Cross Section Distribution Research Articles

Direct strength method for cold-formed steel beams with non-uniform temperatures

This paper presents the results of finite-element simulations leading to the development of a design method using the direct strength method (DSM) for transversely loaded thin-walled steel beams prone to local and distortional buckling failures at elevated temperatures. The systematic and extensive numerical parametric study covers different dimensions of thin-walled steel sections, different temperature distributions in the steel cross-section, different steel grades and different load ratios. The main findings are that DSM is a suitable method for thin-walled steel members with non-uniform elevated temperature distributions in the cross-section. Based on using the plastic moment capacity of the cross-section at elevated temperatures, the DSM equations in the existing specification by the American Iron and Steel Institute, as published in 2016, are sufficiently accurate for local buckling. For distortional buckling, a set of new DSM equations is proposed. The proposed DSM equations are then used to derive partial safety factors for structural resistance for conditional probabilities of structural failure of 0.1, 0.01 and 0.001 after flashover.

Особенности формирования структуры проволоки из аустенитно-мартенситной трип-стали ВНС9-Ш при волочении

Structural-phase transformations in various sections of austenitic wire rod made of martensitic trip-steel VNS9-Sh (23Kh15N6AM3-Sh) at various stages of cold drawing are discussed. It was found that the structure of the near-surface layers of the wire with a diameter of 0.36 mm is completely austenitic. Based on the results of computer simulation of the stress distribution in the wire cross section, an assumption was made about the nature of the formation of such a structure.

Research on Nonlinearity in In situ Calibration of Permanent Magnet Sodium Flowmeter Without Bluff Body

The permanent magnet sodium flowmeter (PMSF) without the bluff body installed on the large-diameter pipe in the fast reactors to measure the sodium coolant flow rate has to be calibrated in situ owing to the degradation of the magnetic field. Since the length of the magnetic field of the PMSF is limited in practical engineering applications, the characteristic between the cross correlation flow rate (CCFR) and the standard flow rate is nonlinear in in situ calibration based on the cross correlation method. Moreover, the nonlinear characteristic has a large repeatability error, which is difficult to apply to in situ calibration. In order to realize the in situ calibration, an “M-type” mean velocity profile in the pipe is obtained by analyzing the influence of the magnetic field on the fluid field. The distribution of the CCFR of the signal at each frequency is analyzed by using the phase-frequency characteristic of the cross-power spectral density (CPSD) of the two signals, and a physical model of the turbulence distribution in the pipe cross section is obtained combining with the “M-type” mean velocity profile. A nonlinearity correction method based on signal frequency band selection is proposed according to the physical model. The in situ calibration experiments of DN150 PMSF without the bluff body are carried out at the sodium temperatures of 400 °C. The signals within 11–20 and 18–35 Hz are used to calculate the CCFR for correcting the nonlinear characteristic, and sodium flow rate measurement accuracy is ±3.0%.

An Energy Spectrum Algorithm for Wind Direction Retrieval From X-Band Marine Radar Image Sequences

In this study, an energy spectrum (ES) algorithm is proposed to retrieve wind direction from X -band marine radar image sequences. This algorithm is based on utilizing the occlusion area zero-pixel percentage to distinguish rain-free and rain-contaminated radar data. And then the rain-contaminated images are detected and discarded. The effect of radar radial attenuation in radar image sequences is modified by the piecewise fitting technique. Wind direction is determined from rain-free and radial correction data, based on the ES of small-scale wind streaks. The ES of small-scale wind streaks is obtained by establishing an ES scale separation filter. Based on the wind streak characteristics, a 2-D fast Fourier transform is used to obtain the ES of radar images. The wind streak characteristics are derived from the distribution of the azimuth normalization radar cross section. The proposed algorithm is tested using data collected from X -band radar images and in situ anemometer data from the coast of the East China Sea. Compared with the anemometer data, after using the proposed algorithm, the root-mean-square difference for wind direction is 12.13°, which is an acceptable result for engineering application.

Impact of thermal renovation on selected characteristics of partition walls and the consumption of heat energy

Renovation of multi-family residentials, including mainly thermal renovation, which includes adding thermal insulation, contributes to the improvement of living conditions. Above all, it reduces the operating costs of renovated buildings by reducing the consumption of heat energy for central heating. This article discusses the impact of light wet thermal renovation on the temperature distribution in the vertical cross-section of the partition wall and the calculation value of the temperature on the inner surface of the partition wall, as well as on the reduction of thermal energy consumption in buildings. The subject of the research was residentials erected in the large-panel, large-block, and traditional technology between 1984 and 1994, managed by Łomża Housing Cooperative (ŁSM).

H1jet, a fast program to compute transverse momentum distributions

We present H1jet, a fast code that computes the total cross section and differential distribution in the transverse momentum of a colour singlet. In its current version, the program implements only leading-order 2rightarrow 1 and 2rightarrow 2 processes, but could be extended to higher orders. We discuss the processes implemented in H1jet, give detailed instructions on how to implement new processes, and perform comparisons to existing codes. This tool, mainly designed for theorists, can be fruitfully used to assess deviations of selected new physics models from the Standard Model behaviour, as well as to quickly obtain distributions of relevance for Standard Model phenomenology.

Non-monotonic potential description of the cross-section, vector and tensor analyzing powers of the 6Li+12C elastic scattering at 30 and 50 MeV†

This work illustrates, for the first time, the analysis of tensor analyzing powers (T 20, T 21, T 22) along with the differential cross-section (CS) and the vector analyzing power iT 11 for the 6Li+12C elastic scattering at 30 and 50 MeVwithin the framework of an optical model (OM) using microscopic shallow non-monotonic (NM) potentials. The NM potential is generated from the energy density functional formalism (EDF) [Brueckner et al., Phys. Rev., 168 (1968) 1184] using a realistic two-nucleon interaction incorporating Pauli Exclusion principle. The shallow NM potential can describe the experimental angular distributions of CS and analyzing powers of the elastic scattering data. The OM analysis of the data at this energy does not indicate their sensitivity on the nuclear matter incompressibility K.

Social Choice in Large Populations with Single-Peaked Preferences

Anonymous social choice function for a large atomless population maps cross-section distributions of preferences into outcomes. Because any one individual is too insignificant to a¤ect these distributions, every anonymous social choice function is individually strategy-proof. However, not every anonymous social choice function is group strategy-proof. If the set of outcomes is linearly ordered and participants have single-peaked preferences, an anonymous social choice function is group strategy-proof if and only if it can be implemented by a mechanism involving binary votes between neighbouring outcomes with nondecreasing thresholds for moving higher up. Such a mechanism can be interpreted as a version of Moulin's (1980) generalized median-voter mechanism for a large population.

A conformal symplectic multi-resolution time-domain method with ADE-PML

In this paper, the conformal finite-difference time-domain (CFDTD) technique and the concept of effective dielectric constant are applied to symplectic multi-resolution time-domain (SMRTD) algorithm based on Daubechies scaling functions, resulting in a conformal SMRTD (C-SMRTD) method. Moreover, a novel implementation of perfect matched layer with auxiliary differential equation (ADE-PML) is presented for the SMRTD method. Numerical results of the radar cross section (RCS) of a dielectric sphere verify the effectiveness of the C-SMRTD method, which shows good agreement with the results derived by analytical methods. It is also shown that the accuracy of the C-SMRTD method has been significantly improved compared with the MRTD method with step approximation, and the proposed method has an advantage over CFDTD at saving the CPU time and memory. Furthermore, a vault-top tunnel model is established with the proposed method, and the characteristic of the field cross-section distribution of the electromagnetic pulse (EMP) propagation in the tunnel model is also presented and discussed.

Stochastic Earnings Growth and Equilibrium Wealth Distributions

The cross-section distribution of U.S. wealth is more skewed than the distribution of labor earnings. Stachurski and Toda (2019) explain how plain vanilla Bewley-Aiyagari-Huggett (BAH) models with infinitely lived agents can't generate that pattern because an equilibrium risk-free rate is lower than the time rate of preference and each person's wealth process is stationary. We provide two modifications of a BAH model that generate this pattern: (1) overlapping generations of agents who have low wealth at birth and pass through N life-stage transitions of stochastic lengths, and (2) labor-earnings processes that exhibit stochastic growth. With only a few parameters such a model can well approximate mappings from the Lorenz curve and Gini coefficient for cross-sections of labor earnings to their counterparts for cross sections of wealth. Three forces amplify inequality in wealth relative to inequality in labor-earnings: stochastic life-stage transitions; a precautionary savings motive for high wage earners that is especially strong after they receive positive permanent earnings shocks; and an energetic life-cycle saving motive for agents who have low wealth at birth. An equilibrium risk-free interest rate that exceeds a time preference rate fosters a fat-tailed wealth distribution. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

Influence of hydrogen on softened heat-affected zones during in-situ slow strain rate testing in advanced high-strength steel welds

Hydrogen stress cracking (HSC) of weldments should be evaluated as it occurs under environmental stress. This study investigated HSC reactions with regard to microstructures and hardness distribution in the transverse cross sections of welds deposited on an advanced high-strength steel through in-situ slow-strain rate testing (SSRT). SSRT in a hydrogen-free environment led to the fracture of the base metal, although a narrow and softened heat-affected zone (HAZ) was observed. However, during in-situ hydrogen charging SSRT, stress triaxiality increased in the softened inter-critical HAZ due to hydrogen trapped, and premature rupture was initiated from hydrogen-promoted voids with enhanced plasticity.

ТЕПЛОГИДРАВЛИЧЕСКИЕ ИССЛЕДОВАНИЯ ВЫСОКОТЕМПЕРАТУРНОЙ ЯЭУ ДЛЯ ПРОИЗВОДСТВА ВОДОРОДА И ДРУГИХ ТЕХНОЛОГИЧЕСКИХ ПРИЛОЖЕНИЙ

An important problem determining the development of clean energy is the involvement of hydrogen in the fuel cycle. At present, the main method of hydrogen production is steam methane conversion. In the long term, large-scale hydrogen production, this method is not viable due to the consumption of non-renewable resources and the emission of greenhouse gases. Alternative methods of hydrogen production by water splitting methods using thermochemical or electrolysis processes require a high-temperature heat source. Nuclear reactors can serve as the most widely used high-temperature heat sources. The performed neutron-physical and thermophysical studies have shown that there is a fundamental possibility to provide the required parameters of a high-temperature (900-950 °C) with a 600 MW (thermal) fast neutron reactor with a sodium coolant for hydrogen production. It’s possible on the basis of one of the thermochemical cycles or high-temperature electrolysis with a high coefficient of thermal utilization of energy. It is shown that the temperature regime of core fuel elements is determined by a large number of parameters that have a regular and statistical nature. The developed methodology and numerical program allows to take into account, in the fuel assemblies shaped during the campaign, the effect on the temperature distribution of the fuel element cladding and temperature irregularities along the fuel element perimeter in the interchannel exchange fuel assembly, the random distribution of channel cross-sections and the heat generation of fuel elements using the Monte Carlo method, also other factors. For various reactor operating regimes, zones with stable temperature stratification with large gradients and temperature fluctuations have been identified. The results obtained make it possible to judge the amplitude and frequency characteristics of temperature pulsations in these potentially dangerous areas. The relative small size, the type of coolant, the choice of fissile material and structural materials make it possible to create a reactor with inherent properties that ensure increased nuclear and radiation safety.

Composite helical spring with skin‐core structure: Structural design and compression property evaluation

AbstractThe helical spring is an essential mechanical component of automobile and machinery and has been widely used in industrial application. The weight reduction is the requirement of current material design and also the research trend for material development. In this study, a novel composite helical spring with “skin‐core” structure was designed and fabricated with an integrated formation process based on the vacuum‐assisted resin infusion technology. Based on the different function of skin and core, the skin structure was weft knitting tube made of aramid and ultra‐high molecular weight polyethylene fiber, and the core structure was unidirectional carbon fiber. By selecting material for knitting tube and adjusting the volume content of carbon fiber core, the static and fatigue compression properties of composite helical spring were investigated. It has been found that the spring torsion and bending performance can be improved by wrapping the core with the knitting tube as the spring wire. Moreover, the finite element method was applied to further analyze the stress evolution of the “skin‐core” composite helical spring during compression and fatigue. The results of compression test and simulation show that the spring stiffness can be effectively improved by using knitting tube and increasing the content of carbon fiber. The stress of the spring cross section is concentrated in the internal radial region of 180°, and the distribution of the corresponding cross sections is relatively uniform. The “skin‐core” structure with aramid knitting tube as the outer skin and carbon fiber as the spring core significantly improves the load‐carrying capacity and stability of the composite spring. The proposed lightweight helical composite could provide a replacement strategy of existing metal or unidirectional filament reinforced springs used in the engineering applications.

Using unitarist, pluralist, and radical frames to map the cross-section distribution of employment relations across workplaces: A four-country empirical investigation of patterns and determinants

The frames of reference model developed by Fox, and extended by a number of other authors, is arguably the central paradigm framework in the employment/industrial relations field. Despite its importance and popularity, use of frames of reference to structure empirical analysis and develop hypotheses is relatively rare and, to the best of our knowledge, the framework and its key constructs and principles have themselves never been empirically examined with data from a representative cross-section of workplaces using quantitative methods. This article, with the aid of a new four-country (Australia, Canada, UK, and US) survey data set on 7000+ workplaces, initiates this kind of empirical study. The frames of reference distinguish three main types of employment relationships: unitarist, pluralist, radical. We select six attitudinal/behavioral indicators from the data set that distinguish which frame a workplace is in, combine them to form a Relational Quality Index, plot the 7000+ Relational Quality Index observations as four-country frequency distributions, and use different statistical criteria to indicate the relative size of each frame. We next do regression analysis in which the 7000+ workplace Relational Quality Index scores are the dependent variable and construct from the data set 20 frames of reference explanatory variables. As theory predicts, workplaces with stronger common (opposed) interests have better (worse) employer–employee relations.

Investigating Effect of Bearing Length on Tensile Strength of 1045 Steel in Wire Drawing Operation

In this work, effect of bearing length on tensile strength was investigated. The influence of the bearing length is illustrated using two different reduction ratios and wire diameters. According to the results, the increase in strength was observed as the length of the bearing zone increased. However, the long bearing length caused various manufacturing problems during production. Microhardness distributions in wire cross section, on the other hand, increased as the length of bearing increased. The main reason for the increase of microhardness is the deformation hardening caused by the high friction force obtained by increasing the bearing length.

Mechanisms of Modulation Formation in Elastic Diffraction Scattering of Charged Particles

In this work, the authors describe experimental data on the angular distributions of alpha particles on light alpha-cluster nuclei. The angular distributions of elastic scattering of alpha particles are analyzed under the assumption of complete absorption inside the sphere of the cluster structure and the sphere of the interaction core. These assumptions made it possible to decompose the scattering amplitude into components—scattering on the nucleus itself and on different cluster structures. The calculations result in the following. The amplitude for describing diffraction elastic scattering by 4n ± 1 light nuclei in the framework of the theory of diffraction scattering is a superposition of wave functions in the scattering approximation on a completely black core and on its absolutely black substructures. The nucleon association modes, as well as the scattering modes on the correlated motion of nucleons and spatially separated nucleons, make a significant contribution to the total scattering amplitude. This manifests itself as an increase in angular distributions due to the interference of modes of various cluster structures and nucleons. Owing to these effects, not only an uneven rise in the angular distributions of differential cross sections over the Rutherford section is possible, but also a rise at rear angles.

Study of the scattering of 15C at energies around the Coulomb barrier

The neutron rich carbon isotope 15C is the only known case of an almost “pure” 2s1/2 single-neutron halo ground state configuration. At collision energies around the Coulomb barrier the reaction dynamics is expected to be dominated by single neutron transfer and breakup. To investigate these effects, we have measured the scattering of 15C with a 208Pb target at 65 MeV at the HIE-ISOLDE facility in CERN (Geneva, Switzerland). The preliminary data demonstrates the presence of a strong long-range absorption pattern in the angular distribution of the elastic cross section. The results are discussed in the framework of Optical Model calculations.

Numerical simulation of creep behaviour of flexible riser inner liner

The creep behaviour of an inner liner, one of the reasons for carcass tearing, may affect the structural integrity of flexible risers. This has been previously discussed without conclusive results owing to complex structure and time-dependent material properties. The present paper proposes a numerical model for predicting creep responses by means of the finite element method. In this model, series coefficient is used to characterise the viscoelastic properties of material. Consequently, the influence of geometric parameters such as span of the carcass layer and thickness of the inner layer on the deformation is observed. Moreover, a threedimensional model assembling the carcass and inner liner was established for mechanical analysis, during which the viscoelasticity of inner liner and the internal friction of the carcass are considered, after which the stress and strain distribution on each layer under the combined external pressure and axial tensile force generated by the inner liner are obtained. Additionally, the effect of external pressures on the stress distribution of the carcass cross-section was found through sensitivity analysis.

MyoSight\u2014semi-automated image analysis of skeletal muscle cross sections

BackgroundManual analysis of cross-sectional area, fiber-type distribution, and total and centralized nuclei in skeletal muscle cross sections is tedious and time consuming, necessitating an accurate, automated method of analysis. While several excellent programs are available, our analyses of skeletal muscle disease models suggest the need for additional features and flexibility to adequately describe disease pathology. We introduce a new semi-automated analysis program, MyoSight, which is designed to facilitate image analysis of skeletal muscle cross sections and provide additional flexibility in the analyses.ResultsWe describe staining and imaging methods that generate high-quality images of immunofluorescent-labelled cross sections from mouse skeletal muscle. Using these methods, we can analyze up to 5 different fluorophores in a single image, allowing simultaneous analyses of perinuclei, central nuclei, fiber size, and fiber-type distribution. MyoSight displays high reproducibility among users, and the data generated are in close agreement with data obtained from manual analyses of cross-sectional area (CSA), fiber number, fiber-type distribution, and number and localization of myonuclei. Furthermore, MyoSight clearly delineates changes in these parameters in muscle sections from a mouse model of Duchenne muscular dystrophy (mdx).ConclusionsMyoSight is a new program based on an algorithm that can be optimized by the user to obtain highly accurate fiber size, fiber-type identification, and perinuclei and central nuclei per fiber measurements. MyoSight combines features available separately in other programs, is user friendly, and provides visual outputs that allow the user to confirm the accuracy of the analyses and correct any inaccuracies. We present MyoSight as a new program to facilitate the analyses of fiber type and CSA changes arising from injury, disease, exercise, and therapeutic interventions.

Effect of inertial migration of particles on flow transitions of a suspension Taylor-Couette flow

Uniformly distributed particles in inertial flows migrate across the streamlines to form nonuniform distributions in the flow cross sections. Here, an experimental study of the influence of inertial migration of particles on flow transitions of a suspension in Taylor-Couette geometry is presented. It is shown that, relative to uniform concentration, the particle distribution following inertial migration either stabilizes or destabilizes the flow depending on the underlying flow structure and flow Reynolds number.