无
2002-01-01
Extensional basins include mainly grabens and half grabens displaced along a lower detachment. Based on area balance theory, there is a linear relationship between a height of regional and the lower detachment h on the outside of the basin and "lost area S" from the regional in the basin. The pre-growth beds above lower detachment are of the same extensional displacement so that an "S-h diagram" can be used to determine the depth to lower detachment and to calculate the total extensional displacement of the beds above the lower detachment. The extensional displacement is dominated by the heave of various scale normal faults. The displacement of obvious faults can be immediately figured out from the measured bed-length. The requisite extension calculated by area balance is the layer-parallel strain, which could be accommodated by displacement on sub-resolution faults. Accordingly, the layer-parallel strain can help us predict the magnitude and distribution of sub-resolution faults on the basis of analysis of the structural style and rheological behavior.
Cirrincione, Rosolino; Fazio, Eugenio; Ortolano, Gaetano; Fiannacca, Patrizia; Kern, Hartmut; Mengel, Kurt; Pezzino, Antonino; Punturo, Rosalda
2016-04-01
The present contribution deals with quantitative microstructural analysis, which was performed on granodiorites of the syn-tectonic Symvolon pluton (Punturo et al., 2014) at the south-western boundary of the Rhodope Core Complex (Greece). Our purpose is the quantification of ductile strain rate achieved across the pluton, by considering its cooling gradient from the centre to the periphery, using the combination of a paleopiezometer (Shimizu, 2008) and a quartz flow law (Hirth et al., 2001). Obtained results, associated with a detailed cooling history (Dinter et al., 1995), allowed us to reconstruct the joined cooling and strain gradient evolution of the pluton from its emplacement during early Miocene (ca. 700°C at 22 Ma) to its following cooling stage (ca. 500-300°C at 15 Ma). Shearing temperature values were constrained by means of a thermodynamic approach based on the recognition of syn-shear assemblages at incremental strain; to this aim, statistical handling of mineral chemistry X-Ray maps was carried out on microdomains detected at the tails of porphyroclasts. Results indicate that the strain/cooling gradients evolve "arm in arm" across the pluton, as also testified by the progressive development of mylonitic fabric over the magmatic microstructures approaching the host rock. References • Dinter, D. A., Macfarlane, A., Hames, W., Isachsen, C., Bowring, S., and Royden, L. (1995). U-Pb and 40Ar/39Ar geochronology of the Symvolon granodiorite: Implications for the thermal and structural evolution of the Rhodope metamorphic core complex, northeastern Greece. Tectonics, 14 (4), 886-908. • Shimizu, I. (2008). Theories and applicability of grain size piezometers: The role of dynamic recrystallization mechanisms. Journal of Structural Geology, 30 (7), 899-917. • Hirth, G., Teyssier, C., and Dunlap, J. W. (2001). An evaluation of quartzite flow laws based on comparisons between experimentally and naturally deformed rocks. International Journal of Earth
Rey, P. F.; Teyssier, C.; Whitney, D. L.
2009-11-01
geothermal gradient (35 to 65 °C km - 1 ); material remains partially molten in the dome during ascent. At low strain rate (mm yr - 1 in the core complex region), the partially molten crust crystallizes at high pressure; this material is subsequently deformed in the solid-state along a cooler geothermal gradient (20 to 35 °C km - 1 ) during ascent. Therefore, the models predict distinct crystallization versus exhumation histories of migmatite cores as a function of extensional strain rates. The Shuswap metamorphic core complex (British Columbia, Canada) exemplifies a metamorphic core complex in which an asymmetric, detachment-controlled migmatite dome records rapid exhumation and cooling likely related to faster rates of extension. In contrast the Ruby Mountain-East Humboldt Ranges (Nevada, U.S.A.) exhibits characteristics associated with slower metamorphic core complexes.
Zhao, Haonan; Guo, Zhaojie; Yu, Xiangjiang
2017-02-01
This paper focuses on the strain modelling of extensional fault-propagation folds to reveal the effects of key factors on the strain accumulation and the relationship between the geometry and strain distribution of fault-related folds. A velocity-geometry-strain method is proposed for the analysis of the total strain and its accumulation process within the trishear zone of an extensional fault-propagation fold. This paper improves the non-linear trishear model proposed by Jin and Groshong (2006). Based on the improved model, the distribution of the strain rate within the trishear zone and the total strain are obtained. The numerical simulations of different parameters performed in this study indicate that the shape factor R, the total apical angle, and the P/S ratio control the final geometry and strain distribution of extensional fault-propagation folds. A small P/S ratio, a small apical angle, and an R value far greater or far smaller than 1 produce an asymmetric, narrow, and strongly deformed trishear zone. The velocity-geometry-strain analysis method is applied to two natural examples from Big Brushy Canyon in Texas and the northwestern Red Sea in Egypt. The strain distribution within the trishear zone is closely related to the geometry of the folds.
Mechanical Models of Bed-Perpendicular Fractures in Layered Rocks Subjected to Extensional Strain
Sanz, P.; Pollard, D. D.; Borja, R. I.
2010-12-01
Natural fractures (joints) enhance permeability and therefore are important for the economical production of low-permeability hydrocarbon reservoirs and aquifers. In this work we investigate the formation of bed-perpendicular joints during extension in a stiff brittle layer surrounded by thick softer layers. The quasi-static finite element models consist of three elasto-plastic layers with frictional bedding interfaces and the middle layer contains layer-perpendicular fractures that can accommodate opening at the bedding surface accompanied by interface sliding. The upper and lower boundaries are subject to normal tractions appropriate for the depth of burial. Lateral boundaries are displaced horizontally to represent the extensional tectonic regime. We use an interface model that captures the most important mechanical features during sliding of bedding interfaces and opening of joints: unilateral contact, elastic and plastic relative deformation, tensile strength, cohesion, frictional sliding, and non-associative plastic flow. The constitutive law extends the Coulomb slip criterion to the tensile regime to capture opening of fractures in a quasi-brittle manner. The finite element implementation employs a penalty scheme to impose the contact constraints along the interfaces. The numerical simulations show the effects of mechanical properties of layers and interfaces in the development and spacing of bed-perpendicular joints. We evaluate the concepts of fracture saturation and sequential infilling, and the relationship between joint spacing and layer thickness in the context of the new modeling capabilities.
Bessiere, Eloïse; Rabillard, Aurélien; Arbaret, Laurent; Jolivet, Laurent; Augier, Romain; Menant, Armel
2016-04-01
Naxos Island is part of the central Cyclades (Aegean Sea, Greece) where a series of migmatite-cored metamorphic domes were exhumed below large-scale detachment systems during a Cenozoic back-arc extension. On Naxos, the Miocene exhumation history of the high-temperature metamorphic dome was notably achieved through two anastomosing and closely spaced top-to-the-north detachments belonging to the Naxos-Paros detachment system. According to previous contributions, the late exhumation stages were accompanied by the emplacement of a syn-kinematic I-type granodiorite that intruded a ductile-then-brittle detachment. Later the detachment migrated at the interface between the pluton and the metamorphic unit under ductile-to-brittle conditions. To clarify how extensional deformation was precisely distributed within the pluton, a multi-scale approach from field observations to laboratory investigations was undertaken. Through macro- to micro-structural observations, we show a continuous deformation history from magmatic to solid-state ductile/brittle conditions under an overall north-directed shearing deformation. The early magmatic or sub-solidus deformation is evidenced in a large part of the granodiorite, notably in its southern part where the original intrusive contact is still preserved. Solid-state deformation is recorded further north when approaching the detachment zone, highlighted by a thicker cataclastic zone and numerous pseudotachylite veins. From these field observations, we defined six strain facies, leading us to propose a qualitative strain map of the Naxos granodiorite. Based on field pictures and X-ray tomography of oriented samples collected along the strain gradient, we quantified the intensity of mineralogical fabrics in 2D and 3D. This step required the treatment of 600 rocks samples and pictures using SPO2003 (Shape Preferred Orientation) and Intercepts2003. Measured shape variations of the strain ellipsoid thus corroborate the large-scale strain
2008-12-01
Full Text Available The variation of electrical resistivity as will as the mechanical properties of PVC (polyvinylchloride-NBR (acrylonitrile butadiene rubber based conductive composites filled with different concentrations of graphite were studied. These samples were studied as function of the constant deformation fatigue test. When the specimen was subjected to a large number of rapidly repeating strain cycles, and different strain amplitudes, the conductivity, σ(T, shows an initial rapid fall followed by dynamic equilibrium. Increasing the number of cycles and strain amplitudes, the conductivity remains almost constant over the temperature range 30–140°C. The equilibrium state between destruction and reconstruction of graphite particles has been detected for all strains of certain values of strain cycles (1000, 2000, 3000, and 4000 cycles for 30% strain amplitude. A preliminary study was done to optimize the possibility to use Conductive Polymer Composites (CPC as a strain sensor and to evaluate its performance by an intrinsic physico-mechanical modification measurement. The electromechanical characterization was performed to demonstrate the adaptability and the correct functioning of the sensor as a strain gauge on the fabric. The coefficient of strain sensitivity (K was measured for 50 phr graphite/PVCNBR vulcanized at 3000 number of strain cycles and 30% strain amplitude. There was a broad maximum of K, with a peak value of 82, which was much higher, compared to conventional wire resistors. A slight hysteresis was observed at unloading due to plasticity of the matrix. A good correlation exists between mechanical and electrical response to the strain sensitivity. Mechanical reinforcement was in accordance with the Quemada equation [1] and Guth model [2] attested to good particle-matrix adhesion. It was found that the viscous component of deformation gradually disappeared and the hardening occurred with increasing strain cycles. The modulus, fracture
Friedrich, A.; Wernicke, B.; Lee, J.; Sieh, K.
2003-04-01
The northern Basin and Range province is one of the largest continental extensional regions on earth. At 40 degrees N latitude, the province is 800 km wide and consists of 15 and 20 N-S striking normal faults. These faults accommodated mainly east-west directed extension of tens of kilometers since Mid-Miocene time and recent geodetic surveys show that extension is still active today at a rate of ~1.5 cm/yr across the province (e.g., Bennett et al. 2000; Thatcher et al. 1999). The distribution of this geodetically measurable strain accumulation within the province, however, contradicts geologic observations across some of the active normal faults. For example, coordinated geologic and geodetic measurements across the Crescent Valley fault (CVF), north-central Nevada, reveal a profound mismatch in deformation rates. Since 1996, the two ranges on either side of the CVF have been moving toward each other at ca. 2 mm/yr, indicating shortening. In contrast, new reconnaissance mapping and paleoseismological analyses along the CVF also indicate that this fault is one of the more active normal faults of the Basin and Range province. The 50 km long Cortez Mountains range front is characterized by relief of up to 1.3 km, steep (up to 36 degrees) triangular facets, and young (late Pleistocene to late Holocene) alluvial fans cut by normal fault scarps. Vertical displacement across the CVF is ca. 3 km; since 15 Ma the average long-term vertical displacement rate is ca. 0.2 mm/yr. Topographic profiling shows that fault scarps, 2-7 m high, are the result of a single rupture event and cut late Holocene alluvial fans. A trench across a faulted alluvial fan at Fourmile Canyon reveals a vertical displacement of 4.5 m distributed across two normal faults. 14C analyses on charcoal from a buried offset surface in the hanging wall of the trench and from the base of the overlying colluvial wedge tightly bracket the age of the most recent earthquake to between 2.8 +- 0.1 and 2.7 +- 0.1 ka
A new look at extensional rheology of low-density polyethylene
Huang, Qian; Mangnus, Marc; Alvarez, Nicolas J.
2016-01-01
The nonlinear rheology of three selected commercial low-density polyethylenes (LDPE) is measured in uniaxial extensional flow. The measurements are performed using three different devices including an extensional viscosity fixture (EVF), a homemade filament stretching rheometer (DTU-FSR) and a co......The nonlinear rheology of three selected commercial low-density polyethylenes (LDPE) is measured in uniaxial extensional flow. The measurements are performed using three different devices including an extensional viscosity fixture (EVF), a homemade filament stretching rheometer (DTU......-FSR) and a commercial filament stretching rheometer (VADER-1000). We show that the measurements from the EVF are limited by a maximum Hencky strain of 4, while the two filament stretching rheometers are able to probe the nonlinear behavior at larger Hencky strain values where the steady state is reached...
Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Groshong, R.H.
1997-08-01
Gilbertown Field is the oldest oil field in Alabama and produces oil from chalk of the Upper Cretaceous Selma Group and from sandstone of the Eutaw Formation along the southern margin of the Gilbertown fault system. Most of the field has been in primary recovery since establishment, but production has declined to marginally economic levels. This investigation applies advanced geologic concepts designed to aid implementation of improved recovery programs. The Gilbertown fault system is detached at the base of Jurassic salt. The fault system began forming as a half graben and evolved in to a full graben by the Late Cretaceous. Conventional trapping mechanisms are effective in Eutaw sandstone, whereas oil in Selma chalk is trapped in faults and fault-related fractures. Burial modeling establishes that the subsidence history of the Gilbertown area is typical of extensional basins and includes a major component of sediment loading and compaction. Surface mapping and fracture analysis indicate that faults offset strata as young as Miocene and that joints may be related to regional uplift postdating fault movement. Preliminary balanced structural models of the Gilbertown fault system indicate that synsedimentary growth factors need to be incorporated into the basic equations of area balance to model strain and predict fractures in Selma and Eutaw reservoirs.
Philipsen, Kirsten Riber; Christiansen, Lasse Engbo; Mandsberg, Lotte Frigaard
2008-01-01
that best describes data is a model taking into account the full covariance structure. An inference study is made in order to determine whether the growth rate of the five bacteria strains is the same. After applying a likelihood-ratio test to models with a full covariance structure, it is concluded...... that the specific growth rate is the same for all bacteria strains. This study highlights the importance of carrying out an explorative examination of residuals in order to make a correct parametrization of a model including the covariance structure. The ML method is shown to be a strong tool as it enables......The specific growth rate for P. aeruginosa and four mutator strains mutT, mutY, mutM and mutY–mutM is estimated by a suggested Maximum Likelihood, ML, method which takes the autocorrelation of the observation into account. For each bacteria strain, six wells of optical density, OD, measurements...
Tanabe, Yuki; Kido, Teruhito; Kurata, Akira; Sawada, Shun; Suekuni, Hiroshi; Kido, Tomoyuki; Yokoi, Takahiro; Miyagawa, Masao; Mochizuki, Teruhito [Ehime University Graduate School of Medicine, Department of Radiology, Toon City, Ehime (Japan); Uetani, Teruyoshi; Inoue, Katsuji [Ehime University Graduate School of Medicine, Department of Cardiology, Pulmonology, Hypertension and Nephrology, Toon City, Ehime (Japan)
2017-04-15
To evaluate the feasibility of three-dimensional (3D) maximum principal strain (MP-strain) derived from cardiac computed tomography (CT) for detecting myocardial infarction (MI). Forty-three patients who underwent cardiac CT and magnetic resonance imaging (MRI) were retrospectively selected. Using the voxel tracking of motion coherence algorithm, the peak CT MP-strain was measured using the 16-segment model. With the trans-mural extent of late gadolinium enhancement (LGE) and the distance from MI, all segments were classified into four groups (infarcted, border, adjacent, and remote segments); infarcted and border segments were defined as MI with LGE positive. Diagnostic performance of MP-strain for detecting MI was compared with per cent systolic wall thickening (%SWT) assessed by MRI using receiver-operating characteristic curve analysis at a segment level. Of 672 segments excluding16 segments influenced by artefacts, 193 were diagnosed as MI. Sensitivity and specificity of peak MP-strain to identify MI were 81 % [95 % confidence interval (95 % CI): 74-88 %] and 86 % (81-92 %) compared with %SWT: 76 % (60-95 %) and 68 % (48-84 %), respectively. The area under the curve of peak MP-strain was superior to %SWT [0.90 (0.87-0.93) vs. 0.80 (0.76-0.83), p < 0.05]. CT MP-strain has a potential to provide incremental value to coronary CT angiography for detecting MI. (orig.)
Curiale, Ariel H; Vegas-Sánchez-Ferrero, Gonzalo; Bosch, Johan G; Aja-Fernández, Santiago
2015-08-01
The strain and strain-rate measures are commonly used for the analysis and assessment of regional myocardial function. In echocardiography (EC), the strain analysis became possible using Tissue Doppler Imaging (TDI). Unfortunately, this modality shows an important limitation: the angle between the myocardial movement and the ultrasound beam should be small to provide reliable measures. This constraint makes it difficult to provide strain measures of the entire myocardium. Alternative non-Doppler techniques such as Speckle Tracking (ST) can provide strain measures without angle constraints. However, the spatial resolution and the noisy appearance of speckle still make the strain estimation a challenging task in EC. Several maximum likelihood approaches have been proposed to statistically characterize the behavior of speckle, which results in a better performance of speckle tracking. However, those models do not consider common transformations to achieve the final B-mode image (e.g. interpolation). This paper proposes a new maximum likelihood approach for speckle tracking which effectively characterizes speckle of the final B-mode image. Its formulation provides a diffeomorphic scheme than can be efficiently optimized with a second-order method. The novelty of the method is threefold: First, the statistical characterization of speckle generalizes conventional speckle models (Rayleigh, Nakagami and Gamma) to a more versatile model for real data. Second, the formulation includes local correlation to increase the efficiency of frame-to-frame speckle tracking. Third, a probabilistic myocardial tissue characterization is used to automatically identify more reliable myocardial motions. The accuracy and agreement assessment was evaluated on a set of 16 synthetic image sequences for three different scenarios: normal, acute ischemia and acute dyssynchrony. The proposed method was compared to six speckle tracking methods. Results revealed that the proposed method is the most
XU Shunshan; A. F. NIETO-SAMANIEGO; S. A. ALANIZ-(A)LVAREZ
2005-01-01
The Sierra de San Miguelito is a relatively uplifted area and is constituted by a large amount of silicic volcanic rocks with ages from middle to late Cenozoic. The normal faults of the Sierra de San Miguelito are Domino-style and nearly parallel. The cumulative length and displacement of the faults obey power-law distribution. The fractal dimension of the fault traces is -1.49. Using the multi-line one-dimensional sampling, the calculated exponent of cumulative fault displacements is -0.66. A cumulative curve combining measurements of all four sections yielded a slope of -0.63. The displacement-length plot shows a non-linear relationship and large dispersion of data. The large dispersion in the plot is mainly due to the fault linkage during faulting. An estimation of extensional strain due to the normal faults is ca. 0.1830.The bed extension strain is always less than or equal to the horizontal extension strain. The deformation in the Sierra de San Miguelito occurred near the surface, producing pervasive faults and many faults are too small to appear in maps and sections at common scales. The stretching produced by small faults reach ca. 33% of the total horizontal elongation.
Risk of shear failure and extensional failure around over-stressed excavations in brittle rock
Nick Barton
2017-04-01
Full Text Available The authors investigate the failure modes surrounding over-stressed tunnels in rock. Three lines of investigation are employed: failure in over-stressed three-dimensional (3D models of tunnels bored under 3D stress, failure modes in two-dimensional (2D numerical simulations of 1000 m and 2000 m deep tunnels using FRACOD, both in intact rock and in rock masses with one or two joint sets, and finally, observations in TBM (tunnel boring machine tunnels in hard and medium hard massive rocks. The reason for ‘stress-induced’ failure to initiate, when the assumed maximum tangential stress is approximately (0.4–0.5σc (UCS, uniaxial compressive strength in massive rock, is now known to be due to exceedance of a critical extensional strain which is generated by a Poisson's ratio effect. However, because similar ‘stress/strength’ failure limits are found in mining, nuclear waste research excavations, and deep road tunnels in Norway, one is easily misled into thinking of compressive stress induced failure. Because of this, the empirical SRF (stress reduction factor in the Q-system is set to accelerate as the estimated ratio σθmax/σc >> 0.4. In mining, similar ‘stress/strength’ ratios are used to suggest depth of break-out. The reality behind the fracture initiation stress/strength ratio of ‘0.4’ is actually because of combinations of familiar tensile and compressive strength ratios (such as 10 with Poisson's ratio (say 0.25. We exceed the extensional strain limits and start to see acoustic emission (AE when tangential stress σθ ≈ 0.4σc, due to simple arithmetic. The combination of 2D theoretical FRACOD models and actual tunnelling suggests frequent initiation of failure by ‘stable’ extensional strain fracturing, but propagation in ‘unstable’ and therefore dynamic shearing. In the case of very deep tunnels (and 3D physical simulations, compressive stresses may be too high for extensional strain fracturing, and
Transient Overshoot Extensional Rheology: Experimental and Numerical Comparisons
Hoyle, David; Huang, Qian; Auhl, Dietmar
rheometer (FSR) and the cross-slot extensional rheometer (CSER). The first two are uni-axial stretching rheometers and the third is a planar extensional rheometer. The FSR and CSER are capable of achieving steady state flows, although in different strain-rate regimes. The SER has been a widely adopted tool....... Although we are comparing uni-axial to planar flow, these flows produce the same polymer deformation and hence stress in the strain hardening regime. The techniques show a good quantitative agreement where the two experimental windows overlap. In comparing the FSR to the CSER we are able to explain...
Im, Jooeun; Kim, Mihyun; Choi, Ki-Sun; Hwang, Tae-Kyung; Kwon, Il-Bum
2014-06-10
In this paper, new fiber Bragg grating (FBG) sensor probes are designed to intermittently detect the maximum tensile strain of composite materials, so as to evaluate the structural health status. This probe is fabricated by two thin Al films bonded to an FBG optical fiber and two supporting brackets, which are fixed on the surface of composite materials. The residual strain of the Al packaged FBG sensor probe is induced by the strain of composite materials. This residual strain can indicate the maximum strain of composite materials. Two types of sensor probes are prepared-one is an FBG with 18 μm thick Al films, and the other is an FBG with 36 μm thick Al films-to compare the thickness effect on the detection sensitivity. These sensor probes are bonded on the surfaces of carbon fiber reinforced plastics composite specimens. In order to determine the strain sensitivity between the residual strain of the FBG sensor probe and the maximum strain of the composite specimen, tensile tests are performed by universal testing machine, under the loading-unloading test condition. The strain sensitivities of the probes, which have the Al thicknesses of 18 and 36 μm, are determined as 0.13 and 0.23, respectively.
Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Carroll, R.E.; Groshong, R.H.; Jin, G.
1998-12-01
This project was designed to analyze the structure of Mesozoic and Tertiary strata in Gilbertown Field and adjacent areas to suggest ways in which oil recovery can be improved. The Eutaw Formation comprises 7 major flow units and is dominated by low-resistivity, low-contrast play that is difficult to characterize quantitatively. Selma chalk produces strictly from fault-related fractures that were mineralized as warm fluid migrated from deep sources. Resistivity, dipmeter, and fracture identification logs corroborate that deformation is concentrated in the hanging-wall drag zones. New area balancing techniques were developed to characterize growth strata and confirm that strain is concentrated in hanging-wall drag zones. Curvature analysis indicates that the faults contain numerous fault bends that influence fracture distribution. Eutaw oil is produced strictly from footwall uplifts, whereas Selma oil is produced from fault-related fractures. Clay smear and mineralization may be significant trapping mechanisms in the Eutaw Formation. The critical seal for Selma reservoirs, by contrast, is where Tertiary clay in the hanging wall is juxtaposed with poorly fractured Selma chalk in the footwall. Gilbertown Field can be revitalized by infill drilling and recompletion of existing wells. Directional drilling may be a viable technique for recovering untapped oil from Selma chalk. Revitalization is now underway, and the first new production wells since 1985 are being drilled in the western part of the field.
Quantum Ontology and Extensional Mereology
Calosi, Claudio; Fano, Vincenzo; Tarozzi, Gino
2011-11-01
The present paper has three closely related aims. We first argue that Agazzi's scientific realism about Quantum Mechanics is in line with Selleri's and Tarozzi's proposal of Quantum Waves. We then go on to formulate rigorously different metaphysical principles such as property compositional determinateness and mereological extensionalism. We argue that, contrary to widespread agreement, realism about Quantum Mechanics actually refutes only the former. Indeed we even formulate a new quantum mechanical argument in favor of extensionalism. We conclude by noting that, given the results of the work, Agazzi's particular attitude towards Quantum Mechanics is still one of the most promising theoretical perspectives.
Sandbox Modeling of the Fault-increment Pattern in Extensional Basins
Geng Changbo; Tong Hengmao; He Yudan; Wei Chunguang
2007-01-01
Three series of sandbox modeling experiments were performed to study the fault-increment pattern in extensional basins.Experimental results showed that the tectonic action mode of boundaries and the shape of major boundary faults control the formation and evolution of faults in extensional basins.In the process of extensional deformation,the increase in the number and length of faults was episodic,and every 'episode' experienced three periods,strain-accumulation period,quick fault-increment period and strain-adjustment period.The more complex the shape of the boundary fault,the higher the strain increment each 'episode' experienced.Different extensional modes resulted in different fault-increment patterns.The horizontal detachment extensional mode has the 'linear' style of fault-increment pattern,while the extensional mode controlled by a listric fault has the 'stepwise' style of fault-increment pattern,and the extensional mode controlled by a ramp-flat boundary fault has the 'stepwise-linear' style of fault-increment pattern.These fault-increment patterns given above could provide a theoretical method of fault interpretation and fracture prediction in extensional basins.
Pressure Effect on Extensional Viscosity
Christensen, Jens Horslund; Kjær, Erik Michael
1999-01-01
The primary object of these experiments was to investigate the influence of hydrostatic pressure on entrance flow. The effect of pressure on shear and extensional viscosity was evaluated using an axis symmetric capillary and a slit die where the hydrostatic pressure was raised with valves...
Sung Woo Park
2015-03-01
Full Text Available The safety of a multi-span waler beam subjected simultaneously to a distributed load and deflections at its supports can be secured by limiting the maximum stress of the beam to a specific value to prevent the beam from reaching a limit state for failure or collapse. Despite the fact that the vast majority of accidents on construction sites occur at waler beams in retaining wall systems, no safety monitoring model that can consider deflections at the supports of the beam is available. In this paper, a maximum stress estimation model for a waler beam based on average strains measured from vibrating wire strain gauges (VWSGs, the most frequently used sensors in construction field, is presented. The model is derived by defining the relationship between the maximum stress and the average strains measured from VWSGs. In addition to the maximum stress, support reactions, deflections at supports, and the magnitudes of distributed loads for the beam structure can be identified by the estimation model using the average strains. Using simulation tests on two multi-span beams, the performance of the model is evaluated by estimating maximum stress, deflections at supports, support reactions, and the magnitudes of distributed loads.
A.H. Curiale (Ariel H.); G. Vegas-Sanchez-Ferrero (Gonzalo); J.G. Bosch (Hans); S. Aja-Fernández (Santiago)
2015-01-01
textabstractThe strain and strain-rate measures are commonly used for the analysis and assessment of regional myocardial function. In echocardiography (EC), the strain analysis became possible using Tissue Doppler Imaging (TDI). Unfortunately, this modality shows an important limitation: the angle
A.H. Curiale (Ariel H.); G. Vegas-Sanchez-Ferrero (Gonzalo); J.G. Bosch (Johan); S. Aja-Fernández (Santiago)
2015-01-01
textabstractThe strain and strain-rate measures are commonly used for the analysis and assessment of regional myocardial function. In echocardiography (EC), the strain analysis became possible using Tissue Doppler Imaging (TDI). Unfortunately, this modality shows an important limitation: the angle b
Hyperbolic contraction measuring systems for extensional flow
Nyström, M.; Tamaddon Jahromi, H. R.; Stading, M.; Webster, M. F.
2017-08-01
In this paper an experimental method for extensional measurements on medium viscosity fluids in contraction flow is evaluated through numerical simulations and experimental measurements. This measuring technique measures the pressure drop over a hyperbolic contraction, caused by fluid extension and fluid shear, where the extensional component is assumed to dominate. The present evaluative work advances our previous studies on this experimental method by introducing several contraction ratios and addressing different constitutive models of varying shear and extensional response. The constitutive models included are those of the constant viscosity Oldroyd-B and FENE-CR models, and the shear-thinning LPTT model. Examining the results, the impact of shear and first normal stress difference on the measured pressure drop are studied through numerical pressure drop predictions. In addition, stream function patterns are investigated to detect vortex development and influence of contraction ratio. The numerical predictions are further related to experimental measurements for the flow through a 15:1 contraction ratio with three different test fluids. The measured pressure drops are observed to exhibit the same trends as predicted in the numerical simulations, offering close correlation and tight predictive windows for experimental data capture. This result has demonstrated that the hyperbolic contraction flow is well able to detect such elastic fluid properties and that this is matched by numerical predictions in evaluation of their flow response. The hyperbolical contraction flow technique is commended for its distinct benefits: it is straightforward and simple to perform, the Hencky strain can be set by changing contraction ratio, non-homogeneous fluids can be tested, and one can directly determine the degree of elastic fluid behaviour. Based on matching of viscometric extensional viscosity response for FENE-CR and LPTT models, a decline is predicted in pressure drop for
Hyperbolic contraction measuring systems for extensional flow
Nyström, M.; Tamaddon Jahromi, H. R.; Stading, M.; Webster, M. F.
2017-02-01
In this paper an experimental method for extensional measurements on medium viscosity fluids in contraction flow is evaluated through numerical simulations and experimental measurements. This measuring technique measures the pressure drop over a hyperbolic contraction, caused by fluid extension and fluid shear, where the extensional component is assumed to dominate. The present evaluative work advances our previous studies on this experimental method by introducing several contraction ratios and addressing different constitutive models of varying shear and extensional response. The constitutive models included are those of the constant viscosity Oldroyd-B and FENE-CR models, and the shear-thinning LPTT model. Examining the results, the impact of shear and first normal stress difference on the measured pressure drop are studied through numerical pressure drop predictions. In addition, stream function patterns are investigated to detect vortex development and influence of contraction ratio. The numerical predictions are further related to experimental measurements for the flow through a 15:1 contraction ratio with three different test fluids. The measured pressure drops are observed to exhibit the same trends as predicted in the numerical simulations, offering close correlation and tight predictive windows for experimental data capture. This result has demonstrated that the hyperbolic contraction flow is well able to detect such elastic fluid properties and that this is matched by numerical predictions in evaluation of their flow response. The hyperbolical contraction flow technique is commended for its distinct benefits: it is straightforward and simple to perform, the Hencky strain can be set by changing contraction ratio, non-homogeneous fluids can be tested, and one can directly determine the degree of elastic fluid behaviour. Based on matching of viscometric extensional viscosity response for FENE-CR and LPTT models, a decline is predicted in pressure drop for
Deriving Extensional Spatial Composition Tables
El-Geresy, Baher; Abdelmoty, Alia I.; Ware, Andrew J.
Spatial composition tables are fundamental tools for the realisation of qualitative spatial reasoning techniques. Studying the properties of these tables in relation to the spatial calculi they are based on is essential for understanding the applicability of these calculi and how they can be extended and generalised. An extensional interpretation of a spatial composition table is an important property that has been studied in the literature and is used to determine the validity of the table for the models it is proposed for. It provides means for consistency checking of ground sets of relations and for addressing spatial constraint satisfaction problems. Furthermore, two general conditions that can be used to test for extensionality of spatial composition tables are proposed and applied to the RCC8 composition table to verify the allowable models in this calculus.
Hydrodynamic extensional stress during the bubble bursting process for bioreactor system design
Tran, Thanh Tinh; Lee, Eun Gyo; Lee, In Su; Woo, Nam Sub; Han, Sang Mok; Kim, Young Ju; Hwang, Wook Ryol
2016-11-01
Cell damage, one of critical issues in the bioreactor design for animal cell culture, is caused mainly from the bubble bursting at the free surface subjected to strong extensional flows. In this work, extensive computational studies are performed to investigate bubble bursting process in great details. Extensive numerical simulations are performed for a wide range of bubble diameters (from 0.5 to 6 mm) and the surface tension values (from 0.03 to 0.072 N/m), with which effects of the bubble size and surfactant (PF68) concentration on the hydrodynamic stress are investigated. For all the cases, the maximum extensional stress appears at the instance when receding films impact each other at the bottom of the bubble. A model equation based on numerical simulations is presented to predict the maximum extensional stress as a function of the bubble diameter and the surface tension. The bubble diameter has turned out to contribute significantly the maximum hydrodynamic extensional stress. In addition, the bubble collapsed time and the affected volume around a bubble subjected to the critical extensional stress are investigated. The extensional stress estimation is reported as a function of the bubble size and the surface tension. The influence of the bubble size on the maximum stress dominates and extensional stress reaches up to the order of 104 Pa for bubble size of 0.5 mm.
Development and modeling of novel extensional ionic polymer transducers
Akle, Barbar; Wallmersperger, Thomas; Leo, Donald
2007-04-01
Ionic polymer transducers (IPT), sometimes referred to as artificial muscles, are known to generate a large bending strain and a moderate stress at low applied voltages. Bending actuators have limited engineering applications due to the low forcing capabilities and the need for complicated external devices to convert the bending action into rotating or linear motion desired in most devices. Recently Akle and Leo (2006) reported extensional actuation in ionic polymer transducers. Model prediction indicates that such actuators can produce strain up to 10% and a blocked stress up to 20MPa under a +/- 2V applied electric potential. Compared to other smart materials, IPT is a flexible membrane and it has a reliability of over one million cycles. In this work novel extensional IPT actuators are developed for the purpose of increasing the overall displacement of the actuator. The electromechanical coupling is measured and a correlation of the experimental data with the active areas model by Akle and Leo (2006) and the numerical electromechanical model by Wallmersperger and Leo (2004) are presented. The coupling between each test case with the model parameters enables further understanding of the physical actuation phenomena as the role of diffusion of ions and diluents and the electrostatic forces between the charged species. In this study the displacement of an extensional ionic polymer transducer is measured and compared to the bending of the same IPT actuator. The bending strain is measured to be approximately 2.5%, while the extensional strain for the same ionomer is in the order of 17.5%. Finally an interesting behavior, reported for the first time is the steady expansion of the IPT sample due to the application of a symmetrical sine wave. This indicates that charge accumulation is occurring at the electrode.
Prediction of Maximum Strain in Finocyl Port Case-bonded Solid Propellants under Pressure Loading
Himanshu Shekhar
2006-07-01
Full Text Available Finite element analysis of case-bonded solid propellants in finocyl port configuration hasbeen carried out using finite element method. The parametric studies have also been conductedfor loading conditions, material properties, and geometrical configurations. The results arepresented in the form of a universal power law, which can be utilised for primary assessmentof peak strain in any finocyl port propellant configuration without using finite element software.This eliminates dependence on finite element software for structural integrity analysis of solidpropellants in finocyl port configuration under port pressurisation. The results obtained by finiteelement analysis and power law are in close agreement.
Philipsen, Kirsten Riber; Christiansen, Lasse Engbo; Mandsberg, Lotte Frigaard
2008-01-01
with an exponentially decaying function of the time between observations is suggested. A model with a full covariance structure containing OD-dependent variance and an autocorrelation structure is compared to a model with variance only and with no variance or correlation implemented. It is shown that the model...... are used for parameter estimation. The data is log-transformed such that a linear model can be applied. The transformation changes the variance structure, and hence an OD-dependent variance is implemented in the model. The autocorrelation in the data is demonstrated, and a correlation model...... that best describes data is a model taking into account the full covariance structure. An inference study is made in order to determine whether the growth rate of the five bacteria strains is the same. After applying a likelihood-ratio test to models with a full covariance structure, it is concluded...
Extensionality of simply typed logic programs
M.A. Bezem
1999-01-01
textabstractWe set up a framework for the study of extensionality in the context of higher-order logic programming. For simply typed logic programs we propose a novel declarative semantics, consisting of a model class with a semi-computable initial model, and a notion of extensionality. We show that
PREDICTION OF MAXIMUM CREEP STRAIN OF HIGH PERFORMANCE STEEL FIBER REINFORCED CONCRETE
Mishina Alexandra Vasil'evna
2012-12-01
Full Text Available The strongest research potential is demonstrated by the areas of application of high performance steel fiber reinforced concrete (HPSFRC. The research of its rheological characteristics is very important for the purposes of understanding its behaviour. This article is an overview of an experimental study of UHSSFRC. The study was carried out in the form of lasting creep tests of HPSFRC prism specimen, loaded by stresses of varied intensity. The loading was performed at different ages: 7, 14, 28 and 90 days after concreting. The stress intensity was 0.3 and 0.6 Rb; it was identified on the basis of short-term crush tests of similar prism-shaped specimen, performed on the same day. As a result, values of ultimate creep strains and ultimate specific creep of HPSFRC were identified. The data was used to construct an experimental diagramme of the ultimate specific creep on the basis of the HPSFRC loading age if exposed to various stresses. The research has resulted in the identification of a theoretical relationship that may serve as the basis for the high-precision projection of the pattern of changes in the ultimate specific creep of HPSFRC, depending on the age of loading and the stress intensity.
Geometry and kinematics of extensional structural wedges
Gui, Baoling; He, Dengfa; Zhang, Yongsheng; Sun, Yanpeng; Huang, Jingyi; Zhang, Wenjun
2017-03-01
Structural wedges in the compressive environment have been recognized and studied in different locations. However, extension structural wedges are less well-understood. Based on the normal fault-bend folding theory and inclined shear model, this paper quantitatively analyses deformations related to extensional structural wedges and builds a series of geometric models for them. An extensional structural wedge is a fault-block held by two or more normal faults, the action of which would fold its overlying strata. Extensional structural wedges of different shapes will lead to different deformation results for the overlying strata, and this paper illustrates both the triangular and quadrangular wedges and their related deformations. This paper also discusses differences between the extensional structural wedges and the normal fault-bend-folding. By analysing two seismic sections from Langfang-Gu'an Sag, East China, this paper provides two natural examples of the triangular and quadrangular extensional structural wedges, where the models can reasonably explain the overlying distinct highs and lows without obvious faults. The establishment of a geometric model of extensional structural wedges can provide reference and theoretical bases for future quantitative analysis of deformations in the extensional environment.
Extensional Information Articulation from the Universe
Yasufumi Saruwatari
2012-11-01
Full Text Available Information must have physical support and this physical universe comprisesphysical interactions. Hence actual information processes should have a description byinteractions alone, i.e., an extensional description. In this paper, such a model of the processof information articulation from the universe is developed by generalizing the extensivemeasurement theory in metrology. Moreover, a model of the attribute creation processis presented to exemplify a step of the informational articulation process. These modelsdemonstrate the valuableness of the extensional view and are expected to enhance theunderstanding of the extensional aspects of fundamentals of information.
Extensional scientific realism vs. intensional scientific realism.
Park, Seungbae
2016-10-01
Extensional scientific realism is the view that each believable scientific theory is supported by the unique first-order evidence for it and that if we want to believe that it is true, we should rely on its unique first-order evidence. In contrast, intensional scientific realism is the view that all believable scientific theories have a common feature and that we should rely on it to determine whether a theory is believable or not. Fitzpatrick argues that extensional realism is immune, while intensional realism is not, to the pessimistic induction. I reply that if extensional realism overcomes the pessimistic induction at all, that is because it implicitly relies on the theoretical resource of intensional realism. I also argue that extensional realism, by nature, cannot embed a criterion for distinguishing between believable and unbelievable theories.
Befus, M; Mukherjee, D V; Herzig, C T A; Lowy, F D; Larson, E
2017-07-01
Prisons/jails are thought to amplify the transmission of Staphylococcus aureus (SA) particularly methicillin-resistant SA infection and colonisation. Two independently pooled cross-sectional samples of detainees being admitted or discharged from two New York State maximum-security prisons were used to explore this concept. Private interviews of participants were conducted, during which the anterior nares and oropharynx were sampled and assessed for SA colonisation. Log-binomial regression and correspondence analysis (CA) were used to evaluate the prevalence of colonisation at entry as compared with discharge. Approximately 51% of admitted (N = 404) and 41% of discharged (N = 439) female detainees were colonised with SA. Among males, 59% of those admitted (N = 427) and 49% of those discharged (N = 393) were colonised. Females had a statistically significant higher prevalence (1·26: P = 0·003) whereas males showed no significant difference (1·06; P = 0·003) in SA prevalence between entry and discharge. CA demonstrated that some strains, such as spa types t571 and t002, might have an affinity for certain mucosal sites. Contrary to our hypothesis, the prison setting did not amplify SA transmission, and CA proved to be a useful tool in describing the population structure of strains according to time and/or mucosal site.
Constant force extensional rheometry of polymer solutions
Szabo, Peter; McKinley, Gareth H.; Clasen, Christian
2012-01-01
We revisit the rapid stretching of a liquid filament under the action of a constant imposed tensile force, a problem which was first considered by Matta and Tytus [J. Non-Newton. Fluid Mech. 35 (1990) 215–229]. A liquid bridge formed from a viscous Newtonian fluid or from a dilute polymer solution...... filament can be probed. In particular, we show that with this constant force pull (CFP) technique it is possible to readily impose very large material strains and strain rates so that the maximum extensibility of the polymer molecules may be quantified. This unique characteristic of the experiment...
Hoyle, D.M.; Huang, Qian; Auhl, D.
2013-01-01
This work analyses the high-strain extensional behavior of long-chain branched polyethylenes, employing two novel extensional rheometer devices, the filament stretching rheometer and the cross-slot extensional rheometer. The filament stretching rheometer uses an active feedback loop to control...... the outflow centre line (named W-cusps). Using constitutive modeling of the observed transient overshoot in extension seen in the filament stretching rheometer and using finite element simulations we show that the overshoot explains the W-cusps seen in the cross-slot extensional rheometer, further confirming...
Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Carroll, R.E.
1998-09-01
Gilbertown Field is the oldest oil field in Alabama and has produced oil from fractured chalk of the Cretaceous Selma Group and glauconitic sandstone of the Eutaw Formation. Nearly all of Gilbertown Field is still in primary recovery, although waterflooding has been attempted locally. The objective of this project is to analyze the geologic structure and burial history of Mesozoic and Tertiary strata in Gilbertown Field and adjacent areas in order to suggest ways in which oil recovery can be improved. Indeed, the decline of oil production to marginally economic levels in recent years has made this type of analysis timely and practical. Key technical advancements being sought include understanding the relationship of requisite strain to production in Gilbertown reservoirs, incorporation of synsedimentary growth factors into models of area balance, quantification of the relationship between requisite strain and bed curvature, determination of the timing of hydrocarbon generation, and identification of the avenues and mechanisms of fluid transport.
Asymmetric Vesicle Instability in Extensional Flow
Spann, Andrew; Zhao, Hong; Shaqfeh, Eric
2012-11-01
Previous researchers have chronicled the breakup of drops in an extensional flow as they stretch into a dumbbell shape with a long thin neck. Motivated by recent experimental observations, we study an apparently similar problem with vesicles, which are deformable but incompressible membranes that conserve area and volume. First, we simulate vesicles in an unbounded uniaxial extensional flow which are given general radial perturbations from an initially stable symmetric equilibrium state. For sufficiently low reduced volume (outer viscosity) there exists a capillary number at which an asymmetric perturbation mode will grow, resulting in the formation of an asymmetric dumbbell shape with a thin connecting cylindrical bridge analogous to the shapes associated with drop breakup. Our simulations help elucidate a mechanism for this instability based on a competition between internal pressure differentials in the vesicle resulting from the membrane bending force and ambient flow. We compare and contrast this transition to the ``standard'' drop breakup transition. Funded by NSF GRFP and Stanford Graduate Fellowship.
Extensional Information Articulation from the Universe
Yasufumi Saruwatari; Makoto Yoshitake
2012-01-01
Information must have physical support and this physical universe comprisesphysical interactions. Hence actual information processes should have a description byinteractions alone, i.e., an extensional description. In this paper, such a model of the processof information articulation from the universe is developed by generalizing the extensivemeasurement theory in metrology. Moreover, a model of the attribute creation processis presented to exemplify a step of the informational articulation p...
Microfluidic converging/diverging channels optimised for homogeneous extensional deformation
Zografos, K.; Oliveira, M. S. N.
2016-01-01
In this work, we optimise microfluidic converging/diverging geometries in order to produce constant strain-rates along the centreline of the flow, for performing studies under homogeneous extension. The design is examined for both two-dimensional and three-dimensional flows where the effects of aspect ratio and dimensionless contraction length are investigated. Initially, pressure driven flows of Newtonian fluids under creeping flow conditions are considered, which is a reasonable approximation in microfluidics, and the limits of the applicability of the design in terms of Reynolds numbers are investigated. The optimised geometry is then used for studying the flow of viscoelastic fluids and the practical limitations in terms of Weissenberg number are reported. Furthermore, the optimisation strategy is also applied for electro-osmotic driven flows, where the development of a plug-like velocity profile allows for a wider region of homogeneous extensional deformation in the flow field. PMID:27478523
Dumbbell formation for elastic capsules in nonlinear extensional Stokes flows
Dimitrakopoulos, P.
2017-06-01
Cross-slot and four-roll-mill microdevices are commonly used for particle manipulation and characterization owing to the stagnation-point flow at the device center. Because of the solid boundaries, these devices may generate extensional Stokes flows where the velocity is a nonlinear function of position associated with a decreased pressure at the particle edges and an increased pressure at the particle middle. Our computational investigation shows that in this class of Stokes flows, an elastic capsule made of a strain-hardening membrane develops two distinct steady-state conformations at strong flows, i.e., an elongated weak dumbbell shape with rounded edges at low flow nonlinearity and a laterally extended dumbbell shape at high flow nonlinearity. These effects are more pronounced for the less strain-hardening capsules which develop a flat extended middle where the two sides of the membrane approach each other. The strong stability properties of the strain-hardening capsules (owing to the development of strong membrane tensions) contrast significantly with the behavior of droplets in these nonlinear flows which are unable to achieve highly deformed steady-state dumbbell shapes owing to their constant surface tension.
An Extensional CPS Transform (Preliminary Report)
Filinski, Andrzej
2001-01-01
We shoe that, in a language wihg general continuation-effects, the syntactic, or intensional, CPS transform is mirrored by a semantic, or extensional, functional term. In other words, form only the observable behavior any direct-style term (possibly containing the usual first-class continuation...... primitives), we can uniformly extract the observable behavior of its CPS counterpart. As a consequence of this result, we show that the computational lambda-calculus is complete for observational equivalence of pure, simply typed lambda-terms in Scheme-like contexts....
An Extensional CPS Transform (Preliminary Report)
Filinski, Andrzej
2001-01-01
We shoe that, in a language wihg general continuation-effects, the syntactic, or intensional, CPS transform is mirrored by a semantic, or extensional, functional term. In other words, form only the observable behavior any direct-style term (possibly containing the usual first-class continuation...... primitives), we can uniformly extract the observable behavior of its CPS counterpart. As a consequence of this result, we show that the computational lambda-calculus is complete for observational equivalence of pure, simply typed lambda-terms in Scheme-like contexts....
Shear and Extensional Flow-Induced Particle Orientation in Polypropylene/Clay Nanocomposites
Burghardt, Wesley; McCready, Erica
2013-03-01
Synchrotron-based in situ x-ray scattering is used to monitor the orientation of dispersed particles in molten polypropylene/clay nanocomposite melts during flow. Nanocomposite samples were prepared via twin screw extrusion processing, and the degree of clay exfoliation assessed in terms of the magnitude of the low frequency enhancement in viscoelasticity. In shear flow, an annular cone and plate flow cell is used which allows measurement of the degree and direction of particle orientation in the flow-gradient (1-2) plane. Samples were also studied in extensional flow, using an SER extensional flow fixture installed in a custom-built convection oven that provides x-ray access. In both shear and extensional flow, only a moderate degree of particle orientation is observed. Extensional flow studies are complicated by (i) the tendency of samples to fail at moderate Hency strain, and (ii) a heterogeneous initial distribution of particle orientation in the SER specimens, prepared by compression molding of extruded pellets of the nanocomposite.
Extensional rheometry with a handheld mobile device
Marshall, Kristin A.; Liedtke, Aleesha M.; Todt, Anika H.; Walker, Travis W.
2017-06-01
The on-site characterization of complex fluids is important for a number of academic and industrial applications. Consequently, a need exists to develop portable rheometers that can provide in the field diagnostics and serve as tools for rapid quality assurance. With the advancement of smartphone technology and the widespread global ownership of smart devices, mobile applications are attractive as platforms for rheological characterization. The present work investigates the use of a smartphone device for the extensional characterization of a series of Boger fluids composed of glycerol/water and poly(ethylene oxide), taking advantage of the increasing high-speed video capabilities (currently up to 240 Hz capture rate at 720p) of smartphone cameras. We report a noticeable difference in the characterization of samples with slight variations in polymer concentration and discuss current device limitations. Potential benefits of a handheld extensional rheometer include its use as a point-of-care diagnostic tool, especially in developing communities, as well as a simple and inexpensive tool for assessing product quality in industry.
Extensional properties of mobile polymer solutions
Tirel, Christophe; Renoult, Marie-Charlotte; Dumouchel, Christophe; Crumeyrolle, Olivier; Lisiecki, Denis; Mutabazi, Innocent
2016-11-01
A deep understanding of the influence of viscoelasticity on the dynamics of liquid flows remains a challenge in the non-Newtonian fluid mechanics field. Previous work has revealed that the addition of minute amount (2.5 part per million) of high molecular weight polymer to water, forming a viscoelastic solution with strong extensional properties, modifies the fission process during droplet snap off with spectacular effects: inhibition of the singularity observed in the reference Newtonian case and formation of a long-lived (milli-second) filament. The measurement of the extensional properties for such mobile polymer solutions is one of the most pressing problem. Here, a global measurement technique, based on the multi-scale analysis of the capillary instability of a free falling jet of a mobile polymer solution, is introduced. The method of analysis allows the characterisation of the jet breakup mechanism from which the relaxation time of the polymer solution can be extracted. One of the advantages of the technique is the simple experiment it requires.
Sung Woo Park; Byung Kwan Oh; Hyo Seon Park
2015-01-01
The safety of a multi-span waler beam subjected simultaneously to a distributed load and deflections at its supports can be secured by limiting the maximum stress of the beam to a specific value to prevent the beam from reaching a limit state for failure or collapse. Despite the fact that the vast majority of accidents on construction sites occur at waler beams in retaining wall systems, no safety monitoring model that can consider deflections at the supports of the beam is available. In this...
A Note on Spector's Quantifier-Free Rule of Extensionality
Kohlenbach, Ulrich
2001-01-01
In this note we show that the so-called weakly extensional arithmetic in all finite types, which is based on a quantifier-free rule of extensionality due to C. Spector and which is of significance in the context of Gödel’s functional interpretation, does not satisfy the deduction theorem...
3D modeling of dual wind-up extensional rheometers
Yu, Kaijia; Román Marín, José Manuel; Rasmussen, Henrik K.
2010-01-01
Fully three-dimensional numerical simulations of a dual wind-up drum rheometer of the Sentmanat Extensional Rheometer (SER; Sentmanat, 2004 [1]) or the Extensional Viscosity Fixture (EVF; Garritano and Berting, 2006 [2]) type have been performed. In the SER and EVF a strip of rectangular shape is...
Extremely Shallow Extensional Faulting Near Geothermal Fields
Hudnut, K. W.; Wei, S.; Donnellan, A.; Fielding, E. J.; Graves, R. W.; Helmberger, D. V.; Liu, Z.; Parker, J. W.; Treiman, J. A.
2013-12-01
Surface faulting has been discovered in association with a shallow extensional M 4.9 earthquake, the source properties of which have also been studied by modeling of broadband seismic data and geodetic imagery. This M 4.9 and also a M 4.6 shallow normal event occurred late in the Brawley Swarm of August 2012, a dominantly strike-slip sequence with events up to M 5.5 (Hauksson et al., SRL 2013 and Wei et al., GRL 2013). The point source waveform inversions reveal normal mechanisms and centroid depths of ~2.5 km for both events, while the modeling of the geodetic data indicates a compatible depth of ~2.0 km. The M 4.9 event had unusually large (~40 cm) and sudden (~1.0 - 1.5 km/sec) slip, considering its extremely shallow depth. The earlier and larger strike-slip events during the Aug. 2012 swarm were on a left-lateral SW-NE oriented vertical planar cross-fault, whereas the M 4.6 and M 4.9 occurred on a SSW-NNE oriented, west-dipping plane. Airborne imagery obtained using Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) revealed a surface fault rupture that was subsequently confirmed and documented in the field in May 2013. A pre-existing but previously un-mapped fault sustained west-down surface slip of up to 18 × 2 cm along breaks extending ~3.5 km along a NNE orientation, and ruptured beneath and under a railroad track and pipeline (without breaking them). UAVSAR and seismological data were used jointly to image the source properties of the M 4.9 earthquake in detail. Typically, the uppermost few kms of right-lateral faults in the Salton Trough exhibit creep, especially after larger earthquakes, as in 1979 and 1987. On this basis, general models of stable sliding within the uppermost few kms have been developed. In this case, however, the joint inversion indicates that seismic energy was radiated by slip of up to 40 cm on a fault plane extending from the surface to a depth of only ~3 km, extending ~4 km along-strike, and dipping ~45° west, with west
Factors That Influence the Extensional Rheological Property of Saliva
Vijay, Amrita; Inui, Taichi; Dodds, Michael; Proctor, Gordon; Carpenter, Guy
2015-01-01
The spinnbarkeit of saliva reflects the ability of saliva to adhere to surfaces within the mouth, thereby serving as a protective role and aiding in lubrication. Therefore, alterations in the extensional rheology of saliva may result in the loss in adhesiveness or the ability to bind onto surfaces. Mucin glycoproteins and their structures are known to be important factors for the extensional rheological properties of saliva. The conformation of mucin depends on factors such as pH and ionic st...
A portable and affordable extensional rheometer for field testing
Hallmark, Bart; Bryan, Matthew; Bosson, Ed; Butler, Simon; Hoier, Tom; Magens, Ole; Pistre, Nicolas; Pratt, Lee; Ward, Betsy-Ann; Wibberley, Sam; Wilson, D. Ian
2016-12-01
Extensional shear testing is often needed to characterise the behaviour of complex fluids found in industry and nature. Traditional extensional rheometers are typically expensive, fragile and heavy and are only suited to making measurements in a laboratory environment. For some applications, it is necessary to make in situ rheological measurements where, for example, fluid properties change rapidly over time or where laboratory facilities are unavailable. This paper reports the development and validation of an inexpensive, lightweight and robust ‘open source’ extensional rheometer, Seymour II. Validation was carried out experimentally and computationally. Measurements on a Newtonian fluid (492 mPa s Brookfield silicone oil) yielded results of 510 ± 51 mPa s; these are comfortably within the range of ±10% which other authors have quoted for extensional techniques using laboratory rheometers. Comparison of the observed filament thinning dynamics to those obtained using computational fluid dynamics (CFD) gave good qualitative agreement. Use of Seymour II at the University of Cambridge Botanic Gardens revealed that the mucilage of the ‘crane flower’, Strelitzia reginae, was a viscoelastic fluid whose extensional response could be described by a two-mode Giesekus equation. Engineering drawings and image analysis code for Seymour II are available for download at the project website, www.seymourII.org/.
Facies composition and scaling relationships of extensional faults in carbonates
Bastesen, Eivind; Braathen, Alvar
2010-05-01
Fault seal evaluations in carbonates are challenged by limited input data. Our analysis of 100 extensional faults in shallow-buried layered carbonate rocks aims to improve forecasting of fault core characteristics in these rocks. We have analyzed the spatial distribution of fault core elements described using a Fault Facies classification scheme; a method specifically developed for 3D fault description and quantification, with application in reservoir modelling. In modelling, the fault envelope is populated with fault facies originating from the host rock, the properties of which (e.g. dimensions, geometry, internal structure, petrophysical properties, and spatial distribution of structural elements) are defined by outcrop data. Empirical data sets were collected from outcrops of extensional faults in fine grained, micro-porosity carbonates from western Sinai (Egypt), Central Spitsbergen (Arctic Norway), and Central Oman (Adam Foothills) which all have experienced maximum burial of 2-3 kilometres and exhibit displacements ranging from 4 centimetres to 400 meters. Key observations include fault core thickness, intrinsic composition and geometry. The studied fault cores display several distinct fault facies and facies associations. Based on geometry, fault cores can be categorised as distributed or localized. Each can be further sub-divided according to the presence of shale smear, carbonate fault rocks and cement/secondary calcite layers. Fault core thickness in carbonate rocks may be controlled by several mechanisms: (1) Mechanical breakdown: Irregularities such as breached relays and asperities are broken down by progressive faulting and fracturing to eventually form a thicker fault rock layer. (2) Layer shearing: Accumulations of shale smear along the fault core. (3) Diagenesis; pressure solution, karstification and precipitation of secondary calcite in the core. Observed fault core thicknesses scatter over three orders of magnitude, with a D/T range of 1:1 to 1
The role of extensional viscosity in frog tongue projection
Noel, Alexis; Wagner, Caroline; McKinley, Gareth; Mendelson, Joe; Hu, David
2014-11-01
Frogs and other amphibians capture insects through high-speed tongue projection, some achieving tongue accelerations of over fifty times gravity. In this experimental study, we investigate how a frog's sticky saliva enables high-speed prey capture. At the Atlanta zoo, we used high-speed video to film the trajectory of frog tongues during prey capture. We have also designed and built a portable extensional rheometer; by following the capillary-driven thinning in the diameter of a thread of saliva we characterize the relaxation time and extensional viscosity and so infer the adhesive force between the frog tongue and prey.
Late Proterozoic extensional collapse in the Arabian-Nubian Shield
Blasband, B.B.; White, S H; Brooijmans, P.; Boorder, H. de; Visser, W.
2000-01-01
A structural and petrological study of the Late Proterozoic rocks in the Wadi Kid area, Sinai, Egypt indicates the presence of an extensional metamorphic core complex in the northern Arabian–Nubian Shield. Gneissic domes throughout the Arabian–Nubian Shield resemble the core complex of the Wadi Kid area and as a result, they are interpreted as extensional metamorphic core complexes. The presence of a widespread phase of extension at the end of the Pan-African period in the Arabian–Nubian Shie...
What sets topographic relief in extensional footwalls?
Densmore, Alexander L.; Dawers, Nancye H.; Gupta, Sanjeev; Guidon, Roman
2005-06-01
We use three large normal fault arrays in the northeastern Basin and Range Province, western United States, to document catchment development and relief production during fault growth. Fault slip and slip rates increase systematically along strike from zero at the fault tips. Catchment relief and across-strike range width both increase as slip accumulates but reach maximum values at a distance of ˜15 km from the fault tips and remain uniform along strike over much of the footwalls. Catchment outlet spacing also increases away from the fault tips but does not reach a uniform value and may vary by a factor of 5 6 along strike. We infer that catchments first elongate in the across-strike direction as slip accumulates and the range half-width increases. Once the half-width reaches its maximum value, continued catchment growth is possible only by along-strike capture, which increases outlet spacing but not relief. The close correspondence between catchment relief and range half-width suggests that geomorphically limited hillslope and channel gradients are achieved within the 15 km tip zone. Thus, the limiting factor in footwall development is the width of the range, which is controlled by two external agents: the geometry and spacing of the major faults, and the elevations of base level on both flanks.
Factors That Influence the Extensional Rheological Property of Saliva.
Vijay, Amrita; Inui, Taichi; Dodds, Michael; Proctor, Gordon; Carpenter, Guy
2015-01-01
The spinnbarkeit of saliva reflects the ability of saliva to adhere to surfaces within the mouth, thereby serving as a protective role and aiding in lubrication. Therefore, alterations in the extensional rheology of saliva may result in the loss in adhesiveness or the ability to bind onto surfaces. Mucin glycoproteins and their structures are known to be important factors for the extensional rheological properties of saliva. The conformation of mucin depends on factors such as pH and ionic strength. Chewing is one of the main stimuli for salivary secretion but creates significant sheer stress on the salivary film which could influence mouthfeel perceptions. The current study investigates the possible factors which affect the extensional rheological properties of saliva by comparing submandibular/sublingual saliva with different oral stimuli within the same group of subjects. Unstimulated and stimulated saliva (chew, smell and taste) salivas were collected primarily from submandibular/sublingual glands. The saliva samples were measured for Spinnbarkeit followed by the measuring mucin, total protein, total calcium and bicarbonate concentrations. The results indicated correlations between rheological properties and mucin/ion concentrations. However, chewing stimulated submandibular/sublingual saliva is shown to have significantly lower Spinnbarkeit, but factors such as mucin, protein and calcium concentrations did not account for this variation. Analysis of the concentration of bicarbonate and pH appears to suggest that it has a prominent effect on extensional rheology of saliva.
Late Proterozoic extensional collapse in the Arabian-Nubian Shield
Blasband, B.B.; White, S.H.; Brooijmans, P.; Boorder, H. de; Visser, W.
2000-01-01
A structural and petrological study of the Late Proterozoic rocks in the Wadi Kid area, Sinai, Egypt indicates the presence of an extensional metamorphic core complex in the northern Arabian–Nubian Shield. Gneissic domes throughout the Arabian–Nubian Shield resemble the core complex of the Wadi Kid
Factors That Influence the Extensional Rheological Property of Saliva.
Amrita Vijay
Full Text Available The spinnbarkeit of saliva reflects the ability of saliva to adhere to surfaces within the mouth, thereby serving as a protective role and aiding in lubrication. Therefore, alterations in the extensional rheology of saliva may result in the loss in adhesiveness or the ability to bind onto surfaces. Mucin glycoproteins and their structures are known to be important factors for the extensional rheological properties of saliva. The conformation of mucin depends on factors such as pH and ionic strength. Chewing is one of the main stimuli for salivary secretion but creates significant sheer stress on the salivary film which could influence mouthfeel perceptions. The current study investigates the possible factors which affect the extensional rheological properties of saliva by comparing submandibular/sublingual saliva with different oral stimuli within the same group of subjects. Unstimulated and stimulated saliva (chew, smell and taste salivas were collected primarily from submandibular/sublingual glands. The saliva samples were measured for Spinnbarkeit followed by the measuring mucin, total protein, total calcium and bicarbonate concentrations. The results indicated correlations between rheological properties and mucin/ion concentrations. However, chewing stimulated submandibular/sublingual saliva is shown to have significantly lower Spinnbarkeit, but factors such as mucin, protein and calcium concentrations did not account for this variation. Analysis of the concentration of bicarbonate and pH appears to suggest that it has a prominent effect on extensional rheology of saliva.
Factors That Influence the Extensional Rheological Property of Saliva
Vijay, Amrita; Inui, Taichi; Dodds, Michael; Proctor, Gordon; Carpenter, Guy
2015-01-01
The spinnbarkeit of saliva reflects the ability of saliva to adhere to surfaces within the mouth, thereby serving as a protective role and aiding in lubrication. Therefore, alterations in the extensional rheology of saliva may result in the loss in adhesiveness or the ability to bind onto surfaces. Mucin glycoproteins and their structures are known to be important factors for the extensional rheological properties of saliva. The conformation of mucin depends on factors such as pH and ionic strength. Chewing is one of the main stimuli for salivary secretion but creates significant sheer stress on the salivary film which could influence mouthfeel perceptions. The current study investigates the possible factors which affect the extensional rheological properties of saliva by comparing submandibular/sublingual saliva with different oral stimuli within the same group of subjects. Unstimulated and stimulated saliva (chew, smell and taste) salivas were collected primarily from submandibular/sublingual glands. The saliva samples were measured for Spinnbarkeit followed by the measuring mucin, total protein, total calcium and bicarbonate concentrations. The results indicated correlations between rheological properties and mucin/ion concentrations. However, chewing stimulated submandibular/sublingual saliva is shown to have significantly lower Spinnbarkeit, but factors such as mucin, protein and calcium concentrations did not account for this variation. Analysis of the concentration of bicarbonate and pH appears to suggest that it has a prominent effect on extensional rheology of saliva. PMID:26305698
Logsdon, Kirk A.
2001-01-01
A fundamental characteristic of fluid is viscosity; that is, the fluid resists forces that cause it to flow. This characteristic, or parameter, is used by manufacturers and end-users to describe the physical properties of a specific material so that they know what to expect when a material, such as a polymer, is processed through an extruder, a film blower, or a fiber-spinning apparatus. Normally, researchers will report a shear viscosity that depends on the rate of an imposed shearing flow. Although this type of characterization is sufficient for some processes, simple shearing experiments do not provide a complete picture of what a processor may expect for all materials. Extensional stretching flows are common in many polymer-processing operations such as extrusion, blow molding, and fiber spinning. Therefore, knowledge of the complete rheological (ability to flow and be deformed) properties of the polymeric fluid being processed is required to accurately predict and account for the flow behavior. In addition, if numerical simulations are ever able to serve as a priori design tools for optimizing polymer processing operations such as those described above, an accurate knowledge of the extensional viscosity of a polymer system and its variation with temperature, concentration, molecular weight, and strain rate is critical.
The importance of flow history in mixed shear and extensional flows
Wagner, Caroline; McKinley, Gareth
2015-11-01
Many complex fluid flows of experimental and academic interest exhibit mixed kinematics with regions of shear and elongation. Examples include flows through planar hyperbolic contractions in microfluidic devices and through porous media or geometric arrays. Through the introduction of a ``flow-type parameter'' α which varies between 0 in pure shear and 1 in pure elongation, the local velocity fields of all such mixed flows can be concisely characterized. It is tempting to then consider the local stress field and interpret the local state of stress in a complex fluid in terms of shearing or extensional material functions. However, the material response of such fluids exhibit a fading memory of the entire deformation history. We consider a dilute solution of Hookean dumbbells and solve the Oldroyd-B model to obtain analytic expressions for the entire stress field in any arbitrary mixed flow of constant strain rate and flow-type parameter α. We then consider a more complex flow for which the shear rate is constant but the flow-type parameter α varies periodically in time (reminiscent of flow through a periodic array or through repeated contractions and expansions). We show that the flow history and kinematic sequencing (in terms of whether the flow was initialized as shearing or extensional) is extremely important in determining the ensuing stress field and rate of dissipated energy in the flow, and can only be ignored in the limit of infinitely slow flow variations.
Pavlis, T. L.; Miller, M.; Serpa, L.
2008-07-01
The term turtleback was first coined to describe the curvilinear fault surfaces that produced a distinctive geomorphic form in the Black Mountains east of Death Valley, and although it was decades before their full significance was appreciated, they remain one of the most distinctive features of the extensional structure of the Death Valley region. Historically the interpretation of the features has varied markedly, and misconceptions about their character continue to abound, including descriptions in popular field guides for the area. It the 1990's, however, the full history of the systems began to be apparent from several key data: 1) the dating of the plutonic assemblage associated with the turtlebacks demonstrated that late Miocene, syn-extensional plutonism was fundamental to their formation; 2) the plutonic assemblage forms an intrusive sheet structurally above the turtlebacks, indicating a tie between much of the high grade metamorphism and Cenozoic plutonism; 3) a modern analog for the syn-extensional plutonism in the Black Mountains was recognized beneath Death Valley with the imaging of a mid-crustal magma body; 4) the Neogene structural history was worked out in the turtlebacks showing that folding of early-formed shear zones formed the turtleback anticlinoria but overprinting by brittle faults produced the final form as they cut obliquely across the older structure; and 5) the pre-extensional structural history was clarified, demonstrating that Mesozoic basement-involved thrust systems are present within the turtlebacks, but have been overprinted by the extensional system. An unresolved issue is the significance of Eocene U-Pb dates for pegmatites within the region, but presumably these relate somehow to the pre-extensional history. Miller and Pavlis (2005; E. Sci. Rev.) reviewed many features of the turtlebacks, and our working model for the region is that the turtlebacks originated as mid-crustal ductile-thrust systems within the Cordilleran fold
Consistency and axiomatization of a natural extensional combinatory logic
蒋颖
1996-01-01
In the light of a question of J. L. Krivine about the consistency of an extensional λ-theory,an extensional combinatory logic ECL+U(G)+RU_∞+ is established, with its consistency model provedtheoretically and it is shown the it is not equivalent to any system of universal axioms. It is expressed bythe theory in first order logic that, for every given group G of order n, there simultaneously exist infinitelymany universal retractions and a surjective n-tuple notion, such that each element of G acts as a permutationof the components of the n-tuple, and as an Ap-automorphism of the model; further each of the universalretractions is invarian under the action of the Ap-automorphisms induced by G The difference between thetheory and that of Krivine is the G need not be a symmetric group.
Tumbling of a Brownian particle in an extensional flow
Plan, Emmanuel Lance Christopher VI Medillo
2016-01-01
The phenomenon of tumbling of microscopic objects is commonly associated with shear flows. We address the question of whether tumbling can also occur in stretching-dominated flows. To answer this, we study the dynamics of a semi-flexible trumbbell in a planar extensional velocity field. We show that the trumbbell undergoes a random tumbling-through-folding motion. The probability distribution of long tumbling times is exponential with a time scale exponentially increasing with the Weissenberg number.
Kinkhabwala, Ali
2013-01-01
The most fundamental problem in statistics is the inference of an unknown probability distribution from a finite number of samples. For a specific observed data set, answers to the following questions would be desirable: (1) Estimation: Which candidate distribution provides the best fit to the observed data?, (2) Goodness-of-fit: How concordant is this distribution with the observed data?, and (3) Uncertainty: How concordant are other candidate distributions with the observed data? A simple unified approach for univariate data that addresses these traditionally distinct statistical notions is presented called "maximum fidelity". Maximum fidelity is a strict frequentist approach that is fundamentally based on model concordance with the observed data. The fidelity statistic is a general information measure based on the coordinate-independent cumulative distribution and critical yet previously neglected symmetry considerations. An approximation for the null distribution of the fidelity allows its direct conversi...
New Constraints on Extensional Environments through Analysis of Teleseisms
Eilon, Zachary Cohen
We apply a variety of teleseismic methodologies to investigate the upper mantle structure in extensional environments. Using a body wave dataset collected from a regional deployment in the Woodlark Rift, Papua New Guinea, we image anisotropic velocity structure of a rapidly extending rift on the cusp of continental breakup. In the process, we develop a technique for azimuthal anisotropy tomography that is generally applicable to regions of relatively simple anisotropic structure. The Cascadia Initiative ocean bottom seismometer (OBS) deployment provides coverage of an entire oceanic plate in unprecedented detail; we measure attenuation and velocities of teleseisms to characterize the temperature and melt structure from ridge to trench. Our study of shear wave splitting reveals strong azimuthal anisotropy within the Woodlark Rift with fairly uniform fast directions parallel to extension. This observation differs markedly from other continental rifts and resembles the pattern seen at mid-ocean ridges. This phenomenon is best explained by extension-related strain causing preferential alignment of mantle olivine. We develop a simple relationship that links total extension to predicted splitting, and show that it explains the apparent dichotomy in rifts' anisotropy. Finite frequency tomography using a dataset of teleseismic P- and S-wave differential travel times reveals the upper mantle velocity structure of the Woodlark Rift. A well developed slow rift axis extending >250 km along strike from the adjacent seafloor spreading centers demonstrates the removal of mantle lithosphere prior to complete crustal breakup. We argue that the majority of this rift is melt-poor, in agreement with geochemical results. A large temperature gradient arises from the juxtaposition of upwelled axial asthenosphere with a previously unidentified cold structure north of the rift that hosts well located intermediate depth earthquakes. Localization of upper mantle extension is apparent from
Szopinski, Daniel; Handge, Ulrich A; Kulicke, Werner-Michael; Abetz, Volker; Luinstra, Gerrit A
2016-01-20
The extensional rheological properties of aqueous ionic carboxymethyl hydroxypropyl guar gum (CMHPG) and non-ionic hydroxypropyl guar gum (HPG) solutions between the semi-dilute solution state and the concentrated network solution state were investigated by capillary breakup elongational rheometry (CaBER). Carboxymethylated guar gum derivatives show an instable filament formation in deionized water. The ratio of elongational relaxation time λE over the shear relaxation time λS follows a power law of λE/λS∼(c · [η])(-2). The difference of the relaxation times in shear and elongation can be related to the loss of entanglements and superstructures in elongational flows at higher strains.
ZHENG; Yadong
2005-01-01
The Sino-Mongolian border areas underwent two important tectonic events during Mesozoic time after late Paleozoic orogeny: a late Triassic to earlier Jurassic contractional event that resulted in a large-scale south-vergent thrust during the orogeny and a late Jurassic-earlier Cretaceous extensional event in a north-south direction that formed a metamorphic core complex. The kinematic and dynamic analyses show that the thrust sheet moved southwards with a kinematic vorticity number of ca. -0.10 and sub-horizontal maximum compressive stress axis that belongs to a contraction-thickening shear. The upper plate of the late-orogenic detachment relatively moved in a 165°direction. The average kinematic vorticity in its earlier stage was 0.74 that belongs to simple shear dominated shearing and related to the maximum compressive stress axes dipping at ～66°, while the later average kinematic vorticity was ～0.55°that belongs to pure shear dominated shearing with sub-vertical maximum compressive stress axes. This suggests that the thrusting led to the crust thickened and the lower plate rocks that were originally located in the upper crust depressed through a brittle-ductile transition zone into the lower crust and became warmer. The heated rocks trended to uplift since their increasing volume and decreasing density while the loading of the upper-plate rocks increased due to the structural thickening. Under the combined effect of the loading and the thermal-uplifting, the ductile shear zone in between increased in its component of vertical pure shear. Once its pure-shear component exceeded its simple-shear one the ductile shear zone became an extension-thinned shear zone. This progressive transitional process reflects internal and essential temporal and spatial relationships: the extensional factor nucleated during the crust thickening by thrusting and increase of the extensional factor finally led to late-orogenic collapse.
王涛; 郑亚东; 李天兵; 高永军; 马铭波
2002-01-01
It is generally considered that granitic plutons are forcefully emplaced in a compressional setting and permissively emplaced in an extensional setting. This paper, however, shows that syn-kinematic (extensional) elliptic granitic plutons in the Yagan-Onch Hayrhan metamorphic core complex (MCC) have relatively strong forceful emplacement, which are indicated by (1) concentric distribution of the rock units, (2) a strain pattern with strong strains on the margins and low strains at the centre of a pluton, and particularly (3) syn-emplacement shortening of the host rocks within the aureole. The strain analysis for the host rocks shows that the host-rock ductile shortening, I.e. Forceful emplacement, provides about 16?24% of the emplacement space for the present plutons. All these suggest that forceful emplacement occurs not only in a compressional tectonic setting, but also in an extensional setting. This study further demonstrates the significance of the multiple emplacement of granitic plutons and provides new information about the causality between granitic magmatism and the formation of the MCC and its dynamics.
Extensional Collapse Situations I: non-termination and unrecoverable errors
Bucciarelli, Antonio
2011-01-01
We consider a simple model of higher order, functional computation over the booleans. Then, we enrich the model in order to encompass non-termination and unrecoverable errors, taken separately or jointly. We show that the models so defined form a lattice when ordered by the extensional collapse situation relation, introduced in order to compare models with respect to the amount of "intensional information" that they provide on computation. The proofs are carried out by exhibiting suitable applied {\\lambda}-calculi, and by exploiting the fundamental lemma of logical relations.
A new look at extensional rheology of low-density polyethylene
Huang, Qian; Mangnus, Marc; Alvarez, Nicolas J.
2016-01-01
The nonlinear rheology of three selected commercial low-density polyethylenes (LDPE) is measured in uniaxial extensional flow. The measurements are performed using three different devices including an extensional viscosity fixture (EVF), a homemade filament stretching rheometer (DTU-FSR) and a co......The nonlinear rheology of three selected commercial low-density polyethylenes (LDPE) is measured in uniaxial extensional flow. The measurements are performed using three different devices including an extensional viscosity fixture (EVF), a homemade filament stretching rheometer (DTU....... With the capability of the filament stretching rheometers, we show that LDPEs with quite different linear viscoelastic properties can have very similar steady extensional viscosity. This points to the potential for independently controlling shear and extensional rheology in certain rate ranges....
Dynamics of Star Polymers in Fast Extensional Flow and Stress Relaxation
Huang, Qian; Agostini, Serena; Hengeller, Ludovica;
2016-01-01
We confirm the observation from Ianniruberto and Marrucci [ Macromolecules 2013, 46, 267-275 ] that entangled melts of branched polystyrenes behave like linear polystyrenes in the steady state of fast extensional flow, by measuring a linear, an asymmetric star, and a symmetric star polystyrene...... with the same span molecular weight (180 kg/mol). We show that all three melts reach the same extensional steady-state viscosity in fast extensional flow (faster than the inverse Rouse time). We further measure stress relaxation following steady extensional flow for the three melts. We show that initially...
Kiatgamolchai, S
2000-01-01
gamma has the bowl shape with the minimum at x approx 0.25-0.3. These characteristics suggest a possible influence of alloy disorder scattering. The mobilities and activation energies of the carriers in the boron-doped cap vary between samples and this is believed to be due to boron-spike near the Si/Si-substrate interface, in some samples. The source of electron-like carrier is presently unknown. Magnetotransport properties of modulation-doped p-type Si sub 1 sub - sub x Ge sub x /Si and Si sub 1 sub - sub x Ge sub x /Si sub 1 sub - sub y Ge sub y heterostructures were studied, in the magnetic field range 0-12 T, and in the temperature range 0.35-300 K. The experimental data within the classical regime have been analysed by mobility spectrum analysis, in order to separate the influences of different parallel conduction paths. A new method of mobility spectrum analysis has been developed by the based on the concept of maximum-entropy, and this computation has been shown to overcome several drawbacks or limita...
Marangoni Effects of a Drop in an Extensional Flow: The Role of Surfactant Physical Chemistry
Stebe, Kathleen J.; Balasubramaniam, R. (Technical Monitor)
2002-01-01
While the changes in stresses caused by surfactant adsorption on non-deforming interfaces have been fairly well established, prior to this work, there were few studies addressing how surfactants alter stresses on strongly deforming interfaces. We chose the model problem of a drop in a uniaxial extensional flow to study these stress conditions To model surfactant effects at fluid interfaces, a proper description of the dependence of the surface tension on surface concentration, the surface equation of state, is required. We have adopted a surface equation of state that accounts for the maximum coverage limit; that is, because surfactants have a finite cross sectional area, there is an upper bound to the amount of surfactant that can adsorb in a monolayer. The surface tension reduces strongly only when this maximum coverage is approached. Since the Marangoni stresses go as the derivative of the surface equation of state times the surface concentration gradient, the non-linear equation of state determines both the effect of surfactants in the normal stress jump, (which is balanced by the product of the mean curvature of the interface times the surface tension), and the tangential stress jump, which is balanced by Marangoni stresses. First, the effects of surface coverage and intermolecular interactions among surfactants which drive aggregation of surfactants in the interface were studied. (see Pawar and Stebe, Physics of Fluids).
Extensional unroofing of the Veliki Jastrebac dome (Serbia
Marović Milun
2007-01-01
Full Text Available This paper presents the basic structural elements of the dome of Veliki Jastrebac, as well as the chronology and mechanisms of the deformational events responsible for its formation. It was determined that the dome of Veliki Jastrebac consists of two large sequences which are, in the vertical section, in the inverse position. The lower part is made of Late Cretaceous and Cretaceous-Palaeogene low-grade to medium-grade metamorphic rocks, which are intruded by Paleogene granitoid (probably the Vardar Zone, which are covered with a large overthrust consisting metamorphics of the Serbian-Macedonian Mass. The low-grade to medium-grade metamorphosed complex of Veliki Jastrebac, with the granitoid, represents a metamorphic core complex, exhumed by mechanisms of extensional tectonics in the Paleogene.
Modifying the pom-pom model for extensional viscosity overshoots
Hawke, L. D. G.; Huang, Qian; Hassager, Ole;
2015-01-01
We have developed a variant of the pom-pom model that qualitatively describes two surprising features recently observed in filament stretching rheometer experiments of uniaxial extensional flow of industrial branched polymer resins: (i) Overshoots of the transient stress during steady flow and (ii......) strongly accelerated stress relaxation upon cessation of the flow beyond the overshoot. Within the context of our model, these overshoots originate from entanglement stripping (ES) during the processes of normal chain retraction and branch point withdrawal. We demonstrate that, for a single mode...... a reasonable, but not perfect, fit to the data. With regard the stress relaxation after (kinematically) steady flow, we demonstrate that the differential version of tube orientation dynamics in the original pom-pom model performs anomalously. We discuss the reasons for this and suggest a suitable alternative....
Costanzo, Salvatore; Huang, Qian; Ianniruberto, Giovanni
2016-01-01
We investigate the nonlinear shear and uniaxial extensional rheology of entangled polystyrene (PS) melts and solutions having the same number Z of entanglements, hence identical linear viscoelasticity. While experiments in extensional flows confirm that PS melts and solutions with the same Z behave...
Anderson, R. Ernest; Beard, Sue; Mankinen, Edward A.; Hillhouse, John W.
2013-01-01
For more than two decades, the paradigm of large-magnitude (~250 km), northwest-directed (~N70°W) Neogene extensional lengthening between the Colorado Plateau and Sierra Nevada at the approximate latitude of Las Vegas has remained largely unchallenged, as has the notion that the strain integrates with coeval strains in adjacent regions and with plate-boundary strain. The paradigm depends on poorly constrained interconnectedness of extreme-case lengthening estimated at scattered localities within the region. Here we evaluate the soundness of the inferred strain interconnectedness over an area reaching 600 km southwest from Beaver, Utah, to Barstow, California, and conclude that lengthening is overestimated in most areas and, even if the estimates are valid, lengthening is not interconnected in a way that allows for published versions of province-wide summations.We summarize Neogene strike slip in 13 areas distributed from central Utah to Lake Mead. In general, left-sense shear and associated structures define a broad zone of translation approximately parallel to the eastern boundary of the Basin and Range against the Colorado Plateau, a zone we refer to as the Hingeline shear zone. Areas of steep-axis rotation (ranging to 2500 km2) record N-S shortening rather than unevenly distributed lengthening. In most cases, the rotational shortening and extension-parallel folds and thrusts are coupled to, or absorb, strike slip, thus providing valuable insight into how the discontinuous strike-slip faults are simply parts of a broad zone of continuous strain. The discontinuous nature of strike slip and the complex mixture of extensional, contractional, and steep-axis rotational structures in the Hingeline shear zone are similar to those in the Walker Lane belt in the west part of the Basin and Range, and, together, the two record southward displacement of the central and northern Basin and Range relative to the adjacent Colorado Plateau. Understanding this province
Extensional Relaxation Times and Pinch-off Dynamics of Dilute Polymer Solutions
Dinic, Jelena; Zhang, Yiran; Jimenez, Leidy; Sharma, Vivek
2015-11-01
We show that visualization and analysis of capillary-driven thinning and pinch-off dynamics of the columnar neck in an asymmetric liquid bridge created by dripping-onto-substrate can be used for characterizing the extensional rheology of complex fluids. Using a particular example of dilute, aqueous PEO solutions, we show the measurement of both the extensional relaxation time and extensional viscosity of weakly elastic, polymeric complex fluids with low shear viscosity ηsessile drop to a nozzle is detected optically, and the extensional response for viscoelastic fluids is characterized by analyzing their elastocapillary self-thinning, we refer to this technique as optically-detected elastocapillary self-thinning dripping-onto-substrate (ODES-DOS) extensional rheometry.
Salt diapirs in the Dead Sea basin and their relationship to Quaternary extensional tectonics
Al-Zoubi, A.; ten Brink, U.S.
2001-01-01
Regional extension of a brittle overburden and underlying salt causes differential loading that is thought to initiate the rise of reactive diapirs below and through regions of thin overburden. We present a modern example of a large salt diapir in the Dead Sea pull-apart basin, the Lisan diapir, which we believe was formed during the Quaternary due to basin transtension and subsidence. Using newly released seismic data that are correlated to several deep wells, we determine the size of the diapir to be 13 x 10 km. its maximum depth 7.2 km. and its roof 125 m below the surface. From seismic stratigraphy, we infer that the diapir started rising during the early to middle Pleistocene as this section of the basin underwater rapid subsidence and significant extension of the overburden. During the middle to late Pleistocene, the diapir pierced through the extensionally thinned overburden, as indicated by rim synclines, which attest to rapid salt withdrawal from the surrounding regions. Slight positive topography above the diapir and shallow folded horizons indicate that it is still rising intermittently. The smaller Sedom diapir, exposed along the western bounding fault of the basin is presently rising and forms a 200 m-high ridge. Its initiation is explained by localized E-W extension due monoclinal draping over the edge of a rapidly subsiding basin during the early to middle Pleistocene, and its continued rise by lateral squeezing due to continued rotation of the Amazyahu diagonal fault. ?? 2001 Elsevier Science Ltd. All rights reserved.
Extensional Tectonic Regime of Garut Basin based on Magnetotelluric Analysis
Lina Handayani
2014-07-01
Full Text Available DOI: 10.17014/ijog.v8i3.162Garut Basin are is part of Bandung-Garut Greater Basin (Bandung Zone characterized by a large basin surrounded by mountain ranges. Active volcanoes had distributed their material as pyroclastic deposits around the outer border of the zone and as lava flow deposit separating the two basins. Bouguer gravity anomaly data had also indicated the presence of several low anomaly closures at about the area of Bandung and Garut Basins that were surrounded by high gravity anomaly zones. Two magnetotelluric surveys were completed to acquire the subsurface model that might explain the tectonic evolution of studied area. The first stage was characterized sby the presence of horst - graben structures that might imply an extensional regime of the area. The next stage of evolutionwas indicated by the horizontal layering correlated to the relative non-active tectonic. In addition, a most recent structure that appeared near the surface might suggest a possible extension force as the current stage.
Peeling flexible beams in viscous fluids: Rigidity and extensional compliance
Dhong, Charles; Fréchette, Joëlle
2017-01-01
We describe small angle peeling measurements in completely submerged environments to study the coupling between viscous forces and the mechanical properties of the plates being peeled. During the experiments, the plates resist motion because of lubrication forces while van der Waals forces between the plates and the static surface are negligible. In particular, we study the role played by flexural rigidity in the force-displacement curves and in the energy release rate. We show that the coupling between the viscous forces and the flexural rigidity of the plates dictates the shape and magnitude of the force-displacement curves. We develop simple scaling relationships that combine the lubrication forces with an Euler-Bernoulli beam to extract how the peak force and energy release rates depend on the ratio between rigidity and viscosity, and show good agreement between the predictions and experimental results. We also show that increasing the extensional compliance leads to a decrease in both the force-displacement curve and in the energy release rate. We then demonstrate that this reduction can be interpreted in terms of a stress decay length.
Saha, Debashish; Soos, Miroslav; Lüthi, Beat; Holzner, Markus; Liberzon, Alex; Babler, Matthaus U; Kinzelbach, Wolfgang
2014-12-09
Aggregates prepared under fully destabilized conditions by the action of Brownian motion were exposed to an extensional flow generated at the entrance of a sudden contraction. Two noninvasive techniques were used to monitor their breakup process [i.e. light scattering and three-dimensional (3D) particle tracking velocimetry (3D-PTV)]. While the first one can be used to measure the size and the morphology of formed fragments after the breakage event, the latter is capable of resolving trajectories of individual aggregates up to the breakage point as well as the trajectories of formed fragments. Furthermore, measured velocity gradients were used to determine the local hydrodynamic conditions at the breakage point. All this information was combined to experimentally determine for the first time the breakage rate of individual aggregates, given in the form of a size reduction rate K(R), as a function of the applied strain rate, as well as the properties of the formed fragments (i.e., the number of formed fragments and the size ratio between the largest fragment and the original aggregate). It was found that K(R) scales with the applied strain rate according to a power law with the slope being dependent on the initial fractal dimension only, while the obtained data indicates a linear dependency of K(R) with the initial aggregate size. Furthermore, the probability distribution function (PDF) of the number of formed fragments and the PDF of the size ratio between the largest fragment and the original aggregate indicate that breakage will result with high probability (75%) in the formation of two to three fragments with a rather asymmetric ratio of sizes of about 0.8. The obtained results are well in agreement with the results from the numerical simulations published in the literature.
The Maximum Effective Moment Criterion (MEMC) and Its Implications in Structural Geology
无
2006-01-01
The Mohr-Coulomb criterion has been widely used to explain formation of fractures.However, it fails to explain large strain deformation that widely occurs in nature. There is presently a σ1-σ3 represents the yield strength of the related rock, L is a unit length and α is the angle between σ1and deformation bands. This criterion demonstrates that the maximum value appears at angles of ±54.7° to σ1 and there is a slight difference in the moment in the range of 55°±10°. The range covers the whole observations available from nature and experiments. Its major implications include: (1) it can be used to determine the stress state when the related deformation features formed; (2) it provides a new approach to determine the Wk of the related ductile shear zone if only the ratio of the vorticity and strain rate remains fixed; (3) It can be used to explain (a) the obtuse angle in the contraction direction of conjugate kink-bands and extensional crenulation cleavages, (b) formation of low-angle normal faults and high-angle reverse faults, (c) lozenge ductile shear zones in basement terranes, (d) some crocodile structures in seismic profiles and (e) detachment folds in foreland basins.
Tectonic and gravity extensional collapses in overpressured cohesive and frictional wedges
Yuan, X. P.; Leroy, Y. M.; Maillot, B.
2015-03-01
Two modes of extensional collapse in a cohesive and frictional wedge of arbitrary topography, finite extent, and resting on an inclined weak décollement are examined by analytical means. The first mode consists of the gravitational collapse by the action of a half-graben, rooting on the décollement and pushing seaward the frontal part of the wedge. The second mode results from the tectonics extension at the back wall with a similar half-graben kinematics and the landward sliding of the rear part of the wedge. The predictions of the maximum strength theorem, equivalent to the kinematic approach of limit analysis and based on these two collapse mechanisms, not only match exactly the solutions of the critical Coulomb wedge theory, once properly amended, but generalizes them in several aspects: wedge of finite size, composed of cohesive material and of arbitrary topography. This generalization is advantageous to progress in our understanding of many laboratory experiments and field cases. For example, it is claimed from analytical results validated by experiments that the stability transition for a cohesive, triangular wedge occurs with the activation of the maximum length of the décollement. It is shown that the details of the topography, for the particular example of the Mejillones peninsula (North Chile) is, however, responsible for the selection of a short length-scale, dynamic instability corresponding to a frontal gravitational instability. A reasonable amount of cohesion is sufficient for the pressures proposed in the literature to correspond to a stability transition and not with a dynamically unstable state.
Jaishankar, Aditya; Haward, Simon; Hall, Nancy Rabel; Magee, Kevin; McKinley, Gareth
2012-01-01
The primary objective of SHERE II is to study the effect of torsional preshear on the subsequent extensional behavior of filled viscoelastic suspensions. Microgravity environment eliminates gravitational sagging that makes Earth-based experiments of extensional rheology challenging. Experiments may serve as an idealized model system to study the properties of lunar regolith-polymeric binder based construction materials. Filled polymeric suspensions are ubiquitous in foods, cosmetics, detergents, biomedical materials, etc.
What do we learn from extensional tectonics in the Western Alps?
Sue, C.; Champagnac, J.-D.
2009-04-01
The Western Alps' active tectonics are characterized by ongoing widespread extension in the highest parts of the belt and transpressive/compressive tectonics along its borders (Sue et al., 1999; Delacou et al., 2004). We examine these contrasting tectonic regimes, as well as the role of erosional processes, using a multidisciplinary approach including seismotectonics, numerical modelling, GPS, morphotectonics, fieldwork, and brittle deformation analysis. Extension appears to be the dominant process in the present-day tectonic activity in the Western Alps, affecting its internal areas all along the arc. Shortening, in contrast, is limited to small areas located along at the outer borders of the chain. Strike-slip is observed throughout the Alpine realm and in the foreland. The stress-orientation pattern is radial for σ3 in the inner, extensional zones, and for σ1 in the outer, transcurrent/tranpressional ones. Extensional areas can be correlated with the parts of the belt with the thickest crust. Quantification of seismic strain in tectonically homogeneous areas shows that only 10 to 20% of the geodesy-documented deformation can be explained by the Alpine seismicity. We show that Alpine active tectonics are ruled by buoyancy forces rather than ongoing shortening along the Alpine Europe/Adria collision zone. Numerical modeling corroborates this interpretation. The Neogene extensional structures in the Alps formed under increasingly brittle conditions. A synthesis of paleostress tensors for the internal parts of the West-Alpine arc documents major orogen-parallel extension with a continuous change in σ3 directions from ENE-WSW in the Simplon area, to N-S in the Vanoise area and to NNW-SSE in the Briançon area (Champagnac et al., 2006). Minor orogen-perpendicular extension increases from N to S. This second signal correlates with present-day geodynamics as revealed by focal-plane mechanisms analysis. The orogen-parallel extension could be related to the opening of
Wang, Junxia; Cao, Changlin; Yu, Dingshan; Chen, Xudong
2017-05-01
In this paper, the effect of varying extensional-shear couple loading on deformation and stress response of Carbon Nanotubes/ ultra-high molecular weight polyethylene (CNTs/UHMWPE) composites was investigated using finite element numerical simulation, with expect to improve the manufacturing process of UHMWPE-based composites with reduced stress and lower distortion. When applying pure extensional loading and pure X-Y shear loading, it was found that the risk of a structural breakage greatly rises. For identifying the coupling between extensional and shear loading, distinct generations of force loading were defined by adjusting the magnitude of extensional loading and X-Y shear loading. It was shown that with the decrement of X-Y shear loading the deformation decreases obviously where the maximal Mises stress in Z-direction at 0.45 m distance is in the range from 24 to 10 MPa and the maximal shear stress at 0.61 m distance is within the range from 0.9 to 0.3 MPa. In addition, all the stresses determined were clearly below the yield strength of CNTs/UHMWPE composites under extensional-shear couple loading.
Capillary break-up, gelation and extensional rheology of hydrophobically modified cellulose ethers
Sharma, Vivek; Haward, Simon; Pessinet, Olivia; Soderlund, Asa; Threlfall-Holmes, Phil; McKinley, Gareth
2012-02-01
Cellulose derivatives containing associating hydrophobic groups along their hydrophilic polysaccharide backbone are used extensively in the formulations for inks, water-borne paints, food, nasal sprays, cosmetics, insecticides, fertilizers and bio-assays to control the rheology and processing behavior of multi-component dispersions. These complex dispersions are processed and used over a broad range of shear and extensional rates. The presence of hydrophobic stickers influences the linear and nonlinear rheology of cellulose ether solutions. In this talk, we systematically contrast the difference in the shear and extensional rheology of a cellulose ether: ethy-hydroxyethyl-cellulose (EHEC) and its hydrophobically-modified analog (HMEHEC) using microfluidic shear rheometry at deformation rates up to 10^6 inverse seconds, cross-slot flow extensional rheometry and capillary break-up during jetting as a rheometric technique. Additionally, we provide a constitutive model based on fractional calculus to describe the physical gelation in HMEHEC solutions.
Strain rate orientations near the Coso Geothermal Field
Ogasa, N. T.; Kaven, J. O.; Barbour, A. J.; von Huene, R.
2016-12-01
Many geothermal reservoirs derive their sustained capacity for heat exchange in large part due to continuous deformation of preexisting faults and fractures that permit permeability to be maintained. Similarly, enhanced geothermal systems rely on the creation of suitable permeability from fracture and faults networks to be viable. Stress measurements from boreholes or earthquake source mechanisms are commonly used to infer the tectonic conditions that drive deformation, but here we show that geodetic data can also be used. Specifically, we quantify variations in the horizontal strain rate tensor in the area surrounding the Coso Geothermal Field (CGF) by analyzing more than two decades of high accuracy differential GPS data from a network of 14 stations from the University of Nevada Reno Geodetic Laboratory. To handle offsets in the data, from equipment changes and coseismic deformation, we segment the data, perform a piecewise linear fit and take the average of each segment's strain rate to determine secular velocities at each station. With respect to North America, all stations tend to travel northwest at velocities ranging from 1 to 10 mm/yr. The nearest station to CGF shows anomalous motion compared to regional stations, which otherwise show a coherent increase in network velocity from the northeast to the southwest. We determine strain rates via linear approximation using GPS velocities in Cartesian reference frame due to the small area of our network. Principal strain rate components derived from this inversion show maximum extensional strain rates of 30 nanostrain/a occur at N87W with compressional strain rates of 37nanostrain/a at N3E. These results generally align with previous stress measurements from borehole breakouts, which indicate the least compressive horizontal principal stress is east-west oriented, and indicative of the basin and range tectonic setting. Our results suggest that the CGF represents an anomaly in the crustal deformation field, which
Shear and extensional properties of bread doughs affected by their minor components
Rouillé, J.; Valle, Della G.; Lefebvre, J.; Sliwinski, E.L.; Vliet, van T.
2005-01-01
The importance of the soluble fraction in flour in determining the rheological properties of dough subjected to large deformations and its possible consequence for breadmaking performance was investigated by measuring shear and extensional viscosities of native wheat flour and reconstituted doughs
Bridging the Gap between Polymer Melts and Solutions in Extensional Rheology
Huang, Qian; Hengeller, Ludovica; Alvarez, Nicolas J.
2015-01-01
and polymer melts. We compare the nonlinear extensional rheology of a series of polystyrene solutions with wide concentration range between 10% and 100% (melt) in order to determine the key missing physics that can account for dilution effects. All the solutions studied have the same number of entanglements...
Extensional rheology of entangled polystyrene solutions suggests importance of nematic interactions
Huang, Qian; Javier Alvarez, Nicolas; Matsumiya, Yumi
polymer solutions in extensional flow. We prepared three polystyrene (PS) solutions with identical concentrations of the same PS sample (with the molecular weight M = 545k), but diluted with three different solvents, oligomeric styrene (OS) with M = 1k, 2k, and 4k. The three solutions have exactly...
The dynamics of cylindrical samples in dual wind-up extensional rheometers
Yu, Kaijia; Rasmussen, Henrik K.; Marín, Jose Manuel Román
2011-01-01
Numerical computations of the extension of circular cylindrical shaped samples in a dual wind-up drum rheometer of Sentmanat extensional rheometer type M. L. Sentmanat, Rheol. Acta 43, 657 (2004); R. Garritano and H. Berting, US Patent No. 7,096,728 (08/29/2006) are presented. These time-dependen...
Rasmussen, Henrik K.; Huang, Qian
2014-01-01
We have derived a constitutive equation to explain the extensional dynamics of oligomer-diluted monodisperse polymers, if the length of the diluent has at least two Kuhn steps. These polymer systems have a flow dynamics which distinguish from pure monodisperse melts and solutions thereof, if the ...
Cagliani, Alberto; Kosaka, Priscila; Tamayo, Javier;
2012-01-01
We have fabricated an ultrasensitive nanomechanical resonator based on the extensional vibration mode to weigh the adsorbed water on self-assembled monolayers of DNA as a function of the relative humidity. The water adsorption isotherms provide the number of adsorbed water molecules per nucleotid...
The missing link between the extensional dynamics of polymer melts and solutions
Rasmussen, Henrik K.; Huang, Qian
2014-01-01
Based on extensional viscosities measured on narrow molecular weight distributed (NMMD) polystyrenes and polystyrene oligomer dilutions thereof, we discuss the relation between the flow physics of polymer solutions and melts. A polymer solution is here characterized as a dilution where the diluen...
Maximum Autocorrelation Factorial Kriging
Nielsen, Allan Aasbjerg; Conradsen, Knut; Pedersen, John L.
2000-01-01
This paper describes maximum autocorrelation factor (MAF) analysis, maximum autocorrelation factorial kriging, and its application to irregularly sampled stream sediment geochemical data from South Greenland. Kriged MAF images are compared with kriged images of varimax rotated factors from...
Numerical analysis of extensional flow through the pharyngeal duct
Preciado-Méndez, M.; Salinas-Vázquez, M.; Vicente, W.; Brito-de la Fuente, E.; Ascanio, G.
2017-01-01
The flow through the pharynx from the glossopalatal junction (GPJ) to the upper esophageal sphincter (UES) has been numerically investigated with a non-Newtonian fluid obeying the power-law with similar rheological indices to a contrast medium used in videofluroscopy. For that purpose, a three-dimensional model of the transport of food bolus along the pharynx has been proposed using the immersed boundaries method, which allow representing the shape of the pharynx using Cartesian grids. The pharyngeal wall has been considered to be an elastic membrane. Flow fields in terms of the axial velocity, pressure, shear rate and strain rate were obtained. Results show that the highest velocity concentrates in the central stream as the fluid enters into the pharynx. In addition, as the flow quits the pharynx, a recirculation zone appears inside the cavity, resulting in low velocity zone, which increases with the coefficient of elasticity. A strong dependence on the coefficient of elasticity was observed on the pressure fields; so that as such a coefficient increases, the pressure in the pharyngeal wall will increase. It has been also observed that the bolus head travels faster than the bolus tail, which indicates that the bolus is not only subjected to shear but also to elongation. Results from this work can be further used for a rheological characterization (shear and extension) of oral nutritional supplements for patients suffering from swallowing disorders.
Extensional Flow-Induced Dynamic Phase Transitions in Isotactic Polypropylene.
Ju, Jianzhu; Wang, Zhen; Su, Fengmei; Ji, Youxin; Yang, Haoran; Chang, Jiarui; Ali, Sarmad; Li, Xiangyang; Li, Liangbin
2016-09-01
With a combination of fast extension rheometer and in situ synchrotron radiation ultra-fast small- and wide-angle X-ray scattering, flow-induced crystallization (FIC) of isotactic polypropylene (iPP) is studied at temperatures below and above the melting point of α crystals (Tmα). A flow phase diagram of iPP is constructed in strain rate-temperature space, composing of melt, non-crystalline shish, α and α&β coexistence regions, based on which the kinetic and dynamic competitions among these four phases are discussed. Above Tmα , imposing strong flow reverses thermodynamic stabilities of the disordered melt and the ordered phases, leading to the occurrence of FIC of β and α crystals as a dynamic phase transition. Either increasing temperature or stain rate favors the competiveness of the metastable β over the stable α crystals, which is attributed to kinetic rate rather than thermodynamic stability. The violent competitions among four phases near the boundary of crystal-melt may frustrate crystallization and result in the non-crystalline shish winning out.
Fernández, Rubén Díez; Pereira, Manuel Francisco
2016-11-01
The late Paleozoic collision between Gondwana and Laurussia resulted in the polyphase deformation and magmatism that characterizes the Iberian Massif of the Variscan orogen. In the Central Iberian Zone, initial continental thickening (D1; folding and thrusting) was followed by extensional orogenic collapse (D2) responsible for the exhumation of high-grade rocks coeval to the emplacement of granitoids. This study presents a tectonometamorphic analysis of the Trancoso-Pinhel region (Central Iberian Zone) to explain the processes in place during the transition from an extension-dominated state (D2) to a compression-dominated one (D3). We reveal the existence of low-dipping D2 extensional structures later affected by several pulses of subhorizontal shortening, each of them typified by upright folds and strike-slip shearing (D3, D4 and D5, as identified by superimposition of structures). The D2 Pinhel extensional shear zone separates a low-grade domain from an underlying high-grade domain, and it contributed to the thermal reequilibration of the orogen by facilitating heat advection from lower parts of the crust, crustal thinning, decompression melting, and magma intrusion. Progressive lessening of the gravitational disequilibrium carried out by this D2 shear zone led to a switch from subhorizontal extension to compression and the eventual cessation and capture of the Pinhel shear zone by strike-slip tectonics during renewed crustal shortening. High-grade domains of the Pinhel shear zone were folded together with low-grade domains to define the current upright folded structure of the Trancoso-Pinhel region, the D3 Tamames-Marofa-Sátão synform. New dating of syn-orogenic granitoids (SHRIMP Usbnd Pb zircon dating) intruding the Pinhel shear zone, together with the already published ages of early extensional fabrics constrain the functioning of this shear zone to ca. 331-311 Ma, with maximum tectonomagmatic activity at ca. 321-317 Ma. The capture and apparent cessation
Shabbir, Aamir; Huang, Qian; P. Baeza, Guilhem
2017-01-01
(ethylene oxide) (PEO) along the backbone in the coionomer with poly ( tetramethylene glycol) PTMO, increases the maximum Hencky strain at fracture thus adding ductility to the brittle PTMO-Na ionomer. As a result, the coionomer deforms much more compared to PTMO-Na but both fracture eventually...... to formation of strong ionic aggre-gates. These ionomer melts exhibit viscoelastic properties similar to well-entangled melts with an extended rubbery plateau. To evaluate the effects of nonlinear deforma-tion, the rheology of these ionomers was investigated using uniaxial extension and shear. The measurements...
Zhang, Jianguo; Jiang, Zaixing; Gierlowski-Kordesch, Elizabeth; Xian, Benzhong; Li, Zhenpeng; Wang, Siqi; Wang, Xiabin
2017-03-01
It has been known that both extensional and transtensional tectonics commonly trigger a one-cycle evolution of lake sediments, but lake-cycle development co-controlled by extensional and transtensional tectonics still need identification. Here we report a double-cycle of lake sediments formed in extensional to transtensional phases in the Paleogene Nanpu Sag of the Bohai Bay Basin, China. The sag successively experienced five phases of lake-type evolution, characterized by: 1) overfilled, 2) balanced-fill, 3) overfilled, 4) balanced-fill, and 5) overfilled. Extensional tectonics was responsible for the opening of the basin and the initial creation of accommodation (1st through 3rd phase). Next, subsidence increased again through transtensional tectonics resulting in the creation of new accommodation (4th-5th phases). Investigations show this double-cycle lake-type evolution is also present in other lake-basins with similar tectonic settings (e.g., both extensional and transtensional tectonics). A different exploration and exploitation strategy should be devoted to the double-cycle evolution of lake basins controlled by extensional to transtensional tectonics in comparison to the single-cycle evolution in extensional or transtensional lake basins.
Liu, Jing; Du, Jianke; Wang, Ji; Yang, Jiashi
2017-03-01
We studied free vibrations of thin-film bulk acoustic wave filters with interdigital electrodes theoretically using the scalar differential equations by Tiersten and Stevens. The filters are made from AlN or ZnO films on Si substrates with ground and driving electrodes. They operate with thickness-extensional modes. The basic vibration characteristics including resonant frequencies and mode shapes were obtained. Their dependence on various geometric parameters was examined. It was found that for properly design filters there exist trapped modes whose vibrations are strong in regions with a driving electrode and decay away from the electrode edges. These trapped modes are essentially long plate thickness-extensional modes modulated by the electrode fingers. The number of trapped modes is sensitive to the geometric parameters.
Prediction of cryogenic cavitation around hydrofoil by an extensional Schnerr-Sauer cavitation model
Sun, T. Z.; Wei, Y. J.; Wang, C.
2015-12-01
Developing a robust computational strategy to address the rich physics characteristic involved in the thermodynamic effects on the cryogenic cavitation remains a challenging problem. The objective of this present study is to model the numerical methodology to simulate the cryogenic cavitation by implanting the thermodynamic effects to the Schnerr-Sauer cavitation model, and coupling the energy equation considered the latent heat. For this purpose, cavitating flows are investigated over a three dimensional hydrofoil in liquid hydrogen and nitrogen. Experimental measurements of pressure and temperature are utilized to validate the extensional Schnerr-Sauer cavitation model. Specifically, the further analysis of the cavitation solution with respect to the thermodynamic term is conducted. The results show that the extensional Schnerr-Sauer cavitation model predicts better accuracy to the quasi-steady cavitation over hydrofoil in the two cryogenic fluids.
Induction of mammalian cell death by simple shear and extensional flows.
Tanzeglock, Timm; Soos, Miroslav; Stephanopoulos, Gregory; Morbidelli, Massimo
2009-10-01
In this work we investigated whether the type of shear flow, to which cells are exposed, influences the initiation of cell death. It is shown that mammalian cells, indeed, distinguish between discrete types of flow and respond differently. Two flow devices were employed to impose accurate hydrodynamic flow fields: uniform steady simple shear flow and oscillating extensional flow. To distinguish between necrotic and apoptotic cell death, fluorescence activated cell sorting and the release of DNA in the culture supernatant was used. Results show that Chinese Hamster Ovaries and Human Embryonic Kidney cells will enter the apoptotic pathway when subjected to low levels of hydrodynamic stress (around 2.0 Pa) in oscillating, extensional flow. In contrast, necrotic death prevails when the cells are exposed to hydrodynamic stresses around 1.0 Pa in simple shear flow or around 500 Pa in extensional flow. These threshold values at which cells enter the respective death pathway should be avoided when culturing cells for recombinant protein production to enhance culture longevity and productivity.
Extensional Tectonic Framework of Post High and Ultrahigh Pressure Metamorphism in Dabieshan, China
1998-01-01
The most prominent feature of the extensional tectonic framework of post high-pressure (HP) and ultrahigh-pressure (UHP) metamorphism in Dabieshan is the development of the multi-layered extension detachment zones surrounding the core of the Luotian dome, and the separation of the UHP, HP and epidote blueschist units by the detachment zones, which form the vertically stacking sheet-like slices of the HP and UHP metamorphic rocks. From the core outwards, exist the HP and UHP rock-barren Dabie complex, UHP unit, HP unit and epidote blueschist unit. The extension tectonics of post HP and UHP metamorphic event constrain the distribution and present configuration of the HP and UHP metamorphic rocks, and the extensional tectonic framework bears some similarities to the Cordillera metamorphic core complex. It is suggested that partial melting happened in the Dabie gneiss complex (DGC) and UHP unit contemporaneously with the extrusion of UHP metamorphic rocks into the lower-middle crust. The formation and emplacement of the migmatite and granites are the response to the change in thermal state, facilitating the transfer from the compressive regime to extensional regime in the crust. The large-scale crustal extension and uplift and the accompanying anatexis in Dabieshan are probably related to the delamination and magmatic underplating in the mantle and the lower crust.
Two-stage partial melting during the Variscan extensional tectonics (Montagne Noire, France)
Poujol, Marc; Pitra, Pavel; Van Den Driessche, Jean; Tartèse, Romain; Ruffet, Gilles; Paquette, Jean-Louis; Poilvet, Jean-Charles
2017-03-01
One of the striking features that characterise the late stages of the Variscan orogeny is the development of gneiss and migmatite domes, as well as extensional Late Carboniferous and Permian sedimentary basins. It remains a matter of debate whether the formation of domes was related to the well-documented late orogenic extension or to the contractional tectonics that preceded. Migmatization and magmatism are expected to predate extension if the domes are compression-related regional anticlines, but they must both precede and be contemporaneous with extension if they are extensional core complexes. In the Montagne Noire area (southern French Massif Central), where migmatization, magmatism and the deformation framework are well documented, the age of the extensional event was unequivocally constrained to 300-290 Ma. Therefore, dating migmatization in this area is a key point for discriminating between the two hypotheses and understanding the Late Palaeozoic evolution of this part of the Variscan belt. For this purpose, a migmatite and an associated anatectic granite from the Montagne Noire dome were dated by LA-ICP-MS (U-Th-Pb on zircon and monazite) and laser probe 40Ar-39Ar (K-Ar on muscovite). Although zircon did not record any Variscan age unequivocally related to compression (380-330 Ma), two age groups were identified from the monazite crystals. A first event, at ca. 319 Ma (U-Th-Pb on monazite), is interpreted as a first stage of migmatization and as the emplacement age of the granite, respectively. A second event at ca. 298-295 Ma, recorded by monazite (U-Th-Pb) and by the muscovite 40Ar-39Ar system in the migmatite and in the granite, could be interpreted as a fluid-induced event, probably related to a second melting event identified through the syn-extensional emplacement of the nearby Montalet leucogranite ca. 295 Ma ago. The ages of these two events post-date the Variscan compression and agree with an overall extensional context for the development of the
Eocene extensional exhumation of basement and arc rocks along southwesternmost Peru, Central Andes.
Noury, Mélanie; Bernet, Matthias; Sempéré, Thierry
2014-05-01
The overthickened crust of the current Central Andes is commonly viewed as the result of tectonic shortening. However, in the present-day terrestrial forearc and arc of southwesternmost Peru, crustal thickness increases from 30 km along the coastline to >60 km below the active arc, whereas the upper crust exhibits little to no evidence of crustal shortening and, in constrast, many extensional features. How (and when) crustal overthickness was acquired in this region is thus little understood. Because crustal overthickening often results in extensional collapse and/or significant erosion, here we address this issue through a regional-scale study of exhumation using fission-track thermochronology. The limited fission-track data previously available in the area suggested that exhumation began during the Mesozoic. In this study, we present new apatite and zircon fission-track data obtained along the current terrestrial forearc of southwesternmost Peru. This relatively restricted area presents the interest of providing extensive outcrops of Precambrian to Ordovician basement and Early Jurassic to Late Cretaceous arc plutons. In order to compare the chronology of exhumation of these units, we performed extensive sampling for fission-track dating, as well as structural mapping. Our results indicate that the basement rocks and Jurassic plutons that crop out in the Arequipa region, where the crust is now >50 km-thick, experienced a rapid cooling through the 240-110°C temperature range between ~65 and ~35 Ma. This period of rapid exhumation coincided in time with the accumulation of terrestrial forearc deposits (the Lower Moquegua Group), that exhibit many syn-sedimentary extensional features and are bounded by conspicuous normal faults, specifically along the region where intense activity of the main arc between ~90 and ~60 Ma had led to voluminous magma emplacement. This close succession of (1) intense magmatic activity and (2) regional-scale exhumation associated with
Maximum Autocorrelation Factorial Kriging
Nielsen, Allan Aasbjerg; Conradsen, Knut; Pedersen, John L.; Steenfelt, Agnete
2000-01-01
This paper describes maximum autocorrelation factor (MAF) analysis, maximum autocorrelation factorial kriging, and its application to irregularly sampled stream sediment geochemical data from South Greenland. Kriged MAF images are compared with kriged images of varimax rotated factors from an ordinary non-spatial factor analysis, and they are interpreted in a geological context. It is demonstrated that MAF analysis contrary to ordinary non-spatial factor analysis gives an objective discrimina...
Maximum-biomass prediction of homofermentative Lactobacillus.
Cui, Shumao; Zhao, Jianxin; Liu, Xiaoming; Chen, Yong Q; Zhang, Hao; Chen, Wei
2016-07-01
Fed-batch and pH-controlled cultures have been widely used for industrial production of probiotics. The aim of this study was to systematically investigate the relationship between the maximum biomass of different homofermentative Lactobacillus and lactate accumulation, and to develop a prediction equation for the maximum biomass concentration in such cultures. The accumulation of the end products and the depletion of nutrients by various strains were evaluated. In addition, the minimum inhibitory concentrations (MICs) of acid anions for various strains at pH 7.0 were examined. The lactate concentration at the point of complete inhibition was not significantly different from the MIC of lactate for all of the strains, although the inhibition mechanism of lactate and acetate on Lactobacillus rhamnosus was different from the other strains which were inhibited by the osmotic pressure caused by acid anions at pH 7.0. When the lactate concentration accumulated to the MIC, the strains stopped growing. The maximum biomass was closely related to the biomass yield per unit of lactate produced (YX/P) and the MIC (C) of lactate for different homofermentative Lactobacillus. Based on the experimental data obtained using different homofermentative Lactobacillus, a prediction equation was established as follows: Xmax - X0 = (0.59 ± 0.02)·YX/P·C.
Martinetti, Luca
At service temperatures, A--B--A thermoplastic elastomers (TPEs) behave similarly to filled (and often entangled) B-rich rubbers since B block ends are anchored on rigid A domains. Therefore, their viscoelastic behavior is largely dictated by chain mobility of the B block rather than by microstructural order. Relating the small- and large-strain response of undiluted A--B--A triblocks to molecular parameters is a prerequisite for designing associated TPE-based systems that can meet the desired linear and nonlinear rheological criteria. This dissertation was aimed at connecting the chemical and topological structure of A--B--A TPEs with their viscoelastic properties, both in the linear and in the nonlinear regime. Since extensional deformations are relevant for the processing and often the end-use applications of thermoplastic elastomers, the behavior was investigated predominantly in uniaxial extension. The unperturbed size of polymer coils is one of the most fundamental properties in polymer physics, affecting both the thermodynamics of macromolecules and their viscoelastic properties. Literature results on poly(D,L-lactide) (PLA) unperturbed chain dimensions, plateau modulus, and critical molar mass for entanglement effect in viscosity were reviewed and discussed in the framework of the coil packing model. Self-consistency between experimental estimates of melt chain dimensions and viscoelastic properties was discussed, and the scaling behaviors predicted by the coil packing model were identified. Contrary to the widespread belief that amorphous polylactide must be intrinsically stiff, the coil packing model and accurate experimental measurements undoubtedly support the flexible nature of PLA. The apparent brittleness of PLA in mechanical testing was attributed to a potentially severe physical aging occurring at room temperature and to the limited extensibility of the PLA tube statistical segment. The linear viscoelastic response of A--B--A TPEs was first
Jaishankar, Aditya; Wee, May; Matia-Merino, Lara; Goh, Kelvin K T; McKinley, Gareth H
2015-06-05
Mamaku gum is a polysaccharide extracted from the fronds of the black tree fern found in New Zealand. The cooked pith has traditionally been used for various medicinal purposes and as a food source by the Maori people of New Zealand. It has potential applications as a thickener in the food industry and as a palliative for patients with dysphagia. Studies on the shear rheology of Mamaku gum have revealed that the gum exhibits shear thickening at a critical shear rate due to a transition from intra- to inter-molecular chain interactions upon shear-induced chain elongation. In this paper, we demonstrate that these interactions are primarily due to hydrogen bonding. We perform extensional rheology on mixtures of Mamaku gum and urea (a known disruptor of hydrogen bonds) to quantify the nature of these interactions. Capillary Breakup Extensional Rheometry (CaBER) performed on the pure Mamaku gum solutions yield plateau values of the Trouton ratio as high as ∼10(4), showing that the viscoelasticity of the gum in uniaxial elongation is much higher than in shear. For all Mamaku concentrations tested, the extensional viscosity decreases upon increasing urea concentration. Furthermore, the relaxation time decreases exponentially with increasing urea concentration. This exponential relationship is independent of the Mamaku concentration, and is identical to the relationships between urea concentration and characteristic timescales measured in nonlinear shear rheology. We show using the sticky reptation model for polymers with multiple sticker groups along the backbone how such a relationship is consistent with a linear decrease in the free energy for hydrogen bond dissociation. We then demonstrate that a time-concentration superposition principle can be used to collapse the viscoelastic properties of the Mamaku-gum/urea mixtures. Copyright © 2015 Elsevier Ltd. All rights reserved.
Origin and role of fluids involved in the seismic cycle of extensional faults in carbonate rocks
Smeraglia, Luca; Berra, Fabrizio; Billi, Andrea; Boschi, Chiara; Carminati, Eugenio; Doglioni, Carlo
2016-09-01
We examine the potentially-seismic right-lateral transtensional-extensional Tre Monti Fault (central Apennines, Italy) with structural and geochemical methods and develop a conceptual evolutionary model of extensional faulting with fluid involvement in shallow (≤3 km depth) faults in carbonate rocks. In the analysed fault zone, multiscale fault rock structures include injection veins, fluidized ultracataclasite layers, and crackle breccias, suggesting that the fault slipped seismically. We reconstructed the relative chronology of these structures through cross-cutting relationship and cathodoluminescence analyses. We then used C- and O-isotope data from different generations of fault-related mineralizations to show a shift from connate (marine-derived) to meteoric fluid circulation during exhumation from 3 to ≤1 km depths and concurrent fluid cooling from ∼68 to hydrological system, where prevalently connate fluids circulated within the fault zone at temperatures between 60° and 75 °C. During fault zone exhumation, at depths ≤1 km and temperatures hydrological circulation became open and meteoric-derived fluids progressively infiltrated and circulated within the fault zone. The role of these fluids during syn-exhumation seismic cycles of the Tre Monti Fault has been substantially passive along the whole fault zone, the fluids being passively redistributed at hydrostatic pressure following co-seismic dilatancy. Only the principal fault has been characterized, locally and transiently, by fluid overpressures. The presence of low-permeability clayey layers in the sedimentary sequence contributed to control the type of fluids infiltrating into the fault zone and possibly their transient overpressures. These results can foster the comprehension of seismic faulting at shallow depths in carbonate rocks of other fold-thrust belts involved in post-collisional seismogenic extensional tectonics.
Extensional and Flexural Waves in a Thin-Walled Graphite/Epoxy Tube
Prosser, William H.; Gorman, Michael R.; Dorighi, John
1992-01-01
Simulated acoustic emission signals were induced in a thin-walled graphite/epoxy tube by means of lead breaks (Hsu-Neilsen source). The tube is of similar material and layup to be used by NASA in fabricating the struts of Space Station Freedom. The resulting waveforms were detected by broad band ultrasonic transducers and digitized. Measurements of the velocities of the extensional and flexural modes were made for propagation directions along the tube axis (0 degrees), around the tube circumference (90 degrees) and at an angle of 45 degrees. These velocities were found to be in agreement with classical plate theory.
Yang Zhongzhu; Chen Shuliang; Li Xiandong; Wang Zhongjiang; Qu Hongxiang; Gang Jiang
2001-01-01
The palaeoproterozoic extensional structure in the east of Liaoning Province underwent sub - bedding ductile shear flowing deformation with metamorphism and magmatic emplacement. The reversal structure following the processes constructed the present framework of palaeoproterozoic orogenic belt. As a result of the ductile shearing along the layers, the gold in the Liaohe group was activated, migrated upward to the interface between the Dashiqiao rock formation, which was lower green schist facies and the Gaixian rock formation, so the gold deposit was formed in the space of brittle - ductile shear zone as ductile - shear - zone - typed stratabound gold deposit.
An Extensional Characterization of Lambda-Lifting and Lambda-Dropping
Danvy, Olivier
1999-01-01
Lambda-lifting and lambda-dropping respectively transform a block-structured functional program into recursive equations and vice versa. Lambda-lifting was developed in the early 80’s, whereas lambda-dropping is more recent. Both are split into an analysis and a transformation. Published work......, however, has only concentrated on the analysis parts. We focus here on the transformation parts and more precisely on their correctness, which appears never to have been proven. To this end, we define extensional versions of lambda-lifting and lambda-dropping and establish their correctness with respect...
An Extensional Characterization of Lambda-Lifting and Lambda-Dropping
Danvy, Olivier
1998-01-01
Lambda-lifting and lambda-dropping respectively transform a block-structured functional program into recursive equations and vice versa. Lambda-lifting was developed in the early 80’s, whereas lambda-dropping is more recent. Both are split into an analysis and a transformation. Published work......, however, has only concentrated on the analysis parts. We focus here on the transformation parts and more precisely on their correctness, which appears never to have been proven. To this end, we define extensional versions of lambda-lifting and lambda-dropping and establish their correctness with respect...
Extensional basin evolution in the presence of small-scale convection
Petersen, Kenni Dinesen; Nielsen, S.B.; Clausen, O.R.
2011-01-01
The plate model of Parsons & Sclater provides a generally accepted, quantitative framework for the thermal subsidence-evolution in extensional basins. It predicts an asymptotic evolution of the geotherm towards a steady state, featuring a constant lithospheric thickness and ceased subsidence...... a two-dimensional, numerical, thermo-mechanical model of the lithosphere and upper mantle to asses the effects of small-scale convection. Given a particular mantle rheology, our model features such convection, and, over time, the horizontally averaged geotherm converges towards a self-consistent, quasi...
Tectono-stratigraphic evolution of an inverted extensional basin: the Cameros Basin (north of Spain)
Omodeo Salè, Silvia; Guimerà, Joan; Mas, Ramón; Arribas, José
2014-09-01
The Cameros Basin is a part of the Mesozoic Iberian Rift. It is an extensional basin formed during the late Jurassic and early Cretaceous, in the Mesozoic Iberian Rift context, and it was inverted in the Cenozoic as a result of the Alpine contraction. This work aims to reconstruct the tectono-stratigraphic evolution of the basin during the Mesozoic, using new and revised field, geophysical and subsurface data. The construction of a basin-wide balanced section with partial restorations herein offers new insights into the geometry of the syn-rift deposits. Field data, seismic lines and oil well data were used to identify the main structures of the basin and the basin-forming mechanisms. Mapping and cross-sectional data indicate the marked thickness variation of the depositional sequences across the basin, suggesting that the extension of the depositional area varied during the syn-rift stage and that the depocentres migrated towards the north. From field observation and seismic line interpretation, an onlap of the depositional sequences to the north, over the marine Jurassic substratum, can be deduced. In the last few decades, the structure and geometry of the basin have been strongly debated. The structure and geometry of the basin infill reconstructed herein strongly support the interpretation of the Cameros Basin as an extensional-ramp synclinal basin formed on a blind south-dipping extensional ramp. The gradual hanging-wall displacement to the south shifted the depocentres to the north over time, thus increasing the basin in size northwards, with onlap geometry on the pre-rift substratum. The basin was inverted by means of a main thrust located in a detachment located in the Upper Triassic beds (Keuper), which branched in depth with the Mesozoic extensional fault flat. The reconstruction of the tectono-stratigraphic evolution of the Cameros Basin proposed herein represents a synthesis and an integration of previous studies of the structure and geometry of the
Dynamics of Star Polymers in Fast Extensional Flow and Stress Relaxation
Huang, Qian; Agostini, Serena; Hengeller, Ludovica
2016-01-01
We confirm the observation from Ianniruberto and Marrucci [ Macromolecules 2013, 46, 267-275 ] that entangled melts of branched polystyrenes behave like linear polystyrenes in the steady state of fast extensional flow, by measuring a linear, an asymmetric star, and a symmetric star polystyrene wi...... they relax in a similar way, most likely via arm retraction, at short time, but behave differently at long time due to both the length of the arm and the branch point. The terminal relaxation is described by a Doi and Edwards based model, i.e., considering pure orientational relaxation....
Maximum likely scale estimation
Loog, Marco; Pedersen, Kim Steenstrup; Markussen, Bo
2005-01-01
A maximum likelihood local scale estimation principle is presented. An actual implementation of the estimation principle uses second order moments of multiple measurements at a fixed location in the image. These measurements consist of Gaussian derivatives possibly taken at several scales and/or ...
Varga, Robert J.; Faulds, James E.; Snee, Lawrence W.; Harlan, Stephen S.; Bettison-Varga, Lori
2004-02-01
Recent studies demonstrate that rifts are characterized by linked tilt domains, each containing a consistent polarity of normal faults and stratal tilt directions, and that the transition between domains is typically through formation of accommodation zones and generally not through production of throughgoing transfer faults. The mid-Miocene Black Mountains accommodation zone of southern Nevada and western Arizona is a well-exposed example of an accommodation zone linking two regionally extensive and opposing tilt domains. In the southeastern part of this zone near Kingman, Arizona, east dipping normal faults of the Whipple tilt domain and west dipping normal faults of the Lake Mead domain coalesce across a relatively narrow region characterized by a series of linked, extensional folds. The geometry of these folds in this strike-parallel portion of the accommodation zone is dictated by the geometry of the interdigitating normal faults of opposed polarity. Synclines formed where normal faults of opposite polarity face away from each other whereas anticlines formed where the opposed normal faults face each other. Opposed normal faults with small overlaps produced short folds with axial trends at significant angles to regional strike directions, whereas large fault overlaps produce elongate folds parallel to faults. Analysis of faults shows that the folds are purely extensional and result from east/northeast stretching and fault-related tilting. The structural geometry of this portion of the accommodation zone mirrors that of the Black Mountains accommodation zone more regionally, with both transverse and strike-parallel antithetic segments. Normal faults of both tilt domains lose displacement and terminate within the accommodation zone northwest of Kingman, Arizona. However, isotopic dating of growth sequences and crosscutting relationships show that the initiation of the two fault systems in this area was not entirely synchronous and that west dipping faults of the
Maximum information photoelectron metrology
Hockett, P; Wollenhaupt, M; Baumert, T
2015-01-01
Photoelectron interferograms, manifested in photoelectron angular distributions (PADs), are a high-information, coherent observable. In order to obtain the maximum information from angle-resolved photoionization experiments it is desirable to record the full, 3D, photoelectron momentum distribution. Here we apply tomographic reconstruction techniques to obtain such 3D distributions from multiphoton ionization of potassium atoms, and fully analyse the energy and angular content of the 3D data. The PADs obtained as a function of energy indicate good agreement with previous 2D data and detailed analysis [Hockett et. al., Phys. Rev. Lett. 112, 223001 (2014)] over the main spectral features, but also indicate unexpected symmetry-breaking in certain regions of momentum space, thus revealing additional continuum interferences which cannot otherwise be observed. These observations reflect the presence of additional ionization pathways and, most generally, illustrate the power of maximum information measurements of th...
Rasmussen, Henrik Koblitz; Bach, Anders; Bastian, Heike
2002-01-01
In many polymer processing operations, the polymer molecules becomes highly elongated and the extensional viscosity becomes an inportant parameter in estimating properties during and after the process....
Rasmussen, Henrik Koblitz; Bach, Anders; Bastian, Heike
2002-01-01
In many polymer processing operations, the polymer molecules becomes highly elongated and the extensional viscosity becomes an inportant parameter in estimating properties during and after the process....
Gunes, Deniz Z; Clain, Xavier; Breton, Olivier; Mayor, Guy; Burbidge, Adam S
2010-03-01
From two-drop collision experiments, it is known that local extensional flow favors coalescence. Recently, Bremond et al. used microfluidic methods to evidence this point. Similarly, we used specific microfluidic geometries to impose sudden extensional flow, following drop collision under controlled conditions, and coalescence events were recorded with a high-speed camera. In this study we focus on the effect of surfactant on the coalescence, or stabilisation against it, between drops flowing apart due to either imposed external flow or capillary forces related to drop shape relaxation. Coalescence can be induced even when drops are initially separated by an intersticial lubricating film by far thicker than the critical thickness for rupturing under the action of Van der Waals forces. This is particularly relevant to avalanches of coalescence events, in flowing or even quiescent emulsions or foams. When non-ionic surfactant was used, it was observed that small concentrations apparently enhance coalescence in extension. But at higher concentrations it provides stabilisation through a specific mechanism of thread formation and rupture; the stabilisation mechanism can be complex.
Mulligan, Molly K; Rothstein, Jonathan P
2011-08-16
Using a microfluidic flow-focusing device, monodisperse water droplets in oil were generated and their interface populated by either 1 μm or 500 nm amine modified silica particles suspended in the water phase. The deformation and breakup of these Pickering droplets were studied in both pure extensional flow and combined extensional and shear flow at various capillary numbers using a microfluidic hyperbolic contraction. The shear resulted from droplet confinement and increased with droplet size and position along the hyperbolic contraction. Droplet deformation was found to increase with increasing confinement and capillary number. At low confinements and low capillary numbers, the droplet deformation followed the predictions of theory. For fully confined droplets, where the interface was populated by 1 μm silica particles, the droplet deformation increased precipitously and two tails were observed to form at the rear of the droplet. These tails were similar to those seen for surfactant covered droplets. At a critical capillary number, daughter droplets were observed to stream from these tails. Due to the elasticity of the particle-laden interface, these drops did not return to a spherical shape, but were observed to buckle. Although increases in droplet deformation were observed, no tail streaming occurred for the 500 nm silica particle covered droplets over the range of capillary numbers studied.
Hashemi, Seyed M.; Roach, Andrew
2011-12-01
The application of a Dynamic Finite Element (DFE) technique to the extensional-torsional free vibration analysis of nonuniform composite beams, in the absence of flexural coupling, is presented. The proposed method is a fusion of the Galerkin weighted residual formulation and the Dynamic Stiffness Matrix (DSM) method, where the basis functions of approximation space are assumed to be the closed form solutions of the differential equations governing uncoupled extensional and torsional vibrations of the beam. The use of resulting dynamic trigonometric interpolation (shape) functions leads to a frequency dependent stiffness matrix, representing both mass and stiffness properties of the beam element. Assembly of the element matrices and the application of the boundary conditions then leads to a frequency dependent nonlinear eigenproblem, which is solved to evaluate the system natural frequencies and modes. Two illustrative examples of uniform and tapered cantilevered, Circumferentially Uniform Stiffness ( CUS), hollow, composite beams are presented. The influence of ply fibre-angle on the natural frequencies is also studied. The correctness of the theory and the superiority of the proposed DFE over the contrasting DSM and conventional FEM methods are confirmed by the published results and numerical checks. The discussion of results is followed by some concluding remarks.
Reflection of drill-string extensional waves at the bit-rock contact.
Poletto, Flavio; Malusa, Massimo
2002-06-01
Downward propagating extensional waves are partially reflected at the bit-rock contact. The evaluation of the reflection coefficient is important to obtain while drilling information about the acoustic properties of the formations. The scope of this work is to estimate the bit-rock reflection coefficient, assuming a flat drill bit in perfect contact with the formation. Using the low-frequency approximation, which holds when the wavelength is much larger than the lateral dimensions of the borehole, the drill-string is assumed to be a laterally free rod, and the formation an homogeneous and isotropic medium. This work shows that the reflection coefficient of the extensional waves depends, along with the elastic properties of the formation, on the ratio of the cross sections of the drill-string and borehole. The impedance of the drilled rock can be calculated from the measured reflection coefficient, which is related to the amplitude of waves produced in the string and in the formation by a working drill-bit.
Minor, S. A.; Caine, J. S.; Fridrich, C.; Hudson, M. R.
2015-12-01
Our understanding of extensional strain transfer and accommodation in continental rifts has grown considerably, but few studied transfer zones exhibit high internal topographic and structural relief. In the Rio Grande rift of Colorado the WNW-trending northern tip of the Sangre de Cristo Range separates the opposite-tilted Upper Arkansas River (UAR) and San Luis half grabens. We have investigated the development and role of faults flanking this "Poncha" intrarift mountain block in transferring extension between rift basins, mountain block surface uplift, and landscape evolution. The topographically rugged Poncha block consists of Proterozoic metamorphic and plutonic rocks overlain on its west and southwest flanks by 34.5-33-Ma volcanic rocks and alluvial deposits of the Mio-Pliocene Dry Union Formation. Similar Dry Union sediments underlie a moderately elevated, strongly dissected older piedmont along the northern front of the mountain block. All of these units are tilted 10-35º to the W and SW. A WNW-trending, right-stepping fault system > 25 km in length separates the piedmont and UAR basin from the steep northern Poncha mountain front. Slip measurements along this fault system, cutting deposits as young as ~200 ka, indicate dextral-normal oblique movement. The NNW-striking, down-to-E southern Sawatch range-front fault system forms the western terminus of the Poncha block where it juxtaposes Dry Union deposits against Sawatch Proterozoic basement rocks. Gently tilted proximal diamicton and alluvial deposits on the downthrown blocks of both range-front faults likely mark Plio-Pleistocene(?) mountain block uplift. Arrays of NNW- to WNW-striking faults cutting volcanic and Dry Union units on the flanks of the Poncha block commonly have normal-oblique slip, with greater tendency for dextral strike-slip components on WNW-striking faults. Preliminary paleomagnetic data from the volcanic rocks detect no significant vertical-axis rotation that accompanied oblique
Maximum Likelihood Associative Memories
Gripon, Vincent; Rabbat, Michael
2013-01-01
Associative memories are structures that store data in such a way that it can later be retrieved given only a part of its content -- a sort-of error/erasure-resilience property. They are used in applications ranging from caches and memory management in CPUs to database engines. In this work we study associative memories built on the maximum likelihood principle. We derive minimum residual error rates when the data stored comes from a uniform binary source. Second, we determine the minimum amo...
Maximum likely scale estimation
Loog, Marco; Pedersen, Kim Steenstrup; Markussen, Bo
2005-01-01
A maximum likelihood local scale estimation principle is presented. An actual implementation of the estimation principle uses second order moments of multiple measurements at a fixed location in the image. These measurements consist of Gaussian derivatives possibly taken at several scales and....../or having different derivative orders. Although the principle is applicable to a wide variety of image models, the main focus here is on the Brownian model and its use for scale selection in natural images. Furthermore, in the examples provided, the simplifying assumption is made that the behavior...... of the measurements is completely characterized by all moments up to second order....
Croci, Andrea; Della Porta, Giovanna; Capezzuoli, Enrico
2016-03-01
The extensional Neogene Albegna Basin (Southern Tuscany, Italy) includes several thermogene travertine units dating from the Miocene to Holocene time. During the late Miocene (Messinian), a continental fault-controlled basin (of nearly 500-km2 width) was filled by precipitated travertine and detrital terrigenous strata, characterized by a wedge-shaped geometry that thinned northward, with a maximum thickness of nearly 70 m. This mixed travertine-terrigenous succession was investigated in terms of lithofacies types, depositional environment and architecture and the variety of precipitated travertine fabrics. Deposited as beds with thickness ranging from centimetres to a few decimetres, carbonates include nine travertine facies types: F1) clotted peloidal micrite and microsparite boundstone, F2) raft rudstone/floatstone, F3) sub-rounded radial coated grain grainstone, F4) coated gas bubble boundstone, F5) crystalline dendrite cementstone, F6) laminated boundstone, F7) coated reed boundstone and rudstone, F8) peloidal skeletal grainstone and F9) calci-mudstone and microsparstone. Beds of terrigenous deposits with thickness varying from a decimetre to > 10 m include five lithofacies: F10) breccia, F11) conglomerate, F12) massive sandstone, F13) laminated sandstone and F14) claystone. The succession recorded the following three phases of evolution of the depositional setting: 1) At the base, a northward-thinning thermogene travertine terraced slope (Phase I, travertine slope lithofacies association, F1-F6) developed close to the extensional fault system, placed southward with respect to the travertine deposition. 2) In Phase II, the accumulation of travertines was interrupted by the deposition of colluvial fan deposits with a thickness of several metres (colluvial fan lithofacies association, F10 and F12), which consisted of massive breccias, adjacent to the alluvial plain lithofacies association (F11-F14) including massive claystone and sandstone and channelized
F. TopsÃƒÂ¸e
2001-09-01
Full Text Available Abstract: In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over
Regularized maximum correntropy machine
Wang, Jim Jing-Yan
2015-02-12
In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.
Extensional flow of nematic liquid crystal with an applied electric field
CUMMINGS, L. J.
2013-10-17
Systematic asymptotic methods are used to formulate a model for the extensional flow of a thin sheet of nematic liquid crystal. With no external body forces applied, the model is found to be equivalent to the so-called Trouton model for Newtonian sheets (and fibres), albeit with a modified \\'Trouton ratio\\'. However, with a symmetry-breaking electric field gradient applied, behaviour deviates from the Newtonian case, and the sheet can undergo finite-time breakup if a suitable destabilizing field is applied. Some simple exact solutions are presented to illustrate the results in certain idealized limits, as well as sample numerical results to the full model equations. Copyright © Cambridge University Press 2013.
Cagliani, Alberto; Kosaka, Priscila; Tamayo, Javier; Davis, Zachary James
2012-05-08
We have fabricated an ultrasensitive nanomechanical resonator based on the extensional vibration mode to weigh the adsorbed water on self-assembled monolayers of DNA as a function of the relative humidity. The water adsorption isotherms provide the number of adsorbed water molecules per nucleotide for monolayers of single stranded (ss) DNA and after hybridization with the complementary DNA strand. Our results differ from previous data obtained with bulk samples, showing the genuine behavior of these self-assembled monolayers. The hybridization cannot be inferred from the water adsorption isotherms due to the low hybridization efficiency of these highly packed monolayers. Strikingly, we efficiently detect the hybridization by measuring the thermal desorption of water at constant relativity humidity. This finding adds a new nanomechanical tool for developing a label-free nucleic acid sensor based on the interaction between water and self-assembled monolayers of nucleic acids.
Genetic model of hanging wall syncline and central dome in extensional fault
刘德来; 丁贵明; 鲁兵
2002-01-01
Hanging wall syncline and central dome are special extension structures, developing over the hanging wall in an extensional ramp-flat fault. Under the condition that the flat is sub-horizontal, the hanging wall syncline is separated from the half graben by the central dome. And on the dome forms an erosional surface. Both sediments in the half graben and erosional surface on the top of the central dome extended over the dome and entered into the hanging wall syncline with extension going on. Meanwhile, those having entered were overlapped by new sedimentary layers in the hanging wall syncline, so that there is a together-threaded, diachronic unconformity to form in the same epoch stratum. The layers in the hanging wall syncline also have an attribute of migrating laterally and getting tilted with extension. There is no sedimentation on the central dome. But sediments, which came from the half graben, got thicker over the dome in extension.
Tavani, Stefano; Carola, Eloi; Granado, Pablo; Quintã, Anna; MuñOz, Josep Anton
2013-03-01
In the Basque-Cantabrian Basin (Spain), normal faulting and associated folding occurred during Late Jurassic to Early Cretaceous rifting. Cenozoic Pyrenean thick-skinned transpressive inversion in the western parts of the basin preserved the first-order extensional architecture. Integration of geological maps and seismic profiles has permitted to fully constrain the style of extensional deformation and subsequent inversion in the western portion of the Basque-Cantabrian Basin. Extensional faults offset the Paleozoic basement up to Lower Triassic rocks. The presence of an efficient décollement level represented by Triassic evaporites produced the decoupling between basement rocks and the Upper Triassic to Middle Jurassic prerift cover sequence. Extensional forced folding occurred in the cover, driven by basement faulting and the migration of evaporites toward the hanging wall of the extensional faults, with salt welds developing away from them. Upper Jurassic to Lower Cretaceous syn-rift sediments deposited synchronously with forced folding, which led to the development of extensional growth geometries associated with both master faults and nearly-transverse faults. Syn-rift growth sequences are characterized by downlap and onlap relationships with the underlying prerift units, interpreted as the result of along-strike variations of master fault extensional displacement rate. Cenozoic Pyrenean contraction generated the right-lateral transpressive inversion of basement master faults and the almost dip-slip reactivation of transverse extensional faults.
Okay, Aral I.; Altiner, Demir
2016-10-01
The Haymana region in Central Anatolia is located in the southern part of the Pontides close to the İzmir-Ankara suture. During the Cretaceous, the region formed part of the south-facing active margin of the Eurasia. The area preserves a nearly complete record of the Cretaceous system. Shallow marine carbonates of earliest Cretaceous age are overlain by a 700-m-thick Cretaceous sequence, dominated by deep marine limestones. Three unconformity-bounded pelagic carbonate sequences of Berriasian, Albian-Cenomanian and Turonian-Santonian ages are recognized: Each depositional sequence is preceded by a period of tilting and submarine erosion during the Berriasian, early Albian and late Cenomanian, which corresponds to phases of local extension in the active continental margin. Carbonate breccias mark the base of the sequences and each carbonate sequence steps down on older units. The deep marine carbonate deposition ended in the late Santonian followed by tilting, erosion and folding during the Campanian. Deposition of thick siliciclastic turbidites started in the late Campanian and continued into the Tertiary. Unlike most forearc basins, the Haymana region was a site of deep marine carbonate deposition until the Campanian. This was because the Pontide arc was extensional and the volcanic detritus was trapped in the intra-arc basins and did not reach the forearc or the trench. The extensional nature of the arc is also shown by the opening of the Black Sea as a backarc basin in the Turonian-Santonian. The carbonate sedimentation in an active margin is characterized by synsedimentary vertical displacements, which results in submarine erosion, carbonate breccias and in the lateral discontinuity of the sequences, and differs from blanket like carbonate deposition in the passive margins.
Extensional Seismogenic Stress and Tectonic Movement on the Central Region of the Tibetan Plateau
Jiren Xu
2009-01-01
Full Text Available Various earthquake fault types, mechanism solutions and stress fields, as well as GPS and geothermal data are analyzed for the study of the crustal movements on the Tibetan plateau and their tectonic implications. The results show that a lot of the normal faulting type-event concentrated at altitudes greater than 4000 m on the central Tibetan plateau. The altitudes concentrating normal faulting type-events can be zoned two parts: the western part, the Lhasa block, and the eastern part, the Qiangtang-Changdu region. The azimuths of T-axes are in a general E-W direction in the Lhasa block and NW-SE or NNW-SSE in the Qiangtang-Changdu region at the altitudes of the Tibetan plateau. The tensional stresses in E-W direction and NW-SE direction predominate normal faulting earthquake occurrence in the Lhasa block and the Qiangtang-Changdu region, respectively. The slipping displacements of the normal-faulting-type events have great components in near E-W direction and NW-SE direction in the Lhasa block and the Qiangtang-Changdu region, respectively. The extensions are probably an eastward or southeastward extensional motion, being mainly tectonic activity phenomena in the plateau altitudes. The extensional motions due to normal-fault earthquakes are important tectonic activity regimes on the high altitudes of the plateau. The easterly crustal extensions on the plateau are attributable to the gravitational collapse of the high plateau and eastward extrusion of hotter mantle materials beneath the eastern boundary of the plateau. Numbers of thrust-fault and strike-slip-fault earthquakes with strong compressive stress in a general NNE-SSW direction occur on the edges of the plateau.
蒋海昆; 马胜利; 张流; 侯海峰; 曹文海
2002-01-01
The spatio-temporal characteristics of acoustic emission (AE) during the deformation of rock samples with compressional and extensional en-echelon faults have been studied. The results show that the pre-existing structure can significantly influence the patterns of AE spatial distribution. With increasing of differential stress, AE events firstly cluster around the two ends of pre-existing faults inside the jog and then along the line joining the two ends. The biggish AE events often occur around one end repeatedly. The image of AE clusters indicates the direction and the area of the fracture propagation. The direction of the macroscopic fracture in extensional and compressional jogs is perpendicular and parallel to the direction of axial stress, respectively. The weakening process before the fracturing of jog area is remarkable, and one of the typical precursors for the instability is that the cumulative frequency of AE events increases exponentially. After the fracturing of the jog the frequency and releasing strain energy of AE events decrease gradually. During the friction period, there is no precursory increasing of AE activity before the big stick-slip events. The change of b value in jog shows a typical change of "decreasing tendentiously →returning quickly" before the instability. The decrease of b value occurs in the process of stress increasing and sometime goes down to the weakening stage, and the quick increase b values appears in a short time just before the instability. The comparative analysis shows that the difference in b value due to the different structures is larger than b value variation caused by increase of the differential stress. For the same sample, the temporal sequence of AE is strongly affected by the mechanical state, and the high loading velocity corresponds to the high release rate of strain energy and low b value. Due to its lower failure strength, the broken area is sensitive to small changes in differential stress. Therefore, it
Smart, Kevin J.; Wyrick, Danielle Y.; Ferrill, David A.
2011-04-01
Pit craters, circular to elliptical depressions that lack a raised rim or ejecta deposits, are common on the surface of Mars. Similar structures are also found on Earth, Venus, the Moon, and smaller planetary bodies, including some asteroids. While it is generally accepted that these pits form in response to material drainage into a subsurface void space, the primary mechanism(s) responsible for creating the void is a subject of debate. Previously proposed mechanisms include collapse into lave tubes, dike injection, extensional fracturing, and dilational normal faulting. In this study, we employ two-dimensional discrete element models to assess both extensional fracturing and dilational normal faulting as mechanisms for forming pit craters. We also examine the effect of mechanical stratigraphy (alternating strong and weak layers) and variation in regolith thickness on pit morphology. Our simulations indicate that both extensional fracturing and dilational normal faulting are viable mechanisms. Both mechanisms lead to generally convex (steepening downward) slope profiles; extensional fracturing results in generally symmetric pits, whereas dilational normal faulting produces strongly asymmetric geometries. Pit width is established early, whereas pit depth increases later in the deformation history. Inclusion of mechanical stratigraphy results in wider and deeper pits, particularly for the dilational normal faulting, and the presence of strong near-surface layers leads to pits with distinct edges as observed on Mars. The modeling results suggest that a thicker regolith leads to wider but shallower pits that are less distinct and may be more difficult to detect in areas of thick regolith.
Equalized near maximum likelihood detector
2012-01-01
This paper presents new detector that is used to mitigate intersymbol interference introduced by bandlimited channels. This detector is named equalized near maximum likelihood detector which combines nonlinear equalizer and near maximum likelihood detector. Simulation results show that the performance of equalized near maximum likelihood detector is better than the performance of nonlinear equalizer but worse than near maximum likelihood detector.
Cheeseman, Peter; Stutz, John
2005-01-01
A long standing mystery in using Maximum Entropy (MaxEnt) is how to deal with constraints whose values are uncertain. This situation arises when constraint values are estimated from data, because of finite sample sizes. One approach to this problem, advocated by E.T. Jaynes [1], is to ignore this uncertainty, and treat the empirically observed values as exact. We refer to this as the classic MaxEnt approach. Classic MaxEnt gives point probabilities (subject to the given constraints), rather than probability densities. We develop an alternative approach that assumes that the uncertain constraint values are represented by a probability density {e.g: a Gaussian), and this uncertainty yields a MaxEnt posterior probability density. That is, the classic MaxEnt point probabilities are regarded as a multidimensional function of the given constraint values, and uncertainty on these values is transmitted through the MaxEnt function to give uncertainty over the MaXEnt probabilities. We illustrate this approach by explicitly calculating the generalized MaxEnt density for a simple but common case, then show how this can be extended numerically to the general case. This paper expands the generalized MaxEnt concept introduced in a previous paper [3].
Cortinovis, Silvia; Balsamo, Fabrizio; Storti, Fabrizio
2017-04-01
The study of the microstructural and petrophysical evolution of cataclasites and gouges has a fundamental impact on both hydraulic and frictional properties of fault zones. In the last decades, growing attention has been payed to the characterization of carbonate fault core rocks due to the nucleation and propagation of coseismic ruptures in carbonate successions (e.g., Umbria-Marche 1997, L'Aquila 2009, Amatrice 2016 earthquakes in Central Apennines, Italy). Among several physical parameters, grain size and shape in fault core rocks are expected to control the way of sliding along the slip surfaces in active fault zones, thus influencing the propagation of coseismic ruptures during earthquakes. Nevertheless, the role of grain size and shape distribution evolution in controlling the weakening or strengthening behavior in seismogenic fault zones is still not fully understood also because a comprehensive database from natural fault cores is still missing. In this contribution, we present a preliminary study of seismogenic extensional fault zones in Central Apennines by combining detailed filed mapping with grain size and microstructural analysis of fault core rocks. Field mapping was aimed to describe the structural architecture of fault systems and the along-strike fault rock distribution and fracturing variations. In the laboratory we used a Malvern Mastersizer 3000 granulometer to obtain a precise grain size characterization of loose fault rocks combined with sieving for coarser size classes. In addition, we employed image analysis on thin sections to quantify the grain shape and size in cemented fault core rocks. The studied fault zones consist of an up to 5-10 m-thick fault core where most of slip is accommodated, surrounded by a tens-of-meters wide fractured damage zone. Fault core rocks consist of (1) loose to partially cemented breccias characterized by different grain size (from several cm up to mm) and variable grain shape (from very angular to sub
Droplet Deformation in an Extensional Flow: The Role of Surfactant Physical Chemistry
Stebe, Kathleen J.
1996-01-01
Surfactant-induced Marangoni effects strongly alter the stresses exerted along fluid particle interfaces. In low gravity processes, these stresses can dictate the system behavior. The dependence of Marangoni effects on surfactant physical chemistry is not understood, severely impacting our ability to predict and control fluid particle flows. A droplet in an extensional flow allows the controlled study of stretching and deforming interfaces. The deformations of the drop allow both Marangoni stresses, which resist tangential shear, and Marangoni elasticities, which resist surface dilatation, to develop. This flow presents an ideal model system for studying these effects. Prior surfactant-related work in this flow considered a linear dependence of the surface tension on the surface concentration, valid only at dilute surface concentrations, or a non-linear framework at concentrations sufficiently dilute that the linear approximation was valid. The linear framework becomes inadequate for several reasons. The finite dimensions of surfactant molecules must be taken into account with a model that includes surfaces saturation. Nonideal interactions between adsorbed surfactant molecules alter the partitioning of surfactant between the bulk and the interface, the dynamics of surfactant adsorptive/desorptive exchange, and the sensitivity of the surface tension to adsorbed surfactant. For example, cohesion between hydrocarbon chains favors strong adsorption. Cohesion also slows the rate of desorption from interfaces, and decreases the sensitivity of the surface tension to adsorbed surfactant. Strong cohesive interactions result in first order surface phase changes with a plateau in the surface tension vs surface concentration. Within this surface concentration range, the surface tension is decoupled from surface concentration gradients. We are engaged in the study of the role of surfactant physical chemistry in determining the Marangoni stresses on a drop in an extensional
Extensional crustal tectonics and crust-mantle coupling, a view from the geological record
Jolivet, Laurent; Menant, Armel; Clerc, Camille; Sternai, Pietro; Ringenbach, Jean-Claude; Bellahsen, Nicolas; Leroy, Sylvie; Faccenna, Claudio; Gorini, Christian
2017-04-01
In passive margins or back-arc regions, extensional deformation is often asymmetric, i.e. normal faults or extensional ductile shear zones dip in the same direction over large distances. We examine a number of geological examples in convergent or divergent contexts suggesting that this asymmetry results from a coupling between asthenospheric flow and crustal deformation. This is the case of the Mediterranean back-arc basins, such as the Aegean Sea, the northern Tyrrhenian Sea, the Alboran domain or the Gulf of Lion passive margin. Similar types of observation can be made on some of the Atlantic volcanic passive margins and the Afar region, which were all formed above a mantle plume. We discuss these contexts and search for the main controlling parameters for this asymmetric distributed deformation that imply a simple shear component at the scale of the lithosphere. The different geodynamic settings and tectonic histories of these different examples provide natural case-studies of the different controlling parameters, including a pre-existing heterogeneity of the crust and lithosphere (tectonic heritage) and the possible contribution of the underlying asthenospheric flow through basal drag or basal push. We show that mantle flow can induce deformation in the overlying crust in case of high heat flow and thin lithosphere. In back-arc regions, the cause of asymmetry resides in the relative motion between the asthenosphere below the overriding plate and the crust. When convergence and slab retreat work concurrently the asthenosphere flows faster than the crust toward the trench and the sense of shear is toward the upper plate. When slab retreat is the only cause of subduction, the sense of shear is opposite. In both cases, mantle flow is mostly the consequence of slab retreat and convergence. Mantle flow can however result also from larger-scale convection, controlling rifting dynamics prior to the formation of oceanic crust. In volcanic passive margins, in most cases
付强
2008-01-01
The shearing extension is a main factor in the extrusion process of LC polymer melt. Using the constitutive equation of LCP-B for LC polymer melts and solutions, the influence of orientational motion on extensional viscosity is studied. The change curves of dimensionless extensional viscosity with relaxation time and shear rate have been obtained.%在液晶高分子熔液挤出过程中,剪切拉伸是主要考虑因素.用液晶高分子B模型本构方程,并考虑取向运动的影响得到拉伸粘度随松驰时间与拉伸率之间的变化关系和曲线.
Buckling of thin viscous sheets with inhomogenous viscosity under extensional flows
Srinivasan, Siddarth; Wei, Zhiyan; Mahadevan, L.
2016-11-01
We investigate the dynamics, shape and stability of a thin viscous sheet subjected to an extensional flow under an imposed non-uniform temperature field. Using finite element simulations, we first solve for the stretching flow to determine the pre-buckling sheet thickness and in-plane flow velocities. Next, we use this solution as the base state and solve the linearized partial differential equation governing the out-of-plane deformation of the mid-surface as a function of two dimensionless operating parameters: the normalized stretching ratio α and a dimensionless width of the heating zone β. We show the sheet can become unstable via a buckling instability driven by the development of localized compressive stresses, and determine the global shape and growth rates of the most unstable mode. The growth rate is shown to exhibit a transition from stationary to oscillatory modes in region upstream of the heating zone. Finally, we investigate the effect of surface tension and present an operating diagram that indicates regions of the parameter space that minimizes or entirely suppresses the instability while achieving desired outlet sheet thickness. Therefore, our work is directly relevant to various industrial processes including the glass redraw & float-glass method.
Dong, Hao; Wei, Wenbo; Jin, Sheng; Ye, Gaofeng; Zhang, Letian; Jing, Jian'en; Yin, Yaotian; Xie, Chengliang; Jones, Alan G.
2016-11-01
Despite extensive effort over many decades to understand the tectonic evolution of the Tibetan Plateau, the geodynamic processes creating the iconic south-eastward expansion of the plateau at the Eastern Himalayan Syntaxis (EHS) are still unclear and are hotly debated. Two popular (but not necessarily exclusive) geodynamic models, namely crustal flow at mid-to-lower crustal depths and coherent deformation between the crust and lithospheric mantle, are commonly invoked to explain the expansion mechanism. However, neither of these is able to reconcile all of the abundant geological and geophysical data. Here we present a three-dimensional (3D) geo-electrical model, derived from new SINOPROBE magnetotelluric (MT) array data, that reveals the geo-electrical, and by inference rheological, structure of southeast Tibet. Instead of NW-SE conductive channels proposed in prior two-dimensional (2D) MT studies, distinct NNE-SSW directed quasi-linear conductive anomalies are identified in the mid-to-lower crust, which are separated by a large-scale electrically resistive structure that extends from the crust to the upper mantle. This argues against the prior proposed model of south-eastward conductive anomalies, and hence against the southeast lower crust flow of material. To interpret our observations and resultant model, a new mechanism of "extensional extrusion" is proposed to address the lithospheric deformation of the south-eastward expansion of Tibetan Plateau.
A constitutive analysis of the extensional flows of nearly monodisperse polyisoprene melts
Rasmussen, Henrik K.
2016-01-01
Here two particular formulations [M.H. Wagner, S. Kheirandish, O. Hassager, Journal of Rheology 49 (6) (2005) 1317–1327; H.K. Rasmussen, Q. Huang, Rheologica Acta 53 (3) (2014) 199–208; G. Marrucci, G. Ianniruberto, Macromolecules 37 (10) (2004) 3934–3942] of the ‘interchain pressure’ [39......], incorporated into the molecular stress function method [M.H. Wagner, S. Kheirandish, O. Hassager, Journal of Rheology 49 (6) (2005) 1317–1327], are used to assess the extensional [J.K. Nielsen, O. Hassager, H.K Rasmussen, G.H. McKinley, Journal of Rheology 53 (6) (2009) 1327–1346; G. Liu, H. Sun, S. Rangou, K....... Ntetsikas, A. Avgeropoulos, S.-Q. Wang, Journal of Rheology 57 (1) (2013) 89–104] and shear viscosities [D. Auhl, J. Ramirez, A.E. Likhtman, P. Chambon, C. Fernyhough, Journal of Rheology 52 (3) (2008) 801–835] of narrow molecular weight distributed (NMMD) polyisoprene melts. These two formulations...
Constraints for timing of extensional tectonics in the western margin of the Red Sea in Eritrea
Ghebreab, Woldai; Carter, Andrew; Hurford, Anthony J.; Talbot, Christopher J.
2002-06-01
Recent work on asthenosphere-lithosphere coupling reinforces past observations that active and passive rifting models do not adequately describe real rifts. There remains insufficient knowledge of fundamental controls on rift architecture. In the actively extending Red Sea margin of eastern Eritrea, which lies at the Red Sea/Danakil-Gulf of Aden and the East African rift triple junction zone, the geometry and kinematics of extension are complex and poorly defined due to large data gaps. Extension and sea-floor spreading in both the Red Sea and Gulf of Aden have influenced the Neogene tectonic development of Eritrea but many of the structures have Pan-African origins and do not follow normal plate opening geometries. To constrain the rifting history in eastern Eritrea, apatite fission-track thermochronologic data were measured for 22 Pan-African rock samples. Results identify late Oligocene-early Miocene cooling coincident with extension and erosion along the conjugate margin in Yemen. A younger age group, confined to Mt Ghedem, relates to an episode of fault reactivation and dyke injection that began ˜10 Ma coincident with rotation of the nearby Danakil block. Initially this was driven by onset of sea-floor spreading in the Gulf of Aden and later, in the Pliocene, aided by northward rifting in the Afar depression concomitant with spreading in the Red Sea. These different processes highlight the complex linkage between different extensional events and rift architecture.
Subrahmanyam, K. B.; Kaza, K. R. V.
1985-01-01
The effects of pretwist, precone, setting angle, Coriolis forces and second degree geometric nonlinearities on the natural frequencies, steady state deflections and mode shapes of rotating, torsionally rigid, cantilevered beams were studied. The governing coupled equations of flap lag extensional motion are derived including the effects of large precone and retaining geometric nonlinearities up to second degree. The Galerkin method, with nonrotating normal modes, is used for the solution of both steady state nonlinear equations and linear perturbation equations. Parametric indicating the individual and collective effects of pretwist, precone, Coriolis forces and second degree geometric nonlinearities on the steady state deflection, natural frequencies and mode shapes of rotating blades are presented. It is indicated that the second degree geometric nonlinear terms, which vanish for zero precone, can produce frequency changes of engineering significance. Further confirmation of the validity of including those generated by MSC NASTRAN. It is indicated that the linear and nonlinear Coriolis effects must be included in analyzing thick blades. The Coriolis effects are significant on the first flatwise and the first edgewise modes.
A New Accumulation Model of Coal Seams in France Extensional Basins
无
2000-01-01
This paper, based on the sedimentary features of the coal seams in the typical extensional (faulted) coal basins between two inland mountainous areas of the Central Massif (France) deals with the accumulation mechanism and the corresponding sedimentary-tectonic conditions of these thick coalbeds, and proposes a new coal accumulation model for the inland lacustrine-basin thick coalbeds. The presence of a great number of gravity-flow sediments such as detrital flow, diluted slurry flow or turbidity-current sediments in the coal seams, and that of the contemporaneous gravity slump and deformation structure in the coal seam itself bath indicate that thelacustrine environment in the accumulation of the thick coalbeds was characterized by the relatively deep flood and violent sedimentation. This model can not only interpret reasonably the accumulation mecha nism of the thick coalbeds developed in the fault basins in the Central Massif, France, but also show its features distinctively from those of the accumulation model of the traditional thick coalbeds.
María S. Japas
2008-06-01
. 35º- 40° obtenida en los afloramientos de la quebrada El Salto, se infiere en forma preliminar una importante componente sinestral durante la extensión en el tramo norte de la cuenca.Triassic clastic and volcanic rocks from the Precordillera were deposited in the Cuyana rift basin filling half-graben systems. Contractional/ transpressional Andean tectonics leads to the almost complete inversion of some portions of the basin which resulted in present-day isolated, structurally controlled outcrops of these Triassic rocks. In the Southern Precordillera both the degree of Neogene tectonic inversion and structural compexities are variable. At the regional scale, these variations in Andean deformation are related to first order anisotropies like the Cuyana basin borders and previous shear zones of Permian age (San Rafael orogenic phase. This paper focuses on the kinematic analysis done in the Cerro Manantial thrust sheet area (Cordón San Bartolo, central sector of the South Precordillera where tectonic inversion was not that strong and the influence of oblique strain zones is practically null. Four sets of extensional / transtensional faults were recognized affecting Triassic sedimentary rocks of the El Cielo Formation (Uspallata Group at the Quebrada El Salto. Fault displacements are of decimetric to metric scale. Mesoscopic kinematic indicators (en-échèlon tensional gashes, Riedel shear fractures, sigmoidal fractures were measured. Once Andean deformation was restored, a NNE direction for the Triassic extension was determined. Considering a northern branch of the Cuyana basin trending NNW (Az. 150° and oblique to the direction of extension (Az. 35-40°, a sinistral strike-slip component could be inferred for this portion of the basin.
The rift architecture and extensional tectonics of the South China Sea
Cameselle, Alejandra L.; Ranero, César R.; Barckhausen, Udo; Franke, Dieter
2016-04-01
Non-volcanic rifted continental margins are classically described as the product of lithospheric stretching and breakup leading to mantle exhumation, and subsequent seafloor spreading. However, recent studies question this model and indicate a wider range of structural evolutions, that challenge the existing model (e.g. Australia-Antarctic Rift System (Direen et al. 2007, 2011); the Tyrrhenian basin (Prada et al., 2014) or the South China Sea (Cameselle et al. 2015)). Rifting in the South China Sea developed from a series of extensional events, from early Eocene to Late Oligocene, resulting in a V-shape oceanic basin affected by the occurrence of several spreading centers, ridges, transform faults and post-spreading volcanism. In recent years, this marginal basin - the largest in East Asia - has increasingly become one of the key sites for the study of rifting and continental break-up. Its relative small size - compared to many classic, Atlantic-type continental margin settings - allows to easily match conjugated rifted margins and its relative youth promotes the preservation of its original nature. To examine the rifting evolution of the South China Sea, we have reprocessed with modern algorithms multichannel seismic profiles acquired during Sonne49 and BGR84 cruises across the three major subbasins: NW, SW and East subbasins. State-of-the-art of processing techniques have been used to increase the signal to noise ratio, including Tau-P and Wiener predictive deconvolution, multiple attenuation by both radon filtering and wave-equation-based surface-related multiple elimination (SRME) and time migration. To complement seismic interpretation, available vintage multichannel seismic data have been reprocessed with a post-stack flow, including Wiener deconvolution, FK-filtering, space and time variant band-pass filter and time migration. The improving quality of the seismic images shows a range of features including post-rift and syn-rift sediments, the structure of
Hips, Kinga; Haas, János; Győri, Orsolya
2016-06-01
Dolomitization of relatively thick carbonate successions occurs via an effective fluid circulation mechanism, since the replacement process requires a large amount of Mg-rich fluid interacting with the CaCO3 precursor. In the western end of the Neotethys, fault-controlled extensional basins developed during the Late Triassic spreading stage. In the Buda Hills and Danube-East blocks, distinct parts of silica and organic matter-rich slope and basinal deposits are dolomitized. Petrographic, geochemical, and fluid inclusion data distinguished two dolomite types: (1) finely to medium crystalline and (2) medium to coarsely crystalline. They commonly co-occur and show a gradual transition. Both exhibit breccia fabric under microscope. Dolomite texture reveals that the breccia fabric is not inherited from the precursor carbonates but was formed during the dolomitization process and under the influence of repeated seismic shocks. Dolomitization within the slope and basinal succession as well as within the breccia zones of the underlying basement block is interpreted as being related to fluid originated from the detachment zone and channelled along synsedimentary normal faults. The proposed conceptual model of dolomitization suggests that pervasive dolomitization occurred not only within and near the fault zones. Permeable beds have channelled the fluid towards the basin centre where the fluid was capable of partial dolomitization. The fluid inclusion data, compared with vitrinite reflectance and maturation data of organic matter, suggest that the ascending fluid was likely hydrothermal which cooled down via mixing with marine-derived pore fluid. Thermal gradient is considered as a potential driving force for fluid flow.
Extensional Tectonics Evidenced in Recent Sediments of Lake Van, Eastern Turkey
Sengul, M. Alper; Koral, Hayrettin; Elmas, M. Ali
2016-04-01
The Lake Van region is characterized by NE-SW trending faults with a left-lateral normal-slip component, NW-SE trending faults with a right-lateral normal-slip component and E-W trending reverse/thrust-slip faults, suggesting a N-S trending compressional stress orientation. Tectonic effects in the region continue to be manifested by recent seismicity as in the earthquake of October 23, 2011 (Mw=7.1). Although this earthquake has not produced many earthquake-related surface deformation, evidences of recent tectonics are rather extensive in the Quaternary sediments surrounding the lake. Therefore ages of sediments are important in determining the timing of tectonic activity. Optically stimulated luminescence (OSL) method was used to determine the age of lake sediments to the north of the lake. Also, shells of gastropods available in the sediments are dated by C14. Ages suggest that to the NE of Lake Van youngest activity on the NW-SE trending Erciş Fault with right-lateral normal-slip component is to be 34 ka. Activity on other normal faults in the same area is dated between 10-14 ka and 20 ka. Also, samewhat to the south of this region in vicinity of the Canik area, reverse faulting is dated to be younger than 40 ka. All ages indicate the region has been affected during the Pleistocene locally by an extensional regime contemporaneously with the contractional regime. The evidence of a one meter dip-slip displacement measured on a fault plane in a quarry supports the view of local extension in the NE sector of the lake. Key Words: Lake Van, OSL dating, neotectonics, active tectonics
Seton, M.; Zahirovic, S.; Müller, R.
2012-12-01
Although a number of tectonic reconstructions exist that document the development of the present-day complex assemblage of exotic terranes in Southeast Asia, very few describe the continuously evolving plate boundaries and the geodynamic driving forces in the region. We propose a plate motion model that attempts to reconcile evidence from both surface geology and the subsurface mantle structure, and implement continuously closing plate polygons using our open-source plate reconstruction software, GPlates, for the eastern Asian margin and eastern Tethyan domain since the Cretaceous. We link the change from a compressional to an extensional regime along eastern Asia in the Late Cretaceous as the likely opening of the Proto South China Sea in a back-arc setting to account for obducted ophiolite sections on Palawan that are Cretaceous in age, with a likely Miocene emplacement resulting from subduction of the Proto South China Sea crust. Such an interpretation is also consistent with the timing of accretionary episodes along northern Borneo and the upper mantle slab visible in P-wave seismic tomography models. The development of Sundaland is also intricately linked to the opening of the Proto South China Sea and the accretion of Gondwana-derived micro-continental blocks, including East Java and West Sulawesi, in the Cretaceous. Whether Sundaland behaved as a rigid cohesive block, or whether Borneo rotated and moved relative to Sundaland has been a matter of debate due to inconsistencies between paleomagnetic and structural data. Paleomagnetic results indicate significant rotations of Borneo that are accommodated by oroclinal bending without the need for bounding transform faults, which are not obvious in both seismic and potential field data. In the absence of preserved seafloor, we use geological evidence such as ophiolite emplacements, magmatic episodes, paleomagnetic constraints, structural reactivation and deformation as proxies to build a self-consistent plate
Inter-rifting Deformation in an Extensional Rift Segment; the Northern Volcanic Zone, Iceland
Pedersen, R.; Masterlark, T.; Sigmundsson, F.; Arnadottir, T.; Feigl, K. L.
2006-12-01
The Northern Volcanic Zone (NVZ) in Iceland is an extensional rift segment, forming a sub-aerial exposure of a part of the Mid-Atlantic ridge. The NVZ is bounded to the south by the Icelandic mantle plume, currently beneath the Vatnajökull ice cap, and to the north by the Tjörnes Fracture zone, a transform zone connecting the offset on- and offshore rift segments of the Mid-Atlantic ridge. Based on geologic and tectonic mapping, the NVZ has been divided into five partly overlapping en-echelon fissure swarms, each with a central main volcanic production area. The two fissure swarms with known activity in historic time are, based on geodetic and seismic data, interpreted to have associated shallow crustal magma chambers. These central volcanoes are furthermore the only with caldera collapses associated, reflecting on the maturity of the systems. A series of newly formed InSAR images of the NVZ, spanning the interval from 1993-2006, have been formed, revealing a complex interplay of several tectonic and magmatic processes. Deformation from two subsiding shallow sources appear at the sites of the known crustal magma chambers. Furthermore, subsidence is occurring at varying degrees within the associated relatively narrow fissure swarms (15-20 km). However, the horizontal plate spreading signal is not confined to the fissure systems, and appears to be distributed over a much wider zone (about 100 km). This wide zone of horizontal spreading has previously been measured with campaign GPS surveys. A broad area of uplift situated about 18 km to the north of one of the subsidence centres (Krafla) suggests a deep seated pressurization source near the crust mantle boundary. Movements on previously unrecognized faults are apparent in the data, correlating well with the location of earthquake epicentres from minor seismic activity. Finally, utilization of geothermal resources in the Krafla area affects the deformation fields created by magmatic and tectonic processes, further
Budhathoki, P.; Langford, R. P.; Pavlis, T. L.
2009-12-01
During the Jurassic and Cretaceous, the Chihuahua Trough formed an extensional basin, extending from the Gulf of Mexico to Southern Arizona, along the Present Border of the United States and Mexico. West of the Big Bend of Texas, Jurassic and Cretaceous sediments are less than 150 m thick, and in many areas are absent. The sedimentary package thickens to over 3km within the trough. The Albian Cox Sandstone is one of the most areally extensive formations and consists of interbedded fluvial coastal and shallow marine sandstones and shales. In this study area, shales (10-70 m) are thicker more than sandstone beds (2-10 m). This unit is overlain by Finlay formation, a fine crystalline gray limestone and underlain by Bluff Mesa formation, a fossiliferous shallow marine limestone. Cross-bedded, brown, fine to medium grained sandstone, interbedded with siltstone, shale and limestone are characteristic lithology of the Cox. The Indio Mountains of Trans-Pecos Texas offer an ideal location to study how this package accommodates the deformation associated with the subsiding Chihuahua trough. A continuous outcrop extends over 30 km oblique to the basin margin and thickens from approximately 375 m on the northern side to 437 m on the southern side of the 10 km section studied so far. One important mechanism is rotation of the strata into the basin, followed by truncation along sequence boundaries. The lower two sequence in the southern Indio mountains are rotated down to the basin relative to Finlay. The lowest sequences thicken from an erosional pinch out towards the South. Shale beds thicken within the rotated strata and accommodate some of the tilting. For example, Thickness of the shale bed varies from 18 m to 70 m within a 2 km distance. However, erosional truncation of the tilted strata accounts for most of the increases in thickness within sequences. The base of the formation has been rotated about 6 degrees south relative to the top of the formation. Another observed
OECD Maximum Residue Limit Calculator
With the goal of harmonizing the calculation of maximum residue limits (MRLs) across the Organisation for Economic Cooperation and Development, the OECD has developed an MRL Calculator. View the calculator.
吴志荣; 胡绪腾; 宋迎东
2013-01-01
工程中的大多构件承受着复杂的载荷形式,将单轴疲劳模型应用到多轴载荷情况已不能满足工程精度的要求,多轴载荷下的疲劳寿命计算日益引起人们的重视.基于临界平面的思想,结合Fatemi-Socie(FS)模型和Smith-Watson-Topper(SWT)参数各自的优点,提出一种新的多轴疲劳寿命预测模型.该模型以最大切应变幅与最大切应变幅平面上修正SWT参数的和作为多轴疲劳损伤控制参量,此参量可以同时考虑非比例附加循环硬化和平均应力对材料多轴疲劳寿命的影响,能同时适用于比例和非比例加载下的多轴疲劳问题.采用纯钛Ti、BT9钛合金、304不锈钢、S45C钢和1045HR钢5种材料多轴疲劳试验数据对提出的模型进行评估和验证,对几种材料比例和非比例加载下的多轴疲劳寿命预测结果大都分布在试验结果的2倍分散带之内,结果表明提出的多轴疲劳寿命模型具有较高的预测精度.%The most components of engineering structures are usually subjected to a complex loading. It is unable to meet the requirements of engineering precision if a uniaxial fatigue model is used under multi-axial loading. The calculation of fatigue life prediction under multiaxial loading causes people's attention more and more. A new multiaxial fatigue life prediction model is proposed based on the critical plane criteria. The model integrates the respective advantages of Fatemi-Socie(FS) model and Smith-Watson-Topper(SWT) parameter. The damage parameter in this model takes the sum of the maximum shear strain amplitude and the modified SWT parameter on the maximum shear strain amplitude plain. It can consider the effects of additional cyclic hardening due to non-proportional loading and mean stress on the multi-axial fatigue life of material. The proposed model can be applied to proportional and non-proportional loading. The model is evaluated by the multiaxial fatigue test data of pure titanium, BT9
Etheve, Nathalie; Frizon de Lamotte, Dominique; Mohn, Geoffroy; Martos, Raquel; Roca, Eduard; Blanpied, Christian
2016-07-01
Based on field work and seismic reflection data, we investigate the Cenozoic tectono-sedimentary evolution offshore and onshore Ibiza allowing the proposal of a new tectonic agenda for the region and its integration in the geodynamic history of the West Mediterranean. The late Oligocene-early Miocene rifting event, which characterizes the Valencia Trough and the Algerian Basin, located north and south of the study area respectively, is also present in Ibiza and particularly well-expressed in the northern part of the island. Among these two rifted basins initiated in the frame of the European Cenozoic Rift System, the Valencia Trough failed rapidly while the Algerian Basin evolved after as a back-arc basin related to the subduction of the Alpine-Maghrebian Tethys. The subsequent middle Miocene compressional deformation was localized by the previous extensional faults, which were either inverted or passively translated depending on their initial orientation. Despite the lateral continuity between the External Betics and the Balearic Promontory, it appears from restored maps that this tectonic event cannot be directly related to the Betic orogen, but results from compressive stresses transmitted through the Algerian Basin. A still active back-arc asthenospheric rise likely explains the stiff behavior of this basin, which has remained poorly deformed up to recent time. During the late Miocene a new extensional episode reworked the southern part of the Balearic Promontory. It is suggested that this extensional deformation developed in a trans-tensional context related to the westward translation of the Alboran Domain and the coeval right-lateral strike-slip movement along the Emile Baudot Escarpment bounding the Algerian Basin to the north.
Elitez, İrem; Yaltırak, Cenk; Aktuğ, Bahadır
2016-10-01
The tectonic framework of the eastern Mediterranean presented in this paper is based on an active subduction and small underwater hills/mountains on the oceanic crust moving toward the north. The Hellenic Arc, the Anaximander Mountains, the Rhodes and Finike basins, the compressional southern regions of the Western Taurides, and the extensional western Anatolian graben are the main interrelated tectonic structures that are shaped by the complex tectonic regimes. There are still heated debates regarding the structural properties and tectonic evolution of the southwestern Anatolia. GPS velocities and focal mechanisms of earthquakes demonstrate the absence of a single transform fault across the Burdur-Fethiye region; however, hundreds of small faults showing normal and left-lateral oblique slip indicate the presence of a regionally extensive shear zone in southwestern Turkey, which plays an important role in the eastern Mediterranean tectonics. The 300-km-long, 75-90-km-wide NE-SW-trending Burdur-Fethiye Shear Zone developed during the formation of Aegean back-arc extensional system and the thrusting of Western Taurides. Today, the left-lateral differential motion across the Burdur-Fethiye Shear Zone varies from 3 to 4 mm/yr in the north to 8-10 mm/yr in the south. This finding could be attributed to the fact that while the subduction of the African Plate is relatively fast beneath the western Anatolia at the Hellenic Trench, it is slow or locked beneath the Western Taurides. Therefore, the GPS vectors and their distributions on land indicate remarkable velocity differences and enable us to determine the left-lateral shear zone located between the extensional and compressional blocks. Furthermore, this active tectonic regime creates differences in topography. This study also demonstrates how deep structures, such as the continuation of the subduction transform edge propagator (STEP) fault between the Hellenic and Cyprus arcs in the continental area, can come into play
Tavani, Stefano; Corradetti, Amerigo; Billi, Andrea
2016-05-01
Image-based 3D modeling has recently opened the way to the use of virtual outcrop models in geology. An intriguing application of this method involves the production of orthorectified images of outcrops using almost any user-defined point of view, so that photorealistic cross-sections suitable for numerous geological purposes and measurements can be easily generated. These purposes include the accurate quantitative analysis of fault-fold relationships starting from imperfectly oriented and partly inaccessible real outcrops. We applied the method of image-based 3D modeling and orthorectification to a case study from the northern Apennines, Italy, where an incipient extensional fault affecting well-layered limestones is exposed on a 10-m-high barely accessible cliff. Through a few simple steps, we constructed a high-quality image-based 3D model of the outcrop. In the model, we made a series of measurements including fault and bedding attitudes, which allowed us to derive the bedding-fault intersection direction. We then used this direction as viewpoint to obtain a distortion-free photorealistic cross-section, on which we measured bed dips and thicknesses as well as fault stratigraphic separations. These measurements allowed us to identify a slight difference (i.e. only 0.5°) between the hangingwall and footwall cutoff angles. We show that the hangingwall strain required to compensate the upward-decreasing displacement of the fault was accommodated by this 0.5° rotation (i.e. folding) and coeval 0.8% thickening of strata in the hangingwall relatively to footwall strata. This evidence is consistent with trishear fault-propagation folding. Our results emphasize the viewpoint importance in structural geology and therefore the potential of using orthorectified virtual outcrops.
EVALUACIÓN DE LOS SISTEMAS DE ADMINISTRACIÓN DE BASES DE DATOS CON EXTENSIONES ESPACIALES
Malinowski Gadja, Elzbieta
2014-01-01
La práctica común para la creación de repositorios de datos espaciales es el uso de archivos shape, los cuales no proporcionan características necesarias para el control de consistencia de los datos, la redundancia o el acceso concurrente, entre otros. Por otra parte, las extensiones espaciales de los sistemas de administración de bases de datos (SABD) facilitan el uso de los mecanismos de controles declarativos o dinámicos (disparadores), aplicados a datos convencionales y espaciales. Sin em...
Tectónica extensional cretácica en la subcuenca de Oliete (Cordillera Ibérica central)
1997-01-01
The control of the extensional tectonics on the geometry of the Oliete Subbasin during Early Barremian-Basal Aptian (Early Cretaceous) is examinated. Both, the main NW-SE trending of the basin, its asymetrical geometry and the location of the depocenters was controlled by the reactivation of NW-SE and NE-SW Late Variscan faults, and the formation of new faults. We propose that the general geometry of the basin is controlled by a flexion in the cover, with some associated minor normal faults. ...
Stretching Behavior of Red Blood Cells at High Strain Rates
Mancuso, Jordan; Ristenpart, William
2016-11-01
Most work on the mechanical behavior of red blood cells (RBCs) has focused on simple shear flows. Relatively little work has examined RBC deformations in the physiologically important extensional flow that occurs at the entrance to a constriction. In particular, previous work suggests that RBCs rapidly stretch out and then retract upon entering the constriction, but to date no model predicts this behavior for the extremely high strain rates typically experienced there. In this work, we use high speed video to perform systematic measurements of the dynamic stretching behavior of RBCs as they enter a microfluidic constriction. We demonstrate that a simple viscoelastic model captures the observed stretching dynamics, up to strain rates as high as 1000 s-1. The results indicate that the effective elastic modulus of the RBC membrane at these strain rates is an order of magnitude larger than moduli measured by micropipette aspiration or other low strain rate techniques.
del Papa, Cecilia E.; Petrinovic, Ivan A.
2017-01-01
The Conglomerado Los Patos is a coarse-grained clastic unit that crops out irregularly in the San Antonio de los Cobres Valley in the Puna, Northwestern Argentina. It covers different units of the Cretaceous-Paleogene Salta Group by means of an angular unconformity and, in turn, is overlaid in angular unconformity by the Viscachayoc Ignimbrite (13 ± 0.3 Ma) or by late Miocene tuffs. Three lithofacies have been identified in the Corte Blanco locality; 1) Bouldery matrix-supported conglomerate (Gmm); 2) Clast-supported conglomerate (Gch) and 3) Imbricated clast-supported conglomerate (Gci). The stratigraphic pattern displays a general fining upward trend. The sedimentary facies association suggests gravitational flow processes and sedimentation in alluvial fan settings, from proximal to medial fan positions, together with a slope decrease upsection. Provenance studies reveal sediments sourced from Precambrian to Ordovician units located to the southwest, except for volcanic clasts in the Gmm facies that shows U/Pb age of 14.5 ± 0.5 Ma. This new age represents the maximum depositional age for the Conglomerado Los Patos, and it documents that deposition took place simultaneously during a period of increased tectonic and volcanic activity in the area. The structural analysis of the San Antonio de los Cobres Valley and the available thermochronological ages, indicate active N-S main thrusts and NW-SE transpressive and locally normal faults during the middle Miocene. In this context, we interpret the Conglomerado Los Patos to represent sedimentation in a small, extensional and short-lived basin associated with the compressional Andean setting.
Maximum margin Bayesian network classifiers.
Pernkopf, Franz; Wohlmayr, Michael; Tschiatschek, Sebastian
2012-03-01
We present a maximum margin parameter learning algorithm for Bayesian network classifiers using a conjugate gradient (CG) method for optimization. In contrast to previous approaches, we maintain the normalization constraints on the parameters of the Bayesian network during optimization, i.e., the probabilistic interpretation of the model is not lost. This enables us to handle missing features in discriminatively optimized Bayesian networks. In experiments, we compare the classification performance of maximum margin parameter learning to conditional likelihood and maximum likelihood learning approaches. Discriminative parameter learning significantly outperforms generative maximum likelihood estimation for naive Bayes and tree augmented naive Bayes structures on all considered data sets. Furthermore, maximizing the margin dominates the conditional likelihood approach in terms of classification performance in most cases. We provide results for a recently proposed maximum margin optimization approach based on convex relaxation. While the classification results are highly similar, our CG-based optimization is computationally up to orders of magnitude faster. Margin-optimized Bayesian network classifiers achieve classification performance comparable to support vector machines (SVMs) using fewer parameters. Moreover, we show that unanticipated missing feature values during classification can be easily processed by discriminatively optimized Bayesian network classifiers, a case where discriminative classifiers usually require mechanisms to complete unknown feature values in the data first.
Maximum Entropy in Drug Discovery
Chih-Yuan Tseng
2014-07-01
Full Text Available Drug discovery applies multidisciplinary approaches either experimentally, computationally or both ways to identify lead compounds to treat various diseases. While conventional approaches have yielded many US Food and Drug Administration (FDA-approved drugs, researchers continue investigating and designing better approaches to increase the success rate in the discovery process. In this article, we provide an overview of the current strategies and point out where and how the method of maximum entropy has been introduced in this area. The maximum entropy principle has its root in thermodynamics, yet since Jaynes’ pioneering work in the 1950s, the maximum entropy principle has not only been used as a physics law, but also as a reasoning tool that allows us to process information in hand with the least bias. Its applicability in various disciplines has been abundantly demonstrated. We give several examples of applications of maximum entropy in different stages of drug discovery. Finally, we discuss a promising new direction in drug discovery that is likely to hinge on the ways of utilizing maximum entropy.
无
2010-01-01
The Louzidian low-angle ductile shear detachment zone at the south of Chifeng is a SE-dipping, low-angle normal fault system. It is composed mainly of ductile shear zone, ductile-brittle shear zone and brittle fault zone. The ductile shear zone consists of, from bottom to top, mylonitic rocks, protomylonites and mylonites. Finite strain measurement of feldspar strain markers from those rocks using the Rf /φ method shows that strain intensities (Es) of the mylonite at core of the ductile shear zone (Es=0.65-0.96) are higher than those of the mylonitic rocks close to the granite intrusions (Es=0.59-0.62) and of the protomylonites at top of the ductile shear zone (Es= 0.47-0.70), and the strain types of the protomylonites and mylonties are elongate strain and plane-flattening strain, respectively. The kinematic vorticity values (Wk) estimated by the Polar Mohr diagram and the Rigid Grain Net range from 0.81 to 0.90 with an average of 0.85 for the protomylonites, and from 0.53 to 0.80 with 0.66 on average for the mylonites; Wk values of the extensional crenulation cleavage, i.e., C′, estimated by C′ method range from 0.63 to 0.37 with an average of 0.50. The angles between the maximum principal stress and shearing direction determined using the Maximum effective moment criterion evolved from 61° to 69° and to 75°, and finally normal to shearing direction. The results of strain and kinematic vorticity measurements suggest that high strain corresponds to low kinematic vorticity. Kinematic vorticity measurements show that the Louzidian low-angle ductile shear detachment zone is a result of a combination of simple-dominated general shearing at the early stage and pure-dominated general shearing at the late stage. All these, together with isotope geochronology and regional tectonic background, suggest that the Louzidian ductile shear detachment zone resulted from a combination of crust extension and magma intrusion. The model of simple shear at the early stage and
Barr, David
1985-10-01
Balanced cross-section techniques, and the construction of a restored section, permit 2-dimensional palinspastic restorations to be made in both compressional and extensional terraines. In 3 dimensions, an equivalent restoration can be made by assuming conservation of bedding-plane area and considering the volume of a stratigraphic interval rather than its cross-sectional area. Extensional basins displaying upper crustal listric normal faulting are particularly amenable to this approach. Computerised 3-D restorations have been made of the Inner Moray Firth basin, offshore Scotland. This basin is not isostatically compensated, and was produced by 7-8% post-Triassic extension, of which 2.5-3% is post-Jurassic, above a detachment surface at 20-25 km depth, close to the base of the crust. Limited lower crustal thinning (and lithospheric stretching) has affected the eastern part of the basin, but this can account for no more than half of the measured upper crustal extension. Some of this shallow extension is probably coupled by low-angle faults or shear zones into major zones of lithospheric stretching such as the North Sea grabens, where it may help account for discrepancies between estimates of lithospheric thinning and upper crustal extension.
Aguirre, L.; Féraud, G.; Morata, D.; Vergara, M.; Robinson, D.
1999-11-01
40Ar/ 39Ar ages were obtained from basaltic flows belonging to a 9-km-thick sequence generated in an extensional ensialic setting of an arc/back-arc basin type during the Early Cretaceous and presently exposed along the Coastal Range of central Chile. The basalts have been affected by very low- to low-grade burial metamorphism, mostly under prehnite-pumpellyite facies. Age values obtained from primary (volcanic) and secondary (metamorphic) minerals permit to quantify the time interval between volcanism and burial metamorphism. A plateau age of 119±1.2 Ma from primary plagioclase represents the best estimation of the age of the volcanism, whereas adularia, in low-variance assemblages contained in amygdules, gave a plateau age of 93.1±0.3 Ma which is interpreted as the age of the metamorphism. Considering the P- T conditions estimated for this metamorphic event, the c. 25 Ma time interval between volcanic emplacement and prehnite-pumpellyite facies metamorphism, the rate of basin subsidence in this extensional geodynamic setting would be comprised in the interval 150-180 m/Ma.
Bettison-Varga, Lori; Varga, Robert J.; Schiffman, Peter
1992-11-01
Field relations indicate that high-temperature hydrothermal circulation and accumulation of massive sulfide deposits within the Solea graben of the Troodos ophiolite, Cyprus, followed extreme crustal attenuation. Zones of pervasive, massive epidosite strike parallel to the axis of the Solea graben and to the strike of extensional normal faults. Initial fluid flow, evidenced by preferential epidotization in weakly altered areas surrounding massively altered regions, was focused along joints, microfractures, and (now) low-angle normal-fault zones related to graben formation. Permeability within the sheeted-dike section was enhanced by brittle deformation related to extensional structures as well as through volume reduction inherent in the diabase to epidosite mineralogic phase transformations. Intrusion of high-level gabbros into epidosite zones occurred both before and after significant amagmatic tectonic extension. Structural control on epidotization suggests that intrusion of late stocks into attenuated and highly deformed crust is necessary to drive the vigorous hydrothermal circulation that produced the epidosites and ore bodies of the Solea graben. A similar sequence of events is more likely to occur in the modern oceans along ridge crests with ephemeral magmatism, especially at intermediate- to slow-spreading ridges near transform faults.
Turco, Emilio; Barcz, Katarzyna; Rizzi, Nicola Luigi
2016-10-01
In dell'Isola et al. (Zeitschrift für Angewandte Math und Physik 66(6):3473-3498, 2015, Proc R Soc Lond A Math Phys Eng Sci 472(2185):1-23, 2016) pantographic sheets are proposed as a basic constituent for a novel metamaterial. In Part I, see Turco et al. (Zeitschrift für Angewandte Math und Physik, doi: 10.1007/s00033-016-0713-4, 2016), two different numerical models are applied in order to design an experimental setup aimed to prove the effectiveness of introduced concept. The aim of this paper is to prove that the Hencky-type model introduced for planar pantographic sheets allows for the correct prediction, in a large range of imposed displacements, of the experimental measurements concerning specimens undergoing coupled bending and extensional deformations. The four-parameter numerical model introduced is shown to have a large range of applicability: Indeed without changing the values of the material parameters previously attributed in simple extensional tests to a specific specimen by a best-fit procedure, it is possible to forecast its behavior in all the considered type of imposed deformations. The measurements performed include the determination of reactive forces exerted by used hard devices, and the numerical modeling is able to predict very carefully quantitatively and qualitatively also this complex aspect of phenomenology, where previously attempted models seem to have failed.
Wells, Michael L.; Beyene, Mengesha A.; Spell, Terry L.; Kula, Joseph L.; Miller, David M.; Zanetti, Kathleen A.
2005-09-01
The Pinto shear zone is one of several Late Cretaceous shear zones within the eastern fringe of the Mesozoic magmatic arc of the southwest Cordilleran orogen that developed synchronous with continued plate convergence and backarc shortening. We demonstrate an extensional origin for the shear zone by describing the shear-zone geometry and kinematics, hanging wall deformation style, progressive changes in deformation temperature, and differences in hanging wall and footwall thermal histories. Deformation is constrained between ˜74 and 68 Ma by 40Ar/ 39Ar thermochronology of the exhumed footwall, including multi-diffusion domain modeling of K-feldspar. We discount the interpretations, applied in other areas of the Mojave Desert region, that widespread Late Cretaceous cooling results from refrigeration due to subduction of a shallowly dipping Laramide slab or to erosional denudation, and suggest alternatively that post-intrusion cooling and exhumation by extensional structures are recorded. Widespread crustal melting and magmatism followed by extension and cooling in the Late Cretaceous are most consistent with production of a low-viscosity lower crust during anatexis and/or delamination of mantle lithosphere at the onset of Laramide shallow subduction.
Turco, Emilio; Barcz, Katarzyna; Pawlikowski, Marek; Rizzi, Nicola Luigi
2016-10-01
In dell'Isola et al. (Zeitschrift für Angewandte Math und Physik 66(6):3473-3498, 2015, Proc R Soc Lond A Math Phys Eng Sci 472(2185), 2016), the concept of pantographic sheet is proposed. The aim is to design a metamaterial showing: (i) a large range of elastic response; (ii) an extreme toughness in extensional deformation; (iii) a convenient ratio between toughness and weight. However, these required properties must coexist with non-detrimental mechanical characteristics in the presence of other kinds of imposed displacements. The aim of this paper is to prove via numerical simulations that pantographic sheets may effectively resist to coupled bending and extensional deformations. The four-parameter model introduced shows its versatility as it is able to encompass all the considered types of (large) deformations. The numerical integration scheme which we use is based on the same concepts exploited in Turco et al. (Zeitschrift für Angewandte Math und Physik 67(4):1-28, 2016): They prove that the Hencky-type discretization is very efficient also in nonlinear large deformations and large displacements regimes. In Part II of this paper, we will show that the used models are very effective to describe experimental evidence.
Greenslade, Thomas B., Jr.
1985-01-01
Discusses a series of experiments performed by Thomas Hope in 1805 which show the temperature at which water has its maximum density. Early data cast into a modern form as well as guidelines and recent data collected from the author provide background for duplicating Hope's experiments in the classroom. (JN)
Abolishing the maximum tension principle
Dabrowski, Mariusz P
2015-01-01
We find the series of example theories for which the relativistic limit of maximum tension $F_{max} = c^2/4G$ represented by the entropic force can be abolished. Among them the varying constants theories, some generalized entropy models applied both for cosmological and black hole horizons as well as some generalized uncertainty principle models.
Abolishing the maximum tension principle
Mariusz P. Da̧browski
2015-09-01
Full Text Available We find the series of example theories for which the relativistic limit of maximum tension Fmax=c4/4G represented by the entropic force can be abolished. Among them the varying constants theories, some generalized entropy models applied both for cosmological and black hole horizons as well as some generalized uncertainty principle models.
Research on extensional viscosity of liquid crystalline polymer%液晶高分子流体拉伸粘度的研究
付强
2006-01-01
The relationship between the extensional viscosity and material parameters is studied through the analytical formulas of stress and extensional viscosity derived from the constitutive equation, boundary conditions and the equation of motion of co-rotational Oldroyd fluid B model. By using software MATLAB, the differential equations are solved and the curves of extensional viscosity with other parameters are drawn, and the influence of these parameters on the rheologic behavior is shown.These results qualitatively agree with the experimental results.%利用液晶高分子共转Oldroyd流体B模型,研究了拉伸粘度的变化规律.作出了拉伸粘度随其它参数变化曲线.结论与实验结果一致.
Garcia-Senz, J.; Escuder-Viruete, J.; Perez-Estaun, A.
2012-12-01
In this study, we document a fault system in southeastern Dominican Republic that constitutes the onland continuation of the Mona Passage fault array. Fault-slip analysis has been carried out on 60 stations and paleostress ellipsoids were computed from striae orientations on faults using inverse methods. The CMT-catalog was also consulted to compare the moment tensor solution of earthquakes with the obtained results. Faults cut the 65-90 m raised coral-reef platform (Pliocene?-Pleistocene) that form the bulk of the Caribbean coastal plain, the 27-30 m reef terrace (247.2+26.3-20.05 ka, Middle Pleistocene), and the 6-7 m reef terrace (~125ka, Middle-Late Pleistocene boundary). Cumulative fault activity in the 65-90 m reef produced half-grabens with north polarity that controls the tributary water drainage. Their bounding faults attain 10-20 km wide and are segmented with transverse ramps developed at relay areas. The maximum throw calculated from fault scarps is about 75m. When represented in a length vs strike diagram, line scarps oriented in a prominent WNW set and a subordinate ENE set, in good agreement with field measurements of 540 fractures, that group into WNW, NNE and ENE sets. Paleostress analyses in tensional and hybrid fractures that affect the lower reef terraces indicate a SW-NE trend of subhorizontal extension. In the 65-90 m reef platform, the fault analysis establishes a stress ellipsoid characterized by a near-subvertical σ1 axis and a near-subhorizontal SSW to SW-trending σ3 axis. Therefore, the resulting type of brittle deformation in the Pleistocene ranges from (near) pure normal to normal strike-slip. In contrast, focal mechanisms solutions of generally deep (>65 km) earthquakes are characteristic of reverse, reverse oblique and strike-slip faulting, though shallow normal mechanisms also occur. The main stress axes determined by right-dihedra diagrams reveal a dominant N-trending subhorizontal compression and a subvertical extension. Assuming
Maximum Genus of Strong Embeddings
Er-ling Wei; Yan-pei Liu; Han Ren
2003-01-01
The strong embedding conjecture states that any 2-connected graph has a strong embedding on some surface. It implies the circuit double cover conjecture: Any 2-connected graph has a circuit double cover.Conversely, it is not true. But for a 3-regular graph, the two conjectures are equivalent. In this paper, a characterization of graphs having a strong embedding with exactly 3 faces, which is the strong embedding of maximum genus, is given. In addition, some graphs with the property are provided. More generally, an upper bound of the maximum genus of strong embeddings of a graph is presented too. Lastly, it is shown that the interpolation theorem is true to planar Halin graph.
Remizov, Ivan D
2009-01-01
In this note, we represent a subdifferential of a maximum functional defined on the space of all real-valued continuous functions on a given metric compact set. For a given argument, $f$ it coincides with the set of all probability measures on the set of points maximizing $f$ on the initial compact set. This complete characterization lies in the heart of several important identities in microeconomics, such as Roy's identity, Sheppard's lemma, as well as duality theory in production and linear programming.
The Testability of Maximum Magnitude
Clements, R.; Schorlemmer, D.; Gonzalez, A.; Zoeller, G.; Schneider, M.
2012-12-01
Recent disasters caused by earthquakes of unexpectedly large magnitude (such as Tohoku) illustrate the need for reliable assessments of the seismic hazard. Estimates of the maximum possible magnitude M at a given fault or in a particular zone are essential parameters in probabilistic seismic hazard assessment (PSHA), but their accuracy remains untested. In this study, we discuss the testability of long-term and short-term M estimates and the limitations that arise from testing such rare events. Of considerable importance is whether or not those limitations imply a lack of testability of a useful maximum magnitude estimate, and whether this should have any influence on current PSHA methodology. We use a simple extreme value theory approach to derive a probability distribution for the expected maximum magnitude in a future time interval, and we perform a sensitivity analysis on this distribution to determine if there is a reasonable avenue available for testing M estimates as they are commonly reported today: devoid of an appropriate probability distribution of their own and estimated only for infinite time (or relatively large untestable periods). Our results imply that any attempt at testing such estimates is futile, and that the distribution is highly sensitive to M estimates only under certain optimal conditions that are rarely observed in practice. In the future we suggest that PSHA modelers be brutally honest about the uncertainty of M estimates, or must find a way to decrease its influence on the estimated hazard.
Alternative Multiview Maximum Entropy Discrimination.
Chao, Guoqing; Sun, Shiliang
2016-07-01
Maximum entropy discrimination (MED) is a general framework for discriminative estimation based on maximum entropy and maximum margin principles, and can produce hard-margin support vector machines under some assumptions. Recently, the multiview version of MED multiview MED (MVMED) was proposed. In this paper, we try to explore a more natural MVMED framework by assuming two separate distributions p1( Θ1) over the first-view classifier parameter Θ1 and p2( Θ2) over the second-view classifier parameter Θ2 . We name the new MVMED framework as alternative MVMED (AMVMED), which enforces the posteriors of two view margins to be equal. The proposed AMVMED is more flexible than the existing MVMED, because compared with MVMED, which optimizes one relative entropy, AMVMED assigns one relative entropy term to each of the two views, thus incorporating a tradeoff between the two views. We give the detailed solving procedure, which can be divided into two steps. The first step is solving our optimization problem without considering the equal margin posteriors from two views, and then, in the second step, we consider the equal posteriors. Experimental results on multiple real-world data sets verify the effectiveness of the AMVMED, and comparisons with MVMED are also reported.
Roldán, Francisco J.; Azañón, Jose Miguel; Rodríguez-Fernández, Jose; María Mateos, Rosa
2016-04-01
The Guadalquivir Basin (Upper Tortonian-Quaternary sedimentary infilling) has been considered the foreland basin of the Betic Orogen built up during its collision with the Sudiberian margin. The basin is currently restricted to its westernmost sector, in the Cadiz Gulf, because the Neogene-Quaternary uplift of the Betic Cordillera has produced the emersion of their central and eastern parts. The upper Tortonian chronostratigraphic unit is the oldest one and it was indistinctly deposited on the South Iberian paleomargin and the External units from the Betic Cordillera. However, these rocks are undeformed on the Sudiberian paleomargin while they are deeply affected by brittle deformation on the External Betic Zone. Outcrops of Upper Tortonian sedimentary rocks on External Betic Zone are severely fragmented showing allocthonous characters with regard to those located on the Sudiberian paleomargin. This post- Upper Tortonian deformation is not well known in the External Zones of the Cordillera where the most prominent feature is the ubiquity of a highly deformed tecto-sedimentary unit outcropping at the basement of the Guadalquivir sedimentary infilling. This tecto-sedimentary unit belongs to the Mass Wasting Extensional Complex (Rodríguez-Fernández, 2014) formed during the collision and westward migration of the Internal Zone of the Betic Cordillera (15-8,5 Ma). In the present work, we show an ensemble of tectonic, geophysical and cartographic data in order to characterize the post-Upper Tortonian deformation. For this, seismic reflection profiles have been interpreted with the help of hidrocarbon boreholes to define the thickness of the Upper Tortonian sedimentary sequence. All these data provide an estimation of the geometrical and kinematic characteristics of the extensional faults, direction of movement and rate of displacement of these rocks during Messinian/Pliocene times. References Rodríguez-Fernández, J., Roldan, F. J., J.M. Azañón y Garcia-Cortes, A
Caroline J.S. Gomes
2006-06-01
Full Text Available Analogue experiments were carried out to get insights into the processes governing positive inversion during the foreland propagating thrust tectonics in the southern Serra do Espinhaço, a Brasiliano/Panafrican foldthrust belt in southeast Brazil. In particular, model listric half-grabens were inverted by applying contractional displacement to the footwall blocks. We investigated two different inversion conditions in listric half-grabens: (i extensional and contractional detachments at the same level and (ii at different positions. The models revealed that the development of a forward-breaking thrust system occurs in the basin synrift deposits, by contractional translation of the extensional footwall block when the extensional and contractional master faults do not coincide. Our experiments show the tectonic imbrication between basement and synrift sequences which characterizes the southern Serra do Espinhaço, and support the location in the eastern mountain range domain of the Espinhaço rift master fault system, which is not exposed at the surface.Em experimentos de areia foi simulada a inversão positiva com o intuito de investigar os processos que governam a tectônica da Cordilheira do Espinhaço Meridional na borda sudeste do Cráton São Francisco. Analisou-se, em particular, a evolução progressiva de hemigrabens, com falha de borda lístrica, na qual o fechamento da bacia ocorreu através da translação do bloco do muro da falha mestra. Duas condições foram investigadas: (i os descolamentos distensivos e compressivos ocorrem na mesma cota e (ii os descolamentos situam-se em posições diferentes. Os modelos revelaram que um sistema de falhas de cavalgamento com estilo colapso da lapa se desenvolve no interior do depósito sinrift quando os descolamentos não coincidem. O imbricamento entre escamas do pré- e sinrift, nos modelos, permite esboçar uma analogia com a tectônica da porção sul da Cordilheira do Espinhaço e situar a
Huang, Shu; Yee, Wu Aik; Tjiu, Wuiwui Chauhari; Liu, Ye; Kotaki, Masaya; Boey, Yin Chiang Freddy; Ma, Jan; Liu, Tianxi; Lu, Xuehong
2008-12-02
Polyvinylidene difluoride (PVDF) solutions containing a very low concentration of single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) of similar surface chemistry, respectively, were electrospun, and the nanofibers formed were collected using a modified rotating disk collector. The polymorphic behavior and crystal orientation of the nanofibers were studied using wide-angle X-ray diffraction and infrared spectroscopy, while the nanotube alignment and interfacial interactions in the nanofibers were probed by transmission electron microscopy and Raman spectroscopy. It is shown that the interfacial interaction between the SWCNTs and PVDF and the extensional force experienced by the nanofibers in the electrospinning and collection processes can work synergistically to induce highly oriented beta-form crystallites extensively. In contrast, the MWCNTs could not be well aligned along the nanofiber axis, which leads to a lower degree of crystal orientation.
Broniarz-Press, L; Sosnowski, T R; Matuszak, M; Ochowiak, M; Jabłczyńska, K
2015-05-15
The paper contains results of the experimental study on atomization process of aqueous solutions of glycerol and aqueous solutions of glycerol-polyacrylamide (Rokrysol WF1) in an ultrasonic inhaler. In experiments the different concentration aqueous solutions of glycerol and glycerol-polyacrylamide have been tested. The results have been obtained by the use of laser diffraction technique. The differences between characteristics of ultrasonic atomization for test liquids have been observed. The analysis of drop size histograms shows that the different sizes of drops have been formed during atomization process. The present study confirmed the previous reports which suggested that the drops size changes with the increase in viscosity of solution changes in spray characteristics were also observed. It has been shown that the shear and extensional viscosities affect the process of atomization.
Cacti with maximum Kirchhoff index
Wang, Wen-Rui; Pan, Xiang-Feng
2015-01-01
The concept of resistance distance was first proposed by Klein and Randi\\'c. The Kirchhoff index $Kf(G)$ of a graph $G$ is the sum of resistance distance between all pairs of vertices in $G$. A connected graph $G$ is called a cactus if each block of $G$ is either an edge or a cycle. Let $Cat(n;t)$ be the set of connected cacti possessing $n$ vertices and $t$ cycles, where $0\\leq t \\leq \\lfloor\\frac{n-1}{2}\\rfloor$. In this paper, the maximum kirchhoff index of cacti are characterized, as well...
Generic maximum likely scale selection
Pedersen, Kim Steenstrup; Loog, Marco; Markussen, Bo
2007-01-01
The fundamental problem of local scale selection is addressed by means of a novel principle, which is based on maximum likelihood estimation. The principle is generally applicable to a broad variety of image models and descriptors, and provides a generic scale estimation methodology. The focus...... on second order moments of multiple measurements outputs at a fixed location. These measurements, which reflect local image structure, consist in the cases considered here of Gaussian derivatives taken at several scales and/or having different derivative orders....
Economics and Maximum Entropy Production
Lorenz, R. D.
2003-04-01
Price differentials, sales volume and profit can be seen as analogues of temperature difference, heat flow and work or entropy production in the climate system. One aspect in which economic systems exhibit more clarity than the climate is that the empirical and/or statistical mechanical tendency for systems to seek a maximum in production is very evident in economics, in that the profit motive is very clear. Noting the common link between 1/f noise, power laws and Self-Organized Criticality with Maximum Entropy Production, the power law fluctuations in security and commodity prices is not inconsistent with the analogy. There is an additional thermodynamic analogy, in that scarcity is valued. A commodity concentrated among a few traders is valued highly by the many who do not have it. The market therefore encourages via prices the spreading of those goods among a wider group, just as heat tends to diffuse, increasing entropy. I explore some empirical price-volume relationships of metals and meteorites in this context.
Objects of maximum electromagnetic chirality
Fernandez-Corbaton, Ivan
2015-01-01
We introduce a definition of the electromagnetic chirality of an object and show that it has an upper bound. The upper bound is attained if and only if the object is transparent for fields of one handedness (helicity). Additionally, electromagnetic duality symmetry, i.e. helicity preservation upon scattering, turns out to be a necessary condition for reciprocal scatterers to attain the upper bound. We use these results to provide requirements for the design of such extremal scatterers. The requirements can be formulated as constraints on the polarizability tensors for dipolar scatterers or as material constitutive relations. We also outline two applications for objects of maximum electromagnetic chirality: A twofold resonantly enhanced and background free circular dichroism measurement setup, and angle independent helicity filtering glasses.
Maximum mutual information regularized classification
Wang, Jim Jing-Yan
2014-09-07
In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.
The strong maximum principle revisited
Pucci, Patrizia; Serrin, James
In this paper we first present the classical maximum principle due to E. Hopf, together with an extended commentary and discussion of Hopf's paper. We emphasize the comparison technique invented by Hopf to prove this principle, which has since become a main mathematical tool for the study of second order elliptic partial differential equations and has generated an enormous number of important applications. While Hopf's principle is generally understood to apply to linear equations, it is in fact also crucial in nonlinear theories, such as those under consideration here. In particular, we shall treat and discuss recent generalizations of the strong maximum principle, and also the compact support principle, for the case of singular quasilinear elliptic differential inequalities, under generally weak assumptions on the quasilinear operators and the nonlinearities involved. Our principal interest is in necessary and sufficient conditions for the validity of both principles; in exposing and simplifying earlier proofs of corresponding results; and in extending the conclusions to wider classes of singular operators than previously considered. The results have unexpected ramifications for other problems, as will develop from the exposition, e.g. two point boundary value problems for singular quasilinear ordinary differential equations (Sections 3 and 4); the exterior Dirichlet boundary value problem (Section 5); the existence of dead cores and compact support solutions, i.e. dead cores at infinity (Section 7); Euler-Lagrange inequalities on a Riemannian manifold (Section 9); comparison and uniqueness theorems for solutions of singular quasilinear differential inequalities (Section 10). The case of p-regular elliptic inequalities is briefly considered in Section 11.
Shear and Extensional Rheometry of PDMS Tamponade Agents Used in Vitroretinal Surgery
Day, Michael; Blanchard, Rowan-Louise; English, Rob; Dobbie, Tom; Williams, Rachel; Garvey, Michael; Wong, David
2008-07-01
The emulsification of low molar mass silicone oil (PDMS)-based tamponade agents used in the treatment of complex retinal detachments is a significant clinical problem leading to the patient suffering impairment of vision whilst the tamponade is in place. This is particularly the case in temporal postoperative applications where the tamponade can remain in the ocular cavity for several months. The majority of clinicians prefer to use a PDMS fluid of kinematic viscosity 1000 cS, which offers ease of manual injection. Work is progressing towards the development of tamponades with a reduced tendency to emulsify, through specific tailoring of rheology and interfacial properties. Greater knowledge of the mechanism of intraocular emulsification is being elucidated and has led to the development of `polymer modified' tamponades with enhanced performance. Such materials are formulated by the addition of a high molecular weight PDMS to the base PDMS fluid. Measurement of the shear viscosity at moderate shear rates is useful in predicting performance during manual injection into the eye. However, the determination of the behaviour in both shear and extension at high strain rates is useful in predicting resistance to intraocular emulsification and in informing future modeling studies. Initial experiments focused on rotational rheometry (shear) and capillary breakup rheometry (CaBER—extension). A range of polymer modified tamponades were characterised—based on PDMS base oils from 100-5000 cS and containing up to 30% by weight PDMS of molecular weight varying in the range 100-800 kDa. Even though the volume occupancy of the polymeric additive ranged from dilute to significantly interpenetrated, a linear response was observed in each case. However, subsequent experiments using capillary rheometry lead to the observation of non-linear behaviour and significant differences in the type of response. Systems with enhanced high strain rate tensile viscosities gave improved
Hans-Joachim Radusch
2013-07-01
Full Text Available Elongational flow properties of polymer melts are very important for numerous polymer processing technologies such as blown film extrusion or foam extrusion. Rheotens tests were conducted to investigate the influence of plasticizer content on elongational flow properties of cellulose acetate (CA. Triethyl citrate (TEC was used as plasticizer. Melt strength decreases whereas melt extensibility increases with increasing plasticizer content. Melt strength was further studied as a function of zero shear viscosity. The typical draw resonance of the Rheotens curve shifts to higher drawdown velocity and the amplitude of the draw resonance decreases with increasing TEC content. With respect to foam extrusion, not only are melt strength and melt extensibility important but the elongational behavior at low strain rates and the area under the Rheotens curve are also significant. Therefore, elongational viscosity as well as specific energy input were calculated and investigated with respect to plasticizer content. Preliminary foam extrusion tests of externally plasticized CA using chemical blowing agents confirm the results from rheological characterization.
Maximum entropy production in daisyworld
Maunu, Haley A.; Knuth, Kevin H.
2012-05-01
Daisyworld was first introduced in 1983 by Watson and Lovelock as a model that illustrates how life can influence a planet's climate. These models typically involve modeling a planetary surface on which black and white daisies can grow thus influencing the local surface albedo and therefore also the temperature distribution. Since then, variations of daisyworld have been applied to study problems ranging from ecological systems to global climate. Much of the interest in daisyworld models is due to the fact that they enable one to study self-regulating systems. These models are nonlinear, and as such they exhibit sensitive dependence on initial conditions, and depending on the specifics of the model they can also exhibit feedback loops, oscillations, and chaotic behavior. Many daisyworld models are thermodynamic in nature in that they rely on heat flux and temperature gradients. However, what is not well-known is whether, or even why, a daisyworld model might settle into a maximum entropy production (MEP) state. With the aim to better understand these systems, this paper will discuss what is known about the role of MEP in daisyworld models.
Maximum stellar iron core mass
F W Giacobbe
2003-03-01
An analytical method of estimating the mass of a stellar iron core, just prior to core collapse, is described in this paper. The method employed depends, in part, upon an estimate of the true relativistic mass increase experienced by electrons within a highly compressed iron core, just prior to core collapse, and is signiﬁcantly different from a more typical Chandrasekhar mass limit approach. This technique produced a maximum stellar iron core mass value of 2.69 × 1030 kg (1.35 solar masses). This mass value is very near to the typical mass values found for neutron stars in a recent survey of actual neutron star masses. Although slightly lower and higher neutron star masses may also be found, lower mass neutron stars are believed to be formed as a result of enhanced iron core compression due to the weight of non-ferrous matter overlying the iron cores within large stars. And, higher mass neutron stars are likely to be formed as a result of fallback or accretion of additional matter after an initial collapse event involving an iron core having a mass no greater than 2.69 × 1030 kg.
Maximum Matchings via Glauber Dynamics
Jindal, Anant; Pal, Manjish
2011-01-01
In this paper we study the classic problem of computing a maximum cardinality matching in general graphs $G = (V, E)$. The best known algorithm for this problem till date runs in $O(m \\sqrt{n})$ time due to Micali and Vazirani \\cite{MV80}. Even for general bipartite graphs this is the best known running time (the algorithm of Karp and Hopcroft \\cite{HK73} also achieves this bound). For regular bipartite graphs one can achieve an $O(m)$ time algorithm which, following a series of papers, has been recently improved to $O(n \\log n)$ by Goel, Kapralov and Khanna (STOC 2010) \\cite{GKK10}. In this paper we present a randomized algorithm based on the Markov Chain Monte Carlo paradigm which runs in $O(m \\log^2 n)$ time, thereby obtaining a significant improvement over \\cite{MV80}. We use a Markov chain similar to the \\emph{hard-core model} for Glauber Dynamics with \\emph{fugacity} parameter $\\lambda$, which is used to sample independent sets in a graph from the Gibbs Distribution \\cite{V99}, to design a faster algori...
Roldán, Francisco Javier; Azañon, Jose Miguel; Rodríguez, Jose; Mateos, Rosa Maria
2014-05-01
The synthesis and correlation of units carried out in the continuous geological map (Roldán et al., 2012), has revealed a fragmentation of the carbonate outcrops belong to the Subbetic Domain (García-Hernández et al., 1980). Subbetic NW verging thrust and fold axial traces have not lateral continuity and Jurassic carbonate outscrops appear as klippes on the olistotromic unit. These ductile structures that can be observed in the internal structure of these jurassic blocks are unrelated to the brittle-ductile deformation bands observed at the basal pelitic levels. Basal detachments are rooted in: a) the Olistostromic unit, a Upper Langhian-Lower Serravallian breccia constituted by gypsum-bearing clay and marls; b) Cretaceous-Tertiary marly sedimentary rocks (Rodríguez-Fernández, et al., 2013) . In both kind of rocks, cataclastic structures allows to infer a top-to-the WSW displacement. Paleostress measurements, made on these detachments levels, are compatible with a extensional regime (Roldán et al., 2012). At the same time, the analysis and interpretation of subsurface data (seismic surveys and borehole testing) shows that the Subbetic Domain (External Subbetic, Molina 1987) are affected by westward low-angle normal faults. A balanced cross-section, based on morphological and cartographic data in the area between Sierra de Cabra and Sierra de Alta Coloma (Valdepeñas de Jaén), shows plurikilometric displacements which has been produced during Late Serravallian-Early Tortonian times. References: García-Hernández, M., López-Garrido, A.C., Rivas, P., Sanz de Galdeano, C., Vera, J.A. (1980): Mesozoic paleogeographic evolution of the zones of the Betic Cordillera. Geol. Mijnb. 59 (2). 155-168. Molina, J.M. (1987). Análisis de facies del Mesozoico en el Subbético. Tesis Doctoral, Univ. Granada. 518 p. Rodríguez-Fernández, J., Roldán, F. J., Azañón, J.M. y García-Cortés, A. (2013). El colapso gravitacional del frente orogénico a lpino en el Dominio Subb
2011-01-10
...: Establishing Maximum Allowable Operating Pressure or Maximum Operating Pressure Using Record Evidence, and... facilities of their responsibilities, under Federal integrity management (IM) regulations, to perform... system, especially when calculating Maximum Allowable Operating Pressure (MAOP) or Maximum Operating...
Jordan, T. E.; Mpodozis, C.; Blanco, N.; Pananont, P.; Dávila, F.
2004-12-01
The Salar de Atacama Basin (SdAB) is the largest and most persistent sedimentary basin of northern Chile, accumulating nonmarine sediment from Cretaceous to modern times. Its northwestern neighbor, the Calama, was a Cenozoic basin. Although SdAB was in the backarc zone early in the Andean orogeny, both are now forearc basins. Others demonstrated that the basins overlie anomalously cold, strong, and dense crust and lithosphere. We focus on an extensional Oligocene basin stage. Interpretation of the basin-controlling faults is based on seismic reflection studies supported by field relations. The SdAB is limited to the west by the NNE-trending, steeply east-dipping, Paciencia Fault (PF). The PF experienced 5-7 km of down-to-the-east offset during the Oligocene-early Miocene. Syntectonic strata, an arid succession of siliciclastics and evaporites, are asymmetric, with thicknesses of 5000 m and abundant halite adjacent to the PF, and of 1000 m with fine detrital clastic strata 25 km farther east. Relations in conglomeratic growth strata that overlap the PF also demonstrate normal displacement during sediment accumulation. Seismic data reveal that a buried normal fault with 1-1.5 km down-to-the-east displacement limits the western margin of the Oligocene-Miocene Calama siliciclastic basin fill. Regionally, Oligocene-early Miocene margin-parallel strike-slip deformation dominated northwest of the basins, contributing sinistral offset (West Fissure Fault) to the northern segment of the long-lived Domeyko Fault System. The new SdAB and Calama data reveal that a 20,000 km2 domain of extensional basins existed within the dominantly strike-slip region. Even if PF and the fault in the Calama Basin were transtensional, the proportion of extension to strike-slip displacement is much greater in these basins than elsewhere in northern Chile. Further study is required to understand what combination of factors caused this kinematic distinction as well as delayed the onset of CVZ
Rosas-Elguera, J.; Ferrari, L.; Delgado, M.; Uribe, A.; Valdivia, L.; Castillo, R.
2003-12-01
In the past decade much debate has centered upon the kinematics and the mechanism of continental deformation in western Mexico and the motion of the Jalisco block relative to North America. Two distinct models have been proposed. The first one suggest a NW-motion of the Jalisco block that would implies a right-lateral faulting along the Tepic-Zacoalco rift (TZR). More recently others authors have documented a N-NE extensional tectonics active since late Miocene and suggested that the continental boundaries of the Jalisco block, are older structures reactivated by plate boundary forces. Studies on the crustal seismicity and the kinematics of Quaternary faults provide another constraint on the direction of motion between the Jalisco block and North America. On November 4, 5, 6, and 7, 1995, one month after the October 09, 1995, Manzanillo earthquake (Mw = 8.0), a swarm of small events was felt in the Amatlan de Ca¤as half-graben and recorded by the regional seismic network of Comision Federal de Electricidad. The coda magnitude of the largest event was Mc = 2.5-3.6 and the events were located depth ranging from 6 to 10 km. This seismic activity provoked that people from Pie de la Cuesta and Yerbabuena villages were evacuated. After that a seismic station equipped with an analogic seismograph MEQ-800 at Pie de la Cuesta was installed for three months. During the same time, October, 1995, some houses distributed along a WNW trend in Ameca city underwent severe damages, they are. The digital elevations model of the Ameca city suggest that several structures tectonics are shorter than 2 km are present in the area. The present direction of motion of the Rivera plate relative to North America plate along Middle America Trench has been estimated between N19° E to N48° E (e.g. Bandy et al., 1996). During the October 09, 1995, subduction-related earthquake (Mw = 8.0) a GPS network recorded a SW motion of the Jalisco block which could be associated to an elastic deformation
Lafuente, P.; Arlegui, L. E.; Liesa, C. L.; Simón, J. L.
2011-10-01
The Concud fault is a 13.5 km long, NW-SE striking normal fault at the eastern Iberian Chain. Its recent (Late Pleistocene) slip history is characterized from mapping and trench analysis and discussed in the context of the accretion/incision history of the Alfambra River. The fault has been active since Late Pliocene times, with slip rates ranging from 0.07 to 0.33 mm/year that are consistent with its present-day geomorphologic expression. The most likely empirical correlation suggests that the associated paleoseisms have potential magnitudes close to 6.8, coseismic displacements of 2.0 m, and recurrence intervals from 6.1 to 28.9 ka. At least six paleoseismic events have been identified between 113 and 32 ka. The first three events (U to W) involved displacement along the major fault plane. The last three events (X to Z) encompassed downthrow and hanging-wall synthetic bending prompting fissure opening. This change is accompanied by a decrease in slip rate (from 0.63 to 0.08-0.17 mm/year) and has been attributed to activation of a synthetic blind fault at the hanging wall. The average coseismic displacement (1.9-2.0 m) and recurrence period (6.7-7.9 ka) inferred from this paleoseismic succession are within the ranges predicted from empirical correlation. Such paleoseismic activity contrasts with the moderate present-day seismicity of the area (maximum instrumental Mb = 4.4), which can be explained by the long recurrence interval that characterizes intraplate regions.
The Sherpa Maximum Likelihood Estimator
Nguyen, D.; Doe, S.; Evans, I.; Hain, R.; Primini, F.
2011-07-01
A primary goal for the second release of the Chandra Source Catalog (CSC) is to include X-ray sources with as few as 5 photon counts detected in stacked observations of the same field, while maintaining acceptable detection efficiency and false source rates. Aggressive source detection methods will result in detection of many false positive source candidates. Candidate detections will then be sent to a new tool, the Maximum Likelihood Estimator (MLE), to evaluate the likelihood that a detection is a real source. MLE uses the Sherpa modeling and fitting engine to fit a model of a background and source to multiple overlapping candidate source regions. A background model is calculated by simultaneously fitting the observed photon flux in multiple background regions. This model is used to determine the quality of the fit statistic for a background-only hypothesis in the potential source region. The statistic for a background-plus-source hypothesis is calculated by adding a Gaussian source model convolved with the appropriate Chandra point spread function (PSF) and simultaneously fitting the observed photon flux in each observation in the stack. Since a candidate source may be located anywhere in the field of view of each stacked observation, a different PSF must be used for each observation because of the strong spatial dependence of the Chandra PSF. The likelihood of a valid source being detected is a function of the two statistics (for background alone, and for background-plus-source). The MLE tool is an extensible Python module with potential for use by the general Chandra user.
Vestige: Maximum likelihood phylogenetic footprinting
Maxwell Peter
2005-05-01
Full Text Available Abstract Background Phylogenetic footprinting is the identification of functional regions of DNA by their evolutionary conservation. This is achieved by comparing orthologous regions from multiple species and identifying the DNA regions that have diverged less than neutral DNA. Vestige is a phylogenetic footprinting package built on the PyEvolve toolkit that uses probabilistic molecular evolutionary modelling to represent aspects of sequence evolution, including the conventional divergence measure employed by other footprinting approaches. In addition to measuring the divergence, Vestige allows the expansion of the definition of a phylogenetic footprint to include variation in the distribution of any molecular evolutionary processes. This is achieved by displaying the distribution of model parameters that represent partitions of molecular evolutionary substitutions. Examination of the spatial incidence of these effects across regions of the genome can identify DNA segments that differ in the nature of the evolutionary process. Results Vestige was applied to a reference dataset of the SCL locus from four species and provided clear identification of the known conserved regions in this dataset. To demonstrate the flexibility to use diverse models of molecular evolution and dissect the nature of the evolutionary process Vestige was used to footprint the Ka/Ks ratio in primate BRCA1 with a codon model of evolution. Two regions of putative adaptive evolution were identified illustrating the ability of Vestige to represent the spatial distribution of distinct molecular evolutionary processes. Conclusion Vestige provides a flexible, open platform for phylogenetic footprinting. Underpinned by the PyEvolve toolkit, Vestige provides a framework for visualising the signatures of evolutionary processes across the genome of numerous organisms simultaneously. By exploiting the maximum-likelihood statistical framework, the complex interplay between mutational
Growth of group II Clostridium botulinum strains at extreme temperatures.
Derman, Yağmur; Lindström, Miia; Selby, Katja; Korkeala, Hannu
2011-11-01
The minimum and maximum growth temperatures and the maximum growth rates at 10, 30, 37, and 40°C were determined for 24 group II Clostridium botulinum strains. Genetic diversity of the strains was revealed by amplified fragment length polymorphism (AFLP) analysis. The minimum growth temperatures ranged from 6.2 to 8.6°C, and the maximum growth temperatures ranged from 34.7 to 39.9°C. The mean maximum growth temperatures and mean maximum growth rates of type E strains at 37°C were significantly higher than those of type B and type F strains. A significant correlation between maximum growth rates at 37°C and maximum growth temperatures was found for all strains. Some type E strains with a high minimum growth temperature also had a higher maximum growth rate at 37°C than at 30°C, which suggests that some group II C. botulinum strains are more mesophilic in their growth properties than others. We found relatively small differences between AFLP clusters, indicating that diverse genetic background among the strains was not reflected in the growth properties. The growth characteristics of group II C. botulinum and some type E strains with mesophilic growth properties may have an impact on inoculation studies and predictive modeling for assessing the safety of foods.
Velasque, P. C.; Ducasse, L.; Muller, J.; Scholten, R.
1989-05-01
A geotraverse, constructed on the basis of surface and subsurface data across the Basque-Béarnais portion of the Pyrenees, east of the Pamplona fault, reveals, from north to south, the existence of three major tectono-sedimentary units: the North Pyrenean Zone (NPZ), the Central Zone (CZ) and the Axial Zone (AZ). These zones are characterized both by the type and age of their sediments and volcanics, and by the style of their Cretaceous synsedimentary structures. Paleogeographically, they correspond to a Cretaceous platform (AZ), margin (CZ) and basin (NPZ), separated by zones of normal faults. During Alpine convergence, the Cretaceous fault system was to varying degrees reactivated in the reverse sense. The NPZ grades into the CZ without any significant hiatus. By contrast, the CZ is separated from the AZ by a major southward overthrust, the Orly-Lakhoura overthrust, which shows up as the most important fault in the cross-section. Its subsurface continuation is constrained by regional microseismicity and other seismic data. All these data lead us to consider the Orhy-Lakhoura overthrust as the surface evidence of the Alpine crustal underthrust of Iberia below the European continental domain. Restoration of the cross-section suggests that this Alpine underthrust follows a previous crustal discontinuity linked to the Cretaceous extensional episode.
Bhattacharjee, P K; McDonnell, A G; Prabhakar, R; Yeo, L Y; Friend, J, E-mail: james.friend@monash.edu.au [MicroNanophysics Research Laboratory, Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC 3800 (Australia); Melbourne Centre for Nanofabrication, Melbourne, VIC 3800 (Australia)
2011-02-15
Forming capillary bridges of low-viscosity ({approx}<10 mPa s) fluids is difficult, making the study of their capillary-thinning behavior and the measurement of the fluid's extensional viscosity difficult as well. Current techniques require some time to form a liquid bridge from the stretching of a droplet. Rapidly stretching a liquid bridge using these methods can cause its breakup if the viscosity is too low. Stretching more slowly allows the bridge to thin and break up before a suitable bridge geometry can be established to provide reliable and accurate rheological data. Using a pulsed surface acoustic wave to eject a jet from a sessile droplet, a capillary bridge may be formed in about 7.5 ms, about seven times quicker than current methods. With this approach, capillary bridges may be formed from Newtonian and non-Newtonian fluids having much lower viscosities-water, 0.04% by weight solution of high-molecular-weight (7 MDa) polystyrene in dioctyl phthalate and 0.25% fibrinogen solution in demineralized water, for example. Details of the relatively simple system used to achieve these results are provided, as are experimental results indicating deviations from a Newtonian response by the low-viscosity non-Newtonian fluids used in our study.
Bhattacharjee, P. K.; McDonnell, A. G.; Prabhakar, R.; Yeo, L. Y.; Friend, J.
2011-02-01
Forming capillary bridges of low-viscosity (lsim10 mPa s) fluids is difficult, making the study of their capillary-thinning behavior and the measurement of the fluid's extensional viscosity difficult as well. Current techniques require some time to form a liquid bridge from the stretching of a droplet. Rapidly stretching a liquid bridge using these methods can cause its breakup if the viscosity is too low. Stretching more slowly allows the bridge to thin and break up before a suitable bridge geometry can be established to provide reliable and accurate rheological data. Using a pulsed surface acoustic wave to eject a jet from a sessile droplet, a capillary bridge may be formed in about 7.5 ms, about seven times quicker than current methods. With this approach, capillary bridges may be formed from Newtonian and non-Newtonian fluids having much lower viscosities—water, 0.04% by weight solution of high-molecular-weight (7 MDa) polystyrene in dioctyl phthalate and 0.25% fibrinogen solution in demineralized water, for example. Details of the relatively simple system used to achieve these results are provided, as are experimental results indicating deviations from a Newtonian response by the low-viscosity non-Newtonian fluids used in our study.
Extensional Flow of a Polystyrene Boger Fluid Through a 4:1:4 Axisymmetric Contraction/Expansion
Rothstein, Jonathan P.; McKinley, Gareth H.
1999-01-01
The creeping flow of a dilute (0.025 wt%) monodisperse polystyrene/polystyrene Boger fluid through a 4:1:4 axisymmetric contraction/expansion is experimentally observed for a wide range of Deborah numbers. Pressure drop measurements across the orifice plate show a large extra pressure drop that increases monotonically with Deborah number above the value observed for a similar Newtonian fluid at the same flow rate. This enhancement in the dimensionless pressure drop is not associated with the onset of a flow instability, yet it is not predicted by existing steady-state or transient numerical computations with simple dumbbell models. It is conjectured that this extra pressure drop is the result of an additional dissipative contribution to the polymeric stress arising from a stress-conformation hysteresis in the strong non-homogeneous extensional flow near the contraction plane. Such a hysteresis has been independently measured and computed in recent studies of homogeneous transient uniaxial stretching of PS/PS Boger fluids. Flow visualization and velocity field measurements using digital particle image velocimetry (DPIV) show large upstream growth of the corner vortex with increasing Deborah number. At large Deborah numbers, the onset of an elastic instability is observed, first locally as small amplitude fluctuations in the pressure measurements, and then globally as an azimuthal precessing of the upstream corner vortex accompanied by periodic oscillations in the pressure drop across the orifice.
Jansson, A.; Lundberg, B.
2008-09-01
A straight bar element containing piezoelectric members is viewed as a linear system with one electrical and two mechanical ports where it can interact with external electrical and mechanical devices through voltage, current, forces and velocities. A generalized force vector, with one voltage and two forces as elements, is expressed as the product of an impedance matrix and a generalized velocity vector, with one current and two velocities, as elements. Due to symmetry and reciprocity, this matrix is defined by four of its nine elements. Two applications are considered for a piezoelectric bar element (PBE) that constitutes a part of a long elastic or viscoelastic bar, viz. generation and damping of extensional waves in the bar. In the first, the PBE is driven by a given input voltage or by the output voltage from a linear power amplifier. In the second, the PBE supplies an output voltage to an external load. In numerical simulations carried out for a specific laminated PBE, an elastic bar, a serial RL load and a bell-shaped incident wave, the highest fraction of wave energy dissipated was 8.1%. This is much less than the 50% achievable for a harmonic wave under condition of electrical impedance matching.
Poilvet, Jean-Charles; Poujol, Marc; Pitra, Pavel; Van Den Driessche, Jean; Paquette, Jean-Louis
2011-07-01
Dating the magmatism in the Montagne Noire gneiss dome in the southern French Massif Central is a key point for understanding the Late Palaeozoic evolution of this part of the Variscan belt, which is characterised by compressive tectonics during the Carboniferous and extensional tectonics during Stephanian-Permian times. The Montalet granite crops out in the north-western part of the dome and was first considered as an early syntectonic intrusion related to compressive deformation. More recently, it has been dated at 327 Ma and considered as contemporaneous with the diapiric ascent of the Montagne Noire gneiss dome before the Stephanian-Permian extension. We show that in fact, this pluton was emplaced 294 ± 1 Ma ago and is therefore contemporaneous with the Stephanian-Permian extension. This age is consistent with the interpretation of the Montagne Noire Massif as an extensional gneiss dome.
索书田; 钟增球; 游振东
2000-01-01
A detailed tectonic analysis demonstrates that the present ob served regional tectonic configuration of the ultrahigh-pressure metamorphic terrane in the Da bie massif was mainly formed by the extension processes of the post-lndosinian continent-continent oblique collision between the Sino-Korean and V’angtze cratons and ultrahigh-pressure metamorphism (UHPM). The configuration is characterized by a regional tectonic pattern similar to metamorphic core complexes and by the development of multi-layered detachment zones. On the basis of the identification of compressional and extensional fabrics, it is indicated that the exhumation and uplift of ultrahigh-pressure (UHP) metamorphic rocks from the mantle depth to the surface can be divided into at least three different decompression retrogressive metamo rphism and tectonic deformation stages, in which the subhorizontal crustal-scale extensional flow in the middle-lower crust under amphibolite facies conditions is an important geodynamic process in the exhu
Garrett, W E
1996-01-01
with respect to the beneficial effects of warm-up, temperature, and stretching on the mechanical properties of muscle. These benefits potentially reduce the risks of strain injury to the muscle. Fortunately, many of the factors protecting muscle, such as strength, endurance, and flexibility, are also essential for maximum performance. Future studies should delineate the repair and recovery process emphasizing not only the recovery of function, but also the susceptibility to reinjury during the recovery phase.
Angela Maria Gozzo
2009-09-01
Full Text Available Foram avaliadas as viscosidades extensional e em cisalhamento de suspensões acidificadas de amido de amaranto-caseinato de sódio. Sistemas mistos de amido de amaranto-caseinato de sódio acidificados com glucona-delta-lactona (GDL foram estudados por ensaios reológicos em compressão biaxial e cisalhamento. Os efeitos da velocidade de acidificação (lenta e rápida e pH final (neutro e no ponto isoelétrico da caseína foram avaliados considerando as interações entre os biopolímeros e sua consequente influência nos parâmetros reológicos. Todas as amostras apresentaram comportamento pseudoplástico, no entanto, a adição de caseinato de sódio nas suspensões de amido, em pH neutro, promoveu um efeito negativo sobre a viscosidade aparente. Amostras acidificadas apresentaram um aumento na complexidade do sistema devido à formação da rede de amido e caseína, observando que a força necessária para o escoamento foi sempre maior para as amostras contendo concentrações maiores de caseinato. Isso mostra que a agregação e gelificação da proteína promovidas pela acidificação, impediram a microsseparação de fases. Esta rede foi mais forte em sistemas gelificados lentamente, devido à formação de uma rede de proteína mais organizada. Apesar da técnica de compressão biaxial imperfeita ser limitada para avaliação de determinados sistemas, neste estudo, mostrou ser um modo prático e eficiente de se mensurar o comportamento reológico.Extensional and shear viscosity of acidified amaranth starch-sodium caseinate suspensions were evaluated. Mixed systems of amaranth starch-sodium caseinate acidified with glucone-delta-lactone (GDL were studied using rheological measurements under biaxial compression and shear. The effects of the acidification rate (slow and fast and final pH (neutral and isoelectric point of casein were evaluated considering the interactions between biopolymers and their influence on the rheological parameters
索书田; 钟增球; 游振东; 张泽明
2001-01-01
The present-day observable tectonic framework of the ultrahigh-pressure (UHP) and high-pressure (HP) metamorphic belts in the Dabie-Sulu region was dominantly formed by an extensional process, mostly between 200 and 170 Ma, following the Triassic collision between the Sino-Korean and Yangtze cratons. The framework that controls the present spatial distribution of UHP and HP metamorphic rocks in particular displays the typical features of a Cordilleran-type metamorphic core complex, in which at least four regional-scale, shallow-dipping detachment zones are recognized. Each of these detachment zones corresponds to a pressure gap of 0.5 to 2.0 GPa. The detachment zones separate the rocks exposed in the region into several petrotectonic units with different P-T conditions. The geometry and kinematics of both the detachment zones and the petrotectonic units show that the exhumation of UHP and HP metamorphic rocks in the Dabie-Sulu region was achieved, at least in part, by non-coaxial ductile flow in the multi-layered detachment zones, and by coaxial vertical shortening and horizontal stretching in the metamorphic units, under amphibolite- to greenschist-facies conditions, and in an extensional regime. All ductile extensional deformations occurred at depths below 10 to 15 km, i.e. below the brittle/ductile deformation transition.
无
2000-01-01
A detailed tectonic analysis demonstrates that the present observed regional tectonic configuration of the ultrahigh-pressure metamorphic terrane in the Dabie massif was mainly formed by the extension processes of the post-Indosinian continent-continent oblique collision between the Sino-Korean and Yangtze cratons and ultrahigh-pressure metamorphism (UHPM). The configuration is characterized by a regional tectonic pattern similar to metamorphic core complexes and by the development of multi-layered detachment zones. On the basis of the identification of compressional and extensional fabrics, it is indicated that the exhumation and uplift of ultrahigh-pressure (UHP) metamorphic rocks from the mantle depth to the surface can be divided into at least three different decompression retrogressive metamorphism and tectonic deformation stages, in which the subhorizontal crustal-scale extensional flow in the middle-lower crust under amphibolite facies conditions is an important geodynamic process in the exhumation of UHP metamorphic rocks. Moreover, the extensional flow is probably driven by delamination and magmatic underplating of thickened lithospheric mantle following the continental oblique collision.
Gomes, Caroline J S; Martins-Neto, Marcelo A; Ribeiro, Valéria E
2006-06-01
Analogue experiments were carried out to get insights into the processes governing positive inversion during the foreland propagating thrust tectonics in the southern Serra do Espinhaço, a Brasiliano/Panafrican foldthrust belt in southeast Brazil. In particular, model listric half-grabens were inverted by applying contractional displacement to the footwall blocks. We investigated two different inversion conditions in listric half-grabens: (i) extensional and contractional detachments at the same level and (ii) at different positions. The models revealed that the development of a forward-breaking thrust system occurs in the basin synrift deposits, by contractional translation of the extensional footwall block when the extensional and contractional master faults do not coincide. Our experiments show the tectonic imbrication between basement and synrift sequences which characterizes the southern Serra do Espinhaço, and support the location in the eastern mountain range domain of the Espinhaço rift master fault system, which is not exposed at the surface.
A Reconsideration of the Extension Strain Criterion for Fracture and Failure of Rock
Wesseloo, J.; Stacey, T. R.
2016-12-01
The complex behaviours of rocks and rock masses have presented paradoxes to the rock engineer, including the fracturing of seemingly strong rock under low stress conditions, which often occurs near excavation boundaries. The extension strain criterion was presented as a fracture initiation criterion under these conditions (Stacey in Int J Rock Mech Min Sci 18:469-474, 1981). This criterion has been used successfully by some and criticised by others. In this paper, we review the literature on the extension strain criterion and present a case for the correct interpretation of the criterion and the conditions suitable for its use. We argue that the extension strain criterion can also be used to provide an indication of damage level under conditions of relatively low confining stress. We also present an augmentation of the criterion, the ultimate extension strain, which is applicable under extensional loading conditions when σ 2 is similar in magnitude to σ 1.
Receiver function estimated by maximum entropy deconvolution
吴庆举; 田小波; 张乃铃; 李卫平; 曾融生
2003-01-01
Maximum entropy deconvolution is presented to estimate receiver function, with the maximum entropy as the rule to determine auto-correlation and cross-correlation functions. The Toeplitz equation and Levinson algorithm are used to calculate the iterative formula of error-predicting filter, and receiver function is then estimated. During extrapolation, reflective coefficient is always less than 1, which keeps maximum entropy deconvolution stable. The maximum entropy of the data outside window increases the resolution of receiver function. Both synthetic and real seismograms show that maximum entropy deconvolution is an effective method to measure receiver function in time-domain.
Renato P. Almeida
2012-06-01
Full Text Available In Eastern South America, a series of fault-bounded sedimentary basins that crop out from Southern Uruguay to Southeastern Brazil were formed after the main collisional deformation of the Brasiliano Orogeny and record the tectonic events that affected the region from the Middle Ediacaran onwards. We address the problem of discerning the basin-forming tectonics from the later deformational events through paleostress analysis of more than 600 fault-slip data, mainly from the Camaquã Basin (Southern Brazil, sorted by stratigraphic level and cross-cutting relationships of superposed striations, and integrated with available stratigraphic and geochronological data. Our results show that the Camaquã Basin was formed by at least two distinct extensional events, and that rapid paleostress changes took place in the region a few tens of million years after the major collision (c.a. 630 Ma, probably due to the interplay between local active extensional tectonics and the distal effects of the continued amalgamation of plates and terranes at the margins of the still-forming Gondwana Plate. Preliminary paleostress data from the Castro Basin and published data from the Itajaí Basin suggest that these events had a regional nature.No Leste da América do Sul, um conjunto de bacias sedimentares que afloram do sul do Uruguai ao sudeste do Brasil formou-se após os eventos colisionais da Orogenia Brasiliana, registrando os eventos tectônicos que afetaram a região a partir do Mesoediacarano. O problema da distinção entre a tectônica formadora das bacias e os eventos deformacionais posteriores é aqui abordado através da análise de paleotensões de mais de 600 dados de falhas com estrias, obtidos principalmente na Bacia Camaquã (Sul do Brasil, que foram classificados por nível estratigráfico e relações de corte entre estrias sobrepostas, e intergrados a dados estratigráficos e geocronológicos disponíveis. Nossos resultados revelam que a Bacia Camaqu
Ramos-Arias, M. A.; Keppie, J. D.; Ortega-Rivera, A.; Lee, J. W. K.
2008-02-01
earliest cleavage in the Las Minas unit yielded a plateau age of 347 ± 3 Ma and show low temperature ages of ˜ 260 Ma. Post-dating all of these structures and the Patlanoaya Group are NE-plunging, subvertical folds and kink bands. An E-W, vertical normal fault juxtaposes the low-grade rocks against the Anacahuite amphibolite that is cut by megacrystic granite sheets, both of which were deformed by two penetrative fabrics. Amphibole from this unit has yielded a 40Ar/ 39Ar plateau age of 299 ± 6 Ma, which records cooling through ˜ 490 °C and is probably related to a Permo-Carboniferous reheating event during exhumation. The extensional deformation is inferred to have started in the latest Devonian (˜ 360 Ma) during deposition of the basal Patlanoaya Group, lasting through the rapid exhumation of the Piaxtla Suite at ˜ 350-340 Ma synchronous with cleavage development in the Las Minas unit, deposition of the Patlanoaya Group with active fault-related exhumation suggested by Mississippian and Early Permian conglomerates (˜ 340 and 300 Ma, respectively), and continuing at least into the Middle Permian (≡ 260 Ma muscovite ages). The continuity of Mid-Continent Mississippian fauna from the USA to southern Mexico suggests that this extensional deformation occurred on the western margin of Pangea after closure of the Rheic Ocean.
Carbone, Daniele; Aloisi, Marco; Vinciguerra, Sergio; Puglisi, Giuseppe
2014-05-01
During the time interval between the 1991-93 and 2001 main flank eruptions of Mt. Etna, volcanic activity was confined to the summit vents. Ground deformation and tomography studies suggest that this activity was fed by a magma body located beneath the north-west flank of the volcano, at a depth of around 7 km b.s.l.. Conversely, gravity studies indicate that the most important mass redistributions during the same period took place within an elongated volume centered below the southeastern sector of the volcano, at depths of 2-4 km b.s.l.. The phases of gravity decrease during the 1994-2001 period coincide with phases of higher strain release rate. The coupling between gravity and seismic data could reflect changes in the rate of micro-fracturing along the NNW-SSE weakness zone that cuts the SE slope of the volcano. This interpretation allows to explain why the main pressure and mass sources active at Etna during the 1994-2001 period do not coincide. The extensional dynamics of the southeastern flank of Etna may represent a second-order effect, triggered by the pressure source below the western flank and accommodated along the NNW-SSE weakness zone. In order to gain quantitative insight into the relationship between stress, strain and mass changes at Etna during the 1994-2001 period, we use a finite element modeling approach. Relying on recent studies involving stress- and temperature-induced degradation of the mechanical properties of rocks, we hypothesize that the inferred NNW-SSE weakness zone is characterized by an anomalously low Young's modulus (E). Results of our analysis are summarized in the following two points. (i) The presence of the weakness zone creates a distortion of the displacements field induced by the deeper pressure source, locally resulting in a weak extensional regime. This finding supports the hypothesis of a cause-effect relation between deeper pressurization beneath the western flank and shallower extension across the fracture zone beneath
Maximum Power from a Solar Panel
Michael Miller
2010-01-01
Full Text Available Solar energy has become a promising alternative to conventional fossil fuel sources. Solar panels are used to collect solar radiation and convert it into electricity. One of the techniques used to maximize the effectiveness of this energy alternative is to maximize the power output of the solar collector. In this project the maximum power is calculated by determining the voltage and the current of maximum power. These quantities are determined by finding the maximum value for the equation for power using differentiation. After the maximum values are found for each time of day, each individual quantity, voltage of maximum power, current of maximum power, and maximum power is plotted as a function of the time of day.
Morata, D.; Aguirre, L.
2003-12-01
Lower Cretaceous volcanism in the Coastal Range (29°20'-30°S) of Chile is mainly represented by highly porphyritic (20-30% phenocrysts) lavas with unzoned Ca-rich plagioclase (An 57-54Ab 40-42Or 3-4), clinopyroxene (Wo 40En 43Fs 17), magnetite, and minor idiomorphic, altered olivines. Geochemically, these lavas are characterized by a relative homogeneity with high Al 2O 3 and low MgO contents, and classified as high-K to shoshonitic basaltic andesites to andesites generated in an intra-arc extensional setting due to oblique subduction. Their isotopic geochemistry is characterized by highly homogeneous low initial Sr ratios (( 87Sr/ 86Sr) 0˜0.7036) and positive ɛNd values ( ɛNd=+2.9 to +4.7 ( 143Nd/ 144Nd) 0˜0.5127) that are very different from those proposed as representative of 'Andean-type' magmatism. A non-Andean modern setting dominated by subduction associated with intra-arc extension is proposed. On a ( 87Sr/ 86Sr) 0 versus ɛNd diagram, these lavas fit a model mixing curve for which the end members are Pacific MORB and Jurassic plutonic rocks from the Coastal Range. Coeval granitoids from the Coastal Range and lavas from the High Andes plot on the same field. Isotopically depleted mafic magmas could be metasomatized by the subducted sediments, which would increase their LILE content, and then partially contaminated by Jurassic plutonic rocks. The genesis of this magmatism may be related to a global low-spreading rate of 5 cm yr -1 in the southeast Pacific during 125-110 Ma.
Application of the maximum entropy method to profile analysis
Armstrong, N.; Kalceff, W. [University of Technology, Department of Applied Physics, Sydney, NSW (Australia); Cline, J.P. [National Institute of Standards and Technology, Gaithersburg, (United States)
1999-12-01
Full text: A maximum entropy (MaxEnt) method for analysing crystallite size- and strain-induced x-ray profile broadening is presented. This method treats the problems of determining the specimen profile, crystallite size distribution, and strain distribution in a general way by considering them as inverse problems. A common difficulty faced by many experimenters is their inability to determine a well-conditioned solution of the integral equation, which preserves the positivity of the profile or distribution. We show that the MaxEnt method overcomes this problem, while also enabling a priori information, in the form of a model, to be introduced into it. Additionally, we demonstrate that the method is fully quantitative, in that uncertainties in the solution profile or solution distribution can be determined and used in subsequent calculations, including mean particle sizes and rms strain. An outline of the MaxEnt method is presented for the specific problems of determining the specimen profile and crystallite or strain distributions for the correspondingly broadened profiles. This approach offers an alternative to standard methods such as those of Williamson-Hall and Warren-Averbach. An application of the MaxEnt method is demonstrated in the analysis of alumina size-broadened diffraction data (from NIST, Gaithersburg). It is used to determine the specimen profile and column-length distribution of the scattering domains. Finally, these results are compared with the corresponding Williamson-Hall and Warren-Averbach analyses. Copyright (1999) Australian X-ray Analytical Association Inc.
... flexor - aftercare; Hip flexor injury - aftercare; Hip flexor tear - aftercare; Iliopsoas strain - aftercare; Strained iliopsoas muscle - aftercare; Torn iliopsoas muscle - aftercare; Psoas strain - aftercare
The inverse maximum dynamic flow problem
BAGHERIAN; Mehri
2010-01-01
We consider the inverse maximum dynamic flow (IMDF) problem.IMDF problem can be described as: how to change the capacity vector of a dynamic network as little as possible so that a given feasible dynamic flow becomes a maximum dynamic flow.After discussing some characteristics of this problem,it is converted to a constrained minimum dynamic cut problem.Then an efficient algorithm which uses two maximum dynamic flow algorithms is proposed to solve the problem.
Maximum permissible voltage of YBCO coated conductors
Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)
2014-06-15
Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.
Bistacchi, A.; Gatta, D.; Grizzetti, R.; Pennacchioni, G.
2008-12-01
The characterisation of fault rocks from exhumed faults is of paramount importance in fault and earthquake mechanics, since these rocks might provide constraints for models of seismic rupture initiation and propagation. The Trois Ville Fault is a major Oligocene extensional fault of the internal NW Alps, showing a cumulative displacement of c.a. 1 km evidenced by the offset boundary between Austroalpine gneisses (hangingwall) and Piedmont calcschists (footwall). Fault rocks consist of greenschist mylonitic gneiss (from an early stage), green indurated cataclasites, which constitute the 2-10 m thick core zone, and a thin (c.a. 10 cm) but extremely continuous layer of polycyclic pseudotachylytes which mark a strongly localised principal slipping zone. Pseudotachylytes lack distinctive features such as glass, microlites-spherulites, etc., but show a distinctive mineralogy of the melt-derived very fine-grained matrix, which is almost entirely constituted by monoclinic K-feldspar (low sanidine crystallised at ca. 990°C and partly ordered as far as 500- 700°C). This matrix is composed by very small crystals (0.5-5 μm), organised in aggregates and dendritic snowflake-like aggregates which might be explained by sintering or synneusis processes. The high crystallization T implies that pseudotachylytes derive from frictional melting of ultracataclasites (possibly incoherent, hence a fault gouge, at the time of deformation) near the brittle plastic transition (250- 300°C and 8-10 km). Hence, a new diagnostic criterion for frictional melting, based on crystallographic analysis, is introduced in this work. The melt mainly derived from phyllosilicates (muscovite and minor chlorite; Tmelt c.a. 750°C) and evidences of superheating may be envisaged (partial assimilation of albite and quartz; T > c.a. 1300°C). This points to a considerable seismic slip after the onset of frictional melting and to an efficient melting lubrication process in this kind of fault rocks
Generalised maximum entropy and heterogeneous technologies
Oude Lansink, A.G.J.M.
1999-01-01
Generalised maximum entropy methods are used to estimate a dual model of production on panel data of Dutch cash crop farms over the period 1970-1992. The generalised maximum entropy approach allows a coherent system of input demand and output supply equations to be estimated for each farm in the sam
20 CFR 229.48 - Family maximum.
2010-04-01
... month on one person's earnings record is limited. This limited amount is called the family maximum. The family maximum used to adjust the social security overall minimum rate is based on the employee's Overall..., when any of the persons entitled to benefits on the insured individual's compensation would, except...
The maximum rotation of a galactic disc
Bottema, R
1997-01-01
The observed stellar velocity dispersions of galactic discs show that the maximum rotation of a disc is on average 63% of the observed maximum rotation. This criterion can, however, not be applied to small or low surface brightness (LSB) galaxies because such systems show, in general, a continuously
Duality of Maximum Entropy and Minimum Divergence
Shinto Eguchi
2014-06-01
Full Text Available We discuss a special class of generalized divergence measures by the use of generator functions. Any divergence measure in the class is separated into the difference between cross and diagonal entropy. The diagonal entropy measure in the class associates with a model of maximum entropy distributions; the divergence measure leads to statistical estimation via minimization, for arbitrarily giving a statistical model. The dualistic relationship between the maximum entropy model and the minimum divergence estimation is explored in the framework of information geometry. The model of maximum entropy distributions is characterized to be totally geodesic with respect to the linear connection associated with the divergence. A natural extension for the classical theory for the maximum likelihood method under the maximum entropy model in terms of the Boltzmann-Gibbs-Shannon entropy is given. We discuss the duality in detail for Tsallis entropy as a typical example.
Spencer, Jon E.; Reynolds, Stephen J.; Scott, Robert J.; Richard, Stephen M.
2016-12-01
Detailed geologic mapping in the Buckskin, Rawhide, and Artillery Mountains in western Arizona identified numerous folds in Oligocene-Miocene strata above the Buckskin-Rawhide extensional detachment fault. The folds are above or adjacent to the Harcuvar metamorphic core complex, which was uplifted and exposed by top-northeast normal faulting and penetrative shearing at 27-9 Ma. Strata deposited during extension were folded, and the folds are truncated by the detachment fault, demonstrating that folding occurred during the period of extensional faulting. Fold axes are approximately perpendicular to regional extension direction. In two of the four areas of folding described here, alluvial-fan deposits derived partially from lower plate mylonitic rocks are the stratigraphically highest folded strata. Folding could have occurred above low-angle normal faults with curved or ramp-flat geometries, but fold abundance, large size, high degree of closure, and steep northeastward dips of the northeast limbs of anticlines lead us to consider the possibility that at least some folds reflect local shortening in the same direction as regional extension. Application of critical-taper theory to an extensional wedge with very low basal friction indicates that wedge shortening would be expected if the wedge developed a sufficient surface slope that was downhill away from the wedge tip. Such a slope could have developed late during extension either because core-complex uplift tilted the wedge away from the core complex or because alluvial fans shed off the core complex produced such a slope. In either case, wedge shortening would promote core-complex denudation.
Garibaldi, Nicolás; Tikoff, Basil; Hernández, Walter
2016-12-01
Dominantly westward movement of the El Salvador forearc at rates of 11 mm/yr is accommodated by a series of E-W to WNW oriented, dextral, strike-slip fault zones herein referred to as the El Salvador Fault System (ESFS). The geometry of the ESFS defines a series of extensional step-overs. Along the arc, basaltic volcanism in the stepovers is associated with NNW-oriented normal faults, whereas rhyolitic volcanism is associated with strike-slip fault zones of the ESFS. On the ESFS, the San Salvador Extensional Stepover (SSES) is bound to the south by the San Vicente fault zone, where the rhyolitic Ilopango caldera is located. In the SSES, tephras from Ilopango -the Tierra Blanca (TB) sequence- track long-term elongation. Older TB units (TB5-8) contain abundant normal faults; lying unconformably above these older TB units, younger TB members (TBJ, TB2-4) are generally unfaulted. Analyses of faults in TB5-8 indicate NE- to ENE-oriented elongation in the SSES. Deformation occurred between deposition of the TB4 and TB5 units, during quiescence of the Ilopango eruptive center. Using this temporal constraint, minimum elongation rates of 3.50 × 10- 15 s- 1, 2.06 × 10- 14 s- 1 and 4.42 × 10- 14 s- 1 were calculated for three traverses. From regional geodetic data and fault kinematics throughout El Salvador, we interpret the SSES as part of a series of pull-apart structures along the arc axis. The calculated paleostress orientations are consistent with a pull-apart geometry resulting from forearc movement. The extensional deformation occurs during a 50 k.y. lull in rhyolitic activity, suggesting an interplay between magmatism and deformation within the arc. During significant rhyolitic volcanic activity, only minor elongation is observed in the SSES, despite ongoing translation of the Salvadoran forearc. We speculate that rhyolitic magmatism along upper crustal faults may facilitate strike-slip movement on the ESFS, rather than distributing deformation throughout the
Adinolfi, Guido Maria; Lavecchia, Giusy; De Matteis, Raffaella; Nardis Rita, De; Francesco, Brozzetti; Federica, Ferrarini; Zollo, Aldo
2015-04-01
On April 6, 2009 (at 01:32 UTC) a Mw 6.3 earthquake hit the town of L'Aquila (central Italy) and surrounding villages causing fatalities and severe damage in the area. After few days, a nearly 40-km-long extensional fault system was activated generating both northward and southward seismicity migration along the NW-SE trending sector of central Apennines. During the intense aftershocks sequence, different sesmogenic sources with a distinct geometry, size and the degree of involvement were reactivated. Among the relevant aftershocks with Mw 5.0 to 5.5, the largest one occurred on April 7 (at 17:47 UTC), 9 km SE-ward of the mainshock involving a source seated at much greater depths (~14 km). Despite the enormous number of studies of the 2009 L'Aquila earthquake, mainly focused on the various geological and seismological aspects of the main Paganica source, the April 7 strongest aftershock (Mw 5.5) has not yet been deeply investigated. Consistent geometric and kinematic correlations between the geological and seismological data about this seismogenic source are missing. There are still open questions concerning its unresolved geometry and the unknown style of the central Apennines structure activated at greater depths during the 2009 L'Aquila seismic sequence. Furthermore, some authors (Lavecchia et al., 2012) have supposed that the April 7, 2009 aftershock (Mw 5.5) occurred onto an high dip segment (~50°) of an east-dipping extensional basal detachment with a potential surface expression outcropping in the area of the eastern Sabina-Simbruini Mts. In this work we propose a seismological analysis of the April 7, 2009 aftershock (Mw 5.5) rupture process. In order to define the unresolved source geometry, we computed the focal mechanism through the time domain, moment tensor full waveform inversion (Dreger and Helmberger, 1993). Also, we estimated the apparent source time functions (ASTFs) by deconvolution of the impulse response of the medium from the recorded data
Persistence of strain in motor-filament assemblies
Gopinath, Arvind; Mahadevan, L
2015-01-01
Crosslinked semi-flexible and flexible filaments that are actively deformed by molecular motors occur in various natural settings, such as the ordered eukaryotic flagellum, and the disordered cytoskeleton. The deformation of these composite systems is driven by active motor forces and resisted by passive filament elasticity, and structural constraints due to permanent cross-links. Using a mean field theory for a one-dimensional ordered system, we show that the combination of motor activity and finite filament extensibility yields a characteristic persistence length scale over which active strain decays. This decay length is set by the ability of motors to respond to combination of the weak extensional elasticity, passive shear resistance and the viscoelastic properties of the motor assembly, and generalizes the notion of persistence in purely thermal filaments to active systems.
A dual method for maximum entropy restoration
Smith, C. B.
1979-01-01
A simple iterative dual algorithm for maximum entropy image restoration is presented. The dual algorithm involves fewer parameters than conventional minimization in the image space. Minicomputer test results for Fourier synthesis with inadequate phantom data are given.
Maximum Throughput in Multiple-Antenna Systems
Zamani, Mahdi
2012-01-01
The point-to-point multiple-antenna channel is investigated in uncorrelated block fading environment with Rayleigh distribution. The maximum throughput and maximum expected-rate of this channel are derived under the assumption that the transmitter is oblivious to the channel state information (CSI), however, the receiver has perfect CSI. First, we prove that in multiple-input single-output (MISO) channels, the optimum transmission strategy maximizing the throughput is to use all available antennas and perform equal power allocation with uncorrelated signals. Furthermore, to increase the expected-rate, multi-layer coding is applied. Analogously, we establish that sending uncorrelated signals and performing equal power allocation across all available antennas at each layer is optimum. A closed form expression for the maximum continuous-layer expected-rate of MISO channels is also obtained. Moreover, we investigate multiple-input multiple-output (MIMO) channels, and formulate the maximum throughput in the asympt...
Photoemission spectromicroscopy with MAXIMUM at Wisconsin
Ng, W.; Ray-Chaudhuri, A.K.; Cole, R.K.; Wallace, J.; Crossley, S.; Crossley, D.; Chen, G.; Green, M.; Guo, J.; Hansen, R.W.C.; Cerrina, F.; Margaritondo, G. (Dept. of Electrical Engineering, Dept. of Physics and Synchrotron Radiation Center, Univ. of Wisconsin, Madison (USA)); Underwood, J.H.; Korthright, J.; Perera, R.C.C. (Center for X-ray Optics, Accelerator and Fusion Research Div., Lawrence Berkeley Lab., CA (USA))
1990-06-01
We describe the development of the scanning photoemission spectromicroscope MAXIMUM at the Wisoncsin Synchrotron Radiation Center, which uses radiation from a 30-period undulator. The article includes a discussion of the first tests after the initial commissioning. (orig.).
Maximum-likelihood method in quantum estimation
Paris, M G A; Sacchi, M F
2001-01-01
The maximum-likelihood method for quantum estimation is reviewed and applied to the reconstruction of density matrix of spin and radiation as well as to the determination of several parameters of interest in quantum optics.
3D Geodynamic Modelling Reveals Stress and Strain Partitioning within Continental Rifting
Rey, P. F.; Mondy, L. S.; Duclaux, G.; Moresi, L. N.
2014-12-01
The relative movement between two divergent rigid plates on a sphere can be described using a Euler pole and an angular velocity. On Earth, this typically results in extensional velocities increasing linearly as a function of the distance from the pole (for example in the South Atlantic, North Atlantic, Woodlark Basin, Red Sea Basin, etc.). This property has strong implications for continental rifting and the formation of passive margins, given the role that extensional velocity plays on both rift style (wide or narrow), fault pattern, subsidence histories, and magmatism. Until now, this scissor-style opening has been approached via suites of 2D numerical models of contrasting extensional velocities, complimenting field geology and geophysics. New advances in numerical modelling tools and computational hardware have enabled us to investigate the geodynamics of this problem in a 3D self-consistent high-resolution context. Using Underworld at a grid resolution of 2 km over a domain of 500 km x 500 km x 180 km, we have explored the role of the velocity gradient on the strain pattern, style of rifting, and decompression melting, along the margin. We find that the three dimensionality of this problem is important. The rise of the asthenosphere is enhanced in 2D models compared to 3D numerical solutions, due to the limited volume of material available in 2D. This leads to oceanisation occurring significantly sooner in 2D models. The 3D model shows that there is a significant time and space dependent flows parallel to the rift-axis. A similar picture emerges from the stress field, showing time and space partitioning, including regions of compression separating areas dominated by extension. The strain pattern shows strong zonation along the rift axis, with increasingly localised deformation with extension velocity and though time.
The maximum entropy technique. System's statistical description
Belashev, B Z
2002-01-01
The maximum entropy technique (MENT) is applied for searching the distribution functions of physical values. MENT takes into consideration the demand of maximum entropy, the characteristics of the system and the connection conditions, naturally. It is allowed to apply MENT for statistical description of closed and open systems. The examples in which MENT had been used for the description of the equilibrium and nonequilibrium states and the states far from the thermodynamical equilibrium are considered
19 CFR 114.23 - Maximum period.
2010-04-01
... 19 Customs Duties 1 2010-04-01 2010-04-01 false Maximum period. 114.23 Section 114.23 Customs... CARNETS Processing of Carnets § 114.23 Maximum period. (a) A.T.A. carnet. No A.T.A. carnet with a period of validity exceeding 1 year from date of issue shall be accepted. This period of validity cannot be...
Maximum-Likelihood Detection Of Noncoherent CPM
Divsalar, Dariush; Simon, Marvin K.
1993-01-01
Simplified detectors proposed for use in maximum-likelihood-sequence detection of symbols in alphabet of size M transmitted by uncoded, full-response continuous phase modulation over radio channel with additive white Gaussian noise. Structures of receivers derived from particular interpretation of maximum-likelihood metrics. Receivers include front ends, structures of which depends only on M, analogous to those in receivers of coherent CPM. Parts of receivers following front ends have structures, complexity of which would depend on N.
Creep measurements confirm steady flow after stress maximum in extension of branched polymer melts
Javier Alvarez, Nicolas; Román Marín, José Manuel; Huang, Qian;
2013-01-01
We provide conclusive evidence of nonmonotonic mechanical behavior in the extension of long-chain branched polymer melts. While nonmonotonic behavior is known to occur for solids, for the case of polymeric melts, this phenomenon is in direct contrast with current theoretical models. We rule out...... the possibility of the overshoot being an experimental artifact by confirming the existence of steady flow after a maximum in the ratio of stress to strain rate versus strain under both constant stress and constant strain-rate kinematics. This observation indicates the omission of important physics from current...
Soula, Jean-Claude; Debat, Pierre; Brusset, Stéphane; Bessière, Gilbert; Christophoul, Frédéric; Déramond, Joachim
2001-11-01
The Montagne Noire, which is situated at the toe of the orogenic wedge of the French Massif Central South European Variscides, appears to be a well-suited area for studying the origin and evolution of middle to upper crustal domes adjacent to foreland basins. The data reported in the present paper show that the Montagne Noire dome is a particular type of basement-involved frontal culmination in an orogenic wedge and foreland basin system. This frontal culmination is characterized by a syn-contractional HT decompression recorded by clockwise PTt paths and widespread strata overturning in thrust and fold structures, which controlled the sedimentation in the adjacent foreland basin. These unusual characteristics are interpreted to be a result of the succession of thrusting, diapirism and extensional collapse. Antiformal stacking of syn-metamorphic thrust sheets controlled the first stages of the foreland basin development. Diapirism was essentially responsible for the HT decompression and widespread strata overturning. Extensional doming was a result of late- to post-metamorphic collapse acting on the pre-existing high-amplitude dome. Diapirism and associated isothermal decompression metamorphism, which constitute the essential difference between the Montagne Noire and 'ordinary' frontal ridges in orogenic wedges, were probably enhanced by a local partial melting of the upper to middle crust. It is suggested that the occurrence of these phenomena in front of an orogenic wedge was related to local over-thickening due to the superposition of an upper crustal antiformal stack on top of a lower crustal ramp anticline.
Ruleman, Chester A.; Larsen, Mort; Stickney, Michael C.
2014-01-01
The catastrophic Hebgen Lake earthquake of 18 August 1959 (MW 7.3) led many geoscientists to develop new methods to better understand active tectonics in extensional tectonic regimes that address seismic hazards. The Madison Range fault system and adjacent Hebgen Lake–Red Canyon fault system provide an intermountain active tectonic analog for regional analyses of extensional crustal deformation. The Madison Range fault system comprises fault zones (~100 km in length) that have multiple salients and embayments marked by preexisting structures exposed in the footwall. Quaternary tectonic activity rates differ along the length of the fault system, with less displacement to the north. Within the Hebgen Lake basin, the 1959 earthquake is the latest slip event in the Hebgen Lake–Red Canyon fault system and southern Madison Range fault system. Geomorphic and paleoseismic investigations indicate previous faulting events on both fault systems. Surficial geologic mapping and historic seismicity support a coseismic structural linkage between the Madison Range and Hebgen Lake–Red Canyon fault systems. On this trip, we will look at Quaternary surface ruptures that characterize prehistoric earthquake magnitudes. The one-day field trip begins and ends in Bozeman, and includes an overview of the active tectonics within the Madison Valley and Hebgen Lake basin, southwestern Montana. We will also review geologic evidence, which includes new geologic maps and geomorphic analyses that demonstrate preexisting structural controls on surface rupture patterns along the Madison Range and Hebgen Lake–Red Canyon fault systems.
Chono, S.; Tsuji, T. [Kochi Institute of Technology, Kochi (Japan)
1999-11-25
The Doi equations have been directly computed for shear and extensional flow without closure approximations. An extension is imposed on the shear flow plane. It is well-known that for simple shear flow there are three orientation regimes, depending on the magnitude of shear rate; rotational (tumbling), oscillatory (wagging), and stationary (aligning) orientation behaviors. When we add an extension to simple shear flow, the time period of tumbling is increased, while the order parameter in the regime is almost unchanged. In the wagging regime, however, both the time period and the order parameter are increased. Transitions from the tumbling and wagging regimes to the aligning regime are induced when more than a certain magnitude of extension is imposed on a system. An extension has also an effect to make the first normal stress difference positive. Furthermore, motion of individual molecules has been analyzed by integrating the Langevin equation. It is found that the aligning state in shear and extensional flow is due to an approximately stationary behavior of individual molecules, while the aligning state in simple shear flow is an apparently stationary behavior of a group of many rotational molecules. (author)
SEXUAL DIMORPHISM OF MAXIMUM FEMORAL LENGTH
Pandya A M
2011-04-01
Full Text Available Sexual identification from the skeletal parts has medico legal and anthropological importance. Present study aims to obtain values of maximum femoral length and to evaluate its possible usefulness in determining correct sexual identification. Study sample consisted of 184 dry, normal, adult, human femora (136 male & 48 female from skeletal collections of Anatomy department, M. P. Shah Medical College, Jamnagar, Gujarat. Maximum length of femur was considered as maximum vertical distance between upper end of head of femur and the lowest point on femoral condyle, measured with the osteometric board. Mean Values obtained were, 451.81 and 417.48 for right male and female, and 453.35 and 420.44 for left male and female respectively. Higher value in male was statistically highly significant (P< 0.001 on both sides. Demarking point (D.P. analysis of the data showed that right femora with maximum length more than 476.70 were definitely male and less than 379.99 were definitely female; while for left bones, femora with maximum length more than 484.49 were definitely male and less than 385.73 were definitely female. Maximum length identified 13.43% of right male femora, 4.35% of right female femora, 7.25% of left male femora and 8% of left female femora. [National J of Med Res 2011; 1(2.000: 67-70
Tranos, Markos
2013-04-01
The new graphical TR method uses the slip preference (SP) of the faults to separate heterogeneous fault-slip data. This SP is described in detail and several examples of the application of the TR method are presented. For this purpose, synthetic fault-slip data driven by various extensional and compressional stress regimes whose greatest principal stress axis (σ1) or least principal stress axis (σ3) always remains in vertical or horizontal position respectively as in Andersonian stress states have been considered. Their SP is given through a simple graphical manner and the aid of the Win-Tensor stress inversion software. The extensional stress regimes that have been examined are the radial extension (RE), radial-pure extension (RE-PE), pure extension (PE), pure extension-transtension (PE-TRN) and transtension (TRN), whereas the compressional stress regimes are the radial compression (RC), radial-pure compression (RC-PC), pure compression (PC), pure compression-transpression (PC-TRP) and transpression (TRP). A necessary condition for the TR method that is the faults dipping towards the certain horizontal principal stress axis of the driving stress regime are dip-slip faults, either normal or reverse ones, is satisfied for all extensional and compressional stress regimes respectively. The trend of the horizontal least or greatest principal stress axis of the driving extensional or compressional stress regime respectively can be directly defined by the trend of the T-axes of the normal faults or the P-axes of the reverse faults respectively. Taking into account a coefficient of friction no smaller than 0.6, the reactivated extensional faults in the crust dip at angles higher than about 40°, and the increase of the stress ratio and/or the fault dip angle results in the increase of the slip deviation from the normal activation. In turn, in the compressional stress regimes, the dip angle and SP of the activated faults suggest the distinction of the compressional
Strain mapping near a triple junction in strained Ni-based alloy using EBSD and biaxial nanogauges
Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Lacroute, Y.; Markey, L.; Salazar, M.; Vignal, V. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France)
2011-05-15
Research highlights: > Surface strains measured using nanogauge were compared to the texture obtained by EBSD. > Statistics of the principal strain discern the grains according to the Schmid factor. > Strain hotspots were localized near a triple junction of alloy 600 under tensile loading. > Asymetrical profile of the GB strains is a criterion for surface cracking initiation. - Abstract: A key element for analyzing the crack initiation in strained polycrystalline alloys is the local quantification of the surface strain distribution according to the grain texture. Using electron backscattered diffraction, the local microstructure was determined to both localize a triple junction and deduce the local Schmid factors. Kernel average misorientation (KAM) was also used to map the areas of defect concentration. The maximum principal strain and the in-plane shear strain were quantified using the biaxial nanogauge. Distortions of the array of nanodots used as spot markers were analyzed near the triple junction. The crystallographic orientation and the surface strain were then investigated both statistically for each grain and locally at the grain boundaries. The superimposition of microstructure and strain maps allows the high strain gradient (reaching 3-fold the applied strain) to be localized at preferential grain boundaries near the triple junction. The Schmid factors and the KAM were compared to the maximum principal strain and the in-plane shear strain respectively. The polycrystalline deformation was attributable first to the rotation of some grains, followed by the elongation of all grains along their preferential activated slip systems.
Schmidt, Marvin; Schütze, Andreas; Seelecke, Stefan
2016-06-01
This paper discusses the influence of material strain and strain rate on efficiency and temperature span of elastocaloric cooling processes. The elastocaloric material, a newly developed quaternary Ni-Ti-Cu-V alloy, is characterized at different maximum strains and strain rates. The experiments are performed with a specially designed test setup, which enables the measurement of mechanical and thermal process parameters. The material efficiency is compared to the efficiency of the Carnot process at equivalent thermal operation conditions. This method allows for a direct comparison of the investigated material with other caloric materials.
Marvin Schmidt
2016-06-01
Full Text Available This paper discusses the influence of material strain and strain rate on efficiency and temperature span of elastocaloric cooling processes. The elastocaloric material, a newly developed quaternary Ni-Ti-Cu-V alloy, is characterized at different maximum strains and strain rates. The experiments are performed with a specially designed test setup, which enables the measurement of mechanical and thermal process parameters. The material efficiency is compared to the efficiency of the Carnot process at equivalent thermal operation conditions. This method allows for a direct comparison of the investigated material with other caloric materials.
Residual strain change resulting from stress corrosion in Carrara marble
Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael
2016-04-01
greater relaxation of extensional strains during the preparatory test, leading to a subsequent increase in compression when the samples were returned to the neutral position prior to our measurement. Thin sections of the notch area help confirm these observations, as a narrow but continuous fracture following grain boundaries is evident in M4 and M2. M5 shows a buildup of extensional strains in the notch tip area due to low loading, though no cracking is evident. These results provide exceptional insight into the physics of fracture propagation under typical real-world conditions. We observe notably different mechanical inter- and intragranular responses to long-term static low loading under either wet or dry conditions, a result which contributes significantly to our ability to evaluate the potential impact of changes in (for example) rainfall distribution, chemistry, and meltwater production on tensile fracture propagation and alpine rock slope stability.
Geobacteraceae strains and methods
Lovley, Derek R.; Nevin, Kelly P.; Yi, Hana
2015-07-07
Embodiments of the present invention provide a method of producing genetically modified strains of electricigenic microbes that are specifically adapted for the production of electrical current in microbial fuel cells, as well as strains produced by such methods and fuel cells using such strains. In preferred embodiments, the present invention provides genetically modified strains of Geobacter sulfurreducens and methods of using such strains.
The maximum rotation of a galactic disc
Bottema, R
1997-01-01
The observed stellar velocity dispersions of galactic discs show that the maximum rotation of a disc is on average 63% of the observed maximum rotation. This criterion can, however, not be applied to small or low surface brightness (LSB) galaxies because such systems show, in general, a continuously rising rotation curve until the outermost measured radial position. That is why a general relation has been derived, giving the maximum rotation for a disc depending on the luminosity, surface brightness, and colour of the disc. As a physical basis of this relation serves an adopted fixed mass-to-light ratio as a function of colour. That functionality is consistent with results from population synthesis models and its absolute value is determined from the observed stellar velocity dispersions. The derived maximum disc rotation is compared with a number of observed maximum rotations, clearly demonstrating the need for appreciable amounts of dark matter in the disc region and even more so for LSB galaxies. Matters h...
Maximum permissible voltage of YBCO coated conductors
Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z.; Hong, Z.; Wang, D.; Zhou, H.; Shen, X.; Shen, C.
2014-06-01
Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (Ic) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the Ic degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.
Computing Rooted and Unrooted Maximum Consistent Supertrees
van Iersel, Leo
2009-01-01
A chief problem in phylogenetics and database theory is the computation of a maximum consistent tree from a set of rooted or unrooted trees. A standard input are triplets, rooted binary trees on three leaves, or quartets, unrooted binary trees on four leaves. We give exact algorithms constructing rooted and unrooted maximum consistent supertrees in time O(2^n n^5 m^2 log(m)) for a set of m triplets (quartets), each one distinctly leaf-labeled by some subset of n labels. The algorithms extend to weighted triplets (quartets). We further present fast exact algorithms for constructing rooted and unrooted maximum consistent trees in polynomial space. Finally, for a set T of m rooted or unrooted trees with maximum degree D and distinctly leaf-labeled by some subset of a set L of n labels, we compute, in O(2^{mD} n^m m^5 n^6 log(m)) time, a tree distinctly leaf-labeled by a maximum-size subset X of L that all trees in T, when restricted to X, are consistent with.
Maximum magnitude earthquakes induced by fluid injection
McGarr, Arthur F.
2014-01-01
Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.
Maximum magnitude earthquakes induced by fluid injection
McGarr, A.
2014-02-01
Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.
... wrestling put people at risk for strains. Gymnastics, tennis, rowing, golf, and other sports that require extensive gripping can increase the risk of hand and forearm strains. Elbow strains sometimes occur in people who participate in ...
Treatment - muscle strain ... Question: How do you treat a muscle strain ? Answer: Rest the strained muscle and apply ice for the first few days after the injury. Anti-inflammatory medicines or acetaminophen ( ...
A muscle strain is the stretching or tearing of muscle fibers. A muscle strain can be caused by sports, exercise, a ... something that is too heavy. Symptoms of a muscle strain include pain, tightness, swelling, tenderness, and the ...
Influences of misfit strains on liquid phase heteroepitaxial growth
Lu, Yanli; Peng, Yingying; Yu, Genggeng; Chen, Zheng
2017-10-01
Influences of misfit strains with different signs on liquid phase heteroepitaxial growth are studied by binary phase field crystal model. It is amazing to find that double islands are formed because of lateral and vertical separation. The morphological evolution of epitaxial layer depends on signs of misfit strains. The maximum atomic layer thickness of double islands under negative misfit strain is larger than that of under positive misfit strain at the same evolutional time, and size differences between light and dark islands is much smaller under negative misfit strain than that of under positive misfit strain. In addition, concentration field and density field approximately have similar variational law along x direction under the same misfit strain but show opposite variational trend under misfit strains with different signs. Generally, free energy of epitaxial growth systems keeps similar variational trend under misfit strains with different signs.
Maximum Multiflow in Wireless Network Coding
Zhou, Jin-Yi; Jiang, Yong; Zheng, Hai-Tao
2012-01-01
In a multihop wireless network, wireless interference is crucial to the maximum multiflow (MMF) problem, which studies the maximum throughput between multiple pairs of sources and sinks. In this paper, we observe that network coding could help to decrease the impacts of wireless interference, and propose a framework to study the MMF problem for multihop wireless networks with network coding. Firstly, a network model is set up to describe the new conflict relations modified by network coding. Then, we formulate a linear programming problem to compute the maximum throughput and show its superiority over one in networks without coding. Finally, the MMF problem in wireless network coding is shown to be NP-hard and a polynomial approximation algorithm is proposed.
The influence of climatically-driven surface loading variations on continental strain and seismicity
Craig, Tim; Calais, Eric; Fleitout, Luce; Bollinger, Laurent; Scotti, Oona
2016-04-01
In slowly deforming regions of plate interiors, secondary sources of stress and strain can result in transient deformation rates comparable to, or greater than, the background tectonic rates. Highly variable in space and time, these transients have the potential to influence the spatio-temporal distribution of seismicity, interfering with any background tectonic effects to either promote or inhibit the failure of pre-existing faults, and potentially leading to a clustered, or 'pulse-like', seismic history. Here, we investigate the ways in which the large-scale deformation field resulting from climatically-controlled changes in surface ice mass over the Pleistocene and Holocene may have influenced not only the seismicity of glaciated regions, but also the wider seismicity around the ice periphery. We first use a set of geodynamic models to demonstrate that a major pulse of seismic activity occurring in Fennoscandia, coincident with the time of end-glaciation, occurred in a setting where the contemporaneous horizontal strain-rate resulting from the changing ice mass, was extensional - opposite to the reverse sense of coseismic displacement accommodated on these faults. Therefore, faulting did not release extensional elastic strain that was building up at the time of failure, but compressional elastic strain that had accumulated in the lithosphere on timescales longer than the glacial cycle, illustrating the potential for a non-tectonic trigger to tap in to the background tectonic stress-state. We then move on to investigate the more distal influence that changing ice (and ocean) volumes may have had on the evolving strain field across intraplate Europe, how this is reflected in the seismicity across intraplate Europe, and what impact this might have on the paleoseismic record.
The Wiener maximum quadratic assignment problem
Cela, Eranda; Woeginger, Gerhard J
2011-01-01
We investigate a special case of the maximum quadratic assignment problem where one matrix is a product matrix and the other matrix is the distance matrix of a one-dimensional point set. We show that this special case, which we call the Wiener maximum quadratic assignment problem, is NP-hard in the ordinary sense and solvable in pseudo-polynomial time. Our approach also yields a polynomial time solution for the following problem from chemical graph theory: Find a tree that maximizes the Wiener index among all trees with a prescribed degree sequence. This settles an open problem from the literature.
Maximum confidence measurements via probabilistic quantum cloning
Zhang Wen-Hai; Yu Long-Bao; Cao Zhuo-Liang; Ye Liu
2013-01-01
Probabilistic quantum cloning (PQC) cannot copy a set of linearly dependent quantum states.In this paper,we show that if incorrect copies are allowed to be produced,linearly dependent quantum states may also be cloned by the PQC.By exploiting this kind of PQC to clone a special set of three linearly dependent quantum states,we derive the upper bound of the maximum confidence measure of a set.An explicit transformation of the maximum confidence measure is presented.
Maximum floodflows in the conterminous United States
Crippen, John R.; Bue, Conrad D.
1977-01-01
Peak floodflows from thousands of observation sites within the conterminous United States were studied to provide a guide for estimating potential maximum floodflows. Data were selected from 883 sites with drainage areas of less than 10,000 square miles (25,900 square kilometers) and were grouped into regional sets. Outstanding floods for each region were plotted on graphs, and envelope curves were computed that offer reasonable limits for estimates of maximum floods. The curves indicate that floods may occur that are two to three times greater than those known for most streams.
Revealing the Maximum Strength in Nanotwinned Copper
Lu, L.; Chen, X.; Huang, Xiaoxu
2009-01-01
The strength of polycrystalline materials increases with decreasing grain size. Below a critical size, smaller grains might lead to softening, as suggested by atomistic simulations. The strongest size should arise at a transition in deformation mechanism from lattice dislocation activities to grain...... boundary–related processes. We investigated the maximum strength of nanotwinned copper samples with different twin thicknesses. We found that the strength increases with decreasing twin thickness, reaching a maximum at 15 nanometers, followed by a softening at smaller values that is accompanied by enhanced...
The Maximum Resource Bin Packing Problem
Boyar, J.; Epstein, L.; Favrholdt, L.M.
2006-01-01
Usually, for bin packing problems, we try to minimize the number of bins used or in the case of the dual bin packing problem, maximize the number or total size of accepted items. This paper presents results for the opposite problems, where we would like to maximize the number of bins used...... algorithms, First-Fit-Increasing and First-Fit-Decreasing for the maximum resource variant of classical bin packing. For the on-line variant, we define maximum resource variants of classical and dual bin packing. For dual bin packing, no on-line algorithm is competitive. For classical bin packing, we find...
Maximum entropy analysis of EGRET data
Pohl, M.; Strong, A.W.
1997-01-01
EGRET data are usually analysed on the basis of the Maximum-Likelihood method \\cite{ma96} in a search for point sources in excess to a model for the background radiation (e.g. \\cite{hu97}). This method depends strongly on the quality of the background model, and thus may have high systematic unce...... uncertainties in region of strong and uncertain background like the Galactic Center region. Here we show images of such regions obtained by the quantified Maximum-Entropy method. We also discuss a possible further use of MEM in the analysis of problematic regions of the sky....
Revealing the Maximum Strength in Nanotwinned Copper
Lu, L.; Chen, X.; Huang, Xiaoxu
2009-01-01
The strength of polycrystalline materials increases with decreasing grain size. Below a critical size, smaller grains might lead to softening, as suggested by atomistic simulations. The strongest size should arise at a transition in deformation mechanism from lattice dislocation activities to grain...... boundary–related processes. We investigated the maximum strength of nanotwinned copper samples with different twin thicknesses. We found that the strength increases with decreasing twin thickness, reaching a maximum at 15 nanometers, followed by a softening at smaller values that is accompanied by enhanced...
Maximum phytoplankton concentrations in the sea
Jackson, G.A.; Kiørboe, Thomas
2008-01-01
A simplification of plankton dynamics using coagulation theory provides predictions of the maximum algal concentration sustainable in aquatic systems. These predictions have previously been tested successfully against results from iron fertilization experiments. We extend the test to data collected...... in the North Atlantic as part of the Bermuda Atlantic Time Series program as well as data collected off Southern California as part of the Southern California Bight Study program. The observed maximum particulate organic carbon and volumetric particle concentrations are consistent with the predictions...
Maximum-Entropy Meshfree Method for Compressible and Near-Incompressible Elasticity
Ortiz, A; Puso, M A; Sukumar, N
2009-09-04
Numerical integration errors and volumetric locking in the near-incompressible limit are two outstanding issues in Galerkin-based meshfree computations. In this paper, we present a modified Gaussian integration scheme on background cells for meshfree methods that alleviates errors in numerical integration and ensures patch test satisfaction to machine precision. Secondly, a locking-free small-strain elasticity formulation for meshfree methods is proposed, which draws on developments in assumed strain methods and nodal integration techniques. In this study, maximum-entropy basis functions are used; however, the generality of our approach permits the use of any meshfree approximation. Various benchmark problems in two-dimensional compressible and near-incompressible small strain elasticity are presented to demonstrate the accuracy and optimal convergence in the energy norm of the maximum-entropy meshfree formulation.
Bucci, Francesco; Mirabella, Francesco; Santangelo, Michele; Cardinali, Mauro; Guzzetti, Fausto
2016-04-01
Active extensional basins are important since their sedimentary infills and bounding tectonic structures provide: i) sinks with preservation potential for sedimentary and fossil records of past changes in climate and sediment/water supply, ii) information on the growth, activity, decay and death of normal faults, iii) vast economic reserves of hydrocarbons, water and minerals. Unfortunately, quaternary extensional basins, especially if located in humid and temperate climate environments, are often characterized by extensively cultivated areas, homogeneous terrains and quite flat morphologies. Furthermore, they commonly host human settlements, together with roads, economic and industrial infrastructures, with a consequent limited availability of good outcrops. Such a limitation can (often severely) hamper an adequate mapping of the sedimentary infill. Therefore alternative methodological approaches (such as aerial photographs interpretation, API) are needed to integrate heterogeneous and incomplete datasets. This contribution presents an updated photo-geological map of a Quaternary extensional basin in Central Italy, the Montefalco Basin. This basin developed in a continental environment characterized by clayey-sandy lacustrine and fluvial sequences (late Pliocene - early Pleistocene) underlying more recent coarse grained deposits related to alluvial fan environment (early-to-late Pleistocene) and younger palustrine deposits (late Pleistocene). Since the late Pleistocene, regional uplift and local tectonics led to the end of deposition in the Montefalco basin, which experienced a diffuse incision and the modification of the drainage network, in response to the W-to-E migration of active faulting and tectonic subsidence. The new photo-geological map represents an important improvement compared to the existing data, since it provides unprecedented and spatially distributed information on the geometry of the continental deposits and on the tectonic structures affecting
Beard, L.; Umhoefer, P. J.; Martin, K. L.; Blythe, N.
2007-12-01
New studies of selected basins in the Miocene extensional belt of the northern Lake Mead domain suggest a new model for the early extensional history of the region (lower Horse Spring Formation and correlative strata). Critical data are from (i) Longwell Ridges area west of Overton Arm and within the Lake Mead fault system, (ii) Salt Spring Wash basin in the hanging wall of the South Virgin-White Hills detachment (SVWHD) fault, and (iii) previously studied subbasins of the south Virgin Mountains in the Gold Butte step-over region. The basins and faulting patterns suggest two stages of basin development related to two distinct faulting episodes, an early period of detachment faulting followed by a switch to faulting mainly along the Lake Mead transtensional fault system while detachment faulting waned. Apatite fission track ages suggest the footwall block of the SVWHD was cooling at 18-17 Ma, but the only evidence for basin deposition at that time is in the Gold Butte step-over where slow rates of sedimentation and facies patterns make faulting on the north side of the Gold Butte block ambiguous. The first basin stage was ca. 16.5 to 15.5 Ma, during which there was slow to moderate faulting and subsidence in a basin along the SVWHD and north of Gold Butte block in the Gold Butte step-over basin; the step- over basin had complex fluvial and lacustrine facies and was synchronous with landslides and debris flows in front of the SVWHD. At ca. 15.5-14.5 Ma, there was a [dramatic] increase in sedimentation rate related to formation of the Gold Butte fault, a change from lacustrine to widespread fluvial, playa, and local landslide facies in the step-over basin, and the peak of exhumation and faulting rates on the SVWHD. The simple step-over basin broke up into numerous subbasins [at[ as initial faults of the Lake Mead fault system formed. From 14.5 to 14.0 Ma, there was completion of a major change from dominantly detachment faulting to dominantly transtensional faulting
Effect of biosurfactant from two strains of Pseudomonas on ...
PRECIOUS
2009-12-01
Dec 1, 2009 ... Two Pseudomonas strains isolated from oil-contaminated soil which produce biosurfactant were studied. .... Refinery, Assam, India, each having a varied level of oil conta- mination. ..... Rapid method for monitoring maximum.
Guelorget, Bruno [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)]. E-mail: bruno.guelorget@utt.fr; Francois, Manuel [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Vial-Edwards, Cristian [Departemento de Ingenieria Mecanica y Metalurgica, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, 6904411 Santiago (Chile); Montay, Guillaume [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Daniel, Laurent [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Lu, Jian [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)
2006-01-15
In-plane Electronic Speckle Pattern Interferometry has been successfully used during tensile testing of semi-hard copper sheets in order to measure the strain rate. On one hand, heterogeneity in strain rate field has been found before the maximum of the tensile force ({epsilon} {sup t} {approx_equal} 19.4 and 25.4%, respectively). Thus, a localization phenomenon occurs before the classic Considere's criterion (dF = 0) for the diffuse neck initiation. On the other hand, strain rate measurement before fracture shows the moment where one of the two slip band systems becomes predominant, then strain concentrates in a small area, the shear band. Uncertainty evaluation has been carried out, which shows a very good accuracy of the total strain and the strain rate measurements.
Analysis of Photovoltaic Maximum Power Point Trackers
Veerachary, Mummadi
The photovoltaic generator exhibits a non-linear i-v characteristic and its maximum power point (MPP) varies with solar insolation. An intermediate switch-mode dc-dc converter is required to extract maximum power from the photovoltaic array. In this paper buck, boost and buck-boost topologies are considered and a detailed mathematical analysis, both for continuous and discontinuous inductor current operation, is given for MPP operation. The conditions on the connected load values and duty ratio are derived for achieving the satisfactory maximum power point operation. Further, it is shown that certain load values, falling out of the optimal range, will drive the operating point away from the true maximum power point. Detailed comparison of various topologies for MPPT is given. Selection of the converter topology for a given loading is discussed. Detailed discussion on circuit-oriented model development is given and then MPPT effectiveness of various converter systems is verified through simulations. Proposed theory and analysis is validated through experimental investigations.
On maximum cycle packings in polyhedral graphs
Peter Recht
2014-04-01
Full Text Available This paper addresses upper and lower bounds for the cardinality of a maximum vertex-/edge-disjoint cycle packing in a polyhedral graph G. Bounds on the cardinality of such packings are provided, that depend on the size, the order or the number of faces of G, respectively. Polyhedral graphs are constructed, that attain these bounds.
Hard graphs for the maximum clique problem
Hoede, Cornelis
1988-01-01
The maximum clique problem is one of the NP-complete problems. There are graphs for which a reduction technique exists that transforms the problem for these graphs into one for graphs with specific properties in polynomial time. The resulting graphs do not grow exponentially in order and number. Gra
Maximum Likelihood Estimation of Search Costs
J.L. Moraga-Gonzalez (José Luis); M.R. Wildenbeest (Matthijs)
2006-01-01
textabstractIn a recent paper Hong and Shum (forthcoming) present a structural methodology to estimate search cost distributions. We extend their approach to the case of oligopoly and present a maximum likelihood estimate of the search cost distribution. We apply our method to a data set of online p
Weak Scale From the Maximum Entropy Principle
Hamada, Yuta; Kawana, Kiyoharu
2015-01-01
The theory of multiverse and wormholes suggests that the parameters of the Standard Model are fixed in such a way that the radiation of the $S^{3}$ universe at the final stage $S_{rad}$ becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the Standard Model, we can check whether $S_{rad}$ actually becomes maximum at the observed values. In this paper, we regard $S_{rad}$ at the final stage as a function of the weak scale ( the Higgs expectation value ) $v_{h}$, and show that it becomes maximum around $v_{h}={\\cal{O}}(300\\text{GeV})$ when the dimensionless couplings in the Standard Model, that is, the Higgs self coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by \\begin{equation} v_{h}\\sim\\frac{T_{BBN}^{2}}{M_{pl}y_{e}^{5}},\
Weak scale from the maximum entropy principle
Hamada, Yuta; Kawai, Hikaru; Kawana, Kiyoharu
2015-03-01
The theory of the multiverse and wormholes suggests that the parameters of the Standard Model (SM) are fixed in such a way that the radiation of the S3 universe at the final stage S_rad becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the SM, we can check whether S_rad actually becomes maximum at the observed values. In this paper, we regard S_rad at the final stage as a function of the weak scale (the Higgs expectation value) vh, and show that it becomes maximum around vh = {{O}} (300 GeV) when the dimensionless couplings in the SM, i.e., the Higgs self-coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by vh ˜ T_{BBN}2 / (M_{pl}ye5), where ye is the Yukawa coupling of electron, T_BBN is the temperature at which the Big Bang nucleosynthesis starts, and M_pl is the Planck mass.
Global characterization of the Holocene Thermal Maximum
Renssen, H.; Seppä, H.; Crosta, X.; Goosse, H.; Roche, D.M.V.A.P.
2012-01-01
We analyze the global variations in the timing and magnitude of the Holocene Thermal Maximum (HTM) and their dependence on various forcings in transient simulations covering the last 9000 years (9 ka), performed with a global atmosphere-ocean-vegetation model. In these experiments, we consider the i
Instance Optimality of the Adaptive Maximum Strategy
L. Diening; C. Kreuzer; R. Stevenson
2016-01-01
In this paper, we prove that the standard adaptive finite element method with a (modified) maximum marking strategy is instance optimal for the total error, being the square root of the squared energy error plus the squared oscillation. This result will be derived in the model setting of Poisson’s e
Maximum phonation time: variability and reliability.
Speyer, Renée; Bogaardt, Hans C A; Passos, Valéria Lima; Roodenburg, Nel P H D; Zumach, Anne; Heijnen, Mariëlle A M; Baijens, Laura W J; Fleskens, Stijn J H M; Brunings, Jan W
2010-05-01
The objective of the study was to determine maximum phonation time reliability as a function of the number of trials, days, and raters in dysphonic and control subjects. Two groups of adult subjects participated in this reliability study: a group of outpatients with functional or organic dysphonia versus a group of healthy control subjects matched by age and gender. Over a period of maximally 6 weeks, three video recordings were made of five subjects' maximum phonation time trials. A panel of five experts were responsible for all measurements, including a repeated measurement of the subjects' first recordings. Patients showed significantly shorter maximum phonation times compared with healthy controls (on average, 6.6 seconds shorter). The averaged interclass correlation coefficient (ICC) over all raters per trial for the first day was 0.998. The averaged reliability coefficient per rater and per trial for repeated measurements of the first day's data was 0.997, indicating high intrarater reliability. The mean reliability coefficient per day for one trial was 0.939. When using five trials, the reliability increased to 0.987. The reliability over five trials for a single day was 0.836; for 2 days, 0.911; and for 3 days, 0.935. To conclude, the maximum phonation time has proven to be a highly reliable measure in voice assessment. A single rater is sufficient to provide highly reliable measurements.
Maximum Phonation Time: Variability and Reliability
R. Speyer; H.C.A. Bogaardt; V.L. Passos; N.P.H.D. Roodenburg; A. Zumach; M.A.M. Heijnen; L.W.J. Baijens; S.J.H.M. Fleskens; J.W. Brunings
2010-01-01
The objective of the study was to determine maximum phonation time reliability as a function of the number of trials, days, and raters in dysphonic and control subjects. Two groups of adult subjects participated in this reliability study: a group of outpatients with functional or organic dysphonia v
Maximum likelihood estimation of fractionally cointegrated systems
Lasak, Katarzyna
In this paper we consider a fractionally cointegrated error correction model and investigate asymptotic properties of the maximum likelihood (ML) estimators of the matrix of the cointe- gration relations, the degree of fractional cointegration, the matrix of the speed of adjustment...
Maximum likelihood estimation for integrated diffusion processes
Baltazar-Larios, Fernando; Sørensen, Michael
EM-algorithm to obtain maximum likelihood estimates of the parameters in the diffusion model. As part of the algorithm, we use a recent simple method for approximate simulation of diffusion bridges. In simulation studies for the Ornstein-Uhlenbeck process and the CIR process the proposed method works...
Maximum gain of Yagi-Uda arrays
Bojsen, J.H.; Schjær-Jacobsen, Hans; Nilsson, E.
1971-01-01
Numerical optimisation techniques have been used to find the maximum gain of some specific parasitic arrays. The gain of an array of infinitely thin, equispaced dipoles loaded with arbitrary reactances has been optimised. The results show that standard travelling-wave design methods are not optimum....... Yagi–Uda arrays with equal and unequal spacing have also been optimised with experimental verification....
Metabolic networks evolve towards states of maximum entropy production.
Unrean, Pornkamol; Srienc, Friedrich
2011-11-01
A metabolic network can be described by a set of elementary modes or pathways representing discrete metabolic states that support cell function. We have recently shown that in the most likely metabolic state the usage probability of individual elementary modes is distributed according to the Boltzmann distribution law while complying with the principle of maximum entropy production. To demonstrate that a metabolic network evolves towards such state we have carried out adaptive evolution experiments with Thermoanaerobacterium saccharolyticum operating with a reduced metabolic functionality based on a reduced set of elementary modes. In such reduced metabolic network metabolic fluxes can be conveniently computed from the measured metabolite secretion pattern. Over a time span of 300 generations the specific growth rate of the strain continuously increased together with a continuous increase in the rate of entropy production. We show that the rate of entropy production asymptotically approaches the maximum entropy production rate predicted from the state when the usage probability of individual elementary modes is distributed according to the Boltzmann distribution. Therefore, the outcome of evolution of a complex biological system can be predicted in highly quantitative terms using basic statistical mechanical principles.
非良基集合的外延公理%The Axioms of Extensionality of Non-Well-Founded Sets
李娜; 杜文静
2009-01-01
In recent years, since non-well-founded sets have important applications in artifi-cial intelligence, cognitive science and philosophy, there has been a furry of interest in them. How to judge the identity of two objects is the fundamental question in set theory. How-ever, contrary to well founded sets, it is difficult to find the fundamental elements of non-well-founded sets. Thus the ordinary axiom of extensionality can not determine the equality of two non-well-founded sets, for example, the two sets x = {x} and y = {y}. In order to find a criterion to determine the equality of sets involving non-well-founded sets, we need something stronger than the ordinary axiom of extensionality. According to the four non-well-founded axioms (AFA, SAFA, FAFA, and BAFA) introduced by Aczel, we deduce four criteria for equality of non-well-founded sets. Furthermore, we illustrate how to use our criteria to determine the equality for two given non-well-founded sets by examples, so such problem of equality be-tween "circular sets" has been solved. In addition, we also account for that the four criteria are the extensions of the ordinary axiom of extensionality, not replacement of it. To this end, in this paper we first present some basic definitions and results of sets and graph; secondly, we discuss the four set universes A, S, F, and B determined respectively by four non-well-founded axioms AFA, SAFA, FAFA, and BAFA; lastly, we study the extension of the ordinary axiom of extensionality.%近年来,由于非良基集合在人工智能、认知科学及哲学等领域都有很重要的应用,它的研究越来越受到人们的关注.判断两个对象的同一性是集合论中最基本的问题,然而,与良基集合不同的是,非良基集合难以找到其最基本的组成成分,这样通常的外延公理就无法判断两个非良基集合(例如x={x}和y={y})相等.为了找到判断两个非良基集合相等的标准,我们必须强化
Hu, Tingting; Tian, Nan; Ali, Sarmad; Wang, Zhen; Chang, Jiarui; Huang, Ningdong; Li, Liangbin
2016-03-01
The crystallization of poly(ethylene oxide) (PEO)-sodium iodine (NaI) composites is investigated by differential scanning calorimetry (DSC), extensional rheology, and in situ small-angle X-ray scattering (SAXS) with the aim of demonstrating versatile roles played by polymer-ion interactions. In the isothermal quiescent crystallization process, a decrease in the crystal growth rate is observed for PEO-NaI and is attributed to slow chain movement caused by the coordination between cations and polymer. In situ SAXS on extensional flow-induced crystallization (FIC) exhibits enhanced kinetics and orientation for both PEO and PEO-NaI with increasing strain rate. However, an overall weaker strain-rate dependence of FIC is observed for PEO-NaI, which can be interpreted as a synergistic consequence of promoted nucleation under flow and impeded crystal growth by polymer-ion interaction. A possible microscopic mechanism is proposed to account for the experimental observation based on the formation of transient cross-linking points in PEO-NaI and their influence on the entanglement network of polymer under various flow fields. The disclosed strain-rate dependence and various ion effects on the behavior of PEO-salt composites contribute to a comprehensive understanding of polymer-ion solid polyelectrolytes.
Morris, R.; DeBari, S. M.; Busby, C.; Medynski, S.
2016-12-01
The southern volcano-bounded basin of the Rosario segment of the Cretaceous Alisitos oceanic arc provides outstanding 3-D exposures of an extensional arc, where crustal generation processes are recorded in the upper-crustal volcanic units and underlying middle-crustal plutonic rocks. Geochemical linkages between exposed crustal levels provide an analog for extensional arc systems such as the Izu-Bonin-Mariana (IBM) Arc. Upper-crustal units comprise a 3-5 km thick volcanic-volcaniclastic stratigraphy with hypabyssal intrusions. Deep-seated plutonic rocks intrude these units over a transition of overlap. The most mafic compositions occur in upper-crustal hypabyssal units, and as amphibole cumulates in the plutonic rocks ( 51% SiO2). The most felsic compositions occur in welded ignimbrites and a tonalite pluton ( 71% SiO2). All units are low K with flat REE patterns, and show LILE enrichment and HFSE depletion. Trace element ratios show limited variation throughout the crustal section. Zr/Y and Nb/Y ratios are similar to the Izu active ( 3 Ma to present) zone of extension immediately behind the arc front, suggesting comparable mantle melt % during extension. Th/Zr ratios are more enriched in Alisitos compared to Izu, suggesting greater subducted sediment input. The Alisitos crustal section shows a limited range in ɛNd (5.7-7.1), but a wider range in 87Sr/86Sr (0.7035-0.7055) and 206Pb/204Pb (18.12-19.12); the latter is likely alteration effects. Arc magmas were derived from a subduction-modified MORB mantle source, less depleted than Izu arc front and less enriched than the rear arc, but is a good match with the zone of extension that lies between. Differentiation occurred in a closed system (i.e., fractional crystallization/self-melting with back mixing), producing the entire crustal section in <3 Ma.
Oswaldo Siga Junior
2011-12-01
Full Text Available The aim of this work is the presentation of a synthesis of available geochronological data for the basement inliers andmetavolcano-sedimentary sequences which occur in the southern part of the Apiaí Terrane, south-southeastern Brazil.These data, especially those obtained during the last decade, have made substantial modifi cations to the tectonic scenarioof south-southeastern Brazil with the recognition of the presence of extensional basins (continental rifts with magmatismand sedimentation at the late Paleoproterozoic (1790 - 1750 Ma and of the Mesoproterozoic (1600 - 1450 Ma. Theseprocesses started at the late Paleoproterozoic in the Betara, Perau and Apiai Mirim Nuclei, and the basins became widerduring the Mesoproterozoic with the deposition of the Betara, Perau, Votuverava and Água Clara metavolcano-sedimentarysequences. A different pattern is found for the Itaicoca Sequence which occupies the northern part of the Apiaí Terrain.Here two rock associations of different ages are found. The fi rst is a metamorphosed carbonate platform association withsubalkaline, tholeiitic metabasic rocks with minimum deposition ages at the end of the Mesoproterozoic or beginning of theNeoproterozoic (Itaiacoca Sequence; 1030 - 900 Ma, while the second mainly contains metapsammites and metavolcanicrocks including ultrapotassic trachytes deposited during the Cryogenian-Ediacaran transition between 645 and 628 Ma(Abapã Sequence. It is then proposed that the present scenario of the Apiaí Terrane be representative of the distincttectono-sedimentary histories, refl ecting a polycyclic evolution. In the Mesoproterozoic, stable conditions prevailed, withthe deposition of the majority of the sequences (Lajeado, Água Clara, Betara, Perau, Votuverava in a passive margincontext, succeded by a Tonian extensional phase (deposition of the Itaiacoca Sequence. In the Ediacaran the region wastransformed into an unstable active margin, with the predominance of magmatic
María VICTORIA-MAS
2017-01-01
Full Text Available Las marcas periodísticas encuentran en las plataformas digitales una gran oportunidad de mantener y aumentar el valor que tienen. Solo una minoría de empresas informativas tradicionales ha desarrollado estrategias de gestión de ese valor. Cuando las extensiones digitales no son coherentes con las marcas madre, pueden diluir su imagen y acabar siendo contraproducentes. Este artículo explora hasta qué punto las marcas de prensa utilizan sus extensiones digitales para aumentar su valor y cómo comunican su marca a través de ellas. La metodología escogida para ello es el análisis de contenidos de las ediciones online y de los perfiles en redes sociales de las 44 cabeceras más leídas en España. Los resultados indican que esas marcas no han explotado aún todo el potencial que las plataformas online tienen para ganar valor. Realizan solo una comunicación parcial de sí mismas y no han llevado a cabo algunas de las acciones que se consideran prioritarias en la gestión estratégica de la marca, tales como la definición de la identidad y la concreción de la misión. La discusión de los resultados permite proponer algunas estrategias de creación de valor de marca en las empresas informativas.
The 3-D strain patterns in Turkey using geodetic velocity fields from the RTK-CORS (TR) network
Kutoglu, Hakan Senol; Toker, Mustafa; Mekik, Cetin
2016-03-01
This study presents our use of GPS data to obtain and quantify the full continuous strain tensor using a 3-D velocity field in Turkey. In this study, GPS velocities improve the estimation of short-term strain tensor fields for determining the seismic hazard of Turkey. The tensorial analysis presents different aspects of deformation, such as the normal and shear strains, including their directions, the compressional and extensional strains. This analysis is appropriate for the characterizing the state of the current seismic deformation. GPS velocity data from continuous measurements (2009-2012) to estimate deformations were processed using the GAMIT/GLOBK software. Using high-rate GPS data from permanent 146 GNSS stations (RTK-CORS-TR network), the strain distribution was determined and interpolated using a biharmonic spline technique. We show the strain field patterns within axial and plane form at several critical locations, and discuss these results within the context of the seismic and tectonic deformation of Turkey. We conclude that the knowledge of the crustal strain patterns provides important information on the location of the main faults and strain accumulation for the hazard assessment. The results show an agreement between the seismic and tectonic strains confirming that there are active crustal deformations in Turkey.
Model Selection Through Sparse Maximum Likelihood Estimation
Banerjee, Onureena; D'Aspremont, Alexandre
2007-01-01
We consider the problem of estimating the parameters of a Gaussian or binary distribution in such a way that the resulting undirected graphical model is sparse. Our approach is to solve a maximum likelihood problem with an added l_1-norm penalty term. The problem as formulated is convex but the memory requirements and complexity of existing interior point methods are prohibitive for problems with more than tens of nodes. We present two new algorithms for solving problems with at least a thousand nodes in the Gaussian case. Our first algorithm uses block coordinate descent, and can be interpreted as recursive l_1-norm penalized regression. Our second algorithm, based on Nesterov's first order method, yields a complexity estimate with a better dependence on problem size than existing interior point methods. Using a log determinant relaxation of the log partition function (Wainwright & Jordan (2006)), we show that these same algorithms can be used to solve an approximate sparse maximum likelihood problem for...
Maximum-entropy description of animal movement.
Fleming, Chris H; Subaşı, Yiğit; Calabrese, Justin M
2015-03-01
We introduce a class of maximum-entropy states that naturally includes within it all of the major continuous-time stochastic processes that have been applied to animal movement, including Brownian motion, Ornstein-Uhlenbeck motion, integrated Ornstein-Uhlenbeck motion, a recently discovered hybrid of the previous models, and a new model that describes central-place foraging. We are also able to predict a further hierarchy of new models that will emerge as data quality improves to better resolve the underlying continuity of animal movement. Finally, we also show that Langevin equations must obey a fluctuation-dissipation theorem to generate processes that fall from this class of maximum-entropy distributions when the constraints are purely kinematic.
Pareto versus lognormal: a maximum entropy test.
Bee, Marco; Riccaboni, Massimo; Schiavo, Stefano
2011-08-01
It is commonly found that distributions that seem to be lognormal over a broad range change to a power-law (Pareto) distribution for the last few percentiles. The distributions of many physical, natural, and social events (earthquake size, species abundance, income and wealth, as well as file, city, and firm sizes) display this structure. We present a test for the occurrence of power-law tails in statistical distributions based on maximum entropy. This methodology allows one to identify the true data-generating processes even in the case when it is neither lognormal nor Pareto. The maximum entropy approach is then compared with other widely used methods and applied to different levels of aggregation of complex systems. Our results provide support for the theory that distributions with lognormal body and Pareto tail can be generated as mixtures of lognormally distributed units.
Maximum Variance Hashing via Column Generation
Lei Luo
2013-01-01
item search. Recently, a number of data-dependent methods have been developed, reflecting the great potential of learning for hashing. Inspired by the classic nonlinear dimensionality reduction algorithm—maximum variance unfolding, we propose a novel unsupervised hashing method, named maximum variance hashing, in this work. The idea is to maximize the total variance of the hash codes while preserving the local structure of the training data. To solve the derived optimization problem, we propose a column generation algorithm, which directly learns the binary-valued hash functions. We then extend it using anchor graphs to reduce the computational cost. Experiments on large-scale image datasets demonstrate that the proposed method outperforms state-of-the-art hashing methods in many cases.
The Maximum Resource Bin Packing Problem
Boyar, J.; Epstein, L.; Favrholdt, L.M.
2006-01-01
algorithms, First-Fit-Increasing and First-Fit-Decreasing for the maximum resource variant of classical bin packing. For the on-line variant, we define maximum resource variants of classical and dual bin packing. For dual bin packing, no on-line algorithm is competitive. For classical bin packing, we find......Usually, for bin packing problems, we try to minimize the number of bins used or in the case of the dual bin packing problem, maximize the number or total size of accepted items. This paper presents results for the opposite problems, where we would like to maximize the number of bins used...... the competitive ratio of various natural algorithms. We study the general versions of the problems as well as the parameterized versions where there is an upper bound of on the item sizes, for some integer k....
Nonparametric Maximum Entropy Estimation on Information Diagrams
Martin, Elliot A; Meinke, Alexander; Děchtěrenko, Filip; Davidsen, Jörn
2016-01-01
Maximum entropy estimation is of broad interest for inferring properties of systems across many different disciplines. In this work, we significantly extend a technique we previously introduced for estimating the maximum entropy of a set of random discrete variables when conditioning on bivariate mutual informations and univariate entropies. Specifically, we show how to apply the concept to continuous random variables and vastly expand the types of information-theoretic quantities one can condition on. This allows us to establish a number of significant advantages of our approach over existing ones. Not only does our method perform favorably in the undersampled regime, where existing methods fail, but it also can be dramatically less computationally expensive as the cardinality of the variables increases. In addition, we propose a nonparametric formulation of connected informations and give an illustrative example showing how this agrees with the existing parametric formulation in cases of interest. We furthe...
Zipf's law, power laws and maximum entropy
Visser, Matt
2013-04-01
Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines—from astronomy to demographics to software structure to economics to linguistics to zoology, and even warfare. A recent model of random group formation (RGF) attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present paper I argue that the specific cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified.
Zipf's law, power laws, and maximum entropy
Visser, Matt
2012-01-01
Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines - from astronomy to demographics to economics to linguistics to zoology, and even warfare. A recent model of random group formation [RGF] attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present article I argue that the cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified.
Regions of constrained maximum likelihood parameter identifiability
Lee, C.-H.; Herget, C. J.
1975-01-01
This paper considers the parameter identification problem of general discrete-time, nonlinear, multiple-input/multiple-output dynamic systems with Gaussian-white distributed measurement errors. Knowledge of the system parameterization is assumed to be known. Regions of constrained maximum likelihood (CML) parameter identifiability are established. A computation procedure employing interval arithmetic is proposed for finding explicit regions of parameter identifiability for the case of linear systems. It is shown that if the vector of true parameters is locally CML identifiable, then with probability one, the vector of true parameters is a unique maximal point of the maximum likelihood function in the region of parameter identifiability and the CML estimation sequence will converge to the true parameters.
A Maximum Radius for Habitable Planets.
Alibert, Yann
2015-09-01
We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope.
Strain-based fatigue data for Ti-6Al-4V ELI under fully-reversed and mean strain loads.
Carrion, Patricio E; Shamsaei, Nima
2016-06-01
This article presents the experimental data supporting the study to obtain the mean strain/stress effects on the fatigue behavior of Ti-6Al-4V ELI. A series of strain-controlled fatigue experiments on Ti-6Al-4V ELI were performed at four strain ratios (-1, -0.5, 0, and 0.5). Two types of data are included for each specimen. These are the hysteresis stress-strain responses for the cycle in a log10 increment, and the maximum and minimum stress-strain responses for each cycle. Fatigue lives are also reported for all the experiments.
Strain-based fatigue data for Ti–6Al–4V ELI under fully-reversed and mean strain loads
Carrion, Patricio E.; Shamsaei, Nima
2016-01-01
This article presents the experimental data supporting the study to obtain the mean strain/stress effects on the fatigue behavior of Ti–6Al–4V ELI. A series of strain-controlled fatigue experiments on Ti–6Al–4V ELI were performed at four strain ratios (−1, −0.5, 0, and 0.5). Two types of data are included for each specimen. These are the hysteresis stress–strain responses for the cycle in a log10 increment, and the maximum and minimum stress–strain responses for each cycle. Fatigue lives are also reported for all the experiments. PMID:26952022
Strain-based fatigue data for Ti–6Al–4V ELI under fully-reversed and mean strain loads
Patricio E. Carrion
2016-06-01
Full Text Available This article presents the experimental data supporting the study to obtain the mean strain/stress effects on the fatigue behavior of Ti–6Al–4V ELI. A series of strain-controlled fatigue experiments on Ti–6Al–4V ELI were performed at four strain ratios (−1, −0.5, 0, and 0.5. Two types of data are included for each specimen. These are the hysteresis stress–strain responses for the cycle in a log10 increment, and the maximum and minimum stress–strain responses for each cycle. Fatigue lives are also reported for all the experiments.
Maximum Profit Configurations of Commercial Engines
Yiran Chen
2011-01-01
An investigation of commercial engines with finite capacity low- and high-price economic subsystems and a generalized commodity transfer law [n ∝ Δ (P m)] in commodity flow processes, in which effects of the price elasticities of supply and demand are introduced, is presented in this paper. Optimal cycle configurations of commercial engines for maximum profit are obtained by applying optimal control theory. In some special cases, the eventual state—market equilibrium—is solely determined by t...
A stochastic maximum principle via Malliavin calculus
Øksendal, Bernt; Zhou, Xun Yu; Meyer-Brandis, Thilo
2008-01-01
This paper considers a controlled It\\^o-L\\'evy process where the information available to the controller is possibly less than the overall information. All the system coefficients and the objective performance functional are allowed to be random, possibly non-Markovian. Malliavin calculus is employed to derive a maximum principle for the optimal control of such a system where the adjoint process is explicitly expressed.
Tissue radiation response with maximum Tsallis entropy.
Sotolongo-Grau, O; Rodríguez-Pérez, D; Antoranz, J C; Sotolongo-Costa, Oscar
2010-10-08
The expression of survival factors for radiation damaged cells is currently based on probabilistic assumptions and experimentally fitted for each tumor, radiation, and conditions. Here, we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. The obtained expression shows a remarkable agreement with the experimental data found in the literature.
Maximum Estrada Index of Bicyclic Graphs
Wang, Long; Wang, Yi
2012-01-01
Let $G$ be a simple graph of order $n$, let $\\lambda_1(G),\\lambda_2(G),...,\\lambda_n(G)$ be the eigenvalues of the adjacency matrix of $G$. The Esrada index of $G$ is defined as $EE(G)=\\sum_{i=1}^{n}e^{\\lambda_i(G)}$. In this paper we determine the unique graph with maximum Estrada index among bicyclic graphs with fixed order.
Maximum privacy without coherence, zero-error
Leung, Debbie; Yu, Nengkun
2016-09-01
We study the possible difference between the quantum and the private capacities of a quantum channel in the zero-error setting. For a family of channels introduced by Leung et al. [Phys. Rev. Lett. 113, 030512 (2014)], we demonstrate an extreme difference: the zero-error quantum capacity is zero, whereas the zero-error private capacity is maximum given the quantum output dimension.
Quantifying strain variability in modeling growth of Listeria monocytogenes
Aryani, D.; Besten, den H.M.W.; Hazeleger, W.C.; Zwietering, M.H.
2015-01-01
Prediction of microbial growth kinetics can differ from the actual behavior of the target microorganisms. In the present study, the impact of strain variability on maximum specific growth rate (µmax) (h- 1) was quantified using twenty Listeria monocytogenes strains. The µmax was determined as functi
Automatic maximum entropy spectral reconstruction in NMR.
Mobli, Mehdi; Maciejewski, Mark W; Gryk, Michael R; Hoch, Jeffrey C
2007-10-01
Developments in superconducting magnets, cryogenic probes, isotope labeling strategies, and sophisticated pulse sequences together have enabled the application, in principle, of high-resolution NMR spectroscopy to biomolecular systems approaching 1 megadalton. In practice, however, conventional approaches to NMR that utilize the fast Fourier transform, which require data collected at uniform time intervals, result in prohibitively lengthy data collection times in order to achieve the full resolution afforded by high field magnets. A variety of approaches that involve nonuniform sampling have been proposed, each utilizing a non-Fourier method of spectrum analysis. A very general non-Fourier method that is capable of utilizing data collected using any of the proposed nonuniform sampling strategies is maximum entropy reconstruction. A limiting factor in the adoption of maximum entropy reconstruction in NMR has been the need to specify non-intuitive parameters. Here we describe a fully automated system for maximum entropy reconstruction that requires no user-specified parameters. A web-accessible script generator provides the user interface to the system.
Maximum entropy analysis of cosmic ray composition
Nosek, Dalibor; Vícha, Jakub; Trávníček, Petr; Nosková, Jana
2016-01-01
We focus on the primary composition of cosmic rays with the highest energies that cause extensive air showers in the Earth's atmosphere. A way of examining the two lowest order moments of the sample distribution of the depth of shower maximum is presented. The aim is to show that useful information about the composition of the primary beam can be inferred with limited knowledge we have about processes underlying these observations. In order to describe how the moments of the depth of shower maximum depend on the type of primary particles and their energies, we utilize a superposition model. Using the principle of maximum entropy, we are able to determine what trends in the primary composition are consistent with the input data, while relying on a limited amount of information from shower physics. Some capabilities and limitations of the proposed method are discussed. In order to achieve a realistic description of the primary mass composition, we pay special attention to the choice of the parameters of the sup...
A Maximum Resonant Set of Polyomino Graphs
Zhang Heping
2016-05-01
Full Text Available A polyomino graph P is a connected finite subgraph of the infinite plane grid such that each finite face is surrounded by a regular square of side length one and each edge belongs to at least one square. A dimer covering of P corresponds to a perfect matching. Different dimer coverings can interact via an alternating cycle (or square with respect to them. A set of disjoint squares of P is a resonant set if P has a perfect matching M so that each one of those squares is M-alternating. In this paper, we show that if K is a maximum resonant set of P, then P − K has a unique perfect matching. We further prove that the maximum forcing number of a polyomino graph is equal to the cardinality of a maximum resonant set. This confirms a conjecture of Xu et al. [26]. We also show that if K is a maximal alternating set of P, then P − K has a unique perfect matching.
The maximum rate of mammal evolution
Evans, Alistair R.; Jones, David; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Fitzgerald, Erich M. G.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica M.; Uhen, Mark D.
2012-03-01
How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.
Minimal Length, Friedmann Equations and Maximum Density
Awad, Adel
2014-01-01
Inspired by Jacobson's thermodynamic approach[gr-qc/9504004], Cai et al [hep-th/0501055,hep-th/0609128] have shown the emergence of Friedmann equations from the first law of thermodynamics. We extend Akbar--Cai derivation [hep-th/0609128] of Friedmann equations to accommodate a general entropy-area law. Studying the resulted Friedmann equations using a specific entropy-area law, which is motivated by the generalized uncertainty principle (GUP), reveals the existence of a maximum energy density closed to Planck density. Allowing for a general continuous pressure $p(\\rho,a)$ leads to bounded curvature invariants and a general nonsingular evolution. In this case, the maximum energy density is reached in a finite time and there is no cosmological evolution beyond this point which leaves the big bang singularity inaccessible from a spacetime prospective. The existence of maximum energy density and a general nonsingular evolution is independent of the equation of state and the spacial curvature $k$. As an example w...
Maximum saliency bias in binocular fusion
Lu, Yuhao; Stafford, Tom; Fox, Charles
2016-07-01
Subjective experience at any instant consists of a single ("unitary"), coherent interpretation of sense data rather than a "Bayesian blur" of alternatives. However, computation of Bayes-optimal actions has no role for unitary perception, instead being required to integrate over every possible action-percept pair to maximise expected utility. So what is the role of unitary coherent percepts, and how are they computed? Recent work provided objective evidence for non-Bayes-optimal, unitary coherent, perception and action in humans; and further suggested that the percept selected is not the maximum a posteriori percept but is instead affected by utility. The present study uses a binocular fusion task first to reproduce the same effect in a new domain, and second, to test multiple hypotheses about exactly how utility may affect the percept. After accounting for high experimental noise, it finds that both Bayes optimality (maximise expected utility) and the previously proposed maximum-utility hypothesis are outperformed in fitting the data by a modified maximum-salience hypothesis, using unsigned utility magnitudes in place of signed utilities in the bias function.
The maximum rate of mammal evolution
Evans, Alistair R.; Jones, David; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Fitzgerald, Erich M. G.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica M.; Uhen, Mark D.
2012-01-01
How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous–Paleogene (K–Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes. PMID:22308461
The maximum rate of mammal evolution.
Evans, Alistair R; Jones, David; Boyer, Alison G; Brown, James H; Costa, Daniel P; Ernest, S K Morgan; Fitzgerald, Erich M G; Fortelius, Mikael; Gittleman, John L; Hamilton, Marcus J; Harding, Larisa E; Lintulaakso, Kari; Lyons, S Kathleen; Okie, Jordan G; Saarinen, Juha J; Sibly, Richard M; Smith, Felisa A; Stephens, Patrick R; Theodor, Jessica M; Uhen, Mark D
2012-03-13
How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.
Maximum power operation of interacting molecular motors
Golubeva, Natalia; Imparato, Alberto
2013-01-01
We study the mechanical and thermodynamic properties of different traffic models for kinesin which are relevant in biological and experimental contexts. We find that motor-motor interactions play a fundamental role by enhancing the thermodynamic efficiency at maximum power of the motors......, as compared to the non-interacting system, in a wide range of biologically compatible scenarios. We furthermore consider the case where the motor-motor interaction directly affects the internal chemical cycle and investigate the effect on the system dynamics and thermodynamics....
Maximum a posteriori decoder for digital communications
Altes, Richard A. (Inventor)
1997-01-01
A system and method for decoding by identification of the most likely phase coded signal corresponding to received data. The present invention has particular application to communication with signals that experience spurious random phase perturbations. The generalized estimator-correlator uses a maximum a posteriori (MAP) estimator to generate phase estimates for correlation with incoming data samples and for correlation with mean phases indicative of unique hypothesized signals. The result is a MAP likelihood statistic for each hypothesized transmission, wherein the highest value statistic identifies the transmitted signal.
Kernel-based Maximum Entropy Clustering
JIANG Wei; QU Jiao; LI Benxi
2007-01-01
With the development of Support Vector Machine (SVM),the "kernel method" has been studied in a general way.In this paper,we present a novel Kernel-based Maximum Entropy Clustering algorithm (KMEC).By using mercer kernel functions,the proposed algorithm is firstly map the data from their original space to high dimensional space where the data are expected to be more separable,then perform MEC clustering in the feature space.The experimental results show that the proposed method has better performance in the non-hyperspherical and complex data structure.
The sun and heliosphere at solar maximum.
Smith, E J; Marsden, R G; Balogh, A; Gloeckler, G; Geiss, J; McComas, D J; McKibben, R B; MacDowall, R J; Lanzerotti, L J; Krupp, N; Krueger, H; Landgraf, M
2003-11-14
Recent Ulysses observations from the Sun's equator to the poles reveal fundamental properties of the three-dimensional heliosphere at the maximum in solar activity. The heliospheric magnetic field originates from a magnetic dipole oriented nearly perpendicular to, instead of nearly parallel to, the Sun's rotation axis. Magnetic fields, solar wind, and energetic charged particles from low-latitude sources reach all latitudes, including the polar caps. The very fast high-latitude wind and polar coronal holes disappear and reappear together. Solar wind speed continues to be inversely correlated with coronal temperature. The cosmic ray flux is reduced symmetrically at all latitudes.
Conductivity maximum in a charged colloidal suspension
Bastea, S
2009-01-27
Molecular dynamics simulations of a charged colloidal suspension in the salt-free regime show that the system exhibits an electrical conductivity maximum as a function of colloid charge. We attribute this behavior to two main competing effects: colloid effective charge saturation due to counterion 'condensation' and diffusion slowdown due to the relaxation effect. In agreement with previous observations, we also find that the effective transported charge is larger than the one determined by the Stern layer and suggest that it corresponds to the boundary fluid layer at the surface of the colloidal particles.
Maximum entropy signal restoration with linear programming
Mastin, G.A.; Hanson, R.J.
1988-05-01
Dantzig's bounded-variable method is used to express the maximum entropy restoration problem as a linear programming problem. This is done by approximating the nonlinear objective function with piecewise linear segments, then bounding the variables as a function of the number of segments used. The use of a linear programming approach allows equality constraints found in the traditional Lagrange multiplier method to be relaxed. A robust revised simplex algorithm is used to implement the restoration. Experimental results from 128- and 512-point signal restorations are presented.
COMPARISON BETWEEN FORMULAS OF MAXIMUM SHIP SQUAT
PETRU SERGIU SERBAN
2016-06-01
Full Text Available Ship squat is a combined effect of ship’s draft and trim increase due to ship motion in limited navigation conditions. Over time, researchers conducted tests on models and ships to find a mathematical formula that can define squat. Various forms of calculating squat can be found in the literature. Among those most commonly used are of Barrass, Millward, Eryuzlu or ICORELS. This paper presents a comparison between the squat formulas to see the differences between them and which one provides the most satisfactory results. In this respect a cargo ship at different speeds was considered as a model for maximum squat calculations in canal navigation conditions.
Multi-Channel Maximum Likelihood Pitch Estimation
Christensen, Mads Græsbøll
2012-01-01
In this paper, a method for multi-channel pitch estimation is proposed. The method is a maximum likelihood estimator and is based on a parametric model where the signals in the various channels share the same fundamental frequency but can have different amplitudes, phases, and noise characteristics....... This essentially means that the model allows for different conditions in the various channels, like different signal-to-noise ratios, microphone characteristics and reverberation. Moreover, the method does not assume that a certain array structure is used but rather relies on a more general model and is hence...
Maximum entropy PDF projection: A review
Baggenstoss, Paul M.
2017-06-01
We review maximum entropy (MaxEnt) PDF projection, a method with wide potential applications in statistical inference. The method constructs a sampling distribution for a high-dimensional vector x based on knowing the sampling distribution p(z) of a lower-dimensional feature z = T (x). Under mild conditions, the distribution p(x) having highest possible entropy among all distributions consistent with p(z) may be readily found. Furthermore, the MaxEnt p(x) may be sampled, making the approach useful in Monte Carlo methods. We review the theorem and present a case study in model order selection and classification for handwritten character recognition.
CORA: Emission Line Fitting with Maximum Likelihood
Ness, Jan-Uwe; Wichmann, Rainer
2011-12-01
CORA analyzes emission line spectra with low count numbers and fits them to a line using the maximum likelihood technique. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise, the software derives the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. CORA has been applied to an X-ray spectrum with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory.
Dynamical maximum entropy approach to flocking
Cavagna, Andrea; Giardina, Irene; Ginelli, Francesco; Mora, Thierry; Piovani, Duccio; Tavarone, Raffaele; Walczak, Aleksandra M.
2014-04-01
We derive a new method to infer from data the out-of-equilibrium alignment dynamics of collectively moving animal groups, by considering the maximum entropy model distribution consistent with temporal and spatial correlations of flight direction. When bird neighborhoods evolve rapidly, this dynamical inference correctly learns the parameters of the model, while a static one relying only on the spatial correlations fails. When neighbors change slowly and the detailed balance is satisfied, we recover the static procedure. We demonstrate the validity of the method on simulated data. The approach is applicable to other systems of active matter.
Maximum Temperature Detection System for Integrated Circuits
Frankiewicz, Maciej; Kos, Andrzej
2015-03-01
The paper describes structure and measurement results of the system detecting present maximum temperature on the surface of an integrated circuit. The system consists of the set of proportional to absolute temperature sensors, temperature processing path and a digital part designed in VHDL. Analogue parts of the circuit where designed with full-custom technique. The system is a part of temperature-controlled oscillator circuit - a power management system based on dynamic frequency scaling method. The oscillator cooperates with microprocessor dedicated for thermal experiments. The whole system is implemented in UMC CMOS 0.18 μm (1.8 V) technology.
Zipf's law and maximum sustainable growth
Malevergne, Y; Sornette, D
2010-01-01
Zipf's law states that the number of firms with size greater than S is inversely proportional to S. Most explanations start with Gibrat's rule of proportional growth but require additional constraints. We show that Gibrat's rule, at all firm levels, yields Zipf's law under a balance condition between the effective growth rate of incumbent firms (which includes their possible demise) and the growth rate of investments in entrant firms. Remarkably, Zipf's law is the signature of the long-term optimal allocation of resources that ensures the maximum sustainable growth rate of an economy.
Prediction Models on Distribution of Inherent Strains in T Type Welding Structure
Peng HE; Jicai FENG; Jiecai HAN; Yiyu QIAN
2003-01-01
A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. The method of predicting maximum hardness Hv(y, z) and maximum inherent strain gmax is given
Accurate structural correlations from maximum likelihood superpositions.
Douglas L Theobald
2008-02-01
Full Text Available The cores of globular proteins are densely packed, resulting in complicated networks of structural interactions. These interactions in turn give rise to dynamic structural correlations over a wide range of time scales. Accurate analysis of these complex correlations is crucial for understanding biomolecular mechanisms and for relating structure to function. Here we report a highly accurate technique for inferring the major modes of structural correlation in macromolecules using likelihood-based statistical analysis of sets of structures. This method is generally applicable to any ensemble of related molecules, including families of nuclear magnetic resonance (NMR models, different crystal forms of a protein, and structural alignments of homologous proteins, as well as molecular dynamics trajectories. Dominant modes of structural correlation are determined using principal components analysis (PCA of the maximum likelihood estimate of the correlation matrix. The correlations we identify are inherently independent of the statistical uncertainty and dynamic heterogeneity associated with the structural coordinates. We additionally present an easily interpretable method ("PCA plots" for displaying these positional correlations by color-coding them onto a macromolecular structure. Maximum likelihood PCA of structural superpositions, and the structural PCA plots that illustrate the results, will facilitate the accurate determination of dynamic structural correlations analyzed in diverse fields of structural biology.
Maximum entropy production and the fluctuation theorem
Dewar, R C [Unite EPHYSE, INRA Centre de Bordeaux-Aquitaine, BP 81, 33883 Villenave d' Ornon Cedex (France)
2005-05-27
Recently the author used an information theoretical formulation of non-equilibrium statistical mechanics (MaxEnt) to derive the fluctuation theorem (FT) concerning the probability of second law violating phase-space paths. A less rigorous argument leading to the variational principle of maximum entropy production (MEP) was also given. Here a more rigorous and general mathematical derivation of MEP from MaxEnt is presented, and the relationship between MEP and the FT is thereby clarified. Specifically, it is shown that the FT allows a general orthogonality property of maximum information entropy to be extended to entropy production itself, from which MEP then follows. The new derivation highlights MEP and the FT as generic properties of MaxEnt probability distributions involving anti-symmetric constraints, independently of any physical interpretation. Physically, MEP applies to the entropy production of those macroscopic fluxes that are free to vary under the imposed constraints, and corresponds to selection of the most probable macroscopic flux configuration. In special cases MaxEnt also leads to various upper bound transport principles. The relationship between MaxEnt and previous theories of irreversible processes due to Onsager, Prigogine and Ziegler is also clarified in the light of these results. (letter to the editor)
Thermodynamic hardness and the maximum hardness principle
Franco-Pérez, Marco; Gázquez, José L.; Ayers, Paul W.; Vela, Alberto
2017-08-01
An alternative definition of hardness (called the thermodynamic hardness) within the grand canonical ensemble formalism is proposed in terms of the partial derivative of the electronic chemical potential with respect to the thermodynamic chemical potential of the reservoir, keeping the temperature and the external potential constant. This temperature dependent definition may be interpreted as a measure of the propensity of a system to go through a charge transfer process when it interacts with other species, and thus it keeps the philosophy of the original definition. When the derivative is expressed in terms of the three-state ensemble model, in the regime of low temperatures and up to temperatures of chemical interest, one finds that for zero fractional charge, the thermodynamic hardness is proportional to T-1(I -A ) , where I is the first ionization potential, A is the electron affinity, and T is the temperature. However, the thermodynamic hardness is nearly zero when the fractional charge is different from zero. Thus, through the present definition, one avoids the presence of the Dirac delta function. We show that the chemical hardness defined in this way provides meaningful and discernible information about the hardness properties of a chemical species exhibiting integer or a fractional average number of electrons, and this analysis allowed us to establish a link between the maximum possible value of the hardness here defined, with the minimum softness principle, showing that both principles are related to minimum fractional charge and maximum stability conditions.
Maximum Likelihood Analysis in the PEN Experiment
Lehman, Martin
2013-10-01
The experimental determination of the π+ -->e+ ν (γ) decay branching ratio currently provides the most accurate test of lepton universality. The PEN experiment at PSI, Switzerland, aims to improve the present world average experimental precision of 3 . 3 ×10-3 to 5 ×10-4 using a stopped beam approach. During runs in 2008-10, PEN has acquired over 2 ×107 πe 2 events. The experiment includes active beam detectors (degrader, mini TPC, target), central MWPC tracking with plastic scintillator hodoscopes, and a spherical pure CsI electromagnetic shower calorimeter. The final branching ratio will be calculated using a maximum likelihood analysis. This analysis assigns each event a probability for 5 processes (π+ -->e+ ν , π+ -->μ+ ν , decay-in-flight, pile-up, and hadronic events) using Monte Carlo verified probability distribution functions of our observables (energies, times, etc). A progress report on the PEN maximum likelihood analysis will be presented. Work supported by NSF grant PHY-0970013.
A numerical method for determining the strain rate intensity factor under plane strain conditions
Alexandrov, S.; Kuo, C.-Y.; Jeng, Y.-R.
2016-07-01
Using the classical model of rigid perfectly plastic solids, the strain rate intensity factor has been previously introduced as the coefficient of the leading singular term in a series expansion of the equivalent strain rate in the vicinity of maximum friction surfaces. Since then, many strain rate intensity factors have been determined by means of analytical and semi-analytical solutions. However, no attempt has been made to develop a numerical method for calculating the strain rate intensity factor. This paper presents such a method for planar flow. The method is based on the theory of characteristics. First, the strain rate intensity factor is derived in characteristic coordinates. Then, a standard numerical slip-line technique is supplemented with a procedure to calculate the strain rate intensity factor. The distribution of the strain rate intensity factor along the friction surface in compression of a layer between two parallel plates is determined. A high accuracy of this numerical solution for the strain rate intensity factor is confirmed by comparison with an analytic solution. It is shown that the distribution of the strain rate intensity factor is in general discontinuous.
Miller, E. L.; Dumitru, T.; Brumley, K.; Gottlieb, E.; Meisling, K.; Akinin, V.
2012-04-01
Relevant data are compiled and synthesized across Arctic Alaska and Russia with the goal of establishing spatial and temporal connections between rifting in the Eurasia and Amerasia basins of the Arctic Ocean and extension within the circum-Arctic landmasses. Although timing, direction and magnitude of continental extension are still poorly known, geochronologic and thermochronologic studies have proven to be an excellent means of bracketing extension-related tilting, uplift and denudation (e.g. Brooks Range, Seward Peninsula, Lisburne Hills and Wrangel Island). The south flank of the Brooks Range, Seward Peninsula, Bering Strait, Chukotka and Wrangel Island all underwent large magnitude N-S extension that regionally overlaps in age with the intrusion of 120-90 Ma plutons and the formation of deep marine basins in Alaska. This widespread extension is traditionally attributed to paleo-Pacific slab rollback following Jura-Cretaceous (~160-140?Ma) convergence and shortening. Westward across Chukotka, extensional (and strike-slip?) structures were also coeval with ~120-90 Ma magmatism, but are more poorly documented. By contrast, extensional structures west of longitude 175° in Chukotka (and offshore Siberian Shelf) appear to have developed in response to E-W, rather than N-S extension. The South Annui Zone and its inferred continuation to the Siberian Islands appears to separate (by ~1300 km) similar sequences with identical source regions, suggesting right-lateral transform or accommodation of E-W to WNW-ESE extension to the north. Its motion was likely over by the ~88-90 Ma eruption of the Okhotsk-Chukotka volcanic belt, linked to the reconfiguration of paleo-Pacific subduction. Large ~E-W trending shelfal basins in the Bering Strait region formed in latest Cretaceous (?) to early Tertiary (N. and S. Chukchi, Hope, Norton, Anadyr and St. Matthew basins). In Siberia, N-S trending extensional structures of the Laptev Sea are related to southward propagation of Gakkel
Lake Basin Fetch and Maximum Length/Width
Minnesota Department of Natural Resources — Linear features representing the Fetch, Maximum Length and Maximum Width of a lake basin. Fetch, maximum length and average width are calcuated from the lake polygon...
Obturator internus muscle strains
Caoimhe Byrne, MB BCh, BAO
2017-03-01
Full Text Available We report 2 cases of obturator internus muscle strains. The injuries occurred in young male athletes involved in kicking sports. Case 1 details an acute obturator internus muscle strain with associated adductor longus strain. Case 2 details an overuse injury of the bilateral obturator internus muscles. In each case, magnetic resonance imaging played a crucial role in accurate diagnosis.
Elitez, İrem; Yaltırak, Cenk; Aktuǧ, Bahadır
2016-04-01
The southwestern Turkey is one of the most tectonically active areas of the eastern Mediterranean and therefore is a controversial region from the geodynamic point of view. This complex tectonic regime is dominated by the westward escape of Anatolia related to North Anatolian Fault, Aegean back-arc extension regime due to roll-back of Hellenic Arc, the subduction transform edge propagator (STEP) fault zone related to the motion of Hellenic and Cyprus arcs and compressional regime of Tauride Mountains. In addition to that, an active subduction and seamounts moving towards the north determine the tectonic frame of the Eastern Mediterranean. Many researchers suggest either the existence of a single left lateral fault or the nonexistence of a fault zone between Western Anatolia and Western Taurides. According to the integration of digital elevation data, non-commercial GoogleEarth satellite images and field studies, a 300 km-long 75-90 km-wide NE-SW-trending left lateral shear zone, the Burdur-Fethiye Shear Zone, is located among these tectonic structures. By using GPS velocities and focal mechanism solutions of earthquakes, it is understood that most of the previous studies turn a blind eye to the hundreds of faults related to a left-lateral shear zone which will have an important role in the Mediterrenean tectonics. The Burdur-Fethiye Shear Zone is like a zipper driven by the relative velocity differences due to the Aegean back-arc extensional system and Western Taurides compressional region and presents a high seismic activity. The GPS vectors reflect remarkable velocity differences on land and relatedly the significant topographic differences can be clearly observed. According to the GPS vectors, the Aegean region moves 4-12 mm/yr faster than the wesward escape of the Anatolia towards southwest and the velocities are low in the Western Taurides. The left-lateral differential motion across the Burdur-Fethiye Shear Zone varies from 3-4 mm/yr in the north side to 8
Metabolic activities of Lactobacillus spp. strains isolated from kefir.
Yüksekdag, Zehra Nur; Beyath, Yavuz; Aslim, Belma
2004-06-01
A total of 21 strains of Lactobacillus species were isolated from Turkish kefir samples, in order to select the most suitable strains according to their metabolic activities including probiotic properties. As a result of the identification tests, 21 Lactobacillus isolates were identified as L. acidophilus (4%), L. helveticus (9%), L. brevis (9%), L. bulgaricus (14%), L. plantarum (14%), L. casei (19%) and L. lactis (28%). The amount of produced lactic acid, hydrogen peroxide, proteolytic activity, and acetaldehyde productions of Lactobacillus spp. were determined. Different amounts of lactic acid were produced by strains studies; however, lactic acid levels were 1.7-11.4 mg/mL. All strains produced hydrogen peroxide. L. bulgaricus Z14L strain showed no proteolytic activity, L. casei Z6L strain produced the maximum amount (0.16 mg/mL) of proteolytic activity. Acetaldehyde concentration produced in Lactobacillus strains ranged between 0.88-3.52 microg/mL.
Maximum entropy principle and texture formation
Arminjon, M; Arminjon, Mayeul; Imbault, Didier
2006-01-01
The macro-to-micro transition in a heterogeneous material is envisaged as the selection of a probability distribution by the Principle of Maximum Entropy (MAXENT). The material is made of constituents, e.g. given crystal orientations. Each constituent is itself made of a large number of elementary constituents. The relevant probability is the volume fraction of the elementary constituents that belong to a given constituent and undergo a given stimulus. Assuming only obvious constraints in MAXENT means describing a maximally disordered material. This is proved to have the same average stimulus in each constituent. By adding a constraint in MAXENT, a new model, potentially interesting e.g. for texture prediction, is obtained.
MLDS: Maximum Likelihood Difference Scaling in R
Kenneth Knoblauch
2008-01-01
Full Text Available The MLDS package in the R programming language can be used to estimate perceptual scales based on the results of psychophysical experiments using the method of difference scaling. In a difference scaling experiment, observers compare two supra-threshold differences (a,b and (c,d on each trial. The approach is based on a stochastic model of how the observer decides which perceptual difference (or interval (a,b or (c,d is greater, and the parameters of the model are estimated using a maximum likelihood criterion. We also propose a method to test the model by evaluating the self-consistency of the estimated scale. The package includes an example in which an observer judges the differences in correlation between scatterplots. The example may be readily adapted to estimate perceptual scales for arbitrary physical continua.
Maximum Profit Configurations of Commercial Engines
Yiran Chen
2011-06-01
Full Text Available An investigation of commercial engines with finite capacity low- and high-price economic subsystems and a generalized commodity transfer law [n ∝ Δ (P m] in commodity flow processes, in which effects of the price elasticities of supply and demand are introduced, is presented in this paper. Optimal cycle configurations of commercial engines for maximum profit are obtained by applying optimal control theory. In some special cases, the eventual state—market equilibrium—is solely determined by the initial conditions and the inherent characteristics of two subsystems; while the different ways of transfer affect the model in respects of the specific forms of the paths of prices and the instantaneous commodity flow, i.e., the optimal configuration.
Maximum Segment Sum, Monadically (distilled tutorial
Jeremy Gibbons
2011-09-01
Full Text Available The maximum segment sum problem is to compute, given a list of integers, the largest of the sums of the contiguous segments of that list. This problem specification maps directly onto a cubic-time algorithm; however, there is a very elegant linear-time solution too. The problem is a classic exercise in the mathematics of program construction, illustrating important principles such as calculational development, pointfree reasoning, algebraic structure, and datatype-genericity. Here, we take a sideways look at the datatype-generic version of the problem in terms of monadic functional programming, instead of the traditional relational approach; the presentation is tutorial in style, and leavened with exercises for the reader.
Maximum Information and Quantum Prediction Algorithms
McElwaine, J N
1997-01-01
This paper describes an algorithm for selecting a consistent set within the consistent histories approach to quantum mechanics and investigates its properties. The algorithm uses a maximum information principle to select from among the consistent sets formed by projections defined by the Schmidt decomposition. The algorithm unconditionally predicts the possible events in closed quantum systems and ascribes probabilities to these events. A simple spin model is described and a complete classification of all exactly consistent sets of histories formed from Schmidt projections in the model is proved. This result is used to show that for this example the algorithm selects a physically realistic set. Other tentative suggestions in the literature for set selection algorithms using ideas from information theory are discussed.
Maximum process problems in optimal control theory
Goran Peskir
2005-01-01
Full Text Available Given a standard Brownian motion (Btt≥0 and the equation of motion dXt=vtdt+2dBt, we set St=max0≤s≤tXs and consider the optimal control problem supvE(Sτ−Cτ, where c>0 and the supremum is taken over all admissible controls v satisfying vt∈[μ0,μ1] for all t up to τ=inf{t>0|Xt∉(ℓ0,ℓ1} with μ0g∗(St, where s↦g∗(s is a switching curve that is determined explicitly (as the unique solution to a nonlinear differential equation. The solution found demonstrates that the problem formulations based on a maximum functional can be successfully included in optimal control theory (calculus of variations in addition to the classic problem formulations due to Lagrange, Mayer, and Bolza.
Maximum Spectral Luminous Efficacy of White Light
Murphy, T W
2013-01-01
As lighting efficiency improves, it is useful to understand the theoretical limits to luminous efficacy for light that we perceive as white. Independent of the efficiency with which photons are generated, there exists a spectrally-imposed limit to the luminous efficacy of any source of photons. We find that, depending on the acceptable bandpass and---to a lesser extent---the color temperature of the light, the ideal white light source achieves a spectral luminous efficacy of 250--370 lm/W. This is consistent with previous calculations, but here we explore the maximum luminous efficacy as a function of photopic sensitivity threshold, color temperature, and color rendering index; deriving peak performance as a function of all three parameters. We also present example experimental spectra from a variety of light sources, quantifying the intrinsic efficacy of their spectral distributions.
Maximum entropy model for business cycle synchronization
Xi, Ning; Muneepeerakul, Rachata; Azaele, Sandro; Wang, Yougui
2014-11-01
The global economy is a complex dynamical system, whose cyclical fluctuations can mainly be characterized by simultaneous recessions or expansions of major economies. Thus, the researches on the synchronization phenomenon are key to understanding and controlling the dynamics of the global economy. Based on a pairwise maximum entropy model, we analyze the business cycle synchronization of the G7 economic system. We obtain a pairwise-interaction network, which exhibits certain clustering structure and accounts for 45% of the entire structure of the interactions within the G7 system. We also find that the pairwise interactions become increasingly inadequate in capturing the synchronization as the size of economic system grows. Thus, higher-order interactions must be taken into account when investigating behaviors of large economic systems.
Quantum gravity momentum representation and maximum energy
Moffat, J. W.
2016-11-01
We use the idea of the symmetry between the spacetime coordinates xμ and the energy-momentum pμ in quantum theory to construct a momentum space quantum gravity geometry with a metric sμν and a curvature tensor Pλ μνρ. For a closed maximally symmetric momentum space with a constant 3-curvature, the volume of the p-space admits a cutoff with an invariant maximum momentum a. A Wheeler-DeWitt-type wave equation is obtained in the momentum space representation. The vacuum energy density and the self-energy of a charged particle are shown to be finite, and modifications of the electromagnetic radiation density and the entropy density of a system of particles occur for high frequencies.
Video segmentation using Maximum Entropy Model
QIN Li-juan; ZHUANG Yue-ting; PAN Yun-he; WU Fei
2005-01-01
Detecting objects of interest from a video sequence is a fundamental and critical task in automated visual surveillance.Most current approaches only focus on discriminating moving objects by background subtraction whether or not the objects of interest can be moving or stationary. In this paper, we propose layers segmentation to detect both moving and stationary target objects from surveillance video. We extend the Maximum Entropy (ME) statistical model to segment layers with features, which are collected by constructing a codebook with a set of codewords for each pixel. We also indicate how the training models are used for the discrimination of target objects in surveillance video. Our experimental results are presented in terms of the success rate and the segmenting precision.
Parallel Microcracks-based Ultrasensitive and Highly Stretchable Strain Sensors.
Amjadi, Morteza; Turan, Mehmet; Clementson, Cameron P; Sitti, Metin
2016-03-01
There is an increasing demand for flexible, skin-attachable, and wearable strain sensors due to their various potential applications. However, achieving strain sensors with both high sensitivity and high stretchability is still a grand challenge. Here, we propose highly sensitive and stretchable strain sensors based on the reversible microcrack formation in composite thin films. Controllable parallel microcracks are generated in graphite thin films coated on elastomer films. Sensors made of graphite thin films with short microcracks possess high gauge factors (maximum value of 522.6) and stretchability (ε ≥ 50%), whereas sensors with long microcracks show ultrahigh sensitivity (maximum value of 11,344) with limited stretchability (ε ≤ 50%). We demonstrate the high performance strain sensing of our sensors in both small and large strain sensing applications such as human physiological activity recognition, human body large motion capturing, vibration detection, pressure sensing, and soft robotics.
Evaluation of pliers' grip spans in the maximum gripping task and sub-maximum cutting task.
Kim, Dae-Min; Kong, Yong-Ku
2016-12-01
A total of 25 males participated to investigate the effects of the grip spans of pliers on the total grip force, individual finger forces and muscle activities in the maximum gripping task and wire-cutting tasks. In the maximum gripping task, results showed that the 50-mm grip span had significantly higher total grip strength than the other grip spans. In the cutting task, the 50-mm grip span also showed significantly higher grip strength than the 65-mm and 80-mm grip spans, whereas the muscle activities showed a higher value at 80-mm grip span. The ratios of cutting force to maximum grip strength were also investigated. Ratios of 30.3%, 31.3% and 41.3% were obtained by grip spans of 50-mm, 65-mm, and 80-mm, respectively. Thus, the 50-mm grip span for pliers might be recommended to provide maximum exertion in gripping tasks, as well as lower maximum-cutting force ratios in the cutting tasks.
Cosmic shear measurement with maximum likelihood and maximum a posteriori inference
Hall, Alex
2016-01-01
We investigate the problem of noise bias in maximum likelihood and maximum a posteriori estimators for cosmic shear. We derive the leading and next-to-leading order biases and compute them in the context of galaxy ellipticity measurements, extending previous work on maximum likelihood inference for weak lensing. We show that a large part of the bias on these point estimators can be removed using information already contained in the likelihood when a galaxy model is specified, without the need for external calibration. We test these bias-corrected estimators on simulated galaxy images similar to those expected from planned space-based weak lensing surveys, with very promising results. We find that the introduction of an intrinsic shape prior mitigates noise bias, such that the maximum a posteriori estimate can be made less biased than the maximum likelihood estimate. Second-order terms offer a check on the convergence of the estimators, but are largely sub-dominant. We show how biases propagate to shear estima...
2016-01-01
The invention relates to a strain gauge of a carrier layer and a meandering measurement grid positioned on the carrier layer, wherein the strain gauge comprises two reinforcement members positioned on the carrier layer at opposite ends of the measurement grid in the axial direction....... The reinforcement members are each placed within a certain axial distance to the measurement grid with the axial distance being equal to or smaller than a factor times the grid spacing. The invention further relates to a multi-axial strain gauge such as a bi-axial strain gauge or a strain gauge rosette where each...... of the strain gauges comprises reinforcement members. The invention further relates to a method for manufacturing a strain gauge as mentioned above....
Ground movement at Somma-Vesuvius from Last Glacial Maximum
Marturano, Aldo; Aiello, Giuseppe; Barra, Diana; Fedele, Lorenzo; Morra, Vincenzo
2012-01-01
Detailed micropalaeontological and petrochemical analyses of rock samples from two boreholes drilled at the archaeological excavations of Herculaneum, ~ 7 km west of the Somma -Vesuvius crater, allowed reconstruction of the Late Quaternary palaeoenvironmental evolution of the site. The data provide clear evidence for ground uplift movements involving the studied area. The Holocenic sedimentary sequence on which the archaeological remains of Herculaneum rest has risen several meters at an average rate of ~ 4 mm/yr. The uplift has involved the western apron of the volcano and the Sebeto-Volla Plain, a populous area including the eastern suburbs of Naples. This is consistent with earlier evidence for similar uplift for the areas of Pompeii and Sarno valley (SE of the volcano) and the Somma -Vesuvius eastern apron. An axisimmetric deep source of strain is considered responsible for the long-term uplift affecting the whole Somma -Vesuvius edifice. The deformation pattern can be modeled as a single pressure source, sited in the lower crust and surrounded by a shell of Maxwell viscoelastic medium, which experienced a pressure pulse that began at the Last Glacial Maximum.
Pitra, Pavel; Poujol, Marc; Van Den Driessche, Jean; Poilvet, Jean-Charles; Paquette, Jean-Louis
2012-08-01
Dating the magmatic events in the Montagne Noire gneiss dome is a key point to arbitrate between the different interpretations of the Late Carboniferous-Early Permian tectonics in this southern part of the Variscan belt. The Saint-Eutrope orthogneiss crops out along the northern flank of the dome. We show that the protolith of this orthogneiss is an Ordovician granite dated at 455 ± 2 Ma (LA-ICP-MS U-Pb dating on zircon). This age is identical to that previously obtained on the augen orthogneiss of the southern flank, strongly suggesting that both orthogneiss occurrences have the same Ordovician protolith. The Saint-Eutrope orthogneiss experienced intense shearing along the Espinouse extensional detachment at ca. 295 Ma (LA-ICP-MS U-Pb-Th on monazite), an age close to that determined previously on mica by the 39Ar-40Ar method and contemporaneous with the emplacement age of the syntectonic Montalet granite farther to the west. This normal sense shearing reworked previous fabrics related to Variscan thrusting that can be still observed in the augen orthogneiss of the southern flank, and is responsible for the spectacular "C/S-like" pattern of the Saint-Eutrope orthogneiss. This work also shows that care is needed when dealing with C/S-type structures, since they can develop not only in syntectonic intrusions, but also in orthogneisses affected by an intense secondary deformation, at decreasing temperature.
Stojadinovic, Uros; Matenco, Liviu; Andriessen, Paul; Toljić, Marinko; Rundić, Ljupko; Ducea, Mihai N.
2017-07-01
The NE part of the Dinarides Mountain chain, located near their junction with the Carpatho-Balkanides, is an area where sedimentary basins associated with the Neotethys subduction and collision are still exposed. We performed a provenance study, based on detrital fission track thermochronology combined with zircon Usbnd Pb magmatic geochronology, and existing studies of kinematics and exhumation. Our study shows rapid sedimentation in the trench and forearc basin overlying the upper European tectonic plate. A number of latest Cretaceous-Early Paleocene igneous provenance ages show a dominant magmatic source area, derived from a Late Cretaceous subduction-related arc. This arc shed short time lag sediments in the forearc and the trench system, possibly associated with focused exhumation in the Serbo-Macedonian margin. This was followed by burial of the trench sediments and a novel stage of Middle-Late Eocene exhumation driven by continued continental collision that had larger effects than previously thought. The collision was followed by Late Oligocene-Miocene exhumation of the former lower Adriatic plate along extensional detachments that reactivated the inherited collisional contact along the entire Dinarides margin. This event re-distributed sediments at short distances in the neighboring Miocene basins. Our study demonstrates that the Dinarides orogenic system is characterized by short lag times between exhumation and re-deposition, whereas the upper tectonic plate is significantly exhumed only during the final stages of collision. Such an exhumation pattern is not directly obvious from observing the overall geometry of the orogen.
You, Weilong; Pei, Binbin; Sun, Ke; Zhang, Lei; Yang, Heng; Li, Xinxin
2017-10-01
This paper presents an oven controlled N++ [1 0 0] length-extensional mode silicon resonator, with a lookup-table based control algorithm. The temperature coefficient of resonant frequency (TCF) of the N++ doped resonator is nonlinear, and there is a turnover temperature point at which the TCF is equal to zero. The resonator is maintained at the turnover point by Joule heating; this temperature is a little higher than the upper limit of the industrial temperature range. It is demonstrated that the control algorithm based on the thermoresistor on the substrate and the lookup table for heating voltage versus chip temperature is sufficiently accurate to achieve a frequency stability of ±0.5 ppm over the industrial temperature range. Because only two leads are required for electrical heating and piezoresistive sensing, the power required for heating of this resonator can be potentially lower than that of the oscillators with closed-loop oven control algorithm. It is also shown that the phase noise can be suppressed at the turnover temperature because of the very low value of the TCF, which justifies the usage of the heating voltage as the excitation voltage of the Wheatstone half-bridge.
Shah, N. Y.; Reed, X. B., Jr.
1995-01-01
Forced convective diffusion-reaction is considered for viscous axisymmetric extensional convecting velocity in the neighborhood of a sphere. For Peclet numbers in the range 0.1 less than or equal to Pe less than or equal to 500 and for Damkohler numbers increasing with increasing Pe but in the overall range 0.02 less than or equal to Da less than or equal to 10, average and local Sherwood numbers have been computed. By introducing the eigenfunction expansion c(r, Theta) = Sum of c(n)(r)P(n)(cos Theta) into the forced convective diffusion equation for the concentration of a chemical species undergoing a first order homogeneous reaction and by using properties of the Legendre functions Pn(cos Theta), the variable coefficient PDE can be reduced to a system of N + 1 second order ODEs for the radial functions c(sub n)(r), n = 0, 1, 2,..., N. The adaptive grid algorithm of Pereyra and Lentini can be used to solve the corresponding 2(N + 1) first order differential equations as a two-point boundary value problem on 1 less than or equal to r less than or equal to r(sub infinity). Convergence of the expansion for a specific value of N can thus be established and provides 'spectral' behavior as well as the full concentration field c(r, Theta).
Longitudinal growth strains in five clones of Eucalyptus tereticornis Sm.
Pankaj Aggarwal; Shakti Chauhan
2013-01-01
We studied the variability in longitudinal growth strains and wood basic density in five-year old trees from five clones (one tree per clone) of Eucalyptus tereticornis.Mean longitudinal growth strain in clones ranged from 466 to 876 μm.There was a significant difference between clones in growth strains and wood basic density.Clone 10 exhibited maximum growth strains and basic density,whereas clone 3 and clone 7 exhibited minimum growth strains and basic density,respectively.Within a tree,the growth strain variation with tree height was high but statistically insignificant while within tree variation in basic density was very small.There was no specific trend in variation in either strain or density within a tree.There was 5％-200％ difference in growth strain on opposite sides of the logs.However two strains showed a strong positive correlation.There was a moderate positive association of wood basic density and mean growth strains in logs.The variation around the periphery emphasize the need to measure strain more than one,preferably on opposite sides at the same height,on a tree to know the mean strain level for the purpose of selection of clones.
Modelling to very high strains
Bons, P. D.; Jessell, M. W.; Griera, A.; Evans, L. A.; Wilson, C. J. L.
2009-04-01
Ductile strains in shear zones often reach extreme values, resulting in typical structures, such as winged porphyroclasts and several types of shear bands. The numerical simulation of the development of such structures has so far been inhibited by the low maximum strains that numerical models can normally achieve. Typical numerical models collapse at shear strains in the order of one to three. We have implemented a number of new functionalities in the numerical platform "Elle" (Jessell et al. 2001), which significantly increases the amount of strain that can be achieved and simultaneously reduces boundary effects that become increasingly disturbing at higher strain. Constant remeshing, while maintaining the polygonal phase regions, is the first step to avoid collapse of the finite-element grid required by finite-element solvers, such as Basil (Houseman et al. 2008). The second step is to apply a grain-growth routine to the boundaries of polygons that represent phase regions. This way, the development of sharp angles is avoided. A second advantage is that phase regions may merge or become separated (boudinage). Such topological changes are normally not possible in finite element deformation codes. The third step is the use of wrapping vertical model boundaries, with which optimal and unchanging model boundaries are maintained for the application of stress or velocity boundary conditions. The fourth step is to shift the model by a random amount in the vertical direction every time step. This way, the fixed horizontal boundary conditions are applied to different material points within the model every time step. Disturbing boundary effects are thus averaged out over the whole model and not localised to e.g. top and bottom of the model. Reduction of boundary effects has the additional advantage that model can be smaller and, therefore, numerically more efficient. Owing to the combination of these existing and new functionalities it is now possible to simulate the
20 CFR 211.14 - Maximum creditable compensation.
2010-04-01
... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Maximum creditable compensation. 211.14... CREDITABLE RAILROAD COMPENSATION § 211.14 Maximum creditable compensation. Maximum creditable compensation... Employment Accounts shall notify each employer of the amount of maximum creditable compensation applicable...
49 CFR 230.24 - Maximum allowable stress.
2010-10-01
... 49 Transportation 4 2010-10-01 2010-10-01 false Maximum allowable stress. 230.24 Section 230.24... Allowable Stress § 230.24 Maximum allowable stress. (a) Maximum allowable stress value. The maximum allowable stress value on any component of a steam locomotive boiler shall not exceed 1/4 of the ultimate...
A tunable strain sensor using nanogranular metals.
Schwalb, Christian H; Grimm, Christina; Baranowski, Markus; Sachser, Roland; Porrati, Fabrizio; Reith, Heiko; Das, Pintu; Müller, Jens; Völklein, Friedemann; Kaya, Alexander; Huth, Michael
2010-01-01
This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID) employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me)(3)]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor) of the sensor element. We find that its sensitivity depends on the electrical conductivity and can be continuously tuned, either by the thickness of the deposit or by electron-beam irradiation leading to a distinct maximum in the sensitivity. This maximum finds a theoretical rationale in recent advances in the understanding of electronic charge transport in nano-granular metals.
A Tunable Strain Sensor Using Nanogranular Metals
Friedemann Völklein
2010-11-01
Full Text Available This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me3]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor of the sensor element. We find that its sensitivity depends on the electrical conductivity and can be continuously tuned, either by the thickness of the deposit or by electron-beam irradiation leading to a distinct maximum in the sensitivity. This maximum finds a theoretical rationale in recent advances in the understanding of electronic charge transport in nano-granular metals.
A Tunable Strain Sensor Using Nanogranular Metals
Schwalb, Christian H.; Grimm, Christina; Baranowski, Markus; Sachser, Roland; Porrati, Fabrizio; Reith, Heiko; Das, Pintu; Müller, Jens; Völklein, Friedemann; Kaya, Alexander; Huth, Michael
2010-01-01
This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID) employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me)3]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor) of the sensor element. We find that its sensitivity depends on the electrical conductivity and can be continuously tuned, either by the thickness of the deposit or by electron-beam irradiation leading to a distinct maximum in the sensitivity. This maximum finds a theoretical rationale in recent advances in the understanding of electronic charge transport in nano-granular metals. PMID:22163443
Theoretical Estimate of Maximum Possible Nuclear Explosion
Bethe, H. A.
1950-01-31
The maximum nuclear accident which could occur in a Na-cooled, Be moderated, Pu and power producing reactor is estimated theoretically. (T.R.H.) 2O82 Results of nuclear calculations for a variety of compositions of fast, heterogeneous, sodium-cooled, U-235-fueled, plutonium- and power-producing reactors are reported. Core compositions typical of plate-, pin-, or wire-type fuel elements and with uranium as metal, alloy, and oxide were considered. These compositions included atom ratios in the following range: U-23B to U-235 from 2 to 8; sodium to U-235 from 1.5 to 12; iron to U-235 from 5 to 18; and vanadium to U-235 from 11 to 33. Calculations were performed to determine the effect of lead and iron reflectors between the core and blanket. Both natural and depleted uranium were evaluated as the blanket fertile material. Reactors were compared on a basis of conversion ratio, specific power, and the product of both. The calculated results are in general agreement with the experimental results from fast reactor assemblies. An analysis of the effect of new cross-section values as they became available is included. (auth)
Proposed principles of maximum local entropy production.
Ross, John; Corlan, Alexandru D; Müller, Stefan C
2012-07-12
Articles have appeared that rely on the application of some form of "maximum local entropy production principle" (MEPP). This is usually an optimization principle that is supposed to compensate for the lack of structural information and measurements about complex systems, even systems as complex and as little characterized as the whole biosphere or the atmosphere of the Earth or even of less known bodies in the solar system. We select a number of claims from a few well-known papers that advocate this principle and we show that they are in error with the help of simple examples of well-known chemical and physical systems. These erroneous interpretations can be attributed to ignoring well-established and verified theoretical results such as (1) entropy does not necessarily increase in nonisolated systems, such as "local" subsystems; (2) macroscopic systems, as described by classical physics, are in general intrinsically deterministic-there are no "choices" in their evolution to be selected by using supplementary principles; (3) macroscopic deterministic systems are predictable to the extent to which their state and structure is sufficiently well-known; usually they are not sufficiently known, and probabilistic methods need to be employed for their prediction; and (4) there is no causal relationship between the thermodynamic constraints and the kinetics of reaction systems. In conclusion, any predictions based on MEPP-like principles should not be considered scientifically founded.
Maximum entropy production and plant optimization theories.
Dewar, Roderick C
2010-05-12
Plant ecologists have proposed a variety of optimization theories to explain the adaptive behaviour and evolution of plants from the perspective of natural selection ('survival of the fittest'). Optimization theories identify some objective function--such as shoot or canopy photosynthesis, or growth rate--which is maximized with respect to one or more plant functional traits. However, the link between these objective functions and individual plant fitness is seldom quantified and there remains some uncertainty about the most appropriate choice of objective function to use. Here, plants are viewed from an alternative thermodynamic perspective, as members of a wider class of non-equilibrium systems for which maximum entropy production (MEP) has been proposed as a common theoretical principle. I show how MEP unifies different plant optimization theories that have been proposed previously on the basis of ad hoc measures of individual fitness--the different objective functions of these theories emerge as examples of entropy production on different spatio-temporal scales. The proposed statistical explanation of MEP, that states of MEP are by far the most probable ones, suggests a new and extended paradigm for biological evolution--'survival of the likeliest'--which applies from biomacromolecules to ecosystems, not just to individuals.
Maximum likelihood continuity mapping for fraud detection
Hogden, J.
1997-05-01
The author describes a novel time-series analysis technique called maximum likelihood continuity mapping (MALCOM), and focuses on one application of MALCOM: detecting fraud in medical insurance claims. Given a training data set composed of typical sequences, MALCOM creates a stochastic model of sequence generation, called a continuity map (CM). A CM maximizes the probability of sequences in the training set given the model constraints, CMs can be used to estimate the likelihood of sequences not found in the training set, enabling anomaly detection and sequence prediction--important aspects of data mining. Since MALCOM can be used on sequences of categorical data (e.g., sequences of words) as well as real valued data, MALCOM is also a potential replacement for database search tools such as N-gram analysis. In a recent experiment, MALCOM was used to evaluate the likelihood of patient medical histories, where ``medical history`` is used to mean the sequence of medical procedures performed on a patient. Physicians whose patients had anomalous medical histories (according to MALCOM) were evaluated for fraud by an independent agency. Of the small sample (12 physicians) that has been evaluated, 92% have been determined fraudulent or abusive. Despite the small sample, these results are encouraging.
Maximum life spiral bevel reduction design
Savage, M.; Prasanna, M. G.; Coe, H. H.
1992-07-01
Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ratio under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed back-cone distance of the spiral bevel gear set for a specified speed ratio, shaft angle, input torque, and power. Significant parameters in the design are: the spiral angle, the pressure angle, the numbers of teeth on the pinion and gear, and the location and size of the four support bearings. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for gradient optimization. After finding the continuous optimum, a designer can analyze near optimal designs for comparison and selection. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.
CORA - emission line fitting with Maximum Likelihood
Ness, J.-U.; Wichmann, R.
2002-07-01
The advent of pipeline-processed data both from space- and ground-based observatories often disposes of the need of full-fledged data reduction software with its associated steep learning curve. In many cases, a simple tool doing just one task, and doing it right, is all one wishes. In this spirit we introduce CORA, a line fitting tool based on the maximum likelihood technique, which has been developed for the analysis of emission line spectra with low count numbers and has successfully been used in several publications. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise we derive the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. As an example we demonstrate the functionality of the program with an X-ray spectrum of Capella obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory and choose the analysis of the Ne IX triplet around 13.5 Å.
Finding maximum JPEG image block code size
Lakhani, Gopal
2012-07-01
We present a study of JPEG baseline coding. It aims to determine the minimum storage needed to buffer the JPEG Huffman code bits of 8-bit image blocks. Since DC is coded separately, and the encoder represents each AC coefficient by a pair of run-length/AC coefficient level, the net problem is to perform an efficient search for the optimal run-level pair sequence. We formulate it as a two-dimensional, nonlinear, integer programming problem and solve it using a branch-and-bound based search method. We derive two types of constraints to prune the search space. The first one is given as an upper-bound for the sum of squares of AC coefficients of a block, and it is used to discard sequences that cannot represent valid DCT blocks. The second type constraints are based on some interesting properties of the Huffman code table, and these are used to prune sequences that cannot be part of optimal solutions. Our main result is that if the default JPEG compression setting is used, space of minimum of 346 bits and maximum of 433 bits is sufficient to buffer the AC code bits of 8-bit image blocks. Our implementation also pruned the search space extremely well; the first constraint reduced the initial search space of 4 nodes down to less than 2 nodes, and the second set of constraints reduced it further by 97.8%.
Maximum likelihood estimates of pairwise rearrangement distances.
Serdoz, Stuart; Egri-Nagy, Attila; Sumner, Jeremy; Holland, Barbara R; Jarvis, Peter D; Tanaka, Mark M; Francis, Andrew R
2017-06-21
Accurate estimation of evolutionary distances between taxa is important for many phylogenetic reconstruction methods. Distances can be estimated using a range of different evolutionary models, from single nucleotide polymorphisms to large-scale genome rearrangements. Corresponding corrections for genome rearrangement distances fall into 3 categories: Empirical computational studies, Bayesian/MCMC approaches, and combinatorial approaches. Here, we introduce a maximum likelihood estimator for the inversion distance between a pair of genomes, using a group-theoretic approach to modelling inversions introduced recently. This MLE functions as a corrected distance: in particular, we show that because of the way sequences of inversions interact with each other, it is quite possible for minimal distance and MLE distance to differently order the distances of two genomes from a third. The second aspect tackles the problem of accounting for the symmetries of circular arrangements. While, generally, a frame of reference is locked, and all computation made accordingly, this work incorporates the action of the dihedral group so that distance estimates are free from any a priori frame of reference. The philosophy of accounting for symmetries can be applied to any existing correction method, for which examples are offered. Copyright © 2017 Elsevier Ltd. All rights reserved.
Boedeker, Peter
2017-01-01
Hierarchical linear modeling (HLM) is a useful tool when analyzing data collected from groups. There are many decisions to be made when constructing and estimating a model in HLM including which estimation technique to use. Three of the estimation techniques available when analyzing data with HLM are maximum likelihood, restricted maximum…
Strain y strain rate para dummies
Pastor Olaya, MD
2011-11-01
Full Text Available Desarrollos recientes en el campo de la ecocardiografía han permitido a los cardiólogos cuantificar de manera objetiva la función miocárdica regional y global con base en los conceptos de deformación (strain y velocidad de deformación (strain rate que pueden calcularse de manera no invasiva tanto en el ventrículo izquierdo como en el derecho, y suministrar valiosa información en múltiples escenarios clínicos. Dado que esta técnica novedosa y promisoria se utiliza cada vez más en la clínica y en estudios de investigación, se hace necesario el conocimiento adecuado de sus principios, así como de sus aspectos técnicos, alcances y limitaciones para una mejor implementación. En este artículo se busca dar explicación a los conceptos fundamentales y las potenciales aplicaciones clínicas de la strain y la strain rate derivados por speckle tracking (strain 2D.
Maximum likelihood molecular clock comb: analytic solutions.
Chor, Benny; Khetan, Amit; Snir, Sagi
2006-04-01
Maximum likelihood (ML) is increasingly used as an optimality criterion for selecting evolutionary trees, but finding the global optimum is a hard computational task. Because no general analytic solution is known, numeric techniques such as hill climbing or expectation maximization (EM), are used in order to find optimal parameters for a given tree. So far, analytic solutions were derived only for the simplest model--three taxa, two state characters, under a molecular clock. Four taxa rooted trees have two topologies--the fork (two subtrees with two leaves each) and the comb (one subtree with three leaves, the other with a single leaf). In a previous work, we devised a closed form analytic solution for the ML molecular clock fork. In this work, we extend the state of the art in the area of analytic solutions ML trees to the family of all four taxa trees under the molecular clock assumption. The change from the fork topology to the comb incurs a major increase in the complexity of the underlying algebraic system and requires novel techniques and approaches. We combine the ultrametric properties of molecular clock trees with the Hadamard conjugation to derive a number of topology dependent identities. Employing these identities, we substantially simplify the system of polynomial equations. We finally use tools from algebraic geometry (e.g., Gröbner bases, ideal saturation, resultants) and employ symbolic algebra software to obtain analytic solutions for the comb. We show that in contrast to the fork, the comb has no closed form solutions (expressed by radicals in the input data). In general, four taxa trees can have multiple ML points. In contrast, we can now prove that under the molecular clock assumption, the comb has a unique (local and global) ML point. (Such uniqueness was previously shown for the fork.).
Three dimensional strained semiconductors
Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui
2016-11-08
In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.
Maiti, CK
2012-01-01
Currently strain engineering is the main technique used to enhance the performance of advanced silicon-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Written from an engineering application standpoint, Strain-Engineered MOSFETs introduces promising strain techniques to fabricate strain-engineered MOSFETs and to methods to assess the applications of these techniques. The book provides the background and physical insight needed to understand new and future developments in the modeling and design of n- and p-MOSFETs at nanoscale. This book focuses on recent developments in st
The Prediction of Maximum Amplitudes of Solar Cycles and the Maximum Amplitude of Solar Cycle 24
无
2002-01-01
We present a brief review of predictions of solar cycle maximum ampli-tude with a lead time of 2 years or more. It is pointed out that a precise predictionof the maximum amplitude with such a lead-time is still an open question despiteprogress made since the 1960s. A method of prediction using statistical character-istics of solar cycles is developed: the solar cycles are divided into two groups, ahigh rising velocity (HRV) group and a low rising velocity (LRV) group, dependingon the rising velocity in the ascending phase for a given duration of the ascendingphase. The amplitude of Solar Cycle 24 can be predicted after the start of thecycle using the formula derived in this paper. Now, about 5 years before the startof the cycle, we can make a preliminary prediction of 83.2-119.4 for its maximumamplitude.
Strain-induced negative differential resistance in ultrasmall carbon nanotube
Fang, Hui; Zhang, Fei-Peng; Ruan, Xing-Xiang; Huang, Can-Sheng; Jiang, Zhi-Nian; Peng, Jin-Yun; Wang, Ru-Zhi
2017-08-01
The transport properties in ultrasmall single-wall carbon nanotubes (SWCNTs) under tensile strain have been theoretically investigated. The regular negative differential resistance (NDR) induced by the strain undergoes a process from enhancement to weakening in the zigzag (3,0) SWCNT. The NDR achieves maximum with applying 4% tensile strain. Compared to the case of (3,0) SWCNT, that NDR cannot be manipulated by applying strain clearly in (4,0) and (5,0) ultrasmall SWCNTs with tensile strain lower than 10%. It proposes this strain-induced NDR effect to demonstrate the possibility of finding potential applications in SWCNT-based NDR nanodevices such as in memory devices, oscillators and fast switching devices.
Liou, Peng; Shan, Houxiang; Liu, Fu; Guo, Jinghui
2017-03-01
fractional crystallization of basaltic andesites (high-Al basalts) and andesites. Mixing of magmas at various stages along the fractionation course of basaltic andesites (high-Al basalts) toward rhyolites promotes the trend of the calc-alkaline series. To reconcile the 2.55 to 2.5 Ga TTGs derived from overthickened crust, the 2.51 to 2.50 Ga calc-alkaline volcanic rocks derived from thickened crust, tholeiitic basalts representing low pressure and an extensional tectonic setting, 2493 Ma leucosyenogranites derived from overthickened crust, 2437 Ma biotite-monzogranites derived from slightly thinner crust than leucosyenogranites but still thickened, as well as the clockwise hybrid ITD and IBC P-T paths of the HP granulites and widespread extension and rifting setting within the NCC from 2300 Ma, we propose a model of an evolving subduction process. Among them, the composition of the 2.5 Ga Changyukou volcanic rocks and potassic granites as well as the clockwise hybrid ITD and IBC P-T paths of the HP granulites may reveal that the tectonic setting in Northwest Hebei was in a transition stage from a subduction-related compressional regime to an extensional regime related to plate rollback.
Nomikou, P.; Hübscher, C.; Ruhnau, M.; Bejelou, K.
2016-03-01
The structural evolution of the South Aegean Sea is little explored due to the lack of marine seismic data. Our present day understanding is mainly based on some island outcrops and GPS measurements. In this study we discuss the rather incremental opening of the Anydros Basin in the Pliocene during six major tectonic pulses and the subsequent basin fill processes by interpreting seismic data and derived time isochore maps. Between the active pulses basin floor tilting persisted on a much lower rate. Seismic data illustrate the depositional processes in the emerging Anydros Basin. The observation of onlap fill strata, divergent reflection pattern, moat channels and contourite drifts imply that deposition was controlled by turbidity and contour currents as well as the tilting basin floor. The metamorphic Attico-Cycladic basement shows a rise that aligns along an NW-SE directed axis crossing Anydros island. This axis marks a structural change of the Santorini-Amorgos Ridge and thus represents a major structural boundary. Dip angles of NE-SW trending major faults, like the Santorini-Amorgos Fault, indicate normal faulting to be the superior mechanism forming the present horst and graben environment. Hence, the area is likely to be in a state of NW-SE directed extensional stresses forming the asymmetric graben structure of Anydros. Secondary fault clusters strike the same direction but show much steeper dip angles, possibly indicating strike-slip movement or resulting from deformational stresses along the hinge zones of the normal faults. The majority of the faults we discovered are located in the area of earthquake clusters, which is another indication of recent faulting. Ring faults around Kolumbo submarine volcano, result from caldera collapse and mark the diameter of the magma chamber approximately to 20 km.
Schneiderwind, S.; Boulton, S. J.; Papanikolaou, I.; Reicherter, K.
2017-04-01
useful for the identification of palaeo-shorelines in extensional tectonic environments where coseismic footwall uplift (only 1/2 to 1/4 of net slip per event) is unlikely to raise an entire notch above the tidal range.
Picazo, S.; Müntener, O.; Manatschal, G.; Bauville, A.; Karner, G.; Johnson, C.
2016-12-01
Systematic differences in mineral composition of mantle peridotites are observed in ophiolites and peridotitic bodies from the Alpine Tethys, the Pyrenean domain, the Dinarides and Hellenides, and the Iberia-Newfoundland rifted margins. These differences can be understood in the context of the evolution of rifted margins and allow the identification of 3 major mantle domains: an inherited domain, a refertilized domain and a depleted domain. Most clinopyroxene from the inherited domain equilibrated in the spinel peridotite field and are too enriched in Na2O and Al2O3 to be residues of syn-rift melting. Clinopyroxene from the refertilized domain partially equilibrated with plagioclase and display lower Na2O and Al2O3, and elevated Cr2O3 contents. The refertilized domain is a hybrid zone, which locally preserves remnants from the inherited domain and overlapping chemical compositions. Depleted domains with clinopyroxene similar to abyssal peridotites are rare and Nd-isotopic studies indicate that they represent ancient periods of melting unrelated to the opening of the Jurassic and Cretaceous oceanic basins of the Alpine Tethys and southern North Atlantic. In many studied sections of mantle rocks in exposed ophiolites a systematic spatial distribution of the different domains with respect to the evolution of rifted margins can be identified. This new approach integrates observations from exposed and drilled mantle rocks and proposes that the mantle lithosphere evolved and was modified during an extensional cycle from post-orogenic collapse through several periods of rifting to seafloor spreading. The defined chemical and petrological characteristics of mantle domains based on clinopyroxene and spinel compositions are compiled on present-day and paleogeographic maps of Western and Central Europe. These maps show that the observed distribution of mantle domains are linked to processes related to late post-Variscan extension, rift evolution and refertilization associated
... and chronic. An acute strain occurs when a muscle becomes strained or pulled — or may even tear — when it stretches unusually far or abruptly. Acute ... and increases joint range of motion, making the muscles less tight and less prone to trauma ... Environmental conditions. Slippery or uneven surfaces can make ...
Highly Strained Organophosphorus Compounds
Slootweg, J.C.
2005-01-01
In our research on small, strained organophosphorus ring systems we became interested in the synthesis and applications of species that are even more strained than the parent phosphirane, by introducing an exocyclic double bond (methylenephosphirane), and by cyclopropyl spirofusion to the edge (e.g
Pattern formation, logistics, and maximum path probability
Kirkaldy, J. S.
1985-05-01
The concept of pattern formation, which to current researchers is a synonym for self-organization, carries the connotation of deductive logic together with the process of spontaneous inference. Defining a pattern as an equivalence relation on a set of thermodynamic objects, we establish that a large class of irreversible pattern-forming systems, evolving along idealized quasisteady paths, approaches the stable steady state as a mapping upon the formal deductive imperatives of a propositional function calculus. In the preamble the classical reversible thermodynamics of composite systems is analyzed as an externally manipulated system of space partitioning and classification based on ideal enclosures and diaphragms. The diaphragms have discrete classification capabilities which are designated in relation to conserved quantities by descriptors such as impervious, diathermal, and adiabatic. Differentiability in the continuum thermodynamic calculus is invoked as equivalent to analyticity and consistency in the underlying class or sentential calculus. The seat of inference, however, rests with the thermodynamicist. In the transition to an irreversible pattern-forming system the defined nature of the composite reservoirs remains, but a given diaphragm is replaced by a pattern-forming system which by its nature is a spontaneously evolving volume partitioner and classifier of invariants. The seat of volition or inference for the classification system is thus transferred from the experimenter or theoretician to the diaphragm, and with it the full deductive facility. The equivalence relations or partitions associated with the emerging patterns may thus be associated with theorems of the natural pattern-forming calculus. The entropy function, together with its derivatives, is the vehicle which relates the logistics of reservoirs and diaphragms to the analog logistics of the continuum. Maximum path probability or second-order differentiability of the entropy in isolation are
Sreenivasulu Tadakaluru; Wiradej Thongsuwan; Pisith Singjai
2014-01-01
Conventional metallic strain sensors are flexible, but they can sustain maximum strains of only ∼5%, so there is a need for sensors that can bear high strains for multifunctional applications. In this study, we report stretchable and flexible high-strain sensors that consist of entangled and randomly distributed multiwall carbon nanotubes or graphite flakes on a natural rubber substrate. Carbon nanotubes/graphite flakes were sandwiched in natural rubber to produce these high-strain sensors. U...
Evaluation of strain levels in the IFSF rack
Richins, W.D.; Miller, G.K.
1997-06-01
An evaluation has been performed on strain levels determined for the IFSF fuel storage rack for seismic loading. The storage rack had been previously analyzed by a consulting company, Advanced Engineering Consultants (AEC), who reported significant strain levels in several members of the rack. The purpose for the study conducted herein was to refine the method for calculating strain levels, and then to assess the acceptability of the refined strain values. This was accomplished by making a modification to AEC`s model to more realistically represent plastic behavior in all locations where material yields. An analysis was performed where this modified model was subjected to the same seismic loadings as applied in AEC`s analysis. It was expected that the more realistic representation of plastic behavior in the modified model would result in reduced maximum calculated strains for the rack. Results of the analysis showed that the more realistic representation of plastic behavior in rack members did reduce the calculated maximum strains from those reported by AEC. These modified strains were evaluated for acceptability according to ductility criteria of the governing standard (i.e. ANSI/AISC N690-1994, as specified by the project Criteria Application Document). This evaluation showed that the strains meet these acceptance criteria. The analysis described herein was performed only to investigate this issue. AEC`s analysis stands as the analysis of record for the rack.
Strain y strain rate para dummies Strain and strain rate for dummies
Pastor Olaya
2011-12-01
Full Text Available Desarrollos recientes en el campo de la ecocardiografía han permitido a los cardiólogos cuantificar de manera objetiva la función miocárdica regional y global con base en los conceptos de deformación (strain y velocidad de deformación (strain rate que pueden calcularse de manera no invasiva tanto en el ventrículo izquierdo como en el derecho, y suministrar valiosa información en múltiples escenarios clínicos. Dado que esta técnica novedosa y promisoria se utiliza cada vez más en la clínica y en estudios de investigación, se hace necesario el conocimiento adecuado de sus principios, así como de sus aspectos técnicos, alcances y limitaciones para una mejor implementación. En este artículo se busca dar explicación a los conceptos fundamentales y las potenciales aplicaciones clínicas de la strain y la strain rate derivados por speckle tracking (strain 2D.Recent developments in the field of echocardiography have allowed cardiologists to objectively quantify regional and global myocardial function based on the deformation (strain and strain rate which can be calculated non-invasively in both the left or right ventricle, and provide valuable information in multiple clinical settings. Since this new technique is promising and is being increasingly used in clinical and research studies, the adequate knowledge of its principles and its technical aspects, scope and limitations are necessary for its better implementation. This article seeks to explain fundamental concepts and potential clinical applications of strain and strain rate derived by speckle tracking (2D strain.
Cardiorespiratory Fitness of Inmates of a Maximum Security Prison ...
USER
Maximum Security Prison; and also to determine the effects of age, gender, and period of incarceration on CRF. A total of 247 apparently healthy inmates of Maiduguri Maximum Security ... with different types of cardiovascular and metabolic.
Maximum likelihood polynomial regression for robust speech recognition
LU Yong; WU Zhenyang
2011-01-01
The linear hypothesis is the main disadvantage of maximum likelihood linear re- gression （MLLR）. This paper applies the polynomial regression method to model adaptation and establishes a nonlinear model adaptation algorithm using maximum likelihood polyno
Evandro Watanabe
2008-08-01
Full Text Available The aim of this in vitro study was to determine the maximum inhibitory dilution (MID of four cetylpyridinium chloride (CPC-based mouthwashes: CPC+Propolis, CPC+Malva, CPC+Eucaliptol+Juá+Romã+Propolis (Natural Honey® and CPC (Cepacol®, against 28 Staphylococcus aureus field strains, using the agar dilution method. Decimal dilutions ranging from 1/10 to 1/655,360 were prepared and added to Mueller Hinton Agar. Strains were inoculated using Steers multipoint inoculator. The inocula were seeded onto the surface of the culture medium in Petri dishes containing different dilutions of the mouthwashes. The dishes were incubated at 37ºC for 24 h. For readings, the MID was considered as the maximum dilution of mouthwash still capable of inhibiting microbial growth. The obtained data showed that CPC+Propolis had antimicrobial activity against 27 strains at 1/320 dilution and against all 28 strains at 1/160 dilution, CPC+Malva inhibited the growth of all 28 strains at 1/320 dilution, CPC+Eucaliptol+Juá+Romã+Propolis inhibited the growth of 2 strains at 1/640 dilution and all 28 strains at 1/320 dilution, and Cepacol® showed antimicrobial activity against 3 strains at 1/320 dilution and against all 28 strains at 1/160 dilution. Data were submitted to Kruskal-Wallis test, showing that the MID of Cepacol® was lower than that determined for the other products (p<0.05. In conclusion, CPC-mouthwashes showed antimicrobial activity against S. aureus and the addition of other substances to CPC improved its antimicrobial effect.
Capacitive Extensometer Particularly Suited for Measuring in Vivo Bone Strain
Perusek, Gail P. (Inventor)
2000-01-01
The present invention provides for in vivo measurements of the principal strain magnitudes and directions, and maximum shear strain that occurs in a material, such as human bone, when it is loaded (or subjected to a load). In one embodiment the invention includes a capacitive delta extensometer arranged with six sensors in a three piece configuration, with each sensor of each pair spaced apart from each other by 120 degrees.
M. Mihelich
2014-11-01
Full Text Available We derive rigorous results on the link between the principle of maximum entropy production and the principle of maximum Kolmogorov–Sinai entropy using a Markov model of the passive scalar diffusion called the Zero Range Process. We show analytically that both the entropy production and the Kolmogorov–Sinai entropy seen as functions of f admit a unique maximum denoted fmaxEP and fmaxKS. The behavior of these two maxima is explored as a function of the system disequilibrium and the system resolution N. The main result of this article is that fmaxEP and fmaxKS have the same Taylor expansion at first order in the deviation of equilibrium. We find that fmaxEP hardly depends on N whereas fmaxKS depends strongly on N. In particular, for a fixed difference of potential between the reservoirs, fmaxEP(N tends towards a non-zero value, while fmaxKS(N tends to 0 when N goes to infinity. For values of N typical of that adopted by Paltridge and climatologists (N ≈ 10 ~ 100, we show that fmaxEP and fmaxKS coincide even far from equilibrium. Finally, we show that one can find an optimal resolution N* such that fmaxEP and fmaxKS coincide, at least up to a second order parameter proportional to the non-equilibrium fluxes imposed to the boundaries. We find that the optimal resolution N* depends on the non equilibrium fluxes, so that deeper convection should be represented on finer grids. This result points to the inadequacy of using a single grid for representing convection in climate and weather models. Moreover, the application of this principle to passive scalar transport parametrization is therefore expected to provide both the value of the optimal flux, and of the optimal number of degrees of freedom (resolution to describe the system.
20 CFR 617.14 - Maximum amount of TRA.
2010-04-01
... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Maximum amount of TRA. 617.14 Section 617.14... FOR WORKERS UNDER THE TRADE ACT OF 1974 Trade Readjustment Allowances (TRA) § 617.14 Maximum amount of TRA. (a) General rule. Except as provided under paragraph (b) of this section, the maximum amount of...
40 CFR 94.107 - Determination of maximum test speed.
2010-07-01
... specified in 40 CFR 1065.510. These data points form the lug curve. It is not necessary to generate the... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Determination of maximum test speed... Determination of maximum test speed. (a) Overview. This section specifies how to determine maximum test...
14 CFR 25.1505 - Maximum operating limit speed.
2010-01-01
... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum operating limit speed. 25.1505... Operating Limitations § 25.1505 Maximum operating limit speed. The maximum operating limit speed (V MO/M MO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not...
Maximum Performance Tests in Children with Developmental Spastic Dysarthria.
Wit, J.; And Others
1993-01-01
Three Maximum Performance Tasks (Maximum Sound Prolongation, Fundamental Frequency Range, and Maximum Repetition Rate) were administered to 11 children (ages 6-11) with spastic dysarthria resulting from cerebral palsy and 11 controls. Despite intrasubject and intersubject variability in normal and pathological speakers, the tasks were found to be…
Maximum physical capacity testing in cancer patients undergoing chemotherapy
Knutsen, L.; Quist, M; Midtgaard, J
2006-01-01
BACKGROUND: Over the past few years there has been a growing interest in the field of physical exercise in rehabilitation of cancer patients, leading to requirements for objective maximum physical capacity measurement (maximum oxygen uptake (VO(2max)) and one-repetition maximum (1RM)) to determine...
Extensional structures in anisotropic rocks
Platt, J.P.; Vissers, R.L.M.
1980-01-01
A distinct class of structures can form as a result of extension along a plane of anisotropy (foliation). The effect of the foliation is to decrease the ductility of the material in this orientation so that brittle fractures or shear-bands develop. Foliation boudinage is caused by brittle failure; e
Berry, Vincent; Nicolas, François
2006-01-01
Given a set of evolutionary trees on a same set of taxa, the maximum agreement subtree problem (MAST), respectively, maximum compatible tree problem (MCT), consists of finding a largest subset of taxa such that all input trees restricted to these taxa are isomorphic, respectively compatible. These problems have several applications in phylogenetics such as the computation of a consensus of phylogenies obtained from different data sets, the identification of species subjected to horizontal gene transfers and, more recently, the inference of supertrees, e.g., Trees Of Life. We provide two linear time algorithms to check the isomorphism, respectively, compatibility, of a set of trees or otherwise identify a conflict between the trees with respect to the relative location of a small subset of taxa. Then, we use these algorithms as subroutines to solve MAST and MCT on rooted or unrooted trees of unbounded degree. More precisely, we give exact fixed-parameter tractable algorithms, whose running time is uniformly polynomial when the number of taxa on which the trees disagree is bounded. The improves on a known result for MAST and proves fixed-parameter tractability for MCT.
... Elsevier Saunders; 2015:chap 88. Reider B, Davies GJ, Provencher MT. Muscle strains about the hip and thigh. In: Reider B, Davies GJ, Provencher MT, eds. Orthopaedic Rehabilitation of the Athlete . ...
Tartaglia, Angelo
2015-01-01
Starting from some relevant facts concerning the behaviour of the universe over large scale and time span, the analogy between the geometric approach of General Relativ- ity and the classical description of an elastic strained material continuum is discussed. Extending the elastic deformation approach to four dimensions it is shown that the accelerated expansion of the universe is recovered. The strain field of space-time repro- duces properties similar to the ones ascribed to the dark energy currently called in to explain the accelerated expansion. The strain field in the primordial universe behaves as radiation, but asymptotically it reproduces the cosmological constant. Subjecting the theory to a number of cosmological tests confirms the soundness of the approach and gives an optimal value for the one parameter of the model, i.e. the bulk modulus of the space-time continuum. Finally various aspects of the Strained State Cosmology (SSC) are discussed and contrasted with some non-linear massive gravity theor...
Ji, Wenbin; Lin, Wei; Faure, Michel; Shi, Yonghong; Wang, Qingchen
2016-03-01
The Dabieshan massif is famous as a portion of the world's largest HP-UHP metamorphic belt in east-central China that was built by the Triassic North-South China collision. The central domain of the Dabieshan massif is occupied by a huge migmatite-cored dome [i.e., the central Dabieshan dome (CDD)]. Origin of this domal structure remains controversial. Synthesizing previous and our new structural and geochronological data, we define the Cretaceous Dabieshan as an orogen-scale metamorphic core complex (MCC) with a multistage history. Onset of lithospheric extension in the Dabieshan area occurred as early as the commencement of crustal anatexis at the earliest Cretaceous (ca. 145 Ma), which was followed by primary (early-stage) detachment during 142-130 Ma. The central Dabieshan complex in the footwall and surrounding detachment faults recorded a consistently top-to-the-NW shearing. It is thus inferred that the primary detachment was initiated from a flat-lying detachment zone at the middle crust level. Removal of the orogenic root by delamination at ca. 130 Ma came into the extensional climax, and subsequently isostatic rebound resulted in rapid doming. Along with exhumation of the footwall, the mid-crustal detachment zone had been warped as shear zones around the CDD. After 120 Ma, the detachment system probably experienced a migration accommodated to the crustal adjustment, which led to secondary (late-stage) detachment with localized ductile shearing at ca. 110 Ma. The migmatite-gneiss with HP/UHP relicts in the CDD (i.e., the central Dabieshan complex) was product of the Cretaceous crustal anatexis that consumed the deep-seated part of the HP-UHP slices and the underlying para-autochthonous basement. Compared with the contemporaneous MCCs widely developed along the eastern margin of the Eurasian continent, we proposed that occurrence of the Dabieshan MCC shares the same tectonic setting as the "destruction of the North China craton". However, geodynamic trigger
Ji, Wenbin; Lin, Wei; Faure, Michel; Shi, Yonghong; Wang, Qingchen
2017-06-01
The Dabieshan massif is famous as a portion of the world's largest HP-UHP metamorphic belt in east-central China that was built by the Triassic North-South China collision. The central domain of the Dabieshan massif is occupied by a huge migmatite-cored dome [i.e., the central Dabieshan dome (CDD)]. Origin of this domal structure remains controversial. Synthesizing previous and our new structural and geochronological data, we define the Cretaceous Dabieshan as an orogen-scale metamorphic core complex (MCC) with a multistage history. Onset of lithospheric extension in the Dabieshan area occurred as early as the commencement of crustal anatexis at the earliest Cretaceous (ca. 145 Ma), which was followed by primary (early-stage) detachment during 142-130 Ma. The central Dabieshan complex in the footwall and surrounding detachment faults recorded a consistently top-to-the-NW shearing. It is thus inferred that the primary detachment was initiated from a flat-lying detachment zone at the middle crust level. Removal of the orogenic root by delamination at ca. 130 Ma came into the extensional climax, and subsequently isostatic rebound resulted in rapid doming. Along with exhumation of the footwall, the mid-crustal detachment zone had been warped as shear zones around the CDD. After 120 Ma, the detachment system probably experienced a migration accommodated to the crustal adjustment, which led to secondary (late-stage) detachment with localized ductile shearing at ca. 110 Ma. The migmatite-gneiss with HP/UHP relicts in the CDD (i.e., the central Dabieshan complex) was product of the Cretaceous crustal anatexis that consumed the deep-seated part of the HP-UHP slices and the underlying para-autochthonous basement. Compared with the contemporaneous MCCs widely developed along the eastern margin of the Eurasian continent, we proposed that occurrence of the Dabieshan MCC shares the same tectonic setting as the "destruction of the North China craton". However, geodynamic trigger
Gori, Stefano; Falcucci, Emanuela; Ladina, Chiara; Marzorati, Simone; Galadini, Fabrizio
2017-03-01
legacy must be considered in a wider evolutionary perspective. Our results testify that a large-scale basin and range geomorphological feature - often adopted for morpho-tectonic and kinematic evaluations in active extensional contexts, as in the Apennines - just led by range-bounding active normal faults may be actually simplistic, as it could not be applied everywhere, owing to peculiar complexities of the local tectonic histories.
Rutherford, B. S.; Speece, M. A.; Stickney, M. C.; Mosolf, J. G.
2013-12-01
Reprocessing of one 24-fold (96 channel) and four 30-fold (120 channel) 2D seismic reflection profiles have revealed crustal scale reflections in the Swan Range and adjacent Swan River Valley of northwestern Montana. The five reprocessed profiles constitute 142.6 of the 303.3 linear km acquired in 1983-84 by Techo of Denver, Colorado. The four 30-fold profiles used helicopter-assisted dynamite shooting (Poulter method) and the 24-fold profile used the Vibroseis method. Acquisition parameters were state of the art for the time. The Swan Range lies east of the Rocky Mountain Trench and is part of the Cordilleran foreland thrust belt where the Lewis thrust system emplaced a thick slab of Proterozoic Belt Supergroup strata eastward and over Paleozoic and Mesozoic rocks during the Late Cretaceous to early Paleocene Laramide orogeny. Deeply drilled borehole data are absent within the study area; however, we generated a synthetic seismogram from the Arco-Marathon 1 Paul Gibbs well (total depth=5418 m), located approximately 70 km west of the reprocessed profiles, and correlated the well data to surface seismic profiles. Large impedance contrasts in the log data are interpreted to be tholeiitic Moyie sills within the Prichard Formation argillite (Lower Belt), which produce strong reflection events in regional seismic sections and result in highly reflective, east-dipping events in the reprocessed profiles. We estimate a depth of 10 km (3 to 3.5 seconds) to the basal detachment of the Lewis thrust sheet. The décollement lies within Belt Supergroup strata to the west of the Swan River Valley before contacting unreflective, west-dipping crystalline basement beneath the Swan Range--a geometry that results in a wedge of eastward-thinning, autochthonous Belt rocks. Distinct fault-plane signatures from the west-dipping, range-bounding Swan fault--produced by extensional collapse of the over-thickened Cordillera--are not successfully imaged. However, reflections from Cenozoic
Psychological strain between nurses
Andrea Obročníková
2015-12-01
Full Text Available Aim: The aim of the study was to identify differences in perception of work (mental workload among nurses providing acute and chronic nursing care. Design: Study design is cross-sectional and descriptive. Methods: The sample of respondents consisted of 97 nurses working in departments Neurology, Anesthesiology and Intensive Care Unit of the hospital St. James in Bardejov, University Hospital of L. Pasteur in Košice and University Hospital J. A. Reiman in Prešov. To measure psychological strain, Meister's questionnaire for neuropsychological strain was used. Results: Increased psychological strain was observed in nurses providing acute care versus nurses providing chronic care, particularly in job satisfaction, long-term tolerance, time constraints, high responsibility, nervousness, fatigue and satiety. In comparison with the population norm, nurses in acute care achieved significantly higher indicators of factor I (strain and gross score as nurses in neurological care. A statistically significant relationship between psychological stress and age of nurses working in anesthesiology and intensive care departments was confirmed. Nurses with long term practical experience are exposed to intense mental stress (especially in the areas of strain and monotony. Conclusion: The results of our study suggest the reality that variable qualities of work related strain among nurses can lead to physical and emotional exhaustion.
Choi, Changhoon; Ahn, Joongho; Jeon, Seungwan; Kim, Chulhong
2017-07-01
Vulnerable plaques are the major cause of cardiovascular disease, but they are difficult to detect with conventional intravascular imaging techniques. Techniques are needed to identify plaque vulnerability based on the presence of lipids in plaque. Thermal strain imaging (TSI) is an imaging technique based on ultrasound (US) wave propagation speed, which varies with the medium temperature. In TSI, the strain that occurs during tissue temperature change can be used for lipid detection because it has a different tendency depending on the type of tissue. Here, we demonstrate photothermal strain imaging (pTSI) using an intravascular ultrasound catheter. pTSI is performed by slightly and selectively heating lipid using a relatively inexpensive continuous laser source. We applied a speckle-tracking algorithm to US B-mode images for strain calculations. As a result, the strain produced in porcine fat was different from the strain produced in water-bearing gelatin phantom, which made it possible to distinguish the two. This suggests that pTSI could potentially be a way of differentiating lipids in coronary artery.
Present and Last Glacial Maximum climates as states of maximum entropy production
Herbert, Corentin; Kageyama, Masa; Dubrulle, Berengere
2011-01-01
The Earth, like other planets with a relatively thick atmosphere, is not locally in radiative equilibrium and the transport of energy by the geophysical fluids (atmosphere and ocean) plays a fundamental role in determining its climate. Using simple energy-balance models, it was suggested a few decades ago that the meridional energy fluxes might follow a thermodynamic Maximum Entropy Production (MEP) principle. In the present study, we assess the MEP hypothesis in the framework of a minimal climate model based solely on a robust radiative scheme and the MEP principle, with no extra assumptions. Specifically, we show that by choosing an adequate radiative exchange formulation, the Net Exchange Formulation, a rigorous derivation of all the physical parameters can be performed. The MEP principle is also extended to surface energy fluxes, in addition to meridional energy fluxes. The climate model presented here is extremely fast, needs very little empirical data and does not rely on ad hoc parameterizations. We in...
Strain engineering of WS2, WSe2, and WTe2
Amin, Bin
2014-01-01
We perform first-principles calculations to investigate the structural, electronic, and vibrational properties of WS2, WSe2, and WTe2 monolayers, taking into account the strong spin orbit coupling. A transition from a direct to an indirect band gap is achieved for compressive strain of 1% for WS2, 1.5% for WSe2, and 2% for WTe 2, while the nature of the band gap remains direct in the case of tensile strain. The size of the band gap passes through a maximum under compressive strain and decreases monotonically under tensile strain. A strong spin splitting is found for the valence band in all three compounds, which is further enhanced by tensile strain. The mobility of the electrons grows along the series WS2 < WSe2 < WTe2. This journal is © the Partner Organisations 2014.
Standard practice for strain controlled thermomechanical fatigue testing
American Society for Testing and Materials. Philadelphia
2010-01-01
1.1 This practice covers the determination of thermomechanical fatigue (TMF) properties of materials under uniaxially loaded strain-controlled conditions. A “thermomechanical” fatigue cycle is here defined as a condition where uniform temperature and strain fields over the specimen gage section are simultaneously varied and independently controlled. This practice is intended to address TMF testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. While this practice is specific to strain-controlled testing, many sections will provide useful information for force-controlled or stress-controlled TMF testing. 1.2 This practice allows for any maximum and minimum values of temperature and mechanical strain, and temperature-mechanical strain phasing, with the restriction being that such parameters remain cyclically constant throughout the duration of the test. No restrictions are placed on en...
Heilbronner, Renée
2017-04-01
2017 marks the 50th anniversary of the publication of John Ramsay's well known textbook "Folding and Fracturing of Rocks" - ... and the 30th anniversary of the rejection of a rather less well known paper entitled "Strain: Fact or Fiction?" submitted by Renée Panozzo to the Journal of Structural Geology. The gist of the paper was simple and straight forward: it was argued that not every fabric that can be observed in deformed rocks is necessarily a measure of the amount of strain the rock incurred. A distinction was made between a general "fabric", i.e., the traceable geometry of grain boundaries, for example, and a so-called "strain fabric", i.e., the model geometry that would result from homogeneously straining an initially isotropic fabric and that would exhibit at least orthorhombic symmetry. To verify if a given fabric was indeed a strain fabric it was therefore suggested to use the SURFOR method (published by Panozzo) and to carry out a so-called strain test, i.e., a check of symmetry, before interpreting the results of a fabric analysis in terms of strain. The problem with the paper was that it was very obviously written out of frustration. The frustration came form having reviewed a number of manuscripts which tried to use the then novel SURFOR method for strain analysis without first checking if the the fabric was a indeed a "strain fabric" or not, and then blaming the SURFOR method for producing ambiguous results. As a result, the paper was not exactly well balanced and carefully thought out. It was considered "interesting but not scholarly" by one of the reviewers and down-right offensive by the second. To tell the truth, however, the paper was not formally rejected. The editor Sue Treagus strongly encouraged Panozzo to revise the paper, ... and 30 years later, I will follow her advise and offer a revised paper as a tribute to John Ramsay. To quote from the original manuscript: "We should be a little more impressed that strain works so well, and less
Ketner, Keith Brindley; Day, Warren C.; Elrick, Maya; Vaag, Myra K.; Zimmerman, Robert A.; Snee, Lawrence W.; Saltus, Richard W.; Repetski, John E.; Wardlaw, Bruce R.; Taylor, Michael E.; Harris, Anita G.
1998-01-01
Seven kinds of fault-bounded tracts are described. One of the tracts provides a good example of Mesozoic contractional folding and faulting; six exemplify various aspects of Miocene extensional faulting. Massive landslide deposits resulting from Tertiary faulting are described. Mesozoic intrusive rocks and extensive exposures of Miocene volcanic rocks are described and dated. The age ranges of stratigraphic units were based on numerous conodont collections, and ages of igneous rocks were determined by argon/argon and fission-track methods. The geologic complexity of the Goshute-Toano Range provides opportunities for many additional productive structural studies.
Study of dynamic strain aging in dual phase steel
Queiroz, R.R.U. [Instituto Federal de Minas Gerais. Rua Pandia Calogeras, 898, Bauxita, Ouro Preto, MG (Brazil); Cunha, F.G.G. [Department of Metallurgical and Materials Engineering, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, Pampulha, Belo Horizonte, MG (Brazil); Gonzalez, B.M., E-mail: gonzalez@demet.ufmg.br [Department of Metallurgical and Materials Engineering, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, Pampulha, Belo Horizonte, MG (Brazil)
2012-05-01
Highlights: Black-Right-Pointing-Pointer Characterization of the high temperature mechanical behavior of a dual phase steel. Black-Right-Pointing-Pointer Determination of the effect of dynamic strain aging on the strain hardening rate. Black-Right-Pointing-Pointer Identification of the mechanism associated with dynamic strain aging. Black-Right-Pointing-Pointer The value of the interaction energy carbon-dislocation in ferrite was confirmed. - Abstract: The susceptibility to dynamic strain aging of a dual phase steel was evaluated by the variation of mechanical properties in tension with the temperature and the strain rate. The tensile tests were performed at temperatures varying between 25 Degree-Sign C and 600 Degree-Sign C and at strain rates ranging from 10{sup -2} to 5 Multiplication-Sign 10{sup -4} s{sup -1}. The studied steel presented typical manifestations related to dynamic strain aging: serrated flow (the Portevin-Le Chatelier effect) for certain combinations of temperature and strain rates; the presence of a plateau in the variation of yield stress with temperature; a maximum in the curves of tensile strength, flow stress, and work hardening exponent as a function of temperature; and a minimum in the variation of total elongation with temperature. The determined apparent activation energy values, associated with the beginning of the Portevin-Le Chatelier effect and the maximum in the variation of flow stress with temperature, were 83 kJ/mol and 156 kJ/mol, respectively. These values suggest that the mechanism responsible for dynamic strain aging in the dual phase steel is the locking of dislocations by carbon atoms in ferrite and that the formation of clusters and/or transition carbides and carbide precipitation in martensite do not interfere with the dynamic strain aging process.
A Note on k-Limited Maximum Base
Yang Ruishun; Yang Xiaowei
2006-01-01
The problem of k-limited maximum base was specified into two special problems of k-limited maximum base; that is, let subset D of the problem of k-limited maximum base be an independent set and a circuit of the matroid, respectively. It was proved that under this circumstance the collections of k-limited base satisfy base axioms. Then a new matroid was determined, and the problem of k-limited maximum base was transformed to the problem of maximum base of this new matroid. Aiming at the problem, two algorithms, which in essence are greedy algorithms based on former matroid, were presented for the two special problems of k-limited maximum base. They were proved to be reasonable and more efficient than the algorithm presented by Ma Zhongfan in view of the complexity of algorithm.
An Interval Maximum Entropy Method for Quadratic Programming Problem
RUI Wen-juan; CAO De-xin; SONG Xie-wu
2005-01-01
With the idea of maximum entropy function and penalty function methods, we transform the quadratic programming problem into an unconstrained differentiable optimization problem, discuss the interval extension of the maximum entropy function, provide the region deletion test rules and design an interval maximum entropy algorithm for quadratic programming problem. The convergence of the method is proved and numerical results are presented. Both theoretical and numerical results show that the method is reliable and efficient.
Hutchinson, Thomas H. [Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH (United Kingdom)], E-mail: thom1@pml.ac.uk; Boegi, Christian [BASF SE, Product Safety, GUP/PA, Z470, 67056 Ludwigshafen (Germany); Winter, Matthew J. [AstraZeneca Safety, Health and Environment, Brixham Environmental Laboratory, Devon TQ5 8BA (United Kingdom); Owens, J. Willie [The Procter and Gamble Company, Central Product Safety, 11810 East Miami River Road, Cincinnati, OH 45252 (United States)
2009-02-19
There is increasing recognition of the need to identify specific sublethal effects of chemicals, such as reproductive toxicity, and specific modes of actions of the chemicals, such as interference with the endocrine system. To achieve these aims requires criteria which provide a basis to interpret study findings so as to separate these specific toxicities and modes of action from not only acute lethality per se but also from severe inanition and malaise that non-specifically compromise reproductive capacity and the response of endocrine endpoints. Mammalian toxicologists have recognized that very high dose levels are sometimes required to elicit both specific adverse effects and present the potential of non-specific 'systemic toxicity'. Mammalian toxicologists have developed the concept of a maximum tolerated dose (MTD) beyond which a specific toxicity or action cannot be attributed to a test substance due to the compromised state of the organism. Ecotoxicologists are now confronted by a similar challenge and must develop an analogous concept of a MTD and the respective criteria. As examples of this conundrum, we note recent developments in efforts to validate protocols for fish reproductive toxicity and endocrine screens (e.g. some chemicals originally selected as 'negatives' elicited decreases in fecundity or changes in endpoints intended to be biomarkers for endocrine modes of action). Unless analogous criteria can be developed, the potentially confounding effects of systemic toxicity may then undermine the reliable assessment of specific reproductive effects or biomarkers such as vitellogenin or spiggin. The same issue confronts other areas of aquatic toxicology (e.g., genotoxicity) and the use of aquatic animals for preclinical assessments of drugs (e.g., use of zebrafish for drug safety assessment). We propose that there are benefits to adopting the concept of an MTD for toxicology and pharmacology studies using fish and other aquatic
Integer Programming Model for Maximum Clique in Graph
YUAN Xi-bo; YANG You; ZENG Xin-hai
2005-01-01
The maximum clique or maximum independent set of graph is a classical problem in graph theory. Combined with Boolean algebra and integer programming, two integer programming models for maximum clique problem,which improve the old results were designed in this paper. Then, the programming model for maximum independent set is a corollary of the main results. These two models can be easily applied to computer algorithm and software, and suitable for graphs of any scale. Finally the models are presented as Lingo algorithms, verified and compared by several examples.
Counterexamples to convergence theorem of maximum-entropy clustering algorithm
于剑; 石洪波; 黄厚宽; 孙喜晨; 程乾生
2003-01-01
In this paper, we surveyed the development of maximum-entropy clustering algorithm, pointed out that the maximum-entropy clustering algorithm is not new in essence, and constructed two examples to show that the iterative sequence given by the maximum-entropy clustering algorithm may not converge to a local minimum of its objective function, but a saddle point. Based on these results, our paper shows that the convergence theorem of maximum-entropy clustering algorithm put forward by Kenneth Rose et al. does not hold in general cases.
Towards Understanding Fatigue Disbond Growth via Cyclic Strain Energy
Pascoe, J.A.; Alderliesten, R.C.; Benedictus, R.
2014-01-01
The concept of relating fatigue disbond growth to the strain energy release rate (SERR) is critically examined. It is highlighted that the common practise of using only the maximum SERR or only the SERR range is insufficient to correctly characterize a load cycle. As crack growth requires energy, it
Transfer induced compressive strain in graphene
Larsen, Martin Benjamin Barbour Spanget; Mackenzie, David; Caridad, Jose
2014-01-01
We have used spatially resolved micro Raman spectroscopy to map the full width at half maximum (FWHM) of the graphene G-band and the 2D and G peak positions, for as-grown graphene on copper catalyst layers, for transferred CVD graphene and for micromechanically exfoliated graphene, in order...... to characterize the effects of a transfer process on graphene properties. Here we use the FWHM(G) as an indicator of the doping level of graphene, and the ratio of the shifts in the 2D and G bands as an indicator of strain. We find that the transfer process introduces an isotropic, spatially uniform, compressive...... strain in graphene, and increases the carrier concentration....
A novel limiting strain energy strength theory
LIU Guang-lian
2009-01-01
With applied dislocation theory,the effects of shear and normal stresses on the slide and climb motions at the same section of a crystal were analyzed.And,based on the synergetic effect of both normal and shear strain specific energies,the concept of the total equivalent strain specific energy (TESSE) at an oblique section and a new strength theory named as limiting strain energy strength theory (LSEST) were proposed.As for isotropic materials,the plastic yielding or brittle fracture of under uniaxial stress state would occur when the maximum TESSE reached the strain specific energy,also the expressions on the equivalent stresses and a function of failure of the LSEST under different principal stress states were obtained.Relationship formulas among the tensile,compressive and shear yield strengths for plastic metals were derived.These theoretical predictions,according to the LSEST,were consistent very well with experiment results of tensile,compressive and torsion tests of three plastic metals and other experiment results from open literatures.This novel LSEST might also help for strength calculation of other materials.
High strain rate behaviour of polypropylene microfoams
Gómez-del Río, T.; Garrido, M. A.; Rodríguez, J.; Arencón, D.; Martínez, A. B.
2012-08-01
Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc.) or personal safety (helmets, knee-pads, etc.). In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry) is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000 s-1) in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB). Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.
High strain rate behaviour of polypropylene microfoams
Martínez A.B.
2012-08-01
Full Text Available Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc. or personal safety (helmets, knee-pads, etc.. In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000 s−1 in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB. Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.
Mang, H A; Jia, X
2013-08-01
It is shown that the determinant of the tangent stiffness matrix has a maximum in the prebuckling regime if and only if the determinant of a specific linear combination of the first and the third derivative of this matrix with respect to a dimensionless load factor vanishes. The mathematical tool for this proof is the so-called consistently linearized eigenproblem in the frame of the Finite Element Method. The physical meaning of the mentioned maximum is the one of a minimum of the percentage bending energy of the total strain energy. The paper provides mathematical and physical background knowledge on numerical results that were obtained 35 years ago.
Tectónica extensional triásica en el sector norte de la cuenca Cuyana: primeros datos cinemáticos
María S. Japas
2008-06-01
Full Text Available En el ámbito precordillerano, las sucesiones clásticas y volcánicas que rellenan el rift triásico de la cuenca Cuyana han sido afectadas por la tectónica contraccional y transpresiva andina. En la Precordillera Sur, la deformación neógena sobreimpuesta a las estructuras extensionales que formaron la cuenca condujo a la inversión tectónica de los hemigrábenes y al ascenso y desmembramiento del relleno, configurando afloramientos aislados cuya distribución presenta un neto control tectónico. El grado de inversión tectónica y la complejidad de la deformación neógena varía en los distintos sectores de la cuenca. A escala regional, tales variaciones en el estilo estructural andino están fuertemente influenciadas por la presencia de anisotropías oblicuas de primer orden, como los bordes de la cuenca Cuyana o extensas fajas de cizalla sanrafaélicas. Por ello, el estudio de la cinemática extensional triásica se ha iniciado en el sector central de la Precordillera Sur, sobre la lámina de corrimiento Cerro Manantial, en el cordón San Bartolo, donde los efectos de la inversión tectónica son menos severos y la influencia de la cizalla simple ejercida por las anisotropías oblicuas es menor. En la sucesión de estratos de la Formación Cielo del Grupo Uspallata, que aflora en ambas márgenes de la quebrada El Salto, se reconocen cuatro juegos de fallas normales; el rechazo de los bancos por las fallas es del orden de decenas de centímetros a varios metros. Indicadores cinemáticos mesoscópicos como grietas escalonadas, cizallas de Riedel y fracturas sigmoidales se asocian a los planos de falla allí expuestos. Restando los efectos de la rotación neógena asociada a la falla Cerro Manantial, el análisis cinemático de esa población de estructuras frágiles indica una dirección de extensión NNE. Tomando en cuenta la orientación general al NNW (Az. 150º del tramo norte de la cuenca Cuyana y la dirección de extensión NNE (Az
Combining Experiments and Simulations Using the Maximum Entropy Principle
Boomsma, Wouter; Ferkinghoff-Borg, Jesper; Lindorff-Larsen, Kresten
2014-01-01
are not in quantitative agreement with experimental data. The principle of maximum entropy is a general procedure for constructing probability distributions in the light of new data, making it a natural tool in cases when an initial model provides results that are at odds with experiments. The number of maximum entropy...
49 CFR 174.86 - Maximum allowable operating speed.
2010-10-01
... 49 Transportation 2 2010-10-01 2010-10-01 false Maximum allowable operating speed. 174.86 Section... operating speed. (a) For molten metals and molten glass shipped in packagings other than those prescribed in § 173.247 of this subchapter, the maximum allowable operating speed may not exceed 24 km/hour (15...
Parametric optimization of thermoelectric elements footprint for maximum power generation
Rezania, A.; Rosendahl, Lasse; Yin, Hao
2014-01-01
The development studies in thermoelectric generator (TEG) systems are mostly disconnected to parametric optimization of the module components. In this study, optimum footprint ratio of n- and p-type thermoelectric (TE) elements is explored to achieve maximum power generation, maximum cost-perform...
30 CFR 56.19066 - Maximum riders in a conveyance.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maximum riders in a conveyance. 56.19066 Section 56.19066 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 56.19066 Maximum riders in a conveyance. In shafts inclined over 45...
30 CFR 57.19066 - Maximum riders in a conveyance.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maximum riders in a conveyance. 57.19066 Section 57.19066 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 57.19066 Maximum riders in a conveyance. In shafts inclined over 45...
Maximum Atmospheric Entry Angle for Specified Retrofire Impulse
T. N. Srivastava
1969-07-01
Full Text Available Maximum atmospheric entry angles for vehicles initially moving in elliptic orbits are investigated and it is shown that tangential retrofire impulse at the apogee results in the maximum entry angle. Equivalence of maximizing the entry angle and minimizing the retrofire impulse is also established.
5 CFR 838.711 - Maximum former spouse survivor annuity.
2010-01-01
... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Maximum former spouse survivor annuity... Orders Awarding Former Spouse Survivor Annuities Limitations on Survivor Annuities § 838.711 Maximum former spouse survivor annuity. (a) Under CSRS, payments under a court order may not exceed the...
46 CFR 151.45-6 - Maximum amount of cargo.
2010-10-01
... 46 Shipping 5 2010-10-01 2010-10-01 false Maximum amount of cargo. 151.45-6 Section 151.45-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Operations § 151.45-6 Maximum amount of cargo. (a)...
20 CFR 226.52 - Total annuity subject to maximum.
2010-04-01
... rate effective on the date the supplemental annuity begins, before any reduction for a private pension... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Total annuity subject to maximum. 226.52... COMPUTING EMPLOYEE, SPOUSE, AND DIVORCED SPOUSE ANNUITIES Railroad Retirement Family Maximum § 226.52...
49 CFR 195.406 - Maximum operating pressure.
2010-10-01
... 49 Transportation 3 2010-10-01 2010-10-01 false Maximum operating pressure. 195.406 Section 195... HAZARDOUS LIQUIDS BY PIPELINE Operation and Maintenance § 195.406 Maximum operating pressure. (a) Except for surge pressures and other variations from normal operations, no operator may operate a pipeline at a...
Maximum-entropy clustering algorithm and its global convergence analysis
无
2001-01-01
Constructing a batch of differentiable entropy functions touniformly approximate an objective function by means of the maximum-entropy principle, a new clustering algorithm, called maximum-entropy clustering algorithm, is proposed based on optimization theory. This algorithm is a soft generalization of the hard C-means algorithm and possesses global convergence. Its relations with other clustering algorithms are discussed.
Distribution of maximum loss of fractional Brownian motion with drift
Çağlar, Mine; Vardar-Acar, Ceren
2013-01-01
In this paper, we find bounds on the distribution of the maximum loss of fractional Brownian motion with H >= 1/2 and derive estimates on its tail probability. Asymptotically, the tail of the distribution of maximum loss over [0, t] behaves like the tail of the marginal distribution at time t.
48 CFR 436.575 - Maximum workweek-construction schedule.
2010-10-01
...-construction schedule. 436.575 Section 436.575 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE... Maximum workweek-construction schedule. The contracting officer shall insert the clause at 452.236-75, Maximum Workweek-Construction Schedule, if the clause at FAR 52.236-15 is used and the contractor's...
30 CFR 57.5039 - Maximum permissible concentration.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maximum permissible concentration. 57.5039... Maximum permissible concentration. Except as provided by standard § 57.5005, persons shall not be exposed to air containing concentrations of radon daughters exceeding 1.0 WL in active workings. ...
5 CFR 550.105 - Biweekly maximum earnings limitation.
2010-01-01
... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Biweekly maximum earnings limitation. 550.105 Section 550.105 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Premium Pay Maximum Earnings Limitations § 550.105 Biweekly...
5 CFR 550.106 - Annual maximum earnings limitation.
2010-01-01
... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Annual maximum earnings limitation. 550.106 Section 550.106 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Premium Pay Maximum Earnings Limitations § 550.106 Annual...
32 CFR 842.35 - Depreciation and maximum allowances.
2010-07-01
... 32 National Defense 6 2010-07-01 2010-07-01 false Depreciation and maximum allowances. 842.35... LITIGATION ADMINISTRATIVE CLAIMS Personnel Claims (31 U.S.C. 3701, 3721) § 842.35 Depreciation and maximum allowances. The military services have jointly established the “Allowance List-Depreciation Guide”...
张金福; 王思清
2013-01-01
With the continuous improvement of the status and role of the university scientific research team, it is particularly important to the construction of evaluation system on the academic productivity of university scientific research team. Based on the knowledge that talents cultivation output is the extensional academic productivity, this paper constructs the evaluation system of extensional productivity of scientific research teams by using multiple research methods.% 随着大学科研团队的地位和作用的不断提升，对大学科研团队学术产出的评价体系的构建尤为重要。本文围绕社会服务产出是大学科研团队的外延性学术产出的认识，运用多元研究方法，构建了大学科研团队的内蕴性学术产出的评价体系。
Incorporation of Mean/Maximum Stress Effects in the Multiaxial Racetrack Filter
Marco Antonio Meggiolaro
2016-10-01
Full Text Available This work extends the Multiaxial Racetrack Filter (MRF to incorporate mean or maximum stress effects, adopting a filter amplitude that depends on the current stress level along the stress or strain path. In this way, a small stress or strain amplitude event can be filtered out if associated with a non-damaging low mean or peak stress level, while another event with the very same amplitude can be preserved if happening under a more damaging high mean or peak stress level. The variable value of the filter amplitude must be calculated in real time, thus it cannot depend on the peak or mean stresses along a load event, because it would require cycle identification and as so information about future events. Instead, mean/maximum stress effects are modeled in the filter as a function of the current (instantaneous hydrostatic or normal stress along the multiaxial load path, respectively for invariantbased and critical-plane models. The MRF efficiency is evaluated from tension-torsion experiments in 316L stainless steel tubular specimens under non-proportional (NP load paths, showing it can robustly filter out nondamaging events even under multiaxial NP variable amplitude loading histories
Foulger, G.R.
1995-01-01
Given a uniform lithology and strain rate and a full seismic data set, the maximum depth of earthquakes may be viewed to a first order as an isotherm. These conditions are approached at the Hengill geothermal area, S. Iceland, a dominantly basaltic area. The temperature at which seismic failure ceases for the strain rates likely at the Hengill geothermal area is determined by analogy with oceanic crust, and is about 650 ?? 50??C. The topographies of the top and bottom of the seismogenic layer were mapped using 617 earthquakes. The thickness of the seismogenic layer is roughly constant and about 3 km. A shallow, aseismic, low-velocity volume within the spreading plate boundary that crosses the area occurs above the top of the seismogenic layer and is interpreted as an isolated body of partial melt. The base of the seismogenic layer has a maximum depth of about 6.5 km beneath the spreading axis and deepens to about 7 km beneath a transform zone in the south of the area. -from Author
Maximum Principles for Discrete and Semidiscrete Reaction-Diffusion Equation
Petr Stehlík
2015-01-01
Full Text Available We study reaction-diffusion equations with a general reaction function f on one-dimensional lattices with continuous or discrete time ux′ (or Δtux=k(ux-1-2ux+ux+1+f(ux, x∈Z. We prove weak and strong maximum and minimum principles for corresponding initial-boundary value problems. Whereas the maximum principles in the semidiscrete case (continuous time exhibit similar features to those of fully continuous reaction-diffusion model, in the discrete case the weak maximum principle holds for a smaller class of functions and the strong maximum principle is valid in a weaker sense. We describe in detail how the validity of maximum principles depends on the nonlinearity and the time step. We illustrate our results on the Nagumo equation with the bistable nonlinearity.
Experimental study on prediction model for maximum rebound ratio
LEI Wei-dong; TENG Jun; A.HEFNY; ZHAO Jian; GUAN Jiong
2007-01-01
The proposed prediction model for estimating the maximum rebound ratio was applied to a field explosion test, Mandai test in Singapore.The estimated possible maximum Deak particle velocities(PPVs)were compared with the field records.Three of the four available field-recorded PPVs lie exactly below the estimated possible maximum values as expected.while the fourth available field-recorded PPV lies close to and a bit higher than the estimated maximum possible PPV The comparison results show that the predicted PPVs from the proposed prediction model for the maximum rebound ratio match the field.recorded PPVs better than those from two empirical formulae.The very good agreement between the estimated and field-recorded values validates the proposed prediction model for estimating PPV in a rock mass with a set of ipints due to application of a two dimensional compressional wave at the boundary of a tunnel or a borehole.
76 FR 52871 - Pseudomonas fluorescens Strain CL145A; Exemption From the Requirement of a Tolerance
2011-08-24
... AGENCY 40 CFR Part 180 Pseudomonas fluorescens Strain CL145A; Exemption From the Requirement of a... establishes an exemption from the requirement of a tolerance for residues of Pseudomonas fluorescens strain... eliminates the need to establish a maximum permissible level for residues of Pseudomonas fluorescens...
Strain distribution of strips with spherical inclusion during cold rolling
YU Hai-liang; BI Hong-yun; LIU Xiang-hua; TU Yan-feng
2008-01-01
The deformation of 304 stainless steel strips with a spherical inclusion during cold rolling was simulated by 3D finite element method, and the strain distribution was calculated for a variety of the material attribution of inclusion (hard inclusions and soft inclusions) and the inclusion size (10, 20, 30, 40, and 50 μm). During rolling, the strain in front of inclusion is larger than that in rear of inclusion for both the hard and soft inclusions. For hard inclusions, the strain in front and rear of inclusions is larger than that of inclusions, and the maximum and minimum strains increase with the increase of inclusion diameter (from 10 μm to 50 μm). For soft inclusions, the strain in front and rear of inclusions is smaller than that of inclusions, and the maximum and minimum strains decrease with the increase of inclusion sizes when the inclusion diameter is larger than 20 μm but increase when the inclusion diameter is smaller than 20 μm. Finally, the relationship between the inclusion deformation and the crack generation was discussed.
Well Conductor Strain Monitoring
2014-05-06
comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE JUL 2014 2. REPORT TYPE 3. DATES...849,429; filed on June 26, 2013 by the inventor, Dr. Anthony Ruffa and entitled “ SUBSEA WELL CONDUCTOR STRAIN MONITORING”. STATEMENT OF
Influence of inherent strain on the curie temperature of rare earth ion-doped bismuth vanadate
Sooryanarayana, K; Row, TNG; R. Somashekar; Varma, KBR
1998-01-01
X-ray line broadening is found to be an effective parameter to estimate the strain associated with rare earth ion (Gd3+)-doped polycrystalline bismuth vanadate(Bi2VO5.5). The strain increases with increasing Gd3+ concentration. It is anisotropic and found to be maximum in (111) plane. The Curie temperature which is known to decrease with increase in the rare earth ion concentration in these compounds is correlated with increase in strain.
Spectra of fiber Bragg grating and long period fiber grating undergoing linear and quadratic strain
YUAN Yin-quan; LIANG Lei; ZHANG Dong-eheng
2009-01-01
The effects of linear and quadratic strain on the reflective spectrum of FBG and the transmission spectrum of LPFG have been numerically investigated based on the coupled -mode equations. The results show that for the FBG or LPFG undergo-ing only linear strain, the reflection or transmission spectrum is symmetrical about its central wavelength, the dependence relationships of the central wavelength shift, full-width-at-half-maximum, peak intensity upon the strain gradient have been obtained.
Shrinkage strain – Rates study of dental composites based on (BisGMA/TEGDMA monomers
A. Amirouche-Korichi
2017-02-01
The results revealed that the fraction of opaque filler had no significant effect on the shrinkage strain-rate and on the time at maximum shrinkage strain-rate but these two parameters are closely related to the monomer ratios and viscosity of the organic matrix. The results have confirmed the proportionality of the shrinkage strain and DC and showed that the filler contents and monomer ratios would not affect this proportionality.
On the relationship between disbond growth and the release of strain energy
Pascoe, J.A.; Alderliesten, R.C.; Benedictus, R.
2014-01-01
Current prediction methods for growth of disbonds under fatigue loading are generally based on a correlation with either the maximum strain energy release rate (SERR) or the SERR range. This paper highlights some issues with this approach. In particular, it is argued that the maximum SERR or the SE
Perepelyuk, Maryna; Chin, LiKang; Cao, Xuan; van Oosten, Anne; Shenoy, Vivek B; Janmey, Paul A; Wells, Rebecca G
2016-01-01
Tissues including liver stiffen and acquire more extracellular matrix with fibrosis. The relationship between matrix content and stiffness, however, is non-linear, and stiffness is only one component of tissue mechanics. The mechanical response of tissues such as liver to physiological stresses is not well described, and models of tissue mechanics are limited. To better understand the mechanics of the normal and fibrotic rat liver, we carried out a series of studies using parallel plate rheometry, measuring the response to compressive, extensional, and shear strains. We found that the shear storage and loss moduli G' and G" and the apparent Young's moduli measured by uniaxial strain orthogonal to the shear direction increased markedly with both progressive fibrosis and increasing compression, that livers shear strain softened, and that significant increases in shear modulus with compressional stress occurred within a range consistent with increased sinusoidal pressures in liver disease. Proteoglycan content and integrin-matrix interactions were significant determinants of liver mechanics, particularly in compression. We propose a new non-linear constitutive model of the liver. A key feature of this model is that, while it assumes overall liver incompressibility, it takes into account water flow and solid phase compressibility. In sum, we report a detailed study of non-linear liver mechanics under physiological strains in the normal state, early fibrosis, and late fibrosis. We propose a constitutive model that captures compression stiffening, tension softening, and shear softening, and can be understood in terms of the cellular and matrix components of the liver.
2010-07-01
... as specified in 40 CFR 1065.610. This is the maximum in-use engine speed used for calculating the NOX... procedures of 40 CFR part 1065, based on the manufacturer's design and production specifications for the..., power density, and maximum in-use engine speed. 1042.140 Section 1042.140 Protection of...
Sreenivasulu Tadakaluru
2014-01-01
Full Text Available Conventional metallic strain sensors are flexible, but they can sustain maximum strains of only ~5%, so there is a need for sensors that can bear high strains for multifunctional applications. In this study, we report stretchable and flexible high-strain sensors that consist of entangled and randomly distributed multiwall carbon nanotubes or graphite flakes on a natural rubber substrate. Carbon nanotubes/graphite flakes were sandwiched in natural rubber to produce these high-strain sensors. Using field emission scanning electron microscopy, the morphology of the films for both the carbon nanotube and graphite sensors were assessed under different strain conditions (0% and 400% strain. As the strain was increased, the films fractured, resulting in an increase in the electrical resistance of the sensor; this change was reversible. Strains of up to 246% (graphite sensor and 620% (carbon nanotube sensor were measured; these values are respectively ~50 and ~120 times greater than those of conventional metallic strain sensors.
Tadakaluru, Sreenivasulu; Thongsuwan, Wiradej; Singjai, Pisith
2014-01-06
Conventional metallic strain sensors are flexible, but they can sustain maximum strains of only ~5%, so there is a need for sensors that can bear high strains for multifunctional applications. In this study, we report stretchable and flexible high-strain sensors that consist of entangled and randomly distributed multiwall carbon nanotubes or graphite flakes on a natural rubber substrate. Carbon nanotubes/graphite flakes were sandwiched in natural rubber to produce these high-strain sensors. Using field emission scanning electron microscopy, the morphology of the films for both the carbon nanotube and graphite sensors were assessed under different strain conditions (0% and 400% strain). As the strain was increased, the films fractured, resulting in an increase in the electrical resistance of the sensor; this change was reversible. Strains of up to 246% (graphite sensor) and 620% (carbon nanotube sensor) were measured; these values are respectively ~50 and ~120 times greater than those of conventional metallic strain sensors.
Cardiac biplane strain imaging: initial in vivo experience
Lopata, R G P; Nillesen, M M; Thijssen, J M; De Korte, C L [Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Verrijp, C N; Lammens, M M Y; Van der Laak, J A W M [Department of Pathology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Singh, S K; Van Wetten, H B [Department of Cardiothoracic Surgery, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Kapusta, L [Pediatric Cardiology, Department of Pediatrics, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands)], E-mail: R.Lopata@cukz.umcn.nl
2010-02-21
In this study, first we propose a biplane strain imaging method using a commercial ultrasound system, yielding estimation of the strain in three orthogonal directions. Secondly, an animal model of a child's heart was introduced that is suitable to simulate congenital heart disease and was used to test the method in vivo. The proposed approach can serve as a framework to monitor the development of cardiac hypertrophy and fibrosis. A 2D strain estimation technique using radio frequency (RF) ultrasound data was applied. Biplane image acquisition was performed at a relatively low frame rate (<100 Hz) using a commercial platform with an RF interface. For testing the method in vivo, biplane image sequences of the heart were recorded during the cardiac cycle in four dogs with an aortic stenosis. Initial results reveal the feasibility of measuring large radial, circumferential and longitudinal cumulative strain (up to 70%) at a frame rate of 100 Hz. Mean radial strain curves of a manually segmented region-of-interest in the infero-lateral wall show excellent correlation between the measured strain curves acquired in two perpendicular planes. Furthermore, the results show the feasibility and reproducibility of assessing radial, circumferential and longitudinal strains simultaneously. In this preliminary study, three beagles developed an elevated pressure gradient over the aortic valve ({delta}p: 100-200 mmHg) and myocardial hypertrophy. One dog did not develop any sign of hypertrophy ({delta}p = 20 mmHg). Initial strain (rate) results showed that the maximum strain (rate) decreased with increasing valvular stenosis (-50%), which is in accordance with previous studies. Histological findings corroborated these results and showed an increase in fibrotic tissue for the hearts with larger pressure gradients (100, 200 mmHg), as well as lower strain and strain rate values.
Cardiac biplane strain imaging: initial in vivo experience
Lopata, R. G. P.; Nillesen, M. M.; Verrijp, C. N.; Singh, S. K.; Lammens, M. M. Y.; van der Laak, J. A. W. M.; van Wetten, H. B.; Thijssen, J. M.; Kapusta, L.; de Korte, C. L.
2010-02-01
In this study, first we propose a biplane strain imaging method using a commercial ultrasound system, yielding estimation of the strain in three orthogonal directions. Secondly, an animal model of a child's heart was introduced that is suitable to simulate congenital heart disease and was used to test the method in vivo. The proposed approach can serve as a framework to monitor the development of cardiac hypertrophy and fibrosis. A 2D strain estimation technique using radio frequency (RF) ultrasound data was applied. Biplane image acquisition was performed at a relatively low frame rate (cardiac cycle in four dogs with an aortic stenosis. Initial results reveal the feasibility of measuring large radial, circumferential and longitudinal cumulative strain (up to 70%) at a frame rate of 100 Hz. Mean radial strain curves of a manually segmented region-of-interest in the infero-lateral wall show excellent correlation between the measured strain curves acquired in two perpendicular planes. Furthermore, the results show the feasibility and reproducibility of assessing radial, circumferential and longitudinal strains simultaneously. In this preliminary study, three beagles developed an elevated pressure gradient over the aortic valve (Δp: 100-200 mmHg) and myocardial hypertrophy. One dog did not develop any sign of hypertrophy (Δp = 20 mmHg). Initial strain (rate) results showed that the maximum strain (rate) decreased with increasing valvular stenosis (-50%), which is in accordance with previous studies. Histological findings corroborated these results and showed an increase in fibrotic tissue for the hearts with larger pressure gradients (100, 200 mmHg), as well as lower strain and strain rate values.
Stone, Wesley W.; Gilliom, Robert J.; Crawford, Charles G.
2008-01-01
Regression models were developed for predicting annual maximum and selected annual maximum moving-average concentrations of atrazine in streams using the Watershed Regressions for Pesticides (WARP) methodology developed by the National Water-Quality Assessment Program (NAWQA) of the U.S. Geological Survey (USGS). The current effort builds on the original WARP models, which were based on the annual mean and selected percentiles of the annual frequency distribution of atrazine concentrations. Estimates of annual maximum and annual maximum moving-average concentrations for selected durations are needed to characterize the levels of atrazine and other pesticides for comparison to specific water-quality benchmarks for evaluation of potential concerns regarding human health or aquatic life. Separate regression models were derived for the annual maximum and annual maximum 21-day, 60-day, and 90-day moving-average concentrations. Development of the regression models used the same explanatory variables, transformations, model development data, model validation data, and regression methods as those used in the original development of WARP. The models accounted for 72 to 75 percent of the variability in the concentration statistics among the 112 sampling sites used for model development. Predicted concentration statistics from the four models were within a factor of 10 of the observed concentration statistics for most of the model development and validation sites. Overall, performance of the models for the development and validation sites supports the application of the WARP models for predicting annual maximum and selected annual maximum moving-average atrazine concentration in streams and provides a framework to interpret the predictions in terms of uncertainty. For streams with inadequate direct measurements of atrazine concentrations, the WARP model predictions for the annual maximum and the annual maximum moving-average atrazine concentrations can be used to characterize
Maximum Likelihood Estimation of the Identification Parameters and Its Correction
无
2002-01-01
By taking the subsequence out of the input-output sequence of a system polluted by white noise, anindependent observation sequence and its probability density are obtained and then a maximum likelihood estimation of theidentification parameters is given. In order to decrease the asymptotic error, a corrector of maximum likelihood (CML)estimation with its recursive algorithm is given. It has been proved that the corrector has smaller asymptotic error thanthe least square methods. A simulation example shows that the corrector of maximum likelihood estimation is of higherapproximating precision to the true parameters than the least square methods.
Maximum frequency of the decametric radiation from Jupiter
Barrow, C. H.; Alexander, J. K.
1980-01-01
The upper frequency limits of Jupiter's decametric radio emission are found to be essentially the same when observed from the earth or, with considerably higher sensitivity, from the Voyager spacecraft close to Jupiter. This suggests that the maximum frequency is a real cut-off corresponding to a maximum gyrofrequency of about 38-40 MHz at Jupiter. It no longer appears to be necessary to specify different cut-off frequencies for the Io and non-Io emission as the maximum frequencies are roughly the same in each case.
Minakuchi, Shu; Sanada, Teruhisa; Takeda, Nobuo; Mitani, Shinji; Mizutani, Tadahito; Sasaki, Yoshinobu; Shinozaki, Keisuke
2014-05-01
Thermal strain significantly affects stability of fiber optic gyroscope (FOG) performance. This study investigates thermal strain development in a lightweight carbon fiber reinforced plastic (CFRP) FOG under thermal vacuum condition simulating space environment. First, we measure thermal strain distribution along an optical fiber in a CFRP FOG using a Brillouin-based high-spatial resolution system. The key strain profile is clarified and the strain development is simulated using finite element analysis. Finally, several constituent materials for FOG are quantitatively compared from the aspect of the maximum thermal strain and the density, confirming the clear advantage of CFRP.
Yuan, Scott Wu; Stefani, Alessio; Bang, Ole
2012-01-01
We demonstrate stable wavelength tunable inscription of polymer optical fiber Bragg gratings (FBGs). By straining the fiber during FBG inscription, we linearly tune the center wavelength over 7 nm with less than 1% strain. Above 1% strain, the tuning curve saturates and we show a maximum tuning...... of 12 nm with 2.25% strain. We use this inscription method to fabricate a dual-FBG strain sensor in a poly (methyl methacrylate) single-mode microstructured polymer optical fiber and demonstrate temperature compensated strain sensing around 850 nm....
Strain localization and damage development in 2060 alloy during bending
Xiao Jin; Bao-qin Fu; Cheng-lu Zhang; Wei Liu
2015-01-01
The microstructure evolution and damage development of the third-generation Al–Li alloy 2060 (T8) were studied using in situ bending tests. Specimens were loaded with a series of punches of different radii, and the microstructure evolution was studied by scanning electron microscopy, electron backscatter diffraction, and digital image correlation (DIC) methods. The evolution of the microscopic fracture strain distribution and microstructure in 2060 alloy during bending was characterized, where the dispersion distribution of precipitates was recorded by backscattered electron imaging and later inputted into a DIC system for strain calculations. The experimental results showed that strain localization in the free surface of bent specimens induced damage to the microstructure. The region of crack initiation lies on the free surface with maximum strain, and the shear crack propagates along the macro-shear band in the early stages of bending. Crack propagation in the later stages was interpreted on the basis of the conventional mechanism of ductile fracture.
Ratnasamy Muniandy
2006-01-01
Full Text Available Stone Matrix Asphalt (SMA is a gap-graded mix that is gaining popularity worldwide. Generally, gap graded mixes are thought to be weak in fatigue resistance. In this study, cellulose fibers were pre-blended in PG64-22 binder with fiber proportions of 0.2%, 0.4%, 0.6%, 0.8% and 1.0% by weight of aggregates. The fiber-modified binder showed improved rheological properties and showed that the PG64-22 binder can be modified and raised to PG70-22 grade. The cellulose oil palm fiber (COPF was found to improve the diameteral fatigue performance of SMA design mix. The fatigue life increased to a maximum at a fiber content of about 0.6%, whilst the tensile stress and stiffness also showed a similar trend in performance. The initial strains of the mix were lowest at a fiber content of 0.6%.
Stress, strain rate and anisotropy in Kyushu, Japan
Savage, M. K.; Aoki, Y.; Unglert, K.; Ohkura, T.; Umakoshi, K.; Shimizu, H.; Iguchi, M.; Tameguri, T.; Ohminato, T.; Mori, J.
2016-04-01
Seismic anisotropy, the directional dependence of wave speeds, may be caused by stress-oriented cracks or by strain-oriented minerals, yet few studies have quantitatively compared anisotropy to stress and strain over large regions. Here we compare crustal stress and strain rates on the Island of Kyushu, Japan, as measured from inversions of focal mechanisms, GPS and shear wave splitting. Over 85,000 shear wave splitting measurements from local and regional earthquakes are obtained from the NIED network between 2004 and 2012, and on Aso, Sakurajima, Kirishima and Unzen volcano networks. Strain rate measurements are made from the Japanese Geonet stations. JMA-determined S arrival times processed with the MFAST shear wave splitting code measure fast polarisations (Φ), related to the orientation of the anisotropic medium and time delays (dt), related to the path length and the percent anisotropy. We apply the TESSA 2-D delay time tomography and spatial averaging code to the highest quality events, which have nearly vertical incidence angles, separating the 3455 shallow (depth = 40 km) earthquakes. Using square grids with 30 km sides for all the inversions, the best correlations are observed between splitting from shallow earthquakes and stress. Axes of maximum horizontal stress (SHmax) and Φ correlate with a coefficient c of 0.56, significant at the 99% confidence level. Their mean difference is 31.9°. Axes of maximum compressional strain rate and SHmax are also well aligned, with an average difference of 28°, but they do not correlate with each other, meaning that where they differ, the difference is not systematic. Anisotropy strength is negatively correlated with the stress ratio parameter determined from focal mechanism inversion (c = - 0.64; significant at the 99% confidence level). The anisotropy and stress results are consistent with stress-aligned microcracks in the crust in a dominantly strike-slip regime. Eigenvalues of maximum horizontal strain rate
Bini, Donato; Geralico, Andrea
2014-01-01
The definition of relative accelerations and strains among a set of comoving particles is studied in connection with the geometric properties of the frame adapted to a "fiducial observer." We find that a relativistically complete and correct definition of strains must take into account the transport law of the chosen spatial triad along the observer's congruence. We use special congruences of (accelerated) test particles in some familiar spacetimes to elucidate such a point. The celebrated idea of Szekeres' compass of inertia, arising when studying geodesic deviation among a set of free-falling particles, is here generalized to the case of accelerated particles. In doing so we have naturally contributed to the theory of relativistic gravity gradiometer. Moreover, our analysis was made in an observer-dependent form, a fact that would be very useful when thinking about general relativistic tests on space stations orbiting compact objects like black holes and also in other interesting gravitational situations.
The Application of Maximum Principle in Supply Chain Cost Optimization
Zhou Ling; Wang Jun
2013-01-01
In this paper, using the maximum principle for analyzing dynamic cost, we propose a new two-stage supply chain model of the manufacturing-assembly mode for high-tech perishable products supply chain...
Maximum Principle for Nonlinear Cooperative Elliptic Systems on IR N
LEADI Liamidi; MARCOS Aboubacar
2011-01-01
We investigate in this work necessary and sufficient conditions for having a Maximum Principle for a cooperative elliptic system on the whole (IR)N.Moreover,we prove the existence of solutions by an approximation method for the considered system.
Maximum Likelihood Factor Structure of the Family Environment Scale.
Fowler, Patrick C.
1981-01-01
Presents the maximum likelihood factor structure of the Family Environment Scale. The first bipolar dimension, "cohesion v conflict," measures relationship-centered concerns, while the second unipolar dimension is an index of "organizational and control" activities. (Author)
Multiresolution maximum intensity volume rendering by morphological adjunction pyramids
Roerdink, Jos B.T.M.
We describe a multiresolution extension to maximum intensity projection (MIP) volume rendering, allowing progressive refinement and perfect reconstruction. The method makes use of morphological adjunction pyramids. The pyramidal analysis and synthesis operators are composed of morphological 3-D