Calculation Of Moments Research Articles

Auxiliary field diffusion Monte Carlo calculations of magnetic moments of light nuclei with chiral effective field theory interactions

Auxiliary field diffusion Monte Carlo calculations of magnetic moments of light nuclei with chiral effective field theory interactions

Strong ultrafast demagnetization due to the intraband transitions

Demagnetization in ferromagnetic transition metals driven by a femtosecond laser pulse is a fundamental problem in solid state physics, and its understanding is essential to the development of spintronic devices. Ab initio calculation of time-dependent magnetic moment in the velocity gauge so far has not been successful in reproducing the large amount of demagnetization observed in experiments. In this work, we propose a method to incorporate intraband transitions within the velocity gauge through a convective derivative in the crystal momentum space. Our results for transition-element bulk crystals (bcc Fe, hcp Co and fcc Ni) based on the time-dependent quantum Liouville equation show a dramatic enhancement in the amount of demagnetization after the inclusion of an intraband term, in agreement with experiments. We also find that the effect of intraband transitions on each ferromagnetic material is distinctly different because of their band structure and spin property differences. Our finding has a far-reaching impact on understanding of ultrafast demagnetization.

Computational simulation on the study of Tacrolimus and its improved dermal retention using Poly(Ԑ-caprolactone) nanocapsules

Tacrolimus (TAC) is a drug from natural origin that can be used for topical application to control autoimmune skin diseases such as atopic dermatitis, psoriasis, and vitiligo. Computational simulation based on quantum mechanics theory by solving Schrödinger Equation for n-body problem may allow the theoretical calculation of drug geometry, charge distribution and dipole moment, electronic levels and molecular orbitals, electronic transitions, and vibrational transitions. Additionally, the development of novel nanotechnology-based delivery systems containing TAC can be an approach for reducing the dose applied topically, increasing dermal retention, and reducing the reported side effects due to the controlled release pattern. Firstly, this paper was devoted to obtaining the molecular, electronic, and vibrational data for TAC by using five semi-empirical (SE) methods and one Density Functional Theory (DFT) method in order to expand the knowledge about the drug properties by computational simulation. Then, this study was carried out to prepare TAC-loaded poly(ԑ-caprolactone) nanocapsules by interfacial polymer deposition following solvent displacement and investigate the in vitro drug permeation using the Franz diffusion cell and the photoacoustic spectroscopy. Computational simulations were compared in the three schemes SE/SE, SE/DFT, and DFT/DFT, where the first method represented the procedure used for geometry optimization and the second one was performed to extract electronic and vibrational properties. Computational data showed correspondence with TAC geometry description and electronic properties, with few differences in HOMO – LUMO gap (Δ) and dipole values. The SE/DFT and DFT/DFT methods presented a better drug description for the UV–Vis, Infrared, and Raman spectra with low deviation from experimental values. Franz cell model demonstrated that TAC was more delivered across the Strat-M® membrane from the solution than the drug-loaded poly(ԑ-caprolactone) nanocapsules. Photoacoustic spectroscopy assay revealed that these nanocapsules remained more retained into the Strat-M® membranes, which is desirable for the topical application.

Model based aircraft design and optimization: a case study with cessna 172N aircraft

Abstract This study aims to create an interdisciplinary, multi-level design approach for fixed wing aircrafts. A case study is performed using Cessna 172N aircraft characteristics that is based on a mathematical model having six degrees of freedom (DOF). A Model Based Aircraft Design Software (MAD) is developed using a mathematical dynamic model in Python environment for use in the optimization phase of the Cessna 172N aircraft. The MAD environment is composed of analysis tools that communicate with each other by an automated process chain system. The model includes aerodynamics, engine, mass, control, atmosphere, and landing gear submodules. In addition, the model has trim and 6 DOF simulation analysis capabilities which provide a diversity of analyses that can be considered in early design phases. In order to get trimming and simulation capability, MAD software does not need any precalculated aerodynamic database. The force and moment calculations are performed instantly via DATCOM and AVL solvers for each iteration of simulation or trim. Thanks to this method, alternative aircraft geometries can be compared at the first phase of the design and optimization processes without creating an overall database. All methodologies of model submodules, performance, stability and control calculations, design, and optimization applications are implemented in the MAD environment.

Absorption Line Oscillator Strengths for the C 2Π(0)-A 2Σ+(0) Band of Nitric Oxide

We have determined absorption oscillator strengths for rotational transitions of the C 2Π(0)-A 2Σ+(0) band of NO, which has been detected in the upper atmosphere of Venus. The molecular quantum defect orbital method has been used in the calculation of the electronic transition moment and the Rydberg–valence interaction between the C 2Π(v = 0) and the B 2Π (v = 7) states has been considered. Considerable deviations from normal intensity distribution of the rotational lines have been found at J ≤ 5.5. As far as we know, the present line f-values are reported here for the first time. These data may be useful in the interpretation of the observations obtained by the Visible and Infrared Thermal Imaging Spectrometer instrument on the Venus Express spacecraft.

Fast fractional-order polar linear canonical transform: Theory and application

Zero-watermarking is a promising technology for image copyright protection due to its excellent imperceptibility and robustness. Compared with deep learning (DL)-based zero-watermarking schemes which are time-consuming and unable to respond in real-time, the moment-based zero-watermarking schemes do not have the aforementioned drawbacks and have drawn great attention with their strong description ability and geometric invariance. However, most existing moment-based zero-watermarking methods bear a number of drawbacks, in particular: (i) Direct computation of image moments is inefficient and inaccurate; (ii) They have difficulty obtaining the favorable trade-off between robustness and discriminability; (iii) Generating pseudo-random numbers based on traditional logistic map results in their lower security performance. To deal with those issues, this paper introduces a new image zero-watermarking method that relies on fast fractional-order polar linear canonical transform (FFrPLCT) features and asymmetric tent map. Firstly, we propose a novel computation strategy called fast polar linear Canonical transform (FPLCT), to save the calculation time of moments. Secondly, we define the fast fractional-order polar linear Canonical transform (FFrPLCT), which is characterized by the generic nature and time-frequency analysis capability. Thirdly, we present the FFrPLCT mixed low-order features by fully exploiting the time-frequency property of FFrPLCT, to improve both the robustness and discriminability of image representation. Finally, we develop a new image zero-watermarking method using FFrPLCT domain mixed low-order features and asymmetric tent map. Experimental results and comparison with well-known existing methods demonstrate the efficacy and superiority of the proposed image zero-watermarking scheme.

Calculation Method of Deceleration Lane Length and Slope Based on Reliability Theory

The deceleration lane is an important part of the freeway, and the rationality of its design parameters affects the exit accident rate. The traditional calculation method is based on the design of speed and vehicle parameters using deterministic methods, ignoring the randomness of the driver’s deceleration behavior. It is necessary to calculate the length and slope of the deceleration lane in detail according to the deceleration characteristics of the driver in the deceleration section by using the uncertainty method. This paper describes a study on the maximum longitudinal slope of the downhill section of the deceleration lane, where the safety of diverging vehicles is unfavorable. By collecting deceleration lane data from interchanges around Xi’an (Shaanxi Province, China, Coordinates: 108.95, 34.27) and analyzing the deceleration characteristics of vehicles, we propose a new deceleration model. In addition, the limit-state functions of the length and slope of the deceleration lane have been established based on the reliability theory. Finally, according to the deceleration characteristics, we determined the probability distribution of key parameters in the vehicle deceleration process. We used the Monte Carlo Simulation (MCS) and the Improved First-Order Second Moments (IFOSM) calculation model to calculate the length and slope of the deceleration lane, respectively. Finally, we propose the recommended values for the length and slope of the deceleration lane. The results of the study showed that: (1) The movement process of the vehicle on the deceleration section adopts a uniform deceleration, and the truck and the car start to decelerate from the starting of the taper section and diverging point, respectively. (2) The control vehicle in the deceleration lane calculation model is the compact car. (3) The reliability theory has good applicability in calculating freeway alignment indexes. It fully considers the probability of driver deceleration behavior in the calculation model, which provides a more suitable method for the calculation of deceleration lane indexes.

Effect of Fluoride Atoms on the Electrochemical Performance of Tetracyanoquinodimethane(TCNQ) Electrodes in Zinc-ion Batteries.

Tetracyanoquinodimethane (TCNQ) electrode material has achieved excellent performance in aqueous zinc-ion batteries (AZIBs). However, fundamental understanding about effect of substitutes on electrochemical performance of TCNQ remain unknown. In this work, the effects of fluorine (F) as an electron-absorbing group on the structure, morphology and electrochemical performance of TCNQ and storage mechanism of TCNQ in AZIBs are discussed. Theoretical calculation proves that the introduction of fluorine atoms decreases lowest unoccupied molecular orbital (LUMO) energy of TCNQ thus affect the redox potential. Electrochemical performance of TCNQ/Fluoro-7,7,8,8-tetracyanoquinodimethane (FTCNQ)/2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4 TCNQ) is evaluated from 25 °C to -20 °C in AZIBs. Results tend out that with the increasing substituents of F on TCNQ molecular, their stability in AZIBs decrease. Dipole moment calculation further shows that the introduction of fluorine atoms is inconducive to the stability of the electrode material in aqueous solution. Ex-situ characterization demonstrate that electron withdrawing groups do not change the REDOX center of TCNQ electrode materials. Our work provides a new thought for the selection of the electrode material in AZIBs.

Fast and accurate computation of polar harmonic Fourier moments for image description.

Continuous orthogonal moments are widely used in various image techniques due to their simplicity and good rotational invariance and stability. In recent years, numerous excellent continuous orthogonal moments have been developed, among which polar harmonic Fourier moments (PHFMs) exhibit strong image description capabilities. However, the numerical integration error is large in the calculation, which seriously affects the calculation accuracy, especially in higher-order calculation. In this paper, a continuous orthogonal moments-fast and accurate PHFM (FAPHFM) is proposed. It utilizes the polar pixel tiling technique to reduce numerical errors in the computation; this method particularly improves the accuracy of higher-order moments of traditional PHFMs. However, as accuracy increases, calculation complexity also increases. To address this issue, an eight-way symmetric/anti-symmetric calculation of the angular and radial functions was performed using the symmetry and anti-symmetry of traditional PHFMs, and clustering of pixels was performed as a way to improve the computational speed. The experimental results show that FAPHFMs perform better in image reconstruction (including noise), with higher computational accuracy, lower time complexity, and better image description ability.

Model Counting Meets F 0 Estimation

Constraint satisfaction problems (CSPs) and data stream models are two powerful abstractions to capture a wide variety of problems arising in different domains of computer science. Developments in the two communities have mostly occurred independently and with little interaction between them. In this work, we seek to investigate whether bridging the seeming communication gap between the two communities may pave the way to richer fundamental insights. To this end, we focus on two foundational problems: model counting for CSP’s and computation of zeroth frequency moments ( F 0 ) for data streams. Our investigations lead us to observe a striking similarity in the core techniques employed in the algorithmic frameworks that have evolved separately for model counting and F 0 computation. We design a recipe for translating algorithms developed for F 0 estimation to model counting, resulting in new algorithms for model counting. We also provide a recipe for transforming sampling algorithm over streams to constraint sampling algorithms. We then observe that algorithms in the context of distributed streaming can be transformed into distributed algorithms for model counting. We next turn our attention to viewing streaming from the lens of counting and show that framing F 0 estimation as a special case of #DNF counting allows us to obtain a general recipe for a rich class of streaming problems, which had been subjected to case-specific analysis in prior works. In particular, our view yields an algorithm for multidimensional range efficient F 0 estimation with a simpler analysis.

Geometric sieve over number fields for higher moments

The geometric sieve for densities is a very convenient tool proposed by Poonen and Stoll (and independently by Ekedahl) to compute the density of a given subset of the integers. In this paper we provide an effective criterion to find all higher moments of the density (e.g. the mean, the variance) of a subset of a finite dimensional free module over the ring of algebraic integers of a number field. More precisely, we provide a geometric sieve that allows the computation of all higher moments corresponding to the density, over a general number field K. This work advances the understanding of geometric sieve for density computations in two ways: on one hand, it extends a result of Bright, Browning and Loughran, where they provide the geometric sieve for densities over number fields; on the other hand, it extends the recent result on a geometric sieve for expected values over the integers to both the ring of algebraic integers and to moments higher than the expected value. To show how effective and applicable our method is, we compute the density, mean and variance of Eisenstein polynomials and shifted Eisenstein polynomials over number fields. This extends (and fully covers) results in the literature that were obtained with ad-hoc methods.

The multipolar elastic fields of ellipsoidal and polytopal plastic inclusions

The article offers a general formulation for the multipolar field expansion of an inclusion. The multipolar moments of arbitrary order for the ellipsoidal inclusion are derived, showing known features of their elastic fields in both the far and near field. Using integer point enumeration theory, the same formulation is extended to all polytopal inclusions, which serve to model faceted inclusions found in, e.g. igneous and metamorphic rocks, particle reinforced composite materials, or as intermetallic precipitates in alloys. A general algorithm for the calculation of the multipolar moments of polytopes of any number of vertices is derived. A number of examples for tetrahedral, cuboidal and dodecahedral inclusions are given. It is shown that the parity of the axial moment function of a polytopal inclusion mirrors the symmetry of the inclusion. This represents the main properties of their elastic fields, including the long- and near-field decay. If the inclusion is symmetric with respect to a given axes, the fields will decay with 1 / r 2 in the far field and 1 / r 4 in the near field. If symmetry along that direction is lost, as is expected in most real inclusions, the decay rate progresses with 1 / r 2 but the near field with 1 / r 3 .

Verification Of ballistic machine performance against load and capacity at TPST Samtaku Jimbaran Bali

Waste is the result of a shift in people's consumption habits that are not proportional to the level of their activity. Waste has no use value because it is dirty and smelly, but if it can be processed properly, it can become something valuable and boost the use value of society. Every day, 4,281 tons of waste are created on the island of Bali, according to waste data. Only 52 percent of the waste has been managed, while the rest has been controlled. This ballistic machine that can plan 10 tons per hour is already used in Jimbaran, Bali. The shaft in the study is 2350 mm in diameter and has three parts: screw conveyor input, cutting blades and supports, and screw conveyor outlets. The axial force of the screw conveyor is 513,685 N with a threaded knife cutting force of 1; 73,138 N, thread 2; 76.59 N, thread 3; 75.28 N, thread 4; 73.64 N, thread 5; 71.64 N, thread 6; 69.41N, and thread 7; 66.83 N. Highest moment load on the horizontal part is at x = 2200 mm and the vertical part is at x = 1220 mm in the calculation of the bending moment of 107,099 N/mm2. The engine ballistic produces 16.9 horsepower. The capacity of the machine is 281.7 kg of garbage, and it can produce 1.46 tons per hour after being confirmed in one hour.

Analysis of Comfort during Transfer by a Dual-Arm Care Robot Based on Human Body Pressure and Surface Electromyographic Signals.

In-home elderly care faces a crucial challenge regarding mobility among essential assistive devices, for which dual-arm care robots present a viable solution. However, ensuring human comfort in human-robot interactions necessitate quantifiable standards. Currently, the field lacks accurate biomechanical model solutions and objective comfort evaluation. In response to this need, this study proposes a method for solving human-robot statics models based on real-time pressure and position information. Employing the Optitrack motion capture system and Tekscan pressure sensors, we collect real-time positional and pressure data. This information is then incorporated into our human-robot statics model, facilitating the instantaneous calculation of forces and moments within the human body's sagittal plane. Building on this, comprehensive research literature review and meticulous questionnaire surveys are conducted to establish a comprehensive comfort evaluation function. To validate this function, experiments are performed to enable real-time assessment of comfort levels experienced during the process of transferring the human body. Additionally, the Noraxon surface electromyography (sEMG) sensors are utilized to capture real-time sEMG signals from the erector spinae, adductor muscles and quadratus lumborum, thereby providing objective validation for the comfort evaluation function. The experimental findings demonstrate that the proposed methodology for evaluating comfort achieves an accuracy rate of 85.1%.

Exponentially Correlated Hylleraas–Configuration Interaction Studies of Atomic Systems. III. Upper and Lower Bounds to He-Sequence Oscillator Strengths for the Resonance 1S→1P Transition

The exponentially correlated Hylleraas–configuration interaction method (E-Hy-CI) is a generalization of the Hylleraas–configuration interaction method (Hy-CI) in which the single rij of an Hy-CI wave function is generalized to a form of the generic type rijνije−ωijrij. This work continues the exploration, begun in the first two papers in this series (on the helium atom and on ground and excited S states of Li II), of whether wave functions containing both linear and exponential rij factors converge more rapidly than either one alone. In the present study, we examined not only 1s2 1S states but 1s2p 1P states for the He I, Li II, Be III, C V and O VII members of the He isoelectronic sequence as well. All 1P energies except He I are better than previous results. The wave functions obtained were used to calculate oscillator strengths, including upper and lower bounds, for the He-sequence lowest (resonance) 1S→1P transition. Interpolation techniques were used to make a graphical study of the oscillator strength behavior along the isoelectronic sequence. Comparisons were made with previous experimental and theoretical results. The results of this study are oscillator strengths for the 1s2 1S→ 1s2p1P He isoelectronic sequence with rigorous non-relativistic quantum mechanical upper and lower bounds of (0.001–0.003)% and probable precision ≤ 0.0000003, and were obtained by extending the previously developed E-Hy-CI formalism to include the calculation of transition moments (oscillator strengths).

A dynamic model considering the time-varying friction moment of a flexible rotor system

PurposeBearing friction moments are important factors that affect the vibrations of rotor systems. The bearing friction moments are related to the dimension parameters, lubrication conditions and manufacturing errors of support bearings. This work studies the effects of the bearing friction moments on the vibrations of rotor systems.Design/methodology/approachThe rotor is separated into several shaft elements for formulating a flexible rotor. The time-varying friction moment (TFM) is affected by the time-varying contact loads. The vibrations of FRS from the TFM and Palmgren's friction moment (PFM) calculation methods are compared. Moreover, the effects of the rotor offset and radial clearance on the frequency-amplitude characteristics of FRS are studied.FindingsThe TFM method is more consistent with the actual operation mechanisms. The rotor offset and radial clearance can significantly affect the nonlinear vibrations of FRS. This work provides a new reference and research method for the vibration analysis of rotor systems considering the friction effects.Originality/valueThe elastohydrodynamic lubrication (EHL), elastic hysteresis and differential sliding are considered. A flexible rotor system (FRS) dynamic model considering the TFM is proposed. The vibrations of FRS from the TFM calculation method and empirical calculation formula are compared. The effects of the rotor offset and radial clearance on the frequency–amplitude characteristics of FRS are studied.

From Centrosymmetry to Noncentrosymmetry: Precise Structural Regulation and Characterization on ZnHPO3·2H2O Polymorphs.

Polymorphs of ZnHPO3·2H2O with centrosymmetry (Cmcm) and noncentrosymmetry (C2) structures were prepared by modified solution evaporation and seed-crystal-induced secondary nucleation methods. In Cmcm-ZnHPO3·2H2O, the zinc atoms are only octahedrally coordinated, while in C2-ZnHPO3·2H2O, they feature both tetrahedral and octahedral coordination. As a result, Cmcm-ZnHPO3·2H2O features a 2D layered structure with lattice water molecules located in the interlayer space, while C2-ZnHPO3·2H2O features a 3D electroneutral framework of tfa topology connected by Zn(1)O4, Zn(2)O6, and HPO3 units. The UV-visible diffuse reflectance spectra associated with Tauc's analyses give a direct bandgap of 4.24 and 4.33 eV for Cmcm-ZnHPO3·2H2O and C2-ZnHPO3·2H2O, respectively. Moreover, C2-ZnHPO3·2H2O exhibits a weak second harmonic generation (SHG) response and a moderate birefringence for phase matching, indicating its potential as a nonlinear optical material. Detailed dipole moment calculation and analysis confirmed that the SHG response mainly derived from the HPO3 pseudo-tetrahedra.

Parameter analysis and design on socket CFST column-cap beam joint with UHPC grouted connection

The excellent mechanical properties of concrete-filled steel tube (CFST) make it a competitive alternative to column-cap/foundation cap socket connections in accelerated bridge construction (ABC). To investigate more research parameters and facilitate the seismic design of socket CFST column joints, a detailed numerical analysis model of socket column-cap beam joint was established and verified by experimental data, and the bearing capacity and failure modes of socket joints under the dimensions of the CFST parts and their material properties were investigated as well. It is found that the size of steel tube, the strength of steel tube, the socket depth of CFST, and the type of forming hole have significant effects on the strength and failure modes of column to cap beam socket joints. This study also proposed a moment calculation method for socket joints that can accurately predicts the bearing capacity under different failure modes. Finally, a design process was developed to facilitate the widespread application of this socket CFST column-cap beam joint with Ultra High-Performance Concrete (UHPC) grouted connection.

White blood cell automatic classification using deep learning and optimized quaternion hybrid moments

The structural characteristics of white blood cells (WBCs) can provide important information about human health status. For this reason, over the past four decades, researchers have sought ways to automate the classification and morphological analysis of white blood cells. In the present study, we propose a new method to classify white blood cells into four types: neutrophils, lymphocytes, monocytes, and eosinophils by combining the hybrid discrete moment quaternion approach with deep learning. The proposed classification method is generally divided into two main phases: the first one is called the preprocessing phase, which is devoted to the computation of the image moments to be classified using a new quaternion Meixner-Charlier hybrid moment that is characterized by the following parameters α,β,andφ. In addition, the grey wolf optimization algorithm is used to guarantee high classification accuracy by optimizing the local parameters of the new quaternion Meixner-Charlier hybrid moments. The classification phase, which is the second phase of our proposed convolutional neural network model, is dedicated to introducing image moments. We present various graphical measurements, including receiver operating characteristics, precision-recall curves, and a confusion matrix. To demonstrate the effectiveness of our classification method, we also employ numerical measures such as the F1 score, loss, and accuracy. Our results indicate that the cell types of neutrophils were determined with a 98.53% accuracy rate, lymphocytes with a 98.16% accuracy rate, monocytes with a 97.43% accuracy rate, and eosinophils with a 97.43% accuracy rate.

Study of Magnetic, Optical, Electronic and Thermodynamic Effects in Thallium Rare Earth Disulphides (TlRES2, RE= Tb- Er)

In the present research work, we have investigated density of electronic states, electronic band structure, magnetic structure, optical spectra and temperature dependent thermodynamic characteristics of thallium rare earth sulphides, TlRES2 (RE: Tb-Er) using FP-LAPW method and PBE-GGA exchange correlation within DFT. The electronic structure pointed out that TlRES2 compounds show half metallic character. The magnetic moment and spin polarization calculations prove that TlRES2 are fully spin polarized compounds with ferromagnetic nature. Optical spectra show that intraband transitions occur in infrared (IR) regime due to half metallic character of TlRES2 and behave as opaque in ultraviolet (UV) region. High refractive index in IR regime also show metallic character and high peak in UV regime show slow propagation of light in UV regime. The reflection coefficient is found maximum (~50–60%) in UV regime. Greater energy loss has been seen on the higher energy side, which corresponds to the stimulation of plasmons by electrons moving through the compounds. Plasma resonances lead to the frequent peaks at ~ 6.0 eV, 11.0 eV, and 12.0 eV. According to calculations made using the quasi-harmonic Debye model, TlRES2 compounds are dimensionally less stable (i.e., much hard), have poor thermal conductivity, and experience faster-than-average disorder with increasing the temperature.