Primary Quantities Research Articles

Real-Time Power Measurement Using the Maximal Overlap Discrete Wavelet-Packet Transform

This paper proposes the real-time estimation of the root-mean-square (rms) values, primary power quantities (active, total apparent, nonactive power, and power factor), and distortion power using the maximal overlap wavelet packet transform (MODWPT). The MODWPT provides a uniform frequency band and possesses the time-invariance property, which is ideal for the real-time power estimation. The performance of the proposed wavelet-based power measurement was assessed and compared to the IEEE Standard 1459-2010 in different case studies including stationary synthetic waveforms and power quality disturbances in experimental setup. The proposed method presented good results in the estimation of rms values and primary power quantities by using compact mother wavelets, whereas the estimation of distortion power was better with long mother wavelets.

IMPACT OF BARYONIC PHYSICS ON INTRINSIC ALIGNMENTS

ABSTRACT We explore the effects of specific assumptions in the subgrid models of star formation and stellar and active galactic nucleus feedback on intrinsic alignments of galaxies in cosmological simulations of the “MassiveBlack-II” family. Using smaller-volume simulations, we explore the parameter space of the subgrid star formation and feedback model and find remarkable robustness of the observable statistical measures to the details of subgrid physics. The one observational probe most sensitive to modeling details is the distribution of misalignment angles. We hypothesize that the amount of angular momentum carried away by the galactic wind is the primary physical quantity that controls the orientation of the stellar distribution. Our results are also consistent with a similar study by the EAGLE simulation team.

Steady heat conduction analyses using an interpolating element-free Galerkin scaled boundary method

Through use of the improved interpolating moving least-squares (IIMLS) shape functions in the circumferential direction of the scaled boundary method based on the Galerkin approach, an interpolating element-free Galerkin scaled boundary method (IEFG–SBM) is developed in this paper for analyzing steady heat conduction problems, which weakens the governing differential equations in the circumferential direction and seeks analytical solutions in the radial direction. The IIMLS method exhibits some advantages over the moving least-squares approximation and the interpolating moving least-squares method because its shape functions possess the delta function property and the involved weight function is nonsingular. In the IEFG–SBM, only a nodal data structure on the boundary is required and the primary unknown quantities are real solutions of nodal variables. Higher accuracy and faster convergence are obtained due to the increased smoothness and continuity of shape functions. Based on the IEFG–SBM, the steady heat conduction problems with thermal singularities and unbounded domains can be ideally modeled. Some numerical examples are presented to validate the availability and accuracy of the present method for steady heat conduction analysis.

A Bank Credit Model with Capital-Constrained Newsvendor Under Two Ordering Opportunities

AbstractThis paper proposes a financing system consisting of a bank under Mean-Variance criterion and a capital-constrained retailer, where the bank offers an unlimited credit to the retailer. The demand is assumed to be stochastic. The newsvendor is allowed to make an emergency order with a minimum reorder quantity threshold (RQT). It shows that under RQT, the newsvendor has different reorder strategies. The optimal primary order quantity and interest rate are derived, sequentially. Extension under perfectly competitive capital market is given. The mathematic model reveals that RQT and reorder price have significant effect on the optimal strategies.

The influence of solar system oscillation on the variability of the total solar irradiance

Total solar irradiance (TSI) is the primary quantity of energy that is provided to the Earth. The properties of the TSI variability are critical for understanding the cause of the irradiation variability and its expected influence on climate variations. A deterministic property of TSI variability can provide information about future irradiation variability and expected long-term climate variation, whereas a non-deterministic variability can only explain the past.This study of solar variability is based on an analysis of two TSI data series, one since 1700 A.D. and one since 1000 A.D.; a sunspot data series since 1610 A.D.; and a solar orbit data series from 1000 A.D. The study is based on a wavelet spectrum analysis. First, the TSI data series are transformed into a wavelet spectrum. Then, the wavelet spectrum is transformed into an autocorrelation spectrum to identify stationary, subharmonic and coincidence periods in the TSI variability.The results indicate that the TSI and sunspot data series have periodic cycles that are correlated with the oscillations of the solar position relative to the barycenter of the solar system, which is controlled by gravity force variations from the large planets Jupiter, Saturn, Uranus and Neptune. A possible explanation for solar activity variations is forced oscillations between the large planets and the solar dynamo.We find that a stationary component of the solar variability is controlled by the 12-year Jupiter period and the 84-year Uranus period with subharmonics. For TSI and sunspot variations, we find stationary periods related to the 84-year Uranus period. Deterministic models based on the stationary periods confirm the results through a close relation to known long solar minima since 1000 A.D. and suggest a modern maximum period from 1940 to 2015. The model computes a new Dalton-type sunspot minimum from approximately 2025 to 2050 and a new Dalton-type period TSI minimum from approximately 2040 to 2065.

Integrated demand and procurement portfolio management with spot market volatility and option contracts

The newsvendor problem aims to optimally choose a level of order quantity to respond to a known demand distribution with the objective of maximizing expected return. In practice, the decision maker is often challenged with more complex settings involving multiple decisions and uncertainties. For instance, firms may benefit from choosing the set of customer orders to satisfy. It may also be worthwhile for many firms to select a supply portfolio instead of relying on a single procurement mode. This paper provides novel optimization models and solution techniques that can help businesses to achieve the maximum performance from a given production system by optimally selecting customer demands, procurement quantity, spot market purchase and option contract usage. We specifically focus on the special case of normally distributed random variables, and provide an exact solution method. When the primary procurement quantity is not a decision variable, the problem becomes a version of a Stochastic Knapsack Problem. For this case, we present an efficient heuristic solution algorithm based on properties of an optimal solution and empirically show that it provides high-quality solutions. We also provide a broad numerical study to examine the sensitivity of integrated procurement and demand selection strategies to key problem parameters.

The mechanics of intersecting echelon veins and pressure solution seams in limestone

Many studies that describe the formation of echelon vein arrays relate the causative stresses implicitly to the deformation, reliant on simple shear kinematics, such that the vein-to-array angle and the array width are the primary physical quantities. In contrast, we identify twelve physical quantities to describe echelon veins in two dimensions, including coeval, vein-intersecting, pressure solution seams. A finite element method is used to reproduce vein shapes in linear elastic and elastic-perfectly plastic model limestone. Model vein geometries are designed using values within the range of geometries measured from echelon veins at Raplee Anticline and Comb Monocline, Utah.Four physical quantities are significant for describing echelon vein shapes: vein spacing, vein-array angle, limestone elastic stiffness, and closing of orthogonal pressure solution seams. Pressure solution seam closing influences the mechanical interaction between adjacent veins, and for a range of conditions, causes a nearly linear vein opening distribution (triangular shapes) and encourages straight vein propagation, both of which approximate field measurements. Model results show that small spacing of veins with seams and large vein-array angles promote straight vein traces in limestone with stiffness typical of laboratory measurements, given the physical geologic conditions inferred from the burial history of the limestone strata.

Instructive discussion of an effective block algorithm for baryon–baryon correlators

We describe an approach for the efficient calculation of a large number of four-point correlation functions for various baryon–baryon (BB) channels, which are the primary quantities for studying the nuclear and hyperonic nuclear forces from lattice quantum chromodynamics. Using the four-point correlation function of a proton-Λ system as a specific example, we discuss how an effective block algorithm significantly reduces the number of iterations. The effective block algorithm is applied to calculate 52 channels of the four-point correlation functions from nucleon–nucleon to Ξ–Ξ, in order to study the complete set of isospin symmetric BB interactions. The elapsed times measured for hybrid parallel computation on BlueGene/Q demonstrate that the performance of the present algorithm is reasonable for various combinations of the number of OpenMP threads and the number of MPI nodes. The numerical results are compared with the results obtained using the unified contraction algorithm for all computed sites of the 52 four-point correlators.

Nuclear Diagnostics at the National Ignition Facility, 2013-2015

The National Ignition Facility (NIF) relies on a suite of nuclear diagnostics to measure the neutronic output of experiments. Neutron time-of-flight (NTOF) and neutron activation diagnostics (NAD) provide performance metrics of absolute neutron yield and neutron spectral content: spectral width and non-thermal content, from which implosion physical quantities of temperature and scattering mass are inferred. Spatially-distributed flange- mounted NADs (FNAD) measure, with nearly identical systematic uncertainties, primary DT neutron emission to infer a whole-sky neutron field. An automated FNAD system is being developed. A magnetic recoil spectrometer (MRS) shares few systematics with comparable NTOF and NAD devices, and as such is deployed for independent measurement of the primary neutronic quantities. The gas-Cherenkov Gamma Reaction History (GRH) instrument records four energy channels of time-resolved gamma emission to measure nuclear bang time and burn width, as well as to infer carbon areal density in experiments utilizing plastic or diamond capsules. A neutron imaging system (NIS) takes two images of the neutron source, typically gated to create coregistered 13-15 MeV primary and 6-12 MeV downscattered images. The radiochemical analysis of gaseous samples (RAGS) instrument pumps target chamber gas to a chemical reaction and fractionation system configured with gamma counters, allowing measurement of radionuclides with half-lives as short as 8 seconds. Solid radiochemistry collectors (SRC) with backing NAD foils collect target debris, where activated materials from the target assembly are used as indicators of neutron spectrum content, and also serve as the primary diagnostic for nuclear forensic science experiments. Particle time-of-flight (PTOF) measures compression-bang time using DT- or DD-neutrons, as well as shock bang-time using D3He-protons for implosions with lower x-ray background. In concert, these diagnostics serve to measure the basic and advanced quantities required to understand NIF experimental results.

Canopy cover and anurans: nutrients are the most important predictor of growth and development

Bottom-up effects such as the availability of light and nutrients can have large impacts on primary producer quantity and quality, which is then translated into the growth and development of consumers. The use of “canopy cover” as a bottom-up predictive factor is a broad categorization, as canopy cover controls both the amount of light allowed into a pond and the nutrient load through leaf litter. To test how light and nutrients influence pond ecosystems, we manipulated inorganic nutrients and light in a 2 × 3 full-factorial, large-scale mesocosm experiment. Larval American Bullfrogs (Lithobates catesbeianus (Shaw, 1802)) were reared for 6 weeks at low densities and then assessed for development, growth, and survival at the end of the experiment. We also collected weekly samples of potential food resources (phytoplankton and periphyton) for the estimation of algal production and stoichiometric quality (carbon:nitrogen:phosphorus). Light had strong effects on food resource quality; however, resource quality did not significantly predict tadpole growth or development. Instead, nutrients seemed to be the most important factor as a stimulator of total algal primary production and some unknown pathway, which in turn affected tadpole development. Ours is the first study to investigate canopy cover using a comprehensive causal model, and our results suggest in regards to tadpole growth and development, canopy cover is important mainly as a source of nutrients to ponds.

Band structure computation of in-plane elastic waves in 2D phononic crystals by a meshfree local RBF collocation method

In this paper, the band structures of in-plane elastic waves in two-dimensional (2D) phononic crystals are calculated by using a meshfree local radial basis functions (RBF) collocation method. In order to improve the stability of the local RBF collocation method, special techniques suggested in our previous work for anti-plane waves are further improved and extended for calculating the primary field quantities and their normal derivatives required by the treatment of the boundary conditions in the local RBF collocation method for computing the band structures of the in-plane elastic waves in 2D phononic crystals. The developed meshfree local RBF collocation method for the band structure calculations of in-plane elastic waves propagating in 2D phononic crystals is validated by using the corresponding numerical results obtained with the finite element method (FEM). The band structures of different material combinations or acoustic impedance ratios, different filling fractions, various lattice forms and scatterer shapes are computed numerically to show the accuracy and the efficiency of the meshfree local RBF collocation method for computing the band structures of in-plane elastic waves in 2D phononic crystals.

A reciprocal theorem for boundary-driven channel flows

In a variety of physical situations, a bulk viscous flow is induced by a distribution of surface velocities, for example in diffusiophoresis (as a result of chemical gradients) and above carpets of cilia (as a result of biological activity). When such boundary-driven flows are used to pump fluids, the primary quantity of interest is the induced flow rate. In this letter we propose a method, based on the reciprocal theorem of Stokes flows, to compute the net flow rate for arbitrary flow distribution and periodic pump geometry using solely stress information from a dual Poiseuille-like problem. After deriving the general result we apply it to straight channels of triangular, elliptic and rectangular geometries and quantify the relationship between bulk motion and surface forcing.

Real-time comprehensive simulation of electric power systems for the task of overvoltages value determination

For a correct determining of the overvoltage limiters characteristics, as well as the optimal location of its installation is required to use reliable information about the primary electrical quantities, especially voltage level, in different operation modes of electric power systems (EPS). This problem is highly complex, due to the danger of the experiments in real EPS. Methods and tools for calculation and researches of quasi-stationary and switching overvoltages which are applied to solve this problem not always allow to obtain satisfactory results. The developed tools of comprehensive real-time simulation of electric power systems, providing adequate reproduction of processes associated with overvoltages in EPS, are presented in the article. Fragments of the researches of switching overvoltage in the electrical network of the real power system are given.

Quantum-mechanical diffraction theory of light from a small hole: Extinction-theorem approach

In a recent paper [Phys. Rev. A 90, 043830 (2014)] it was shown that the so-called aperture response tensor is the central concept in the microscopic quantum theory of light diffraction from a small hole in a flat screen. It was further shown that the quantum mechanical theory of diffraction only requires a preknowledge of the incident field plus the electronic properties of identical screens with and without a hole. Starting from the quantum mechanical expression for the linear conductivity tensor, we study the related causal conductivity tensor paying particular attention to diamagnetic electron dynamics. Using a nonlocal-potential separation assumption, we present a calculation of the diamagnetic causal surface conductivity for a jellium quantum-well screen using a two-dimensional Hartree-Fock model. In the diamagnetic case the difference between the light-unperturbed electron densities for screens with $({n}^{0})$ and without $({n}_{\ensuremath{\infty}}^{0})$ holes are the primary quantities for the diffraction theory. In a central part (Sec. IV) of this article we determine ${n}^{0}$ via a quantum-mechanical two-dimensional extinction-theorem approach related to elastic electron scattering from a hole with an electronic selvedge. For heuristic purposes we illustrate aspects of the extinction-theorem theory by applying the approach for an infinitely high potential barrier to the vacuum hole. Finally, we calculate and discuss the aperture response tensor in the small hole limit and in the zeroth-order Born approximation. Our final result for the aperture response tensor establishes the bridge to the anisotropic electric dipole polarizability tensor of the hole. It turns out that the effective optical aperture (hole) size relates closely to the extension of the relevant electronic wave functions scattered from the hole.

Local thermodynamical equilibrium and the $$\beta $$ β frame for a quantum relativistic fluid

We discuss the concept of local thermodynamical equilibrium in relativistic hydrodynamics in flat spacetime in a quantum statistical framework without an underlying kinetic description, suitable for strongly interacting fluids. We show that the appropriate definition of local equilibrium naturally leads to the introduction of a relativistic hydrodynamical frame in which the four-velocity vector is the one of a relativistic thermometer at equilibrium with the fluid, parallel to the inverse temperature four-vector $$\beta $$ , which then becomes a primary quantity. We show that this frame is the most appropriate for the expansion of the stress-energy tensor from local thermodynamical equilibrium and that therein the local laws of thermodynamics take on their simplest form. We discuss the difference between the $$\beta $$ frame and Landau frame and present an instance where they differ.

Flow effects due to valve and piston motion in an internal combustion engine exhaust port

Performance optimization regarding e.g. exhaust valve strategies in an internal combustion engine is often performed based on one-dimensional simulation investigation. Commonly, a discharge coefficient is used to describe the flow behavior in complex geometries, such as the exhaust port. This discharge coefficient for an exhaust port is obtained by laboratory experiments at fixed valve lifts, room temperatures, and low total pressure drops. The present study investigates the consequences of the valve and piston motion onto the energy losses and the discharge coefficient. Therefore, Large Eddy Simulations are performed in a realistic internal combustion geometry using three different modeling strategies, i.e. fixed valve lift and fixed piston, moving piston and fixed valve lift, and moving piston and moving valve, to estimate the energy losses. The differences in the flow field development with the different modeling approaches is delineated and the dynamic effects onto the primary quantities, e.g. discharge coefficient, are quantified. Considering the motion of piston and valves leads to negative total pressure losses during the exhaust cycle, which cannot be observed at fixed valve lifts. Additionally, the induced flow structures develop differently when valve motion is taken into consideration, which leads to a significant disparity of mass flow rates evolving through the two individual valve ports. However, accounting for piston motion and limited valve motion, leads to a minor discharge coefficient alteration of about one to two percent.

The role of time and frequency metrology inside the new definitions of SI quantities

There is an on-going discussion, initiated in 2011, which proposes several changes to the official definitions of the base units of the International System of Units (SI). This will also entail changes in the relationships between the primary quantities of SI and some universal constants. One result of this process points in the direction of giving greater importance and centrality to unit of time (s), increasing the practical importance of the realization of the quantities frequency and time. So, it is strongly recommended that the metrological maintenance of these quantities, in Brazil, be done in the Campus of INMETRO.

The particle velocity, speed equation and universal asymptotics for the efficient modelling of hydraulic fractures

The theoretical rationale of the hydraulic fracture (HF) problem is revisited. It implies that the particle velocity is the primary physical quantity, the use of which has significant analytical and computational advantages over the conventional use of flux. The fundamental significance of the speed equation (SE) for the proper tracing of fracture propagation is emphasized. It appears that when the lag between the fracture contour and the fluid front is neglected, the asymptotic form of the continuity equation (CE) agrees identically with the SE for non-singular or weakly singular leak-off. For strongly singular leak-off of the Carter’ type, the asymptotic form of the CE yields a generalized speed equation. We show that for zero lag, the system, comprised of the asymptotic CE, the elasticity equation and fracture condition, defines the universal asymptotic solution (universal asymptotic umbrella) of the HF problem. Its remarkable property is that it depends solely on the local propagation speed. On one hand, this fact makes the HF problem ill-posed when neglecting the lag and trying to solve it as a boundary value problem for a fixed position of the front. On the other hand, when properly employed, it considerably facilitates analytical and numerical solutions. Specifically, one may use either highly efficient ɛ-regularization or inclusion of the SE as an additional equation with the front coordinate as an additional unknown what provides a well-posed dynamic problem. We show that the latter may be efficiently solved by a variety of methods including explicit and implicit level set methods. In view of the significance of the universal asymptotic umbrella, we derive a simple almost monomial universal solution applicable for any regime of HF propagation.

Microwave Resonant Methods for Bone Replacement Biomaterials Testing

The purpose of this work was to find out to what extent the knowledge of dependence of impedance on the crack depth observed by means of microwave frequencies can be used as noninvasive techniques for biocompatible materials which are used in bone replacement. Primary quantity usable for this assessment was the reflection coefficient obtained from the standing wave ratio measurement. The measured and calculated results are given in the graphic form and are compared each other in common graphs which provide a good overview about basic quantities and simultaneously give an initiative for orientation on practical applications in the process of defect presence finding in materials used in bone replacement.

Switching Between the NVT and NpT Ensembles Using the Reweighting and Reconstruction Scheme

Abstract Recently, we have developed several techniques in order to accelerate Monte Carlo (MC) molec- ular simulations. For that purpose, two strategies were followed. In the first, new algorithms were proposed as a set of early rejection schemes performing faster than the conventional al- gorithm while preserving the accuracy of the method. On the other hand, a reweighting and reconstruction scheme was introduced that is capable of retrieving primary quantities and sec- ond derivative properties at several thermodynamic conditions from a single MC Markov chain. The latter scheme, was first developed to extrapolate quantities in NV T ensemble for struc- tureless Lennard-Jones particles. However, it is evident that for most real life applications the NpT ensemble is more convenient, as pressure and temperature are usually known. Therefore, in this paper we present an extension to the reweighting and reconstruction method to solve NpT problems utilizing the same Markov chains generated by the NV T ensemble simulations. Eventually, the new approach allows elegant switching between the two ensembles for several quantities at a wide range of neighboring thermodynamic conditions.