Calculation Of Distribution Function Research Articles

Cooperative Vehicle Speed Fault Diagnosis and Correction

Reliable estimation of vehicle speed is an active topic of research in the automotive industry and academia due to its technical challenges as well as applications to vehicle traction and stability control. In this direction, the emergence of new generations of communication technologies has brought new perspectives to traditional studies on vehicle speed estimation and control. To this end, this paper introduces a cooperative vehicle speed fault diagnosis and correction algorithm. The distributed part of the algorithm is based on a distributed function calculation algorithm for vehicle networks. The introduced algorithm enables each vehicle to gather some information from other vehicles in the network in a distributed manner and is robust to communication failures. A procedure to use such information for a single vehicle to diagnose and correct a possible fault in its own speed estimation/measurement is discussed. The functionality and performance of the proposed algorithms are verified via illustrative examples and simulation results.

Power corrections and renormalons in parton quasidistributions

Perturbative expansions for short-distance quantities in QCD are factorially divergent and this deficiency can be turned into a useful tool to investigate nonperturbative corrections. In this work, we use this approach to study the structure of power corrections to parton quasi-distributions and pseudo-distributions which appear in lattice calculations of parton distribution functions. As the main result, we predict the functional dependence of the leading power corrections to quasi(pseudo)-distributions on the Bjorken $x$ variable. We also show that these corrections can be strongly affected by the normalization procedure.

Transversity parton distribution functions from lattice QCD

We present the first direct calculation of the transversity parton distribution function within the nucleon from lattice QCD. The calculation is performed using simulations with the light quark mass fixed to its physical value and at one value of the lattice spacing. Novel elements of the calculations are non-perturbative renormalization and extraction of a formula for the matching to light-cone PDFs. Final results are presented in the $\overline{\rm MS}$ scheme at a scale of $\sqrt{2}$ GeV.

Molecular dynamics simulation of fluid flow passing through a nanochannel: Effects of geometric shape of roughnesses

In this paper, we investigate the effects of geometric shape of various roughnesses on the fluid flow passing through a nanochannel by using of molecular dynamics simulation. The results of simulations are presented for the modeled structures (the five models defined) as number density, velocity, and system temperature profiles for various conditions. By applying roughness to the inner surface of the ideal nano-channel at a thrust force of 0.002 eV/Å, the amplitude of number density of the fluid particles near the walls decreased, while the mean and maximum velocities increased by 6.5% and 2.5% in the presence of square cuboid and hemispheroid roughness, respectively. Furthermore, the dimensionless slip velocity and slip length were, respectively, increased by a maximum of 41.1% and 21.5% in the presence of square cuboid roughness and by a minimum of 0.9% and 0.5% in the presence of hemispheroid roughness. The temperature of the particles at the center of the nano-channel was increased by a maximum of 9.1% and a minimum of 2.8% in the presence of square cuboid and hemispheroid roughness, respectively. Calculation of the Argon-Argon radial distribution function indicated that the maximum of this function decreased by a maximum of 11.8% and a minimum of 8.5% in the presence of rectangular cuboid and ellipsoid roughness, respectively, compared to the ideal nano-channel.

Effects of Ar Addition to O2 Plasma on Plasma-Enhanced Atomic Layer Deposition of Oxide Thin Films

A method for significantly increasing the growth rates (GRs) of high- k oxide thin films grown via plasma-enhanced atomic layer deposition (PE-ALD) by enhancing the plasma density through the addition of Ar gas to the O2 plasma oxidant was developed. This approach led to improvements of ∼60% in the saturation GRs of PE-ALD ZrO2, HfO2, and SiO2. Furthermore, despite the significantly higher GR enabled by PE-ALD, the mechanical and dielectric properties of the PE-ALD oxide films were similar or even superior to those of films grown via the conventional O2 plasma process. Optical emission spectroscopy analyses in conjunction with theoretical calculation of the electron energy distribution function revealed that adding Ar gas to the O2 plasma increased the density of high-energy electrons, thereby generating more O2 plasma species, such as ions and radicals, which played a key role in improving the GRs and the properties of the films. This promising approach is expected to facilitate the high-volume manufacturing of films via PE-ALD, especially for use as gate insulators in thin-film transistor-based devices in the display industry.

ФОРМУЛА ОБРАЩЕНИЯ ДЛЯ РАЦИОНАЛЬНЫХ ХАРАКТЕРИСТИЧЕСКИХ ФУНКЦИЙ ВЕРОЯТНОСТНЫХ РАСПРЕДЕЛЕНИЙ

The paper deals with the problem of clarifying the well-known inversion formulas for distribution functions, usually describing the increment of these functions. The validity of the corresponding inversion formulas for the distribution function π and their densities has been proved for the particular case of distributions with rational characteristic functions. The obtained formulas for distribution functions, which include additionally constant terms equal to 0.5, were not previously known. Functions of positively distributed random variables and quantities distributed over the entire axis have been considered separately. To test the hypothesis of fairness of the obtained treatment formula, including a previously unknown term equal to 0.5, in the general case there have been given examples of calculating distribution functions, whose characteristic functions are not considered as rational functions: for constant and uniform laws. The verification confirmed the objectiveness of the formulated hypothesis about the obtained validity of the inversion form for arbitrary distribution functions. It has also been shown that any distribution function and any density can be represented as a limit of a mixture of gamma distributions (distribution functions and densities), having shifts along the abscissa axis and, possibly, with altered signs of the arguments. The obtained result proves that the set of gamma distributions with shifted arguments is uniformly dense in the set of all distributions.

Spectroscopic, antimicrobial and computational study of novel benzoxazole derivative

A benzoxazole derivative, 2-(p-methylphenyl)-5-(2-(4-ethylpiperazine-1-yl)acetamido) benzoxazole (PMPEPAB) has been synthesized and investigated for its spectroscopic properties within the framework of density functional theory (DFT) calculations and molecular dynamics (MD) simulations. Potential energy distribution analysis was employed in order to assign and compare computationally and experimentally obtained wavenumbers. It was identified that the title compound exhibits antibacterial activity against Gram-positive, Gram-negative bacteria and their drug-resistant isolates and a fungus; Candida albicans. TD-DFT calculations have been used in order to understand charge transfer within PMPEPAB. Natural bond orbital analysis has been carried out to investigate stability of the molecule arising from charge delocalization and hyper-conjugative interactions. Local reactivity properties have been assessed using the MEP and ALIE surfaces and Fukui functions. Stability in water and sensitivity towards hydrolysis has been investigated by MD simulations and calculations of radial distribution functions, while sensitivity towards autoxidation mechanism has been studied by DFT calculations of bond dissociation energies for hydrogen abstraction. Drug likeness parameters are very competitive, while the binding affinity of the title compound with immunoglobulin tandem protein is −6.4 kcal/mol, indicating that title molecule is a candidate to be active component of a new drug for muscular dystrophy.

A model calculation of double parton distribution functions of the pion

Two-parton correlations in the pion are investigated in terms of double parton distribution functions. A Poincaré covariant light-front framework has been adopted. As non perturbative input, the pion wave function obtained within the so-called soft-wall AdS/QCD model has been used. Results show how novel dynamical information on the structure of the pion, not accessible through one-body quantities, are encoded in double parton distribution functions.

Plasma states and carbon film deposition in glow discharge connected to dielectric barrier discharge

We developed a plasma source by connecting a direct current glow discharge (GD) with a dielectric barrier discharge (DBD) via a ground mesh (DB-GD). Based on the Langmuir probe measurements, the electron density of the DB-GD increased and the electron temperature decreased compared with those of the GD. Calculations of the electron energy distribution functions revealed that the DB-GD possessed a lower density of high-energy electrons and higher density of low-energy electrons than the GD did. We also confirmed that the DB-GD generated with methane gas was capable of producing an amorphous carbon film.

Molecular dynamics simulation of self-assembly and viscosity behavior of PAM and CTAC in salt-added solutions

In this study, the self-assembly of cationic surfactant cetyltrimethyl ammonium chloride (CTAC) and nonionic polymer polyacrylamide (PAM) in aqueous solution with added sodium salicylate (NaSal) as counter-ion salt is studied using a coarse-grained molecular dynamic simulation (CGMD). The microstructure evolution shows that in the mixed solutions, surfactant micelles are readily to associate with polymer and can form a new complex of CTAC and PAM with interconnected network structures, which can be attributed to the hydrophobic interactions, the attraction between acylamino and the head of CTAC, and the attraction between Sal− and acylamino. The calculation of radial distribution function for different sites also proved the aggregate of the surfactant and polymer. Then a reverse non-equilibrium molecular dynamics (RNEMD) simulation is used to investigate the rheological property of the mixed solutions, the CTAC/NaSal solution and the PAM solution. The molecular dynamics simulation demonstrates that the viscosity of the CTAC/PAM/NaSal solution is significantly higher than that of the CTAC/NaSal solution, mainly because the surfactant micelles interacted with the polymer and formed rod-like micelles.

Nonperturbative Renormalization of Nonlocal Quark Bilinears for Parton Quasidistribution Functions on the Lattice Using an Auxiliary Field

Parton quasidistribution functions provide a path toward an abinitio calculation of parton distribution functions (PDFs) using lattice QCD. One of the problems faced in calculations of quasi-PDFs is the renormalization of a nonlocal operator. By introducing an auxiliary field, we can replace the nonlocal operator with a pair of local operators in an extended theory. On the lattice, this is closely related to the static quark theory. In this approach, we show how to understand the pattern of mixing that is allowed by chiral symmetry breaking and obtain a master formula for renormalizing the nonlocal operator that depends on three parameters. We present an approach for nonperturbatively determining these parameters and use perturbation theory to convert to the modified minimal subtraction (MS[over ¯]) scheme. Renormalization parameters are obtained for two lattice spacings using Wilson twisted mass fermions and for different discretizations of the Wilson line in the nonlocal operator. Using these parameters, we show the effect of renormalization on nucleon matrix elements with a pion mass of approximately 370MeV and compare renormalized results for the two lattice spacings. The renormalized matrix elements are consistent among the different Wilson line discretizations and lattice spacings.

Molecular insights on the interfacial and transport properties of supercritical CO2/brine/crude oil ternary system

In this study, we conducted a series of molecular dynamics simulations to investigate the effect of supercritical carbon dioxide (sc-CO2) on the interfacial and transport properties of brine/crude oil at the reservoir conditions. We also studied the interfacial behavior of asphaltenes in presence of CO2. Crude oil was resembled by several hydrocarbons which are hexane, heptane, octane, nonane, cyclohexane, cycloheptane, benzene and toluene. The results showed that CO2, aromatics and asphaltenes accumulate at the interface at low CO2 mole fraction, however, as CO2 mole fraction increases, the relative density, the ratio of the density at the interface to the bulk density, decreases for both CO2 and aromatics. The decrease in CO2 relative density is due to the amount of CO2 dissolved in the oil bulk, which increases as CO2 mole fraction increase. It also found that CO2 displaces the oil molecules away from the interface, thus the relative density of aromatics decreases. Interestingly, it was found that as CO2 mole fraction increase, it enhances the face-to-face stacking between asphaltene molecules as noticed from the radial distribution function calculations. CO2 also force some asphaltene molecules to leave the interface and being dissolved and aggregated in the oil bulk. It also found that as CO2 mole fraction increased in the system, it dilutes the interface, penetrates to the water phase, forms hydrogen bonds with water and due to these effects, it reduces the interfacial tension of brine/crude oil system. The diffusivity of supercritical CO2/brine/crude oil system was also increased as a function of CO2 mole fraction. This study provides insights of the underlying interfacial properties from molecular level for a more realistic system of brine/crude oil.

On the power divergence in quasi gluon distribution function

Recent perturbative calculation of quasi gluon distribution function at one-loop level shows the existence of extra linear ultraviolet divergences in the cut-off scheme. We employ the auxiliary field approach, and study the renormalization of gluon operators. The non-local gluon operator can mix with new operators under renormalization, and the linear divergences in quasi distribution function can be into the newly introduced operators. After including the mixing, we find the improved quasi gluon distribution functions contain only logarithmic divergences, and thus can be used to extract the gluon distribution in large momentum effective theory.

Matching the quasiparton distribution in a momentum subtraction scheme

The quasi parton distribution is a spatial correlation of quarks or gluons along the $z$ direction in a moving nucleon which enables direct lattice calculations of parton distribution functions. It can be defined with a nonperturbative renormalization in a regularization independent momentum subtraction scheme (RI/MOM), which can then be perturbatively related to the collinear parton distribution in the $\overline{\text{MS}}$ scheme. Here we carry out a direct matching from the RI/MOM scheme for the quasi-PDF to the $\overline{\text{MS}}$ PDF, determining the non-singlet quark matching coefficient at next-to-leading order in perturbation theory. We find that the RI/MOM matching coefficient is insensitive to the ultraviolet region of convolution integral, exhibits improved perturbative convergence when converting between the quasi-PDF and PDF, and is consistent with a quasi-PDF that vanishes in the unphysical region as the proton momentum $P^z\to \infty$, unlike other schemes. This direct approach therefore has the potential to improve the accuracy for converting quasi-distribution lattice calculations to collinear distributions.

4-[(4-acetylphenyl)amino]-2-methylidene-4-oxobutanoic acid, a newly synthesized amide with hydrophilic and hydrophobic segments: Spectroscopic characterization and investigation of its reactive properties

The FT-IR and FT-Raman spectra of 4-[(4-acetylphenyl)amino]-2- -methylidene-4-oxobutanoic acid were recorded. The vibrational wave numbers were computed by DFT quantum chemical calculations and the vibrational assignments were realized using the potential energy distribution. The theoretically predicted geometrical parameters were in agreement with the XRD data. Determination and visualization of molecule sites prone to electrophilic attacks were performed by mapping the average local ionization energies (ALIE) to the electron density surface. Furthermore, determination of possible reactive centres of title molecule was realized by calculation of the Fukui functions. Intramolecular non-covalent interactions were also determined and visualized. In addition, prediction of molecule sites possibly prone to autoxidation was performed by calculation of the bond dissociation energies (BDE), while the stability of the title molecule in water was assessed by calculation of radial distribution functions (RDF) obtained after molecular dynamics (MD) simulations. The docked title ligand compound forms a stable complex with insulin receptor kinase and gives a binding affinity of ?10.2 kcal* mol-1.

Preferential solvation, ion pairing, and dynamics of concentrated aqueous solutions of divalent metal nitrate salts.

We have investigated the characteristics of preferential solvation of ions, structure of solvation shells, ion pairing, and dynamics of aqueous solutions of divalent alkaline-earth metal nitrate salts at varying concentration by means of molecular dynamics simulations. Hydration shell structures and the extent of preferential solvation of the metal and nitrate ions in the solutions are investigated through calculations of radial distribution functions, tetrahedral ordering, and also spatial distribution functions. The Mg2+ ions are found to form solvent separated ion-pairs while the Ca2+ and Sr2+ ions form contact ion pairs with the nitrate ions. These findings are further corroborated by excess coordination numbers calculated through Kirkwood-Buff G factors for different ion-ion and ion-water pairs. The ion-pairing propensity is found to be in the order of Mg(NO3)2 < Ca(NO3)2 < Sr(NO3)2, and it follows the trend given by experimental activity coefficients. It is found that proper modeling of these solutions requires the inclusion of electronic polarization of the ions which is achieved in the current study through electronic continuum correction force fields. A detailed analysis of the effects of ion-pairs on the structure and dynamics of water around the hydrated ions is done through classification of water into different subspecies based on their locations around the cations or anions only or bridged between them. We have looked at the diffusion coefficients, relaxation of orientational correlation functions, and also the residence times of different subspecies of water to explore the dynamics of water in different structural environments in the solutions. The current results show that the water molecules are incorporated into fairly well-structured hydration shells of the ions, thus decreasing the single-particle diffusivities and increasing the orientational relaxation times of water with an increase in salt concentration. The different structural motifs also lead to the presence of substantial dynamical heterogeneity in these solutions of strongly interacting ions. The current study helps us to understand the molecular details of hydration structure, ion pairing, and dynamics of water in the solvation shells and also of ion diffusion in aqueous solutions of divalent metal nitrate salts.

Archimedean Copula Estimation Parameter with Kendall Distribution Function

In the literature, up to now, it is common that for Gumbel, Clayton and Frank calculated Kendall Distribution function and to the extent those applications have been made. In this paper, we made Kendall Distribution function calculation for Ali Mikhail Haq and Joe and in relation that simulation study. We generated dependent gamma distribution. For dependency between these variables we used Archimedean copula. In connection with this, we define basic properties of copulas and their nonparametric method. In this study, to explain the relationship between the variables, five Archimedean copula families were used; Gumbel, Clayton, Frank Joe and Ali Mikhail Haq. We obtained nonparametric estimation of these copula families parameters and the suitable Archimedean copula family for this data set.

Nucleon transverse momentum-dependent parton distributions in lattice QCD: Renormalization patterns and discretization effects

Lattice QCD calculations of transverse momentum-dependent parton distribution functions (TMDs) in nucleons are presented, based on the evaluation of nucleon matrix elements of quark bilocal operators with a staple-shaped gauge connection. Both time-reversal odd effects, namely, the generalized Sivers and Boer-Mulders transverse momentum shifts, as well as time-reversal even effects, namely, the generalized transversity and one of the generalized worm-gear shifts are studied. Results are obtained on two different $n_f = 2+1$ flavor ensembles with approximately matching pion masses but very different discretization schemes: domain-wall fermions (DWF) with lattice spacing $a=0.084$ fm and pion mass 297 MeV, and Wilson-clover fermions with $a=0.114$ fm and pion mass 317 MeV. Comparison of the results on the two ensembles yields insight into the length scales at which lattice discretization errors are small, and into the extent to which the renormalization pattern obeyed by the continuum QCD TMD operator continues to apply in the lattice formulation. For the studied TMD observables, the results are found to be consistent between the two ensembles at sufficiently large separation of the quark fields within the operator, whereas deviations are observed in the local limit and in the case of a straight link gauge connection, which is relevant to the studies of parton distribution functions. Furthermore, the lattice estimates of the generalized Sivers shift obtained here are confronted with, and are seen to tend towards, a phenomenological estimate extracted from experimental data.

Combined spectroscopic, DFT, TD-DFT and MD study of newly synthesized thiourea derivative

A novel thiourea derivative, 1-(3-bromophenyl)-3-[3-(trifluoromethyl)phenyl]thiourea (ANF-22) is synthesized and characterized by FTIR, FT-Raman and NMR spectroscopy experimentally and theoretically. A detailed conformational analysis of the title molecule has been conducted in order to locate the lowest energy geometry, which was further subjected to the detailed investigation of spectroscopic, reactive, degradation and docking studies by density functional theory (DFT) calculations and molecular dynamics (MD) simulations. Time dependent DFT (TD-DFT) calculations have been used also in order to simulate UV spectra and investigate charge transfer within molecule. Natural bond orbital analysis has been performed analyzing the charge delocalization and using HOMO and LUMO energies the electronic properties are analyzed. Molecular electrostatic potential map is used for the quantitative measurement of active sites in the molecule. In order to determine the locations possibly prone to electrophilic attacks we have calculated average local ionization energies and mapped them to the electron density surface. Further insight into the local reactivity properties have been obtained by calculation of Fukui functions, also mapped to the electron density surface. Possible degradation properties by the autoxidation mechanism have been assessed by calculations of bond dissociation energies for hydrogen abstraction. Atoms of title molecule with significant interactions with water molecules have been determined by calculations of radial distribution functions. The title compound can be a lead compound for developing new analgesic drug.

Transverse-momentum-dependent quark distribution functions of spin-one targets: Formalism and covariant calculations

We present a covariant formulation and model calculations of transverse momentum-dependent quark distribution functions (TMDs) for spin-one hadrons. Emphasis is placed on a description of these 3-dimensional distribution functions which is independent of any constraints on the spin quantization axis. We apply our covariant spin description to all nine leading-twist time-reversal even $\rho$ meson TMDs in the framework provided by the Nambu--Jona-Lasinio model, incorporating important aspects of quark confinement via the infrared cut-off in the proper-time regularization scheme. In particular, the behavior of the 3-dimensional TMDs in a tensor polarized spin-one hadron are illustrated. Sum rules and positivity constraints are discussed in detail. Results of particular interest include the finding that the tensor polarized TMDs -- associated with spin-one hadrons -- are very sensitive to quark orbital angular momentum, and that the TMDs associated with the quark operator $\gamma^+\boldsymbol{\gamma}_T\gamma_5$ would vanish were it not for dynamical chiral symmetry breaking. In addition, we find that 44% of the $\rho$ meson's spin is carried by the orbital angular momentum of the quarks, and that the magnitude of the tensor polarized quark distribution function is about 30% of the unpolarized quark distribution. A qualitative comparison between our results for the tensor structure of a quark-antiquark bound state is made to previous experimental and theoretical results for the two-nucleon (deuteron) bound state.