Types Of Substructures Research Articles

1H and 13C NMR investigation of conformational and aggregation behavior of sodium N-lauroyl sarcosinate

Complementary experiments with NMR 1H and 13C spectroscopy, proton diffusometry, and relaxometry have been used to investigate the sodium N-lauroyl sarcosinate (SLS) micellar systems in aqueous solutions. The effects of concentration and temperature on molecular conformation, micellar structure, and molecular kinetic in the SLS solutions were studied. Each NMR spectral line of the SLS spectrum splits but there are two variants of the effect: (i) for the head-groups this effect exists in the whole concentration range and it is due to the presence of two conformational isomers, (ii) for the hydrophobic part the splitting of resonance lines is observed in certain concentration range and caused by the existence of two different realizations of micellar aggregates. The concentration of the cis-conformers is a bit higher in a “monomer” (diluted) solution as well as the trans-conformers are more favorable in the micellar state. The relation of cis- and trans-conformer fractions is nearly independent of temperature. The transient concentration range, where different types of micellar sub-structures co-exist, is discovered. Moreover, the SLS solutions are characterized by four kinetic processes with different time scale.

Influence of the Initial State of Samples From Steel 20 on the Structural-Phase Condition to the Stable Zone Localization of Macrodeformation

One of the most important tasks of technical diagnostics and examination of industrial safety is the problem of assessing the residual life of long-running technical devices of hazardous production facilities. The paper presents the results of the study of the structural-phase state in a stable zone of localization of macrostrains, depending on the initial state of samples from steel 20. The samples were investigated without exploitation, after operation without destruction and with destruction. The samples were stretched at the same speed until a stable zone of strain localization appeared, after which the loading was stopped. The connection is established between the processes of localization of macrostrains and the evolution of the substructural state for steel 20. It has been established that the mechanism of localization of macrodeformations is the achievement of critical values of a fragmented substructure, in other words, according to the theory of evolution of substructural transformations, a bifurcation point occurs when the % fragmented substructure prevails. The critical values of dislocation density are established, which lead to a change in the type of dislocation substructure for equipment made of steel 20.

Verification of boundary conditions of numerical modeling of the track substructure thermal regime – influence of the snow cover

The initial part of the paper briefly characterizes a long-term experimental activity at the Department of Railway Engineering and Track Management (DRETM). The research of the DRETM focuses, besides other research activities and specific problems in the field of railway engineering (application of new structures and construction materials in conventional and modernized railway tracks, modernisation and rehabilitation of existing railway tracks for higher speeds, track diagnostics, influence of track operation on noise emissions and design of structural measures, possibility of application of recycled ballast bed material in the track substructure, ballast recycling technologies, ecological assessment of recycled material of the track substructure), on various factors affecting track substructure freezing. In 2012-2017, in the campus of the University of Žilina (UNIZA), an Experimental stand DRETM was built for the research purposes. The experimental stand DRETM consists of 6 types of track substructure placed in an embankment or a cut, in the 1:1 scale. Besides conventional building materials (crushed aggregate), these structures also include various thermal insulation materials (Liapor concrete, Styrodur, foam concrete). A significant part of the paper deals with numerical modeling of the freezing process of track substructure (an embankment with the embedded protective layer of crushed aggregate, fr. 0/31.5 mm) for various boundary conditions (air frost index, average annual air temperature), using SoilVision software. The aim of this research is to identify the thermal insulation effects of different thicknesses of snow cover on the depth of penetration of the zero isotherm into the track substructure (railway track). The paper conclusion specifies the influence of different snow cover thicknesses, or nf factor (factor expressing the dependency between the mean daily air temperature and the temperature on the ballast bed surface) and various climatic conditions (frost indexes and average annual air temperatures), affecting the railway infrastructure, on the resulting depth of freezing of the track substructure (railway track). These outputs will be in the further research used for the design of nomogram for determining the thickness of the protective layer of the frost-susceptible subgrade surface of the track substructure.

The Disk Substructures at High Angular Resolution Project (DSHARP). II. Characteristics of Annular Substructures

Abstract The Disk Substructures at High Angular Resolution Project (DSHARP) used ALMA to map the 1.25 mm continuum of protoplanetary disks at a spatial resolution of ∼5 au. We present a systematic analysis of annular substructures in the 18 single-disk systems targeted in this survey. No dominant architecture emerges from this sample; instead, remarkably diverse morphologies are observed. Annular substructures can occur at virtually any radius where millimeter continuum emission is detected and range in widths from a few astronomical units to tens of astronomical units. Intensity ratios between gaps and adjacent rings range from near-unity to just a few percent. In a minority of cases, annular substructures coexist with other types of substructures, including spiral arms (3/18) and crescent-like azimuthal asymmetries (2/18). No clear trend is observed between the positions of the substructures and stellar host properties. In particular, the absence of an obvious association with stellar host luminosity (and hence the disk thermal structure) suggests that substructures do not occur preferentially near major molecular snowlines. Annular substructures like those observed in DSHARP have long been hypothesized to be due to planet–disk interactions. A few disks exhibit characteristics particularly suggestive of this scenario, including substructures in possible mean-motion resonance and “double gap” features reminiscent of hydrodynamical simulations of multiple gaps opened by a planet in a low-viscosity disk.

Regular Substructures in the Rich Open Galaxy Clusters

We present the results of study the 2D distribution of galaxies in 254 rich open galaxy clusters. The clusters have no concentration to the center, so all kinds of substructures are clearly seen. Regular linear substructures in galaxy clusters were described in Rood & Sastry scheme of morphological types according to positions of 10 brightest galaxies. Another types of regular substructures were missed. Our study fills the lacuna. We have found about 25% of clusters in our data set having four kinds of regular substructures, beyond founded before linear ones. New kinds of regular substructures are: crossing and divaricating filaments or X and Y-type peculiarities, as well as curved strips and short dense chains. We suppose the distribution of dark matter in founded galaxy clusters with substructures have corresponded regular peculiarities. Hot gas distribution in these clusters must be observed distorted X-ray halo. We suppose also the clusters will evolve in the different ways.

The development of conceptual options to the construction of ice-resistant floating wind power plants

This paper addresses the conceptual engineering solutions for a Marine Floating Power Plant which uses the Wind energy and is designed to supply electrical power to Russian Arctic coastal and island territory. The analysis of different types current Wind Turbines (WT) made a basis for a construction configuration for sea based Arctic Marine Floating Wind Power Plants and helped define the main wind, wave and ice loads influencing Marine Floating Wind Power Plants in Arctic conditions. Also, different types of Marine Floating Wind Power Plant substructures were analyzed. Numerical modelling of the behavior of the considered conceptual options of Marine Floating Wind Power Plants was carried out. Strength analysis of substructures for Arctic offshore wind power plant options in question has been performed.

Application of Electrical Conductivity Measurements in Material Research and in Solution of Technological Problems

Electrical conductivity depends significantly on a structural state. It can be influenced by chemical composition, content of alloying elements, presence of different types of phases and dislocation substructure as well. Therefore, the relation between electrical conductivity and mechanical properties is very interesting from a material point of view. In combination with structural analyses (metallography, electron microscopy), important information about materials structures and their changes as a function of various factors (deformation, heat treatment) can be obtained. The present paper describes the role of electrical conductivity measurements during an investigation of the effect of technological parameters on the structure and properties of aluminium alloys.

Effect of austenite grain size on acicular ferrite transformation in a HSLA steel

Austenite grain size is well known to have a significant influence on various phase transformations in steels. Although the effects of many thermomechanical processing parameters on acicular ferrite (AF) transformation in HSLA steels have been investigated, little attention has been paid to the influence of austenite grain size. Therefore, in this research, different parameters of solid-solution heat treatment and rough deformation were adopted to generate austenite with different grain sizes and the effects of austenite grain size before deformation on the AF transformation and grain refinement were investigated. It was found that the reduction of prior-austenite grain size (PAGS) from 62.8 μm to 37.0 μm before austenite deformation promotes the AF transformation and simultaneously refines and homogenises the transformed microstructures. A reciprocally increased density of deformation induced dislocations with the reduction of PAGS was proposed to account for these results, which not only increase the nucleation sites of AF but also suppress the lengthening of BF laths. Further reducing PAGS from 37.0 μm to 22.3 μm, the fraction of AF is not increased and the transformed microstructure is not refined. Possible differences in the type, distribution, and density of austenite deformation substructures between austenite with PAGSs of 37.0 μm and 22.3 μm were argued to be responsible for the cease of grain refinement. The relationship between effective grain sizes and the Sv parameter was investigated and an equation relating effective grain sizes with processing parameters was also proposed.

Cross-sectional analysis of the graded microstructure and residual stress distribution in a TiNi alloy treated with low energy high-current pulsed electron beam

A Ti-(55.08wt.%)Ni shape memory alloy (SMA) having a grain size of 30 μm, was subjected to low-energy high-current pulsed electron beam (HCPEB) irradiation with parameters: pulse duration τ = 2−2.5 μs, maximum electron energy 25 keV, energy density ES = 3.8 ± 0.7 J/cm2; beam diameter of ∼ 60 mm, number of pulses n = 32. Microstructure modifications, a value and distribution of residual stress induced by HCPEB treatment were investigated in detail. XRD and cross-sectional TEM/EDS/SAED analysis were used for microstructural characterization of the TiNi samples before and after HCPEB treatment. As a result, the HCPEB-modified TiNi surface layer consists of four successive sublayers differing in phase composition, type of texture and defect substructure. In total, the thickness of the HCPEB-modified TiNi surface layer is, at least, 10 μm. Based on the XRD and nanoindentation data, the dependences of residual stress values on the depth from the irradiated surface in the HCPEB-modified TiNi surface layer were estimated and plotted. The values and sings of the stress components in perpendicular (σI⊥) and parallel (σI||) directions to the TiNi sample surface were calculated: σI⊥ <0, σI||>0. The gradient of residual stress values is preserved in the HCPEB-modified TiNi surface layer: from ∼ 800 MPa (in absolute value) near the irradiation surface to ∼ 220 MPa at a depth of about ∼ 10 μm. The residual stress fields are localized in the near-surface layer I and sublayer III with different type of B2-structure. Their relaxation occurs in the sublayer II by means of the stress-induced В2 → R martensitic transformation.

Cyclic plastic deformation behaviour of a directionally solidified nickel base superalloy at 850 °C: Damage micromechanisms

Dislocation based deformation micromechanisms during low cycle fatigue deformation of nickel base superalloy CM 247 DS LC at 850 °C was investigated by conducting fatigue tests employing constant strain amplitudes for strain ratio (R) values of 0, −1 and carrying out extensive SEM and TEM examinations. Cyclic life of the alloy reduces for all fatigue tests conducted employing R = 0 in comparison with R = −1 owing to sustained mean stress developed during fatigue at R = 0. TEM examinations confirmed that sustained mean stress developed during low strain amplitude fatigue test (Δε/2 = 0.5%) using R = 0 condition prevented slip transfer from γ-channels to γ′-precipitates and resulted in the formation of dislocation substructures such as networks, nodes etc. and also promoted dislocation looping around γ′-precipitates. Lower fatigue life at R = 0 is mainly attributed to the development of these types of substructures, which promotes strain localization in both intra as well intergranular regions. Whereas, in specimen fatigue tested (Δε/2 = 0.5%) using R = −1 condition, shearing of γ′-precipitates by APB coupled dislocation and formation of stacking faults were observed. The formation and nature of stacking faults were analysed using weak beam imaging technique. Stacking fault formed during fatigue tests using R = −1 condition matured to micro-twins when Δε/2 value was increased to 0.8%. The mechanism of formation of these microtwins is discussed in detail. SEM based microstructural and fractographic examinations revealed that mean stress induced creep effect resulted in intergranular crack initiation and grain boundary cavitation during fatigue tests under R = 0 condition and therefore verified the facts revealed in TEM studies.

Stress-strain dependence and the evolution of dislocation structure in Cu-Mn polycrystalline concentrated solid solutions

Deformation of metallic materials results in dislocations occurrence and accumulation, with establishment of their definite distribution (dislocation substructure). The type of dislocation substructure (DSS) defines largely resistance to deformation and fracture of materials. Quantitatively the interrelation of DSSs and resistance to deformation are studied on a limited number of alloys. Foreign literature lacks studies referring to those issues. The given paper investigates the stress-strain dependences in Cu-Mn polycrystalline solid solutions. Mn concentration in the alloys varied within the range of 10…25 at.%. Polycrystals with 10 and 240 μm mean grain size were investigated. Deformation was applied by means of tension at the velocity of 2.10-2 s-1 and the temperature of 293 K. Using transmission electron microscope at the accelerating voltage of 125 kV, microstructure of the samples was investigated when they were deformed up to various deformation degrees. The types of DSSs were defined. The connection of the deformation stage under tension with the formed types of DSS was discussed. The sequence of transition of DSSs during the process of alloys deformation was defined. Appearance of the new stage of deformation hardening is attributed to the occurrence of the new type of substructure. The occurring “new” DSS develops during the deformation process, while “the old” DSS gradually disappears. Each of the stage of plastic deformation generally has two types of DSSs. The connection of the deformation stage and the strain hardening coefficient with the DSS was defined and it was shown to possess the definite dislocation density.

Development of a comprehensive database of scattering environmental conditions and simulation constraints for offshore wind turbines

Abstract. For the design and optimisation of offshore wind turbines, the knowledge of realistic environmental conditions and utilisation of well-founded simulation constraints is very important, as both influence the structural behaviour and power output in numerical simulations. However, real high-quality data, especially for research purposes, are scarcely available. This is why, in this work, a comprehensive database of 13 environmental conditions at wind turbine locations in the North and Baltic Sea is derived using data of the FINO research platforms. For simulation constraints, like the simulation length and the time of initial simulation transients, well-founded recommendations in the literature are also rare. Nevertheless, it is known that the choice of simulation lengths and times of initial transients fundamentally affects the quality and computing time of simulations. For this reason, studies of convergence for both parameters are conducted to determine adequate values depending on the type of substructure, the wind speed, and the considered loading (fatigue or ultimate). As the main purpose of both the database and the simulation constraints is to compromise realistic data for probabilistic design approaches and to serve as a guidance for further studies in order to enable more realistic and accurate simulations, all results are freely available and easy to apply.

Effect of near-fault and far-fault earthquakes on a historical masonry mosque through 3D dynamic soil-structure interaction

In the scope of this paper, it is aimed to compare the effects of near and far-fault earthquakes on the seismic responses (amplitude, spectrum effect, stress) of a relatively complex historical stone masonry mosque (125-years old Kurtulus Mosque, Gaziantep-Turkey) through soil-structure-interaction (SSI) analysis as well as fixed base solution. The SSI analysis (using direct approach) has also been performed for the effect of boundary types (viscous, elementary) of substructure. A 3D finite element modeling of mosque and substructure soil is built with solid elements, and then the seismic responses of mosque are evaluated by time-history analysis. The near and far-fault motions, which have approximately identical peak ground accelerations from same earthquake, are selected by representing their own characteristics (i.e., velocity, distance, etc.) from the strong ground motion records in previous earthquakes (1979 Imperial Valley, 1992 Erzincan, 1999 Chi-Chi, 1999 Kocaeli, 2010 Darfield). It is found from the results that both the near and far-fault earthquakes mostly lead to the responses similarly significant for both the fixed base and SSI considerations. However, regarding the resonance effect on the mosque, the far-fault motion appears more prominent in fixed base solution. Moreover, the far-fault motions mostly result in high amplitudes in the viscous boundary of SSI compared to the elementary boundary. When compared to the fixed base and SSI due to the near and far-fault effects, it is seen that the SSI increases amplitude and stresses. Overall from the comparisons, the study indicates that the far-fault motion could be employed together with the near-fault motions for assessment of such historical mosques for further considerations.

Synthesis of 3,5-Disubstituted Isoxazoles Containing Privileged Substructures with a Diverse Display of Polar Surface Area.

We designed and synthesized the molecular framework of 3,5-disubstituted isoxazoles containing privileged substructures with various substituents which uniquely display polar surface area in a diverse manner. A library of 3,5-disubstituted isoxazoles were systematically prepared via 1,3-dipolar cycloaddition of alkynes with nitrile oxides prepared by two complementary synthetic routes; method A utilized a halogenating agent with a base and method B utilized a hypervalent iodine reagent. Through the biological evaluation of corresponding isoxazoles via three independent phenotypic assays, the different pattern of biological activities was shown according to the type of privileged substructure and substituent. These results demonstrated the significance of molecular design via introducing privileged substructures and various substituents to make a diverse arrangement of polar surface area within a similar 3-dimensional molecular framework.

Dynamic properties and seismic vulnerability of typical RC bridges located in México

Most of the bridges built before the 80´s were designed with out of date seismic regulation codes. Important changes in last decades make essential to re-evaluate the vulnerability of the bridges. In Mexico, most of the medium-length RC bridges were designed for lateral loads recommended in seismic codes of the 70’s. Those bridges located on high-risk zones are particularly vulnerable to earthquake ground motions. This study presents the results of evaluating the dynamic properties of a family of existing typical RC bridges in Mexico by conducting ambient vibration measurements. The selection of the structures is based on statistical analyses of the general characteristics of RC bridges in the country and all of them are located in medium- and high-intensity seismic zones. After evaluating dynamic properties, a detailed seismic vulnerability assessment of the structure is proposed. Results allow to determine the more vulnerable structures to be candidates for rehabilitation and retrofit actions. Particular attention is devoted to evaluate the relationship between seismic vulnerability and substructure type of the bridges.

Value of graph topology in vascular biometrics

Biometrics such as retina, palm vein, wrist vein and hand vein are becoming increasingly popular because of ease of use, in-built liveness detection and a contact free capture process. Here the authors show the benefits of graph representation for all such vascular biometrics and the advantages of graph topology in matching vascular biometric graphs. The authors find that different types of small substructures dominate in the four classes of vascular graphs due to the way the vasculature is built in the human body. The authors show that simple graph structures can be used to bring down the registration time by over 50% compared with registration using edges alone, and that cost functions that include matching the local graph neighbourhood around compared node pairs improve matching performance. Distance measures based on the number of vertices or edges in the maximum common subgraph are shown to discriminate significantly better than using a simple count of matched vertices, as in the iterative closest point based point pattern matching. For graphs whose topology is close to that of proximity graphs, edge-based distance measures were found to perform best. These results are demonstrated for all four vascular modalities.

Change of deformation characteristics and dislocation substructure of nonferrous metals under influence of magnetic field

The objects of the study were polycrystalline copper of M00b grade and commercially pure titanium BT1-0. Microindentation was carried out on the samples of titanium BT1-0 in the initial state, immediately after magnetic field exposure of 0.4 T and after certain time intervals. The defect substructure of cooper samples M00b, subjected to loading to failure in the creep mode under the influence of magnetic field of 0.35 T and without it, was investigated by the methods of electron diffraction microscopy. It was revealed that the effect of magnetic field exposure on commercially pure titanium BT1-0 leads to the decrease in microhardness with the subsequent stabilization during the time that depends on the processing parameters. And the effect of the magnetic field exposure on copper during the process of creeping results in the redistribution of dislocation substructure types. Also, there are changes in quantitative characteristics of dislocation substructures.

Enhancing Shear Strength of Capbeam–Column Joints in Existing Multicolumn Bent Bridges Using an Innovative Method

AbstractNonintegrated multicolumn bents are the common type of substructure in existing bridges. Among all possible seismic defects in their behavior, capbeam–column joint behavior has not properly been acknowledged so far. Although for other defects some retrofit methods are available, there are only a few methods proposed for improving the shear strength of these joints. The purpose of this research was to assess the cyclic response of such bents and suggest a practical retrofit method for improving joint behavior without significant damage. To this end, a ¼-scale two-column bent, representative of existing bridges built before 1990, was tested. Using test results, a passive retrofitting method based on the increasing shear strength of joints was developed. The performance of the proposed method was examined on a new specimen similar to the first one. The results show that, unlike the reference bent, which was damaged extensively in joint regions, the joints in the retrofitted specimen did not suffer an...

Research on the rigid-flexible multibody dynamics of concrete placing boom

Abstract A method is proposed for rigid-flexible multibody dynamic modeling of concrete placing booms, to improve the calculation efficiency and ensure the accuracy. Concrete placing booms consist of four types of substructures, according to the slender rods and the mechanism features. The transfer matrixes of substructures are derived based on the discrete time transfer matrix method. Then, the manipulator's overall transfer matrix is assembled and used for the numerical calculation. An experiment based on a test rig is performed to validate the proposed method, and a model based on ADAMS (short of MSC.ADAMS) is also established to compare the calculating efficiency of the proposed method.

Fossil group origins

Fossil groups are expected to be the final product of galaxy merging within galaxy groups. In simulations, they are predicted to assemble their mass at high redshift. This early formation allows for the innermost $M^\ast$ galaxies to merge into a massive central galaxy. Then, they are expected to maintain their fossil status because of the few interactions with the large-scale structure. In this context, the magnitude gap between the two brightest galaxies of the system is considered a good indicator of its dynamical status. As a consequence, the systems with the largest gaps should be dynamically relaxed. In order to examine the dynamical status of these systems, we systematically analyze, for the first time, the presence of galaxy substructures in a sample of 12 spectroscopically-confirmed fossil systems with redshift $z \le 0.25$. We apply a number of tests in order to investigate the substructure in fossil systems in the two-dimensional space of projected positions out to $R_{200}$. Moreover, for a subsample of 5 systems with at least 30 spectroscopically-confirmed members we also analyze the substructure in the velocity and in the three-dimensional velocity-position spaces. Additionally, we look for signs of recent mergers in the regions around the central galaxies. We find that an important fraction of fossil systems show substructure. The fraction depends critically on the adopted test, since each test is more sensible to a particular type of substructure. Our interpretation of the results is that fossil systems are not, in general, as relaxed as expected from simulations. Our sample of 12 spectroscopically-confirmed fossil systems need to be extended in order to compute an accurate fraction, but our conclusion is that it is similar to the fraction of substructure detected in non-fossil clusters. THIS ABSTRACT IS TRUNCATED.