Статті в журналах: "Penetration mechanics Mathematical models"

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B, Ofoeyeno, Achebo J.I, and Ozigagun A. "Development of Mathematical Models to Optimize Weld Penetration Area of Mild Steel in Gas Tungsten Arc Welding." International Journal of Innovative Science and Research Technology 5, no. 7 (August 5, 2020): 885–91. http://dx.doi.org/10.38124/ijisrt20jul536.

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Tungsten Inert Gas (TIG) weld quality and mechanical properties are systematically structured by the bead width, reinforcement and penetration size. This study has developed a mathematical model using the second order quadratic polynomial model to select the best setting for the process parameters to produce the maximum penetration area in TIG welding.The set of experiment samples was produced from mild steel plates guided by a central composite design experimental plan. The results obtained revealed that the second order quadratic polynomial equation is the best fit model that can accurately explain the relationship between the input and the output parameters. The results possessed good statistical sufficiency, having a very good strength for predicting the target response. The prediction strength and models reliability factor are in reasonable agreement with each other, the surface plots showed the combined interaction of input parameters on the response, and the ANOVA results revealed that the penetration area is very sensitive to the current parameter. The mathematical models developed have a high goodness of fit, adequate signal,strength which can explain and predict the penetration area

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Kim, I. S., A. Basu, and E. Siores. "Mathematical models for control of weld bead penetration in the GMAW process." International Journal of Advanced Manufacturing Technology 12, no. 6 (November 1996): 393–401. http://dx.doi.org/10.1007/bf01186927.

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Ravikumar, S. M., and P. Vijian. "Development of Mathematical Models for Prediction of Weld Bead Geometry of GTAW Stainless Steel." Applied Mechanics and Materials 867 (July 2017): 88–96. http://dx.doi.org/10.4028/www.scientific.net/amm.867.88.

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Welding input process parameters are playing a very significant role in determining the weld bead quality. The quality of the joint can be defined in terms of properties such as weld bead geometry, mechanical properties and distortion. Experiments were conducted to develop models, using a three factor, five level factorial design for 304 stainless steel as base plate with ER 308L filler wire of 1.6 mm diameter. The purpose of this study is to develop the mathematical model and compare the observed output values with predicted output values. Welding current, welding speed and nozzle to plate distance were chosen as input parameters, while depth of penetration, weld bead width, reinforcement and dilution as output parameters. The models developed have been checked for their adequacy. Confirmation experiments were also conducted and the results show that the models developed can predict the bead geometries and dilution with reasonable accuracy. The direct and interaction effect of the process parameters on bead geometry are presented in graphical form.

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O'Neill, F. G., and A. Ivanović. "The physical impact of towed demersal fishing gears on soft sediments." ICES Journal of Marine Science 73, suppl_1 (August 18, 2015): i5—i14. http://dx.doi.org/10.1093/icesjms/fsv125.

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Abstract An improved understanding of the physical interaction of towed demersal fishing gears with the seabed has been developed in recent years, and there is a clearer view of the underpinning mechanical processes that lead to the modification and alteration of the benthic environment. The physical impact of these gears on soft sediments can be classified broadly as being either geotechnical or hydrodynamic in nature: penetration and piercing of the substrate, lateral displacement of sediment, and the influence of the pressure field transmitted through the sediment can be considered geotechnical, whereas the mobilization of sediment into the water column can be considered hydrodynamic. A number of experimental and numerical approaches have been used to gain better insights of these physical processes. These include small-scale modelling in towing tanks and sand channels; large-scale modelling in the field; measurements behind full-scale towed gears at sea; numerical/mathematical modelling of sediment mechanics; and numerical/mathematical modelling of hydrodynamics. Here, we will review this research, and that in associated fields, and show how it can form the basis of predictive models of the benthic impact of trawl gears.

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Yankelevsky, DZ, VR Feldgun, and YS Karinski. "Rigid projectile penetration into a concrete medium: A new model." International Journal of Protective Structures 8, no. 3 (August 4, 2017): 473–99. http://dx.doi.org/10.1177/2041419617721542.

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A new simplified model to analyze the penetration of a rigid projectile into a concrete thick medium is presented. The concrete medium is modeled by a set of discs, responding in the radial direction under plain strain conditions. A convenient mathematical formulation is derived based on some simplifying assumptions. A major new feature of the present model is that it hybridizes two different analytical and numerical approaches that have been developed by the authors. In the present model, the Riemann problem exact solution is applied to the interaction of the projectile nose tip with the target. It is assumed that when the nose tip meets a new undisturbed disc, loading occurs during its interaction with the concrete, and therefore the unloading branch of the equation of state is not required in the Riemann problem. The other discs that maintain contact with the projectile nose and had been loaded in earlier time steps undergo unloading, and a special approach has been developed to compute their contact stresses. This entirely new formulation has not been proposed earlier. The present model enables calculations of the projectile motion time history (i.e. deceleration, velocity, and depth). Comparison of the present model results with experimental data shows very good agreement. Contrary to many other simplified models, the present approach does not require any empirical constants or any preliminary assumptions concerning the contact pressures acting on the penetrating projectile nose, as other models do. Computer time of less than 1 min is needed for a complete analysis.

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Gong, Yongping, Cheng Lin, and Kornel F. Ehmann. "Dynamics of Initial Penetration in Drilling: Part 2—Motion Models for Drill Skidding and Wandering With Experimental Verification." Journal of Manufacturing Science and Engineering 127, no. 2 (April 25, 2005): 289–97. http://dx.doi.org/10.1115/1.1852568.

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This part of the paper is aimed at the development of models for the drill tip’s transverse and angular motions, the definition of models for establishing the drilled hole’s profile and, by combining these results with the dynamic force models of Part 1, the formulation of the complete model for drill skidding and wandering. An experimental verification of the models concludes the paper. For the development of the drill motion models the drill is simplified as a pretwisted beam subjected to a compressive axial load and radial forces acting on its tip. The governing equations are developed using Hamilton’s principle. Subsequently, the weak form of the governing equation is formulated to facilitate their solution by the finite element method. The corresponding boundary conditions for the motion model are also defined for three drilling phase, i.e., drill skidding, drill wandering and stabilized drilling. Based on the drill tip’s wandering locus and drill rotation, a mathematical model for describing the drilled hole’s profile is developed.

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Moraes, Moacir Tuzzin de, Henrique Debiasi, Julio Cezar Franchini, and Vanderlei Rodrigues da Silva. "Correction of resistance to penetration by pedofunctions and a reference soil water content." Revista Brasileira de Ciência do Solo 36, no. 6 (December 2012): 1704–13. http://dx.doi.org/10.1590/s0100-06832012000600004.

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The soil penetration resistance is an important indicator of soil compaction and is strongly influenced by soil water content. The objective of this study was to develop mathematical models to normalize soil penetration resistance (SPR), using a reference value of gravimetric soil water content (U). For this purpose, SPR was determined with an impact penetrometer, in an experiment on a Dystroferric Red Latossol (Rhodic Eutrudox), at six levels of soil compaction, induced by mechanical chiseling and additional compaction by the traffic of a harvester (four, eight, 10, and 20 passes); in addition to a control treatment under no-tillage, without chiseling or additional compaction. To broaden the range of U values, SPR was evaluated in different periods. Undisturbed soil cores were sampled to quantify the soil bulk density (BD). Pedotransfer functions were generated correlating the values of U and BD to the SPR values. By these functions, the SPR was adequately corrected for all U and BD data ranges. The method requires only SPR and U as input variables in the models. However, different pedofunctions are needed according to the soil layer evaluated. After adjusting the pedotransfer functions, the differences in the soil compaction levels among the treatments, previously masked by variations of U, became detectable.

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Prasad, K. S. R., and T. R. Chari. "Some Factors Influencing Iceberg Scour Estimates." Journal of Energy Resources Technology 108, no. 3 (September 1, 1986): 234–39. http://dx.doi.org/10.1115/1.3231271.

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The phenomenon of seabed scouring by icebergs is a major threat to buried structures on the Canadian East Coast and is of immediate concern to the petroleum operators. The design of a suitable production and transportation system for the development of the Hibernia field is very much influenced by the potential size of iceberg scours. Several factors influence the theoretical estimates of scour size and some of these have been discussed in the mathematical and laboratory models proposed earlier. In this paper, an appraisal is made of the potential error in iceberg scour predictions caused by assuming a linear velocity variation during scour. The influence of an initial penetration of the iceberg prior to scour is examined. Upper and lower bounds of initial penetration depths are shown to exist which influence the resulting scour type.

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Boreiko, D. A., A. A. Lutoev, and D. Yu Serikov. "Theoretical studies on the nature and conditions of interaction of heel and peripheral nose cones of offset roller cone bits with a bottom hole." Gornye nauki i tekhnologii = Mining Science and Technology (Russia) 7, no. 3 (November 5, 2022): 231–39. http://dx.doi.org/10.17073/2500-0632-2022-3-231-239.

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An offset of roller cone rotation centerlines is used to increase the mechanical penetration rate while drilling in soft rocks. This enables increasing the area of a cutting structure teeth contact with a bottom hole. The analysis of offset cone drill bit (cutting structure) teeth wear showed that particularly significant wear is characteristic of the transition zone from the heel cone to the nose cone; which leads to significant reduction in the mechanical rate of penetration and a rapid decrease in the hole diameter. The purpose of this paper is to conduct a theoretical research on the nature and conditions of interaction between heel and peripheral nose cones of offset roller cone bits with a bottom hole; which is aimed at improving the efficiency of rock cutting by offset roller cone bits. To achieve the purpose; the authors analyzed data on the nature and causes of wear of existing offset roller cone bit cutting structure (teeth); developed a mathematical model in a cylindrical coordinate system allowing to determine the location and geometric parameters of the gage cone contact area with the hole wall for different roller cone bits sizes; developed a computer solid model for checking the adequacy of the mathematical model by comparing these two models; prepared recommendations for further improvement of the design of existing offset roller cone bit cutting structure (teeth). The research was carried out by the method of mathematical simulation of geometric figures and bodies corresponding to roller cones and a hole. The research has revealed that significant adjustments need to be made to the geometry of the roller cone teeth (currently being patented). This would allow decreasing the areas of cone heel blunting by 15–20 % as well as providing more prolonged contact of base and gage cones with bottom hole and wall surfaces. This allows to reduce wear of teeth in the transition zone of the generatrix from the peripheral nose cone to the gage (heel) cone of the roller cone and to maintain the required specific pressure on the cut rock for a longer period of time and; as a result; to increase both the mechanical penetration rate and the service life of the drilling tools.

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Fessler, H., and C. Pappalettere. "Plastic-Elastic strains in two-dimensional sections of partial-penetration fillet welds." Journal of Strain Analysis for Engineering Design 24, no. 1 (January 1, 1989): 15–21. http://dx.doi.org/10.1243/03093247v241015.

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The photoelastic coating technique was used to study plastic strains at the orthogonal intersections of plates, formed by welding two side plates, without weld preparation, to a main plate. Models were cut from this weldment, perpendicularly to the planes of the plates. These models were loaded by tension and pure bending applied to the side plates. Although yielding starts at the weld toes, it remains constrained there due to the greater strength of the heat-affected zone. Plastic collapse occurs in the ‘parent’ plate. This phenomenon is due to the heat affected zone, not due to the notch formed by the weld.

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Hough, C. L., B. Das, and T. G. Rozgonyi. "Life Models for Small-Diameter Polycrystalline Diamond Compact Bits in Hard Abrasive Media." Journal of Energy Resources Technology 108, no. 4 (December 1, 1986): 310–14. http://dx.doi.org/10.1115/1.3231282.

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Mathematical models for bit life of polycrystalline diamond compact (PDC) drill bits were developed for drilling small holes in hard abrasive media. Based on the wear-out criterion of an average 0.060 in. (1.5 mm) flank wear land, bit life equations were formulated in three forms: bit life versus rotary speed and feed rate, bit life versus rotary speed and penetration rate, and wear rate versus cutting speed and cutter engagement area. The traditional linear-logarithmic model proved inadequate to describe bit life, whereas the quadratic-logarithmic model provided the best bit life prediction equation. Consequently, it would be possible to predict the optimum economical drilling conditions more accurately by employing a quadratic-logarithmic based bit life equation. The equation demonstrated the ability to predict the bit life precisely under different modes of wear.

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Ortigara, Cícero, Moacir Tuzzin de Moraes, Henrique Debiasi, Vanderlei Rodrigues da Silva, Julio Cezar Franchini, and Felipe Bonini da Luz. "MODELING OF SOIL LOAD-BEARING CAPACITY AS A FUNCTION OF SOIL MECHANICAL RESISTANCE TO PENETRATION." Revista Brasileira de Ciência do Solo 39, no. 4 (August 2015): 1036–47. http://dx.doi.org/10.1590/01000683rbcs20140732.

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Estimation of soil load-bearing capacity from mathematical models that relate preconsolidation pressure (σp) to mechanical resistance to penetration (PR) and gravimetric soil water content (U) is important for defining strategies to prevent compaction of agricultural soils. Our objective was therefore to model the σp and compression index (CI) according to the PR (with an impact penetrometer in the field and a static penetrometer inserted at a constant rate in the laboratory) and U in a Rhodic Eutrudox. The experiment consisted of six treatments: no-tillage system (NT); NT with chiseling; and NT with additional compaction by combine traffic (passing 4, 8, 10, and 20 times). Soil bulk density, total porosity, PR (in field and laboratory measurements), U, σp, and CI values were determined in the 5.5-10.5 cm and 13.5-18.5 cm layers. Preconsolidation pressure (σp) and CI were modeled according to PR in different U. The σp increased and the CI decreased linearly with increases in the PR values. The correlations between σp and PR and PR and CI are influenced by U. From these correlations, the soil load-bearing capacity and compaction susceptibility can be estimated by PR readings evaluated in different U.

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Vaitukaitis, Povilas, Dario Maggiolo, Johan Remmelgas, Susanna Abrahmsén-Alami, Diana Bernin, Maria Siiskonen, Johan Malmqvist, Srdjan Sasic, and Gaetano Sardina. "Water transport and absorption in pharmaceutical tablets – a numerical study." Meccanica 55, no. 2 (December 16, 2019): 421–33. http://dx.doi.org/10.1007/s11012-019-01103-2.

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AbstractThe quality of a coated pharmaceutical tablet can be strongly affected by the interactions of water droplets with the porous substrate during processes such as coating process. Three different mechanisms co-exist in the coating process: water spreading, absorption and evaporation. Disentangling the fundamental understanding of these phenomena can therefore be crucial for achieving a higher quality of the products (e.g. a longer shelf-life of the tablets) and for controlling the efficiency of the process. This paper aims to investigate the spreading and absorption mechanisms after droplet impingement on a tablet using a Lattice-Boltzmann methodology. Our numerical results (droplet height and spreading, penetration depth and absorbed volume) are in a good agreement with experimental data and numerical simulations available in the literature. In particular, the spreading phase is characterised by the capillary spreading time scale, as confirmed by previous studies. In contrast to previous studies, we find that the absorption process begins at times shorter than the capillary spreading time but with a different power-law in the absorbed volume. We explain this behaviour through a modified Washburn law that takes into account three-dimensional effects. Our data can be used as a benchmark to test novel mathematical models.

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Ben-Dor, G., A. Dubinsky, and T. Elperin. "Optimization of High-Speed Penetration of Segmented Impactors Using Discrete and Continuous Models#." Mechanics Based Design of Structures and Machines 36, no. 2 (May 7, 2008): 150–68. http://dx.doi.org/10.1080/15397730801967630.

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Bazhenov, V. G., and V. L. Kotov. "Solution of problems of oblique penetration of axisymmetric projectiles into soft soil based on local interaction models." Journal of Applied Mathematics and Mechanics 74, no. 3 (January 2010): 278–85. http://dx.doi.org/10.1016/j.jappmathmech.2010.07.003.

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Донцов, Igor Dontsov, Бартенев, Ivan Bartenev, Лысыч, and Mikhail Lysych. "SIMULATION OF THE MOUNTED IMPLEMENTS MOTION WHEN TILLING DEPTH VARIATION. OSCILLATIONS MATHEMATICAL MODEL." Forestry Engineering Journal 7, no. 1 (August 15, 2017): 176–85. http://dx.doi.org/10.12737/25209.

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The main criterion of the soil cultivation quality is tilling depth. The goal is to predict the trajectory of penetration and steady tool movement as well as the trajectory when hitting an obstacle and leaving it after the obstacle was hit. Factors that actively influence the trajectory can be the tractor motion speed, geometry and weightimplement and tiller tool. For this purpose on the basis of the number of hypotheses differential equation of front and rear mounted implements vibrations is composed relative to the tractor location in a vertical plane along the axis of its movement. In the hypothesis of the force interaction of toolswith soil main provisions proposed by Professor L.V. Gyachev are developed. Mechanical models of the mounted implement are built on the basis of simplifications. In particular, the position of tool at different movement moments is determined by some predetermined function of the generalized coordinate. For the generalized coordinate a rotational angle of the lower hitch links is selected. The pointed out dependence is named as the transmission function of the hitch. By setting in the differential equations of motion various external influences and by changing the power parameters of working bodies, it is possible to imitate changes of soil medium. Such mathematical models allow to simulate movement not only within real operation conditions but that is often more important, to simulate the tools operation in conditions that in practice cannot be created. This is achieved, for example, when we set very hard and long or set very light and short tools, very hard or very soft soil, etc. So you can more clearly see the new phenomena and trends that are difficult to suppose and impossible to see in the real conditions.As a result, new solutions to traditional problems appear.

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Pasculli, A., F. Rizzo, M. Mangifesta, A. Viskovic, A. De Sanctis, G. Iezzi, V. Perrotti, A. Piattelli, and G. Aprile. "Modeling of Screw-Dental Structure Interaction: First Step Toward Finite Element Analysis." Nonlinear Phenomena in Complex Systems 23, no. 2 (July 9, 2020): 125–29. http://dx.doi.org/10.33581/1561-4085-2020-23-2-125-129.

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This research is focused on the screw-structure interaction under dynamic impulses aimed to the contact analysis of gap propagation at dental implant-abutment interface under dynamic loading. The purpose is to investigate the fracture mechanism that occurs during the screw penetration in a support and during the support vibration. Numerical Finite Element (FEM) analyses are calibrated through experimental laboratory measurements on support materials and screws typologies. Uncertainty due to the laboratory error propagation is investigated using Polynomial Chaos Expansion (PCE) of experimental measurements. The research is planned through the following steps: FEM calibration trough laboratory experiments on materials; laboratory experiments and material mechanics identification; uncertainty error propagation analysis through PCE expansion; fragility curves for numerical model calibration; FEM models calibration trough laboratory measurements on cycling loads. Therefore, the main purpose of the research activity, of which this article constitutes a preliminary and an explorative step, is to study a methodology that minimizes the local damage of the dental material due to the generation of micro-cracks following the implantation actions. Accordingly, in this paper, preliminary results are reported.

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Gianto, Rudy. "Constant Voltage Model of DFIG-Based Variable Speed Wind Turbine for Load Flow Analysis." Energies 14, no. 24 (December 18, 2021): 8549. http://dx.doi.org/10.3390/en14248549.

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At present, the penetration of wind-driven electric generators or wind power plants (WPPs) in electric power systems is getting more and more extensive. To evaluate the steady state performances of such power systems, developing a valid WPP model is therefore necessary. This paper proposes a new method in modeling the most popular type of WPP, i.e., DFIG (doubly fed induction generator)-based WPP, to be used in power system steady state load flow analysis. The proposed model is simple and derived based on the formulas that calculate turbine mechanical power and DFIG power. The main contribution of the paper is that, in contrast to the previous models where the DFIG power factor has been assumed to be constant at unity, the constant voltage model proposed in this paper allows the power factor to vary in order to keep the voltage at the desired value. Another important contribution is that the proposed model can be implemented in both sub-synchronous and super-synchronous conditions (it is to be noted that most of the previous models use two different mathematical models to represent the conditions). The case study is also presented in the present work, and the results of the study confirm the validity of the proposed DFIG model.

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Vorobyov, V. S., E. L. Karelina, O. A. Bender, and K. V. Katalymova. "STATISTICAL MODELS OF PHYSIC-MECHANICAL CHARACTERISTICS OF ROADS IN THE AREA OF CULVERTS." Vestnik SibADI 15, no. 4 (September 12, 2018): 560–73. http://dx.doi.org/10.26518/2071-7296-2018-4-560-573.

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Introduction. Increased technical requirements for roads, associated with increasing axial loads, the intensity and speed of vehicles, with the actual technical condition of the roads number, engineering structures, including culverts, activation of federal and regional services to bring the parameters of road surfaces to the world standards, all listed parameters pose the task in developing the mathematical modeling methods of physical-mechanical characteristics of soils in the culverts area. Therefore, such methods allow to reduce economic costs and time for carrying out experimental research of deformations based on the monitoring results of the soil roadbed and pavement.Materials and methods. The order of technical condition of the culverts’ research, pavement and physico-mechanical characteristics of soils, methods of experimental research were discussed in the article. Moreover, the approach to carrying out experimental works on penetration of pits in places of deformations and nearby was approved. Additionally, the evaluation of the soils condition on the roadbed and the annular space of the culverts was made.Results. The schemes of deformation and elasticity, density, humidity, consistency, plasticity number, fluidity, and physical properties of the soil are determined. The engineering-geological elements, mean values of density, humidity and compaction factor are established according to the research aim. Consequently, the values of the strain modules and the modulus of elasticity are calculated on the basis of compression and stamp tests.Discussion and conclusions. The dependence of the pavement on the physic-mechanical characteristics of the soil of the roadbed is proved. The correlation-regression analysis of soil characteristics is performed on the basis of experimental research. As a result, the regression equations are obtained in the annular space of culverts and at the distance of ± 30 m nearby. As could be proved, there are irregularities in the coverage of road clothes caused by drawdown in barrier locations. The physic-mechanical characteristics of the ground and strength characteristics are increased by culverts’ transfer on distance. The application of physic-mechanical characteristics of the soil together with experimental studies makes it possible to reduce labor costs, time and cost of testing.

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Tairidis, Georgios, Ioannis Ntintakis, Georgios Drosopoulos, Panagiotis Koutsianitis, and Georgios Stavroulakis. "Auxetic metamaterials subjected to dynamic loadings." Theoretical and Applied Mechanics, no. 00 (2022): 2. http://dx.doi.org/10.2298/tam211103002t.

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Materials with negative Poisson?s ratio are called auxetics and they present enhanced properties (e.g. damping, indentation resistance, fracture toughness and impact resistance) under external loadings. The auxetic properties are derived from peculiar-shaped microstructures, such as starshaped frames. In the present investigation, several applications are studied using auxetic microstructures. Finite element models are developed for dynamic analysis. First, an application related to auxetic microstructures, for the core of structural panels, is presented. Next, the use of auxetic materials in armor plates in dynamic bullet penetration problems is considered. Finally, a numerical simulation for wind turbines blades, with aluminum foam, polymeric foam and the proposed auxetic material is carried out. The numerical results demonstrate that the use of auxetic microstructures results in improved dynamic response of the system in comparison to conventional materials.

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Zhou, Jun, and Hai-Lung Tsai. "Porosity Formation and Prevention in Pulsed Laser Welding." Journal of Heat Transfer 129, no. 8 (September 5, 2006): 1014–24. http://dx.doi.org/10.1115/1.2724846.

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Porosity has been frequently observed in solidified, deep penetration pulsed laser welds. Porosity is detrimental to weld quality. Our previous study shows that porosity formation in laser welding is associated with the weld pool dynamics, keyhole collapse, and solidification processes. The objective of this paper is to use mathematical models to systematically investigate the transport phenomena leading to the formation of porosity and to find possible solutions to reduce or eliminate porosity formation in laser welding. The results indicate that the formation of porosity in pulsed laser welding is caused by two competing factors: one is the solidification rate of the molten metal and the other is the backfilling speed of the molten metal during the keyhole collapse process. Porosity will be formed in the final weld if the solidification rate of the molten metal exceeds the backfilling speed of liquid metal during the keyhole collapse and solidification processes. Porosity formation was found to be strongly related with the depth-to-width aspect ratio of the keyhole. The larger the ratio, the easier porosity will be formed, and the larger the size of the voids. Based on these studies, controlling the laser pulse profile is proposed to prevent/eliminate porosity formation in laser welding. Its effectiveness and limitations are demonstrated in the current studies. The model predictions are qualitatively consistent with reported experimental results.

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Haghighat, Ezzatollah, Saeed Shaikhzadeh Najar, Seyed Mohammad Etrati, and Mostafa Shamsi. "Theoretical predicting of the needle penetration force in denim fabric, part 2." International Journal of Clothing Science and Technology 27, no. 4 (August 3, 2015): 477–94. http://dx.doi.org/10.1108/ijcst-03-2014-0036.

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Purpose – The purpose of this paper is to theoretically compute and predict the needle penetration force (NPF) in woven denim fabrics with twill 3/1 weave pattern on the basis of geometrical, physical, and mechanical properties of yarns and fabric, and characteristics of sewing needle. Design/methodology/approach – To predict the NPF by mathematical relations, the proposed models by Stylios and Xu (1995) and Lomov (1998) are extended for a twill woven structure. The NPF is calculated based on resistance forces due to yarn tensile elongation, yarn resistance to bending in the near of the sewing needle while the needle penetrates into the fabric, friction between weft and warp yarns, needle profile shape, and friction between sewing needle and yarns. In order to evaluate the obtained results, nine different denim fabric samples are produced, and five sewing needles with different sizes are used. The NPF is measured on the Instron tensile tester to simulate sewing process. Findings – The results show that there is a good relationship between the predicted and experimental values of the NPF (R2=0.831, MSE=0.079, and MAPE=9.51 percent). Moreover, it is found that the performance of developed model to predict the NPF for needle sizes of 80, 90, 100, and 110 (Nm) is better than that of needle size of 120 (Nm). Generally, the developed theoretical model can predict the NPF in fabrics with twill 3/1 weave pattern. Originality/value – The fabrics with twill weave pattern have a complicated structure than plain pattern. So, in this research work, the NPF of denim fabric with twill 3/1 weave pattern was theoretically predicted on the basis of yarn elongation, changing of yarn bent shape in the near of the sewing needle, and friction between warp and weft yarns. The NPF was measured in the successive cycle loading conditions similar to sewing machine process by using a designed and constructed instrument, which is mounted on the Instron tensile tester.

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Palomar, Marta, Ricardo Belda, and Eugenio Giner. "Effect of different helmet shell configurations on the protection against head trauma." Journal of Strain Analysis for Engineering Design 54, no. 7-8 (March 21, 2019): 408–15. http://dx.doi.org/10.1177/0309324719835706.

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Head trauma following a ballistic impact in a helmeted head is assessed in this work by means of finite element models. Both the helmet and the head models employed were validated against experimental high-rate impact tests in a previous work. Four different composite ply configurations were tested on the helmet shell, and the energy absorption and the injury outcome resulting from a high-speed impact with full metal jacket bullets were computed. Results reveal that hybrid aramid–polyethylene configurations do not prevent bullet penetration at high velocities, while 16-layer aramid configurations are superior in dissipating the energy absorbed from the impact. The fabric orientation of these laminates proved to be determinant for the injury outcome, as maintaining the same orientations for all the layers led to basilar skull fractures (dangerous), while alternating orientation of the adjacent plies resulted in an undamaged skull. To the authors knowledge, no previous work in the literature has analysed numerically the influence of different stack configurations on a single combat helmet composite shell on human head trauma.

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Gorskiy, V. V., M. G. Kovalsky, and V. G. Resh. "Method of Calculating Carbon Ablation in the Jet of Liquid Rocket Engine Combustion Products." Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, no. 5 (128) (October 2019): 4–21. http://dx.doi.org/10.18698/0236-3941-2019-5-4-21.

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Nowadays carbon materials are widely used as ablating thermal protection for high-temperature structural elements in aerospace technology. Prediction of changes in the shape of the external surfaces of these elements, due to the burning of thermal protection, is closely related to the use of computational-theoretical methods describing the flow of various physicochemical and mechanical processes associated with the occurrence of the phenomenon under consideration. At the same time, it is crucial to test such methods on the results of experimental studies conducted under conditions which are implemented during the process of testing thermal protection in jets of aerodynamic units. The main elements of ablation of carbon materials include their erosion, i.e., mechanical ablation of mass, observed in high-pressure gas flows. In the process of experimental development, it is necessary to carry out research on large-scale models, which has led to widespread use of underexpanded jets of combustion products of liquid rocket engine combustion products for modeling the erosion process of thermal protection. The theoretical model of ablation of thermal protection in such jets requires taking into account the complex chemical composition of the gas mixture flowing into the model; physical and chemical interaction of this gas with thermal protection, which causes gasification of the latter; use of mathematical models describing the process of material erosion due to mechanical impact of high-pressure gas flow. The paper describes the development of the carbon material ablation calculating and theoretical methodology which could be used to determine the material erosion characteristics on the basis of solving a complex problem of circumfluence, heating, heat penetration and ablation of thermal protection.

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Ola, O. T., R. L. Valdez, K. M. Oluwasegun, O. A. Ojo, K. Chan, A. Birur, and J. Cuddy. "Process variable optimization in the cold metal transfer weld repair of aerospace ZE41A-T5 alloy using central composite design." International Journal of Advanced Manufacturing Technology 105, no. 11 (November 16, 2019): 4827–35. http://dx.doi.org/10.1007/s00170-019-04584-3.

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AbstractThe pulsed cold metal transfer (CMT+P) process was evaluated for the repair of aerospace structural components made from ZE41A-T5 magnesium alloy. The choice of welding variables was considered to be unique for the material type, weld design and geometry, and application-specific requirements. A design of experiment (DOE) method based on a rotatable 3D central composite design (CCD) was used to systematically establish relationships between independent welding variables and the resultant output variables of the CMT+P process, including the development of mathematical models based on second-order polynomial. A multiple response desirability function approach was then used for process optimization. The CMT+P process produced high-quality welds in the alloy. Welding process variables were established to produce desired weld penetration and weld reinforcement and complete fusion with minimal weld defects. Optimal domains of the independent variables were achieved; where the welds comply with the application-specific (repair of gearbox housing) requirements and acceptable class A weld quality of the aerospace fusion welding standard AWS D17.1.

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Bout, Gabriel, Diego Brito, René Gómez, Gonzalo Carvajal, and Guillermo Ramírez. "Physics-Based Observers for Measurement-While-Drilling System in Down-the-Hole Drills." Mathematics 10, no. 24 (December 18, 2022): 4814. http://dx.doi.org/10.3390/math10244814.

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Measurement While Drilling (MWD) is a technology for assessing rock mass conditions by collecting and analyzing data of mechanical drilling variables while the system operates. Nowadays, typical MWD systems rely on physical sensors directly installed on the drill rig. Sensors used in this context must be designed and conditioned for operating in harsh conditions, imposing trade-offs between the complexity, cost, and reliability of the measurement system. This paper presents a methodology for integrating physics-based observers into an MWD system as an alternative to complement or replace traditional physical sensors. The proposed observers leverage mathematical models of the drill’s electrical motor and its interaction with dynamic loads to estimate the bit speed and torque in a Down-the-Hole rig using current and voltage measurements taken from the motor power line. Experiments using data collected from four test samples with different rock strengths show a consistent correlation between the rate of penetration and specific energy derived from the observed drilling variables with the ones obtained from standardized tests of uniaxial compressive strength. The simplicity of the setup and results validate the feasibility of the proposed approach to be evaluated as an alternative to reduce the complexity and increase the reliability of MWD systems.

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Piazzullo, Daniele, Michela Costa, Luigi Allocca, Alessandro Montanaro, and Vittorio Rocco. "Schlieren and Mie scattering techniques for the ECN “spray G” characterization and 3D CFD model validation." International Journal of Numerical Methods for Heat & Fluid Flow 28, no. 2 (February 5, 2018): 498–515. http://dx.doi.org/10.1108/hff-03-2017-0120.

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Purpose This paper aims to study the heat transfer phenomenon occurring between heated walls and impinging fuel, showing the strict relationship between cooling effect after impingement and enhancing of wallfilm formation. The study focuses on a fundamental task in terms of pollutant emissions in internal combustion engines, aiming at giving a major contribution to the optimization of energy conversion systems in terms of environmental impact. Design/methodology/approach The paper is based on experimental campaigns relevant at taking measurements of an impinging spray over a heated wall in a confined vessel. The results, in both qualitative and quantitative terms (measurements of liquid and vapour radial penetration and thickness), are numerically reproduced by a computational model based on a Reynolds Averaged Navier Stokes approach, properly validated through customized sub-models. Findings The paper provides quantitative results about the agreement between radial penetration and vapour thickness between measurements and simulation, achieved by taking into account the cooling effect determined by the fuel impingement. This validation of the numerical model allows the author to give more considerations about the link between wall temperature and wallfilm formation. Originality/value This paper presents an original approach for the simulation of wall heat transfer, by imposing a boundary condition at the wall that may consider the heat conduction and temperature cooling given by fuel impingement in both lateral and normal directions. The classical Dirichlet boundary condition, characterized by imposing a fixed temperature value, is, instead, replaced by an approach based on calculating the unsteady process that couples the heat fluxes between the fluid and the solid material and within the solid itself.

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Ma, Chao-Tsung, and Zong-Hann Shi. "A Distributed Control Scheme Using SiC-Based Low Voltage Ride-Through Compensator for Wind Turbine Generators." Micromachines 13, no. 1 (December 28, 2021): 39. http://dx.doi.org/10.3390/mi13010039.

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As the penetration of renewable energy power generation, such as wind power generation, increases low voltage ride-through (LVRT), control is necessary during grid faults to support wind turbine generators (WTGs) in compensating reactive current to restore nominal grid voltages, and maintain a desired system stability. In contrast to the commonly used centralized LVRT controller, this study proposes a distributed control scheme using a LVRT compensator (LVRTC) capable of simultaneously performing reactive current compensation for doubly-fed induction generator (DFIG)-, or permanent magnet synchronous generator (PMSG)-based WTGs. The proposed LVRTC using silicon carbide (SiC)-based inverters can achieve better system efficiency, and increase system reliability. The proposed LVRTC adopts a digital control scheme and dq-axis current decoupling algorithm to realize simultaneous active/reactive power control features. Theoretical analysis, derivation of mathematical models, and design of the control scheme are initially conducted, and simulation is then performed in a computer software environment to validate the feasibility of the system. Finally, a 2 kVA small-scale hardware system with TI’s digital signal processor (DSP) as the control core is implemented for experimental verification. Results from simulation and implementation are in close agreement, and validate the feasibility and effectiveness of the proposed control scheme.

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Ochoa, Danny, Sergio Martinez, and Paul Arévalo. "Extended Simplified Electro-Mechanical Model of a Variable-Speed Wind Turbine for Grid Integration Studies: Emulation and Validation on a Microgrid Lab." Electronics 11, no. 23 (November 29, 2022): 3945. http://dx.doi.org/10.3390/electronics11233945.

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The energy transition towards renewable energies is crucial for the sustainable development of a society based on hydrocarbons. The current level of penetration and growth of wind energy in electric power systems is evident and many researchers have presented new methods for simulating and representing the electrical and mechanical characteristics of variable-speed wind turbines. However, complete mathematical models developed and implemented, for example, in MATLAB/Simulink® software, require significant computational efforts that could make grid studies impractical when its scale tends to increase. To contribute to facing this issue, this paper proposes an extended simplified model for a variable-speed wind turbine that considers the dynamic behavior of its mechanical system and includes an approximate representation of the power electronic converter. This approach broadens the scope of studies related to grid frequency control and power quality (fast-frequency response, primary frequency control, and voltage control, among others), considerably reducing the computational burden. Several validations of the proposed simplified model are presented, including comparisons with a doubly fed induction generator-based wind turbine model (phasor type) from the MATLAB/Simulink® library, and laboratory experiments under controlled conditions. The results show a good fit of the proposed simplified model to the MATLAB/Simulink® model, with minimal delays about 3% of the wind turbine inertia constant. Moreover, with the proposal, the computational time is reduced by up to 80% compared to a detailed model. This time reduction is achieved without penalizing the numerical accuracy and the estimation quality of the real behavior of the variable-speed wind turbine.

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Abbasbandy, S., and M. Mustafa. "Analytical and numerical approaches for Falkner–Skan flow of MHD Maxwell fluid using a non-Fourier heat flux model." International Journal of Numerical Methods for Heat & Fluid Flow 28, no. 7 (July 2, 2018): 1539–55. http://dx.doi.org/10.1108/hff-08-2017-0316.

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Purpose This paper aims to describe the laminar flow of Maxwell fluid past a non-isothermal rigid plate with a stream wise pressure gradient. Heat transfer mechanism is analyzed in the context of non-Fourier heat conduction featuring thermal relaxation effects. Design/methodology/approach Flow field is permeated to uniform transverse magnetic field. The governing transport equations are changed to globally similar ordinary differential equations, which are tackled analytically by homotopy analysis technique. Homotopy analysis method-Padè approach is used to accelerate the convergence of homotopy solutions. Also, numerical approximations are made by means of shooting method coupled with fifth-order Runge-Kutta method. Findings The solutions predict that fluid relaxation time has a tendency to suppress the hydrodynamic boundary layer. Also, heat penetration depth reduces for increasing values of thermal relaxation time. The general trend of wall temperature gradient appears to be similar in Fourier and Cattaneo–Christov models. Research limitations/implications An important implication of current research is that the thermal relaxation time considerably alters the temperature and surface heat flux. Originality/value Current problem even in case of Newtonian fluid has not been attempted previously.

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Burli, Anuk, Rebecca Law, and Howard Maibach. "Percutaneous Penetration: Reliability of Mathematical Models." SKIN The Journal of Cutaneous Medicine 6, no. 2 (March 4, 2022): 172–73. http://dx.doi.org/10.25251/skin.6.2.16.

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Al-Deek, Haitham M., Ayman A. Mohamed, and Essam A. Radwan. "New Model for Evaluation of Traffic Operations at Electronic Toll Collection Plazas." Transportation Research Record: Journal of the Transportation Research Board 1710, no. 1 (January 2000): 1–10. http://dx.doi.org/10.3141/1710-01.

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Traffic simulation models are used to enhance planning, design, operation, and management of transportation facilities. A discrete-event stochastic object-oriented microscopic simulation model is presented that was specifically developed to evaluate the operational performance of toll plazas. Traffic behavior is represented using a set of mathematical and logic algorithms that control the conflicts among vehicles within the toll plaza area. Modified versions of car-following and lane-changing algorithms and a new toll-lane selection algorithm are integrated into this new model to simulate traffic operation at toll plazas. The model output includes measures of effectiveness (MOEs) that can be used to evaluate the performance of existing and future individual toll lanes and the entire toll plaza system. Real-world data collected at the busiest toll plaza in the Orlando–Orange County Expressway Authority system were used to validate the developed model. Statistical tests indicate that there is no significant difference at the 95 percent confidence level between MOEs obtained from the model and those collected in the real world. Sensitivity analysis of market penetration of the electronic toll collection (ETC) system indicates that an increase in ETC subscription rate improves the efficiency of toll plaza operation. The benefits of ETC depend on the specific plaza configuration. One of the most interesting results of this study is that for all plaza configurations simulated with manual payment lanes operating over capacity, total plaza delay can be reduced by half if only 10 percent of the users switch from manual payment lanes to ETC lanes.

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33

Park, Rae-Jin, Jeong-Hwan Kim, Byungchan Yoo, Minhan Yoon, and Seungmin Jung. "Verification of Prediction Method Based on Machine Learning under Wake Effect Using Real-Time Digital Simulator." Energies 15, no. 24 (December 14, 2022): 9475. http://dx.doi.org/10.3390/en15249475.

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With the increase in the penetration rate of renewable energy sources, a machine-learning-based forecasting system has been introduced to the grid sector to improve the participation rate in the electricity market and reduce energy losses. In these studies, correlation analysis of mechanical and environmental variables, including geographical figures, is considered a crucial point to increase the prediction’s accuracy. Various models have been applied in terms of accuracy, speed calculation, and amount of data based on a mathematical model that can calculate the wake; however, it can be difficult to derive variables such as air density, roughness length, and the effect of turbulence on the structural characteristics of wind turbines. Furthermore, wake accuracy could decrease due to the excessive variables that come from the wake effect parameters. In this paper, we intend to conduct research to improve prediction accuracy by considering the wake effect of wind turbines using supervisory control and data acquisition (SCADA) data from the Dongbok wind farm. The wake divides the wind direction into four parts and then recognizes and predicts the affected wind turbine. The predicted result is the wake wind speed and its conversion to power generation by applying a power curve. We try to show the efficiency of machine learning by comparing the wake wind speed and the power generation in the wake model. This result shows the error rate using evaluation metrics of regression, such as mean squared error (MSE), root mean squared error (RMSE), and weighted absolute percentage error (WAPE), and attempts to verify power system impact and efficiency through a real-time digital simulator (RTDS).

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Zhao, Zhijun, Shuang Wang, and Jingdong Zhao. "A Penetrating-Anchoring Mathematical Model for the Soft Asteroid Anchoring System." International Journal of Aerospace Engineering 2021 (February 19, 2021): 1–10. http://dx.doi.org/10.1155/2021/8649172.

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The asteroid landing mechanism is necessary to be anchored to avoid flowing away. At present, the study on the anchoring system is mainly focused on the mechanical design, but there are few researches on the penetrating or anchoring mathematical model, and the researches on combining two models with each other are even more lacking. In the paper, based on the characteristics of Mohr-Coulomb material, a penetrating mathematical model of the anchoring system is established. This penetrating mathematical model can be used to calculate the penetrating depth of the anchor body according to the penetrating speed and the medium properties. Secondly, an anchoring mathematical model is established, which shows the relationships among the anchoring force, medium properties, and penetrating depth. Finally, a penetrating-anchoring mathematical model is built with the penetrating depth as the link. The model establishes a relationship between the anchoring force and the initial penetrating conditions.

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Park, M. H., B. J. Jin, T. J. Yun, J. S. Son, C. G. Kim, and I. S. Kim. "Control of the weld quality using welding parameters in a robotic welding process." Journal of Achievements in Materials and Manufacturing Engineering 1, no. 87 (March 1, 2018): 32–40. http://dx.doi.org/10.5604/01.3001.0012.0737.

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Purpose: Since the welding automations have widely been required for industries and engineering, the development of the predicted model has become more important for the increased demands for the automatic welding systems where a poor welding quality becomes apparent if the welding parameters are not controlled. The automated welding system must be modelling and controlling the changes in weld characteristics and produced the output that is in some way related to the change being detected as welding quality. To be acceptable a weld quality must be positioned accurately with respect to the joints, have good appearance with sufficient penetration and reduce low porosity and inclusion content. Design/methodology/approach: To achieve the objectives, two intelligent models involving the use of a neural network algorithm in arc welding process with the help of a numerical analysis program MATLAB have been developed. Findings: The results represented that welding quality was fully capable of quantifying and qualifying the welding faults. Research limitations/implications: Welding parameters in the arc welding process should be well established and categorized for development of the automatic welding system. Furthermore, typical characteristics of welding quality are the bead geometry, composition, microstructure and appearance. However, an intelligent algorithm that predicts the optimal bead geometry and accomplishes the desired mechanical properties of the weldment in the robotic GMA (Gas Metal Arc) welding should be required. The developed algorithm should expand a wide range of material thicknesses and be applicable in all welding position for arc welding process. Furthermore, the model must be available in the form of mathematical equations for the automatic welding system. Practical implications: The neural network models which called BP (Back Propagation) and LM (Levenberg-Marquardt) neural networks to predict optimal welding parameters on the required bead reinforcement area in lab joint in the robotic GMA welding process have been developed. Experimental results have been employed to find the optimal algorithm to predict bead reinforcement area by BP and LM neural networks in lab joint in the robotic GMA welding. The developed intelligent models can be estimated the optimal welding parameters on the desired bead reinforcement area and weld criteria, establish guidelines and criteria for the most effective joint design for the robotic arc welding process. Originality/value: In this study, intelligent models, which employed the neural network algorithms, one of AI (Artificial Intelligence) technologies have been developed to study the effects of welding parameters on bead reinforcement area and to predict the optimal bead reinforcement area for lab joint in the robotic GMA welding process. BP (Back Propagation) and LM (Levenberg-Marquardt) neural network algorithm have been used to develop the intelligent model.

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Lapka, Piotr, Piotr Furmanski, and Tomasz Wisniewski. "Assessment of thermal performance of protective garments." International Journal of Numerical Methods for Heat & Fluid Flow 27, no. 5 (May 2, 2017): 1078–97. http://dx.doi.org/10.1108/hff-03-2016-0101.

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Purpose The paper aims to present the advanced mathematical and numerical models of conjugated heat and mass transfer in a multi-layer protective clothing, human skin and muscle subjected to incident external radiative heat flux. Design/methodology/approach The garment was made of three layers of porous fabric separated by the air gaps, whereas in the tissue, four skin sublayers and muscle layer were distinguished. The mathematical model accounted for the coupled heat transfer by conduction and thermal radiation with the associated phase transition of the bound water in the fabric fibres and diffusion of the water vapour in the clothing layers and air gaps. The skin and muscle were modelled with two equation model which accounted for heat transfer in the tissue and arterial blood. Complex thermal and mass transfer conditions at the internal or external boundaries between the fabric layers, air gaps and skin were assumed. Special attention was paid to modelling of thermal radiation emitted by external heat source, for example, a fire, penetrating through the protective clothing and being absorbed by the skin and muscle. Findings Temporal and spatial variations of temperature in the protective garment, skin and muscle, as well as volume fractions of the water vapour and bound water in the clothing, were calculated for various intensity of incident radiative heat flux. The results of numerical simulation were used to estimate the risk of the first-, second- and third-degree burns. Research limitations/implications Because of the small thickness of the considered system in comparison to its lateral dimensions, the presented model was limited to 1D heat and moisture transfer. The convective heat transfer through the clothing was neglected. Practical implications The model may be applied for design of the new protective clothing and for assessment of thermal performance of the various types of protective garments. Additionally, the proposed approach may be used in the medicine for estimation of degree of thermal destruction of the tissue during treatment of burns. Originality/value The novel advanced thermal model of the multi-layer protective garment, skin and muscle layer was developed. For the first time, non-grey optical properties and various optical phenomena at the internal or external boundaries between the fabric layers, air gaps and skin were accounted for during simulation of thermal interactions between the external heat source (e.g. a fire), protective clothing and human skin.

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Kumari, Bharti, Anil Kumar, and Santwana Mukhopadhyay. "Investigation of harmonic plane waves: detailed analysis of recent thermoplastic model with single delay term." Mathematics and Mechanics of Solids 24, no. 3 (March 2, 2018): 828–44. http://dx.doi.org/10.1177/1081286518755232.

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This work is concerned with a recent thermoelastic model. We investigate the propagation of plane harmonic waves in the context of this very recently proposed heat conduction model, an exact heat conduction model with a single delay term, established by Quintanilla. This model attempted to reformulate the heat conduction model that takes into account microstructural effects in heat transport phenomena and provided an alternative heat conduction theory with a single delay term. We aim to study the harmonic plane waves propagating in a thermoelastic medium by employing this new model and derive the exact dispersion relation solution. We mainly focus on a longitudinal wave coupled to a thermal field and find two different modes of this wave. We derive asymptotic expressions for several important characterizations of the wave fields: phase velocity, specific loss, penetration depth, and amplitude ratio. Analytical expressions for these wave characteristics are obtained for different cases of very-high- and low-frequency regions for elastic- and thermal-mode longitudinal waves. To verify the analytical results, we also carry out computational work to obtain numerical results of the wave characterizations for intermediate values of frequency and illustrate the results graphically. We show that our analytical and numerical results are in perfect match. On the basis of the analytical and numerical results, a thorough analysis of the effects of the single delay parameter on various wave characteristics is presented. We highlight several characteristic features of the new thermoelastic model, as compared with other models.

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38

Aptukov, V. N. "Penetration: Mechanical aspects and mathematical modeling (review)." Strength of Materials 22, no. 2 (February 1990): 230–40. http://dx.doi.org/10.1007/bf00773243.

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39

Anderson Jr., Charles E. "Analytical models for penetration mechanics: A Review." International Journal of Impact Engineering 108 (October 2017): 3–26. http://dx.doi.org/10.1016/j.ijimpeng.2017.03.018.

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40

Green, W. A., and A. B. Tayler. "Mathematical Models in Applied Mechanics." Mathematical Gazette 71, no. 457 (October 1987): 241. http://dx.doi.org/10.2307/3616780.

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Tayler, A. B., and J. B. Keller. "Mathematical Models in Applied Mechanics." Journal of Applied Mechanics 55, no. 1 (March 1, 1988): 252. http://dx.doi.org/10.1115/1.3173653.

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Edwards, D. "Mathematical models in applied mechanics." Applied Mathematical Modelling 11, no. 1 (February 1987): 72. http://dx.doi.org/10.1016/0307-904x(87)90186-7.

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43

Burli, Anuk, Howard Maibach, Rebecca M. Law, Anne J. Keurentjes, and Jocelyn Rodriguez. "15438 Ability of mathematical models to predict human percutaneous penetration." Journal of the American Academy of Dermatology 83, no. 6 (December 2020): AB151. http://dx.doi.org/10.1016/j.jaad.2020.06.692.

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44

Tredenick, Eloise C., Troy W. Farrell, and W. Alison Forster. "Mathematical Modelling of Hydrophilic Ionic Fertiliser Diffusion in Plant Cuticles: Lipophilic Surfactant Effects." Plants 8, no. 7 (July 2, 2019): 202. http://dx.doi.org/10.3390/plants8070202.

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The global agricultural industry requires improved efficacy of sprays being applied to weeds and crops to increase financial returns and reduce environmental impact. Enhancing foliar penetration is one way to improve efficacy. Within the plant leaf, the cuticle is the most significant barrier to agrochemical diffusion. It has been noted that a comprehensive set of mechanisms for ionic active ingredient (AI) penetration through plant leaves with surfactants is not well defined, and oils that enhance penetration have been given little attention. The importance of a mechanistic mathematical model has been noted previously in the literature. Two mechanistic mathematical models have been previously developed by the authors, focusing on plant cuticle penetration of calcium chloride through tomato fruit cuticles. The models included ion binding and evaporation with hygroscopic water absorption, along with the ability to vary the AI concentration and type, relative humidity, and plant species. Here, we further develop these models to include lipophilic adjuvant effects, as well as the adsorption and desorption, of compounds on the cuticle surface with a novel Adaptive Competitive Langmuir model. These modifications to a penetration model provide a novel addition to the literature. We validate our theoretical model results against appropriate experimental data, discuss key sensitivities, and relate theoretical predictions to physical mechanisms. The results indicate the addition of the desorption mechanism may be one way to predict increased penetration at late times, and the sensitivity of model parameters compares well to those present in the literature.

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Bykova, A. A., and S. A. Regirer. "Mathematical models in urinary system mechanics (review)." Fluid Dynamics 40, no. 1 (January 2005): 1–19. http://dx.doi.org/10.1007/s10697-005-0039-y.

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46

Singh, Om Prakash, Mahendra Kr Singar, and Sandeep Kumar. "Mathematical Expressions Model to forecast for Chloride Ion Penetration and Comp. Strength of Recycled Coarse Aggregate Concrete Incorporating Meta-kaolin." IOP Conference Series: Materials Science and Engineering 1224, no. 1 (January 1, 2022): 012019. http://dx.doi.org/10.1088/1757-899x/1224/1/012019.

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Abstract This research investigates the mathematical modeling of compressive strength (CS) of concrete cured cube at 3, 7 & 28 days and chloride penetration resistance of cylindrical concrete specimens cured at 28 days incorporating of Meta-kaolin (MK). The experimental data results were shown various concrete specimens close to recognize compressive strength (CS) and penetration of chloride ion. Ordinary Portland cement (OPC) has been partial replacement of 0%, 5%, 8%, 12%, 16%, 18% and 20% by Meta-kaolin (MK). Compressive strength (CS) results discover through the cubes and rapid chloride penetration test (RCPT) presented. Two predictive regression models established, first for compressive strength (CS) of concrete specimen at the days of 3, 7, and 28 and second for charge passed Q at 28 days. To predictive the mathematical models have been established and have good precision, correlation by experimental results of data.

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Burli, Anuk, Rebecca M. Law, and Howard I. Maibach. "Ability of mathematical models to predict human in vivo percutaneous penetration of steroids." Regulatory Toxicology and Pharmacology 126 (November 2021): 105041. http://dx.doi.org/10.1016/j.yrtph.2021.105041.

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Kang, Youngku, and Hyo-Chol Sin. "Effective velocity range of theoretical hypervelocity penetration models." Journal of Mechanical Science and Technology 34, no. 6 (May 30, 2020): 2497–506. http://dx.doi.org/10.1007/s12206-020-0525-5.

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49

Wang, Jun, H. Liu, and Chuan Zhen Huang. "Modelling the Depth of Jet Penetration in Abrasive Waterjet Contouring of Alumina Ceramics." Materials Science Forum 471-472 (December 2004): 462–68. http://dx.doi.org/10.4028/www.scientific.net/msf.471-472.462.

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Predictive mathematical models for the depth of jet penetration are presented for both straight-slit cutting and contouring by an abrasive waterjet (AWJ). The plausibility and predictive capability of the models are assessed and verified by an experimental investigation when cutting an 87% alumina ceramic. It shows that the predictions of the models are in good agreement with the experimental data.

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50

Panyukhin, A. V., and B. N. Bad'Yanov. "Mathematical model of penetration in laser microwelding of dissimilar materials." Welding International 8, no. 5 (January 1994): 384–86. http://dx.doi.org/10.1080/09507119409548613.

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