Power-law versus log-law in wall-bounded turbulence: A large-eddy simulation perspective

Science.gov (United States)

Cheng, W.; Samtaney, R.

2014-01-01

The debate whether the mean streamwise velocity in wall-bounded turbulent flows obeys a log-law or a power-law scaling originated over two decades ago, and continues to ferment in recent years. As experiments and direct numerical simulation can not provide sufficient clues, in this study we present an insight into this debate from a large-eddy simulation (LES) viewpoint. The LES organically combines state-of-the-art models (the stretched-vortex model and inflow rescaling method) with a virtual-wall model derived under different scaling law assumptions (the log-law or the power-law by George and Castillo ["Zero-pressure-gradient turbulent boundary layer," Appl. Mech. Rev. 50, 689 (1997)]). Comparison of LES results for Reθ ranging from 105 to 1011 for zero-pressure-gradient turbulent boundary layer flows are carried out for the mean streamwise velocity, its gradient and its scaled gradient. Our results provide strong evidence that for both sets of modeling assumption (log law or power law), the turbulence gravitates naturally towards the log-law scaling at extremely large Reynolds numbers.

Power-law versus log-law in wall-bounded turbulence: A large-eddy simulation perspective

KAUST Repository

Cheng, W.

2014-01-29

The debate whether the mean streamwise velocity in wall-bounded turbulent flows obeys a log-law or a power-law scaling originated over two decades ago, and continues to ferment in recent years. As experiments and direct numerical simulation can not provide sufficient clues, in this study we present an insight into this debate from a large-eddy simulation (LES) viewpoint. The LES organically combines state-of-the-art models (the stretched-vortex model and inflow rescaling method) with a virtual-wall model derived under different scaling law assumptions (the log-law or the power-law by George and Castillo [“Zero-pressure-gradient turbulent boundary layer,” Appl. Mech. Rev.50, 689 (1997)]). Comparison of LES results for Re θ ranging from 105 to 1011 for zero-pressure-gradient turbulent boundary layer flows are carried out for the mean streamwise velocity, its gradient and its scaled gradient. Our results provide strong evidence that for both sets of modeling assumption (log law or power law), the turbulence gravitates naturally towards the log-law scaling at extremely large Reynolds numbers.

Cosmological special relativity the large scale structure of space, time and velocity

CERN Document Server

Carmeli, Moshe

2002-01-01

This book presents Einstein's theory of space and time in detail, and describes the large-scale structure of space, time and velocity as a new cosmological special relativity. A cosmological Lorentz-like transformation, which relates events at different cosmic times, is derived and applied. A new law of addition of cosmic times is obtained, and the inflation of the space at the early universe is derived, both from the cosmological transformation. The relationship between cosmic velocity, acceleration and distances is given. In the appendices gravitation is added in the form of a cosmological g

Auditory velocity discrimination in the horizontal plane at very high velocities.

Science.gov (United States)

Frissen, Ilja; Féron, François-Xavier; Guastavino, Catherine

2014-10-01

We determined velocity discrimination thresholds and Weber fractions for sounds revolving around the listener at very high velocities. Sounds used were a broadband white noise and two harmonic sounds with fundamental frequencies of 330 Hz and 1760 Hz. Experiment 1 used velocities ranging between 288°/s and 720°/s in an acoustically treated room and Experiment 2 used velocities between 288°/s and 576°/s in a highly reverberant hall. A third experiment addressed potential confounds in the first two experiments. The results show that people can reliably discriminate velocity at very high velocities and that both thresholds and Weber fractions decrease as velocity increases. These results violate Weber's law but are consistent with the empirical trend observed in the literature. While thresholds for the noise and 330 Hz harmonic stimulus were similar, those for the 1760 Hz harmonic stimulus were substantially higher. There were no reliable differences in velocity discrimination between the two acoustical environments, suggesting that auditory motion perception at high velocities is robust against the effects of reverberation. Copyright © 2014 Elsevier B.V. All rights reserved.

The analog of Blanc's law for drift velocities of electrons in gas mixtures in weakly ionized plasma

International Nuclear Information System (INIS)

Chiflikian, R.V.

1995-01-01

The analog of Blanc's law for drift velocities of electrons in multicomponent gas mixtures in weakly ionized spatially homogeneous low-temperature plasma is derived. The obtained approximate-analytical expressions are valid for average electron energy in the 1--5 eV range typical for plasma conditions of low-pressure direct current (DC) discharges. The accuracy of these formulas is ±5%. The analytical criterion of the negative differential conductivity (NDC) of electrons in binary mixtures of gases is obtained. NDC of electrons is predicted in He:Kr and He:Xe rare gas mixtures. copyright 1995 American Institute of Physics

Power-law versus log-law in wall-bounded turbulence: A large-eddy simulation perspective

KAUST Repository

Cheng, W.; Samtaney, Ravi

2014-01-01

The debate whether the mean streamwise velocity in wall-bounded turbulent flows obeys a log-law or a power-law scaling originated over two decades ago, and continues to ferment in recent years. As experiments and direct numerical simulation can

Collective cell migration without proliferation: density determines cell velocity and wave velocity

Science.gov (United States)

Tlili, Sham; Gauquelin, Estelle; Li, Brigitte; Cardoso, Olivier; Ladoux, Benoît; Delanoë-Ayari, Hélène; Graner, François

2018-05-01

Collective cell migration contributes to embryogenesis, wound healing and tumour metastasis. Cell monolayer migration experiments help in understanding what determines the movement of cells far from the leading edge. Inhibiting cell proliferation limits cell density increase and prevents jamming; we observe long-duration migration and quantify space-time characteristics of the velocity profile over large length scales and time scales. Velocity waves propagate backwards and their frequency depends only on cell density at the moving front. Both cell average velocity and wave velocity increase linearly with the cell effective radius regardless of the distance to the front. Inhibiting lamellipodia decreases cell velocity while waves either disappear or have a lower frequency. Our model combines conservation laws, monolayer mechanical properties and a phenomenological coupling between strain and polarity: advancing cells pull on their followers, which then become polarized. With reasonable values of parameters, this model agrees with several of our experimental observations. Together, our experiments and model disantangle the respective contributions of active velocity and of proliferation in monolayer migration, explain how cells maintain their polarity far from the moving front, and highlight the importance of strain-polarity coupling and density in long-range information propagation.

Environmental law in Thuringia. Text collection with introduction. Pt. 1. Waste law, nuclear, radiation and energy law, soil protection law and land reparcelling, forestry law, fishing and hunting law

International Nuclear Information System (INIS)

Schneider, Matthias Werner

2015-01-01

The volume 1 of the collection on the Thuringian Environmental Law contains additional to a detailed introduction: - Waste management - Nuclear, radiation and energy law - Soil protection law and land reparcelling - Forestry, fishery and hunting law. [de

Derivation of the Biot-Savart Law from Ampere's Law Using the Displacement Current

Science.gov (United States)

Buschauer, Robert

2013-01-01

The equation describing the magnetic field due to a single, nonrelativistic charged particle moving at constant velocity is often referred to as the "Biot-Savart law for a point charge." Introductory calculus-based physics books usually state this law without proof. Advanced texts often present it either without proof or as a special…

Flow-Field Characteristics of High-Temperature Annular Buoyant Jets and Their Development Laws Influenced by Ventilation System

Directory of Open Access Journals (Sweden)

Yi Wang

2013-01-01

Full Text Available The flow-field characteristics of high-temperature annular buoyant jets as well as the development laws influenced by ventilation system were studied using numerical methods to eliminate the pollutants effectively in this paper. The development laws of high-temperature annular buoyant jets were analyzed and compared with previous studies, including radial velocity distribution, axial velocity and temperature decay, reattachment position, cross-section diameter, volumetric flow rate, and velocity field characteristics with different pressures at the exhaust hood inlet. The results showed that when the ratio of outer diameter to inner diameter of the annulus was smaller than 5/2, the flow-field characteristics had significant difference compared to circular buoyant jets with the same outer diameter. For similar diameter ratios, reattachment in this paper occurred further downstream in contrast to previous study. Besides, the development laws of volumetric flow rate and cross-section diameter were given with different initial parameters. In addition, through analyzing air distribution characteristics under the coupling effect of high-temperature annular buoyant jets and ventilation system, it could be found that the position where maximum axial velocity occurred was changing gradually when the pressure at the exhaust hood inlet changed from 0 Pa to −5 Pa.

Flow-field characteristics of high-temperature annular buoyant jets and their development laws influenced by ventilation system.

Science.gov (United States)

Wang, Yi; Huang, Yanqiu; Liu, Jiaping; Wang, Hai; Liu, Qiuhan

2013-01-01

The flow-field characteristics of high-temperature annular buoyant jets as well as the development laws influenced by ventilation system were studied using numerical methods to eliminate the pollutants effectively in this paper. The development laws of high-temperature annular buoyant jets were analyzed and compared with previous studies, including radial velocity distribution, axial velocity and temperature decay, reattachment position, cross-section diameter, volumetric flow rate, and velocity field characteristics with different pressures at the exhaust hood inlet. The results showed that when the ratio of outer diameter to inner diameter of the annulus was smaller than 5/2, the flow-field characteristics had significant difference compared to circular buoyant jets with the same outer diameter. For similar diameter ratios, reattachment in this paper occurred further downstream in contrast to previous study. Besides, the development laws of volumetric flow rate and cross-section diameter were given with different initial parameters. In addition, through analyzing air distribution characteristics under the coupling effect of high-temperature annular buoyant jets and ventilation system, it could be found that the position where maximum axial velocity occurred was changing gradually when the pressure at the exhaust hood inlet changed from 0 Pa to -5 Pa.

Modified Feynman ratchet with velocity-dependent fluctuations

Directory of Open Access Journals (Sweden)

Jack Denur

2004-03-01

Full Text Available Abstract: The randomness of Brownian motion at thermodynamic equilibrium can be spontaneously broken by velocity-dependence of fluctuations, i.e., by dependence of values or probability distributions of fluctuating properties on Brownian-motional velocity. Such randomness-breaking can spontaneously obtain via interaction between Brownian-motional Doppler effects --- which manifest the required velocity-dependence --- and system geometrical asymmetry. A non random walk is thereby spontaneously superposed on Brownian motion, resulting in a systematic net drift velocity despite thermodynamic equilibrium. The time evolution of this systematic net drift velocity --- and of velocity probability density, force, and power output --- is derived for a velocity-dependent modification of Feynman's ratchet. We show that said spontaneous randomness-breaking, and consequent systematic net drift velocity, imply: bias from the Maxwellian of the system's velocity probability density, the force that tends to accelerate it, and its power output. Maximization, especially of power output, is discussed. Uncompensated decreases in total entropy, challenging the second law of thermodynamics, are thereby implied.

Bulk velocity extraction for nano-scale Newtonian flows

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wenfei, E-mail: zwenfei@gmail.com [Key Laboratory of Mechanical Reliability for Heavy Equipments and Large Structures of Hebei Province, Yanshan University, Qinhuangdao 066004 (China); Sun, Hongyu [Key Laboratory of Mechanical Reliability for Heavy Equipments and Large Structures of Hebei Province, Yanshan University, Qinhuangdao 066004 (China)

2012-04-16

The conventional velocity extraction algorithm in MDS method has difficulty to determine the small flow velocity. This study proposes a new method to calculate the bulk velocity in nano-flows. Based on the Newton's law of viscosity, according to the calculated viscosities and shear stresses, the flow velocity can be obtained by numerical integration. This new method can overcome the difficulty existed in the conventional MDS method and improve the stability of the computational process. Numerical results show that this method is effective for the extraction of bulk velocity, no matter the bulk velocity is large or small. -- Highlights: ► Proposed a new method to calculate the bulk velocity in nano-flows. ► It is effective for the extraction of small bulk velocity. ► The accuracy, convergence and stability of the new method is good.

Bulk velocity extraction for nano-scale Newtonian flows

International Nuclear Information System (INIS)

Zhang, Wenfei; Sun, Hongyu

2012-01-01

The conventional velocity extraction algorithm in MDS method has difficulty to determine the small flow velocity. This study proposes a new method to calculate the bulk velocity in nano-flows. Based on the Newton's law of viscosity, according to the calculated viscosities and shear stresses, the flow velocity can be obtained by numerical integration. This new method can overcome the difficulty existed in the conventional MDS method and improve the stability of the computational process. Numerical results show that this method is effective for the extraction of bulk velocity, no matter the bulk velocity is large or small. -- Highlights: ► Proposed a new method to calculate the bulk velocity in nano-flows. ► It is effective for the extraction of small bulk velocity. ► The accuracy, convergence and stability of the new method is good.

A Physics-Based Rock Friction Constitutive Law: Steady State Friction

Science.gov (United States)

Aharonov, Einat; Scholz, Christopher H.

2018-02-01

Experiments measuring friction over a wide range of sliding velocities find that the value of the friction coefficient varies widely: friction is high and behaves according to the rate and state constitutive law during slow sliding, yet markedly weakens as the sliding velocity approaches seismic slip speeds. We introduce a physics-based theory to explain this behavior. Using conventional microphysics of creep, we calculate the velocity and temperature dependence of contact stresses during sliding, including the thermal effects of shear heating. Contacts are assumed to reach a coupled thermal and mechanical steady state, and friction is calculated for steady sliding. Results from theory provide good quantitative agreement with reported experimental results for quartz and granite friction over 11 orders of magnitude in velocity. The new model elucidates the physics of friction and predicts the connection between friction laws to independently determined material parameters. It predicts four frictional regimes as function of slip rate: at slow velocity friction is either velocity strengthening or weakening, depending on material parameters, and follows the rate and state friction law. Differences between surface and volume activation energies are the main control on velocity dependence. At intermediate velocity, for some material parameters, a distinct velocity strengthening regime emerges. At fast sliding, shear heating produces thermal softening of friction. At the fastest sliding, melting causes further weakening. This theory, with its four frictional regimes, fits well previously published experimental results under low temperature and normal stress.

Settling velocities in batch sedimentation

International Nuclear Information System (INIS)

Fricke, A.M.; Thompson, B.E.

1982-10-01

The sedimentation of mixtures containing one and two sizes of spherical particles (44 and 62 μm in diameter) was studied. Radioactive tracing with 57 Co was used to measure the settling velocities. The ratio of the settling velocity U of uniformly sized particles to the velocity predicted to Stokes' law U 0 was correlated to an expression of the form U/U 0 = epsilon/sup α/, where epsilon is the liquid volume fraction and α is an empirical constant, determined experimentally to be 4.85. No effect of viscosity on the ratio U/U 0 was observed as the viscosity of the liquid medium was varied from 1x10 -3 to 5x10 -3 Pa.s. The settling velocities of particles in a bimodal mixture were fit by the same correlation; the ratio U/U 0 was independent of the concentrations of different-sized particles

Statistical scaling of pore-scale Lagrangian velocities in natural porous media.

Science.gov (United States)

Siena, M; Guadagnini, A; Riva, M; Bijeljic, B; Pereira Nunes, J P; Blunt, M J

2014-08-01

We investigate the scaling behavior of sample statistics of pore-scale Lagrangian velocities in two different rock samples, Bentheimer sandstone and Estaillades limestone. The samples are imaged using x-ray computer tomography with micron-scale resolution. The scaling analysis relies on the study of the way qth-order sample structure functions (statistical moments of order q of absolute increments) of Lagrangian velocities depend on separation distances, or lags, traveled along the mean flow direction. In the sandstone block, sample structure functions of all orders exhibit a power-law scaling within a clearly identifiable intermediate range of lags. Sample structure functions associated with the limestone block display two diverse power-law regimes, which we infer to be related to two overlapping spatially correlated structures. In both rocks and for all orders q, we observe linear relationships between logarithmic structure functions of successive orders at all lags (a phenomenon that is typically known as extended power scaling, or extended self-similarity). The scaling behavior of Lagrangian velocities is compared with the one exhibited by porosity and specific surface area, which constitute two key pore-scale geometric observables. The statistical scaling of the local velocity field reflects the behavior of these geometric observables, with the occurrence of power-law-scaling regimes within the same range of lags for sample structure functions of Lagrangian velocity, porosity, and specific surface area.

High velocity properties of the dynamic frictional force between ductile metals

International Nuclear Information System (INIS)

Hammerberg, James Edward; Hollan, Brad L.; Germann, Timothy C.; Ravelo, Ramon J.

2010-01-01

The high velocity properties of the tangential frictional force between ductile metal interfaces seen in large-scale NonEquilibrium Molecular Dynamics (NEMD) simulations are characterized by interesting scaling behavior. In many cases a power law decrease in the frictional force with increasing velocity is observed at high velocities. We discuss the velocity dependence of the high velocity branch of the tangential force in terms of structural transformation and ultimate transition, at the highest velocities, to confined fluid behavior characterized by a critical strain rate. The particular case of an Al/Al interface is discussed.

The Role of Hydrogen Bonding on Laminar Burning Velocity of Hydrous and Anhydrous Ethanol Fuel with Small Addition of n-Heptane

Directory of Open Access Journals (Sweden)

I Made Suarta

2016-01-01

Full Text Available The molecular structure of mixed hydrous and anhydrous ethanol with up to 10% v n-heptane had been studied. The burning velocity was examined in a cylindrical explosion combustion chamber. The result showed that the burning velocity of hydrous ethanol is higher than anhydrous ethanol and n-heptane at stoichiometric, rich, and very rich mixtures. The burning velocity of hydrous ethanol with n-heptane drops drastically compared to the burning velocity of anhydrous ethanol with n-heptane. It is caused by two reasons. Firstly, there was a composition change of azeotropic hydrous ethanol molecules within the mixture of fuel. Secondly, at the same volume the number of ethanol molecules in hydrous ethanol was less than in anhydrous ethanol at the same composition of the n-heptane in the mixture. At the mixture of anhydrous ethanol with n-heptane, the burning velocity decreases proportionally to the addition of the n-heptane composition. The burning velocity is between the velocities of anhydrous ethanol and n-heptane. It shows that the burning velocity of anhydrous ethanol mixed with n-heptane is only influenced by the mixture composition.

Velocity-curvature patterns limit human-robot physical interaction.

Science.gov (United States)

Maurice, Pauline; Huber, Meghan E; Hogan, Neville; Sternad, Dagmar

2018-01-01

Physical human-robot collaboration is becoming more common, both in industrial and service robotics. Cooperative execution of a task requires intuitive and efficient interaction between both actors. For humans, this means being able to predict and adapt to robot movements. Given that natural human movement exhibits several robust features, we examined whether human-robot physical interaction is facilitated when these features are considered in robot control. The present study investigated how humans adapt to biological and non-biological velocity patterns in robot movements. Participants held the end-effector of a robot that traced an elliptic path with either biological (two-thirds power law) or non-biological velocity profiles. Participants were instructed to minimize the force applied on the robot end-effector. Results showed that the applied force was significantly lower when the robot moved with a biological velocity pattern. With extensive practice and enhanced feedback, participants were able to decrease their force when following a non-biological velocity pattern, but never reached forces below those obtained with the 2/3 power law profile. These results suggest that some robust features observed in natural human movements are also a strong preference in guided movements. Therefore, such features should be considered in human-robot physical collaboration.

Cosmological special relativity the large scale structure of space, time and velocity

CERN Document Server

Carmeli, Moshe

1997-01-01

This book deals with special relativity theory and its application to cosmology. It presents Einstein's theory of space and time in detail, and describes the large scale structure of space, time and velocity as a new cosmological special relativity. A cosmological Lorentz-like transformation, which relates events at different cosmic times, is derived and applied. A new law of addition of cosmic times is obtained, and the inflation of the space at the early universe is derived, both from the cosmological transformation. The book will be of interest to cosmologists, astrophysicists, theoretical

Variations and healing of the seismic velocity (Beno Gutenberg Medal Lecture)

Science.gov (United States)

Snieder, Roel

2016-04-01

Scattering of waves leads to a complexity of waveforms that is often seen by seismologists as a nuisance. And indeed, the complicated wave paths of multiple scattered waves makes it difficult to use these waves for imaging. Yet, the long wave paths of multiple scattered waves makes these waves an ideal tool for measuring minute velocity changes. This has led to the development of coda wave interferometry as a tool for measuring small velocity changes in the laboratory and with field data. Combined with the use of noise cross correlations - seismic interferometry - this method is even more useful because it follows for a quasi-continuous measurement of velocity changes. I will show examples of detecting velocity changes in the laboratory, the earth's near surface, and in engineered structures. Perhaps surprisingly, the seismic velocity is not constant at all, and varies with the seasons, temperature, precipitation, as the weather does. In addition, the seismic velocity usually drops as a result of deformation. Most of these changes likely occur in the near surface or the region of deformation, and a drawback of using strongly scattered waves is that it is difficult to localize the spatial area of the velocity change. I will present laboratory measurements that show that a certain spatial localization of the velocity change can be achieved. One of the intriguing observations is that after deformation the seismic velocity recovers logarithmically with time. The reason for this particular time-dependence is the presence of healing mechanisms that operate at different time scales. Since this is feature of many physical systems, the logarithmic healing is a widespread behavior and is akin in its generality to the Gutenberg-Richter law.

Derivation of the Biot-Savart Law from Ampere's Law Using the Displacement Current

Science.gov (United States)

Buschauer, Robert

2013-12-01

The equation describing the magnetic field due to a single, nonrelativistic charged particle moving at constant velocity is often referred to as the "Biot-Savart law for a point charge." Introductory calculus-based physics books usually state this law without proof.2 Advanced texts often present it either without proof or as a special case of a complicated mathematical formalism.3 Either way, little or no physical insight is provided to the student regarding the underlying physics. This paper presents a novel, basic, and transparent derivation of the Biot-Savart law for a point charge based only on Maxwell's displacement current term in Ampere's law. This derivation can serve many pedagogical purposes. For example, it can be used as lecture material at any academic level to obtain the Biot-Savart law for a point charge from simple principles. It can also serve as a practical example of the important fact that a changing electric flux produces a magnetic field.

MEASURING EJECTA VELOCITY IMPROVES TYPE Ia SUPERNOVA DISTANCES

International Nuclear Information System (INIS)

Foley, Ryan J.; Kasen, Daniel

2011-01-01

We use a sample of 121 spectroscopically normal Type Ia supernovae (SNe Ia) to show that their intrinsic color is correlated with their ejecta velocity, as measured from the blueshift of the Si II λ6355 feature near maximum brightness, v SiII . The SN Ia sample was originally used by Wang et al. to show that the relationship between color excess and peak magnitude, which in the absence of intrinsic color differences describes a reddening law, was different for two subsamples split by v SiII (defined as 'Normal' and 'High Velocity'). We verify this result, but find that the two subsamples have the same reddening law when extremely reddened events (E(B - V)>0.35 mag) are excluded. We also show that (1) the High-Velocity subsample is offset by ∼0.06 mag to the red from the Normal subsample in the (B max - V max )-M V plane, (2) the B max - V max cumulative distribution functions of the two subsamples have nearly identical shapes, but the High-Velocity subsample is offset by ∼0.07 mag to the red in B max - V max , and (3) the bluest High-Velocity SNe Ia are ∼0.10 mag redder than the bluest Normal SNe Ia. Together, this evidence indicates a difference in intrinsic color for the subsamples. Accounting for this intrinsic color difference reduces the scatter in Hubble residuals from 0.190 mag to 0.130 mag for SNe Ia with A V ∼ V found in large SN Ia samples. We explain the correlation between ejecta velocity and color as increased line blanketing in the High-Velocity SNe Ia, causing them to become redder. We discuss some implications of this result, and stress the importance of spectroscopy for future SN Ia cosmology surveys, with particular focus on the design of WFIRST.

International Investment Law and EU Law

DEFF Research Database (Denmark)

regional economic integration agreements, International Competition Law, International Investment Regulation, International Monetary Law, International Intellectual Property Protection and International Tax Law. In addition to the regular annual volumes, EYIEL Special Issues routinely address specific...... current topics in International Economic Law. The entry into force of the Lisbon Treaty entails sweeping changes with respect to foreign investment regulation. Most prominently, the Treaty on the Functioning of the European Union (TFEU) now contains in its Article 207 an explicit competence...... for the regulation of foreign direct investment as part of the Common Commercial Policy (CCP) chapter. With this new competence, the EU will become an important actor in the field of international investment politics and law. The new empowerment in the field of international investment law prompts a multitude...

Temperature dynamics and velocity scaling laws for interchange driven, warm ion plasma filaments

DEFF Research Database (Denmark)

Olsen, Jeppe Miki Busk; Madsen, Jens; Nielsen, Anders Henry

2016-01-01

The influence of electron and ion temperature dynamics on the radial convection of isolated structures in magnetically confined plasmas is investigated by means of numerical simulations. It is demonstrated that the maximum radial velocity of these plasma blobs roughly follows the inertial velocity...

Low-velocity Impact Response of a Nanocomposite Beam Using an Analytical Model

Directory of Open Access Journals (Sweden)

Mahdi Heydari Meybodi

Full Text Available AbstractLow-velocity impact of a nanocomposite beam made of glass/epoxy reinforced with multi-wall carbon nanotubes and clay nanoparticles is investigated in this study. Exerting modified rule of mixture (MROM, the mechanical properties of nanocomposite including matrix, nanoparticles or multi-wall carbon nanotubes (MWCNT, and fiber are attained. In order to analyze the low-velocity impact, Euler-Bernoulli beam theory and Hertz's contact law are simultaneously employed to govern the equations of motion. Using Ritz's variational approximation method, a set of nonlinear equations in time domain are obtained, which are solved using a fourth order Runge-Kutta method. The effect of different parameters such as adding nanoparticles or MWCNT's on maximum contact force and energy absorption, stacking sequence, geometrical dimensions (i.e., length, width and height, and initial velocity of the impactor have been studied comprehensively on dynamic behavior of the nanocomposite beam. In addition, the result of analytical model is compared with Finite Element Modeling (FEM.The results reveal that the effect of nanoparticles on energy absorption is more considerable at higher impact energies.

Turbulent structure of thermal plume. Velocity field

International Nuclear Information System (INIS)

Guillou, B.; Brahimi, M.; Doan-kim-son

1986-01-01

An experimental investigation and a numerical study of the dynamics of a turbulent plume rising from a strongly heated source are described. This type of flow is met in thermal effluents (air, vapor) from, e.g., cooling towers of thermal power plants. The mean and fluctuating values of the vertical component of the velocity were determined using a Laser-Doppler anemometer. The measurements allow us to distinguish three regions in the plume-a developing region near the source, an intermediate region, and a self-preserving region. The characteristics of each zone have been determined. In the self-preserving zone, especially, the turbulence level on the axis and the entrainment coefficient are almost twice of the values observed in jets. The numerical model proposed takes into account an important phenomenon, the intermittency, observed in the plume. This model, established with the self-preserving hypothesis, brings out analytical laws. These laws and the predicted velocity profile are in agreement with the experimental evolutions [fr

Regularized lattice Boltzmann model for immiscible two-phase flows with power-law rheology

Science.gov (United States)

Ba, Yan; Wang, Ningning; Liu, Haihu; Li, Qiang; He, Guoqiang

2018-03-01

In this work, a regularized lattice Boltzmann color-gradient model is developed for the simulation of immiscible two-phase flows with power-law rheology. This model is as simple as the Bhatnagar-Gross-Krook (BGK) color-gradient model except that an additional regularization step is introduced prior to the collision step. In the regularization step, the pseudo-inverse method is adopted as an alternative solution for the nonequilibrium part of the total distribution function, and it can be easily extended to other discrete velocity models no matter whether a forcing term is considered or not. The obtained expressions for the nonequilibrium part are merely related to macroscopic variables and velocity gradients that can be evaluated locally. Several numerical examples, including the single-phase and two-phase layered power-law fluid flows between two parallel plates, and the droplet deformation and breakup in a simple shear flow, are conducted to test the capability and accuracy of the proposed color-gradient model. Results show that the present model is more stable and accurate than the BGK color-gradient model for power-law fluids with a wide range of power-law indices. Compared to its multiple-relaxation-time counterpart, the present model can increase the computing efficiency by around 15%, while keeping the same accuracy and stability. Also, the present model is found to be capable of reasonably predicting the critical capillary number of droplet breakup.

Deriving mass-energy equivalence and mass-velocity relation without light

Science.gov (United States)

Dai, Youshan; Dai, Liang

2018-04-01

Relativity requires that a particle's momentum and energy are the same functions of the particle's velocity in all inertial frames. Using the fact that momentum and energy must transform linearly between reference frames, we present a novel derivation of the mass-energy equivalence, namely, the relation that the energy is proportional to the moving mass, with no postulate about the existence of light or its properties. We further prove the mass-velocity relation without relying on momentum and energy conservation or on the Lorentz transformation. It is demonstrated that neither conservation laws nor the Lorentz transformation are necessary to establish those relations, and that those relations have a wider scope of validity than that of the conservation laws and the invariance of the speed of light.

Determination of the propellant combustion law under ballistic experiment conditions

Science.gov (United States)

Ishchenko, A. N.; Diachkovskii, A. S.; Zykova, A. I.; Kasimov, VZ; Samorokova, N. M.

2017-11-01

The main characteristics of ballistic experiment are the maximum pressure in the combustion chamber P max and the projectile velocity at the time of barrel leaving U M. During the work the burning law of the new high-energy fuel was determined in a ballistic experiment. This burning law was used for a parametric study of depending P max and U M from a powder charge mass and a traveling charge at initial temperature of + 20 °C was carried out. The optimal conditions for loading were obtained for improving the muzzle velocity by 14.9 %. Under optimal loading, there is defined the conditions, which is possible to get the greatest value muzzle velocity projectile at pressures up to 600 MPa.

Flow-Field Characteristics of High-Temperature Annular Buoyant Jets and Their Development Laws Influenced by Ventilation System

OpenAIRE

Wang, Yi; Huang, Yanqiu; Liu, Jiaping; Wang, Hai; Liu, Qiuhan

2013-01-01

The flow-field characteristics of high-temperature annular buoyant jets as well as the development laws influenced by ventilation system were studied using numerical methods to eliminate the pollutants effectively in this paper. The development laws of high-temperature annular buoyant jets were analyzed and compared with previous studies, including radial velocity distribution, axial velocity and temperature decay, reattachment position, cross-section diameter, volumetric flow rate, and veloc...

A set-valued force law for spatial Coulomb-Contensou friction

NARCIS (Netherlands)

Leine, R.I.; Glocker, C.

2003-01-01

The aim of this paper is to develop a set-valued contact law for combined spatial Coulomb-Contensou friction, taking into account a normal friction torque (drilling friction) and spin. The set-valued Coulomb-Contensou friction law is derived from a non-smooth velocity pseudo potential. A

The velocity field induced by a helical vortex tube

DEFF Research Database (Denmark)

Fukumoto, Y.; Okulov, Valery

2005-01-01

The influence of finite-core thickness on the velocity field around a vortex tube is addressed. An asymptotic expansion of the Biot-Savart law is made to a higher order in a small parameter, the ratio of core radius to curvature radius, which consists of the velocity field due to lines of monopoles...... and dipoles arranged on the centerline of the tube. The former is associated with an infinitely thin core and is featured by the circulation alone. The distribution of vorticity in the core reflects on the strength of dipole. This result is applied to a helical vortex tube, and the induced velocity due...

Noncommutative nature of the addition of noncollinear velocities in special relativity and the geometric phase method (commemorating the publication centennial of A Sommerfeld's work)

International Nuclear Information System (INIS)

Malykin, Grigorii B

2010-01-01

In 1909, Arnold Sommerfeld used geometric calculations to show that the relativistic addition of two noncollinear velocities on an imaginary-radius sphere is a noncommutative operation. Sommerfeld was the first to use the geometric phase method to calculate the angle between the resulting velocities depending on the order in which they are added. For this, he related the value of this angle to the excess of the spherical triangle formed by the two original velocities and their sum. In 1931, Sommerfeld applied his method to analyze the Thomas precession. (from the history of physics)

Magnetospheric Multiscale (MMS) Observation of Plasma Velocity-Space Cascade Processes

Science.gov (United States)

Parashar, T. N.; Servidio, S.; Matthaeus, W. H.; Chasapis, A.; Perrone, D.; Valentini, F.; Veltri, P.; Gershman, D. J.; Schwartz, S. J.; Giles, B. L.; Fuselier, S. A.; Phan, T.; Burch, J.

2017-12-01

Plasma turbulence is investigated using high-resolution ion velocity distributions, measured by theMagnetospheric Multiscale Mission (MMS) in the Earth's magnetosheath. The particle distributionmanifests large fluctuations, suggesting a cascade-like process in velocity space, invoked by theoristsfor many years. This complex velocity space structure is investigated using a three-dimensional Hermitetransform that reveals a power law distribution of moments. A Kolmogorov approach leads directlyto a range of predictions for this phase-space cascade. The scaling theory is in agreement withobservations, suggesting a new path for the study of plasma turbulence in weakly collisional spaceand astrophysical plasmas.

Ohm's law in turbulent plasmas and beta limitations by anomalous diffusion

International Nuclear Information System (INIS)

Borrass, K.

1978-01-01

For axisymmetric diffusive equilibria a condition is derived by means of a generalized Ohm's law. It relates some effective outward particle flux to the toroidal current density. An approximate version of it requires that the corresponding effective diffusion velocity Vsub(D)sup(*) must not exceed the poloidal magnetic diffusion velocity Vsub(m). The simple version of Ohm's law as used in transport calculations only applies if Vsub(D)sup(*)<< Vsub(m). A preliminary discussion is performed for the case of anomalous diffusion due to trapped particle instabilities. (author)

The origin of the Vogel-Fulcher law near the liquid-glass transition

International Nuclear Information System (INIS)

Kitamura, T.

1999-01-01

Taking into account the scattering processes due to random eigenfrequencies and random hopping matrices, we calculate the correlation functions of density fluctuations associated with the particle-hole pairs in the intraband and interband. The correlation functions for the intraband yield sound velocity (proportional to the mean atomic velocity) and diffusion (equal to the relaxation time of atoms multiplied by square of the sound velocity). Those for the interband yield phonons and viscosity (equal to the Maxwell relaxation time multiplied by square of the phonon velocity). The relaxation times and the transport coefficients are governed by the Vogel-Fulcher law through the hopping matrices. Phonons exist in both phases, but sound disappears below the freezing point. The Stokes' law between diffusion and viscosity holds at higher temperatures, but breaks at lower temperatures. (Copyright (c) 1999 Elsevier Science B.V.., Amsterdam. All rights reserved.)

International law

CERN Document Server

Shaw, Malcolm N

2017-01-01

International Law is the definitive and authoritative text on the subject, offering Shaw's unbeatable combination of clarity of expression and academic rigour and ensuring both understanding and critical analysis in an engaging and authoritative style. Encompassing the leading principles, practice and cases, and retaining and developing the detailed references which encourage and assist the reader in further study, this new edition motivates and challenges students and professionals while remaining accessible and engaging. Fully updated to reflect recent case law and treaty developments, this edition contains an expanded treatment of the relationship between international and domestic law, the principles of international humanitarian law, and international criminal law alongside additional material on international economic law.

The solidification velocity of nickel and titanium alloys

Science.gov (United States)

Altgilbers, Alex Sho

2002-09-01

The solidification velocity of several Ni-Ti, Ni-Sn, Ni-Si, Ti-Al and Ti-Ni alloys were measured as a function of undercooling. From these results, a model for alloy solidification was developed that can be used to predict the solidification velocity as a function of undercooling more accurately. During this investigation a phenomenon was observed in the solidification velocity that is a direct result of the addition of the various alloying elements to nickel and titanium. The additions of the alloying elements resulted in an additional solidification velocity plateau at intermediate undercoolings. Past work has shown a solidification velocity plateau at high undercoolings can be attributed to residual oxygen. It is shown that a logistic growth model is a more accurate model for predicting the solidification of alloys. Additionally, a numerical model is developed from simple description of the effect of solute on the solidification velocity, which utilizes a Boltzmann logistic function to predict the plateaus that occur at intermediate undercoolings.

Kinetic Theory Derivation of the Adiabatic Law for Ideal Gases.

Science.gov (United States)

Sobel, Michael I.

1980-01-01

Discusses how the adiabatic law for ideal gases can be derived from the assumption of a Maxwell-Boltzmann (or any other) distribution of velocities--in contrast to the usual derivations from thermodynamics alone, and the higher-order effect that leads to one-body viscosity. An elementary derivation of the adiabatic law is given. (Author/DS)

Various Paths to Faraday's Law

Science.gov (United States)

Redzic, Dragan V.

2008-01-01

In a recent note, the author presented a derivation of Faraday's law of electromagnetic induction for a closed filamentary circuit C(t) which is moving at relativistic velocities and also changing its shape as it moves via the magnetic vector potential. Recently, Kholmetskii et al, while correcting an error in an equation, showed that it can be…

Application of Vectors to Relative Velocity

Science.gov (United States)

Tin-Lam, Toh

2004-01-01

The topic 'relative velocity' has recently been introduced into the Cambridge Ordinary Level Additional Mathematics syllabus under the application of Vectors. In this note, the results of relative velocity and the 'reduction to rest' technique of teaching relative velocity are derived mathematically from vector algebra, in the hope of providing…

Power Laws are Disguised Boltzmann Laws

Science.gov (United States)

Richmond, Peter; Solomon, Sorin

Using a previously introduced model on generalized Lotka-Volterra dynamics together with some recent results for the solution of generalized Langevin equations, we derive analytically the equilibrium mean field solution for the probability distribution of wealth and show that it has two characteristic regimes. For large values of wealth, it takes the form of a Pareto style power law. For small values of wealth, wGeneralized Lotka-Volterra type of stochastic dynamics. The power law that arises in the distribution function is identified with new additional logarithmic terms in the familiar Boltzmann distribution function for the system. These are a direct consequence of the multiplicative stochastic dynamics and are absent for the usual additive stochastic processes.

Experimental investigation on the spray characteristics of power-law fluid in a swirl injector

Energy Technology Data Exchange (ETDEWEB)

Bai, Fuqiang; Chen, Shixing; Guo, Jinpeng; Jiao, Kui; Du, Qing [State Key Laboratory of Engines, Tianjin University, Tianjin, 300072 (China); Chang, Qing, E-mail: duqing@tju.edu.cn [Wuxi Fuel Injection Equipment Research Institute, China FAW CO., Wuxi, 214063 (China)

2017-06-15

High-speed photography and 3D phase Doppler methods are used to obtain the swirl jet images, 3D velocities and size distribution of different droplets (including deionized water and two kinds of power-law fluid). For the power-law fluids, a short circular jet is formed after the nozzle exit at low pressure. Along the X direction, the distributions of axial velocity w and Sauter mean diameter (SMD) are symmetrical and increase from the center to both sides. The effect of injection pressure on the radial velocity u is not obvious. Along the Z axis, the absolute value of 3D velocities decreases to some extent with droplets moving downstream. The SMD decreases apparently with the increment of the distance along the Z axis at 1.0 MPa. (paper)

Neutron Star Population Dynamics. II. Three-dimensional Space Velocities of Young Pulsars

Science.gov (United States)

Cordes, J. M.; Chernoff, David F.

1998-09-01

We use astrometric, distance, and spindown data on pulsars to (1) estimate three-dimensional velocity components, birth distances from the Galactic plane, and ages of individual objects; (2) determine the distribution of space velocities and the scale height of pulsar progenitors; (3) test spindown laws for pulsars; (4) test for correlations between space velocities and other pulsar parameters; and (5) place empirical requirements on mechanisms than can produce high-velocity neutron stars. Our approach incorporates measurement errors, uncertainties in distances, deceleration in the Galactic potential, and differential Galactic rotation. We focus on a sample of proper motion measurements of young (case-by-case basis assuming that the actual age equals the conventional spindown age for a braking index n = 3, no torque decay, and birth periods much shorter than present-day periods. Every sample member could have originated within 0.3 kpc of the Galactic plane while still having reasonable present-day peculiar radial velocities. For the 49 object sample, the scale height of the progenitors is ~0.13 kpc, and the three-dimensional velocities are distributed in two components with characteristic speeds of 175+19-24 km s-1 and 700+300-132 km s-1, representing ~86% and ~14% of the population, respectively. The sample velocities are inconsistent with a single-component Gaussian model and are well described by a two-component Gaussian model but do not require models of additional complexity. From the best-fit distribution, we estimate that about 20% of the known pulsars will escape the Galaxy, assuming an escape speed of 500 km s-1. The best-fit, dual-component model, if augmented by an additional, low-velocity (The best three-component models do not show a preference for filling in the probability distribution at speeds intermediate to 175 and 700 km s-1 but are nearly degenerate with the best two-component models. We estimate that the high-velocity tail (>1000 km s-1) may

The sound velocity in an equilibrium hadron gas

OpenAIRE

Prorok, Dariusz; Turko, Ludwik

2001-01-01

We calculate the velocity of sound in an ideal gas of massive hadrons with non-vanishing baryon number. The gas is in thermal and chemical equilibrium. Also we show that the temperature dependence $T(\\tau) \\cong T_{0} \\cdot ({\\tau_{0} \\over \\tau})^{c_{s}^{2}}$ is approximately valid, when the gas expands longitudinally according to the Bjorken law.

Velocity dispersion profiles of clusters of galaxies

International Nuclear Information System (INIS)

Struble, M.F.

1979-01-01

Velocity dispersion as a function of radius, called sigma/sub ls/ profiles, is presented for 13 clusters of galaxies having > or =30 radial velocities from both published and unpublished lists. A list of probable new members and possible outlying members for these clusters is also given. chi 2 and Kolmogoroff--Smirnoff one-sample tests for the goodness of fit of power laws to portions of the profiles indicate two significant structures in some profiles: (1) a local minimum corresponding to the local minimum noted in surface density or surface brightness profiles, and (2) a decrease in sigma/sub ls/ toward the cores. Both of these features are discussed in terms of a comparison with Wielen's N-body simulations. The sigma/sub ls/ profiles are placed in a new classification scheme which lends itself to interpreting clusters in a dynamical age sequence. The velocity field of galaxies at large distances from cluster centers is also discussed

Low-Velocity Impact Behavior of Sandwich Structures with Additively Manufactured Polymer Lattice Cores

Science.gov (United States)

Turner, Andrew J.; Al Rifaie, Mohammed; Mian, Ahsan; Srinivasan, Raghavan

2018-05-01

Sandwich panel structures are widely used in aerospace, marine, and automotive applications because of their high flexural stiffness, strength-to-weight ratio, good vibration damping, and low through-thickness thermal conductivity. These structures consist of solid face sheets and low-density cellular core structures, which are traditionally based upon honeycomb folded-sheet topologies. The recent advances in additive manufacturing (AM) or 3D printing process allow lattice core configurations to be designed with improved mechanical properties. In this work, the sandwich core is comprised of lattice truss structures (LTS). Two different LTS designs are 3D-printed using acrylonitrile butadiene styrene (ABS) and are tested under low-velocity impact loads. The absorption energy and the failure mechanisms of lattice cells under such loads are investigated. The differences in energy-absorption capabilities are captured by integrating the load-displacement curve found from the impact response. It is observed that selective placement of vertical support struts in the unit-cell results in an increase in the absorption energy of the sandwich panels.

Low-Velocity Impact Behavior of Sandwich Structures with Additively Manufactured Polymer Lattice Cores

Science.gov (United States)

Turner, Andrew J.; Al Rifaie, Mohammed; Mian, Ahsan; Srinivasan, Raghavan

2018-04-01

Sandwich panel structures are widely used in aerospace, marine, and automotive applications because of their high flexural stiffness, strength-to-weight ratio, good vibration damping, and low through-thickness thermal conductivity. These structures consist of solid face sheets and low-density cellular core structures, which are traditionally based upon honeycomb folded-sheet topologies. The recent advances in additive manufacturing (AM) or 3D printing process allow lattice core configurations to be designed with improved mechanical properties. In this work, the sandwich core is comprised of lattice truss structures (LTS). Two different LTS designs are 3D-printed using acrylonitrile butadiene styrene (ABS) and are tested under low-velocity impact loads. The absorption energy and the failure mechanisms of lattice cells under such loads are investigated. The differences in energy-absorption capabilities are captured by integrating the load-displacement curve found from the impact response. It is observed that selective placement of vertical support struts in the unit-cell results in an increase in the absorption energy of the sandwich panels.

Consideration of some difficulties in migration velocity analysis; Migration velocity analysis no shomondai ni kansuru kento

Energy Technology Data Exchange (ETDEWEB)

Akama, K [Japan National Oil Corp., Tokyo (Japan). Technology Research Center; Matsuoka, T [Japan Petroleum Exploration Corp., Tokyo (Japan)

1997-10-22

Concerning migration velocity analysis in the seismic exploration method, two typical techniques, out of velocity analysis techniques using residual moveout in the CIP gather, are verified. Deregowski`s method uses pre-stacking deep-level migration records for velocity analysis to obtain velocities free of spatial inconsistency and not dependent on the velocity structure. This method is very like the conventional DMO velocity analysis method and is easy to understand intuitively. In this method, however, error is apt to be aggravated in the process of obtaining the depth-sector velocity from the time-RMS velocity. Al-Yahya`s method formulates the moveout residual in the CIP gather. This assumes horizontal stratification and a small residual velocity, however, and fails to guarantee convergence in the case of a steep structure or a grave model error. In the updating of the velocity model, in addition, it has to maintain required accuracy and, at the same time, incorporate smoothing to ensure not to deteriorate high convergence. 2 refs., 5 figs.

Analysis of the velocity distribution in different types of ventilation system ducts

Science.gov (United States)

Peszyński, Kazimierz; Olszewski, Lukasz; Smyk, Emil; Perczyński, Daniel

2018-06-01

The paper presents the results obtained during the preliminary studies of circular and rectangular ducts before testing the properties elements (elbows, tees, etc.)of rectangular with rounded corners ducts. The fundamental problem of the studies was to determine the flow rate in the ventilation duct. Due to the size of the channel it was decided to determine the flow rate based on the integration of flow velocity over the considered cross-section. This method requires knowledge of the velocity distribution in the cross section. Approximation of the measured actual profile by the classic and modified Prandtl power-law velocity profile was analysed.

Velocity Distributions in Inelastic Granular Gases with Continuous Size Distributions

International Nuclear Information System (INIS)

Li Rui; Li Zhi-Hao; Zhang Duan-Ming

2011-01-01

We study by numerical simulation the property of velocity distributions of granular gases with a power-law size distribution, driven by uniform heating and boundary heating. It is found that the form of velocity distribution is primarily controlled by the restitution coefficient η and q, the ratio between the average number of heatings and the average number of collisions in the system. Furthermore, we show that uniform and boundary heating can be understood as different limits of q, with q ≫ 1 and q ≤ 1, respectively. (general)

Additive scaling law for structural organization of chromatin in chicken erythrocyte nuclei

Science.gov (United States)

Iashina, E. G.; Velichko, E. V.; Filatov, M. V.; Bouwman, W. G.; Duif, C. P.; Brulet, A.; Grigoriev, S. V.

2017-07-01

Small-angle neutron scattering (SANS) on nuclei of chicken erythrocytes demonstrates the cubic dependence of the scattering intensity Q-3 in the range of momentum transfer Q ∈10-3-10-2nm-1 . Independent spin-echo SANS measurements give the spin-echo function, which is well described by the exponential law in a range of sizes (3 ×102) -(3 ×104) nm. Both experimental dependences reflect the nature of the structural organization of chromatin in the nucleus of a living cell, which corresponds to the correlation function γ (r )=ln(ξ /r ) for r <ξ , where ξ =(3.69 ±0.07 ) ×103 nm, the size of the nucleus. It has the specific scaling property of the logarithmic fractal γ (r /a )=γ (r )+ln(a ), i.e., the scaling down by a gives an additive constant to the correlation function, which distinguishes it from the mass fractal, which is characterized by multiplicative constant.

Spectral derivation of the classic laws of wall-bounded turbulent flows.

Science.gov (United States)

Gioia, Gustavo; Chakraborty, Pinaki

2017-08-01

We show that the classic laws of the mean-velocity profiles (MVPs) of wall-bounded turbulent flows-the 'law of the wall,' the 'defect law' and the 'log law'-can be predicated on a sufficient condition with no manifest ties to the MVPs, namely that viscosity and finite turbulent domains have a depressive effect on the spectrum of turbulent energy. We also show that this sufficient condition is consistent with empirical data on the spectrum and may be deemed a general property of the energetics of wall turbulence. Our findings shed new light on the physical origin of the classic laws and their immediate offshoot, Prandtl's theory of turbulent friction.

Dark Energy and the Hubble Law

Science.gov (United States)

Chernin, A. D.; Dolgachev, V. P.; Domozhilova, L. M.

The Big Bang predicted by Friedmann could not be empirically discovered in the 1920th, since global cosmological distances (more than 300-1000 Mpc) were not available for observations at that time. Lemaitre and Hubble studied receding motions of galaxies at local distances of less than 20-30 Mpc and found that the motions followed the (nearly) linear velocity-distance relation, known now as Hubble's law. For decades, the real nature of this phenomenon has remained a mystery, in Sandage's words. After the discovery of dark energy, it was suggested that the dynamics of local expansion flows is dominated by omnipresent dark energy, and it is the dark energy antigravity that is able to introduce the linear velocity-distance relation to the flows. It implies that Hubble's law observed at local distances was in fact the first observational manifestation of dark energy. If this is the case, the commonly accepted criteria of scientific discovery lead to the conclusion: In 1927, Lemaitre discovered dark energy and Hubble confirmed this in 1929.

Crater ejecta scaling laws: fundamental forms based on dimensional analysis

International Nuclear Information System (INIS)

Housen, K.R.; Schmidt, R.M.; Holsapple, K.A.

1983-01-01

A model of crater ejecta is constructed using dimensional analysis and a recently developed theory of energy and momentum coupling in cratering events. General relations are derived that provide a rationale for scaling laboratory measurements of ejecta to larger events. Specific expressions are presented for ejection velocities and ejecta blanket profiles in two limiting regimes of crater formation: the so-called gravity and strength regimes. In the gravity regime, ejectra velocities at geometrically similar launch points within craters vary as the square root of the product of crater radius and gravity. This relation implies geometric similarity of ejecta blankets. That is, the thickness of an ejecta blanket as a function of distance from the crater center is the same for all sizes of craters if the thickness and range are expressed in terms of crater radii. In the strength regime, ejecta velocities are independent of crater size. Consequently, ejecta blankets are not geometrically similar in this regime. For points away from the crater rim the expressions for ejecta velocities and thickness take the form of power laws. The exponents in these power laws are functions of an exponent, α, that appears in crater radius scaling relations. Thus experimental studies of the dependence of crater radius on impact conditions determine scaling relations for ejecta. Predicted ejection velocities and ejecta-blanket profiles, based on measured values of α, are compared to existing measurements of velocities and debris profiles

Roughage digestibility and velocity of its passage through the alimentary tract of wethers as affected by mineral additives and gamma irradiation

International Nuclear Information System (INIS)

Sandev, S.

1976-01-01

Balance trials conducted with wethers established the apparent digestibility of roughage and the velocity of its passage through the alimentary tract. All rations amounted to 1000 g daily. Studied was the influence of 4% bentonit supplementation of the ration of ground meadow hay and of 7% bentonit to ration of 60%. ground lucerne hay and 40% concentrate. 4% bentonit supplementation did not affect the velocity of passage through the alimentary tract, but 7% bentonit supplementation depressed apparent digestibility. The addition of 12 g MgO and 5 NaHCO 3 to a ration of 1000 g finely ground meadow hay was studied under the same conditions. There were no considerable changes in digestibility and velocity of passage. Acetic acid molar ratio was slightly enhanced. The influence of gamma irradiation on pellets of 85% meadow hay and 15% concentrate was studied also under the same conditions. The irradiation dose was 4 Mr. Crude fat digestibility went up and that of crude fiber - dropped. However, organic matter digestibility was not affected. These data resemble the results obtained with complete roughage ration mixtures following pelleting. (author)

Influence of slip velocity in Herschel-Bulkley fluid flow between parallel plates - A mathematical study

International Nuclear Information System (INIS)

Sankar, D. S.; Lee, U Sik

2016-01-01

This theoretical study investigates three types of basic flows of viscous incompressible Herschel-Bulkley fluid such as (i) plane Couette flow, (ii) Poiseuille flow and (iii) generalized Couette flow with slip velocity at the boundary. The analytic solutions to the nonlinear boundary value problems have been obtained. The effects of various physical parameters on the velocity, flow rate, wall shear stress and frictional resistance to flow are analyzed through appropriate graphs. It is observed that in plane Poiseuille flow and generalized Couette flow, the velocity and flow rate of the fluid increase considerably with the increase of the slip parameter, power law index, pressure gradient. The fluid velocity is significantly higher in plane Poiseuille flow than in plane Couette flow. The wall shear stress and frictional resistance to flow decrease considerably with the increase of the power law index and increase significantly with the increase of the yield stress of the fluid. The wall shear stress and frictional resistance to flow are considerably higher in plane Poiseuille flow than in generalized Couette flow.

Flocculation and Settling Velocity Estimates for Reservoir Sedimentation Analysis

Science.gov (United States)

2016-02-01

viscosity ). Stokes’ law is commonly used to describe settling velocity of a single particle and is applicable when the particle Reynolds number (Rep...fluid viscosity , and ν is kinematic viscosity . Several researchers recognize that large, fast-settling particles disobey the laminar boundary...interparticle attraction caused by electrostatic and physiochemical forces. These properties give clays their stickiness and control essential

Theoretical Research Progress in High-Velocity/Hypervelocity Impact on Semi-Infinite Targets

Directory of Open Access Journals (Sweden)

Yunhou Sun

2015-01-01

Full Text Available With the hypervelocity kinetic weapon and hypersonic cruise missiles research projects being carried out, the damage mechanism for high-velocity/hypervelocity projectile impact on semi-infinite targets has become the research keystone in impact dynamics. Theoretical research progress in high-velocity/hypervelocity impact on semi-infinite targets was reviewed in this paper. The evaluation methods for critical velocity of high-velocity and hypervelocity impact were summarized. The crater shape, crater scaling laws and empirical formulae, and simplified analysis models of crater parameters for spherical projectiles impact on semi-infinite targets were reviewed, so were the long rod penetration state differentiation, penetration depth calculation models for the semifluid, and deformed long rod projectiles. Finally, some research proposals were given for further study.

Modification of Turbulent Pipe Flow Equations to Estimate the Vertical Velocity Profiles Under Woody Debris Jams

Science.gov (United States)

Cervania, A.; Knack, I. M. W.

2017-12-01

The presence of woody debris (WD) jams in rivers and streams increases the risk of backwater flooding and reduces the navigability of a channel, but adds fish and macroinvertebrate habitat to the stream. When designing river engineering projects engineers use hydraulic models to predict flow behavior around these obstructions. However, the complexities of flow through and beneath WD jams are still poorly understood. By increasing the ability to predict flow behavior around WD jams, landowners and engineers are empowered to develop sustainable practices regarding the removal or placement of WD in rivers and flood plains to balance the desirable and undesirable effects to society and the environment. The objective of this study is to address some of this knowledge gap by developing a method to estimate the vertical velocity profile of flow under WD jams. When flow passes under WD jams, it becomes affected by roughness elements on all sides, similar to turbulent flows in pipe systems. Therefore, the method was developed using equations that define the velocity profiles of turbulent pipe flows: the law of the wall, the logarithmic law, and the velocity defect law. Flume simulations of WD jams were conducted and the vertical velocity profiles were measured along the centerline. A calculated velocity profile was fit to the measured profile through the calibration of eight parameters. An optimal value or range of values have been determined for several of these parameters using cross-validation techniques. The results indicate there may be some promise to using this method in hydraulic models.

Clear and Measurable Signature of Modified Gravity in the Galaxy Velocity Field

Science.gov (United States)

Hellwing, Wojciech A.; Barreira, Alexandre; Frenk, Carlos S.; Li, Baojiu; Cole, Shaun

2014-06-01

The velocity field of dark matter and galaxies reflects the continued action of gravity throughout cosmic history. We show that the low-order moments of the pairwise velocity distribution v12 are a powerful diagnostic of the laws of gravity on cosmological scales. In particular, the projected line-of-sight galaxy pairwise velocity dispersion σ12(r) is very sensitive to the presence of modified gravity. Using a set of high-resolution N-body simulations, we compute the pairwise velocity distribution and its projected line-of-sight dispersion for a class of modified gravity theories: the chameleon f(R) gravity and Galileon gravity (cubic and quartic). The velocities of dark matter halos with a wide range of masses would exhibit deviations from general relativity at the (5-10)σ level. We examine strategies for detecting these deviations in galaxy redshift and peculiar velocity surveys. If detected, this signature would be a "smoking gun" for modified gravity.

The universal sound velocity formula for the strongly interacting unitary Fermi gas

International Nuclear Information System (INIS)

Liu Ke; Chen Ji-Sheng

2011-01-01

Due to the scale invariance, the thermodynamic laws of strongly interacting limit unitary Fermi gas can be similar to those of non-interacting ideal gas. For example, the virial theorem between pressure and energy density of the ideal gas P = 2E/3V is still satisfied by the unitary Fermi gas. This paper analyses the sound velocity of unitary Fermi gases with the quasi-linear approximation. For comparison, the sound velocities for the ideal Boltzmann, Bose and Fermi gas are also given. Quite interestingly, the sound velocity formula for the ideal non-interacting gas is found to be satisfied by the unitary Fermi gas in different temperature regions. (general)

Analysis of the velocity distribution in different types of ventilation system ducts

Directory of Open Access Journals (Sweden)

Peszyński Kazimierz

2018-01-01

Full Text Available The paper presents the results obtained during the preliminary studies of circular and rectangular ducts before testing the properties elements (elbows, tees, etc.of rectangular with rounded corners ducts. The fundamental problem of the studies was to determine the flow rate in the ventilation duct. Due to the size of the channel it was decided to determine the flow rate based on the integration of flow velocity over the considered cross-section. This method requires knowledge of the velocity distribution in the cross section. Approximation of the measured actual profile by the classic and modified Prandtl power-law velocity profile was analysed.

Velocity Regulation in Switched Reluctance Motors under Magnetic Flux Saturation Conditions

Directory of Open Access Journals (Sweden)

Victor M. Hernández-Guzmán

2018-01-01

Full Text Available We propose a controller for velocity regulation in switched reluctance motors under magnetic flux saturation conditions. Both hysteresis and proportional control are employed in the internal electric current loops. A classical PI velocity controller is employed in the external loop. Our control law is the simplest one proposed in the literature but provided with a formal stability proof. We prove that the state is bounded having an ultimate bound which can be rendered arbitrarily small by a suitable selection of controller gains. Furthermore, this result stands when starting from any initial condition within a radius which can be arbitrarily enlarged using suitable controller gains. We present a simulation study where even convergence to zero of velocity error is observed as well as a good performance when regulating velocity in the presence of unknown step changes in external torque disturbances.

Dust-acoustic waves and stability in the permeating dusty plasma. II. Power-law distributions

International Nuclear Information System (INIS)

Gong Jingyu; Du Jiulin; Liu Zhipeng

2012-01-01

The dust-acoustic waves and the stability theory for the permeating dusty plasma with power-law distributions are studied by using nonextensive q-statistics. In two limiting physical cases, when the thermal velocity of the flowing dusty plasma is much larger than, and much smaller than the phase velocity of the waves, we derived the dust-acoustic wave frequency, the instability growth rate, and the instability critical flowing velocity. As compared with the formulae obtained in part I [Gong et al., Phys. Plasmas 19, 043704 (2012)], all formulae of the present cases and the resulting plasma characteristics are q-dependent, and the power-law distribution of each plasma component of the permeating dusty plasma has a different q-parameter and thus has a different nonextensive effect. Further, we make numerical analyses of an example that a cometary plasma tail is passing through the interplanetary space dusty plasma and we show that these power-law distributions have significant effects on the plasma characteristics of this kind of plasma environment.

Estimating the Wet-Rock P-Wave Velocity from the Dry-Rock P-Wave Velocity for Pyroclastic Rocks

Science.gov (United States)

Kahraman, Sair; Fener, Mustafa; Kilic, Cumhur Ozcan

2017-07-01

Seismic methods are widely used for the geotechnical investigations in volcanic areas or for the determination of the engineering properties of pyroclastic rocks in laboratory. Therefore, developing a relation between the wet- and dry-rock P-wave velocities will be helpful for engineers when evaluating the formation characteristics of pyroclastic rocks. To investigate the predictability of the wet-rock P-wave velocity from the dry-rock P-wave velocity for pyroclastic rocks P-wave velocity measurements were conducted on 27 different pyroclastic rocks. In addition, dry-rock S-wave velocity measurements were conducted. The test results were modeled using Gassmann's and Wood's theories and it was seen that estimates for saturated P-wave velocity from the theories fit well measured data. For samples having values of less and greater than 20%, practical equations were derived for reliably estimating wet-rock P-wave velocity as function of dry-rock P-wave velocity.

Investigation of Velocity Distribution in Open Channel Flows Based on Conditional Average of Turbulent Structures

Directory of Open Access Journals (Sweden)

Yu Han

2017-01-01

Full Text Available We report the development of a new analytical model similar to the Reynolds-averaged Navier-Stokes equations to determine the distribution of streamwise velocity by considering the bursting phenomenon. It is found that, in two-dimensional (2D flows, the underlying mechanism of the wake law in 2D uniform flow is actually a result of up/down events. A special experiment was conducted to examine the newly derived analytical model, and good agreement is achieved between the experimental data in the inner region and the model’s prediction. The obtained experimental data were also used to examine the DML-Law (dip-modified-log-law, MLW-Law (modified-log-wake law, and CML-Law (Cole’s wake law, and the agreement is not very satisfactory in the outer region.

Simple Model for Simulating Characteristics of River Flow Velocity in Large Scale

Directory of Open Access Journals (Sweden)

Husin Alatas

2015-01-01

Full Text Available We propose a simple computer based phenomenological model to simulate the characteristics of river flow velocity in large scale. We use shuttle radar tomography mission based digital elevation model in grid form to define the terrain of catchment area. The model relies on mass-momentum conservation law and modified equation of motion of falling body in inclined plane. We assume inelastic collision occurs at every junction of two river branches to describe the dynamics of merged flow velocity.

Chronicle 1998, Administrative law/Droit administratif

NARCIS (Netherlands)

Bok, A.J.

1999-01-01

In this contribution, two recent developments in Dutch administrative law are discussed. The codification of administrative law in a General Administrative Law Act (1994) has contributed much to this field of law, but has also caused additional legal complications for the administration. In 1997 the

Seepage Characteristics Study on Power-Law Fluid in Fractal Porous Media

Directory of Open Access Journals (Sweden)

Meijuan Yun

2014-01-01

Full Text Available We present fractal models for the flow rate, velocity, effective viscosity, apparent viscosity, and effective permeability for power-law fluid based on the fractal properties of porous media. The proposed expressions realize the quantitative description to the relation between the properties of the power-law fluid and the parameters of the microstructure of the porous media. The model predictions are compared with related data and good agreement between them is found. The analytical expressions will contribute to the revealing of physical principles for the power-law fluid flow in porous media.

Hierarchical random additive process and logarithmic scaling of generalized high order, two-point correlations in turbulent boundary layer flow

Science.gov (United States)

Yang, X. I. A.; Marusic, I.; Meneveau, C.

2016-06-01

Townsend [Townsend, The Structure of Turbulent Shear Flow (Cambridge University Press, Cambridge, UK, 1976)] hypothesized that the logarithmic region in high-Reynolds-number wall-bounded flows consists of space-filling, self-similar attached eddies. Invoking this hypothesis, we express streamwise velocity fluctuations in the inertial layer in high-Reynolds-number wall-bounded flows as a hierarchical random additive process (HRAP): uz+=∑i=1Nzai . Here u is the streamwise velocity fluctuation, + indicates normalization in wall units, z is the wall normal distance, and ai's are independently, identically distributed random additives, each of which is associated with an attached eddy in the wall-attached hierarchy. The number of random additives is Nz˜ln(δ /z ) where δ is the boundary layer thickness and ln is natural log. Due to its simplified structure, such a process leads to predictions of the scaling behaviors for various turbulence statistics in the logarithmic layer. Besides reproducing known logarithmic scaling of moments, structure functions, and correlation function [" close="]3/2 uz(x ) uz(x +r ) >, new logarithmic laws in two-point statistics such as uz4(x ) > 1 /2, 1/3, etc. can be derived using the HRAP formalism. Supporting empirical evidence for the logarithmic scaling in such statistics is found from the Melbourne High Reynolds Number Boundary Layer Wind Tunnel measurements. We also show that, at high Reynolds numbers, the above mentioned new logarithmic laws can be derived by assuming the arrival of an attached eddy at a generic point in the flow field to be a Poisson process [Woodcock and Marusic, Phys. Fluids 27, 015104 (2015), 10.1063/1.4905301]. Taken together, the results provide new evidence supporting the essential ingredients of the attached eddy hypothesis to describe streamwise velocity fluctuations of large, momentum transporting eddies in wall-bounded turbulence, while observed deviations suggest the need for further extensions of the

Charging conditions research to increase the initial projected velocity at different initial charge temperatures

Science.gov (United States)

Ishchenko, Aleksandr; Burkin, Viktor; Kasimov, Vladimir; Samorokova, Nina; Zykova, Angelica; Diachkovskii, Alexei

2017-11-01

The problems of the defense industry occupy the most important place in the constantly developing modern world. The daily development of defense technology does not stop, nor do studies on internal ballistics. The scientists of the whole world are faced with the task of managing the main characteristics of a ballistic experiment. The main characteristics of the ballistic experiment are the maximum pressure in the combustion chamber Pmax and the projected velocity at the time of barrel leaving UM. During the work the combustion law of the new high-energy fuel was determined in a ballistic experiment for different initial temperatures. This combustion law was used for a parametric study of depending Pmax and UM from a powder charge mass and a traveling charge was carried out. The optimal conditions for loading were obtained for improving the initial velocity at pressures up to 600 MPa for different initial temperatures. In this paper, one of the most promising schemes of throwing is considered, as well as a method for increasing the muzzle velocity of a projected element to 3317 m/s.

Dentistry and criminal law.

Science.gov (United States)

Khoury, B S; Khoury, J N

2017-09-01

Criminal law in dentistry, as shaped and moulded by the prevailing views of society, defines what is or is not socially acceptable. It applies in both personal and professional contexts with the intended consequence of protecting the public from unacceptable conduct and potential imbalances of power. At its centre, a patient's consent plays a pivotal role in transforming unlawful conduct into lawful conduct. This literature review considers the current law and the trend of utilizing criminal law in addition to non-criminal law alternatives of reprimanding clinicians for failure to achieve consent in the course of dental practice. Dentists must appreciate this change and the prosecuting authority's increasing willingness to resort to criminal law. © 2017 Australian Dental Association.

Velocity Segregation and Systematic Biases In Velocity Dispersion Estimates with the SPT-GMOS Spectroscopic Survey

Science.gov (United States)

Bayliss, Matthew. B.; Zengo, Kyle; Ruel, Jonathan; Benson, Bradford A.; Bleem, Lindsey E.; Bocquet, Sebastian; Bulbul, Esra; Brodwin, Mark; Capasso, Raffaella; Chiu, I.-non; McDonald, Michael; Rapetti, David; Saro, Alex; Stalder, Brian; Stark, Antony A.; Strazzullo, Veronica; Stubbs, Christopher W.; Zenteno, Alfredo

2017-03-01

The velocity distribution of galaxies in clusters is not universal; rather, galaxies are segregated according to their spectral type and relative luminosity. We examine the velocity distributions of different populations of galaxies within 89 Sunyaev Zel’dovich (SZ) selected galaxy clusters spanning 0.28GMOS spectroscopic survey, supplemented by additional published spectroscopy, resulting in a final spectroscopic sample of 4148 galaxy spectra—2868 cluster members. The velocity dispersion of star-forming cluster galaxies is 17 ± 4% greater than that of passive cluster galaxies, and the velocity dispersion of bright (m< {m}* -0.5) cluster galaxies is 11 ± 4% lower than the velocity dispersion of our total member population. We find good agreement with simulations regarding the shape of the relationship between the measured velocity dispersion and the fraction of passive versus star-forming galaxies used to measure it, but we find a small offset between this relationship as measured in data and simulations, which suggests that our dispersions are systematically low by as much as 3% relative to simulations. We argue that this offset could be interpreted as a measurement of the effective velocity bias that describes the ratio of our observed velocity dispersions and the intrinsic velocity dispersion of dark matter particles in a published simulation result. Measuring velocity bias in this way suggests that large spectroscopic surveys can improve dispersion-based mass-observable scaling relations for cosmology even in the face of velocity biases, by quantifying and ultimately calibrating them out.

Velocity distribution in a turbulent flow near a rough wall

Science.gov (United States)

Korsun, A. S.; Pisarevsky, M. I.; Fedoseev, V. N.; Kreps, M. V.

2017-11-01

Velocity distribution in the zone of developed wall turbulence, regardless of the conditions on the wall, is described by the well-known Prandtl logarithmic profile. In this distribution, the constant, that determines the value of the velocity, is determined by the nature of the interaction of the flow with the wall and depends on the viscosity of the fluid, the dynamic velocity, and the parameters of the wall roughness.In extreme cases depending on the ratio between the thickness of the viscous sublayer and the size of the roughness the constant takes on a value that does not depend on viscosity, or leads to a ratio for a smooth wall.It is essential that this logarithmic profile is the result not only of the Prandtl theory, but can be derived from general considerations of the theory of dimensions, and also follows from the condition of local equilibrium of generation and dissipation of turbulent energy in the wall area. This allows us to consider the profile as a universal law of velocity distribution in the wall area of a turbulent flow.The profile approximation up to the maximum speed line with subsequent integration makes possible to obtain the resistance law for channels of simple shape. For channels of complex shape with rough walls, the universal profile can be used to formulate the boundary condition when applied to the calculation of turbulence models.This paper presents an empirical model for determining the constant of the universal logarithmic profile. The zone of roughness is described by a set of parameters and is considered as a porous structure with variable porosity.

Demonstrating Kinematics and Newton's Laws in a Jump

Science.gov (United States)

Kamela, Martin

2007-01-01

When students begin the study of Newton's laws they are generally comfortable with static equilibrium type problems, but dynamic examples where forces are not constant are more challenging. The class exercise presented here helps students to develop an intuitive grasp of both the position-velocity-acceleration relation and the force-acceleration…

Numerical calculation of velocity distribution near a vertical flat plate immersed in bubble flow

International Nuclear Information System (INIS)

Matsuura, Akihiro; Nakamura, Hajime; Horihata, Hideyuki; Hiraoka, Setsuro; Aragaki, Tsutomu; Yamada, Ikuho; Isoda, Shinji.

1992-01-01

Liquid and gas velocity distributions for bubble flow near a vertical flat plate were calculated numerically by using the SIMPLER method, where the flow was assumed to be laminar, two-dimensional, and at steady state. The two-fluid flow model was used in the numerical analysis. To calculate the drag force on a small bubble, Stokes' law for a rigid sphere is applicable. The dimensionless velocity distributions which were arranged with characteristic boundary layer thickness and maximum liquid velocity were adjusted with a single line and their forms were similar to that for single-phase wall-jet flow. The average wall shear stress derived from the velocity gradient at the plate wall was strongly affected by bubble diameter but not by inlet liquid velocity. The present dimensionless velocity distributions obtained numerically agreed well with previous experimental results, and the proposed numerical algorithm was validated. (author)

A Review of Darcy's Law: Limitations and Alternatives for Predicting Solute Transport

Science.gov (United States)

Steenhuis, Tammo; Kung, K.-J. Sam; Jaynes, Dan; Helling, Charles S.; Gish, Tim; Kladivko, Eileen

2016-04-01

Darcy's Law that was derived originally empirically 160 years ago, has been used successfully in calculating the (Darcy) flux in porous media throughout the world. However, field and laboratory experiments have demonstrated that the Darcy flux employed in the convective disperse equation could only successfully predict solute transport under two conditions: (1) uniformly or densely packed porous media; and (2) field soils under relatively dry condition. Employing the Darcy flux for solute transport in porous media with preferential flow pathways was problematic. In this paper we examine the theoretical background behind these field and laboratory observations and then provide an alternative to predict solute movement. By examining the characteristics of the momentum conservation principles on which Darcy's law is based, we show under what conditions Darcy flux can predict solute transport in porous media of various complexity. We find that, based on several case studies with capillary pores, Darcy's Law inherently merges momentum and in that way erases information on pore-scale velocities. For that reason the Darcy flux cannot predict flow in media with preferential flow conduits where individual pore velocities are essential in predicting the shape of the breakthrough curve and especially "the early arrival" of solutes. To overcome the limitations of the assumption in Darcy's law, we use Jury's conceptualization and employ the measured chemical breakthrough curve as input to characterize the impact of individual preferential flow pathways on chemical transport. Specifically, we discuss how best to take advantage of Jury's conceptualization to extract the pore-scale flow velocity to accurately predict chemical transport through soils with preferential flow pathways.

STARE velocities: 2. Evening westward electron flow

Directory of Open Access Journals (Sweden)

M. Uspensky

2004-04-01

Full Text Available Four evening events and one morning event of joint EISCAT/STARE observations during ~22h are considered and the differences between observed STARE line-of-sight (l-o-s velocities and EISCAT electron drift velocities projected onto the STARE beams are studied. We demonstrate that the double-pulse technique, which is currently in use in the STARE routine data handling, typically underestimates the true phase velocity as inferred from the multi-pulse STARE data. We show that the STARE velocities are persistently smaller (1.5–2 times than the EISCAT velocities, even for the multi-pulse data. The effect seems to be more pronounced in the evening sector when the Finland radar observes at large flow angles. We evaluate the performance of the ion-acoustic approach (IAA, Nielsen and Schlegel, 1985 and the off-orthogonal fluid approach (OOFA, Uspensky et al., 2003 techniques to predict the true electron drift velocity for the base event of 12 February 1999. The IAA technique predicts the convection reasonably well for enhanced flows of >~1000m/s, but not so well for slower ones. By considering the EISCAT N(h profiles, we derive the effective aspect angle and effective altitude of backscatter, and use this information for application of the OOFA technique. We demonstrate that the OOFA predictions for the base event are superior over the IAA predictions and thus, we confirm that OOFA predicts the electron velocities reasonably well in the evening sector, in addition to the morning sector, as concluded by Uspensky et al. (2003. To check how "robust" the OOFA model is and how successful it is for convection estimates without the EISCAT support, we analysed three additional evening events and one additional morning event for which information on N(h profiles was intentionally ignored. By accepting the mean STARE/EISCAT velocity ratio of 0.55 and the mean azimuth rotation of 9° (derived for the basic event, we show that the OOFA performs

Numerical simulation of heat transfer in power law fluid flow through a stenosed artery

Science.gov (United States)

Talib, Amira Husni; Abdullah, Ilyani

2017-11-01

A numerical study of heat transfer in a power law fluid is investigated in this paper. The blood flow is treated as power law fluid with a presence of cosine shaped stenosis. This study reveals the effect of stenosis on the heat transfer and velocity of blood flowing in the constricted artery. The governing and energy equations are formulated in a cylindrical coordinate system. Hence, the set of equations and boundary conditions are solved numerically by Marker and Cell (MAC) method. The graphical result shows the profile of blood temperature is increased while the blood velocity is decreased at the critical height of stenosis.

Electrohydrodynamic stability of two stratified power law liquid in couette flow

International Nuclear Information System (INIS)

Eldabe, N.T.

1988-01-01

Consideration is given to the stability of the flow of two power law liquids under the influence of normal electric field between two infinite parallel planes when one of the planes moves with constant velocity in its own plane. It is found that the electric fields have a dramatic effect and can be chosen to stabilize or destabilize the flow. The effects of the power law parameters on the problem are examinated

Hubble, Hubble's Law and the Expanding Universe

Indian Academy of Sciences (India)

Srimath

H ubble's nam e is associated closely w ith the idea of an expanding universe as he discovered the relation between the recession velocity and the distances of galaxies. H ubble also did a lot of pioneering w ork on the distribution of galaxies in the universe. In this article we take a look at H ubble's law and discuss how it ...

Diurnal Dynamics of Standard Deviations of Three Wind Velocity Components in the Atmospheric Boundary Layer

Science.gov (United States)

Shamanaeva, L. G.; Krasnenko, N. P.; Kapegesheva, O. F.

2018-04-01

Diurnal dynamics of the standard deviation (SD) of three wind velocity components measured with a minisodar in the atmospheric boundary layer is analyzed. Statistical analysis of measurement data demonstrates that the SDs for x- and y-components σx and σy lie in the range from 0.2 to 4 m/s, and σz = 0.1-1.2 m/s. The increase of σx and σy with the altitude is described sufficiently well by a power law with exponent changing from 0.22 to 1.3 depending on time of day, and σz increases by a linear law. Approximation constants are determined and errors of their application are estimated. It is found that the maximal diurnal spread of SD values is 56% for σx and σy and 94% for σz. The established physical laws and the obtained approximation constants allow the diurnal dynamics of the SDs for three wind velocity components in the atmospheric boundary layer to be determined and can be recommended for application in models of the atmospheric boundary layer.

Sound Velocity in Soap Foams

International Nuclear Information System (INIS)

Wu Gong-Tao; Lü Yong-Jun; Liu Peng-Fei; Li Yi-Ning; Shi Qing-Fan

2012-01-01

The velocity of sound in soap foams at high gas volume fractions is experimentally studied by using the time difference method. It is found that the sound velocities increase with increasing bubble diameter, and asymptotically approach to the value in air when the diameter is larger than 12.5 mm. We propose a simple theoretical model for the sound propagation in a disordered foam. In this model, the attenuation of a sound wave due to the scattering of the bubble wall is equivalently described as the effect of an additional length. This simplicity reasonably reproduces the sound velocity in foams and the predicted results are in good agreement with the experiments. Further measurements indicate that the increase of frequency markedly slows down the sound velocity, whereas the latter does not display a strong dependence on the solution concentration

Optimal velocity in the race over variable slope trace.

Science.gov (United States)

Maroński, Ryszard; Samoraj, Piotr

2015-01-01

The minimum-time running problem is reconsidered. The time of covering a given distance is minimized. The function that should be found is the runner's velocity that varies with the distance. The Hill-Keller model of motion is employed. It is based on the Newton second law and an equation of power balance. The new element of the current approach is that the trace slope angle varies with the distance. The problem is formulated and solved in optimal control applying the Chebyshev direct pseudospectral method. The essential finding is that the optimal velocity during the cruise is constant regardless of the local slope of the terrain. Such result is valid if the inequality constraints imposed on the propulsive force or the energy are not active.

Certain laws governing the influence of high molecular polymer additives on specific electrical conductivity and viscosity of zincate alkaline solution

Energy Technology Data Exchange (ETDEWEB)

Dmitrenko, V.Ye.; Toropetsera, T.N.; Zubov, M.S.

1983-01-01

A study was made of the influence of polymer additives of different nature: polyelectrolyte, copolymer of ethylene with maleic anhydride, polymethacrylic acid and nonpolyectrolyte copolymer of vinyl alcohol with vinyleneglycol and polyvinyleneglycol on specific electrical conductance and viscosity of the zincate alkaline solution. It is indicated that with an increase in the content of additives, the specific conductance of the solution diminishes according to a linear law, while the viscosity rises. The additives of polyelectrolyte nature reduce more strongly the specific conductance and increase the viscosity than the nonpolyelectrolyte additives. From a comparison of the data on specific conductance and viscosity the following conclusion is drawn: the more the polymer ''structures'' the zincate alkaline solution, the more strongly it reduces its specific electrical conductance.

Rotating Hele-Shaw cell with a time-dependent angular velocity

Science.gov (United States)

Anjos, Pedro H. A.; Alvarez, Victor M. M.; Dias, Eduardo O.; Miranda, José A.

2017-12-01

Despite the large number of existing studies of viscous flows in rotating Hele-Shaw cells, most investigations analyze rotational motion with a constant angular velocity, under vanishing Reynolds number conditions in which inertial effects can be neglected. In this work, we examine the linear and weakly nonlinear dynamics of the interface between two immiscible fluids in a rotating Hele-Shaw cell, considering the action of a time-dependent angular velocity, and taking into account the contribution of inertia. By using a generalized Darcy's law, we derive a second-order mode-coupling equation which describes the time evolution of the interfacial perturbation amplitudes. For arbitrary values of viscosity and density ratios, and for a range of values of a rotational Reynolds number, we investigate how the time-dependent angular velocity and inertia affect the important finger competition events that traditionally arise in rotating Hele-Shaw flows.

Measuring average angular velocity with a smartphone magnetic field sensor

Science.gov (United States)

Pili, Unofre; Violanda, Renante

2018-02-01

The angular velocity of a spinning object is, by standard, measured using a device called a tachometer. However, by directly using it in a classroom setting, the activity is likely to appear as less instructive and less engaging. Indeed, some alternative classroom-suitable methods for measuring angular velocity have been presented. In this paper, we present a further alternative that is smartphone-based, making use of the real-time magnetic field (simply called B-field in what follows) data gathering capability of the B-field sensor of the smartphone device as the timer for measuring average rotational period and average angular velocity. The in-built B-field sensor in smartphones has already found a number of uses in undergraduate experimental physics. For instance, in elementary electrodynamics, it has been used to explore the well-known Bio-Savart law and in a measurement of the permeability of air.

Scaling laws for a compliant biomimetic swimmer

Science.gov (United States)

Gibouin, Florence; Raufaste, Christophe; Bouret, Yann; Argentina, Mederic

2017-11-01

Motivated by the seminal work of Lord Lighthill in the sixties, we study the motion of inertial aquatic swimmers that propels with undulatory gaits. In 2014, Gazzola et al. have uncovered the law linking the swimming velocity to the kinematics of the swimmer and the fluid properties. At high Reynolds numbers, the velocity appears to be equal to 0.4 Af /(2 π) , where A and f are respectively the amplitude and the frequency of the oscillating fin. We have constructed a compliant biomimetic swimmer, whose muscles have been modeled through a torque distribution thanks to a servomotor. A soft polymeric material mimics the flesh and provides the flexibility. By immersing our robot into a water tunnel, we find and characterize the operating point for which the propulsive force balances the drag. We bring the first experimental proof of the former law and probe large amplitude undulations which exhibits nonlinear effects. All data collapse perfectly onto a single master curve. We investigate the role of the fin flexibility by varying its length and its thickness and we figured out the existence of an efficient swimming regime. We thank the support of CNRS and Université Côte d'Azur.

Revision of Paschen's Law Relating to the ESD of Aerospace Vehicle Surfaces

Science.gov (United States)

Hogue, Michael D.; Cox, Rachel E.; Mulligan, Jaysen; Kapat, Jayanta; Ahmed, Kareem; Wilson, Jennifer G.; Calle, Luz M.

2017-01-01

The purpose of this work is to develop a version of Paschen's law that takes into account the flow of ambient gas past electrode surfaces. Paschen's law does not consider the flow of gas past an aerospace vehicle whose surfaces may be triboelectrically charged by dust or ice crystal impingement while traversing the atmosphere. The basic hypothesis of this work is that the number of electron-ion pairs created per unit distance between electrode surfaces is mitigated by the electron-ion pairs removed per unit distance by the flow of gas. The revised theoretical model must be a function of the mean velocity vxm of the ambient gas and reduce to Paschen's law when the mean velocity is zero. A new theoretical formulation of Paschen's law, taking into account the Mach number and compressible dynamic pressure, derived by the authors, will be discussed. This equation has been evaluated by wind tunnel experimentation. Initial data of the baseline wind tunnel experiments show results consistent with the hypothesis. This work may enhance the safety of aerospace vehicles through a redefinition of electrostatic launch commit criteria. It is also possible for new products, such as antistatic coatings, to be formulated based on this data.

Toward a physics-based rate and state friction law for earthquake nucleation processes in fault zones with granular gouge

Science.gov (United States)

Ferdowsi, B.; Rubin, A. M.

2017-12-01

Numerical simulations of earthquake nucleation rely on constitutive rate and state evolution laws to model earthquake initiation and propagation processes. The response of different state evolution laws to large velocity increases is an important feature of these constitutive relations that can significantly change the style of earthquake nucleation in numerical models. However, currently there is not a rigorous understanding of the physical origins of the response of bare rock or gouge-filled fault zones to large velocity increases. This in turn hinders our ability to design physics-based friction laws that can appropriately describe those responses. We here argue that most fault zones form a granular gouge after an initial shearing phase and that it is the behavior of the gouge layer that controls the fault friction. We perform numerical experiments of a confined sheared granular gouge under a range of confining stresses and driving velocities relevant to fault zones and apply 1-3 order of magnitude velocity steps to explore dynamical behavior of the system from grain- to macro-scales. We compare our numerical observations with experimental data from biaxial double-direct-shear fault gouge experiments under equivalent loading and driving conditions. Our intention is to first investigate the degree to which these numerical experiments, with Hertzian normal and Coulomb friction laws at the grain-grain contact scale and without any time-dependent plasticity, can reproduce experimental fault gouge behavior. We next compare the behavior observed in numerical experiments with predictions of the Dieterich (Aging) and Ruina (Slip) friction laws. Finally, the numerical observations at the grain and meso-scales will be used for designing a rate and state evolution law that takes into account recent advances in rheology of granular systems, including local and non-local effects, for a wide range of shear rates and slow and fast deformation regimes of the fault gouge.

Laws on Sex Discrimination in Employment. Federal Civil Rights Act, Title VII State Fair Employment Practices Laws, Executive Orders.

Science.gov (United States)

Women's Bureau (DOL), Washington, DC.

This report describes the applicable laws regarding sex discrimination in employment. In addition to Federal law and two relevant Executive Orders, the report includes 21 state laws and the District of Columbia's law prohibiting discrimination based on sex. This document is a revision of ED 014 611. (BH)

Dual plane problems for creeping flow of power-law incompressible medium

Directory of Open Access Journals (Sweden)

Dmitriy S. Petukhov

2016-09-01

Full Text Available In this paper, we consider the class of solutions for a creeping plane flow of incompressible medium with power-law rheology, which are written in the form of the product of arbitrary power of the radial coordinate by arbitrary function of the angular coordinate of the polar coordinate system covering the plane. This class of solutions represents the asymptotics of fields in the vicinity of singular points in the domain occupied by the examined medium. We have ascertained the duality of two problems for a plane with wedge-shaped notch, at which boundaries in one of the problems the vector components of the surface force vanish, while in the other—the vanishing components are the vector components of velocity, We have investigated the asymptotics and eigensolutions of the dual nonlinear eigenvalue problems in relation to the rheological exponent and opening angle of the notch for the branch associated with the eigenvalue of the Hutchinson–Rice–Rosengren problem learned from the problem of stress distribution over a notched plane for a power law medium. In the context of the dual problem we have determined the velocity distribution in the flow of power-law medium at the vertex of a rigid wedge, We have also found another two eigenvalues, one of which was determined by V. V. Sokolovsky for the problem of power-law fluid flow in a convergent channel.

Identifying Coronary Artery Disease in Asymptomatic Middle-Aged Sportsmen: The Additional Value of Pulse Wave Velocity.

Directory of Open Access Journals (Sweden)

Thijs L Braber

Full Text Available Cardiovascular screening may benefit middle-aged sportsmen, as coronary artery disease (CAD is the main cause of exercise-related sudden cardiac death. Arterial stiffness, as measured by pulse wave velocity (PWV, may help identify sportsmen with subclinical CAD. We examined the additional value of PWV measurements to traditional CAD risk factors for identifying CAD.From the Measuring Athlete's Risk of Cardiovascular events (MARC cohort of asymptomatic, middle-aged sportsmen who underwent low-dose Cardiac CT (CCT after routine sports medical examination (SME, 193 consecutive sportsmen (aged 55 ± 6.6 years were included with additional PWV measurements before CCT. Sensitivity, specificity and predictive values of PWV values (>8.3 and >7.5 m/s assessed by Arteriograph were used to identify CAD (coronary artery calcium scoring ≥ 100 Agatston Units or coronary CT angiography luminal stenosis ≥ 50% and to assess the additional diagnostic value of PWV to established cardiovascular risk factors.Forty-seven sportsmen (24% had CAD on CCT. They were older (58.9 vs. 53.8 years, p8.3m/s respectively >7.5 m/s sensitivity to detect CAD on CT was 43% and 74%, specificity 69% and 45%, positive predictive value 31% and 30%, and negative predictive value 79% and 84%. Adding PWV to traditional risk factor models did not change the area under the curve (from 0.78 (95% CI = 0.709-0.848 to AUC 0.78 (95% CI 0.710-0.848, p = 0.99 for prediction of CAD on CCT.Limited additional value was found for PWV on top of established risk factors to identify CAD. PWV might still have a role to identify CAD in middle-aged sportsmen if risk factors such as cholesterol are unknown.

Divorce by consent in Roman law and contemporary law

Directory of Open Access Journals (Sweden)

Ignjatović Marija

2013-01-01

Full Text Available The subject matter of this paper is divorce by mutual consent in Roman law and contemporary law. In the first part of this article, the authors analyzes the key tenets of consensual divorce in Roman law, with specific reference to the impact of Christian religious teaching on the concepts of marriage and divorce as well as on the Roman rulers' constitutions, which marked the beginning of the process of restricting the right to divorce. In the central part of the paper, the authors examines the regulation on the consensual divorce in some contemporary legal systems. In addition, the authors provides a substantial analysis of the normative framework on the termination of marriage in the positive Serbian legislation. In the final part of the paper, the authors provides a comparative analysis and underscores the observed similarities and differenced in the regulation of the institute of consensual divorce in Roman law and in the contemporary legislation.

The Velocity Distribution of Isolated Radio Pulsars

Science.gov (United States)

Arzoumanian, Z.; Chernoff, D. F.; Cordes, J. M.; White, Nicholas E. (Technical Monitor)

2002-01-01

We infer the velocity distribution of radio pulsars based on large-scale 0.4 GHz pulsar surveys. We do so by modelling evolution of the locations, velocities, spins, and radio luminosities of pulsars; calculating pulsed flux according to a beaming model and random orientation angles of spin and beam; applying selection effects of pulsar surveys; and comparing model distributions of measurable pulsar properties with survey data using a likelihood function. The surveys analyzed have well-defined characteristics and cover approx. 95% of the sky. We maximize the likelihood in a 6-dimensional space of observables P, dot-P, DM, absolute value of b, mu, F (period, period derivative, dispersion measure, Galactic latitude, proper motion, and flux density). The models we test are described by 12 parameters that characterize a population's birth rate, luminosity, shutoff of radio emission, birth locations, and birth velocities. We infer that the radio beam luminosity (i) is comparable to the energy flux of relativistic particles in models for spin-driven magnetospheres, signifying that radio emission losses reach nearly 100% for the oldest pulsars; and (ii) scales approximately as E(exp 1/2) which, in magnetosphere models, is proportional to the voltage drop available for acceleration of particles. We find that a two-component velocity distribution with characteristic velocities of 90 km/ s and 500 km/ s is greatly preferred to any one-component distribution; this preference is largely immune to variations in other population parameters, such as the luminosity or distance scale, or the assumed spin-down law. We explore some consequences of the preferred birth velocity distribution: (1) roughly 50% of pulsars in the solar neighborhood will escape the Galaxy, while approx. 15% have velocities greater than 1000 km/ s (2) observational bias against high velocity pulsars is relatively unimportant for surveys that reach high Galactic absolute value of z distances, but is severe for

Velocity Profiles of Slow Blood Flow in a Narrow Tube

Science.gov (United States)

Chen, Jinyu; Huang, Zuqia; Zhuang, Fengyuan; Zhang, Hui

1998-04-01

A fractal model is introduced into the slow blood motion. When blood flows slowly in a narrow tube, red cell aggregation results in the formation of an approximately cylindrical core of red cells. By introducing the fractal model and using the power law relation between area fraction φ and distance from tube axis ρ, rigorous velocity profiles of the fluid in and outside the aggregated core and of the core itself are obtained analytically for different fractal dimensions. It shows a blunted velocity distribution for a relatively large fractal dimension (D ˜ 2), which can be observed in normal blood; a pathological velocity profile for moderate dimension (D = 1), which is similar to the Segre-Silberberg effect; and a parabolic profile for negligible red cell concentration (D = 0), which likes in the Poiseuille flow. The project supported by the National Basic Research Project "Nonlinear Science", National Natural Science Foundation of China and the State Education Commission through the Foundation of Doctoral Training

Numerical model for verification of constitutive laws of blood vessel wall

Czech Academy of Sciences Publication Activity Database

Macková, H.; Chlup, Hynek; Žitný, R.

-, 2/1 (2007), s. 66-66 ISSN 1880-9863 Institutional research plan: CEZ:AV0Z20760514 Keywords : constitutive law * numerical model * pulse wave velocity Subject RIV: BK - Fluid Dynamics http://www.jstage.jst.go.jp/browse/jbse/2/Suppl.1/_contents

Continuous measurements of in-bore projectile velocity

International Nuclear Information System (INIS)

Asay, J.R.; Konrad, C.H.; Hall, C.A.; Shahinpoor, M.

1989-01-01

The application of velocity interferometry to the continuous measurement of in-bore projectile velocity in a small-bore three-stage railgun is described. These measurements are useful for determining projectile acceleration and for evaluating gun performance. The launcher employed in these studies consists of a two-stage light gas gun used to inject projectiles into a railgun for additional acceleration. Results obtained for projectile velocities to 7.4 km/s with the two-stage injector are reported and potential improvements for railgun applications are discussed

Constraining the optical depth of galaxies and velocity bias with cross-correlation between the kinetic Sunyaev-Zeldovich effect and the peculiar velocity field

Science.gov (United States)

Ma, Yin-Zhe; Gong, Guo-Dong; Sui, Ning; He, Ping

2018-03-01

We calculate the cross-correlation function between the kinetic Sunyaev-Zeldovich (kSZ) effect and the reconstructed peculiar velocity field using linear perturbation theory, with the aim of constraining the optical depth τ and peculiar velocity bias of central galaxies with Planck data. We vary the optical depth τ and the velocity bias function bv(k) = 1 + b(k/k0)n, and fit the model to the data, with and without varying the calibration parameter y0 that controls the vertical shift of the correlation function. By constructing a likelihood function and constraining the τ, b and n parameters, we find that the quadratic power-law model of velocity bias, bv(k) = 1 + b(k/k0)2, provides the best fit to the data. The best-fit values are τ = (1.18 ± 0.24) × 10-4, b=-0.84^{+0.16}_{-0.20} and y0=(12.39^{+3.65}_{-3.66})× 10^{-9} (68 per cent confidence level). The probability of b > 0 is only 3.12 × 10-8 for the parameter b, which clearly suggests a detection of scale-dependent velocity bias. The fitting results indicate that the large-scale (k ≤ 0.1 h Mpc-1) velocity bias is unity, while on small scales the bias tends to become negative. The value of τ is consistent with the stellar mass-halo mass and optical depth relationship proposed in the literature, and the negative velocity bias on small scales is consistent with the peak background split theory. Our method provides a direct tool for studying the gaseous and kinematic properties of galaxies.

Velocity distribution in snow avalanches

Science.gov (United States)

Nishimura, K.; Ito, Y.

1997-12-01

In order to investigate the detailed structure of snow avalanches, we have made snow flow experiments at the Miyanomori ski jump in Sapporo and systematic observations in the Shiai-dani, Kurobe Canyon. In the winter of 1995-1996, a new device to measure static pressures was used to estimate velocities in the snow cloud that develops above the flowing layer of avalanches. Measurements during a large avalanche in the Shiai-dani which damaged and destroyed some instruments indicate velocities increased rapidly to more than 50 m/s soon after the front. Velocities decreased gradually in the following 10 s. Velocities of the lower flowing layer were also calculated by differencing measurement of impact pressure. Both recordings in the snow cloud and in the flowing layer changed with a similar trend and suggest a close interaction between the two layers. In addition, the velocity showed a periodic change. Power spectrum analysis of the impact pressure and the static pressure depression showed a strong peak at a frequency between 4 and 6 Hz, which might imply the existence of either ordered structure or a series of surges in the flow.

Development of a digital automatic control law for steep glideslope capture and flare

Science.gov (United States)

Halyo, N.

1977-01-01

A longitudinal digital guidance and control law for steep glideslopes using MLS (Microwave Landing System) data is developed for CTOL aircraft using modern estimation and control techniques. The control law covers the final approach phases of glideslope capture, glideslope tracking, and flare to touchdown for automatic landings under adverse weather conditions. The control law uses a constant gain Kalman filter to process MLS and body-mounted accelerometer data to form estimates of flight path errors and wind velocities including wind shear. The flight path error estimates and wind estimates are used for feedback in generating control surface commands. Results of a digital simulation of the aircraft dynamics and the guidance and control law are presented for various wind conditions.

Study on Droplet Size and Velocity Distributions of a Pressure Swirl Atomizer Based on the Maximum Entropy Formalism

Directory of Open Access Journals (Sweden)

Kai Yan

2015-01-01

Full Text Available A predictive model for droplet size and velocity distributions of a pressure swirl atomizer has been proposed based on the maximum entropy formalism (MEF. The constraint conditions of the MEF model include the conservation laws of mass, momentum, and energy. The effects of liquid swirling strength, Weber number, gas-to-liquid axial velocity ratio and gas-to-liquid density ratio on the droplet size and velocity distributions of a pressure swirl atomizer are investigated. Results show that model based on maximum entropy formalism works well to predict droplet size and velocity distributions under different spray conditions. Liquid swirling strength, Weber number, gas-to-liquid axial velocity ratio and gas-to-liquid density ratio have different effects on droplet size and velocity distributions of a pressure swirl atomizer.

Origin of the inertial deviation from Darcy's law: An investigation from a microscopic flow analysis on two-dimensional model structures

Science.gov (United States)

Agnaou, Mehrez; Lasseux, Didier; Ahmadi, Azita

2017-10-01

identification of a correlation between the flow structure and the different inertial regimes. These components correspond to the curvature of the flow streamlines weighted by the local fluid kinetic energy on the one hand and the distribution of the kinetic energy along these lines on the other hand. In addition, the role of the recirculation zones in the occurrence and in the form of the deviation from Darcy's law was thoroughly analyzed. For the porous structures under consideration, it is shown that (1) the kinetic energy lost in the vortices is insignificant even at high filtration velocities and (2) the shape of the flow streamlines induced by the recirculation zones plays an important role in the variation of the flow structure, which is correlated itself to the different flow regimes.

ROTATIONAL VELOCITIES FOR M DWARFS

International Nuclear Information System (INIS)

Jenkins, J. S.; Ramsey, L. W.; Jones, H. R. A.; Pavlenko, Y.; Barnes, J. R.; Pinfield, D. J.; Gallardo, J.

2009-01-01

We present spectroscopic rotation velocities (v sin i) for 56 M dwarf stars using high-resolution Hobby-Eberly Telescope High Resolution Spectrograph red spectroscopy. In addition, we have also determined photometric effective temperatures, masses, and metallicities ([Fe/H]) for some stars observed here and in the literature where we could acquire accurate parallax measurements and relevant photometry. We have increased the number of known v sin i values for mid M stars by around 80% and can confirm a weakly increasing rotation velocity with decreasing effective temperature. Our sample of v sin is peak at low velocities (∼3 km s -1 ). We find a change in the rotational velocity distribution between early M and late M stars, which is likely due to the changing field topology between partially and fully convective stars. There is also a possible further change in the rotational distribution toward the late M dwarfs where dust begins to play a role in the stellar atmospheres. We also link v sin i to age and show how it can be used to provide mid-M star age limits. When all literature velocities for M dwarfs are added to our sample, there are 198 with v sin i ≤ 10 km s -1 and 124 in the mid-to-late M star regime (M3.0-M9.5) where measuring precision optical radial velocities is difficult. In addition, we also search the spectra for any significant Hα emission or absorption. Forty three percent were found to exhibit such emission and could represent young, active objects with high levels of radial-velocity noise. We acquired two epochs of spectra for the star GJ1253 spread by almost one month and the Hα profile changed from showing no clear signs of emission, to exhibiting a clear emission peak. Four stars in our sample appear to be low-mass binaries (GJ1080, GJ3129, Gl802, and LHS3080), with both GJ3129 and Gl802 exhibiting double Hα emission features. The tables presented here will aid any future M star planet search target selection to extract stars with low v

A numerical scheme to calculate temperature and salinity dependent air-water transfer velocities for any gas

Science.gov (United States)

Johnson, M. T.

2010-02-01

The transfer velocity determines the rate of exchange of a gas across the air-water interface for a given deviation from Henry's law equilibrium between the two phases. In the thin film model of gas exchange, which is commonly used for calculating gas exchange rates from measured concentrations of trace gases in the atmosphere and ocean/freshwaters, the overall transfer is controlled by diffusion-mediated films on either side of the air-water interface. Calculating the total transfer velocity (i.e. including the influence from both molecular layers) requires the Henry's law constant and the Schmidt number of the gas in question, the latter being the ratio of the viscosity of the medium and the molecular diffusivity of the gas in the medium. All of these properties are both temperature and (on the water side) salinity dependent and extensive calculation is required to estimate these properties where not otherwise available. The aim of this work is to standardize the application of the thin film approach to flux calculation from measured and modelled data, to improve comparability, and to provide a numerical framework into which future parameter improvements can be integrated. A detailed numerical scheme is presented for the calculation of the gas and liquid phase transfer velocities (ka and kw respectively) and the total transfer velocity, K. The scheme requires only basic physical chemistry data for any gas of interest and calculates K over the full range of temperatures, salinities and wind-speeds observed in and over the ocean. Improved relationships for the wind-speed dependence of ka and for the salinity-dependence of the gas solubility (Henry's law) are derived. Comparison with alternative schemes and methods for calculating air-sea flux parameters shows good agreement in general but significant improvements under certain conditions. The scheme is provided as a downloadable program in the supplementary material, along with input files containing molecular

Validation of MCDS by comparison of predicted with experimental velocity distribution functions in rarefied normal shocks

Science.gov (United States)

Pham-Van-diep, Gerald C.; Erwin, Daniel A.

1989-01-01

Velocity distribution functions in normal shock waves in argon and helium are calculated using Monte Carlo direct simulation. These are compared with experimental results for argon at M = 7.18 and for helium at M = 1.59 and 20. For both argon and helium, the variable-hard-sphere (VHS) model is used for the elastic scattering cross section, with the velocity dependence derived from a viscosity-temperature power-law relationship in the way normally used by Bird (1976).

Data derived from constitutive laws for description of shock wave propagation in concrete. Final report

International Nuclear Information System (INIS)

Eibl, J.; Ockert, J.

1994-01-01

Especially the need to design safe reactor containments, but also the necessity to protect facilities and human beings against impacts induced secondarily by explosions and detonations, demand simulations and design calculations of concrete under shock wave loading. The necessary computer codes are available, but the relevant constitutive laws for concrete with volumetric pressures up to more than 10000 MPa are lacking. Therefore shock wave tests have been carried out to develop such constitutive laws by loading concrete slabs with contact explosions. By the use of hot-molded carbon composition resistors shock waves propagating through the slab were measured. Pressures up to 13900 MPa were registered. Additionally shock wave velocities were determined from the different arrival times of the wave at the gages. By these two measured values and the conservation equations of mass and momentum the needed p-V relationship, the so called Hugoniot-Curve, was established up to 13900 MPa. Using the theory of Mie-Grueneisen and the so called P-α model the Hugoniot-Curve was extended to the equation of state for concrete. In a first step the deviatoric part of the constitutive law was attached from own static experiments considering the existing knowledge of strain rate effects since relevant dynamic tests under extreme loads are not available. With this constitutive law the analysis of the experiments then was backward verified in detail. (orig.) [de

A Simple Derivation of Kepler's Laws without Solving Differential Equations

Science.gov (United States)

Provost, J.-P.; Bracco, C.

2009-01-01

Proceeding like Newton with a discrete time approach of motion and a geometrical representation of velocity and acceleration, we obtain Kepler's laws without solving differential equations. The difficult part of Newton's work, when it calls for non-trivial properties of ellipses, is avoided by the introduction of polar coordinates. Then a simple…

14 CFR 302.17 - Administrative law judges.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Administrative law judges. 302.17 Section... Evidentiary Hearing Proceedings § 302.17 Administrative law judges. (a) Powers and delegation of authority. (1) An administrative law judge shall have the following powers, in addition to any others specified in...

Scaling laws of design parameters for plasma wakefield accelerators

International Nuclear Information System (INIS)

Uhm, Han S.; Nam, In H.; Suk, Hyyong

2012-01-01

Simple scaling laws for the design parameters of plasma wakefield accelerators were obtained using a theoretical model, which were confirmed via particle simulation studies. It was found that the acceleration length was given by Δx=0.804λ p /(1−β g ), where λ p is the plasma wavelength and β g c the propagation velocity of the ion cavity. The acceleration energy can also be given by ΔE=(γ m −1)mc 2 =2.645mc 2 /(1−β g ), where m is the electron rest mass. As expected, the acceleration length and energy increase drastically as β g approached unity. These simple scaling laws can be very instrumental in the design of better-performing plasma wakefield accelerators. -- Highlights: ► Simple scaling laws for the design parameters of laser wakefield accelerators were obtained using a theoretical model. ► The scaling laws for acceleration length and acceleration energy were compared with particle-in-cell simulation results. ► The acceleration length and the energy increase drastically as β g approaches unity. ► These simple scaling laws can be very instrumental in the design of laser wakefield accelerators.

MHD axisymmetric flow of power-law fluid over an unsteady stretching sheet with convective boundary conditions

Directory of Open Access Journals (Sweden)

Jawad Ahmed

Full Text Available This paper examines the boundary layer flow and heat transfer characteristic in power law fluid model over unsteady radially stretching sheet under the influence of convective boundary conditions. A uniform magnetic field is applied transversely to the direction of the flow. The governing time dependent nonlinear boundary layer equations are reduced into nonlinear ordinary differential equations with the help of similarity transformations. The transformed coupled ordinary differential equations are then solved analytically by homotopy analysis method (HAM and numerically by shooting procedure. Effects of various governing parameters like, power law index n, magnetic parameter M, unsteadiness A, suction/injection S, Biot number γ and generalized Prandtl number Pr on velocity, temperature, local skin friction and the local Nusselt number are studied and discussed. It is found from the analysis that the magnetic parameter diminishes the velocity profile and the corresponding thermal boundary layer thickness. Keywords: Axisymmetric flow, Power law fluid, Unsteady stretching, Convective boundary conditions

From Newton's laws to Einstein's theory of relativity

National Research Council Canada - National Science Library

Fang, Li-chih; Chʻu, Yao-chʻüan; Fang, Li Zhi; Fang, L. Z; Li, Zhi Fang; Fang, Lizhi

1987-01-01

...-Morley Experiment Constant New Velocity of Light Speed The of COMPOSITION OF SPEED OF LIGHT The Law of CHAPTER Salviati's Theory of W h o IV TO ship Two Relativity Shot First? CHAPTER V A ROD Space and * T h e Lifetime Moving Lorentz F R O M GALILEO'S PRINCIPLE OF RELATIVITY THE S P E C I A L T H E O R Y OF RELATIVITY principles of th...

Essential physics

CERN Document Server

Matolyak, John

2013-01-01

Systems of Units, Significant Figures, Coordinate Systems, and VectorsSystems of UnitsConversion of UnitsSignificant FiguresScientific NotationTrigonometryCoordinate SystemsVectorsAddition and Subtraction of VectorsGuideline for Determining the Direction of the ResultantMotion in One DimensionDisplacementAverage VelocityAverage SpeedInstantaneous VelocityAccelerationEquations of MotionFree-Falling ObjectTwo-Dimensional Motion and Circular MotionDisplacement, Velocity, and AccelerationEquations of Motion in Two DimensionsProjectile MotionUniform Circular MotionLinear Velocity, Angular Velocity, Period, and FrequencyNonuniform Circular MotionNewton's Laws: Implications and ApplicationsStatement of Newton's LawsDiscussion of Newton's Laws of MotionFree Body DiagramRemarks on the Application of Newton's Second and Third LawsNewton's Gravitational LawMass, Weight, and Newton's Gravitational LawNewton's Third Law and Apparent WeightDynamics of a Uniform Circular MotionNewton's Laws: Friction in Linear and Circular ...

Effects of Velocity Parameters of the Wind on the Line Formation for 32 CYG

Directory of Open Access Journals (Sweden)

Kyung-Mee Kim

1999-12-01

Full Text Available We calculate the theoretical line profiles in order to investigate the influence of various velocity parameters. Line profiles are calculated by using the exponential velocoty law with two acceleration regions for orbital phases 0.70 and 0.06. From this compttation we find that the influence of the wind velocity gradient on a giant star is more important in the region near the star than in the region away from the star. The observed lines show stronger emission than the calculated line profiles and we interpret the difference is caused by the inhomogeniety in the atmosphere of 32 Cyg.

Turbulent conductivity in parallel with iso-velocities in a planar established flow

International Nuclear Information System (INIS)

Jullien, F.

1968-02-01

In this thesis are presented the experimental results obtained during the study of the turbulent diffusion of heat using a wire source in a flat air flow. The Taylor statistical theory laws are well respected in the domain studied. The experiments have made it possible to evaluate the influence of the Reynolds number and of the distance from the wall on the quadratic values of velocity fluctuations and on the Lagrange turbulence scales. In particular, the author has found a correlation between the Lagrange scales and the friction coefficient when the Reynolds number varies. A diffusion law is derived from the Taylor theory; it makes it possible to explain more clearly the idea of turbulent conductivity. (author) [fr

UNIDROITED POSITION AS A SOURCE OF CONTRACT LAW IN THE FUTURE OF INDONESIAN CONTRACT LAW AMANDEMENT

Directory of Open Access Journals (Sweden)

N. Ike Kusmiati

2018-01-01

Full Text Available [Unidroited Position As A Source Of Contract Law In The Future Of Indonesian Contract Law Amandement] Business transaction often faced the issue of ensuring that the rights and obligation are fulfilled as the agreement as agreed, especially when facing the difficulties of the rights and obligation of the parties due to different legal system between countries. Thereore, to answer the problems  the parties will seek legal sources, namely book III of the Civil Code in addition to studying and understanding the principles of internasional commercial contract law, namely UNIDROIT which contains principles that can be adopted as one of the works that seek Standarization of contract law to encourage the harmonization of commercial law international efforts to bring together different business actors between countries, so that the same legal basis is required in the coming renewal of Indonesia contract law. Keyword : Position, UNIDROIT, Law, Contract, Indonesia.

Impacts of variable thermal conductivity on stagnation point boundary layer flow past a Riga plate with variable thickness using generalized Fourier's law

Science.gov (United States)

Shah, S.; Hussain, S.; Sagheer, M.

2018-06-01

This article explores the problem of two-dimensional, laminar, steady and boundary layer stagnation point slip flow over a Riga plate. The incompressible upper-convected Maxwell fluid has been considered as a rheological fluid model. The heat transfer characteristics are investigated with generalized Fourier's law. The fluid thermal conductivity is assumed to be temperature dependent in this study. A system of partial differential equations governing the flow of an upper-convected Maxwell fluid, heat and mass transfer using generalized Fourier's law is developed. The main objective of the article is to inspect the impacts of pertinent physical parameters such as the stretching ratio parameter (0 ⩽ A ⩽ 0.3) , Deborah number (0 ⩽ β ⩽ 0.6) , thermal relaxation parameter (0 ⩽ γ ⩽ 0.5) , wall thickness parameter (0.1 ⩽ α ⩽ 3.5) , slip parameter (0 ⩽ R ⩽ 1.5) , thermal conductivity parameter (0.1 ⩽ δ ⩽ 1.0) and modified Hartmann number (0 ⩽ Q ⩽ 3) on the velocity and temperature profiles. Suitable local similarity transformations have been used to get a system of non-linear ODEs from the governing PDEs. The numerical solutions for the dimensionless velocity and temperature distributions have been achieved by employing an effective numerical method called the shooting method. It is seen that the velocity profile shows the reduction in the velocity for the higher values of viscoelastic parameter and the thermal relaxation parameter. In addition, to enhance the reliability at the maximum level of the obtained numerical results by shooting method, a MATLAB built-in solver bvp4c has also been utilized.

Theoretical skin-friction law in a turbulent boundary layer

International Nuclear Information System (INIS)

Cheskidov, A.

2005-01-01

We study transitional and turbulent boundary layers using a turbulent velocity profile equation recently derived from the Navier-Stokes-alpha and Leray-alpha models. From this equation we obtain a theoretical prediction of the skin-friction coefficient in a wide range of Reynolds numbers based on momentum thickness, and deduce the maximal value of c f max =0.0063 for turbulent velocity profiles. A two-parameter family of solutions to the equation matches experimental data in the transitional boundary layers with different free-stream turbulence intensity, while one-parameter family of solutions, obtained using our skin-friction coefficient law, matches experimental data in the turbulent boundary layer for moderately large Reynolds numbers

A novel nonlinear nano-scale wear law for metallic brake pads.

Science.gov (United States)

Patil, Sandeep P; Chilakamarri, Sri Harsha; Markert, Bernd

2018-05-03

In the present work, molecular dynamics simulations were carried out to investigate the temperature distribution as well as the fundamental friction characteristics such as the coefficient of friction and wear in a disc-pad braking system. A wide range of constant velocity loadings was applied on metallic brake pads made of aluminium, copper and iron with different rotating speeds of a diamond-like carbon brake disc. The average temperature of Newtonian atoms and the coefficient of friction of the brake pad were investigated. The resulting relationship of the average temperature with the speed of the disc as well as the applied loading velocity can be described by power laws. The quantitative description of the volume lost from the brake pads was investigated, and it was found that the volume lost increases linearly with the sliding distance. Our results show that Archard's linear wear law is not applicable to a wide range of normal loads, e.g., in cases of low normal load where the wear rate was increased considerably and in cases of high load where there was a possibility of severe wear. In this work, a new formula for the brake pad wear in a disc brake assembly is proposed, which displays a power law relationship between the lost volume of the metallic brake pads per unit sliding distance and the applied normal load with an exponent of 0.62 ± 0.02. This work provides new insights into the fundamental understanding of the wear mechanism at the nano-scale leading to a new bottom-up wear law for metallic brake pads.

Generalized Faraday law derived from classical forces in a rotating frame

OpenAIRE

Choi, Taeseung

2009-01-01

We show the additional spin dependent classical force due to the rotation of an electron spin's rest frame is essential to derive a spin-Faraday law by using an analogy with the usual Faraday law. The contribution of the additional spin dependent force to the spin-Faraday law is the same as that of the spin geometric phase. With this observations, Faraday law is generalized to include both the usual Faraday and the spin-Faraday laws in a unified manner.

Velocity-space diffusion due to resonant wave-wave scattering of electromagnetic and electrostatic waves in a plasma

International Nuclear Information System (INIS)

Sugaya, Reija

1991-01-01

The velocity-space diffusion equation describing distortion of the velocity distribution function due to resonant wave-wave scattering of electromagnetic and electrostatic waves in an unmagnetized plasma is derived from the Vlasov-Maxwell equations by perturbation theory. The conservation laws for total energy and momentum densities of waves and particles are verified, and the time evolutions of the energy and momentum densities of particles are given in terms of the nonlinear wave-wave coupling coefficient in the kinetic wave equation. (author)

ANALYSIS OF MARANGONI CONVECTION OF NON-NEWTONIAN POWER LAW FLUIDS WITH LINEAR TEMPERATURE DISTRIBUTION

Directory of Open Access Journals (Sweden)

Yan Zhang

2011-01-01

Full Text Available The problem of steady, laminar, thermal Marangoni convection flow of non-Newtonian power law fluid along a horizontal surface with variable surface temperature is studied. The partial differential equations are transformed into ordinary differential equations by using a suitable similarity transformation and analytical approximate solutions are obtained by an efficient transformation, asymptotic expansion and Padé approximants technique. The effects of power law index and Marangoni number on velocity and temperature profiles are examined and discussed.

Frictional velocity-weakening in landslides on Earth and on other planetary bodies.

Science.gov (United States)

Lucas, Antoine; Mangeney, Anne; Ampuero, Jean Paul

2014-03-04

One of the ultimate goals in landslide hazard assessment is to predict maximum landslide extension and velocity. Despite much work, the physical processes governing energy dissipation during these natural granular flows remain uncertain. Field observations show that large landslides travel over unexpectedly long distances, suggesting low dissipation. Numerical simulations of landslides require a small friction coefficient to reproduce the extension of their deposits. Here, based on analytical and numerical solutions for granular flows constrained by remote-sensing observations, we develop a consistent method to estimate the effective friction coefficient of landslides. This method uses a constant basal friction coefficient that reproduces the first-order landslide properties. We show that friction decreases with increasing volume or, more fundamentally, with increasing sliding velocity. Inspired by frictional weakening mechanisms thought to operate during earthquakes, we propose an empirical velocity-weakening friction law under a unifying phenomenological framework applicable to small and large landslides observed on Earth and beyond.

Modular rate laws for enzymatic reactions: thermodynamics, elasticities and implementation.

Science.gov (United States)

Liebermeister, Wolfram; Uhlendorf, Jannis; Klipp, Edda

2010-06-15

Standard rate laws are a key requisite for systematically turning metabolic networks into kinetic models. They should provide simple, general and biochemically plausible formulae for reaction velocities and reaction elasticities. At the same time, they need to respect thermodynamic relations between the kinetic constants and the metabolic fluxes and concentrations. We present a family of reversible rate laws for reactions with arbitrary stoichiometries and various types of regulation, including mass-action, Michaelis-Menten and uni-uni reversible Hill kinetics as special cases. With a thermodynamically safe parameterization of these rate laws, parameter sets obtained by model fitting, sampling or optimization are guaranteed to lead to consistent chemical equilibrium states. A reformulation using saturation values yields simple formulae for rates and elasticities, which can be easily adjusted to the given stationary flux distributions. Furthermore, this formulation highlights the role of chemical potential differences as thermodynamic driving forces. We compare the modular rate laws to the thermodynamic-kinetic modelling formalism and discuss a simplified rate law in which the reaction rate directly depends on the reaction affinity. For automatic handling of modular rate laws, we propose a standard syntax and semantic annotations for the Systems Biology Markup Language. An online tool for inserting the rate laws into SBML models is freely available at www.semanticsbml.org. Supplementary data are available at Bioinformatics online.

Analyzing angular distributions for two-step dissociation mechanisms in velocity map imaging.

Science.gov (United States)

Straus, Daniel B; Butler, Lynne M; Alligood, Bridget W; Butler, Laurie J

2013-08-15

Increasingly, velocity map imaging is becoming the method of choice to study photoinduced molecular dissociation processes. This paper introduces an algorithm to analyze the measured net speed, P(vnet), and angular, β(vnet), distributions of the products from a two-step dissociation mechanism, where the first step but not the second is induced by absorption of linearly polarized laser light. Typically, this might be the photodissociation of a C-X bond (X = halogen or other atom) to produce an atom and a momentum-matched radical that has enough internal energy to subsequently dissociate (without the absorption of an additional photon). It is this second step, the dissociation of the unstable radicals, that one wishes to study, but the measured net velocity of the final products is the vector sum of the velocity imparted to the radical in the primary photodissociation (which is determined by taking data on the momentum-matched atomic cophotofragment) and the additional velocity vector imparted in the subsequent dissociation of the unstable radical. The algorithm allows one to determine, from the forward-convolution fitting of the net velocity distribution, the distribution of velocity vectors imparted in the second step of the mechanism. One can thus deduce the secondary velocity distribution, characterized by a speed distribution P(v1,2°) and an angular distribution I(θ2°), where θ2° is the angle between the dissociating radical's velocity vector and the additional velocity vector imparted to the product detected from the subsequent dissociation of the radical.

Jerky-type phenomena at nanocomposite surfaces : The breakdown of the coulomb friction law

NARCIS (Netherlands)

Hosson, Jeff T.M. De; Pei, Yutao; Chen, Changqiang

This article concentrates on the jerky-type phenomenon of surfaces in relative motion (i.e., a breakdown of the Coulomb friction law) in nanocomposite materials. Physical arguments are provided to understand the dependence of friction on sliding velocity in the sense of self-lubrication. Also

Velocity navigator for motion compensated thermometry.

Science.gov (United States)

Maier, Florian; Krafft, Axel J; Yung, Joshua P; Stafford, R Jason; Elliott, Andrew; Dillmann, Rüdiger; Semmler, Wolfhard; Bock, Michael

2012-02-01

Proton resonance frequency shift thermometry is sensitive to breathing motion that leads to incorrect phase differences. In this work, a novel velocity-sensitive navigator technique for triggering MR thermometry image acquisition is presented. A segmented echo planar imaging pulse sequence was modified for velocity-triggered temperature mapping. Trigger events were generated when the estimated velocity value was less than 0.2 cm/s during the slowdown phase in parallel to the velocity-encoding direction. To remove remaining high-frequency spikes from pulsation in real time, a Kalman filter was applied to the velocity navigator data. A phantom experiment with heating and an initial volunteer experiment without heating were performed to show the applicability of this technique. Additionally, a breath-hold experiment was conducted for comparison. A temperature rise of ΔT = +37.3°C was seen in the phantom experiment, and a root mean square error (RMSE) outside the heated region of 2.3°C could be obtained for periodic motion. In the volunteer experiment, a RMSE of 2.7°C/2.9°C (triggered vs. breath hold) was measured. A novel velocity navigator with Kalman filter postprocessing in real time significantly improves the temperature accuracy over non-triggered acquisitions and suggests being comparable to a breath-held acquisition. The proposed technique might be clinically applied for monitoring of thermal ablations in abdominal organs.

Accelerated radial Fourier-velocity encoding using compressed sensing

Energy Technology Data Exchange (ETDEWEB)

Hilbert, Fabian; Han, Dietbert [Wuerzburg Univ. (Germany). Inst. of Radiology; Wech, Tobias; Koestler, Herbert [Wuerzburg Univ. (Germany). Inst. of Radiology; Wuerzburg Univ. (Germany). Comprehensive Heart Failure Center (CHFC)

2014-10-01

distribution in vessels in the order of the voxel size. Thus, compared to normal Phase Contrast measurements delivering only mean velocities, no additional scan time is necessary to retrieve meaningful velocity spectra in small vessels. (orig.)

Accelerated radial Fourier-velocity encoding using compressed sensing

International Nuclear Information System (INIS)

Hilbert, Fabian; Han, Dietbert

2014-01-01

distribution in vessels in the order of the voxel size. Thus, compared to normal Phase Contrast measurements delivering only mean velocities, no additional scan time is necessary to retrieve meaningful velocity spectra in small vessels. (orig.)

Accelerated radial Fourier-velocity encoding using compressed sensing.

Science.gov (United States)

Hilbert, Fabian; Wech, Tobias; Hahn, Dietbert; Köstler, Herbert

2014-09-01

, compared to normal Phase Contrast measurements delivering only mean velocities, no additional scan time is necessary to retrieve meaningful velocity spectra in small vessels. Copyright © 2013. Published by Elsevier GmbH.

Neural representations of kinematic laws of motion: evidence for action-perception coupling.

Science.gov (United States)

Dayan, Eran; Casile, Antonino; Levit-Binnun, Nava; Giese, Martin A; Hendler, Talma; Flash, Tamar

2007-12-18

Behavioral and modeling studies have established that curved and drawing human hand movements obey the 2/3 power law, which dictates a strong coupling between movement curvature and velocity. Human motion perception seems to reflect this constraint. The functional MRI study reported here demonstrates that the brain's response to this law of motion is much stronger and more widespread than to other types of motion. Compliance with this law is reflected in the activation of a large network of brain areas subserving motor production, visual motion processing, and action observation functions. Hence, these results strongly support the notion of similar neural coding for motion perception and production. These findings suggest that cortical motion representations are optimally tuned to the kinematic and geometrical invariants characterizing biological actions.

Additive versus multiplicative muon conservation

International Nuclear Information System (INIS)

Nemethy, P.

1981-01-01

Experimental elucidation of the question of muon conservation is reviewed. It is shown that neutral-current experiments have not yet yielded information about muonium-antimuonium conversion at the weak-interaction level and that all the charged-current experiments agree that there is no evidence for a multiplicative law. The best limits, from the muon-decay neutrino experiment at LAMPF and from the inverse muon-decay experiment in the CERN neutrino beam, definitely exclude multiplicative law schemes with a branching ratio R approximately 1/2. It is concluded that unless the dynamics conspire to make a multiplicative law with very small R it would appear that muon conservation obeys conserved additive lepton flavor law. (U.K.)

Mimicking the cochlear amplifier in a cantilever beam using nonlinear velocity feedback control

International Nuclear Information System (INIS)

Joyce, Bryan S; Tarazaga, Pablo A

2014-01-01

The mammalian cochlea exhibits a nonlinear amplification which allows mammals to detect a large range of sound pressure levels while maintaining high frequency sensitivity. This work seeks to mimic the cochlea’s nonlinear amplification in a mechanical system. A nonlinear, velocity-based feedback control law is applied to a cantilever beam with piezoelectric actuators. The control law reduces the linear viscous damping of the system while introducing a cubic damping term. The result is a system which is positioned close to a Hopf bifurcation. Modelling and experimental results show that the beam with this control law undergoes a one-third amplitude scaling near the resonance frequency and an amplitude-dependent bandwidth. Both behaviors are characteristic of data obtained from the mammalian cochlea. This work could provide insight on the biological cochlea while producing bio-inspired sensors with a large dynamic range and sharp frequency sensitivity. (papers)

Mimicking the cochlear amplifier in a cantilever beam using nonlinear velocity feedback control

Science.gov (United States)

Joyce, Bryan S.; Tarazaga, Pablo A.

2014-07-01

The mammalian cochlea exhibits a nonlinear amplification which allows mammals to detect a large range of sound pressure levels while maintaining high frequency sensitivity. This work seeks to mimic the cochlea’s nonlinear amplification in a mechanical system. A nonlinear, velocity-based feedback control law is applied to a cantilever beam with piezoelectric actuators. The control law reduces the linear viscous damping of the system while introducing a cubic damping term. The result is a system which is positioned close to a Hopf bifurcation. Modelling and experimental results show that the beam with this control law undergoes a one-third amplitude scaling near the resonance frequency and an amplitude-dependent bandwidth. Both behaviors are characteristic of data obtained from the mammalian cochlea. This work could provide insight on the biological cochlea while producing bio-inspired sensors with a large dynamic range and sharp frequency sensitivity.

A Fourier transform method for Vsin i estimations under nonlinear Limb-Darkening laws

Energy Technology Data Exchange (ETDEWEB)

Levenhagen, R. S., E-mail: ronaldo.levenhagen@gmail.com [Universidade Federal de São Paulo, Depto. Ciências Exatas e da Terra, Rua Prof. Arthur Riedel, 275, Jd. Eldorado, CEP 09972-270 Diadema, SP (Brazil)

2014-12-10

Star rotation offers us a large horizon for the study of many important physical issues pertaining to stellar evolution. Currently, four methods are widely used to infer rotation velocities, namely those related to line width calibrations, on the fitting of synthetic spectra, interferometry, and on Fourier transforms (FTs) of line profiles. Almost all of the estimations of stellar projected rotation velocities using the Fourier method in the literature have been addressed with the use of linear limb-darkening (LD) approximations during the evaluation of rotation profiles and their cosine FTs, which in certain cases, lead to discrepant velocity estimates. In this work, we introduce new mathematical expressions of rotation profiles and their Fourier cosine transforms assuming three nonlinear LD laws—quadratic, square-root, and logarithmic—and study their applications with and without gravity-darkening (GD) and geometrical flattening (GF) effects. Through an analysis of He I models in the visible range accounting for both limb and GD, we find out that, for classical models without rotationally driven effects, all the Vsin i values are too close to each other. On the other hand, taking into account GD and GF, the Vsin i obtained with the linear law result in Vsin i values that are systematically smaller than those obtained with the other laws. As a rule of thumb, we apply these expressions to the FT method to evaluate the projected rotation velocity of the emission B-type star Achernar (α Eri).

The Concept of Law and International Society

DEFF Research Database (Denmark)

Schaumburg-Müller, Sten

Hedley Bull, one of the founders of the School of International Society (English School) relies heavily on H.L.A. Hart in his understanding of law, including international law. The contribution seeks to explore 1) how Bull has creatively made use of Hart's Concept of Law, 2) on which points Hart'......'s theory has short comings, 3) on which additional points Bull's use of the concept of law has short comings, and 4) sketch of ideas how to improve the various short comings.......Hedley Bull, one of the founders of the School of International Society (English School) relies heavily on H.L.A. Hart in his understanding of law, including international law. The contribution seeks to explore 1) how Bull has creatively made use of Hart's Concept of Law, 2) on which points Hart...

Nuclear Energy Law and Arbo Law/Safety Law

International Nuclear Information System (INIS)

Eijnde, J.G. van den

1986-01-01

The legal aspects of radiation protection in the Netherlands are described. Radiation protection is regulated mainly in the Nuclear Energy Law. The Arbo Law also has some sections about radiation protection. The interaction between both laws is discussed. (Auth.)

Fractality and the law of the wall

Science.gov (United States)

Xu, Haosen H. A.; Yang, X. I. A.

2018-05-01

Fluid motions in the inertial range of isotropic turbulence are fractal, with their space-filling capacity slightly below regular three-dimensional objects, which is a consequence of the energy cascade. Besides the energy cascade, the other often encountered cascading process is the momentum cascade in wall-bounded flows. Despite the long-existing analogy between the two processes, many of the thoroughly investigated aspects of the energy cascade have so far received little attention in studies of the momentum counterpart, e.g., the possibility of the momentum-transferring scales in the logarithmic region being fractal has not been considered. In this work, this possibility is pursued, and we discuss one of its implications. Following the same dimensional arguments that lead to the D =2.33 fractal dimension of wrinkled surfaces in isotropic turbulence, we show that the large-scale momentum-carrying eddies may also be fractal and non-space-filling, which then leads to the power-law scaling of the mean velocity profile. The logarithmic law of the wall, on the other hand, corresponds to space-filling eddies, as suggested by Townsend [The Structure of Turbulent Shear Flow (Cambridge University Press, Cambridge, 1980)]. Because the space-filling capacity is an integral geometric quantity, the analysis presented in this work provides us with a low-order quantity, with which, one would be able to distinguish between the logarithmic law and the power law.

The effect of reported high-velocity small raindrops on inferred drop size distributions and derived power laws

Directory of Open Access Journals (Sweden)

H. Leijnse

2010-07-01

Full Text Available It has recently been shown that at high rainfall intensities, small raindrops may fall with much larger velocities than would be expected from their diameters. These were argued to be fragments of recently broken-up larger drops. In this paper we quantify the effect of this phenomenon on raindrop size distribution measurements from a Joss-Waldvogel disdrometer, a 2-D Video Distrometer, and a vertically-pointing Doppler radar. Probability distributions of fall velocities have been parameterized, where the parameters are functions of both rainfall intensity and drop size. These parameterizations have been used to correct Joss-Waldvogel disdrometer measurements for this phenomenon. The effect of these corrections on fitted scaled drop size distributions are apparent but not major. Fitted gamma distributions for three different types of rainfall have been used to simulate drop size measurements. The effect of the high-velocity small drops is shown to be minor. Especially for the purpose of remote sensing of rainfall using radar, microwave links, or optical links, the errors caused by using the slightly different retrieval relations will be masked completely by other error sources.

Development of an optimal automatic control law and filter algorithm for steep glideslope capture and glideslope tracking

Science.gov (United States)

Halyo, N.

1976-01-01

A digital automatic control law to capture a steep glideslope and track the glideslope to a specified altitude is developed for the longitudinal/vertical dynamics of a CTOL aircraft using modern estimation and control techniques. The control law uses a constant gain Kalman filter to process guidance information from the microwave landing system, and acceleration from body mounted accelerometer data. The filter outputs navigation data and wind velocity estimates which are used in controlling the aircraft. Results from a digital simulation of the aircraft dynamics and the control law are presented for various wind conditions.

The gravitational analog of Faraday's induction law

Science.gov (United States)

Zile, Daniel; Overduin, James

2015-04-01

Michael Faraday, the discoverer of electromagnetic induction, was convinced that there must also be a gravitational analog of this law, and he carried out drop-tower experiments in 1849 to look for the electric current induced in a coil by changes in gravitational flux through the coil. This work, now little remembered, was in some ways the first investigation of what we would now call a unified-field theory. We revisit Faraday's experiments in the light of current knowledge and ask what might be learned if they were to be performed today. We then review the gravitational analog for Faraday's law that arises within the vector (or gravito-electromagnetic) approximation to Einstein's theory of general relativity in the weak-field, low-velocity limit. This law relates spinning masses and induced ``mass currents'' rather than spinning charges and electric currents, but is otherwise remarkably similar to its electromagnetic counterpart. The predicted effects are completely unobservable in everyday settings like those envisioned by Faraday, but are thought to be relevant in astrophysical contexts like the accretion disks around collapsed stars, thus bearing out Faraday's remarkable intuition. Undergraduate student.

A simple derivation of Kepler's laws without solving differential equations

International Nuclear Information System (INIS)

Provost, J-P; Bracco, C

2009-01-01

Proceeding like Newton with a discrete time approach of motion and a geometrical representation of velocity and acceleration, we obtain Kepler's laws without solving differential equations. The difficult part of Newton's work, when it calls for non-trivial properties of ellipses, is avoided by the introduction of polar coordinates. Then a simple reconsideration of Newton's figure naturally leads to an explicit expression of the velocity and to the equation of the trajectory. This derivation, which can be fully apprehended by undergraduates or by secondary school teachers (who might use it with their pupils), can be considered as a first application of mechanical concepts to a physical problem of great historical and pedagogical interest

Velocity Memory Effect for polarized gravitational waves

Science.gov (United States)

Zhang, P.-M.; Duval, C.; Gibbons, G. W.; Horvathy, P. A.

2018-05-01

Circularly polarized gravitational sandwich waves exhibit, as do their linearly polarized counterparts, the Velocity Memory Effect: freely falling test particles in the flat after-zone fly apart along straight lines with constant velocity. In the inside zone their trajectories combine oscillatory and rotational motions in a complicated way. For circularly polarized periodic gravitational waves some trajectories remain bounded, while others spiral outward. These waves admit an additional "screw" isometry beyond the usual five. The consequences of this extra symmetry are explored.

Development of an optimal velocity selection method with velocity obstacle

Energy Technology Data Exchange (ETDEWEB)

Kim, Min Geuk; Oh, Jun Ho [KAIST, Daejeon (Korea, Republic of)

2015-08-15

The Velocity obstacle (VO) method is one of the most well-known methods for local path planning, allowing consideration of dynamic obstacles and unexpected obstacles. Typical VO methods separate a velocity map into a collision area and a collision-free area. A robot can avoid collisions by selecting its velocity from within the collision-free area. However, if there are numerous obstacles near a robot, the robot will have very few velocity candidates. In this paper, a method for choosing optimal velocity components using the concept of pass-time and vertical clearance is proposed for the efficient movement of a robot. The pass-time is the time required for a robot to pass by an obstacle. By generating a latticized available velocity map for a robot, each velocity component can be evaluated using a cost function that considers the pass-time and other aspects. From the output of the cost function, even a velocity component that will cause a collision in the future can be chosen as a final velocity if the pass-time is sufficiently long enough.

Three-dimensional time-lapse velocity tomography of an underground longwall panel

Energy Technology Data Exchange (ETDEWEB)

Luxbacher, K.; Westman, E.; Swanson, P.; Karfakis, M. [Virginia Tech., Blacksburg, VA (United States). Dept. of Mining & Minerals Engineering

2008-06-15

Three-dimensional velocity tomograms were generated to image the stress redistribution around an underground coal longwall panel to produce a better understanding of the mechanisms that lead to ground failure, especially rockbursts. Mining-induced microseismic events provided passive sources for the three-dimensional velocity tomography. Surface-mounted geophones monitored microseismic activity for 18 days. Eighteen tomograms were generated and high-velocity regions correlated with high abutment stresses predicted by numerical modeling. Additionally, the high-velocity regions were observed to redistribute as the longwall face retreated, indicating that velocity tomography may be an appropriate technology for monitoring stress redistribution in underground mines.

The inverse square law of gravitation

International Nuclear Information System (INIS)

Cook, A.H.

1987-01-01

The inverse square law of gravitation is very well established over the distances of celestial mechanics, while in electrostatics the law has been shown to be followed to very high precision. However, it is only within the last century that any laboratory experiments have been made to test the inverse square law for gravitation, and all but one has been carried out in the last ten years. At the same time, there has been considerable interest in the possibility of deviations from the inverse square law, either because of a possible bearing on unified theories of forces, including gravitation or, most recently, because of a possible additional fifth force of nature. In this article the various lines of evidence for the inverse square law are summarized, with emphasis upon the recent laboratory experiments. (author)

Further experiments for mean velocity profile of pipe flow at high Reynolds number

Science.gov (United States)

Furuichi, N.; Terao, Y.; Wada, Y.; Tsuji, Y.

2018-05-01

This paper reports further experimental results obtained in high Reynolds number actual flow facility in Japan. The experiments were performed in a pipe flow with water, and the friction Reynolds number was varied up to Reτ = 5.3 × 104. This high Reynolds number was achieved by using water as the working fluid and adopting a large-diameter pipe (387 mm) while controlling the flow rate and temperature with high accuracy and precision. The streamwise velocity was measured by laser Doppler velocimetry close to the wall, and the mean velocity profile, called log-law profile U+ = (1/κ) ln(y+) + B, is especially focused. After careful verification of the mean velocity profiles in terms of the flow rate accuracy and an evaluation of the consistency of the present results with those from previously measurements in a smaller pipe (100 mm), it was found that the value of κ asymptotically approaches a constant value of κ = 0.384.

Evaluation of 'period-generated' control laws for the time-optimal control of reactor power

International Nuclear Information System (INIS)

Bernard, J.A.

1988-01-01

Time-Optimal control of neutronic power has recently been achieved by developing control laws that determine the actuator mechanism velocity necessary to produce a specified reactor period. These laws are designated as the 'MIT-SNL Period-Generated Minimum Time Control Laws'. Relative to time-optimal response, they function by altering the rate of change of reactivity so that the instantaneous period is stepped from infinity to its minimum allowed value, held at that value until the desired power level is attained, and then stepped back to infinity. The results of a systematic evaluation of these laws are presented. The behavior of each term in the control laws is shown and the capability of these laws to control properly the reactor power is demonstrated. Factors affecting the implementation of these laws, such as the prompt neutron lifetime and the differential reactivity worth of the actuators, are discussed. Finally, the results of an experimental study in which these laws were used to adjust the power of the 5 MWt MIT Research Reactor are shown. The information presented should be of interest to those designing high performance control systems for test, spacecraft, or, in certain instances, commercial reactors

On the Velocity of Moving Relativistic Unstable Quantum Systems

Directory of Open Access Journals (Sweden)

K. Urbanowski

2015-01-01

Full Text Available We study properties of moving relativistic quantum unstable systems. We show that in contrast to the properties of classical particles and quantum stable objects the velocity of freely moving relativistic quantum unstable systems cannot be constant in time. We show that this new quantum effect results from the fundamental principles of the quantum theory and physics: it is a consequence of the principle of conservation of energy and of the fact that the mass of the quantum unstable system is not defined. This effect can affect the form of the decay law of moving relativistic quantum unstable systems.

Study on law of negative corona discharge in microparticle-air two-phase flow media

Directory of Open Access Journals (Sweden)

Bo He

2016-03-01

Full Text Available To study the basic law of negative corona discharge in solid particle-air two-phase flow, corona discharge experiments in a needle-plate electrode system at different voltage levels and different wind speed were carried out in the wind tunnel. In this paper, the change law of average current and current waveform were analyzed, and the observed phenomena were systematically explained from the perspectives of airflow, particle charging, and particle motion with the help of PIV (particle image velocity measurements and ultraviolet observations.

Velocity and phase distribution measurements in vertical air-water annular flows

International Nuclear Information System (INIS)

Vassallo, P.

1997-07-01

Annular flow topology for three air-water conditions in a vertical duct is investigated through the use of a traversing double-sensor hot-film anemometry probe and differential pressure measurements. Near wall measurements of mean and fluctuating velocities, as well as local void fraction, are taken in the liquid film, with the highest turbulent fluctuations occurring for the flow condition with the largest pressure drop. A modified law-of-the-wall formulation for wall shear is presented which, using near wall values of mean velocity and kinetic energy, agrees reasonably well with the average stress obtained from direct pressure drop measurements. The linear profile using wall coordinates in the logarithmic layer is preserved in annular flow; however, the slope and intercept of the profile differ from the single-phase values for the annular flow condition which has a thicker, more turbulent, liquid film

Metrical connection in space-time, Newton's and Hubble's laws

International Nuclear Information System (INIS)

Maeder, A.

1978-01-01

The theory of gravitation in general relativity is not scale invariant. Here, we follow Dirac's proposition of a scale invariant theory of gravitation (i.e. a theory in which the equations keep their form when a transformation of scale is made). We examine some concepts of Weyl's geometry, like the metrical connection, the scale transformations and invariance, and we discuss their consequences for the equation of the geodetic motion and for its Newtonian limit. Under general conditions, we show that the only non-vanishing component of the coefficient of metrical connection may be identified with Hubble's constant. In this framework, the equivalent to the Newtonian approximation for the equation of motion contains an additional acceleration term Hdr vector /dt, which produces an expansion of gravitational systems. The velocity of this expansion is shown to increase linearly with the distance between interacting objects. The relative importance of this new expansion term to the Newtonian one varies like (2rhosub(c)/rho)sup(1/2), where rhosub(c) is the critical density of the Einsteinde Sitter model and rho is the mean density of the considered gravitational configuration. Thus, this 'generalized expansion' is important essentially for systems of mean density not too much above the critical density. Finally, our main conclusion is that in the integrable Weyl geometry, Hubble's law - like Newton's law - would appear as an intrinsic property of gravitation, being only the most visible manifestation of a general effect characterizing the gravitational interaction. (orig.) [de

Benford's Law in Astronomy Theodoros Alexopoulos1,∗ & Stefanos ...

Indian Academy of Sciences (India)

2. New numerical sequences and Benford's law. A simple example of Benford's law is performed on numerical sequences. It is already proven that the Fibonacci and Lucas numbers obey the Benford's law. (Wlodarksi 1971). The three additional numerical sequences considered in this paper are: • Jacobsthal numbers (Jn) ...

Cognitive regulation of saccadic velocity by reward prospect.

Science.gov (United States)

Chen, Lewis L; Hung, Leroy Y; Quinet, Julie; Kosek, Kevin

2013-08-01

It is known that expectation of reward speeds up saccades. Past studies have also shown the presence of a saccadic velocity bias in the orbit, resulting from a biomechanical regulation over varying eccentricities. Nevertheless, whether and how reward expectation interacts with the biomechanical regulation of saccadic velocities over varying eccentricities remains unknown. We addressed this question by conducting a visually guided double-step saccade task. The role of reward expectation was tested in monkeys performing two consecutive horizontal saccades, one associated with reward prospect and the other not. To adequately assess saccadic velocity and avoid adaptation, we systematically varied initial eye positions, saccadic directions and amplitudes. Our results confirmed the existence of a velocity bias in the orbit, i.e., saccadic peak velocity decreased linearly as the initial eye position deviated in the direction of the saccade. The slope of this bias increased as saccadic amplitudes increased. Nevertheless, reward prospect facilitated velocity to a greater extent for saccades away from than for saccades toward the orbital centre, rendering an overall reduction in the velocity bias. The rate (slope) and magnitude (intercept) of reward modulation over this velocity bias were linearly correlated with amplitudes, similar to the amplitude-modulated velocity bias without reward prospect, which presumably resulted from a biomechanical regulation. Small-amplitude (≤ 5°) saccades received little modulation. These findings together suggest that reward expectation modulated saccadic velocity not as an additive signal but as a facilitating mechanism that interacted with the biomechanical regulation. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Burning velocity measurements of nitrogen-containing compounds.

Science.gov (United States)

Takizawa, Kenji; Takahashi, Akifumi; Tokuhashi, Kazuaki; Kondo, Shigeo; Sekiya, Akira

2008-06-30

Burning velocity measurements of nitrogen-containing compounds, i.e., ammonia (NH3), methylamine (CH3NH2), ethylamine (C2H5NH2), and propylamine (C3H7NH2), were carried out to assess the flammability of potential natural refrigerants. The spherical-vessel (SV) method was used to measure the burning velocity over a wide range of sample and air concentrations. In addition, flame propagation was directly observed by the schlieren photography method, which showed that the spherical flame model was applicable to flames with a burning velocity higher than approximately 5 cm s(-1). For CH3NH2, the nozzle burner method was also used to confirm the validity of the results obtained by closed vessel methods. We obtained maximum burning velocities (Su0,max) of 7.2, 24.7, 26.9, and 28.3 cm s(-1) for NH3, CH3NH2, C2H5NH2, and C3H7NH2, respectively. It was noted that the burning velocities of NH3 and CH3NH2 were as high as those of the typical hydrofluorocarbon refrigerants difluoromethane (HFC-32, Su0,max=6.7 cm s(-1)) and 1,1-difluoroethane (HFC-152a, Su0,max=23.6 cm s(-1)), respectively. The burning velocities were compared with those of the parent alkanes, and it was found that introducing an NH2 group into hydrocarbon molecules decreases their burning velocity.

Law 6.189 of December 16, 1974

International Nuclear Information System (INIS)

1974-01-01

Modifies Law 4.118 of Aug 27, 1962 and Law 5.740 of Dec 1, 1971, which create respectively, Brazilian Nuclear Energy Commission (CNEN) and Brazilian Company of Nuclear Technology (CBTN), henceforth designated by Empresas Nucleares Brasileiras Sociedade Anonima (NUCLEBRAS) - Brazilian Nuclear Technology Corporation - and makes additional providence

Design definition of the Laser Atmospheric Wind Sounder (LAWS), phase 2. Volume 1: Executive summary

Science.gov (United States)

1992-01-01

The LAWS phase 1 and phase 2 studies have been completed on schedule and have led to significant advances in CO2 laser development. The Phase 2 Design Definition Study has shown that a large scanning mirror/high pulse energy laser LAWS Instrument is feasible and within the existing technology. The capability to monitor wind velocities with backscatter ratios of 10(exp 11) m(exp -1) SR(exp -1) is feasible. The weight budget allocated for the baseline LAWS is adequate, and sufficient reserves exist with the potential downsized configuration. With the possible decrease in available power from the baseline of 2.2 kW guideline, power and shot management is critical for the baseline configuration (15 to 20 J). This is particularly true during the 100 day occultation period each year. With the downsized configurations (5 to 7 J), power management is still necessary during the occultation but is primarily limited to shot management over the polar regions. The breadboard effort has produced significant laser advances for a tight 18 month schedule and the minimum budgets available from NASA, Lockheed, and TDS. Using the NASA funds and Lockheed and TDS fixed assets budgets, the breadboard was designed, fabricated, and brought on-line with first laser light within 16 months after ATP. First laser beam was obtained on 21 April 1992 at a 5 J power level. Tests since then have been conducted at sustained, repetitive pulse levels of over 7 J and 20 Hz. This is an increase of over two or three times greater than any system previously developed from this type laser. Increased power levels and additional life tests will be accomplished in the next LAWS phase. The Lockheed LAWS design will operate in the gravity gradient mode on-orbit, and all possible instrument vibration and jitter modes have been considered. Adequate pointing stability and control is state-of-the-art technology for the critical time periods, frequency rates, and control responses required by LAWS. Lockheed

Exact solutions for a discrete unidimensional Boltzmann model satisfying all conservation laws

International Nuclear Information System (INIS)

Cornille, H.

1989-01-01

We consider a four-velocity discrete and unidimensional Boltzmann model. The mass, momentum and energy conservation laws being satisfied we can define a temperature. We report the exact positive solutions which have been found: periodic in the space and propagating or not when the time is growing, shock waves similarity solutions and (1 + 1)-dimensional solutions [fr

Rheology of serpentinite in high-temperature and low-slip-velocity regime

Science.gov (United States)

Takahashi, M.; Uehara, S.; Mizoguchi, K.; Takeda, N.; Masuda, K.

2009-12-01

This study was designed to clarify the rheology of serpentinite experimentally, related both the sliding velocity and the temperature. The frictional behavior of serpentinite is of particular interest in the study of earthquake generation processes along subducting plates and transform faults. Previous studies [Reinen et al., 1991-93] revealed that the serpentinites indicated two-mechanical behaviors at velocity-step test: ‘state-variable dominated behavior’ at relatively higher velocity (0.1-10 μm/sec) and ‘flow-dominated behavior’ at lower velocity (less than 0.1 μm/sec). Such complexity on the frictional behavior could make it complicated to forecast on the slip acceleration process from the plate motion velocity to the earthquake. Even under the room-temperature condition, those multiple behavior could be observed, thus, serpentinite can be a model substance to present a new constitutive law at the brittle-ductile transition regime. We, therefore, focus to discuss the transient behaviors of serpentinite at the velocity-step test. We used a gas-medium, high-pressure, and high-temperature triaxial testing machine belonging to the National Institute of Advanced Industrial Science and Technology (AIST), Japan. Sliding deformation was applied on the thin zone of the serpentinite gouge (1.0 g of almost pure antigorite powder) sandwiched between two alumina blocks with oblique surfaces at 30° to the axis. All experiments were carried out under a set of constant conditions, 100 MPa of the confining pressure (Ar-gas) and 30 MPa of the pore pressure (distilled water). The temperature conditions were varied from the room-temperature to 500° C, and three sliding velocity-regimes were adopted: low (0.0115 - 0.115 μm/sec), middle (0.115 - 1.15 μm/sec) and high (1.15 - 11.5 μm/sec) velocity regimes. In each velocity regime, the sliding velocity was increased or decreased in a stepwise fashion, and then we observed the transient behaviors until it reached the

Identifying coronary artery disease in asymptomatic middle-aged sportsmen : The additional value of pulse wave velocity

NARCIS (Netherlands)

Braber, Thijs L.; Prakken, Niek H J; Mosterd, Arend; Mali, Willem P Th M; Doevendans, Pieter A F M; Bots, Michiel L.; Velthuis, Birgitta K.

2015-01-01

Background: Cardiovascular screening may benefit middle-aged sportsmen, as coronary artery disease (CAD) is the main cause of exercise-related sudden cardiac death. Arterial stiffness, as measured by pulse wave velocity (PWV), may help identify sportsmen with subclinical CAD. We examined the

Generalized Faraday law derived from classical forces in a rotating frame

International Nuclear Information System (INIS)

Choi, Taeseung

2010-01-01

We show that an additional spin-dependent classical force due to the rotation of an electron spin's rest frame is essential to derive a spin-Faraday law that has the same form as the usual Faraday law. We show that the contribution of the additional spin-dependent force to the spin-Faraday law is the same as the time derivative of the spin geometric phase. With this observations, the spin-Faraday law is generalized to include both an Aharonov-Casher (AC) effect and a scalar AC effect in a unified manner.

Computing discharge using the index velocity method

Science.gov (United States)

Levesque, Victor A.; Oberg, Kevin A.

2012-01-01

techniques in which the mean cross-sectional velocity for the standard section is related to the measured index velocity. Most ratings are simple-linear regressions, but more complex ratings may be necessary in some cases. Once the rating is established, validation measurements should be made periodically. Over time, validation measurements may provide additional definition to the rating or result in the creation of a new rating. The computation of discharge is the last step in the index velocity method, and in some ways it is the most straight-forward step. This step differs little from the steps used to compute discharge records for stage-discharge gaging stations. The ratings are entered into database software used for records computation, and continuous records of discharge are computed.

P-wave velocity changes in freezing hard low-porosity rocks: a laboratory-based time-average model

Directory of Open Access Journals (Sweden)

D. Draebing

2012-10-01

Full Text Available P-wave refraction seismics is a key method in permafrost research but its applicability to low-porosity rocks, which constitute alpine rock walls, has been denied in prior studies. These studies explain p-wave velocity changes in freezing rocks exclusively due to changing velocities of pore infill, i.e. water, air and ice. In existing models, no significant velocity increase is expected for low-porosity bedrock. We postulate, that mixing laws apply for high-porosity rocks, but freezing in confined space in low-porosity bedrock also alters physical rock matrix properties. In the laboratory, we measured p-wave velocities of 22 decimetre-large low-porosity (< 10% metamorphic, magmatic and sedimentary rock samples from permafrost sites with a natural texture (> 100 micro-fissures from 25 °C to −15 °C in 0.3 °C increments close to the freezing point. When freezing, p-wave velocity increases by 11–166% perpendicular to cleavage/bedding and equivalent to a matrix velocity increase from 11–200% coincident to an anisotropy decrease in most samples. The expansion of rigid bedrock upon freezing is restricted and ice pressure will increase matrix velocity and decrease anisotropy while changing velocities of the pore infill are insignificant. Here, we present a modified Timur's two-phase-equation implementing changes in matrix velocity dependent on lithology and demonstrate the general applicability of refraction seismics to differentiate frozen and unfrozen low-porosity bedrock.

Threshold velocity for environmentally-assisted cracking in low alloy steels

International Nuclear Information System (INIS)

Wire, G.L.; Kandra, J.T.

1997-01-01

Environmentally Assisted Cracking (EAC) in low alloy steels is generally believed to be activated by dissolution of MnS inclusions at the crack tip in high temperature LWR environments. EAC is the increase of fatigue crack growth rate of up to 40 to 100 times the rate in air that occurs in high temperature LWR environments. A steady state theory developed by Combrade, suggested that EAC will initiate only above a critical crack velocity and cease below this same velocity. A range of about twenty in critical crack tip velocities was invoked by Combrade, et al., to describe data available at that time. This range was attributed to exposure of additional sulfides above and below the crack plane. However, direct measurements of exposed sulfide densities on cracked specimens were performed herein and the results rule out significant additional sulfide exposure as a plausible explanation. Alternatively, it is proposed herein that localized EAC starting at large sulfide clusters reduces the calculated threshold velocity from the value predicted for a uniform distribution of sulfides. Calculations are compared with experimental results where the threshold velocity has been measured, and the predicted wide range of threshold values for steels of similar sulfur content but varying sulfide morphology is observed. The threshold velocity decreases with the increasing maximum sulfide particle size, qualitatively consistent with the theory. The calculation provides a basis for a conservative minimum velocity threshold tied directly to the steel sulfur level, in cases where no details of sulfide distribution are known

Limits of Kirchhoff's Laws in Plasmonics.

Science.gov (United States)

Razinskas, Gary; Biagioni, Paolo; Hecht, Bert

2018-01-30

The validity of Kirchhoff's laws in plasmonic nanocircuitry is investigated by studying a junction of plasmonic two-wire transmission lines. We find that Kirchhoff's laws are valid for sufficiently small values of a phenomenological parameter κ relating the geometrical parameters of the transmission line with the effective wavelength of the guided mode. Beyond such regime, for large values of the phenomenological parameter, increasing deviations occur and the equivalent impedance description (Kirchhoff's laws) can only provide rough, but nevertheless useful, guidelines for the design of more complex plasmonic circuitry. As an example we investigate a system composed of a two-wire transmission line and a nanoantenna as the load. By addition of a parallel stub designed according to Kirchhoff's laws we achieve maximum signal transfer to the nanoantenna.

A simple law of star formation

DEFF Research Database (Denmark)

Padoan, Paolo; Haugbølle, Troels; Nordlund, Åke

2012-01-01

We show that supersonic MHD turbulence yields a star formation rate (SFR) as low as observed in molecular clouds, for characteristic values of the free-fall time divided by the dynamical time, t ff/t dyn, the Alfvénic Mach number, {\\cal M}_a, and the sonic Mach number, {\\cal M}_s. Using a very...... values of t ff/t dyn and {\\cal M}_a. (2) Decreasing values of {\\cal M}_a (stronger magnetic fields) reduce epsilonff, but only to a point, beyond which epsilonff increases with a further decrease of {\\cal M}_a. (3) For values of {\\cal M}_a characteristic of star-forming regions, epsilonff varies...... with {\\cal M}_a by less than a factor of two. We propose a simple star formation law, based on the empirical fit to the minimum epsilonff, and depending only on t ff/t dyn: epsilonff ˜ epsilonwindexp (– 1.6 t ff/t dyn). Because it only depends on the mean gas density and rms velocity, this law...

A Comparison of Military and Law Enforcement Body Armour

Science.gov (United States)

Pope, Rodney

2018-01-01

Law-enforcement officers increasingly wear body armour for protection; wearing body armour is common practice in military populations. Law-enforcement and military occupational demands are vastly different and military-styled body armour may not be suitable for law-enforcement. This study investigated differences between selected military body armour (MBA: 6.4 kg) and law-enforcement body armour (LEBA: 2.1 kg) in impacts on postural sway, vertical jump, agility, a functional movement screen (FMS), task simulations (vehicle exit; victim recovery), and subjective measures. Ten volunteer police officers (six females, four males) were randomly allocated to one of the designs on each of two days. Body armour type did not significantly affect postural sway, vertical jump, vehicle exit and 5 m sprint times, or victim recovery times. Both armour types increased sway velocity and sway-path length in the final five seconds compared to the first 5 s of a balance task. The MBA was associated with significantly slower times to complete the agility task, poorer FMS total scores, and poorer subjective ratings of performance and comfort. The LEBA was perceived as more comfortable and received more positive performance ratings during the agility test and task simulations. The impacts of MBA and LEBA differed significantly and they should not be considered interchangeable. PMID:29443905

A Comparison of Military and Law Enforcement Body Armour.

Science.gov (United States)

Orr, Robin; Schram, Ben; Pope, Rodney

2018-02-14

Law-enforcement officers increasingly wear body armour for protection; wearing body armour is common practice in military populations. Law-enforcement and military occupational demands are vastly different and military-styled body armour may not be suitable for law-enforcement. This study investigated differences between selected military body armour (MBA: 6.4 kg) and law-enforcement body armour (LEBA: 2.1 kg) in impacts on postural sway, vertical jump, agility, a functional movement screen (FMS), task simulations (vehicle exit; victim recovery), and subjective measures. Ten volunteer police officers (six females, four males) were randomly allocated to one of the designs on each of two days. Body armour type did not significantly affect postural sway, vertical jump, vehicle exit and 5 m sprint times, or victim recovery times. Both armour types increased sway velocity and sway-path length in the final five seconds compared to the first 5 s of a balance task. The MBA was associated with significantly slower times to complete the agility task, poorer FMS total scores, and poorer subjective ratings of performance and comfort. The LEBA was perceived as more comfortable and received more positive performance ratings during the agility test and task simulations. The impacts of MBA and LEBA differed significantly and they should not be considered interchangeable.

A Comparison of Military and Law Enforcement Body Armour

Directory of Open Access Journals (Sweden)

Robin Orr

2018-02-01

Full Text Available Law-enforcement officers increasingly wear body armour for protection; wearing body armour is common practice in military populations. Law-enforcement and military occupational demands are vastly different and military-styled body armour may not be suitable for law-enforcement. This study investigated differences between selected military body armour (MBA: 6.4 kg and law-enforcement body armour (LEBA: 2.1 kg in impacts on postural sway, vertical jump, agility, a functional movement screen (FMS, task simulations (vehicle exit; victim recovery, and subjective measures. Ten volunteer police officers (six females, four males were randomly allocated to one of the designs on each of two days. Body armour type did not significantly affect postural sway, vertical jump, vehicle exit and 5 m sprint times, or victim recovery times. Both armour types increased sway velocity and sway-path length in the final five seconds compared to the first 5 s of a balance task. The MBA was associated with significantly slower times to complete the agility task, poorer FMS total scores, and poorer subjective ratings of performance and comfort. The LEBA was perceived as more comfortable and received more positive performance ratings during the agility test and task simulations. The impacts of MBA and LEBA differed significantly and they should not be considered interchangeable.

Determination of groundwater flow velocity by radon measurements

International Nuclear Information System (INIS)

Hohn, E.; von Gunten, H.R.

1990-01-01

The groundwater resources of glacio-fluvial perialpine valleys are recharged significantly by the infiltration from rivers. The groundwater residence times between rivers and wells should be known in groundwater management problems. Short residence times can be estimated using radon. Radon concentrations in rivers are usually very low. Upon filtration and movement of the water in the ground, radon is picked up and its concentration increases by 2-3 orders of magnitude according to radioactive growth laws. Residence times and flow velocities can be estimated from the increasing radon concentrations measured in groundwater sampling tubes at different distances from the river. Results obtained with this method agree with the results from experiments with artificial tracers

Autism Spectrum Disorder and New Jersey Administrative Law Decisions: An Analysis of Case Law Involving Public School Students

Science.gov (United States)

Barcadepone, Michael J.

2012-01-01

The purpose of this case study was to investigate existing New Jersey case law for the special education population classified as Autism Spectrum Disorder (ASD) and analyze New Jersey Administrative Law Judge (ALJ) decisions to identify why districts win or lose cases, adding to the limited body of research in New Jersey. In addition, the purpose…

THE DEVELOPMENT OF INDONESIAN ISLAMIC LAW: A Historical Overview

Directory of Open Access Journals (Sweden)

Ahmad Yasa

2015-06-01

Full Text Available Islamic Law is a set of promoted regulations adjusting human relationship to the Creator, human being and the environment based on Islamic doctrines. The Islamic Law has been established in Indonesia and effectively implemented in Indonesian Religious Court based on Law Number 7 of 1989. The law covers the areas of marriage, inheritance, will, bequest, benefaction and alms. In addition, especially in Aceh, with its peculiar feature, Islamic Law has been applied normatively, and in several areas it has been applied based on Local Regulations. However to perform the Islamic Law, it depends on faith and piety of the members of Islam. Thereby, although the formal law in juridical manner of Islamic Law in Indonesia was justly applied in limited civil law, however the Muslim society have stepped forward in applying Islamic Law in various Islamic social institutions.

The second laws of quantum thermodynamics.

Science.gov (United States)

Brandão, Fernando; Horodecki, Michał; Ng, Nelly; Oppenheim, Jonathan; Wehner, Stephanie

2015-03-17

The second law of thermodynamics places constraints on state transformations. It applies to systems composed of many particles, however, we are seeing that one can formulate laws of thermodynamics when only a small number of particles are interacting with a heat bath. Is there a second law of thermodynamics in this regime? Here, we find that for processes which are approximately cyclic, the second law for microscopic systems takes on a different form compared to the macroscopic scale, imposing not just one constraint on state transformations, but an entire family of constraints. We find a family of free energies which generalize the traditional one, and show that they can never increase. The ordinary second law relates to one of these, with the remainder imposing additional constraints on thermodynamic transitions. We find three regimes which determine which family of second laws govern state transitions, depending on how cyclic the process is. In one regime one can cause an apparent violation of the usual second law, through a process of embezzling work from a large system which remains arbitrarily close to its original state. These second laws are relevant for small systems, and also apply to individual macroscopic systems interacting via long-range interactions. By making precise the definition of thermal operations, the laws of thermodynamics are unified in this framework, with the first law defining the class of operations, the zeroth law emerging as an equivalence relation between thermal states, and the remaining laws being monotonicity of our generalized free energies.

Cell wall pH and auxin transport velocity

Science.gov (United States)

Hasenstein, K. H.; Rayle, D.

1984-01-01

According to the chemiosmotic polar diffusion hypothesis, auxin pulse velocity and basal secretion should increase with decreasing cell wall pH. Experiments were designed to test this prediction. Avena coleoptile sections were preincubated in either fusicoccin (FC), cycloheximide, pH 4.0, or pH 8.0 buffer and subsequently their polar transport capacities were determined. Relative to controls, FC enhanced auxin (IAA) uptake while CHI and pH 8.0 buffer reduced IAA uptake. Nevertheless, FC reduced IAA pulse velocity while cycloheximide increased velocity. Additional experiments showed that delivery of auxin to receivers is enhanced by increased receiver pH. This phenomenon was overcome by a pretreatment of the tissue with IAA. Our data suggest that while acidic wall pH values facilitate cellular IAA uptake, they do not enhance pulse velocity or basal secretion. These findings are inconsistent with the chemiosmotic hypothesis for auxin transport.

Can decentralisation contribute to promoting rule-of-law structures ...

African Journals Online (AJOL)

Potchefstroom Electronic Law Journal/Potchefstroomse Elektroniese ... a country's population to exercise political influence at regional and local level. ... In addition, it raises questions regarding the effect of instruments of international law on ...

POWER-LAW AKIŞKANI İLE YAĞLANMIŞ EKSENEL KAYMALI YATAKTA BASINÇ VE HIZ DAĞILIMI

Directory of Open Access Journals (Sweden)

Muhammet YÜRÜSOY

2000-02-01

Full Text Available In this study, a slider bearing lubricated with a non-Newtonian fluid namely a Power-Law fluid is considered. First the equations of motion are derived. Perturbation methods are employed in search of approximate solutions. The simplest perturbation expansion, namely the pedestrian expansion, is used. The velocity distribution and the pressure distribution are calculated approximately. The solutions are expressed in dimensionless form for convenience. The variation of pressure and velocity with the non-Newtonian behaviour and bearing dimensions are plotted.

The efficiency of ceramic-faced metal targets at high-velocity impact

Science.gov (United States)

Tolkachev, V. F.; Konyaev, A. A.; Pakhnutova, N. V.

2017-11-01

The paper represents experimental results and engineering evaluation concerning the efficiency of composite materials to be used as an additional protection during the high- velocity interaction of a tungsten rod with a target in the velocity range of 1...5 km/s. The main parameter that characterizes the high-velocity interaction of a projectile with a layered target is the penetration depth. Experimental data, numerical simulation and engineering evaluation by modified models are used to determine the penetration depth. Boron carbide, aluminum oxide, and aluminum nickelide are applied as a front surface of targets. Based on experimental data and numerical simulation, the main characteristics of ceramics are determined, which allows composite materials to be effectively used as additional elements of protection.

The size distributions of fragments ejected at a given velocity from impact craters

Science.gov (United States)

O'Keefe, John D.; Ahrens, Thomas J.

1987-01-01

The mass distribution of fragments that are ejected at a given velocity for impact craters is modeled to allow extrapolation of laboratory, field, and numerical results to large scale planetary events. The model is semi-empirical in nature and is derived from: (1) numerical calculations of cratering and the resultant mass versus ejection velocity, (2) observed ejecta blanket particle size distributions, (3) an empirical relationship between maximum ejecta fragment size and crater diameter, (4) measurements and theory of maximum ejecta size versus ejecta velocity, and (5) an assumption on the functional form for the distribution of fragments ejected at a given velocity. This model implies that for planetary impacts into competent rock, the distribution of fragments ejected at a given velocity is broad, e.g., 68 percent of the mass of the ejecta at a given velocity contains fragments having a mass less than 0.1 times a mass of the largest fragment moving at that velocity. The broad distribution suggests that in impact processes, additional comminution of ejecta occurs after the upward initial shock has passed in the process of the ejecta velocity vector rotating from an initially downward orientation. This additional comminution produces the broader size distribution in impact ejecta as compared to that obtained in simple brittle failure experiments.

Issues concerning outer space investments in international law ...

African Journals Online (AJOL)

Issues concerning outer space investments in international law. ... Recent improvements in technology have in essence increased the viability of outer space as the next frontier for international investment and development. In addition to ... Key words: Outer Space, Investments, International Law, International Space Station ...

Geomorphic Transport Laws and the Statistics of Topography and Stratigraphy

Science.gov (United States)

Schumer, R.; Taloni, A.; Furbish, D. J.

2016-12-01

Geomorphic transport laws take the form of partial differential equations in which sediment motion is a deterministic function of slope. The addition of a noise term, representing unmeasurable, or subgrid scale autogenic forcing, reproduces scaling properties similar to those observed in topography, landforms, and stratigraphy. Here we describe a transport law that generalizes previous equations by permitting transport that is local or non-local in addition to different types of noise. More importantly, we use this transport law to link the character of sediment transport to the statistics of topography and stratigraphy. In particular, we link the origin of the Sadler effect to the evolution of the earth surface via a transport law.

EISCAT measurements of solar wind velocity and the associated level of interplanetary scintillation

Directory of Open Access Journals (Sweden)

R. A. Fallows

2002-09-01

Full Text Available A relative scintillation index can be derived from EISCAT observations of Interplanetary Scintillation (IPS usually used to study the solar wind velocity. This provides an ideal opportunity to compare reliable measurements of the solar wind velocity derived for a number of points along the line-of-sight with measurements of the overall level of scintillation. By selecting those occasions where either slow- or fast-stream scattering was dominant, it is shown that at distances from the Sun greater than 30 RS , in both cases the scintillation index fell with increasing distance as a simple power law, typically as R-1.7. The level of scintillation for slow-stream scattering is found to be 2.3 times the level for fast-stream scattering.Key words. Interplanetary physics (solar wind plasma

Business Law

DEFF Research Database (Denmark)

Föh, Kennet Fischer; Mandøe, Lene; Tinten, Bjarke

Business Law is a translation of the 2nd edition of Erhvervsjura - videregående uddannelser. It is an educational textbook for the subject of business law. The textbook covers all important topic?s within business law such as the Legal System, Private International Law, Insolvency Law, Contract law......, Instruments of debt and other claims, Sale of Goods and real estate, Charges, mortgages and pledges, Guarantees, Credit agreements, Tort Law, Product liability and Insurance, Company law, Market law, Labour Law, Family Law and Law of Inheritance....

Scaling laws for nonintercommuting cosmic string networks

International Nuclear Information System (INIS)

Martins, C.J.A.P.

2004-01-01

We study the evolution of noninteracting and entangled cosmic string networks in the context of the velocity-dependent one-scale model. Such networks may be formed in several contexts, including brane inflation. We show that the frozen network solution L∝a, although generic, is only a transient one, and that the asymptotic solution is still L∝t as in the case of ordinary (intercommuting) strings, although in the present context the universe will usually be string dominated. Thus the behavior of two strings when they cross does not seem to affect their scaling laws, but only their densities relative to the background

Conservation laws of wave action and potential enstrophy for Rossby waves in a stratified atmosphere

Science.gov (United States)

Straus, D. M.

1983-01-01

The evolution of wave energy, enstrophy, and wave motion for atmospheric Rossby waves in a variable mean flow are discussed from a theoretical and pedagogic standpoint. In the absence of mean flow gradients, the wave energy density satisfies a local conservation law, with the appropriate flow velocity being the group velocity. In the presence of mean flow variations, wave energy is not conserved, but wave action is, provided the mean flow is independent of longitude. Wave enstrophy is conserved for arbitrary variations of the mean flow. Connections with Eliassen-Palm flux are also discussed.

APPLICATION OF MULTIHOLE PRESSURE PROBE FOR RESEARCH OF COOLANT VELOCITY PROFILE IN NUCLEAR REACTOR FUEL ASSEMBLIES

Directory of Open Access Journals (Sweden)

S. M. Dmitriev

2015-01-01

Full Text Available Development of heat and mass transfer intensifiers is a major engineering task in the design of new and modernization of existing fuel assemblies. These devices create lateral mass flow of coolant. Design of intensifiers affects both the coolant mixing and the hydraulic resistance. The aim of this work is to develop a methodology of measuring coolant local velocity in the fuel assembly models with different mixing grids. To solve the problems was manufactured and calibrated multihole pressure probe. The air flow velocity measuring method with multihole pressure probe was used in the experimental studies on the coolant local hydrodynamics in fuel assemblies with mixing grids. Analysis of the coolant lateral velocity vector fields allowed to study the formation of the secondary vortex flows behind the mixing grids, and to determine the basic laws of coolant flow in experimental models. Quantitative data on the coolant flow velocity distribution obtained with a multihole pressure probe make possible to determine the magnitude of the flow lateral velocities in fuel rod gaps, as well as to determine the distance at which damping occurs during mixing. 

CONSIDERATIONS ON AMENDING AND SUPPLEMENTING LAW NO. 279/2005 ON APPRENTICESHIP AT WORK BY LAW NO. 179/2013

Directory of Open Access Journals (Sweden)

Brîndușa Oana Vartolomei

2013-11-01

Full Text Available Changes and additions made to the Law on apprenticeship contract and call into question the manner in which the Romanian legislator understands that give efficiency to this legal institutions. The scientific research aims to identify substantive changes made to the legal text by Law no. 179/2013 and to explore opportunities in the current context of national and European legislation.

Ballistic transport through graphene nanostructures of velocity and potential barriers

International Nuclear Information System (INIS)

Krstajic, P M; Vasilopoulos, P

2011-01-01

We investigate the electronic properties of graphene nanostructures when the Fermi velocity and the electrostatic potential vary in space. First, we consider the transmission T and conductance G through single and double barriers. We show that G for velocity barriers differs markedly from that for potential barriers for energies below the height of the latter and it exhibits periodic oscillations as a function of the energy for strong velocity modulation. Special attention is given to superlattices (SLs). It is shown that an applied bias can efficiently widen or shrink the allowed minibands of velocity-modulated SLs. The spectrum in the Kronig-Penney limit is periodic in the strength of the barriers. Collimation of an electron beam incident on an SL with velocity and potential barriers is present but it disappears when the potential barriers are absent. The number of additional Dirac points may change considerably if barriers and wells have sufficiently different Fermi velocities.

The species velocity of trees in Alaska

Science.gov (United States)

Morrison, B. D.; Napier, J.; de Lafontaine, G.; Heath, K.; Li, B.; Hu, F.; Greenberg, J. A.

2017-12-01

Anthropogenic climate change has motivated interest in the paleo record to enhance our knowledge about past vegetation responses to climate change and help understand potential responses in the future. Additionally, polar regions currently experience the most rapid rates of climate change globally, prompting concern over changes in the ecological composition of high latitude ecosystems. Recent analyses have attempted to construct methods to estimate a species' ability to track climate change by computing climate velocity; a measure of the rate of climate displacement across a landscape which may indicate the speed an organism must migrate to keep pace with climate change. However, a challenge to using climate velocity in understanding range shifts is a lack of species-specificity in the velocity calculations: climate velocity does not actually use any species data in its analysis. To solve the shortcomings of climate velocity in estimating species displacement rates, we computed the "species velocity" of white spruce, green and grey alder populations across the state of Alaska from the Last Glacial Maximum (LGM) to today. Species velocity represents the rate and direction a species is required to migrate to keep pace with a changing climate following the LGM. We used a species distribution model to determine past and present white spruce and alder distributions using statistically downscaled climate data at 60m. Species velocity was then derived from the change in species distribution per year by the change in distribution over Alaska (km/yr). High velocities indicate locations where the species environmental envelope is changing drastically and must disperse rapidly to survive climate change. As a result, high velocity regions are more vulnerable to distribution shifts and higher risk of local extinction. Conversely, low species velocities indicate locations where the local climate envelope is shifting relatively slowly, reducing the stress to disperse quickly

Electroviscous effects in steady fully developed flow of a power-law liquid through a cylindrical microchannel

International Nuclear Information System (INIS)

Bharti, Ram P.; Harvie, Dalton J.E.; Davidson, Malcolm R.

2009-01-01

Electroviscous effects in steady, fully developed, pressure-driven flow of power-law liquids through a uniform cylindrical microchannel have been investigated numerically by solving the Poisson-Boltzmann and the momentum equations using a finite difference method. The pipe wall is considered to have uniform surface charge density and the liquid is assumed to be a symmetric 1:1 electrolyte solution. Electroviscous resistance reduces the velocity adjacent to the wall, relative to the velocity on the axis. The effect is shown to be greater when the liquid is shear-thinning, and less when it is shear-thickening, than it is for Newtonian flow. For overlapping electrical double layers and elevated surface charge density, the electroviscous reduction in the near-wall velocity can form an almost stationary (zero shear) layer there when the liquid is shear-thinning. In that case, the liquid behaves approximately as if it is flowing through a channel of reduced diameter. The induced axial electrical field shows only a weak dependence on the power-law index with the dependence being greatest for shear-thinning liquids. This field exhibits a local maximum as surface charge density increases from zero, even though the corresponding electrokinetic resistance increases monotonically. The magnitude of the electroviscous effect on the apparent viscosity, as measured by the ratio of the apparent and physical consistency indices, decreases monotonically as the power-law index increases. Thus, overall, the electroviscous effect is stronger in shear-thinning, and weaker in shear-thickening liquids, than it is when the liquid is Newtonian.

New Technologies, New Problems, New Laws.

Science.gov (United States)

Recupero, Patricia R

2016-09-01

Forensic psychiatrists in the 21st century can expect to encounter technology-related social problems for which existing legal remedies are limited. In addition to the inadequate protection of adolescents using social media as outlined by Costello et al., current laws are often poorly suited to remedy problems such as cyberharassment, sexting among minors, and the publication of threatening or harmful communications online. Throughout history, technological developments have often preceded the introduction of new laws or the careful revision of existing laws. This pattern is evident in many of the newer social problems that involve technology, including cyberbullying, online impersonation, and revenge porn. As specialists working at the intersection of human behavior and the law, forensic psychiatrists are uniquely situated to help legal professionals and others understand the impact of internet-related problematic behaviors on victims and, perhaps, to assist in the development of new legal remedies that are better tailored to our increasingly digital society. © 2016 American Academy of Psychiatry and the Law.

Radar velocity determination using direction of arrival measurements

Energy Technology Data Exchange (ETDEWEB)

Doerry, Armin W.; Bickel, Douglas L.; Naething, Richard M.; Horndt, Volker

2017-12-19

The various technologies presented herein relate to utilizing direction of arrival (DOA) data to determine various flight parameters for an aircraft A plurality of radar images (e.g., SAR images) can be analyzed to identify a plurality of pixels in the radar images relating to one or more ground targets. In an embodiment, the plurality of pixels can be selected based upon the pixels exceeding a SNR threshold. The DOA data in conjunction with a measurable Doppler frequency for each pixel can be obtained. Multi-aperture technology enables derivation of an independent measure of DOA to each pixel based on interferometric analysis. This independent measure of DOA enables decoupling of the aircraft velocity from the DOA in a range-Doppler map, thereby enabling determination of a radar velocity. The determined aircraft velocity can be utilized to update an onboard INS, and to keep it aligned, without the need for additional velocity-measuring instrumentation.

The laws. 4. enlarged ed.

International Nuclear Information System (INIS)

1988-01-01

This issue no. 10 presents the terms and definitions valid in the field of civil defence, and the laws and regulations. There is the law relating to civil defence, of August 9, 1976, the official announcement, and the statement of legislative intent; further, the law relating to an extension of disaster services, together with the general administrative provisions concerning organisation, additional equipment, training of personnel, and financing of disaster services. The issue also presents the general administrative regulation for establishment, support, and management of civil defence, the law concerning construction and provision of shelters for the population, the general administrative regulation concerning local alarm systems and services (Warndienst-VwV) of March 31, 1981, and the act relating to the convention of May 14, 1954, for protection of cultural objects in the event of an armed conflict, (act of April 11, 1967), as well as the text of the convention itself and the protocol. (orig.) [de

Gravitational mass and Newton's universal gravitational law under relativistic conditions

International Nuclear Information System (INIS)

Vayenas, Constantinos G; Grigoriou, Dimitrios; Fokas, Athanasios

2015-01-01

We discuss the predictions of Newton's universal gravitational law when using the gravitational, m g , rather than the rest masses, m o , of the attracting particles. According to the equivalence principle, the gravitational mass equals the inertial mass, m i , and the latter which can be directly computed from special relativity, is an increasing function of the Lorentz factor, γ, and thus of the particle velocity. We consider gravitationally bound rotating composite states, and we show that the ratio of the gravitational force for gravitationally bound rotational states to the force corresponding to low (γ ≈ 1) particle velocities is of the order of (m Pl /m o ) 2 where mpi is the Planck mass (ħc/G) 1/2 . We also obtain a similar result, within a factor of two, by employing the derivative of the effective potential of the Schwarzschild geodesics of GR. Finally, we show that for certain macroscopic systems, such as the perihelion precession of planets, the predictions of this relativistic Newtonian gravitational law differ again by only a factor of two from the predictions of GR. (paper)

Flow of power-law fluids in fixed beds of cylinders or spheres

KAUST Repository

Singh, John P.

2012-10-29

An ensemble average of the equations of motion for a Newtonian fluid over particle configurations in a dilute fixed bed of spheres or cylinders yields Brinkman\\'s equations of motion, where the disturbance velocity produced by a test particle is influenced by the Newtonian fluid stress and a body force representing the linear drag on the surrounding particles. We consider a similar analysis for a power-law fluid where the stress τ is related to the rate of strain e by τ = 2m en-1e, where m and n are constants. In this case, the ensemble-averaged momentum equation includes a body force resulting from the nonlinear drag exerted on the surrounding particles, a power-law stress associated with the disturbance velocity of the test particle, and a stress term that is linear with respect to the test particle\\'s disturbance velocity. The latter term results from the interaction of the test particle\\'s velocity disturbance with the random straining motions produced by the neighbouring particles and is important only in shear-thickening fluids where the velocity disturbances of the particles are long-ranged. The solutions to these equations using scaling analyses for dilute beds and numerical simulations using the finite element method are presented. We show that the drag force acting on a particle in a fixed bed can be written as a function of a particle-concentration-dependent length scale at which the fluid velocity disturbance produced by a particle is modified by hydrodynamic interactions with its neighbours. This is also true of the drag on a particle in a periodic array where the length scale is the lattice spacing. The effects of particle interactions on the drag in dilute arrays (periodic or random) of cylinders and spheres in shear-thickening fluids is dramatic, where it arrests the algebraic growth of the disturbance velocity with radial position when n≥ 1 for cylinders and n≥ 2 for spheres. For concentrated random arrays of particles, we adopt an

WORLD TRADE ORGANIZATION: Observations on China's Rule of Law Reforms

National Research Council Canada - National Science Library

Westin, Susan

2002-01-01

.... In addition, China has made a substantial number of other WTO commitments related to the rule of law areas of transparency, judicial review, uniform enforcement of laws, and nondiscriminatory treatment...

Superconducting RF for Low-Velocity and Intermediate-Velocity Beams

CERN Document Server

Grimm, Terry L

2005-01-01

Existing superconducting radio frequency (SRF) linacs are used to accelerate ions (protons through uranium) with velocities less than about 15% the speed of light, or electrons with velocities approximately equal to the speed of light. In the last ten years, prototype SRF cavities have completely covered the remaining range of velocities. They have demonstrated that SRF linacs will be capable of accelerating electrons from rest up to the speed of light, and ions from less than 1% up to the speed of light. When the Spallation Neutron Source is operational, SRF ion linacs will have covered the full range of velocities except for v/c ~ 0.15 to v/c ~ 0.5. A number of proposed projects (RIA, EURISOL) would span the latter range of velocities. Future SRF developments will have to address the trade-offs associated with a number of issues, including high gradient operation, longitudinal and transverse acceptance, microphonics, Lorentz detuning, operating temperature, cryogenic load, number of gaps or cells per cavity...

The development of international law through the unauthorised ...

African Journals Online (AJOL)

The law, including international law, is subject to continuous change. It can be adapted to changing circumstances through formal amendments of or additions to existing norms and practices. It can also be changed through the conduct of international institutions that is not within their legally defined competencies, provided ...

Homotopy Perturbation Method for Creeping Flow of Non-Newtonian Power-Law Nanofluid in a Nonuniform Inclined Channel with Peristalsis

Science.gov (United States)

Abou-zeid, Mohamed Y.; Mohamed, Mona A. A.

2017-09-01

This article is an analytic discussion for the motion of power-law nanofluid with heat transfer under the effect of viscous dissipation, radiation, and internal heat generation. The governing equations are discussed under the assumptions of long wavelength and low Reynolds number. The solutions for temperature and nanoparticle profiles are obtained by using homotopy perturbation method. Results for the behaviours of the axial velocity, temperature, and nanoparticles as well as the skin friction coefficient, reduced Nusselt number, and Sherwood number with other physical parameters are obtained graphically and analytically. It is found that as the power-law exponent increases, both the axial velocity and temperature increase, whereas nanoparticles decreases. These results may have applicable importance in the research discussions of nanofluid flow in channels with small diameters under the effect of different temperature distributions.

Critical velocities in He II for independently varied superfluid and normal fluid velocities

International Nuclear Information System (INIS)

Baehr, M.L.

1984-01-01

Experiments were performed to measure the critical velocity in pure superflow and compare to the theoretical prediction; to measure the first critical velocity for independently varied superfluid and normal fluid velocities; and to investigate the propagation of the second critical velocity from the thermal counterflow line through the V/sub n/,-V/sub s/ quadrant. The experimental apparatus employed a thermal counterflow heater to adjust the normal fluid velocity, a fountain pump to vary the superfluid velocity, and a level sensing capacitor to measure the superfluid velocity. The results of the pure superfluid critical velocity measurements indicate that this velocity is temperature independent contrary to Schwarz's theory. It was found that the first critical velocity for independently varied V/sub n/ and V/sub s/ could be described by a linear function of V/sub n/ and was otherwise temperature independent. It was found that the second critical velocity could only be distinguished near the thermal counterflow line

Countering abuses at the granting of additional measures of state support to families with children: the possibilities of the legislator and law enforcement practice experience

Directory of Open Access Journals (Sweden)

Oleg S. Kurchenko

2018-01-01

Full Text Available The subject of the article is abuses at the granting of additional measures of state support to families with children and measures of its preventionThe purpose of the article is to analyze legal rules governing the provision of additional measures of state support for families with children, to determine their completeness and adequacy for countering abuses in this area.Characteristic of the problem field. The implementation of the legislation on additional measures of state support for families with children, has proved to be connected with widespread attempts to use the maternity (family capital by the persons who do not have the right, or to use it contrary to the restrictions established by law. Analyzed legislation has shortcomings that create the conditions for illegal actions.Methodology. Both general scientific methods (analysis, synthesis, description and special scientific methods (comparative-legal and formal-legal methods were used in the research process .Results. Countering abuses requires improvement (changes and additions of the law governing the provision of additional measures of state support for families with children. Refinement and extension of powers of the Pension Fund’s of the Russian Federation bodies in this area, however, inevitably entails an increase in the number of organizational actions performed by these bodies when considering applications of the entitled persons. The flip side of strengthening the fight against illegal actions in this sphere can also be the limitation of the possibilities of the entitled persons and the extension of discretion of authorized bodies. When the effective legislative means are absent the judicial practice plays a prominent role in preventing the illegal use of maternity (family capital. In particular, the qualification of improvement of housing conditions as a necessary result of the contract of purchase and sale of real estate became one of the obstacles to illegal receipt of

Environmental law

International Nuclear Information System (INIS)

Bender, B.; Sparwasser, R.

1988-01-01

Environmental law is discussed exhaustively in this book. Legal and scientific fundamentals are taken into account, a systematic orientation is given, and hints for further information are presented. The book covers general environmental law, plan approval procedures, protection against nuisances, atomic law and radiation protection law, water protection law, waste management law, laws on chemical substances, conservation law. (HSCH) [de

FACTUAL INDETERMINACY IN INTERNATIONAL TAX LAW

Directory of Open Access Journals (Sweden)

B. Bogenschneider

2016-01-01

Full Text Available Legal indeterminacy comes in a variety of forms identified here as: (i general legal indeterminacy; (ii factual indeterminacy; and (iii Mach/Feyerabend factual indeterminacy. The concept of general “legal indeterminacy” refers to problems in legal interpretation and has been extensively studied. “Factual indeterminacy” refers to the indeterminacy of facts as a matter of tax law when derived from separately indeterminate fields of law. “Mach/ Feyerabend factual indeterminacy” refers to fact words as derived from legal theory which provide the content for legal interpretation. The “facts” in tax law are not transcendent to law; in addition, the “fact” words of tax law cannot be simply imported from the field of economics. The incremental question of the origins of theory (as discussed by Karl Popper and Albert Einstein is also analyzed here. The theory of tax law originates with “sympathy with experience” or “intellectual love” (tr. Einfühlung of tax law by lawyers as reflected in the special heuristics and practices of the profession. Legal theory accordingly functions in similar fashion to scientific theory where a particular legal theory can be falsified (qua Popper or understood in pluralistic terms by incorporating auxiliary ideas.

International Law and the Society of Nations: An Introduction to Public International Law in the 1990s. Cases and Materials.

Science.gov (United States)

King, Jason Scott, Ed.; Scurti, Jason, Ed.; And Others

This casebook on international law was developed by high school students around the globe and emphasizes the important role that students can play in furthering international law education. The text provides teachers and students with a summary review of 25 major cases heard by the International Court of Justice, along with additional materials.…

Mean Velocity vs. Mean Propulsive Velocity vs. Peak Velocity: Which Variable Determines Bench Press Relative Load With Higher Reliability?

Science.gov (United States)

García-Ramos, Amador; Pestaña-Melero, Francisco L; Pérez-Castilla, Alejandro; Rojas, Francisco J; Gregory Haff, G

2018-05-01

García-Ramos, A, Pestaña-Melero, FL, Pérez-Castilla, A, Rojas, FJ, and Haff, GG. Mean velocity vs. mean propulsive velocity vs. peak velocity: which variable determines bench press relative load with higher reliability? J Strength Cond Res 32(5): 1273-1279, 2018-This study aimed to compare between 3 velocity variables (mean velocity [MV], mean propulsive velocity [MPV], and peak velocity [PV]): (a) the linearity of the load-velocity relationship, (b) the accuracy of general regression equations to predict relative load (%1RM), and (c) the between-session reliability of the velocity attained at each percentage of the 1-repetition maximum (%1RM). The full load-velocity relationship of 30 men was evaluated by means of linear regression models in the concentric-only and eccentric-concentric bench press throw (BPT) variants performed with a Smith machine. The 2 sessions of each BPT variant were performed within the same week separated by 48-72 hours. The main findings were as follows: (a) the MV showed the strongest linearity of the load-velocity relationship (median r = 0.989 for concentric-only BPT and 0.993 for eccentric-concentric BPT), followed by MPV (median r = 0.983 for concentric-only BPT and 0.980 for eccentric-concentric BPT), and finally PV (median r = 0.974 for concentric-only BPT and 0.969 for eccentric-concentric BPT); (b) the accuracy of the general regression equations to predict relative load (%1RM) from movement velocity was higher for MV (SEE = 3.80-4.76%1RM) than for MPV (SEE = 4.91-5.56%1RM) and PV (SEE = 5.36-5.77%1RM); and (c) the PV showed the lowest within-subjects coefficient of variation (3.50%-3.87%), followed by MV (4.05%-4.93%), and finally MPV (5.11%-6.03%). Taken together, these results suggest that the MV could be the most appropriate variable for monitoring the relative load (%1RM) in the BPT exercise performed in a Smith machine.

Additive and polynomial representations

CERN Document Server

Krantz, David H; Suppes, Patrick

1971-01-01

Additive and Polynomial Representations deals with major representation theorems in which the qualitative structure is reflected as some polynomial function of one or more numerical functions defined on the basic entities. Examples are additive expressions of a single measure (such as the probability of disjoint events being the sum of their probabilities), and additive expressions of two measures (such as the logarithm of momentum being the sum of log mass and log velocity terms). The book describes the three basic procedures of fundamental measurement as the mathematical pivot, as the utiliz

Law enforcement suicide: a national analysis.

Science.gov (United States)

Violanti, John M; Robinson, Cynthia F; Shen, Rui

2013-01-01

Previous research suggests that there is an elevated risk of suicide among workers within law enforcement occupations. The present study examined the proportionate mortality for suicide in law enforcement in comparison to the US working population during 1999, 2003-2004, and 2007, based on Centers for Disease Control and Prevention's National Institute for Occupational Safety and Health National Occupational Mortality Surveillance data. We analyzed data for all law enforcement occupations and focused on two specific law enforcement occupational categories-detectives/criminal investigators/ police and corrections officers. Suicides were also explored by race, gender and ethnicity. The results of the study showed proportionate mortality ratios (PMRs) for suicide were significantly high for all races and sexes combined (all law enforcement--PMR = 169, 95% CI = 150-191, p law enforcement combined category, and a similarly high PMR was found among Hispanic detectives/criminal investigators/police (PMR = 388, p < 0.01, 95% CI = 168-765). There were small numbers of deaths among female and African American officers. The results included significantly increased risk for suicide among detectives/criminal investigators/police and corrections officers, which suggests that additional study could provide better data to inform us for preventive action.

Experimental study of the positive leader velocity as a function of the current in the initial and final-jump phases of a spark discharge

International Nuclear Information System (INIS)

Andreev, A. G.; Bazelyan, E. M.; Bulatov, M. U.; Kuzhekin, I. P.; Makalsky, L. M.; Sukharevskij, D. I.; Syssoev, V. S.

2008-01-01

A positive leader in air at gap lengths of up to 8 m was studied experimentally on an open experimental stand. The voltage source was a 6-MV pulsed voltage generator or an artificial charged aerosol cloud. The dependence of the leader velocity on the current in the range 0.2-8 A was determined by simultaneously recording the optical picture and electric parameters of the discharge. Particular attention was paid to the final-jump phase of the discharge, when the gap was completely bridged by the streamer zone of the leader. It is shown that the character of the dependence of the leader velocity on the current in this phase remains unchanged; hence, the final-jump phase can be used in experiments in which the current has to be varied within a wide range. For this purpose, one can use a damping resistance, which is inefficient in the initial phase. The parameters of the power-law dependence of the leader velocity on the current at currents of a few amperes are established reliably. It is found that the power-law dependence with constant parameters is inapplicable to calculate the leader velocity at currents of about 0.1 A, which correspond to the lower limit of the leader viability.

UNIDROITED POSITION AS A SOURCE OF CONTRACT LAW IN THE FUTURE OF INDONESIAN CONTRACT LAW AMANDEMENT

OpenAIRE

N. Ike Kusmiati

2018-01-01

[Unidroited Position As A Source Of Contract Law In The Future Of Indonesian Contract Law Amandement] Business transaction often faced the issue of ensuring that the rights and obligation are fulfilled as the agreement as agreed, especially when facing the difficulties of the rights and obligation of the parties due to different legal system between countries. Thereore, to answer the problems  the parties will seek legal sources, namely book III of the Civil Code in addition to studying and u...

Environmental law

International Nuclear Information System (INIS)

Ketteler, G.; Kippels, K.

1988-01-01

In section I 'Basic principles' the following topics are considered: Constitutional-legal aspects of environmental protection, e.g. nuclear hazards and the remaining risk; European environmental law; international environmental law; administrative law, private law and criminal law relating to the environment; basic principles of environmental law, the instruments of public environmental law. Section II 'Special areas of law' is concerned with the law on water and waste, prevention of air pollution, nature conservation and care of the countryside. Legal decisions and literature up to June 1988 have been taken into consideration. (orig./RST) [de

Explosive Yield Estimation using Fourier Amplitude Spectra of Velocity Histories

Science.gov (United States)

Steedman, D. W.; Bradley, C. R.

2016-12-01

The Source Physics Experiment (SPE) is a series of explosive shots of various size detonated at varying depths in a borehole in jointed granite. The testbed includes an extensive array of accelerometers for measuring the shock environment close-in to the explosive source. One goal of SPE is to develop greater understanding of the explosion phenomenology in all regimes: from near-source, non-linear response to the far-field linear elastic region, and connecting the analyses from the respective regimes. For example, near-field analysis typically involves review of kinematic response (i.e., acceleration, velocity and displacement) in the time domain and looks at various indicators (e.g., peaks, pulse duration) to facilitate comparison among events. Review of far-field data more often is based on study of response in the frequency domain to facilitate comparison of event magnitudes. To try to "bridge the gap" between approaches, we have developed a scaling law for Fourier amplitude spectra of near-field velocity histories that successfully collapses data from a wide range of yields (100 kg to 5000 kg) and range to sensors in jointed granite. Moreover, we show that we can apply this scaling law to data from a new event to accurately estimate the explosive yield of that event. This approach presents a new way of working with near-field data that will be more compatible with traditional methods of analysis of seismic data and should serve to facilitate end-to-end event analysis. The goal is that this new approach to data analysis will eventually result in improved methods for discrimination of event type (i.e., nuclear or chemical explosion, or earthquake) and magnitude.

Friction law and hysteresis in granular materials

Science.gov (United States)

DeGiuli, E.; Wyart, M.

2017-08-01

The macroscopic friction of particulate materials often weakens as the flow rate is increased, leading to potentially disastrous intermittent phenomena including earthquakes and landslides. We theoretically and numerically study this phenomenon in simple granular materials. We show that velocity weakening, corresponding to a nonmonotonic behavior in the friction law, μ(I), is present even if the dynamic and static microscopic friction coefficients are identical, but disappears for softer particles. We argue that this instability is induced by endogenous acoustic noise, which tends to make contacts slide, leading to faster flow and increased noise. We show that soft spots, or excitable regions in the materials, correspond to rolling contacts that are about to slide, whose density is described by a nontrivial exponent θs. We build a microscopic theory for the nonmonotonicity of μ(I), which also predicts the scaling behavior of acoustic noise, the fraction of sliding contacts χ, and the sliding velocity, in terms of θs. Surprisingly, these quantities have no limit when particles become infinitely hard, as confirmed numerically. Our analysis rationalizes previously unexplained observations and makes experimentally testable predictions.

A Kinematic Conservation Law in Free Surface Flow

OpenAIRE

Gavrilyuk , Sergey; Kalisch , Henrik; Khorsand , Zahra

2015-01-01

The Green-Naghdi system is used to model highly nonlinear weakly dispersive waves propagating at the surface of a shallow layer of a perfect fluid. The system has three associated conservation laws which describe the conservation of mass, momentum, and energy due to the surface wave motion. In addition, the system features a fourth conservation law which is the main focus of this note. It will be shown how this fourth conservation law can be interpreted in terms of a concrete kinematic quanti...

3-D Velocity Estimation for Two Planes in vivo

DEFF Research Database (Denmark)

Holbek, Simon; Pihl, Michael Johannes; Ewertsen, Caroline

2014-01-01

3-D velocity vectors can provide additional flow information applicable for diagnosing cardiovascular diseases e.g. by estimating the out-of-plane velocity component. A 3-D version of the Transverse Oscillation (TO) method has previously been used to obtain this information in a carotid flow...... and stored on the experimental scanner SARUS. The full 3-D velocity profile can be created and examined at peak-systole and end-diastole without ECG gating in two planes. Maximum out-of-plane velocities for the three peak-systoles and end-diastoles were 68.5 5.1 cm/s and 26.3 3.3 cm/s, respectively....... In the longitudinal plane, average maximum peak velocity in flow direction was 65.2 14.0 cm/s at peak-systole and 33.6 4.3 cm/s at end-diastole. A commercial BK Medical ProFocus UltraView scanner using a spectral estimator gave 79.3 cm/s and 14.6 cm/s for the same volunteer. This demonstrates that real-time 3-D...

Velocity statistics for interacting edge dislocations in one dimension from Dyson's Coulomb gas model.

Science.gov (United States)

Jafarpour, Farshid; Angheluta, Luiza; Goldenfeld, Nigel

2013-10-01

The dynamics of edge dislocations with parallel Burgers vectors, moving in the same slip plane, is mapped onto Dyson's model of a two-dimensional Coulomb gas confined in one dimension. We show that the tail distribution of the velocity of dislocations is power law in form, as a consequence of the pair interaction of nearest neighbors in one dimension. In two dimensions, we show the presence of a pairing phase transition in a system of interacting dislocations with parallel Burgers vectors. The scaling exponent of the velocity distribution at effective temperatures well below this pairing transition temperature can be derived from the nearest-neighbor interaction, while near the transition temperature, the distribution deviates from the form predicted by the nearest-neighbor interaction, suggesting the presence of collective effects.

Microseismic Velocity Imaging of the Fracturing Zone

Science.gov (United States)

Zhang, H.; Chen, Y.

2015-12-01

Hydraulic fracturing of low permeability reservoirs can induce microseismic events during fracture development. For this reason, microseismic monitoring using sensors on surface or in borehole have been widely used to delineate fracture spatial distribution and to understand fracturing mechanisms. It is often the case that the stimulated reservoir volume (SRV) is determined solely based on microseismic locations. However, it is known that for some fracture development stage, long period long duration events, instead of microseismic events may be associated. In addition, because microseismic events are essentially weak and there exist different sources of noise during monitoring, some microseismic events could not be detected and thus located. Therefore the estimation of the SRV is biased if it is solely determined by microseismic locations. With the existence of fluids and fractures, the seismic velocity of reservoir layers will be decreased. Based on this fact, we have developed a near real time seismic velocity tomography method to characterize velocity changes associated with fracturing process. The method is based on double-difference seismic tomography algorithm to image the fracturing zone where microseismic events occur by using differential arrival times from microseismic event pairs. To take into account varying data distribution for different fracking stages, the method solves the velocity model in the wavelet domain so that different scales of model features can be obtained according to different data distribution. We have applied this real time tomography method to both acoustic emission data from lab experiment and microseismic data from a downhole microseismic monitoring project for shale gas hydraulic fracturing treatment. The tomography results from lab data clearly show the velocity changes associated with different rock fracturing stages. For the field data application, it shows that microseismic events are located in low velocity anomalies. By

Impacts of Deflection Nose on Ballistic Trajectory Control Law

Directory of Open Access Journals (Sweden)

Bo Zhang

2014-01-01

Full Text Available The deflection of projectile nose is aimed at changing the motion of the projectile in flight with the theory of motion control and changing the exterior ballistics so as to change its range and increase its accuracy. The law of external ballistics with the deflectable nose is considered as the basis of the design of a flight control system and an important part in the process of projectile development. Based on the existing rigid external ballistic model, this paper establishes an external ballistic calculation model for deflectable nose projectile and further establishes the solving programs accordingly. Different angle of attack, velocity, coefficients of lift, resistance, and moment under the deflection can be obtained in this paper based on the previous experiments and emulation researches. In the end, the author pointed out the laws on the impaction of external ballistic trajectory by the deflection of nose of the missile.

Scaling laws for radial foil bearings

Science.gov (United States)

Honavara Prasad, Srikanth

The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

Diffraction imaging and velocity analysis using oriented velocity continuation

KAUST Repository

Decker, Luke

2014-08-05

We perform seismic diffraction imaging and velocity analysis by separating diffractions from specular reflections and decomposing them into slope components. We image slope components using extrapolation in migration velocity in time-space-slope coordinates. The extrapolation is described by a convection-type partial differential equation and implemented efficiently in the Fourier domain. Synthetic and field data experiments show that the proposed algorithm is able to detect accurate time-migration velocities by automatically measuring the flatness of events in dip-angle gathers.

Multiple Model Adaptive Attitude Control of LEO Satellite with Angular Velocity Constraints

Science.gov (United States)

Shahrooei, Abolfazl; Kazemi, Mohammad Hosein

2018-04-01

In this paper, the multiple model adaptive control is utilized to improve the transient response of attitude control system for a rigid spacecraft. An adaptive output feedback control law is proposed for attitude control under angular velocity constraints and its almost global asymptotic stability is proved. The multiple model adaptive control approach is employed to counteract large uncertainty in parameter space of the inertia matrix. The nonlinear dynamics of a low earth orbit satellite is simulated and the proposed control algorithm is implemented. The reported results show the effectiveness of the suggested scheme.

Velocity and Magnetic Compressions in FEL Drivers

CERN Document Server

Serafini, L

2005-01-01

We will compare merits and issues of these two techniques suitable for increasing the peak current of high brightness electron beams. The typical range of applicability is low energy for the velocity bunching and middle to high energy for magnetic compression. Velocity bunching is free from CSR effects but requires very high RF stability (time jitters), as well as a dedicated additional focusing and great cure in the beam transport: it is very well understood theoretically and numerical simulations are pretty straightforward. Several experiments of velocity bunching have been performed in the past few years: none of them, nevertheless, used a photoinjector designed and optimized for that purpose. Magnetic compression is a much more consolidated technique: CSR effects and micro-bunch instabilities are its main drawbacks. There is a large operational experience with chicanes used as magnetic compressors and their theoretical understanding is quite deep, though numerical simulations of real devices are still cha...

Law Studies

Directory of Open Access Journals (Sweden)

G. P. Tolstopiatenko

2014-01-01

Full Text Available At the origin of the International Law Department were such eminent scientists, diplomats and teachers as V.N. Durdenevsky, S.B. Krylov and F.I. Kozhevnikov. International law studies in USSR and Russia during the second half of the XX century was largely shaped by the lawyers of MGIMO. They had a large influence on the education in the international law in the whole USSR, and since 1990s in Russia and other CIS countries. The prominence of the research of MGIMO international lawyers was due to the close connections with the international practice, involving international negotiations in the United Nations and other international fora, diplomatic conferences and international scientific conferences. This experience is represented in the MGIMO handbooks on international law, which are still in demand. The Faculty of International Law at MGIMO consists of seven departments: Department of International Law, Department of Private International and Comparative Law; Department of European Law; Department of Comparative Constitutional Law; Department of Administrative and Financial Law; Department of Criminal Law, Department Criminal Procedure and Criminalistics. Many Russian lawyers famous at home and abroad work at the Faculty, contributing to domestic and international law studies. In 1947 the Academy of Sciences of the USSR published "International Law" textbook which was the first textbook on the subject in USSR. S.B. Krylov and V.N. Durdenevsky were the authors and editors of the textbook. First generations of MGIMO students studied international law according to this textbook. All subsequent books on international law, published in the USSR, were based on the approach to the teaching of international law, developed in the textbook by S.B. Krylov and V.N. Durdenevsky. The first textbook of international law with the stamp of MGIMO, edited by F.I. Kozhevnikov, was published in 1964. This textbook later went through five editions in 1966, 1972

Combining Newton's second law and de Broglie's particle-wave duality

Science.gov (United States)

Hill, James M.

2018-03-01

All matter can exhibit wave-like behaviour, and Louis de Broglie first predicted light to display the dual characteristics as both a collection of particles, called photons, or in some respects as a wave. The particle velocity is the group velocity of the wave, and if the particle velocity ug is subluminal then the associated wave or phase velocity up through the de Broglie relation ugup =c2 is necessarily superluminal. This is believed not to contradict the fact that information cannot be carried faster than the velocity of light c because the wave phase is supposed to carry no energy. However, the superluminal phase velocity may well be physically significant, and here we propose that the sub particle world and the super wave world might be equally important, and that each might exert an influence on the other, such that any mechanical equations must not only be Lorentz invariant but they must also be invariant under the transformation connecting the sub and super worlds. Following this approach, Einstein's equation E =mc2 becomes simply E = (m +m‧)c2 , where m and m‧ are masses given by Einstein expressions arising from the perceived sub and superluminal velocities ug and up respectively. This modification, although superficially simple, results from non-conventional physics and gives rise to an extension of Newton's second law, that might well account for the extra energy and mass that is known to exist in the universe, and referred to as dark energy and dark matter. An explicit solution for photons and light predicts a non-zero photon rest-mass m0 = hν / 2c2 , where h is Planck's constant and ν is the light frequency. Interestingly, the associated energy of this mass is the zero-point energy, believed to be the lowest energy that a quantum mechanical system may possess.

A sextupole-magnet as variable velocity selector for paramagnetic atomic beams in the thermal range

International Nuclear Information System (INIS)

Spindler, G.; Ebinghaus, H.; Steffens, E.

1974-01-01

The possibility of employing a sextupole-magnet as a velocity selector on account of its velocity dependent focusing properties for paramagnetic atomic beams is investigated. In comparison with a traditional velocity selector with rotating disks, a sextupole-magnet as velocity selector has the advantage of additional focusing and polarizing the atomic beam. Moreover it suppresses polymer molecules without an effective magnetic momentum of the electronic shell

(ICSID) ADDITIONAL FACILITY IN INTERNA

African Journals Online (AJOL)

Fr. Ikenga

... which is adopted by Article 5 of the Additional Facility Rules to guide the ... B, Barrister at Law, e-mail: kcezeibe@yahoo.com; Phone 08033950631 and .... revision and annulment which are internally available under the Washington ...

ExtLaw_H18: Extinction law code

Science.gov (United States)

Hosek, Matthew W., Jr.; Lu, Jessica R.; Anderson, Jay; Do, Tuan; Schlafly, Edward F.; Ghez, Andrea M.; Clarkson, William I.; Morris, Mark R.; Albers, Saundra M.

2018-03-01

ExtLaw_H18 generates the extinction law between 0.8 - 2.2 microns. The law is derived using the Westerlund 1 (Wd1) main sequence (A_Ks 0.6 mag) and Arches cluster field Red Clump at the Galactic Center (A_Ks 2.7 mag). To derive the law a Wd1 cluster age of 5 Myr is assumed, though changing the cluster age between 4 Myr - 7 Myr has no effect on the law. This extinction law can be applied to highly reddened stellar populations that have similar foreground material as Wd1 and the Arches RC, namely dust from the spiral arms of the Milky Way in the Galactic Plane.

International Satellite Law

Science.gov (United States)

von der Dunk, Frans

2017-07-01

International space law is generally considered to be a branch of public international law. In that sense, it constitutes a "subset of rules, rights and obligations of states within the latter specifically related to outer space and activities in or with respect to that realm." Dealing with an inherently international realm, much of it had been developed in the context of the United Nations, where the key treaties are even adhered to by all major space-faring countries. In addition, other sources—including not only customary international law but also such disputed concepts as "soft law" and political guidelines and recommendations—also contributed to the development of a general framework legal regime for all of mankind's endeavors in or with respect to outer space. Originally, this predominantly included scientific and military/security-related activities, but with the ongoing development of technology and a more practical orientation, it increasingly came to encompass many more civilian and, ultimately, even commercial activities, largely through downstream applications originating from or depending on space technology and space activities. Important here are the overarching, usually more theoretical aspects of international space law, which include how it was developed or continues to be developed, what special roles do "soft law" or the military aspects of space activities play in this regard, and how do national space laws (also) serve as a tool for interpretation of international space law. Also important is the special category of launches and other space operations in the sense of moving space objects safely into, through and—if applicable—back from outer space. Without such operations, space activities would be impossible, yet they bring with them special concerns; for instance, in terms of liability, the creation of space debris and even the legal status and possible commercialization of natural resources produced from celestial bodies. Finally

Influence of polymer additives on turbulent energy cascading in forced homogeneous isotropic turbulence studied by direct numerical simulations

International Nuclear Information System (INIS)

Li Feng-Chen; Cai Wei-Hua; Zhang Hong-Na; Wang Yue

2012-01-01

Direct numerical simulations (DNS) were performed for the forced homogeneous isotropic turbulence (FHIT) with/without polymer additives in order to elaborate the characteristics of the turbulent energy cascading influenced by drag-reducing effects. The finite elastic non-linear extensibility-Peterlin model (FENE-P) was used as the conformation tensor equation for the viscoelastic polymer solution. Detailed analyses of DNS data were carried out in this paper for the turbulence scaling law and the topological dynamics of FHIT as well as the important turbulent parameters, including turbulent kinetic energy spectra, enstrophy and strain, velocity structure function, small-scale intermittency, etc. A natural and straightforward definition for the drag reduction rate was also proposed for the drag-reducing FHIT based on the decrease degree of the turbulent kinetic energy. It was found that the turbulent energy cascading in the FHIT was greatly modified by the drag-reducing polymer additives. The enstrophy and the strain fields in the FHIT of the polymer solution were remarkably weakened as compared with their Newtonian counterparts. The small-scale vortices and the small-scale intermittency were all inhibited by the viscoelastic effects in the FHIT of the polymer solution. However, the scaling law in a fashion of extended self-similarity for the FHIT of the polymer solution, within the presently simulated range of Weissenberg numbers, had no distinct differences compared with that of the Newtonian fluid case

Joint Criminal Enterprise: The ICTY’s Contentious Addition to International Law

DEFF Research Database (Denmark)

Carlson, Kerstin Bree

2008-01-01

The ICTY does not merely represent a historical stage in the development of international criminal justice which can now be put aside and left to legal historians. It also has a lasting impact, due to the fact that its Rules of Procedure and Evidence are judge-made law, tested in the fire of court...... practice and frequently amended to take the latest developments into account. Finally, with the arrest of Slobodan Karadžić, a new chapter has been opened for the Court. This volume thus provides not only an account of all the debates revolving around the proper role of international criminal justice...... and a contribution to the developing academic discipline of “transitional justice”; it also opens up a perspective to the International Criminal Court and asks what procedural legacy the ad hoc tribunals for Yugoslavia and Ruanda provide for the future of international criminal procedure....

No evidence for bulk velocity from type Ia supernovae

Energy Technology Data Exchange (ETDEWEB)

Huterer, Dragan; Shafer, Daniel L. [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI 48109 (United States); Schmidt, Fabian, E-mail: huterer@umich.edu, E-mail: dlshafer@umich.edu, E-mail: fabians@mpa-garching.mpg.de [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching (Germany)

2015-12-01

We revisit the effect of peculiar velocities on low-redshift type Ia supernovae. Velocities introduce an additional guaranteed source of correlations between supernova magnitudes that should be considered in all analyses of nearby supernova samples but has largely been neglected in the past. Applying a likelihood analysis to the latest compilation of nearby supernovae, we find no evidence for the presence of these correlations, although, given the significant noise, the data is also consistent with the correlations predicted for the standard ΛCDM model. We then consider the dipolar component of the velocity correlations—the frequently studied ''bulk velocity''—and explicitly demonstrate that including the velocity correlations in the data covariance matrix is crucial for drawing correct and unambiguous conclusions about the bulk flow. In particular, current supernova data is consistent with no excess bulk flow on top of what is expected in ΛCDM and effectively captured by the covariance. We further clarify the nature of the apparent bulk flow that is inferred when the velocity covariance is ignored. We show that a significant fraction of this quantity is expected to be noise bias due to uncertainties in supernova magnitudes and not any physical peculiar motion.

No evidence for bulk velocity from type Ia supernovae

International Nuclear Information System (INIS)

Huterer, Dragan; Shafer, Daniel L.; Schmidt, Fabian

2015-01-01

We revisit the effect of peculiar velocities on low-redshift type Ia supernovae. Velocities introduce an additional guaranteed source of correlations between supernova magnitudes that should be considered in all analyses of nearby supernova samples but has largely been neglected in the past. Applying a likelihood analysis to the latest compilation of nearby supernovae, we find no evidence for the presence of these correlations, although, given the significant noise, the data is also consistent with the correlations predicted for the standard ΛCDM model. We then consider the dipolar component of the velocity correlations—the frequently studied ''bulk velocity''—and explicitly demonstrate that including the velocity correlations in the data covariance matrix is crucial for drawing correct and unambiguous conclusions about the bulk flow. In particular, current supernova data is consistent with no excess bulk flow on top of what is expected in ΛCDM and effectively captured by the covariance. We further clarify the nature of the apparent bulk flow that is inferred when the velocity covariance is ignored. We show that a significant fraction of this quantity is expected to be noise bias due to uncertainties in supernova magnitudes and not any physical peculiar motion

Pulsatile blood flow, shear force, energy dissipation and Murray's Law

Directory of Open Access Journals (Sweden)

Bengtsson Hans-Uno

2006-08-01

Full Text Available Abstract Background Murray's Law states that, when a parent blood vessel branches into daughter vessels, the cube of the radius of the parent vessel is equal to the sum of the cubes of the radii of daughter blood vessels. Murray derived this law by defining a cost function that is the sum of the energy cost of the blood in a vessel and the energy cost of pumping blood through the vessel. The cost is minimized when vessel radii are consistent with Murray's Law. This law has also been derived from the hypothesis that the shear force of moving blood on the inner walls of vessels is constant throughout the vascular system. However, this derivation, like Murray's earlier derivation, is based on the assumption of constant blood flow. Methods To determine the implications of the constant shear force hypothesis and to extend Murray's energy cost minimization to the pulsatile arterial system, a model of pulsatile flow in an elastic tube is analyzed. A new and exact solution for flow velocity, blood flow rate and shear force is derived. Results For medium and small arteries with pulsatile flow, Murray's energy minimization leads to Murray's Law. Furthermore, the hypothesis that the maximum shear force during the cycle of pulsatile flow is constant throughout the arterial system implies that Murray's Law is approximately true. The approximation is good for all but the largest vessels (aorta and its major branches of the arterial system. Conclusion A cellular mechanism that senses shear force at the inner wall of a blood vessel and triggers remodeling that increases the circumference of the wall when a shear force threshold is exceeded would result in the observed scaling of vessel radii described by Murray's Law.

Legitimacy versus morality: Why do the Chinese obey the law?

Science.gov (United States)

Gao, Jingkang; Zhao, Jinhua

2018-04-01

This study explored two aspects of the rule of law in China: (1) motivations for compliance with 4 groups of everyday laws and regulations and (2) determinants of the legitimacy of legal authorities. We applied a structural equations model, constructed from Tyler's conceptual process-based self-regulation model with morality added as a motivation, to online questionnaire responses from 1,000 Shanghai drivers. We explored the compliance with four particular groups of laws: public disturbance; conventional traffic laws; illegal downloading; and distracted driving. The results were threefold. First, for all four groups of laws, the perceived morality influenced compliance consistently and more strongly than the perceived legitimacy of the authorities and all other motivations. The influence of perceived legitimacy of authorities was inconsistent across the four groups of laws tested. Second, the influence of perceived severity of punishment was consistent and significant across all four groups of laws, whereas perceived risk of apprehension had no significant impact on compliance. Third, evaluations of procedural fairness, not those concerning the equitable distribution of law enforcement services and effectiveness of law enforcement, were most strongly linked to legitimacy. In addition to showing that China is a law-abiding society governed by morality, these results underscore the importance of examining morality and magnitude of punishment as potential motivations for compliance in addition to legitimacy and certainty of punishment. They also illustrate the necessity to examine different groups of laws separately when studying compliance. Finally, these results challenge the linkage between legitimacy and compliance previously established in the literature. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The Aplication of Islamic Law in Indonesia: the Case Study in Aceh

OpenAIRE

Bustamam-Ahmad, Kamaruzzaman

2007-01-01

This article provides an historical account of the implementation of Islamic law in Aceh and how the issue of Islamic law has been debated. The study will give more emphasis on the dynamics of the implementation of Islamic law, its historical development, typologies of Islamic law, leaders’ opinions regarding this issue, and the governments’ responses. This study argues that Islamic law in Aceh has been misinterpreted merely as h{udu>d law. In addition, it argues that the provincial govern...

Estimation of settling velocity of sediment particles in estuarine and coastal waters

Science.gov (United States)

Nasiha, Hussain J.; Shanmugam, Palanisamy

2018-04-01

A model for estimating the settling velocity of sediment particles (spherical and non-spherical) in estuarine and coastal waters is developed and validated using experimental data. The model combines the physical, optical and hydrodynamic properties of the particles and medium to estimate the sediment settling velocity. The well-known Stokes law is broadened to account for the influencing factors of settling velocity such as particle size, shape and density. To derive the model parameters, laboratory experiments were conducted using natural flaky seashells, spherical beach sands and ball-milled seashell powders. Spectral light backscattering measurements of settling particles in a water tank were made showing a distinct optical feature with a peak shifting from 470-490 nm to 500-520 nm for particle populations from spherical to flaky grains. This significant optical feature was used as a proxy to make a shape determination in the present model. Other parameters experimentally determined included specific gravity (ΔSG) , Corey shape factor (CSF) , median grain diameter (D50) , drag coefficient (Cd) and Reynolds number (Re) . The CSF values considered ranged from 0.2 for flaky to 1.0 for perfectly spherical grains and Reynolds numbers from 2.0 to 105 for the laminar to turbulent flow regimes. The specific gravity of submerged particles was optically derived and used along with these parameters to estimate the sediment settling velocity. Comparison with the experiment data showed that the present model estimated settling velocities of spherical and non-spherical particles that were closely consistent with the measured values. Findings revealed that for a given D50, the flaky particles caused a greater decrease in settling velocity than the spherical particles which suggests that the particle shape factor has a profound role in influencing the sediment settling velocity and drag coefficients, especially in transitional and turbulent flow regimes. The present model can

Regulating Listed Companies: Between Company Law and Financial Market Law in Danish Law

DEFF Research Database (Denmark)

Clausen, Nis Jul

2011-01-01

The article discusses different elements and aspects of the regulation of listed companies in particular whether such regulation should be placed in company law or in financial marked law.......The article discusses different elements and aspects of the regulation of listed companies in particular whether such regulation should be placed in company law or in financial marked law....

Referencing geostrophic velocities using ADCP data Referencing geostrophic velocities using ADCP data

Directory of Open Access Journals (Sweden)

Isis Comas-Rodríguez

2010-06-01

Full Text Available Acoustic Doppler Current Profilers (ADCPs have proven to be a useful oceanographic tool in the study of ocean dynamics. Data from D279, a transatlantic hydrographic cruise carried out in spring 2004 along 24.5°N, were processed, and lowered ADCP (LADCP bottom track data were used to assess the choice of reference velocity for geostrophic calculations. The reference velocities from different combinations of ADCP data were compared to one another and a reference velocity was chosen based on the LADCP data. The barotropic tidal component was subtracted to provide a final reference velocity estimated by LADCP data. The results of the velocity fields are also shown. Further studies involving inverse solutions will include the reference velocity calculated here.

Free-surface velocity measurements using an optically recording velocity interferometer

International Nuclear Information System (INIS)

Lu Jianxin; Wang Zhao; Liang Jing; Shan Yusheng; Zhou Chuangzhi; Xiang Yihuai; Lu Ze; Tang Xiuzhang

2006-01-01

An optically recording velocity interferometer system (ORVIS) was developed for the free-surface velocity measurements in the equation of state experiments. The time history of free-surface velocity could be recorded by the electronic streak camera. In the experiments, ORVIS got a 179 ps time resolution, and a higher time resolution could be got by minimizing the delay time. The equation of state experiments were carried out on the high power excimer laser system called 'Heaven I' with laser wavelength of 248.4 nm, pulse duration of 25 ns and maximum energy 158 J. Free-surface velocity of 20 μm thick iron got 3.86 km/s with laser intensity of 6.24 x 10 11 W·cm -2 , and free-surface velocity of 100 μm thick aluminum with 100 μm CH foil at the front got 2.87 km/s with laser intensity 7.28 x 10 11 W·cm -2 . (authors)

Optical-fiber interferometer for velocity measurements with picosecond resolution

International Nuclear Information System (INIS)

Weng Jidong; Tan Hua; Wang Xiang; Ma Yun; Hu Shaolou; Wang Xiaosong

2006-01-01

The conventional Doppler laser-interference velocimeters are made up of traditional optical elements such as lenses and mirrors and will generally restrict its applications in multipoint velocity measurements. By transfering the light from multimode optical fiber to single-mode optical fiber and using the currently available conventional telecommunications elements, the authors have constructed a velocimeter called all-fiber displacement interferometer system for any reflector. The unique interferometer system is only made up of fibers or fiber-coupled components. The viability of this technique is demonstrated by measuring the velocity of an interface moving at velocity of 2133 m/s with 50 ps time resolution. In addition, the concept of optical-fiber mode conversion would provide a way to develop various optical-fiber sensors

Velocity control in Parkinson's disease: a quantitative analysis of isochrony in scribbling movements.

Science.gov (United States)

Viviani, Paolo; Burkhard, Pierre R; Chiuvé, Sabina Catalano; Corradi-Dell'Acqua, Corrado; Vindras, Philippe

2009-04-01

An experiment was conducted to contrast the motor performance of three groups (N = 20) of participants: (1) patients with confirmed Parkinson Disease (PD) diagnose; (2) age-matched controls; (3) young adults. The task consisted of scribbling freely for 10 s within circular frames of different sizes. Comparison among groups focused on the relation between the figural elements of the trace (overall size and trace length) and the velocity of the drawing movements. Results were analysed within the framework of previous work on normal individuals showing that instantaneous velocity of drawing movements depends jointly on trace curvature (Two-thirds Power Law) and trace extent (Isochrony principle). The motor behaviour of PD patients exhibited all classical symptoms of the disease (reduced average velocity, reduced fluency, micrographia). At a coarse level of analysis both isochrony and the dependence of velocity on curvature, which are supposed to reflect cortical mechanisms, were spared in PD patients. Instead, significant differences with respects to the control groups emerged from an in-depth analysis of the velocity control suggesting that patients did not scale average velocity as effectively as controls. We factored out velocity control by distinguishing the influence of the broad context in which movement is planned--i.e. the size of the limiting frames--from the influence of the local context--i.e. the linear extent of the unit of motor action being executed. The balance between the two factors was found to be distinctively different in PD patients and controls. This difference is discussed in the light of current theorizing on the role of cortical and sub-cortical mechanisms in the aetiology of PD. We argue that the results are congruent with the notion that cortical mechanisms are responsible for generating a parametric template of the desired movement and the BG specify the actual spatio-temporal parameters through a multiplicative gain factor acting on both

Measuring the Alfvénic nature of the interstellar medium: Velocity anisotropy revisited

International Nuclear Information System (INIS)

Burkhart, Blakesley; Lazarian, A.; Leão, I. C.; De Medeiros, J. R.; Esquivel, A.

2014-01-01

The dynamics of the interstellar medium (ISM) are strongly affected by turbulence, which shows increased anisotropy in the presence of a magnetic field. We expand upon the Esquivel and Lazarian method to estimate the Alfvén Mach number using the structure function anisotropy in velocity centroid data from Position-Position-Velocity maps. We utilize three-dimensional magnetohydrodynamic simulations of fully developed turbulence, with a large range of sonic and Alfvénic Mach numbers, to produce synthetic observations of velocity centroids with observational characteristics such as thermal broadening, cloud boundaries, noise, and radiative transfer effects of carbon monoxide. In addition, we investigate how the resulting anisotropy-Alfvén Mach number dependency found in Esquivel and Lazarian might change when taking the second moment of the Position-Position-Velocity cube or when using different expressions to calculate the velocity centroids. We find that the degree of anisotropy is related primarily to the magnetic field strength (i.e., Alfvén Mach number) and the line-of-sight orientation, with a secondary effect on sonic Mach number. If the line of sight is parallel to up to ≈45 deg off of the mean field direction, the velocity centroid anisotropy is not prominent enough to distinguish different Alfvénic regimes. The observed anisotropy is not strongly affected by including radiative transfer, although future studies should include additional tests for opacity effects. These results open up the possibility of studying the magnetic nature of the ISM using statistical methods in addition to existing observational techniques.

Entropy Generation Analysis of Power-Law Non-Newtonian Fluid Flow Caused by Micropatterned Moving Surface

Directory of Open Access Journals (Sweden)

M. H. Yazdi

2014-01-01

Full Text Available In the present study, the first and second law analyses of power-law non-Newtonian flow over embedded open parallel microchannels within micropatterned permeable continuous moving surface are examined at prescribed surface temperature. A similarity transformation is used to reduce the governing equations to a set of nonlinear ordinary differential equations. The dimensionless entropy generation number is formulated by an integral of the local rate of entropy generation along the width of the surface based on an equal number of microchannels and no-slip gaps interspersed between those microchannels. The velocity, the temperature, the velocity gradient, and the temperature gradient adjacent to the wall are substituted into this equation resulting from the momentum and energy equations obtained numerically by Dormand-Prince pair and shooting method. Finally, the entropy generation numbers, as well as the Bejan number, are evaluated. It is noted that the presence of the shear thinning (pseudoplastic fluids creates entropy along the surface, with an opposite effect resulting from shear thickening (dilatant fluids.

On linear relationship between shock velocity and particle velocity

International Nuclear Information System (INIS)

Dandache, H.

1986-11-01

We attempt to derive the linear relationship between shock velocity U s and particle velocity U p from thermodynamic considerations, taking into account an ideal gas equation of state and a Mie-Grueneisen equation of state for solids. 23 refs

THE RADIAL VELOCITY EXPERIMENT (RAVE): THIRD DATA RELEASE

International Nuclear Information System (INIS)

Siebert, A.; Williams, M. E. K.; Siviero, A.; Boeche, C.; Steinmetz, M.; De Jong, R. S.; Enke, H.; Anguiano, B.; Reid, W.; Ritter, A.; Fulbright, J.; Wyse, R. F. G.; Munari, U.; Zwitter, T.; Watson, F. G.; Burton, D.; Cass, C. J. P.; Fiegert, K.; Hartley, M.; Russel, K. S.

2011-01-01

We present the third data release of the RAdial Velocity Experiment (RAVE) which is the first milestone of the RAVE project, releasing the full pilot survey. The catalog contains 83,072 radial velocity measurements for 77,461 stars in the southern celestial hemisphere, as well as stellar parameters for 39,833 stars. This paper describes the content of the new release, the new processing pipeline, as well as an updated calibration for the metallicity based upon the observation of additional standard stars. Spectra will be made available in a future release. The data release can be accessed via the RAVE Web site.

Effects of errors in velocity tilt on maximum longitudinal compression during neutralized drift compression of intense beam pulses: I. general description

Energy Technology Data Exchange (ETDEWEB)

Kaganovich, Igor D.; Massidda, Scottt; Startsev, Edward A.; Davidson, Ronald C.; Vay, Jean-Luc; Friedman, Alex

2012-06-21

Neutralized drift compression offers an effective means for particle beam pulse compression and current amplification. In neutralized drift compression, a linear longitudinal velocity tilt (head-to-tail gradient) is applied to the non-relativistic beam pulse, so that the beam pulse compresses as it drifts in the focusing section. The beam current can increase by more than a factor of 100 in the longitudinal direction. We have performed an analytical study of how errors in the velocity tilt acquired by the beam in the induction bunching module limit the maximum longitudinal compression. It is found that the compression ratio is determined by the relative errors in the velocity tilt. That is, one-percent errors may limit the compression to a factor of one hundred. However, a part of the beam pulse where the errors are small may compress to much higher values, which are determined by the initial thermal spread of the beam pulse. It is also shown that sharp jumps in the compressed current density profile can be produced due to overlaying of different parts of the pulse near the focal plane. Examples of slowly varying and rapidly varying errors compared to the beam pulse duration are studied. For beam velocity errors given by a cubic function, the compression ratio can be described analytically. In this limit, a significant portion of the beam pulse is located in the broad wings of the pulse and is poorly compressed. The central part of the compressed pulse is determined by the thermal spread. The scaling law for maximum compression ratio is derived. In addition to a smooth variation in the velocity tilt, fast-changing errors during the pulse may appear in the induction bunching module if the voltage pulse is formed by several pulsed elements. Different parts of the pulse compress nearly simultaneously at the target and the compressed profile may have many peaks. The maximum compression is a function of both thermal spread and the velocity errors. The effects of the

A new guidance law for a tactical surface-to-surface missile

Directory of Open Access Journals (Sweden)

Danilo V. Ćuk

2012-01-01

Full Text Available Modern tactical surface-to-surface missiles, equipped with strapdown inertial navigation systems, achieve very good accuracy compared with free-flight rockets. The probable range dispersion mainly depends on instruments errors and longitudinal disturbances such as rocket motor total-impulse deviation as well as differences between the estimated and actual values of the axial force and head wind. This paper gives an extension of the correlated velocity concept for surface-to-surface missiles without a thrust-terminating mechanism. The calculated parameters of the correlated velocity are stored into the memory of an onboard guidance computer. On the basis of the correlated velocity concept, the modified proportional navigation with the adjustment of the time-to-go of the missile to the target was proposed. It is shown that the new guidance law can compensate for the longitudinal disturbances of different levels successfully. The effectiveness of the proposed guidance method was confirmed by means of the calculated probable range and lateral dispersion for the anticipated disturbances in the guidance system.

On Newton's third law and its symmetry-breaking effects

International Nuclear Information System (INIS)

Pinheiro, Mario J

2011-01-01

The law of action-reaction, considered by Ernst Mach as the cornerstone of physics, is thoroughly used to derive the conservation laws of linear and angular momentum. However, the conflict between momentum conservation law and Newton's third law, on experimental and theoretical grounds, calls for more attention. We give a background survey of several questions raised by the action-reaction law and, in particular, the role of the physical vacuum is shown to provide an appropriate framework for clarifying the occurrence of possible violations of the action-reaction law. Then, in the framework of statistical mechanics, using a maximizing entropy procedure, we obtain an expression for the general linear momentum of a body particle. The new approach presented here shows that Newton's third law is not verified in systems out of equilibrium due to an additional entropic gradient term present in the particle's momentum.

Fighting by the principles: principles as a source of international humanitarian law

NARCIS (Netherlands)

van den Boogaard, J.C.; Matthee, M.; Toebes, B.; Brus, M.

2013-01-01

The rules of international humanitarian law of armed conflict are codified in a rather extensive body of treaty law. In addition, extensive research has been conducted into the rules of customary international humanitarian law. The author of this contribution will argue that there is another

Development of vortex model with realistic axial velocity distribution

International Nuclear Information System (INIS)

Ito, Kei; Ezure, Toshiki; Ohshima, Hiroyuki

2014-01-01

A vortex is considered as one of significant phenomena which may cause gas entrainment (GE) and/or vortex cavitation in sodium-cooled fast reactors. In our past studies, the vortex is assumed to be approximated by the well-known Burgers vortex model. However, the Burgers vortex model has a simple but unreal assumption that the axial velocity component is horizontally constant, while in real the free surface vortex has the axial velocity distribution which shows large gradient in radial direction near the vortex center. In this study, a new vortex model with realistic axial velocity distribution is proposed. This model is derived from the steady axisymmetric Navier-Stokes equation as well as the Burgers vortex model, but the realistic axial velocity distribution in radial direction is considered, which is defined to be zero at the vortex center and to approach asymptotically to zero at infinity. As the verification, the new vortex model is applied to the evaluation of a simple vortex experiment, and shows good agreements with the experimental data in terms of the circumferential velocity distribution and the free surface shape. In addition, it is confirmed that the Burgers vortex model fails to calculate accurate velocity distribution with the assumption of uniform axial velocity. However, the calculation accuracy of the Burgers vortex model can be enhanced close to that of the new vortex model in consideration of the effective axial velocity which is calculated as the average value only in the vicinity of the vortex center. (author)

Determination of the filtration velocities and mean velocity in ground waters using radiotracers

International Nuclear Information System (INIS)

Duran P, Oscar; Diaz V, Francisco; Heresi M, Nelida

1994-01-01

An experimental method to determine filtration, or, Darcy velocity and mean velocity in underground waters using radiotracers, is described. After selecting the most appropriate tracers, from 6 chemical compounds, to measure water velocity, a method to measure filtration velocity was developed. By fully labelling the water column with 2 radioisotopes, Br and tritium, almost identical values were obtained for the aquifer filtration velocity in the sounding S1. This value was 0.04 m/d. Field porosity was calculated at 11% and mean velocity at 0.37 m.d. With the filtration velocity value and knowing the hydraulic variation between the soundings S1 and S2 placed at 10 meters, field permeability was estimated at 2.4 x 10 m/s. (author)

THE STAR FORMATION LAWS OF EDDINGTON-LIMITED STAR-FORMING DISKS

International Nuclear Information System (INIS)

Ballantyne, D. R.; Armour, J. N.; Indergaard, J.

2013-01-01

Two important avenues into understanding the formation and evolution of galaxies are the Kennicutt-Schmidt (K-S) and Elmegreen-Silk (E-S) laws. These relations connect the surface densities of gas and star formation (Σ gas and Σ-dot * , respectively) in a galaxy. To elucidate the K-S and E-S laws for disks where Σ gas ∼> 10 4 M ☉ pc –2 , we compute 132 Eddington-limited star-forming disk models with radii spanning tens to hundreds of parsecs. The theoretically expected slopes (≈1 for the K-S law and ≈0.5 for the E-S relation) are relatively robust to spatial averaging over the disks. However, the star formation laws exhibit a strong dependence on opacity that separates the models by the dust-to-gas ratio that may lead to the appearance of a erroneously large slope. The total infrared luminosity (L TIR ) and multiple carbon monoxide (CO) line intensities were computed for each model. While L TIR can yield an estimate of the average Σ-dot * that is correct to within a factor of two, the velocity-integrated CO line intensity is a poor proxy for the average Σ gas for these warm and dense disks, making the CO conversion factor (α CO ) all but useless. Thus, observationally derived K-S and E-S laws at these values of Σ gas that uses any transition of CO will provide a poor measurement of the underlying star formation relation. Studies of the star formation laws of Eddington-limited disks will require a high-J transition of a high density molecular tracer, as well as a sample of galaxies with known metallicity estimates.

Remote measurement of surface-water velocity using infrared videography and PIV: a proof-of-concept for Alaskan rivers

Science.gov (United States)

Kinzel, Paul J.; Legleiter, Carl; Nelson, Jonathan M.; Conaway, Jeffrey S.

2017-01-01

Thermal cameras with high sensitivity to medium and long wavelengths can resolve features at the surface of flowing water arising from turbulent mixing. Images acquired by these cameras can be processed with particle image velocimetry (PIV) to compute surface velocities based on the displacement of thermal features as they advect with the flow. We conducted a series of field measurements to test this methodology for remote sensing of surface velocities in rivers. We positioned an infrared video camera at multiple stations across bridges that spanned five rivers in Alaska. Simultaneous non-contact measurements of surface velocity were collected with a radar gun. In situ velocity profiles were collected with Acoustic Doppler Current Profilers (ADCP). Infrared image time series were collected at a frequency of 10Hz for a one-minute duration at a number of stations spaced across each bridge. Commercial PIV software used a cross-correlation algorithm to calculate pixel displacements between successive frames, which were then scaled to produce surface velocities. A blanking distance below the ADCP prevents a direct measurement of the surface velocity. However, we estimated surface velocity from the ADCP measurements using a program that normalizes each ADCP transect and combines those normalized transects to compute a mean measurement profile. The program can fit a power law to the profile and in so doing provides a velocity index, the ratio between the depth-averaged and surface velocity. For the rivers in this study, the velocity index ranged from 0.82 – 0.92. Average radar and extrapolated ADCP surface velocities were in good agreement with average infrared PIV calculations.

Criminal Law

DEFF Research Database (Denmark)

Langsted, Lars Bo; Garde, Peter; Greve, Vagn

<> book contains a thorough description of Danish substantive criminal law, criminal procedure and execution of sanctions. The book was originally published as a monograph in the International Encyclopaedia of Laws/Criminal Law....... book contains a thorough description of Danish substantive criminal law, criminal procedure and execution of sanctions. The book was originally published as a monograph in the International Encyclopaedia of Laws/Criminal Law....

Two-velocity elasticity theory and facet growth

OpenAIRE

Andreev, A. F.; Melnikovsky, L. A.

2002-01-01

We explain the linear growth of smooth solid helium facets by the presence of lattice point defects. To implement this task, the framework of very general two-velocity elasticity theory equations is developed. Boundary conditions for these equations for various surface types are derived. We also suggest additional experiments to justify the concept.

Radial velocity asymmetries from jets with variable velocity profiles

International Nuclear Information System (INIS)

Cerqueira, A. H.; Vasconcelos, M. J.; Velazquez, P. F.; Raga, A. C.; De Colle, F.

2006-01-01

We have computed a set of 3-D numerical simulations of radiatively cooling jets including variabilities in both the ejection direction (precession) and the jet velocity (intermittence), using the Yguazu-a code. In order to investigate the effects of jet rotation on the shape of the line profiles, we also introduce an initial toroidal rotation velocity profile. Since the Yguazu-a code includes an atomic/ionic network, we are able to compute the emission coefficients for several emission lines, and we generate line profiles for the Hα, [O I]λ6300, [S II]λ6716 and [N II]λ6548 lines. Using initial parameters that are suitable for the DG Tau microjet, we show that the computed radial velocity shift for the medium-velocity component of the line profile as a function of distance from the jet axis is strikingly similar for rotating and non-rotating jet models

A Velocity-Aware Handover Trigger in Two-Tier Heterogeneous Networks

Directory of Open Access Journals (Sweden)

Asmae Ait Mansour

2018-01-01

Full Text Available The unexpected change in user equipment (UE velocity is recognized as the primary explanation for poor handover quality. In order to resolve this issue, while limiting ping-pong (PP events we carefully and dynamically optimized handover parameters for each UE unit according to its velocity and the coverage area of the access point (AP. In order to recognize any variations in velocity, we applied Allan variance (AVAR to the received signal strength (RSS from the serving AP. To assess our approach, it was essential to configure a heterogeneous network context (LTE-WiFi and interconnect Media-Independent Handover (MIH and Proxy Mobile IPv6 (PMIPv6 for seamless handover. Reproduction demonstrated that our approach does not only result in a gain in relatively accurate velocity but in addition reduces the number of PP and handover failures (HOFs.

Welding wire velocity modelling and control using an optical sensor

DEFF Research Database (Denmark)

Nielsen, Kirsten M.; Pedersen, Tom S.

2007-01-01

In this paper a method for controlling the velocity of a welding wire at the tip of the handle is described. The method is an alternative to the traditional welding apparatus control system where the wire velocity is controlled internal in the welding machine implying a poor disturbance reduction....... To obtain the tip velocity a dynamic model of the wire/liner system is developed and verified.  In the wire/liner system it turned out that backlash and reflections are influential factors. An idea for handling the backlash has been suggested. In addition an optical sensor for measuring the wire velocity...... at the tip has been constructed. The optical sensor may be used but some problems due to focusing cause noise in the control loop demanding a more precise mechanical wire feed system or an optical sensor with better focusing characteristics....

Why atomic energy affects Civil Law

International Nuclear Information System (INIS)

Knieper, R.

1980-01-01

Based on the decision of July 20, 1979 by the Amtsgericht Stuttgart, which dismissed the complaint filed by the Technische Werke der Stadt Stuttgart (public utility) against electricity boycotters as being unfounded for the time being, the author states that a political function is due to Civil Law. The concrete question is whether political considerations have surpassed the limits of laws and interpretations bound by the basic rights. The relationship between a customer depending on power supply and the supply monopolist exceeds contractual relationship by far since it is a social relationship: it is inescapably embraced by the customer's dependence on power supply and by the customer being subject to research work. Atomic energy is being introduced into law of contract by means of dogmatic crutches - breach of additional obligation under a contract. However, in Civil Law, there are a great number of such means enabling solutions to be corrected which seem to be inadequate. (HSCH) [de

A comparative policy analysis of seat belt laws : final report.

Science.gov (United States)

2014-06-24

This analysis examined data from a variety of sources to estimate the benefit of enhancing Iowas current law to require all : passengers to use seat belts. In addition to assessing Iowans opinions about changing the law, a literature review, a ...

Threshold law for positron-atom impact ionisation

International Nuclear Information System (INIS)

Temkin, A.

1982-01-01

The threshold law for ionisation of atoms by positron impact is adduced in analogy with the author's approach to the electron-atom ionisation. It is concluded the Coulomb-dipole region of potential gives the essential part of the interaction in both cases and leads to the same kind of result: a modulated linear law. An additional process which enters positron ionisation is positronium formation in the continuum, but that will not dominate the threshold yield. The result is in sharp contrast to the positron threshold law as recently derived by Klar (J. Phys. B.; 14:4165 (1981)) on the basis of a Wannier-type (Phys. Rev.; 90:817 (1953)) analysis. (author)

On the obligation to obey the law

Directory of Open Access Journals (Sweden)

Zekavica Radomir G.

2016-01-01

Full Text Available The paper considers the question of a general obligation to obey the law. The author presents and analyzes the most significant views and arguments in support of the thesis that there is a general obligation to obey the law, as well as those understandings which are refuse this thesis. In concluding remarks the author presents a critical review of some key issues about general obligation to obey the law. In addition, the author outlines a hypothetical model of society and the legal system under which such an obligation is possible and has also asserted the basic assumptions and principles upon which it can be justified and reasonable. .

Civil law

NARCIS (Netherlands)

Hesselink, M.W.; Gibbons, M.T.

2014-01-01

The concept of civil law has two distinct meanings. that is, disputes between private parties (individuals, corporations), as opposed to other branches of the law, such as administrative law or criminal law, which relate to disputes between individuals and the state. Second, the term civil law is

World law

Directory of Open Access Journals (Sweden)

Harold J. Berman

1999-03-01

Full Text Available In the third millennium of the Christian era, which is characterised by the emergence of a world economy and eventually a world society, the concept of world law is needed to embrace not only the traditional disciplines of public international law, and comparative law, but also the common underlying legal principles applicable in world trade, world finance, transnational transfer of technology and other fields of world economic law, as well as in such emerging fields as the protection of the world's environment and the protection of universal human rights. World law combines inter-state law with the common law of humanity and the customary law of various world communities.

Time dependent response of low velocity impact induced composite conical shells under multiple delamination

Science.gov (United States)

Dey, Sudip; Karmakar, Amit

2014-02-01

This paper presents the time dependent response of multiple delaminated angle-ply composite pretwisted conical shells subjected to low velocity normal impact. The finite element formulation is based on Mindlin's theory incorporating rotary inertia and effects of transverse shear deformation. An eight-noded isoparametric plate bending element is employed to satisfy the compatibility of deformation and equilibrium of resultant forces and moments at the delamination crack front. A multipoint constraint algorithm is incorporated which leads to asymmetric stiffness matrices. The modified Hertzian contact law which accounts for permanent indentation is utilized to compute the contact force, and the time dependent equations are solved by Newmark's time integration algorithm. Parametric studies are conducted with respect to triggering parameters like laminate configuration, location of delamination, angle of twist, velocity of impactor, and impactor's displacement for centrally impacted shells.

Internationalization of law globalization, international law and complexity

CERN Document Server

Dias Varella, Marcelo

2014-01-01

The book provides an overview of how international law is today constructed through diverse macro and microprocesses that expand its traditional subjects and sources, with the attribution of sovereign capacity and power to the international plane (moving the international toward the national). Simultaneously, national laws approximate laws of other nations (moving among nations or moving the national toward the international) and new sources of legal norms emerge, independent of states and international organisations. This expansion occurs in many subject areas, with specific structures: commercial, environmental, human rights, humanitarian, financial, criminal and labor law contribute to the formation of post national law with different modes of functioning, different actors and different sources of law that should be understood as a new complexity of law.

On heat transfer of weakly compressible power-law flows

Directory of Open Access Journals (Sweden)

Li Botong

2017-01-01

Full Text Available This paper completes a numerical research on steady momentum and heat transfer in power-law fluids in a channel. Weakly compressible laminar fluids are studied with no slip at the walls and uniform wall temperatures. The full governing equations are solved by continuous finite element method. Three thermal conductivity models are adopted in this paper, that is, constant thermal conductivity model, thermal conductivity varying as a function of temperature gradient, and a modified temperature-gradient-dependent thermal conductivity model. The results are compared with each other and the physical characteristics for values of parameters are also discussed in details. It is shown that the velocity curve from the solution becomes straight at higher power-law index. The effects of Reynolds numbers on the dilatant fluid and the pseudo-plastic look similar to each other and their trends can be easily predicted. Furthermore, for different models, the temperature curves also present pseudo-plastic and dilatant properties.

Kinematic feedback control laws for generating natural arm movements

International Nuclear Information System (INIS)

Kim, Donghyun; Jang, Cheongjae; Park, Frank C

2014-01-01

We propose a stochastic optimal feedback control law for generating natural robot arm motions. Our approach, inspired by the minimum variance principle of Harris and Wolpert (1998 Nature 394 780–4) and the optimal feedback control principles put forth by Todorov and Jordan (2002 Nature Neurosci. 5 1226–35) for explaining human movements, differs in two crucial respects: (i) the endpoint variance is minimized in joint space rather than Cartesian hand space, and (ii) we ignore the dynamics and instead consider only the second-order differential kinematics. The feedback control law generating the motions can be straightforwardly obtained by backward integration of a set of ordinary differential equations; these equations are obtained exactly, without any linear–quadratic approximations. The only parameters to be determined a priori are the variance scale factors, and for both the two-DOF planar arm and the seven-DOF spatial arm, a table of values is constructed based on the given initial and final arm configurations; these values are determined via an optimal fitting procedure, and consistent with existing findings about neuromuscular motor noise levels of human arm muscles. Experiments conducted with a two-link planar arm and a seven-DOF spatial arm verify that the trajectories generated by our feedback control law closely resemble human arm motions, in the sense of producing nearly straight-line hand trajectories, having bell-shaped velocity profiles, and satisfying Fitts Law. (paper)

Considerations on post-production obligations in terms of Atomic Energy Law

International Nuclear Information System (INIS)

Rebentisch, M.

1992-01-01

The article describes and evaluates the laws concerning the decommissioning and dismantling of nuclear power plants and offers suggestions for possible new regulations. The contribution examines fundamental legal aspects, the instrumentalization of post-production obligations in terms of atomic energy laws, especially the question as to how to bring the Atomic Energy Law into accord with the Federal Emission Control Law within the realm of decommissioning laws, licences for safe confinement and dismantling of a plant, and in addition questions on making financial provisions for decommissioning. (orig./HSCH) [de

Evaluation of Maryland abutment scour equation through selected threshold velocity methods

Science.gov (United States)

Benedict, S.T.

2010-01-01

The U.S. Geological Survey, in cooperation with the Maryland State Highway Administration, used field measurements of scour to evaluate the sensitivity of the Maryland abutment scour equation to the critical (or threshold) velocity variable. Four selected methods for estimating threshold velocity were applied to the Maryland abutment scour equation, and the predicted scour to the field measurements were compared. Results indicated that performance of the Maryland abutment scour equation was sensitive to the threshold velocity with some threshold velocity methods producing better estimates of predicted scour than did others. In addition, results indicated that regional stream characteristics can affect the performance of the Maryland abutment scour equation with moderate-gradient streams performing differently from low-gradient streams. On the basis of the findings of the investigation, guidance for selecting threshold velocity methods for application to the Maryland abutment scour equation are provided, and limitations are noted.

Environmental law and nuclear law: a growing symbiosis

International Nuclear Information System (INIS)

Ennerechts, S.

2008-01-01

This article is divided in two parts. The first part deals with the interrelationship between environmental law and nuclear law. It specifically addresses selective topics which the author considers as substantial proof that environmental law is in evidence in the nuclear field. These topics are access to nuclear information, public participation in nuclear decision-making and prevention and compensation of environmental damage caused by nuclear incidents. Environmental law will be considered in its narrow sense, meaning the law that seeks to protect nature such as soil, water, air and biodiversity. The position of the author is that the importance of environmental law for nuclear activities is increasing and may lead to a growing symbiosis with nuclear law. Environmental law and nuclear law share the same objectives: protection against mitigation of and compensation for damage to the environment. In the second part a specific problem that touches upon the extra-territorial effect of environmental legislation in the nuclear field will be examined. At the beginning of the 21. century, it can be expected that vendors of nuclear facilities will spare no efforts in trying to enter new markets all over the world. Countries with more developed environmental requirements on the construction of nuclear facilities by their national vendors in customer countries. This part of the article will analyse whether public international laws to the construction of nuclear facilities abroad. The author believes that there may well be a legal basis under customary international law justifying the application of national environmental law to the construction of nuclear facilities and the performance of work on nuclear facilities in foreign countries, but there would appear to be none permitting the enforcement of these laws in the absence of an agreement with the foreign country. (N.C.)

Determination of the effect of wind velocity and direction changes on turbidity removal in rectangular sedimentation tanks.

Science.gov (United States)

Khezri, Seyed Mostafa; Biati, Aida; Erfani, Zeynab

2012-01-01

In the present study, a pilot-scale sedimentation tank was used to determine the effect of wind velocity and direction on the removal efficiency of particles. For this purpose, a 1:20 scale pilot simulated according to Frude law. First, the actual efficiency of total suspended solids (TSS) removal was calculated in no wind condition. Then, the wind was blown in the same and the opposite directions of water flow. At each direction TSS removal was calculated at three different velocities from 2.5 to 7 m/s. Results showed that when the wind was in the opposite direction of water flow, TSS removal efficiency initially increased with the increase of wind velocity from 0 to 2.5 m/s, then it decreased with the increase of velocity to 5 m/s. This mainly might happen because the opposite direction of wind can increase particles' retention time in the sedimentation tank. However, higher wind velocities (i.e. 3.5 and 5.5 m/s) could not increase TSS removal efficiency. Thus, if sedimentation tanks are appropriately exposed to the wind, TSS removal efficiency increases by approximately 6%. Therefore, energy consumption will be reduced by a proper site selection for sedimentation tank unit in water and waste water treatment plants.

Propagation of the Semidiurnal Internal Tide: Phase Velocity Versus Group Velocity

Science.gov (United States)

Zhao, Zhongxiang

2017-12-01

The superposition of two waves of slightly different wavelengths has long been used to illustrate the distinction between phase velocity and group velocity. The first-mode M2 and S2 internal tides exemplify such a two-wave model in the natural ocean. The M2 and S2 tidal frequencies are 1.932 and 2 cycles per day, respectively, and their superposition forms a spring-neap cycle in the semidiurnal band. The spring-neap cycle acts like a wave, with its frequency, wave number, and phase being the differences of the M2 and S2 internal tides. The spring-neap cycle and energy of the semidiurnal internal tide propagate at the group velocity. Long-range propagation of M2 and S2 internal tides in the North Pacific is observed by satellite altimetry. Along a 3,400 km beam spanning 24°-54°N, the M2 and S2 travel times are 10.9 and 11.2 days, respectively. For comparison, it takes the spring-neap cycle 21.1 days to travel over this distance. Spatial maps of the M2 phase velocity, the S2 phase velocity, and the group velocity are determined from phase gradients of the corresponding satellite observed internal tide fields. The observed phase and group velocities agree with theoretical values estimated using the World Ocean Atlas 2013 annual-mean ocean stratification.

Centrifugal fans: Similarity, scaling laws, and fan performance

Science.gov (United States)

Sardar, Asad Mohammad

Centrifugal fans are rotodynamic machines used for moving air continuously against moderate pressures through ventilation and air conditioning systems. There are five major topics presented in this thesis: (1) analysis of the fan scaling laws and consequences of dynamic similarity on modelling; (2) detailed flow visualization studies (in water) covering the flow path starting at the fan blade exit to the evaporator core of an actual HVAC fan scroll-diffuser module; (3) mean velocity and turbulence intensity measurements (flow field studies) at the inlet and outlet of large scale blower; (4) fan installation effects on overall fan performance and evaluation of fan testing methods; (5) two point coherence and spectral measurements conducted on an actual HVAC fan module for flow structure identification of possible aeroacoustic noise sources. A major objective of the study was to identity flow structures within the HVAC module that are responsible for noise and in particular "rumble noise" generation. Possible mechanisms for the generation of flow induced noise in the automotive HVAC fan module are also investigated. It is demonstrated that different modes of HVAC operation represent very different internal flow characteristics. This has implications on both fan HVAC airflow performance and noise characteristics. It is demonstrated from principles of complete dynamic similarity that fan scaling laws require that Reynolds, number matching is a necessary condition for developing scale model fans or fan test facilities. The physical basis for the fan scaling laws derived was established from both pure dimensional analysis and also from the fundamental equations of fluid motion. Fan performance was measured in a three times scale model (large scale blower) in air of an actual forward curved automotive HVAC blower. Different fan testing methods (based on AMCA fan test codes) were compared on the basis of static pressure measurements. Also, the flow through an actual HVAC

Environmental law

International Nuclear Information System (INIS)

Kloepfer, M.

1989-01-01

This comprehensive reference book on environmental law and practice also is a valuable textbook for students specializing in the field. The entire law on pollution control and environmental protection is presented in an intelligent system, covering the latest developments in the Federal and Land legislation, public environmental law, and the related provisions in the fields of civil law and criminal law. The national survey is rounded up by information concerning the international environmental law, environmental law of the European Communities, and of other foreign countries as e.g. Austria and Switzerland. The author also reviews conditions in neighbouring fields such as technology and labour law, environmental economy, environmental policy. Special attention is given to current topics, as e.g. relating to genetic engineering, disused landfills or industrial sites, soil protection, transport of hazardous goods, liability for damage to forests, atomic energy law, and radiation protection law. The latest publishing dates of literature and court decisions considered in the book are in the first months of 1989. (RST) [de

Delayed hydride cracking: theoretical model testing to predict cracking velocity

International Nuclear Information System (INIS)

Mieza, Juan I.; Vigna, Gustavo L.; Domizzi, Gladys

2009-01-01

Pressure tubes from Candu nuclear reactors as any other component manufactured with Zr alloys are prone to delayed hydride cracking. That is why it is important to be able to predict the cracking velocity during the component lifetime from parameters easy to be measured, such as: hydrogen concentration, mechanical and microstructural properties. Two of the theoretical models reported in literature to calculate the DHC velocity were chosen and combined, and using the appropriate variables allowed a comparison with experimental results of samples from Zr-2.5 Nb tubes with different mechanical and structural properties. In addition, velocities measured by other authors in irradiated materials could be reproduced using the model described above. (author)

BRIEF COMMENTS REGARDING THE INDIRECT (OR DERIVED) SOURCES OF LABOR LAW

OpenAIRE

Brîndușa Vartolomei

2015-01-01

In the field of the law governing the legal work relations one of the features that also contributes to defining the autonomy of labor law is that of the existence of the specific sources of law consisting in regulation on the functioning of the employer, internal regulation, collective labor agreement, and instructions regarding the security and labor health. In addition, in the practical field of the labor relationssome indirect (or derived) sources of law were also pointed out ...

VeLoc: Finding Your Car in Indoor Parking Structures.

Science.gov (United States)

Gao, Ruipeng; He, Fangpu; Li, Teng

2018-05-02

While WiFi-based indoor localization is attractive, there are many indoor places without WiFi coverage with a strong demand for localization capability. This paper describes a system and associated algorithms to address the indoor vehicle localization problem without the installation of additional infrastructure. In this paper, we propose VeLoc, which utilizes the sensor data of smartphones in the vehicle together with the floor map of the parking structure to track the vehicle in real time. VeLoc simultaneously harnesses constraints imposed by the map and environment sensing. All these cues are codified into a novel augmented particle filtering framework to estimate the position of the vehicle. Experimental results show that VeLoc performs well when even the initial position and the initial heading direction of the vehicle are completely unknown.

Relation between radius and expansion velocity in planetary nebulae

International Nuclear Information System (INIS)

Chu, Y.H.; Kwitter, K.B.; Kaler, J.B.

1984-01-01

The expansion velocity-radius (R-V) relation for planetary nebulae is examined using the existing measurements of expansion velocities and recent calculations of radii. It is found that some of the previously alleged R-V relations for PN are not convincingly established. The scatter in the R-V plots may be due largely to stratification of ions in individual nebulae and to heterogeneity in the planetary nebula population. In addition, from new echelle/CCD observations of planetary nebulae, it is found that spatial information is essential in deriving the internal kinematic properties. Future investigations of R-V relations should be pursued separately for groups of planetaries with similar physical properties, and they should employ observations of appropriate low excitation lines in order to measure the expansion velocity at the surface of the nebula. 26 references

Determination of velocity correction factors for real-time air velocity monitoring in underground mines.

Science.gov (United States)

Zhou, Lihong; Yuan, Liming; Thomas, Rick; Iannacchione, Anthony

2017-12-01

When there are installations of air velocity sensors in the mining industry for real-time airflow monitoring, a problem exists with how the monitored air velocity at a fixed location corresponds to the average air velocity, which is used to determine the volume flow rate of air in an entry with the cross-sectional area. Correction factors have been practically employed to convert a measured centerline air velocity to the average air velocity. However, studies on the recommended correction factors of the sensor-measured air velocity to the average air velocity at cross sections are still lacking. A comprehensive airflow measurement was made at the Safety Research Coal Mine, Bruceton, PA, using three measuring methods including single-point reading, moving traverse, and fixed-point traverse. The air velocity distribution at each measuring station was analyzed using an air velocity contour map generated with Surfer ® . The correction factors at each measuring station for both the centerline and the sensor location were calculated and are discussed.

Suitability of simple rheological laws for the numerical simulation of dense pyroclastic flows and long-runout volcanic avalanches

Science.gov (United States)

Kelfoun, Karim

2011-08-01

The rheology of volcanic rock avalanches and dense pyroclastic flows is complex, and it is difficult at present to constrain the physics of their processes. The problem lies in defining the most suitable parameters for simulating the behavior of these natural flows. Existing models are often based on the Coulomb rheology, sometimes with a velocity-dependent stress (e.g., Voellmy), but other laws have also been used. Here I explore the characteristics of flows, and their deposits, obtained on simplified topographies by varying source conditions and rheology. The Coulomb rheology, irrespective of whether there is a velocity-dependent stress, forms cone-shaped deposits that do not resemble those of natural long-runout events. A purely viscous or a purely turbulent flow can achieve realistic velocities and thicknesses but cannot form a deposit on slopes. The plastic rheology, with (e.g., Bingham) or without a velocity-dependent stress, is more suitable for the simulation of dense pyroclastic flows and long-runout volcanic avalanches. With this rheology, numerical flows form by pulses, which are often observed during natural flow emplacement. The flows exhibit realistic velocities and deposits of realistic thicknesses. The plastic rheology is also able to generate the frontal lobes and lateral levées which are commonly observed in the field. With the plastic rheology, levée formation occurs at the flow front due to a divergence of the driving stresses at the edges. Once formed, the levées then channel the remaining flow mass. The results should help future modelers of volcanic flows with their choice of which mechanical law corresponds best to the event they are studying.

Case - Case-Law - Law

DEFF Research Database (Denmark)

Sadl, Urska

2013-01-01

Reasoning of the Court of Justice of the European Union – Constr uction of arguments in the case-law of the Court – Citation technique – The use of formulas to transform case-law into ‘law’ – ‘Formulaic style’ – European citizenship as a fundamental status – Ruiz Zambrano – Reasoning from...

Influence of Flow Velocity on Tsunami Loss Estimation

Directory of Open Access Journals (Sweden)

Jie Song

2017-11-01

Full Text Available Inundation depth is commonly used as an intensity measure in tsunami fragility analysis. However, inundation depth cannot be taken as the sole representation of tsunami impact on structures, especially when structural damage is caused by hydrodynamic and debris impact forces that are mainly determined by flow velocity. To reflect the influence of flow velocity in addition to inundation depth in tsunami risk assessment, a tsunami loss estimation method that adopts both inundation depth and flow velocity (i.e., bivariate intensity measures in evaluating tsunami damage is developed. To consider a wide range of possible tsunami inundation scenarios, Monte Carlo-based tsunami simulations are performed using stochastic earthquake slip distributions derived from a spectral synthesis method and probabilistic scaling relationships of earthquake source parameters. By focusing on Sendai (plain coast and Onagawa (ria coast in the Miyagi Prefecture of Japan in a case study, the stochastic tsunami loss is evaluated by total economic loss and its spatial distribution at different scales. The results indicate that tsunami loss prediction is highly sensitive to modelling resolution and inclusion of flow velocity for buildings located less than 1 km from the sea for Sendai and Onagawa of Miyagi Prefecture.

Methodological principles to study formation and development of floristic law in Ukraine

Directory of Open Access Journals (Sweden)

А. К. Соколова

2014-06-01

Full Text Available The paper investigates the problems associated with the determination of methods to study establishment of floristic law in Ukraine. It makes an investigation into the types of methods, establishes their interrelation and functional value. In addition, it analyzes the system of methodological reasons for development of ecological and floristic law and gives additional reasons.

Scaling laws of free dendritic growth in a forced Oseen flow

International Nuclear Information System (INIS)

Kurnatowski, M von; Kassner, K

2014-01-01

We use the method presented in M von Kurnatowski et al (2013 Phys. Rev. E 87 042405) to solve the nonlinear problem of free dendritic growth in an Oseen flow. The growth process is assumed to be limited by thermal transport via diffusion and convection. A singular perturbation expansion is treated to lowest nontrivial order in the framework of asymptotic decomposition. The resulting complex integro-differential equation is solved using an elaborate numerical method. The approximate scaling laws V∝U 2/3 and ρ∝U −1/3 for the growth velocity and the tip radius of curvature of the dendrite, respectively, are found as a function of the forced flow velocity. The results are compared to those by Pelcé and Bouissou, constituting the only other attempt so far to treat the problem analytically. (paper)

Numerical solutions of incompressible Navier-Stokes equations using modified Bernoulli's law

Science.gov (United States)

Shatalov, A.; Hafez, M.

2003-11-01

Simulations of incompressible flows are important for many practical applications in aeronautics and beyond, particularly in the high Reynolds number regime. The present formulation is based on Helmholtz velocity decomposition where the velocity is presented as the gradient of a potential plus a rotational component. Substituting in the continuity equation yields a Poisson equation for the potential which is solved with a zero normal derivative at solid surfaces. The momentum equation is used to update the rotational component with no slip/no penetration surface boundary conditions. The pressure is related to the potential function through a special relation which is a generalization of Bernoulli's law, with a viscous term included. Results of calculations for two- and three-dimensional problems prove that the present formulation is a valid approach, with some possible benefits compared to existing methods.

Uncertainty assessment of 3D instantaneous velocity model from stack velocities

Science.gov (United States)

Emanuele Maesano, Francesco; D'Ambrogi, Chiara

2015-04-01

3D modelling is a powerful tool that is experiencing increasing applications in data analysis and dissemination. At the same time the need of quantitative uncertainty evaluation is strongly requested in many aspects of the geological sciences and by the stakeholders. In many cases the starting point for 3D model building is the interpretation of seismic profiles that provide indirect information about the geology of the subsurface in the domain of time. The most problematic step in the 3D modelling construction is the conversion of the horizons and faults interpreted in time domain to the depth domain. In this step the dominant variable that could lead to significantly different results is the velocity. The knowledge of the subsurface velocities is related mainly to punctual data (sonic logs) that are often sparsely distributed in the areas covered by the seismic interpretation. The extrapolation of velocity information to wide extended horizons is thus a critical step to obtain a 3D model in depth that can be used for predictive purpose. In the EU-funded GeoMol Project, the availability of a dense network of seismic lines (confidentially provided by ENI S.p.A.) in the Central Po Plain, is paired with the presence of 136 well logs, but few of them have sonic logs and in some portion of the area the wells are very widely spaced. The depth conversion of the 3D model in time domain has been performed testing different strategies for the use and the interpolation of velocity data. The final model has been obtained using a 4 layer cake 3D instantaneous velocity model that considers both the initial velocity (v0) in every reference horizon and the gradient of velocity variation with depth (k). Using this method it is possible to consider the geological constraint given by the geometries of the horizons and the geo-statistical approach to the interpolation of velocities and gradient. Here we present an experiment based on the use of set of pseudo-wells obtained from the

Velocity Feedback Experiments

Directory of Open Access Journals (Sweden)

Chiu Choi

2017-02-01

Full Text Available Transient response such as ringing in a control system can be reduced or removed by velocity feedback. It is a useful control technique that should be covered in the relevant engineering laboratory courses. We developed velocity feedback experiments using two different low cost technologies, viz., operational amplifiers and microcontrollers. These experiments can be easily integrated into laboratory courses on feedback control systems or microcontroller applications. The intent of developing these experiments was to illustrate the ringing problem and to offer effective, low cost solutions for removing such problem. In this paper the pedagogical approach for these velocity feedback experiments was described. The advantages and disadvantages of the two different implementation of velocity feedback were discussed also.

Competition And Antitrust Law In Ecuadorian Constitution

OpenAIRE

Marcelo Marín Sevilla

2013-01-01

This work allows us to establish the Economic Constitution and the Competition Law (C.L) in the Constitution. Additionally, the paper analyzes whether the rules outlined in the C. L. and in doctrine are consistent and appropriate with the Constitution of Ecuador. The Competition and Antitrust Laws has rules for investigating and punishing the cartels, the abuses of power market (dominant position), the rules for merger control, the behaviors of Abuse of economic dependence, and unfair competi...

Health care law versus constitutional law.

Science.gov (United States)

Hall, Mark A

2013-04-01

National Federation of Independent Business v. Sebelius, the Supreme Court's ruling on the Patient Protection and Affordable Care Act, is a landmark decision - both for constitutional law and for health care law and policy. Others will study its implications for constitutional limits on a range of federal powers beyond health care. This article considers to what extent the decision is also about health care law, properly conceived. Under one view, health care law is the subdiscipline that inquires how courts and government actors take account of the special features of medicine that make legal or policy issues especially problematic - rather than regarding health care delivery and finance more generically, like most any other economic or social enterprise. Viewed this way, the opinions from the Court's conservative justices are mainly about general constitutional law principles. In contrast, Justice Ruth Bader Ginsburg's dissenting opinion for the four more liberal justices is just as much about health care law as it is about constitutional law. Her opinion gives detailed attention to the unique features of health care finance and delivery in order to inform her analysis of constitutional precedents and principles. Thus, the Court's multiple opinions give a vivid depiction of the compelling contrasts between communal versus individualistic conceptions of caring for those in need, and between health care and health insurance as ordinary commodities versus ones that merit special economic, social, and legal status.

Friction law and hysteresis in granular materials.

Science.gov (United States)

DeGiuli, E; Wyart, M

2017-08-29

The macroscopic friction of particulate materials often weakens as the flow rate is increased, leading to potentially disastrous intermittent phenomena including earthquakes and landslides. We theoretically and numerically study this phenomenon in simple granular materials. We show that velocity weakening, corresponding to a nonmonotonic behavior in the friction law, [Formula: see text], is present even if the dynamic and static microscopic friction coefficients are identical, but disappears for softer particles. We argue that this instability is induced by endogenous acoustic noise, which tends to make contacts slide, leading to faster flow and increased noise. We show that soft spots, or excitable regions in the materials, correspond to rolling contacts that are about to slide, whose density is described by a nontrivial exponent [Formula: see text] We build a microscopic theory for the nonmonotonicity of [Formula: see text], which also predicts the scaling behavior of acoustic noise, the fraction of sliding contacts [Formula: see text], and the sliding velocity, in terms of [Formula: see text] Surprisingly, these quantities have no limit when particles become infinitely hard, as confirmed numerically. Our analysis rationalizes previously unexplained observations and makes experimentally testable predictions.

Environmental law

International Nuclear Information System (INIS)

Anon.

1980-01-01

This pocketbook contains major federal regulations on environmental protection. They serve to protect and cultivate mankind's natural foundations of life, to preserve the environment. The environmental law is devided as follows: Constitutional law on the environment, common administrative law on the environment, special administrative law on the environment including conservation of nature and preservation of rural amenities, protection of waters, waste management, protection against nuisances, nuclear energy and radiation protection, energy conservation, protection against dangerous substances, private law relating to the environment, criminal law relating to the environment. (HSCH) [de

The poloidal OHM's law and a profile constraint in tokamaks

International Nuclear Information System (INIS)

Segre, S.E.; Zanza, V.

1991-01-01

Explicit use of the poloidal Ohm's law, together with the radial plasma velocity (obtained from the distribution of plasma sources), leads to a very general constraint on the possible radial profiles of plasma density and temperature. The constraint does not require any ad hoc assumption; it can place severe restrictions on the allowed profiles and is independent of energy and particle transport; also, it may be the underlying principle of profile consistency. The constraint is discussed in the framework of neoclassical theory, using results from the Frascati tokamak. (author). 23 refs, 7 figs

Electron velocity distributions near the earth's bow shock

International Nuclear Information System (INIS)

Feldman, W.C.; Anderson, R.C.; Bame, S.J.; Gary, S.P.; Gosling, J.T.; McComas, D.J.; Thomsen, M.F.; Paschmann, G.; Hoppe, M.M.

1983-01-01

A survey of two-dimensional electron velocity distributions, f(V), measured near the earth's bow shock using Los Alamos/Garching plasma instrumentation aboard ISEE 2 is presented. This survey provides clues to the mechanisms of electron thermalization within the shock and the relaxation of both the upsteam and downstream velocity distributions. First, near the foreshock boundary, fluxes of electrons having a power law shape at high energies backstream from the shock. Second, within the shock, cuts through f(V) along B. f(V), often show single maxima offset toward the magnetosheath by speeds comparable to, but larger than, the upstream thermal speed.Third, magnetosheath distributions generally have flat tops out to an energy, E 0 , with maxima substantially lower than that in the solar wind. Occasionally, cuts through f(V) along B show one and sometimes two small peaks at the edge of the flat tops making them appear concave upward. The electron distributions characteristic of these three regions are interpreted as arising from the effects of macroscopic (scale size comparable to or larger than the shock width) electric and magnetic fields and the subsequent effects of microscopic (scale size small in comparison with the shock width) fields. In particular, our results suggest that field-aligned instabilities are likely to be present in the earth's bow shock

On Carmeli's exotic use of the Lorentz transformation and on the velocity composition approach to special relativity

International Nuclear Information System (INIS)

de Beauregard, O.C.

1986-01-01

As shown by Ramarkrishnan, the faithful mapping, in the sense of Lie groups, of the real line onto the finite segment -1 < u < + 1 is u = tanh A, from which follows the ''relativistic velocity composition law'' w = (u + v)/(1 + uv) and the Lorentz-Poincare' transformation formulas. Composition of translations is merely one application of this. Carmeli has shown that composition of rotations is another one. There may be still others

A new maximum likelihood blood velocity estimator incorporating spatial and temporal correlation

DEFF Research Database (Denmark)

Schlaikjer, Malene; Jensen, Jørgen Arendt

2001-01-01

and space. This paper presents a new estimator (STC-MLE), which incorporates the correlation property. It is an expansion of the maximum likelihood estimator (MLE) developed by Ferrara et al. With the MLE a cross-correlation analysis between consecutive RF-lines on complex form is carried out for a range...... of possible velocities. In the new estimator an additional similarity investigation for each evaluated velocity and the available velocity estimates in a temporal (between frames) and spatial (within frames) neighborhood is performed. An a priori probability density term in the distribution...... of the observations gives a probability measure of the correlation between the velocities. Both the MLE and the STC-MLE have been evaluated on simulated and in-vivo RF-data obtained from the carotid artery. Using the MLE 4.1% of the estimates deviate significantly from the true velocities, when the performance...

The velocity of sound

International Nuclear Information System (INIS)

Beyer, R.T.

1985-01-01

The paper reviews the work carried out on the velocity of sound in liquid alkali metals. The experimental methods to determine the velocity measurements are described. Tables are presented of reported data on the velocity of sound in lithium, sodium, potassium, rubidium and caesium. A formula is given for alkali metals, in which the sound velocity is a function of shear viscosity, atomic mass and atomic volume. (U.K.)

Law of nonlinear flow in saturated clays and radial consolidation

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

It was derived that micro-scale amount level of average pore radius of clay changed from 0.01 to 0.1 micron by an equivalent concept of flow in porous media. There is good agreement between the derived results and test ones. Results of experiments show that flow in micro-scale pore of saturated clays follows law of nonlinear flow. Theoretical analyses demonstrate that an interaction of solid-liquid interfaces varies inversely with permeability or porous radius. The interaction is an important reason why nonlinear flow in saturated clays occurs. An exact mathematical model was presented for nonlinear flow in micro-scale pore of saturated clays. Dimension and physical meanings of parameters of it are definite. A new law of nonlinear flow in saturated clays was established. It can describe characteristics of flow curve of the whole process of the nonlinear flow from low hydraulic gradient to high one. Darcy law is a special case of the new law. A mathematical model was presented for consolidation of nonlinear flow in radius direction in saturated clays with constant rate based on the new law of nonlinear flow. Equations of average mass conservation and moving boundary, and formula of excess pore pressure distribution and average degree of consolidation for nonlinear flow in saturated clay were derived by using an idea of viscous boundary layer, a method of steady state in stead of transient state and a method of integral of an equation. Laws of excess pore pressure distribution and changes of average degree of consolidation with time were obtained. Results show that velocity of moving boundary decreases because of the nonlinear flow in saturated clay. The results can provide geology engineering and geotechnical engineering of saturated clay with new scientific bases. Calculations of average degree of consolidation of the Darcy flow are a special case of that of the nonlinear flow.

THE STAR FORMATION LAWS OF EDDINGTON-LIMITED STAR-FORMING DISKS

Energy Technology Data Exchange (ETDEWEB)

Ballantyne, D. R.; Armour, J. N.; Indergaard, J., E-mail: david.ballantyne@physics.gatech.edu [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

2013-03-10

Two important avenues into understanding the formation and evolution of galaxies are the Kennicutt-Schmidt (K-S) and Elmegreen-Silk (E-S) laws. These relations connect the surface densities of gas and star formation ({Sigma}{sub gas} and {Sigma}-dot{sub *}, respectively) in a galaxy. To elucidate the K-S and E-S laws for disks where {Sigma}{sub gas} {approx}> 10{sup 4} M{sub Sun} pc{sup -2}, we compute 132 Eddington-limited star-forming disk models with radii spanning tens to hundreds of parsecs. The theoretically expected slopes ( Almost-Equal-To 1 for the K-S law and Almost-Equal-To 0.5 for the E-S relation) are relatively robust to spatial averaging over the disks. However, the star formation laws exhibit a strong dependence on opacity that separates the models by the dust-to-gas ratio that may lead to the appearance of a erroneously large slope. The total infrared luminosity (L{sub TIR}) and multiple carbon monoxide (CO) line intensities were computed for each model. While L{sub TIR} can yield an estimate of the average {Sigma}-dot{sub *} that is correct to within a factor of two, the velocity-integrated CO line intensity is a poor proxy for the average {Sigma}{sub gas} for these warm and dense disks, making the CO conversion factor ({alpha}{sub CO}) all but useless. Thus, observationally derived K-S and E-S laws at these values of {Sigma}{sub gas} that uses any transition of CO will provide a poor measurement of the underlying star formation relation. Studies of the star formation laws of Eddington-limited disks will require a high-J transition of a high density molecular tracer, as well as a sample of galaxies with known metallicity estimates.

Critical Velocity for Shear Localization in A Mature Mylonitic Rock Analogue

Science.gov (United States)

Takahashi, M.; van den Ende, M.; Niemeijer, A. R.; Spiers, C. J.

2016-12-01

Highly localized slip zones, seen within ductile shear zones developed in nature, such as pseudotachylite bands occurring within mylonites, are widely recognized as evidence for earthquake nucleation and/or propagation within and overprinting the ductile regime. To understand brittle/frictional localization processes in ductile shear zones and to connect these to earthquake nucleation and propagation processes, we performed large velocity step-change tests on a brine-saturated, 80:20 (wt. %) halite and muscovite gouge mixture, after forming a mature mylonitic structure through pressure solution creep at low-velocity. The sharp increase in sliding strength that occurs in response to an instantaneous upward velocity-step (direct effect) is an important parameter in determining the potential for and nature of seismic rupture nucleation. We obtained reproducible results regarding low velocity mechanical behavior compared with previous work of Niemeijer and Spiers, [2006], but also obtained new insights into the effects of sudden increases in slip velocity on localization and strength evolution, at velocities above a specific critical velocity Vc ( 20 μm/sec). We found that once a ductile, mylonitic structure has developed in a shear zone, subsequent cataclastic deformation at high velocity (> Vc) is consistently localized in a narrow zone characterized by fine grains of halite aligned in arrays between foliated muscovite Due to this intense localization, structures presumably developed under low velocity conditions were still preserved in large parts of the gouge body. This switch to localized deformation is controlled by the imposed velocity, and becomes most apparent at velocities over Vc. In addition, the direct effect a decreases rapidly when the velocity exceeds Vc. This implies that slip can localize and accelerate towards seismic velocities more or less instantly once Vc is exceeded. Obtaining a measure for Vc in natural faults is therefore of key importance

Development, implementation and assessment of specific closure laws for inverted-annular film-boiling in a two-fluid model

International Nuclear Information System (INIS)

Cachard, F. de

1994-10-01

Inverted-annular film-boiling (IAFB) is one of the post-burnout heat transfer modes taking place, in particular, during the reflooding phase of the loss-of-coolant accident, when the liquid at the quench front is subcooled. Under IAFB conditions, a continuous liquid core is separated from the wall by a superheated vapour film. The heat transfer rate in IAFB is influenced by the flooding rate, liquid subcooling, pressure, and the wall geometry and temperature. These influences can be accounted by a two-fluid model with physically sound closure laws for mass, momentum and heat transfer between the wall, the vapour film, the vapour-liquid interface, and the liquid core. The applicability of existing IAFB two-fluid models is limited. This is attributed to shortcomings in the description of heat transfer within the liquid core, to use of certain correlations outside their validity range, and to a limited use of experimental information on IAFB. The usual approach has been to develop models employing generally applicable closure laws including, however, adjustable parameters, and to adjust these using global experimental results. The present approach has been to develop IAFB-specific closure laws in such a form that they could be adjusted separately using detailed, IAFB-relevant, experimental result. Steady-state results, including heat flux, wall temperature and void fraction data have been used for the adjustment. A key issue in IAFB modeling is to predict how the heat flux reaching the vapour-liquid interface is split into a liquid heating term and a vaporization term. In the model proposed, convective liquid heating is related to the liquid velocity relative to the interface, and not to the absolute liquid velocity, as in previous models. This relative velocity is deduced from the interfacial shear stress, using the liquid-interface friction law. With this modification, the prediction of the experimental trends is greatly improved. (author) figs., tabs., refs

The Delinquencies of Juvenile Law: A Natural Law Analysis

Directory of Open Access Journals (Sweden)

Ellis Washington

2010-07-01

Full Text Available This article is a substantive analysis tracing the legal, philosophical, social, historical, jurisprudence and political backgrounds of juvenile law, which is an outgrowth of the so-calledProgressive movement - a popular social and political movement of the late nineteenth and early twentieth century. I also trace how this socio-political cause célèbre became a fixture in Americanculture and society due to existential child labor abuses which progressive intellectuals used as a pretext to codify juvenile law in federal law and in statutory law in all 50 states by 1925. Moreover the dubious social science and Machiavellian political efforts that created the juvenile justice system out of whole cloth has done much more harm to the Constitution and to the children it was mandated to protect than any of the Progressive ideas initially envisioned rooted in Positive Law (separation of law and morals. Finally, I present am impassioned argument for congressional repeal of all juvenile case law and statutes because they are rooted in Positive Law, contrary to Natural Law (integration of law and morals, the original intent of the constitutional Framers and are therefore patently unconstitutional.

A GLOBAL MODEL OF THE LIGHT CURVES AND EXPANSION VELOCITIES OF TYPE II-PLATEAU SUPERNOVAE

Energy Technology Data Exchange (ETDEWEB)

Pejcha, Ondřej [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08540 (United States); Prieto, Jose L., E-mail: pejcha@astro.princeton.edu [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441 Santiago (Chile)

2015-02-01

We present a new self-consistent and versatile method that derives photospheric radius and temperature variations of Type II-Plateau supernovae based on their expansion velocities and photometric measurements. We apply the method to a sample of 26 well-observed, nearby supernovae with published light curves and velocities. We simultaneously fit ∼230 velocity and ∼6800 mag measurements distributed over 21 photometric passbands spanning wavelengths from 0.19 to 2.2 μm. The light-curve differences among the Type II-Plateau supernovae are well modeled by assuming different rates of photospheric radius expansion, which we explain as different density profiles of the ejecta, and we argue that steeper density profiles result in flatter plateaus, if everything else remains unchanged. The steep luminosity decline of Type II-Linear supernovae is due to fast evolution of the photospheric temperature, which we verify with a successful fit of SN 1980K. Eliminating the need for theoretical supernova atmosphere models, we obtain self-consistent relative distances, reddenings, and nickel masses fully accounting for all internal model uncertainties and covariances. We use our global fit to estimate the time evolution of any missing band tailored specifically for each supernova, and we construct spectral energy distributions and bolometric light curves. We produce bolometric corrections for all filter combinations in our sample. We compare our model to the theoretical dilution factors and find good agreement for the B and V filters. Our results differ from the theory when the I, J, H, or K bands are included. We investigate the reddening law toward our supernovae and find reasonable agreement with standard R{sub V}∼3.1 reddening law in UBVRI bands. Results for other bands are inconclusive. We make our fitting code publicly available.

VOLUNTAS - SCIENTIA - IGNORANTIA AND THE ADDITIONAL LIABILITY OF HEAD OF FAMILY/ SLAVE OWNER FOR THE CONTRACTUAL OBLIGATIONS MADE BY PERSONS UNDER HIS POWER (ALIENI IURIS IN ROMAN LAW

Directory of Open Access Journals (Sweden)

Aldona R. Jurewicz

2016-12-01

Full Text Available In Roman law the liability for contractual obligations was initially based on the objective premise - the creation of the vinculum iuris (legal bond. During the development of the system of formulary procedure the praetor began to consider the subjective premises of obligation liability, such as voluntas,scientia or ignorantia agens. As for the additional liability in Roman law, this kind of liability may have resulted from the ignorantia, scientia or demonstrated voluntas of head of family/slave owner. These subjective bias’s of the contractual liability diversified its scope - from the lesser degree (based on de peculio, de in rem verso through tightened (on the base of in tributum vocariup to most wide scope of liability (in solidum based on the voluntas of the head of family/slave owner. The voluntas should be always demonstrated, in the case of scientia the declaration of will was needed only in the case of opposition from the head of family/slave owner. Precise differentiation of the subjective bases of the additional liability of superior is the effect of the interpretation of the edict of praetor urbanus by classical jurists.

Velocity-space tomography of the fast-ion distribution function

DEFF Research Database (Denmark)

Jacobsen, Asger Schou; Salewski, Mirko; Geiger, Benedikt

2013-01-01

probes certain regions in velocity-space, determined by the geometry of the set-up. Exploiting this, the fast-ion distribution function can be inferred using a velocity-space tomography method. This poster contains a tomography calculated from measured spectra from three different FIDA views at ASDEX......Fast ions play an important role in heating the plasma in a magnetic confinement fusion device. Fast-ion Dα(FIDA) spectroscopy diagnoses fast ions in small measurement volumes. Spectra measured by a FIDA diagnostic can be related to the 2D fast-ion velocity distribution function. A single FIDA view...... Upgrade. The quality of the tomography improves with the number of FIDA views simultaneously measuring the same volume. To investigate the potential benefits of including additional views (up to 18), tomographies are inferred from synthetic spectra calculated from a simulated distribution function...

VeLoc: Finding Your Car in Indoor Parking Structures

Directory of Open Access Journals (Sweden)

Ruipeng Gao

2018-05-01

Full Text Available While WiFi-based indoor localization is attractive, there are many indoor places without WiFi coverage with a strong demand for localization capability. This paper describes a system and associated algorithms to address the indoor vehicle localization problem without the installation of additional infrastructure. In this paper, we propose VeLoc, which utilizes the sensor data of smartphones in the vehicle together with the floor map of the parking structure to track the vehicle in real time. VeLoc simultaneously harnesses constraints imposed by the map and environment sensing. All these cues are codified into a novel augmented particle filtering framework to estimate the position of the vehicle. Experimental results show that VeLoc performs well when even the initial position and the initial heading direction of the vehicle are completely unknown.

Nerve conduction velocity

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/003927.htm Nerve conduction velocity To use the sharing features on this page, please enable JavaScript. Nerve conduction velocity (NCV) is a test to see ...

Nonlocal symmetries and nonlocal conservation laws of Maxwell's equations

International Nuclear Information System (INIS)

Anco, S.C.; Bluman, G.

1997-01-01

Nonlocal symmetries are obtained for Maxwell's equations in three space-time dimensions through the use of two potential systems involving scalar and vector potentials for the electromagnetic field. Corresponding nonlocal conservation laws are derived from these symmetries. The conservation laws yield nine functionally independent constants of motion which cannot be expressed in terms of the constants of motion arising from local conservation laws for space-time symmetries. These nine constants of motion represent additional conserved quantities for the electromagnetic field in three space endash time dimensions. copyright 1997 American Institute of Physics

A study of the river velocity measurement techniques and analysis methods

Science.gov (United States)

Chung Yang, Han; Lun Chiang, Jie

2013-04-01

Velocity measurement technology can be traced back to the pitot tube velocity measurement method in the 18th century and today's velocity measurement technology use the acoustic and radar technology, with the Doppler principle developed technology advances, in order to develop the measurement method is more suitable for the measurement of velocity, the purpose is to get a more accurate measurement data and with the surface velocity theory, the maximum velocity theory and the indicator theory to obtain the mean velocity. As the main research direction of this article is to review the literature of the velocity measurement techniques and analysis methods, and to explore the applicability of the measurement method of the velocity measurement instruments, and then to describe the advantages and disadvantages of the different mean velocity profiles analysis method. Adequate review of the references of this study will be able to provide a reference for follow-up study of the velocity measurement. Review velocity measurement literature that different velocity measurement is required to follow the different flow conditions measured be upgraded its accuracy, because each flow rate measurement method has its advantages and disadvantages. Traditional velocity instrument can be used at low flow and RiverRAD microwave radar or imaging technology measurement method may be applied in high flow. In the tidal river can use the ADCP to quickly measure river vertical velocity distribution. In addition, urban rivers may be used the CW radar to set up on the bridge, and wide rivers can be used RiverRAD microwave radar to measure the velocities. Review the relevant literature also found that using Ultrasonic Doppler Current Profiler with the Chiu's theory to the velocity of observing automation work can save manpower and resources to improve measurement accuracy, reduce the risk of measurement, but the great variability of river characteristics in Taiwan and a lot of drifting floating

Second order limit laws for occupation times of the fractional Brownian motion

OpenAIRE

Xu, Fangjun

2013-01-01

We prove second order limit laws for (additive) functionals of the $d$-dimensional fractional Brownian motion with Hurst index $H=\\frac{1}{d}$, using the method of moments, extending the Kallianpur-Robbins law.

Dynamics of the standard deviations of three wind velocity components from the data of acoustic sounding

Science.gov (United States)

Krasnenko, N. P.; Kapegesheva, O. F.; Shamanaeva, L. G.

2017-11-01

Spatiotemporal dynamics of the standard deviations of three wind velocity components measured with a mini-sodar in the atmospheric boundary layer is analyzed. During the day on September 16 and at night on September 12 values of the standard deviation changed for the x- and y-components from 0.5 to 4 m/s, and for the z-component from 0.2 to 1.2 m/s. An analysis of the vertical profiles of the standard deviations of three wind velocity components for a 6-day measurement period has shown that the increase of σx and σy with altitude is well described by a power law dependence with exponent changing from 0.22 to 1.3 depending on the time of day, and σz depends linearly on the altitude. The approximation constants have been found and their errors have been estimated. The established physical regularities and the approximation constants allow the spatiotemporal dynamics of the standard deviation of three wind velocity components in the atmospheric boundary layer to be described and can be recommended for application in ABL models.

Determination of velocity correction factors for real-time air velocity monitoring in underground mines

OpenAIRE

Zhou, Lihong; Yuan, Liming; Thomas, Rick; Iannacchione, Anthony

2017-01-01

When there are installations of air velocity sensors in the mining industry for real-time airflow monitoring, a problem exists with how the monitored air velocity at a fixed location corresponds to the average air velocity, which is used to determine the volume flow rate of air in an entry with the cross-sectional area. Correction factors have been practically employed to convert a measured centerline air velocity to the average air velocity. However, studies on the recommended correction fac...

Scaling Law for Cross-stream Diffusion in Microchannels under Combined Electroosmotic and Pressure Driven Flow.

Science.gov (United States)

Song, Hongjun; Wang, Yi; Pant, Kapil

2013-01-01

This paper presents an analytical study of the cross-stream diffusion of an analyte in a rectangular microchannel under combined electroosmotic flow (EOF) and pressure driven flow to investigate the heterogeneous transport behavior and spatially-dependent diffusion scaling law. An analytical model capable of accurately describing 3D steady-state convection-diffusion in microchannels with arbitrary aspect ratios is developed based on the assumption of the thin Electric Double Layer (EDL). The model is verified against high-fidelity numerical simulation in terms of flow velocity and analyte concentration profiles with excellent agreement (parametric analysis is then undertaken to interrogate the effect of the combined flow velocity field on the transport behavior in both the positive pressure gradient (PPG) and negative pressure gradient (NPG) cases. For the first time, the evolution from the spindle-shaped concentration profile in the PPG case, via the stripe-shaped profile (pure EOF), and finally to the butterfly-shaped profile in the PPG case is obtained using the analytical model along with a quantitative depiction of the spatially-dependent diffusion layer thickness and scaling law across a wide range of the parameter space.

Inertial Navigation System/Doppler Velocity Log (INS/DVL Fusion with Partial DVL Measurements

Directory of Open Access Journals (Sweden)

Asaf Tal

2017-02-01

Full Text Available The Technion autonomous underwater vehicle (TAUV is an ongoing project aiming to develop and produce a small AUV to carry on research missions, including payload dropping, and to demonstrate acoustic communication. Its navigation system is based on an inertial navigation system (INS aided by a Doppler velocity log (DVL, magnetometer, and pressure sensor (PS. In many INSs, such as the one used in TAUV, only the velocity vector (provided by the DVL can be used for aiding the INS, i.e., enabling only a loosely coupled integration approach. In cases of partial DVL measurements, such as failure to maintain bottom lock, the DVL cannot estimate the vehicle velocity. Thus, in partial DVL situations no velocity data can be integrated into the TAUV INS, and as a result its navigation solution will drift in time. To circumvent that problem, we propose a DVL-based vehicle velocity solution using the measured partial raw data of the DVL and additional information, thereby deriving an extended loosely coupled (ELC approach. The implementation of the ELC approach requires only software modification. In addition, we present the TAUV six degrees of freedom (6DOF simulation that includes all functional subsystems. Using this simulation, the proposed approach is evaluated and the benefit of using it is shown.

Velocity Profile measurements in two-phase flow using multi-wave sensors

Science.gov (United States)

Biddinika, M. K.; Ito, D.; Takahashi, H.; Kikura, H.; Aritomi, M.

2009-02-01

Two-phase flow has been recognized as one of the most important phenomena in fluid dynamics. In addition, gas-liquid two-phase flow appears in various industrial fields such as chemical industries and power generations. In order to clarify the flow structure, some flow parameters have been measured by using many effective measurement techniques. The velocity profile as one of the important flow parameter, has been measured by using ultrasonic velocity profile (UVP) technique. This technique can measure velocity distributions along a measuring line, which is a beam formed by pulse ultrasounds. Furthermore, a multi-wave sensor can measure the velocity profiles of both gas and liquid phase using UVP method. In this study, two types of multi-wave sensors are used. A sensor has cylindrical shape, and another one has square shape. The piezoelectric elements of each sensor have basic frequencies of 8 MHz for liquid phase and 2 MHz for gas phase, separately. The velocity profiles of air-water bubbly flow in a vertical rectangular channel were measured by using these multi-wave sensors, and the validation of the measuring accuracy was performed by the comparison between the velocity profiles measured by two multi-wave sensors.

Velocity Profile measurements in two-phase flow using multi-wave sensors

International Nuclear Information System (INIS)

Biddinika, M K; Ito, D; Takahashi, H; Kikura, H; Aritomi, M

2009-01-01

Two-phase flow has been recognized as one of the most important phenomena in fluid dynamics. In addition, gas-liquid two-phase flow appears in various industrial fields such as chemical industries and power generations. In order to clarify the flow structure, some flow parameters have been measured by using many effective measurement techniques. The velocity profile as one of the important flow parameter, has been measured by using ultrasonic velocity profile (UVP) technique. This technique can measure velocity distributions along a measuring line, which is a beam formed by pulse ultrasounds. Furthermore, a multi-wave sensor can measure the velocity profiles of both gas and liquid phase using UVP method. In this study, two types of multi-wave sensors are used. A sensor has cylindrical shape, and another one has square shape. The piezoelectric elements of each sensor have basic frequencies of 8 MHz for liquid phase and 2 MHz for gas phase, separately. The velocity profiles of air-water bubbly flow in a vertical rectangular channel were measured by using these multi-wave sensors, and the validation of the measuring accuracy was performed by the comparison between the velocity profiles measured by two multi-wave sensors.

Measurements of the laminar burning velocity of hydrogen-air premixed flames

Energy Technology Data Exchange (ETDEWEB)

Pareja, Jhon; Burbano, Hugo J. [Science and Technology of Gases and Rational Use of Energy Group, Faculty of Engineering, University of Antioquia, Calle 67 N 53, 108 Bloque 20, 447 Medellin (Colombia); Ogami, Yasuhiro [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

2010-02-15

Experimental and numerical studies on laminar burning velocities of hydrogen-air mixtures were performed at standard pressure and room temperature varying the equivalence ratio from 0.8 to 3.0. The flames were generated using a contoured slot-type nozzle burner (4 mm x 10 mm). Measurements of laminar burning velocity were conducted using particle tracking velocimetry (PTV) combined with Schlieren photography. This technique provides the information of instantaneous local burning velocities in the whole region of the flame front, and laminar burning velocities were determined using the mean value of local burning velocities in the region of non-stretch. Additionally, average laminar burning velocities were determined using the angle method and compared with the data obtained with the PTV method. Numerical calculations were also conducted using detailed reaction mechanisms and transport properties. The experimental results from the PTV method are in good agreement with the numerical results at every equivalence ratio of the range of study. Differences between the results obtained with the angle method and those with the PTV method are reasonably small when the effects of flame stretch and curvature are reduced by using a contoured slot-type nozzle. (author)

Tyre effective radius and vehicle velocity estimation: a variable structure observer solution

International Nuclear Information System (INIS)

El Tannoury, C.; Plestan, F.; Moussaoui, S.; ROMANi, N. RENAULT

2011-01-01

This paper proposes an application of a variable structure observer for wheel effective radius and velocity of automotive vehicles. This observer is based on high order sliding approach allowing robustness and finite time convergence. Its originality consists in assuming a nonlinear relation between the slip ratio and the friction coefficient and providing an estimation of both variables, wheel radius and vehicle velocity, from measurement of wheel angular velocity and torque. These signals being available on major modern vehicle CAN (Controller Area Network) buses, this system does not require additional sensors. A simulation example is given to illustrate the relevance of this approach.

In-vivo evaluation of three ultrasound vector velocity techniques with MR angiography

DEFF Research Database (Denmark)

Hansen, Kristoffer Lindskov; Udesen, Jesper; Oddershede, Niels

2008-01-01

In conventional Doppler ultrasound (US) the blood velocity is only estimated along the US beam direction. The estimate is angle corrected assuming laminar flow parallel to the vessel boundaries. As the now in the vascular system never is purely laminar, the velocities estimated with conventional...... additionally constructed and mean differences for the three comparisons were: DB/MRA = 0.17 ml; STA/MRA = 0.07 ml; TO/MRA = 0.24 ml. The three US vector velocity techniques yield quantitative insight in to flow dynamics and can potentially give the clinician a powerful tool in cardiovascular disease assessment....

Additive functionals and excursions of Kuznetsov processes

Directory of Open Access Journals (Sweden)

Hacène Boutabia

2005-01-01

semigroup of transition. In this paper, we give the excursion laws of (Xtt∈ℝ+ conditioned on the strict past and future without duality hypothesis. We study excursions of a general regenerative system and of a regenerative system consisting of the closure of the set of times the regular points of B are visited. In both cases, those conditioned excursion laws depend only on two points Xg− and Xd, where ]g,d[ is an excursion interval of the regenerative set M. We use the (FDt-predictable exit system to bring together the isolated points of M and its perfect part and replace the classical optional exit system. This has been a subject in literature before (e.g., Kaspi (1988 under the classical duality hypothesis. We define an “additive functional” for (Ytt∈ℝ with B, we generalize the laws cited before to (Ytt∈ℝ, and we express laws of pairs of excursions.

Law of Conservation of Muons

Science.gov (United States)

Feinberg, G.; Weinberg, S.

1961-02-01

A multiplicative selection rule for mu meson-electron transitions is proposed. A "muon parity" = -1 is considered for the muon and its neutrino, while the "muon parity" for all other particles is +1. The selection rule then states that (-1) exp(no. of initial (-1) parity particles) = (-1) exp(no. of final (-1) parity particles). Several reactions that are forbidden by an additive law but allowed by the multiplicative law are suggested; these reactions include mu{sup +} .> e{sup +} + nu{sub mu} + {ovr nu}{sub e}, e{sup -} + e{sup -} .> mu{sup -} + mu{sup -}, and muonium .> antimuonium (mu{sup +} + e{sup -} .> mu{sup -} + e{sup +}). An intermediate-boson hypothesis is suggested. (T.F.H.)

Velocity of climate change algorithms for guiding conservation and management.

Science.gov (United States)

Hamann, Andreas; Roberts, David R; Barber, Quinn E; Carroll, Carlos; Nielsen, Scott E

2015-02-01

The velocity of climate change is an elegant analytical concept that can be used to evaluate the exposure of organisms to climate change. In essence, one divides the rate of climate change by the rate of spatial climate variability to obtain a speed at which species must migrate over the surface of the earth to maintain constant climate conditions. However, to apply the algorithm for conservation and management purposes, additional information is needed to improve realism at local scales. For example, destination information is needed to ensure that vectors describing speed and direction of required migration do not point toward a climatic cul-de-sac by pointing beyond mountain tops. Here, we present an analytical approach that conforms to standard velocity algorithms if climate equivalents are nearby. Otherwise, the algorithm extends the search for climate refugia, which can be expanded to search for multivariate climate matches. With source and destination information available, forward and backward velocities can be calculated allowing useful inferences about conservation of species (present-to-future velocities) and management of species populations (future-to-present velocities). © 2014 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

The incorporation of public international law into municipal law and ...

African Journals Online (AJOL)

Monism and dualism represent two different approaches towards the relationship between public international law and municipal law. While the former views public international law and municipal law as a single legal system, the latter regards these two areas of law as separate and distinct legal systems that exist ...

Existence of k⁻¹ power-law scaling in the equilibrium regions of wall-bounded turbulence explained by Heisenberg's eddy viscosity.

Science.gov (United States)

Katul, Gabriel G; Porporato, Amilcare; Nikora, Vladimir

2012-12-01

The existence of a "-1" power-law scaling at low wavenumbers in the longitudinal velocity spectrum of wall-bounded turbulence was explained by multiple mechanisms; however, experimental support has not been uniform across laboratory studies. This letter shows that Heisenberg's eddy viscosity approach can provide a theoretical framework that bridges these multiple mechanisms and explains the elusiveness of the "-1" power law in some experiments. Novel theoretical outcomes are conjectured about the role of intermittency and very-large scale motions in modifying the k⁻¹ scaling.

A 'Scottish Poor Law of Lunacy'? Poor Law, Lunacy Law and Scotland's parochial asylums.

Science.gov (United States)

Farquharson, Lauren

2017-03-01

Scotland's parochial asylums are unfamiliar institutional spaces. Representing the concrete manifestation of the collision between two spheres of legislation, the Poor Law and the Lunacy Law, six such asylums were constructed in the latter half of the nineteenth century. These sites expressed the enduring mandate of the Scottish Poor Law 1845 over the domain of 'madness'. They were institutions whose very existence was fashioned at the directive of the local arm of the Poor Law, the parochial board, and they constituted a continuing 'Scottish Poor Law of Lunacy'. Their origins and operation significantly subverted the intentions and objectives of the Lunacy Act 1857, the aim of which had been to institute a public district asylum network with nationwide coverage.

Premotor neurons encode torsional eye velocity during smooth-pursuit eye movements

Science.gov (United States)

Angelaki, Dora E.; Dickman, J. David

2003-01-01

Responses to horizontal and vertical ocular pursuit and head and body rotation in multiple planes were recorded in eye movement-sensitive neurons in the rostral vestibular nuclei (VN) of two rhesus monkeys. When tested during pursuit through primary eye position, the majority of the cells preferred either horizontal or vertical target motion. During pursuit of targets that moved horizontally at different vertical eccentricities or vertically at different horizontal eccentricities, eye angular velocity has been shown to include a torsional component the amplitude of which is proportional to half the gaze angle ("half-angle rule" of Listing's law). Approximately half of the neurons, the majority of which were characterized as "vertical" during pursuit through primary position, exhibited significant changes in their response gain and/or phase as a function of gaze eccentricity during pursuit, as if they were also sensitive to torsional eye velocity. Multiple linear regression analysis revealed a significant contribution of torsional eye movement sensitivity to the responsiveness of the cells. These findings suggest that many VN neurons encode three-dimensional angular velocity, rather than the two-dimensional derivative of eye position, during smooth-pursuit eye movements. Although no clear clustering of pursuit preferred-direction vectors along the semicircular canal axes was observed, the sensitivity of VN neurons to torsional eye movements might reflect a preservation of similar premotor coding of visual and vestibular-driven slow eye movements for both lateral-eyed and foveate species.

Contesting sharia: state law, decentralization and Minangkabau custom

OpenAIRE

Huda, Yasrul

2013-01-01

This book explains how Sharia, commonly called Perda Sharia (Sharia by-law) in Indonesia, was legislated on the provincial, regional and municipal level in West Sumatra. This process began after the government started a decentralization policy in 2000. Although the law of local autonomy prescribes that religious matters are excluded from the authority of local government, the legislation of Sharia by local authorities is justified by the argument that Sharia, in addition to Minangkabau custom...

The Existence of Customary Law in the Polemics of Positive Law – a Study From the Perspective of Constitutional Law

OpenAIRE

Saleh, M

2013-01-01

As a member of the law family, the Adat law is one form of positive law which plays particular role and contribution in the making process of the whole positive law in Indonesia. Existence of Adat law in the constitutional of Indonesia painted its own color. As one of the oldest customary law in the life of local community Adat law has become the seed and formatting idea of Indonesia's national law where Adat Law has widely influenced other positive law.

Modifications to the pulsar kick velocity due to magnetic interactions in dense plasma

International Nuclear Information System (INIS)

Adhya, S P; Roy, P K; Dutt-Mazumder, A K

2014-01-01

In this work we calculate the pulsar kick velocity of a magnetized neutron star (NS) composed of a degenerate quark matter core with non-Fermi liquid (NFL) correction. Both the leading order (LO) and next to LO (NLO) corrections to the kick velocity have been incorporated. In addition, the NFL corrections to the specific heat of magnetized quark matter have been presented. This has been taken into account to calculate the kick velocity of the NS. The results show a significant departure from the normal Fermi liquid estimates. The relation between radius and temperature has been shown with a kick velocity of 100 km s −1 with and without NFL corrections. (paper)

Kinematic Modeling of Normal Voluntary Mandibular Opening and Closing Velocity-Initial Study.

Science.gov (United States)

Gawriołek, Krzysztof; Gawriołek, Maria; Komosa, Marek; Piotrowski, Paweł R; Azer, Shereen S

2015-06-01

Determination and quantification of voluntary mandibular velocity movement has not been a thoroughly studied parameter of masticatory movement. This study attempted to objectively define kinematics of mandibular movement based on numerical (digital) analysis of the relations and interactions of velocity diagram records in healthy female individuals. Using a computerized mandibular scanner (K7 Evaluation Software), 72 diagrams of voluntary mandibular velocity movements (36 for opening, 36 for closing) for women with clinically normal motor and functional activities of the masticatory system were recorded. Multiple measurements were analyzed focusing on the curve for maximum velocity records. For each movement, the loop of temporary velocities was determined. The diagram was then entered into AutoCad calculation software where movement analysis was performed. The real maximum velocity values on opening (Vmax ), closing (V0 ), and average velocity values (Vav ) as well as movement accelerations (a) were recorded. Additionally, functional (A1-A2) and geometric (P1-P4) analysis of loop constituent phases were performed, and the relations between the obtained areas were defined. Velocity means and correlation coefficient values for various velocity phases were calculated. The Wilcoxon test produced the following maximum and average velocity results: Vmax = 394 ± 102, Vav = 222 ± 61 for opening, and Vmax = 409 ± 94, Vav = 225 ± 55 mm/s for closing. Both mandibular movement range and velocity change showed significant variability achieving the highest velocity in P2 phase. Voluntary mandibular velocity presents significant variations between healthy individuals. Maximum velocity is obtained when incisal separation is between 12.8 and 13.5 mm. An improved understanding of the patterns of normal mandibular movements may provide an invaluable diagnostic aid to pathological changes within the masticatory system. © 2014 by the American College of Prosthodontists.

THE INTERFERENCE OF EUROPEAN UNION LAW WITH PUBLIC INTERNATIONAL LAW

Directory of Open Access Journals (Sweden)

ROXANA-MARIANA POPESCU

2011-04-01

Full Text Available The European Union Law is an unique legal phenomenon developed in the process of European integration within the framework of the European Communities and the European Union; a result of the implementation of the supranational authority of the European institutions. The European Union law is a specific legal system having independent sources and principles that developed at the border-line of international law and domestic law of the EU’s Member States. The authonomy of the European Union law is affirmed by a case-law of the Court of Justice of the European Union.The European Union has its own legal order which is separate from international law and forms an integral part of the legal systems of the Member States. The legal order of the Union is founded on various different sources of law. The different nature of these sources has imposed a hierarchy among them. At the pinnacle of this hierarchy we find primary law, represented by the Treaties and general legal principles, followed by international treaties concluded by the Union and secondary law founded on the Treaties.

Impacts of cloud flare-ups on hurricane intensity resulting from departures from balance laws

Directory of Open Access Journals (Sweden)

T. N. Krishnamurti

2012-05-01

Full Text Available Cloud flare-ups along the inner eye wall of a hurricane lead to enhancement of cloud scale divergence, which in turn leads to a large local enhancement of the departure from balance laws and can lead to local supergradient winds. This scenario is tested using the results from a mesoscale microphysical model at horizontal resolution of 1.33 km for the simulation of hurricane Katrina. Rainwater mixing ratio tags growing cloud elements. The departure from balance laws includes terms such as the local, horizontal and vertical advections of divergence, divergence square and a term invoking the gradient of vertical velocity. It is noted that these terms collectively contribute to a substantial local enhancement of the departure from balance laws. Departures from balance laws are related to the radial gradient wind imbalances in a storm-centred coordinate. In this study, several examples, from the hurricane Katrina simulations, that display this scenario of rapid intensification are illustrated. Organisation of convection in the azimuthal direction seems important for the hurricane scale; cloud flare-ups away from such regions of azimuthal organisation fail to contribute to this scenario for the overall intensification of the hurricane.

Law on the web a guide for students and practitioners

CERN Document Server

Stein, Stuart

2014-01-01

Law on the Web is ideal for anyone who wants to access Law Internet resources quickly and efficiently without becoming an IT expert. The emphasis throughout is on the location of high quality law Internet resources for learning, teaching and research, from among the billions of publicly accessible Web pages. The book is structured so that it will be found useful by both beginners and intermediate level users, and be of continuing use over the course of higher education studies. In addition to extensive coverage on locating files and Web sites, Part III provides a substantial and annotated list of high quality resources for law students.

A radial velocity survey of the Carina Nebula's O-type stars

Science.gov (United States)

Kiminki, Megan M.; Smith, Nathan

2018-03-01

We have obtained multi-epoch observations of 31 O-type stars in the Carina Nebula using the CHIRON spectrograph on the CTIO/SMARTS 1.5-m telescope. We measure their radial velocities to 1-2 km s-1 precision and present new or updated orbital solutions for the binary systems HD 92607, HD 93576, HDE 303312, and HDE 305536. We also compile radial velocities from the literature for 32 additional O-type and evolved massive stars in the region. The combined data set shows a mean heliocentric radial velocity of 0.6 km s-1. We calculate a velocity dispersion of ≤9.1 km s-1, consistent with an unbound, substructured OB association. The Tr 14 cluster shows a marginally significant 5 km s-1 radial velocity offset from its neighbor Tr 16, but there are otherwise no correlations between stellar position and velocity. The O-type stars in Cr 228 and the South Pillars region have a lower velocity dispersion than the region as a whole, supporting a model of distributed massive-star formation rather than migration from the central clusters. We compare our stellar velocities to the Carina Nebula's molecular gas and find that Tr 14 shows a close kinematic association with the Northern Cloud. In contrast, Tr 16 has accelerated the Southern Cloud by 10-15 km s-1, possibly triggering further massive-star formation. The expansion of the surrounding H II region is not symmetric about the O-type stars in radial velocity space, indicating that the ionized gas is constrained by denser material on the far side.

Relationship of biomechanical factors to baseball pitching velocity: within pitcher variation.

Science.gov (United States)

Stodden, David F; Fleisig, Glenn S; McLean, Scott P; Andrews, James R

2005-02-01

To reach the level of elite, most baseball pitchers need to consistently produce high ball velocity but avoid high joint loads at the shoulder and elbow that may lead to injury. This study examined the relationship between fastball velocity and variations in throwing mechanics within 19 baseball pitchers who were analyzed via 3-D high-speed motion analysis. Inclusion in the study required each one to demonstrate a variation in velocity of at least 1.8 m/s (range 1.8-3.5 m/s) during 6 to 10 fastball pitch trials. Three mixed model analyses were performed to assess the independent effects of 7 kinetic, 11 temporal, and 12 kinematic parameters on pitched ball velocity. Results indicated that elbow flexion torque, shoulder proximal force, and elbow proximal force were the only three kinetic parameters significantly associated with increased ball velocity. Two temporal parameters (increased time to max shoulder horizontal adduction and decreased time to max shoulder internal rotation) and three kinematic parameters (decreased shoulder horizontal adduction at foot contact, decreased shoulder abduction during acceleration, and increased trunk tilt forward at release) were significantly related to increased ball velocity. These results point to variations in an individual's throwing mechanics that relate to pitched ball velocity, and also suggest that pitchers should focus on consistent mechanics to produce consistently high fastball velocities. In addition, pitchers should strengthen shoulder and elbow musculature that resist distraction as well as improve trunk strength and flexibility to maximize pitching velocity and help prevent injury.

A radial velocity survey of the Carina Nebula's O-type stars

Science.gov (United States)

Kiminki, Megan M.; Smith, Nathan

2018-06-01

We have obtained multi-epoch observations of 31 O-type stars in the Carina Nebula using the CHIRON spectrograph on the CTIO/SMARTS 1.5-m telescope. We measure their radial velocities to 1-2 km s-1 precision and present new or updated orbital solutions for the binary systems HD 92607, HD 93576, HDE 303312, and HDE 305536. We also compile radial velocities from the literature for 32 additional O-type and evolved massive stars in the region. The combined data set shows a mean heliocentric radial velocity of 0.6 km s-1. We calculate a velocity dispersion of ≤9.1 km s-1, consistent with an unbound, substructured OB association. The Tr 14 cluster shows a marginally significant 5 km s-1 radial velocity offset from its neighbour Tr 16, but there are otherwise no correlations between stellar position and velocity. The O-type stars in Cr 228 and the South Pillars region have a lower velocity dispersion than the region as a whole, supporting a model of distributed massive star formation rather than migration from the central clusters. We compare our stellar velocities to the Carina Nebula's molecular gas and find that Tr 14 shows a close kinematic association with the Northern Cloud. In contrast, Tr 16 has accelerated the Southern Cloud by 10-15 km s-1, possibly triggering further massive star formation. The expansion of the surrounding H II region is not symmetric about the O-type stars in radial velocity space, indicating that the ionized gas is constrained by denser material on the far side.

Velocity control of servo systems using an integral retarded algorithm.

Science.gov (United States)

Ramírez, Adrián; Garrido, Rubén; Mondié, Sabine

2015-09-01

This paper presents a design technique for the delay-based controller called Integral Retarded (IR), and its applications to velocity control of servo systems. Using spectral analysis, the technique yields a tuning strategy for the IR by assigning a triple real dominant root for the closed-loop system. This result ultimately guarantees a desired exponential decay rate σ(d) while achieving the IR tuning as explicit function of σ(d) and system parameters. The intentional introduction of delay allows using noisy velocity measurements without additional filtering. The structure of the controller is also able to avoid velocity measurements by using instead position information. The IR is compared to a classical PI, both tested in a laboratory prototype. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Shear-wave velocity compilation for Northridge strong-motion recording sites

Science.gov (United States)

Borcherdt, Roger D.; Fumal, Thomas E.

2002-01-01

Borehole and other geotechnical information collected at the strong-motion recording sites of the Northridge earthquake of January 17, 1994 provide an important new basis for the characterization of local site conditions. These geotechnical data, when combined with analysis of strong-motion recordings, provide an empirical basis to evaluate site coefficients used in current versions of US building codes. Shear-wave-velocity estimates to a depth of 30 meters are derived for 176 strong-motion recording sites. The estimates are based on borehole shear-velocity logs, physical property logs, correlations with physical properties and digital geologic maps. Surface-wave velocity measurements and standard penetration data are compiled as additional constraints. These data as compiled from a variety of databases are presented via GIS maps and corresponding tables to facilitate use by other investigators.

Europeanisation of private law and English law

OpenAIRE

Beale, Hugh

2003-01-01

To what extent is English Private Law being affected by the United Kingdom’s membership of the European Union? I think we can try to answer this at three levels: (i) The United Kingdom’s compliance with EU legislation; (ii) the influence of European ideas on English Private Law; (iii) the attitude in England towards greater harmonisation or possible unification of European Private Law

Law across nations

DEFF Research Database (Denmark)

of participants keen to work together to promote research and policy development in such a lively forum." - Professor Steve Saxby PhD, Cert Ed., MBCS Professor of IT Law and Public Policy, Solicitor, Deputy Head of School (Research), Faculty of Business and Law, University of Southampton, Editor...... not only the original themes of Legal, Security and Privacy Issues in IT Law and International Law and Trade but more recently two new conferences on International Public and Private Law. The papers in this volume then represent the contributions to all these fields and reflect the strong desire......-in-Chief, The Computer Law & Security Review - The International Journal of Technology Law and Practice (Elsevier), www.elsevier.com/locate/clsr, Editor, The Encyclopedia of Information Technology Law (Sweet & Maxwell), Director ILAWS - Institute for Law and the Web - School of Law, Southampton University, www...

A test of star formation laws in disk galaxies. II. Dependence on dynamical properties

International Nuclear Information System (INIS)

Suwannajak, Chutipong; Tan, Jonathan C.; Leroy, Adam K.

2014-01-01

We use the observed radial profiles of the mass surface densities of total, Σ g , and molecular, Σ H2 , gas, rotation velocity, and star formation rate (SFR) surface density, Σ sfr , of the molecular-rich (Σ H2 ≥ Σ HI /2) regions of 16 nearby disk galaxies to test several star formation (SF) laws: a 'Kennicutt-Schmidt (K-S)' law, Σ sfr =A g Σ g,2 1.5 ; a 'Constant Molecular' law, Σ sfr = A H2 Σ H2,2 ; the turbulence-regulated laws of Krumholz and McKee (KM05) and Krumholz, McKee, and Tumlinson (KMT09); a 'Gas-Ω' law, Σ sfr =B Ω Σ g Ω; and a shear-driven 'giant molecular cloud (GMC) Collision' law, Σ sfr = B CC Σ g Ω(1-0.7β), where β ≡ d ln v circ /d ln r. If allowed one free normalization parameter for each galaxy, these laws predict the SFR with rms errors of factors of 1.4-1.8. If a single normalization parameter is used by each law for the entire galaxy sample, then rms errors range from factors of 1.5-2.1. Although the Constant Molecular law gives the smallest rms errors, the improvement over the KMT, K-S, and GMC Collision laws is not especially significant, particularly given the different observational inputs that the laws utilize and the scope of included physics, which ranges from empirical relations to detailed treatment of interstellar medium processes. We next search for systematic variation of SF law parameters with local and global galactic dynamical properties of disk shear rate (related to β), rotation speed, and presence of a bar. We demonstrate with high significance that higher shear rates enhance SF efficiency per local orbital time. Such a trend is expected if GMC collisions play an important role in SF, while an opposite trend would be expected if the development of disk gravitational instabilities is the controlling physics.

Law Commissions – What is the essence of their law reform role?

Directory of Open Access Journals (Sweden)

Neil Faris

2014-10-01

Full Text Available Article by Neil Faris (Solicitor and a former Commissioner at the Northern Ireland Law Commission reflecting on the nature of law reform as carried out by law commissions. This is in the context of the author’s experience in the Northern Ireland Law Commission. The paper assesses the importance of independence in any law reform body and the particular impact which law commissioners may bring to the law reform process. The paper looks at the history of law reform in Northern Ireland leading to the establishment of the Commission with a brief overview of the work of the Commission. The conclusion is that there is a role for effective law reform driven by commissioner led independent law commissions. The author makes a strong case for the need for independent law commissions to promote high quality law reform. His article gives an idea about how law reform works in practice with law commissions providing one route for reforming the law.

Apparent Dependence of Rate- and State-Dependent Friction Parameters on Loading Velocity and Cumulative Displacement Inferred from Large-Scale Biaxial Friction Experiments

Science.gov (United States)

Urata, Yumi; Yamashita, Futoshi; Fukuyama, Eiichi; Noda, Hiroyuki; Mizoguchi, Kazuo

2017-06-01

We investigated the constitutive parameters in the rate- and state-dependent friction (RSF) law by conducting numerical simulations, using the friction data from large-scale biaxial rock friction experiments for Indian metagabbro. The sliding surface area was 1.5 m long and 0.5 m wide, slid for 400 s under a normal stress of 1.33 MPa at a loading velocity of either 0.1 or 1.0 mm/s. During the experiments, many stick-slips were observed and those features were as follows. (1) The friction drop and recurrence time of the stick-slip events increased with cumulative slip displacement in an experiment before which the gouges on the surface were removed, but they became almost constant throughout an experiment conducted after several experiments without gouge removal. (2) The friction drop was larger and the recurrence time was shorter in the experiments with faster loading velocity. We applied a one-degree-of-freedom spring-slider model with mass to estimate the RSF parameters by fitting the stick-slip intervals and slip-weakening curves measured based on spring force and acceleration of the specimens. We developed an efficient algorithm for the numerical time integration, and we conducted forward modeling for evolution parameters ( b) and the state-evolution distances (L_{{c}}), keeping the direct effect parameter ( a) constant. We then identified the confident range of b and L_{{c}} values. Comparison between the results of the experiments and our simulations suggests that both b and L_{{c}} increase as the cumulative slip displacement increases, and b increases and L_{{c}} decreases as the loading velocity increases. Conventional RSF laws could not explain the large-scale friction data, and more complex state evolution laws are needed.

RECENT CJEU CASE LAW TRENDS IN COMPETITION LAW

Directory of Open Access Journals (Sweden)

Virgilijus Valančius

2017-12-01

Full Text Available The objective of this article is to present the most significant recent case law of the Court of Justice of the European Union (CJEU related to the competition law. Firstly, focus is given to some recent CJEU case law in the antitrust area, i.e. the judgments dealing with the application of Articles 101 and 102 of the Treaty on the Functioning of the European Union (TFEU. A special attention is paid to the most recent CJEU case law analyzing the distinction between the object and effect of the prevention, restriction or distortion of competition. Secondly, some significant State aid cases are dealt with, i.e. the cases related to the application of Article 107 TFEU. Although the CJEU case law has not recently undergone major changes in the competition law field, the article reflects the main trends towards the current jurisprudence and what challenges may be expected in the future.

Velocity barrier-controlled of spin-valley polarized transport in monolayer WSe2 junction

Science.gov (United States)

Qiu, Xuejun; Lv, Qiang; Cao, Zhenzhou

2018-05-01

In this work, we have theoretically investigated the influence of velocity barrier on the spin-valley polarized transport in monolayer (ML) WSe2 junction with a large spin-orbit coupling (SOC). Both the spin-valley resolved transmission probabilities and conductance are strong dependent on the velocity barrier, as the velocity barrier decreases to 0.06, a spin-valley polarization of exceeding 90% is observed, which is distinct from the ML MoS2 owing to incommensurable SOC. In addition, the spin-valley polarization is further increased above 95% in a ML WSe2 superlattice, in particular, it's found many extraordinary velocity barrier-dependent transport gaps for multiple barrier due to evanescent tunneling. Our results may open an avenue for the velocity barrier-controlled high-efficiency spin and valley polarizations in ML WSe2-based electronic devices.

The growing interrelationship between nuclear law and environmental law

International Nuclear Information System (INIS)

Bourdon, Pierre

2015-01-01

With the recent United Nations Climate Change Conference (COP21) in Paris, a great deal of attention is being given to low-carbon energy technologies and policies that could help the world limit the global temperature increase to 2 deg. Celsius. Among these technologies, nuclear energy, which remains the largest source of low-carbon electricity in OECD countries and the second largest source of electricity at the global level after hydropower, can play a key role. The 2011 Fukushima Daiichi accident heightened public concern over the safety of nuclear energy in many countries. Because of the potentially far-reaching consequences of the use of nuclear energy on the environment in the case of an accident, it is commonly thought that nuclear law and environmental law are not entirely compatible or do not necessarily share the same objectives. Nuclear law may be defined as 'the body of special legal norms created to regulate the conduct of legal or natural persons engaged in activities related to fissionable materials, ionizing radiation and exposure to natural sources of radiation', while environmental law can be defined as 'the body of law that contains elements to control the human impact on the Earth and on public health'. These two areas of law were considered independently in the past, since the initial focus of nuclear law, which was developed before environmental law, was to protect people and property, without explicitly referring to the environment. However, the 1986 Chernobyl accident and increasing environmental concerns during that same decade led to a growing emphasis on environmental protection in the field of nuclear activities. On the one hand, nuclear law, as 'lex specialis', aims to ensure that nuclear activities are carried out in a manner that is safe for both the public and the environment. On the other hand, the expansion of the realm of environmental law has given rise to the application of environmentally focused

Renormalization, averaging, conservation laws and AdS (in)stability

International Nuclear Information System (INIS)

Craps, Ben; Evnin, Oleg; Vanhoof, Joris

2015-01-01

We continue our analytic investigations of non-linear spherically symmetric perturbations around the anti-de Sitter background in gravity-scalar field systems, and focus on conservation laws restricting the (perturbatively) slow drift of energy between the different normal modes due to non-linearities. We discover two conservation laws in addition to the energy conservation previously discussed in relation to AdS instability. A similar set of three conservation laws was previously noted for a self-interacting scalar field in a non-dynamical AdS background, and we highlight the similarities of this system to the fully dynamical case of gravitational instability. The nature of these conservation laws is best understood through an appeal to averaging methods which allow one to derive an effective Lagrangian or Hamiltonian description of the slow energy transfer between the normal modes. The conservation laws in question then follow from explicit symmetries of this averaged effective theory.

Effect of temperature and viscosity on swimming velocity of the copepod Acartia tonsa, brine shrimp Artemia salina and rotifer Brachionus plicatilis

DEFF Research Database (Denmark)

Larsen, Poul Scheel; Madsen, C.V.; Riisgard, H.U.

2008-01-01

Beating cilia are important organelles for swimming in many zooplanktonic aquatic organisms, including many invertebrate larvae, rotifers and ciliates, but other planktonic organisms, such as copepods and brine shrimps, use muscle-powered swimming appendages. In recent studies we found...... of swimming velocity for a 10 degrees C temperature reduction) that is found to be largest for the brine shrimp Artemia salina nauplius (37 %) and the rotifer Brachionus plicatilis (26%), but negligible for the copepod Acartia tonsa (4%). We suggest that experimental data on change in swimming velocity (V......) due to change in kinematic viscosity (v) be correlated in terms of a power law, V proportional to v(-m). The present data on swimming velocity of copepods, brine shrimps and rotifers show values of exponent m approximate to 1.5 to 3, with a trend of decreasing values for increasing size of species...

Challenges imposed by International Environmental Law to Classical International Law

Directory of Open Access Journals (Sweden)

Fabian Augusto Cárdenas Castañeda

2010-05-01

Full Text Available The emergence of international environmental law has produced important challenges to the very foundations of public international law. Traditional concepts such as state sovereignty, subjects of international law, and the early perspectives of national security are being transformed. The needs of the contemporary international society differ from the ones of the Wesphalian conception, situations which clearly explains the raise of alternative views for the understanding of the current dynamics of international law, where concepts like res communis, common concerns and simply “commons” take a privileged place in the study of international law. The foregoing has been strengthened by the international development of the so called erga ommnes obligations, label which is being used by international environmental law as the perfect explanation of its own existence. This academic article presents and studies the abovementioned concepts trying to compare what international law used to be before the emergence of international environmental law and what it is and what it should be in order to attend the developments and challenges imposed by the contemporary international society, particularly by international environmental law, a new fi eld of the corpus juris of public international law.

Underage drinking: does the minimum age drinking law offer enough protection?

Science.gov (United States)

Green, Rivka; Jason, Hannah; Ganz, Debora

2015-05-01

Underage drinking is a significant problem in the US. It is responsible for several thousand mortalities and fatalities each year, both among minors and other members of society. Additionally, underage alcohol consumption produces a severe economic burden in the US. Introduction to alcohol in youth poses serious long-term risks for adolescents, including occupational, educational, and psychosocial impairments, and increases the risk for developing alcohol abuse disorders in adulthood. In order to address and mitigate this problem, the US has set a minimum age drinking law of 21 in all 50 states, and has implemented several supplementary laws limiting the possession and consumption of alcohol. Though these laws have successfully reduced underage drinking, several additional strategies are noteworthy, including preventative and intervention efforts incorporating environmental, individual, communal, and parental factors. The following literature review describes these concepts as they relate to underage drinking laws in the US. Directions for future research, interventions, and ongoing challenges related to the minimum drinking age in the US are also discussed.

Sodium Velocity Maps on Mercury

Science.gov (United States)

Potter, A. E.; Killen, R. M.

2011-01-01

The objective of the current work was to measure two-dimensional maps of sodium velocities on the Mercury surface and examine the maps for evidence of sources or sinks of sodium on the surface. The McMath-Pierce Solar Telescope and the Stellar Spectrograph were used to measure Mercury spectra that were sampled at 7 milliAngstrom intervals. Observations were made each day during the period October 5-9, 2010. The dawn terminator was in view during that time. The velocity shift of the centroid of the Mercury emission line was measured relative to the solar sodium Fraunhofer line corrected for radial velocity of the Earth. The difference between the observed and calculated velocity shift was taken to be the velocity vector of the sodium relative to Earth. For each position of the spectrograph slit, a line of velocities across the planet was measured. Then, the spectrograph slit was stepped over the surface of Mercury at 1 arc second intervals. The position of Mercury was stabilized by an adaptive optics system. The collection of lines were assembled into an images of surface reflection, sodium emission intensities, and Earthward velocities over the surface of Mercury. The velocity map shows patches of higher velocity in the southern hemisphere, suggesting the existence of sodium sources there. The peak earthward velocity occurs in the equatorial region, and extends to the terminator. Since this was a dawn terminator, this might be an indication of dawn evaporation of sodium. Leblanc et al. (2008) have published a velocity map that is similar.

Interaction of ion clusters with fusion plasmas: Scaling laws

International Nuclear Information System (INIS)

Arista, N.R.; Bringa, E.M.

1997-01-01

The interaction between large ion clusters or very intense ion beams with fusion plasma is studied using the dielectric function formalism with appropriate quantum corrections. The contributions from individual and collective modes to the energy loss are calculated. The general properties of the interference effects are characterized in terms of the relevant parameters, and simple scaling laws are obtained. In particular, the conditions for a maximum enhancement in the energy deposition are derived. The study provides a unified view and a general formulation of collective effects in the energy loss for low and high velocities of the beam particles. copyright 1997 The American Physical Society

Computation of the velocity field and mass balance in the finite-element modeling of groundwater flow

International Nuclear Information System (INIS)

Yeh, G.T.

1980-01-01

Darcian velocity has been conventionally calculated in the finite-element modeling of groundwater flow by taking the derivatives of the computed pressure field. This results in discontinuities in the velocity field at nodal points and element boundaries. Discontinuities become enormous when the computed pressure field is far from a linear distribution. It is proposed in this paper that the finite element procedure that is used to simulate the pressure field or the moisture content field also be applied to Darcy's law with the derivatives of the computed pressure field as the load function. The problem of discontinuity is then eliminated, and the error of mass balance over the region of interest is much reduced. The reduction is from 23.8 to 2.2% by one numerical scheme and from 29.7 to -3.6% by another for a transient problem

Interface condition for the Darcy velocity at the water-oil flood front in the porous medium.

Science.gov (United States)

Peng, Xiaolong; Liu, Yong; Liang, Baosheng; Du, Zhimin

2017-01-01

Flood front is the jump interface where fluids distribute discontinuously, whose interface condition is the theoretical basis of a mathematical model of the multiphase flow in porous medium. The conventional interface condition at the jump interface is expressed as the continuous Darcy velocity and fluid pressure (named CVCM). Our study has inspected this conclusion. First, it is revealed that the principle of mass conservation has no direct relation to the velocity conservation, and the former is not the true foundation of the later, because the former only reflects the kinetic characteristic of the fluid particles at one position(the interface), but not the different two parts of fluid on the different side of the interface which required by the interface conditions. Then the reasonableness of CVCM is queried from the following three aspects:(1)Using Mukat's two phase seepage equation and the mathematical method of apagoge, we have disproved the continuity of each fluid velocity;(2)Since the analytical solution of the equation of Buckley-Leveret equations is acquirable, its velocity jumps at the flood front presents an appropriate example to disprove the CVCM;(3) The numerical simulation model gives impractical result that flood front would stop moving if CVCM were used to calculate the velocities at the interface between two gridcells. Subsequently, a new one, termed as Jump Velocity Condition Model (JVCM), is deduced from Muskat's two phase seepage equations and Darcy's law without taking account of the capillary force and compressibility of rocks and fluids. Finally, several cases are presented. And the comparisons of the velocity, pressure difference and the front position, which are given by JVCM, CVCM and SPU, have shown that the result of JVCM is the closest to the exact solution.

Interface condition for the Darcy velocity at the water-oil flood front in the porous medium.

Directory of Open Access Journals (Sweden)

Xiaolong Peng

Full Text Available Flood front is the jump interface where fluids distribute discontinuously, whose interface condition is the theoretical basis of a mathematical model of the multiphase flow in porous medium. The conventional interface condition at the jump interface is expressed as the continuous Darcy velocity and fluid pressure (named CVCM. Our study has inspected this conclusion. First, it is revealed that the principle of mass conservation has no direct relation to the velocity conservation, and the former is not the true foundation of the later, because the former only reflects the kinetic characteristic of the fluid particles at one position(the interface, but not the different two parts of fluid on the different side of the interface which required by the interface conditions. Then the reasonableness of CVCM is queried from the following three aspects:(1Using Mukat's two phase seepage equation and the mathematical method of apagoge, we have disproved the continuity of each fluid velocity;(2Since the analytical solution of the equation of Buckley-Leveret equations is acquirable, its velocity jumps at the flood front presents an appropriate example to disprove the CVCM;(3 The numerical simulation model gives impractical result that flood front would stop moving if CVCM were used to calculate the velocities at the interface between two gridcells. Subsequently, a new one, termed as Jump Velocity Condition Model (JVCM, is deduced from Muskat's two phase seepage equations and Darcy's law without taking account of the capillary force and compressibility of rocks and fluids. Finally, several cases are presented. And the comparisons of the velocity, pressure difference and the front position, which are given by JVCM, CVCM and SPU, have shown that the result of JVCM is the closest to the exact solution.

Medical marijuana laws, traffic fatalities, and alcohol consumption

OpenAIRE

Anderson, D. Mark; Rees, Daniel I.

2011-01-01

To date, 16 states have passed medical marijuana laws, yet very little is known about their effects. Using state-level data, we examine the relationship between medical marijuana laws and a variety of outcomes. Legalization of medical marijuana is associated with increased use of marijuana among adults, but not among minors. In addition, legalization is associated with a nearly 9 percent decrease in traffic fatalities, most likely to due to its impact on alcohol consumption. Our estimates pro...

Water velocity meter

Science.gov (United States)

Roberts, C. W.; Smith, D. L.

1970-01-01

Simple, inexpensive drag sphere velocity meter with a zero to 6 ft/sec range measures steady-state flow. When combined with appropriate data acquisition system, it is suited to applications where large numbers of simultaneous measurements are needed for current mapping or velocity profile determination.

Power laws and inverse motion modelling: application to turbulence measurements from satellite images

Directory of Open Access Journals (Sweden)

Pablo D. Mininni

2012-01-01

Full Text Available In the context of tackling the ill-posed inverse problem of motion estimation from image sequences, we propose to introduce prior knowledge on flow regularity given by turbulence statistical models. Prior regularity is formalised using turbulence power laws describing statistically self-similar structure of motion increments across scales. The motion estimation method minimises the error of an image observation model while constraining second-order structure function to behave as a power law within a prescribed range. Thanks to a Bayesian modelling framework, the motion estimation method is able to jointly infer the most likely power law directly from image data. The method is assessed on velocity fields of 2-D or quasi-2-D flows. Estimation accuracy is first evaluated on a synthetic image sequence of homogeneous and isotropic 2-D turbulence. Results obtained with the approach based on physics of fluids outperform state-of-the-art. Then, the method analyses atmospheric turbulence using a real meteorological image sequence. Selecting the most likely power law model enables the recovery of physical quantities, which are of major interest for turbulence atmospheric characterisation. In particular, from meteorological images we are able to estimate energy and enstrophy fluxes of turbulent cascades, which are in agreement with previous in situ measurements.

UNVEILING THE DETAILED DENSITY AND VELOCITY STRUCTURES OF THE PROTOSTELLAR CORE B335

Energy Technology Data Exchange (ETDEWEB)

Kurono, Yasutaka; Saito, Masao; Kamazaki, Takeshi; Morita, Koh-Ichiro; Kawabe, Ryohei, E-mail: yasutaka.kurono@nao.ac.jp [Chile Observatory, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)

2013-03-10

We present an observational study of the protostellar core B335 harboring a low-mass Class 0 source. The observations of the H{sup 13}CO{sup +}(J = 1-0) line emission were carried out using the Nobeyama 45 m telescope and Nobeyama Millimeter Array. Our combined image of the interferometer and single-dish data depicts detailed structures of the dense envelope within the core. We found that the core has a radial density profile of n(r){proportional_to}r {sup -p} and a reliable difference in the power-law indices between the outer and inner regions of the core: p Almost-Equal-To 2 for r {approx}> 4000 AU and p Almost-Equal-To 1.5 for r {approx}< 4000 AU. The dense core shows a slight overall velocity gradient of {approx}1.0 km s{sup -1} over the scale of 20, 000 AU across the outflow axis. We believe that this velocity gradient represents a solid-body-like rotation of the core. The dense envelope has a quite symmetrical velocity structure with a remarkable line broadening toward the core center, which is especially prominent in the position-velocity diagram across the outflow axis. The model calculations of position-velocity diagrams do a good job of reproducing observational results using the collapse model of an isothermal sphere in which the core has an inner free-fall region and an outer region conserving the conditions at the formation stage of a central stellar object. We derived a central stellar mass of {approx}0.1 M{sub Sun }, and suggest a small inward velocity, v{sub r{>=}r{sub i{sub n{sub f}}}}{approx}0 km s{sup -1} in the outer core at {approx}> 4000 AU. We concluded that our data can be well explained by gravitational collapse with a quasi-static initial condition, such as Shu's model, or by the isothermal collapse of a marginally critical Bonnor-Ebert sphere.

The molecular concept of law

Directory of Open Access Journals (Sweden)

Hendrik Gommer

2011-04-01

Full Text Available In his famous work The Concept of Law Hart asked himself the question 'what is law?' Hart makes a very strict distinction between rules and morals: morals are rooted in biology, rules source back to society. Hart's sociological truisms have proven to be untrue, because modern evolutionary biology is not about the survival of the individual (or even of a species but about the spreading of genes. This knowledge changes the fundamentals of Hart's theory and therefore his theory as a whole. In addition, my theory captures vital insights of Dworkin, legal realism, Posner and CLS, while at the same time forming a significant improvement upon them.In essence, the biological theory of law presented in this article is based on fractal patterns. Macroscale patterns recur in microscale patterns. The spreading of genes depends on important characteristics of genes: they are stable, they replicate, they need nutrients to replicate and they can cooperate. Superficially, genes, cells, organisms and groups may seem to act purposefully, but it is merely a pattern, with genes as generators, that brings structure to chaos. Human desires are in fact the needs of their genes. Thanks to language, morals can be put in words and become rules. To keep everyone working together, we need an ingenious device - like the law - to maintain that complex situations can continue to be judged on the basis of the simple principle of stability and reciprocity. To a degree, therefore, law itself can be derived from unconscious emotions and morals.

Tenancy Law Denmark

DEFF Research Database (Denmark)

Edlund, Hans Henrik

2003-01-01

Report on Danish Tenancy Law. Contribution to a research project co-financed by the Grotius Programme for Judicial Co-Operation in Civil Matters. http://www.iue.it/LAW/ResearchTeaching/EuropeanPrivateLaw/Projects.shtml......Report on Danish Tenancy Law. Contribution to a research project co-financed by the Grotius Programme for Judicial Co-Operation in Civil Matters. http://www.iue.it/LAW/ResearchTeaching/EuropeanPrivateLaw/Projects.shtml...

Influence of Norton's law parameters in the determination of stresses and deformation in materials undergo creep phenomenon

International Nuclear Information System (INIS)

Bevilacqua, L.; Freire, J.L.; Monteiro, E.; Miranda, P.E.V. de

1980-01-01

Experimental results obtained from creep essays for AISI 316 stainless-steel in different temperatures are presented. These results are rounded off by Norton's law for which parameters A e n are determined. It is studied how variations of Norton's law parameters affect the state of stresses and deformation in thin and thick pipes subjected, to internal pressure and constant temperature. It is concluded that for the cases studied the stresses are little affected by the variations of the parameter n and it is difficult too anticipate degrees of the accumulated deformation since the uncertainties or variations in A and n introduce serious errors in the calculation of the deformation velocity [pt

An Analysis of the Massachusetts Healthcare Law.

Science.gov (United States)

Stephens, James H; Ledlow, Gerald R; Sach, Michael V; Reagan, Julie K

2017-01-01

Healthcare in the United States has been one topic of the debates and discussion in the country for many years. The challenge for affordable, accessible, and quality healthcare for most Americans has been on the agenda of federal and state legislatures. There is probably no other state that has drawn as much individual attention regarding this challenge as the state of Massachusetts. While researching the topic for this article, it was discovered that financial and political perspectives on the success or failure of the healthcare model in Massachusetts vary depending on the aspect of the system being discussed. In this article the authors give a brief history and description of the Massachusetts Healthcare Law, explanation of how the law is financed, identification of the targeted populations in Massachusetts for which the law provides coverage, demonstration of the actual benefit coverage provided by the law, and review of the impact of the law on healthcare providers such as physicians and hospitals. In addition, there are explanations about the impact of the law on health insurance companies, discussion of changes in healthcare premiums, explanation of costs to the state for the new program, reviews of the impact on the health of the insured, and finally, projections on the changes that healthcare facilities will need to make to maintain fiscal viability as a result of this program.

An analytic solution of projectile motion with the quadratic resistance law using the homotopy analysis method

International Nuclear Information System (INIS)

Yabushita, Kazuki; Yamashita, Mariko; Tsuboi, Kazuhiro

2007-01-01

We consider the problem of two-dimensional projectile motion in which the resistance acting on an object moving in air is proportional to the square of the velocity of the object (quadratic resistance law). It is well known that the quadratic resistance law is valid in the range of the Reynolds number: 1 x 10 3 ∼ 2 x 10 5 (for instance, a sphere) for practical situations, such as throwing a ball. It has been considered that the equations of motion of this case are unsolvable for a general projectile angle, although some solutions have been obtained for a small projectile angle using perturbation techniques. To obtain a general analytic solution, we apply Liao's homotopy analysis method to this problem. The homotopy analysis method, which is different from a perturbation technique, can be applied to a problem which does not include small parameters. We apply the homotopy analysis method for not only governing differential equations, but also an algebraic equation of a velocity vector to extend the radius of convergence. Ultimately, we obtain the analytic solution to this problem and investigate the validation of the solution

Lhe law of diminishing elasticity of demand in Harrod’s trade cycle

OpenAIRE

Michaël Assous; Olivier Bruno; Muriel Dal-Pont

2014-01-01

In The Trade Cycle, Roy Harrod [1936a] propounded the Law of Diminishing Elasticity of Demand. The present paper tries to clarify the precise role Harrod assigned to this law in his The Trade Cycle Theory. We discuss the micro and macro foundations of the Law of Diminishing Elasticity of Demand and argue that it explains one of the main mechanisms that stabilize the economy during the trade cycle. In addition, we highlight how the Law of Diminishing Elasticity of Demand allowed Harrod to micr...

Study on Rayleigh Wave Inversion for Estimating Shear-wave Velocity Profile

Directory of Open Access Journals (Sweden)

T.A. Sanny

2003-05-01

Full Text Available Rayleigh wave or ground roll is a noise in seismic body waves. However, how to use this noise for soil characterization is very interesting since Rayleigh wave phase velocity is a function of compression-wave velocity, shear-wave velocity, density and layer thickness. In layered-medium Rayleigh wave velocity also depends on wavelength or frequency, and this phenomenon is called dispersion. Inversion procedure to get shear-wave velocity profile needs a priori information about the solution of the problem to limit the unknown parameters. The Lagrange multiplier method was used to solve the constrained optimization problems or well known as a smoothing parameter in inversion problems. The advantage of our inversion procedure is that it can guarantee the convergence of solution even though the field data is incomplete, insufficient, and inconsistent. The addition of smoothing parameter can reduce the time to converge. Beside numerical stability, the statistical stability is also involved in inversion procedure. In field experiment we extracted ground roll data from seismic refraction record. The dispersion curves had been constructed by applying f-k analysis and f-k dip filtering. The dispersion curves show the dependence of Rayleigh wave phase velocities in layered media to frequency. The synthetic models also demonstrate the stability and the speed of inversion procedure.

Isolated Bacterial Spores at High-velocity Survive Surface Impacts in Vacuum

Science.gov (United States)

Austin, Daniel; Barney, Brandon

We present experiments in which bacterial spores were found to survive being accelerated in vacuum to velocities in the range 30-120 m/s and impacted on a dense target. In these experiments, spores of Bacillus subtilis spores were charged using electrospray at atmospheric pressure, dried, and then introduced into high vacuum. Through choice of skimmers and beam tubes, different velocity ranges were achieved. An image-charge detector observed the charged spores, providing total charge and velocity. The spores then impacted a glass target within a collection vessel. After the experiment, the collection vessel contents were extracted and cultured. Several positive and negative controls were used, including the use of antibiotic-resistant spores and antibiotic-containing (rifampicin) agar for culturing. These impact velocities are of particular interest for possible transport of bacterial spores from Mars to Phobos, and may have implications for planetary protection in a Phobos sample return mission. In addition, bacteria may reach similar velocities during a spacecraft crash (e.g., within components, or from spacecraft to surface materials during impact, etc.), raising concerns about forward contamination. The velocities of interest to transport of life between planets (panspermia) are somewhat higher, but these results complement shock-based experiments and contribute to the general discussion of impact survivability of organisms.

Religious law versus secular law The example of the get refusal in Dutch, English and Israeli law

NARCIS (Netherlands)

Blois, M. de

2010-01-01

The tension between religious law and secular law in modern democracies is illustrated in this article by a discussion of the different approaches to the get (a bill of divorce) refusal (based on Jewish law) under Dutch, English and Israeli law. These legal orders share many characteristics, but

Field estimates of floc dynamics and settling velocities in a tidal creek with significant along-channel gradients in velocity and SPM

Science.gov (United States)

Schwarz, C.; Cox, T.; van Engeland, T.; van Oevelen, D.; van Belzen, J.; van de Koppel, J.; Soetaert, K.; Bouma, T. J.; Meire, P.; Temmerman, S.

2017-10-01

A short-term intensive measurement campaign focused on flow, turbulence, suspended particle concentration, floc dynamics and settling velocities were carried out in a brackish intertidal creek draining into the main channel of the Scheldt estuary. We compare in situ estimates of settling velocities between a laser diffraction (LISST) and an acoustic Doppler technique (ADV) at 20 and 40 cm above bottom (cmab). The temporal variation in settling velocity estimated were compared over one tidal cycle, with a maximum flood velocity of 0.46 m s-1, a maximum horizontal ebb velocity of 0.35 m s-1 and a maximum water depth at high water slack of 2.41 m. Results suggest that flocculation processes play an important role in controlling sediment transport processes in the measured intertidal creek. During high-water slack, particles flocculated to sizes up to 190 μm, whereas at maximum flood and maximum ebb tidal stage floc sizes only reached up to 55 μm and 71 μm respectively. These large differences indicate that flocculation processes are mainly governed by turbulence-induced shear rate. In this study, we specifically recognize the importance of along-channel gradients that places constraints on the application of the acoustic Doppler technique due to conflicts with the underlying assumptions. Along-channel gradients were assessed by additional measurements at a second location and scaling arguments which could be used as an indication whether the Reynolds-flux method is applicable. We further show the potential impact of along-channel advection of flocs out of equilibrium with local hydrodynamics influencing overall floc sizes.

Hyperbolic Conservation Laws and Related Analysis with Applications

CERN Document Server

Holden, Helge; Karlsen, Kenneth

2014-01-01

This book presents thirteen papers, representing the most significant advances and current trends in nonlinear hyperbolic conservation laws and related analysis with applications. Topics covered include a survey on multidimensional systems of conservation laws as well as novel results  on liquid crystals, conservation laws with discontinuous flux functions, and applications to sedimentation.  Also included are articles on recent advances in the Euler equations and the Navier-Stokes-Fourier-Poisson system, in addition to new results on collective phenomena described by the Cucker-Smale model.    The Workshop on Hyperbolic Conservation Laws and Related Analysis with Applications at the International Centre for Mathematical Sciences (Edinburgh, UK) held in Edinburgh, September 2011, produced this fine collection of original research and survey articles. Many leading mathematicians attended the event and submitted their contributions for this volume. It is addressed to researchers and graduate students inter...

Modeling of velocity field for vacuum induction melting process

Institute of Scientific and Technical Information of China (English)

CHEN Bo; JIANG Zhi-guo; LIU Kui; LI Yi-yi

2005-01-01

The numerical simulation for the recirculating flow of melting of an electromagnetically stirred alloy in a cylindrical induction furnace crucible was presented. Inductive currents and electromagnetic body forces in the alloy under three different solenoid frequencies and three different melting powers were calculated, and then the forces were adopted in the fluid flow equations to simulate the flow of the alloy and the behavior of the free surface. The relationship between the height of the electromagnetic stirring meniscus, melting power, and solenoid frequency was derived based on the law of mass conservation. The results show that the inductive currents and the electromagnetic forces vary with the frequency, melting power, and the physical properties of metal. The velocity and the height of the meniscus increase with the increase of the melting power and the decrease of the solenoid frequency.

Is Law science? | Roos | Potchefstroom Electronic Law Journal ...

African Journals Online (AJOL)

The question this contribution sets out to address is whether or not law can be regarded as a science. This notion is readily accepted by many, yet it is submitted that a proper theoretical justification for such an assumption is usually missing. The traditional primary sources of law, South African case law and legislation, ...

Exact solution for MHD flow of a generalized Oldroyd-B fluid with modified Darcy's law

International Nuclear Information System (INIS)

Khan, M.; Hayat, T.; Asghar, S.

2005-12-01

This paper deals with an exact solution for the magnetohydrodynamic (MHD) flow of a generalized Oldroyd-B fluid in a circular pipe. For the description of such a fluid, the fractional calculus approach has been used throughout the analysis. Based on modified Darcy's law for generalized Oldroyd-B fluid, the velocity field is calculated analytically. Several known solutions can be recovered as the limiting cases of our solution. (author)

Re-understanding the law-of-the-wall for wall-bounded turbulence based on in-depth investigation of DNS data

Science.gov (United States)

Cao, Bochao; Xu, Hongyi

2018-05-01

Based on direct numerical simulation (DNS) data of the straight ducts, namely square and rectangular annular ducts, detailed analyses were conducted for the mean streamwise velocity, relevant velocity scales, and turbulence statistics. It is concluded that turbulent boundary layers (TBL) should be broadly classified into three types (Type-A, -B, and -C) in terms of their distribution patterns of the time-averaged local wall-shear stress (τ _w ) or the mean local frictional velocity (u_τ ) . With reference to the Type-A TBL analysis by von Karman in developing the law-of-the-wall using the time-averaged local frictional velocity (u_τ ) as scale, the current study extended the approach to the Type-B TBL and obtained the analytical expressions for streamwise velocity in the inner-layer using ensemble-averaged frictional velocity (\\bar{{u}}_τ ) as scale. These analytical formulae were formed by introducing the general damping and enhancing functions. Further, the research applied a near-wall DNS-guided integration to the governing equations of Type-B TBL and quantitatively proved the correctness and accuracy of the inner-layer analytical expressions for this type.

Influence of lateral slab edge distance on plate velocity, trench velocity, and subduction partitioning

NARCIS (Netherlands)

Schellart, W. P.; Stegman, D. R.; Farrington, R. J.; Moresi, L.

2011-01-01

Subduction of oceanic lithosphere occurs through both trenchward subducting plate motion and trench retreat. We investigate how subducting plate velocity, trench velocity and the partitioning of these two velocity components vary for individual subduction zone segments as a function of proximity to

Water, law, science

Science.gov (United States)

Narasimhan, T. N.

2008-01-01

SummaryIn a world with water resources severely impacted by technology, science must actively contribute to water law. To this end, this paper is an earth scientist's attempt to comprehend essential elements of water law, and to examine their connections to science. Science and law share a common logical framework of starting with a priori prescribed tenets, and drawing consistent inferences. In science, observationally established physical laws constitute the tenets, while in law, they stem from social values. The foundations of modern water law in Europe and the New World were formulated nearly two thousand years ago by Roman jurists who were inspired by Greek philosophy of reason. Recognizing that vital natural elements such as water, air, and the sea were governed by immutable natural laws, they reasoned that these elements belonged to all humans, and therefore cannot be owned as private property. Legally, such public property was to be governed by jus gentium, the law of all people or the law of all nations. In contrast, jus civile or civil law governed private property. Remarkably, jus gentium continues to be relevant in our contemporary society in which science plays a pivotal role in exploiting vital resources common to all. This paper examines the historical roots of modern water law, follows their evolution through the centuries, and examines how the spirit of science inherent in jus gentium is profoundly influencing evolving water and environmental laws in Europe, the United States and elsewhere. In a technological world, scientific knowledge has to lie at the core of water law. Yet, science cannot formulate law. It is hoped that a philosophical understanding of the relationships between science and law will contribute to their constructively coming together in the service of society.

Analysis of self-similar solutions of multidimensional conservation laws

Energy Technology Data Exchange (ETDEWEB)

Keyfitz, Barbara Lee [The Ohio State Univ., Columbus, OH (United States)

2014-02-15

This project focused on analysis of multidimensional conservation laws, specifically on extensions to the study of self-siminar solutions, a project initiated by the PI. In addition, progress was made on an approach to studying conservation laws of very low regularity; in this research, the context was a novel problem in chromatography. Two graduate students in mathematics were supported during the grant period, and have almost completed their thesis research.

Dense velocity reconstruction from tomographic PTV with material derivatives

Science.gov (United States)

Schneiders, Jan F. G.; Scarano, Fulvio

2016-09-01

A method is proposed to reconstruct the instantaneous velocity field from time-resolved volumetric particle tracking velocimetry (PTV, e.g., 3D-PTV, tomographic PTV and Shake-the-Box), employing both the instantaneous velocity and the velocity material derivative of the sparse tracer particles. The constraint to the measured temporal derivative of the PTV particle tracks improves the consistency of the reconstructed velocity field. The method is christened as pouring time into space, as it leverages temporal information to increase the spatial resolution of volumetric PTV measurements. This approach becomes relevant in cases where the spatial resolution is limited by the seeding concentration. The method solves an optimization problem to find the vorticity and velocity fields that minimize a cost function, which includes next to instantaneous velocity, also the velocity material derivative. The velocity and its material derivative are related through the vorticity transport equation, and the cost function is minimized using the limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm. The procedure is assessed numerically with a simulated PTV experiment in a turbulent boundary layer from a direct numerical simulation (DNS). The experimental validation considers a tomographic particle image velocimetry (PIV) experiment in a similar turbulent boundary layer and the additional case of a jet flow. The proposed technique (`vortex-in-cell plus', VIC+) is compared to tomographic PIV analysis (3D iterative cross-correlation), PTV interpolation methods (linear and adaptive Gaussian windowing) and to vortex-in-cell (VIC) interpolation without the material derivative. A visible increase in resolved details in the turbulent structures is obtained with the VIC+ approach, both in numerical simulations and experiments. This results in a more accurate determination of the turbulent stresses distribution in turbulent boundary layer investigations. Data from a jet

Atomic energy law after the opt-out. Alive and fascinating. Report about the 14th German atomic energy law symposium 2012

International Nuclear Information System (INIS)

Leidinger, Tobias

2013-01-01

Atomic energy law remains a living, fascinating subject matter. Nearly 200 participants were convinced of this impression at the 14 th German Atomic Energy Law Symposium held in Berlin on November 19-20, 2012. Under the scientific chairmanship of Professor Dr. Martin Burgi, Ludwig Maximilian University of Munich, the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), after an interruption of 5 years, again organized a scientific conference about practice-related topics of atomic energy and radiation protection law. Atomic energy law once again proved to be a reference area for sophisticated issues of constitutional law and administrative law above and beyond its technical confines. The agenda of the 14 th German Atomic Energy Law Symposium featured a broad spectrum of topics ranging from backfitting of nuclear power plants to European atomic energy and radiation protection law, to challenges facing national legal systems in the execution of atomic energy law, to legal issues connected with decommissioning and waste management, and on to the topical subject of finding a repository site. The 14 th German Atomic Energy Law Symposium, on the whole, again demonstrated that an open discourse between science and practice is able to furnish important contributions to the implementation of laws in a balanced way rooted in practice. Especially the contributions dealing with the independence of public authorities and their organization, the doctrine of the reservation of functions of the executive branch, and planning by laws contain additional provisions able to influence the continued development of administrative law also above and beyond atomic energy law. The BMU also referred to a decision just heard from Brussels to the effect that a new European Safety Directive would be published as early as in 2013. As a consequence of the nuclear stress tests conducted EU-wide, the Directive is to lay down provisions about transparency

Electromagnetic velocity gauge: use of multiple gauges, time response, and flow perturbations

International Nuclear Information System (INIS)

Erickson, L.M.; Johnson, C.B.; Parker, N.L.; Vantine, H.C.; Weingart, R.C.; Lee, R.S.

1981-01-01

We have developed an in-situ electromagnetic velocity (EMV) gauge system for use in multiple-gauge studies of initiating and detonating explosives. We have also investigated the risetime of the gauge and the manner in which it perturbs a reactive flow. We report on the special precautions that are necessary in multiple gauge experiments to reduce lead spreading, simplify target fabrication problems and minimize cross talk through the conducting explosive. Agreement between measured stress records and calculations from multiple velocity gauge data give us confidence that our velocity gauges are recording properly. We have used laser velocity interferometry to measure the gauge risetime in polymethyl methacrylate (PMMA). To resolve the difference in the two methods, we have examined hydrodynamic and material rate effects. In addition, we considered the effects of shock tilt, electronic response and magntic diffusion on the gauge's response time

Additional integrals of the motion of classical Hamiltonian wave systems

International Nuclear Information System (INIS)

Shul'man, E.I.

1989-01-01

It is shown that a classical Hamiltonian wave system that possesses at least one additional integral of the motion with quadratic principal part has an infinite number of such integrals in the cases of both nondegenerate and degenerate dispersion laws. Conditions under which in a space of dimension d ≥ 2 a system with nondegenerate dispersion law is completely integratable and its Hamiltonian can be reduced to normal form are found. In the case of a degenerate dispersion law integrals are not sufficient for complete integrability

Comparative law as method and the method of comparative law

NARCIS (Netherlands)

Hage, J.C.; Adams, M.; Heirbaut, D.

2014-01-01

This article addresses both the justificatory role of comparative law within legal research (comparative law as method) and the method of comparative law itself. In this connection two questions will be answered: 1. Is comparative law a method, or a set of methods, for legal research? 2. Does

THE APLICATION OF ISLAMIC LAW IN INDONESIA: The Case Study in Aceh

Directory of Open Access Journals (Sweden)

Kamaruzzaman Bustamam-Ahmad

2007-06-01

Full Text Available This article provides an historical account of the implementation of Islamic law in Aceh and how the issue of Islamic law has been debated. The study will give more emphasis on the dynamics of the implementation of Islamic law, its historical development, typologies of Islamic law, leaders’ opinions regarding this issue, and the governments’ responses. This study argues that Islamic law in Aceh has been misinterpreted merely as h{udu>d law. In addition, it argues that the provincial government tends to put heavy emphasis on symbolic religious issues (such as the Islamic dress code and the usage of Arabic signs and letterheads, rather than the substance of Islamic law such as justice and prosperity for all. Finally, the study has made evident that implementing Islamic law is never a good method of attempting to resolve conflict. There is no need to establish Islamic law formally through the political process because, when politics enters in religious arena, it carries with it many interests.

International Treaties Tax Law in Brazilian Law

Directory of Open Access Journals (Sweden)

Milena Zampieri Sellmann

2016-06-01

Full Text Available International agreements are the primary source of obligations internationally, whi- ch generate reflections in national law. They have been extremely used in tax harvest because they avoid double taxation and reduce tax burden in international trade. They are formal sources of tax law, which the legislature is expressly recognized in Article 96 of the National Tax Code to set the “tax legislation” expression. Article 98 of the Code determines the supremacy of international tax agreements over national law. Against the odds, international tax agreements do not revoke or modify the national legislation, just limit the effectiveness of national law incompatible with them, with supra-legal hierarchy and infra-constitution. They are above national law, either after or before it is created, and are below the Federal Constitution, so agreements incompatible with it should not be approved by Congress and, if so, they will be subject to declaration of unconstitutionality by the Supreme Court. It is a reporting case the international agreement’s unconstitutio- nality after it is celebrated.

From the categorical imperative to the moral law

OpenAIRE

Vahl, Marianne

2008-01-01

This thesis is a critical survey of Christine Korsgaard’s arguments regarding the rational basis for moral obligations. I focus on her arguments taking us from the categorical imperative to the Moral Law. She makes a distinction that Kant does not; claiming that the categorical imperative is not the Moral Law. In order to equate rational agency with moral agency Korsgaard therefore needs some additional arguments. These arguments, I argue, are not convincing. My claim is that they do not succ...

Experimental evaluation of the MIT-SNL period-generated minimum time control laws for the rapid adjustment of reactor power

International Nuclear Information System (INIS)

Bernard, J.A.; Kwok, K.S.; Menadier, P.T.; Thome, F.V.; Wyant, F.J.

1987-01-01

The rapid adjustment of reactor neutronic power has recently been achieved by developing control laws that determine the actuator mechanism velocity necessary to produce a specified reactor period. Designated as the 'MIT-SNL Period-Generated Minimum Time Control Laws,' these relations are closed-form expressions of general applicability. In particular, if there is no limitation on the available rate of change of reactivity, these laws can be used to achieve virtually any desired power profile including time optimal ones. The innovative aspect of these laws is that the rate of change of reactivity rather than the reactivity itself is used as the control signal. For example, relative to a time-optimal response, these laws function by altering the rate of change of reactivity so that the instantaneous period is stepped from infinity to its minimum allowed value, held at that value until the desired power level is attained, and then stepped back to infinity. The response is time-optimal because the power adjustment is continuously made at the maximum allowed rate

CATEGORY OF CIRCUMVENTION OF THE LAW IN RUSSIAN CIVIL LAW

OpenAIRE

Kamyshanskiy V. P.

2014-01-01

This article examines the concept of "circumvention of the law" with respect to Treaty law. The author finds that the direct loan category "circumvention of the law" in Treaty law can be estimated ambiguously. The specified category which is fragmentary reflected in the active Civil codex indicates a regulatory gap

Soft law in public international law : a pragmatic or a principled choice?

NARCIS (Netherlands)

Brus, Marcel M.T.

2017-01-01

This paper discusses the role of soft law in international law, in particular in the field of sustainable development law. Soft law is often regarded as non-law. However this qualification increasingly does not match the realities of the development of international law in which many legally

Harmonization of Islamic Law in National Legal System A Comparative Study between Indonesian Law and Malaysian Law

Directory of Open Access Journals (Sweden)

Yeni Salma Barlinti

2011-01-01

Full Text Available This article compares Indonesian legal system and Malaysian legal system. The government legalized Islamic law in national legislateions, which are in effect for Muslim people. To facilitate dispute settlement, there is a religious court to solve Islamic dispute based on Islamic Law. The exsistence of Islamic law in Indonesia and Malaysia has similarity and differentiation. The similarities among others are: the Muslim-majority in both countries pushes the government to put Islamic law into force, Islamic law must be written into constitution or legislation. It is needed to have legal basis when performing Islamic law, the existence of religious court is very important in dispute settlement related to Islamic law. The Influence of western legal system is very strong in national legal system. Nevertheless, the western legal system differ substantially from Islamic legal system, and Islamic law was implemented limitedly based upon western legislation. It was limited to family law. While the differentiation are: the way of implementation of western legal system into national legal system and the form of legislation Indonesia has one legislation, which is in effect to all of Indonesian people. On the contrary, Malaysia has many enactments, which are different from one to another in each negeri.

Acoustic and streaming velocity components in a resonant waveguide at high acoustic levels.

Science.gov (United States)

Daru, Virginie; Reyt, Ida; Bailliet, Hélène; Weisman, Catherine; Baltean-Carlès, Diana

2017-01-01

Rayleigh streaming is a steady flow generated by the interaction between an acoustic wave and a solid wall, generally assumed to be second order in a Mach number expansion. Acoustic streaming is well known in the case of a stationary plane wave at low amplitude: it has a half-wavelength spatial periodicity and the maximum axial streaming velocity is a quadratic function of the acoustic velocity amplitude at antinode. For higher acoustic levels, additional streaming cells have been observed. Results of laser Doppler velocimetry measurements are here compared to direct numerical simulations. The evolution of axial and radial velocity components for both acoustic and streaming velocities is studied from low to high acoustic amplitudes. Two streaming flow regimes are pointed out, the axial streaming dependency on acoustics going from quadratic to linear. The evolution of streaming flow is different for outer cells and for inner cells. Also, the hypothesis of radial streaming velocity being of second order in a Mach number expansion, is not valid at high amplitudes. The change of regime occurs when the radial streaming velocity amplitude becomes larger than the radial acoustic velocity amplitude, high levels being therefore characterized by nonlinear interaction of the different velocity components.

Reaffirmation of additional (supplementary payments in company law of Republic of Serbia

Directory of Open Access Journals (Sweden)

Šogorov Stevan

2012-01-01

Full Text Available Subject matter of this article is development of legal regulation if additional payments in Serbia, from 1937 Commercial Code of Kingdom of Yugoslavia till nowadays. In introductory part author underlines legal nature, commercial function and importance of additional payments in private companies, with downfalls in regulation, court and busyness practice. 1988 Enterprise Act and 2004 Company Act has no regulations at all regarding additional payments. 1996 Enterprise Act and 2011 Company Act have provisions on additional payments, but with numerous weaknesses and open questions. Though critical analyses author underlines basic characteristics of additional payments included critical issues which may be expected during application of new legislature.

A note on poroacoustic traveling waves under Forchheimer's law

International Nuclear Information System (INIS)

Jordan, P.M.

2013-01-01

Acoustic traveling waves in a gas that saturates a rigid porous medium is investigated under the assumption that the drag experienced by the gas is modeled by Forchheimer's law. Exact traveling wave solutions (TWS)s, as well as approximate and asymptotic expressions, are obtained; decay rates are determined; and acceleration wave results are presented. In addition, special cases are considered, critical values of the wave variable and parameters are derived, and comparisons with predictions based on Darcy's law are performed. It is shown that, with respect to the Darcy case, most of the metrics that characterize such waveforms exhibit an increase in magnitude under Forchheimer's law

Numerical simulation of nanofluids based on power-law fluids with flow and heat transfer

Science.gov (United States)

Li, Lin; Jiang, Yongyue; Chen, Aixin

2017-04-01

In this paper, we investigate the heat transfer of nanofluids based on power-law fluids and movement of nanoparticles with the effect of thermophoresis in a rotating circular groove. The velocity of circular groove rotating is a constant and the temperature on the wall is kept to be zero all the time which is different from the temperature of nanofluids in the initial time. The effects of thermophoresis and Brownian diffusion are considered in temperature and concentration equations, and it is assumed that the thermal conductivity of nanofluids is a function of concentration of nanoparticles. Based on numerical results, it can be found that nanofluids improve the process of heat transfer than base fluids in a rotating circular groove. The enhancement of heat transfer increases as the power law index of base fluids decreases.

Finite-time consensus of second-order leader-following multi-agent systems without velocity measurements

International Nuclear Information System (INIS)

Zhang, Yanjiao; Yang, Ying

2013-01-01

This Letter investigates the finite-time consensus problems of second-order multi-agent systems in the presence of one and multiple leaders under a directed graph. Specifically, we propose two bounded control laws, which are independent of velocity information, to deal with the finite-time consensus tracking problem with one leader and the finite-time containment control problem with multiple leaders, respectively. With the aid of homogeneous theory, some sufficient conditions are established for the achievement of the finite-time tracking control problem of second-order multi-agent systems. Numerical examples are finally provided to illustrate the theoretical results.

Estimating Velocities of Glaciers Using Sentinel-1 SAR Imagery

Science.gov (United States)

Gens, R.; Arnoult, K., Jr.; Friedl, P.; Vijay, S.; Braun, M.; Meyer, F. J.; Gracheva, V.; Hogenson, K.

2017-12-01

In an international collaborative effort, software has been developed to estimate the velocities of glaciers by using Sentinel-1 Synthetic Aperture Radar (SAR) imagery. The technique, initially designed by the University of Erlangen-Nuremberg (FAU), has been previously used to quantify spatial and temporal variabilities in the velocities of surging glaciers in the Pakistan Karakoram. The software estimates surface velocities by first co-registering image pairs to sub-pixel precision and then by estimating local offsets based on cross-correlation. The Alaska Satellite Facility (ASF) at the University of Alaska Fairbanks (UAF) has modified the software to make it more robust and also capable of migration into the Amazon Cloud. Additionally, ASF has implemented a prototype that offers the glacier tracking processing flow as a subscription service as part of its Hybrid Pluggable Processing Pipeline (HyP3). Since the software is co-located with ASF's cloud-based Sentinel-1 archive, processing of large data volumes is now more efficient and cost effective. Velocity maps are estimated for Single Look Complex (SLC) SAR image pairs and a digital elevation model (DEM) of the local topography. A time series of these velocity maps then allows the long-term monitoring of these glaciers. Due to the all-weather capabilities and the dense coverage of Sentinel-1 data, the results are complementary to optically generated ones. Together with the products from the Global Land Ice Velocity Extraction project (GoLIVE) derived from Landsat 8 data, glacier speeds can be monitored more comprehensively. Examples from Sentinel-1 SAR-derived results are presented along with optical results for the same glaciers.

Global and local re-impact and velocity regime of ballistic ejecta of boulder craters on Ceres

Science.gov (United States)

Schulzeck, F.; Schröder, S. E.; Schmedemann, N.; Stephan, K.; Jaumann, R.; Raymond, C. A.; Russell, C. T.

2018-04-01

Imaging by the Dawn-spacecraft reveals that fresh craters on Ceres below 40 km often exhibit numerous boulders. We investigate how the fast rotating, low-gravity regime on Ceres influences their deposition. We analyze size-frequency distributions of ejecta blocks of twelve boulder craters. Global and local landing sites of boulder crater ejecta and boulder velocities are determined by the analytical calculation of elliptic particle trajectories on a rotating body. The cumulative distributions of boulder diameters follow steep-sloped power-laws. We do not find a correlation between boulder size and the distance of a boulder to its primary crater. Due to Ceres' low gravitational acceleration and fast rotation, ejecta of analyzed boulder craters (8-31 km) can be deposited across the entire surface of the dwarf planet. The particle trajectories are strongly influenced by the Coriolis effect as well as the impact geometry. Fast ejecta of high-latitude craters accumulate close to the pole of the opposite hemisphere. Fast ejecta of low-latitude craters wraps around the equator. Rotational effects are also relevant for the low-velocity regime. Boulders are ejected at velocities up to 71 m/s.

The peculiar velocities of rich clusters in the hot and cold dark matter scenarios

Science.gov (United States)

Rhee, George F.; West, Michael J.; Villumsen, Jens V.

1993-01-01

We present the results of a study of the peculiar velocities of rich clusters of galaxies. The peculiar motion of rich clusters in various cosmological scenarios is of interest for a number of reasons. Observationally, one can measure the peculiar motion of clusters to greater distances than galaxies because cluster peculiar motions can be determined to greater accuracy. One can also test the slope of distance indicator relations using clusters to see if galaxy properties vary with environment. We have used N-body simulations to measure the amplitude and rms cluster peculiar velocity as a function of bias parameter in the hot and cold dark matter scenarios. In addition to measuring the mean and rms peculiar velocity of clusters in the two models, we determined whether the peculiar velocity vector of a given cluster is well aligned with the gravity vector due to all the particles in the simulation and the gravity vector due to the particles present only in the clusters. We have investigated the peculiar velocities of rich clusters of galaxies in the cold dark matter and hot dark matter galaxy formation scenarios. We have derived peculiar velocities and associated errors for the scenarios using four values of the bias parameter ranging from b = 1 to b = 2.5. The growth of the mean peculiar velocity with scale factor has been determined and compared to that predicted by linear theory. In addition, we have compared the orientation of force and velocity in these simulations to see if a program such as that proposed by Bertschinger and Dekel (1989) for elliptical galaxy peculiar motions can be applied to clusters. The method they describe enables one to recover the density field from large scale redshift distance samples. The method makes it possible to do this when only radial velocities are known by assuming that the velocity field is curl free. Our analysis suggests that this program if applied to clusters is only realizable for models with a low value of the bias

RUSSIAN LAW SUBJECTS

Directory of Open Access Journals (Sweden)

D.N. Bakhrakh

2006-03-01

Full Text Available The question about the subjects of law branches is concerning the number of most important and difficult in law science. Its right decision influences on the subject of law regulation, precise definition of addressees of law norms, the volume of their rights and duties, the limits of action of norms of Main part of the branch, its principles. Scientific investigations, dedicated to law subjects system, promote the development of recommendations for the legislative and law applying activity; they are needed for scientific work organization and student training, for preparing qualified lawyers.

Obsolete Laws: Economic and Moral Aspects, Case Study-Composting Standards.

Science.gov (United States)

Vochozka, Marek; Maroušková, Anna; Šuleř, Petr

2017-12-01

From the early days of philosophy, ethics and justice, there is wide consensus that the constancy of the laws establishes the legal system. On the other hand, the rate at which we accumulate knowledge is gaining speed like never before. Due to the recently increased attention of academics to climate change and other environmental issues, a lot of new knowledge has been obtained about carbon management, its role in nature and mechanisms regarding the formation and degradation of organic matter. A multidisciplinary techno-economic assessment of current composting standards and laws that took into account the current state of knowledge about carbon management was carried out as a case study. Economic and environmental damage caused by outdated laws was revealed. In addition, it was found that the introduction of the best composts into the market is permitted, causing additional negative environmental as well as economic impacts.

China's Juvenile Delinquency Prevention Law: the law and the philosophy.

Science.gov (United States)

Lening Zhang; Jianhong Liu

2007-10-01

The present study introduces and discusses the Juvenile Delinquency Prevention Law of the People's Republic of China. The law was promulgated in the context of Chinese socioeconomic reforms and legal reforms in response to the rising delinquency since the early 1980s. The study explains the social and political background of the law with respect to the patterns of delinquency in China. The law has several main features that reflect the Chinese philosophical underpinnings of crime prevention and control, and the study discusses the connection between the law and the traditional Chinese philosophy and thinking. Finally, the study discusses the challenges to the enforcement of the law in Chinese society, which has lacked a legal tradition in its history.

Lindy's Law

Science.gov (United States)

Eliazar, Iddo

2017-11-01

Aging means that as things grow old their remaining expected lifetimes lessen. Either faster or slower, most of the things we encounter in our everyday lives age with time. However, there are things that do quite the opposite - they anti-age: as they grow old their remaining expected lifetimes increase rather than decrease. A quantitative formulation of anti-aging is given by the so-called ;Lindy's Law;. In this paper we explore Lindy's Law and its connections to Pareto's Law, to Zipf's Law, and to socioeconomic inequality.

The Newcomb-Benford law and nuclear half-lives

International Nuclear Information System (INIS)

Farkas, J.; Gyuerky, Gy.

2010-01-01

Compete text of publication follows. The satisfaction of the Newcomb-Benford law (a.k.a. Benford's first digit law) is a long standing issue in science, and has interesting mathematical and philosophical consequences. It was identified by Newcomb in 1881 and reinvented later by Benford in 1938. The law states that the distribution of the first digit of numbers taken from various sources like magazines, scientific publications, wealth statistics, etc. . . follows the law P d = lg (1 + 1/d) (d = 1, 2, ..., 9), where d is the given digit. It was reported recently that the satisfaction of the law was observed in nuclear decay half-life datasets. Based on this fact, it was implied that the law is helpful as a test for nuclear decay models, as well as it can be used to search for new physical phenomena (like self organized criticality) which can be responsible for the satisfaction of the law. The mathematical conundrum of the Newcomb-Benford law has been solved in 2008 for numbers coming from a data set with a given distribution. The 'Benford compliance theorem' uses the Fourier transform of the probability distribution function of the numbers to identify the characteristics of the distribution responsible for the satisfaction of the law. In our work we confirmed that the halflives of radioactive nuclei satisfy the law by using two standard techniques: direct plotting and the 'ones scaling test' method. We also showed that the distribution of the half-life values closely resembles a log-normal distribution stretching through about 54 orders of magnitude. By using the Fourier transform of the distribution function we showed that the numbers with such a distribution automatically satisfy the Newcomb-Benford law, due to the compliance theorem. Thus we concluded that the satisfaction of the law provides no additional clue on whether a nuclear model is valid or not, given it produces a similar distribution of halflives as observed.

Adaptive PID formation control of nonholonomic robots without leader's velocity information.

Science.gov (United States)

Shen, Dongbin; Sun, Weijie; Sun, Zhendong

2014-03-01

This paper proposes an adaptive proportional integral derivative (PID) algorithm to solve a formation control problem in the leader-follower framework where the leader robot's velocities are unknown for the follower robots. The main idea is first to design some proper ideal control law for the formation system to obtain a required performance, and then to propose the adaptive PID methodology to approach the ideal controller. As a result, the formation is achieved with much more enhanced robust formation performance. The stability of the closed-loop system is theoretically proved by Lyapunov method. Both numerical simulations and physical vehicle experiments are presented to verify the effectiveness of the proposed adaptive PID algorithm. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Water, law, science

Energy Technology Data Exchange (ETDEWEB)

Narasimhan, T.N.

2007-10-17

In a world with water resources severely impacted bytechnology, science must actively contribute to water law. To this end,this paper is an earth scientist s attempt to comprehend essentialelements of water law, and to examine their connections to science.Science and law share a common logical framework of starting with apriori prescribed tenets, and drawing consistent inferences. In science,observationally established physical laws constitute the tenets, while inlaw, they stem from social values. The foundations of modern water law inEurope and the New World were formulated nearly two thousand years ago byRoman jurists who were inspired by Greek philosophy of reason.Recognizing that vital natural elements such as water, air, and the seawere governed by immutable natural laws, they reasoned that theseelements belonged to all humans, and therefore cannot be owned as privateproperty. Legally, such public property was to be governed by jusgentium, the law of all people or the law of all nations. In contrast,jus civile or civil law governed private property. Remarkably, jusgentium continues to be relevant in our contemporary society in whichscience plays a pivotal role in exploiting vital resources common to all.This paper examines the historical roots of modern water law, followstheir evolution through the centuries, and examines how the spirit ofscience inherent in jus gentium is profoundly influencing evolving waterand environmental laws in Europe, the United States and elsewhere. In atechnological world, scientific knowledge has to lie at the core of waterlaw. Yet, science cannot formulate law. It is hoped that a philosophicalunderstanding of the relationships between science and law willcontribute to their constructively coming together in the service ofsociety.

Temperature effects on sinking velocity of different Emiliania huxleyi strains.

Science.gov (United States)

Rosas-Navarro, Anaid; Langer, Gerald; Ziveri, Patrizia

2018-01-01

The sinking properties of three strains of Emiliania huxleyi in response to temperature changes were examined. We used a recently proposed approach to calculate sinking velocities from coccosphere architecture, which has the advantage to be applicable not only to culture samples, but also to field samples including fossil material. Our data show that temperature in the sub-optimal range impacts sinking velocity of E. huxleyi. This response is widespread among strains isolated in different locations and moreover comparatively predictable, as indicated by the similar slopes of the linear regressions. Sinking velocity was positively correlated to temperature as well as individual cell PIC/POC over the sub-optimum to optimum temperature range in all strains. In the context of climate change our data point to an important influence of global warming on sinking velocities. It has recently been shown that seawater acidification has no effect on sinking velocity of a Mediterranean E. huxleyi strain, while nutrient limitation seems to have a small negative effect on sinking velocity. Given that warming, acidification, and lowered nutrient availability will occur simultaneously under climate change scenarios, the question is what the net effect of different influential factors will be. For example, will the effects of warming and nutrient limitation cancel? This question cannot be answered conclusively but analyses of field samples in addition to laboratory culture studies will improve predictions because in field samples multi-factor influences and even evolutionary changes are not excluded. As mentioned above, the approach of determining sinking rate followed here is applicable to field samples. Future studies could use it to analyse not only seasonal and geographic patterns but also changes in sinking velocity over geological time scales.

Recent publications on environmental law

International Nuclear Information System (INIS)

Lohse, S.

1991-01-01

The bibliography contains references to publications covering the following subject fields: General environmental law; environmental law in relation to constitutional law, administrative law, procedural law, revenue law, criminal law, private law, industrial law; law of regional development; nature conservation law; law on water protection; waste management law; law on protection against harmful effects on the environment; atomic energy law and radiation protection law; law of the power industry and the mining industry; laws and regulations on hazardous material and environmental hygiene. (orig.) [de

Competition And Antitrust Law In Ecuadorian Constitution

Directory of Open Access Journals (Sweden)

Marcelo Marín Sevilla

2013-01-01

Full Text Available This work allows us to establish the Economic Constitution and the Competition Law (C.L in the Constitution. Additionally, the paper analyzes whether the rules outlined in the C. L. and in doctrine are consistent and appropriate with the Constitution of Ecuador. The Competition and Antitrust Laws has rules for investigating and punishing the cartels, the abuses of power market (dominant position, the rules for merger control, the behaviors of Abuse of economic dependence, and unfair competition behaviors. Always the Antitrust Authority will analyze these behaviors in terms of welfare of both: the consumer and the market.

Peak negative myocardial velocity gradient in early diastole as a noninvasive indicator of left ventricular diastolic function: comparison with transmitral flow velocity indices.

Science.gov (United States)

Shimizu, Y; Uematsu, M; Shimizu, H; Nakamura, K; Yamagishi, M; Miyatake, K

1998-11-01

We sought to assess the clinical significance of peak negative myocardial velocity gradient (MVG) in early diastole as a noninvasive indicator of left ventricular (LV) diastolic function. Peak systolic MVG has been shown useful for the quantitative assessment of regional wall motion abnormalities, but limited data exist regarding the diastolic MVG as an indicator of LV diastolic function. Peak negative MVG was obtained from M-mode tissue Doppler imaging (TDI) in 43 subjects with or without impairment of systolic and diastolic performance: 12 normal subjects, 12 patients with hypertensive heart disease (HHD) with normal systolic performance and 19 patients with dilated cardiomyopathy (DCM), and was compared with standard Doppler transmitral flow velocity indices. In a subgroup of 30 patients, effects of preload increase on these indices were assessed by performing passive leg lifting. In an additional 11 patients with congestive heart failure at the initial examination, the measurements were repeated after 26+/-16 days of volume-reducing therapy. Peak negative MVG was significantly depressed both in HHD (-3.9+/-1.3/s, p indices failed to distinguish DCM from normal due to the pseudonormalization. Transmitral flow velocity indices were significantly altered (peak early/late diastolic filling velocity [E/A]=1.1+/-0.5 to 1.5+/-0.7, p indicator of LV diastolic function that is less affected by preload alterations than the transmitral flow velocity indices, and thereby could be used for the follow-up of patients with nonischemic LV dysfunction presenting congestive heart failure.

Seismic Imaging and Velocity Analysis Using a Pseudo Inverse to the Extended Born Approximation

KAUST Repository

Alali, Abdullah A.

2018-05-01

Prestack depth migration requires an accurate kinematic velocity model to image the subsurface correctly. Wave equation migration velocity analysis techniques aim to update the background velocity model by minimizing image residuals to achieve the correct model. The most commonly used technique is differential semblance optimization (DSO), which depends on applying an image extension and penalizing the energy in the non-physical extension. However, studies show that the conventional DSO gradient is contaminated with artifact noise and unwanted oscillations which might lead to local minima. To deal with this issue and improve the stability of DSO, recent studies proposed to use an inversion formula rather than migration to obtain the image. Migration is defined as the adjoint of Born modeling. Since the inversion is complicated and expensive, a pseudo inverse is used instead. A pseudo inverse formula has been developed recently for the horizontal space shift extended Born. This formula preserves the true amplitude and reduces the artifact noise even when an incorrect velocity is used. Although the theory for such an inverse is well developed, it has only been derived and tested on laterally homogeneous models. This is because the formula contains a derivative of the image with respect to a vertical extension evaluated at zero offset. Implementing the vertical extension is computationally expensive, which means this derivative needs to be computed without applying the additional extension. For laterally invariant models, the inverse is simplified and this derivative is eliminated. I implement the full asymptotic inverse to the extended Born to account for laterally heterogeneity. I compute the derivative of the image with respect to a vertical extension without performing any additional shift. This is accomplished by applying the derivative to the imaging condition and utilizing the chain rule. The fact that this derivative is evaluated at zero offset vertical

Velocity Building by Reflection Waveform Inversion without Cycle-skipping

KAUST Repository

Guo, Qiang

2017-05-26

Reflection waveform inversion (RWI) provides estimation of low wavenumber model components using reflections generated from a migration/demigration process. The resulting model tends to be a good initial model for FWI. In fact, the optimization images to combine the migration velocity analysis (MVA) objectives (given here by RWI) and the FWI ones. However, RWI may still encounter cycle-skipping at far offsets if the velocity model is highly inaccurate. Similar to MVA, RWI is devoted to focusing reflection data to its true image positions, yet because of the cycle skipping potential we tend to initially use only near offsets. To make the inversion procedure more robust, we introduce the extended image into our RWI. Extending the model perturbations (or image) allows us to better fit the data at larger offsets even with an inaccurate velocity. Thus, we implement a nested approach to optimize the velocity and extended image simultaneously using the objective function of RWI. We slowly reduce the extension, as the image becomes focused, to allow wavepath updates from far offsets to near as a natural progression from long wavelength updates to shorter ones. Applications on synthetic data demonstrate the effectiveness of our method without much additional cost to RWI.

Recent publications on environmental law

International Nuclear Information System (INIS)

Lohse, S.

1988-01-01

The bibliography contains 1235 references to publications covering the following subject fields: general environmental law; environmental law in relation to constitutional law, administrative law, procedural law, revenue law, criminal law, private law, industrial law; law of regional development; nature conservation law; law on water protection; waste management law; law on protection against harmful effects on the environment; atomic energy law and radiation protection law; law of the power industry and the mining industry; laws and regulations on hazardous material and environmental hygiene. (HP) [de

Recent publications on environmental law

International Nuclear Information System (INIS)

Lohse, S.

1989-01-01

The bibliography contains 1160 references to publications covering the following subject fields: General environmental law; environmental law in relation to constitutional law, administrative law, procedural law, revenue law, criminal law, private law, industrial law; law of regional development; nature conservation law; law on water protection; waste management law; law on protection against harmful effects on the environment; atomic energy law and radiation protection law; law of the power industry and the mining industry; laws and regulations on hazardous material and environmental hygiene. (orig./HP) [de

Investigating Coulomb's Law.

Science.gov (United States)

Noll, Ellis; Koehlinger, Mervin; Kowalski, Ludwik; Swackhamer, Gregg

1998-01-01

Describes the use of a computer-linked camera to demonstrate Coulomb's law. Suggests a way of reducing the difficulties in presenting Coulomb's law by teaching the inverse square law of gravity and the inverse square law of electricity in the same unit. (AIM)

Relevance of collagen piezoelectricity to "Wolff's Law": a critical review.

Science.gov (United States)

Ahn, Andrew C; Grodzinsky, Alan J

2009-09-01

According to "Wolff's Law", bone is deposited and reinforced at areas of greatest stress. From a clinical perspective, this "law" is supported by the strong association between bone density and physical activity. From a mechanistic standpoint, however, the law presents a challenge to scientists seeking to understand how osteocytes and osteoblasts sense the mechanical load. In the 1960s, collagen piezoelectricity was invoked as a potential mechanism by which osteocytes could detect areas of greater stress but piezoelectricity diminished in importance as more compelling mechanisms, such as streaming potential, were identified. In addition, accumulating evidence for the role of fluid-related shear stress in osteocyte's mechanosensory function has made piezoelectricity seemingly more obsolete in bone physiology. This review critically evaluates the role of collagen piezoelectricity (if any) in Wolff's Law--specifically, the evidence regarding its involvement in strain-generated potentials, existing alternate mechanisms, the present understanding of bone mechanosensation, and whether piezoelectricity serves an influential role within the context of this newly proposed mechanism. In addition to reviewing the literature, this review generates several hypotheses and proposes future research to fully address the relevance of piezoelectricity in bone physiology.

Recent Case Law

DEFF Research Database (Denmark)

Petz, Thomas; Sagaert, Vincent; Østergaard, Kim

2004-01-01

In this section authors from various European countries report the recent case law in their country on the field of private patrimonial law, that is decisions on the law of property, juridical acts, the law of obligations, contract law and prescription. The European Review of Private Law (ERPL......) started this section in 2003. The section aims to give our readers an overview of what is happening in the most recent European case law. We have asked the national reporters to report the juridical essence of the decisions given by the highest courts in their country. These national reports...... not relate the facts of the decision, nor the personal opinion of the reporter. One can find discussions on the most important decisions of European courts in ERPL’s case note section. The recent case law section gives overviews of decisions published in periods of four months. The period of January...

Basic conservation laws in the electromagnetic theory of cyclotron radiation: further analysis

International Nuclear Information System (INIS)

Lieu, R.; Leahy, D.A.

1984-01-01

The conflict of basic conservation laws in cyclotron radiation is considered in more general terms, taking into account relativistic effects of the electron. Also investigated are the effects due to the most important approximation in cyclotron theory, viz the omission of radiation back reaction. The conclusions are (i) the disagreement is of a magnitude considerably larger than any errors introduced by the approximation; (ii) the 'degree of conflict' attains its maximum in relativistic velocities, when the energy loss to radiation can approach the total energy of the electron. (author)

Wind laws for shockless initialization. [numerical forecasting model

Science.gov (United States)

Ghil, M.; Shkoller, B.

1976-01-01

A system of diagnostic equations for the velocity field, or wind laws, was derived for each of a number of models of large-scale atmospheric flow. The derivation in each case is mathematically exact and does not involve any physical assumptions not already present in the prognostic equations, such as nondivergence or vanishing of derivatives of the divergence. Therefore, initial states computed by solving these diagnostic equations should be compatible with the type of motion described by the prognostic equations of the model and should not generate initialization shocks when inserted into the model. Numerical solutions of the diagnostic system corresponding to a barotropic model are exhibited. Some problems concerning the possibility of implementing such a system in operational numerical weather prediction are discussed.

Laws for Access to and Management of Drinking Water in Tanzania

Directory of Open Access Journals (Sweden)

Leticia K. Nkonya

2006-06-01

Full Text Available Increasing human population, economic development and climatic changes in Sub-Saharan Africa (SSA have fuelled water scarcity, hence there is an urgent need for effective water management laws and institutions. Unfortunately, national and local governments rarely possess enough personnel or money to enforce their laws adequately. In SSA countries formal water management laws and institutions tend to ignore the customary laws and institutions. Additionally, local communities both filter and ignore formal laws and institutions and use their customary laws and institutions to manage their water resources. Despite their importance, there are only few empirical studies on customary laws and institutions for water management in SSA. This study attempts to fill this gap by analysing the impact of customary (informal laws on water management in Tanzania and show how they might be used to complement the statutory (formal laws for management of drinking water in rural Tanzania. The study will use both qualitative and quantitative methods to achieve this objective. This study found that customary laws and institutions are the most influential in water access, prevention of pollution and abuse of water. The awareness of the customary and water user group laws was also generally high, perhaps due to the participatory nature of those institutions. The study also found that statutory laws were important for water development issues but community awareness of these laws was low. These results suggest the need of using both customary and statutory laws since the two instruments complement each other.

Mass Flux and Terminal Velocities of Magnetically Driven Jets from Accretion Disks

Science.gov (United States)

Kudoh, Takahiro; Shibata, Kazunari

1995-10-01

In order to investigate astrophysical jets from accretion disks, we solve 1.5-dimensional steady MHD equations for a wide range of parameters, assuming the shape of poloidal magnetic field lines. We include a thermal effect to obtain the relation between the mass flux of the jet and the magnetic energy at the disk, although the jet is mainly accelerated by the magnetic force. It is found that the mass flux of the jets ( M dot ) is dependent on the magnetic energy at the disk surface, i.e., M dot ~ (rho Aa|Bp/B|)_{{slow}} ~ (rho Aa|Bp/Bphi|)_{{slow}} ~ Ealpha_{{mg}} [where rho is the density, a is the sound velocity, A is the cross section of the magnetic flux, B = (B2p + B2phi)^{1/2} , Bp and B phi are the poloidal and toroidal magnetic field strength, respectively, Emg is the magnetic energy in unit of the gravitational energy at the disk surface, and the suffix "slow" denotes the value at a slow point], when the magnetic energy is not too large. The parameter alpha increases from 0 to 0.5 with decreasing magnetic energy. Since the scaling law of Michel's minimum energy solution nearly holds in the magnetically driven flows, the dependence of the terminal velocity on the magnetic energy becomes weaker than had been expected, i.e., v_∞ ~ E^{(1-alpha)/3}_{{mg}} . It is shown that the terminal velocity of the jet is an order of Keplerian velocity at the footpoint of the jets for a wide range of values of Emg expected for accretion disks in star-forming regions and active galactic nuclei. We argue that the mass-loss rates observed in the star-forming regions would constrain the magnetic energies at the disk surfaces.

Improvement of the bubble rise velocity model in the pressurizer using ALMOD 3 computer code to calculate evaporation

International Nuclear Information System (INIS)

Madeira, A.A.

1985-01-01

It's studied the improvement for the calculation of bubble rise velocity, by adding two different ways to estimate this velocity, one of which more adequate to pressures normally found in the Reactor Cooling System. Additionally, a limitation in bubble rise velocity growth was imposed, to account for the actual behavior of bubble rise in two-phase mixtures. (Author) [pt

Performance Investigation of Air Velocity Effects on PV Modules under Controlled Conditions

Directory of Open Access Journals (Sweden)

Muzaffar Ali

2017-01-01

Full Text Available Junction temperature of PV modules is one of the key parameters on which the performance of PV modules depends. In the present work, an experimental investigation was carried out to analyze the effects of air velocity on the performance of two PV modules, that is, monocrystalline silicon and polycrystalline silicon under the controlled conditions of a wind tunnel in the presence of an artificial solar simulator. The parameters investigated include the surface temperature variation, power output, and efficiency of PV modules under varying air velocity from near zero (indoor lab. conditions to 15 m/s. Additionally, the results were also determined at two different module angular positions: at 0° angle, that is, parallel to air direction and at 10° angle with the direction of coming air to consider the effects of tilt angles. Afterwards, the thermal analysis of the modules was performed using Ansys-Fluent in which junction temperature and heat flux of modules were determined by applying appropriate boundary conditions, such as air velocity, heat flux, and solar radiation. Finally, the numerical results are compared with the experiment in terms of junction temperatures of modules and good agreement was found. Additionally, the results showed that the maximum module temperature drops by 17.2°C and the module efficiency and power output increased from 10 to 12% with increasing air velocity.

The critical ionization velocity

International Nuclear Information System (INIS)