Analytical Calculations Research Articles

Performance Analysis of Shear Wall Joint Connection in Highrise Building Using Finite Element

Multi-story buildings have a risk of structural failure, especially at joint connections, including raft elements and shear walls, due to the interaction behavior of the shear joints. The problem raised in this research is how to analyze the performance of raft foundation shear wall structural connections in high-rise buildings. The researchers started by simulating the initial model using the element method to find out the detailed capabilities of the raft foundation and shear walls and obtain values that could measure the capabilities of the substructure used. The results of this research explain the results of the evaluation of connection performance, namely, the pile raft phase with fc' 35 MPa and the shear wall phase with fc' 50 MPa. From the analysis in this research, visualization from the ABAQUS program of the force conditions acting on the connection structure was obtained, namely compression damage of 0.0021 at an ultimate compressive stress of 43 MPa and 0.0006 at an ultimate compressive stress of 57.97 MPa. We also perform analytical calculations to determine the tensile and compressive strain values. In the future, it is hoped that it will be possible to make part of the reference the use of connections with similar models and sizes at project work stages with the same characteristics as a contribution to developing building structural safety requirements.

Symmetry, gauge freedoms, and the interpretability of sequence-function relationships.

Quantitative models that describe how biological sequences encode functional activities are ubiquitous in modern biology. One important aspect of these models is that they commonly exhibit gauge freedoms, i.e., directions in parameter space that do not affect model predictions. In physics, gauge freedoms arise when physical theories are formulated in ways that respect fundamental symmetries. However, the connections that gauge freedoms in models of sequence-function relationships have to the symmetries of sequence space have yet to be systematically studied. Here we study the gauge freedoms of models that respect a specific symmetry of sequence space: the group of position-specific character permutations. We find that gauge freedoms arise when model parameters transform under redundant irreducible matrix representations of this group. Based on this finding, we describe an "embedding distillation" procedure that enables analytic calculation of the number of independent gauge freedoms, as well as efficient computation of a sparse basis for the space of gauge freedoms. We also study how parameter transformation behavior affects parameter interpretability. We find that in many (and possibly all) nontrivial models, the ability to interpret individual model parameters as quantifying intrinsic allelic effects requires that gauge freedoms be present. This finding establishes an incompatibility between two distinct notions of parameter interpretability. Our work thus advances the understanding of symmetries, gauge freedoms, and parameter interpretability in sequence-function relationships.

Three-point energy correlators in hadronic Higgs boson decays

We present the analytic calculation of the leading-order three-point energy correlator (EEEC) in hadronic Higgs decays, including both the gluon-initiated channel H→gg+X and quark-initiated channel H→qq¯+X. The phase-space integration is evaluated directly using Mandelstam variables sij=(pi+pj)2, and the appearing square roots can be rationalized by either conformal ratios or celestial coordinate variables. Throughout the calculation, we observe the same transcendental function space as in N=4 super–Yang-Mills theory and e+e−→hadrons. Different infrared limits are also explored using the full analytic result, offering the fixed-order data for EEEC factorization and resummation. Given its nontrivial shape dependence, the EEEC presents an excellent opportunity to explore the dynamics of gluon jets originating from the H→gg decay channel at future lepton colliders. Published by the American Physical Society 2024

Substantiation of the Use of a Flexible Chain-Type Subsoiler for Improving the Agrotechnological Properties of Soil

Technogenic influence on agricultural soils leads to the transformation of their morphological features, significantly worsens their agrochemical, physical, mechanical and agrotechnological properties, prevents the optimal use of potential soil fertility and, as a result, leads to a decrease in crop yield. Mechanical soil decompaction when using various types of subsoilers, including the flexible chain-type working body (the chain), is used to prevent the negative consequences of technogenic influence. According to the results of the analytical calculations, the proportionality factor of the chain length, which determines the ratio of the width of the plow grip to the chain length of a flexible subsoiler, was established. The specified coefficient is proportional and equals 2.4. The use of the specified coefficient allows us, at the stage of the development of the design and technological documentation, to determine the main design parameter of the flexible subsoiler, which is the length of the used chain depending on the width of the plow grip. The surface of the field cultivated with the experimental tillage tool meets the requirements for sowing the agricultural crops without performing additional technological operations.

Modulating Ca2+ influx into adrenal chromaffin cells with short-duration nanosecond electric pulses

Isolated bovine adrenal chromaffin cells exposed to single 2-, 4-, or 5-ns pulses undergo a rapid, transient rise in intracellular Ca2+ mediated by Ca2+ entry via voltage-gated Ca2+ channels (VGCCs), mimicking the activation of these cells in vivo by acetylcholine. However, pulse durations 150 ns or longer elicit larger amplitude and longer-lived Ca2+ responses due to Ca2+ influx via both VGCCs and a yet to be identified plasma membrane pathway(s). To further our understanding of the differential effects of ultrashort versus longer pulse durations on Ca2+ influx, chromaffin cells were loaded with calcium green-1 and exposed to single 3-, 5-, 11-, 25-, or 50-ns pulses applied at their respective Ca2+ activation threshold electric fields. Increasing pulse duration from 3 or 5 ns to only 11 ns was sufficient to elicit increased amplitude and longer-lived Ca2+ responses in the majority of cells, a trend that continued as pulse duration increased to 50 ns. The amplification of Ca2+ responses was not the result of Ca2+ release from intracellular stores and was accompanied by a decreased effectiveness of VGCC inhibitors to block the responses and a reduced reliance on extracellular Na+ and membrane depolarization to evoke the responses. Inhibitors of pannexin channels, P2X receptors, or non-selective cation channels failed to attenuate 50-ns-elicited Ca2+ responses, ruling out these Ca2+-permeable channels as secondary Ca2+ entry pathways. Analytical calculations and numerical modeling suggest that the parameter that best determines the response of chromaffin cells to increasing pulse durations is the time the membrane charges to its peak voltage. These results highlight the pronounced sensitivity of a neuroendocrine cell to pulse durations differing by only tens of nanoseconds, which has important implications for the future development of nanosecond pulse technologies enabling electrostimulation applications for spatially focused and graded in vivo neuromodulation.

Analytical Calculation of Relationship Temperature and Fatigue and Creep Strength Based on Thermal Activation.

The purpose of this study was to formulate a mathematical expression for the temperature dependence of adhesive strength using various parameters. Adhesive structures are typically exposed to a broad temperature range, spanning from low to high temperatures; therefore, understanding how their strength depends on temperature is crucial. The strength was measured through tensile, fatigue, and creep tests at temperatures ranging from -60 °C to 135 °C. The properties of these test types were thoroughly investigated by analyzing the strength of the test results from a thermal activity perspective. The results demonstrate that there is a clear relationship between temperature and strength. The intensity decreased with temperature according to the exponential function and could be accurately represented using the parameters of thermal activity. The temperature at which the strength begins to decrease in the fatigue test was higher than in the static tests. Consequently, we were able to accurately express the relationship between the temperature and intensity using certain parameters. Few studies successfully developed a precise nonlinear relationship between temperature and intensity using approximate expressions.

COMPARATIVE ANALYSIS OF CALCULATION METHODS OF CLT STRUCTURES

One of the important tasks of modern construction is the search for new constructive solutions and the introduction of new construction technologies. Cross-Laminated Timber (CLT) technology is a new material for Ukraine that has proven itself in Europe and America as effective and environmentally friendly with many advantages. Since CLT panels are not widely distributed, studied and do not contain references in the normative literature in Ukraine, the study of these structures is extremely relevant. This paper presents a comparative analysis of the CLT calculation methods of panels: using the RFEM 6 and LIRA-FEM software and analytical calculation. The research concerns three types of panels: three-layer, five-layer, and seven-layer under the action of a load of 1.5 and 5.0 kN/m2. The main parameter under consideration is the vertical deflection of the panels. The results of all calculations are collected in one table, where you can analyze the discrepancy between different methods of calculating the CLT structures.

CFD MODELING OF THE GM-50 (E-50-3.9-440GM) BOILER FURNACE

The main purpose of the work is to analyze the feasibility of replacing standard burners with burners that operate using jet niche technology burners in power boilers, such as the GM-50 steam boiler (E-50-3.9-440GM). To achieve this goal, a computer model of the steam boiler and burners was built. The study was conducted using the ANSYS Student software suite. The application of numerical modeling methods using the ANSYS Student software suite allowed for a detailed analysis of the fuel combustion process in the steam boiler, evaluate its efficiency, and examine its impact on environmental indicators. The object of the study is the processes occurring during the combustion of gaseous fuel and their impact on the performance indicators of the GM-50 power boiler. The subject of the study is the CFD model of the fuel boiler GM-50, whose standard burners are capable of operating on both liquid and gaseous fuel. Methane was used as the fuel, and both standard axial burners and jet niche technology burners were used, which are more environmentally friendly. Verification of the CFD model, which was performed using a known analytical method, indicates that the discrepancy between the analytical calculations and the model calculations does not exceed 6.7 %. The average temperature of the flue gases in the “festoon window” was chosen as the comparison parameter. Analytically, the temperature value was obtained to be 1117 °C. The calculation using the CFD model, developed in ANSYS-CFX, indicates that the temperature value should be 1042 °C. It was determined that standard burners are less environmentally friendly than, for example, modern jet niche technology burners. For an air excess coefficient α = 1.2, the average value of nitrogen oxides at the outlet from the burner is 187 ppm. There is sense in replacing standard burners, for example, with jet niche technology burners, which are the most suitable for replacing standard ones. Bibl. 24, Fig. 6.

Sequential Selective Dissolution of Coinage Metals in Recyclable Ionic Media.

Coinage metals Cu, Ag, and Au are essential for modern electronics and their recycling from waste materials is becoming increasingly important to guarantee the security of their supply. Designing new sustainable and selective procedures that would substitute currently used processes is crucial. Here, we describe an unprecedented approach for the sequential dissolution of single metals from Cu, Ag, and Au mixtures using biomass-derived ionic solvents and green oxidants. First, Cu can be selectively dissolved in the presence of Ag and Au with a choline chloride/urea/H2O2 mixture, followed by the dissolution of Ag in lactic acid/H2O2. Finally, the metallic Au, which is not soluble in either solution above, is dissolved in choline chloride/urea/Oxone. Subsequently, the metals were simply and quantitatively recovered from dissolutions, and the solvents were recycled and reused. The applicability of the developed approach was demonstrated by recovering metals from electronic waste substrates such as printed circuit boards, gold fingers, and solar panels. The dissolution reactions and selectivity were explored with different analytical techniques and DFT calculations. We anticipate our approach will pave a new way for the contemporary and sustainable recycling of multi-metal waste substrates.

Sequential Selective Dissolution of Coinage Metals in Recyclable Ionic Media

AbstractCoinage metals Cu, Ag, and Au are essential for modern electronics and their recycling from waste materials is becoming increasingly important to guarantee the security of their supply. Designing new sustainable and selective procedures that would substitute currently used processes is crucial. Here, we describe an unprecedented approach for the sequential dissolution of single metals from Cu, Ag, and Au mixtures using biomass‐derived ionic solvents and green oxidants. First, Cu can be selectively dissolved in the presence of Ag and Au with a choline chloride/urea/H2O2 mixture, followed by the dissolution of Ag in lactic acid/H2O2. Finally, the metallic Au, which is not soluble in either solution above, is dissolved in choline chloride/urea/Oxone. Subsequently, the metals were simply and quantitatively recovered from dissolutions, and the solvents were recycled and reused. The applicability of the developed approach was demonstrated by recovering metals from electronic waste substrates such as printed circuit boards, gold fingers, and solar panels. The dissolution reactions and selectivity were explored with different analytical techniques and DFT calculations. We anticipate our approach will pave a new way for the contemporary and sustainable recycling of multi‐metal waste substrates.

Calculation method for a steel-reinforced concrete bridge span structure with material separation along the neutral axis

Introduction. In steel-reinforced concrete spans, the strength of reinforced concrete is not fully used due to the twostage inclusion of the cross section in the work and the irrational distribution of materials in the section. To increase the efficiency of the materials used, it is proposed to combine the steel and reinforced concrete parts along the neutral axis of the cross section. With such a cross-section design, the steel will always be in the tension zone, and the concrete in the compression zone. It is possible to implement such a design by constructing a span in one stage from prefabricated steel-reinforced concrete blocks.Materials and methods. It is possible to implement the calculation method with the separation of the material along the neutral axis when organizing the installation of the span structure in one stage, assuming that the section of the span structure operates in the elastic stage and following the laws of structural mechanics. To cover the features of the calculation of split and continuous span structures, a cantilever-beam static scheme was adopted.Results. The presented results of analytical calculations make it possible to estimate the consumption of materials in the manufacture of the span. The steel consumption of the span under study is 6.12 t/lm, the reinforced concrete consumption is 6.54 m3/lm.Installation of the span. The installation of the span is described, considering the design features.Conclusions. The optimal static layout of the span structure has been determined. A method for calculating a steel-reinforced concrete span with material separation along the neutral axis has been developed. An analytical calculation was performed to select the geometric parameters of the cross sections of the span.

Synergizing computer‐aided design, commercial software, and cutting‐edge technologies in an innovative nozzle test apparatus for an engineering laboratory course

AbstractThis study explores compressible flow, a field reliant on mathematical models for effective teaching. Using laboratory experiments as pedagogical tools, we introduce a compact nozzle test apparatus that integrates cutting‐edge technologies—additive manufacturing (AM), pressure‐sensitive paint, the Schlieren system, image processing, and computational fluid dynamics (CFD)—in a compressible flow laboratory course. Commercial software, including MATLAB, SOLIDWORKS, ANSYS Fluent, and LabVIEW, facilitates the incorporation of these technologies. The research outlines the course structure, objectives, and details of student projects. Through a comparative analysis of experimental results, analytical calculations, and CFD simulations, we showcase the successful integration of AM in pedagogical practices for compressible flow, addressing critical concerns like nozzle strength and surface roughness. Statistical data from student projects offer practical insights, ensuring accuracy in experimental applications. The laboratory's design and detailed lists of components and costs provide a meaningful comparison with a supersonic wind tunnel, considering manufacturing expenses, operational costs, spatial requirements, and noise levels. The assessment of lab report grades underscores the approach's efficacy in conveying compressible flow concepts successfully, facilitated by modern computers. In summary, our study presents a comprehensive, efficient, and technologically advanced approach to teaching compressible flow within a concise framework.

The Use of Variance Reduction Techniques for Photon Dose Estimation in the Design of Radiotherapy Facilities at 10 and 15 MeV via Monte Carlo Simulations

In the context of designing radiotherapy facilities, typical dose estimation methods involve analytical approaches, as outlined in International Atomic Energy Agency (IAEA) Safety Reports Series No. 47 (IAEA 47). These methods are known for their ease of use and rapid calculations, but they could lead to either overestimation or underestimation of radiation doses. Hence, the integration of Monte Carlo (MC) methods is considered valuable. In this particular study, a radiotherapy facility was modeled using MCNP version 6.2, and dose calculations were conducted using analytical techniques following both IAEA 47 guidelines and MC simulations. The study focused on monoenergetic photon cone beams with energies of 10 and 15 MeV. Notably, the beam’s orientation prevented primary radiation from reaching the dose location at the entrance of the maze, allowing only scatter radiation to contribute to the tally. Given the challenges associated with obtaining reliable and accurate results through standard MCNP calculations, the investigation focused on the use of weight windows as a variance reduction technique. The findings revealed that the IAEA method tends to provide conservative results only when the same conditions were replicated in the MC simulations. In fact, approximately 50% of the final dose estimated through MC methods accounted for factors that were not considered in the analytical calculations. The primary contributor to scattering (averaging around 30%) was identified as the floor and ceiling. This study underscores the need for caution when relying solely on the analytical approach, as it may not consistently yield conservative outcomes.

Clonal dynamics of surface-driven growing tissues.

The self-organization of cells into complex tissues relies on a tight coordination of cell behavior. Identifying the cellular processes driving tissue growth is key to understanding the emergence of tissue forms and devising targeted therapies for aberrant growth, such as in cancer. Inferring the mode of tissue growth, whether it is driven by cells on the surface or by cells in the bulk, is possible in cell culture experiments but difficult in most tissues in living organisms (in vivo). Genetic tracing experiments, where a subset of cells is labeled with inheritable markers, have become important experimental tools to study cell fate in vivo. Here we show that the mode of tissue growth is reflected in the size distribution of the progeny of marked cells. To this end, we derive the clone size distributions using analytical calculations in the limit of negligible cell migration and cell death, and we test our predictions with an agent-based stochastic sampling technique. We show that for surface-driven growth the clone size distribution takes a characteristic power-law form with an exponent determined by fluctuations of the tissue surface. Our results propose a possible way of determining the mode of tissue growth from genetic tracing experiments.

Elastic constants of graphane, graphyne, and graphdiyne

Graphyne (two-dimensional one-atom-thick carbon allotrope) a promising semiconductor distinct by the number of acetylenic bonds. The study of mechanical properties is of key importance for electronics, composite fabrication, and fundamental understanding of the mechanical behavior of 2D structures. Molecular dynamics and analytical calculations were used to obtain the elastic constants (stiffness and compliance constants, Young’s and shear modulus, Poisson’s ratio) for five graphynes. For the first time, the direct link between stiffness and compliance constants for 2D materials were presented. Among hexagonal graphynes, γ1 has the largest Young’s modulus (154 N/m). The deformation is attributed to the competition between the rotation and elongation of bonds in graphyne under loading. An analysis of stationary and extreme values of Young’s and shear modulus, Poisson’s ratio was carried out for the first time based on the search for the extremum of a function of one variable. A strong mechanical anisotropy was observed for orthorhombic graphynes (β3 and γ2). Orthorhombic graphynes possess extremely large in-plane Poisson’s ratio. Explanation of how elastic constants depend on structure density and atomic arrangement was given. The obtained results open new opportunities for the development of new nanomechanical devices based on such 2D materials.

Resonance behaviour of magnetoelectric (PSLZT multilayer - NZFO) layered composites: A comprehensive theory – Experimental perspective

In recent years, compact antenna and miniaturized power transfer devices are among the interesting applications of magnetoelectric (ME) composites in low frequency (LF) / very low frequency (VLF) range. Here we elucidate, in general, analytical calculations used to understand, the vibrational modes and resonance frequencies of the layered ME composite and; Finite Element Analyses (FEM) with isotropic and anisotropic properties to accurately predict the resonance frequencies pertaining to the axisymmetric and asymmetric mode of vibrations with respect to significant ME response. Further, ME coefficient of the composite with Longitudinal - Transverse (L-T) configuration based on the interface coupling model were utilized to completely study the ME composites. The configuration optimized through the design was in particular corroborated experimentally with a representative PSLZT multilayer on NZFO based ME layered composite system. The PSLZT multilayer on NZFO based ME composite was fabricated by tape casting the constituent thick films and co-sintering process which are further analysed for their ME responses at their resonance frequencies. ME voltage spectrum showed a maximum of 7.74 V/cm.Oe at its axisymmetric resonance mode at 30.6 kHz. Various peaks at different resonance frequencies with respect to axisymmetric and asymmetric modes of vibrations agree well and validates the above modeling studies. Overall, the complete study provides a systematic design guideline for optimizing the ME composite configuration suitable for specific application with required resonance frequency.

Mn single atoms coordinated with N and O and embedded in activated carbon for supercapacitor and oxygen evolution reaction applications

With the aim of increasing the potential applications of activated carbon (AC) in supercapacitors and zinc-air batteries, the present work prepared AC composites doped with Mn, N and O using various methods. These materials exhibited superior capacitive and oxygen evolution reaction (OER) electrocatalytic activity. Analytical characterizations and density functional theory calculations demonstrated that the specimen subjected to calcination and heating under N2 and NH3 (AC-Mn-3) had a higher specific surface area, an optimized distribution of pyridinic and pyrrolic N and single Mn atom active sites. These factors improved the supercapacitor performance and OER catalytic activity of this material. The hierarchical pore structure of the AC matrix also facilitated electrolyte transport while simultaneously reducing internal resistance and protecting the electrode structure during cycling. An AC-Mn-3 electrode provided a high specific capacitance of 516.20 F/g at 1 A/g while a symmetric supercapacitor based on this electrode delivered an exceptional energy density of 71.69 Wh/kg at a power density of 500 W/kg. When applied to the OER, the AC-Mn-3 achieved a low overpotential of 270.21 mV at 10 mA/cm2 in 1 M KOH. Theoretical calculations suggested that single Mn atoms coordinated with N and O effectively bound oxygenated intermediates to lower the adsorption energy barrier associated with the OER rate-determining step going from OH* to O*. These results provide new insights concerning the mechanism by which improved supercapacitor performance and OER catalytic activity can be realized and demonstrate an effective strategy for AC modification.

Analytical calculation method of circular-section rocking steel piers under horizontal cyclic load

The research object of this paper is to investigate the mechanical behavior and develop an analytical model of the prestressed circular-section rocking steel piers with external energy-dissipating devices under the horizontal cyclic load. Based on the method of monolithic beam analogy under monotonic loading, the concept of generalized rotation angle and intercept strain in the pre-decompression state was introduced. The geometrical equations for the pre- and post-decompression stages are deduced. The calculation formulas for internal forces of each component and the analytical calculation method for the entire process of the rocking steel pier under horizontal cyclic loading are established in detail. To reproduce the hysteresis curve of the test, some special test conditions, such as the retraction effect of prestressed tendons and increase of the compressed area due to the vertical plates, were considered in the analytical model. The results show that the analytical method based on generalized rotation angle and intercept strain can ensure an ideal transition of the hysteresis curve of the pier in pre- and post-decompression stages. Except for the pier with particularly severe local buckling and ovalization deformation, the calculated results obtained from the proposed analytical model agrees well with the test results for the rocking steel bridge piers. The effect of prestressed tendons and the P–Δ effect on the lateral load–displacement curve of rocking steel bridge biers was further analyzed through parametric study using the proposed model. The analytical calculation method presented in this paper provides a theoretical tool for seismic design of the rocking steel pier in engineering practice. This paper provides important guidance for the establishment of seismic design method of rocking steel piers.

Rocket science unveiled: A differential equation exploration of motion

Through the perspective of differential equations, the report "Rocket Science Unveiled" explores the amazing invention of rocket propulsion. In order to study, comprehend, and forecast the behavior of rocket engines, differential equations are essential. In order to better understand and analyze this intricate anomaly, the report aims to investigate the underlying mathematics of rocket propulsion and how differential equations work. We apply the differential equation to clarify the fuel consumption and thrust generation rates. In addition, we utilize Newton's rule of motion to explain the relationship among thrust, mass, and acceleration. Working on this study allowed us to discover the anticipated outcome for both position location and spacecraft position determination. For iterative operations, we used Euler's approach because the analytical calculation of differential equations is complicated, we used Euler's method for iterative operations. Knowing the rocket's initial or previous value allows us to locate or establish its placements with ease.

Self-consistent dynamical models with a finite extent – IV. Wendland models based on compactly supported radial basis functions

ABSTRACT We present a new step in our systematic effort to develop self-consistent dynamical models with a finite radial extent. The focus is on models with simple analytical density profiles allowing for analytical calculations of many dynamical properties. In this paper, we introduce a family of models, termed Wendland models, based on compactly supported radial basis functions. The family of models is characterized by a parameter k that controls the smoothness of the transition at the truncation radius. In the limit $k\rightarrow \infty$, the Wendland model reduces to a non-truncated model with a Gaussian density profile. For each Wendland model, the density, mass and gravitational potential are simple truncated polynomial functions of radius. Via the sphecow tool we demonstrate that all Wendland models can be supported by isotropic distribution functions. Surprisingly, the isotropic distribution function exhibits varied behaviour across different Wendland models. Additionally, each model can be supported by a continuum of Osipkov–Merritt orbital structures, ranging from radially anisotropic to completely tangential at the truncation radius. To the best of our knowledge, the Wendland models presented here are the first family of models accommodating both radial and tangential Osipkov–Merritt distribution functions. Using linear superposition, these models can easily be combined to generate Wendland models with even more diverse orbital structures. While the Wendland models are not fully representative of real dynamical systems due to their Gaussian-like density profile, this study lays important groundwork for constructing more realistic models with truncated density profiles that can be supported by a range of orbital structures.