Perforated Sheet Research Articles

Computational analysis of the steam-water flow through a submerged perforated sheet

Computational analysis of the steam-water flow through a submerged perforated sheet

تأثير عوامل التشغيل على جودة الضرب لألرز طويل الحبة

The current study aimed to test and evaluate sheets’ different perforation shapes, brake angles, and milling durations to improve the quality of long-grain white rice from an abrasive milling machine. The investigated parameters of head rice yield, broken rice percentage, whitening degree, and rice bulk temperature were influenced by five sheets with five perforated shapes (horizontal, vertical, inclined, 1 mm round holes, and 1.5 mm round holes), three brake angles (0, 45, and 90º), and four milling durations (60, 70, 80, and 90 s). The results showed that the horizontal rectangular perforated sheet resulted in the highest value of head rice yield and the lowest value of broken rice. On the other hand, the vertical rectangular perforated sheet resulted in the highest whitening degree, followed by the inclined rectangular perforated sheet. The round holes (1.0 mm and 1.5 mm diameter) are not recommended for the long-grain whitening process because of the resulting high values of broken kernels, rice bulk temperature after the whitening process, and lower values of whitening degree. The brake angle of 90º resulted in the highest value of broken rice for all studied perforated sheets used in this study. This study recommended that the optimum operating conditions were using the horizontal rectangular perforated sheet, zero degree brake angle and milling duration of 80 s.

Studies on Performance Parameters for Development of Finger Millet Thresher

Aims: To study about the design parameters and optimizations of the performance parameters for the finger millet thresher development.
 Study Design: Development of prototype to test the design parameters and optimization through experiments.
 Place and Duration of Study: Department of Farm Machinery and Power Engineering, Swami Vivekanand College of Agricultural Engineering and Technology and Research Station, Indira Gandhi Krishi Vishwavidyalaya, Raipur, between September 2021 to April 2022. 
 Methodology: A prototype was developed which consisted of threshing drum, concave unit and reciprocating sieve unit. A study was conducted by taking four feed rate (120, 150, 180 and 210kg/h), four types of threshing cylinder (peg type, canvas type, combination of peg and canvas type and flail type) along with three types of concave (bar type, perforated sheet and combination of both) to find out the optimized threshing parameters for finger millet. The statistical analysis was carried out by three factor randomised block design with the three replications. The various performance parameters were also calculated.
 Results: The result showed that the maximum threshing efficiency (97.25%), cleaning efficiency (99.25%), total broken percentage (2.08%) and threshing capacity (121.5kg/h) were observed with 180 kg feed rate, combination of peg and canvas type of threshing cylinder, combination of bar and perforated sheet type concave.
 Conclusion: It was concluded that combination of peg and canvas type threshing cylinder works better compared to other and gives a combination of impact and rubbing action. This impact and rubbing action can be used to develop a thresher for such crop which needs impact with rubbing such as finger millet.

Implementasi Teknik Steganografi Menggunakan Algoritma Cardan Grille

Data security and confidentiality is an activity that aims to secure data, especially data that is confidential and important. If there is a break-in and theft of information of an important data in a file, it will be detrimental to the parties concerned. Therefore it takes Steganography technique is a technique that can hide messages or confidential information into other messages so that other people are not aware of the existence of the message to be hidden. In this study, the authors build a text data security system using the Cardan Grille Algorithm. whose main function is to hide messages, not to encrypt messages, so Cardan Grille is more often used for steganography. To do Cardan Grille, you need a perforated sheet and in the holes will be filled with letters, which are filled with letters, which are filled with messages and after that the sheet will be lifted and filled with the remaining sentences.

Experimental vs. Numerical Computation of Acoustic Analyses on the Thickness Influence of the Multilayer Panel

Sound-absorbing panels made with a perforated front and a sound-absorbing material on the back have been used in many forms of construction for a long time. It is a reasonably efficient system, obtaining high values of sound absorption at a specific resonant frequency, depending on the design of the structure of the sound-absorbing multilayer panel. The present work considers an acoustic panel in two constructive types, consisting of four layers: a front panel made of perforated sheet, polyethylene foam foil, basalt wool board with two different thicknesses, and a back panel of the non-perforated sheet. Due to the different thicknesses of the basalt wool board, for the multilayer structure of the acoustic panel, differences in acoustic impedance and acoustic absorption can be highlighted, experimentally determined with an impedance tube, using the transfer function method (TFM) based on EN ISO 10534-2 in the frequency range 100–3200 Hz. In the meantime, a method was developed to predict the sound absorption coefficient, namely the prediction of sound absorption coefficient using the transfer matrix method (PSAC-TMM). This computational model of the multilayer acoustic panel is introduced considering the internal geometry of the multilayer panel, as well as the computation of the acoustic impedance of each layer, all gathered through the transfer matrix method (TMM). Comparative analyses between experimental data and predictive results using PSAC-TMM were performed, validating the PSAC-TMM as a predictive method to estimate the sound absorption coefficient for acoustic multilayer panels.

Boosting the performance of Zn-air cells by spinel catalysts with bimodal pore structure and gill filament configuration

Spinel oxides with specific morphology are importantly multifunctional materials for various applications. Here we report various morphological spinel oxides with one and two-modal pore size structures. The surface microstructure, phase composition, specific surface areas and electrocatalytic OER/ORR activities are examined. The results reveal that the bicomponent (NiCo2O4 and Co3O4) spinel exhibits a bimodal pore size distribution, high specific surface area, good OER activity (an overpotential of 313 mV at 10 mA cm−2Geo) and low Tafel slope of 73.1 mV dec−1. The Co3O4 component presents a perforated sheet morphology similar to an ancient window configuration with regular hole patterns, which benefits for mass transfer and O2 bubble detachment. By comparison, the single-component NiCo2O4 spinel having the morphology of more open self-assembled nanoneedle spheres or nanorod clusters, similar to the configuration of fish gill filaments, shows better ORR activities. The morphology, similar to the fish gills, can readily capture dissolved oxygen molecules from the film electrolyte at the three-phase interface and improve ORR performance. In addition, calcination temperatures also significantly affect pore structure, surface areas, and electrocatalytic activities. Finally, small Lab size Zn-air cells are assembled using thin flexible air electrodes with the self-assembled nanoneedle NiCo2O4 catalysts. Electrochemical charging-discharging performance and cycling durability are evaluated.

Comparing the performance of four shading strategies based on a multi-objective genetic algorithm: A case study in a university library

Through the control of excessive daylight in buildings, shading devices can reduce glare and improve occupants' visual comfort. However, shading devices may overly reduce illuminance levels. Many shading strategies are available, but they do not perform equally well, and traditionally, it has been difficult to select the most suitable shading strategy. This study proposed a parameterization method for the selection and design of a shading strategy that would reduce glare while maintaining a satisfactory daylighting level, through the construction of Pareto sets based on a multi-objective genetic algorithm. The objective function was created by combining a dynamic glare evaluation indicator, the spatial glare autonomy (sGA), and a self-constructed daylight index, the spatial daylight vote autonomy (sDVA), developed from a field survey. As a case study, the proposed method was used to compare the performance of four shading strategies, including vertical slats (Vs), a perforated aluminum sheet (PAS), serrated windows with southern orientation (Sw_S), and serrated windows with northern orientation (Sw_N) in a university library in Shanghai, China. It was found that the Sw_S and PAS had a relatively bad performance; the Vs performed better than the Sw_N in providing a more satisfactory illuminance level; and the Sw_N was more effective in reducing the glare. The multi-objective optimization process can be used to obtain near-optimal design parameters that create a visual environment with reduced glare while maintaining an acceptable illuminance level, for all four shading strategies. The developed method can be a helpful tool in the design of an appropriate daylighting environment.

Research on Single Point Incremental Forming Characteristics of Perforated TA1 Sheet

In view of its high compactibility, flexibility, reduced compacting pressure, and other superiorities, the single point incremental forming (SPIF) technique has been applied increasingly in the cranial prosthesis forming of perforated TA1 sheet with irregular surface features. Whereas the SPIF of perforated sheet, which seems to meet many challenges in the biomedicine field, where control of component geometric dimensions are qualification requirements of cranial prosthesis. The mechanism of incremental forming and characteristics of perforated TA1 sheet become more complicated because of the mesh apertures. Hence, certain path and forming technique parameters were set to conduct finite element modelling on the truncated right angle cone components of perforated TA1 sheet and titanium plate respectively on the basis of the ANSYS/LS-DYNA platforms, in light of the constructed model, the distribution and variation law of displacement field coupled with the contour accuracy, wall thickness, and strain capacity for different areas of components in the forming process were obtained by researches, bringing up to light the forming mechanism of conical perforated TA1 sheet components. The research findings indicate that the aperture structure of perforated TA1 sheet allows the material elements to accomplish deformation in the surface where the aperture is located, and the strain rate and radial aperture growth rate of perforated titanium sheet are relatively high, the maximum radial aperture growth rate value is as high as 78.53 percent, the maximum circumferential aperture growth rate value is only 10.84 percent, the extension-thinning of forming section for perforated TA1 sheet is higher than that of the titanium plate, and perforated TA1 sheet possesses higher geometric accuracy than titanium plate.

Validation of the STEG code using experiments on Two-Phase flow across horizontal tube bundles

The results of the validation of the STEG code using the experiments on two-phase flow across horizontal tube bundles are presented. The experiments are carried out on two water–air SG models, consisting of a transparent vessels, inside of which there is a tube bundle, a perforated sheet and a bead separating the upstream section of the circulation circuit of the model from the downstream one. The void fractions and water velocities are measured in different locations of the models. The brief description of the STEG code based on the 3D two-fluid model is presented. A set of interfacial drag correlations, which was recently developed by the authors, are used in the validation calculations. The peculiarities of the spatial two-phase flows have been established, and a quantitative comparison with experimental data has been performed. Good agreement between the calculated and experimental data is obtained. About 90% of the experimental data points for both void fraction and water velocity are predicted by the STEG code with an accuracy of 10%.

MHD Casson fluid flow with Navier's and second order slip due to a perforated stretching or shrinking sheet.

The present work discusses the laminar boundary layer flow of an electrically conducting Casson fluid due to a horizontal perforated sheet undergoing linear shrinking/stretching with mass transpiration. Navier's slip and second-order slip conditions are also imposed on the flow. The system is subjected to a transverse magnetic field. The non-Newtonian flow under consideration obeys the rheological equation of state due to the Casson model. The PDEs governing the bounder layer flow is reduced to a nonlinear boundary value problem in ODEs by utilizing appropriate similarity transformations and are expressed analytically. The similarity solution is found to be a function of the Casson parameter, magnetic parameter, mass suction/injection parameter, and the first/second-order slip parameters. Such a solution is either unique, or dual solutions exist in a region defined by the mass transfer induced slip parameter. The results of the present work are found to be an increase of the magnetic effects resulting in expansion of the unique solution region and contraction of the dual solution region for the flow due to the induced Lorentz force. In the unique solution region, an increase in magnitudes of mass suction induced slip and the first/second-order slip parameters result in a reduction of the wall shear stress in the shrinking sheet, while the wall shear stress with mass suction increases with the Casson and the magnetic effects. Similar results exist for the stretching sheet case with mass suction. However, only unique similarity solutions exist only for the case of stretching sheets with mass injection. The current work is a generalization of the classical works of Crane (1970) and Pavlov (1974) for a stretching sheet. Mass suction/injection induced slip enhances and achieves a dominant flow driven by reversing the flow direction of the moving sheet, which allows an adjacent flow against the sheet. The findings have possible industrial applications in fluid-based systems including stretchable/shrinkable things, automated cooling systems, power generation, microelectronics, and present new results to the problem.

PM 3/66 (3) Guidelines for the management of plant health risks of biowaste of plant origin

<scp>PM</scp> 3/66 (3) Guidelines for the management of plant health risks of biowaste of plant origin

Effect of conical air distributors on drying of peppercorns in a fluidized bed dryer: Prediction using an artificial neural network

The effect of conical air distributors on the drying of peppercorns in a fluidized bed dryer was experimentally studied. A flat perforated sheet was installed in the column at the base of the bed. Conical air distributors consisted of two parts. The first was a solid cone located below an air duct, while the second part was a perforated metal cone placed on the flat perforated sheet. Experiments were carried out using perforated metal cones with three different height to base diameter ratios, ( h/H ) values of 0.5, 1.0, and 1.5 and three different air velocities, 1.2 U mf , 1.6 U mf , and 2.0 U mf . An air distributor, consisting of a solid cone and a perforated metal cone with h/H = 1.0 and an air velocity of 2.0 U mf , showed the best drying performance. It was also discovered that increasing the air velocity accelerated the drying process. A neural network was created to predict the moisture content of peppercorns during the drying process. The split, sample type, spilt ratio, momentum, and learning rate, as well as the numbers of hidden layers, hidden nodes, and training cycles all had an impact. A maximum coefficient of determination of 0.996 was found for the best model.

Comparison of Daylight Performance in Three Different Sky Conditions for Various Window Shading Types

Building sector contributes 40% of total energy consumption. In line with this, passive design strategy should be taken as an essential consideration to bring occupants comfort both thermally and visually. Besides, related to human health, one of the factors that the designer is encouraged to fulfill is the proportional amount of daylight that penetrates the building’s room. The passive strategy to optimize the daylight performance can be approached both from the building orientation and the shading system. This paper will computationally compare the different shading systems from vertical and horizontal louver, perforated metal sheets, and expanded metal shading, aiming to investigate the desirable shading-related design solution for the given condition. The simulated room is virtually situated in three different sun positions: Birmingham, United Kingdom, Jakarta, Indonesia, and Sydney, Australia. The metrics used in this experiment are Useful Daylight Illuminance (UDI). The Rhinoceros and Grasshopper were used to model the intended simulated room, while Ladybug and Honeybee were used to undergo environmental analysis. The results show that the vertical louver LV performs better in the three regions than the rest three compared shading. The experiment results are expected to give an overview which of which is fit for the situation.

Fracture Mechanism and Residual Strength on Aluminum Alloy Perforated Sheets

Fracture Mechanism and Residual Strength on Aluminum Alloy Perforated Sheets

Magnetospectroscopy of terahertz surface plasmons in subwavelength perforated superlattice thin-films

Surface plasmons, the resonant oscillations of conducting electrons at the interface of negative and positive permittivity materials, pave the way for enhanced electromagnetic wave–matter interactions at a subwavelength scale. On the other hand, spin-dependent magnetotransport ushers an ingenious technology by inculcating electron spin to realize miniaturized, energy-efficient electromagnetic devices. Generally, magneto-resistive devices (viz., multilayer un-patterned magnetic–non-magnetic thin films) relying on magnetotransport mechanisms are not recognized for supporting surface plasmons toward enhanced electromagnetic interactions. However, an amalgamation of surface plasmons with spin-dependent magnetotransport can exploit magnetic (spintronic) degree of freedom in plasmonic devices. In this work, we propose a patterned superlattice (non-magnetic/ferromagnetic thin films) terahertz (THz) magneto-resistive device for supporting surface plasmons toward enhanced electromagnetic interactions. Magnetotransport dependent enhancement and dynamic magnetic modulation of resonant THz transmissions are experimentally demonstrated in subwavelength superlattice (Al/Ni) hole arrays for varying lattice parameters. Our experiments reveal that typical non-magnetic electromagnetic phenomena like surface plasmon resonances can be tweaked by externally applied low intensity magnetic fields [∼few tens of milli-tesla (0–30 mT)]. Experimental outcomes are explicated by spin-dependent terahertz magnetotransport theory in perforated superlattice metal sheets and, therefore, can stimulate a paragon for spin-based integrated photonic technology.

Mechanical characterization of double-skin perforated-sheet façades

The need to reduce energy consumption and related CO2 emissions within buildings requires further in-depth analysis of buildings and their components. Building envelope materials are crucial in that regard. One example is the double-skin façade, a passive energy saving alternative, the various advantages of which include increased acoustic protection, natural lighting, natural ventilation, and user comfort. This type of system can employ lightweight perforated steel or aluminium sheets, that are industrially manufactured. The metal frames in which the sheets are fixed withstand deformation due to wind forces that the perforated sheets alone might otherwise not withstand. In this research, the mechanical behaviour of the perforated sheets is analyzed to establish whether the use of frames is necessary and to determine, through experiments on sheet size materials and thicknesses, the optimal fold dimensions of the sheets to withstand deformation in the absence of frames. To do so, the sheets underwent Finite Element Method (FEM) modelling and laboratory testing, the results of which were carefully analyzed. The performance of the steel sheets was observably better than the thinner aluminium sheets. The sensitivity of the perforated sheets and their behaviour could be observed when the fold supports were attached to the inner structure.

Tunable Orientation and Assembly of Polymer-Grafted Nanocubes at Fluid–Fluid Interfaces

Self-assembly of faceted nanoparticles is a promising route for fabricating nanomaterials; however, achieving low-dimensional assemblies of particles with tunable orientations is challenging. Here, we demonstrate that trapping surface-functionalized faceted nanoparticles at fluid-fluid interfaces is a viable approach for controlling particle orientation and facilitating their assembly into unique one- and two-dimensional superstructures. Using molecular dynamics simulations of polymer-grafted nanocubes in a polymer bilayer along with a particle-orientation classification method we developed, we show that the nanocubes can be induced into face-up, edge-up, or vertex-up orientations by tuning the graft density and differences in their miscibility with the two polymer layers. The orientational preference of the nanocubes is found to be governed by an interplay between the interfacial area occluded by the particle, the difference in interactions of the grafts with the two layers, and the stretching and intercalation of grafts at the interface. The resulting orientationally constrained nanocubes are then shown to assemble into a variety of unusual architectures, such as rectilinear strings, close-packed sheets, bilayer ribbons, and perforated sheets, which are difficult to obtain using other assembly methods. Our work thus demonstrates a versatile strategy for assembling freestanding arrays of faceted nanoparticles with possible applications in plasmonics, optics, catalysis, and membranes, where precise control over particle orientation and position is required.

Three-layer phase-field model of finite strain shell for simulating quasi-static and dynamic fracture of elasto-plastic materials

Shell structures are widely used in the aerospace, automobile, pipeline, and construction industries. Under quasi-static and dynamic loading, the failure modes of the thin and thick shells are quite different. To explain the correct fracture behavior of the moderated thick shell under bending loads, this paper proposed a new three-layer phase-field model for elasto-plastic materials based on the crack regularized phase-field model. Three independent phase-fields corresponding to the shell’s upper, middle, and lower surfaces are used. This provides a realistic behavior in bending-dominated problems, which is illustrated in the classical beam and plate problems. Five typical numerical examples are given, including the bending of bi-clamped beam, the Muscat-Fenech and Atkins plate problem, the dynamic crack growth problem in a stiffened cylinder under internal pressure, the radial cracks problem in perforated sheets, and the circular steel plate subjected to an underwater blast load. All the problems have been successfully solved, and the proposed phase-field model is proved to be effective.

Numerical investigation on perforated sheet metals under tension loading

Abstract Perforated sheets are used in many areas due to their high specific load, economical production, aesthetic structure, and filtering ability. Their use in industrial machinery and the construction industry can be given as examples of these areas. In this study, the mechanical behaviour of perforated metal sheets under tensile loads has been investigated numerically. The influence of material type, hole geometry, and hole arrangement were examined with finite element analyses. Stainless steel and aluminium materials are used as sheet materials. The hole geometries are circle, ellipse, triangle, square, and hexagon. As a result of the simulations, the aluminium material gave the highest values in terms of carried load capacity and absorbed energy. The sheets with the staggered hole arrangement have higher load and energy values than the sheets with the linear arrangement. The elliptical perforated aluminium sheet provided the highest load value of 28,386 N in the staggered arrangement. In both hole arrangements, the elliptical perforated sheet gave the highest load value, while the triangle perforated sheet gave the lowest load value. The elliptical perforated sheet with linear hole arrangement provided the highest values in terms of specific load (435.57 N/g) and specific energy (0.27 J/g).

Influence of 3D printed downstream support structures on pressure drop and entrainment of oleophilic and oleophobic oil mist filters

Industrially applied coalescence filters, e.g. oil mist filters, usually consist of several filter layers in combination with a downstream support grid. While in the past the focus of research on coalescence filters has been e.g. on the filter media itself, information on the influence of support structures on pressure drop and entrainment is scarce. Recent studies on the influence of support structures on differential pressure and entrainment showed, that stainless-steel perforated sheets are particularly well suited for this purpose. Based on these findings, innovative 3D printed support structures with novel printed modifications, like conical holes instead of cylindrical holes or additional roofs above each hole, in comparison to the state-of-the-art stainless-steel perforated sheets, were developed and evaluated in this work. Especially for oleophilic filter media, where the oil film in quasi-steady state is build up on the filter rear side and thus, noticeably affected by support structures, the differential pressure was in some cases slightly reduced, whereas entrainment was significantly reduced (up to −75%) by the developed 3D printed support structures. For oleophobic filter media entrainment was mainly affected by the 3D printed support structures and was significantly reduced.