engineers relative to the design, construction, operation and maintenance strategy of highway subgrades as well as railway roadbeds.
Hot deformation behavior of 2060 alloy
International Nuclear Information System (INIS)
The hot deformation behavior of 2060 alloy has been studied using thermal simulation test, EBSD technique and transmission electron microscopy. The flow stress could be described by a Zener-Hollomon parameter in hyperbolic sine function with the hot deformation activation energy of 205 kJ/mol. Dynamic recovery is the main dynamic soften mechanism of 2060 alloy. The relative volume fraction of subgrains increases from about 30% to 90% as the temperature rises from 350 °C to 400 °C. When the temperature is higher than 400 °C, both the relative volume fraction of the deformed grains and subgrains remain steady. The processing maps are similar in the strain ranging from 0.1 to 0.5, and the unsafe domains increase with the increase of strain. The optimum hot-working condition for 2060 alloy is 380–500 °C and 0.01–3 s−1. - Highlights: • EBSD technique has been used to show the misorientations between neighboring grains. • The volume fraction of subgrains ranges from about 30% at 350 °C to 90% at 400 °C. • When T > 400 °C, volume fraction of deformed grains and subgrains keep unchangeable. • The unsafe domains increase with the increase of strain
Operator Deformations in Quantum Measurement Theory
Andersson, Andreas
2013-01-01
We describe rigorous quantum measurement theory in the Heisenberg picture by applying operator deformation techniques previously used in noncommutative quantum field theory. This enables the conventional observables (represented by unbounded operators) to play a role also in the more general setting.
Superplastic deformation of in situ synthesized TiC/7715D matrix composite
International Nuclear Information System (INIS)
The in situ synthesized TiC/7715D titanium matrix composite has been prepared and its superplasticity has been studied. A maximum elongation of 802% was obtained and different types of true strain-true stress curves were observed. The superplastic average activation energies involved were calculated as 366 and 625 kJ/mol, indicates that the deformation mechanism attributes to mainly dynamic recovery (DR) concurrent with grain boundary sliding (GBS)/grain coarsening (Growth) controlled by grain boundary diffusion and dynamically recrystallization (DRX) predominant concurrent with GBS/Growth controlled by lattice diffusion, respectively. They were verified by microstructures observed by optical microscopy (OM) and transmission electron microscopy (TEM).
DEFF Research Database (Denmark)
Jakobsen, Bo
2006-01-01
The main goal of the study presented in this thesis was to perform in-situ investigations on deformation structures in plastically deformed polycrystalline copper at low degrees of tensile deformation (<5%). Copper is taken as a model system for cell forming pure fcc metals. Anovel synchrotron......-radiation based technique High Angular Resolution 3DXRD has been developed at the 1-ID beam-line at the Advanced Photon Source. The technique extents the 3DXRD approach, to 3D reciprocal space mapping with a resolution of ≈ 1 · 10−3Å−1 and allows for in-situmapping of reflections from deeply-embedded individual...... width of the peaks, and spatial scanning experiments it is concluded that the individual peaks arise from individual dislocation-free regions (the subgrains) in the dislocation structure. The cloud is attributed to the dislocation rich walls. Samples deformed to 2% tensile strain were investigated under...
High temperature deformation behavior of a fine-grained tetragonal zirconia
International Nuclear Information System (INIS)
The stress exponent, n, defined in the following creep equation has often been regarded as a primary parameter to characterize superplastic deformation in fine-grained tetragonal zirconia containing 2.5 approximately 4 mol% yttria (Y-TZP): varepsilon = Aσn/dp where varepsilon is the strain rate, σ is the stress, d is the grain size, n is the stress exponent, p is the grain size exponent and A is a material constant. Recent studies have noted that the stress exponents of high-purity Y-TZP can be divided into two categories: n approximately 3 at low stresses and n approximately 2 at high stresses, where the stress dividing the deformation regions depends on both temperature and grain size. To argue the origins of such regions and relating mechanisms, however, some additional examination seems to be necessary for confirming that the regions characterized with n approximately 2 and approximately 3 are the genuine ones. This is because experimental limitations have tended to prevent the examination of deformation behavior by Eq. (1) in a strict sense. For example, the n-values have been derived from the overall strain rates that may indispensably include the effects of deformation around the grips of tensile specimens or those of constrained deformation near both sides of compression specimens. Furthermore, the data were obtained under an assumption that the effects of grain growth on the strain rate is negligible in Y-TZP. There seems to be rather little assurance, however, that these situations did not affect the evaluation of the stress exponent. From this point of view, the present study was conducted (1) to examine the effects of grain growth and some other experimental factors on creep behavior and (2) to evaluate the stress exponent from creep strain-rate curves corrected for both instantaneous stress and strain in a high purity Y-TZP
Molecular pathology of vertebral deformities in hyperthermic Atlantic salmon (Salmo salar
Directory of Open Access Journals (Sweden)
Hjelde Kirsti
2010-07-01
Full Text Available Abstract Background Hyperthermia has been shown in a number of organisms to induce developmental defects as a result of changes in cell proliferation, differentiation and gene expression. In spite of this, salmon aquaculture commonly uses high water temperature to speed up developmental rate in intensive production systems, resulting in an increased frequency of skeletal deformities. In order to study the molecular pathology of vertebral deformities, Atlantic salmon was subjected to hyperthermic conditions from fertilization until after the juvenile stage. Results Fish exposed to the high temperature regime showed a markedly higher growth rate and a significant higher percentage of deformities in the spinal column than fish reared at low temperatures. By analyzing phenotypically normal spinal columns from the two temperature regimes, we found that the increased risk of developing vertebral deformities was linked to an altered gene transcription. In particular, down-regulation of extracellular matrix (ECM genes such as col1a1, osteocalcin, osteonectin and decorin, indicated that maturation and mineralization of osteoblasts were restrained. Moreover, histological staining and in situ hybridization visualized areas with distorted chondrocytes and an increased population of hypertrophic cells. These findings were further confirmed by an up-regulation of mef2c and col10a, genes involved in chondrocyte hypertrophy. Conclusion The presented data strongly indicates that temperature induced fast growth is severely affecting gene transcription in osteoblasts and chondrocytes; hence change in the vertebral tissue structure and composition. A disrupted bone and cartilage production was detected, which most likely is involved in the higher rate of deformities developed in the high intensive group. Our results are of basic interest for bone metabolism and contribute to the understanding of the mechanisms involved in development of temperature induced
J. Blachowski; Milczarek, W.; P. Stefaniak
2014-01-01
The paper presents the concept of the deformation information system (DIS) to support and facilitate studies of mining-ground deformations. The proposed modular structure of the system includes data collection and data visualisation components, as well as spatial data mining, modelling and classification modules. In addition, the system integrates interactive three-dimensional models of the mines and local geology. The system is used to calculate various parameters character...
J. B. Blachowski; Milczarek, W.; P. Stefaniak
2013-01-01
The paper presents the concept of the Deformation Information System (DIS) to support and facilitate studies of mining ground deformations. The proposed modular structure of the system includes data collection and data visualisation components, as well as spatial data mining, modelling and classification modules. In addition, the system integrates interactive three-dimensional models of the mines and local geology. The system is used to calculate various parameters character...
A Two Stage CVT / Eikonal Convection Mesh Deformation Approach for Large Nodal Deformations
Schmidt, Stephan
2014-01-01
A two step mesh deformation approach for large nodal deformations, typically arising from non-parametric shape optimization, fluid-structure interaction or computer graphics, is considered. Two major difficulties, collapsed cells and an undesirable parameterization, are overcome by considering a special form of ray tracing paired with a centroid Voronoi reparameterization. The ray direction is computed by solving an Eikonal equation. With respect to the Hadamard form of the shape derivative, ...
Van Dam; Diepen, van, MJ; Huygen, J.
2003-01-01
SWAP contains three crop growth routines: a simple model, a detailed model (WOFOST), and the same model attuned to simulate grass growth. The simple model describes crop development, independent of external stress factors. The main function is to provide proper upper boundary conditions for soil water movement
... erythroplakia and also may become cancer over time. Oral cancer People who use tobacco, alcohol, or both are at much greater risk ( ... causes of noncancerous growths. Use of alcohol and tobacco is a risk factor for oral cancer. Because cancerous growths are difficult to recognize by ...
Eren, Yasar
2001-10-01
Low-grade metamorphic rocks of Paleozoic-Mesozoic age to the north of Konya, consist of two different groups. The Silurian-Lower Permian Sizma Group is composed of reefal complex metacarbonates at the base, and flyschoid metaclastics at the top. Metaigneous rocks of various compositions occur as dykes, sills, and lava flows within this group. The ?Upper Permian-Mesozoic age Ardicli Group unconformably overlies the Sizma Group and is composed of, from bottom to top, coarse metaclastics, a metaclastic-metacarbonate alternation, a thick sequence of metacarbonate, and alternating units of metachert, metacarbonates and metaclastics. Although pre-Alpine overthrusts can be recognized in the Sizma Group, intense Alpine deformation has overprinted and obliterated earlier structures. Both the Sizma and Ardicli Groups were deformed, and metamorphosed during the Alpine orogeny. Within the study area evidence for four phases of deformation and folding is found. The first phase of deformation resulted in the major Ertugrul Syncline, overturned tight to isoclinal and minor folding, and penetrative axial planar cleavage developed during the Alpine crustal shortening at the peak of metamorphism. Depending on rock type, syntectonic crystallization, rotation, and flattening of grains and pressure solution were the main deformation mechanisms. During the F 2-phase, continued crustal shortening produced coaxial Type-3 refolded folds, which can generally be observed in outcrop with associated crenulation cleavage (S 2). Refolding of earlier folds by the noncoaxial F 3-folding event generated Type-2 interference patterns and the major Meydan Synform which is the largest map-scale structure within the study area. Phase 3 structures also include crenulation cleavage (S 3) and conjugate kink folds. Further shortening during phase 4 deformation also resulted in crenulation cleavage and conjugate kink folds. According to thin section observations, phases 2-4 crenulation cleavages are mainly
Kerr black hole in canonically deformed space-time
Daszkiewicz, Marcin
2014-01-01
We investigate the Kerr black hole defined on canonically deformed space-time. Particulary, we find the corresponding event horizon, the ergosphere, the temperature and the entropy of such deformed object.
Deformation behaviour of cryo-drawn CuAl-wires
Energy Technology Data Exchange (ETDEWEB)
Kauffmann, Alexander; Song, Yin; Marr, Tom; Eckert, Juergen; Schultz, Ludwig [IFW Dresden, P.O. Box 270116, 01171 Dresden (Germany); TU Dresden, Institute of Materials Science, 01062 Dresden (Germany); Freudenberger, Jens [IFW Dresden, P.O. Box 270116, 01171 Dresden (Germany); Sarma, Vadlamani Subramanya [Dept. Metallurgical and Materials Engineering, IIT Madras, Chennai 600036 (India)
2011-07-01
The effect of temperature on the active deformation mechanism is studied. For this purpose cryogenic drawing of several CuAl alloys was performed. Hence, a solid lubrification is needed which remains operating at cryogenic temperatures. We present a comparison of several solid lubricants for the deformation of two Copper alloys. The comparison cryogenic temperature deformation of several CuAl alloys with conventionally drawn wires shows that the strengthening of these alloys during the deformation process is significantly affected by their stacking fault energy. The deformation at cryogenic temperature is most effective at intermediate stacking fault energies. This is interpreted in terms of a changing deformation mechanism from dislocation slip to deformation twinning. The analysis of the microstructure during the deformation process strengthens these assumptions.
Island of Stability for Consistent Deformations of Einstein's Gravity
DEFF Research Database (Denmark)
Dietrich, Dennis D.; Berkhahn, Felix; Hofmann, Stefan;
2012-01-01
We construct deformations of general relativity that are consistent and phenomenologically viable, since they respect, in particular, cosmological backgrounds. These deformations have unique symmetries in accordance with their Minkowski cousins (Fierz-Pauli theory for massive gravitons) and incor...
Free-Form Deformation with Rational DMS-Spline Volumes
Institute of Scientific and Technical Information of China (English)
Gang Xu; Guo-Zhao Wang; Xiao-Diao Chen
2008-01-01
In this paper, we propose a novel free-form deformation (FFD) technique, RDMS-FFD (Rational DMS-FFD),based on rational DMS-spline volumes. RDMS-FFD inherits some good properties of rational DMS-spline volumes and combines more deformation techniques than previous FFD methods in a consistent framework, such as local deformation,control lattice of arbitrary topology, smooth deformation, multiresolution deformation and direct manipulation of deforma-tion. We first introduce the rational DMS-spline volume by directly generalizing the previous results related to DMS-splies.How to generate a tetrahedral domain that approximates the shape of the object to be deformed is also introduced in this paper. Unlike the traditional FFD techniques, we manipulate the vertices of the tetrahedral domain to achieve deformation results. Our system demonstrates that RDMS-FFD is powerful and intuitive in geometric modeling.
Ongoing deformation of Antarctica following recent Great Earthquakes
King, Matt A.; Santamaría-Gómez, Alvaro
2016-03-01
Antarctica's secular motion is thought to be almost everywhere governed by horizontal rigid plate rotation plus three-dimensional deformations due to past and present changes in ice ocean loading, known as glacial isostatic adjustment (GIA). We use geodetic data to investigate deformation following the 1998 M ~8.2 Antarctic intraplate Earthquake and show sustained three-dimensional deformation along East Antarctica's coastline, 600 km from the rupture location. Using a model of viscoelastic deformation, we are able to match observed northward velocity changes, and either east or height, but not all three directions simultaneously, apparently partly due to lateral variations in mantle rheology. Our modeling predicts that much of Antarctica may still be deforming, with further deformation possible from the 2004 M 8 Macquarie Ridge Earthquake. This previously unconsidered mode of Antarctic deformation affects geodetic estimates of plate motion and GIA; its viscous nature raises the prospect of further present-day deformation due to earlier Great Earthquakes.
Magnetic Barkhausen emission in lightly deformed AISI 1070 steel
Energy Technology Data Exchange (ETDEWEB)
Capo Sanchez, J., E-mail: jcapo@cnt.uo.edu.cu [Departamento de Fisica, Facultad de Ciencias Naturales, Universidad de Oriente, Av. Patricio Lumumba s/n, 90500 Santiago de Cuba (Cuba); Campos, M.F. de [EEIMVR-Universidade Federal Fluminense, Av. dos Trabalhadores 420, Vila Santa Cecilia, 27255-125 Volta Redonda, RJ (Brazil); Padovese, L.R. [Departamento de Engenharia Mecanica, Escola Politecnica, Universidade de Sao Paulo, Av. Prof. Mello Moraes, 2231, 05508-900 Sao Paulo (Brazil)
2012-01-15
The Magnetic Barkhausen Noise (MBN) technique can evaluate both micro- and macro-residual stresses, and provides indication about the relevance of contribution of these different stress components. MBN measurements were performed in AISI 1070 steel sheet samples, where different strains were applied. The Barkhausen emission is also analyzed when two different sheets, deformed and non-deformed, are evaluated together. This study is useful to understand the effect of a deformed region near the surface on MBN. The low permeability of the deformed region affects MBN, and if the deformed region is below the surface the magnetic Barkhausen signal increases. - Highlights: > Evaluated residual stresses by the magnetic Barkhausen technique. > Indication about the relevance of micro-and macro-stress components. > Magnetic Barkhausen measurements were carried out in AISI 1070 steel sheet samples. > Two different sheets, deformed and non-deformed, are evaluated together. > Magnetic Barkhausen signal increases when deformed region is below the surface.
A perfect-fluid spacetime for a slightly deformed mass
Abishev, Medeu; Quevedo, Hernando; Toktarbay, Saken
2015-01-01
We present approximate exterior and interior solutions of Einstein's equations which describe the gravitational field of a static deformed mass distribution. The deformation of the source is taken into account up to the first order in the quadrupole.
ANOPHTHALMIA: A NON-HERITABLE EYE DEFORMITY IN Oreochromis mossambicus
D. Tave; T. Handwerker
1998-01-01
Seven male Oreochromis mossambicus with anophthalmia were found in a hatchery population. The deformity was not observed in either the Fl or F2 generations; consequently, it was a non-heritable congenital deformity.
Deformation around basin scale normal faults
International Nuclear Information System (INIS)
Faults in the earth crust occur within large range of scales from microscale over mesoscopic to large basin scale faults. Frequently deformation associated with faulting is not only limited to the fault plane alone, but rather forms a combination with continuous near field deformation in the wall rock, a phenomenon that is generally called fault drag. The correct interpretation and recognition of fault drag is fundamental for the reconstruction of the fault history and determination of fault kinematics, as well as prediction in areas of limited exposure or beyond comprehensive seismic resolution. Based on fault analyses derived from 3D visualization of natural examples of fault drag, the importance of fault geometry for the deformation of marker horizons around faults is investigated. The complex 3D structural models presented here are based on a combination of geophysical datasets and geological fieldwork. On an outcrop scale example of fault drag in the hanging wall of a normal fault, located at St. Margarethen, Burgenland, Austria, data from Ground Penetrating Radar (GPR) measurements, detailed mapping and terrestrial laser scanning were used to construct a high-resolution structural model of the fault plane, the deformed marker horizons and associated secondary faults. In order to obtain geometrical information about the largely unexposed master fault surface, a standard listric balancing dip domain technique was employed. The results indicate that for this normal fault a listric shape can be excluded, as the constructed fault has a geologically meaningless shape cutting upsection into the sedimentary strata. This kinematic modeling result is additionally supported by the observation of deformed horizons in the footwall of the structure. Alternatively, a planar fault model with reverse drag of markers in the hanging wall and footwall is proposed. Deformation around basin scale normal faults. A second part of this thesis investigates a large scale normal fault
Macro deformation twins in single-crystal aluminum
Zhao, F.; Wang, L.; Fan, D.; B. X. Bie; Zhou, X. M.; Suo, T.; Y. L. Li; Chen, M. W.; Liu, C; Qi, M. L.; Zhu, M. H.; Luo, S. N.
2015-01-01
Deformation twinning in pure aluminum has been considered to be a unique property of nanostructured aluminum. A lingering mystery is whether deformation twinning occurs in coarse-grained or single-crystal aluminum, at scales beyond nanotwins. Here, we present the first experimental demonstration of macro deformation twins in single-crystal aluminum formed under ultrahigh strain-rate ($\\sim$10$^6$ s$^{-1}$), large shear strain (200$\\%$) via dynamic equal channel angular pressing. Deformation t...
q-deformed superconformal algebra on quantum superspace
Kobayashi, Tatsuo; Uematsu, Tsuneo
1993-01-01
A quantum deformation of 4-dimensional superconformal algebra realized on quantum superspace is investigated. We study the differential calculus and the action of the quantum generators corresponding to $sl_q(1|4)$ which act on the quantum superspace. We derive deformed $su(1|2,2)$ algebras from the deformed $sl(1|4)$ algebra. Through a contraction procedure we obtain a deformed super-Poincar{\\'e} algebra.
Calculation fundamentals for sensitive elements of acoustic transformers of deformation
International Nuclear Information System (INIS)
Acoustic method of deformation measurement is considered, and the foundations of the calculation of sensitive elements of acoustic transformers of deformations are given. Acoustic method gives the possibility to measure deformations in almost inaccessible places, for example, in a reactor core. A sensible element transforming deformation into acoustic signal is the constriction of waveguide. Working characteristics and shapes of sensitive elements of an acoustic transformer of linear and angular displacements are presented
Analysis of Ground Deformations Induced by Tunnel Excavation
Mingli Huang; Jia Guo; Zhongsheng Tan
2012-01-01
In this study, we analyzing the ground deformation response in water-bearing sandstone ground caused by tunnel excavation. Moreover, based on the field monitoring data of Xiang-an subaqueous tunnel in Xiamen, taking a deep research on ground deformations caused by large cross section tunnel excavation. From our research results, during tunnel excavation surface settlement and extensometer settlement may be divided into four stages: slight deformation stage, rapid deformation stage, stable sta...
Implicit Boundary Control of Vector Field Based Shape Deformations
von Funck, Wolfram; Theisel, Holger; Seidel, Hans-Peter
2007-01-01
We present a shape deformation approach which preserves volume, prevents self-intersections and allows for exact control of the deformation impact. The volume preservation and prevention of selfintersections are achieved by utilizing the method of Vector Field Based Shape Deformations. This method produces physically plausible deformations efficiently by integrating formally constructed divergence-free vector fields, where the region of influence is described by implicitly ...
Discrete element modelling of permanent pavement deformation in granular materials
Cai, Wei
2015-01-01
The permanent deformation of a pavement due to vehicle load is one of the important factors affecting the design life as well as the maintenance cost of a pavement. For the purpose of obtaining a cost-effective design, it is advisable to predict the traffic-loadinduced permanent pavement deformation. The permanent deformation in pavements (i.e. rutting) can be classified into three categories, including the wearing of the asphalt layers, compaction, and shear deformations. In the present stud...
Twinning in copper deformed at high strain rates
Indian Academy of Sciences (India)
S Cronje; R E Kroon; W D Roos; J H Neethling
2013-02-01
Copper samples having varying microstructures were deformed at high strain rates using a split-Hopkinson pressure bar. Transmission electron microscopy results show deformation twins present in samples that were both annealed and strained, whereas samples that were annealed and left unstrained, as well as samples that were unannealed and strained, are devoid of these twins. These deformation twins occurred at deformation conditions less extreme than previously predicted.
Deformation-induced microstructures: analysis and relation to properties
International Nuclear Information System (INIS)
The formation of microstructures is a unifying theme in the wide spectrum of materials behaviour associated with plastic deformation. Thus microstructures are generated during monotonic and cyclic deformation at low and high temperatures as well as during creep. Microstructures forming locally at crack fronts play critical roles in fatigue and fracture. It is becoming increasingly clear that deformation-induced microstructures are far more diversified than previously assumed. These deformation-induced microstructures define the theme of the present symposium. (LN)
Measurement and analysis of brain deformation during neurosurgery
Hartkens, T.; Hill, D. L.; Castellano-Smith, A. D.; Hawkes, D. J.; Maurer, C. R.; Jr, M.; A J, H.; W A, L.; H., T.; C, L.
2003-01-01
Recent studies have shown that the surface of the brain is deformed by up to 20 mm after the skull is opened during neurosurgery, which could lead to substantial error in commercial image-guided surgery systems. We quantitatively analyze the intraoperative brain deformation of 24 subjects to investigate whether simple rules can describe or predict the deformation. Interventional magnetic resonance images acquired at the start and end of the procedure are registered nonrigidly to obtain deform...
International Nuclear Information System (INIS)
The incorporation of daily images into the radiotherapy process leads to adaptive radiation therapy (ART), in which the treatment is evaluated periodically and the plan is adaptively modified for the remaining course of radiotherapy. Deformable registration between the planning image and the daily images is a key component of ART. In this paper, we report our researches on deformable registration between the planning kVCT and the daily MVCT image sets. The method is based on a fast intensity-based free-form deformable registration technique. Considering the noise and contrast resolution differences between the kVCT and the MVCT, an 'edge-preserving smoothing' is applied to the MVCT image prior to the deformable registration process. We retrospectively studied daily MVCT images from commercial TomoTherapy machines from different clinical centers. The data set includes five head-neck cases, one pelvis case, two lung cases and one prostate case. Each case has one kVCT image and 20-40 MVCT images. We registered the MVCT images with their corresponding kVCT image. The similarity measures and visual inspections of contour matches by physicians validated this technique. The applications of deformable registration in ART, including 'deformable dose accumulation', 'automatic re-contouring' and 'tumour growth/regression evaluation' throughout the course of radiotherapy are also studied
Some observations on deformation-related discontinuous precipitation in an Al-14.6at.%Zn alloy
International Nuclear Information System (INIS)
Research highlights: → Effects of prior strain on discontinuous precipitation (DP) in an Al-Zn alloy. → DP in recrystallized grains enables formation of equiaxed dual-phase nanostructures. → Deformation bands and dislocation cell walls are potential nucleation sites for DP. → Deformation bands contribute to the development of faceted DP cell fronts. - Abstract: The discontinuous precipitation (DP) in a supersaturated Al-14.6at.%Zn alloy in relation to different forms of deformation structures has been investigated with optical and electron microscopy. It has been found that intense surface scribing, followed by short-term ageing at 65 deg. C, resulted in a recrystallized duplex structure with nanoscale equiaxed β-Zn particles and α-Al grains. In the absence of recrystallization and shear banding, moderate surface grinding increased the transformation kinetics of DP on the alloy surface by an order of magnitude compared with that of the undeformed counterpart. The enhanced transformation kinetics is attributed to intragranular nucleation and growth of DP colonies associated plausibly with dislocation cell wall structures induced by the surface strain. In contrast, bulk deformation by means of cold-rolling (13-66% reduction) and in situ stress-ageing (∼1% strain) both suppressed the development of DP in the alloy. The role of deformation bands as nucleation sites of DP and the driving force determining the development of DP colonies in deformed matrices are discussed.
Q-deformed algebras and many-body physics
International Nuclear Information System (INIS)
A review is presented of some applications of q-deformed algebras to many-body systems. The rotational and pairing nuclear problems will be discussed in the context of q-deformed algebras, before presenting a more microscopically based application of q-deformed concepts to many-fermion systems. (author). 30 refs., 5 figs
Plastic deformation of ultrafine-grained metallic materials
Kozlov, E. V.; Popova, N. A.; Koneva, N. A.
2015-04-01
The micromechanisms of plastic deformation of ultrafine-grained metallic materials are analyzed using copper, the nanostructure of which is produced by equal-channel angular pressing, as an example. Slip traces are studied at various deformation stages, and their parameters are estimated. The change in the granular structure during deformation has been studied.
Chapter 6. High temperature deformation of metals and alloys
International Nuclear Information System (INIS)
The mechanisms which characterize the high temperature deformation of metals and alloys are described: non-conservative motions of dislocations by emission and absorption of vacancies, decrease of grain boundary strength and intergranular sliding, dynamic recrystallization. These mechanisms explain the rearrangement of the removal of defects created during the deformation and enable an understanding of the high temperature plastic deformation
A fundamental discussion of what triggers localized deformation in geological materials
Peters, Max; Paesold, Martin; Poulet, Thomas; Herwegh, Marco; Regenauer-Lieb, Klaus; Veveakis, Manolis
2015-04-01
Discontinuous or localized structures are often marked by the transition from a homogeneously deforming into a highly localized mode. This transition has extensively been described in ductile shear zones, folding and pinch-and-swell boudinage, in natural examples, rock deformation experiments and numerical simulations, at various scales. It is conventionally assumed that ductile instabilities, which act as triggers for localized deformation, exclusively arise from structural heterogeneities, i.e. geometric interactions or material imperfections. However, Hansen et al. (2012) concluded from recent laboratory experiments that localized deformation might arise out of steady-state conditions, where the size of initial perturbations was either insufficiently large to trigger localization, or these heterogeneities were simply negligible at the scale of observation. We therefore propose the existence of a principal localization phenomenon, which is based on the material-specific rate-dependency of deformation at elevated temperatures. The concept of strain localization out of a mechanical steady state in a homogeneous material at a critical material parameter and/or deformation rate has previously been discussed for engineering materials (Gruntfest, 1963) and frictional faults (Veveakis et al., 2010). We expand this theory to visco-plastic carbonate rocks, considering deformation conditions and mechanisms encountered in naturally deformed rocks. In the numerical simulation, we implement a grain-size evolution based on the Paleowattmeter scaling relationship of Austin & Evans (2007), which takes both grain size sensitive (diffusion) and insensitive (dislocation) creep combined with grain growth into account (Herwegh et al., 2014). Based on constant strain rate simulations carried out under isothermal boundary conditions, we explore the parameter space in order to obtain the criteria for localization. We determine the criteria for the onset of localization, i.e. the
On the deformability of Heisenberg algebras
International Nuclear Information System (INIS)
Based on the vanishing of the second Hochschild cohomology group of the Weyl algebra it is shown that differential algebras coming from quantum groups do not provide a non-trivial deformation of quantum mechanics. For the case of a q-oscillator there exists a deforming map to the classical algebra. It is shown that the differential calculus on quantum planes with involution, i.e., if one works in position-momentum realization, can be mapped on a q-difference calculus on a commutative real space. Although this calculus leads to an interesting discretization it is proved that it can be realized by generators of the undeformed algebra and does not possess a proper group of global transformations. (orig.)
Tidal deformability of dark matter clumps
Mendes, Raissa F P
2016-01-01
We analyze the tidal deformability of a clump of dark matter particles, modelled by the collisionless Boltzmann equation. We adopt a wave-mechanical approach to the problem, in which the dynamical equations are approximated by a set of Schr\\"{o}dinger-Poisson equations, within the limit that the effective de Broglie wavelength is comparable to the spatial variation scale of the particle distribution. We argue that such a treatment allows for a smaller number of coupled differential equations and more accessible perturbative analyses, while keeping the description within the dynamical timescale relatively accurate. Moreover, it provides an approximate mapping between perturbed boson star configurations and dynamical dark matter clumps. We present an analysis of the tidal deformability of a minimally-coupled boson star to illustrate this (approximate) correspondence.
Processing magnesium alloys by severe plastic deformation
Figueiredo, Roberto B.; Aguilar, Maria Teresa P.; Cetlin, Paulo Roberto; Langdon, Terence G.
2014-08-01
The use of severe plastic deformation techniques for processing magnesium alloys has moved from the early difficulties of processing to a stage of tailoring the best properties of these materials. The present paper reviews processing, structure and mechanical properties characterization. It is shown that ultrafine-grained structures are obtained in magnesium alloys processed by multiple passes of Equal-Channel Angular Pressing at moderate temperatures. Ultrafine-grained structures are also obtained by room temperature processing by High- Pressure Torsion. The ultrafine-grained structures increase strength and introduce excellent superplastic capabilities in many magnesium alloys. Moreover, processing magnesium alloys by severe plastic deformation leads to the development of anisotropy in mechanical behavior.
Quark mass deformation of holographic massless QCD
International Nuclear Information System (INIS)
We propose several quark mass deformations of the holographic model of massless QCD using the D4/D8/D8-bar-brane configuration proposed by Sakai and Sugimoto. The deformations are based on introducing additional D4- or D6-branes away from the QCD D4-branes. The idea is similar to extended technicolor theories, where the chiral symmetry breaking by additional D-branes is mediated to QCD to induce non-zero quark masses. In the D-brane picture, as well as the holographic dual gravity description, the quark and the pion masses are generated by novel worldsheet instantons with finite area. We also derive the Gell-Mann-Oakes-Renner relation, and find the value of the chiral condensate in the Sakai-Sugimoto model. (author)
Octupole Deformed Nuclei in the Actinide Region
Thorsteinsen, T; Rubio barroso, B; Simpson, J; Gulda, K; Sanchez-vega, M; Cocks, J; Nybo, K; Garcia borge, M; Aas, A; Fogelberg, B; Honsi, J; Smith, G; Naumann, R; Grant, I
2002-01-01
The aim of the present study is to investigate the limits of the "island" of octupole deformation in the mass region A=225. It is of particular importance to demonstrate experimentally the sudden disappearance of the stable octupole deformation in the presence of a well developed quadrupole field. \\\\ \\\\In order to establish the upper border line the $\\beta$ -decay chains of $^{227}$Rn $\\rightarrow ^{227}$Fr $\\rightarrow ^{227}$Ra and $^{231}$Fr $\\rightarrow ^{231}$Ra $\\rightarrow ^{231}$Ac were studied at PSB-ISOLDE using advanced fast timing and $\\gamma$-ray spectroscopy techniques. The lifetimes of the excited states have been measured in the picosecond range using the time-delayed $\\beta\\gamma\\gamma$(t) method.
Theory of photoinduced deformation of molecular films
DEFF Research Database (Denmark)
Gaididei, Yuri B.; Christiansen, Peter Leth; Ramanujam, P.S.
2002-01-01
Azobenzene-containing polymers exhibit strong surface-relief features when irradiated with polarized light. Currently proposed theories do not explain all the observed features. Here we propose a theory based on elastic deformation of the polymer due to interaction between dipoles ordered through...... polarized light irradiation. The effects are due to the presence of a boundary layer. The observation of both wells and humps dependent on the architecture of the polymer can be explained with the present theory.......Azobenzene-containing polymers exhibit strong surface-relief features when irradiated with polarized light. Currently proposed theories do not explain all the observed features. Here we propose a theory based on elastic deformation of the polymer due to interaction between dipoles ordered through...
Accommodation processes during deformation of nanocrystalline palladium
International Nuclear Information System (INIS)
Atomistic simulations of uniaxial tensile and compressive straining of three-dimensional nanocrystalline palladium were performed at room temperature and different strain rates. Detailed analysis revealed that initial plastic deformation is due to grain boundary sliding accommodated by localized bending inside the grains and the formation of dislocation embryos. Intergranular cracking in the absence of dislocation activity was found at later stages of tensile straining. During compressive straining the sample shows a plastic response which is brought about mainly by intergranular accommodation processes. The contribution of extended partial dislocations emitted from the grain boundaries as well as full dislocations and twinning at later stages of deformation to the total strain was found to be insignificant.
Deformed Coherent State for Multiparticle Production Mechanism
Wang, W. Y.; Leong, Q.; Ng, W. K.; Dewanto, A.; Chan, A. H.; Oh, C. H.
2014-04-01
The deformation structure function describing the Generalised Multiplicities Distribution (GMD), Negative Binomial Distribution (NBD), Furry-Yule Distribution (FYD), and their corresponding deformed coherent states and second order correlation function g(2) are derived. A superposition model of the GMD and NBD states is then proposed as a general description of the mechanism that gives rise to the double NBD model first proposed by Giovannini. The model is applied to LHC multiplicity data at |η| ≤ 2.4 and 0.9, 2.36 and 7 TeV, from the CMS collaboration at CERN, and the second order correlation g(2) of the model is then compared with the normalised second factorial moment {F_2}/F_1^2 of the multiplicity.
Optical Coherence Tomography for Tracking Canvas Deformation
International Nuclear Information System (INIS)
Preliminary results of the application of optical coherence tomography (OCT), in particular in its spectral mode (SOCT), to tracking of deformations in paintings on canvas caused by periodical humidity changes are presented. The setup is able to monitor the position of a chosen point at the surface of a painting with micrometre precision, simultaneously in three dimensions, every 100 seconds. This allows recording of deformations associated with crack formation. For the particular painting model examined, it was shown that the surface moves in-plane towards the corner, and bulges outwards (Z-direction) in response to a rise in humidity. Subsequent to the first humidification/drying cycle, translation in the Z-direction is decreased, whilst in-plane translations increase somewhat. It was also shown that the response of the painting on canvas begins immediately on changing the relative humidity in the surroundings.
High-precision multicomponent borehole deformation monitoring
Gladwin, Michael T.
1984-12-01
An instrument capable of deep borehole measurement of vector plane strain to 0.3 nstrain and tilt to 1.0 nrad has been developed for deployment in crustal deformation and earthquake prediction studies. The instrument has been deployed in California where shear strains dominate the deformation. The 125-mm-diam package is grouted in 175-mm boreholes at depths of approximately 200 m. The wall thickness and the grout thickness are chosen to match instrument strength to expected rock parameters. The instrument is capable of flat response from dc to 10 Hz on any single channel. The electronics package is stable to three parts in 108 over the temperature range 10 to 45° C. Reliable shear strain data is available immediately on installation when simple volume strain meters show only bond curing effects or thermal recovery signals.
Entanglement entropy across a deformed sphere
Mezei, Márk
2014-01-01
I study the entanglement entropy (EE) across a deformed sphere in conformal field theories (CFTs). I show that the sphere (locally) minimizes the universal term in EE among all shapes. In arXiv:1407.7249 it was derived that the sphere is a local extremum, by showing that the contribution linear in the deformation parameter is absent. In this paper I demonstrate that the quadratic contribution is positive and is controlled by the coefficient of the stress tensor two point function, $C_T$. Such a minimization result contextualizes the fruitful relation between the EE of a sphere and the number of degrees of freedom in field theory. I work with CFTs with gravitational duals, where all higher curvature couplings are turned on. These couplings parametrize conformal structures in stress tensor $n$-point functions, hence I show the result for infinitely many CFT examples.
Extracting tissue deformation using Gabor filter banks
Montillo, Albert; Metaxas, Dimitris; Axel, Leon
2004-04-01
This paper presents a new approach for accurate extraction of tissue deformation imaged with tagged MR. Our method, based on banks of Gabor filters, adjusts (1) the aspect and (2) orientation of the filter"s envelope and adjusts (3) the radial frequency and (4) angle of the filter"s sinusoidal grating to extract information about the deformation of tissue. The method accurately extracts tag line spacing, orientation, displacement and effective contrast. Existing, non-adaptive methods often fail to recover useful displacement information in the proximity of tissue boundaries while our method works in the proximity of the boundaries. We also present an interpolation method to recover all tag information at a finer resolution than the filter bank parameters. Results are shown on simulated images of translating and contracting tissue.
Deformation Properties and Fatigue of Bituminous Mixtures
Directory of Open Access Journals (Sweden)
Frantisek Schlosser
2013-01-01
Full Text Available Deformation properties and fatigue performance are important characteristics of asphalt bound materials which are used for construction of pavement layers. Viscoelastic asphalt mixtures are better characterized via dynamic tests. This type of tests allows us to collate materials with regard to axle vibrations which lie usually in the range of 6 Hz–25 Hz for standard conditions. Asphalt modified for heat sensitivity in the range from −20°C to +60°C has significant impact on the overall characteristics of the mixture. Deformation properties are used as inputs for empirical mixture design, and fatigue performance of asphalt mixtures reflects the parameters of functional tests. Master curves convey properties of asphalt mixtures for various conditions and allow us to evaluate them without the need of time expensive testing.
Shell deformation studies using holographic interferometry
Parmerter, R. R.
1974-01-01
The buckling of shallow spherical shells under pressure has been the subject of many theoretical and experimental papers. Experimental data above the theoretical buckling load of Huang have given rise to speculation that shallow shell theory may not adequately predict the stability of nonsymmetric modes in higher-rise shells which are normally classified as shallow by the Reissner criterion. This article considers holographic interferometry as a noncontact, high-resolution method of measuring prebuckling deformations. Prebuckling deformations of a lambda = 9, h/b = 0.038 shell are Fourier-analyzed. Buckling is found to occur in an N = 5 mode as predicted by Huang's theory. The N = 4 mode was unusually stable, suggesting that even at this low value of h/b, stabilizing effects may be at work.
Nonlinear Elasticity in a Deforming Ambient Space
Yavari, Arash; Ozakin, Arkadas; Sadik, Souhayl
2016-07-01
In this paper, we formulate a nonlinear elasticity theory in which the ambient space is evolving. For a continuum moving in an evolving ambient space, we model time dependency of the metric by a time-dependent embedding of the ambient space in a larger manifold with a fixed background metric. We derive both the tangential and the normal governing equations. We then reduce the standard energy balance written in the larger ambient space to that in the evolving ambient space. We consider quasi-static deformations of the ambient space and show that a quasi-static deformation of the ambient space results in stresses, in general. We linearize the nonlinear theory about a reference motion and show that variation of the spatial metric corresponds to an effective field of body forces.
Thalidomide deformities and their nerve supply.
McCredie, J; North, K; De Iongh, R
1984-01-01
The aim of this study was to test the hypothesis that thalidomide acts upon the embryonic peripheral nervous system rather than upon mesenchyme. Pregnant rabbits were given oral thalidomide (150 mg/kg/day) on Days 7-11 of gestation. Fetuses were removed at laparotomy, under anaesthesia, on Day 29 of gestation. Seven fetuses with partial or total absence of the tibia, five treated fetuses without deformities, and four untreated controls were photographed, radiographed, killed and fixed for his...
Symmetric $q$-deformed KP hierarch
Tian, Kelei; He, Jingsong; Su, Yucai
2014-01-01
Based on the analytic property of the symmetric $q$-exponent $e_q(x)$, a new symmetric $q$-deformed Kadomtsev-Petviashvili ($q$-KP) hierarchy associated with the symmetric $q$-derivative operator $\\partial_q$ is constructed. Furthermore, the symmetric $q$-CKP hierarchy and symmetric $q$-BKP hierarchy are defined. Here we also investigate the additional symmetries of the symmetric $q$-KP hierarchy.
Deformation and failure behaviour of elbows
International Nuclear Information System (INIS)
In this paper, various experimental investigations of elbows under internal pressure and subjected to bending load are introduced. A brief description of the tests is followed by a presentation of the test results for the deformation behaviour of elbows and a comparison with theoretically determined predictions. The paper concludes with a description of the modes of failure of pipe elbows subjected to cyclic bending load. (orig.)
Tidal deformability of dark matter clumps
Mendes, Raissa F. P.; Yang, Huan
2016-01-01
We analyze the tidal deformability of a clump of dark matter particles, modelled by the collisionless Boltzmann equation. We adopt a wave-mechanical approach to the problem, in which the dynamical equations are approximated by a set of Schr\\"{o}dinger-Poisson equations, within the limit that the effective de Broglie wavelength is comparable to the spatial variation scale of the particle distribution. We argue that such a treatment allows for a smaller number of coupled differential equations ...
Configuration-dependent deformations in 171Re
International Nuclear Information System (INIS)
The level scheme of 75171Re96 has been studied using (heavy ion, xnyp) reactions. Rotational bands associated with the one- quasiproton Nilsson configurations 5/2+ [402], 1/2+ [411] and 9/2- [514] and the cross-shell orbitals from the h9/2 and i13/2 protons (nominally 1/2-[541] and 1/2+ [660]) have been identified. Less extensive results for 173Re have also been obtained. Differing (configuration-dependent) deformations are required to explain the frequencies and alignment gains in the neutron band-crossings. The relative differences are consistent with predicted deformation changes in the deformation-driving h9/2 and i13/2 (proton) orbitals. Signature splitting in the 9/2- [514] and 5/2+ [402] bands at low spin suggests some γ-deformation. Competing in-band and out-of-band E2 decays in the region of the real crossing between the 1/2+ [660] and 5/2+ [402] bands are explained through particle-rotor band-mixing calculations with the ad-hoc inclusion of ΔN=2 mixing. limited agreement between observed one-quasiparticle energies and predicted values underlines the limitation of currently accepted nuclear potentials in this region. Small alignment gains in the 5/2+ [402] and 1/2+ [411] bands, before the ΑΒ neutron alignment can be related to the low-spin anomaly in 172Os and explained using 3- band mixing. The absence of a similar effect in the 9/2- [514] band is discussed. 39 refs., 13 figs., 7 tabs
When Shape Matters: Deformations of Tiling Spaces
Clark, Alex; Sadun, Lorenzo
2003-01-01
We investigate the dynamics of tiling dynamical systems and their deformations. If two tiling systems have identical combinatorics, then the tiling spaces are homeomorphic, but their dynamical properties may differ. There is a natural map ${\\mathcal I}$ from the parameter space of possible shapes of tiles to $H^1$ of a model tiling space, with values in $\\R^d$. Two tiling spaces that have the same image under ${\\mathcal I}$ are mutually locally derivable (MLD). When the difference of the imag...
MR imaging in congenital lower limb deformities
Energy Technology Data Exchange (ETDEWEB)
Laor, T. [Dept. of Radiology, Children`s Hospital and Harvard Medical School, Boston, MA (United States); Jaramillo, D. [Dept. of Radiology, Children`s Hospital and Harvard Medical School, Boston, MA (United States); Hoffer, F.A. [Dept. of Radiology, Children`s Hospital and Harvard Medical School, Boston, MA (United States); Kasser, J.R. [Dept. of Orthopedics, Children`s Hospital and Harvard Medical School, Boston, MA (United States)
1996-06-01
Treatment for children with cogenital deformities of the lower extremities may vary, depending on the state of the unossified skeletal structures and surrounding soft tissues. The purpose of our study was to demonstrate the spectrum of the osteochondral and extrasosseous abnormalities as depicted with MR imaging. We retrospectively reviewed MR examinations of 13 limbs of ten children (aged 1 month-9 years, mean 2.1 years) with longitudinal and transverse deformities of the lower extremities. The lesions imaged were fibular hemimelia (n=5), tibial hemimelia (n=5), and congenital constriction bands (n=3). Each examination was assessed for abnormalities in the osteocartilaginous and extraosseous (articular or periarticular components such as ligaments, tendons, and menisci; the muscles and the arteries) structures. Abnormalities were seen in all patients. Osteocartilaginous abnormalities in the patients with longitudinal deformities included abnormal distal femoral epiphyses, abnormal proximal tribial physes, hypertrophied and dislocated proximal fibular epiphyses, unsuspected fibular and tibial remnants, and absence or coalition of the tarsal bones. No osteocartilaginous abnormalities were seen in the patients with congential constriction bands. Articular abormalities in patients with either form of hemimelia included absent cruciate ligaments and menisci, dislocated or absent cartilaginous patellae, absent patellar tendons, and abnormal collateral ligaments. All but one limb imaged had absent or attenuated muscle groups. Of the nine MR arteriograms performed at the level of the knee, eight were abnormal. The normal popliteal trifurcation was absent or in an abnormal location. We conclude that MR imaging of children with congenital lower extremity deformities shows many osteochondral and extraosseous abnormalities that are not depicted by conventional radiogrpahy. This information can help to plan early surgical intervention and prosthetic rehabilitation. (orig.)
The Minimal Geometric Deformation Approach Extended
Casadio, Roberto; da Rocha, Roldao
2015-01-01
The minimal geometric deformation approach was introduced in order to study the exterior space-time around spherically symmetric self-gravitating systems, like stars or similar astrophysical objects as well, in the Randall-Sundrum brane-world framework. A consistent extension of this approach is developed here, which contains modifications of both the time component and the radial component of a spherically symmetric metric. A modified Schwarzschild geometry is obtained as an example of its simplest application.
The Minimal Geometric Deformation Approach Extended
Casadio, Roberto; Ovalle, Jorge; da Rocha, Roldao
2015-01-01
The minimal geometric deformation approach was introduced in order to study the exterior space-time around spherically symmetric self-gravitating systems, like stars or similar astrophysical objects as well, in the Randall-Sundrum brane-world framework. A consistent extension of this approach is developed here, which contains modifications of both the time component and the radial component of a spherically symmetric metric. A modified Schwarzschild geometry is obtained as an example of its s...
Analysis of deformations of large earth dams
Szostak-Chrzanowski, Anna; Massiéra, Michel; Chrzanowski, Adam
2007-09-01
Safety of earth dams depends on the proper design, construction, and monitoring of actual behaviour during the construction and during the operation of the structure. The most critical factor in the assessment of the safety threshold value of any structure is the acceleration of its deformation. Therefore, the designed accuracy of monitoring surveys must fulfill requirements of detecting accelerations at critical locations of the investigated object. As an example, time dependant behavior of a large embankment dam during filling up the reservoir has been analyzed and verified by comparing monitoring results with the deterministic (prediction) model of the deformation. The geotechnical and geodetic monitoring besides providing a warning system in case of an abnormal behaviour of the dam, may be used as a tool for a verification of design parameters where geotechnical parameters are of the highest importance. Modeling of deformation of earth dams is a complex process in which one should consider the nonlinear behaviour of the construction material, interaction between the structure and the underlying foundation strata, influence of water load on the structure and on the foundation bedrock, and the effects of water saturation. Due to the uncertainty of the model parameters, careful monitoring of the dam and its surroundings are required in order to verify and enhance the model. In addition, with properly designed monitoring surveys, one may also determine the actual deformation mechanism. The finite element method may be useful tool in the proper design of the monitoring scheme by providing information on the locations and magnitude of the expected maximum displacements and velocites of movements. The discussed problems are illustrated by three types of earth dams located in California, U.S.A. and in Quebec, Canada.
Real Time Haptic Simulation of Deformable Bodies
Zhao, Chen
2010-01-01
In this thesis, a force modeling method for haptic simulations of deformable bodies is presented. It can be used in different areas, such as virtual reality, telepresence and robotics. The numerical models are based on the finite element method. The modeling procedure includes geometric measurement and modeling, as well as implementation of material characteristics. By the implementation of constitutive equations, linear elasticity, viscoelasticity and inhomogeneity are taken into account. In...
Deformable mirror for high power laser applications
Czech Academy of Sciences Publication Activity Database
Mrňa, Libor; Šarbort, Martin; Holá, Miroslava
Bellingham : SPIE, 2014, 94420W: 1-5. ISBN 9781628415575. ISSN 0277-786X. [ Optics and Measurement Conference 2014 (OaM 2014). Liberec (CZ), 07.10.2014-10.10.2014] R&D Projects: GA MŠk ED0017/01/01; GA MŠk(CZ) LO1212; GA TA ČR TA04020456 Institutional support: RVO:68081731 Keywords : deformable mirror * high power laser * adaptive optics Subject RIV: BH - Optics , Masers, Laser s
Coseismic deformation induced by the Sumatra earthquake
Boschi, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione AC, Roma, Italia; Casarotti, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Devoti, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Melini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Piersanti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Pietrantonio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Riguzzi, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia
2006-01-01
The giant Sumatra-Andaman earthquake of December 26, 2004 caused permanent deformations effects in a region of previously never observed extension. The GPS data from the worldwide network of permanent IGS sites show significant coseismic displacements in an area exceeding 107 km2, reaching most of South-East Asia, besides Indonesia and India. We have analyzed long GPS time series histories in order to characterize the noise type of each site and, consequently, to precisely assess the...