Parameters Rc Research Articles

Surface morphology of blended molding pellets made of desert caragana and maize stover

The surface morphology of biomass pellets can provide data for the contact mechanics fractal model between the molding pellet and hole in biomass molding machines and for predicting wear of the molding hole. In this study, desert caragana (Caragana korshinskii) was mixed with residue from maize production, crushed, and compressed into pellets, which were used to collect data on their circumferential surface roughness profile, density, diameter, and hardness. The results showed that frictional wear occurs during contact between the forming hole and the molding particles, increasing the diameter d0 of the forming hole and the diameter d of the molding particles. The density ρ and hardness HD of the molded pellets decreased as their diameter d increased, and the ρ and HD of caragana were higher in autumn than in summer. The values of the roughness parameters Ra, Rc and Rz of the molded particles increased with their diameter d. The maximum material rate Mr2 value of the roughness’s central profile remained at 86% with the increase of diameter d. Molded particles had surface roughness kurtosis Rku>3 and roughness skew Rsk<0 with the increase of diameter d. The surface of molded particles was spiky and negatively skewed, and with a low number of spikes.

Proton Exchange Membrane Fuel Cell Parameter Extraction Using a Supply–Demand-Based Optimization Algorithm

For proton exchange membrane fuel cells (PEMFCs), the parameter extraction issue is among the most widely studied problems in the field of energy storage systems, since the precise identification of such parameters plays an important role in increasing the PEMFC performance and life span. The optimization process is intended to adjust the performance of PEMFCs by appraising the optimal parameters that produce a good estimation of the current–voltage (I–V) curve. In order to build an accurate equivalent circuit model for PEMFCs, a reliable and effective parameter extraction algorithm, termed a supply–demand-based optimization (SDO) algorithm, is proposed in this paper. Nine parameters (ξ1, ξ2, ξ3, ξ4, Rc, β, λ, l, and Jmax) are evaluated, to minimize the sum squared deviation (SSE) between the experimental and simulated I–V curves. To validate the feasibility and effectiveness of the SDO algorithm, four sets of experimental data with diverse characteristics and two well-known PEMFC stacks (BSC500W and 500W Horizon) are employed. Comparison of the simulated and experimental results clearly demonstrates the superiority/competitiveness of the SDO algorithm over five well-established parameter extraction algorithms, i.e., the whale optimization algorithm (WOA), grey wolf optimization (GWO), Harris hawks optimization (HHO), and genetic algorithm (GA). Several evaluation criteria, including best SSE, worst SSE, mean SSE, and standard deviation, show that the SDO algorithm has merits in terms of PEMFC modeling.

The Optical Aspect of Errors in Measurements of Surface Asperities Using the Optical Profilometry Method

The paper presents the impact of lighting type and direction on measurements of surface asperities using focus-variation microscopy. Particular attention was paid to the direction of lighting when using a light ring. It was pointed out that the lighting direction directly affects the values of the parameters Rt, Rz, and Rc. The article also presents the impact of a light polarizer on the surface topography parameters. It has been shown that the positioning of a sample with a regular and directed structure relative to the optical axis of the light polarizer affects the accuracy of mapping surface asperities. The largest differences were observed for Rz and Rt parameters. A method of using an external polarizer mounted on a focus variation microscope lens was also presented. Keywords: surface topography,

Theoretical calculation method for crack resistance of jacketed RC columns

Theoretical method of crack width calculation in jacketed reinforced concrete columns is described and validated in this paper. The total number of tested columns was 12. The initial load applied to the column before strengthening was the main variable parameter in this test. Columns were strengthened by reinforced concrete jacketing after loading. Two RC columns were tested without strengthening to serve as reference samples. Two RC columns were strengthened with RC jacketing without any initial loading to determine maximum strengthening effect. Loading was applied in steps. This study is the calculation of the crack resistance parameters RC columns, strengthened by RC jacketing under the influence of various initial loads. Crack width and pattern were checked after each step. The maximum allowed crack width for test samples was adopted as wmax = 0.3 mm. The rest eight samples were preliminarily loaded to 0.3; 0.5; 0.7 and 0.9 of reference columns bearing capacity, strengthened and tested to failure. The results of theoretical calculation deviate from test results by 13.6…27.9%.

Entanglement measures of W-state in noninertial frames

In this work we present the entanglement measures of a tripartite W-State entangled system in noninertial frame through the coordinate transformation between Minkowski and Rindler. Two cases are considered, i.e., when one qubit goes in a uniform acceleration a and the others remain stationary and when two qubits undergo in a uniform acceleration and while the other is stationary. The analytical negativities for one-tangle, two-tangle and π-tangle in total are not written out explicitly except for some special cases due to complicated expressions, but we illustrate them in graphics and study their dependencies on the acceleration parameters rb and rc. We find that the negativities of the one-tangle, two-tangle and π-tangle decrease with the acceleration parameters except for the constant NAB=NBA. The negativity NCI(AB) and the πCI decrease faster than NA(BCI) and πA(πB). The negativities NACI (NB(ACI))and NBICI decrease faster than those NAB and NABI, respectively. It is interesting to see there exist turning points for the negativity NA(BICI) at the coordinate position (rb,rc) with rb=rc, which implies that the NA(BICI) has minimum value when Bob and Charlie are on the same position and the degree of the entanglement of the subsystem ρA(BICI) becomes smallest. The von Neumann entropy of tripartite system densities ρABCI and ρABICI are obtained analytically. We notice that they all increase with the acceleration parameters rb and rc.

Effects of nanoparticles (Cu, TiO[formula omitted], Al[formula omitted]O[formula omitted]) on unsteady blood flow through a curved overlapping stenosed channel

In this letter, we have explored the effects of nanoparticles on unsteady pulsatile blood flow through a curved overlapping stenosed channel. The governing differential equations are derived for the given physical problem and this contains momentum and energy equations along with suitable boundary conditions. An explicit finite difference technique has been used to calculate the numerical results of the given differential equations. The numerical results for different values of curved parameter (Rc), nanoparticles (Cu, TiO2, Al2O3) and Grashof numbers (Gr) are calculated in order to analyze the effects of these parameters on blood flow pattern. A notable deviation in the results of blood flow pattern has been observed with the comparison of pure blood with nano-fluids. It is further noted that the curved parameter (Rc) of a channel has a great influence on velocity profile, flow rate and impedance/resistance to flow. It is also extracted from the velocity profiles that the shape of the velocity curves reduces to symmetric pattern for the higher values of the curved parameters (Rc). Similarly, the magnitude of temperature profiles is constricted due to the insertion of nanoparticles within blood. Moreover, streamlines are also calculated in order to analyze the effects of nanoparticles inside the circulating regions of the flow field.

Internal surface roughness of plastic pipes for irrigation

ABSTRACT Assuming that a roughness meter can be successfully employed to measure the roughness on the internal surface of irrigation pipes, this research had the purpose of defining parameters and procedures required to represent the internal surface roughness of plastic pipes used in irrigation. In 2013, the roughness parameter Ra, traditional for the representation of surface irregularities in most situations, and the parameters Rc, Rq, and Ry were estimated based on 350 samples of polyvinyl chloride (PVC) and low-density polyethylene (LDPE) pipes. Pressure losses were determined from experiments carried out in laboratory. Estimations of pressure loss varied significantly according to the roughness parameters (Ra, Rc, Rq, and Ry) and the corresponding pipe diameter. Therefore, specific values of roughness for each pipe diameter improves accuracy in pressure losses estimation. The average values of internal surface roughness were 3.334 and 8.116 μm for PVC and LDPE pipes, respectively.

Contributions to Constructive Treatment of SIS-Type Models II: Nonstandard Volterra Difference Equation

This work is divided in two parts. In the first part, we construct and investigate the reliability of various NSFD schemes for diffusion and space-independent models. We consider two new NSFD schemes for the SIS-ODE model, which faithfully replicate the property of the continuous model of having the value R_{0}=1 of the basic reproduction parameter as a forward bifurcation: the disease-free equilibrium (DFE) is globally asymptotically stable (GAS) when R_{0} 1, and there appears a unique locally asymptotically stable (LAS) endemic equilibrium (EE) in this case.The schemes are further used to derive NSFD schemes that are dynamically consistent with the positivity and boundedness properties of the SIS-diffusion model. In the second part, the contact rate is a function of the infective population and we incorporate a distributed infective period. The resulting SIS-model is a Volterra integral equation of the second kind. The qualitative analysis is now based on two threshold parameters Rc_{0} Rm_{0} with the DFE being unstable when R_{0} > 1; for Rc_{0} < R_{0} < 1; the DFE is LAS and co-exists with at least one LAS endemic equilibrium. We design a NSFD scheme that preserves positivity and boundedness of the solution as well as the above-stated stability properties of equilibria. Numerical simulations that support the theory are provided.

Contributions to Constructive Treatment of SIS-Type Models I: Nonstandard Schemes for Diffusion and Non-Diffusion Models

This work is divided in two parts. In the first part, we construct and investigate the reliability of various NSFD schemes for diffusion and space-independent models. We consider two new NSFD schemes for the SIS-ODE model, which faithfully replicate the property of the continuous model of having the value R_{0}=1 of the basic reproduction parameter as a forward bifurcation: the disease-free equilibrium (DFE) is globally asymptotically stable (GAS) when R_{0} 1, and there appears a unique locally asymptotically stable (LAS) endemic equilibrium (EE) in this case.The schemes are further used to derive NSFD schemes that are dynamically consistent with the positivity and boundedness properties of the SIS-diffusion model. In the second part, the contact rate is a function of the infective population and we incorporate a distributed infective period. The resulting SIS-model is a Volterra integral equation of the second kind. The qualitative analysis is now based on two threshold parameters Rc_{0} Rm_{0} with the DFE being unstable when R_{0} > 1; for Rc_{0} < R_{0} < 1; the DFE is LAS and co-exists with at least one LAS endemic equilibrium. We design a NSFD scheme that preserves positivity and boundedness of the solution as well as the above-stated stability properties of equilibria. Numerical simulations that support the theory are provided.

Application of Morphometric Analysis for Geo-Hydrological Studies Using Geo-Spatial Technology –A Case Study of Vishav Drainage Basin

The morphometric analysis of the drainage basin and channel network play an important role in understanding the geo-hydrological behavior of drainage basin and expresses the prevailing climate, geology, geomorphology, structural antecedents of the catchment. Morphometric analysis of a drainage basin expresses fully the state of dynamic balance that has been attained due to dealings between matter and energy. In the present study, morphometric analysis has been carried out using Geographical Information System (GIS) techniques to assess the geo-hydrological characteristics of Vishav drainage basin and an attempt has been made to identify the ground water potential zones through geo-morphometric specs. The morphometric parameters are discussed about linear, areal and relief aspects. The basin is characterized by dendritic to sub-dendritic drainage pattern. The development of stream segments in the basin area is affected by rainfall, groundwater discharge and snow melt over. The analysis has revealed that the total number and length of stream segments is maximum in first order streams and decreases as the stream order increases. The bifurcation ratio (Rb) between different successive orders varies revealing the geostructural control. The shape parameters (Rc=0.52, Re=0.15 and Rf=0.22) indicate the elongated shape of the basin and in association with some areal (Dd, Dt etc.) and relief (H, Sb, etc.) parameters show that it has low discharge of runoff, generally permeable subsoil condition, moderate to high infiltration capacity and good groundwater resource and a flatter peak of flow of longer duration that is easier to manage that of the circular basins. The study reveals that morphometric analysis based on GIS technique is a competent tool for geo-hydrological studies. These studies are very useful for identifying and planning the ground water potential zones and watershed management (including the whole gamut of natural resources connected with the basin).

Core-cusp revisited and dark matter phase transition constrained atO(0.1) eVwith low surface brightness rotation curve

Recently a new particle physics model called Bound Dark Matter (BDM) has been proposed in which dark matter (DM) particles are massless above a threshold energy (Ec) and acquire mass below it due to nonperturbative methods. Therefore, the BDM model describes DM particles which are relativistic, hot dark matter, in the inner regions of galaxies and describes nonrelativistic, cold dark matter, where halo density is below rho_c = Ec^4. To realize this idea in galaxies we use a particular DM cored profile that contains three parameters: a scale length (rs) and density (rho_0) of the halo, and a core radius (rc) stemming from the relativistic nature of the BDM model. We test this model by fitting rotation curves of seventeen Low Surface Brightness galaxies from The HI Nearby Galaxy Survey (THINGS). Since the energy Ec parameterizes the phase transition due to the underlying particle physics model, it is independent on the details of galaxy or structure formation and therefore the DM profile parameters rs, rc, Ec are constrained, leaving only two free parameters. The high spatial and velocity resolution of this sample allows to derive the model parameters through the numerical implementation of the chi^2-goodness-of-fit test to the mass models. We compare the fittings with those of Navarro-Frenk-White (NFW), Burkert, and Pseudo-Isothermal (ISO) profiles. Through the results we conclude that the BDM profile fits better, or equally well, than NFW, Burkert, and ISO profiles and agree with previous results implying that cored profiles are preferred over the N-body motivated cuspy profile. We also compute 2D likelihoods of the BDM parameters rc and Ec for the different galaxies and matter contents, and find an average galaxy core radius rc=300 pc and a transition energy Ec = 0.11 eV when the DM halo is the only component. In Kroupa mass model, we obtain a core rc=1.48 kpc, and energy Ec=0.06 eV.

Hall Effect on Oscillatory Hydromagnetic Free Convective Flow of a Non-Newtonian Fluid past an Infinite Vertical Porous Flat Plate with Heat Sources / Sink and Constant Suction

This paper deals with the hall effect on oscillatory hydromagnetic free convective flow of non-Newtonian fluid past an infinite vertical porous flat plate with heat sources/sinks. In the formulation part, equations of continuity, motion and energy have been developed. These equations have been made dimensionless with the introduction of non-dimensional parameters concerned and solved applying complex variable technique under the boundary conditions employed. Profiles of primary velocity, secondary velocity and temperature have been plotted after computerization with the numerical values of the non-dimensional parameters. The values of skin frictions and the rates of heat transfer have been entered in the tables. It is observed that both the primary and secondary velocity increase with the increase of the non-Newtonian parameters (Rc) as well as the reciprocal of the porosity parameters (1/K*). The temperature of the fluid falls with the Prandtl number (Pr).

Measurement of cross-magnetic-field heat transport due to long-range collisions

Cross-magnetic-field heat transport in a quiescent pure ion plasma is found to be diffusive and to be dominated by long-range “guiding center” collisions. In these long-range collisions, which occur in plasmas with Debye length λD greater than cyclotron radius rc, particles with impact parameters rc&amp;lt;ρ⩽λD exchange parallel kinetic energy only. The resulting thermal diffusivity χL is independent of magnetic field B and plasma density n. The measured thermal diffusivity χ agrees within a factor of 2 with the long-range prediction χL=0.49nv̄b2λD2 over a range of 1000 in temperature, 50 in density, and 4 in magnetic field. This thermal diffusivity is observed to be up to 100 times larger than classical diffusivity from short-range velocity-scattering collisions. These long-range collisions are typically dominant in unneutralized plasmas, and may also contribute to electron heat transport in neutral plasmas.

Electrical and Dielectric Behaviour at the Critical Point of Binary Liquids: Acetonitrile + Cyclohexane

AbstractThe electrical capacitance and resistance of the binary liquid mixture cyclohexane + acetonitrile are measured in the one phase and two phase regions at spot frequencies between 5 kHz and 100 kHz. This sample has a very low gravity affected (∼0.6 mK) region. In one phase region the capacitance data show a sharp, ∼0.7% increase above background within 0.5 degrees of Tc whereas the resistance has a smooth increase of ∼1.5% above background in a (T−Tc) range of 4 degrees. Two phase values of capacitance and resistance from the coexisting phases are used to determine the critical parameters Tc (critical temperature), Rc (resistance at Tc) and Cc (capacitance at Tc). A precise knowledge of these parameters reduces the uncertainty on the critical exponent 0 for C and R. The one phase capacitance data fit to an (1 ‐ α) exponent in a limited temperature range of 0.2 degrees. Resistance data strongly support an (1 ‐ α) exponent over the entire 5 degree range.

Electron diffraction investigation of the molecular structures of ethyl isocyanate and ethyl isothiocyanate

Electron diffraction (ED) measurements and published microwave spectra are used to define the molecular structures of ethyl isocyanate and ethyl isothiocyanate in the gas phase. A cis-conformation is compatible with the data in both cases, while ED data for EtNCO are also consistent with a deviation of 45° from the cis conformation. An interpretation (in general terms) of the very complex microwave spectra in terms of an anharmonic two-dimensional motion combining the bend at nitrogen and the CN torsion is proposed. An average cis structure ( r* av basis) consistent with ED and microwave data with removal of the effects of the torsional motion is proposed in each case, with skeletal parameters (NCO, NCS) rCN 144.8 pm, 143.8; rCC 152.4, 152.0 pm; rNC 121.8 pm, 118.7; rCO 117.4 pm, rCS 158.0 pm; ∠CCN 114.7°, 111.0°; ∠CNC 132.2°, 147,4°; ∠NCO 192.2°, ∠NCS 184.5°.

A Study in the Homology of Lattice Mechanical Properties of Alkali Metals

AbstractThe nature of the dependence of the Heine‐Abarenkov model pseudopotential parameters rc and u for different alkali metals, obtained through a comprehensive unified study of the metals, on the atomic number, Z, is investigated, leading to simple empirical relations between Z and the parameters. The product of Z1/2 and the dynamical matrix, D, calculated using the parameters yielded by these relations is found to satisfy a relation of the form DZ1/2 = C1(q, e) for various Z‐values, C1(q, e) being a constant depending on the phonon wave vector q and the polarization e. This at once leads to the relation m1/2Z1/4v = C2(q, e) which is verified empirically and thus implies that the lattice vibrations of alkali metals are homologous. The relations obtained are used for a comprehensive unified study of Cs and for predicting its dispersion relation. The importance of the approach lies in the fact that knowing only Z, a unified study of a large number of lattice static, dynamic, and electronic properties of any alkali metal can be carried out within the framework of the pseudopotential theory.

Elasticoviscous flow along a plane wall with periodic suction

The flow of an elasticoviscous liquid past an infinte wall with periodic suction is discussed. Approximate solutions of the velocity fields and the pressure field have been obtained. The effect of the parameters Re (Reynolds number) and Rc (elastic parameter) on the quasi-two-dimensional corrections in the case of the velocity fields, pressure field, and skin friction have been discussed.

The elastic small angle scattering of ions at atoms in the high energy region. II. Comparison with experimental results

For pt. I see abstr. A33056 of 1973. Using the theoretical results of pt. I experimental data of the scattering of 7Li+-ions at Ar are evaluated. From the diffraction effect detailed statements about the repulsive term of the interaction potential are given. The simple Yukawa type screened Coulomb potential is very well suited for describing the small angle scattering between ions and atoms. A modification of this potential can be clearly excepted. The evaluation method for determining the potential parameters is described in detail and gives for 7Li+-Ar the parameters Rc=0.289 AA and Aaeff=54. In the region of the first undulation maximum the influence of the attractive potential term is found experimentally. Certainly the experiments show with decreasing scattering angle a shape of approximately 1/ Theta 2 which is caused by inelastic scattering.

Flow of Elasticoviscous Liquid between Rotating Cylinders with Suction and Injection

The steady-state laminar flow of an incompressible elasticoviscous liquid in an annulus with coaxial porous walls, rotating about a common axis is considered. The rate of fluid injection at one wall is taken to be equal to the rate of fluid suction at the other. The flow phenomenon has been characterized by the nondimensional parameters Rc (elastic number), R (cross-flow Reynolds number), m (ratio of the angular velocities of the cylinders), and σ (radii ratio). A small perturbation method has been used to obtain an approximate solution for the velocity field. The perturbation method is in powers of R and, thus, valid for sufficiently small |R|, but general Rc. A perturbation method in powers of Rc has also been used to obtain an approximate solution of the velocity field. This solution should be valid for sufficiently small |Rc| but general R. The effects of the above parameters on the velocity distribution, shear stress at the walls, and the radial pressure variation have been studied.

Heat transfer by laminar flow of elastico-viscous liquids through parallel walls

The heat transfer by laminar flow of elastico-viscous liquids has been studied by using the constitutive equations of motion for elastico-viscous liquids and energy equation. The plane Poiseuille flow has been examined in detail and is found to be characterized by two parameters Rc and S. The presence of the elastic elements in the viscous liquids is found to decrease the velocity and temperature at any point if the walls are at constant temperature, but the elastic elements increase the temperature at any point if the walls are having linearly varying temperature.