Deformation Parameters Research Articles

Accretion flow in deformed Kerr spacetime: spectral energy distributions from free-free emission

In this paper, we study the properties of accretion flow including its spectral features in Johannsen and Psaltis (JP) non-Kerr spacetime. In doing so, we numerically solve the governing equations that describe the flow motion around the compact objects in a general relativistic framework, where spin (ak ) and deformation parameters (ε) demonstrate the nature of the central source, namely black hole (BH) or naked singularity (NS). With this, we obtain all possible classes of global accretion solutions (i.e., O, A, W and I-type) by varying the energy (E) and angular momentum (λ) of the relativistic accretion flow, and examine the role of thermal bremsstrahlung emission in studying the spectral energy distributions (SEDs) of the accretion disc. We divide the parameter space in λ-E plane in terms of the different classes of accretion solutions for BH and NS models. We further calculate the disc luminosity (L) corresponding to these accretion solutions, and observe that I-type solutions yield higher L and SEDs than the remaining types of solutions for both BH and NS models. For BH model, SEDs for W and I-type solutions differ significantly from the results for O and A-type solutions for low E values. On the contrary, for NS model, SEDs for different accretion solutions are identical in the whole parameter space of λ and E. We also examine the effect of ε on the SEDs and observe that a non-Kerr BH yields higher SEDs than the usual Kerr BH. Finally, for accretion solutions of identical E and λ, we compare the SEDs obtained from BH and NS models, and find that naked singularity objects produce more luminous power spectra than the black holes.

Myocardial strain of the left ventricle by speckle tracking echocardiography: From physics to clinical practice.

Speckle tracking echocardiography (STE) is a reliable imaging technique of recognized clinical value in several settings. This method uses the motion of ultrasound backscatter speckles within echocardiographic images to derive myocardial velocities and deformation parameters, providing crucial insights on several cardiac pathological and physiological processes. Its feasibility, reproducibility, and accuracy have been widely demonstrated, being myocardial strain of the various chambers inserted in diagnostic algorithms and guidelines for various pathologies. The most important parameters are Global longitudinal strain (GLS), Left atrium (LA) reservoir strain, and Global Work Index (GWI): based on large studies the average of the lower limit of normality are -16%, 23%, and 1442 mmHg%, respectively. For GWI, it should be pointed out that myocardial work relies primarily on non-invasive measurements of blood pressure and segmental strain, both of which exhibit high variability, and thus, this variability constitutes a significant limitation of this parameter. In this review, we describe the principal aspects of the theory behind the use of myocardial strain, from cardiac mechanics to image acquisition techniques, outlining its limitation, and its principal clinical applications: in particular, GLS have a role in determine subclinical myocardial dysfunction (in cardiomyopathies, cardiotoxicity, target organ damage in ambulatory patients with arterial hypertension) and LA strain in determine the risk of AF, specifically in ambulatory patients with arterial hypertension.

Study of influence of the auxiliary factors onto characteristics of elastic-plastic deformation in the stress concentrator of the beam-wall with broken edges

The thin-walled steel beam-wall with broken edges is being investigated, which is a part of many structures. The wall of this beam consists of two prismatic parts with a linear transition from a smaller to a larger wall height, together forming an angular upper edge with the edges of the prismatic parts. The lower linear edge of the wall is attached to the sheathing.The beam-wall is subjected to static and cyclic loads, under which elastic-plastic deformations strains may occur at in the stress concentrator. This leads to failure of static strength and growth of fatigue cracks. The factors influencing the parameters of elastic-plastic deformation at in the stress concentrator of this beam are practically unstudied. The article under discussion presents the results of studying the influence of the beam-wall thickness and load vector balancing on the values of static and cyclic ranges of elastic-plastic deformations strains at in the stress concentrator. It has had been found that load vector balancing significantly improves the results of elastic-plastic deformations strains under single static loading and allows for the use of a larger load increment to achieve the same results as when no balancing is applied. Applying load vector balancing stabilizes the cyclic deformation loop practically from the first cycle. If balancing is absent, stabilization occurs only from the third cycle. Unlike static ones, the values of cyclic ranges do not depend on the application or non-application of balancing and remain practically stable with fixed geometric parameters and loading. Gradual reduction in the thickness of the beam-wall causes an increase in the range (static and cyclic) of elastic-plastic deformations strains at in the stress concentrator. The obtained results will shorten the time required for planning serial calculations of elastic-plastic deformation of a the beam-wall with edge break broken edges to develop appropriate design techniques.

Optimization of Adaptive Active Support Parameters for Large Deformation Prestressed Anchor Ropes in Soft Rock Tunnels Using Genetic Algorithm Based Computer Applications

The large deformation of soft rock tunnel is an important problem to be solved urgently with the development of engineering technology. In order to improve the application effect of prestressed anchor cable adaptive active support system, this paper puts forward an optimization method based on adaptive genetic algorithm, reviews the research status of prestressed anchor support in soft rock tunnel, and analyzes and evaluates the existing methods. This paper introduces the construction process of AGA model, establishes the problem description model and genetic optimization algorithm selection model, and constructs the adaptive active support model of prestressed anchor cable. The model adopts an optimization algorithm with a total of 100 iterations. The Simple Genetic Algorithm and Parallel Genetic Algorithm are selected to evaluate the anchoring force, the control effect of surrounding rock displacement, the erosion of supporting structure and the construction time by comparative test. The test results show that AGA has a good effect on the anchoring force, the minimum anchoring force is 457 kN, and the displacement of surrounding rock is controlled within 1.21-1.59mm, which has a good influence on the quality of supporting structure and the construction completion time. Finally, the application of AGA model in parameter optimization of prestressed anchor cable in soft rock tunnel is summarized, and the future research direction is put forward.

РАСЧЕТ И ПОСЛЕДОВАТЕЛЬНОСТЬ ПРОЕКТИРОВАНИЯ СИЛОПРИВОДОВ ИЗ МАТЕРИАЛА С ПАМЯТЬЮ ФОРМЫ ДЛЯ ДЕФОРМИРУЮЩИХ И ИСПЫТАТЕЛЬНЫХ УСТРОЙСТВ

Development of deforming and testing devices with power drive from the material with shape memory demands implementing a specified consequence of steps at its designing and calculating.A necessary consequence of designing and calculating a separate power element, as well as a whole power drive on the base of the obtained experience in developing such equipment is represented in this work.All designing and calculating stages of the power drive from a shape choice and size of a power element to the needed parameters (deformation, power and thermal parameters) are considered.A special attention is paid to the parameters' interconnection for providing a necessary operation efficiency of the power drives.

Никельсодержащие нанокомпозиты на основе изотактического полипропилена и полиэтилена высокого давления

The effect of nanofiller (NF) additives containing nickel oxide nanoparticles stabilized by a polymer matrix of high pressure polyethylene (PE) obtained by the mechanochemical method on the structure and properties of metal-containing nanocomposites based on isotactic polypropylene (PP) and high pressure polyethylene(PE) using differential thermal (DTA) and X-ray phase (XRF) and SEM analyzes. The improvement of strength, deformation and rheological parameters, as well as thermal-oxidative stability of the obtained nanocomposites was revealed, which, apparently, is associated with the synergistic effect of interfacial interaction of nickel-containing nanoparticles in the PE matrix with the components of the PP/PE polymer composition. It is shown that nanocomposites based on PP/PE/NF can be processed both by pressing method and by injection molding and extrusion methods, which expands the scope of its application.

Refined model of leather

The structure of finished leather and semi-finished products differ in physical and mechanical parameters. To obtain the properties of elasticity, pliability, and viscosity required in leather production, it is necessary to ensure their values that guarantee the high quality of the resulting product. In this article, a model for finished leather is obtained based on combining the viscoelastic Kelvin model with the deformationinert Khusanov model and the Bingham–Shvedov viscoplastic model. This model makes it possible to improve the elastic-viscous plastic deformation of a fibrous material (leather). The possibility of clarifying the pattern of change in the deformation curve depending on the time the fibrous material is loaded by a certain force was explored. The aim of refining the deformation curve is that in known models, at the initial moment of loading, deformation occurs instantly up to a certain value, which does not fully describe the real physical process of deformation of the material. Consequently, in the proposed refined model, the deformation is fixedat zero value, which provides a real physical pattern of deformation of the fibrous material. The refined model will serve designers of technological machines to develop parameters of deformation during the mechanical processing of elastic-viscous plastic materials.

Multispectral Image Stitching via Global-Aware Quadrature Pyramid Regression.

Image stitching is a critical task in panorama perception that involves combining images captured from different viewing positions to reconstruct a wider field-of-view (FOV) image. Existing visible image stitching methods suffer from performance drops under severe conditions since environmental factors can easily impair visible images. In contrast, infrared images possess greater penetrating ability and are less affected by environmental factors. Therefore, we propose an infrared and visible image-based multispectral image stitching method to achieve all-weather, broad FOV scene perception. Specifically, based on two pairs of infrared and visible images, we employ the salient structural information from the infrared images and the textual details from the visible images to infer the correspondences within different modality-specific features. For this purpose, a multiscale progressive mechanism coupled with quadrature correlation is exploited to improve regression in different modalities. Exploiting the complementary properties, accurate and credible homography can be obtained by integrating the deformation parameters of the two modalities to compensate for the missing modality-specific information. A global-aware guided reconstruction module is established to generate an informative and broad scene, wherein the attentive features of different viewpoints are introduced to fuse the source images with a more seamless and comprehensive appearance. We construct a high-quality infrared and visible stitching dataset for evaluation, including real-world and synthetic sets. The qualitative and quantitative results demonstrate that the proposed method outperforms the intuitive cascaded fusion-stitching procedure, achieving more robust and credible panorama generation. Code and dataset are available at https://github.com/Jzy2017/MSGA.

Prognostic value of myocardial deformation parameters for outcome prediction in tetralogy of Fallot

BackgroundThe prognostic value of myocardial deformation parameters in adults with repaired tetralogy of Fallot (rTOF) has not been well-elucidated. We therefore aimed to explore myocardial deformation parameters for outcome prediction in adults with rTOF using cardiovascular magnetic resonance imaging (CMR). MethodsAdults with rTOF and at least moderate pulmonary regurgitation were identified from an institutional prospective CMR registry. Left ventricular (LV) and right ventricular (RV) global strains were recorded in longitudinal (GLS), circumferential (GCS), and radial (GRS) directions. Major adverse cardiovascular events (MACE) were defined as a composite of mortality, resuscitated sudden death, sustained ventricular tachycardia (>30 seconds), or heart failure (hospital admission >24 hours). In patients with pulmonary valve replacement (PVR), pre- and post-PVR CMR studies were analyzed to assess for predictors of complete RV reverse remodeling, defined as indexed RV end-diastolic volume (RVEDVi) <110 mL/m2. Logistic regression models were used to estimate the odds ratio (OR) per unit change in absolute strain value associated with clinical outcomes and receiver operator characteristic curves were constructed with area under the curve (AUC) for select CMR variables. ResultsWe included 307 patients (age 35 ± 13 years, 59% (180/307) male). During 6.1 years (3.3–8.8) of follow-up, PVR was performed in 142 (46%) and MACE occurred in 31 (10%). On univariate analysis, baseline biventricular ejection fraction (EF), mass, and all strain parameters were associated with MACE. After adjustment for LVEF, only LV-GLS remained independently predictive of MACE (OR 0.822 [0.693–0.976] p = 0.025). Receiver operator curves identified an absolute LV-GLS value less than 15 and LVEF less than 51% as thresholds for MACE prediction (AUC 0.759 [0.655–0.840] and 0.720 [0.608–0.810]). After adjusting for baseline RVEDVi, RV-GCS (OR 1.323 [1.094–1.600] p = 0.004), LV-GCS (OR 1.276 [1.029–1.582] p = 0.027) and LV-GRS (OR 1.101 [1.0210–1.200], p = 0.028) were independent predictors of complete remodeling post-PVR remodeling. ConclusionBiventricular strain parameters predict clinical outcomes and post-PVR remodeling in rTOF. Further study will be necessary to establish the role of myocardial deformation parameters in clinical practice.

Methodology for the induction of myocardial infarction and cardiac function evaluation.

Cardiovascular disease (CVD) is the main cause of death worldwide, with myocardial infarction (MI) being the most prevalent pathology involved in CVD. MI is characterized by a deficiency in oxygen supply to the myocardium, thereby promoting ventricular remodeling of the ischemic and remote zone of the heart. Cardiac remodeling associated with MI could promote the development of heart failure and finally death. For these reasons, it is important to develop animal models that mimic human cardiac disease which could help to identify new mechanisms involved in the pathology and, consequently, develop new therapeutic strategies. We herein describe in detail a protocol for MI induction with low mortality rate (<15%) in rats by ligation of the left anterior descending artery. In addition, we also describe two imaging techniques which allow to evaluate cardiac structure and function-including deformation parameters in rats such as transthoracic echocardiography and cardiac magnetic resonance. This animal model could be useful for acute and chronic studies and for evaluating the potential usefulness of different treatments.

Blandford-Znajek jets in MOdified Gravity

General relativity (GR) will be imminently challenged by upcoming experiments in the strong gravity regime, including those testing the energy extraction mechanisms for black holes. Motivated by this, we explore magnetospheric models and black hole jet emissions in Modified Gravity (MOG) scenarios. Specifically, we construct new power emitting magnetospheres in a Kerr-MOG background which are found to depend non-trivially on the MOG deformation parameter. This may allow for high-precision tests of GR. In addition, a complete set of analytic solutions for vacuum magnetic field configurations around static MOG black holes are explicitly derived, and found to comprise exclusively Heun's polynomials.

Establishing the hot working window for the forging of S32906 super duplex stainless steel through considering deformation parameter sensitivities

The evaluation of the hot workability of the super duplex stainless steel (SDSS) material still lacks scientific and theoretical basis, leading to the frequent occurrence of unacceptable defects in its forgings. In this study, a novel method for estimating the hot workability of S32906 SDSS was proposed and verified through forging. Firstly, the flow behavior and microstructural characteristics were demonstrated by conducting isothermal compression tests at the deformation temperature from 1000 °C to 1250 °C and the strain rate from 0.01 s−1 to 10 s−1. The influence of microstructure on flow and work hardening behaviors was correlated and displayed. Then, based on the deformation characteristics presented through the variations of strain rate sensitivity (SRS) and deformation temperature sensitivity (DTS) coefficients, the SRS and DTS maps were constructed and overlaid for obtaining the hot working window. Ultimately, a large plate type forging of S32906 SDSS applied in engineering was used to verify the applicability of the obtained window. The new method can provide an in-depth understanding of hot workability and enable control of the forming and microstructural properties for this unique material.

Exploring the Implications of the Deformation Parameter and Minimal Length in the Generalized Uncertainty Principle

Exploring the Implications of the Deformation Parameter and Minimal Length in the Generalized Uncertainty Principle

Solutions by Quadratures of Complex Bernoulli Differential Equations and Their Quantum Deformation

It is shown that the complex Bernoulli differential equations admitting the supplementary structure of a Lie–Hamilton system related to the book algebra b2 can always be solved by quadratures, providing an explicit solution of the equations. In addition, considering the quantum deformation of Bernoulli equations, their canonical form is obtained and an exact solution by quadratures is deduced as well. It is further shown that the approximations of kth-order in the deformation parameter from the quantum deformation are also integrable by quadratures, although an explicit solution cannot be obtained in general. Finally, the multidimensional quantum deformation of the book Lie–Hamilton systems is studied, showing that, in contrast to the multidimensional analogue of the undeformed system, the resulting system is coupled in a nontrivial form.

Oilfield Reservoir Parameter Inversion Based on 2D Ground Deformation Measurements Acquired by a Time-Series MSBAS-InSAR Method

Time-series ground deformation monitoring and reservoir parameter inversion are crucial for the dynamic assessment of oilfield resources and sustainable exploitation in oilfields. As some of the regions with the richest oil reserves in China, the oilfield areas in the western Qaidam Basin were selected as a typical study area. Firstly, we used SAR images collected by the Sentinel-1A satellite from January 2021 to December 2022 and applied the multidimensional small baseline subset (MSBAS) method to obtain vertical and east–west deformation measurements. On this basis, a nonlinear Bayesian inversion method was applied to model the shallow reservoir in a series of complex deformation areas, based on a single-source model and a multi-source model, respectively. As a result, the ground deformation monitoring results obtained by long time-series InSAR clearly reflect the uneven ground deformation caused by the oil extraction and water injection operation processes. There was slight subsidence in the Huatugou oilfield, while significant uplift deformation occurred in the Ganchaigou oilfield and the Youshashan oilfield, with a maximum uplift rate of 48 mm/year. Further analysis indicated that the introduction of the 2D deformation field helps to improve the robustness of oilfield reservoir parameter inversion. Moreover, the dual-source model is more suitable than the single-source model for inverting reservoir parameters of complex deformation. This study not only fills the gap of InSAR deformation monitoring for the oilfields in the western Qaidam Basin but also provides a theoretical reference for the model and method selection of reservoir parameter inversion in other oilfields.

A comparison between theoretical results and experimental data of transition probability B(E2), deformation parameter, and intrinsic quadrupole moments for different nuclei with mass number A = 44

A comparison has been made between theoretical results and the experimental data for different nuclei (even-even) that possess the same mass number A = 44 and which have close values of the experimental deformation parameter such as 16S44, 18Ar44, 20Ca44 and 22Ti44. The core-polarization effects and model space were adopted through the inclusion of effective charges. Transition probability B(E2), theoretical deformation parameters, and theoretical intrinsic quadruple moments were calculated using two different interactions for each case, the first case the hasp interaction for nuclei in the sd shell, and the fpd6 interaction for nuclei in the fp shell, the second case the vpnp interaction for nuclei in the sd shell, and the kb3 interaction for nuclei in the fp shell, as well as adopted to different effective charges, such as Bohr and Mottelson effective charges, standard effective charges, and the effective charges from program NuShellX. The theoretical results of the transition probability B(E2), deformations parameters, and intrinsic quadruple moments were compared and found to be close to the experimental values for these nuclei.

Possibility of obtaining rolled sheet from white iron with increased plasticity

Рroblem In the work, a study of the technology of manufacturing sheet metal up to 2 mm thick from white ledeburite cast iron alloyed with vanadium was carried out. Сast-iron purveyances forged preliminary. After forging purveyances were rolled with the different wringing out. At rolling a total degree of deformation was 70%. The additional annealing helped to bring down hardness of sheet and moulding of pipes became possible. White cast-iron has high plasticity because there are phase transformations in a vanadium eutecticum cementite. Goal. The goal of work is a study of sheet rolling of white cast-iron’s bars to use for the armour and weld-fabricated pipes. Methodology. Experimental cast iron contains 2.7 - 2.85% C and up to 2% V. 30 kg of castings were melted. The total degree of deformation was 70%. After forging, rolling was carried out on a two-roll laboratory mill on rolls with a smooth barrel. Results. The technological scheme for the production of white cast iron forgings is applied, which includes preliminary annealing, forging with a degree of deformation from 10 to 15%, intermediate annealing and final forging with a total ε=70%. Оriginality The use of carbide transformation in vanadium-doped cementite made it possible to carry out combined pressure treatment and obtain sheets up to 2 mm thick from iron castings Preliminary hot forging greatly stimulates and accelerates the process of cementite disintegration into austenite and vanadium carbides during high-temperature exposure. Rolling of forging blanks was carried out and the influence of thermal and deformation parameters on the structure of cast iron was investigated. Рractical value. Application of final heat treatment after deformation of cast iron provides a level of mechanical properties that corresponds to the properties of high-strength armor steels, and the hardness indicators even exceed them. Thinner sheets of such cast iron can be used to create compositions of multilayer armor with increased ballistic resistance from several materials with different properties.

Development of the method for determining the deformation parameters and remidal stresses of metal in the manufacture of straight-seached pipes of large diameter using expansion

Since 2020, in Ukraine, LLC NVP «UKRTRUBOIZOL» began to operate a technological line for the production of large-diameter pipes (TVD) for main oil and gas pipelines with a hydromechanical expander. From 2023, interstate GOST 20295-85 and GOST 10706-76 ceased to be valid in Ukraine. Formulation of the problem. Ukrainian standards are needed. It is necessary to determine the rational values of the deformations and the effectiveness of the expansion to reduce the residual stresses in the metal of the pipes. Goal. Development of Ukrainian standards for TVD production and determination of the effect of expansion on residual stresses. Method. The method of cutting rings was used. The results. Developed and implemented with the participation of author: DSTU 9219:2023; DSTU 9218:2023 and TU 24.2–05757883–095:2022. Pipes with a diameter of 630 mm, with a wall of 8 mm, made of S335 steel and hot-rolled rolled sheet were studied. The opening between the longitudinal edges of the pipe blank after bending was 70-80 mm. For the ring after welding, the opening was 180 mm and for the rings expanded by 0.8%, 1.2% and 0.4% -58-53 mm. This indicates that the residual expansion stresses were much smaller than in the pipe after welding the seam, and the amount of expansion change from 0.4% to 1.2% does not affect the residual stresses. Scientific novelty. For the first time, for the JCOE technology of production of TVD from rolled hot-rolled sheet, the influence of expansion on residual stresses was determined experimentally. It was shown that the opening of the rings during expansion is significantly reduced. For the first time, the influence of the amount of expansion on the reduction of residual stresses was determined for the JCOE technology of TVD production. It is shown that deformations of 0.4-1.2% give the same opening of the rings after expansion. Practical significance. The obtained results can be useful for the personnel of steel welded TVD production enterprises and project organizations sn the design of oil and gas pipelines

Mechanical properties and rate-sensitive deformation of AA6063 aluminum alloys at 298 K, 78 K, and 4 K

The mechanical properties and rate-sensitive deformation of T4 and T6 AA6063 aluminum alloys have been analyzed at 298 K, 78 K, and 4 K. The strength, ductility, and work hardening capacity of two alloys increase with decreasing deformation temperature. Plastic deformation of AA6063-T4 is accompanied by adiabatic flow stress instabilities at 4 K and the Portevin-Le Chatelier (PLC) effect at 298 K. The alloy shows a better synergy of flow stress and work hardening than the T6 condition, determined by the underlying microstructure. The limited ability of dislocation storage in T6 alloy arises from shearing β″ particles and the enhanced dislocation annihilation occurring in pure Al matrix. The failure of the alloys is promoted by void nucleation at intermetallic particles before the Considére criterion is fulfilled. AA6063-T6 exhibits positive strain rate sensitivity (SRS) at three temperatures. Dislocations-β″ particle interactions determine its SRS and are a rate-controlling process at 298 K. AA6063-T4 shows negative strain rate sensitivity (nSRS) at 298 K controlled by dislocation-solute interactions. Data for SRS and thermodynamic deformation parameters characterizing different mechanisms in T4 and T6 alloys between 4 K and 298 K are discussed. The results indicate that plastic deformation produces vacancies by jogs' dragging at 298 K, but this process does not occur at 78 K and 4 K.

Study of Kinematic and Deformation Parameters of Rolling of Compressor Blade Workpieces

Study of Kinematic and Deformation Parameters of Rolling of Compressor Blade Workpieces