Element Mass Research Articles

Combined hemisphere-cylinder shaped-charge liner optimization for high-velocity metal fragments formation in anti-meteoroid resistance tests

Due to their capability to form high velocity elements, explosive launching devices are used for testing objects of rocket and space technology on anti-meteoric resistance. These devices include shaped charges with a combined hemisphere-cylinder liner. Currently used shaped charges with a hemisphere-cylinder liner can produce compact steel elements with velocities of 6 km/s. Based on numerical simulation in the framework of the two-dimensional axisymmetric problem of continuum mechanics, the possibilities of increasing the velocity of compact metal elements formed by shaped charges with a combined hemisphere-cylinder liner up to 9 … 10 km/s are considered. Simulation has been performed for a 100 mm diameter shaped charge with a copper liner. The stated goal has been achieved by giving the jet-forming hemispherical part of the liner a degressive (decreasing from the top to the base) thickness with a change in its shape from hemispherical to semi-ellipsoid. As a result of calculations, liners geometric parameters have been selected to form compact elements of maximum possible mass with velocities in the range from 5 to 9.5 km/s. For an element with a velocity of about 9.5 km/s, the mass was about 5 g.

Galaxy And Mass Assembly (GAMA): the interplay between galaxy mass, SFR, and heavy element abundance in paired galaxy sets

ABSTRACT We study the star formation rate (SFR), stellar mass (M⋆), and the gas metallicity (Z) for 4636 galaxy pairs using the Galaxy And Mass Assembly (GAMA) survey. Our galaxy pairs lie in a redshift range of 0 < z < 0.35, mass range of 7.5 < log(M⋆/M⊙) < 11.5 and ΔV < 1000 km s−1. We explore variations in SFR and Z from three point of views: multiplicity, pair separation, and dynamics. We define multiplicity as the number of galaxies paired with a single galaxy, and analyzed for the first time variations in SFR and Z for both, single pairs and pairs with higher multiplicity. For the latter, we find SFR enhancements from 0.025–0.15 dex, that would shift the M–SFR relation of single pairs by 27${{\ \rm per\ cent}}$ to higher SFRs. The effect of Z, on the other hand, is of only 4${{\ \rm per\ cent}}$. We analyse the most and least massive galaxy of major/minor pairs as a function of the pair separation. We define major pairs those with mass ratios of 0.5 < M1/M2 < 2, while pairs with more discrepant mass ratios are classified as minor pairs. We find SFR enhancements of up to two and four times with respect to their control sample, for major and minor pairs. For the case of Z, we find decrements of up to 0.08 dex for the closest pairs. When we focus on dynamics, Z enhancements are found for minor pairs with high-velocity dispersion $(\sigma _p \gt 250 \,\, \mathrm{km\, s ^{-1}})$ and high multiplicity.

Incorporation of U, Pb and Rare Earth Elements in Calcite through Crystallisation from Amorphous Calcium Carbonate: Simple Preparation of Reference Materials for Microanalysis

Uncertainty for elemental and isotopic measurements in calcite by LA‐ICP‐MS is largely controlled by the homogeneity of the reference materials (RMs) used for calibration and validation. In order to produce calcite RMs with homogeneous elemental and isotopic compositions, we incorporated elements including U, Pb and rare earth elements into calcite through heat‐ and pressure‐induced crystallisation from amorphous calcium carbonate that was precipitated from element‐doped reagent solution. X‐ray absorption spectra showed that U was present as U(VI) in the synthesised calcite, probably with a different local structure from that of aqueous uranyl ions. The uptake rate of U by our calcite was higher in comparison with synthetic calcite of previous studies. Variations of element mass fractions in the calcite were better than 12% 2RSD, mostly within 7%. The 207Pb/206Pb ratio in the calcite showed < 1% variations, while the 238U/206Pb ratio showed 3–24% variations depending on element mass fractions. Using the synthetic calcite as primary RMs, we could date a natural calcite RM, WC‐1, with analytical uncertainty as low as < 3%. The method presented can be useful to produce calcite with controlled and homogeneous element mass fractions and is a promising alternative to natural calcite RMs for U‐Pb geochronology.

Transmission error investigation of gearbox using rigid-flexible coupling dynamic model: Theoretical analysis and experiments

The transmission error (TE) is one of the most important excitations of gearbox vibration. In previous studies, simplified models composed of meshing gears alone were built to analyze the TE. However, the flexibility of other system components was ignored. In this study, a system-level TE investigation of gearbox is carried out by proposing a rigid-flexible coupling dynamic model. In this model, the meshing pair, flexible shaft, and bearing are established by a lumped mass element, beam element, and spring element, respectively. Housing flexibility is introduced into the analysis through model condensation, and a modal test is launched to verify its effectiveness. Moreover, a TE test rig is set up to compare the theoretical and experimental results. These results show that the TE increases with increasing load. Furthermore, the TE decreases when the housing flexibility is considered, especially when the gearbox is running at higher speed and when the housing is a thin-walled structure. Appropriately decreasing the stiffness of the housing can decrease the TE. Additionally, increasing the inner radius of hollow shaft simultaneously reduces the shaft weight and decreases the system TE.

Simplified multimode control of seismic response of high-rise chimneys using distributed tuned mass inerter systems (TMIS)

The industrial chimney is one of the important components used in industrial processes. The tuned mass damper was introduced in previous studies to improve its reliability for resisting earthquakes. However, a large additional mass is generally required for applying a tuned mass damper in a chimney, which may be inappropriate owing to the additional moment action. In this study, the tuned mass inerter system (TMIS) is adopted as an ungrounded lightweight passive control device for the seismic response mitigation of high-rise chimneys. The ungrounded TMIS consists of a tuned mass element and a parallel-connected tuning spring and inerter subsystem. Considering that the influence of high modes on the responses of a high-rise chimney may not be neglected, distributed TMISs (d-TMISs) are proposed for installation on the chimney for multimode control of seismic response. A strategy to optimize d-TMISs for multimode control of high-rise chimneys is developed. A typical numerical chimney model is established to illustrate the proposed optimal design method. Time history analysis and comparative studies are conducted to verify the optimal multimode control design and the lightweight effect of d-TMISs compared to the traditional tuned mass dampers. The results show that by applying the proposed optimization in d-TMISs, the performance objectives can be achieved and the chimney’s responses involving the high-order modes can be reduced as anticipated. The required weight of d-TMISs is less than that for tuned mass dampers under an identical performance objective. It is observed that the proposed optimal multimode control method is effective and that d-TMISs can achieve the lightweight effect.

A Comparative Study on Various Stages of Level of Details in Advanced 3D Building Construction Using BIM Tools

Building Information Modelling is one of the most emerging technologies that provide productivity, efficiency and compliance in the construction industry. There are various platforms on which the 3D buildings can be created with large viewing capabilities. The current paper concentrates not only on the construction of 3D buildings with extrusions but also compares the various levels of details in two different BIM based 3D softwares namely ESRI City Engine and Revit Architecture. A 3D building object can be represented basically with four LOD levels at each stage of the building construction. The focal point of the current study also reflects the creation of building interiors and their corresponding attribute information to each element of the building. In City Engine software developed by ESRI, CGA codes are modified and customized to enhance the advancement in the building construction such as generation of building mass, segments, Roofs, Facade Creation, and other Architectural elements. These basic blocks of the building are produced by using Rule based pseudo codes in City Engine. The study illustrates a sample building and incorporates these codes to generate the 3D Building and the interiors are designed with more detailed components in Revit software. Hence, BIM is a path that provides effective monitoring, coordination and collaboration in construction field.

Analysis of XMM-Newton Observations of Supernova Remnant W49B and Clues to the Progenitor

Abstract W49B is a supernova remnant (SNR) discovered over 60 yr ago in early radio surveys. It has since been observed over the entire wavelength range, with the X-ray morphology resembling a centrally filled SNR. The nature of its progenitor star is still debated. Applying Smoothed Particle Inference techniques to analyze the X-Ray emission from W49B, we characterize the morphology and abundance distribution over the entire remnant. We also infer the density structure and derive the mass of individual elements present in the plasma. The morphology is consistent with an interaction between the remnant and a dense medium along the eastern edge, and some obstruction toward the west. We find a total mass of 130 M and an estimated ejecta mass of 1.2 M . Comparison of the inferred abundance values and individual element masses with a wide selection of SN models suggests that deflagration-to-detonation (DDT) Type Ia models are the most compatible, with Fe abundance being the major discriminating factor. The general agreement between our abundance measurements and those from previous studies suggests that disagreement between various authors is more likely due to the choice of models used for comparison, rather than the abundance values themselves. While our abundance results lean toward a Type Ia origin, ambiguities in the interpretation of various morphological and spectral characteristics of W49B do not allow us to provide a definitive classification.

Element enrichment/depletion during faulting in shale-rich surface exposures of the 2008 Wenchuan earthquake (Mw 7.9) and implications for coseismic temperature

The coseismic frictional temperature is increasingly recognised as an important factor for the transformation mechanism in shallow crustal faulting. We report changes in the mineralogical and geochemical compositions across the fault zone in the Shaba (SB) exposure of the 2008 Wenchuan earthquake (Mw 7.9), which contained the maximum value of vertical displacement and cut through shale-rich strata by the principal slip surface. Assuming Yb to be an immobile trace element, with respect to those in the adjacent damaged zone and wall rocks, Li, Rb, Cs and most light rare earth elements (LREE) exhibited marked enrichments of 143%, 247%, 475% and >60%, respectively; and a 40% depletion of Sr and <5% depletion of most heavy rare earth elements (HREE) was found, responding to mineralogical transformation such as alteration and dissolution of feldspar and formation of abundant clay minerals. In addition, heterogeneous adsorption of clay minerals could result in fractionation between and within LREE and HREE as well as negative Eu anomalies and positive Ce anomalies. The element enrichment/depletion model of the northern segment of the Yingxiu–Beichuan (YX–BC) fault zone was quite different from the middle/southern segments characterising faults in carbonate and granitic rocks. Through model calculation, the calculated trace element compositions (Li, Rb, Sr, Cs, Ba, La, Sm and Pb) of the fault gouge were obtained at 250 °C, 300 °C and 350 °C, and were produced by frictional heating. By comparing with the observed values, we suggest that high temperatures derived from frictional heating or due to buffering of the slip zone temperature by evaporation of pore water during the earthquake within the principal slip surface in the northern segment of the YX–BC fault zone may not have existed. Mechanical crushing and chemical alteration (not under high-temperature conditions) within the fault zone during the coseismic stage may result in mass removal and element enrichment/depletion. KEY POINTS Mineralogical and geochemical compositions were reported in the Shaba exposure of the 2008 Wenchuan earthquake. Li, Rb, Cs and most LREE exhibited marked enrichments in the fault gouge. Fractionation between and within LREE and HREE, negative Eu anomalies and positive Ce anomalies occur in the fault gouge. High temperatures may not have existed within the principal slip surface of the northern segment of the YX–BC fault zone.

Element Abundances in the Unshocked Ejecta of Cassiopeia A

Abstract We analyze and model the infrared spectrum of the Cassiopeia A supernova remnant with the aim of determining the masses of various elements in the unshocked ejecta. In this way, we complement the survey of the X-ray-emitting ejecta to provide a complete census of the elemental composition of the Cas A ejecta. We calculate photoionization–recombination equilibria to determine the ionization balance of various elements in the ejecta as a function of density using the X-ray and UV emission from the forward and reverse shocks as the ionizing radiation. With the assumption that all emission lines are principally excited at the ejecta density that maximizes their emission, we can convert observed line intensities into element masses. We find that the majority of the ∼3 M ⊙ ejecta have already been through the reverse shock and are seen today in X-rays. A minority, ∼0.47 ± 0.05 M ⊙, with uncertainties quoted here coming from the data fitting procedure only, are still expanding inside the reverse shock and emitting in the infrared. This component is comprised mainly of O, Si, and S, with no Fe readily detectable. Incorporating uncertainties estimated to come from our modeling, we quote M ⊙. We speculate that up to a further 0.07 M ⊙ of Fe may be present in diffuse gas in the inner ejecta, depending on the Fe charge state.

High-order finite beam elements for propagation analyses of arbitrary-shaped one-dimensional waveguides

This paper presents advanced-kinematics beam models to compute the dispersion characteristics of one-dimensional guides. High-order functions are used to interpolate the primary variables above the waveguide cross-section and along its axis. Taylor- and Lagrange-type bi-dimensional expansions are employed to describe the section deformation, while Lagrangian shape functions approximate the displacement field along the propagating direction. According to the Wave Finite Element Method, the stiffness and mass matrices corresponding to various structural theories are post-processed to build the transfer matrix of a representative waveguide portion. The Carrera Unified Formulation is exploited to calculate these matrices.

Wear of the working parts of agricultural tools in the context of the mass of chemical elements introduced into soil during its cultivation

For the manufacture of working parts of agricultural tools operating in soil, various structural materials are used: alloy and low-alloy steels, weld materials for hardfacing, and plates made from cemented-carbide. Manufacturers design new construction solutions to obtain components that are resistant to abrasive wear and impact. These components are subject to wear during soil cultivation, due to which wear products remain in the soil. In this work, the mass of chemical elements remaining in soil from materials used in selected working parts of agricultural tools intended for soil cultivation was estimated. During the operation of the tested parts, it was found that the following elements were introduced into the soil: Al, B, C, Co, Cr, Cu, Fe, Mo, Nb, Ni, P, Pb, S, Si, Ti, V, W and Zr. Iron was introduced into the soil in the highest amount (15.907–222.004 g∙ha-1). Among the chemical elements reaching the soil, there were also elements that may pose a toxicological threat. It was found that the mass of chemical elements introduced into the soil depends on their content in the used structural materials and also on the conditions of cultivation, which determine the wear intensity of the parts.

Three New Geochemical Reference Materials for Mineral Exploration and Environmental Contamination Studies: SdAR‐L2, SdAR‐M2 and SdAR‐H1

The preparation and characterisation of three new sediment‐based reference materials SdAR‐L2 (blended sediment), SdAR‐M2 (metal‐rich sediment) and SdAR‐H1 (metalliferous sediment) described in this paper involved collaboration between the United States Geological Survey (USGS) and International Association of Geoanalysts (IAG). Sediments and soils from six locations in the western United States were mixed according to a USGS‐designed blending programme that calculates the proportions of source materials required to match target mass fractions and minimise the number of elements with mass fractions below instrument detection limits. For selected element mass fractions, NIST SRMs 2709–2711 provided target values. By using this approach, the three reference materials retained a natural mineralogy that is so essential for matching matrix and dissolution characteristics. Geochemical characterisation of these materials was carried out through the IAG GeoPT proficiency testing programme. Three independent rounds of GeoPT testing were used, each providing results from over eighty laboratories. Contributed results were statistically evaluated to produce reference values for over forty elements in each material. Reference and information values as well as mineralogical compositions are presented to establish these samples as reference materials, especially for use in mineral exploration and environmental contamination monitoring studies.

Sound insulation of timber hollow box floors: Collection of laboratory measurement data and trend analysis

The industrialisation of timber buildings has improved strongly in recent years. When long span is required, timber hollow-box floor elements are increasingly used due to their structural performance. The aim of this paper is to assess the acoustic performance of timber hollow-box floors, determine the governing parameters and identify the corresponding trends. We collected results from laboratory measurements covering both airborne and impact sound insulation from four different laboratories covering a wide range of application. Data include the bare floor constructions and their combination with different floating floors including both lightweight solutions and hybrid solution. We performed the analysis focusing on following parameters: element stiffness, element mass per unit area, dynamic stiffness of the resilient layer, cavity filling and floating floor material. We present the collected data both frequency-dependent and as single number quantities. General trends and features are identified in the frequency-dependent diagrams. A further detailed analysis is based on the single number quantities. It includes a general relationship between element mass per unit area and given requirements for R’W + C50-5000 and L’n,w + CI,50-2500. Furthermore, diagrams are presented illustrating the dependence of impact sound insulation numbers on the cavity filling, the dynamic stiffness of the resilient layer and the type of material used for the floating floor. The additional mass in the cavity improves both airborne and impact sound insulation by minimum 10 dB. This, combined with a floating floor, allows the fulfilment of a wide range of requirements.

The Second Wave of Pension Reforms (2009–2019): Transformation of Pension Systems Projection

This article is an extension of the article published in «Outlines of global transformations: politics, economics, law» № 6, 2019 [Zhukova 2019], in which explanation of pension waves formation mechanism, its integration in business-cycles, periodization and detailed analyses of the first wave of pension reforms are provided. In this article based on new macroeconomic and forecasted demographic factors, detected episodes of pension reforms the time frame and the characteristics of the second wave (2009 – 2019) is made, the third wave (since 2020) is predicted. The second wave in size is several years shorter than the first wave. It is characterized by more intensive and numerous pension reforms in the background of a similar number of macroeconomic shocks. The reasons for this are macroeconomic problems, the mass element of macroeconomic shocks connected with economic slowdown, budget deficits growth. The shrinking of the second-pillar pension system and its transformation into private hands become massive in scope. The reduction in the government’s pension obligations is accelerated. The third wave (since 2020) is expected to be the longest and the most intensive. The key characteristic is high probability of acroeconomic shocks connected with all macroeconomic factors sensitive for pension system to all groups of countries, passing the point of tightening of demographic pressures. The thrust of reform is changed to contradictory courses of action. On the one hand state presence, pension system coverage will continue to grow. On the other hand state guarantee (minimum pensions, age and another restrictions on retirement) will continue to decline. The growth of solidarity of public pension systems, of «payments burden» on working people to assure a minimum pensions for older persons, less dependence of the amount of the pension on the total insurance payments made are expected. Funded pensions will become the responsibility of individually insured persons without the financial participation of the State.

Changes in fine root decomposition of primary Pinus koraiensis forest after clear cutting and restoration succession into secondary broad-leaved forest

Fine root decomposition is one of the primary mechanisms by which nutrient uptake and C exchange occur in terrestrial ecosystems, which will be likely affected by forest succession. Herein, we compared the fine root decomposition rates of primary Korean pine forest (PK) and secondary broad-leaved forest (SF) using the litter bag method; then conducted an in-depth analysis of differences in the PK and SF fine root decomposition process. Our results demonstrated that the fine root decomposition in PK was significantly faster than that in SF. In general, the percent (%) mass of the main nutrient elements remaining in SF fine roots was significantly higher than that in PK, indicating that PK can more efficiently return soil nutrients through fine root decomposition. We also found that the succession of PF to SF induced significant alternation of the microbial community composition and decreased activities of soil enzymes. Structural equation modeling further demonstrated that fine root K and lignin were the key substrate-level factors affecting fine root decomposition, while actinomycetes and fungi PLFA biomass change played the most important role among all the functional groups. Finally, we determined that fine root degradation was driven by polyphenol oxidase and acid phosphatase enzymatic activities. This study elucidates the complex interactions between fine root substrate and soil physiochemical properties and demonstrates how they affect fine root decomposition via soil microorganisms. Given that these changes continue over long time scales, the secondary forest will experience increased difficulty return to the original primary Korean pine broad-leaved forest vegetation.

Dynamic performance analysis and parameters perturbation study of inerter–spring–damper suspension for heavy vehicle

Inerter, a new type of mass element, can increase the inertia of motion between two endpoints. In order to study the dynamic inertia effect of inerter–spring–damper suspension for heavy vehicle on ride comfort and road friendliness, the inerter–spring–damper suspension is applied and its mechanism is studied. This paper establishes a half vehicle model of inerter–spring–damper suspension for heavy vehicle. The parameters of inerter–spring–damper suspension for heavy vehicle are optimized by multi-objective genetic algorithm and system simulations are carried out. The parametric influence of different spring stiffness, damping coefficient, inertance, and load on suspension performance is also studied. The simulation results demonstrate that the centroid acceleration and pitch angular acceleration are improved by 24.90% and 23.54%, respectively, and the comprehensive road damage coefficient is reduced by 4.05%. The results illustrate that the inerter–spring–damper suspension can decrease the vertical vibration of vehicle suspension especially in low frequency and reduce the road damage. The analyses of suspension parameters perturbation reveal their different effect laws of the different wheels on vehicle ride comfort and road friendliness, which provide a theoretical basis for setting parameters of inerter–spring–damper suspension.

Major and Trace Elements in Moldavian Orchard Soil and Fruits: Assessment of Anthropogenic Contamination.

The correct assessment of the presence of potentially contaminating elements in soil, as well as in fruits cultivated and harvested from the same places has major importance for both the environment and human health. To address this task, in the case of the Republic of Moldova where the fruit production has a significant contribution to the gross domestic product, the mass fractions of 37 elements (Na, Mg, Al, Ca, Si, K, Mn, Fe, Sc, Ti, V, Cr, Co, Ni, Zn, As, Br, Rb, Sr, Zr, Mo, Cd, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Hf, Ta, W, Th, and U) were determined by instrumental neutron activation analysis in soil collected from four Moldavian orchards. In the case of three types of fruits, grapes, apples, and plums, all of them collected from the same places, only 22 elements (Na, Mg, Cl, K, Ca, Sc, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Rb, Sr, Sb, Cs, Ba, La, Th, and U) were detected. The enrichment factor, contamination factor, geo-accumulation index, as well as pollution load index were calculated to assess the soil contamination. At the same time, the metal uptake from the soil into fruits was estimated by means of transfer factors. Soil samples showed for almost all elements mass fractions closer to the upper continental crust with the exception of a slightly increased content of As, Br, and Sb, but without overpassing the officially defined alarm thresholds. In the case of fruits, the hazard quotients for all elements with the exception of Sb in fruits collected in two orchards were below unity. A subsequent discriminant analysis allowed grouping all fruits according to their type and provenance.

Abaqus implementation of dual peridynamics for brittle fracture

A dual peridynamics (PD) for brittle fracture is implemented in the commercial software Abaqus by means of UEL/VUEL and UMAT/VUMAT subroutines, thereby, the peridynamic finite element method (PDFEM) will come into being. To this end, the concept of the peridynamic node and element is defined, subsequently, the peridynamic element internal force vector and mass matrix for the explicit PDFEM and the peridynamic element stiffness matrix for the implicit PDFEM are derived and constructed for the explicit and the implicit finite element implementation of the dual peridynamics in Abaqus, respectively. Additionally, a dual-based coupling approach is developed to couple the PDFEM and FEM to optimize the computational efficiency and accuracy of the pure PDFEM. Several numerical examples involving the static and dynamic crack propagation are investigated and the satisfactory results show the availability of the PDFEM and the hybrid model between PDFEM and FEM. Moreover, the finite element implementation of peridynamics in Abaqus may pave the way to an increased application of peridynamics to the practical engineering problems.

Strain gradient differential quadrature finite element for moderately thick micro‐plates

SummaryIn this study, we integrate the advantages of differential quadrature method (DQM) and finite element method (FEM) to construct a C1‐type four‐node quadrilateral element with 48 degrees of freedom (DOF) for strain gradient Mindlin micro‐plates. This element is free of shape functions and shear locking. The C1‐continuity requirements of deflection and rotation functions are accomplished by a fourth‐order differential quadrature (DQ)‐based geometric mapping scheme, which facilitates the conversion of the displacement parameters at Gauss‐Lobatto quadrature (GLQ) points into those at element nodes. The appropriate application of DQ rule to non‐rectangular domains is proceeded by the natural‐to‐Cartesian geometric mapping technique. Using GLQ and DQ rules, we discretize the total potential energy functional of a generic micro‐plate element into a function of nodal displacement parameters. Then, we adopt the principle of minimum potential energy to determine element stiffness matrix, mass matrix, and load vector. The efficacy of the present element is validated through several examples associated with the static bending and free vibration problems of rectangular, annular sectorial, and elliptical micro‐plates. Finally, the developed element is applied to study the behavior of freely vibrating moderately thick micro‐plates with irregular shapes. It is shown that our element has better convergence and adaptability than that of Bogner‐Fox‐Schmit (BFS) one, and strain gradient effects can cause a significant increase in vibration frequencies and a certain change in vibration mode shapes.

Three-Axis Theorem in Moment of Inertia Computation

A very important property in the study of rigid body dynamics, moment of inertia describes the resistance of an object to any change in its angular velocity, given a certain amount of torque. Although many novel methods have been developed to simplify its calculation, this paper presents a remarkable theorem in moment of inertia that has never been widely used, the three-axis theorem. The theorem provides an alternative way for moment of inertia computation and better visualization in integrating each infinitesimal constituent mass element of a rigid body. The key idea is to focus on the distance from this infinitesimal mass to the intersection of the three axes, instead of its distance to a certain rotational axis.