Numerical Investigation Research Articles

Mathematical analysis of a novel fractional order vaccination model for Tuberculosis incorporating susceptible class with underlying ailment

ABSTRACT Tuberculosis (TB) is a communicable, airborne infection caused by the bacillus Mycobacterium tuberculosis. Pulmonary tuberculosis (PTB) is the most common presentation, although infection can spread anywhere to cause extra-pulmonary tuberculosis (EPTB). In this paper, a novel fractional order mathematical model is designed for the transmission dynamics of tuberculosis. Uninfected vulnerable individuals are categorized into the following: susceptible with underline ailment and susceptible without underline ailment. The research seeks to qualitatively and quantitatively analyze the proposed model and suggests comprehensive intervention measures for the control of tuberculosis among individuals with underline ailment. Some of the major highlights from the numerical investigation points out that TB vaccination is key to reducing the spread of TB among individuals with underline ailment. Furthermore, efforts to step down the spread of TB through awareness campaigns could significantly reduce the burden of the disease among individuals with co-morbidity.

Experimental and numerical investigations on the bending capacity of cold-formed steel box headers

The study investigates the bending strength of tracks of box headers beyond AISI, which considers the capacity of individual channels alone. Both experimental and FEM are used, and the results are compared to AISI. The findings highlight tracks' significant role in the overall bending capacity. AISI is found to be conservative by 34% to 152%. Failure mode is different from code theoretical expectations for a single channel. Fastener close spacing marginally improves the capacity, while side fasteners offer significant enhancement, but track widening limits this enhancement. A modification to AISI is proposed considering track strength, with outcomes showing good accuracy.

Experimental, theoretical and numerical simulation-based investigations on the fabricated Cu2ZnSn thin-film-based Schottky diodes with enhanced electron transport for solar cell

Copper-zinc-tin Cu2ZnSn (CZT) thin films are promising materials for solar cell applications. This thin film was deposited on a fluorine-doped tin oxide (FTO) using an electrochemical deposition hierarchy. X-ray diffraction of thin-film studies confirms the variation in the structural orientation of CZT on the FTO surface. As the pH of the solution is increased, the nature of the CZT thin-film aggregate changes from a fern-like leaf CZT dendrite crystal to a disk pattern. The FE-SEM surface micrograph shows the dendrite fern leaf and sharp edge disks. The 2-D diffusion limitation aggregation under slippery conditions for ternary thin films was performed for the first time. The simulation showed that by changing the diffusing species, the sticking probability was responsible for the pH-dependent morphological change. Convincingly, diffusion-limited aggregation (DLA) simulations confirm that the initial structure of copper is responsible for the final structure of the CZT thin films. An experimental simulation with pH as a controlled parameter revealed phase transition in CZT thin films. The top and back contact of Ag-CZT thin films based on Schottky behavior give a better electronic mechanism in superstrate and substrate solar cells.

Experimental and numerical investigation on thermal and hydraulic performance of semiwavy minichannels using water–ethylene glycol-based nanofluids

Experimental and numerical investigation on thermal and hydraulic performance of semiwavy minichannels using water–ethylene glycol-based nanofluids

Elucidation of the “jumping and dropping” phenomena of piezoelectric vibrators in high-amplitude operation in the vicinity of their mechanical resonance frequencies

Abstract The peculiar events called the “jumping and dropping” phenomena of piezoelectric ceramic vibrators in high amplitude operation have widely been known. The phenomena, which occur solely in the vicinity of the mechanical resonance frequencies of the vibrators, are the emergence of hysteresis in frequency domain with abrupt increase and decrease of the vibratory amplitude. It has long been believed that the nonlinearity of the piezoelectric materials is the dominant cause of the unstable vibratory behaviors. Nevertheless, the authors have found that they can be attributed to the local piezoelectric polarization reversals due to the electric field concentration caused by its conspicuous distortion inside the vibrators in mechanical resonance. This hypothesis has been examined by numerical and experimental investigations for hard-type piezoelectric ceramic disks vibrating in axisymmetric radially pulsating mode.

The volume fraction of nanoparticles and temperature effects on thermal conductivity of SWCNT–Fe3O4–CuO/ethylene glycol–water ternary hybrid nanofluid: experimental, numerical, and statistical investigations

The volume fraction of nanoparticles and temperature effects on thermal conductivity of SWCNT–Fe3O4–CuO/ethylene glycol–water ternary hybrid nanofluid: experimental, numerical, and statistical investigations

Chronoamperometric response of electrochemical reaction diffusion system: a new theoretical and numerical investigation for EC2 scheme

Chronoamperometric response of electrochemical reaction diffusion system: a new theoretical and numerical investigation for EC2 scheme

Numerical investigation of thermal damage in rocks under high‐voltage electric pulse

Numerical investigation of thermal damage in rocks under high‐voltage electric pulse

Experimental and numerical investigations of secondary granular flow

Experimental and numerical investigations of secondary granular flow

Numerical Investigation of Reinforced Concrete (RC) Columns Strengthened with Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC) Jackets

The strengthening of existing columns using additional reinforced concrete (RC) jackets is one of the most popular techniques for the enhancement of a column’s stiffness, load-bearing capacity and ductility. Important parameters affecting the effectiveness of this method are the strength of the additional concrete, concrete shrinkage and the connection between the old and the new concrete. In this study, the application of Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC) jackets for the structural upgrade of RC columns has been examined. Extensive numerical studies have been conducted to evaluate the effect of parameters such as the thickness of the jacket, concrete shrinkage and the addition of steel bars, and comparisons have been made with conventional RC jackets. The results of this study indicate that the use of UHPFRC can considerably improve the strength and the stiffness of existing reinforced concrete columns. The combination of UHPFRC and steel bars in the jacket leads to the most effective strengthening technique as a significant enhancement in the stiffness and the ultimate load capacity has been achieved.

Numerical investigation of slip effects on heat and mass transfer in a vertical channel with immiscible micropolar and viscous fluids of variable viscosity

AbstractThis study investigates the fluid flow, heat, and mass transfer phenomena within a vertical channel containing two immiscible fluids, with a particular focus on slip effects. These effects include no slip, velocity slip, thermal slip, and multiple slips, each analyzed with appropriate boundary conditions. The study thoroughly examines key characteristics, such as variations in thermal conductivity and viscosity. Using a sixth‐order Runge–Kutta numerical method implemented using Mathematica, the study achieves precise solutions for complex scenarios. The detailed results show how the various slip mechanisms and relevant parameters interact with each other in complex ways. These findings are useful for both theoretical understanding and application in real‐life engineering situations. This study also gives important information about how fluid flow, heat transfer, and mass transfer change under different slip effects. It looks at these effects and shows how they change visually. It also carefully calculates and analyzes engineering parameters like the Nusselt number, shear stress, and Sherwood number using bar charts, showing how they affect and behave. The study resulted in velocity slip having a minimal impact on temperature, whereas thermal slip resulted in higher temperatures. Both velocity and thermal slip conditions simultaneously result in the lowest temperatures.

Combined effect of graphene oxide and fly ash on behaviour of high-strength concrete: experimental and numerical investigation

Combined effect of graphene oxide and fly ash on behaviour of high-strength concrete: experimental and numerical investigation

Impact resistance performance of precast reinforced concrete barriers with grouted sleeve and steel angle-to-plate connections

This study presents the experimental and numerical investigations on the impact resistance of precast reinforced concrete (RC) barriers with grouted sleeve and steel angle-to-plate connections. Four full-sized precast RC barriers were prepared and tested using the pendulum impact facility. Three main parameters, including spacing of grouted sleeves, number of steel angle-to-plate connections and impact energy, were considered in the tests. The failure mode, impact force and lateral deflection of barriers were recorded and analyzed. Under impact loading, the spider-web-like cracks mainly occurred on the rear surface of the barrier, and the presence of the grout sleeve and steel angle-to-plate connections ensured strong anchoring. Additionally, finite element (FE) model was established and calibrated with the test results. With the calibrated models, the dynamic motion process, distributions of stress and strain, and energy absorption of precast RC barrier were analyzed and compared with the cast-in-place barrier. Finally, the influences of impactor mass, impact velocity, grouted sleeve spacing, and steel angle-to-plate connection spacing on the impact resistance were evaluated in the parametric analysis.

Influence of section profiles on flexural behavior of unsymmetrical cold formed steel sections – analytical and numerical investigation

Influence of section profiles on flexural behavior of unsymmetrical cold formed steel sections – analytical and numerical investigation

Generative design framework for RC deep beams using topology optimization and generative tie method: Experimental and numerical investigation

This research paper proposes a generative design framework that combines topology optimization and the Generative Tie Method (GTM). The study explores the design and performance evaluation of structural concrete deep beams using this framework. A comprehensive investigation involving computational simulations and rigorous large-scale experimental testing provides insights into the optimization strategies of structural concrete deep beams. Specimens designed in accordance with the proposed framework, with an allowable value of compressive strength reduction in concrete (ηadm) set to 0.7, exhibited lower ductility ratios compared to specimens designed with ηadm equal to 0.5. Ductility ratio losses varied significantly, ranging from 28.2 % to 66.2 % among specimens subject to the same optimization level. The topology optimization process significantly influenced stress distribution, cracking behavior, and overall ductility. The Global Warming Potential factor is employed to assess the environmental impact of the optimized structural members. Comparative analyses between the proposed design methodology and a traditional method demonstrate several advantages, including greater material efficiency, higher ductility, and reduced environmental impact. However, the framework demands advanced tools, expertise, and additional training for practical application.

Numerical Investigation on the Thermo-Mechanical Response of Geothermal Energy Pile in East Indian Climatic Condition

Numerical Investigation on the Thermo-Mechanical Response of Geothermal Energy Pile in East Indian Climatic Condition

Structural behaviour and design of cold-formed austenitic stainless steel flat-oval hollow section beam-columns

This paper presents experimental and numerical investigations into the global buckling behaviour and resistances of cold-formed austenitic stainless steel flat-oval hollow section beam-columns under combined compression and bending. A testing programme, including initial geometric imperfection measurements and ten beam-column tests about the cross-section major and minor principal axes, was firstly conducted. The key obtained test results, including failure loads, load–deformation histories and failure modes, were reported. Following the testing programme, a numerical modelling programme was performed, with finite element models developed to simulate the beam-column test results and then used to conduct parametric studies for generating additional numerical data. Then, the applicability of relevant codified design interaction curves to cold-formed austenitic stainless steel flat-oval hollow section beam-columns was evaluated based on the test and numerical data. The evaluation results revealed that the design interaction curve of the American specification resulted in an overall good level of design accuracy and consistency, while the design interaction curve of the European code led to slightly conservative resistance predictions, mainly due to the conservative bending end point. To address this shortcoming, a revised Eurocode design interaction curve with an improved bending end point was proposed and shown to provide more accurate resistance predictions for cold-formed austenitic stainless steel flat-oval hollow section beam-columns than the original Eurocode design interaction curve.

Post-fire behavior and residual resistances of S890 ultra-high strength steel circular hollow sections under combined compression and bending

This paper presents experimental and numerical investigations into the post-fire local buckling behavior and residual resistances of S890 ultra-high strength steel (UHSS) circular hollow section (CHS) under combined compression and bending. The physical testing was firstly conducted and encompassed heating, soaking and cooling of specimens, as well as post-fire tensile coupon tests, measurements of initial local geometric imperfections and eccentrically loaded stub column tests. Then, finite element models were developed and validated with reference to the experimental observations and then adopted for parametric analyses to derive additional numerical data, considering various cross-section dimensions and loading combinations. As a result of the lack of design provisions for ultra-high strength steel structures after exposure to elevated temperatures, the applicability of the relevant ambient temperature design interactive curves given in the current European, American and Australian standards to post-fire S890 UHSS CHS under combined compression and bending was assessed, with post-fire material properties used. The assessment results showed that all design standards exhibited conservative and scattered predictions of residual resistances for S890 UHSS CHS under combined compression and bending at ambient temperature and after exposure to elevated temperatures. The American specification provided more precise predictions of residual failure loads for non-compact and slender (Class 3 and 4) sections than the Eurocode and Australian standard, due to the accurate compression and bending endpoints. In comparison to the American and Australian specifications, the Eurocode resulted in more precise results in predicting residual failure loads of compact (Class 1 and 2) sections, owing to the accurate compression and bending endpoints as well as the nonlinear design interaction curve.

Modelling and simulation of natural hydraulic fracturing applied to experiments on natural sandstone cores

AbstractUnder in-situ conditions, natural hydraulic fractures (NHF) can occur in permeable rock structures as a result of a rapid decrease of pore water accompanied by a local pressure regression. Obviously, these phenomena are of great interest for the geo-engineering community, as for instance in the framework of mining technologies. Compared to induced hydraulic fractures, NHF do not evolve under an increasing pore pressure resulting from pressing a fracking fluid in the underground but occur and evolve under local pore-pressure reductions resulting in tensile stresses in the rock material. The present contribution concerns the question under what quantitative circumstances NHF emerge and evolve. By this means, the novelty of this article results from the combination of numerical investigations based on the Theory of Porous Media with a tailored experimental protocol applied to saturated porous sandstone cylinders. The numerical investigations include both pre-existing and evolving fractures described by use of an embedded phase-field fracture model. Based on this procedure, representative mechanical and hydraulic loading scenarios are simulated that are in line with experimental investigations on low-permeable sandstone cylinders accomplished in the Porous Media Lab of the University of Stuttgart. The values of two parameters, the hydraulic conductivity of the sandstone and the critical energy release rate of the fracture model, have turned out essential for the occurrence of tensile fractures in the sandstone cores, where the latter is quantitatively estimated by a comparison of experimental and numerical results. This parameter can be taken as reference for further studies of in-situ NHF phenomena and experimental results.

Numerical investigation of combustion characteristics of extended coherent flame model 3 zones (ECFM‐3Z) in diesel engines running with biodiesel

AbstractThis research investigates the application of Extended Coherent Flame Model‐3 Zones (ECFM‐3Z) to assess the performance and emissions of rapeseed oil methyl ester (ROME). Experimental tests were carried out using a Lombardini 3 LD 350 model single‐cylinder diesel engine, at 1600–3000 rpm with 200 rpm speed increments, under full load conditions. For numerical analysis, STAR‐CD/ESICE software was employed. Methyl Oleate (C19H36O2) was predicted as the surrogate biodiesel based on Gas Chromatography (GC) analysis and average mass calculation. Notably, the numerical analysis revealed a remarkable similarity in brake power between the experimental and computational investigations. In the range of 2400–3000 rpm, the biodiesel's performance exhibited a maximum deviation of 5%, primarily attributed to pumping, thermal, and friction losses. In terms of emissions, carbon dioxide (CO2) emissions were consistent with the findings of the experimental study, with a maximum disparity of 10%. However, carbon monoxide (CO) emissions ranged from 57% to 65% lower than those observed in the experimental study, while nitrogen oxide (NOx) emissions exhibited a reduction of 63% to 84%. In contrast, oxygen (O2) emissions were notably higher, ranging from 93% to 117% compared to the experimental study, and exhaust temperatures were elevated by 33% to 49% in comparison to the experimental results.