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Sample records for brittle-ductile transitions

  1. Study on the cutting mechanism and the brittle ductile transition model of isotropic pyrolyric graphite

    Science.gov (United States)

    Wang, Minghai; Wang, Hujun; Liu, Zhonghai

    2011-05-01

    Isotropic pyrolyric graphite (IPG) is a new kind of brittle material, it can be used for sealing the aero-engine turbine shaft and the ethylene high-temperature equipment. It not only has the general advantages of ordinal carbonaceous materials such as high temperature resistance, lubrication and abrasion resistance, but also has the advantages of impermeability and machinability that carbon/carbon composite doesn't have. Therefore, it has broad prospects for development. Mechanism of brittle-ductile transition of IPG is the foundation of precision cutting while the plastic deformation of IPG is the essential and the most important mechanical behavior of precision cutting. Using the theory of strain gradient, the mechanism of this material removal during the precision cutting is analyzed. The critical cutting thickness of IPG is calculated for the first time. Furthermore, the cutting process parameters such as cutting depth, feed rate which corresponding to the scale of brittle-ductile transition deformation of IPG are calculated. In the end, based on the theory of micromechanics, the deformation behaviors of IPG such as brittle fracture, plastic deformation and mutual transformation process are all simulated under the Sih.G.C fracture criterion. The condition of the simulation is that the material under the pressure-shear loading conditions .The result shows that the best angle during the IPG precision cutting is -30°. The theoretical analysis and the simulation result are validated by precision cutting experiments.

  2. Slip transfer across fault discontinuities within granitic rock at the brittle-ductile transition

    Science.gov (United States)

    Nevitt, J. M.; Pollard, D. D.; Warren, J. M.

    2011-12-01

    Fault mechanics are strongly influenced by discontinuities in fault geometry and constitutive differences between the brittle and ductile regions of the lithosphere. This project uses field observations, laboratory analysis and numerical modeling to investigate deformational processes within a contractional step at the brittle-ductile transition, and in particular, how slip is transferred between faults via ductile deformation across the step. The Bear Creek field area (central Sierra Nevada, CA) is comprised of late Cretaceous biotite-hornblende granodiorite and experienced a period of faulting at the brittle-ductile transition. Abundant echelon faults in Bear Creek, some of which were seismically active, provide many textbook examples of contractional steps, which are characterized by well-developed ductile fabrics. The occurrence of hydrothermal alteration halos and hydrothermal minerals in fracture fill documents the presence of water, which we suggest played a weakening role in the constitutive behavior of the granodiorite. Furthermore, the mechanism that accomplishes slip transfer in contractional steps appears to be related to water-enhanced ductile deformation. We focus our investigation on Outcrop SG10, which features a 10cm thick aplite dike that is offset 0.45m through a contractional step between two sub-parallel left-lateral faults. Within the step, the aplite undergoes dramatic thinning (stretch ~1/10) and the granodiorite is characterized by a well-developed mylonitic foliation, in which quartz and biotite plastically flow around larger grains of feldspars, hornblende and opaque minerals. Electron backscatter diffraction (EBSD) analysis gives a more quantitative depiction of the active micromechanics and reveals how slip is accommodated at the crystal scale throughout the step. We use Abaqus, a commercial finite element software, to test several constitutive laws that may account for the deformation observed both macro- and microscopically throughout

  3. THE EFFECT OF MATRIX TOUGHNESS ON THE BRITTLE-DUCTILE TRANSITION OF HDPE/CaCO3 BLENDS

    Institute of Scientific and Technical Information of China (English)

    FU Qiang; ZHANG Yulin; WANG Guiheng

    1994-01-01

    The effects of HDPE matrix toughness on the brittle-ductile transition of HDPE/CaCO3 blends are investigated. Not all HDPE can be toughened by CaCO3 particles. The ability of the matrix to yield plays a fundamental role in determing whether HDPE can be toughened or not.There exists a critical matrix toughness (Isc≈45J/m) below which HDPE can not be toughened observably by CaCO3 particle at given average size, and above which the critical matrix ligament thickness (τc) is proportional to matrix impact strength.

  4. 3D Imaging of Brittle/Ductile transition of the crust beneath the resurgent calderas

    Science.gov (United States)

    Tizzani, P.; Castaldo, R.; Pepe, S.; Solaro, G.

    2012-04-01

    Rheology is a crucial factor to understand the mechanical behaviour and evolution of the crust in young and tectonically active belts. The aim of this paper is to investigate the rheological properties of the crust beneath resurgent calderas as Long Valley caldera (California USA) and Campi Flegrei (Southern Italy). Through the rheological proprieties of the calderas area, we highlight the driving process that determine the cut off of the local seismicity [K. Ito, 1993]. In this context, we consider the thermal proprieties and mechanical heterogeneity of the crust in order to develop a 3D conductive time dependent thermal model of the upper crust beneath the two calderas. More specifically we integrate geophysical information (gravimetric, seismic and boreholes data) available for the considered area in FEM environment [Manconi A. et al., 2010]. We performed a numerical solution of Fourier equation to carry out an advance optimization of the real measured data. We produce a set of forward models and propose, in order to analyse and solve the statistical problem, the Monte Carlo optimization procedures as Genetic Algorithm [Manconi A. et al., 2009]. In particular we search for the heat production, the volume source distribution and the surface emissivity parameters that providing the best-fit of the geothermal profiles data measured at boreholes, by solving the non stationary heat flow equation (Campanian Ignimbrite eruption about 40 kyr for Campi Flegrei caldera and Bishop tuff eruption about 700 kyr for Long Valley caldera). The performed thermal fields allow us to obtain the rheological stratification of the crust beneath two resurgent calderas; the models suggest that the uprising of a ductile layer which connects the upper mantle to the volcanic feeding system could determine the stress conditions that controlled the distribution of seismicity. In fact, the computed 3D imaging of Brittle/Ductile transition well agrees with the seismic hypocentral distribution

  5. Brittle ductile transition in experimentally deformed basalt under oceanic crust conditions

    Science.gov (United States)

    Violay, M.; Gibert, B.; Mainprice, D.; Evans, B.; Pezard, P. A.; Flovenz, O.

    2009-04-01

    The mid-ocean ridge system is the largest continuous volcanic feature on Earth, with significant interactions between tectonic activity, volcanism and sea-water circulation. Iceland is the biggest landmass straddling a mid-ocean ridge. The associated tectonic and volcanic settings resulting from the active rifting provide in this geodynamic context a major heat source for the geothermal exploitation. High-pressure, high-temperature, conventional triaxial compression experiments have been conducted in a Paterson Press to explore the brittle-ductile transition of oceanic crustal rocks under in situ conditions at depth (3-10 Km). The study provides some insights into the prospect of producing geothermal fluids from deep wells drilled into a reservoir at temperatures and pressures of supercritical water (T>400°C). We present a series of 20 axial compression deformation experiments performed on jacketed basalt cores of 10 mm diameter and 20 mm long. The experiments were performed at 100 and 300 MPa, with temperatures ranging from 400°C to 900°C, and pore pressures ranging from 0 to 100 MPa, a constant strain rate of 1 × 10- 5 s- 1 and up to strains of 15%. Two different types of basalts were selected for their simple compositions, low alteration degree and very low porosity (3%). The two samples differed in their percentage of glass, being zero in one case and 15% in the other. For the vitreous sample at a confining pressure of 100 and 300 MPa, our experiments show that deformation takes place by three deformation modes; (1) brittle fracture at 400°C with a maximal strength of 900 MPa, corresponding to failure by localized rupture, (2) strain-hardening at small strains and followed by slipping on a localized fracture plane at a constant strength around 250 MPa at higher strains, for temperatures ranging from 500°C to 700°C, (3) distributed ductile flow at differential stresses from 50 to 100 MPa and temperature from 800 to 900°C. For the non glassy sample, the

  6. Micro- and submicrostructural evidence for high-temperature brittle-ductile transition deformation of hornblende: Case study of high-grade mylonites from Diancangshan, western Yunnan

    Institute of Scientific and Technical Information of China (English)

    CAO; ShuYun; LIU; JunLai; HU; Ling

    2007-01-01

    OM (optical microscope)/TEM (transmission electron microscope) micro- and submicrostructural analysis of hornblende rocks sheared at high temperatures from the Diancangshan area, western Yunnan reveals evidence for deformation in the brittle-ductile transition of hornblende at middle crustal level (about 637℃ and 0.653 GPa) and mechanisms of deformation in the transitional regime are further discussed. Sheared hornblende rocks at middle crustal level have typical mylonitic microstructures, shown by coarse porphyroclasts and fine matrix grains. Different mineral phases in the rocks show distinct deformation characteristics. Hornblende and feldspar grains are intensely deformed with obvious grainsize reduction, but quartz grains are recrystallized dominantly by grain growth. Hornblende grains show typical brittle-ductile transition nature. Initial crystallographic orientations of porphyroclasts have strong effects on the behavior of grains during deformation. There are mainly two types of porphyroclasts, type I "hard" porphyroclasts and type II "soft" porphyroclasts, with [001] perpendicular and parallel to external shear stresses respectively. "Hard" porphyroclasts generally occur as competent grains that are rarely deformed or sometimes deformed by fracturing and dislocation tangling. "Soft" porphyroclasts are highly deformed primarily by dislocation tangling (as shown in the cores of the porphyroclasts), but twinning, dislocation glide and climb probably due to hydrolytic weakening also contribute to dynamic recrystallization of the porphyroclasts into fine grains in the matrix. The micro- and submicrostructures of the two types of porphyroclasts and fine-grained matrix provide powerful evidence for the behavior of brittle-ductile transition of hornblende grains. It is concluded that twinning nucleation is one of the most important processes that operate during dynamic recrystallization of hornblende crystals at the brittle-ductile transition. (100) [001] twin

  7. Influence of lithologic variability on the rheology of granitic rock deformed near the brittle-ductile transition (Invited)

    Science.gov (United States)

    Nevitt, J. M.; Pollard, D. D.; Warren, J. M.

    2013-12-01

    Examining fault-related deformation under brittle-ductile conditions and across different lithologies has implications for seismic hazard analysis, since earthquakes are thought to nucleate near the brittle-ductile transition and fault slip distributions are influenced by lithologic variations. This presentation focuses on two outcrops containing lithologic heterogeneities - the Seven Gables (SG) outcrop and the Sheared Schlieren (SS) outcrop - to investigate the relationship between lithology and deformation. This is accomplished through a combination of field observations, micro-structural/-chemical analyses, and mechanics-based finite element models. The SG and SS outcrops are located in the Bear Creek field area (central Sierra Nevada, CA), which consists of a medium- to fine-grained biotite-hornblende granodiorite with a weak regional foliation trending approximately northwest. The field area contains abundant faults, which microstructural observations suggest were active near the brittle-ductile transition. Furthermore, leucocratic dikes, volcanic xenoliths, and schlieren are abundant throughout the granodiorite, making it lithologically heterogeneous at the decimeter- to meter-scale. The SG outcrop allows comparison of granodiorite rheology to that of a leucocratic dike, both of which are ductilely deformed within a contractional fault step. Both lithologies contain plagioclase, K-feldspar, and quartz, with the granodiorite also containing biotite, hornblende, and sphene. The 10 cm wide right step occurs between two left-lateral faults, measuring 1 and 2 m in length, respectively. A 4 cm thick leucocratic dike runs directly through the center of the step at an angle of 70° to the faults, as measured in the plane of the outcrop. Microstructural analysis indicates that the dominant quartz slip system within the center of the step is basal . The SS outcrop contains a schlieren that is ductilely sheared in the near-tip region of a left-lateral fault. The

  8. Simulation of seismic waves at the Earth crust (brittle-ductile transition based on the Burgers model

    Directory of Open Access Journals (Sweden)

    J. M. Carcione

    2014-06-01

    Full Text Available The Earth crust presents two dissimilar rheological behaviours depending on the in-situ stress-temperature conditions. The upper, cooler, part is brittle while deeper zones are ductile. Seismic waves may reveal the presence of the transition but a proper characterization is required. We first obtain a stress–strain relation including the effects of shear seismic attenuation and ductility due to shear deformations and plastic flow. The anelastic behaviour is based on the Burgers mechanical model to describe the effects of seismic attenuation and steady-state creep flow. The shear Lamé constant of the brittle and ductile media depends on the in-situ stress and temperature through the shear viscosity, which is obtained by the Arrhenius equation and the octahedral stress criterion. The P- and S-wave velocities decrease as depth and temperature increase due to the geothermal gradient, an effect which is more pronounced for shear waves. We then obtain the P-S and SH equations of motion recast in the velocity-stress formulation, including memory variables to avoid the computation of time convolutions. The equations correspond to isotropic anelastic and inhomogeneous media and are solved by a direct grid method based on the Runge–Kutta time stepping technique and the Fourier pseudospectral method. The algorithm is tested with success against known analytical solutions for different shear viscosities. A realistic example illustrates the computation of surface and reverse-VSP synthetic seismograms in the presence of an abrupt brittle-ductile transition.

  9. EFFECTS OF INTERPARTICLE DISTANCE,TEMPERATURE AND INTERFACIAL ADHESION ON BRITTLE-DUCTILE TRANSITION FOR NYLON 6/ABS BLENDS

    Institute of Scientific and Technical Information of China (English)

    Shu-hao Qin; Jie Yu; Min He; Wei Yan

    2009-01-01

    The toughness of blends composed of nylon 6 and acrylonitrile-butadiene-styrene(ABS)compatibilized by using styrene-maleic anhydride(SMA)as a compatibilizer was measured over a wide temperature region.Results reveal that the combining effects of particle size and volume fraction of ABS on the toughness of nylon 6/ABS/SMA blends can be described through plotting brittle-ductile transition of the impact strength versus the interparticle distance(ID)on the assumption that ABS domains relieve the triaxial tension via internal cavitation or interfacial debonding.Moreover,the effect of interfacial adhesion on fracture behavior of nylon 6/ABS/SMA blends strongly depends upon the testing temperature.The difference of relation amomg temperature,fracture behavior and interfacial adhesion can be understood in terms of the deformation mechanisms,i.e.in the case of poor interfacial adhesion,the toughness lies on whether debonding existing at the interface relieves triaxial tension or not.It is believed that for good interfacial adhesion,internal cavitation followed by matrix shear yielding is a predominant factor for toughening.Furthermore,the fracture surface of these blends was probed to elucidate how interfacial adhesion affected the impact strength of the blends.

  10. New constraints on the rheology of granitic rock during faulting at the brittle-ductile transition: field observations, microstructural analysis and mechanical modeling

    Science.gov (United States)

    Nevitt, J. M.; Pollard, D. D.; Warren, J. M.

    2012-12-01

    Mechanical models of fault slip and related deformation are built upon the equations of motion, which require constitutive equations to define the relationship between stress and resulting strain or strain rate. Although the brittle-ductile transition plays a significant role in earthquake nucleation and propagation, constitutive equations governing rock behavior in this crustal interval remain largely unknown. Identifying appropriate constitutive equations will improve our understanding of earthquake mechanics, in addition to our knowledge of the strength of the lithosphere. Outcrops in the Bear Creek drainage (central Sierra Nevada, CA) provide excellent opportunities to investigate structures that develop under brittle-ductile conditions. There, late Cretaceous biotite-hornblende granodiorite contains an abundance of discontinuous left-lateral strike-slip faults, some of which were seismically active based on the presence of pseudotachylyte. The occurrence of both brittle (e.g., cataclastic rock, opening mode fractures) and ductile (e.g., foliation, ductile shear zones) features suggests that deformation likely occurred near the brittle-ductile transition. Microstructural observations indicate that the temperature during deformation was ~450°C, consistent with the brittle-ductile transition in continental crust. The Seven Gables outcrop contains a 4 cm wide aplite dike that is displaced 42 cm through a contractional step. Within the step, the aplite undergoes stretching (180% stretch) and rotation (45° CCW about an axis plunging 21°), while the granodiorite develops a locally strong mylonitic foliation. The aplite dike provides a valuable strain marker from which we deduce the kinematic evolution of faulting at this contractional step under brittle-ductile conditions. The geometry and kinematic model of the Seven Gables outcrop constrain the geometry and boundary conditions of a forward finite element model. The faults are modeled as planar features and obey

  11. Challenges in the Japan Beyond-Brittle Project (JBBP) for EGS development beyond the brittle-ductile transition

    Science.gov (United States)

    Asanuma, H.; Muraoka, H.; Tsuchiya, N.; Ito, H.

    2013-12-01

    Development using Engineered Geothermal System (EGS) technologies is considered to be the best solution to the problems of the localized distribution of geothermal resources. However, it is considered that a number of problems, including low water recovery rate, difficulty in design of the reservoir, and induced earthquake, would appear in Japanese EGS. These problems in the development of EGS reservoirs cannot be readily solved in Japan because they are intrinsically related to the physical characteristics and tectonic setting of the brittle rock mass. Therefore, we have initiated the Japan Beyond-Brittle Project (JBBP), which will take a multidisciplinary scientific approach, including geology, geochemistry, geophysics, water-rock interactions, rock mechanics, seismology, drilling technology, well-logging technology, and reservoir engineering. The science and technology required for the creation and control of geothermal reservoirs in superheated rocks in the ductile zone is at the frontier of modern research in most of the related disciplines. Solutions to the associated problems will not easily be found without international collaboration among researchers and engineers. For this reason, in March, 2013 we held a five-day ICDP-supported workshop in Japan to review and discuss various scientific and technological issues related to the JBBP. Throughout the discussions at the workshop on characteristics of the beyond-brittle rock mass and creation and control of EGS reservoirs in the ductile zone, it has concluded that there are two end-member reservoir models that should be considered (Fig. 1). The JBBP reservoir type-1 would be created near the top of the brittle-ductile transition (BDT) and connected to pre-existing hydrothermal systems, which would increase productivity and provide sustainability. The JBBP reservoir type-2 would be hydraulically or thermally created beyond the BDT, where pre-existing fractures are less permeable, and would be hydraulically

  12. Definition of Brittle Ductile Transition of the upper crust beneath the Campi Flegrei-Ischia Volcanic District and its impact on natural seismicity

    Science.gov (United States)

    Tizzani, Pietro; Castaldo, Raffaele; De Novellis, Vincenzo; Santilano, Alessandro; Gola, Gianluca; Pepe, Susi; D'Auria, Luca; Solaro, Giuseppe

    2016-04-01

    The thermo-rheology behaviour of the rocks is a crucial aspect to understand the mechanical behaviour of the crust of tectonically active area. As a consequence, several studies have been performed since last decades in order to clarify the role of thermic state in the evolution of volcanic areas. In this framework, the knowledge of the Brittle-Ductile transition inside the upper crust may provide insights to verify the roles that some hypothesized mechanisms, such as slab pull, crustal delamination might have played in the evolution of a tectonically active region. The goal of our study was the 3D imaging of the crust rheology beneath the active Campi Flegrei-Ischia Volcanic District and its impact on natural seismicity. Despite many works have been done on the internal structure of the active volcanoes, the determination of the 3D rheological stratification of the crust below the caldera has not yet been tackled. To fill this gap of knowledge, we proposed the definition of 3D geometry of the Brittle-Ductile transition calculated via numerical optimization modelling based on geological, geochemical, and geophysical available data. We first performed a 3D numerical modelling of thermal field by using the a priori geological and geophysical information starting to thermal proprieties and mechanical heterogeneities of the crust beneath the caldera. We developed a suitable 3D conductive/convective time-dependent thermal numerical model solving the Fourier equation and further we used the retrieved thermal model to image a 3D rheological stratification of the shallow crust below the volcanic district. Finally we demonstrate the role of the crustal rheology on seismicity cut off and its implication on maximum expected earthquakes magnitude.

  13. The electronic structure and grain boundary segregation by boron addition——A binding energy shifting criterion for the brittle-ductile fracture transition in Ni3Al

    Institute of Scientific and Technical Information of China (English)

    张云; 林栋梁

    1997-01-01

    The electronic structure and grain boundary segregation caused by boron addition to Ni3Al have been studied by X-ray photoelectron spectroscopy and Auger electron spectroscopy, respectively. The obtained results show that the Ni2p3/2 electron binding energy rises gradually in the sequence of pure Ni< Ni76Al24< Ni74Al26 < Ni25Al25, while it reduces monotonously with an increase in boron addition to Ni3Al. Besides, it is found that the gram boundary segregation of boron occurring in Ni3Al is a combined equilibrium and non-equilibrium type in nature. Based on the concept of the bonding environmental inhomogeneity, measured by the shift in Ni2p3/2 electron binding energy from the nickel atoms in the simple substance nickel to those in the intermetallic compound Ni3Al (ΔEB), being responsible for the brittle behavior of the alloy, a binding energy shifting criterion for the brittle-ductile fracture transition in Ni3Al is presented: when ΔEB>0, the brittle failure occurs in Ni3Al; when ΔEB<0, the ductile o

  14. Temporal correlation between coda Q-1 and seismicity—evidence for a structural unit in the brittle-ductile transition zone

    Science.gov (United States)

    Jin, Anshu; Aki, Keiiti

    1993-07-01

    Analysis of local earthquake coda waves recorded on Wood-Anderson (1940-1947) and Benioff (after 1947) short-period vertical seismographs at station Mt. Hamilton, Calif., revealed a large temporal variation in coda Q-1. A strong positive correlation was found between the temporal variation of coda Q-1 and the number of earthquakes with a magnitude of 4.0⩽ M⩽4.5 appearing in a series of 100 consecutive earthquakes with a magnitude M⩾3.0. A correlation coefficient of 0.84 was determined with a confidence level of 0.98. The amplitude and time constant of variation in coda Q-1 for central California are similar to those found earlier for southern California (Jin and Aki, 1989). The strong correlation between coda Q-1 and b-value reported by Jin and Aki (1989) was shown to be equivalent to a positive correlation between coda Q-1 and the fractional number of earthquakes with a magnitude 3.0⩽ M⩽3.5. A review of the literature reporting observed temporal correlation between coda Q-1 and b-value (both positive and negative) revealed that all the reported observations can be interpreted in terms of a positive correlation between the coda Q-1 and the fractional frequency of earthquakes in a magnitude range around a certain magnitude, Mc, characteristic to each region. This positive correlation has been attributed to the aseismic creep in the brittle-ductile transition zone. Aseismic creep in the transition zone may occur over fractures with a characteristic size for each region. The existence of fractures with a characteristic size would necessarily violate the scale independent self-similarity of earthquake phenomena. This is consistent with the growing literature demonstrating a departure from self-similarity in various seismic phenomena.

  15. Simulation of seismic waves at the Earth crust (brittle-ductile transition) based on the Burgers model

    OpenAIRE

    Carcione, J.M.; Poletto, F.; B. Farina; A. Craglietto

    2014-01-01

    The Earth crust presents two dissimilar rheological behaviours depending on the in-situ stress-temperature conditions. The upper, cooler, part is brittle while deeper zones are ductile. Seismic waves may reveal the presence of the transition but a proper characterization is required. We first obtain a stress–strain relation including the effects of shear seismic attenuation and ductility due to shear deformations and plastic flow. The anelastic behaviour i...

  16. 大理岩脆-延-塑转换特性的细观模拟研究%MESOSCOPIC SIMULATION STUDY OF BRITTLE-DUCTILE-PLASTIC TRANSITION CHARACTER OF MARBLE

    Institute of Scientific and Technical Information of China (English)

    余华中; 阮怀宁; 褚卫江

    2013-01-01

      针对锦屏深埋大理岩峰后变形破坏的脆–延–塑转换特性,采用颗粒流程序(PFC)中的簇单元模型(CPM)对其进行细观模拟研究。经过对室内试验结果的反复模拟校准,获得描述锦屏深埋大理岩力学性质的一组细观物理力学性质参数。模型试验结果表明:试样的一系列宏观力学表现,包括弹性模量、泊松比、单轴与启裂抗压强度、应力–应变曲线、峰值与残余强度包络线、拉压强度比以及破坏形态等均与锦屏深埋大理岩的试验结果具有良好的一致性。对不同围压下裂纹发育规律的研究表明:不同应力状态下细观裂纹发育特征的显著差异是导致大理岩的变形破坏出现脆–延–塑转换特性的主要原因;张性裂纹的大量发育决定介质的脆性破坏模式,而剪切裂纹数目的快速增长则促使介质由脆性破坏模式逐渐向延–塑性破坏模式转换。%The deformation and failure characteristics of brittle-ductile-plastic transition,which is shown in the post-peak stage for Jinping deep marble,was simulated by clumped-particle model(CPM) of particle flow code(PFC),and studied from the micro view. After a long process of trial-and-error calibration of laboratory test results,a set of micro parameters for Jinping deep marble were obtained. It is shown that a series of macroscopic mechanical properties of the synthetic rock,including the elastic modulus,Poisson′s ratio,uniaxial compressive and crack initiation strengths,stress-strain curves,the peak and residual strength envelops,the ratio of tensile to uniaxial compressive strength,and the failure patterns of synthetic rock samples,all agree well with the test results of Jinping deep marble. Study of regularities of crack development in synthetic rock samples at different confining pressures indicates that:The significant difference of development features of microcracks at different confining pressures is

  17. Depth-Dependent Earthquake Properties Beneath Long-Beach, CA: Implications for the Rheology at the Brittle-Ductile Transition Zone

    Science.gov (United States)

    Inbal, A.; Clayton, R. W.; Ampuero, J. P.

    2015-12-01

    Except for a few localities, seismicity along faults in southern California is generally confined to depths shallower than 15 km. Among faults hosting deep seismicity, the Newport-Inglewood Fault (NIF), which traverses the Los-Angeles basin, has an exceptionally mild surface expression and low deformation rates. Moreover, the NIF structure is not as well resolved as other, less well instrumented faults because of poor signal-to-noise ratio. Here we use data from three temporary dense seismic arrays, which were deployed for exploration purposes and contain up to several thousands of vertical geophones, to investigate the properties of deep seismicity beneath Long-Beach (LB), Compton and Santa-Fe Springs (SFS). The latter is located 15 km northeast of the NIF, presumably above a major detachment fault underthrusting the basin.Event detection is carried out using a new approach for microseismic multi-channel picking, in which downward-continued data are back-projected onto the volume beneath the arrays, and locations are derived from statistical analysis of back-projection images. Our technique reveals numerous, previously undetected events along the NIF, and confirms the presence of an active shallow structure gently dipping to the north beneath SFS. Seismicity characteristics vary along the NIF strike and dip. While LB seismicity is uncorrelated with the mapped trace of the NIF, Compton seismicity illuminates a sub-vertical fault that extends down to about 20 km. This result, along with the reported high flux of mantle Helium along the NIF (Boles et al., 2015), suggests that the NIF is deeply rooted and acts as a major conduit for mantle fluids. We find that the LB size distribution obeys the typical power-law at shallow depths, but falls off exponentially for events occurring below 20 km. Because deep seismicity occurs uniformly beneath LB, this transition is attributed to a reduction in seismic asperity density with increasing depth, consistent with a transition

  18. Prediction of non-brittle fracture in the welded joint of C-Mn steel in the brittle-ductile transition domain; Prediction de la non-rupture fragile dans un joint soude en acier C-Mn dans le domaine de la transition fragile/ductile

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Thai Ha

    2009-11-15

    This work concerns the nuclear safety, specifically the secondary circuit integrity of pressurized water reactors (PWR). The problem is that of the fracture of a thin tubular structure in ferritic steel with many welded joints. The ferritic steel and weld present a brittle/ductile tenacity transition. Moreover, the welds present geometry propitious to the appearance of fatigue cracks, due to vibrations and expansions. These cracks may cause the complete fracture of the structure. The objectives of this work are to establish a criterion of non-fracture by cleavage of thin welded structures in ferritic steel, applicable to actual structures. Therefore, the present study focuses on the fracture behaviour of welded thin structures in brittle/ductile transition. It aims at developing the threshold stress model initially proposed by Chapuliot, to predict the non-brittle-fracture of this welded structure. The model is identified for the welded joint in C-Mn steel for nuclear construction, specifically in the upper part of the transition. A threshold stress, below which the cleavage cannot take place, is identified using tensile tests at low temperature on axis-symmetrical notched specimens taken in welded joint. This threshold stress is used to define the threshold volume where the maximum principal stress exceeds the threshold stress during the test. The analysis by SEM of specimen fracture surfaces shows that the gross solidification molten zone in the weld is the most likely to cleave. The relation between the brittle fracture probability and the threshold volume in the gross solidification molten zone is established via a sensitivity function, using multi-materials simulations. The model thus identified is tested for the prediction of non-brittle-fracture of SENT specimens taken in the welded joint and tested in tension. The results obtained are encouraging with regards to the transferability of the model to the actual structure. (author)

  19. Quantification of the brittle-ductile failure behavior of reactor steels by means of the small punch tests and micromechanical damage models; Quantifizierung des sproed-duktilen Versagensverhaltens von Reaktorstaehlen mit Hilfe des Small-Punch-Tests und mikromechanischer Schaedigungsmodelle

    Energy Technology Data Exchange (ETDEWEB)

    Linse, Thomas

    2013-02-25

    This work comprises the development and implementation of a non-local ductile damage model, the application of methods for the identification of material parameters from experimental data as well as the calculation of fracture mechanics parameters in the brittle-ductile transition zone through numerical simulations of fracture mechanical tests using the identified parameters. The developed non-local ductile damage model is based on the Gurson-Tvergaard- Needleman model (GTN). The pathological mesh sensitivity of the GTN model is eliminated by introducing an additional length parameter by means of an implicit gradient formulation. To solve the coupled field problem, the non-local damage model is implemented in a finite element program in the form of a userdefined element. Force-displacement-curves of the small punch test (SPT), a miniaturised test, are evaluated for the determination of material parameters. Given the modest material requirements for the preparation of the required samples remnants of Charpy-specimens are reused. Two ferritic reactor steels, both irradiated and unirradiated, are examined. The experiments cover the full brittle-ductile transition region of the steels. Following the concept of the Local Approach, fracture toughness values are determined by numerical calculation of the stress and deformation state in fracture mechanics specimen only. Here, the yield curves and damage parameters previously determined from the SPT are used. The calculated fracture toughness values are compared with experimental results.

  20. Quantification of brittle-ductile failure behavior of ferritic reactor pressure vessel steels using the Small-Punch-Test and micromechanical damage models

    Energy Technology Data Exchange (ETDEWEB)

    Linse, T., E-mail: thomas.linse@tu-dresden.de [Technische Universität Dresden, Institute for Solid Mechanics, 01062 Dresden (Germany); Kuna, M. [Technische Universität Bergakademie Freiberg, Institute of Mechanics and Fluid Dynamics, Lampadiusstrasse 4, 09596 Freiberg (Germany); Viehrig, H.-W. [Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01328 Dresden (Germany)

    2014-09-22

    Two German ferritic pressure vessel steels are examined in the brittle to ductile transition regime as a function of temperature and irradiation. The experiments are done by a miniaturized Small-Punch-Test in hot cells within the temperature range of −185 °C up to 70 °C. From the load–displacement curve of the SPT, the yield curves and parameters of both a non-local GURSON-TVERGAARD-NEEDLEMAN ductile damage model and a modified BEREMIN model are identified. The influence of temperature and irradiation on the model parameters is analyzed. All parameters are verified by comparison with results from standard test methods. The parameters, identified from SPT, are used to simulate the failure behavior in standard fracture mechanics specimens. In the upper shelf, the non-local GTN-model is applied to simulate crack resistance curves, from where the fracture toughness data could be successfully predicted. In the lower shelf, the WEIBULL-stress of the specimens was computed to find out the statistics of fracture toughness values. Finally, the modified BEREMIN model and the non-local ductile damage model were combined to evaluate the failure of fracture specimens in the brittle-ductile transition region. This way, an acceptable agreement with Master-curve data for non-irradiated steels could be achieved in the whole temperature range.

  1. Brittle-ductile behavior of a nanocrack in nanocrystalline Ni: A quasicontinuum study

    Institute of Scientific and Technical Information of China (English)

    Shao Yu-Fei; Yang Xin; Zhao Xing; Wang Shao-Qing

    2012-01-01

    The effects of stacking fault energy,unstable stacking fault energy,and unstable twinning fault energy on the fracture behavior of nanocrystalline Ni are studied via quasicontinuum simulations.Two semi-empirical potentials for Ni are used to vary the values of these generalized planar fault energies.When the above three energies are reduced,a brittle-to-ductile transition of the fracture behavior is observed.In the model with higher generalized planar fault energies,a nanocrack proceeds along a grain boundary,while in the model with lower energies,the tip of the nanocrack becomes blunt.A greater twinning tendency is also observed in the more ductile model.These results indicate that the fracture toughness of nanocrystalline face-centered-cubic metals and alloys might be efficiently improved by controlling the generalized planar fault energies.

  2. Strain localization in brittle-ductile shear zones: fluid abundant vs fluid limited conditions (an example from Wyangala area, Australia

    Directory of Open Access Journals (Sweden)

    L. Spruzeniece

    2015-04-01

    Full Text Available This study focuses on physiochemical processes occurring in a brittle-ductile shear zone at both fluid-present and fluid-limited conditions. In the studied shear zone (Wyangala, SE Australia, a coarse-grained two feldspar-quartz-biotite granite is transformed into a medium grained orthogneiss at the shear zone margins and a fine-grained quartz-muscovite phyllonite in the central parts. The orthogneiss displays cataclasis of feldspar and crystal-plastic deformation of quartz. Quartz accommodates most of the deformation and is extensively recrystallized showing distinct crystallographic preferred orientation (CPO. Feldspar-to-muscovite, biotite-to-muscovite and albitization reactions occur locally at porphyroclasts' fracture surfaces and margins. However, the bulk rock composition shows very little change in respect to the wall rock composition. In contrast, in the shear zone centre quartz occurs as large, weakly deformed porphyroclasts, in sizes similar to that in the wall rock, suggesting that it has undergone little deformation. Feldspars and biotite are almost completely reacted to muscovite, which is arranged in a fine-grained interconnected matrix. Muscovite-rich layers contain significant amounts of fine-grained intermixed quartz with random CPO. These domains are interpreted to have accommodated most of the strain. Bulk rock chemistry data shows a significant increase in SiO2 and depletion in NaO content compared to the wall rock composition. We suggest that the high and low strain fabrics represent markedly different scenarios and cannot be interpreted as a simple sequential development with respect to strain. We suggest that the fabrics and mineralogical changes in the shear zone centre have formed due to fluid influx probably along an initially brittle fracture. Here, hydration reactions dramatically changed the rheological properties of the rock. In the newly produced muscovite-quartz layers creep cavitation associated with grain

  3. Seismicity and Attenuation Correlation Analysis in the Bucaramanga Nest (Colombia). A Test for the Brittle-Ductile Interaction Hypothesis

    Science.gov (United States)

    Tarela, E.; Pujades, L. G.; Ugalde, A.

    2008-12-01

    Technical advances are nowadays starting to provide data sets covering large enough time windows and allowing studying the time evolution of several seismic parameters with some perspective. We study here, at a local scale, the following items: 1) the time evolution of two of these parameters, the seismicity and the coda-wave-attenuation, 2) their relationship in order to test the brittle-ductile interaction hypothesis of the lithosphere-asthenosphere complex system, and 3) its possible use as a mid-term predictor. Seismicity represents the brittle zone stress state, while the one of the ductile zone is characterized by the attenuation of coda waves, which here is measured through coda-Q quality factor. According to the model, the time series will present a similar variation rate during the calm period of the cycle. About two years before a major earthquake takes place in the region, the stress state of both the brittle and the ductile parts of the lithosphere-asthenosphere system would change and the correlation between the two parameters would break down because of this uncoupling. So, a correlation analysis of the two time series would lead to a mid- term prediction. The method is applied in a region with a complex and deep seismicity; this is, the Nest of Bucaramanga (Colombia). The seismic catalogue and waveforms for the attenuation analysis are obtained from Ingeominas; the catalogue includes 13629 events with local magnitude ML>3, fulfilling the magnitude completeness conditions. The seismic attenuation data are obtained from waveforms that have been selected between more than 17000 short period vertical seismograms, recorded at Barichara station, which is located right over the seismic nest. Over 3600 of these waveforms fulfil the magnitude completeness conditions, happened at hypocentral distances smaller than 150km and give coda Q fitting values with correlation coefficients r2≥0.7 So, for the time evolution we were able to average over 50 values of Q0

  4. Lower Greenschist Facies Oscillations Across the Brittle-Ductile Transition Induced by Alternating Reaction Softening and Hardening Events

    Science.gov (United States)

    Wintsch, R. P.; Yeh, M.

    2011-12-01

    Reaction textures associated with multiple fabrics in the Red River shear zone show evidence for both brittle and ductile deformation. Rocks on the eastern flank of the shear zone in the Diancang Shan block near Dali, Yunnan Province, China are dominated by porphyritic granodiorites and form the protoliths of the Red River fault rocks. The earliest fault-rocks are cataclasites in which fracture processes broke matrix feldspar grains. Grain-scale brittle fractures and crushed grains are well preserved in the >cm size relic K-feldspar phenocrysts, where multiple fractures are filled with newly precipitated quartz. Progressive deformation has displaced broken K-feldspar fragments into the evolving matrix establishing a cataclastic texture with abundant feldspar porphyroclasts. Ductile deformation is manifest in multiple generations of fabrics that wrap around these broken phenocrysts. The fabrics are defined primarily by muscovite and chlorite that form folia that may exceed the length of a thin section (several cm). Truncations and embayments of these minerals show that earlier magmatic feldspars and biotites have been dissolved and muscovite + chlorite + quartz have crystallized as reaction products. Reaction softening is clearly manifest by the replacement of K-feldspar and the crystallization of quartz as ribbons and muscovite in well aligned folia that define the mylonitic foliation. In some microstructural sites K-feldspar porphyroclasts themselves are truncated and engulfed by muscovite alone. These relationships suggest the simultaneous operation of the locally metasomatic ionic replacement reactions: K-feldspar + Na+ = Albite + K+ , and ΔV = -10% 3K-feldspar + 2H+ = muscovite + 6 quartz + 2K+ and ΔV = -16% 3Albite + K+ + 2H+ = muscovite + 6 quartz + 3Na+. ΔV = - 8% The latter two reactions produce muscovite and quartz, both much weaker than the reactant K-feldspar; these reactions constitute reaction softening. Moreover, the muscovite tends to align in contiguous bands constituting textural softening (Shea and Kronenberg, 1993). These reactions occur without any demonstrable change in temperature, and so produce a shift from brittle to ductile behavior. The reactions also involve a volume loss, such that they will be driven by a high normal stress; thus they are readily driven by a high normal stress. These ductile fabrics are in turn cut by K-feldspar veins that interrupt the mylonitic fabric produced by the above reactions. The K-feldspar veins add K-feldspar to the assemblage and interrupt the mylonitic fabric. Thus these structures constitute both reaction and textural hardening. Finally these may become boudinaged by continued ductile deformation in the mylonitic matrix, thus establishing a late ductile strain event. Together these overprinting textures and microstructures demonstrate two oscillations of brittle to ductile deformation all at lower greenschist facies conditions where only frictional behavior is predicted by experiments.

  5. Fold-and-thrust belt evolution influenced by along and across strike thickness variations: new insights from brittle-ductile centrifuge analogue models

    Science.gov (United States)

    Santolaria Otin, Pablo; Harris, Lyal; Casas, Antonio; Soto, Ruth

    2014-05-01

    Using a new centrifuge analogue modelling approach, 38 models were performed to study the influence of along and across strike thickness variations of a ductile-brittle layered sequence on the kinematics and deformation style of fold-and-thrust belts. Four different series, changing the brittle-ductile thickness ratio in models with i) constant thickness, ii) across strike varying thickness, iii) along strike varying thickness and iv) along and across-strike varying thickness, were performed. The brittle sedimentary cover was simulated by "Moon Sand™", regular fine-grained quartz sand coated by polymer and synthetic rubber binders, allowing layers to be placed vertically in the centrifuge (impossible with normal sand). The ductile décollement (evaporites) was simulated by silicone putty (Crazy Aaron Enterprise's Thinking Putty™). Models were run step by step in a high-acceleration centrifuge attaining 900 g, what allows to drastically reduce the experimental time. In addition to surface observation and serial cross-sections at the end of the models, CT scans portray the progressive 3- and 4-dimensional evolution of several models. With constant thickness, the increase of the brittle-ductile ratio results in the decrease of the number of structures where shortening is accommodated and the development of structures does not follow a linear sequence. Across-strike thickness variations trigger the location of deformation towards the wedge front, precluding the emplacement of structures in the hinterland. Along-strike thickness changes result in the lateral variation of the number of structure and a differential displacement of the deformation front. The occurrence of oblique structures is enhanced in wedges with across and along strike thickness variations where, in addition, rotational domains are observed. Comparison with the South Pyrenean Central Unit, in the Southern Pyrenees, characterized by a west- and southward thinning of the pretectonic Mesozoic series

  6. Brittle-ductile deformation effects on zircon crystal-chemistry and U-Pb ages: an example from the Finero Mafic Complex (Ivrea-Verbano Zone, western Alps)

    Science.gov (United States)

    Langone, Antonio; José Alberto, Padrón-Navarta; Zanetti, Alberto; Mazzucchelli, Maurizio; Tiepolo, Massimo; Giovanardi, Tommaso; Bonazzi, Mattia

    2016-04-01

    correlation between internal zircon structures, chemistry, U-Pb isotope ratios and mylonitic fabric. U-Pb data return highly discordant and variable ages: in particular, the 206Pb/238U ages range from Carboniferous to Triassic within the same zircon grain. The youngest 206Pb/238U data derive from narrow axial stripes oriented parallel or at low angle with respect to the foliation planes. These stripes are characterized by an overall HREE, Y, U and Th enrichment possibly reflecting deformation of the grain in presence of interstitial fluid phases, likely related to a concomitant magmatic activity. Deformation related structures (cracks and fractures) within zircon grains acted as fast-diffusion pathways allowing fluids to modify the geochemistry and isotopic systems of zircon. Our results suggest that fluid-assisted brittle-ductile deformation can severely modify the trace elements and isotopic composition of zircon with unexpected patterns constrained by stress regime. In similar cases, our observations suggest that, for a more appropriate interpretation of the petrologic evolution and age variability, a direct characterization of the internal structures of zircons still placed in their microtextural site is highly recommended.

  7. Development of fluid veins during deformation of fluid-rich rocks close to the brittle-ductile transition: comparison between experimental and physical models.

    Science.gov (United States)

    Michel, Rabinowicz; Micha, Bystricky; Martin, Schmocker; Michael, Toplis; Alexis, Rigo; Hugo, Perfettini

    2010-05-01

    Laboratory experiments generally show that high temperature shear deformation of rocks rich in interstitial fluid leads to the development of long fluid veins parallel to R1 and R2 Riedel directions. This contradicts results of numerous mathematical models suggesting that deformation of a rock with a purely viscous solid rheology triggers fluid banding on planes orthogonal to the direction of maximal extension . High-temperature shear laboratory experiments on a sub-micron flint conducted in an internally heated Paterson apparatus with torsion capabilities (Schmocker et al. 2003; Schmocker 2002) reveal that: (i) flint deforms by grain boundary sliding and dissolution precipitation processes, leading to the development of fluid banding orthogonal to up to a strain of about 0.1-0.2; (ii) R1 and R2 fluid veins form beyond these strains, crossing the first generation of bands formed at low , (iii) during the whole deformation process, the strain rate remains perfectly uniform through the entire sample. In order to understand and rationalize these observations, one dimensional numerical modelling of fluid-rock separation during shear has been performed. The model assumes a constant strain rate and uses the interstitial fluid dependence of pressure-solution viscosity of quartz. When shearing is initiated, fluid and solid pressures are equal (pf = ps). Thereafter in zones of compaction, i.e. zones from which fluid is expelled, pf drops and the solid viscosity rises sharply. Although strain rate is uniform across the bulk sample, local stress sharply rises in the compaction bands but remains low in zones of fluid segregation. Indeed, the model shows that, in the zones of compaction, both the deviatoric stress and the excess pressure (pf - ps) have the same amplitude. Their value exceeds the bulk shear stress necessary to maintain the strain rate constant through the entire sample by a factor of about 5. To maintain a high strain rate during shear, laboratory experiments are generally run with a bulk shear stress close to but lower than the fracturation threshold of the rock. It is thus inferred that the development of R1 and R2 bands simply results from embrittlement of the rock in the zones of compaction in response to the steep increase in local stress and the steep drop in fluid pressure during shearing, while the bulk stress applied to deform the experimental sample remains below the brittle threshold of the rock. Implications of this process for melt segregation in the mantle and fluid percolation in gouges are discussed

  8. 纳米碳酸钙和马来酸酐接枝乙烯-辛烯共聚物弹性体对PA 6脆韧转变及协同增韧的研究%Brittle- ductile transition and synergistic toughening effect of nano CaCO3 and POE-g- MAH on PA 6

    Institute of Scientific and Technical Information of China (English)

    宋波; 黄锐; 魏刚

    2004-01-01

    制备了尼龙6(PA 6)/马来酸酐接枝乙烯-辛烯共聚物弹性体(POE-g-MAH)/纳米CaCO3复合材料.SEM分析表明,部分CaCO3粒子均匀分散在尼龙基质中,部分纳米CaCO3粒子为POE-g-MAH所包覆而形成了"壳-核"结构.随着基体中纳米CaCO3的增加,PA 6/纳米CaCO3/POE-g-MAH发生脆韧转变所需要的弹性体量增加;在韧性断裂时,纳米CaCO3和POE-g-MAH对PA 6的增韧有显著的协同作用.

  9. Brittle-Ductile Relaxation Kinetics of Strained AlGaN/GaN

    Energy Technology Data Exchange (ETDEWEB)

    CHASON, E.; FLORO, JERROLD A.; FOLLSTAEDT, DAVID M.; HAN, JUNG; HEARNE, SEAN JOSEPH; LEE, STEPHEN R.; TSONG, I.S.T.

    1999-10-05

    The authors have directly measured the stress evolution during metal organic chemical vapor deposition of AlGaN/GaN heterostructures on sapphire. In situ stress measurements were correlated with ex situ microstructural analysis to directly determine a critical thickness for cracking and the subsequent relaxation kinetics of tensile-strained Al{sub x}Ga{sub 1{minus}x}N on GaN. Cracks appear to initiate the formation of misfit dislocations at the AlGaN/GaN interface, which account for the majority of the strain relaxation.

  10. Energy transport processes in a brittle ductile intrusive model of the Taupo Volcanic Zone, New Zealand

    Science.gov (United States)

    Weir, Graham J.

    1998-08-01

    The implications of the findings of recent GPS and micro-seismic studies in the Taupo Volcanic Zone (TVZ), New Zealand, on models of processes transporting mass, heat and chemicals are discussed. It is argued that in addition to the well established process of groundwater convection extracting heat and chemicals by interacting with magmatic intrusives under the TVZ, that two other processes may be important. Firstly, the existence of a ductile layer with very low permeability between about 8 to 15 km depth will produce a region of `enhanced conduction' in which very high conductive fluxes of energy arise from a temperature distribution which varies exponentially with depth. Secondly, water may transport up through the ductile layer, as a result of extensional processes in the ductile region. If extension is occurring at about 8 mm/yr, then geothermal heat transfer in the TVZ of about 4200 MW is made up from about 1200 MW from the cooling of intrusives in the brittle region in the upper 8 km; of about an additional 1900 MW of conducted heat entering the brittle region from the ductile region; and about an additional 1100 MW from water transport through the ductile region. Provided this water flow has a chloride concentration similar to that emitted from nearby volcanoes, then the total chloride transport from the TVZ is about 3.5 kg/s, as suggested by average enthalpy to chloride ratios in the TVZ of about 1.2 MJ/g. The present high heat and mass transport processes in the TVZ are assumed to result from the passive filling of volume created from extensional processes under the TVZ, plus conductive and/or convective heating processes below 15 km depth.

  11. Visco-poroelastic damage model for brittle-ductile failure of porous rocks

    Science.gov (United States)

    Lyakhovsky, Vladimir; Zhu, Wenlu; Shalev, Eyal

    2015-04-01

    The coupling between damage accumulation, dilation, and compaction during loading of sandstones is responsible for different structural features such as localized deformation bands and homogeneous inelastic deformation. We distinguish and quantify the role of each deformation mechanism using new mathematical model and its numerical implementation. Formulation includes three different deformation regimes: (I) quasi-elastic deformation characterized by material strengthening and compaction; (II) cataclastic flow characterized by damage increase and compaction; and (III) brittle failure characterized by damage increase, dilation, and shear localization. Using a three-dimensional numerical model, we simulate the deformation behavior of cylindrical porous Berea sandstone samples under different confining pressures. The obtained stress, strain, porosity changes and macroscopic deformation features well reproduce the laboratory results. The model predicts different rock behavior as a function of confining pressures. The quasi-elastic and brittle regimes associated with formation of shear and/or dilatant bands occur at low effective pressures. The model also successfully reproduces cataclastic flow and homogeneous compaction under high pressures. Complex behavior with overlap of common features of all regimes is simulated under intermediate pressures, resulting with localized compaction or shear enhanced compaction bands. Numerical results elucidate three steps in the formation of compaction bands: (1) dilation and subsequent shear localization, (2) formation of shear enhanced compaction band, and (3) formation of pure compaction band.

  12. The transition between shortening and extensional regimes in central Mexico recorded in the tourmaline veins of the Comanja Granite

    Science.gov (United States)

    Angeles-Moreno, Edgar; Nieto-Samaniego, Angel Francisco; Ruiz-González, Francisco Jesús; Levresse, Gilles; Alaniz-Alvarez, Susana Alicia; Olmos Moya, María de Jesús Paulina; Xu, Shunshan; Miranda-Avilés, Raúl

    2017-01-01

    In central Mexico, there is a major angular unconformity separating two lithologic groups. Below the unconformity, the rocks display shortening deformation structures produced by the Laramide orogeny, overprinting those shortening structures there are normal faults related to the Cenozoic Basin and Range tectonics. Above the unconformity, the rocks are affected only by the Basin and Range tectonics, displaying mainly normal faults and in minor amount, lateral-oblique faults. We analyzed the Comanja Granite in the Sierra de Guanajuato, it is a large pluton that contains tourmaline veins. The Granite lacks of the shortening structures that pervasively affected the Mesozoic host-rocks; for this reason, we infer that the granite was formed after the main shortening event. We determined that the emplacement of the Comanja Granite took place between 51.0 ± 0.3 Ma and 49.5 ± 0.8 Ma, and that the tourmaline veins of the granite were formed at ∼51.0 Ma. At the microscopic scale, the tourmaline veins contain three kinds of tourmaline, called T1, T2, and T3, according to the order of their formation. The T1 tourmalines are brown colored and appear affected by brittle-ductile (D1) and brittle (D2) deformations. The cataclasites formed during D2 overprinted the brittle-ductile structures of D1, indicating the transition from deeper to shallower levels. In contrast, T2 and T3 tourmalines were not involved in those deformations. At the outcrop scale, we identified two slickensides in the tourmaline veins. The older, related to D1, is strike-slip with a small thrust component and the younger, related to D2, is normal with oblique components. The T1 tourmalines (which are deformed) were formed before the lateral-thrust faulting, whereas the T2 and T3 tourmalines, which are not deformed, were deposited after the faulting occurred in the veins. Our interpretation is that T1 tourmalines were deposited in the later phases of the Comanja Granite emplacement, with the minimum

  13. Analogue modelling of inclined, brittle-ductile transpression: Testing analytical models through natural shear zones (external Betics)

    Science.gov (United States)

    Barcos, L.; Díaz-Azpiroz, M.; Balanyá, J. C.; Expósito, I.; Jiménez-Bonilla, A.; Faccenna, C.

    2016-07-01

    The combination of analytical and analogue models gives new opportunities to better understand the kinematic parameters controlling the evolution of transpression zones. In this work, we carried out a set of analogue models using the kinematic parameters of transpressional deformation obtained by applying a general triclinic transpression analytical model to a tabular-shaped shear zone in the external Betic Chain (Torcal de Antequera massif). According to the results of the analytical model, we used two oblique convergence angles to reproduce the main structural and kinematic features of structural domains observed within the Torcal de Antequera massif (α = 15° for the outer domains and α = 30° for the inner domain). Two parallel inclined backstops (one fixed and the other mobile) reproduce the geometry of the shear zone walls of the natural case. Additionally, we applied digital particle image velocimetry (PIV) method to calculate the velocity field of the incremental deformation. Our results suggest that the spatial distribution of the main structures observed in the Torcal de Antequera massif reflects different modes of strain partitioning and strain localization between two domain types, which are related to the variation in the oblique convergence angle and the presence of steep planar velocity - and rheological - discontinuities (the shear zone walls in the natural case). In the 15° model, strain partitioning is simple and strain localization is high: a single narrow shear zone is developed close and parallel to the fixed backstop, bounded by strike-slip faults and internally deformed by R and P shears. In the 30° model, strain partitioning is strong, generating regularly spaced oblique-to-the backstops thrusts and strike-slip faults. At final stages of the 30° experiment, deformation affects the entire model box. Our results show that the application of analytical modelling to natural transpressive zones related to upper crustal deformation facilitates to constrain the geometrical parameters of analogue models.

  14. Brittle/Ductile deformation at depth during continental crust eclogitization (Mont-Emilius klippe, Western Internal Alps).

    Science.gov (United States)

    Hertgen, Solenn; Yamato, Philippe; Morales, Luiz; Angiboust, Samuel

    2016-04-01

    Eclogitic rocks are important for understanding tectonics at large scale as they provide key constraints on both the evolution (P-T-t-ɛ paths) and the deformation modes of the crust along the subduction interface. We herein focus our study on eclogitized mafic dykes remnants exposed within granulites from the continental basement silver of the Mt. Emilius klippe (Western Internal Alps, Italy). These eclogites exhibit highly deformed garnetite and clinopyroxenite levels. In some places, these rocks with a ± mylonitic aspect can be found as clasts within meter-thick brecciated fault rocks formed close to metamorphic peak conditions in eclogite facies. Especially, the garnet-rich levels tend to behave in a brittle fashion while deformation within clinopyroxene-rich levels is mostly accommodated by creep. This is evidenced by the presence of elongated grains, subgrain boundaries and intense grain size reduction close to rigid garnets. Crystallographic preferred orientation (CPO) measurements in garnets indicate a quasi-random distribution. In most of the clinopyroxenes levels nevertheless, the CPO is relatively strong, with multiples of uniform distribution varying from 4 to 5.5 (value of 1 is random texture). This CPO is characterized by a strong alignment of poles (001) parallel to the lineation and (100) and [010] distributed along girdles cross-cutting the foliation plane. Our study thus attests that the materials along the subduction interface at P~2.0-2.5 GPa and T~500-550°C can locally be brittle where deformation is classically envisioned as ductile. In addition to this deformation analysis, we present a petrological study of these eclogites, from the outcrop to the microscopic scale, tracking the chemical evolution associated to the observed deformation. Based on all these data, we finally propose a tectono-metamorphic history for these rocks allowing to explain the co-existence of ductile and brittle features developed in the same metamorphic facies, and closely associated to the circulation of metamorphic fluids.

  15. Factors controlling the mode of rift interaction in brittle-ductile coupled systems: A 3D numerical study

    NARCIS (Netherlands)

    Allken, V.; Huismans, R.S.; Thieulot, C.

    2012-01-01

    The way individual faults and rift segments link up is a fundamental aspect of lithosphere extension and continental break-up. Little is known however about the factors that control the selection of the different modes of rift interaction observed in nature. Here we use state-of-the-art large deform

  16. Static assessment of brittle/ductile notched materials: an engineering approach based on the Theory of Critical Distances

    Directory of Open Access Journals (Sweden)

    R. Louks

    2014-10-01

    Full Text Available Engineering components often contain notches, keyways or other stress concentration features. These features raise the stress state in the vicinity of their apex which can lead to unexpected failure of the component. The Theory of Critical Distances has been proven to predict accurate results, but, conventionally, requires two key ingredients to be implemented: the first is a stress-distance curve which can be obtained relatively easily by means of any finite element software, the second is two additional material parameters which are determined by running appropriate experiments. In this novel reformulation, one of these additional parameters, namely the critical distance, can be determined a priori, allowing design engineers to assess components whilst reducing the time and cost of the design process. This paper investigates reformulating the Theory of Critical Distances to be based on two readily available material parameters, i.e., the Ultimate Tensile Strength and the Fracture Toughness. An experimental data base was compiled from the technical literature. The investigated samples had a range of stress concentration features including sharp V-notches to blunt U-notches, and a range of materials that exhibit brittle, quasi-brittle and ductile mechanical behaviour. Each data set was assessed and the prediction error was calculated. The failure predictions were on average 30% conservative, whilst the non-conservative predictions account for less than 10% of the tested data and less than 2% of the non-conservative error results exceed -20%. It is therefore recommended that a safety factor of at least 1.2 is used in the implementation of this version of the Theory of Critical Distances.

  17. Rheological transitions in the middle crust: insights from Cordilleran metamorphic core complexes

    Science.gov (United States)

    Cooper, Frances J.; Platt, John P.; Behr, Whitney M.

    2017-02-01

    High-strain mylonitic rocks in Cordilleran metamorphic core complexes reflect ductile deformation in the middle crust, but in many examples it is unclear how these mylonites relate to the brittle detachments that overlie them. Field observations, microstructural analyses, and thermobarometric data from the footwalls of three metamorphic core complexes in the Basin and Range Province, USA (the Whipple Mountains, California; the northern Snake Range, Nevada; and Ruby Mountains-East Humboldt Range, Nevada), suggest the presence of two distinct rheological transitions in the middle crust: (1) the brittle-ductile transition (BDT), which depends on thermal gradient and tectonic regime, and marks the switch from discrete brittle faulting and cataclasis to continuous, but still localized, ductile shear, and (2) the localized-distributed transition, or LDT, a deeper, dominantly temperature-dependent transition, which marks the switch from localized ductile shear to distributed ductile flow. In this model, brittle normal faults in the upper crust persist as ductile shear zones below the BDT in the middle crust, and sole into the subhorizontal LDT at greater depths.In metamorphic core complexes, the presence of these two distinct rheological transitions results in the development of two zones of ductile deformation: a relatively narrow zone of high-stress mylonite that is spatially and genetically related to the brittle detachment, underlain by a broader zone of high-strain, relatively low-stress rock that formed in the middle crust below the LDT, and in some cases before the detachment was initiated. The two zones show distinct microstructural assemblages, reflecting different conditions of temperature and stress during deformation, and contain superposed sequences of microstructures reflecting progressive exhumation, cooling, and strain localization. The LDT is not always exhumed, or it may be obscured by later deformation, but in the Whipple Mountains, it can be directly

  18. Brittle-tough transitions during crack growth in toughened adhesives

    Science.gov (United States)

    Thoules, Michael

    2008-03-01

    The use of structural adhesives in automotive applications relies on an effective understanding of their performance under crash conditions. In particular, there is considerable potential for mechanics-based modeling of the interaction between an adhesive layer and the adherends, to replace current empirical approaches to design. Since energy dissipation during a crash, mediated by plastic deformation of the structure, is a primary consideration for automotive applications, traditional approaches of fracture mechanics are not appropriate. Cohesive-zone models that use two fracture parameters - cohesive strength and toughness - have been shown to provide a method for quantitative mechanics analysis. Combined numerical and experimental techniques have been developed to deduce the toughness and strength parameters of adhesive layers, allowing qualitative modeling of the performance of adhesive joints. These techniques have been used to study the failure of joints, formed from a toughened adhesive and sheet metal, over a wide range of loading rates. Two fracture modes are observed: quasi-static crack growth and dynamic crack growth. The quasi-static crack growth is associated with a toughened mode of failure; the dynamic crack growth is associated with a more brittle mode of failure. The results of the experiments and analyses indicate that the fracture parameters for quasi-static crack growth in this toughened system are essentially rate independent, and that quasi-static crack growth can occur even at the highest crack velocities. Effects of rate appear to be limited to the ease with which a transition to dynamic fracture could be triggered. This transition appears to be stochastic in nature, and it does not appear to be associated with the attainment of any critical value for crack velocity or loading rate. Fracture-mechanics models exist in the literature for brittle-ductile transitions in rate-dependent polymers, which rely on rate dependent values of toughness

  19. The disproportionation reaction phase transition, mechanical, and lattice dynamical properties of the lanthanum dihydrides under high pressure: A first principles study

    Science.gov (United States)

    Yang, Jin-Wen; Gao, Tao; Gong, Yan-Rong

    2014-06-01

    The pressure-induced disproportionation reaction phase transition, mechanical, and dynamical properties of LaH2 with fluorite structure under high pressure are investigated by performing first-principles calculations using the projector augmented wave (PAW) method. The phase transition of 2LaH2 → LaH + LaH3 obtained from the usual condition of equal enthalpies occurs at the pressure of 10.38 GPa for Perdew-Wang (PW91) functional and 6.05 GPa for Ceperly-Adler (CA) functional, respectively. The result shows that the PW91 functional calculations agree excellently with the experimental finding of 11 GPa of synchrotron radiation (SR) X-ray diffraction (XRD) of Machida et al. and 10 GPa of their PBE functional theoretical result. Three independent single-crystal elastic constants, polycrystalline bulk modulus, shear modulus, Young's modulus, elastic anisotropy, Poisson's ratio, the brittle/ductile characteristics and elastic wave velocities over different directions dependences on pressure are also successfully obtained. Especially, the phonon dispersion curves and corresponding phonon density of states of LaH2 under high pressure are determined systematically using a linear-response approach to density functional perturbation theory (DFPT). Our results demonstrate that LaH2 in fluorite phase can be stable energetically up to 10.38 GPa, stabilized mechanically up to 17.98 GPa, and stabilized dynamically up to 29 GPa, so it may remain a metastable phase above 10.38 GPa up to 29 GPa, these calculated results accord with the recent X-Ray diffraction experimental finding and theoretical predictions of Machida et al.

  20. Applying micromechanic failure models for description of failure modes in the ductile-brittle transition region; Einsatz mikromechanischer Schaedigungsmodelle im sproed-duktilen Uebergangsbereich

    Energy Technology Data Exchange (ETDEWEB)

    Bernauer, G.

    1997-07-01

    The work reported was to examine whether the modified Gurson model and the Beremin model can be applied to the brittle-ductile transition region of a ferritic steel, and whether the material`s behaviour can be characterized with a failure model integrating the two models mentioned above into one. Any possible improvements of this approach were to be found. The report at first gives a brief list of terminology and formulas used. Chapter 3 explains the microscopic processes typically observed in the transition region in connection with the failure modes of ductile fracture and cleavage fracture, and shows possible approaches for modelling. Chapter 4 defines the specimens and materials, and chapter 5 explains the experiments as well as the microscopic analyses of the fracture surfaces. Chapter 6 presents subsequent calculations representing the processes observed. Based on the stress distributions thus derived, the Beremin model is re-examined for further development. Chapter 7 summarizes the results obtained. (orig./CB) [Deutsch] Ziel der Arbeit ist, zu untersuchen, ob das modifizierte Gurson-Modell und das Beremin-Modell im sproed-duktilen Uebergangsbereich eines ferritischen Stahls einsetzbar sind und ob das Werkstoffverhalten mit einem aus beiden Modellen kombinierten Schaedigungsmodell berechnet werden kann. Gegebenenfalls sind Verbesserungen herbeizufuehren. Die vorliegende Arbeit beginnt mit einer kurzen Einfuehrung der verwendeten Begriffe und Formalismen. In Kap. 3 werden die mikroskopischen Vorgaenge bei den im Uebergangsbereich typischerweise auftretenden Versagensarten duktiler Bruch und Spaltbruch vorgestellt und verschiedene Moeglichkeiten ihrer Modellierung aufgezeigt. Nach der Vorstellung des Probenwerkstoffs werden in Kap. 4 die Experimente beschrieben und die mikroskopischen Untersuchungen der Bruchflaechen in Kap. 5 dargestellt. Die Nachrechnungen der Experimente werden in Kap. 6 vorgestellt. Auf der Grundlage der dadurch bereitgestellten

  1. Kinematics of large scale asymmetric folds and associated smaller scale brittle-ductile structures in the Proterozoic Somnur Formation, Pranhita - Godavari valley, south India

    Indian Academy of Sciences (India)

    Gautam Ghosh; Dilip Saha

    2005-04-01

    The development of structural elements and finite strain data are analysed to constrain kinematics of folds and faults at various scales within a Proterozoic fold-and-thrust belt in Pranhita-Godavari basin, south India. The first order structures in this belt are interpreted as large scale buckle folds above a subsurface decollement emphasizing the importance of detachment folding in thin skinned deformation of a sedimentary prism lying above a gneissic basement. That the folds have developed through fixed-hinge buckling is constrained by the nature of variation of mesoscopic fabric over large folds and finite strain data. Relatively low, irrotational °attening strain (X:Z - 3.1-4.8, k > 1) are associated with zones of near upright early mesoscopic folds and cleavage, whereas large flattening strain (X:Z - 3.9-7.3, k > 1) involving noncoaxiality are linked to domains of asymmetric, later inclined folds, faults and intense cleavage on the hanging wall of thrusts on the flanks of large folds. In the latter case, the bulk strain can be factorized to components of pure shear and simple shear with a maximum shearing strain of 3. The present work reiterates the importance of analysis of minor structures in conjunction with strain data to unravel the kinematic history of fold-and-thrust belts developed at shallow crustal level.

  2. The effect of energy feedbacks on continental strength.

    Science.gov (United States)

    Regenauer-Lieb, Klaus; Weinberg, Roberto F; Rosenbaum, Gideon

    2006-07-06

    The classical strength profile of continents is derived from a quasi-static view of their rheological response to stress--one that does not consider dynamic interactions between brittle and ductile layers. Such interactions result in complexities of failure in the brittle-ductile transition and the need to couple energy to understand strain localization. Here we investigate continental deformation by solving the fully coupled energy, momentum and continuum equations. We show that this approach produces unexpected feedback processes, leading to a significantly weaker dynamic strength evolution. In our model, stress localization focused on the brittle-ductile transition leads to the spontaneous development of mid-crustal detachment faults immediately above the strongest crustal layer. We also find that an additional decoupling layer forms between the lower crust and mantle. Our results explain the development of decoupling layers that are observed to accommodate hundreds of kilometres of horizontal motions during continental deformation.

  3. Sustainable Transition

    DEFF Research Database (Denmark)

    Hansen, Ole Erik; Søndergård, Bent

    2014-01-01

    transition processes. Where. Addresses design processes aimed at sustainable transition enacted in complex social settings, socio-technical systems involving many different actors and agendas. How. The chapter outlines a conceptual and analytic framework for a reflexive design practice for sustainability...... including the perspective of structural changes (transition of socio-technical systems and social practices) and Design as metadesign; an reflexivity on contextual framework of the design practice (regimes/design spaces)....

  4. Phase transitions

    CERN Document Server

    Solé, Ricard V

    2011-01-01

    Phase transitions--changes between different states of organization in a complex system--have long helped to explain physics concepts, such as why water freezes into a solid or boils to become a gas. How might phase transitions shed light on important problems in biological and ecological complex systems? Exploring the origins and implications of sudden changes in nature and society, Phase Transitions examines different dynamical behaviors in a broad range of complex systems. Using a compelling set of examples, from gene networks and ant colonies to human language and the degradation o

  5. Development of the asperity-matrix structure in fault zones: a model for strength reduction and generation of earthquakes

    Science.gov (United States)

    Takeshita, T.

    2014-12-01

    Seismologists have now believed that the fault interface is characterized by the asperity-matrix structure, where the upper and lower plates are strongly coupled at the asperity, and the matrix, which surrounds the asperity, is deformed by creeping. Earthquakes are generated by dynamic rupture only in the non-creeping hard asperity, where the strain energy is accumulated if the asperity and matrix are mechanically coupled to a certain degree. In this presentation, we will argue that this structure is developed as brittle fracturing proceeds aided by dissolution-precipitation creep in particular at the brittle-ductile transition zone, which leads to the strength reduction and seimogenesis in both crust and subduction zones. We have been studying deformation processes and mechanisms in rocks at brittle-ductile transition conditions, based on microstructural analyses in naturally deformed rocks. For example, we reported that pervasive micro-faulting in the high-P/T Sambagawa quartz schist at brittle-ductile transition conditions, where a volume fraction of micro-shear zones consisting of both very-fine grained dynamically recrystallized quartz and white mica increased with increasing deformation (Takeshita and El-Fakharani, 2013). We believe that the resultant structure, "undeformed lenses surrounded by microshear zones" can be correlated with the asperity-matrix structure in the thin section scale, which could have occurred in the mesoscopic to macroscopic scales (cf. Schrank et al., 2008). It is inferred that the rocks became softened with increasing volume fraction of micro-shear zones, because dissolution-precipitation creep could have occurred at low differential stresses in the sheared zones. Further, cataclasites were formed along the Median Tectonic Line in the Cretaceous to Paleogene, where new minerals precipitated from fluids in the space created by fracturing at the conditions of brittle-ductile transition. The fracturing was accompanied by element

  6. Tessellations & Transitions.

    Science.gov (United States)

    Cassidy, Joan

    1998-01-01

    Describes two sixth-grade lessons on the work of M. C. Escher: (1) the first lesson instructs students on tessellations, or tiles that interlock in a repeated pattern; (2) the second lesson explores Escher's drawings of transitions from two- to three-dimensional space. (DSK)

  7. Transition Operators

    CERN Document Server

    Alcock-Zeilinger, Judith

    2016-01-01

    In this paper, we give a generic algorithm of the transition operators between Hermitian Young projection operators corresponding to equivalent irreducible representations of SU(N), using the compact expressions of Hermitian Young projection operators derived in a companion paper. We show that the Hermitian Young projection operators together with their transition operators constitute a fully orthogonal basis for the algebra of invariants of $V^{\\otimes m}$ that exhibits a systematically simplified multiplication table. We discuss the full algebra of invariants over $V^{\\otimes 3}$ and $V^{\\otimes 4}$ as explicit examples. In our presentation we make use of various standard concepts such as Young projection operators, Clebsch-Gordan operators, and invariants (in birdtrack notation). We tie these perspectives together and use them to shed light on each other.

  8. Transit space

    DEFF Research Database (Denmark)

    Raahauge, Kirsten Marie

    2008-01-01

    This article deals with representations of one specific city, Århus, Denmark, especially its central district. The analysis is based on anthropological fieldwork conducted in Skåde Bakker and Fedet, two well-off neighborhoods. The overall purpose of the project is to study perceptions of space...... and the interaction of cultural, social, and spatial organizations, as seen from the point of view of people living in Skåde Bakker and Fedet. The focus is on the city dwellers’ representations of the central district of Århus with specific reference to the concept of transit space. When applied to various Århusian...

  9. Conformational Transitions

    Science.gov (United States)

    Czerminski, Ryszard; Roitberg, Adrian; Choi, Chyung; Ulitsky, Alexander; Elber, Ron

    1991-10-01

    Two computational approaches to study plausible conformations of biological molecules and the transitions between them are presented and discussed. The first approach is a new search algorithm which enhances the sampling of alternative conformers using a mean field approximation. It is argued and demonstrated that the mean field approximation has a small effect on the location of the minima. The method is a combination of the LES protocol (Locally Enhanced Sampling) and simulated annealing. The LES method was used in the past to study the diffusion pathways of ligands from buried active sites in myoglobin and leghemoglobin to the exterior of the protein. The present formulation of LES and its implementation in a Molecular Dynamics program is described. An application for side chain placement in a tetrapeptide is presented. The computational effort associated with conformational searches using LES grows only linearly with the number of degrees of freedom, whereas in the exact case the computational effort grows exponentially. Such saving is of course associated with a mean field approximation. The second branch of studies pertains to the calculation of reaction paths in large and flexible biological systems. An extensive mapping of minima and barriers for two different tetrapeptides is calculated from the known minima and barriers of alanine tetrapeptide which we calculated recently.1 The tetrapeptides are useful models for the formation of secondary structure elements since they are the shortest possible polymers of this type which can still form a complete helical turn. The tetrapeptides are isobutyryl-val(χ1=60)-ala-ala and isobutyryl-val(χ1=-60)-ala-ala. Properties of the hundreds of minima and of the hundreds intervening barriers are discussed. Estimates for thermal transition times between the many conformers (and times to explore the complete phase space) are calculated and compared. It is suggested that the most significant effect of the side chain size is

  10. PyTransit: Transit light curve modeling

    Science.gov (United States)

    Parviainen, Hannu

    2015-05-01

    PyTransit implements optimized versions of the Giménez and Mandel & Agol transit models for exoplanet transit light-curves. The two models are implemented natively in Fortran with OpenMP parallelization, and are accessed by an object-oriented python interface. PyTransit facilitates the analysis of photometric time series of exoplanet transits consisting of hundreds of thousands of data points, and of multipassband transit light curves from spectrophotometric observations. It offers efficient model evaluation for multicolour observations and transmission spectroscopy, built-in supersampling to account for extended exposure times, and routines to calculate the projected planet-to-star distance for circular and eccentric orbits, transit durations, and more.

  11. Geochronology Constraints on Transformation Age from Ductile to Brittle Deformation of the Shangma Fault and Its Tectonic Significance, Dabieshan, Central China

    Institute of Scientific and Technical Information of China (English)

    Wang Guocan; Wang Pu; Liu Chao; Wang An; Ye Runqing

    2008-01-01

    By a detailed investigation of geometry and kinematics of the Shangma (商麻) fault in Dabieshan (大别山),three different crust levels of extension movement have been recognized in sequence from the deep to the shallow:① low-angle ductile detachment shearing with top to the NW; ② low-angle normal fault with top to the NW or NWW in brittle or brittle-ductile transition domain; ③high-angle brittle normal fault with top to the W or NWW. Two samples were chosen for zircon U-Pb age dating to constrain the activity age of the Shangma fault. A bedding intrusive granitoid pegmatite vein that is parallel to the foliation of the low-angle ductile detachment shear zone of the country rock exhibits a lotus-joint type of boudinage deformation,showing syn-tectonic emplacing at the end of the ductile deformation period and deformation in the brittle-ductile transition domain. The zircon U-Pb dating of this granitoid pegmatite vein gives an age of (125.9±4.2) Ma,which expresses the extension in the brittle-ductile transition domain of the Shangma fault. The other sample,which is collected from a granite pluton cutting the foliation of the low-angle ductile detachment shear zone, gives a zircon U-Pb age of (118.8±4.1) Ma,constraining the end of the ductile detachment shearing. Then the transformation age from ductile to brittle deformation can be constrained between 126-119 Ma.Combined with the previous researches,the formation of the Luotian (罗田) dome,which is located to the east of the Shangma fault,can beconstrained during 150-126 Ma. This study gives a new time constraint to the evolution of the Dabie orogenic belt.

  12. High Speed Lapping of SiC Ceramic Material with Solid (Fixed) Abrasives

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; YANG Xin-hong; SHANG Chun-min; HU Xiao-yong; HU Zhong-hui

    2005-01-01

    An experimental investigation is carried out to machine SiC ceramic material through the method of high speed plane lapping with solid(fixed) abrasives after the critical condition of brittle-ductile transition is theoretically analyzed. The results show that the material removal mechanism and the surface roughness are chiefly related to the granularity of abrasives for brittle materials such as SiC ceramic. It is easily realized to machine SiC ceramic in the ductile mode using W3.5 grit and a high efficiency, low cost and smooth surface with a surface roughness of Ra 2.4nm can be achieved.

  13. Electronic hybridisation implications for the damage-tolerance of thin film metallic glasses

    Science.gov (United States)

    Schnabel, Volker; Jaya, B. Nagamani; Köhler, Mathias; Music, Denis; Kirchlechner, Christoph; Dehm, Gerhard; Raabe, Dierk; Schneider, Jochen M.

    2016-01-01

    A paramount challenge in materials science is to design damage-tolerant glasses. Poisson’s ratio is commonly used as a criterion to gauge the brittle-ductile transition in glasses. However, our data, as well as results in the literature, are in conflict with the concept of Poisson’s ratio serving as a universal parameter for fracture energy. Here, we identify the electronic structure fingerprint associated with damage tolerance in thin film metallic glasses. Our correlative theoretical and experimental data reveal that the fraction of bonds stemming from hybridised states compared to the overall bonding can be associated with damage tolerance in thin film metallic glasses. PMID:27819318

  14. The Managerial Transition.

    Science.gov (United States)

    Kneeland, Steven J.

    1980-01-01

    Having identified the problem of managerial transition in a previous article (CE 510 277), the author outlines a strategy for change which includes performance appraisal, definition of the management structure, and counselling for the individual in transition. (SK)

  15. Transitivity of Preferences

    Science.gov (United States)

    Regenwetter, Michel; Dana, Jason; Davis-Stober, Clintin P.

    2011-01-01

    Transitivity of preferences is a fundamental principle shared by most major contemporary rational, prescriptive, and descriptive models of decision making. To have transitive preferences, a person, group, or society that prefers choice option "x" to "y" and "y" to "z" must prefer "x" to "z". Any claim of empirical violations of transitivity by…

  16. Transitive spaces of operators

    CERN Document Server

    Davidson, K R; Radjavi, H

    2007-01-01

    We investigate algebraic and topological transitivity and, more generally, k-transitivity for linear spaces of operators. In finite dimensions, we determine minimal dimensions of k-transitive spaces for every k, and find relations between the degree of transitivity of a product or tensor product on the one hand and those of the factors on the other. We present counterexamples to some natural conjectures. Some infinite dimensional analogues are discussed. A simple proof is given of Arveson's result on the weak-operator density of transitive spaces that are masa bimodules.

  17. Transition Theory – Sustainable Transition of Socio-Technical Systems

    DEFF Research Database (Denmark)

    Søndergård, Bent; Holm, Jesper; Stauning, Inger

    2015-01-01

    Theories of transition management, transition studies and social practise theory Applied to studies of hosuing and construction......Theories of transition management, transition studies and social practise theory Applied to studies of hosuing and construction...

  18. The role of rheology, crustal structures and lithology in the seismicity distribution of the northern Apennines

    Science.gov (United States)

    Chiaraluce, L.; Barchi, M. R.; Carannante, S.; Collettini, C.; Mirabella, F.; Pauselli, C.; Valoroso, L.

    2017-01-01

    The Northern Apennines of Italy is a unique area to study active crustal processes due to the availability of high-resolution subsurface geology (deep borehole and seismic profiles) and seismicity (back-ground and seismic sequences) data. In this work we have investigated the relationship between crustal structures and lithologies, rheological profiles and seismicity cut-off by constructing three integrated profiles across the Umbria-Marche Apennines. At first approximation we observe a good correspondence between the background seismicity cut-off and the modelled brittle ductile transition (BDT): 90% of the seismic activity is located above the transition. In the area characterized by active extension, where the majority of the seismicity is occurring, most of the crustal earthquakes are confined within the brittle layer at depth rheology and therefore the position of the brittle ductile transition exerts a role at regional scale for the occurrence of crustal seismicity, however crustal structures and lithology play the major role at a more local scale and therefore they need to be considered for a better understanding of earthquake distribution within the seismogenic layer.

  19. Predictability of Critical Transitions

    CERN Document Server

    Zhang, Xiaozhu; Hallerberg, Sarah

    2015-01-01

    Critical transitions in multistable systems have been discussed as models for a variety of phenomena ranging from the extinctions of species to socio-economic changes and climate transitions between ice-ages and warm-ages. From bifurcation theory we can expect certain critical transitions to be preceded by a decreased recovery from external perturbations. The consequences of this critical slowing down have been observed as an increase in variance and autocorrelation prior to the transition. However especially in the presence of noise it is not clear, whether these changes in observation variables are statistically relevant such that they could be used as indicators for critical transitions. In this contribution we investigate the predictability of critical transitions in conceptual models. We study the the quadratic integrate-and-fire model and the van der Pol model, under the influence of external noise. We focus especially on the statistical analysis of the success of predictions and the overall predictabil...

  20. Gravitationally induced quantum transitions

    Science.gov (United States)

    Landry, A.; Paranjape, M. B.

    2016-06-01

    In this paper, we calculate the probability for resonantly inducing transitions in quantum states due to time-dependent gravitational perturbations. Contrary to common wisdom, the probability of inducing transitions is not infinitesimally small. We consider a system of ultracold neutrons, which are organized according to the energy levels of the Schrödinger equation in the presence of the Earth's gravitational field. Transitions between energy levels are induced by an oscillating driving force of frequency ω . The driving force is created by oscillating a macroscopic mass in the neighborhood of the system of neutrons. The neutron lifetime is approximately 880 sec while the probability of transitions increases as t2. Hence, the optimal strategy is to drive the system for two lifetimes. The transition amplitude then is of the order of 1.06 ×10-5, and hence with a million ultracold neutrons, one should be able to observe transitions.

  1. Gravitationally induced quantum transitions

    CERN Document Server

    Landry, A

    2016-01-01

    In this letter, we calculate the probability for resonantly induced transitions in quantum states due to time dependent gravitational perturbations. Contrary to common wisdom, the probability of inducing transitions is not infinitesimally small. We consider a system of ultra cold neutrons (UCN), which are organized according to the energy levels of the Schr\\"odinger equation in the presence of the earth's gravitational field. Transitions between energy levels are induced by an oscillating driving force of frequency $\\omega$. The driving force is created by oscillating a macroscopic mass in the neighbourhood of the system of neutrons. The neutrons decay in 880 seconds while the probability of transitions increase as $t^2$. Hence the optimal strategy is to drive the system for 2 lifetimes. The transition amplitude then is of the order of $1.06\\times 10^{-5}$ hence with a million ultra cold neutrons, one should be able to observe transitions.

  2. Turning Forbidden Transitions into Dominant Transitions

    CERN Document Server

    Rivera, Nicholas; Soljacic, Marin

    2016-01-01

    Surface phonon polaritons are hybrid modes of photons and optical phonons that can propagate on the surface of a polar dielectric. In this work, we show that the precise combination of confinement and bandwidth offered by surface phonon polaritons allows for the ability to take forbidden transitions and turn them into the primary means by which an electron emits light. We show that high-order multipolar transitions and two-photon emission processes can be over an order of magnitude faster than competing dipole transitions, as opposed to being as much as eight to ten orders of magnitude slower in free space. Our results have direct implications for the design of fundamentally new types of emitters in the mid and far IR: ones which prefer to change their angular momentum by large amounts and also ones that prefer to emit a relatively broad spectrum of entangled photons - potentially allowing for new sources of both single and multiple photons.

  3. Transit Benefit Program Data -

    Data.gov (United States)

    Department of Transportation — This data set contains information about any US government agency participating in the transit benefits program, funding agreements, individual participating Federal...

  4. Origins of evolutionary transitions

    Indian Academy of Sciences (India)

    Ellen Clarke

    2014-04-01

    An `evolutionary transition in individuality’ or `major transition’ is a transformation in the hierarchical level at which natural selection operates on a population. In this article I give an abstract (i.e. level-neutral and substrate-neutral) articulation of the transition process in order to precisely understand how such processes can happen, especially how they can get started.

  5. Matter in transition

    Science.gov (United States)

    Anderson, Lara B.; Gray, James; Raghuram, Nikhil; Taylor, Washington

    2016-04-01

    We explore a novel type of transition in certain 6D and 4D quantum field theories, in which the matter content of the theory changes while the gauge group and other parts of the spectrum remain invariant. Such transitions can occur, for example, for SU(6) and SU(7) gauge groups, where matter fields in a three-index antisymmetric representation and the fundamental representation are exchanged in the transition for matter in the two-index antisymmetric representation. These matter transitions are realized by passing through superconformal theories at the transition point. We explore these transitions in dual F-theory and heterotic descriptions, where a number of novel features arise. For example, in the heterotic description the relevant 6D SU(7) theories are described by bundles on K3 surfaces where the geometry of the K3 is constrained in addition to the bundle structure. On the F-theory side, non-standard representations such as the three-index antisymmetric representation of SU( N) require Weierstrass models that cannot be realized from the standard SU( N) Tate form. We also briefly describe some other situations, with groups such as Sp(3), SO(12), and SU(3), where analogous matter transitions can occur between different representations. For SU(3), in particular, we find a matter transition between adjoint matter and matter in the symmetric representation, giving an explicit Weierstrass model for the F-theory description of the symmetric representation that complements another recent analogous construction.

  6. Transition Texture Synthesis

    Institute of Scientific and Technical Information of China (English)

    Yueh-Yi Lai; Wen-Kai Tai

    2008-01-01

    Synthesis of transition textures is essential for displaying visually acceptable appearances on a terrain. This investigation presents a modified method for synthesizing the transition texture to be tiled on a terrain. All transition pattern types are recognized for a number of input textures. The proposed modified patch-based sampling texture synthesis approach, using the extra feature map of the input source and target textures for patch matching, can synthesize any transition texture on a succession pattern by initializing the output texture using a portion of the source texture enclosed in a transition cut. The transition boundary is further enhanced to improve the visual effect by tracing out the integral texture elements. Either the Game of Life model or Wang tiles method are exploited to present a good-looking profile of successions on a terrain for tiling transition textures. Experimental results indicate that the proposed method requires few input textures, yet synthesizes numerous tileable transition textures, which are useful for obtaining a vivid appearance of a terrain.

  7. Transition radiation by neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Ioannisian, A.N., E-mail: ara.ioannisyan@cern.ch [Yerevan Physics Institute, Alikhanian Br. 2, 375036 Yerevan (Armenia); CERN, Theory Division, CH-1211 Geneva 23 (Switzerland); Institute for Theoretical Physics and Modeling, 375036 Yerevan (Armenia); Ioannisian, D.A. [Yerevan Physics Institute, Alikhanian Br. 2, 375036 Yerevan (Armenia); Institute for Theoretical Physics and Modeling, 375036 Yerevan (Armenia); Physics Department, Yerevan State University, 1 Alex Manoogian (Armenia); Kazarian, N.A. [Institute for Theoretical Physics and Modeling, 375036 Yerevan (Armenia)

    2011-08-19

    We calculate the transition radiation process {nu}{yields}{nu}{gamma} at an interface of two media. The neutrinos are taken to be with only standard-model couplings. The medium fulfills the dual purpose of inducing an effective neutrino-photon vertex and of modifying the photon dispersion relation. The transition radiation occurs when at least one of those quantities have different values in different media. The neutrino mass is ignored due to its negligible contribution. We present a result for the probability of the transition radiation which is both accurate and analytic. For E{sub {nu}=}1 MeV neutrino crossing polyethylene-vacuum interface the transition radiation probability is about 10{sup -39} and the energy intensity is about 10{sup -34} eV. At the surface of the neutron stars the transition radiation probability may be {approx}10{sup -20}. Our result is by the three orders of magnitude larger than those of previous calculations.

  8. Transition radiation by neutrinos

    Science.gov (United States)

    Ioannisian, A. N.; Ioannisian, D. A.; Kazarian, N. A.

    2011-08-01

    We calculate the transition radiation process ν→νγ at an interface of two media. The neutrinos are taken to be with only standard-model couplings. The medium fulfills the dual purpose of inducing an effective neutrino-photon vertex and of modifying the photon dispersion relation. The transition radiation occurs when at least one of those quantities have different values in different media. The neutrino mass is ignored due to its negligible contribution. We present a result for the probability of the transition radiation which is both accurate and analytic. For Eν=1 MeV neutrino crossing polyethylene-vacuum interface the transition radiation probability is about 10 and the energy intensity is about 10 eV. At the surface of the neutron stars the transition radiation probability may be ˜10. Our result is by the three orders of magnitude larger than those of previous calculations.

  9. High strain-rate deformation fabrics characterize a kilometers-thick Paleozoic fault zone in the Eastern Sierras Pampeanas, central Argentina

    Science.gov (United States)

    Whitmeyer, Steven J.; Simpson, Carol

    2003-06-01

    High strain rate fabrics that transgress a crustal depth range of ca. 8-22 km occur within a major Paleozoic fault zone along the western margin of the Sierras de Córdoba, central Argentina. The NNW-striking, east-dipping 'Tres Arboles' fault zone extends for at least 250 km and separates two metamorphic terranes that reached peak temperatures in the middle Cambrian and Ordovician, respectively. Exposed fault zone rocks vary from a 16-km-thickness of ultramylonite and mylonite in the southern, deepest exposures to 520 °C. Reaction-enhanced grain size reduction and grain boundary sliding were the predominant deformation mechanisms in these high strain rate rocks. Ultramylonites in the intermediate depth section also contain evidence for grain boundary sliding and diffusional mass transfer, although overprinted by late stage chlorite. In the shallowest exposed section, rocks were deformed at or near to the brittle-ductile transition to produce mylonite, cataclasite, shear bands and pseudotachylyte. The overall structure of the Tres Arboles zone is consistent with existing fault zone models and suggests that below the brittle-ductile transition, strain compatibility may be accommodated through very thick zones of high temperature ultramylonite.

  10. The uniaxial compressive strength of the Arctic summer sea ice

    Institute of Scientific and Technical Information of China (English)

    HAN Hongwei; LI Zhijun; HUANG Wenfeng; LU Peng; LEI Ruibo

    2015-01-01

    The results on the uniaxial compressive strength of Arctic summer sea ice are presented based on the sam-ples collected during the fifth Chinese National Arctic Research Expedition in 2012 (CHINARE-2012). Exper-imental studies were carried out at different testing temperatures (−3, −6 and −9°C), and vertical samples were loaded at stress rates ranging from 0.001 to 1 MPa/s. The temperature, density, and salinity of the ice were measured to calculate the total porosity of the ice. In order to study the effects of the total porosity and the density on the uniaxial compressive strength, the measured strengths for a narrow range of stress rates from 0.01 to 0.03 MPa/s were analyzed. The results show that the uniaxial compressive strength decreases linearly with increasing total porosity, and when the density was lower than 0.86 g/cm3, the uniaxial com-pressive strength increases in a power-law manner with density. The uniaxial compressive behavior of the Arctic summer sea ice is sensitive to the loading rate, and the peak uniaxial compressive strength is reached in the brittle-ductile transition range. The dependence of the strength on the temperature shows that the calculated average strength in the brittle-ductile transition range, which was considered as the peak uniaxial compressive strength, increases steadily in the temperature range from −3 to −9°C.

  11. Predictability of critical transitions

    Science.gov (United States)

    Zhang, Xiaozhu; Kuehn, Christian; Hallerberg, Sarah

    2015-11-01

    Critical transitions in multistable systems have been discussed as models for a variety of phenomena ranging from the extinctions of species to socioeconomic changes and climate transitions between ice ages and warm ages. From bifurcation theory we can expect certain critical transitions to be preceded by a decreased recovery from external perturbations. The consequences of this critical slowing down have been observed as an increase in variance and autocorrelation prior to the transition. However, especially in the presence of noise, it is not clear whether these changes in observation variables are statistically relevant such that they could be used as indicators for critical transitions. In this contribution we investigate the predictability of critical transitions in conceptual models. We study the quadratic integrate-and-fire model and the van der Pol model under the influence of external noise. We focus especially on the statistical analysis of the success of predictions and the overall predictability of the system. The performance of different indicator variables turns out to be dependent on the specific model under study and the conditions of accessing it. Furthermore, we study the influence of the magnitude of transitions on the predictive performance.

  12. Martensitic phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Petry, W.; Neuhaus, J. [Techn. Universitaet Muenchen, Physik Department E13, Munich (Germany)

    1996-11-01

    Many elements transform from a high temperature bcc phase to a more dense packed temperature phase. The great majority of these transitions are of 1st order, displacive and reconstructive. The lattice potentials which govern these martensitic transitions can be probed by inelastic neutron scattering, thereby answering fundamental questions like : Will the transition be announced by dynamical or static fluctuations? What are the trajectories for the displacements needed for the transformation? Does the vibrational entropy stabilize the high temperature phase? Are the unusual transport properties in these materials related to their ability to transform? (author) 17 figs., 1 tab., 46 refs.

  13. Anomalous radiative transitions

    CERN Document Server

    Ishikawa, Kenzo; Tobita, Yutaka

    2014-01-01

    Anomalous transitions involving photons derived by many-body interaction of the form, $\\partial_{\\mu} G^{\\mu}$, in the standard model are studied. This does not affect the equation of motion in the bulk, but makes wave functions modified, and causes the unusual transition characterized by the time-independent probability. In the transition probability at a time-interval T expressed generally in the form $P=T \\Gamma_0 +P^{(d)}$, now with $\\Gamma_0=0, P^{(d)} \

  14. Transition nozzle combustion system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won-Wook; McMahan, Kevin Weston; Maldonado, Jaime Javier

    2016-11-29

    The present application provides a combustion system for use with a cooling flow. The combustion system may include a head end, an aft end, a transition nozzle extending from the head end to the aft end, and an impingement sleeve surrounding the transition nozzle. The impingement sleeve may define a first cavity in communication with the head end for a first portion of the cooling flow and a second cavity in communication with the aft end for a second portion of the cooling flow. The transition nozzle may include a number of cooling holes thereon in communication with the second portion of the cooling flow.

  15. Variational Transition State Theory

    Energy Technology Data Exchange (ETDEWEB)

    Truhlar, Donald G. [Univ. of Minnesota, Minneapolis, MN (United States)

    2016-09-29

    This is the final report on a project involving the development and applications of variational transition state theory. This project involved the development of variational transition state theory for gas-phase reactions, including optimized multidimensional tunneling contributions and the application of this theory to gas-phase reactions with a special emphasis on developing reaction rate theory in directions that are important for applications to combustion. The development of variational transition state theory with optimized multidimensional tunneling as a useful computational tool for combustion kinetics involved eight objectives.

  16. Transition feeding of sows

    DEFF Research Database (Denmark)

    Theil, Peter Kappel

    2015-01-01

    becomes catabolic due to the high priority of milk production and to current feeding practices. Indeed, feed is changed from a gestation to a lactation diet for most sows and the feed supply typically goes from a restricted supply to an ad libitum allowance. In addition, transition sows are often exposed...... the first few days of lactation, and milk yield increases throughout the transition period and becomes the most important determinant of nutrient requirements. Thus, nutrient requirements of transition sows are affected by many intrinsic factors and these requirements change rapidly, yet, sow feeding...... practices do not acknowledge these changes. Development of new feeding strategies specifically adapted for the transition sow is likely of importance to match the rapid changes in nutrient requirements....

  17. Melting of Transition Metals

    Energy Technology Data Exchange (ETDEWEB)

    Ross, M; Japel, S; Boehler, R

    2005-04-11

    We review the transition melting studies carried out at Mainz, and describe a recently developed model used to explain that the relatively low melting slopes are due to the partially filled d-bands, and the persistence of the pressure induced s-d transition. The basic tenets of the model have now been reconfirmed by new measurements for Cu and Ni. The measurements show that Cu which has a filled 3d-band, has a melt slope that is about 2.5 greater than its neighbor Ni. In the case of Mo, the apparent discrepancy of DAC melting measurements with shock melting can be explained by accounting for the change in melt slope due to the bcc-cp transition observed in the shock studies. The Fe melt curve is revisited. The possible relevance of the Jahn-Teller effect and recently observed transition metal melts with Icosahedral Short-Range Order (ISRO) is discussed.

  18. Transitivity on Weierstrass points

    CERN Document Server

    Laing, Zoe

    2010-01-01

    We look for Riemann surfaces whose automorphism group acts transitively on the Weierstrass points. We concentrate on hyperelliptic surfaces, surfaces with PSL(2, q) as automorphism group, Platonic surfaces and Fermat curves.

  19. Transiting Exoplanets with JWST

    CERN Document Server

    Seager, S; Valenti, J A

    2008-01-01

    The era of exoplanet characterization is upon us. For a subset of exoplanets -- the transiting planets -- physical properties can be measured, including mass, radius, and atmosphere characteristics. Indeed, measuring the atmospheres of a further subset of transiting planets, the hot Jupiters, is now routine with the Spitzer Space Telescope. The James Webb Space Telescope (JWST) will continue Spitzer's legacy with its large mirror size and precise thermal stability. JWST is poised for the significant achievement of identifying habitable planets around bright M through G stars--rocky planets lacking extensive gas envelopes, with water vapor and signs of chemical disequilibrium in their atmospheres. Favorable transiting planet systems, are, however, anticipated to be rare and their atmosphere observations will require tens to hundreds of hours of JWST time per planet. We review what is known about the physical characteristics of transiting planets, summarize lessons learned from Spitzer high-contrast exoplanet m...

  20. Phase transitions modern applications

    CERN Document Server

    Gitterman, Moshe

    2014-01-01

    This book provides a comprehensive review of the theory of phase transitions and its modern applications, based on the five pillars of the modern theory of phase transitions i.e. the Ising model, mean field, scaling, renormalization group and universality. This expanded second edition includes, along with a description of vortices and high temperature superconductivity, a discussion of phase transitions in chemical reaction and moving systems. The book covers a close connection between phase transitions and small world phenomena as well as scale-free systems such as the stock market and the Internet. Readership: Scientists working in different fields of physics, chemistry, biology and economics as well as teaching material for undergraduate and graduate courses.

  1. Oligocyclopentadienyl transition metal complexes

    Energy Technology Data Exchange (ETDEWEB)

    de Azevedo, Cristina G.; Vollhardt, K. Peter C.

    2002-01-18

    Synthesis, characterization, and reactivity studies of oligocyclopentadienyl transition metal complexes, namely those of fulvalene, tercyclopentadienyl, quatercyclopentadienyl, and pentacyclopentadienyl(cyclopentadienyl) are the subject of this account. Thermal-, photo-, and redox chemistries of homo- and heteropolynuclear complexes are described.

  2. Superconductivity in transition metals.

    Science.gov (United States)

    Slocombe, Daniel R; Kuznetsov, Vladimir L; Grochala, Wojciech; Williams, Robert J P; Edwards, Peter P

    2015-03-13

    A qualitative account of the occurrence and magnitude of superconductivity in the transition metals is presented, with a primary emphasis on elements of the first row. Correlations of the important parameters of the Bardeen-Cooper-Schrieffer theory of superconductivity are highlighted with respect to the number of d-shell electrons per atom of the transition elements. The relation between the systematics of superconductivity in the transition metals and the periodic table high-lights the importance of short-range or chemical bonding on the remarkable natural phenomenon of superconductivity in the chemical elements. A relationship between superconductivity and lattice instability appears naturally as a balance and competition between localized covalent bonding and so-called broken covalency, which favours d-electron delocalization and superconductivity. In this manner, the systematics of superconductivity and various other physical properties of the transition elements are related and unified.

  3. Transitions in Energy Use

    OpenAIRE

    Grubler, A.

    2004-01-01

    Patterns of energy use have changed dramatically since the onset of the industrial revolution in terms of both energy quantities and energy quality. These changing patterns of energy use, where energy quantities and quality interact in numerous important ways, are referred to in this article as energy transitions and are described from a historical perspective as well as through future scenarios. Far from being completed, many of these transitions are continuing to unfold in industrial and de...

  4. The SAT phase transition

    Institute of Scientific and Technical Information of China (English)

    许可; 李未

    1999-01-01

    Phase transition is an important feature of SAT problem. For random k-SAT model, it is proved that as r(ratio of clauses to variables) increases, the structure of solutions will undergo a sudden change like satisfiability phase transition when r reaches a threshold point (r=rcr). This phenomenon shows that the satisfying truth assignments suddenly shift from being relatively different from each other to being very similar to each other.##属性不符

  5. The WFCAM Transit Survey

    Directory of Open Access Journals (Sweden)

    Hodgkin S.

    2011-02-01

    Full Text Available The WFCAM Transit Survey (WTS has been obtaining data on the United Kingdom Infrared Telescope since 2007. The WTS targets about 8,000 M dwarfs over several square degrees of sky, and aims to find low-mass eclipsing binaries and planets, down to the size of the Earth, transiting M dwarf stars with periods up to a few days.

  6. Stateless Transitive Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    MA Chun-guang; CAI Man-chun; YANG Yi-xian

    2004-01-01

    A new practical method is introduced to transform the stateful transitive signature scheme to stateless one without the loss of security. According to the approach, two concrete stateless transitive signature schemes based on Factoring and RSA are presented respectively. Under the assumption of the hardness of factoring and one-more- RSA-inversion problem, both two schemes are secure under the adaptive chosen-message attacks in random oracle model.

  7. Matter in transition

    CERN Document Server

    Anderson, Lara B; Raghuram, Nikhil; Taylor, Washington

    2015-01-01

    We explore a novel type of transition in certain 6D and 4D quantum field theories, in which the matter content of the theory changes while the gauge group and other parts of the spectrum remain invariant. Such transitions can occur, for example, for SU(6) and SU(7) gauge groups, where matter fields in a three-index antisymmetric representation and the fundamental representation are exchanged in the transition for matter in the two-index antisymmetric representation. These matter transitions are realized by passing through superconformal theories at the transition point. We explore these transitions in dual F-theory and heterotic descriptions, where a number of novel features arise. For example, in the heterotic description the relevant 6D SU(7) theories are described by bundles on K3 surfaces where the geometry of the K3 is constrained in addition to the bundle structure. On the F-theory side, non-standard representations such as the three-index antisymmetric representation of SU(N) require Weierstrass models...

  8. STUDY ON TOUGHENING OF PA6/POE-g-MAH/NANO BaSO, BLENDS%PA6/POE-g-MAH/纳米BaSO4三元复合体系增韧研究

    Institute of Scientific and Technical Information of China (English)

    王三昭; 丁筠; 郭婷; 林光强; 冯炎聪; 程晓静; 乔辉; 吴立峰

    2011-01-01

    POE-g-MAH and nano BaSO4 were used to toughen PA6, and the brittle- ductile transition of PA6/POE-g-MAH blends was studied. The toughness effects of different contents of nano BaSO4 on the PA6/POE-g-MAH blends was also discussed. Results showed that brittle-ductile transformation produced when the content of POE-g-MAH was between 10% -20%, the notched impact strength of composites increased greatly, while the tensile strength remained.%采用纳米BaSO4及马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)对聚酰胺(PA)6进行增韧改性,研究了PA6/POE-g-MAH共混体系的脆韧转变,讨论了纳米BaSO4的用量对PA6/POE-g-MAH脆韧转变体系的增韧作用.结果显示,当POE-g-MAH质量分数为10%~20%时,PA6/POE-g-MAH共混体系发生脆韧转变,纳米BaSO4对PA6POE-g-MAH(85/15)脆韧转变体系的增韧效果明显,并且对材料的拉伸性能影响不大.

  9. Examining hydrogen transitions.

    Energy Technology Data Exchange (ETDEWEB)

    Plotkin, S. E.; Energy Systems

    2007-03-01

    This report describes the results of an effort to identify key analytic issues associated with modeling a transition to hydrogen as a fuel for light duty vehicles, and using insights gained from this effort to suggest ways to improve ongoing modeling efforts. The study reported on here examined multiple hydrogen scenarios reported in the literature, identified modeling issues associated with those scenario analyses, and examined three DOE-sponsored hydrogen transition models in the context of those modeling issues. The three hydrogen transition models are HyTrans (contractor: Oak Ridge National Laboratory), MARKAL/DOE* (Brookhaven National Laboratory), and NEMS-H2 (OnLocation, Inc). The goals of these models are (1) to help DOE improve its R&D effort by identifying key technology and other roadblocks to a transition and testing its technical program goals to determine whether they are likely to lead to the market success of hydrogen technologies, (2) to evaluate alternative policies to promote a transition, and (3) to estimate the costs and benefits of alternative pathways to hydrogen development.

  10. Parametric modal transition systems

    DEFF Research Database (Denmark)

    Beneš, Nikola; Křetínský, Jan; Larsen, Kim Guldstrand;

    2011-01-01

    Modal transition systems (MTS) is a well-studied specification formalism of reactive systems supporting a step-wise refinement methodology. Despite its many advantages, the formalism as well as its currently known extensions are incapable of expressing some practically needed aspects in the refin......Modal transition systems (MTS) is a well-studied specification formalism of reactive systems supporting a step-wise refinement methodology. Despite its many advantages, the formalism as well as its currently known extensions are incapable of expressing some practically needed aspects...... in the refinement process like exclusive, conditional and persistent choices. We introduce a new model called parametric modal transition systems (PMTS) together with a general modal refinement notion that overcome many of the limitations and we investigate the computational complexity of modal refinement checking....

  11. Citizens in sustainable transitions

    DEFF Research Database (Denmark)

    Hoffmann, Birgitte; Agger, Annika

    2013-01-01

    The paper explores how local public authorities can support and facilitate citizens’ participa-tion and learning in sustainable transition in urban neighbourhoods, by supporting local in-termediaries. The role of intermediaries can be performed by a variety of actors such as public housing...... associations; NGO´s, or semi public institutions. Our claim is that intermediary actors have the potential to facilitate new platforms for citizens’ participation in urban sustainable transition due to their particular role in between public authorities and civil society. The key question of the paper is how...... the intermediary actors facilitate citizens' participatory processes in sustainable urban transitions, and the paper explores the concept of institutional capacity building as a way to develop learning processes and new practises? The aim is to analyse approaches of creating platforms for involving citizens...

  12. China's urban transition.

    Science.gov (United States)

    Pannell, C

    1995-01-01

    This article describes recent changes in urban patterns in Shanghai-Nanjing, Beijing-Tianjin-Tangshan, Canton-Hong Kong, and Dalian-Shenyang. The urban patterns in these metropolitan areas are viewed as part of an urban transition that is responding to population growth, a structural shift in employment, relaxed rules on migration and household registration, and foreign investment and trade. It is argued that these metropolitan coastal areas will form the key growth centers and will lead China's economic development. Urban transition is defined as the shift from rural to urban and from agricultural employment to industrial, commercial, or service employment. China's large cities always dominated as important centers of politics and trade. The recent shift is from interior to coastal cities due to a new world view and a movement away from the isolationism of prior centuries. It is assumed that cities are formed to take advantage of economies of scale in production, consumption, and distribution and to conform to regional specialization. Governments can intervene in growth processes. China's development of cities reflects state controls and market forces. The size and scale of China's population influenced the development process, which resulted in differences in the shape and process of the urban transition. It was under Chinese communism that cities became more than a set of discrete regional urban systems. Reference is made to Oshima's model of change that is specific to monsoon countries. Oshima argues that monsoon agricultural conditions require a distinct strategy based on full employment in order to achieve industrial transition. Rice cultivation requires a large and disciplined labor force. The discussion focuses on other models as well, such as the McGee's model of the extended metropolis and its extension by Zhou Yixing to China. China's changes may not follow Skeldon's models of urbanization in developing countries, because of state control of migration

  13. Electronic phase transitions

    CERN Document Server

    Kopaev, YuV

    1992-01-01

    Electronic Phase Transitions deals with topics, which are presently at the forefront of scientific research in modern solid-state theory. Anderson localization, which has fundamental implications in many areas of solid-state physics as well as spin glasses, with its influence on quite different research activities such as neural networks, are two examples that are reviewed in this book. The ab initio statistical mechanics of structural phase transitions is another prime example, where the interplay and connection of two unrelated disciplines of solid-state theory - first principle ele

  14. Spin transition in [Fe

    Science.gov (United States)

    Garcia, Y.; Ksenofontov, V.; Campbell, S. J.; Lord, J. S.; Boland, Y.; Gütlich, P.

    2004-12-01

    The reversible thermal spin transition which occurs in [Fe(phen)2(NCS)2] around T1/2 177 K has been investigated by muon spin relaxation (μSR) (10-280 K). The depolarisation curves are well described by two Lorentzian lines represent fast and slow components in the decay curves, with the initial asymmetry parameter of the fast component found to track the spin transition in [Fe(phen)2(NCS)2]. Comparison of zero-field and transverse field (20 Oe) μSR measurements shows that diamagnetic muonic species occur over the entire temperature range.

  15. Lost in Transit

    DEFF Research Database (Denmark)

    Lange, Ida Sofie Gøtzsche; Laursen, Lea Louise Holst; Lassen, Claus

    Thinking of Transit Places, the first sites that comes to mind will probably be airports, train stations and motorways. Such places are overall mono-functional with the embedded rationales of people's desires to move (themselves or goods) from one place to another. Often different service functions...... how a town primarily characterized by ferry transit is being challenged on its capacity to be a 'place' of meaning and social importance to its inhabitants. The paper raises the key question: Can a place become too well connected and this in such a manner that its identity and key character becomes...

  16. Pinocchio: Geppetto's transitional object

    Directory of Open Access Journals (Sweden)

    Gabriele Zeloni

    2015-01-01

    Full Text Available The literature has been considered by Freud and others after him, a form of unaware exploration of mind that can leads to discoveries similar to psychoanalysis’s discoveries. From this perspective, the author puts forward the following hypothesis: Pinocchio is a puppet who comes to life and is therefore, from a child's perception, a transitional object according to Winnicott. Consequently Geppetto is nothing more than the involuntary representation of any child interacting with the transitional object. The author explains the results of the analysis of the text in support of the hypothesis and reflects on the impact of The adventure of Pinocchio on the reader.

  17. Transition to the Cloud

    DEFF Research Database (Denmark)

    Hedman, Jonas; Xiao, Xiao

    2016-01-01

    companies operate. In this paper, we present a case study of an ERP vendor for SMB (small and mediumsize business) in making a transition towards a cloud-based business model. Through the theoretical lens of ecosystem, we are able to analyze the evolution of the vendor and its business network as a whole......The rising of cloud computing has dramatically changed the way software companies provide and distribute their IT product and related services over the last decades. Today, most software is bought offthe-shelf and distributed over the Internet. This transition is greatly influencing how software...

  18. Families in Transition.

    Science.gov (United States)

    Britton, Patti O., Ed.; McGee, Michael, Ed.

    1987-01-01

    This issue of "Emphasis" deals with families in transition, providing some model programs for the new family and some historical perspectives on how families have developed over time. Articles include: (1) "Nostalgia on the Right" (Nancy Theriot); (2) "Heart to Heart" (Nancy Harrington-MacLennan); (3) "The Media Get the Message" (Janet Alyn); (4)…

  19. Administrative Theory in Transition.

    Science.gov (United States)

    Griffiths, Daniel E.

    This monograph analyzes transition in educational administrative theory. A brief introductory section describes the theoretical movement, the substance and repercussions of Thomas Greenfield's critique of educational administrative theory in 1974, and emerging qualitative approaches. Seven readings, all written by the volume's author, view…

  20. Photoinduced phase transitions

    CERN Document Server

    Nasu, K

    2004-01-01

    A new class of insulating solids was recently discovered. Whenirradiated by a few visible photons, these solids give rise to amacroscopic excited domain that has new structural and electronicorders quite different from the starting ground state. This occurrenceis called "photoinduced phase transition", and this multi-authoredbook reviews recent theoretical and experimental studies of this newphenomenon.

  1. eta ' transition form factors

    NARCIS (Netherlands)

    Amo Sanchez, del P.; Raven, H.G.; Snoek, H.; BaBar, Collaboration

    2011-01-01

    eta((')) transition form factors in the momentum-transfer range from 4 to 40 GeV(2). The analysis is based on 469 fb(-1) of integrated luminosity collected at PEP-II with the BABAR detector at e(+)e(-) center-of-mass energies near 10.6 GeV.

  2. A Transiting Jupiter Analog

    CERN Document Server

    Kipping, David M; Henze, Chris; Teachey, Alex; Isaacson, Howard T; Petigura, Erik A; Marcy, Geoffrey W; Buchhave, Lars A; Chen, Jingjing; Bryson, Steve T; Sandford, Emily

    2016-01-01

    Decadal-long radial velocity surveys have recently started to discover analogs to the most influential planet of our solar system, Jupiter. Detecting and characterizing these worlds is expected to shape our understanding of our uniqueness in the cosmos. Despite the great successes of recent transit surveys, Jupiter analogs represent a terra incognita, owing to the strong intrinsic bias of this method against long orbital periods. We here report on the first validated transiting Jupiter analog, Kepler-167e (KOI-490.02), discovered using Kepler archival photometry orbiting the K4-dwarf KIC-3239945. With a radius of $(0.91\\pm0.02)$ $R_{\\mathrm{Jup}}$, a low orbital eccentricity ($0.06_{-0.04}^{+0.10}$) and an equilibrium temperature of $(131\\pm3)$ K, Kepler-167e bears many of the basic hallmarks of Jupiter. Kepler-167e is accompanied by three Super-Earths on compact orbits, which we also validate, leaving a large cavity of transiting worlds around the habitable-zone. With two transits and continuous photometric ...

  3. Variational transition state theory

    Energy Technology Data Exchange (ETDEWEB)

    Truhlar, D.G. [Univ. of Minnesota, Minneapolis (United States)

    1993-12-01

    This research program involves the development of variational transition state theory (VTST) and semiclassical tunneling methods for the calculation of gas-phase reaction rates and selected applications. The applications are selected for their fundamental interest and/or their relevance to combustion.

  4. Learning for Life Transitions

    Science.gov (United States)

    Varmecky, Jane Hyde

    2012-01-01

    Many adults return to formal learning situations to pursue lifelong learning goals because their lives are in transition from dealing with real-life problems such as divorce and re-marriage. The purpose of this study was to describe what couples learned that contributed to the success of their subsequent marriages and how they learned it. The…

  5. Outplacement as Transition Counseling.

    Science.gov (United States)

    Mirabile, Richard J.

    1985-01-01

    Describes outplacement counseling as a process that enables management to deal with the problem of the employee who must be released or the staff that must be reduced. Discusses the process of outplacement counseling, the stages of transition counseling, and techniques to be implemented. (BH)

  6. Families in Transition .

    Science.gov (United States)

    Bundy, Michael L., Ed.; Gumaer, James, Ed.

    1984-01-01

    Focuses on disrupted families and the role of the school counselor in helping children adjust. Describes characteristics of healthy families, and discusses the transition to the blended family, effects of divorce groups on children's classroom behavior, counseling children in stepfamilies, single-parent families, and parenting strengths of single…

  7. Transition and Financial Collapse

    NARCIS (Netherlands)

    Uhlig, H.F.H.V.S.

    1995-01-01

    One of the many problems facing the countries in transition from socialism to capitalism after the initial phase of privatization and restructuring is the lack of proven entrepreneurial talent in addition to a low initial level of capital. New entrepreneurs might find it hard to finance their start-

  8. Topological Transitions in Metamaterials

    CERN Document Server

    Krishnamoorthy, Harish N S; Narimanov, Evgenii; Kretzschmar, Ilona; Menon, Vinod M

    2011-01-01

    The ideas of mathematical topology play an important role in many aspects of modern physics - from phase transitions to field theory to nonlinear dynamics (1, 2). An important example of this is the Lifshitz transition (3), where the transformation of the Fermi surface of a metal from a closed to an open geometry (due to e.g. external pressure) leads to a dramatic effect on the electron magneto-transport (4). Here, we present the optical equivalent of the Lifshitz transition in strongly anisotropic metamaterials. When one of the components of the dielectric permittivity tensor of such a composite changes sign, the corresponding iso-frequency surface transforms from an ellipsoid to a hyperboloid. Since the photonic density of states can be related to the volume enclosed by the iso-frequency surface (5), such a topological transition in a metamaterial leads to a dramatic change in the photonic density of states, with a resulting effect on every single physical parameter related to the metamaterial - from thermo...

  9. Conceptions of Topological Transitivity

    CERN Document Server

    Akin, Ethan

    2011-01-01

    There are several different common definitions of a property in topological dynamics called "topological transitivity," and it is part of the folklore of dynamical systems that under reasonable hypotheses, they are equivalent. Various equivalences are proved in different places, but the full story is difficult to find. This note provides a complete description of the relationships among the different properties.

  10. Nursing Role Transition Preceptorship

    Science.gov (United States)

    Batory, Susan M.

    2014-01-01

    The preceptorship clinical experience in a practical nursing (PN) program at a Midwestern community college is considered crucial to the PN students' transition from novice nurse to professional nurse. However, no research has been available to determine whether the preceptorship clinical accomplishes its purpose. A case study was conducted to…

  11. 75 FR 76921 - Tobacco Transition Payment Program; Tobacco Transition Assessments

    Science.gov (United States)

    2010-12-10

    ... Corporation 7 CFR Part 1463 RIN 0560-AH30 Tobacco Transition Payment Program; Tobacco Transition Assessments... Commodity Credit Corporation (CCC) is modifying the regulations for the Tobacco Transition Payment Program (TTPP) to clarify, consistent with current practice and as required by the Fair and Equitable...

  12. Map Projection Transitions

    Directory of Open Access Journals (Sweden)

    Nedjeljko Frančula

    2013-06-01

    Full Text Available Map Projection Transitions is a very successful web application about map projections. The web page (http://www.jasondavies.com/maps/transition pre­sents a world map with graticule and country borders in the oblique Aitoff projection, with the South Pole. The map is not static, but animated. The South Pole moves toward the bottom and Earth rotates around its poles. The animation lasts five seconds, after which the projection changes and movement continues for five seconds, after which the projection changes again. Names of projections appear in a separate window. There are a total of 56 projections. The South Pole eventually becomes invisible and the North Pole appears at the top. Various parts of Earth appear in the center of the map by rotating around the poles.

  13. ATLAS Transition Radiation Tracker

    CERN Multimedia

    2006-01-01

    The ATLAS transition radiation tracker is made of 300'000 straw tubes, up to 144cm long. Filled with a gas mixture and threaded with a wire, each straw is a complete mini-detector in its own right. An electric field is applied between the wire and the outside wall of the straw. As particles pass through, they collide with atoms in the gas, knocking out electrons. The avalanche of electrons is detected as an electrical signal on the wire in the centre. The tracker plays two important roles. Firstly, it makes more position measurements, giving more dots for the computers to join up to recreate the particle tracks. Also, together with the ATLAS calorimeters, it distinguishes between different types of particles depending on whether they emit radiation as they make the transition from the surrounding foil into the straws.

  14. Transition Radiation Detectors

    CERN Document Server

    Andronic, A

    2012-01-01

    We review the basic features of transition radiation and how they are used for the design of modern Transition Radiation Detectors (TRD). The discussion will include the various realizations of radiators as well as a discussion of the detection media and aspects of detector construction. With regard to particle identification we assess the different methods for efficient discrimination of different particles and outline the methods for the quantification of this property. Since a number of comprehensive reviews already exist, we predominantly focus on the detectors currently operated at the LHC. To a lesser extent we also cover some other TRDs, which are planned or are currently being operated in balloon or space-borne astro-particle physics experiments.

  15. Control of Radiationless Transitions

    Science.gov (United States)

    Gordon, Robert J.; Seideman, Tamar

    2016-07-01

    Radiationless transitions provide a mechanism for ultrafast conversion of electronic energy into nuclear motion of a molecule. This effect results from strong vibronic mixing at geometries where two or more electronic states are degenerate (or nearly degenerate in regions of avoiding crossing).We review in this chapter different approaches to controlling such transitions. General control strategies include (1) tuning the frequency of the actinic light to enhance the yield of a specific product, (2) tailoring the properties (spectral phase and amplitude) of the excitation source to guide the generated vibrational wave packet to a specific region of the conical seam between the potential energy surfaces, and (3) modifying the shape and location of the conical intersection either by altering the chemical environment of the molecule or by introducing a strong electromagnetic field. The goals of this chapter are to reveal underlying mechanistic similarities among these general methods and to outline areas for future research.

  16. Eccentricity from transit photometry

    DEFF Research Database (Denmark)

    Van Eylen, Vincent; Albrecht, Simon

    2015-01-01

    and can be described by a Rayleigh distribution with $\\sigma$ = 0.049 $\\pm$ 0.013. This is in full agreement with solar system eccentricities, but in contrast to the eccentricity distributions previously derived for exoplanets from radial velocity studies. Our findings are helpful in identifying which...... (TTVs), and we present some previously unreported TTVs. Finally transit durations help distinguish between false positives and true planets and we use our measurements to confirm six new exoplanets....

  17. Women in Transition

    OpenAIRE

    UNICEF Innocenti Research Centre. MONEE project

    1999-01-01

    The 1999 Central and Eastern Europe and Commonwealth of Independent States Regional Monitoring Report focuses on the experiences of girls and women during the transition, highlighting their role in regional progress and the obstacles they face. The Report covers a broad range of issues, including women’s participation in the emerging market economy and democratic governments, female access to health and education, trends in family formation and violence against women and girls. The Report cal...

  18. Monte Carlo transition probabilities

    OpenAIRE

    Lucy, L. B.

    2001-01-01

    Transition probabilities governing the interaction of energy packets and matter are derived that allow Monte Carlo NLTE transfer codes to be constructed without simplifying the treatment of line formation. These probabilities are such that the Monte Carlo calculation asymptotically recovers the local emissivity of a gas in statistical equilibrium. Numerical experiments with one-point statistical equilibrium problems for Fe II and Hydrogen confirm this asymptotic behaviour. In addition, the re...

  19. A Continent in Transition

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    AFRICA has survived a year of great change.Most notable has been the transition affecting North Africa,where waves of protests resulted in regime changes in Libya,Tunisia,and Egypt.When the dust had settled,Libya's former leader Muammar Gaddafi lay dead in a storm water drain and Egypt's former leader Hosni Mubarrak lay frail and fearful on a bed in a courtroom,on trial for his life.

  20. Transitional justice and aid

    OpenAIRE

    Hellsten, Sirkku K.

    2012-01-01

    This paper examines the current security-governance-development nexus, something that is often also discussed under the concept of transitional justice (TJ). The paper analyses how the ambiguous, evolving and expanding nature of the concept of TJ affects the planning, coordination, evaluation and assessment of aid given to conflict ridden, post-conflict or (post) authoritarian societies in order to strengthen their democracy. Special attention is paid to gender justice. Illustrations are draw...

  1. Stimulated coherent transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hung-chi Lihn

    1996-03-01

    Coherent radiation emitted from a relativistic electron bunch consists of wavelengths longer than or comparable to the bunch length. The intensity of this radiation out-numbers that of its incoherent counterpart, which extends to wavelengths shorter than the bunch length, by a factor equal to the number of electrons in the bunch. In typical accelerators, this factor is about 8 to 11 orders of magnitude. The spectrum of the coherent radiation is determined by the Fourier transform of the electron bunch distribution and, therefore, contains information of the bunch distribution. Coherent transition radiation emitted from subpicosecond electron bunches at the Stanford SUNSHINE facility is observed in the far-infrared regime through a room-temperature pyroelectric bolometer and characterized through the electron bunch-length study. To measure the bunch length, a new frequency-resolved subpicosecond bunch-length measuring system is developed. This system uses a far-infrared Michelson interferometer to measure the spectrum of coherent transition radiation through optical autocorrelation with resolution far better than existing time-resolved methods. Hence, the radiation spectrum and the bunch length are deduced from the autocorrelation measurement. To study the stimulation of coherent transition radiation, a special cavity named BRAICER is invented. Far-infrared light pulses of coherent transition radiation emitted from electron bunches are delayed and circulated in the cavity to coincide with subsequent incoming electron bunches. This coincidence of light pulses with electron bunches enables the light to do work on electrons, and thus stimulates more radiated energy. The possibilities of extending the bunch-length measuring system to measure the three-dimensional bunch distribution and making the BRAICER cavity a broadband, high-intensity, coherent, far-infrared light source are also discussed.

  2. ATLAS Transitional Radiation Tracker

    CERN Multimedia

    ATLAS Outreach

    2006-01-01

    This colorful 3D animation is an excerpt from the film "ATLAS-Episode II, The Particles Strike Back." Shot with a bug's eye view of the inside of the detector. The viewer is taken on a tour of the inner workings of the transitional radiation tracker within the ATLAS detector. Subjects covered include what the tracker is used to measure, its structure, what happens when particles pass through the tracker, how it distinguishes between different types of particles within it.

  3. Nav Status & Daily Transit Report -

    Data.gov (United States)

    Department of Transportation — Displays a breakdown of vessel transit through Eisenhower lock in Massena, NY by different types of vessels and comparing current year transits to the year previous....

  4. Precision photometry for planetary transits

    CERN Document Server

    Pont, F; Pont, Frederic; Moutou, Claire

    2007-01-01

    We review the state of the art in follow-up photometry for planetary transit searches. Three topics are discussed: (1) Photometric monitoring of planets discovered by radial velocity to detect possible transits (2) Follow-up photometry of candidates from photometric transit searches to weed out eclipsing binaries and false positives (3) High-precision lightcurves of known transiting planets to increase the accuracy on the planet parameters.

  5. Kinematics of the Torcal Shear Zone: Transpressional tectonics in a salient-recess transition at the northern Gibraltar Arc

    Science.gov (United States)

    Barcos, L.; Balanyá, J. C.; Díaz-Azpiroz, M.; Expósito, I.; Jiménez-Bonilla, A.

    2015-11-01

    Complex strain patterns in the Gibraltar Arc derive from the interaction between the westward drift - and concomitant back-arc extension - of the arc hinterland (Alboran Domain) and the Europe-Africa convergence. In order to explore strain partitioning modes within the arc and the role played by large-scale oblique structures, we have studied the kinematics of the Torcal Shear Zone located at the northern branch of the Gibraltar Arc. The Torcal Shear Zone is a 70 km-long, E-W brittle-ductile shear zone that underwent overall dextral transpression during the Late Miocene to Quaternary time. Within the Torcal Shear Zone strain is highly partitioned at multiple scales into shortening, oblique, extensional and strike-slip structures. Moreover, strain partitioning is heterogeneous along-strike giving rise to four distinct structural domains. In the central sector the strain is pure-shear dominated, although narrow sectors parallel to the shear walls are simple-shear dominated. A single N99°E-N109°E trending horizontal velocity vector (V→) could explain the kinematics of the entire central sector of the Torcal Shear Zone. Lateral domains have different strain patterns and are comparable to splay-dominated and thrust-dominated strike-slip fault tips. The Torcal Shear Zone provokes the subvertical extrusion of the External Betics units against the Alboran Domain and a dextral deflection of the structural trend. Moreover, the estimated V→ points to the importance of the westward motion of the hinterland relative to the external wedge and fits well with the radial outward thrusting pattern identified in the arc.

  6. Searching for transit timing variations in transiting exoplanet systems

    CERN Document Server

    Hrudková, Marie; Benn, Chris; Pollacco, Don; Gibson, Neale; Joshi, Yogesh; Harmanec, Petr; Tulloch, Simon

    2008-01-01

    Searching for transit timing variations in the known transiting exoplanet systems can reveal the presence of other bodies in the system. Here we report such searches for two transiting exoplanet systems, TrES-1 and WASP-2. Their new transits were observed with the 4.2m William Herschel Telescope located on La Palma, Spain. In a continuing programme, three consecutive transits were observed for TrES-1, and one for WASP-2 during September 2007. We used the Markov Chain Monte Carlo simulations to derive transit times and their uncertainties. The resulting transit times are consistent with the most recent ephemerides and no conclusive proof of additional bodies in either system was found.

  7. Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Preliminary Evaluation Results

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, K.; Eudy, L.

    2007-03-01

    This report provides an evaluation of three prototype fuel cell-powered transit buses operating at AC Transit in Oakland, California, and six baseline diesel buses similar in design to the fuel cell buses.

  8. Mexico in Transition

    Directory of Open Access Journals (Sweden)

    Barbara Hogenboom

    2003-10-01

    Full Text Available – Mexico’s Politics and Society in Transition, edited by Joseph S. Tulchin and Andrew D. Selee. Boulder/London: Lynne Rienner Publishers, 2003. – México al inicio del siglo XXI: democracia, cuidadanía y desarrollo, edited by Alberto Aziz Nassif. México: CIESAS & Miguel Ángel Porrúa, 2003. – Globalización y alternativas incluyentes para el siglo XXI, edited by Jorge Basave, Alejandro Dabat, Carlos Morera, Miguel Ángel Rivera Ríos & Francisco Rodríguez. México: Instituto de Investigaciones Económica. UNAM & Miguel Ángel Porrúa, 2002.

  9. Wetting Transition in Water

    Science.gov (United States)

    Friedman, S. R.; Khalil, M.; Taborek, P.

    2013-11-01

    Optical images were used to study the wetting behavior of water on graphite, sapphire, and quartz along the liquid vapor coexistence curve from room temperature to 300°C. Wetting transitions were identified by the temperature at which the contact angle decreased to zero and also by the disappearance of dropwise condensation. These two methods yielded consistent values for the wetting temperatures, which were 185°C, 234°C, and 271°C for water on quartz, sapphire, and graphite, respectively. We compare our results with the theoretical predictions based on a simplified model of the water-substrate potential and sharp interfaces.

  10. Transition Path Theory

    Science.gov (United States)

    vanden-Eijnden, E.

    The dynamical behavior of many systems arising in physics, chemistry, biology, etc. is dominated by rare but important transition events between long lived states. For over 70 years, transition state theory (TST) has provided the main theoretical framework for the description of these events [17,33,34]. Yet, while TST and evolutions thereof based on the reactive flux formalism [1, 5] (see also [30,31]) give an accurate estimate of the transition rate of a reaction, at least in principle, the theory tells very little in terms of the mechanism of this reaction. Recent advances, such as transition path sampling (TPS) of Bolhuis, Chandler, Dellago, and Geissler [3, 7] or the action method of Elber [15, 16], may seem to go beyond TST in that respect: these techniques allow indeed to sample the ensemble of reactive trajectories, i.e. the trajectories by which the reaction occurs. And yet, the reactive trajectories may again be rather uninformative about the mechanism of the reaction. This may sound paradoxical at first: what more than actual reactive trajectories could one need to understand a reaction? The problem, however, is that the reactive trajectories by themselves give only a very indirect information about the statistical properties of these trajectories. This is similar to why statistical mechanics is not simply a footnote in books about classical mechanics. What is the probability density that a trajectory be at a given location in state-space conditional on it being reactive? What is the probability current of these reactive trajectories? What is their rate of appearance? These are the questions of interest and they are not easy to answer directly from the ensemble of reactive trajectories. The right framework to tackle these questions also goes beyond standard equilibrium statistical mechanics because of the nontrivial bias that the very definition of the reactive trajectories imply - they must be involved in a reaction. The aim of this chapter is to

  11. ALICE Transition Radiation Detector

    CERN Multimedia

    Pachmayer, Y

    2013-01-01

    The Transition Radiation Detector (TRD) is the main electron detector in ALICE. In conduction with the TPC and the ITS, it provides the necessary electron identification capability to study: - Production of light and heavy vector mesons as well as the continuum in the di-electron channel, - Semi leptonic decays of hadrons with open charm and open beauty via the single-electron channel using the displaced vertex information provided by the ITS, - Correlated DD and BB pairs via coincidences of electrons in the central barrel and muons in the forward muon arm, - Jets with high Pτ tracks in one single TRD stack.

  12. The backyard of transition

    Directory of Open Access Journals (Sweden)

    Đurić Jelena B.

    2004-01-01

    Full Text Available The reflection on the current period of transition in Serbian society indicates deep contradictions between the urge for European integration and the delay of institutional transformation that fuse with the indolence of a large part of the people. The crisis of values is conspicuous almost everywhere. Continuous changes have had hard consequences on Serbian society. During these changes moral patterns, values, spirituality were destroyed, rebuilt, and lost again. Hence, Serbian society now lies on the ruins of past 'traditions', general values, collective identities, and a common purpose. In everyday life, it is noticeable very often as, for example, in the Belgrade 'park-scape' whose photos obviously illustrate these problems.

  13. Understanding quantum phase transitions

    CERN Document Server

    Carr, Lincoln

    2010-01-01

    Quantum phase transitions (QPTs) offer wonderful examples of the radical macroscopic effects inherent in quantum physics: phase changes between different forms of matter driven by quantum rather than thermal fluctuations, typically at very low temperatures. QPTs provide new insight into outstanding problems such as high-temperature superconductivity and display fundamental aspects of quantum theory, such as strong correlations and entanglement. Over the last two decades, our understanding of QPTs has increased tremendously due to a plethora of experimental examples, powerful new numerical meth

  14. Physicians in transition.

    Science.gov (United States)

    Bluestein, P

    1995-12-01

    The study of physicians as managed care executives has been relatively recent. Much of what was written in the past focused primarily on doctors who had taken hospital-based administrative positions, especially as medical directors or vice presidents of medical affairs.1 But the '80s brought rising health care costs and the emergence of the "O's"--HMOs, PPOs, UROs, EPOs, PHOs, H2Os, and Uh-Ohs--in response. It also brought a growing number of physicians who traded their white coats and their particular "ologies" for the blue suits of executive management. I am convinced that it is important now, and will be increasingly important in the future, to better understand that transition. That belief led me to undertake, with the help and support of ACPE, the survey that is reported in this article. A questionnaire was sent in 1994 to a random sample of 300 managed care physician executive members of ACPE. Responses were returned by 225 members, a response rate of better than 80 percent. Twenty-five of the responses were not applicable, having been returned by physicians who had never made a transition from clinical careers. The remaining 230 responses form the basis for this report.

  15. Electroweak phase transitions

    CERN Document Server

    Fodor, Z

    2000-01-01

    Recent developments on the four dimensional (4d) lattice studies of the finite temperature electroweak phase transition (EWPT) are summarized. The phase diagram is given in the continuum limit. The finite temperature SU(2)-Higgs phase transition is of first order for Higgs-boson masses m/sub H/<66.5+or-1.4 GeV. Above this endpoint only a rapid cross-over can be seen. The full 4d result agrees completely with that of the dimensional reduction approximation. The Higgs-boson endpoint mass in the standard model (SM) would be 72.1+or-1. 4 GeV. Taking into account the LEP Higgs-boson mass lower bound excludes any EWPT in the SM. A one-loop calculation of the static potential in the SU(2)-Higgs model enables a precise comparison between lattice simulations and perturbative results. The most popular extension of the SM, the minimal supersymmetric SM (MSSM) is also studied on 4d lattices. (17 refs).

  16. Structural transition metal chemistry

    CERN Document Server

    Anderson, K M

    2002-01-01

    This thesis is divided up into five chapters as outlined below. Chapter 1 gives the background to the techniques used in this thesis including X-ray structure determination and ab initio methods. An overview of some recent studies using ab initio methods to study transition metal complexes is also given. Chapter 2 investigates structural trans influence in a number of transition metal and p-block complexes. The database and ab initio studies showed that the classical trans influence model based on Pt(II) chemistry does not always hold. For some systems (eg. d sup 1 sup 0 s sup 0 for Sb sup V and Sn sup I sup V) the cis influence is of similar magnitude to the trans influence. For other systems (d sup 0), the trans influence is not as powerful as usually assumed. Chapter 3 is an investigation into the bridging chloride unit. A database study was performed on three systems (M-CI-M', M-CI...H and M-CI...Li/Na/K). Reaction pathway analysis was carried out for the M-CI-M' case and showed that bond order is not con...

  17. Tiber Personal Rapid Transit

    Directory of Open Access Journals (Sweden)

    Diego Carlo D'agostino

    2011-02-01

    Full Text Available The project “Tiber Personal Rapid Transit” have been presented by the author at the Rome City Vision Competition1 2010, an ideas competition, which challenges architects, engineers, designers, students and creatives individuals to develop visionary urban proposals with the intention of stimulating and supporting the contemporary city, in this case Rome. The Tiber PRT proposal tries to answer the competition questions with the definition of a provocative idea: a Personal Rapid transit System on the Tiber river banks. The project is located in the central section of the Tiber river and aims at the renewal of the river banks with the insertion of a Personal Rapid Transit infrastructure. The project area include the riverbank of Tiber from Rome Transtevere RFI station to Piazza del Popolo, an area where main touristic and leisure attractions are located. The intervention area is actually no used by the city users and residents and constitute itself a strong barrier in the heart of the historic city.

  18. 76 FR 77302 - Federal Transit Administration

    Science.gov (United States)

    2011-12-12

    ... Federal Transit Administration FY 2011 Discretionary Sustainability Funding Opportunity; Transit... Discretionary Bus and Bus Facilities Program AGENCY: Federal Transit Administration (FTA), DOT. ACTION: FTA...'s (DOT) Federal Transit Administration (FTA) announces the selection of Fiscal Year (FY)...

  19. Frictional Behavior of Anorthite and Quartz at High Pressure and High Temperature Conditions

    Science.gov (United States)

    Arai, T.; Masuda, K.; Fujimoto, K.; Shigematsu, N.; Ohtani, T.; Sumii, T.; Okuyama, Y.

    2002-12-01

    Most of earthquakes in the crust occurred at the depth of 5 to 20km, and the distribution of mainshocks matches the base of this zone, where is considered to be consistent with brittle-ductile transition zone. The lower boundary on seismicity results from a switch from velocity weakening to velocity strengthening of friction with increasing temperature. The physical properties of rocks associated with elevated temperatures were determined by many frictional experiments. In these experimental studies, quartz, which controls the rock strength at brittle-ductile transition zone, was generally used. On the other hand, frictional experiment with feldspar is very few in spite of dominant phase in the crust, because feldspar behaves in a brittle manner at greenshist facies. However, recent studies indicate fine-grained plagioclase (1um) contributed deformation process largely at the Hatagawa fault zone, northeast Japan, where is considered to have been brittle-ductile transition zone in the past. In order to understand the source processes of earthquakes, it is important to evaluate the physical properties of fine grained plagioclace as well as those of quartz. In this study, we conducted frictional experiments by using anorthite and quartz gouges under high pressure and high temperature in a triaxial apparatus, and compared frictional behaviors of two minerals with elevated temperature. Temperature varied from room temperature to 800°C. Fine- (1-10um,1um) and coarse-grained (50um, 100um) samples were prepared to evaluate the effect of different grain size as observed Hatagawa fault zone. The samples were put between upper and lower sawcut cylinders (20mm diameter x 40mm long). The sawcut was oriented at 30° to the loading axis. These were jacketed with thin sleeves of annealed Cu. Pore fluids accelerated deformation process of Hatagawa mylonite at higher temperature than 600°C under the same effective confining pressure (Masuda et al., presented in this meeting

  20. Improved mechanical properties of thermoelectric (Bi0.2Sb0.8)2Te3 by nanostructuring

    Science.gov (United States)

    Lavrentev, M. G.; Osvenskii, V. B.; Parkhomenko, Yu. N.; Pivovarov, G. I.; Sorokin, A. I.; Bulat, L. P.; Kim, H.-S.; Witting, I. T.; Snyder, G. J.; Bublik, V. T.; Tabachkova, N. Yu.

    2016-10-01

    Temperature-dependent strength of Bi-Sb-Te under uniaxial compression is investigated. Bi-Sb-Te samples were produced by three methods: vertical zone-melting, hot extrusion, and spark plasma sintering (SPS). For zone-melted and extruded samples, the brittle-ductile transition occurs over a temperature range of 200-350 °C. In nanostructured samples produced via SPS, the transition is observed in a narrower temperature range of 170-200 °C. At room temperature, the strength of the nanostructured samples is higher than that of zone-melted and extruded samples, but above 300 °C, all samples decrease to roughly the same strength.

  1. Effects of Ni vacancy, Ni antisite, Cr and Pt on the third-order elastic constants and mechanical properties of NiAl

    KAUST Repository

    Wu, Shaohua

    2014-12-01

    Effects of Ni vacancy, Ni antisite in Al sublattice, Cr in Al sublattice, Pt in Ni sublattice on the second-order elastic constants (SOECs) and third-order elastic constants (TOECs) of the B2 NiAl have been investigated using the first-principles methods. Lattice constant and the SOECs of NiAl are in good agreement with the previous results. The brittle/ductile transition map based on Pugh ratio G/B and Cauchy pressure Pc shows that Ni antisite, Cr, Pt and pressure can improve the ductility of NiAl, respectively. Ni vacancy and lower pressure can enhance the Vickers hardness Hv of NiAl. The density of states (DOS) and the charge density difference are also used to analysis the effects of vacancy, Ni antisite, Cr and Pt on the mechanical properties of NiAl, and the results are in consistent with the transition map. © 2014 Elsevier Ltd. All rights reserved.

  2. Invariant probabilities of transition functions

    CERN Document Server

    Zaharopol, Radu

    2014-01-01

    The structure of the set of all the invariant probabilities and the structure of various types of individual invariant probabilities of a transition function are two topics of significant interest in the theory of transition functions, and are studied in this book. The results obtained are useful in ergodic theory and the theory of dynamical systems, which, in turn, can be applied in various other areas (like number theory). They are illustrated using transition functions defined by flows, semiflows, and one-parameter convolution semigroups of probability measures. In this book, all results on transition probabilities that have been published by the author between 2004 and 2008 are extended to transition functions. The proofs of the results obtained are new. For transition functions that satisfy very general conditions the book describes an ergodic decomposition that provides relevant information on the structure of the corresponding set of invariant probabilities. Ergodic decomposition means a splitting of t...

  3. Learning phase transitions by confusion

    CERN Document Server

    van Nieuwenburg, Evert P L; Huber, Sebastian D

    2016-01-01

    Classifying phases of matter is a central problem in physics. For quantum mechanical systems, this task can be daunting owing to the exponentially large Hilbert space. Thanks to the available computing power and access to ever larger data sets, classification problems are now routinely solved using machine learning techniques. Here, we propose to use a neural network based approach to find phase transitions depending on the performance of the neural network after training it with deliberately incorrectly labelled data. We demonstrate the success of this method on the topological phase transition in the Kitaev chain, the thermal phase transition in the classical Ising model, and the many-body-localization transition in a disordered quantum spin chain. Our method does not depend on order parameters, knowledge of the topological content of the phases, or any other specifics of the transition at hand. It therefore paves the way to a generic tool to identify unexplored phase transitions.

  4. Strategic planning in transition

    DEFF Research Database (Denmark)

    Olesen, Kristian; Richardson, Tim

    2012-01-01

    In this paper, we analyse how contested transitions in planning rationalities and spatial logics have shaped the processes and outputs of recent episodes of Danish ‘strategic spatial planning’. The practice of ‘strategic spatial planning’ in Denmark has undergone a concerted reorientation...... in the recent years as a consequence of an emerging neoliberal agenda promoting a growth-oriented planning approach emphasising a new spatial logic of growth centres in the major cities and urban regions. The analysis, of the three planning episodes, at different subnational scales, highlights how this new...... style of ‘strategic spatial planning’ with its associated spatial logics is continuously challenged by a persistent regulatory, top-down rationality of ‘strategic spatial planning’, rooted in spatial Keynesianism, which has long characterised the Danish approach. The findings reveal the emergence...

  5. Transitive conformal holonomy groups

    CERN Document Server

    Alt, Jesse

    2011-01-01

    For $(M,[g])$ a conformal manifold of signature $(p,q)$ and dimension at least three, the conformal holonomy group $\\mathrm{Hol}(M,[g]) \\subset O(p+1,q+1)$ is an invariant induced by the canonical Cartan geometry of $(M,[g])$. We give a description of all possible connected conformal holonomy groups which act transitively on the M\\"obius sphere $S^{p,q}$, the homogeneous model space for conformal structures of signature $(p,q)$. The main part of this description is a list of all such groups which also act irreducibly on $\\R^{p+1,q+1}$. For the rest, we show that they must be compact and act decomposably on $\\R^{p+1,q+1}$, in particular, by known facts about conformal holonomy the conformal class $[g]$ must contain a metric which is locally isometric to a so-called special Einstein product.

  6. Transit spectroscopy with GTC

    Directory of Open Access Journals (Sweden)

    Osorio M.R. Zapatero

    2013-04-01

    Full Text Available Thanks to different ground-based surveys and space missions, nowadays we have a fairly large sample of discovered extra-solar planets to study and, without a doubt, this number will increase in the future. One of the most succesful techniques that allows us to prove the physical properties and atmospheric composition of these exoplanets is transmission spectroscopy. The level of precision that is require to measure these effects provides a technical challenge that is solved by using big telescopes and stable instruments to reach low noise levels. In this article, we will discuss the use of the 10m class telescope GTC to observed planetary transits in spectroscopic mode and some of the results that we are currently obtaining.

  7. Phases and Phase Transitions

    Science.gov (United States)

    Gitterman, Moshe

    2014-09-01

    In discussing phase transitions, the first thing that we have to do is to define a phase. This is a concept from thermodynamics and statistical mechanics, where a phase is defined as a homogeneous system. As a simple example, let us consider instant coffee. This consists of coffee powder dissolved in water, and after stirring it we have a homogeneous mixture, i.e., a single phase. If we add to a cup of coffee a spoonful of sugar and stir it well, we still have a single phase -- sweet coffee. However, if we add ten spoonfuls of sugar, then the contents of the cup will no longer be homogeneous, but rather a mixture of two homogeneous systems or phases, sweet liquid coffee on top and coffee-flavored wet sugar at the bottom...

  8. Nonadiabatic transition path sampling

    Science.gov (United States)

    Sherman, M. C.; Corcelli, S. A.

    2016-07-01

    Fewest-switches surface hopping (FSSH) is combined with transition path sampling (TPS) to produce a new method called nonadiabatic path sampling (NAPS). The NAPS method is validated on a model electron transfer system coupled to a Langevin bath. Numerically exact rate constants are computed using the reactive flux (RF) method over a broad range of solvent frictions that span from the energy diffusion (low friction) regime to the spatial diffusion (high friction) regime. The NAPS method is shown to quantitatively reproduce the RF benchmark rate constants over the full range of solvent friction. Integrating FSSH within the TPS framework expands the applicability of both approaches and creates a new method that will be helpful in determining detailed mechanisms for nonadiabatic reactions in the condensed-phase.

  9. The Geometric Transition Revisited

    CERN Document Server

    Gwyn, Rhiannon

    2007-01-01

    Our intention in this article is to review known facts and to summarise recent advances in the understanding of geometric transitions and the underlying open/closed duality in string theory. We aim to present a pedagogical discussion of the gauge theory underlying the Klebanov--Strassler model and review the Gopakumar--Vafa conjecture based on topological string theory. These models are also compared in the T-dual brane constructions. We then summarise a series of papers verifying both models on the supergravity level. An appendix provides extensive background material about conifold geometries. We pay special attention to their complex structures and re-evaluate the supersymmetry conditions on the background flux in constructions with fractional D3-branes on the singular (Klebanov--Strassler) and resolved (Pando Zayas--Tseytlin) conifolds. We agree with earlier results that only the singular solution allows a supersymmetric flux, but point out the importance of using the correct complex structure to reach th...

  10. Transitions in Secondary Education

    DEFF Research Database (Denmark)

    Larsen, Britt Østergaard; Jensen, Leif; Pilegaard Jensen, Torben

    2014-01-01

    The purpose of this article is to investigate educational choices and attainment of children who experience social problems during their upbringing. The study explores the extent to which social problems can help explain the gaps in entry and dropout rates in upper secondary education in Denmark...... between students from different socioeconomic backgrounds. Population-based registers are used to include information on family upbringing, e.g. alcohol abuse, criminality, use of psychopharmaca and out-of-home placement. We estimate a parsimonious version of Cameron and Heckman's (2001) dynamic...... statistical model of educational progression. By using this method, we parcel educational attainment into a series of transitions and the model is able to control for educational selection and unobserved heterogeneity. We apply counterfactual analyses to allow a formal decomposition of the effects of social...

  11. Electroweak phase transition in technicolor

    CERN Document Server

    Jarvinen, Matti

    2010-01-01

    Several phenomenologically viable walking technicolor models have been proposed recently. I demonstrate that these models can have first order electroweak phase transitions, which are sufficiently strong for electroweak baryogenesis. Strong dynamics can also lead to several separate transitions at the electroweak scale, with the possibility of a temporary restoration and an extra breaking of the electroweak symmetry. First order phase transitions will produce gravitational waves, which may be detectable at future experiments.

  12. Transition Complexity of Incomplete DFAs

    Directory of Open Access Journals (Sweden)

    Yuan Gao

    2010-08-01

    Full Text Available In this paper, we consider the transition complexity of regular languages based on the incomplete deterministic finite automata. A number of results on Boolean operations have been obtained. It is shown that the transition complexity results for union and complementation are very different from the state complexity results for the same operations. However, for intersection, the transition complexity result is similar to that of state complexity.

  13. Aspects of Transition in Turbomachines

    Science.gov (United States)

    Hodson, H. P.

    2007-01-01

    This talk provides a description of several types of transition encountered in turbomachines. It is based largely on personal experience of the detection of transition in turbomachines. Examples are taken from axial compressors, axial turbines and radial turbines. The illustrations are concerned with transition in steady and unsteady boundary layers that develop under the influence of two-dimensional and three-dimensional flow fields.

  14. Transition in hypersonic boundary layers

    Directory of Open Access Journals (Sweden)

    Chuanhong Zhang

    2015-10-01

    Full Text Available Transition and turbulence production in a hypersonic boundary layer is investigated in a Mach 6 wind tunnel using Rayleigh-scattering visualization, fast-response pressure measurements, and particle image velocimetry. It is found that the second-mode instability is a key modulator of the transition process. Although the second-mode is primarily an acoustic wave, it causes the formation of high-frequency vortical waves, which triggers a fast transition to turbulence.

  15. Probabilistic excitation of plasma transitions

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Sanae; Toda, Shinichiro; Yagi, Masatoshi [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics; Itoh, Kimitaka; Fukuyama, Atsushi

    1998-12-01

    Statistical property of an excitation of plasma transition is analyzed, which takes place in a strongly turbulent state. Transition characteristics which have been studied in a deterministic picture are re-examined. Model equations of transition, with a hysteresis nature in flux-gradient relation in the presence of strong self-noise, are solved and the dynamics of plasma gradient and turbulent-driven flux is studied. The excitation probability is shown to be fairly large well below the conventional critical condition. Probability distribution function, as a function of the gradient, for an onset of the transition is obtained both for power law noise. (author)

  16. Transition Metal Compounds Towards Holography

    Directory of Open Access Journals (Sweden)

    Volker Dieckmann

    2012-06-01

    Full Text Available We have successfully proposed the application of transition metal compounds in holographic recording media. Such compounds feature an ultra-fast light-induced linkage isomerization of the transition-metal–ligand bond with switching times in the sub-picosecond regime and lifetimes from microseconds up to hours at room temperature. This article highlights the photofunctionality of two of the most promising transition metal compounds and the photophysical mechanisms that are underlying the hologram recording. We present the latest progress with respect to the key measures of holographic media assembled from transition metal compounds, the molecular embedding in a dielectric matrix and their impressive potential for modern holographic applications.

  17. Optical transitions in semiconductor nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Rupasov, Valery I. [ALTAIR Center LLC, Shrewsbury, MA 01545 (United States) and Landau Institute for Theoretical Physics, Moscow (Russian Federation)]. E-mail: rupasov@townisp.com

    2007-03-19

    Employing the Maxwell equations and conventional boundary conditions for the radiation field on the nanostructure interfaces, we compute the radiative spontaneous decay rate of optical transitions in spherical semiconductor nanocrystals, core-shell nanocrystals and nanostructures comprising more than one shell. We also show that the coupling between optical transitions localized in the shell of core-shell nanocrystals and radiation field is determined by both conventional electro-multipole momenta and electro-multipole 'inverse' momenta. The latter are proportional to the core radius even for interband transitions that should result in very strong optical transitions.

  18. Structural Transition in Supercritical Fluids

    Directory of Open Access Journals (Sweden)

    Boris I. Sedunov

    2011-01-01

    Full Text Available The extension of the saturation curve ( on the PT diagram in the supercritical region for a number of monocomponent supercritical fluids by peak values for different thermophysical properties, such as heat capacities and and compressibility has been studied. These peaks signal about some sort of fluid structural transition in the supercritical region. Different methods give similar but progressively diverging curves st( for this transition. The zone of temperatures and pressures near these curves can be named as the zone of the fluid structural transition. The outstanding properties of supercritical fluids in this zone help to understand the physical sense of the fluid structural transition.

  19. Diverse types of percolation transitions

    Science.gov (United States)

    Lee, Deokjae; Cho, Y. S.; Kahng, B.

    2016-12-01

    Percolation has long served as a model for diverse phenomena and systems. The percolation transition, that is, the formation of a giant cluster on a macroscopic scale, is known as one of the most robust continuous transitions. Recently, however, many abrupt percolation transitions have been observed in complex systems. To illustrate such phenomena, considerable effort has been made to introduce models and construct theoretical frameworks for explosive, discontinuous, and hybrid percolation transitions. Experimental results have also been reported. In this review article, we describe such percolation models, their critical behaviors and universal features, and real-world phenomena.

  20. Diverse types of percolation transitions

    CERN Document Server

    Lee, Deokjae; Kahng, Byungnam

    2016-01-01

    Percolation has long served as a model for diverse phenomena and systems. The percolation transition, that is, the formation of a giant cluster on a macroscopic scale, is known as one of the most robust continuous transitions. Recently, however, many abrupt percolation transitions have been observed in complex systems. To illustrate such phenomena, considerable effort has been made to introduce models and construct theoretical frameworks for explosive, discontinuous, and hybrid percolation transitions. Experimental results have also been reported. In this review article, we describe such percolation models, their critical behaviors and universal features, and real-world phenomena.

  1. Innovation policy for the Dutch energy transition Operationalising transition management?

    NARCIS (Netherlands)

    D.A. Loorbach (Derk); R. Kemp (René)

    2005-01-01

    textabstractThe term transition is a key term of the fourth national environmental policy plan (NMP4, 2001), which put forward transition management (Rotmans et al, 2000) as a new policy approach for dealing with persistent and highly complex societal problems such as climate change, loss of biodive

  2. Light Scattering in Exoplanet Transits

    Science.gov (United States)

    Robinson, Tyler D.; Fortney, Jonathan J.

    2016-10-01

    Transit spectroscopy is currently the leading technique for studying exoplanet atmospheric composition, and has led to the detection of molecular species, clouds, and/or hazes for numerous worlds outside the Solar System. The field of exoplanet transit spectroscopy will be revolutionized with the anticipated launch of NASA's James Webb Space Telescope (JWST) in 2018. Over the course of the design five year mission for JWST, the observatory is expected to provide in-depth observations of many tens of transiting exoplanets, including some worlds in the poorly understood 2-4 Earth-mass regime. As the quality of transit spectrum observations continues to improve, so should models of exoplanet transits. Thus, certain processes initially thought to be of second-order importance should be revisited and possibly added to modeling tools. For example, atmospheric refraction, which was commonly omitted from early transit spectrum models, has recently been shown to be of critical importance in some terrestrial exoplanet transits. Beyond refraction, another process that has seen little study with regards to exoplanet transits is light multiple scattering. In most cases, scattering opacity in exoplanet transits has been treated as equivalent to absorption opacity. However, this equivalence cannot always hold, such as in the case of a strongly forward scattering, weakly absorbing aerosol. In this presentation, we outline a theory of exoplanet transit spectroscopy that spans the geometric limit (used in most modern models) to a fully multiple scattering approach. We discuss a new technique for improving model efficiency that effectively separates photon paths, which tend to vary slowly in wavelength, from photon absorption, which can vary rapidly in wavelength. Using this newly developed approach, we explore situations where cloud or haze scattering may be important to JWST observations of gas giants, and comment on the conditions necessary for scattering to become a major

  3. New graduate nurses in transition

    DEFF Research Database (Denmark)

    Tingleff, Ellen Boldrup; Gildberg, Frederik Alkier

    2014-01-01

    Research on experiences of transition into mental health-care roles seems sparse, but it is vital in order to produce a comprehensive understanding of the transition into mental health-care roles and to serve as a foundation for future research and development. The aim of the present study was to...

  4. Homological Type of Geometric Transitions

    CERN Document Server

    Rossi, Michele

    2010-01-01

    The present paper gives an account and quantifies the change in topology induced by small and type II geometric transitions, by introducing the notion of the \\emph{homological type} of a geometric transition. The obtained results agree with, and go further than, most results and estimates, given to date by several authors, both in mathematical and physical literature.

  5. Transition management: origin, evolution, critique

    NARCIS (Netherlands)

    J. Rotmans (Jan); D.A. Loorbach (Derk); R. Kemp (René)

    2007-01-01

    textabstractTransition management has rapidly emerged over the past few years as a new approach to dealing with complex societal problems and governance in the context of these problems. In the Netherland, UK and Belgium, serious efforts have been and are being undertaken to develop transition polic

  6. Water drives peptide conformational transitions

    CERN Document Server

    Nerukh, Dmitry

    2011-01-01

    Transitions between metastable conformations of a dipeptide are investigated using classical molecular dynamics simulation with explicit water molecules. The distribution of the surrounding water at different moments before the transitions and the dynamical correlations of water with the peptide's configurational motions indicate that water is the main driving force of the conformational changes.

  7. Bayesian priors for transiting planets

    CERN Document Server

    Kipping, David M

    2016-01-01

    As astronomers push towards discovering ever-smaller transiting planets, it is increasingly common to deal with low signal-to-noise ratio (SNR) events, where the choice of priors plays an influential role in Bayesian inference. In the analysis of exoplanet data, the selection of priors is often treated as a nuisance, with observers typically defaulting to uninformative distributions. Such treatments miss a key strength of the Bayesian framework, especially in the low SNR regime, where even weak a priori information is valuable. When estimating the parameters of a low-SNR transit, two key pieces of information are known: (i) the planet has the correct geometric alignment to transit and (ii) the transit event exhibits sufficient signal-to-noise to have been detected. These represent two forms of observational bias. Accordingly, when fitting transits, the model parameter priors should not follow the intrinsic distributions of said terms, but rather those of both the intrinsic distributions and the observational ...

  8. México: elected transition

    Directory of Open Access Journals (Sweden)

    Mauricio MERINO HUERTA

    2010-10-01

    Full Text Available The results of the Mexican federal elections of July 2000 raised new questions for those interested in transitions. In contrast to the South American, East-European, and South European experiences –that have produced a rich literature on the subject–, political changes in Mexico are not easily placed within the existing theoretical frameworks. This paper aims at contrasting the ideal model of transition and the real Mexican transition. The argument focuses on three differences: instead of a transition based on pact –as suggested by theory– this has been a transition based on voting. Moreover, there has not been –as in other cases— a breaking point with the previous regime, but a gradual and continuous opening. Finally, rather than a transformation of the rules of the game, what has taken place is a recovery of formal institutions, not the design of new ones.

  9. Transitive Reduction of Citation Networks

    CERN Document Server

    Clough, James R; Loach, Tamar V; Evans, Tim S

    2013-01-01

    Citation networks form directed acyclic graphs. The transitive reduction of such a DAG removes all edges in the graph that are implied by transitivity, but retains the causal structure of the original network. We investigate how the degree distribution, clustering coefficients and relationship between time of publication and degree (representing citation count) are changed under transitive reduction. We show that models which accurately reproduce the degree distribution of a citation network before transitive reduction may not do so afterwards and hence suggest that these models fail to accurately capture the causal structure of the network. We also investigate how the citation count of individual papers is changed and suggest that information about the types of citations a paper receives can be inferred from the number of citations which are retained after transitive reduction. These methods are tested on citation networks from the hep-th and hep-ph sections of the arXiv repository, and all data has been mad...

  10. Narratives about labour market transitions

    DEFF Research Database (Denmark)

    Cort, Pia; Thomsen, Rie

    2014-01-01

    on flexicurity and its implications for labour market transitions, little attention has been paid to the views and experiences of the individuals concerned. The aim of this article is to connect the grand narrative with individual narratives about labour market transitions in the Danish flexicurity system....... On the basis of narrative interviews with skilled workers, this article explores how labour market transitions are experienced by the individual and the role played by national support structures in the individual narratives. The article shows how, for the individual, a transition may prove to be a valuable...... learning experience during which radical career decisions are taken, and how support structures may work to the detriment of such learning and of the principles behind flexicurity. The article points to a reconceptualisation of transitions as important learning opportunities during which (more) adequate...

  11. Multiobjective Optimization and Phase Transitions

    CERN Document Server

    Seoane, Luís F

    2015-01-01

    Many complex systems obey to optimality conditions that are usually not simple. Conflicting traits often interact making a Multi Objective Optimization (MOO) approach necessary. Recent MOO research on complex systems report about the Pareto front (optimal designs implementing the best trade-off) in a qualitative manner. Meanwhile, research on traditional Simple Objective Optimization (SOO) often finds phase transitions and critical points. We summarize a robust framework that accounts for phase transitions located through SOO techniques and indicates what MOO features resolutely lead to phase transitions. These appear determined by the shape of the Pareto front, which at the same time is deeply related to the thermodynamic Gibbs surface. Indeed, thermodynamics can be written as an MOO from where its phase transitions can be parsimoniously derived; suggesting that the similarities between transitions in MOO-SOO and Statistical Mechanics go beyond mere coincidence.

  12. Non-equilibrium phase transitions

    CERN Document Server

    Henkel, Malte; Lübeck, Sven

    2009-01-01

    This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.

  13. 22 CFR 41.71 - Transit aliens.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Transit aliens. 41.71 Section 41.71 Foreign... NATIONALITY ACT, AS AMENDED Transit Aliens § 41.71 Transit aliens. (a) Transit aliens—general. An alien is classifiable as a nonimmigrant transit alien under INA 101(a) (15) (C) if the consular officer is...

  14. Uniformly convex-transitive function spaces

    OpenAIRE

    Rambla-Barreno, Fernando; Talponen, Jarno

    2009-01-01

    We introduce a property of Banach spaces called uniform convex-transitivity, which falls between almost transitivity and convex-transitivity. We will provide examples of uniformly convex-transitive spaces. This property behaves nicely in connection with some Banach-valued function spaces. As a consequence, we obtain new examples of convex-transitive Banach spaces.

  15. Democratic transition and foreign direct investment: Transition process matters

    OpenAIRE

    Derbali, Ahmed; Trabelsi Masmoudi, Lilia; Zitouna, Habib

    2015-01-01

    This paper provides evidence on the relationship between foreign direct investment (FDI) and democratic transition. We propose first an econometric analysis of the determinants of the democratization process through a "probit" model. We consider a sample of 173 countries, with 44 that have experienced a democratic transition over the period 1980-2010. Our results reveal that variables related to human development and individual freedom facilitate the initiation of the democratic process in co...

  16. Analysis of unique beta transitions

    DEFF Research Database (Denmark)

    Eman, B.; Krmpotic, F.; Tadic, D;

    1967-01-01

    The Heidelberg group measurements [For abstr. see Phys. Rev. Nucl. Sci. Vol. 15 (1965)] of unique forbidden transitions have been analysed. It has been found that experimental shape factors can be reproduced only with the induced pseudoscalar form factor d ...-non-conserving tensor form factor b > 0. In the former case they contradict Daniel's results [See abstr. 1966A10720] for 0- rarr 0+ transitions, whereas in the latter they are in disagreement with other known analyses of mu-meson capture, allowed and forbidden transitions. The conclusion appears to be independent...

  17. Magnetic resonance of phase transitions

    CERN Document Server

    Owens, Frank J; Farach, Horacio A

    1979-01-01

    Magnetic Resonance of Phase Transitions shows how the effects of phase transitions are manifested in the magnetic resonance data. The book discusses the basic concepts of structural phase and magnetic resonance; various types of magnetic resonances and their underlying principles; and the radiofrequency methods of nuclear magnetic resonance. The text also describes quadrupole methods; the microwave technique of electron spin resonance; and the Mössbauer effect. Phase transitions in various systems such as fluids, liquid crystals, and crystals, including paramagnets and ferroelectrics, are also

  18. Controlled quantum evolutions and transitions

    Energy Technology Data Exchange (ETDEWEB)

    Petroni, Nicola Cufaro [INFN Sezione di Bari, INFM Unitadi Bari and Dipartimento Interateneo di Fisica dell' Universitae del Politecnico di Bari, Bari (Italy); De Martino, Salvatore; De Siena, Silvio; Illuminati, Fabrizio [INFM Unitadi Salerno, INFN Sezione di Napoli - Gruppo collegato di Salerno and Dipartimento di Fisica dell' Universitadi Salerno, Baronissi, Salerno (Italy)

    1999-10-29

    We study the nonstationary solutions of Fokker-Planck equations associated to either stationary or non stationary quantum states. In particular, we discuss the stationary states of quantum systems with singular velocity fields. We introduce a technique that allows arbitrary evolutions ruled by these equations to account for controlled quantum transitions. As a first significant application we present a detailed treatment of the transition probabilities and of the controlling time-dependent potentials associated to the transitions between the stationary, the coherent, and the squeezed states of the harmonic oscillator. (author)

  19. Controlled quantum evolutions and transitions

    CERN Document Server

    Petroni, N C; De Siena, S; Illuminati, F

    1999-01-01

    We study the nonstationary solutions of Fokker-Planck equations associated to either stationary or nonstationary quantum states. In particular we discuss the stationary states of quantum systems with singular velocity fields. We introduce a technique that allows to realize arbitrary evolutions ruled by these equations, to account for controlled quantum transitions. The method is illustrated by presenting the detailed treatment of the transition probabilities and of the controlling time-dependent potentials associated to the transitions between the stationary, the coherent, and the squeezed states of the harmonic oscillator. Possible extensions to anharmonic systems and mixed states are briefly discussed and assessed.

  20. METABALL-BASED TRANSITION SURFACES

    Institute of Scientific and Technical Information of China (English)

    Li Lingfeng; Tan Jianrong; Chen Yuanpeng

    2005-01-01

    Metaball-based constraint deformation technique is used to change the definition of r, the straight-line distance from a space point to a constraint center in the original calculation of the potential function. By replacing the parameter of the parametrized surface w with the straight-line distance r, a method of building transition surfaces according to connected boundary curves and skeleton curves is proposed. The method has no restrictions on boundary curves that control the space shapes of transition surfaces or on types of skeleton curves, thus transition surfaces, which reach C1 continuity and are more abundant in shapes and natural, can be obtained.

  1. Transition to turbulence in pipe flow as a phase transition

    Science.gov (United States)

    Vasudevan, Mukund; Hof, Björn

    2015-11-01

    In pipe flow, turbulence first arises in the form of localized turbulent patches called puffs. The flow undergoes a transition to sustained turbulence via spatio-temporal intermittency, with puffs splitting, decaying and merging in the background laminar flow. However, the due to mean advection of the puffs and the long timescales involved (~107 advective time units), it is not possible to study the transition in typical laboratory set-ups. So far, it has only been possible to indirectly estimate the critical point for the transition. Here, we exploit the stochastic memoryless nature of the puff decay and splitting processes to construct a pipe flow set-up, that is periodic in a statistical sense. It then becomes possible to study the flow for sufficiently long times and characterize the transition in detail. We present measurements of the turbulent fraction as a function of Reynolds number which in turn allows a direct estimate of the critical point. We present evidence that the transition has features of a phase transition of second order.

  2. Mechanical Behaviour of Materials Volume II Fracture Mechanics and Damage

    CERN Document Server

    François, Dominique; Zaoui, André

    2013-01-01

    Designing new structural materials, extending lifetimes and guarding against fracture in service are among the preoccupations of engineers, and to deal with these they need to have command of the mechanics of material behaviour. This ought to reflect in the training of students. In this respect, the first volume of this work deals with elastic, elastoplastic, elastoviscoplastic and viscoelastic behaviours; this second volume continues with fracture mechanics and damage, and with contact mechanics, friction and wear. As in Volume I, the treatment links the active mechanisms on the microscopic scale and the laws of macroscopic behaviour. Chapter I is an introduction to the various damage phenomena. Chapter II gives the essential of fracture mechanics. Chapter III is devoted to brittle fracture, chapter IV to ductile fracture and chapter V to the brittle-ductile transition. Chapter VI is a survey of fatigue damage. Chapter VII is devoted to hydogen embrittlement and to environment assisted cracking, chapter VIII...

  3. Empowering Students in Transition

    Science.gov (United States)

    Sullivan, Ann-Catherine

    2016-01-01

    The purpose of this study was to (a) identify potential benefits for students with disabilities taking part in a physical activity program with same-age typical peers on a Midwest university campus and (b) to determine if the program impacted the students with disabilities empowerment. Empowerment theory was used to determine how transition students’ attitudes change over the course of the semester while participating in a workout buddy program with same-age college peers. The program was structured to provide a sense of empowerment to students to make their own decisions and learn for themselves so they do not feel a lack of power in their lives. This study implemented elements of a quantitative design but a majority utilized a qualitative design based on the assumptions of the Interpretivist paradigm. The quantitative design elements focused on the analysis of two questionnaires: Sports Questionnaire and the Perceived Control Scale Questionnaire. The analysis of the focus group data revealed the following themes as positive effects of the intervention: positive effect on empowerment, how happy the program made the students, what benefits the students gained from the program, the student’s familiarity with university students, and the environment, and, lastly, the students ability to ask for assistance when need. Findings from the study determined that the empowerment of the students with disabilities was impacted while participating in the program. In general, the findings of gaining empowerment were similar to previous studies in that students with disabilities are able to gain empowerment from participation in fitness and recreation programs. The researcher noted during focus groups that some of the Best of Both Worlds (BOBW) students were not confident in starting conversations with their university peers. Although the BOBW students felt a sense of losing empowerment with this specific instance, there was an overall positive impact on the BOBW students

  4. Hybrid percolation transition in complex networks

    Science.gov (United States)

    Kahng, Byungnam

    Percolation has been one of the most applied statistical models. Percolation transition is one of the most robust continuous transitions known thus far. However, recent extensive researches reveal that it exhibits diverse types of phase transitions such as discontinuous and hybrid phase transitions. Here hybrid phase transition means the phase transition exhibiting natures of both continuous and discontinuous phase transitions simultaneously. Examples include k-core percolation, cascading failures in interdependent networks, synchronization, etc. Thus far, it is not manifest if the critical behavior of hybrid percolation transitions conforms to the conventional scaling laws of second-order phase transition. Here, we investigate the critical behaviors of hybrid percolation transitions in the cascading failure model in inter-dependent networks and the restricted Erdos-Renyi model. We find that the critical behaviors of the hybrid percolation transitions contain some features that cannot be described by the conventional theory of second-order percolation transitions.

  5. Percolation transitions with nonlocal constraint.

    Science.gov (United States)

    Shim, Pyoung-Seop; Lee, Hyun Keun; Noh, Jae Dong

    2012-09-01

    We investigate percolation transitions in a nonlocal network model numerically. In this model, each node has an exclusive partner and a link is forbidden between two nodes whose r-neighbors share any exclusive pair. The r-neighbor of a node x is defined as a set of at most N(r) neighbors of x, where N is the total number of nodes. The parameter r controls the strength of a nonlocal effect. The system is found to undergo a percolation transition belonging to the mean-field universality class for r1/2, the system undergoes a peculiar phase transition from a nonpercolating phase to a quasicritical phase where the largest cluster size G scales as G~N(α) with α=0.74(1). In the marginal case with r=1/2, the model displays a percolation transition that does not belong to the mean-field universality class.

  6. Deconfining transition in Full QCD

    CERN Document Server

    Carmona, J M; Del Debbio, L; Di Giacomo, Adriano; Lucini, B; Paffuti, G; Pica, C

    2002-01-01

    We present evidence that in full QCD with two dynamical quarks confinement is produced by dual superconductivity of the vacuum as in the quenched theory. Preliminary information is obtained on the nature of the deconfining transition.

  7. The plasma-solid transition

    CERN Document Server

    Celebonovic, V

    2001-01-01

    Using a criterion proposed by Salpeter and standard solid-state physics,we have determined conditions for the occurence of the plasma-solid transition.Possible astrophysical applications are discussed.

  8. Transition metals in carbohydrate chemistry

    DEFF Research Database (Denmark)

    Madsen, Robert

    1997-01-01

    This review describes the application of transition metal mediated reactions in carbohydrate synthesis. The different metal mediated transformations are divided into reaction types and illustrated by various examples on monosaccharide derivatives. Carbon-carbon bond forming reactions are further ...

  9. The RN to BSN Transition

    Directory of Open Access Journals (Sweden)

    Allison Brandt Anbari

    2015-11-01

    Full Text Available Approximately 60% of registered nurses (RNs still enter practice with an associate’s degree or diploma in nursing (ADN. Due to recommendations to change entry level to practice to the bachelor’s degree in nursing (BSN, there are now more than 700 RN to BSN programs in the United States. The purpose of this qualitative systematic review was to understand more about what occurs when an RN returns to school for a BSN and to develop a model of the transition. The qualitative findings of 19 research reports were included, which translates to approximately 445 RNs’ perspectives on the RN to BSN transition. A visual representation of the RN to BSN transition was also generated. A seamless transition of the RN to a BSN does not exist at this time. The results are useful to nurses, academicians, and health care organizations as they move to meet current recommendations.

  10. Vessels in Transit - Web Tool

    Data.gov (United States)

    Department of Transportation — A web tool that provides real-time information on vessels transiting the Saint Lawrence Seaway. Visitors may sort by order of turn, vessel name, or last location in...

  11. Classical Transitions for Flux Vacua

    CERN Document Server

    Deskins, J Tate; Yang, I-Sheng

    2012-01-01

    We present the simplest model for classical transitions in flux vacua. A complex field with a spontaneously broken U(1) symmetry is embedded in $M_2\\times S_1$. We numerically construct different winding number vacua, the vortices interpolating between them, and simulate the collisions of these vortices. We show that classical transitions are generic at large boosts, independent of whether or not vortices miss each other in the compact $S_1$.

  12. Transitions in turbulent rotating convection

    Science.gov (United States)

    Rajaei, Hadi; Alards, Kim; Kunnen, Rudie; Toschi, Federico; Clercx, Herman; Fluid Dynamics Lab Team

    2015-11-01

    This study aims to explore the flow transition from one state to the other in rotating Rayleigh-Bènard convection using Lagrangian acceleration statistics. 3D particle tracking velocimetry (3D-PTV) is employed in a water-filled cylindrical tank of equal height and diameter. The measurements are performed at the center and close to the top plate at a Rayleigh number Ra = 1.28e9 and Prandtl number Pr = 6.7 for different rotation rates. In parallel, direct numerical simulation (DNS) has been performed to provide detailed information on the boundary layers. We report the acceleration pdfs for different rotation rates and show how the transition from weakly to strongly rotating Rayleigh-Bènard affects the acceleration pdfs in the bulk and boundary layers. We observe that the shapes of the acceleration PDFs as well as the isotropy in the cell center are largely unaffected while crossing the transition point. However, acceleration pdfs at the top show a clear change at the transition point. Using acceleration pdfs and DNS data, we show that the transition between turbulent states is actually a boundary layer transition between Prandtl-Blasius type (typical of non-rotating convection) and Ekman type.

  13. Boundary layer transition studies

    Science.gov (United States)

    Watmuff, Jonathan H.

    1995-02-01

    A small-scale wind tunnel previously used for turbulent boundary layer experiments was modified for two sets of boundary layer transition studies. The first study concerns a laminar separation/turbulent reattachment. The pressure gradient and unit Reynolds number are the same as the fully turbulent flow of Spalart and Watmuff. Without the trip wire, a laminar layer asymptotes to a Falkner & Skan similarity solution in the FPG. Application of the APG causes the layer to separate and a highly turbulent and approximately 2D mean flow reattachment occurs downstream. In an effort to gain some physical insight into the flow processes a small impulsive disturbance was introduced at the C(sub p) minimum. The facility is totally automated and phase-averaged data are measured on a point-by-point basis using unprecedently large grids. The evolution of the disturbance has been tracked all the way into the reattachment region and beyond into the fully turbulent boundary layer. At first, the amplitude decays exponentially with streamwise distance in the APG region, where the layer remains attached, i.e. the layer is viscously stable. After separation, the rate of decay slows, and a point of minimum amplitude is reached where the contours of the wave packet exhibit dispersive characteristics. From this point, exponential growth of the amplitude of the disturbance is observed in the detached shear layer, i.e. the dominant instability mechanism is inviscid. A group of large-scale 3D vortex loops emerges in the vicinity of the reattachment. Remarkably, the second loop retains its identify far downstream in the turbulent boundary layer. The results provide a level of detail usually associated with CFD. Substantial modifications were made to the facility for the second study concerning disturbances generated by Suction Holes for laminar flow Control (LFC). The test section incorporates suction through interchangeable porous test surfaces. Detailed studies have been made using isolated

  14. Transition boiling heat transfer and the film transition regime

    Science.gov (United States)

    Ramilison, J. M.; Lienhard, J. H.

    1987-01-01

    The Berenson (1960) flat-plate transition-boiling experiment has been recreated with a reduced thermal resistance in the heater, and an improved access to those portions of the transition boiling regime that have a steep negative slope. Tests have been made in Freon-113, acetone, benzene, and n-pentane boiling on horizontal flat copper heaters that have been mirror-polished, 'roughened', or teflon-coated. The resulting data reproduce and clarify certain features observed by Berenson: the modest surface finish dependence of boiling burnout, and the influence of surface chemistry on both the minimum heat flux and the mode of transition boiling, for example. A rational scheme of correlation yields a prediction of the heat flux in what Witte and Lienhard (1982) previously identified as the 'film-transition boiling' region. It is also shown how to calculate the heat flux at the boundary between the pure-film, and the film-transition, boiling regimes, as a function of the advancing contact angle.

  15. GATE (Gaia Transiting Exoplanets): Detecting Transiting Exoplanets with Gaia

    Science.gov (United States)

    Zucker, Shay; Eyer, Laurent; Hodgkin, Simon; Clementini, Gisella

    2016-10-01

    Gaia will have a revolutionary impact on most fields of astronomy. However, its scanning law is too sparse for traditional transit detection approaches (de Bruijne 2012). Practically, only stars brighter than 16th magnitude are relevant for follow-up of transiting exoplanets. For those stars, Gaia's precision is of the order of 1 mmag (Eyer et al. 2015). On average, Gaia will have sampled each target 70 times, but certain stars may be observed as many as 200 times (Voss et al. 2013). Hipparcos scanning law was similar, but its precision much worse. Nevertheless the transit of HD209458 could be seen, aposteriori, in Hipparcos' data (Söderhelm 1999). This inspired our GATE initiative.

  16. Transit fare prepayment: A guide for transit managers. Research report

    Energy Technology Data Exchange (ETDEWEB)

    Mayworm, P.D.; Lago, A.M.

    1983-01-04

    Transit fare prepayment programs grew rapidly during the past decade with most companies today offering riders several prepayment options. The growth has not been without its costs. The manual provides transit managers with the information and tools necessary to make informed decisions on the design and pricing of fare prepayment plans. Included is information on the true benefits and costs of operating fare prepayment plans. Guidelines on selecting the appropriate plans and distribution methods are presented, as are guidelines on pricing fare prepayment plans in order to capture passenger revenues. A series of straightforward equations are also provided to assist the transit manager in estimating the impacts of changes in a fare prepayment program. The report contains a glossary of terms, a bibliography and a discussion of some fare prepayment demonstration projects.

  17. Transition risk method and example

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, R.E. [Westinghouse Electric Company, Monroeville PA (United States); Farkas, S.E. [Hudson Global Resources (United States)

    2004-07-01

    Paragraph (a)(4) of the Maintenance Rule (10CFR-50.65) states that before performing maintenance activities, the licensees shall assess and manage the increase in risk that may result from the maintenance activities. Currently, most plants use a qualitative tool for assessing and controlling the risk of the various plant conditions during an outage. Fewer plants have any means of performing a quantitative or qualitative assessment of the associated risks of transitioning the plant in each configuration from power to 'cold shutdown'. Typically, only the end-state of shutdown is considered. Given the concern that the NRC may require quantitative risk assessments of plant transitions and plant configurations during shutdown operations, Omaha Public Power District (OPPD) pro-actively authorized Westinghouse Engineering Services to develop a method for assessing risk associated with a transition from all power to shutdown and back to full power. An outage schedule is highly plant specific. Accordingly, the duration of the transition largely depends on equipment maintenance activities driving the decision to shutdown and repair. The time spent in various parts of the transition is a strong determinant in the associated risk of the transition. A transition takes the plant through a series of Plant Operational States (POSs). The features important to the characterization of each of the POSs include decay-heat level, plant activities involved, available equipment, as well as RCS temperature and pressure. The risk of the entire transition comes from calculating a figure-of-merit of each POS which can be loosely thought of as a per-hour core-damage frequency (CDF). Our paper describes decomposing OPPD operating procedures into periods for which we quantified sequences. In particular, the method considers the dominant shutdown failure modes: loss of shutdown cooling, loss of inventory, and loss of offsite power (including both plant centered and grid-related events

  18. Major transitions in human evolution

    Science.gov (United States)

    Foley, Robert A.; Martin, Lawrence; Mirazón Lahr, Marta; Stringer, Chris

    2016-01-01

    Evolutionary problems are often considered in terms of ‘origins', and research in human evolution seen as a search for human origins. However, evolution, including human evolution, is a process of transitions from one state to another, and so questions are best put in terms of understanding the nature of those transitions. This paper discusses how the contributions to the themed issue ‘Major transitions in human evolution’ throw light on the pattern of change in hominin evolution. Four questions are addressed: (1) Is there a major divide between early (australopithecine) and later (Homo) evolution? (2) Does the pattern of change fit a model of short transformations, or gradual evolution? (3) Why is the role of Africa so prominent? (4) How are different aspects of adaptation—genes, phenotypes and behaviour—integrated across the transitions? The importance of developing technologies and approaches and the enduring role of fieldwork are emphasized. This article is part of the themed issue ‘Major transitions in human evolution’. PMID:27298461

  19. The major synthetic evolutionary transitions

    Science.gov (United States)

    Solé, Ricard

    2016-01-01

    Evolution is marked by well-defined events involving profound innovations that are known as ‘major evolutionary transitions'. They involve the integration of autonomous elements into a new, higher-level organization whereby the former isolated units interact in novel ways, losing their original autonomy. All major transitions, which include the origin of life, cells, multicellular systems, societies or language (among other examples), took place millions of years ago. Are these transitions unique, rare events? Have they instead universal traits that make them almost inevitable when the right pieces are in place? Are there general laws of evolutionary innovation? In order to approach this problem under a novel perspective, we argue that a parallel class of evolutionary transitions can be explored involving the use of artificial evolutionary experiments where alternative paths to innovation can be explored. These ‘synthetic’ transitions include, for example, the artificial evolution of multicellular systems or the emergence of language in evolved communicating robots. These alternative scenarios could help us to understand the underlying laws that predate the rise of major innovations and the possibility for general laws of evolved complexity. Several key examples and theoretical approaches are summarized and future challenges are outlined. This article is part of the themed issue ‘The major synthetic evolutionary transitions’. PMID:27431528

  20. Electromechanical transition in quantum dots

    Science.gov (United States)

    Micchi, G.; Avriller, R.; Pistolesi, F.

    2016-09-01

    The strong coupling between electronic transport in a single-level quantum dot and a capacitively coupled nanomechanical oscillator may lead to a transition towards a mechanically bistable and blocked-current state. Its observation is at reach in carbon-nanotube state-of-art experiments. In a recent publication [Phys. Rev. Lett. 115, 206802 (2015), 10.1103/PhysRevLett.115.206802] we have shown that this transition is characterized by pronounced signatures on the oscillator mechanical properties: the susceptibility, the displacement fluctuation spectrum, and the ring-down time. These properties are extracted from transport measurements, however the relation between the mechanical quantities and the electronic signal is not always straightforward. Moreover the dependence of the same quantities on temperature, bias or gate voltage, and external dissipation has not been studied. The purpose of this paper is to fill this gap and provide a detailed description of the transition. Specifically we find (i) the relation between the current-noise and the displacement spectrum; (ii) the peculiar behavior of the gate-voltage dependence of these spectra at the transition; (iii) the robustness of the transition towards the effect of external fluctuations and dissipation.

  1. Young Exoplanet Transit Initiative (YETI)

    CERN Document Server

    Neuhäuser, R; Berndt, A; Maciejewski, G; Takahashi, H; Chen, W P; Dimitrov, D P; Pribulla, T; Nikogossian, E H; Jensen, E L N; Marschall, L; Wu, Z -Y; Kellerer, A; Walter, F M; Briceño, C; Chini, R; Fernandez, M; Raetz, St; Torres, G; Latham, D W; Quinn, S N; Niedzielski, A; Bukowiecki, Ł; Nowak, G; Tomov, T; Tachihara, K; Hu, S C -L; Hung, L W; Radeva, D P Kjurkchieva \\and V S; Mihov, B M; Slavcheva-Mihova, L; Bozhinova, I N; Budaj, J; Vaňko, M; Kundra, E; Hambálek, Ľ; Krushevska, V; Movsessian, T; Harutyunyan, H; Downes, J J; Hernandez, J; Hoffmeister, V H; Cohen, D H; Abel, I; Ahmad, R; Chapman, S; Eckert, S; Goodman, J; Guerard, A; Kim, H M; Koontharana, A; Sokol, J; Trinh, J; Wang, Y; Zhou, X; Redmer, R; Kramm, U; Nettelmann, N; Mugrauer, M; Schmidt, J; Moualla, M; Ginski, C; Marka, C; Adam, C; Seeliger, M; Baar, S; Roell, T; Schmidt, T O B; Trepl, L; Eisenbei\\ss, T; Fiedler, S; Tetzlaff, N; Schmidt, E; Hohle, M M; Kitze, M; Chakrova, N; Gräfe, C; Schreyer, K; Hambaryan, V V; Broeg, C H; Koppenhoefer, J; Pandey, A K

    2011-01-01

    We present the Young Exoplanet Transit Initiative (YETI), in which we use several 0.2 to 2.6m telescopes around the world to monitor continuously young (< 100 Myr), nearby (< 1 kpc) stellar clusters mainly to detect young transiting planets (and to study other variability phenomena on time-scales from minutes to years). The telescope network enables us to observe the targets continuously for several days in order not to miss any transit. The runs are typically one to two weeks long, about three runs per year per cluster in two or three subsequent years for about ten clusters. There are thousands of stars detectable in each field with several hundred known cluster members, e.g. in the first cluster observed, Tr-37, a typical cluster for the YETI survey, there are at least 469 known young stars detected in YETI data down to R=16.5 mag with sufficient precision of 50 milli-mag rms (5 mmag rms down to R=14.5 mag) to detect transits, so that we can expect at least about one young transiting object in this cl...

  2. Observation of optomechanical buckling transitions

    Science.gov (United States)

    Xu, H.; Kemiktarak, U.; Fan, J.; Ragole, S.; Lawall, J.; Taylor, J. M.

    2017-03-01

    Correlated phases of matter provide long-term stability for systems as diverse as solids, magnets and potential exotic quantum materials. Mechanical systems, such as buckling transition spring switches, can have engineered, stable configurations whose dependence on a control variable is reminiscent of non-equilibrium phase transitions. In hybrid optomechanical systems, light and matter are strongly coupled, allowing engineering of rapid changes in the force landscape, storing and processing information, and ultimately probing and controlling behaviour at the quantum level. Here we report the observation of first- and second-order buckling transitions between stable mechanical states in an optomechanical system, in which full control of the nature of the transition is obtained by means of the laser power and detuning. The underlying multiwell confining potential we create is highly tunable, with a sub-nanometre distance between potential wells. Our results enable new applications in photonics and information technology, and may enable explorations of quantum phase transitions and macroscopic quantum tunnelling in mechanical systems.

  3. The Structural Phase Transition in Solid DCN

    DEFF Research Database (Denmark)

    Dietrich, O. W.; Mackenzie, Gordon A.; Pawley, G. S.

    1976-01-01

    Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase transition from a tetragonal to an orthorhombic form at 160 K is a first order transition. A transverse acoustic phonon mode, which has the symmetry of the transition was observed at very low energ...... energies and showed “softening” as the transition was approached from above.......Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase transition from a tetragonal to an orthorhombic form at 160 K is a first order transition. A transverse acoustic phonon mode, which has the symmetry of the transition was observed at very low...

  4. Quantum Transition-State Theory

    CERN Document Server

    Hele, Timothy J H

    2014-01-01

    This dissertation unifies one of the central methods of classical rate calculation, `Transition-State Theory' (TST), with quantum mechanics, thereby deriving a rigorous `Quantum Transition-State Theory' (QTST). The resulting QTST is identical to ring polymer molecular dynamics transition-state theory (RPMD-TST), which was previously considered a heuristic method, and whose results we thereby validate. The key step in deriving a QTST is alignment of the flux and side dividing surfaces in path-integral space to obtain a quantum flux-side time-correlation function with a non-zero $t\\to 0_+$ limit. We then prove that this produces the exact quantum rate in the absence of recrossing by the exact quantum dynamics, fulfilling the requirements of a QTST. Furthermore, strong evidence is presented that this is the only QTST with positive-definite Boltzmann statistics and therefore the pre-eminent method for computation of thermal quantum rates in direct reactions.

  5. The Transitional Legend of Winners

    Directory of Open Access Journals (Sweden)

    Ivan Kovačević

    2016-03-01

    Full Text Available During 2006 a number of stories that featured the motive of great gain under dramatic circumstances were repeatedly told in betting-houses in Kragujevac, a town in Serbia. The main character of these legends is an empoverished victim of transition who, thanks to luck and help of friends, wins a great sum of money betting. Besides describing the preceding transitional "fall" of the winner (getting fired, failing in private enterprise, the legends describe his economical and social prosperity initiated by capital gained through betting (starting succesfull enterprises, buying good shares. Diachronically following other "sudden wealth" legends this transitional legend speaks about the establishing of a new system of values that, in the categories of social promotion, makes up for the old principles that marked the period of socialism.

  6. Researching literacy practices in transition

    DEFF Research Database (Denmark)

    Holm, Lars

    Researching literacy practices in transition Postmodern societies are characterized by constant, fast and unpredictable mobility of people, goods, ideas and values. These mobilities are often visualized as a movement from one place to another, as a temporary interference of the stability of fixed...... places. An alternative take on mobilty sees movement as the default and change as the normal way of being rather than the exception (Barton, 2012). This understanding of change is central to the framing concept of this symposium: transition. Transitional processes around literacy are significant because...... literacy is something that is taught and learned, that is adopted, transformed and appropriated and that is used to categorize and classify people (Holm & Pitkänen-Huhta, 2012). Based on detailed empirical studies in the Nordic countries, the aim of this symposium is to discuss how to explore and research...

  7. Political symbols and political transitions

    Directory of Open Access Journals (Sweden)

    Herrero de Miñón, Miguel

    2006-11-01

    Full Text Available Politics, Law and Psychology are fields that come together in the symbolic. This text takes evidence from those three areas to develop an analysis of political symbols and political transitions. The development of the analysis goes through three stages. The first succinctly describes the concept of transition and its meaning. The second closely examines the notion of the symbol, in terms of its definition, to explain aspects that allow us to understand it, characterise it and make its functions clear. Finally, from the author's experience as a witness and as an actor, I suggest three ways of understanding symbols in the processes of political transition: as symbols of change, as symbols of acknowledgment, and as symbols of support.

  8. Sliding Over a Phase Transition

    Science.gov (United States)

    Tosatti, Erio; Benassi, Andrea; Vanossi, Andrea; Santoro, Giuseppe E.

    2011-03-01

    The frictional response experienced by a stick-slip slider when a phase transition occurs in the underlying solid substrate is a potentially exciting, poorly explored problem. We show, based on 2-dimensional simulations modeling the sliding of a nanotip, that indeed friction may be heavily affected by a continuous structural transition. First, friction turns nonmonotonic as temperature crosses the transition, peaking at the critical temperature Tc where fluctuations are strongest. Second, below Tc friction depends upon order parameter directions, and is much larger for those where the frictional slip can cause a local flip. This may open a route towards control of atomic scale friction by switching the order parameter direction by an external field or strain, with possible application to e.g., displacive ferroelectrics such as BaTi O3 , as well as ferro- and antiferro-distortive materials. Supported by project ESF FANAS/AFRI sponsored by the Italian Research Council (CNR).

  9. Trust transitivity in social networks

    CERN Document Server

    Richters, Oliver

    2010-01-01

    Non-centralized recommendation-based decision making is a central feature of several social and technological processes, such as market dynamics, peer-to-peer file-sharing and the web of trust of digital certification. We investigate the properties of trust propagation on networks, based on a simple metric of trust transitivity. We investigate analytically the percolation properties of trust transitivity in random networks with arbitrary degree distribution, and compare with numerical realizations. We find that the existence of a non-zero fraction of absolute trust (i.e. entirely confident trust) is a requirement for the viability of global trust propagation in large systems: The average pair-wise trust is marked by a discontinuous transition at a specific fraction of absolute trust, below which it vanishes. Furthermore, we perform an extensive analysis of the Pretty Good Privacy (PGP) web of trust, in view of the concepts introduced. We compare different scenarios of trust distribution: community- and author...

  10. Towards a sustainable urban transition?

    DEFF Research Database (Denmark)

    Lissandrello, Enza; Cappellaro, Francesca

    2014-01-01

    Never as today the discourse about uncertainty is permeating and affecting traditional paradigms of urban planning. Predictable futures are no longer possible, sufficient to understand it in the long term and adequate. If the future looks uncertain, the debate on sustainable development has...... contributed to render the situation even more complex and planning practitioners are now navigating between an unclear perception of future risks and the hope for results and visions for long-term perspectives of urban futures. Among scholars engaged in the study of sustainable transitions in urban areas...... the challenges for planning urban transitions with an analytic based on how professional practitioners actually think and reflect on a set of projects in view of integral urban planning actions in Bologna. Through a critical reading of transition studies in urban contexts and a dialogue with policy actors...

  11. Comparative Habitability of Transiting Exoplanets

    CERN Document Server

    Barnes, Rory; Evans, Nicole

    2015-01-01

    Exoplanet habitability is traditionally assessed by comparing a planet's semi-major axis to the location of its host star's "habitable zone," the shell around a star for which Earth-like planets can possess liquid surface water. The Kepler space telescope has discovered numerous planet candidates near the habitable zone, and many more are expected from missions such as K2, TESS and PLATO. These candidates often require significant follow-up observations for validation, so prioritizing planets for habitability from transit data has become an important aspect of the search for life in the universe. We propose a method to compare transiting planets for their potential to support life based on transit data, stellar properties and previously reported limits on planetary emitted flux. For a planet in radiative equilibrium, the emitted flux increases with eccentricity, but decreases with albedo. As these parameters are often unconstrained, there is an "eccentricity-albedo degeneracy" for the habitability of transiti...

  12. Power in Transition: Empowering Discourses on Sustainability Transitions

    NARCIS (Netherlands)

    F. Avelino (Flor)

    2011-01-01

    textabstractThis is a book about power and transformative change. It explores how groups of people who are trying to transform the mobility system are affected by notions of change and power, and how they deal with the dilemmas of power. Academic literature on power and transitions offers concepts t

  13. Wetting transition on patterned surfaces: transition states and energy barriers.

    Science.gov (United States)

    Ren, Weiqing

    2014-03-18

    We study the wetting transition on microstructured hydrophobic surfaces. We use the string method [J. Chem. Phys. 2007, 126, 164103; J. Chem. Phys. 2013, 138, 134105] to accurately compute the transition states, the energy barriers, and the minimum energy paths for the wetting transition from the Cassie-Baxter state to the Wenzel state. Numerical results are obtained for the wetting of a hydrophobic surface textured with a square lattice of pillars. It is found that the wetting of the solid substrate occurs via infiltration of the liquid in a single groove, followed by lateral propagation of the liquid front. The propagation of the liquid front proceeds in a stepwise manner, and a zipping mechanism is observed during the infiltration of each layer. The minimum energy path for the wetting transition goes through a sequence of intermediate metastable states, whose wetted areas reflect the microstructure of the patterned surface. We also study the dependence of the energy barrier on the drop size and the gap between the pillars.

  14. Thailand's Work and Health Transition.

    Science.gov (United States)

    Kelly, Matthew; Strazdins, Lyndall; Dellora, Tarie; Khamman, Suwanee; Seubsman, Sam-Ang; Sleigh, Adrian C

    2010-09-01

    Thailand has experienced a rapid economic transition from agriculture to industry and services, and from informal to formal employment. It has much less state regulation and worker representation relative to developed nations, who underwent these transitions more slowly and sequentially, decades earlier. We examine the strengthening of Thai government policy and legislation affecting worker's health, responding to international norms, a new democratic constitution, fear of foreign importer embargos and several fatal workplace disasters. We identify key challenges remaining for Thai policy makers, including legislation enforcement and the measurement of impacts on worker's mental and physical health.

  15. Gendering agency in transitional justice

    DEFF Research Database (Denmark)

    Björkdahl, Annika; Selimovic, Johanna Mannergren

    2015-01-01

    . To address this lacuna we conceptualize and unpack the meaning of gendered agency, by identifying its critical elements and by locating it in space and in time. The conceptual work that we undertake is underpinned by empirical mapping of the transitional justice spaces in post-conflict Bosnia....... Such research enables us to engage with the subjects of post-conflict peacebuilding and transitional justice processes directly and in their own spaces. This article thus renders women’s agency visible and attempts to grasp its contributions and consequences for transformations from war to peace....

  16. Phase transitions and critical phenomena

    CERN Document Server

    Domb, Cyril

    2001-01-01

    The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. It has moved into a central place in condensed matter studies.Statistical physics, and more specifically, the theory of transitions between states of matter, more or less defines what we know about 'everyday' matter and its transformations.The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable in

  17. Effect of petrophysical properties and deformation on vertical zoning of metasomatic rocks in U-bearing volcanic structures: A case of the Strel'tsovka caldera, Transbaikal region

    Science.gov (United States)

    Petrov, V. A.; Andreeva, O. V.; Poluektov, V. V.

    2014-03-01

    The development of vertical zoning of wall-rock metasomatic alteration is considered with the Mesozoic Strel'tsovka caldera as an example. This caldera hosts Russia's largest uranium ore field. Metasomatic rocks with the participation of various phyllosilicates, carbonates, albite, and zeolites are widespread in the ore field. In the eastern block of the caldera, where the main uranium reserves are accommodated, hydromica metasomatic alteration gives way to beresitization with depth. Argillic alteration, which is typical of the western block, is replaced with hydromica and beresite alteration only at a significant depth. Postore argillic alteration is superposed on beresitized rocks in the lower part of the section. Two styles of vertical metasomatic zoning are caused by different modes of deformation in the western and eastern parts of the caldera. Variations of the most important petrophysical properties of host rocks—density, apparent porosity, velocities of P- and S-waves, dynamic Young's modulus, and Poisson coefficient—have been determined by sonic testing of samples taken from different depths. It is suggested that downward migration of the brittle-ductile transition zone could have been a factor controlling facies diversity of metasomatic rocks. Such a migration was caused by a new phase of tectonothermal impact accompanied by an increase in the strain rate or by emplacement of a new portion of heated fluid. Transient subsidence of the brittle-ductile boundary increases the depth of the hydrodynamically open zone related to the Earth's surface and accelerates percolation of cold meteoric water to a greater depth. As a result, the temperature of the hydrothermal solution falls down, increasing the vertical extent of argillic alteration. High-grade uranium mineralization is also localized more deeply than elsewhere.

  18. Phase transitions in finite systems

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph. [Grand Accelerateur National d' Ions Lourds (GANIL), DSM-CEA / IN2P3-CNRS, 14 - Caen (France); Gulminelli, F. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire

    2002-07-01

    In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)

  19. "Mexico in Transition." Curriculum Units.

    Science.gov (United States)

    Oregon Univ., Eugene. Foreign Language Resource Center.

    These curriculum units were developed in a National Endowment for the Humanities 1994 summer seminar "Mexico in Transition." The 23 lessons are written in Spanish. Lessons are entitled: (1) "La Migracion Mexicana Vista a Traves del Cuento 'Paso del Norte' de Juan Rulfo" (Jose Jorge Armendariz); (2) "Los Grupos Indigenas de…

  20. Organizational Transition and Change Resistance

    Directory of Open Access Journals (Sweden)

    Ciprian Nicolescu

    2006-09-01

    Full Text Available The paper focuses on the very important atopic of organizational transition and change resistance. It is divided in four parts. The first part deals with transition inevitability and its content in the change process. The second part of the paper refers to the change resistance. After a short presentation of a recent approach of this topic, elaborated by Rick Maurer, the authors present their point of view, identifying 14 main causes refering to the main factors involved in the organizational transition. In the third part, authors have formulated a set of key elements which should be taken into consideration in order to achieve a rapid and succesful organizational changes. These key elements are valable for any type of organization – entreprise, institution, locality, region, country a.s.a. The last part of the study deals with conflicts approach, which appear almost always during organizational transition. The conflicts are separated in three categories and for whom are presented the methodes recommended in order to solve them with good results.

  1. Finite groups with transitive semipermutability

    Institute of Scientific and Technical Information of China (English)

    Lifang WANG; Yanming WANG

    2008-01-01

    A group G is said to be a T-group (resp. PT-group, PST-group), if normality (resp. permutability, S-permutability) is a transitive relation. In this paper, we get the characterization of finite solvable PST-groups. We also give a new characterization of finite solvable PT-groups.

  2. Transition From Plan to Market

    DEFF Research Database (Denmark)

    Mygind, Niels

    This paper gives an overview over how far transition has proceeded and what is still lacking in the process. The analytical framework – the PIE model for Politics, Institutions, Economy – is introduced. The model is first used to point to the main reasons for the fall of the command economy. Then...

  3. Stress relief of transition zones

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, J.; van Rooyen, D.

    1984-01-01

    This paper considers the problem of intergranular stress corrosion cracking, initiated on the primary side, in the expansion transition region of roller expanded Alloy 600 tubing. In general it is believed that residual stresses, arising from the expansion process, are the cause of the problem. The work reported here concentrated on the identification of an optimal, in-situ stress relief treatment.

  4. Symmetry structure and phase transitions

    Indian Academy of Sciences (India)

    Ashok Goyal; Meenu Dahiya; Deepak Chandra

    2003-05-01

    We study chiral symmetry structure at finite density and temperature in the presence of external magnetic field and gravity, a situation relevant in the early Universe and in the core of compact stars. We then investigate the dynamical evolution of phase transition in the expanding early Universe and possible formation of quark nuggets and their survival.

  5. Poland's Transition in Business Education

    Science.gov (United States)

    Leven, Bozena

    2010-01-01

    Prior to Poland's transition from central planning to a market system, which began in 1990, schools of business were non-existent in that country. Instead, university level instruction on economics during the socialist period was closely tied to ideological priorities, and limited to imparting skills suitable for planned economy. All universities…

  6. Topological transitions in Ising models

    CERN Document Server

    Jalal, Somenath; Lal, Siddhartha

    2016-01-01

    The thermal dynamics of the two-dimensional Ising model and quantum dynamics of the one-dimensional transverse-field Ising model (TFIM) are mapped to one another through the transfer-matrix formalism. We show that the fermionised TFIM undergoes a Fermi-surface topology-changing Lifshitz transition at its critical point. We identify the degree of freedom which tracks the Lifshitz transition via changes in topological quantum numbers (e.g., Chern number, Berry phase etc.). An emergent $SU(2)$ symmetry at criticality is observed to lead to a topological quantum number different from that which characterises the ordered phase. The topological transition is also understood via a spectral flow thought-experiment in a Thouless charge pump, revealing the bulk-boundary correspondence across the transition. The duality property of the phases and their entanglement content are studied, revealing a holographic relation with the entanglement at criticality. The effects of a non-zero longitudinal field and interactions tha...

  7. Transitions in a globalising world

    NARCIS (Netherlands)

    P. Martens (Pim); J. Rotmans (Jan)

    2006-01-01

    textabstractThe increasing complexity of our global society means that sustainable development cannot be addressed from a single perspective or scientific discipline. By using the concept of transitions, we examine current and future tensions between welfare, well-being and the environment, and focu

  8. Phase Transitions of Simple Systems

    CERN Document Server

    Berry, Stephen

    2008-01-01

    This monograph develops a unified microscopic basis for phases and phase changes of bulk matter and small systems in terms of classical physics. The origins of such phase changes are derived from simple but physically relevant models of how transitions between rigid crystalline, glassy and fluid states occur, how phase equilibria arise, and how bulk properties evolve from those of small systems.

  9. Menopause: A Life Cycle Transition.

    Science.gov (United States)

    Evarts, Barbara Kess; Baldwin, Cynthia

    1998-01-01

    Family therapists need to address the issue of menopause proactively to be of benefit to couples and families during this transitional period in the family life cycle. Physical, psychological, and psychosocial factors affecting the menopausal woman and her family, and ways to address these issues in counseling are discussed. (Author/EMK)

  10. The nature of transition blazars

    Energy Technology Data Exchange (ETDEWEB)

    Ruan, J. J.; Anderson, S. F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Plotkin, R. M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Brandt, W. N.; Schneider, D. P. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Burnett, T. H. [Department of Physics, University of Washington, Seattle, WA 98195-1560 (United States); Myers, A. D., E-mail: jruan@astro.washington.edu [Department of Physics and Astronomy 3905, University of Wyoming, 1000 East University, Laramie, WY 82071 (United States)

    2014-12-10

    Blazars are classically divided into the BL Lacertae (BLL) and flat-spectrum radio quasar (FSRQ) subclasses, corresponding to radiatively inefficient and efficient accretion regimes, respectively, largely based on the equivalent width (EW) of their optical broad emission lines (BELs). However, EW-based classification criteria are not physically motivated, and a few blazars have previously transitioned' from one subclass to the other. We present the first systematic search for these transition blazars in a sample of 602 unique pairs of repeat spectra of 354 blazars in the Sloan Digital Sky Survey, finding six clear cases. These transition blazars have bolometric Eddington ratios of ∼0.3 and low-frequency synchrotron peaks, and are thus FSRQ-like. We show that the strong EW variability (up to an unprecedented factor of >60) is due to swamping of the BELs from variability in jet continuum emission, which is stronger in amplitude and shorter in timescale than typical blazars. Although these transition blazars appear to switch between FSRQ and BLL according to the phenomenologically based EW scheme, we show that they are most likely rare cases of FSRQs with radiatively efficient accretion flows and especially strongly beamed jets. These results have implications for the decrease of the apparent BLL population at high redshifts, and may lend credence to claims of a negative BLL redshift evolution.

  11. The transition to hospital consultant

    DEFF Research Database (Denmark)

    Westerman, Michiel; Teunissen, Pim W.; Jorgensen, Rasmus Lundhus

    2013-01-01

    Danish and Dutch new consultants' perceptions regarding the transition to consultant were compared to gain insight into this period, particularly the influence of contextual factors concerning the organisation of specialty training and health care therein. Preparation for medical and generic comp...... competencies, perceived intensity and burnout were compared. Additionally, effects of differences in working conditions and cultural dimensions were explored....

  12. "Mexico in Transition." Curriculum Units.

    Science.gov (United States)

    Oregon Univ., Eugene. Foreign Language Resource Center.

    These curriculum units were developed in a National Endowment for the Humanities 1994 summer seminar "Mexico in Transition." The 23 lessons are written in Spanish. Lessons are entitled: (1) "La Migracion Mexicana Vista a Traves del Cuento 'Paso del Norte' de Juan Rulfo" (Jose Jorge Armendariz); (2) "Los Grupos Indigenas de Mexico: Condiciones…

  13. Preterm Birth: Transition to Adulthood

    Science.gov (United States)

    Allen, Marilee C.; Cristofalo, Elizabeth; Kim, Christina

    2010-01-01

    Preterm birth is associated with greater difficulty with transitions from childhood to adolescence to adulthood. Adolescents and young adults born preterm have higher rates of cerebral palsy, intellectual disability, cognitive impairment, learning disability, executive dysfunction, attention deficit disorder, and social-emotional difficulties than…

  14. Malmo: A city in transition

    DEFF Research Database (Denmark)

    Anderson, Tessa Kate

    2014-01-01

    . From 1840 to the mid-1970s, Malmo’s growth continued to flourish. Like many Swedish cities, the manufacturing recession of the mid-1970s bought unemployment and population decline. Malmo transitioned from a manufacturing hub into a knowledge city with a strong focus on sustainable planning. Malmo has...

  15. $\\Delta$-N Electromagnetic Transition

    CERN Document Server

    Loan, M

    1999-01-01

    The EM ratio for a free Delta electromagnetic transition is discussed within the frame work of nonrelativistic approach. Such an approach gives a good account of data for a free Delta but is less important for an intrinsically relativistic nuclear many body problem.

  16. Detecting non-transiting exoplanets

    Science.gov (United States)

    Placek, Ben; Richards, Zachary; Knuth, Kevin H.

    2013-08-01

    Currently, the most popular way of detecting Extra-solar planets (exoplanets) is via the Transit Method. This method is limited only to planets with orbits such that we observe them transiting their host star. In this work in progress, we propose to identify non-transiting exoplanets in the data currently being collected by the Kepler Space Telescope by detecting orbital phase reflected light variations. Since such variations are due to light from the host star reflected by the planet, we expect this method to work best on closely orbitting large planets. Using the Metropolis-Hastings Monte Carlo and Nested Sampling algorithms, we will determine the presence or absence of nontransiting planets and estimate their orbital parameters such as, orbital inclination, semi-major axis, period, and eccentricity. Our estimates indicate that the development of this technique has the potential to double the number of detectable planets in the Kepler data sets. Here we demonstrate feasibility using portions of data from one of the first transiting planets detected by Kepler, HAT-P-7b.

  17. Electrical Conductivity in Transition Metals

    Science.gov (United States)

    Talbot, Christopher; Vickneson, Kishanda

    2013-01-01

    The aim of this "Science Note" is to describe how to test the electron-sea model to determine whether it accurately predicts relative electrical conductivity for first-row transition metals. In the electron-sea model, a metal crystal is viewed as a three-dimensional array of metal cations immersed in a sea of delocalised valence…

  18. Metal-to-nonmetal transitions

    CERN Document Server

    Hensel, Friedrich; Holst, Bastian

    2010-01-01

    This book is devoted to nonmetal-to-metal transitions. The original ideas of Mott for such a transition in solids have been adapted to describe a broad variety of phenomena in condensed matter physics (solids, liquids, and fluids), in plasma and cluster physics, as well as in nuclear physics (nuclear matter and quark-gluon systems). The book gives a comprehensive overview of theoretical methods and experimental results of the current research on the Mott effect for this wide spectrum of topics. The fundamental problem is the transition from localized to delocalized states which describes the nonmetal-to-metal transition in these diverse systems. Based on the ideas of Mott, Hubbard, Anderson as well as Landau and Zeldovich, internationally respected scientists present the scientific challenges and highlight the enormous progress which has been achieved over the last years. The level of description is aimed to specialists in these fields as well as to young scientists who will get an overview for their own work...

  19. Developmental transitions: So what's new?

    NARCIS (Netherlands)

    van der Maas, H.L.J.; Hopkins, B.

    1998-01-01

    Structural approaches to development, such as Piaget's stage theory, have proved to be problematic in dealing with developmental transitions. More promising in this respect are models of qualitative change that address macroscopical phase shifts in non-linear dynamicalsystems that arise from quantit

  20. Transiting Exoplanet Survey Satellite (TESS)

    Science.gov (United States)

    Ricker, G. R.; Clampin, M.; Latham, D. W.; Seager, S.; Vanderspek, R. K.; Villasenor, J. S.; Winn, J. N.

    2012-01-01

    The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey, TESS will monitor more than 500,000 stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances. No ground-based survey can achieve this feat. A large fraction of TESS target stars will be 30-100 times brighter than those observed by Kepler satellite, and therefore TESS . planets will be far easier to characterize with follow-up observations. TESS will make it possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars. TESS will provide prime targets for observation with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future. TESS data will be released with minimal delay (no proprietary period), inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the very nearest and brightest main-sequence stars hosting transiting exoplanets, thus providing future observers with the most favorable targets for detailed investigations.

  1. American Higher Education in Transition

    Science.gov (United States)

    Ehrenberg, Ronald G.

    2011-01-01

    American higher education is in transition and if there ever was a "golden age" for faculty, it probably is behind us. The best historical data on the composition of faculty is collected annually by the American Mathematical Society. Between 1967 and 2009, the share of full-time faculty with PhDs remained constant at about 90 percent at…

  2. COMPARATIVE HABITABILITY OF TRANSITING EXOPLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Rory; Meadows, Victoria S.; Evans, Nicole, E-mail: rory@astro.washington.edu [Astronomy Department, University of Washington, Box 951580, Seattle, WA 98195 (United States)

    2015-12-01

    Exoplanet habitability is traditionally assessed by comparing a planet’s semimajor axis to the location of its host star’s “habitable zone,” the shell around a star for which Earth-like planets can possess liquid surface water. The Kepler space telescope has discovered numerous planet candidates near the habitable zone, and many more are expected from missions such as K2, TESS, and PLATO. These candidates often require significant follow-up observations for validation, so prioritizing planets for habitability from transit data has become an important aspect of the search for life in the universe. We propose a method to compare transiting planets for their potential to support life based on transit data, stellar properties and previously reported limits on planetary emitted flux. For a planet in radiative equilibrium, the emitted flux increases with eccentricity, but decreases with albedo. As these parameters are often unconstrained, there is an “eccentricity-albedo degeneracy” for the habitability of transiting exoplanets. Our method mitigates this degeneracy, includes a penalty for large-radius planets, uses terrestrial mass–radius relationships, and, when available, constraints on eccentricity to compute a number we call the “habitability index for transiting exoplanets” that represents the relative probability that an exoplanet could support liquid surface water. We calculate it for Kepler objects of interest and find that planets that receive between 60% and 90% of the Earth’s incident radiation, assuming circular orbits, are most likely to be habitable. Finally, we make predictions for the upcoming TESS and James Webb Space Telescope missions.

  3. Comparative Habitability of Transiting Exoplanets

    Science.gov (United States)

    Barnes, Rory; Meadows, Victoria S.; Evans, Nicole

    2015-12-01

    Exoplanet habitability is traditionally assessed by comparing a planet’s semimajor axis to the location of its host star’s “habitable zone,” the shell around a star for which Earth-like planets can possess liquid surface water. The Kepler space telescope has discovered numerous planet candidates near the habitable zone, and many more are expected from missions such as K2, TESS, and PLATO. These candidates often require significant follow-up observations for validation, so prioritizing planets for habitability from transit data has become an important aspect of the search for life in the universe. We propose a method to compare transiting planets for their potential to support life based on transit data, stellar properties and previously reported limits on planetary emitted flux. For a planet in radiative equilibrium, the emitted flux increases with eccentricity, but decreases with albedo. As these parameters are often unconstrained, there is an “eccentricity-albedo degeneracy” for the habitability of transiting exoplanets. Our method mitigates this degeneracy, includes a penalty for large-radius planets, uses terrestrial mass-radius relationships, and, when available, constraints on eccentricity to compute a number we call the “habitability index for transiting exoplanets” that represents the relative probability that an exoplanet could support liquid surface water. We calculate it for Kepler objects of interest and find that planets that receive between 60% and 90% of the Earth’s incident radiation, assuming circular orbits, are most likely to be habitable. Finally, we make predictions for the upcoming TESS and James Webb Space Telescope missions.

  4. On P-transitive graphs and applications

    Directory of Open Access Journals (Sweden)

    Giacomo Lenzi

    2011-06-01

    Full Text Available We introduce a new class of graphs which we call P-transitive graphs, lying between transitive and 3-transitive graphs. First we show that the analogue of de Jongh-Sambin Theorem is false for wellfounded P-transitive graphs; then we show that the mu-calculus fixpoint hierarchy is infinite for P-transitive graphs. Both results contrast with the case of transitive graphs. We give also an undecidability result for an enriched mu-calculus on P-transitive graphs. Finally, we consider a polynomial time reduction from the model checking problem on arbitrary graphs to the model checking problem on P-transitive graphs. All these results carry over to 3-transitive graphs.

  5. Introduction: Transitions from Violence. Analysing the Effects of Transitional Justice

    Directory of Open Access Journals (Sweden)

    Susanne Buckley-Zistel

    2013-06-01

    Full Text Available Transitional justice refers to processes of dealing with the aftermath of violent conflicts and human rights abuses in order to provide for a peaceful future. It makes use of a number of instruments and mechanisms – including tribunals, truth commissions, memory work, and reparations – which aim at uncovering the truth about past crimes, putting past wrongs right, holding perpetrators accountable, vindicating the dignity of victim-survivors, and contributing to reconciliation. The objective of this focus section is to critically assess the potential of transitional justice, its achievements thus far, any conflicting goals, and the inherent or external obstacles that limit its influence and reach. Through empirical case studies from across the globe it paints a multi-faceted picture of the strengths and weaknesses of the approach.

  6. Standard tri-point transition function

    Institute of Scientific and Technical Information of China (English)

    XIE Yuquan

    2005-01-01

    It is usually difficult to express a family of tri-point transition function (TTF)by a transition matrix as Markov processes with one parameter. In this paper, we define three kinds of connection matrixes on the states of standard tri-point transition function (STTF) and study their essential character, give a constructive method on the constantvalue standard tri-point transition function and a general expression of the state-symmetric standard tri-point transition function by a sequence of the transition matrixes of special and simple Markov processes with one parameter.

  7. Composition of Transiting and Transiting-only super-Earths

    CERN Document Server

    Valencia, Diana

    2011-01-01

    The relatively recent detections of the first three transiting super-Earths mark the beginning of a subfield within exoplanets that is both fruitful and challenging. The first step into characterizing these objects is to infer their composition given the degenerate character of the problem. The calculations show that Kepler-10b has a composition between an Earth-like and a Mercury-like (enriched in iron) composition. In contrast, GJ 1214b is too large to be solid, and has to have a volatile envelope. Lastly, while three of the four reported mass estimates of CoRoT-7b allow for a rocky composition, one forbids it and can only be reconciled with significant amounts of water vapor. In addition to these three transiting low-mass planets, there are now more than one thousand Kepler planets with only measured radius. Even without a mass measurement ("transiting-only") it is still possible to place constraints on the amount of volatile content of the highly-irradiated planets, as their envelopes, if present, are fla...

  8. Geometric transitions and integrable systems

    Energy Technology Data Exchange (ETDEWEB)

    Diaconescu, D.-E. [New High Energy Theory Center, Rutgers University, 126 Frelinghuysen Road, Piscataway, NJ 08854 (United States)]. E-mail: duiliu@physics.rutgers.edu; Dijkgraaf, R. [Institute for Theoretical Physics and KdV Institute for Mathematics, University of Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam (Netherlands); Donagi, R. [Department of Mathematics, University of Pennsylvania, David Rittenhouse Laboratory, 209 South 33rd Street, Philadelphia, PA 19104-6395 (United States); Hofman, C. [The Weizmann Institute for Science, Department of Particle Physics, Herzl Street 2, 76100 Rehovot (Israel); Pantev, T. [Department of Mathematics, University of Pennsylvania, David Rittenhouse Laboratory, 209 South 33rd Street, Philadelphia, PA 19104-6395 (United States)

    2006-09-25

    We consider B-model large N duality for a new class of noncompact Calabi-Yau spaces modeled on the neighborhood of a ruled surface in a Calabi-Yau threefold. The closed string side of the transition is governed at genus zero by an A{sub 1} Hitchin integrable system on a genus g Riemann surface {sigma}. The open string side is described by a holomorphic Chern-Simons theory which reduces to a generalized matrix model in which the eigenvalues lie on the compact Riemann surface {sigma}. We show that the large N planar limit of the generalized matrix model is governed by the same A{sub 1} Hitchin system therefore proving genus zero large N duality for this class of transitions.

  9. Geometric transitions and integrable systems

    CERN Document Server

    Diaconescu, D E; Dijkgraaf, R; Hofman, C M; Pantev, T; Diaconescu, Duiliu-Emanuel; Donagi, Ron; Dijkgraaf, Robbert; Hofman, Christiaan; Pantev, Tony

    2005-01-01

    We consider {\\bf B}-model large $N$ duality for a new class of noncompact Calabi-Yau spaces modeled on the neighborhood of a ruled surface in a Calabi-Yau threefold. The closed string side of the transition is governed at genus zero by an $A_1$ Hitchin integrable system on a genus $g$ Riemann surface $\\Sigma$. The open string side is described by a holomorphic Chern-Simons theory which reduces to a generalized matrix model in which the eigenvalues lie on the compact Riemann surface $\\Sigma$. We show that the large $N$ planar limit of the generalized matrix model is governed by the same $A_1$ Hitchin system therefore proving genus zero large $N$ duality for this class of transitions.

  10. Geometric transitions and integrable systems

    Science.gov (United States)

    Diaconescu, D.-E.; Dijkgraaf, R.; Donagi, R.; Hofman, C.; Pantev, T.

    2006-09-01

    We consider B-model large N duality for a new class of noncompact Calabi-Yau spaces modeled on the neighborhood of a ruled surface in a Calabi-Yau threefold. The closed string side of the transition is governed at genus zero by an A Hitchin integrable system on a genus g Riemann surface Σ. The open string side is described by a holomorphic Chern-Simons theory which reduces to a generalized matrix model in which the eigenvalues lie on the compact Riemann surface Σ. We show that the large N planar limit of the generalized matrix model is governed by the same A Hitchin system therefore proving genus zero large N duality for this class of transitions.

  11. Appreciative inquiry and leadership transitions.

    Science.gov (United States)

    Keefe, Maureen R; Pesut, Daniel

    2004-01-01

    In times of accelerated change accompanied by leadership transitions, appreciative inquiry (AI) and sensemaking skills are necessary. AI is a philosophy, a model of change, and a set of tools and techniques that support discovery, dreaming, design, and creation of a vision that inspires people in an organization to move toward a collective destiny. Sensemaking involves sizing up a situation to create a framework for decision-making, creating a context for communication, linking with others, and focusing on what is and what could be. Sensemaking can be facilitated by applying appreciative leadership techniques. In this article, the story of the University of Utah College of Nursing's and the faculty's experience with an AI process illustrates the application of the AI leadership strategy to navigating organizational change and a leadership transition.

  12. Aging transition by random errors

    Science.gov (United States)

    Sun, Zhongkui; Ma, Ning; Xu, Wei

    2017-02-01

    In this paper, the effects of random errors on the oscillating behaviors have been studied theoretically and numerically in a prototypical coupled nonlinear oscillator. Two kinds of noises have been employed respectively to represent the measurement errors accompanied with the parameter specifying the distance from a Hopf bifurcation in the Stuart-Landau model. It has been demonstrated that when the random errors are uniform random noise, the change of the noise intensity can effectively increase the robustness of the system. While the random errors are normal random noise, the increasing of variance can also enhance the robustness of the system under certain conditions that the probability of aging transition occurs reaches a certain threshold. The opposite conclusion is obtained when the probability is less than the threshold. These findings provide an alternative candidate to control the critical value of aging transition in coupled oscillator system, which is composed of the active oscillators and inactive oscillators in practice.

  13. Sm Transition Probabilities and Abundances

    CERN Document Server

    Lawler, J E; Sneden, C; Cowan, J J

    2005-01-01

    Radiative lifetimes, accurate to +/- 5%, have been measured for 212 odd-parity levels of Sm II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier-transform spectrometry to determine transition probabilities for more than 900 lines of Sm II. This work is the largest-scale laboratory study to date of Sm II transition probabilities using modern methods. This improved data set has been used to determine a new solar photospheric Sm abundance, log epsilon = 1.00 +/- 0.03, from 26 lines. The spectra of three very metal-poor, neutron-capture-rich stars also have been analyzed, employing between 55 and 72 Sm II lines per star. The abundance ratios of Sm relative to other rare earth elements in these stars are in agreement, and are consistent with ratios expected from rapid neutron-capture nucleosynthesis (the r-process).

  14. Waste Socio-technological Transitions

    DEFF Research Database (Denmark)

    Zapata Campos, Maria José; Zapata, Patrik; Eriksson-Zetterquist, Ulla

    2014-01-01

    ) of making waste simply unbecome. This chapter explores the challenges faced by waste regime transitions based on the case of the historical evolution of household waste management in Sweden. The chapter first introduces transition studies’ multi-level framework in combination with the notion of lock......The transformation of packaging waste from a problem into a resource has had significant consequences for a more sustainable use of natural resources and even the reduction of potential C02 emissions and its contribution to the climate change. Material recycling leads to separated material being...... able to replace other production or construction materials. It also means that the consumption of the amount of virgin material decreases and saves energy. Despite the growing material recycling rates, the amount of waste per person, and packaging waste among others, continues to increase. High...

  15. Aging transition by random errors

    Science.gov (United States)

    Sun, Zhongkui; Ma, Ning; Xu, Wei

    2017-01-01

    In this paper, the effects of random errors on the oscillating behaviors have been studied theoretically and numerically in a prototypical coupled nonlinear oscillator. Two kinds of noises have been employed respectively to represent the measurement errors accompanied with the parameter specifying the distance from a Hopf bifurcation in the Stuart-Landau model. It has been demonstrated that when the random errors are uniform random noise, the change of the noise intensity can effectively increase the robustness of the system. While the random errors are normal random noise, the increasing of variance can also enhance the robustness of the system under certain conditions that the probability of aging transition occurs reaches a certain threshold. The opposite conclusion is obtained when the probability is less than the threshold. These findings provide an alternative candidate to control the critical value of aging transition in coupled oscillator system, which is composed of the active oscillators and inactive oscillators in practice. PMID:28198430

  16. Distress During the Menopause Transition

    Directory of Open Access Journals (Sweden)

    Marcianna Nosek

    2012-07-01

    Full Text Available In 2010, nearly 400 million women worldwide were of menopause age (45-54. Although many women transition through menopause with ease, some experience distress and a subsequent decrease in quality of life. The purpose of this qualitative study was to examine the experiences of distress in women during the menopause transition. A narrative analysis methodology was used maintaining participants’ complete narratives when possible. In-person interviews of 15 midlife women were digitally audio recorded and transcribed verbatim. Women shared narratives of distress related to menstrual changes, emotional instability, vaginal dryness, and decreased libido affected by their relationships with self, partners, work, and family. Some experiences were presented against a backdrop of the past and influenced by concerns for the future. Detailed stories illuminated the effect that distressful symptoms had on quality of life and captured how intricately woven symptoms were with the women’s interpersonal and social lives.

  17. Electroweak phase transition recent results

    CERN Document Server

    Csikor, Ferenc

    2000-01-01

    Recent results of four-dimensional (4d) lattice simulations on the finite temperature electroweak phase transition (EWPT) are discussed. The phase transition is of first order in the SU(2)-Higgs model below the end point Higgs mass 66.5$\\pm$1.4 GeV. For larger masses a rapid cross-over appears. This result completely agrees with the results of the dimensional reduction approach. Including the full Standard Model (SM) perturbatively the end point is at 72.1$\\pm$1.4 GeV. Combined with recent LEP Higgs mass lower bounds, this excludes any EWPT in the SM. A one-loop calculation of the static potential makes possible a precise comparison of the lattice and perturbative results. Recent 4d lattice studies of the Minimal Supersymmetric SM (MSSM) are also mentioned.

  18. Intermediaries in sustainable urban transitions

    DEFF Research Database (Denmark)

    Hoffmann, Birgitte; Agger, Annika

    The paper explores how local public authorities can support and facilitate projects, which promote sustainable transi-tion in urban neighbourhoods, by supporting local intermediaries. The role of intermediaries can be performed by a variety of actors such as public housing associations; NGO...... processes in sustainable urban management and the paper explores the development of communities of practise as a way to develop learning processes and new practises? The aim is to analyse approaches of involving citizens and how they contribute to the development of new actor configurations in urban social...... the development of new practises plays a part in multi level transitions. Empirically, the article is based on case studies from Denmark of local environmental centres, green guides etc. that have performed innovative forms of involving citizens in sustainable urban development. The empirical material...

  19. Major Transitions in Political Order

    CERN Document Server

    DeDeo, Simon

    2015-01-01

    We present three major transitions that occur on the way to the elaborate and diverse societies of the modern era. Our account links the worlds of social animals such as pigtail macaques and monk parakeets to examples from human history, including 18th Century London and the contemporary online phenomenon of Wikipedia. From the first awareness and use of group-level social facts to the emergence of norms and their self-assembly into normative bundles, each transition represents a new relationship between the individual and the group. At the center of this relationship is the use of coarse-grained information gained via lossy compression. The role of top-down causation in the origin of society parallels that conjectured to occur in the origin and evolution of life itself.

  20. Adolescents Transitioning to High School.

    Science.gov (United States)

    Williams, Susan G; Langhinrichsen-Rohling, Jennifer; Wornell, Cory; Finnegan, Heather

    2017-01-01

    Adolescents transitioning to high school may be at greater risk of depression and suicide if they are victims of bullying behavior. This study explored sex differences in bullying victimization (physical, verbal/social, and cyberbullying) and the impact on depressive symptoms and suicidal behaviors in ninth-grade students ( N = 233). Females reported significantly more verbal/social and cyberbullying than male students. There were no significant sex differences in physical bullying; male students who reported physical bullying victimization were more likely to experience depressive symptoms. Verbal/social bullying predicted depressive symptoms in males and females. Females who reported being victims of cyberbullying were more likely to report depressive symptoms, suicide ideation, and suicide attempts. Eighteen students reported suicide attempts, and each also experienced verbal/social bullying. School nurses are positioned to reach out to transitioning students, screen for mental health issues, provide a safe place to talk about bullying experiences, and promote positive mental health.

  1. Energy Transition to Renewables: Problems

    OpenAIRE

    2014-01-01

    What will come first ? non-acceptable global warming or extinction of oil reserves? Both processes can bring substantial costs to the mankind, but their order has important economic implications. The answer to this question will either lower oil price in the long run or will lead to its further rise. It is very important for Russian economy. From the global perspective, both dangers should be taken into account, and transition to renewable energies is the only remedy for both. However, the op...

  2. Women in Transition: A summary

    OpenAIRE

    UNICEF Innocenti Research Centre. MONEE project

    1999-01-01

    The 1999 Central and Eastern Europe and Commonwealth of Independent States Regional Monitoring Report focuses on the experiences of girls and women during the transition, highlighting their role in regional progress and the obstacles they face. The Report covers a broad range of issues, including women’s participation in the emerging market economy and democratic governments, female access to health and education, trends in family formation and violence against women and girls. The Report cal...

  3. Geometrical Aspects of Venus Transit

    CERN Document Server

    Bertuola, Alberto C; Magalhães, N S; Filho, Victo S

    2016-01-01

    We obtained two astronomical values, the Earth-Venus distance and Venus diameter, by means of a geometrical treatment of photos taken of Venus transit in June of 2012. Here we presented the static and translational modelsthat were elaborated taking into account the Earth and Venus orbital movements. An additional correction was also added by considering the Earth rotation movement. The results obtained were compared with the values of reference from literature, showing very good concordance.

  4. Nucleon Resonance Transition Form factors

    Energy Technology Data Exchange (ETDEWEB)

    Burkert, Volker D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Mokeev, Viktor I. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Aznauryan, Inna G. [Yerevan Physics Inst. (YerPhI) (Armenia)

    2016-08-01

    We discuss recent results from CLAS on electromagnetic resonance transition amplitudes and their dependence on the distance scale (Q2). From the comparison of these results with most advanced theoretical calculations within QCD-based approaches there is clear evidence that meson-baryon contributions are present and important at large distances, i.e. small Q2, and that quark core contributions dominate the short distance behavior.

  5. Evaluation of transit lines plan

    OpenAIRE

    Cenek, Juraj

    2012-01-01

    The plan of mass transport or transit lines is a vital part of an organisation of public transportation services. An optimisation of the plan can improve the service either by reducing the operational costs or by improving of service quality. Three subjects interact in the problem namely state or local administration, transport companies and citizens. The plan optimisation should find the best compromise to satisfy interests of all actors. A relevant criterion must be defined to find the b...

  6. Nuclear effects in atomic transitions

    OpenAIRE

    Pálffy, Adriana

    2011-01-01

    Atomic electrons are sensitive to the properties of the nucleus they are bound to, such as nuclear mass, charge distribution, spin, magnetization distribution, or even excited level scheme. These nuclear parameters are reflected in the atomic transition energies. A very precise determination of atomic spectra may thus reveal information about the nucleus, otherwise hardly accessible via nuclear physics experiments. This work reviews theoretical and experimental aspects of the nuclear effects ...

  7. Fast flux test facility, transition project plan

    Energy Technology Data Exchange (ETDEWEB)

    Guttenberg, S.

    1994-11-15

    The FFTF Transition Project Plan, Revision 1, provides changes and project baseline for the deactivation activities necessary to transition the FFTF to a radiologically and industrially safe shutdown condition.

  8. Transitional Justice, Culture and Society: Beyond Outreach

    Directory of Open Access Journals (Sweden)

    Elise Ketelaars

    2014-12-01

    Full Text Available This article reviews Transitional Justice, Culture and Society: Beyond Outreach, edited by Clara Ramírez-Barat, International Center for Transitional Justice, New York: Social Science Research Council, 2014 ISBN 978-0-911400-02-1

  9. Essays on employment and unemployment transitions

    NARCIS (Netherlands)

    Nagore Garcia, Amparo

    2015-01-01

    This thesis addresses relevant questions related to labour market transitions in Spain. Using administrative records data from Spanish Social Security and applying correlated competing risks models, the impact of the current recession on unemployment and employment transitions and gender differences

  10. Nuclear physics: Elusive transition spotted in thorium

    Science.gov (United States)

    Safronova, Marianna

    2016-05-01

    The highly precise atomic clocks used in science and technology are based on electronic transitions in atoms. The discovery of a nuclear transition in thorium-229 raises hopes of making nuclear clocks a reality. See Article p.47

  11. Transition curves for highway geometric design

    CERN Document Server

    Kobryń, Andrzej

    2017-01-01

    This book provides concise descriptions of the various solutions of transition curves, which can be used in geometric design of roads and highways. It presents mathematical methods and curvature functions for defining transition curves. .

  12. Atomic homodyne detection of weak atomic transitions.

    Science.gov (United States)

    Gunawardena, Mevan; Elliott, D S

    2007-01-26

    We have developed a two-color, two-pathway coherent control technique to detect and measure weak optical transitions in atoms by coherently beating the transition amplitude for the weak transition with that of a much stronger transition. We demonstrate the technique in atomic cesium, exciting the 6s(2)S(1/2) --> 8s(2)S(1/2) transition via a strong two-photon transition and a weak controllable Stark-induced transition. We discuss the enhancement in the signal-to-noise ratio for this measurement technique over that of direct detection of the weak transition rate, and project future refinements that may further improve its sensitivity and application to the measurement of other weak atomic interactions.

  13. Major transitions in information technology.

    Science.gov (United States)

    Valverde, Sergi

    2016-08-19

    When looking at the history of technology, we can see that all inventions are not of equal importance. Only a few technologies have the potential to start a new branching series (specifically, by increasing diversity), have a lasting impact in human life and ultimately became turning points. Technological transitions correspond to times and places in the past when a large number of novel artefact forms or behaviours appeared together or in rapid succession. Why does that happen? Is technological change continuous and gradual or does it occur in sudden leaps and bounds? The evolution of information technology (IT) allows for a quantitative and theoretical approach to technological transitions. The value of information systems experiences sudden changes (i) when we learn how to use this technology, (ii) when we accumulate a large amount of information, and (iii) when communities of practice create and exchange free information. The coexistence between gradual improvements and discontinuous technological change is a consequence of the asymmetric relationship between complexity and hardware and software. Using a cultural evolution approach, we suggest that sudden changes in the organization of ITs depend on the high costs of maintaining and transmitting reliable information.This article is part of the themed issue 'The major synthetic evolutionary transitions'.

  14. Saturn as a Transiting Exoplanet

    Science.gov (United States)

    Dalba, Paul A.; Muirhead, Philip S.; Fortney, Jonathan J.; Hedman, Matthew M.; Nicholson, Philip D.; Veyette, Mark J.

    2015-11-01

    Previous investigations of exoplanet atmospheres have not targeted those resembling the gas giant planets in our solar system. These types of exoplanets are too cold to be directly imaged or observed in emission, and their low transit probabilities and frequencies make characterization via transmission spectroscopy a challenging endeavor. However, studies of cold giant exoplanets would be highly valuable to our understanding of planet formation and migration and could place the gas giant members of our own solar system in a greater context. Here, we use solar occultations observed by the Visual and Infrared Mapping Spectrometer aboard the Cassini Spacecraft to extract the 1 to 5 μm transmission spectrum of Saturn, as if it were a transiting exoplanet. We detect absorption features from several molecules despite the presence of ammonia clouds. Self-consistent exoplanet atmosphere models show good agreement with Saturn's transmission spectrum but fail to reproduce the largest feature in the spectrum. We also find that atmospheric refraction determines the minimum altitude that could be probed during mid-transit of a Saturn-twin exoplanet around a Sun-like star. These results suggest that transmission spectroscopy of cold, long-period gaseous exoplanets should be possible with current and future observatories.

  15. The Transiting Exoplanet Survey Satellite

    CERN Document Server

    Ricker, George R; Vanderspek, Roland; Latham, David W; Bakos, Gaspar A; Bean, Jacob L; Berta-Thompson, Zachory K; Brown, Timothy M; Buchhave, Lars; Butler, Nathaniel R; Butler, R Paul; Chaplin, William J; Charbonneau, David; Christensen-Dalsgaard, Jorgen; Clampin, Mark; Deming, Drake; Doty, John; De Lee, Nathan; Dressing, Courtney; Dunham, E W; Endl, Michael; Fressin, Francois; Ge, Jian; Henning, Thomas; Holman, Matthew J; Howard, Andrew W; Ida, Shigeru; Jenkins, Jon; Jernigan, Garrett; Johnson, John Asher; Kaltenegger, Lisa; Kawai, Nobuyuki; Kjeldsen, Hans; Laughlin, Gregory; Levine, Alan M; Lin, Douglas; Lissauer, Jack J; MacQueen, Phillip; Marcy, Geoffrey; McCullough, P R; Morton, Timothy D; Narita, Norio; Paegert, Martin; Palle, Enric; Pepe, Francesco; Pepper, Joshua; Quirrenbach, Andreas; Rinehart, S A; Sasselov, Dimitar; Sato, Bun'ei; Seager, Sara; Sozzetti, Alessandro; Stassun, Keivan G; Sullivan, Peter; Szentgyorgyi, Andrew; Torres, Guillermo; Udry, Stephane; Villasenor, Joel

    2014-01-01

    The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its two-year mission, TESS will employ four wide-field optical CCD cameras to monitor at least 200,000 main-sequence dwarf stars with I<13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from one month to one year, depending mainly on the star's ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10-100 times brighter than those surveyed by the pioneering Kepler missio...

  16. Marital transitions. A child's perspective.

    Science.gov (United States)

    Hetherington, E M; Stanley-Hagan, M; Anderson, E R

    1989-02-01

    Despite a recent leveling off of the divorce rate, almost half of the children born in the last decade will experience the divorce of their parents, and most of these children will also experience the remarriage of their parents. Most children initially experience their parents' marital rearrangements as stressful; however, children's responses to their parents marital transitions are diverse. Whereas some exhibit remarkable resiliency and in the long term may actually be enhanced by coping with these transitions, others suffer sustained developmental delays or disruptions. Others appear to adapt well in the early stages of family reorganizations but show delayed effects that emerge at a later time, especially in adolescence. The long-term effects are related more to the child's developmental status, sex, and temperament; the qualities of the home and parenting environments; and to the resources and support systems available to the parents and child than they are to divorce or remarriage per se. In recent years, researchers have begun to move away from the view that single-parent and remarried families are atypical or pathogenic families and are focusing on the diversity of children's responses and to the factors that facilitate or disrupt the development and adjustment of children experiencing their parents' marital transitions.

  17. Search For Planetary Transits in Auriga

    Science.gov (United States)

    Mandushev, G. I.; Dunham, E. W.; Latham, D. W.; Everett, M.

    2007-07-01

    We report the results of an extensive, three-year search for planetary transits in a Milky Way field in the constellation of Auriga. More than 60 objects with transit-like events in their light curves were detected. Photometric and spectroscopic follow-up observations were carried out on the most promising transit candidates. Despite the large number of candidates, so far none of them has been found to be a transiting planet.

  18. Transitions from preschool to primary school

    DEFF Research Database (Denmark)

    Broström, Stig; Einarsdottir, Johanna; Vrinioti, Kalliope

    2010-01-01

      The article deals with transition from preschool to primary school. Starting with a historical overview presenting Fröbel's transition understanding from 1852 over European politics in the 1960s and 1970s, recommendations by the Councils of Europe from the 1990s and ending with OECD's actual po...... and in continuation of this a description of a number of so-called transition activities are described in order to ease children's transition to school....

  19. How Theories of Organization Inform Transition Studies

    OpenAIRE

    van Mossel, Allard; van Rijnsoever, Frank; Hekkert, Marko

    2014-01-01

    In historical socio-technical transitions, organizations functioned as the principal drivers of transitions, invented the defining innovations, and created the cognitive and normative rules that led industries to embrace the innovation and associated behavior. Yet, despite their importance, the roles of organizations in transitions and, in particular, the processes that guide and coordinate their behavior, remain under-conceptualized in some transition frameworks, including the Multi-Level Pe...

  20. Lost in Transition? Student Food Consumption

    Science.gov (United States)

    Blichfeldt, Bodil Stilling; Gram, Malene

    2013-01-01

    Findings from transition studies as well as studies of student food show that the transition from living at home to independent living influences student food consumption and that food consumption might be problematic during this period. Furthermore, both students' enactment of being in transition and the food habits and practices they bring with…

  1. Transition problems and play as transitory activity

    DEFF Research Database (Denmark)

    Broström, Stig

    2005-01-01

    Because too many children experience the transition to school as a culture shock, during the past decade teachers have implemented so-called transition activities in order to bridge the gap betwen pre-school and schoo. However, transition to school also calls for a development of higher mental fu...

  2. Modal Transition Systems with Weight Intervals

    DEFF Research Database (Denmark)

    Juhl, Line; Larsen, Kim Guldstrand; Srba, Jiri

    2012-01-01

    We propose weighted modal transition systems, an extension to the well-studied specification formalism of modal transition systems that allows to express both required and optional behaviours of their intended implementations. In our extension we decorate each transition with a weight interval th...

  3. PERCOLATION TRANSITION IN ELECTRORHEOLOGICAL FLUIDS

    Institute of Scientific and Technical Information of China (English)

    HAO Tian; CHEN Yihong; XU Zhengmiao; XU Yuanze; HUANG Yun

    1994-01-01

    The electric conductivity, dynamic modulus and yield stress of the developed electrorheological fluid (ERF) are measured at different volume fraction and different electric field strength using a modified Rheosetrics Mechanical Spectrometer (Model 605). The percolation theory is introduced to explain electrorheological effect and found that the ERF's have the similar percolated network structure as that of other ordinary suspensions with a critical volume fraction value independent of electric field strength. A master curve of dimensionless modulus against dimensionless volume fraction is obtained. which shows that the essence of ER phenomenon actually is one kind of the second ofder phase transition.

  4. Gibbs measures and phase transitions

    CERN Document Server

    Georgii, Hans-Otto

    2011-01-01

    From a review of the first edition: ""This book […] covers in depth a broad range of topics in the mathematical theory of phase transition in statistical mechanics. […] It is in fact one of the author's stated aims that this comprehensive monograph should serve both as an introductory text and as a reference for the expert."" (F. Papangelou, Zentralblatt MATH) The second edition has been extended by a new section on large deviations and some comments on the more recent developments in the area.

  5. Monopole transitions in hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sujkowski, Z. [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

    1994-12-31

    Monopole transitions can be a signature of shape changing in a hot, pulsating nucleus (the low energy E0 mode) and/or a measure of the compressibility of finite nuclei (GMR, the breathing mode). Experimental information pertaining to GMR is reviewed. Recipes for deducing the incompressibility modules for infinite nuclear matter from data on GMR are discussed. Astrophysical implications are outlined. The first attempts at locating the GMR strength in moderately hot nuclei are described. Prospects for improving the experimental techniques to make an observation of this strength in selected nuclei unambiguous are discussed. (author). 46 refs, 8 figs.

  6. The Amazon basin in transition.

    Science.gov (United States)

    Davidson, Eric A; de Araújo, Alessandro C; Artaxo, Paulo; Balch, Jennifer K; Brown, I Foster; C Bustamante, Mercedes M; Coe, Michael T; DeFries, Ruth S; Keller, Michael; Longo, Marcos; Munger, J William; Schroeder, Wilfrid; Soares-Filho, Britaldo S; Souza, Carlos M; Wofsy, Steven C

    2012-01-18

    Agricultural expansion and climate variability have become important agents of disturbance in the Amazon basin. Recent studies have demonstrated considerable resilience of Amazonian forests to moderate annual drought, but they also show that interactions between deforestation, fire and drought potentially lead to losses of carbon storage and changes in regional precipitation patterns and river discharge. Although the basin-wide impacts of land use and drought may not yet surpass the magnitude of natural variability of hydrologic and biogeochemical cycles, there are some signs of a transition to a disturbance-dominated regime. These signs include changing energy and water cycles in the southern and eastern portions of the Amazon basin.

  7. Phase Transition in Tensor Models

    CERN Document Server

    Delepouve, Thibault

    2015-01-01

    Generalizing matrix models, tensor models generate dynamical triangulations in any dimension and support a $1/N$ expansion. Using the intermediate field representation we explicitly rewrite a quartic tensor model as a field theory for a fluctuation field around a vacuum state corresponding to the resummation of the entire leading order in $1/N$ (a resummation of the melonic family). We then prove that the critical regime in which the continuum limit in the sense of dynamical triangulations is reached is precisely a phase transition in the field theory sense for the fluctuation field.

  8. Trust and Traditions in Transitions

    DEFF Research Database (Denmark)

    McQuaid, Sara Dybris

    and the state and more recently, trust in the peace process. As the contest over meaning is always determined by the context of articulation, this paper examines the role of parades in the current ‘post-conflict’ phase of the peace process. Using theories of cultural and collective memory (Assman 2011, Olick...... recesses of memory in the current transition. And b) that patterns of ‘competitive commemoration’ in parades should be understood in relation to the increasing dissonance between vernacular languages of conflict and the official post-conflict discourses in Northern Ireland....

  9. Phase transitions in operational risk.

    Science.gov (United States)

    Anand, Kartik; Kühn, Reimer

    2007-01-01

    In this paper we explore the functional correlation approach to operational risk. We consider networks with heterogeneous a priori conditional and unconditional failure probability. In the limit of sparse connectivity, self-consistent expressions for the dynamical evolution of order parameters are obtained. Under equilibrium conditions, expressions for the stationary states are also obtained. Consequences of the analytical theory developed are analyzed using phase diagrams. We find coexistence of operational and nonoperational phases, much as in liquid-gas systems. Such systems are susceptible to discontinuous phase transitions from the operational to nonoperational phase via catastrophic breakdown. We find this feature to be robust against variation of the microscopic modeling assumptions.

  10. Phase transitions and critical phenomena

    CERN Document Server

    Domb, Cyril

    2000-01-01

    The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. No longer an area of specialist interest, it has acquired a central focus in condensed matter studies. The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable information on important recent developments.The two review articles in this volume complement each other in a remarkable way. Both deal with what m

  11. Light scattering near phase transitions

    CERN Document Server

    Cummins, HZ

    1983-01-01

    Since the development of the laser in the early 1960's, light scattering has played an increasingly crucial role in the investigation of many types of phase transitions and the published work in this field is now widely dispersed in a large number of books and journals.A comprehensive overview of contemporary theoretical and experimental research in this field is presented here. The reviews are written by authors who have actively contributed to the developments that have taken place in both Eastern and Western countries.

  12. Heterostructures of transition metal dichalcogenides

    KAUST Repository

    Amin, Bin

    2015-08-24

    The structural, electronic, optical, and photocatalytic properties of out-of-plane and in-plane heterostructures of transition metal dichalcogenides are investigated by (hybrid) first principles calculations. The out-of-plane heterostructures are found to be indirect band gap semiconductors with type-II band alignment. Direct band gaps can be achieved by moderate tensile strain in specific cases. The excitonic peaks show blueshifts as compared to the parent monolayer systems, whereas redshifts occur when the chalcogen atoms are exchanged along the series S-Se-Te. Strong absorption from infrared to visible light as well as excellent photocatalytic properties can be achieved.

  13. Chiral transition with magnetic fields

    CERN Document Server

    Ayala, Alejandro; Mizher, Ana Julia; Rojas, Juan Cristobal; Villavicencio, Cristian

    2014-01-01

    We study the nature of the chiral transition for an effective theory with spontaneous breaking of symmetry, where charged bosons and fermions are subject to the effects of a constant external magnetic field. The problem is studied in terms of the relative intensity of the magnetic field with respect to the mass and the temperature. When the former is the smallest of the scales, we present a suitable method to obtain magnetic and thermal corrections up to ring order at high temperature. By these means, we solve the problem of the instability in the boson sector for these theories, where the squared masses, taken as functions of the order parameter, can vanish and even become negative. The solution is found by considering the screening properties of the plasma, encoded in the resummation of the ring diagrams at high temperature. We also study the case where the magnetic field is the intermediate of the three scales and explore the nature of the chiral transition as we vary the field strength, the coupling const...

  14. Nutrition transition and food sustainability.

    Science.gov (United States)

    Belahsen, Rekia

    2014-08-01

    The aim of the present paper is to review nutrition transition (NT) ongoing in low and middle income countries and the associated dietary changes. NT is accompanied by demographic and epidemiological transition associated with economic development and urbanisation. In these countries, while the problems of hunger and undernourishment persist, there is an escalation of diet-related non-communicable diseases; making them face both problems of malnutrition, under and overnutrition. Indeed, in addition to protein energy malnutrition underweight and micronutrient deficiencies affect a high proportion of children and women. Conversely, changes in dietary habits and physical activity patterns have led to emergence of chronic diseases such as obesity, diabetes, hypertension, stroke, hyperlipidaemia, CHD and cancer. One possible explanation of weight gain and its associated health consequences is the trend of the consumption of already prepared meals and the restaurants that are in continuous development leading to high consumption of foods rich in sugar and fat. The health problems associated with NT have not spared populations in the Mediterranean area where the type of diet is reported to be healthy and to protect against cardiovascular risks. This is seen in North Africa that belongs also to the Mediterranean basin, where the nutritional situation raises the problem of traditional foods sustainability. Accurate nutritional policy and education are needed to redress the effects of malnutrition related to NT on health.

  15. Hf Transition Probabilities and Abundances

    CERN Document Server

    Lawler, J E; Labby, Z E; Sneden, C; Cowan, J J; Ivans, I I

    2006-01-01

    Radiative lifetimes from laser-induced fluorescence measurements, accurate to about +/- 5 percent, are reported for 41 odd-parity levels of Hf II. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 150 lines of Hf II. Approximately half of these new transition probabilities overlap with recent independent measurements using a similar approach. The two sets of measurements are found to be in good agreement for measurements in common. Our new laboratory data are applied to refine the hafnium photospheric solar abundance and to determine hafnium abundances in 10 metal-poor giant stars with enhanced r-process abundances. For the Sun we derive log epsilon (Hf) = 0.88 +/- 0.08 from four lines; the uncertainty is dominated by the weakness of the lines and their blending by other spectral features. Within the uncertainties of our analysis, the r-process-rich stars possess constant Hf/La and Hf/Eu abundance ratios, log epsilon (Hf...

  16. Gd Transition Probabilities and Abundances

    CERN Document Server

    Den Hartog, E A; Sneden, C; Cowan, J J

    2006-01-01

    Radiative lifetimes, accurate to +/- 5%, have been measured for 49 even-parity and 14 odd-parity levels of Gd II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 611 lines of Gd II. This work is the largest-scale laboratory study to date of Gd II transition probabilities and the first using a high performance Fourier transform spectrometer. This improved data set has been used to determine a new solar photospheric Gd abundance, log epsilon = 1.11 +/- 0.03. Revised Gd abundances have also been derived for the r-process-rich metal-poor giant stars CS 22892-052, BD+17 3248, and HD 115444. The resulting Gd/Eu abundance ratios are in very good agreement with the solar-system r-process ratio. We have employed the increasingly accurate stellar abundance determinations, resulting in large part from the more precise laboratory atomic data, to predict directly the Solar System r-process elemental...

  17. Dynamic transition in supercritical iron.

    Science.gov (United States)

    Fomin, Yu D; Ryzhov, V N; Tsiok, E N; Brazhkin, V V; Trachenko, K

    2014-11-26

    Recent advance in understanding the supercritical state posits the existence of a new line above the critical point separating two physically distinct states of matter: rigid liquid and non-rigid gas-like fluid. The location of this line, the Frenkel line, remains unknown for important real systems. Here, we map the Frenkel line on the phase diagram of supercritical iron using molecular dynamics simulations. On the basis of our data, we propose a general recipe to locate the Frenkel line for any system, the recipe that importantly does not involve system-specific detailed calculations and relies on the knowledge of the melting line only. We further discuss the relationship between the Frenkel line and the metal-insulator transition in supercritical liquid metals. Our results enable predicting the state of supercritical iron in several conditions of interest. In particular, we predict that liquid iron in the Jupiter core is in the "rigid liquid" state and is highly conducting. We finally analyse the evolution of iron conductivity in the core of smaller planets such as Earth and Venus as well as exoplanets: as planets cool off, the supercritical core undergoes the transition to the rigid-liquid conducting state at the Frenkel line.

  18. Securing Power during the Transition

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    Electricity security has been a priority of energy policy for decades due to the dependence of modern society on ongoing supply of electricity. Only a few years ago there was confidence that liberalised electricity markets in IEA member countries could deliver sufficient and timely generation investments needed to ensure security of supply. However, policies to decarbonise electricity systems have served to magnify investment risk and uncertainty. At the same time as renewable support schemes have proven effective in facilitating deployment of wind and solar photovoltaics, they also introduce new challenges to design a stable regulatory framework and well-functioning markets. Securing Power during the Transition, a report in the Electricity Security Action Plan series, assesses the threats and identifies options for competitive electricity markets embarking on the transition towards generating electricity from low-carbon sources . The analysis covers the impact of the global economic and financial situation, energy policy context and the implications for electricity market design. Its objective is to identify opportunities to improve regulatory and market designs to create a framework for timely and adequate investment, with a particular focus on conventional power plants.

  19. TRANSITION IN TERMS OF GLOBALISATION

    Directory of Open Access Journals (Sweden)

    Miroslav Milutinović

    2014-10-01

    Full Text Available One of the essential constituents of the term transition, in Serbia as well as in other postsocialistic countries, refers to the transition from one development concept onto another one (extensive and mobilising, which is completely different (market-based and innovation-oriented. Market behaviour rules have changed to a great extent, as well as the increasingly present innovations in the field of technology, and introduced certain innovations in business orientation of companies. The struggle for market share is becoming more aggressive and dynamic enabling the survival of exclusively those companies which have implanted high flexibility and innovation levels into their business ambience. Globalisation is inherent in capitalism, it is its constituent logic. In future, new rules will have to be brought which would allow of the managment function to be performed within the complete business policy mutually agreed upon betwen the representatives of the capital owner and those of the personell. These regulations are necessary for long-term efficiency and profitability of private sector, as well as for the final success of economy.

  20. Photochemistry of Transition Metal Hydrides.

    Science.gov (United States)

    Perutz, Robin N; Procacci, Barbara

    2016-08-10

    Photochemical reactivity associated with metal-hydrogen bonds is widespread among metal hydride complexes and has played a critical part in opening up C-H bond activation. It has been exploited to design different types of photocatalytic reactions and to obtain NMR spectra of dilute solutions with a single pulse of an NMR spectrometer. Because photolysis can be performed on fast time scales and at low temperature, metal-hydride photochemistry has enabled determination of the molecular structure and rates of reaction of highly reactive intermediates. We identify five characteristic photoprocesses of metal monohydride complexes associated with the M-H bond, of which the most widespread are M-H homolysis and R-H reductive elimination. For metal dihydride complexes, the dominant photoprocess is reductive elimination of H2. Dihydrogen complexes typically lose H2 photochemically. The majority of photochemical reactions are likely to be dissociative, but hydride complexes may be designed with equilibrated excited states that undergo different photochemical reactions, including proton transfer or hydride transfer. The photochemical mechanisms of a few reactions have been analyzed by computational methods, including quantum dynamics. A section on specialist methods (time-resolved spectroscopy, matrix isolation, NMR, and computational methods) and a survey of transition metal hydride photochemistry organized by transition metal group complete the Review.

  1. THE QUASIPERIODIC AUTOMATED TRANSIT SEARCH ALGORITHM

    Energy Technology Data Exchange (ETDEWEB)

    Carter, Joshua A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Agol, Eric [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States)

    2013-03-10

    We present a new algorithm for detecting transiting extrasolar planets in time-series photometry. The Quasiperiodic Automated Transit Search (QATS) algorithm relaxes the usual assumption of strictly periodic transits by permitting a variable, but bounded, interval between successive transits. We show that this method is capable of detecting transiting planets with significant transit timing variations without any loss of significance-{sup s}mearing{sup -}as would be incurred with traditional algorithms; however, this is at the cost of a slightly increased stochastic background. The approximate times of transit are standard products of the QATS search. Despite the increased flexibility, we show that QATS has a run-time complexity that is comparable to traditional search codes and is comparably easy to implement. QATS is applicable to data having a nearly uninterrupted, uniform cadence and is therefore well suited to the modern class of space-based transit searches (e.g., Kepler, CoRoT). Applications of QATS include transiting planets in dynamically active multi-planet systems and transiting planets in stellar binary systems.

  2. Research on Methods of Processing Transit IC Card Information and Constructing Transit OD Matrix

    Science.gov (United States)

    Han, Xiuhua; Li, Jin; Peng, Han

    Transit OD matrix is of vital importance when planning urban transit system. Traditional transit OD matrix constructing method needs a large range of spot check survey. It is expensive and needs long cycle time to process information. Recently transit IC card charging systems have been widely applied in big cities. Being processed reasonably, transit passenger information stored in IC card database can turn into information resource. It will reduce survey cost a lot. The concept of transit trip chain is put forward in this paper. According to the characteristics of closed transit trip chain, it discusses how to process IC card information and construct transit OD matrix. It also points out that urban transit information platform and data warehouse should be constructed, and how to integrate IC card information.

  3. Hydrothermal processes in mylonitic rocks at the NW edge of the Grong culmination, central Norway

    NARCIS (Netherlands)

    Stel, H.

    1984-01-01

    The cataclasite and mylonites, and the brittle/ductile deformation processes that produced them, were studied in relation to the regional geology at exposures along the northern rim of the Grong culmination, a transverse basement antiform in the Scandinavian Caledonides.

  4. The Transiting System GJ1214: High-Precision Defocused Transit Observations and a Search for Evidence of Transit Timing Variation

    DEFF Research Database (Denmark)

    Harpsøe, Kennet Bomann West; Hardis, S.; Hinse, T. C.;

    2012-01-01

    Aims: We present 11 high-precision photometric transit observations of the transiting super-Earth planet GJ1214b. Combining these data with observations from other authors, we investigate the ephemeris for possible signs of transit timing variations (TTVs) using a Bayesian approach. Methods......: The observations are used to determine the photometric parameters and the physical properties of the GJ1214 system. Our results are in good agreement with published values. Individual times of mid-transit are measured with uncertainties as low as 10s, allowing us to reduce the uncertainty in the orbital period...

  5. Edge-Transitive Lexicographic and Cartesian Products

    Directory of Open Access Journals (Sweden)

    Imrich Wilfried

    2016-11-01

    Full Text Available In this note connected, edge-transitive lexicographic and Cartesian products are characterized. For the lexicographic product G ◦ H of a connected graph G that is not complete by a graph H, we show that it is edge-transitive if and only if G is edge-transitive and H is edgeless. If the first factor of G ∘ H is non-trivial and complete, then G ∘ H is edge-transitive if and only if H is the lexicographic product of a complete graph by an edgeless graph. This fixes an error of Li, Wang, Xu, and Zhao [11]. For the Cartesian product it is shown that every connected Cartesian product of at least two non-trivial factors is edge-transitive if and only if it is the Cartesian power of a connected, edge- and vertex-transitive graph.

  6. On artificial transits feasibility and SETI

    CERN Document Server

    Arnold, L

    2005-01-01

    It is known that the shape of a planet (oblateness, rings, etc.) slightly modifies the shape of the transit light curve. The forthcoming space missions (Corot, Kepler), able to detect the transit of Earth-like planets, could a fortiori also detect the transit of artificial planet-size objects if their shape is significantly different from a natural (planetary) object. Multiple artificial objects would also produce transit light curves easily recognizable from natural transits. Artificial transits, especially of multiple objects, could be used for the transmission of clear attention-getting signals, with a sky coverage (efficiency) comparable to that of the laser pulse method. Although out of reach of current human technologies, the building of an Earth-size 1-micron thick mask would require energy and bulk material amounts already managed on Earth today. The migration of the mask toward an inner orbit and its protection against asteroids or meteoroids are also briefly discussed.

  7. Transits Probabilities Around Hypervelocity and Runaway Stars

    CERN Document Server

    Fragione, Giacomo

    2016-01-01

    In the blooming field of exoplanetary science, NASA's Kepler Space Telescope has revolutionized our understanding of exoplanets. Kepler's very precise and long-duration photometry is ideal for detecting planetary transits around Sun-like stars. The forthcoming Transiting Exoplanet Survey Satellite (TESS) is expected to continue Kepler's legacy. In this paper, we explore the possibility of detecting planetary transits around hypervelocity and runaway stars, which should host a very compact system as consequence of their turbulent origin. We find that the probability of a multi-planetary transit is $10^{-3}\\lesssim P\\lesssim 10^{-1}$. We therefore need to observe $\\sim 10-1000$ high-velocity stars to spot a transit. We predict that the European Gaia satellite, along with TESS, could spot such transits.

  8. Transition probability spaces in loop quantum gravity

    CERN Document Server

    Guo, Xiao-Kan

    2016-01-01

    We study the (generalized) transition probability spaces, in the sense of Mielnik and Cantoni, for spacetime quantum states in loop quantum gravity. First, we show that loop quantum gravity admits the structures of transition probability spaces. This is achieved by first checking such structures in covariant quantum mechanics, and then passing to spin foam models via the general boundary formulation. The transition probability space thus defined gives a simple way to reconstruct the Hilbert space of the canonical theory and the relevant quantum logical structure. Second, we show that the transition probability space and in particular the spin foam model are 2-categories. Then we discuss how to realize property transitions and causality in this categorical context in connection with presheaves on quantaloids and respectively causal categories. We conclude that transition probability spaces provide us with an alternative framework to understand various foundational questions of loop quantum gravity.

  9. Measuring stellar granulation during planet transits

    CERN Document Server

    Chiavassa, A; Selsis, F; Leconte, J; Von Paris, P; Bordé, P; Magic, Z; Collet, R; Asplund, M

    2016-01-01

    Stellar activity and convection-related surface structures might cause bias in planet detection and characterization that use these transits. Surface convection simulations help to quantify the granulation signal. We used realistic three-dimensional radiative hydrodynamical simulations from the Stagger grid and synthetic images computed with the radiative transfer code Optim3D to model the transits of three prototype planets: a hot Jupiter, a hot Neptune, and a terrestrial planet. We computed intensity maps from RHD simulations of the Sun and a K-dwarf star at different wavelength bands from optical to far-infrared. We modeled the transit using synthetic stellar-disk images and emulated the temporal variation of the granulation intensity. We identified two types of granulation noise that act simultaneously during the planet transit: (i) the intrinsic change in the granulation pattern with timescales smaller than the usual planet transit, and (ii) the fact that the transiting planet occults isolated regions of...

  10. Transition from Poisson to circular unitary ensemble

    Indian Academy of Sciences (India)

    Vinayak; Akhilesh Pandey

    2009-09-01

    Transitions to universality classes of random matrix ensembles have been useful in the study of weakly-broken symmetries in quantum chaotic systems. Transitions involving Poisson as the initial ensemble have been particularly interesting. The exact two-point correlation function was derived by one of the present authors for the Poisson to circular unitary ensemble (CUE) transition with uniform initial density. This is given in terms of a rescaled symmetry breaking parameter Λ. The same result was obtained for Poisson to Gaussian unitary ensemble (GUE) transition by Kunz and Shapiro, using the contour-integral method of Brezin and Hikami. We show that their method is applicable to Poisson to CUE transition with arbitrary initial density. Their method is also applicable to the more general ℓ CUE to CUE transition where CUE refers to the superposition of ℓ independent CUE spectra in arbitrary ratio.

  11. Reflections on the Chilean Transition

    Directory of Open Access Journals (Sweden)

    Antonia SANTOS PÉREZ

    2016-05-01

    Full Text Available Chile has historically excelled in Latin America for its political stability and its institutional strength, which did not prevent it from living under an authoritarian regime (1973-1988. The political transition was a consequence of a fast political pact between the military and a strong political class that led to a limited democracy because of the origin and content of the Constitution, partially overcome by the constitutional reform of 2005. However, the slow development of the Chilean democratic process is due to both the institutional framework and the behavior of the political actors who have favored political stability based on consensus before the plurality of competition and the political debate for the sake of democratic quality.

  12. Transition to turbulence in ferrofluids

    CERN Document Server

    Altmeyer, Sebastian; Lai, Ying-Cheng

    2015-01-01

    It is known that in classical fluids turbulence typically occurs at high Reynolds numbers. But can turbulence occur at low Reynolds numbers? Here we investigate the transition to turbulence in the classic Taylor-Couette system in which the rotating fluids are manufactured ferrofluids with magnetized nanoparticles embedded in liquid carriers. We find that, in the presence of a magnetic field turbulence can occur at Reynolds numbers that are at least one order of magnitude smaller than those in conventional fluids. This is established by extensive computational ferrohydrodynamics through a detailed bifurcation analysis and characterization of behaviors of physical quantities such as the energy, the wave number, and the angular momentum through the bifurcations. A striking finding is that, as the magnetic field is increased, the onset of turbulence can be determined accurately and reliably. Our results imply that experimental investigation of turbulence can be greatly facilitated by using ferrofluids, opening up...

  13. Transition delay using control theory.

    Science.gov (United States)

    Bagheri, S; Henningson, D S

    2011-04-13

    This review gives an account of recent research efforts to use feedback control for the delay of laminar-turbulent transition in wall-bounded shear flows. The emphasis is on reducing the growth of small-amplitude disturbances in the boundary layer using numerical simulations and a linear control approach. Starting with the application of classical control theory to two-dimensional perturbations developing in spatially invariant flows, flow control based on control theory has progressed towards more realistic three-dimensional, spatially inhomogeneous flow configurations with localized sensing/actuation. The development of low-dimensional models of the Navier-Stokes equations has played a key role in this progress. Moreover, shortcomings and future challenges, as well as recent experimental advances in this multi-disciplinary field, are discussed.

  14. Ghana's cocoa frontier in transition

    DEFF Research Database (Denmark)

    Knudsen, Michael Helt; Agergaard, Jytte

    2015-01-01

    Since the first commercial planting of cocoa in Ghana more than a century ago, the production of cocoa has been a key factor in the redistribution of migrants and has played a pivotal role in the development of both sending and receiving communities. This process has been acknowledged...... in the literature for decades. However, how migration flows have changed in response to changing livelihoods dynamics of the frontier and how this has impacted on the development of the frontier has only attracted limited attention. Based on a study of immigration to Ghana's current cocoa frontier in the Western...... Region, this article aims to examine how immigration and frontier dynamics in the Western region are contributing to livelihood transitions and small town development, and how this process is gradually becoming delinked from the production of cocoa. The article focuses on how migration dynamics interlink...

  15. QUEUEING NETWORKS WITH INSTANTANEOUSSEQUENTIAL TRANSITIONS

    Institute of Scientific and Technical Information of China (English)

    Chao Xiuli

    2001-01-01

    We study queueing networks with instantaneous transitions of sequential batch departures and sequential batch arrivals. Unlike most of the existing models, this network is shown not to have a product form solution. An "extra arrival condition” is introduced under which the network is shown to possess a product form stationary distribution. Furthermore, the product form solution serves as a stochastic upper bound for the original network without the extra arrival process. The results include many queueing network models reported in the literature, e.g. the assembly transfer networks recently introduced by Miyazawa and Taylor, as special cases. We show that the network with the extra arrival process is "structurally reversible” in the sense that its reversed process has the same network structure. Local balances for this network are presented and discussed.

  16. Altitude transitions in energy climbs

    Science.gov (United States)

    Weston, A. R.; Cliff, E. M.; Kelley, H. J.

    1982-01-01

    The aircraft energy-climb trajectory for configurations with a sharp transonic drag rise is well known to possess two branches in the altitude/Mach-number plane. Transition in altitude between the two branches occurs instantaneously, a 'corner' in the minimum-time solution obtained with the energy-state model. If the initial and final values of altitude do not lie on the energy-climb trajectory, then additional jumps (crude approximations to dives and zooms) are required at the initial and terminal points. With a singular-perturbation approach, a 'boundary-layer' correction is obtained for each altitude jump, the transonic jump being a so-called 'internal' boundary layer, different in character from the initial and terminal layers. The determination of this internal boundary layer is examined and some computational results for an example presented.

  17. Structural Transitions in Dense Networks

    CERN Document Server

    Lambiotte, R; Bhat, U; Redner, S

    2016-01-01

    We introduce an evolving network model in which a new node attaches to a randomly selected target node and also to each of its neighbors with probability $p$. The resulting network is sparse for $p<\\frac{1}{2}$ and dense (average degree increasing with number of nodes $N$) for $p\\geq \\frac{1}{2}$. In the dense regime, individual networks realizations built by this copying mechanism are disparate and not self-averaging. Further, there is an infinite sequence of structural anomalies at $p=\\frac{2}{3}$, $\\frac{3}{4}$, $\\frac{4}{5}$, etc., where the dependences on $N$ of the number of triangles (3-cliques), 4-cliques, undergo phase transitions. When linking to second neighbors of the target can occur, the probability that the resulting graph is complete---where all nodes are connected---is non-zero as $N\\to\\infty$.

  18. Mixing and Transition Control Studied

    Science.gov (United States)

    1996-01-01

    Considerable progress in understanding nonlinear phenomena in both unbounded and wallbounded shear flow transition has been made through the use of a combination of high- Reynolds-number asymptotic and numerical methods. The objective of this continuing work is to fully understand the nonlinear dynamics so that ultimately (1) an effective means of mixing and transition control can be developed and (2) the source terms in the aeroacoustic noise problem can be modeled more accurately. Two important aspects of the work are that (1) the disturbances evolve from strictly linear instability waves on weakly nonparallel mean flows so that the proper upstream conditions are applied in the nonlinear or wave-interaction streamwise region and (2) the asymptotic formulations lead to parabolic problems so that the question of proper out-flow boundary conditions--still a research issue for direct numerical simulations of convectively unstable shear flows--does not arise. Composite expansion techniques are used to obtain solutions that account for both mean-flow-evolution and nonlinear effects. A previously derived theory for the amplitude evolution of a two-dimensional instability wave in an incompressible mixing layer (which is in quantitative agreement with available experimental data for the first nonlinear saturation stage for a plane-jet shear layer, a circular-jet shear layer, and a mixing layer behind a splitter plate) have been extended to include a wave-interaction stage with a three-dimensional subharmonic. The ultimate wave interaction effects can either give rise to explosive growth or an equilibrium solution, both of which are intimately associated with the nonlinear self-interaction of the three dimensional component. The extended theory is being evaluated numerically. In contrast to the mixing-layer situation, earlier comparisons of theoretical predictions based on asymptotic methods and experiments in wall-bounded shear-flow transition have been somewhat lacking

  19. Corporate governance cycles during transition

    DEFF Research Database (Denmark)

    Mygind, Niels; Demina, Natalia; Gregoric, Aleksandra

    2004-01-01

    -nancial system. To provide simple hypothesis tests, we use Russian enterprise data for 1995-2003 and Slovenian data covering 1998-2003. In spite of differences in institutional development, con-cerning privatization and development of corporate governance institutions, we find that govern-ance cycles are broadly...... of ownership on managers, external domestic and foreign owners. JEL-codes: G3, J5, P2, P3 - Keywords: corporate governance, life-cycle, privatization, ownership change, transition economies, Russia and Slovenia.......Ownership is determined by firm specific factors and the environment. Firms change over their life-cycle. The governance cycle - here defined as changes in identity of the dominant owner and own-ership concentration - is marked by key phases including start-up, growth, and possibly a restructur...

  20. Corporate governance cycles during transition

    DEFF Research Database (Denmark)

    Jones, Derek C.; Mygind, Niels

    2004-01-01

    is faster in Estonia and this can be explained by the relatively fast pace of institutional change and evolution of important gov-ernance institutions, including tough bankruptcy legislation and advances in the financial system. JEL-codes: G3, J5, P2, P3 Keywords: corporate governance, life......We begin by identifying a typical governance life-cycle, defined as changes in ownership structure, and including both the identity of the major owner and ownership concentration. The cycle is marked by key events and phases including start-up, initial growth, mature growth, and possibly a crisis...... and restructuring stage or exit stage. The governance cycle for transitional countries reflects some specific characteristics -e.g. often privatization produces specific initial ownership structures, with an unusually high proportion of insider, especially, employee ownership. Subsequently pres...

  1. Perpetual transitions in Romanian healthcare.

    Science.gov (United States)

    Spiru, Luiza; Traşcu, Răzvan Ioan; Turcu, Ileana; Mărzan, Mircea

    2011-12-01

    Although Romania has a long-lasting tradition in organized medical healthcare, in the last two decades the Romanian healthcare system has been undergoing a perpetual transition with negative effects on all parties involved. The lack of long-term strategic vision, the implementation of initiatives without any impact studies, hence the constant short-term approach from the policy makers, combined with the "inherited" low allocation from GDP to the healthcare system have contributed significantly to its current evolution. Currently, most measures taken are of the "fire-fighting" type, rather than looking to the broader, long time perspective. There should be no wonder then, that predictive and preventive services do not get the proper attention and support. Patient and physicians should step in and take action in regulating a system that was originally designed for them. But until this happens, the organizations with leadership skills and vision need to take action-and this has already started.

  2. PUREX transition project case study

    Energy Technology Data Exchange (ETDEWEB)

    Jasen, W.G.

    1996-04-15

    In December 1992, the US Department of Energy (DOE) directed that the Plutonium-Uranium Extraction (PUREX) Plant be shut down and deactivated because it was no longer needed to support the nation`s production of weapons-grade plutonium. The PUREX/UO{sub 2} Deactivation Project will establish a safe and environmentally secure configuration for the facility and preserve that configuration for 10 years. The 10-year span is used to predict future maintenance requirements and represents the estimated time needed to define, authorize, and initiate the follow-on decontamination and decommissioning activities. Accomplishing the deactivation project involves many activities. Removing major hazards, such as excess chemicals, spent fuel, and residual plutonium are major goals of the project. The scope of the PUREX Transition Project is described within.

  3. Picking the right transition strategy.

    Science.gov (United States)

    Watkins, Michael D

    2009-01-01

    Leaders in transition reflexively rely on the skills and strategies that worked for them in the past. That's a mistake, says Watkins, whose research shows that executives moving into new roles must gain a deep understanding of the situation at hand and adapt to it. To help them accurately assess their organizations and tailor their strategies and styles accordingly, he developed the STARS framework. "STARS" is an acronym for the five common situations leaders move into: start-up, turnaround, accelerated growth, realignment, and sustaining success. Thus, the model outlines the challenges of launching a venture or project; saving a business or initiative that's in serious trouble; dealing with rapid expansion; reenergizing a once-leading company that's now facing problems; and following in the footsteps of a highly regarded leader with a strong legacy of success. Executives can accelerate their immersion in new roles by following certain fundamental principles: Organize to learn about the business, establish A-item priorities, define strategic intent, quickly build the leadership team, secure early wins, and create supportive alliances across the company. But the way those principles should be applied depends very much on the business situation, which the STARS framework can help leaders analyze. Turnarounds and realignments present especially distinct leadership challenges that call for particular transition strategies. Regardless of the business situation, leaders must figure out which things need to happen--perhaps a jump in market share or an expansion into different markets--for their business to achieve its goals. And they must determine which leadership style best fits the new culture they're joining. Armed with such clarity, executives can design effective plans to manage their organizations and themselves.

  4. Labour market transitions and job satisfaction

    OpenAIRE

    Bijwaard, Govert; Van Dijk, Bram; de Koning, Jaap

    2003-01-01

    textabstractThe paper investigates the relationship between job satisfaction and labour market transitions. Using a multinomial logit model, a model is estimated on the basis of individual data in which transitions are explained from individual characteristics, job characteristics, dissatisfaction with the job and discrepancies between the actual and the desired number of hours worked. Transitions can be changes in the hours worked, changes to a different job and/or employers, or combinations...

  5. Cosmological phase transitions from lattice field theory

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2011-11-22

    In this proceedings contribution we discuss the fate of the electroweak and the quantum chromodynamics phase transitions relevant for the early stage of the universe at non-zero temperature. These phase transitions are related to the Higgs mechanism and the breaking of chiral symmetry, respectively. We will review that non-perturbative lattice field theory simulations show that these phase transitions actually do not occur in nature and that physical observables show a completely smooth behaviour as a function of the temperature.

  6. Mortality versus Morbidity in the Demographic Transition

    OpenAIRE

    Aksan, Anna-Maria; Chakraborty, Shankha

    2014-01-01

    The link between the mortality and epidemiological transitions is used to identify the effect of the former on the fertility transition: a mortality transition that is not accompanied by improving morbidity causes slower demographic and economic change. In a model where children may die from infectious disease, childhood health affects human capital and noninfectious-disease-related adult mortality. When child mortality falls from lower prevalence, as it did in western Europe, labor productiv...

  7. Broadband luminescence in liquid-solid transition

    CERN Document Server

    Achilov, M F; Trunilina, O V

    2002-01-01

    Broadband luminescence (BBL) intensity behavior in liquid-solid transition in polyethyleneglycol-600 has been established. Oscillation of BBL intensity observed in liquid-polycrystal transition are not found to observed in liquid-amorphous solid transition. It is shown that application of the theory of electron state tails to interpretation of BBL spectral properties in liquids demands restriction. BBL spectroscopy may be applied for optimization of preparation of polymers with determined properties. (author)

  8. Chaos in a topologically transitive system

    Institute of Scientific and Technical Information of China (English)

    XIONG; Jincheng

    2005-01-01

    The chaotic phenomena have been studied in a topologically transitive system and it has been shown that the erratic time dependence of orbits in such a topologically transitive system is more complicated than what described by the well-known technology "Li-Yorke chaos". The concept "sensitive dependency on initial conditions" has been generalized, and the chaotic phenomena has been discussed for transitive systems with the generalized sensitive dependency property.

  9. Transition in particle-laden flows

    OpenAIRE

    Klinkenberg, J Joy

    2013-01-01

    This thesis presents the study of laminar to turbulent transition of particle laden flows. When a flow becomes turbulent, the drag increases one order of magnitude compared to a laminar flow, therefore, much research is devoted to understand and influence the transition. Previous research at the Linne Flow Centre at KTH has concentrated on the understanding of the bypass transition process of single-phase fluids. Though there are still questions, the principles of this process are now, more o...

  10. Extending Modal Transition Systems with Structured Labels

    DEFF Research Database (Denmark)

    Bauer, Sebastian S.; Juhl, Line; Larsen, Kim Guldstrand

    2012-01-01

    We introduce a novel formalism of label-structured modal transition systems that combines the classical may/must modalities on transitions with structured labels that represent quantitative aspects of the model. On the one hand, the specification formalism is general enough to include models like...... study modal and thorough refinement, determinization, parallel composition, conjunction, quotient, and logical characterization of label-structured modal transition systems....

  11. QGP phase transition and multiplicity fluctuations

    Institute of Scientific and Technical Information of China (English)

    杨纯斌; 王晓荣; 蔡勖

    1997-01-01

    The scaled factorial moments in QGP phase transitions are studied analytically by the extended Ginzburg-Landau model.The dependence of InFq on phase space interval is different for the first- and second-order QGP phase transitions.When lnFq are fitted to polynomials of X=δ1/3,the relative sign between the fitted coefficients of X and bq,l calculated theoretically can be used to judge the order of phase transitions.Two sets of experimental data are reanalysed and the phase transitions are the first order for one set of data but the second order for another.

  12. NO TRANSIT TIMING VARIATIONS IN WASP-4

    Energy Technology Data Exchange (ETDEWEB)

    Petrucci, R.; Schwartz, M.; Buccino, A. P.; Mauas, P. J. D. [Instituto de Astronomía y Física del Espacio (IAFE), Buenos Aires (Argentina); Jofré, E.; Cúneo, V.; Gómez, M. [CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Martínez, C. [Observatorio Astronómico de Córdoba, Córdoba (Argentina)

    2013-12-20

    We present six new transits of the system WASP-4. Together with 28 light curves published in the literature, we perform a homogeneous study of its parameters and search for variations in the transits' central times. The final values agree with those previously reported, except for a slightly lower inclination. We find no significant long-term variations in i or R{sub P} /R {sub *}. The O-C mid-transit times do not show signs of transit timing variations greater than 54 s.

  13. Chirality effects on 2D phase transitions

    DEFF Research Database (Denmark)

    Scalas, E.; Brezesinski, G.; Möhwald, H.

    1996-01-01

    -nearest neighbours (NNN) and an NNN-distorted lattice is observed. At 5 degrees C, the transition pressure is 15 mN m(-1), whereas at 20 degrees C it is 18 mN m(-1). Chirality destroys this transition: the pure enantiomer always exhibits an oblique lattice with tilted molecules, and the azimuths of tilt...... and distortion continuously vary from a direction close to NN to a direction close to NNN. The nature of the phase transition and the influence of chirality on it are discussed within the framework of Landau's theory of phase transitions....

  14. Observations of Extrasolar Planet Transits: What's next?

    Science.gov (United States)

    Rauer, H.

    2014-03-01

    Transits of extrasolar planets are a goldmine for our understanding of the physical nature of planets beyond the Solar System. Measurements of radii from transit observations combined with mass determinations from radial velocity spectroscopy, or transit timing variations, have provided the first indications to the planetary composition and interior structure. It turns out that planets show a much richer diversity than found in our own planetary system, considering e.g. the so-called 'super-Earths', 'mini-Neptunes', and inflated giant planets. Transiting exoplanets also allow for spectroscopic observations of their atmospheres, either during transit or near secondary eclipse. Exoplanets showing transits have therefore been identified as key observables, not only for planet detection, but in particular for investigating further planetary nature. As a result, a new generation of instruments (space- and groundbased) for exoplanet transit observations is already in the construction phase and is planned for the near future. Most of these target specifically stars bright enough for spectroscopic follow-up observations, a èlesson learned' from past transit surveys. A clear goal for future investigations of habitable planets is the detection and characterization of terrestrial planets which potentially could harbor life. This talk will review the status and in particular the future of transit observations, with a focus on rocky planets in the habitable zone of their host stars.

  15. Quark Deconfinement Phase Transition in Neutron Stars

    CERN Document Server

    Alaverdyan, G B

    2009-01-01

    The hadron-quark phase transition in the interior of compact stars is investigated, when the transition proceeds through a mixed phase. The hadronic phase is described in the framework of relativistic mean-field theory, when also the scalar-isovector delta-meson mean-field is taken into account. The changes of the parameters of phase transition caused by the presence of delta-meson field are explored. The results of calculation of structure of the mixed phase (Glendenning construction) are compared with the results of usual first-order phase transition (Maxwell construction).

  16. Many-Body Theory of Atomic Transitions

    Science.gov (United States)

    Holmes, Charles Potter

    This dissertation presents a systematic approach to the derivation of transition widths and cross sections for atomic radiative and/or nonradiative processes. By applying the transition theory of Goldberger and Watson ^1, all transition properties are derived from proper solutions of the time-dependent Schrodinger equation. The focus is on situations where initial and final wave functions are nonorthogonal functions that belong to different self-consistent fields. This approach is particularly useful in the treatment of ionizing transitions where the outgoing free electron sees a different atomic potential from that of the initial bound state. Transition amplitudes are expressed as perturbation expansions in which singularities have been removed algebraically. These singularities are due to states which are degenerate with the initial and final states and represent the competing transition channels. The perturbation expansions show clearly the role of the nonorthogonality of the participating states leading to terms representing "shake" processes competing with higher-order electron correlation processes. Transition amplitudes including all second-order processes, are derived for the following transitions: X-ray, Auger, photoionization, radiative recombination, dielectronic recombination, radiative -Auger. Comparisons are made with the expressions frequently used by other workers. Using a Hartree-Fock-Slater model K- and L-shell X-ray and Auger transition widths are calculated for the range 5 Z Theory, (John Wiley & Sons, New York, 1964), Chapter 8, page 424.

  17. Exposing Baccalaureate Nursing Students to Transitional Care.

    Science.gov (United States)

    OʼConnor, Melissa; Arcamone, Angelina; Amorim, Frances; Hoban, Mary Beth; Boyd, Regina M; Fowler, Lauren; Marcelli, Theresa; Smith, Jacalyn; Nassar, Kathleen; Fitzpatrick, M Louise

    2016-10-01

    Management and facilitation of care transitions from hospital to alternative settings requires skill and attention to avoid adverse events. Several interprofessional organizations and nurse leaders have called for the expansion and redesign of undergraduate nursing curricula to include care transitions. Yet there is little evidence describing how undergraduate baccalaureate nursing students are educated on this critical topic or how successful they are in improving student knowledge about care transitions. To address this gap, an in-classroom and clinical experience was implemented to prepare students to manage and facilitate care transitions from the hospital to alternative settings-including the home. Perceptions of undergraduate nursing students and home healthcare nurse preceptors were assessed via an electronic survey that was emailed to participants. Forty-eight responses to the survey were received. Students agreed this experience contributed to their understanding of caring for adults and older adults who are experiencing a care transition and they had a good understanding of care transitions to apply to their future nursing courses. Home healthcare nurse preceptors agreed they were able to demonstrate transitional care and that students were engaged. Future work should include expanding transitional care immersion to other care settings as well as the inclusion of additional healthcare disciplines in care transition education.

  18. Socioeconomic transitions as common dynamic processes

    DEFF Research Database (Denmark)

    Gundlach, Erich; Paldam, Martin

    Long-run socioeconomic transitions can be observed as stylized facts across countries and over time. For instance, poor countries have more agriculture and less democracy than rich countries, and this pattern also holds within countries for transitions from a traditional to a modern society....... It is shown that the agricultural and the democratic transitions can be partly explained as the outcome of dynamic processes that are shared among countries. We identify the effects of common dynamic processes with panel estimators that allow for heterogeneous country effects and possible cross......-country spillovers. Common dynamic processes appear to be in line with alternative hypotheses on the causes of socioeconomic transitions....

  19. Imagining sustainability: The added value of transition scenarios in transition management

    NARCIS (Netherlands)

    Sondeijker, S.; Geurts, J.; Rotmans, J.; Tukker, A.

    2006-01-01

    Purpose - To address lessons that specify the impact and contribution of current scenario methods when focused on facilitating transition management processes. Design/methodology/approach - Comparative literature review based on transition management and scenario development. Research limitations/ i

  20. Method of construction spatial transition curve

    Directory of Open Access Journals (Sweden)

    S.V. Didanov

    2013-04-01

    Full Text Available Purpose. The movement of rail transport (speed rolling stock, traffic safety, etc. is largely dependent on the quality of the track. In this case, a special role is the transition curve, which ensures smooth insertion of the transition from linear to circular section of road. The article deals with modeling of spatial transition curve based on the parabolic distribution of the curvature and torsion. This is a continuation of research conducted by the authors regarding the spatial modeling of curved contours. Methodology. Construction of the spatial transition curve is numerical methods for solving nonlinear integral equations, where the initial data are taken coordinate the starting and ending points of the curve of the future, and the inclination of the tangent and the deviation of the curve from the tangent plane at these points. System solutions for the numerical method are the partial derivatives of the equations of the unknown parameters of the law of change of torsion and length of the transition curve. Findings. The parametric equations of the spatial transition curve are calculated by finding the unknown coefficients of the parabolic distribution of the curvature and torsion, as well as the spatial length of the transition curve. Originality. A method for constructing the spatial transition curve is devised, and based on this software geometric modeling spatial transition curves of railway track with specified deviations of the curve from the tangent plane. Practical value. The resulting curve can be applied in any sector of the economy, where it is necessary to ensure a smooth transition from linear to circular section of the curved space bypass. An example is the transition curve in the construction of the railway line, road, pipe, profile, flat section of the working blades of the turbine and compressor, the ship, plane, car, etc.

  1. Imagining sustainability: The added value of transition scenarios in transition management

    OpenAIRE

    Sondeijker, Saartje; Geurts, José; Rotmans, Jan; TUKKER, Arnold

    2006-01-01

    textabstractAbstract Purpose – To address lessons that specify the impact and contribution of current scenario methods when focused on facilitating transition management processes. Design/methodology/approach – Comparative literature review based on transition management and scenario development. Research limitations/implications – Need of further systemic thought about the required criteria of transition scenarios and the embedding of scenario use in transition management processes. Practica...

  2. Cosmological Consequences of QCD Phase Transition(s) in Early Universe

    CERN Document Server

    Tawfik, A

    2008-01-01

    We discuss the cosmological consequences of QCD phase transition(s) on the early universe. We argue that our recent knowledge about the transport properties of quark-gluon plasma (QGP) should throw additional lights on the actual time evolution of our universe. Understanding the nature of QCD phase transition(s), which can be studied in lattice gauge theory and verified in heavy ion experiments, provides an explanation for cosmological phenomenon stem from early universe.

  3. Understanding transition performance during offshore IT outsourcing

    NARCIS (Netherlands)

    E. Beulen (Erik); V. Tiwari (Vinay); H.W.G.M. van Heck (Eric)

    2011-01-01

    textabstractPurpose - Within an IT outsourcing relationship, transition represents a critical and complex phase that starts immediately after contract signing. Transition involves handing over outsourced activities from client firm to service provider firm and accompanies a new way of operating. The

  4. Youth Transitions: From Offending to Desistance

    Science.gov (United States)

    Barry, Monica

    2010-01-01

    This article examines youth transitions and youth offending in tandem. It argues that the transition to adulthood is heavily implicated in the fact that most offending occurs in the youth phase. Drawing on a study of 20 male and 20 female persistent young offenders in Scotland, it explores young people's desire for integration with others in the…

  5. Labour market transitions and job satisfaction

    NARCIS (Netherlands)

    G.E. Bijwaard (Govert); A. van Dijk (Bram); J. de Koning (Jaap)

    2003-01-01

    textabstractThe paper investigates the relationship between job satisfaction and labour market transitions. Using a multinomial logit model, a model is estimated on the basis of individual data in which transitions are explained from individual characteristics, job characteristics, dissatisfaction w

  6. Dualities for Logics of Transition Systems

    NARCIS (Netherlands)

    Bonsangue, M.M.; Kurz, A.

    2005-01-01

    We present a general framework for logics of transition systems based on Stone duality. Transition systems are modelled as coalgebras for a functor T on a category X. The propositional logic used to reason about state spaces from X is modelled by the Stone dual A of X (e.g. if X is Stone spaces then

  7. 12 CFR 931.9 - Transition provision.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Transition provision. 931.9 Section 931.9 Banks and Banking FEDERAL HOUSING FINANCE BOARD FEDERAL HOME LOAN BANK RISK MANAGEMENT AND CAPITAL STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.9 Transition provision. (a) In general. Each Bank shall...

  8. 47 CFR 101.4 - Transition plan.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Transition plan. 101.4 Section 101.4 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Applications and Licenses General Filing Requirements § 101.4 Transition plan. (a) All...

  9. Bullying and school transition: Context or development?

    Science.gov (United States)

    Wang, Weijun; Brittain, Heather; McDougall, Patricia; Vaillancourt, Tracy

    2016-01-01

    The relative impact of school transition versus development on peer victimization and bullying perpetration were examined in a natural experiment involving 698 students where half transitioned into middle school from Grade 5 to Grade 6 and the other half remained in their elementary school over the same period. Results indicated that, on average, peer victimization decreased over the transition period while bullying perpetration remained stable for the whole sample. Multilevel modeling was used to investigate the effects of school transition and sex on changes in victimization and perpetration. Results indicated that the effect of transition status on changes in peer victimization was moderated by sex. Middle school transition status predicted decreases in peer victimization for girls, but not for boys, who transitioned. However, school transition status and participants' sex (and their interaction) did not predict changes in perpetration over time. Our findings indicate that changes in student involvement with peer victimization are better understood as a contextual rather than a typical developmental process, whereas bullying perpetration may be better understood as developmental.

  10. Financial system development in transition economies

    NARCIS (Netherlands)

    Hermes, C.L.M.; Lensink, B.W.

    2000-01-01

    This paper provides an overview of the major issues with respect to financial system development in transition economies, which were discussed at a conference in Groningen, the Netherlands, December 1997. After a brief remark on the role of financial system design during economic transition, the pap

  11. Transitions and the Development of Expertise

    Science.gov (United States)

    Hallam, Susan

    2010-01-01

    This paper explores the relationships between the development of expertise and transitions. It sets out what we know about the development of expertise, changes in the brain as expertise develops, and how transitions between different learning contexts and the challenges that they present may impact on developing expertise. It sets out a series of…

  12. Adsorbate Diffusion on Transition Metal Nanoparticles

    Science.gov (United States)

    2015-01-01

    catalysis . KEYWORDS: Heterogeneous catalysis , diffusion, edge barrier, transition metal nanoparticles, DFT calculations 2 Diffusion of adsorbed...species on transition metal surfaces is an important process for thin-film and nanostructure growth and for heterogeneous catalysis , among others.1-4 In...process for heterogeneously catalyzed reactions, and as a result, an atomistic understanding of the diffusion mechanism is very important. We

  13. The Chancellor's Role in a Presidential Transition

    Science.gov (United States)

    Appleton, James R.; Dorsey, Stuart

    2009-01-01

    Successful transitions involving a formal role for the former president, such as chancellor, are rare enough that the authors think theirs is an exceptional experience and is worth sharing, especially given the bulge of presidential retirements anticipated over the next decade. The authors believe that this model of transition can be successful,…

  14. College Students in Transition: An Annotated Bibliography

    Science.gov (United States)

    Foote, Stephanie M., Ed.; Hinkle, Sara M., Ed.; Kranzow, Jeannine, Ed.; Pistilli, Matthew D., Ed.; Miles, LaTonya Rease, Ed.; Simmons, Jannell G., Ed.

    2013-01-01

    The transition from high school to college is an important milestone, but it is only one of many steps in the journey through higher education. This volume is an annotated bibliography of the emerging literature examining the many other transitions students make beyond the first year, including the sophomore year, the transfer experience, and the…

  15. Energy Transition Initiative: Islands Playbook (Book)

    Energy Technology Data Exchange (ETDEWEB)

    2015-01-01

    The Island Energy Playbook (the Playbook) provides an action-oriented guide to successfully initiating, planning, and completing a transition to an energy system that primarily relies on local resources to eliminate a dependence on one or two imported fuels. It is intended to serve as a readily available framework that any community can adapt to organize its own energy transition effort.

  16. Economic development and growth in transition countries

    NARCIS (Netherlands)

    Rusinova, D.T.

    2010-01-01

    The countries of Central and Eastern Europe and the former Soviet Union, commonly referred to as "transition countries", have undergone transformations unparalleled in recent economic history. This book concentrates on three aspects of the transition process: the factors driving growth, the effect o

  17. Quantum Phase Transitions in a Finite System

    CERN Document Server

    Leviatan, A

    2006-01-01

    A general procedure for studying finite-N effects in quantum phase transitions of finite systems is presented and applied to the critical-point dynamics of nuclei undergoing a shape-phase transition of second-order (continuous), and of first-order with an arbitrary barrier.

  18. Performance of Urban Transit in Jordan

    Directory of Open Access Journals (Sweden)

    Dr. Hashem R. Al-Masaeid

    2016-08-01

    Full Text Available Urban public transit has essential and active role for sustainable and balanced socio-economic and environmental development. This study investigated the performance of urban public transit services in three major cities in Jordan, including Amman, Irbid, and Zarqa. Accessibility, mobility, productivity, punctuality, waiting time and comfort of public transit were investigated in the study. Data were obtained from Land Transport RegulatoryCommission of Jordan, municipalities, and field surveys. The accessibility was found to be relatively low in Irbid and Amman city. Also, the results indicated that the mobility and waiting time for public transit were found to be marginally comparable with that in developed countries. In contrast, the productivity of public transit was very high compared with the productivity of transit in developed countries. However, one-quarter of users’ rated the comfort inside public transit as poor. Thus, enhancement of public transit service and introduction of new modes of transport are necessary to ease the existed urban congestion levels

  19. Hysteresis and transition in swirling nonpremixed flames

    NARCIS (Netherlands)

    Tummers, M.J.; Hübner, A.W.; Veen, van E.H.; Hanjalic, K.; Meer, van der Th.H.

    2009-01-01

    Strongly swirling nonpremixed flames are known to exhibit a hysteresis when transiting from an attached long, sooty, yellow flame to a short lifted blue flame, and vice versa. The upward transition (by increasing the air and fuel flow rates) corresponds to a vortex breakdown, i.e. an abrupt change f

  20. Transformative Learning in Managerial Role Transitions

    Science.gov (United States)

    Isopahkala-Bouret, Ulpukka

    2008-01-01

    The purpose of this study is to investigate the nature of learning in work role transitions from specialist roles to managerial roles in a context of a large international technology organisation. Prior theorisation of learning in role transitions has been based on quantitative, psychologically-oriented studies prescribing different role and…

  1. Product of normal edge transitive Cayley graphs

    Directory of Open Access Journals (Sweden)

    Amir Assari

    2014-09-01

    Full Text Available For two normal edge transitive Cayley graphs on two groups H and K whichhave no common direct factor and gcd(|H|/|H'|, |Z(K| = 1 = gcd(|K=K′|,|Z(H|,we consider four standard product of them and proved that only tensor product ofthem can be normal edge transitive.

  2. Transition Experiments: Exploring societal changes towards sustainability

    NARCIS (Netherlands)

    S.J.M. van den Bosch (Suzanne)

    2010-01-01

    textabstractThis PhD thesis presents the outcome of exploratory research on how transition experiments can be used as instruments to further sustainable development. A transition experiment is a specific type of innovation project that is aimed at exploring radically new ways to meet societal needs,

  3. Kevlar: Transitioning Helix from Research to Practice

    Science.gov (United States)

    2015-04-01

    KEVLAR : TRANSITIONING HELIX FROM RESEARCH TO PRACTICE UNIVERSITY OF VIRGINIA APRIL 2015 FINAL TECHNICAL REPORT...DATES COVERED (From - To) FEB 2013 – NOV 2014 4. TITLE AND SUBTITLE KEVLAR : TRANSITIONING HELIX FROM RESEARCH TO PRACTICE 5a. CONTRACT NUMBER...possible exploitation. Our technology, called Kevlar , includes key security technologies are protective transformations and targeted recovery. The

  4. Transition Strategies to Ensure Active Student Engagement

    Science.gov (United States)

    Korbel, Donna M.; McGuire, Joan M.; Banerjee, Manju; Saunders, Sue A.

    2011-01-01

    Transition into college for students with disabilities has been written about extensively over the past decade, due in part to legislative mandates implemented at the secondary level. With significant increases in the number of these students in the college population, a focus on their transition through college is imperative to improve retention…

  5. Factors Affecting Third Culture Kids' (TCKs) Transition

    Science.gov (United States)

    Morales, Antonio

    2015-01-01

    (TCKs) transition becomes challenging for both the student and the school. The programs implemented, or lack thereof, are imperative to the successful transition of TCKs into their new, diverse, multicultural environment. Research has been written on the positive effects and challenges faced by TCKs' transient lifestyle. Although international…

  6. The Structural Phase Transition in Solid DCN

    DEFF Research Database (Denmark)

    Dietrich, O. W.; Mackenzie, Gordon A.; Pawley, G. S.

    1975-01-01

    Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase change from a tetragonal to an orthorhombic form at 160K is a first-order transition. A transverse acoustic phonon mode, which has the symmetry of the phase change, was observed at very low energies...... and showed 'softening' as the transition temperature was approached from above....

  7. Final Technical Report: Variational Transition State Theory

    Energy Technology Data Exchange (ETDEWEB)

    Truhlar, Donald G. [University of Minnesota; Truhlar, Donald G. [University of Minnesota

    2016-09-15

    Complex molecules often have many structures (conformations) of the reactants and the transition states, and these structures may be connected by coupled-mode torsions and pseudorotations; some but not all structures may have hydrogen bonds in the transition state or reagents. A quantitative theory of the reaction rates of complex molecules must take account of these structures, their coupledmode nature, their qualitatively different character, and the possibility of merging reaction paths at high temperature. We have recently developed a coupled-mode theory called multi-structural variational transition state theory (MS-VTST) and an extension, called multi-path variational transition state theory (MP-VTST), that includes a treatment of the differences in the multidimensional tunneling paths and their contributions to the reaction rate. The MP-VTST method was presented for unimolecular reactions in the original paper and has now been extended to bimolecular reactions. The MS-VTST and MPVTST formulations of variational transition state theory include multi-faceted configuration-space dividing surfaces to define the variational transition state. They occupy an intermediate position between single-conformation variational transition state theory (VTST), which has been used successfully for small molecules, and ensemble-averaged variational transition state theory (EAVTST), which has been used successfully for enzyme kinetics. The theories are illustrated and compared here by application to three thermal rate constants for reactions of ethanol with hydroxyl radical—reactions with 4, 6, and 14 saddle points.

  8. 24 CFR 3.230 - Transition plans.

    Science.gov (United States)

    2010-04-01

    ... NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE... that is composed of more than one administratively separate unit may submit either a single transition...) Content of plans. In order to be approved by the Secretary of Education, a transition plan shall:...

  9. 38 CFR 23.230 - Transition plans.

    Science.gov (United States)

    2010-07-01

    ...) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE... that is composed of more than one administratively separate unit may submit either a single transition...) Content of plans. In order to be approved by the Secretary of Education, a transition plan shall:...

  10. 45 CFR 86.17 - Transition plans.

    Science.gov (United States)

    2010-10-01

    ... SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Coverage § 86.17... more than one administratively separate unit may submit either a single transition plan applicable to... order to be approved by the United States Commissioner of Education, a transition plan shall: (1)...

  11. 44 CFR 19.230 - Transition plans.

    Science.gov (United States)

    2010-10-01

    ... HOMELAND SECURITY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES... submit either a single transition plan applicable to all such units, or a separate transition plan applicable to each such unit. (b) Content of plans. In order to be approved by the Secretary of Education,...

  12. 49 CFR 25.230 - Transition plans.

    Science.gov (United States)

    2010-10-01

    ... Transportation Office of the Secretary of Transportation NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION... administratively separate unit may submit either a single transition plan applicable to all such units, or a... Secretary of Education, a transition plan shall: (1) State the name, address, and Federal...

  13. 13 CFR 113.230 - Transition plans.

    Science.gov (United States)

    2010-01-01

    ... Nondiscrimination on the Basis of Sex in Education Programs or Activities Receiving Federal Financial Assistance... that is composed of more than one administratively separate unit may submit either a single transition...) Content of plans. In order to be approved by the Secretary of Education, a transition plan shall:...

  14. 36 CFR 1211.230 - Transition plans.

    Science.gov (United States)

    2010-07-01

    ... RULES NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL... a single transition plan applicable to all such units, or a separate transition plan applicable to each such unit. (b) Content of plans. In order to be approved by the Secretary of Education,...

  15. 32 CFR 196.230 - Transition plans.

    Science.gov (United States)

    2010-07-01

    ...) MISCELLANEOUS NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL... a single transition plan applicable to all such units, or a separate transition plan applicable to each such unit. (b) Content of plans. In order to be approved by the Secretary of Education,...

  16. 22 CFR 146.230 - Transition plans.

    Science.gov (United States)

    2010-04-01

    ... Foreign Relations DEPARTMENT OF STATE CIVIL RIGHTS NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION... administratively separate unit may submit either a single transition plan applicable to all such units, or a... Secretary of Education, a transition plan shall: (1) State the name, address, and Federal...

  17. 43 CFR 41.230 - Transition plans.

    Science.gov (United States)

    2010-10-01

    ... Public Lands: Interior Office of the Secretary of the Interior NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Coverage § 41.230 Transition plans... one administratively separate unit may submit either a single transition plan applicable to all...

  18. 10 CFR 1042.230 - Transition plans.

    Science.gov (United States)

    2010-01-01

    ... DEPARTMENT OF ENERGY (GENERAL PROVISIONS) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR... separate unit may submit either a single transition plan applicable to all such units, or a separate... of Education, a transition plan shall: (1) State the name, address, and Federal Interagency...

  19. 29 CFR 36.230 - Transition plans.

    Science.gov (United States)

    2010-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING... submit either a single transition plan applicable to all such units, or a separate transition plan applicable to each such unit. (b) Content of plans. In order to be approved by the Secretary of Education,...

  20. 40 CFR 5.230 - Transition plans.

    Science.gov (United States)

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Coverage § 5.230 Transition plans... one administratively separate unit may submit either a single transition plan applicable to all...

  1. 45 CFR 618.230 - Transition plans.

    Science.gov (United States)

    2010-10-01

    ... ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE... that is composed of more than one administratively separate unit may submit either a single transition...) Content of plans. In order to be approved by the Secretary of Education, a transition plan shall:...

  2. 28 CFR 54.230 - Transition plans.

    Science.gov (United States)

    2010-07-01

    ... Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Coverage § 54.230 Transition plans... one administratively separate unit may submit either a single transition plan applicable to all...

  3. 6 CFR 17.230 - Transition plans.

    Science.gov (United States)

    2010-01-01

    ... Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Coverage § 17.230 Transition plans... one administratively separate unit may submit either a single transition plan applicable to all...

  4. 10 CFR 5.230 - Transition plans.

    Science.gov (United States)

    2010-01-01

    ... REGULATORY COMMISSION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING... either a single transition plan applicable to all such units, or a separate transition plan applicable to each such unit. (b) Content of plans. In order to be approved by the Secretary of Education,...

  5. 31 CFR 28.230 - Transition plans.

    Science.gov (United States)

    2010-07-01

    ... OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Coverage § 28.230... more than one administratively separate unit may submit either a single transition plan applicable to... order to be approved by the Secretary of Education, a transition plan shall: (1) State the name,...

  6. 14 CFR 1253.230 - Transition plans.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Coverage § 1253.230 Transition plans... one administratively separate unit may submit either a single transition plan applicable to all...

  7. 22 CFR 229.230 - Transition plans.

    Science.gov (United States)

    2010-04-01

    ... Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION... administratively separate unit may submit either a single transition plan applicable to all such units, or a... Secretary of Education, a transition plan shall: (1) State the name, address, and Federal...

  8. 15 CFR 8a.230 - Transition plans.

    Science.gov (United States)

    2010-01-01

    ... SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Coverage § 8a.230... more than one administratively separate unit may submit either a single transition plan applicable to... order to be approved by the Secretary of Education, a transition plan shall: (1) State the name,...

  9. Phase transitions in the web of science

    Science.gov (United States)

    Phillips, J. C.

    2015-06-01

    The Internet age is changing the structure of science, and affecting interdisciplinary interactions. Publication profiles connecting mathematics with molecular biology and condensed matter physics over the last 40 years exhibit common phase transitions indicative of the critical role played by specific interdisciplinary interactions. The strengths of the phase transitions quantify the importance of interdisciplinary interactions.

  10. The dual challenge of sustainability transitions

    NARCIS (Netherlands)

    Kemp, R.; van Lente, H.

    2011-01-01

    In this essay we argue that sustainability transitions include two challenges: on the one hand a long-term change to various technologies and infrastructures, while on the other hand ensuring that consumer criteria change in the same move. Transitions that fail to do so will disappoint in the end. W

  11. Radionuclide Esophageal Transit Scintigraphy in Primary Hypothyroidism

    Science.gov (United States)

    Khan, Shoukat H; Madhu, Vijay P; Rather, Tanveer A; Laway, Bashir A

    2017-01-01

    Background/Aims Esophageal dysmotility is associated with gastrointestinal dysmotility in various systemic and neuroregulatory disorders. Hypothyroidism has been reported to be associated with impaired motor function in esophagus due to accumulation of glycosaminoglycan hyaluronic acid in its soft tissues, leading to changes in various contraction and relaxation parameters of esophagus, particularly in the lower esophageal sphincter. In this study we evaluated esophageal transit times in patients of primary hypothyroidism using the technique of radionuclide esophageal transit scintigraphy. Methods Thirty-one patients of primary hypothyroidism and 15 euthyroid healthy controls were evaluated for esophageal transit time using 15–20 MBq of Technetium-99m sulfur colloid diluted in 10–15 mL of drinking water. Time activity curve was generated for each study and esophageal transit time was calculated as time taken for clearance of 90% radioactive bolus from the region of interest encompassing the esophagus. Esophageal transit time of more than 10 seconds was considered as prolonged. Results Patients of primary hypothyroidism had a significantly increased mean esophageal transit time of 19.35 ± 20.02 seconds in comparison to the mean time of 8.25 ± 1.71 seconds in healthy controls (P hypothyroidism may have subclinical esophageal dysmotility with prolonged esophageal transit time which can be reversible by thyroxine treatment. Prolonged esophageal transit time in primary hypothyroidism may correlate with serum thyroid stimulating hormone levels. PMID:27444283

  12. Magnetic Fields from the Electroweak Phase Transition

    CERN Document Server

    Törnkvist, O

    1998-01-01

    I review some of the mechanisms through which primordial magnetic fields may be created in the electroweak phase transition. I show that no magnetic fields are produced initially from two-bubble collisions in a first-order transition. The initial field produced in a three-bubble collision is computed. The evolution of fields at later times is discussed.

  13. Equinoctial transitions in the ionosphere and thermosphere

    Directory of Open Access Journals (Sweden)

    A. V. Mikhailov

    Full Text Available Equinoctial summer/winter transitions in the parameters of the F2-region are analyzed using ground-based ionosonde and incoherent scatter observations. Average transition from one type of diurnal NmF2 variation to another takes 20–25 days, but cases of very fast (6–10 days transitions are observed as well. Strong day-time NmF2 deviations of both signs from the monthly median, not related to geomagnetic activity, are revealed for the transition periods. Both longitudinal and latitudinal variations take place for the amplitude of such quiet time NmF2 deviations. The summer-type diurnal NmF2 variation during the transition period is characterized by decreased atomic oxygen concentration [O] and a small equatorward thermospheric wind compared to winter-type days with strong poleward wind and increased [O]. Molecular N2 and O2 concentrations remain practically unchanged in such day-to-day transitions. The main cause of the F2-layer variations during the transition periods is the change of atomic oxygen abundance in the thermosphere related to changes of global thermospheric circulation. A possible relationship with an equinoctial transition of atomic oxygen at the E-region heights is discussed.

    Key words. Atmospheric composition and structure (thermosphere – composition and chemistry – Ionosphere (ionosphere- atmosphere interactions; ionospheric disturbances

  14. How Theories of Organization Inform Transition Studies

    NARCIS (Netherlands)

    van Mossel, Allard; van Rijnsoever, Frank; Hekkert, Marko

    2014-01-01

    In historical socio-technical transitions, organizations functioned as the principal drivers of transitions, invented the defining innovations, and created the cognitive and normative rules that led industries to embrace the innovation and associated behavior. Yet, despite their importance, the role

  15. ALICE Transition Radiation Detector (TRD), test beam.

    CERN Multimedia

    2003-01-01

    Electrons and positrons can be discriminated from other charged particles using the emission of transition radiation - X-rays emitted when the particles cross many layers of thin materials. To develop such a Transition Radiation Detector(TRD) for ALICE many detector prototypes were tested in mixed beams of pions and electrons, as in the example shown here.

  16. Branding and Bricolage. Gender, Consumption and Transition

    Science.gov (United States)

    Russell, Rachel; Tyler, Melissa

    2005-01-01

    The analysis presented here focuses on the relationship between femininity, transition and consumer culture. It explores the relationship between gender and consumer culture in the context of a discussion of the transition from childhood to teenage status for a group of young girls, and seeks to make a critical contribution to contemporary debates…

  17. 45 CFR 149.105 - Transition provision.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Transition provision. 149.105 Section 149.105 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES REQUIREMENTS RELATING TO HEALTH CARE ACCESS REQUIREMENTS FOR THE EARLY RETIREE REINSURANCE PROGRAM Reinsurance Amounts § 149.105 Transition provision....

  18. Symmetry Guide to Ferroaxial Transitions

    Science.gov (United States)

    Hlinka, J.; Privratska, J.; Ondrejkovic, P.; Janovec, V.

    2016-04-01

    The 212 species of the structural phase transitions with a macroscopic symmetry breaking are inspected with respect to the occurrence of the ferroaxial order parameter, the electric toroidal moment. In total, 124 ferroaxial species are found, some of them being also fully ferroelectric (62) or fully ferroelastic ones (61). This ensures a possibility of electrical or mechanical switching of ferroaxial domains. Moreover, there are 12 ferroaxial species that are neither ferroelectric nor ferroelastic. For each species, we have also explicitly worked out a canonical form for a set of representative equilibrium property tensors of polar and axial nature in both high-symmetry and low-symmetry phases. This information was gathered into the set of 212 mutually different symbolic matrices, expressing graphically the presence of nonzero independent tensorial components and the symmetry-imposed links between them, for both phases simultaneously. Symmetry analysis reveals the ferroaxiality in several currently debated materials, such as VO2 , LuFe2 O4 , and URu2 Si2 .

  19. Music: Creativity and Structure Transitions

    Science.gov (United States)

    Pietrocini, Emanuela

    Music, compared to other complex forms of representation, is fundamentally characterized by constant evolution and a dynamic succession of structure reference models. This is without taking into account historical perspective, the analysis of forms and styles, or questions of a semantic nature; the observation rather refers to the phenomenology of the music system. The more abstract a compositional model, the greater the number and frequency of variables that are not assimilated to the reference structure; this "interference" which happens more often than not in an apparently casual manner, modifies the creative process to varying but always substantial degrees: locally, it produces a disturbance in perceptive, formal and structural parameters, resulting more often than not in a synaesthetic experience; globally, on the other hand, it defines the terms of a transition to a new state, in which the relations between elements and components modify the behavior of the entire system from which they originated. It is possible to find examples of this phenomenon in the whole range of musical production, in particular in improvisations, in the use of the Basso Continuo, and in some contrapuntal works of the baroque period, music whose temporal dimension can depart from the limits of mensurability and symmetry to define an open compositional environment in continuous evolution.

  20. Development perspective of transitional countries

    Directory of Open Access Journals (Sweden)

    Ilić Bogdan B.

    2005-01-01

    Full Text Available The end of 20th century witnessed the affirmation and development of information technology as well as the transformation of industrial into information, "new economy", which caused changes in people and circumstances. The role and importance of nonhuman factors was increased, causing entrepreneurship and knowledge-based information to become the most significant resources. The Internet became the basis of the "new economy". It changes the way of doing business, studying, researching, communicating and competition. It also reduces operating costs, crosses national borders and leads to the globalization of the world economy. Transitional countries have to fit into modern development flows by formulating their own strategy of national development and establishing their own competitive advantages in conditions of "new economy". These advantages lie predominantly in highly qualified and skilled younger labor which learns fast and adopts new knowledge and skills, through reducing transactional costs, shortening of certain development stages through which developed countries have already gone, using their experience, scientific-technological progress, a rise in work productivity, etc. Experience of other countries should be innovated and adapted to one's own material and social conditions, not copied. This enables the emergence of "European small tigers", which are similar to "Asian small tigers".

  1. Class Transitions in Black Holes

    CERN Document Server

    Chakrabarti, S K

    2005-01-01

    A black hole spectrum is known to change from the hard state to the soft state when the energy spectral index $\\alpha$ ($F_E \\propto E^{-\\alpha}$) in, say, 2-20 keV range changes from $\\alpha \\sim 0.5$ to $\\sim 1.5$. However, this `classical' definition which characterizes black holes like Cyg X-1, becomes less useful for many objects such as GRS 1915+105 in which the spectral slope is seen to vary from one to the other in a matter of seconds and depending on whether or not winds form, the spectral slope also changes. The light curves and the colour-colour diagrams may look completely different on different days depending on the frequency and mode of switching from one spectral state to the other. Though RXTE observations have yielded wealth of information on such `variability classes' in GRS 1915+105, very rarely one has been able to observe how the object goes from one class to the other. In the present review, we discuss possible origins of the class transition and present several examples of such transiti...

  2. Baryon Transition in Holographic QCD

    CERN Document Server

    Li, Siwen

    2015-01-01

    We propose a mechanism of holographic baryon transition in the Sakai-Sugimoto (SS) model: baryons in this model can jump to different states under the mediated effect of gravitons (or glueballs by holography). We consider a time-dependent gravitational perturbation from M5-brane solution of D=11 supergravity and by employing the relations between 11D M-theory and IIA string theory, we get its 10 dimensional counterpart in the SS model. Such a perturbation is received by the D4-branes wrapped on the $S^{4}$ part of the 10D background, namely the baryon vertex. Technically, baryons in the SS model are described by BPST instanton ansatz and their dynamics can be analyzed using the quantum mechanical system in the instanton's moduli space. In this way, different baryonic states are marked by quantum numbers of moduli space quantum mechanics. By holographic spirit, the gravitational perturbation enters the Hamiltonian as a time-dependent perturbation and it is this time-dependent perturbative Hamiltonian produces ...

  3. QCD Phase Transitions, Volume 15

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, T.; Shuryak, E.

    1999-03-20

    The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on the unity of non-perturbative phenomena. For example, we have seen some efforts to connect the lessons from recent progress in Supersymmetric theories with that in QCD, as derived from phenomenology and lattice. Another example is Maldacena conjecture and related development, which connect three things together, string theory, super-gravity and the (N=4) supersymmetric gauge theory. Although the progress mentioned is remarkable by itself, if we would listen to each other more we may have chance to strengthen the field and reach better understanding of the spectacular non-perturbative physics.

  4. Democratization and Transitional Justice in Brazil

    Directory of Open Access Journals (Sweden)

    Maria Paula NASCIMENTO ARAUJO

    2016-05-01

    Full Text Available Brazil experienced a long process of political transition featured by an intense game of political and social forces, in which different actors with different democratization projects clashed. Despite the leadership of the transition process have been in the hands of conservative elites linked to the military dictatorship, broad sectors of the oposition and of the lefts, as well as representants of social movements, disputed the transitional space and expanded the initial design of the regime. This long transition —marked by negotiations, frustrations and resilience— reflected on the transitional justice model adopted by the country. Almost 30 years after the end of military dictatorship, the Truth Commission established by President Dilma Rousseff in 2012, drew attention to issues related to memory, justice and reparation and showed that the democratization process, in some respects, is still incloncluded. This article aims to restore this historical process highlighting some of its characteristics and specificities.

  5. Magnetic phase transitions in layered intermetallic compounds

    Science.gov (United States)

    Mushnikov, N. V.; Gerasimov, E. G.; Rosenfeld, E. V.; Terent'ev, P. B.; Gaviko, V. S.

    2012-10-01

    Magnetic, magnetoelastic, and magnetotransport properties have been studied for the RMn2Si2 and RMn6Sn6 (R is a rare earth metal) intermetallic compounds with natural layered structure. The compounds exhibit wide variety of magnetic structures and magnetic phase transitions. Substitution of different R atoms allows us to modify the interatomic distances and interlayer exchange interactions thus providing the transition from antiferromagnetic to ferromagnetic state. Near the boundary of this transition the magnetic structures are very sensitive to the external field, temperature and pressure. The field-induced transitions are accompanied by considerable change in the sample size and resistivity. It has been shown that various magnetic structures and magnetic phase transitions observed in the layered compounds arise as a result of competition of the Mn-Mn and Mn-R exchange interactions.

  6. Holographic Phase Transition Probed by Nonlocal Observables

    Directory of Open Access Journals (Sweden)

    Xiao-Xiong Zeng

    2016-01-01

    Full Text Available From the viewpoint of holography, the phase structure of a 5-dimensional Reissner-Nordström-AdS black hole is probed by the two-point correlation function, Wilson loop, and entanglement entropy. As the case of thermal entropy, we find for all the probes that the black hole undergoes a Hawking-Page phase transition, a first-order phase transition, and a second-order phase transition successively before it reaches a stable phase. In addition, for these probes, we find that the equal area law for the first-order phase transition is valid always and the critical exponent of the heat capacity for the second-order phase transition coincides with that of the mean field theory regardless of the size of the boundary region.

  7. Using Transiting Planets to Model Starspot Evolution

    CERN Document Server

    Davenport, James R A; Hawley, Suzanne L

    2014-01-01

    Photometry from Kepler has revealed the presence of cool starspots on the surfaces of thousands of stars, presenting a wide range of spot morphologies and lifetimes. Understanding the lifetime and evolution of starspots across the main sequence reveals critical information about the strength and nature of stellar dynamos. We probe the dynamo by modeling the starspot properties over time using Kepler light curves. In particular, we use planetary systems like Kepler 17 that show in-transit starspot crossing features. Spot-occulting transits probe smaller-scale starspot features on the stellar surface along a fixed latitude region. Our approach is novel in modeling both the in- and out-of transit light curve features, allowing us to break fundamental degeneracies between spot size, latitude, and contrast. With continuous monitoring from Kepler we are able to observe small changes in the positions and sizes of spots from many transits, spanning 4 years of data. Additionally, for stars without transiting planets l...

  8. Stainless Steel to Titanium Bimetallic Transitions

    Energy Technology Data Exchange (ETDEWEB)

    Kaluzny, J. A. [Fermilab; Grimm, C. [Fermilab; Passarelli, D. [Fermilab

    2015-01-01

    In order to use stainless steel piping in an LCLS-II (Linac Coherent Light Source Upgrade) cryomodule, stainless steel to titanium bimetallic transitions are needed to connect the stainless steel piping to the titanium cavity helium vessel. Explosion bonded stainless steel to titanium transition pieces and bimetallic transition material samples have been tested. A sample transition tube was subjected to tests and x-ray examinations between tests. Samples of the bonded joint material were impact and tensile tested at room temperature as well as liquid helium temperature. The joint has been used successfully in horizontal tests of LCLS-II cavity helium vessels and is planned to be used in LCLS-II cryomodules. Results of material sample and transition tube tests will be presented.

  9. Automated transit planning, operation, and applications

    CERN Document Server

    Liu, Rongfang

    2016-01-01

    This book analyzes the successful implementations of automated transit in various international locations, such as Paris, Toronto, London, and Kuala Lumpur, and investigates the apparent lack of automated transit applications in the urban environment in the United States. The book begins with a brief definition of automated transit and its historical development. After a thorough description of the technical specifications, the author highlights a few applications from each sub-group of the automated transit spectrum. International case studies display various technologies and their applications, and identify vital factors that affect each system and performance evaluations of existing applications. The book then discusses the planning and operation of automated transit applications at both macro and micro levels. Finally, the book covers a number of less successful concepts, as well as the lessons learned, allow ng readers to gain a comprehensive understanding of the topic.

  10. Molecular precursor routes to transition metal sulfides

    Science.gov (United States)

    Dinnage, Christopher Walker

    This thesis is primarily concerned with the synthesis of homoleptic early transition meta thiolates and the subsequent preparation of bulk and thin-film metal disulfides from these compounds. Chapter 1 gives an introduction into the properties, preparation procedures and uses of bulk and thin-film transition metal disulfides as well as giving an overview of early transition metal thiolates synthesied so far in the literature (for titanium, zirconium, tantalum and niobium). Chapter 2 is concerned with the synthesis of a number of ionic and neutral transition metal thiolates. The main synthetic methodologies discussed in this chapter include substitution reactions of transition metal amides and alkyls with thiols, salt metathesis reactions of transition metal chlorides with alkali metal thiolates or with a base / thiol and the use of Grignard reagents. Chapter 3 discusses the preparation of bulk transition metal disulfides using the thiolates prepared in the previous chapter via a thio "sol-gel" route. The preparation of a range of bulk metal and mixed-metal disulfides using transition metal chlorides and hexamethyldisilathiane is also discussed in this chapter. Finally, chapter 4 is concerned with the attempted preparation of thin-films of some transition metal disulfides. Decomposition studies of some of the thiolates prepared in chapter 2 are discussed using thermal gravimetric analysis. Vapour-phase deposition studies are also explored in order to test the potential of the transition metal thiolates as precursors to the disulfides. Experiments using low-pressure chemical vapour deposition and aerosol-assisted chemical vapour deposition are also described.

  11. Transit-Based Emergency Evacuation with Transit Signal Priority in Sudden-Onset Disaster

    Directory of Open Access Journals (Sweden)

    Ciyun Lin

    2016-01-01

    Full Text Available This study presents methods of transit signal priority without transit-only lanes for a transit-based emergency evacuation in a sudden-onset disaster. Arterial priority signal coordination is optimized when a traffic signal control system provides priority signals for transit vehicles along an evacuation route. Transit signal priority is determined by “transit vehicle arrival time estimation,” “queuing vehicle dissipation time estimation,” “traffic signal status estimation,” “transit signal optimization,” and “arterial traffic signal coordination for transit vehicle in evacuation route.” It takes advantage of the large capacities of transit vehicles, reduces the evacuation time, and evacuates as many evacuees as possible. The proposed methods were tested on a simulation platform with Paramics V6.0. To evaluate and compare the performance of transit signal priority, three scenarios were simulated in the simulator. The results indicate that the methods of this study can reduce the travel times of transit vehicles along an evacuation route by 13% and 10%, improve the standard deviation of travel time by 16% and 46%, and decrease the average person delay at a signalized intersection by 22% and 17% when the traffic flow saturation along an evacuation route is 0.81.0, respectively.

  12. Which transition comes first? Urban and demographic transitions in Belgium and Sweden

    Directory of Open Access Journals (Sweden)

    Philippe Bocquier

    2015-12-01

    Full Text Available Background: Several theories compete to explain the main drivers of urbanisation, past and present, in relation to both demographic transition and economic development. One hypothesis is that rural-to-urban migration is the driver of urbanisation; another is that urban mortality decline actually triggered urban transition. Objective: This paper reconsiders the relationship between demographic (vital migration and urban transitions by analysing the long-term contribution of natural and migratory movements to urban transition. The respective contributions of birth, death, and migration and their timing will indicate whether economic development, through labour force migration, or vital transition mainly determines urban transition. Methods: After examining the spatial dimension of the demographic transition theory, we use 19th and 20th century series on Sweden and Belgium to better identify the migration component of urban transition through the computation of growth difference between urban and rural areas, accounting for the often neglected reclassification effect. Results: In both Sweden and Belgium, migration is the direct or indirect (through reclassification engine of urban transition and its contribution precedes the onset of vital transition, while the vital transition has a secondary, unstable, and negative role in the urban transition. Conclusions: Changes in the economic sphere are reinstated as the underlying cause of population change, acting through the shift of human capital in space. Methodological consequences are then drawn for analysing vital and urban transitions in an increasingly interdependent world. Contribution: The paper contributes to the theoretical literature on urban and demographic transitions in relation to economic development. The proposed method evaluates migration contribution without having to measure it.

  13. The Avahan Transition: Effects of Transition Readiness on Program Institutionalization and Sustained Outcomes.

    Directory of Open Access Journals (Sweden)

    Sachiko Ozawa

    Full Text Available With declines in development assistance for health and growing interest in country ownership, donors are increasingly faced with the task of transitioning health programs to local actors towards a path to sustainability. Yet there is little available guidance on how to measure and evaluate the success of a transition and its subsequent effects. This study assesses the transition of the Avahan HIV/AIDS prevention program in India to investigate how preparations for transition affected continuation of program activities post-transition.Two rounds of two surveys were conducted and supplemented by data from government and Avahan Computerized Management Information Systems (CMIS. Exploratory factor analysis was used to develop two measures: 1 transition readiness pre-transition, and 2 institutionalization (i.e. integration of initial program systems into organizational procedures and behaviors post-transition. A fixed effects model was built to examine changes in key program delivery outcomes over time. An ordinary least square regression was used to assess the relationship between transition readiness and sustainability of service outcomes both directly, and indirectly through institutionalization.Transition readiness data revealed 3 factors (capacity, alignment and communication, on a 15-item scale with adequate internal consistency (alpha 0.73. Institutionalization was modeled as a unidimensional construct, and a 12-item scale demonstrated moderate internal consistency (alpha 0.60. Coverage of key populations and condom distribution were sustained compared to pre-transition levels (p<0.01. Transition readiness, but not institutionalization, predicted sustained outcomes post-transition. Transition readiness did not necessarily lead to institutionalization of key program elements one year after transition.Greater preparedness prior to transition is important to achieve better service delivery outcomes post-transition. This paper illustrates a

  14. Electric Monopole Transition Strengths in 62Ni

    Science.gov (United States)

    Evitts, L. J.; Garnsworthy, A. B.; Kibédi, T.; Moukaddam, M.; Alshahrani, B.; Eriksen, T. K.; Holt, J. D.; Hota, S. S.; Lane, G. J.; Lee, B. Q.; McCormick, B. P.; Palalani, N.; Reed, M. W.; Stroberg, S. R.; Stuchbery, A. E.

    2016-09-01

    Excited states in 62Ni were populated with a (p, p') reaction using the 14UD Pelletron accelerator at the Australian National University. Electric monopole transition strengths, ρ2(E0), were measured through simultaneous detection of the internal conversion electrons and γ rays emitted from the de-excitation of populated states, using the Super-e spectrometer coupled with a germanium detector. The strength of the 02+ to 01+ transition has been measured to be 77-34+23 × 10-3 and agrees with previously reported values. Upper limits have been placed on the 03+ to 01+ and 03+ to 02+ transitions. The measured ρ2(E0) value of the 22+ to 21+ transition in 62Ni has been measured for the first time and found to be one of the largest ρ2(E0) values measured to date in nuclei heavier than Ca. The low-lying states of 62Ni have previously been classified as one- and two-phonon vibrational states based on level energies. The measured electric quadrupole transition strengths are consistent with this interpretation. However as electric monopole transitions are forbidden between states which differ by one phonon number, the simple harmonic quadrupole vibrational picture is not suffcient to explain the large ρ2(E0) value for the 22+ to 21+ transition.

  15. Electric Monopole Transition Strengths in 62Ni

    Directory of Open Access Journals (Sweden)

    Evitts L. J.

    2016-01-01

    Full Text Available Excited states in 62Ni were populated with a (p, p’ reaction using the 14UD Pelletron accelerator at the Australian National University. Electric monopole transition strengths, ρ2(E0, were measured through simultaneous detection of the internal conversion electrons and γ rays emitted from the de-excitation of populated states, using the Super-e spectrometer coupled with a germanium detector. The strength of the 02+ to 01+ transition has been measured to be 77−34+23 × 10−3 and agrees with previously reported values. Upper limits have been placed on the 03+ to 01+ and 03+ to 02+ transitions. The measured ρ2(E0 value of the 22+ to 21+ transition in 62Ni has been measured for the first time and found to be one of the largest ρ2(E0 values measured to date in nuclei heavier than Ca. The low-lying states of 62Ni have previously been classified as one- and two-phonon vibrational states based on level energies. The measured electric quadrupole transition strengths are consistent with this interpretation. However as electric monopole transitions are forbidden between states which differ by one phonon number, the simple harmonic quadrupole vibrational picture is not suffcient to explain the large ρ2(E0 value for the 22+ to 21+ transition.

  16. TRANSITIONAL JUSTICE AND DEMOCRATIC CHANGE: KEY CONCEPTS

    Directory of Open Access Journals (Sweden)

    Elena ANDREEVSKA

    2013-06-01

    Full Text Available This Article proposes a genealogy of transitional justice and focuses on transitional justice as one of the key steps in peace building that needs to be taken to secure a stable democratic future. Transitional justice is a response to systematic or widespread violations of human rights. It seeks recognition for victims and promotion of possibilities for peace, reconciliation and democracy. The paper focuses on key concepts of transitional justice before addressing its traditional components: justice, reparation, truth and institutional reform. This Article meeting point on the transitional process in a society which has experienced a violent conflict and needs adequate mechanisms to deal with the legacies of the past in order to prevent future violence and cover the way for reconciliation and democratic consolidation. It provides key stakeholders with an overview of transitional justice and its different components, while examining key challenges faced by those working in this area. The present paper concludes with some remarks that challenge the traditional concept of transitional justice and its processes in order to initiate important debate on where future work in this field is needed.

  17. Microgravity Two-Phase Flow Transition

    Science.gov (United States)

    Parang, M.; Chao, D.

    1999-01-01

    Two-phase flows under microgravity condition find a large number of important applications in fluid handling and storage, and spacecraft thermal management. Specifically, under microgravity condition heat transfer between heat exchanger surfaces and fluids depend critically on the distribution and interaction between different fluid phases which are often qualitatively different from the gravity-based systems. Heat transfer and flow analysis in two-phase flows under these conditions require a clear understanding of the flow pattern transition and development of appropriate dimensionless scales for its modeling and prediction. The physics of this flow is however very complex and remains poorly understood. This has led to various inadequacies in flow and heat transfer modeling and has made prediction of flow transition difficult in engineering design of efficient thermal and flow systems. In the present study the available published data for flow transition under microgravity condition are considered for mapping. The transition from slug to annular flow and from bubbly to slug flow are mapped using dimensionless variable combination developed in a previous study by the authors. The result indicate that the new maps describe the flow transitions reasonably well over the range of the data available. The transition maps are examined and the results are discussed in relation to the presumed balance of forces and flow dynamics. It is suggested that further evaluation of the proposed flow and transition mapping will require a wider range of microgravity data expected to be made available in future studies.

  18. The Transition to Secondary Progressive Multiple Sclerosis

    Science.gov (United States)

    Wood, Fiona; Brain, Katherine E.; Edwards, Michelle; Jones, Rhiannon; Wallbank, Rachel; Robertson, Neil P.; Edwards, Adrian

    2016-01-01

    Background: Identifying the transition from relapsing-remitting to secondary progressive multiple sclerosis (SPMS) can be challenging for clinicians. Little previous research has explored how professionals experience working with patients during this specific stage of the disease. We explored the experiences of a group of multidisciplinary professionals who support patients in the transition to SPMS to describe this stage from a professional perspective. Methods: This qualitative semistructured interview study included 11 professionals (medical, nursing, and allied health professionals; specialists and generalists) working with patients with MS in South Wales, United Kingdom. Thematic analysis of the interview data was performed. Results: Two overarching themes were identified: the transition and providing support. The transition theme comprised issues related to recognizing and communicating about SPMS. Uncertainty influenced recognizing the transition and knowing how to discuss it with patients. The providing support theme included descriptions of challenging aspects of patient care, providing support for caregivers, using the multidisciplinary team, and working within service constraints. Providing adequate psychological support and engaging patients with self-management approaches were seen as particularly challenging. Conclusions: Caring for patients in the transition to SPMS generates specific challenges for professionals. Further research on health-care interactions and patients'/professionals' experiences regarding the transition phase may help identify strategies for professional development and learning and how to optimize the patient experience at this difficult stage of disease. PMID:27803641

  19. Structural changes concurrent with ferromagnetic transition

    Institute of Scientific and Technical Information of China (English)

    Yang Sen; Bao Hui-Xin; Zhou Chao; Wang Yu; Ren Xiao-Bing; Song Xiao-Ping; Yoshitaka Matsushita

    2013-01-01

    Ferromagnetic transition has generally been considered to involve only an ordering of magnetic moment with no change in the host crystal structure or symmetry,as evidenced by a wealth of crystal structure data from conventional X-ray diffractometry (XRD).However,the existence of magnetostriction in all known ferromagnetic systems indicates that the magnetic moment is coupled to the crystal lattice; hence there is a possibility that magnetic ordering may cause a change in crystal structure.With the development of high-resolution synchrotron XRD,more and more magnetic transitions have been found to be accompanied by simultaneous structural changes.In this article,we review our recent progress in understanding the structural change at a ferromagnetic transition,including synchrotron XRD evidence of structural changes at the ferromagnetic transition,a phenomenological theory of crystal structure changes accompanying ferromagnetic transitions,new insight into magnetic morphotropic phase boundaries (MPB) and so on.Two intriguing implications of non-centric symmetry in the ferromagnetic phase and the first-order nature of ferromagnetic transition are also discussed here.In short,this review is intended to give a self-consistent and logical account of structural change occurring simultaneously with a ferromagnetic transition,which may provide new insight for developing highly magneto-responsive materials.

  20. An Institutional Approach to Understanding Energy Transitions

    Science.gov (United States)

    Koster, Auriane Magdalena

    Energy is a central concern of sustainability because how we produce and consume energy affects society, economy, and the environment. Sustainability scientists are interested in energy transitions away from fossil fuels because they are nonrenewable, increasingly expensive, have adverse health effects, and may be the main driver of climate change. They see an opportunity for developing countries to avoid the negative consequences fossil-fuel-based energy systems, and also to increase resilience, by leap-frogging-over the centralized energy grid systems that dominate the developed world. Energy transitions pose both challenges and opportunities. Obstacles to transitions include 1) an existing, centralized, complex energy-grid system, whose function is invisible to most users, 2) coordination and collective-action problems that are path dependent, and 3) difficulty in scaling up RE technologies. Because energy transitions rely on technological and social innovations, I am interested in how institutional factors can be leveraged to surmount these obstacles. The overarching question that underlies my research is: What constellation of institutional, biophysical, and social factors are essential for an energy transition? My objective is to derive a set of "design principles," that I term institutional drivers, for energy transitions analogous to Ostrom's institutional design principles. My dissertation research will analyze energy transitions using two approaches: applying the Institutional Analysis and Development Framework and a comparative case study analysis comprised of both primary and secondary sources. This dissertation includes: 1) an analysis of the world's energy portfolio; 2) a case study analysis of five countries; 3) a description of the institutional factors likely to promote a transition to renewable-energy use; and 4) an in-depth case study of Thailand's progress in replacing nonrenewable energy sources with renewable energy sources. My research will

  1. Transition from IPv4 to IPv6

    DEFF Research Database (Denmark)

    Henten, Anders; Tadayoni, Reza

    The paper examines the transition from IPv4 to IPv6. More specifically, the aim of the paper is to present information on the status of the transition process and on the drivers and barriers concerning this transition. This includes an update on the availability of IPv4 addresses and on how far...... the adoption of IPv6 has come. It also includes a discussion on what but also who the drivers and barriers are, including an examination of the implications of implementing transfer markets for IPv4 addresses....

  2. Blend Analysis of HATNet Transit Candidates

    Directory of Open Access Journals (Sweden)

    Bakos G.Á.

    2011-02-01

    Full Text Available Candidate transiting planet systems discovered by wide-field groundbased surveys must go through an intensive follow-up procedure to distinguish the true transiting planets from the much more common false positives. Especially pernicious are configurations of three or more stars which produce radial velocity and light curves that are similar to those of single stars transited by a planet. In this contribution we describe the methods used by the HATNet team to reject these blends, giving a few illustrative examples.

  3. Framing of regimes and transition strategies

    DEFF Research Database (Denmark)

    Jensen, Jens Stissing

    2012-01-01

    This article suggests that transition strategies are always formulated in the context of specific representations of the regime and the challenges it faces. It is argued that the framing of a regime affects the envisioning of transition strategies. An analysis of the current development agenda...... for the housing construction sector in Denmark reveals the relevance and impacts of different regime framings. It is proposed that the ability to cope with framing issues as situated and political processes is at the core of the governance of transitions....

  4. Metropolitanization:China’s Transitioning Urbanization Patterns

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Amid larger institutional transitions,China has seen rapid urbanization stimulated by the marketization and new industrialization in the country.Now facing a series of new challenges,the traditional mode of urbanization needs to be changed.History has proven that metropolitanization is a necessary stage of urban development;under the circumstances of China’s current industrialization,metropolitanization emerges as the primary direction in China’s transitioning urbanization.This paper suggests certain measures for boosting metropolitanization and urbanization transition in China.

  5. Chiral transition in a strong magnetic background

    CERN Document Server

    Fraga, Eduardo S

    2008-01-01

    The presence of a strong magnetic background can modify the nature and the dynamics of the chiral phase transition at finite temperature. We compute the modified effective potential in the linear sigma model with quarks to one loop in the $\\bar{MS}$ scheme for $N_{f}=2$. For fields $eB\\sim 5 m_{\\pi}^{2}$ and larger a crossover is turned into a weak first-order transition. We discuss possible implications for non-central heavy ion collisions at RHIC and LHC, and for the primordial QCD transition.

  6. SUSY and the Electroweak Phase Transition

    CERN Document Server

    Farrar, Glennys R S; Farrar, Glennys R.; Losada, Marta

    1996-01-01

    We analyze the effective 3 dimensional theory previously constructed for the MSSM and multi-Higgs models to determine the regions of parameter space in which the electroweak phase transition is sufficiently strong for a $B+L$ asymmetry to survive in the low temperature phase. We find that the inclusion of all supersymmetric scalars and all 1-loop corrections has the effect of enhancing the strength of the phase transition. Without a light stop or extension of the MSSM the phase transition is sufficiently first order only if the lightest Higgs mass $M_{h}\\lsi 70$ GeV and $tan\\beta\\lsi 1.75$.

  7. Graphicality transitions in scale-free networks

    CERN Document Server

    Del Genio, Charo I; Bassler, Kevin E

    2011-01-01

    We study the graphicality of power-law distributed degree sequences, showing that the fraction of graphical sequences undergoes two sharp transitions at the values 0 and 2 of the power-law exponent. We characterize these transitions as first-order, and provide an analytic explanation of their nature. Further numerical calculations, based on extreme value arguments, verify this treatment, and introduce a method to determine transition points for any given degree distribution. Our results reveal a fundamental reason why scale-free networks with no constraints on minimum and maximum degree must be sparse for positive power-law exponents, and dense otherwise.

  8. Transition crossing simulation at the Fermilab Booster

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X.; Drozhdin, A.I.; Pellico, W.; /Fermilab

    2007-06-01

    The demand in high intensity and low emittance of the beam extracted from the Booster requires a better control over the momentum spread growth and bunch length shortening at transition crossing, in order to prevent beam loss and coupled bunch instability. Since the transition crossing involves both longitudinal and transverse dynamics, the recently modified 3-D STRUCT code provides an opportunity to numerically investigate the different transition crossing schemes in the machine environment, and apply the results of simulation to minimize the beam loss and emittance growth operationally.

  9. Transit timing observations from Kepler. V. Transit timing variation candidates in the first sixteen months from polynomial models

    DEFF Research Database (Denmark)

    Ford, E.B.; Ragozzine, D.; Holman, M.J.;

    2012-01-01

    Transit timing variations provide a powerful tool for confirming and characterizing transiting planets, as well as detecting non-transiting planets. We report the results of an updated transit timing variation (TTV) analysis for 1481 planet candidates based on transit times measured during...

  10. Student-Directed Transition Planning: Increasing Student Knowledge and Self-Efficacy in the Transition Planning Process

    Science.gov (United States)

    Woods, Lee L.; Sylvester, Lorraine; Martin, James E.

    2010-01-01

    This study examined the effectiveness of a new school to adult life transition planning lesson package titled "Student-Directed Transition Planning". The "Student-Directed Transition Planning" lessons teach transition terms and concepts to provide a means to increase self-determination skills and student participation in transition IEP…

  11. Potentially exploitable supercritical geothermal resources in the ductile crust

    Science.gov (United States)

    Watanabe, Noriaki; Numakura, Tatsuya; Sakaguchi, Kiyotoshi; Saishu, Hanae; Okamoto, Atsushi; Ingebritsen, Steven E.; Tsuchiya, Noriyoshi

    2017-01-01

    The hypothesis that the brittle-ductile transition (BDT) drastically reduces permeability implies that potentially exploitable geothermal resources (permeability >10-16 m2) consisting of supercritical water could occur only in rocks with unusually high transition temperatures such as basalt. However, tensile fracturing is possible even in ductile rocks, and some permeability-depth relations proposed for the continental crust show no drastic permeability reduction at the BDT. Here we present experimental results suggesting that the BDT is not the first-order control on rock permeability, and that potentially exploitable resources may occur in rocks with much lower BDT temperatures, such as the granitic rocks that comprise the bulk of the continental crust. We find that permeability behaviour for fractured granite samples at 350-500 °C under effective confining stress is characterized by a transition from a weakly stress-dependent and reversible behaviour to a strongly stress-dependent and irreversible behaviour at a specific, temperature-dependent effective confining stress level. This transition is induced by onset of plastic normal deformation of the fracture surface (elastic-plastic transition) and, importantly, causes no `jump' in the permeability. Empirical equations for this permeability behaviour suggest that potentially exploitable resources exceeding 450 °C may form at depths of 2-6 km even in the nominally ductile crust.

  12. Addressing Transition Issues in Languages Education.

    Science.gov (United States)

    Steigler-Peters, Susi; Moran, Wendy; Piccioli, Maria Teresa; Chesterton, Paul

    2003-01-01

    Focuses on what has been learned from the implementation and evaluation of the Australian Language and Continuity Initiative (LCI) in relation to addressing transition issues in language education. (Author/VWL)

  13. Transition Management in a Changing Environment.

    Science.gov (United States)

    Mack, Harold

    1978-01-01

    This case study of organizational change, with transition guidelines, describes how an organization development consultant helped surplus line managers to adjust to reassignments when company retrenchment caused reductions in the number of production workers. (MF)

  14. Social Work Intervention Focused on Transitions

    Science.gov (United States)

    2016-12-19

    Study Focus: 30-day Rehospitalizations Among At-risk Older Adults Randomized to a Social Work-driven Care Transitions Intervention; Heart Disease; Diabetes; Hypertension; Cancer; Depression; Asthma; Chronic Heart Failure; Chronic Obstructive Pulmonary Disease; Stroke

  15. Noisy Transition to Turbulence in Microchannels

    CERN Document Server

    Lissandrello, C; Yakhot, V

    2015-01-01

    Here, we study noisy transition to turbulence in a microchannel. We use a microcantilever sensor embedded in the microchannel wall and perform two sets of experiments in the same microchannel: first, we study transition triggered by the natural imperfections of the walls; subsequently, we study transition under artificially added inlet noise. The two experiments result in random flows in which high-order moments of near-wall fluctuations differ by orders of magnitude. Surprisingly however, the lowest order statistics in both cases appear qualitatively similar and can be described by a proposed noisy Landau equation for a slow mode. The noise, regardless of its origin, regularizes the Landau singularity of the relaxation time and makes transitions driven by different noise sources appear similar.

  16. System Geometries and Transit/Eclipse Probabilities

    Directory of Open Access Journals (Sweden)

    Howard A.

    2011-02-01

    Full Text Available Transiting exoplanets provide access to data to study the mass-radius relation and internal structure of extrasolar planets. Long-period transiting planets allow insight into planetary environments similar to the Solar System where, in contrast to hot Jupiters, planets are not constantly exposed to the intense radiation of their parent stars. Observations of secondary eclipses additionally permit studies of exoplanet temperatures and large-scale exo-atmospheric properties. We show how transit and eclipse probabilities are related to planet-star system geometries, particularly for long-period, eccentric orbits. The resulting target selection and observational strategies represent the principal ingredients of our photometric survey of known radial-velocity planets with the aim of detecting transit signatures (TERMS.

  17. Dimensional phase transitions in small Yukawa clusters

    CERN Document Server

    Sheridan, T E

    2009-01-01

    We investigate the one- to two-dimensional zigzag transition in clusters consisting of a small number of particles interacting through a Yukawa (Debye) potential and confined in a two-dimensional biharmonic potential well. Dusty (complex) plasma clusters with $n \\le 19$ monodisperse particles are characterized experimentally for two different confining wells. The well anisotropy is accurately measured, and the Debye shielding parameter is determined from the longitudinal breathing frequency. Debye shielding is shown to be important. A model for this system is used to predict equilibrium particle configurations. The experiment and model exhibit excellent agreement. The critical value of $n$ for the zigzag transition is found to be less than that predicted for an unshielded Coulomb interaction. The zigzag transition is shown to behave as a continuous phase transition from a one-dimensional to a two-dimensional state, where the state variables are the number of particles, the well anisotropy and the Debye shield...

  18. Semiclassical transition in \\phi^4 theory

    CERN Document Server

    Kyatkin, A B

    1994-01-01

    We have shown an example of semiclassical transition in $\\phi^{4}$ theory with positive coupling constant. This process can be described by the classical $O(4)$-invariant solution, considered on a contour in the complex time plane. The transition is technically analogous to the one-instanton transition in the electroweak model. It is suppressed by the factor $\\exp(-2S_{0})$, where $S_{0}$ is Lipatov instanton action. This process describes a semiclassical transition between two coherent states with much smaller number of particles in the initial state than in the final state. Therefore, it could be relevant to the problem of calculation of amplitudes for multiparticle production in $\\phi^4$-type models.

  19. Physics: Optical transition seen in antihydrogen

    Science.gov (United States)

    Ulmer, Stefan

    2017-01-01

    Precise measurements of antimatter systems might cast light on why the Universe is dominated by matter. The observation of a transition in an antihydrogen atom heralds the next wave of high-precision antimatter studies. See Letter p.506

  20. On primordial equation of state transitions

    CERN Document Server

    Aravind, Aditya; Paban, Sonia

    2016-01-01

    We revisit the physics of transitions from a general equation of state parameter to the final stage of slow-roll inflation. We show that it is unlikely for the modes comprising the cosmic microwave background to contain imprints from a pre-inflationary equation of state transition and still be consistent with observations. We accomplish this by considering observational consistency bounds on the amplitude of excitations resulting from such a transition. As a result, the physics which initially led to inflation likely cannot be probed with observations of the cosmic microwave background. Furthermore, we show that it is unlikely that equation of state transitions may explain the observed low multipole power suppression anomaly.

  1. Observable Signatures of a Classical Transition

    CERN Document Server

    Johnson, Matthew C

    2015-01-01

    Eternal inflation arising from a potential landscape predicts that our universe is one realization of many possible cosmological histories. One way to access different cosmological histories is via the nucleation of bubble universes from a metastable false vacuum. Another way to sample different cosmological histories is via classical transitions, the creation of pocket universes through the collision between bubbles. Using relativistic numerical simulations, we examine the possibility of observationally determining if our observable universe resulted from a classical transition. We find that classical transitions produce spatially infinite, approximately open Friedman-Robertson-Walker universes. The leading set of observables in the aftermath of a classical transition are negative spatial curvature and a contribution to the Cosmic Microwave Background temperature quadrupole. The level of curvature and magnitude of the quadrupole are dependent on the position of the observer, and we determine the possible ran...

  2. A search for transit timing variation

    Directory of Open Access Journals (Sweden)

    Kramm U.

    2011-02-01

    Full Text Available Photometric follow-ups of transiting exoplanets (TEPs may lead to discoveries of additional, less massive bodies in extrasolar systems. This is possible by detecting and then analysing variations in transit timing of transiting exoplanets. In 2009 we launched an international observing campaign, the aim of which is to detect and characterise signals of transit timing variation (TTV in selected TEPs. The programme is realised by collecting data from 0.6-2.2-m telescopes spread worldwide at different longitudes. We present our observing strategy and summarise first results for WASP-3b with evidence for a 15 Earth-mass perturber in an outer 2:1 orbital resonance.

  3. Modeling Network Transition Constraints with Hypergraphs

    DEFF Research Database (Denmark)

    Harrod, Steven

    2011-01-01

    Discrete time dynamic graphs are frequently used to model multicommodity flows or activity paths through constrained resources, but simple graphs fail to capture the interaction effects of resource transitions. The resulting schedules are not operationally feasible, and return inflated objective...

  4. Conductor-insulator quantum phase transitions

    CERN Document Server

    Trivedi, Nandini; Valles, James M

    2012-01-01

    When many particles come together how do they organise themselves? And what destroys this organisation? Combining experiments and theory, this book describes intriguing quantum phases - metals, superconductors and insulators - and transitions between them.

  5. Port Authority of Allegheny County Transit Routes

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Shapefile of Transit Routes - Please refer to each resource for active dates of the route information. Routes change over time,

  6. Transition Programming for Students with Learning Disabilities.

    Science.gov (United States)

    Harrington, Stuart A.

    1997-01-01

    Successful transition programs for students with learning disabilities have some common elements: job-related academic instruction, interpersonal skills development, vocational education, and follow-along counseling after formal schooling ends. (SK)

  7. Transits of Venus and Mercury as muses

    Science.gov (United States)

    Tobin, William

    2013-11-01

    Transits of Venus and Mercury have inspired artistic creation of all kinds. After having been the first to witness a Venusian transit, in 1639, Jeremiah Horrocks expressed his feelings in poetry. Production has subsequently widened to include songs, short stories, novels, novellas, sermons, theatre, film, engravings, paintings, photography, medals, sculpture, stained glass, cartoons, stamps, music, opera, flower arrangements, and food and drink. Transit creations are reviewed, with emphasis on the English- and French-speaking worlds. It is found that transits of Mercury inspire much less creation than those of Venus, despite being much more frequent, and arguably of no less astronomical significance. It is suggested that this is primarily due to the mythological associations of Venus with sex and love, which are more powerful and gripping than Mercury's mythological role as a messenger and protector of traders and thieves. The lesson for those presenting the night sky to the public is that sex sells.

  8. Thermally induced morphological transition of silver fractals

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Solov'yov, Andrey; Kébaili, Nouari;

    2014-01-01

    We present both experimental and theoretical study of thermally induced morphological transition of silver nanofractals. Experimentally, those nanofractals formed from deposition and diffusion of preformed silver clusters on cleaved graphite surfaces exhibit dendritic morphologies that are highly...

  9. Advances in Developing Transitions in Microwave Integrated Circuits

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yun-chuan; WANG Bing-zhong

    2005-01-01

    Advances in developing transitions in microwave integrated circuits during the last ten years are reviewed. Some typical structures of transition are introduced. Transition structures can be classified into two basic types: one is transition between the same kind of transmission lines on different planes of a common substrate, the other transition between different types of transmission lines.Furthermore, future development of transition structures is discussed.

  10. Stochastic relations foundations for Markov transition systems

    CERN Document Server

    Doberkat, Ernst-Erich

    2007-01-01

    Collecting information previously scattered throughout the vast literature, including the author's own research, Stochastic Relations: Foundations for Markov Transition Systems develops the theory of stochastic relations as a basis for Markov transition systems. After an introduction to the basic mathematical tools from topology, measure theory, and categories, the book examines the central topics of congruences and morphisms, applies these to the monoidal structure, and defines bisimilarity and behavioral equivalence within this framework. The author views developments from the general

  11. TRANSITIONAL DISKS AROUND YOUNG LOW MASS STARS

    Directory of Open Access Journals (Sweden)

    P. D'Alessio

    2009-01-01

    have been interpreted as produced by disks with inner holes, which have been classi ed as \\Transitional Disks". These disks are considered the evolutionary link between the full disks typically found around the young T Tauri and Herbig Ae stars, and the debris disks, found around some main sequence stars. In this contribution we summarize the observed/inferred characteristics of these transitional disks and also some of the models proposed to explain their peculiar geometry.

  12. Probabilistic nature in L/H transition

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Shinichiro; Itoh, Sanae-I.; Yagi, Masatoshi [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics; Itoh, Kimitaka; Fukuyama, Atsushi

    1999-11-01

    Statistical picture for an excitation of a plasma transition is examined, which occurs in a strongly turbulent state. The physical picture of transition phenomena is extended to include the statistical variances. The dynamics of the plasma density and turbulent-driven flux is studied with hysteresis nature in the flux-density relation. The probabilistic excitation is predicted and the critical conditions are described by the probabilistic distribution function. The stability for the model equations is also discussed. (author)

  13. Axion dark matter detection using atomic transitions.

    Science.gov (United States)

    Sikivie, P

    2014-11-14

    Dark matter axions may cause transitions between atomic states that differ in energy by an amount equal to the axion mass. Such energy differences are conveniently tuned using the Zeeman effect. It is proposed to search for dark matter axions by cooling a kilogram-sized sample to millikelvin temperatures and count axion induced transitions using laser techniques. This appears to be an appropriate approach to axion dark matter detection in the 10^{-4}  eV mass range.

  14. Childhood Inequality and Transition to Adulthood

    DEFF Research Database (Denmark)

    Loft, Lisbeth Trille Gylling; Fuglsang Olsen, Rikke

    2014-01-01

    reduced when they are facing the transition into adulthood? Using data from the Danish Longitudinal Survey of Children, this study investigates the role of the cognitive, social and emotional development throughout the preschool years (age 7 to 15) with regard to four central markers important...... for a successful transition to adulthood: health outcomes, continued education, labour force participation, and non-involvement in criminal behaviour....

  15. Neutrino Data and Neutrino-Antineutrino Transition

    CERN Document Server

    Alexeyev, E N

    2005-01-01

    A problem, whether a neutrino-antineutrino transition could be responsible for the muon neutrino deficit found in underground experiments (Super-Kamiokande, MACRO, Soudan 2) and in the accelerator long-baseline K2K experiment, is discussed in this paper. The intention of the work is not consideration of concrete models for muon neutrino-antineutrino transition but a desire to attract an attention to another possibility of understanding the nature of the measured muon neutrino deficit in neutrino experiments.

  16. Spinning around in Transition-Metal Chemistry

    OpenAIRE

    Swart, Marcel; Gruden-Pavlović, Maja

    2016-01-01

    Conspectus The great diversity and richness of transition metal chemistry, such as the features of an open d-shell, opened a way to numerous areas of scientific research and technological applications. Depending on the nature of the metal and its environment, there are often several energetically accessible spin states, and the progress in accurate theoretical treatment of this complicated phenomenon is presented in this Account. The spin state energetics of a transition metal complex can be ...

  17. Energy sector transition problems - Croatian experience

    Energy Technology Data Exchange (ETDEWEB)

    Granic, G.; Pesut, D.; Jelavic, B.; Vuk, B.; Jandrilovic, N. [Energy Institute Hrvoje Pozar, Ltd. (Croatia)

    1995-12-31

    This paper analyses the development of energy demand in Croatia in its transition process. It also analyses economic relations and parameters of the energy sector as well as their influence on energy consumption. Possible dynamics of Croatian development and the dynamics of transition are estimated. The development, conditions and relations within the energy sector of Croatia till the year 2010 are also estimated. 2 figs., 3 tabs.

  18. Critical Transitions in Social Network Activity

    DEFF Research Database (Denmark)

    Kuehn, Christian; Martens, Erik Andreas; Romero, Daniel M

    2014-01-01

    A large variety of complex systems in ecology, climate science, biomedicine and engineering have been observed to exhibit tipping points, where the dynamical state of the system abruptly changes. For example, such critical transitions may result in the sudden change of ecological environments...... a priori known events are preceded by variance and autocorrelation growth. Our findings thus clearly establish the necessary starting point to further investigate the relationship between abstract mathematical theory and various classes of critical transitions in social networks....

  19. Axion Dark Matter Detection using Atomic Transitions

    CERN Document Server

    Sikivie, P

    2014-01-01

    Dark matter axions may cause transitions between atomic states that differ in energy by an amount equal to the axion mass. Such energy differences are conveniently tuned using the Zeeman effect. It is proposed to search for dark matter axions by cooling a kilogram-sized sample to milliKelvin temperatures and count axion induced transitions using laser techniques. This appears an appropriate approach to axion dark matter detection in the $10^{-4}$ eV mass range.

  20. Transition Guidelines for A-SMGCS

    OpenAIRE

    Verbeek, René; van Schaik, Frans; Jakobi, Jörn

    2006-01-01

    These Transition Guidelines for Advanced Surface Movement Guidance and Control System (A SMGCS) are intended for use by the stakeholders: airport, ANSP (Air Navigation Service Provider), airline, and industry. The guidelines give an overview of the main STEPS, but not necessarily all steps, for the introduction of and transition to A SMGCS operations at an airport. They address the technical, operational, administrative, training and licensing aspects. The guidelines are no international stan...

  1. PT phase transition in multidimensional quantum systems

    CERN Document Server

    Bender, Carl M

    2012-01-01

    Non-Hermitian PT-symmetric quantum-mechanical Hamiltonians generally exhibit a phase transition that separates two parametric regions, (i) a region of unbroken PT symmetry in which the eigenvalues are all real, and (ii) a region of broken PT symmetry in which some of the eigenvalues are complex. This transition has recently been observed experimentally in a variety of physical systems. Until now, theoretical studies of the PT phase transition have generally been limited to one-dimensional models. Here, four nontrivial coupled PT-symmetric Hamiltonians, $H=p^2/2+x^2/2+q^2/2+y^2/2+igx^2y$, $H=p^2/2+x^2/2+q^2/2+y^2+igx^2y$, $H=p^2/2+x^2/2+q^2/2+y^2/2+r^2/2+z^2/2+igxyz$, and $H=p^2/2+x^2/2+q^2/2+y^2+r^2/2+3z^2/2+igxyz$ are examined. Based on extensive numerical studies, this paper conjectures that all four models exhibit a phase transition. The transitions are found to occur at $g\\approx 0.1$, $g\\approx 0.04$, $g\\approx 0.1$, and $g\\approx 0.05$. These results suggest that the PT phase transition is a robust phen...

  2. An evaluation of transit procurement training.

    Science.gov (United States)

    Noland, Robert B; Weiner, Marc D; Klein, Nicholas J; Puniello, Orin D

    2017-04-01

    We evaluated a training course called "Orientation to Transit Procurement", designed and conducted by the National Transit Institute. This course is designed to provide Federal Transit Administration (FTA) grantees an overview of regulations and best practices related to the procurement process. Our objective in conducting the evaluation was to understand how transit agency staff made changes in procurement practices in response to the course training. The evaluation was mixed mode: an Internet survey followed by in-depth interviews with a small group of respondents. Survey respondents were also provided with an open-ended question providing us with additional context for our evaluation. Results show that the training is substantially successful at meeting the goal of improving procurement practices at transit agencies; indeed, most respondents report making changes at their agencies as the proximate result of the training. This was at odds with our exploration of knowledge of procurement topics, as most respondents gave inaccurate answers on multiple-choice "knowledge questions". This may have been due to question structure or, more likely, the nature of online surveys. Suitable training on the procurement of information technology was also a main concern. The lack of training in this area is indicative of the broader challenge facing public transit agencies in how to incorporate new forms of technology into their existing practices and bureaucratic structures.

  3. Delayed mood transitions in major depressive disorder.

    Science.gov (United States)

    Korf, Jakob

    2014-05-01

    The hypothesis defended here is that the process of mood-normalizing transitions fails in a significant proportion of patients suffering from major depressive disorder. Such a failure is largely unrelated to the psychological content. Evidence for the hypothesis is provided by the highly variable and unpredictable time-courses of the depressive episodes. The main supporting observations are: (1) mood transitions within minutes or days have been reported during deep brain stimulation, naps after sleep deprivation and bipolar mood disorders; (2) sleep deprivation, electroconvulsive treatment and experimental drugs (e.g., ketamine) may facilitate mood transitions in major depressive disorder within hours or a few days; (3) epidemiological and clinical studies show that the time-to-recovery from major depressive disorder can be described with decay models implying very short depressive episodes; (4) lack of relationship between the length of depression and recovery episodes in recurrent depression; (5) mood fluctuations predict later therapeutic success in major depressive disorder. We discuss some recent models aimed to describe random mood transitions. The observations together suggest that the mood transitions have a wide variety of apparently unrelated causes. We suggest that the mechanism of mood transition is compromised in major depressive disorder, which has to be recognized in diagnostic systems.

  4. Making social sense of aquaculture transitions

    Directory of Open Access Journals (Sweden)

    Simon R. Bush

    2014-09-01

    Full Text Available Resilience deals explicitly with change and provides a middle ground between the social and the environmental sciences. However, a growing critique by social scientists questions the ability of resilience thinking to adequately examine the social dimensions of change. The question that emerges is how social scientists should engage with resilience. We addressed this question by comparing resilience with agrarian change and transitions theory, through the backdrop of the fastest growing global food sector, aquaculture. Our analysis showed that each theoretical perspective provides fundamentally different insights into social and environmental transition inherent in the aquaculture sector. Although resilience thinking is best suited to assessing the ecological aspects of production, its systems ontology limits the inclusion of dynamic social relations or innovation. In contrast, agrarian transition enables a more meaningful understanding of how social relations are reconfigured as agrarian society shifts toward more capitalist modes of production, and transitions theory provides insights into social process of innovation. Given the epistemological differences between these theoretical approaches, we argue against attempts that reify systemic thinking by naturalizing social theories and concepts into resilience thinking. Instead, we argue that social theories such as agrarian change and transition theory should be seen as complimentary and that integration should focus on bridging results and insights. Doing so enables a more robust assessment of the social aspects of social-ecological transitions in the aquaculture sector and beyond.

  5. Transit probabilities around hypervelocity and runaway stars

    Science.gov (United States)

    Fragione, G.; Ginsburg, I.

    2017-04-01

    In the blooming field of exoplanetary science, NASA's Kepler Space Telescope has revolutionized our understanding of exoplanets. Kepler's very precise and long-duration photometry is ideal for detecting planetary transits around Sun-like stars. The forthcoming Transiting Exoplanet Survey Satellite (TESS) is expected to continue Kepler's legacy. Along with transits, the Doppler technique remains an invaluable tool for discovering planets. The next generation of spectrographs, such as G-CLEF, promise precision radial velocity measurements. In this paper, we explore the possibility of detecting planets around hypervelocity and runaway stars, which should host a very compact system as consequence of their turbulent origin. We find that the probability of a multiplanetary transit is 10-3 ≲ P ≲ 10-1. We therefore need to observe ∼10-1000 high-velocity stars to spot a transit. However, even if transits are rare around runaway and hypervelocity stars, the chances of detecting such planets using radial velocity surveys is high. We predict that the European Gaia satellite, along with TESS and the new-generation spectrographs G-CLEF and ESPRESSO, will spot planetary systems orbiting high-velocity stars.

  6. Late-time cosmological phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N. (Chicago Univ., IL (USA) Fermi National Accelerator Lab., Batavia, IL (USA))

    1990-11-01

    It is shown that the potential galaxy formation and large-scale structure problems of objects existing at high redshifts (Z {approx gt} 5), structures existing on scales of 100M pc as well as velocity flows on such scales, and minimal microwave anisotropies ({Delta}T/T) {approx lt} 10{sup {minus}5} can be solved if the seeds needed to generate structure form in a vacuum phase transition after decoupling. It is argued that the basic physics of such a phase transition is no more exotic than that utilized in the more traditional GUT scale phase transitions, and that, just as in the GUT case, significant random gaussian fluctuations and/or topological defects can form. Scale lengths of {approximately}100M pc for large-scale structure as well as {approximately}1 M pc for galaxy formation occur naturally. Possible support for new physics that might be associated with such a late-time transition comes from the preliminary results of the SAGE solar neutrino experiment, implying neutrino flavor mixing with values similar to those required for a late-time transition. It is also noted that a see-saw model for the neutrino masses might also imply a tau neutrino mass that is an ideal hot dark matter candidate. However, in general either hot or cold dark matter can be consistent with a late-time transition. 47 refs., 2 figs.

  7. Conceptions of Transitive Maps in Topological Spaces

    Directory of Open Access Journals (Sweden)

    M. Nokhas Murad Kaki

    2014-01-01

    Full Text Available The concepts of topological γ-type transitive maps, α-transitive maps, γ-minimal and α-minimal mappings were introduced by Mohammed Nokhas Murad. . In this paper, the relationship between two different notions of transitive maps, namely topological γ-type transitive maps and topological α-type transitive maps has been studied and some of their properties in two topological spaces (X, τγ and (X, τα, τγ denotes the γ –topology(resp. τα denotes the α–topology of a given topological space (X, τ has been investigated.. Also, we have proved that there exists γ- dense orbit in X, where X is locally γ- compact Hausdorff space and τγ has a countable basis Also, I study the relationship between two types of minimal mappings, namely, γ-minimal mapping and α-minimal mapping, and I will prove that the properties of γ-type transitive, γ-mixing and γ-minimal maps are preserved under γr-conjugacy

  8. Theory of Microcrediting in Transitional Economies

    Directory of Open Access Journals (Sweden)

    Nikola Kadoić

    2009-06-01

    Full Text Available In the early 1970s, Bangladeshi banker and economist Dr. Muhammad Yunus designed microcrediting – a socially sensitive and rightful system of fighting poverty and high unemployment rates. His Grameen Bank for the poorest of the poor in Bangladesh has so far lifted more than 3.2 million of individuals and their families out of poverty. After initial successes at home, microcredit was put into service for reducing unemployment and alleviating poverty in numerous countries throughout the world. This paper explores specific problems that a typical transitional country (like Croatia, is likely to face, with unemployment – the source of a vast number of related problems in a transitional society – as the focal point. The authors have attempted to incorporate particularities of a transitional economy into the original microcrediting principles. As a solution to problems afflicting the domestic economy, the authors define a global microcrediting system framework on the macroeconomic level, assuming at the same time that microcrediting of socially vulnerable groups can resolve many problems of modern transitional societies. Arising from the authors' primary intention – to consider in depth the functionality of microcrediting in general transition conditions – a transitional microcrediting system has been defined in general terms, and a corresponding financial and mathematical model developed.

  9. Transition from galactic to extragalactic cosmic rays

    CERN Document Server

    Berezinsky, V

    2007-01-01

    The transition from galactic to extragalactic cosmic rays is discussed. One of critical indications for transition is given by the Standard Model of Galactic cosmic rays, according to which the maximum energy of acceleration for iron nuclei is of order of $E_{\\rm Fe}^{\\rm max} \\approx 1\\times 10^{17}$ eV. At $E > E_{\\rm Fe}^{\\rm max}$ the spectrum is predicted to be very steep and thus the Standard Model favours the transition at energy not much higher than $E_{\\rm Fe}^{\\rm max}$. As observations are concerned there are two signatures of transition: change of energy spectra and elongation rate (depth of shower maximum in the atmosphere $X_{\\rm max}$ as function of energy). Three models of transition are discussed: dip-based model, mixed composition model and ankle model. In the latter model the transition occurs at the observed spectral feature, ankle, which starts at $E_a \\approx 1\\times 10^{19}$ eV and is characterised by change of mass compostion from galactic iron to extragalactic protons. In the dip mode...

  10. PyTransit: Fast and Easy Exoplanet Transit Modelling in Python

    CERN Document Server

    Parviainen, Hannu

    2015-01-01

    We present a fast and user friendly exoplanet transit light curve modelling package PyTransit, implementing optimised versions of the Gimen\\'ez and the Mandel & Agol transit models. The package offers an object-oriented Python interface to access the two models implemented natively in Fortran with OpenMP parallelisation. A partial OpenCL version of the quadratic Mandel-Agol model is also included for GPU-accelerated computations. The aim of PyTransit is to facilitate the analysis of photometric time series of exoplanet transits consisting of hundreds of thousands of datapoints, and of multi-passband transit light curves from spectrophotometric observations, as a part of a researcher's programming toolkit for building complex, problem-specific, analyses.

  11. Measuring stellar granulation during planet transits

    Science.gov (United States)

    Chiavassa, A.; Caldas, A.; Selsis, F.; Leconte, J.; Von Paris, P.; Bordé, P.; Magic, Z.; Collet, R.; Asplund, M.

    2017-01-01

    Context. Stellar activity and convection-related surface structures might cause bias in planet detection and characterization that use these transits. Surface convection simulations help to quantify the granulation signal. Aims: We used realistic three-dimensional (3D) radiative hydrodynamical (RHD) simulations from the Stagger grid and synthetic images computed with the radiative transfer code Optim3D to model the transits of three prototype planets: a hot Jupiter, a hot Neptune, and a terrestrial planet. Methods: We computed intensity maps from RHD simulations of the Sun and a K-dwarf star at different wavelength bands from optical to far-infrared that cover the range of several ground- and space-based telescopes which observe exoplanet transits. We modeled the transit using synthetic stellar-disk images obtained with a spherical-tile imaging method and emulated the temporal variation of the granulation intensity generating random images covering a granulation time-series of 13.3 h. We measured the contribution of the stellar granulation on the light curves during the planet transit. Results: We identified two types of granulation noise that act simultaneously during the planet transit: (i) the intrinsic change in the granulation pattern with timescale (e.g., 10 min for solar-type stars assumed in this work) is smaller than the usual planet transit ( hours as in our prototype cases); and (ii) the fact that the transiting planet occults isolated regions of the photosphere that differ in local surface brightness as a result of convective-related surface structures. First, we showed that our modeling approach returns granulation timescale fluctuations that are comparable with what has been observed for the Sun. Then, our statistical approach shows that the granulation pattern of solar and K-dwarf-type stars have a non-negligible effect of the light curve depth during the transit, and, consequentially on the determination of the planet transit parameters such as the

  12. Polarization in exoplanetary systems caused by transits, grazing transits, and starspots

    CERN Document Server

    Kostogryz, N M; Berdyugina, S V

    2015-01-01

    We present results of numerical simulations of flux and linear polarization variations in transiting exoplanetary systems, caused by the host star disk symmetry breaking. We consider different configurations of planetary transits depending on orbital parameters. Starspot contribution to the polarized signal is also estimated. Applying the method to known systems and simulating observational conditions, a number of targets is selected where transit polarization effects could be detected. We investigate several principal benefits of the transit polarimetry, particularly, for determining orbital spatial orientation and distinguishing between grazing and near-grazing planets. Simulations show that polarization parameters are also sensitive to starspots, and they can be used to determine spot positions and sizes.

  13. A cloaking device for transiting planets

    Science.gov (United States)

    Kipping, David M.; Teachey, Alex

    2016-06-01

    The transit method is presently the most successful planet discovery and characterization tool at our disposal. Other advanced civilizations would surely be aware of this technique and appreciate that their home planet's existence and habitability is essentially broadcast to all stars lying along their ecliptic plane. We suggest that advanced civilizations could cloak their presence, or deliberately broadcast it, through controlled laser emission. Such emission could distort the apparent shape of their transit light curves with relatively little energy, due to the collimated beam and relatively infrequent nature of transits. We estimate that humanity could cloak the Earth from Kepler-like broad-band surveys using an optical monochromatic laser array emitting a peak power of ˜30 MW for ˜10 hours per year. A chromatic cloak, effective at all wavelengths, is more challenging requiring a large array of tunable lasers with a total power of ˜250 MW. Alternatively, a civilization could cloak only the atmospheric signatures associated with biological activity on their world, such as oxygen, which is achievable with a peak laser power of just ˜160 kW per transit. Finally, we suggest that the time of transit for optical Search for Extraterrestrial Intelligence (SETI) is analogous to the water-hole in radio SETI, providing a clear window in which observers may expect to communicate. Accordingly, we propose that a civilization may deliberately broadcast their technological capabilities by distorting their transit to an artificial shape, which serves as both a SETI beacon and a medium for data transmission. Such signatures could be readily searched in the archival data of transit surveys.

  14. Best Practices for NPT Transit Matching

    Energy Technology Data Exchange (ETDEWEB)

    Gilligan, Kimberly V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Whitaker, J. Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Oakberg, John A. [Tetra Tech, Inc., Oak Ridge, TN (United States); Snow, Catherine [Sno Consulting, LLC, Sandy, UT (United States)

    2016-09-01

    Transit matching is the process for relating or matching reports of shipments and receipts submitted to the International Atomic Energy Agency (IAEA). Transit matching is a component used by the IAEA in drawing safeguards conclusions and performing investigative analysis. Transit matching is part of IAEA safeguards activities and the State evaluation process, and it is included in the annual Safeguards Implementation Report (SIR). Annually, the IAEA currently receives reports of ~900,000 nuclear material transactions, of which ~500,000 are for domestic and foreign transfers. Of these the IAEA software can automatically match (i.e., machine match) about 95% of the domestic transfers and 25% of the foreign transfers. Given the increasing demands upon IAEA resources, it is highly desirable for the machine-matching process to match as many transfers as possible. Researchers at Oak Ridge National Laboratory (ORNL) have conducted an investigation funded by the National Nuclear Security Administration through the Next Generation Safeguards Initiative to identify opportunities to strengthen IAEA transit matching. Successful matching, and more specifically machine matching, is contingent on quality data from the reporting States. In February 2016, ORNL hosted representatives from three States, the IAEA, and Euratom to share results from past studies and to discuss the processes, policies, and procedures associated with State reporting for transit matching. Drawing on each entity s experience and knowledge, ORNL developed a best practices document to be shared with the international safeguards community to strengthen transit matching. This paper shares the recommendations that resulted from this strategic meeting and the next steps being taken to strengthen transit matching.

  15. Membrane Transition Temperature Determines Cisplatin Response.

    Directory of Open Access Journals (Sweden)

    Krishnan Raghunathan

    Full Text Available Cisplatin is a classical chemotherapeutic agent used in treating several forms of cancer including head and neck. However, cells develop resistance to the drug in some patients through a range of mechanisms, some of which are poorly understood. Using isolated plasma membrane vesicles as a model system, we present evidence suggesting that cisplatin induced resistance may be due to certain changes in the bio-physical properties of plasma membranes. Giant plasma membrane vesicles (GPMVs isolated from cortical cytoskeleton exhibit a miscibility transition between a single liquid phase at high temperature and two distinct coexisting liquid phases at low temperature. The temperature at which this transition occurs is hypothesized to reflect the magnitude of membrane heterogeneity at physiological temperature. We find that addition of cisplatin to vesicles isolated from cisplatin-sensitive cells result in a lowering of this miscibility transition temperature, whereas in cisplatin-resistant cells such treatment does not affect the transition temperature. To explore if this is a cause or consequence of cisplatin resistance, we tested if addition of cisplatin in combination with agents that modulate GPMV transition temperatures can affect cisplatin sensitivity. We found that cells become more sensitive to cisplatin when isopropanol, an agent that lowers GPMV transition temperature, was combined with cisplatin. Conversely, cells became resistant to cisplatin when added in combination with menthol that raises GPMV transition temperatures. These data suggest that changes in plasma membrane heterogeneity augments or suppresses signaling events initiated in the plasma membranes that can determine response to cisplatin. We postulate that desired perturbations of membrane heterogeneity could provide an effective therapeutic strategy to overcome cisplatin resistance for certain patients.

  16. Best Practices for NPT Transit Matching

    Energy Technology Data Exchange (ETDEWEB)

    Gilligan, Kimberly V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Whitaker, J. Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Oakberg, John A. [Tetra Tech, Inc., Oak Ridge, TN (United States); Snow, Catherine [Sno Consulting, LLC, Sandy, UT (United States)

    2016-09-01

    Transit matching is the process for relating or matching reports of shipments and receipts submitted to the International Atomic Energy Agency (IAEA). Transit matching is a component used by the IAEA in drawing safeguards conclusions and performing investigative analysis. Transit matching is part of IAEA safeguards activities and the State evaluation process, and it is included in the annual Safeguards Implementation Report (SIR). Annually, the IAEA currently receives reports of ~900,000 nuclear material transactions, of which ~500,000 are for domestic and foreign transfers. Of these the IAEA software can automatically match (i.e., machine match) about 95% of the domestic transfers and 25% of the foreign transfers. Given the increasing demands upon IAEA resources, it is highly desirable for the machine-matching process to match as many transfers as possible. Researchers at Oak Ridge National Laboratory (ORNL) have conducted an investigation funded by the National Nuclear Security Administration through the Next Generation Safeguards Initiative to identify opportunities to strengthen IAEA transit matching. Successful matching, and more specifically machine matching, is contingent on quality data from the reporting States. In February 2016, ORNL hosted representatives from three States, the IAEA, and Euratom to share results from past studies and to discuss the processes, policies, and procedures associated with State reporting for transit matching. Drawing on each entity's experience and knowledge, ORNL developed a best practices document to be shared with the international safeguards community to strengthen transit matching. This paper shares the recommendations that resulted from this strategic meeting and the next steps being taken to strengthen transit matching.

  17. Is the Morin Transition Size Dependent?

    Science.gov (United States)

    Ozdemir, O.

    2007-12-01

    Morin transition temperatures Tm were measured for submicron (SD) synthetic hematites with grain sizes between 120 and 520 nm and on 0.5 and 6 mm (MD) natural single crystals. The Morin transition temperature is quite variable in both SD and MD hematites. Tm ranged from 250 to 260 K for natural crystals and even more widely, from 241 to 254 K, for the more heterogeneous synthetic hematites. The scatter must be due to different methods of preparation, crystal morphology, strain and crystal imperfections that are common for both synthetic and natural crystals. The present Tm data for SD and MD hematites are compatible with published data by other workers in the 100 nm - 10 mm range. In this interval, Tm decreases slightly with decreasing particle size but is almost size independent. However, in nanoparticles with grain sizes between 30 and 90 nm, the spin-flop transition is strongly dependent on particle size: Tm decreases sharply with decreasing size and the transition disappears below 20 nm. This phenomenon is due to surface effects that lead to spin directions deviating from the easy axis. The present SD and MD hematites exhibit a thermal hysteresis in the Morin transition: the values of Tm in cooling and in heating are different. For the same cooling/warming rate, the width of the Morin transition in the submicron crystals is broader than for the natural single crystals. This broadening in SD hematites is directly attributable to the wide distribution of particle sizes. In natural single crystals the entire width of the transition could be due to crystal imperfections and the internal stresses that result from these defects.

  18. Structural Transitions in Topologically Constrained DNA

    Science.gov (United States)

    Leger, J.; Romano, G.; Sarkar, A.; Robert, J.; Bourdieu, L.; Chatenay, D.; Marko, J. F.

    2000-03-01

    We propose a theoretical explanation for results of recent single molecule micromanipulation experiments (Leger et al, PRL 83, 1066, 1999) on double-stranded DNA with fixed linking number. The topological constraint leads to novel structural transitions, including a shift of the usual 60 pN B-form to S-form transition force plateau up to a force of 100 pN when linking is fixed at zero. Our model needs five distinct states to explain the four different observed transitions. The various constant-force plateaus observed for different fixed values of linking correspond to a mixture of different pairs of states, weighted to satisfy the topological constraint. Our model allows us to conclude that sufficiently overtwisted DNA (positive linkage number) undergoes a transition from B-form DNA to a mixture of S-form and P-form DNA at a force plateau near 45 pN, and then to homogeneous P-form DNA at a force plateau near 110 pN. A similar two-step transition occurs for undertwisted DNA, and by analysing the twisting necessary to produce pure S-form DNA we conclude that the S-state has helix repeat of 38 bp. Support from the Whitaker Foundation, the NSF, the ACS-PRF and Research Corporation is gratefully acknowledged.

  19. Explosive percolation transitions in growing networks

    Science.gov (United States)

    Oh, S. M.; Son, S.-W.; Kahng, B.

    2016-03-01

    Recent extensive studies of the explosive percolation (EP) model revealed that the EP transition is second order with an extremely small value of the critical exponent β associated with the order parameter. This result was obtained from static networks, in which the number of nodes in the system remains constant during the evolution of the network. However, explosive percolating behavior of the order parameter can be observed in social networks, which are often growing networks, where the number of nodes in the system increases as dynamics proceeds. However, extensive studies of the EP transition in such growing networks are still missing. Here we study the nature of the EP transition in growing networks by extending an existing growing network model to a general case in which m node candidates are picked up in the Achiloptas process. When m =2 , this model reduces to the existing model, which undergoes an infinite-order transition. We show that when m ≥3 , the transition becomes second order due to the suppression effect against the growth of large clusters. Using the rate-equation approach and performing numerical simulations, we also show that the exponent β decreases algebraically with increasing m , whereas it does exponentially in a corresponding static random network model. Finally, we find that the hyperscaling relations hold but in different forms.

  20. Transit of Exomoon Plasma Tori: New Diagnosis

    CERN Document Server

    Ben-Jaffel, Lotfi

    2014-01-01

    In the solar system, moons largely exceed planets in number. The Kepler database has been shown to be sensitive to exomoon detection down to the mass of Mars, but the first search has been unsuccessful. Here, we use a particles-in-cell code to predict the transit of the plasma torus produced by a satellite. Despite the small size of a moon, the spatial extent of its plasma torus can be large enough to produce substantial transit absorptions. The model is used for the interpretation of Hubble Space Telescope early ingress absorptions apparently observed during WASP-12b and HD 189733b UV transits for which no consistent explanation exists. For HD 189733b an exomoon transiting $\\sim 16$ $R_p$ ahead of the planet and loading $\\sim 10^{29}$ C II ions/s into space is required to explain the tentative early ingress absorption observed for C II. For WASP-12b, a moon transiting $\\sim 6$ $R_p$ ahead from the planet and ejecting $\\sim 10^{28}$ Mg II ions per second is required to explain the NUV early ingress absorption...

  1. Transition paths in molecules at finite temperature

    Science.gov (United States)

    Pinski, F. J.; Stuart, A. M.

    2010-05-01

    In the zero temperature limit, it is well known that in systems evolving via Brownian dynamics, the most likely transition path between reactant and product may be found as a minimizer of the Freidlin-Wentzell action functional. An analog for finite temperature transitions is given by the Onsager-Machlup functional. The purpose of this work is to investigate properties of Onsager-Machlup minimizers. We study transition paths for thermally activated molecules governed by the Langevin equation in the overdamped limit of Brownian dynamics. Using gradient descent in pathspace, we minimize the Onsager-Machlup functional for a range of model problems in one and two dimensions and then for some simple atomic models including Lennard-Jones seven-atom and 38-atom clusters, as well as for a model of vacancy diffusion in a planar crystal. Our results demonstrate interesting effects, which can occur at nonzero temperature, showing transition paths that could not be predicted on the basis of the zero temperature limit. However the results also demonstrate unphysical features associated with such Onsager-Machlup minimizers. As there is a growing literature that addresses transition path sampling by related techniques, these insights add a potentially useful perspective into the interpretation of this body of work.

  2. Modified Magnetohydrodynamics Around the Electroweak Transition

    CERN Document Server

    Pavlovic, Petar; Sigl, Günter

    2016-01-01

    We analyse solutions of the MHD equations around the electroweak transition taking into account the effects of the chiral anomaly. It is shown that a transition that is not of the first order has direct consequences on the evolution of the asymmetry between left- and right-handed leptons. Assuming an initial chiral asymmetry in the symmetric phase at temperatures higher than the transition temperature, as well as the existence of magnetic fields, it is demonstrated that the asymmetry typically grows with time, until it undergoes a fast decrease at the transition, and then eventually gets damped at lower temperatures in the broken phase. We argue that it is unlikely to have any significant magnetic field amplification as a consequence of the electroweak transition in the Standard model, even when the chiral anomaly is introduced. The presence of a chiral asymmetry between left- and right-handed charge carriers naturally leads to the creation of helical magnetic fields from non-helical fields and this can have ...

  3. Contemporary research of dynamically induced phase transitions

    Science.gov (United States)

    Hull, L. M.

    2017-01-01

    Dynamically induced phase transitions in metals, within the present discussion, are those that take place within a time scale characteristic of the shock waves and any reflections or rarefactions involved in the loading structure along with associated plastic flow. Contemporary topics of interest include the influence of loading wave shape, the effect of shear produced by directionality of the loading relative to the sample dimensions and initial velocity field, and the loading duration (kinetic effects, hysteresis) on the appearance and longevity of a transformed phase. These topics often arise while considering the loading of parts of various shapes with high explosives, are typically two or three-dimensional, and are often selected because of the potential of the transformed phase to significantly modify the motion. In this paper, we look at current work on phase transitions in metals influenced by shear reported in the literature, and relate recent work conducted at Los Alamos on iron's epsilon phase transition that indicates a significant response to shear produced by reflected elastic waves. A brief discussion of criteria for the occurrence of stress induced phase transitions is provided. Closing remarks regard certain physical processes, such as fragmentation and jet formation, which may be strongly influenced by phase transitions.

  4. Transition Planning Guide for Parents of Special Education Students. DISD Community Transition Model.

    Science.gov (United States)

    Quinones, Bill; Ozmun, Ellie

    This transition planning guide is intended as a resource for parents of severely handicapped students approaching or at the legal age for leaving public school services and entering community services. The guide was developed after a 2-year transition project, Project Impact, revealed common concerns and questions which parents and teachers…

  5. Transition? What transition? : Changing energy systems in an increasingly carbon constrained world

    NARCIS (Netherlands)

    Mc Cahery, J.A.; Lopez de Silanes, Florencio; de Roode, Alexander

    2014-01-01

    Energy transitions have been taking place continuously since the Industrial Revolution. These transitions primarily involve national energy mixes. In general, countries keep moving up the energy ladder, meaning that they integrate larger and larger proportions of specialized fuels into their energy

  6. Transitions across place and space – Spatial transitions in an Actor Network perspective

    DEFF Research Database (Denmark)

    Kerndrup, Søren; Mosgaard, Mette

    2012-01-01

    network perspective in order to develop the spatial dimensions of transitions. The paper is based on an ongoing research project of spatial dimensions of the transitions in energy production and consumption networks in the northern part of Denmark. The paper show by using an actor network perspective...

  7. Characterizing the Superconducting-to-Normal Transition in Mo/Au Transition-Edge Sensor Bilayers

    Science.gov (United States)

    Smith, Stephen J.; Bandler, Simon R.; Brown, Ari. -D.; Chervenak, Jay A.; Finkbeiner, Fred M.; Iyomoto, Naoko; Kelley, Richard L.; Kilbourne, Caroline A.; Porter, Frederick S.; Sadleir, John E.

    2007-01-01

    We are developing arrays of Mo/Au bilayer transition-edge sensors (TES's) for applications in future X-ray astronomy missions such as NASA's Constellation-X. The physical properties of the superconducting-to-normal transition in our TES bilayers, while often reproducible and characterized, are not well understood. The addition of normal metal features on top of the bilayer are found to change the shape and temperature of the transition, and they typically reduce the unexplained 'excess' noise. In order to understand and potentially optimize the properties of the transition, we have been studying the temperature, widths and current dependence of these transitions. We report on the characterization of devices both deposited on silicon substrates and suspended on thin silicon nitride membranes. This includes key device parameters such as the logarithmic resistance sensitivity with temperature alpha, and the logarithmic resistance sensitivity with current beta, of the phase-transition. We investigate alpha and beta as a function of current, both at fixed and varying bias points in the transition. Using Ginzburg-Landau theory for the current dependence of the superconducting transition temperature, we investigate the relationship between alpha and beta and compare our measured and theoretical estimates.

  8. Transition path time distribution and the transition path free energy barrier.

    Science.gov (United States)

    Pollak, Eli

    2016-10-19

    The recent experimental measurement of the transition path time distributions of proteins presents several challenges to theory. Firstly, why do the fits of the experimental data to a theoretical expression lead to barrier heights which are much lower than the free energies of activation of the observed transitions? Secondly, there is the theoretical question of determining the transition path time distribution, without invoking the Smoluchowski limit. In this paper, we derive an exact expression for a transition path time distribution which is valid for arbitrary memory friction using the normal mode transformation which underlies Kramers' rate theory. We then recall that for low barriers, there is a noticeable difference between the transition path time distribution obtained with absorbing boundary conditions and free boundary conditions. For the former, the transition times are shorter, since recrossings of the boundaries are disallowed. As a result, if one uses the distribution based on absorbing boundary conditions to fit the experimental data, one will find that the transition path barrier will be larger than the values found based on a theory with free boundary conditions. We then introduce the paradigm of a transition path barrier height, and show that one should always expect it to be much smaller than the activation energy.

  9. Anisotropic Effects on Magnetoelastic Transition in Magnetic Molecular Rings

    Institute of Scientific and Technical Information of China (English)

    LI Peng-Fei; CHEN Yu-Guang; CHEN Hong

    2006-01-01

    @@ We numerically study the anisotropic effects on the magnetoelastic transition in an S = 1/2 XXZ model with a finite lattice number. It is found that the order of the magnetoelastic transition is strongly affected by the anisotropy parameter A and there may exist a critical λc dividing the first-order transition and the continuous transition.

  10. Initial infrastructure development strategies for the transition to sustainable mobility

    NARCIS (Netherlands)

    Huetink, F.J.; Vooren, A. van der; Alkemade, F.

    2010-01-01

    Within the Dutch transition policy framework, the transition to hydrogen-based transport is seen as a promising option towards a sustainable transport system. One aspect of such transition processes that is emphasized in transition management is learning about user behaviour and preferences. However

  11. Perceptions of Transition Barriers, Practices, and Solutions in Florida

    Science.gov (United States)

    Lubbers, Joyce H.; Repetto, Jeanne B.; McGorray, Susan P.

    2008-01-01

    To determine teacher working knowledge of transition best practices, the Transition Programs and Services (T-PAS) survey was administered to 2,000 middle and high school teachers and 70 school district transition contacts. Three questions were asked: (a) What barriers exist that hinder the transition process? (b) What effective practices…

  12. Chiral transition and deconfinement in N_f = 2 QCD

    CERN Document Server

    D'Elia, M; Lucini, B; Paffuti, G; Pica, C

    2004-01-01

    The transition is studied by means of a disorder parameter detecting condensation of magnetic monopoles in the vacuum. The deconfining transition is found to coincide with the chiral transition and the susceptibility \\rho, related to the disorder parameter, is consistent with a first order phase transition.

  13. Second-order phase transitions of pure substances

    NARCIS (Netherlands)

    Schaftenaar, H.P.C.

    2009-01-01

    In this report we are dealing with the thermodynamic theory of second-order phase transitions or continuous transitions of unary systems. The first classification of these phase transitions is due to Ehrenfest (1933), based on chemical potentials. First-order transitions are changes in which the der

  14. Microwave-assisted synthesis of transition metal phosphide

    Science.gov (United States)

    Viswanathan, Tito

    2014-12-30

    A method of synthesizing transition metal phosphide. In one embodiment, the method has the steps of preparing a transition metal lignosulfonate, mixing the transition metal lignosulfonate with phosphoric acid to form a mixture, and subjecting the mixture to a microwave radiation for a duration of time effective to obtain a transition metal phosphide.

  15. The ACCESS Transiting Exoplanets Spectroscopy Survey and the Impact of Heterogeneous Stellar Atmospheres on Transit Spectroscopy

    Science.gov (United States)

    Apai, Daniel; Rackham, Benjamin V.; Lopez-Morales, Mercedes; Espinoza, Nestor; Jordan, Andres; Osip, David; Lewis, Nikole K.; Rodler, Florian; Fraine, Jonathan; Morley, Caroline; Fortney, Jonathan J.; Bixel, Alex; ACCESS Team; Earths in Other Solar Systems Team

    2017-01-01

    We present results from the ACCESS survey, a large optical transmission spectroscopy survey of transiting planets. With over 40 transits observed using the IMACS multi-object spectrograph on Magellan, ACCESS is building up the most comprehensive spectral database for transiting exoplanets. The goals of ACCESS are to probe the composition of exoplanet atmospheres as a function planet mass and insolation and stellar properties.We will present a brief overview of the survey and highlight results on multiple targets, including hot jupiters and the sub-nepture GJ1214. I will also report on our study of how stellar heterogeneity impact the transmission spectrum of transiting exoplanets and discuss approaches to correct for this important effect to improve the diagnostic power of transit spectroscopcy.

  16. The transition to chaotic phase synchronization

    DEFF Research Database (Denmark)

    Mosekilde, E.; Laugesen, J. L.; Zhusubaliyev, Zh. T.

    2012-01-01

    The transition to chaotic phase synchronization for a periodically driven spiral-type chaotic oscillator is known to involve a dense set of saddle-node bifurcations. By following the synchronization transition through the cascade of period-doubling bifurcations in a forced Ro¨ssler system......, this paper describes how these saddle-node bifurcations arise and how their characteristic cyclic organisation develops. We identify the cycles that are involved in the various saddle-node bifurcations and describe how the formation of multi-layered resonance cycles in the synchronization domain is related...... varying arterial blood pressure. The paper finally discusses how an alternative transition to chaotic phase synchronization may occur in the mutual synchronization of two chaotically oscillating period-doubling systems....

  17. Human Rights and Transitional Societies: Contemporary Challenges

    DEFF Research Database (Denmark)

    Hansen, Thomas Obel

    2008-01-01

    societies are said to have an obligation to apply criminal justice in dealing with such past violations. In Rwanda, the transitional government decided to prosecute the perpetrators of the 1994 genocide. As a result of widespread participation in the genocide and a devastated legal sector, difficulties...... in respecting the rights of the accused arose. A group of paralegals known as the "Corps of Judicial Defenders" was thus relied upon as to provide legal assistance for genocide suspects, but also for civil parties. This paper describes the work of these paralegals relating to the transitional trials, and, more...... generally, asserts how Judicial Defenders may have contributed to justice in other ways in post conflict Rwanda. The author argues that an efficient transitional justice policy must take sufficiently into account the context of the society in question, and aim at establishing linkages between justice...

  18. The Next Generation Transit Survey - Prototyping Phase

    CERN Document Server

    McCormac, James; Wheatley, Peter; West, Richard; Walker, Simon; Bento, Joao; Skillen, Ian; Faedi, Francesca; Burleigh, Matt; Casewell, Sarah; Chazelas, Bruno; Genolet, Ludovic; Gibson, Neale; Goad, Mike; Lawrie, Katherine; Ryans, Robert; Todd, Ian; Udry, Stephan; Watson, Christopher

    2016-01-01

    We present the prototype telescope for the Next Generation Transit Survey, which was built in the UK in 2008/09 and tested on La Palma in the Canary Islands in 2010. The goals for the prototype system were severalfold: to determine the level of systematic noise in an NGTS-like system; demonstrate that we can perform photometry at the (sub) millimagnitude level on transit timescales across a wide field; show that it is possible to detect transiting super-Earth and Neptune-sized exoplanets and prove the technical feasibility of the proposed planet survey. We tested the system for around 100 nights and met each of the goals above. Several key areas for improvement were highlighted during the prototyping phase. They have been subsequently addressed in the final NGTS facility which was recently commissioned at ESO Cerro Paranal, Chile.

  19. Quantum phase transitions with dynamical flavors

    CERN Document Server

    Bea, Yago; Ramallo, Alfonso V

    2016-01-01

    We study the properties of a D6-brane probe in the ABJM background with smeared massless dynamical quarks in the Veneziano limit. Working at zero temperature and non-vanishing charge density, we show that the system undergoes a quantum phase transition in which the topology of the brane embedding changes from a black hole to a Minkowski embedding. In the unflavored background the phase transition is of second order and takes place when the charge density vanishes. We determine the corresponding critical exponents and show that the scaling behavior near the quantum critical point has multiplicative logarithmic corrections. In the background with dynamical quarks the phase transition is of first order and occurs at non-zero charge density. In this case we compute the discontinuity of several physical quantities as functions of the number $N_f$ of unquenched quarks of the background.

  20. Going to the fare (Rapid transit)

    Energy Technology Data Exchange (ETDEWEB)

    Myers, E.T.

    1977-04-01

    A survey of rider responses to fare increases revealed that a fare increase will generally result in a ridership loss on mass transit systems, while commuter train ridership may rise under the same increase. This is because the suburban commuter very often depends more on such transportation than the urban rider does, as the latter can sometimes walk to his destination, especially if the fare becomes prohibitive. Different approaches to setting urban transit fares and commuter fares and the effect of increasing or decreasing fares on ridership are explored for Philadelphia's SEPTA lines, San Francisco's BART, Chicago's CTA and North Western commuter lines, Boston's MBTA, Cleveland's Regional Transit Authority, and the New York-New Jersey Port Authority's Lindenwold line. (1 graph, 2 photos)