Original Plate Research Articles

Numerical Modeling of a Hot Plate Stove for Peanut Roasting

Heat treatment, especially roasting, is known to reduce harmful fungal species and mycotoxin formation to a great extent. Experiments were conducted for heat treatment and the effects of introducing different fin configurations. ANSYS Fluent 14.5 was used to simulate the three-dimensional (3D) roaster geometry. The effect of the addition of different fins at the bottom of the hot plate was then studied. It was observed that maximum surface temperatures of 133°C, 153.25°C, 310.63°C, and 265.07°C were obtained after 180 minutes (three hours) for the experimental (without fins), predicted (without fins), predicted (with rod fins), and predicted (with honeycomb fins), respectively. The addition of honeycomb and rod fins to the roster’s plate increased temperatures by 115.34% and 143.03% of the original roaster hot plate. Thus, a design with rod fins added to the hot plate could improve its thermal performance and hence reduce the harmful effects of possible fungal species and mycotoxin contamination.

The Microstructure and Property of a Titanium-Carbon Steel Clad Plate Prepared Using Explosive Welding

The microstructure and properties of pure titanium (Ti)-carbon steel clad plate prepared using explosive welding were characterized. The bonding of the welding interface was inspected using C-scanning imaging technique. The microstructure and composition of the clad were characterized with optical microscopy and scanning electron microscopy. Mechanical and corrosion properties of the clad plate were investigated using tensile test, shearing test, and potentiodynamic polarization measurement. The results show that the pure titanium and carbon steel plate are joined successfully without visible defects. The interface wave is uniform. SEM observation and EDS analyses show that some melt blocks distribute at the interface waves vortices. Hardness testes results show that after heat treating, the hardness values in the titanium layer of the clad plate are similar to the original titanium plate, whereas the values at carbon steel layer increase from the interface to 300 μm away. Tensile and shearing test results indicate that the mechanical properties of the clad meet the requirements of ASTM B898 standard. Corrosion test shows that the Ecorr of the clad plate is more positive, and icorr is 1 order of magnitude lower compared to carbon steel material, suggesting that the corrosion resistance of clad plate is better than that of carbon steel material. These results suggest that the clad plate has good bonding quality and properties to meet the processing requirement and can be safely applicable in the petrochemical field.

Musical Motifs in Graphic Decorations of Nicolas Vallet’s Lute Tablatures (1615–1616)

The National Museum – Czech Museum of Music holds an important source – a bundled collection of three printed sets of lute tablature by Nicolas Vallet, which contains parts I and II of Le Secret des Muses (1615, 1616) and the psalm collection Vingt et un pseaumes de David (1615). In our examination of graphic motifs, we focused on musical motifs worked into the decorating of initials and especially on depictions of the Biblical figure of King David with a lute, of lutenists, and of the lutes themselves. The schematic depictions of the instrument did not provide any new organological discoveries, but instead confirmed the popularity of the lute as a symbol. Vallet’s tablatures were printed from original full-page copper engraving plates and not from individual blocks, as was customary. It is also for this reason that the initials, decorated with genre pictures and Biblical scenes, have merited extraordinary attention.

Aerodynamic Performance of a Nanostructure-Induced Multistable Shell

Multistable shells that have the ability to hold more than one stable configuration are promising for adaptive structures, especially for airfoil. In contrast to existing studies on bistable shells, which are well demonstrated by the Venus flytrap plant with the ability to feed itself, this work experimentally studies the aerodynamic response of various stable configurations of a nanostructure-induced multistable shell. This multistable shell is manufactured by using nanotechnology and surface mechanical attrition treatment (SMAT) to locally process nine circular zones in an original flat plate. The aerodynamic responses of eight stable configurations of the developed multistable shell, including four twisted configurations and four untwisted configurations with different cambers, are visually captured and quantitively measured in a wind tunnel. The results clearly demonstrate the feasibility of utilizing different controllable configurations to adjust the aerodynamic performance of the multistable shell.

A novel brush surface structure of SiCf/SiC composites designed for brazing improvement

The brush surface structure of SiCf/SiC has been designed to obtain the robust SiCf/SiC-alloy joint by reducing the residual stress and improving interface bonding. SiC fibers are exposed through thermal corrosion at a low temperature, forming the transition layer of SiC fiber-reinforced AgCuTi. The transition layer replaces the original plate reaction layer, which increases the joining area effectively and forms the 3D network of the reaction layer. The crack propagation is hindered, and SiC fibers increase the interfacial bonding. The residual stress is reduced by decreasing the property mismatch between SiCf/SiC and alloy with this transition layer. All these improvements contribute to the high shear strength. The shear strength of joints reached 41.4 MPa with the transition layer of 67 μm, twice higher than that of original joints of 20.7 MPa.

Conductive materials for connecting tires of multi-element accumulator traction batteries

The article deals with the choice of materials for connecting tires of traction batteries (TB). The optimal parameters of their spot welding with batteries are experimentally established (the first pulse with a current of 7 kA duration of 1 ms, the break between the pulses of 1 ms, the second pulse with a current of 7 kA duration of 2 ms). When operating the traction battery on electric vehicles, the resistance of the connecting tires should not lead to heating of the batteries in order to avoid overheating above 60 °C. In most modern TB, consisting of Li-ion elements, a nickel tape is used for the connection. To ensure the weldability of materials (copper–nickel or nickel–nickel), it is important that the operating temperature is reached at a short-term current pulse in the welding zone. One of the solutions to this problem is the application of a metal coating. Experiments were conducted on the weldability of various materials, including those with applied coatings. The best results in weldability were shown by tires made of tinned copper, which was welded to nickel plates (emitting the battery body). Tear tests of the welded samples were carried out. The tensile strength of the original copper tires was 340–450 MPa. When welding copper–nickel and copper(tinned) – nickel plates, the strength limit values reach 70 % of the strength of the original copper plate. On the basis of the obtained experimental data, a pilot batch of battery TB was manufactured, which successfully passed tests for compliance with the technical requirements for the strength and the value of the transition resistances of the welded joints of connecting buses with batteries.

Numerical and Experimental Study on Suppression Effect of Acoustic Black Hole on Vibration Transmission of Refrigerator Compressor

The acoustic black hole (ABH) structures have the potential to achieve structural vibration suppression and noise reduction through the effect of the ABH on the concentration and manipulation of flexural waves. In this paper, a new solution is proposed to embed 2-D ABHs on the support plate to suppress the transmission of compressor vibration to the refrigerator body. The vibration and acoustic measurement experiment of the compressor, the support plate and the refrigerator body, and the coherence analysis of the vibration signals and acoustic signal are carried out to determine the influence of the compressor vibration on the vibration of the refrigerator body and the radiation sound of the back wall. The concentration and manipulation effects of 2-D ABH on flexural waves are verified by numerical simulation of flexural wave propagation in the time domain. FEM models of the original support plate and the damping ABH support plate are established to investigate the comprehensive effect of the 2-D ABHs and the damping layers on the vibration characteristics of the support plate through vibration modal and dynamic response analysis. Numerical simulation results show that the 2-D damping ABHs can suppress the vibrations generated by the compressor at specific frequencies in the middle and high-frequency bands from being transmitted to the refrigerator body through the support plate.

Improvement of Mechanical Properties and Forming Efficiency during Hot Gas Forming of CFRP Curved Surface Components.

Carbon fiber reinforced plastics (CFRP) are widely used in aerospace and new energy vehicles due to their high specific strength and flexible design ability. At present, the traditional forming process of CFRP curved surface components has problems of low mechanical properties and long processing time. In this paper, a new method of hot gas forming was proposed to obtain CFRP components. By applying high temperature and high-pressure gas on one side of CFRP, the material was forced to deform and solidify at the same time. A special device for hot gas forming was designed and developed. The curing behavior and mechanical properties of original CFRP plates were studied. The main defects and the corresponding control methods of hot gas forming parts were analyzed by forming spherical parts, and the feasibility of the hot gas forming process was verified. Taking the battery cover plate of a new energy vehicle as the research object, the influence of forming temperature, gas pressure, pressurization rate and other process parameters on the mechanical properties of complex CFRP components were analyzed. The mechanism of both strength and efficiency improvement was analyzed. The results showed that with the increasing of gas pressure, the tensile strength and forming efficiency of the CFRP curved components were improved obviously. Under reasonable forming parameters, the tensile strength of the obtained parts was increased by 37%, and the forming efficiency was increased by 58%. The fiber bundles were distributed more evenly and compactly under the hot gas forming. This showed that the use of hot gas forming had good potential in the preparation of high-performance CFRP parts, which was helpful to improve the processing efficiency and forming quality of CFRP curved parts in the aerospace and new energy automotive fields.

Static, buckling and free vibration analyses of composite sandwich plate with bi-directional trapezoidal cores using VAM-based reduced plate model

The geometry of the composite sandwich plate with bi-directional trapezoidal cores (BTCs) is characterized by its novel cores with trapezoidal convex and concave corrugations in two in-plane directions. To solve the related difficulties in mechanical problems, a reduced plate model is established and written as a variational formulation based on the variational asymptotic method (VAM). That is, the original 3D plate problem was reduced to unit cell analysis (providing effective plate properties, such as the A, B, and D matrices) and two-dimensional (2D) reference plane analysis. To validate the accuracy and effectiveness of the reduced plate model, we analyze the static displacement, global buckling, and free vibrations of the composite sandwich plate with BTCs under different boundary and load conditions. Finally, we investigate the influence of the layup configurations of the face sheet and geometric parameters of the BTCs on the effective plate properties, buckling loads, and natural frequencies of the plate, which can provide useful reference for the structure optimization of composite sandwich plate with BTCs.

3D‐Printing with steel of a bolted connection

AbstractAdditive Manufacturing seems promising for the steel construction industry, especially for small components with complex shapes. With Wire‐and‐Arc‐Additive‐Manufacturing (WAAM) a process was found which is fast and cheap compared to other Additive Manufacturing processes for metals. Furthermore, arc‐welding is well known in steel construction industry.Bolted head plates are a common connection. Although they are relatively easy to produce, they are uneconomical in load transfer due to straining of the plates which are subject to bending. This type of connection is predestined for Additive Manufacturing. Rethinking the structure by taking into account the potentials of Additive Manufacturing brings a clear advantage compared to the conventional production. Thus, with a material saving of 60 % the same load capacity of the original flat head plate can be achieved.The paper shows how the new production process WAAM can significantly change the shape of structures on the example of a bolted head plate. Therefore, all steps from the original design to the manufactured structure are demonstrated, including the structure finding by using topology optimization, the manufacturing with different parameters and a first testing of the manufactured structures.

Experimental study of the strength characteristics of fixation of the symphysis pubis with an original plate for the reconstruction of the anterior pelvic semi-ring

The destabilization of bone fixators has led to repeated surgical interventions that increased the risk of migrations of metal fixators, infectious and inflammatory complications as well. The modern trends in hip bone injury surgery are related to developing and using of metal fixators, which are effective in acute injury; however, sometimes the condition of the patient and the technical support of hospitals don’t allow performing surgery in the acute period, and these metal fixators are ineffective for chronic damage. Consequently, until now, the problem of finding the optimal design of structures for fixing chronic damage of anterior pelvic semi-ring which will be able to exclude its destabilization, is still of current interest.The purpose of the study: developing and experimental researching of durable features of original plate for reconstruction of the anterior pelvic semi-ring.Materials and methods: In order to ensure stable fixation of chronic pelvic injuries, the original metal plates have been worked out. They are made individually in accordance with the anatomical and functional structures of the anterior pelvic semi-ring of the patient with using additive technologies. The study of the reliability of the different variants of ostiosynthesis of the anterior pelvic semi-ring with using well-known pelvic plates and a new original design was carried out. Stability tests for different plate fixing methods and mechanical strength of metallophyxators were carried out on a universal test machine of LFM-50kN series.Results: one plate fixation in tensile test showed the lowest result – 0.341 kN, a low result of shear loads was received with the same object. The best result was shown by the polyaxial monolithic plate fixation in case of stretching – 0.51 kN at the shear loads – 0.591 kN. Necessary force applied to destabilizing of the metal structure while using a polyaxial monolithic plate was a half-higher than stretched, and a third higher than at shear loads, it demonstrates the benefits of using these metal fixators.Conclusion: It is experimentally confirmed that the polyaxial monolithic plate provides the highest stability of fixing anterior pelvic semi-ring indicator in contrast with fixing of one or two plates.

Substitution approach for decoupled two-scale analysis of materially nonlinear composite plates

A new substitution approach is proposed for decoupled two-scale analysis of a materially nonlinear composite plate with in-plane periodic meso-structures within the framework of computational homogenization. The macroscopic nonlinear mechanical behavior of the plate is characterized by numerical plate tests on an in-plane unit structure (IPUS), which enables us to obtain the relationship between macroscopic resultant stresses and generalized strains. Then, we postulate that the original composite plate can be substituted by an equivalent laminated plate that exhibits approximately the same macroscopic response. The material parameters of each lamina of this substitute, which is referred to as mesoscopic substitution model (meso-SM), are identified using an optimization method so that it could be equivalent to the original IPUS. After the parameter identification, the corresponding macroscopic substitution model (macro-SM) can be analyzed with appropriate analysis software that supports laminated plate elements. Representative numerical examples are presented to validate the appropriateness of the proposed approach by performing comparative calculations with the results obtained from the original composite plates.

ANALYSIS OF CORROSION DEPTH PERCENTAGE ON THE INNER BOTTOM PLATES OF AGING BULK CARRIERS WITH AN AIM TO OPTIMIZE CORROSION MARGIN

To ensure the better structural integrity and maximum safety of bulk carriers in the ship design phase, an appropriate corrosion margin is introduced by the classification societies, which should enable the exploitation of ships during the projected 25-year life cycle. The new Common Structural Rules introduce even higher corrosion margin value to ensure the structural integrity of the ship. This directly affects the increase in hull weight and thus the need for more total installed power and higher fuel consumption. Higher fuel consumption results in increased emissions which directly affects environmental pollution. For these reasons, efforts are being made to introduce alternative energy sources, cleaner fuel, ship weight reduction, and the overall economic efficiency of ships. Therefore, using experimental data collected on aging bulk carriers, the paper explores the corrosion margin reduction potential considering its impact on hull weight. Assuming that the corrosive processes occur after four years of operation, a linear model that describes the percentage of plate wear as a function of the as build-in the thickness of inner bottom plates (IBP) of fuel oil tanks (FOT) located on the double bottom of aging bulk carriers, is analyzed. Over the course of 25 years, the IBP segment was monitored on 36 different ships surveys. In this way, 520 input data describing the depth of corrosion were formed. At the same time, records were kept on the mean thickness of the original metal plate, which enabled systematization of the empirical database and grouping of measured values by intervals of original plate thicknesses, and simple conversion of corrosion depth into adequate percentage values. Depth corrosion percentages were represented by standard linear models known in the literature. Based on this analysis, representative numerical and graphical results were obtained. Conclusions from the paper can assist to optimize corrosion margin and the energy efficiency of future vessels.

ANALYSIS OF CORROSION DEPTH PERCENTAGE ON THE INNER BOTTOM PLATES OF AGING BULK CARRIERS WITH AN AIM TO OPTIMIZE CORROSION MARGIN

To ensure the better structural integrity and maximum safety of bulk carriers in the ship design phase, an appropriate corrosion margin is introduced by the classification societies, which should enable the exploitation of ships during the projected 25-year life cycle. The new Common Structural Rules introduce even higher corrosion margin value to ensure the structural integrity of the ship. This directly affects the increase in hull weight and thus the need for more total installed power and higher fuel consumption. Higher fuel consumption results in increased emissions which directly affects environmental pollution. For these reasons, efforts are being made to introduce alternative energy sources, cleaner fuel, ship weight reduction, and the overall economic efficiency of ships. Therefore, using experimental data collected on aging bulk carriers, the paper explores the corrosion margin reduction potential considering its impact on hull weight. Assuming that the corrosive processes occur after four years of operation, a linear model that describes the percentage of plate wear as a function of the as build-in the thickness of inner bottom plates (IBP) of fuel oil tanks (FOT) located on the double bottom of aging bulk carriers, is analyzed. Over the course of 25 years, the IBP segment was monitored on 36 different ships surveys. In this way, 520 input data describing the depth of corrosion were formed. At the same time, records were kept on the mean thickness of the original metal plate, which enabled systematization of the empirical database and grouping of measured values by intervals of original plate thicknesses, and simple conversion of corrosion depth into adequate percentage values. Depth corrosion percentages were represented by standard linear models known in the literature. Based on this analysis, representative numerical and graphical results were obtained. Conclusions from the paper can assist to optimize corrosion margin and the energy efficiency of future vessels.

Enhancing bandwidth of metamaterial plate with linear and nonlinear passive absorbers

In this work, passive vibration absorbers are used to obtain a metamaterial vibrating plate. For this purpose, a set of linear and nonlinear passive absorbers are used. The plate is modeled based on Mindlin’s theory in which the effects of rotary inertia and shear deformation are considered. The metamaterial plate is considered to be both linear and nonlinear, with a set of linear, nonlinear, and viscous absorbers (Maxwell and Maxwell–Voigt). By optimizing the absorber parameters, a noticeable reduction in the vibration amplitude of the plate is obtained, without imparting a significant mass to the original plate. The effects of mass, stiffness, damping of the absorber as well as the number of absorbers are also investigated so that the sensitivity of the behavior of the system with changing the parameters is minimized. The effect of absorbers at lower frequencies is the main focus of this work. There is more than 77% reduction in the vibration amplitude of the plate, while the total added mass is lower than 10%, which is much less than the values given in similar works. Also, the nonlinear effects of the plate have been greatly reduced and no new resonances with sufficient bandwidth have emerged, and linearization of the nonlinear plate with absorber is achieved. Finally, the performances of the used absorbers are compared.

Investigation of the Long-term Variation of Solar Ca ii K Intensity. I. Density-to-intensity Calibration Formula for Historical Photographic Plates

Abstract This paper presents a novel formula to convert photographic density into intensity for historical photographic plates of the Sun. Photographic photometry is of great importance as the very first step of analyzing century-long archived photographic data to study the long-term variation. The calibration formula is newly developed by using the intensity fluctuation originating in the network pattern in the quiet region, taking into consideration the nonlinearity between the density and the intensity. The formula is useful especially when experimentally obtained characteristic curves are insufficient for homogeneous analysis of a whole long-term data set. An example procedure of the calibration using the formula is demonstrated. Resultant intensity images calibrated from the photographic data can reproduce both the fluctuation and the center-to-limb variation of modern reference data. The calibration procedure is also tested with a whole twentieth century data set and shows good performance, while the preliminary result of the long-term intensity variation seems to be partially affected by the quality of the original plates. The resultant solar Ca II K intensity variation will be updated and discussed in a subsequent paper with the comparison to the solar UV variation related to the terrestrial environment.

Typification and synonymy of the Atlantic Forest endemic species Napeanthus primulifolius (Gesneriaceae)

During the nomenclatural revision of Acanthaceae names described by Friar J.M.C. Vellozo in his Florae fluminensis, we realized that Pedicularis acaulis Vell. was conspecific with Napeanthus primulifolius (Gesneriaceae), a Brazilian Atlantic Forest endemic species. This study presents the complete and updated synonymy of N. primulifolius, including two new synonyms: Pedicularis acaulis and Oreocharis notha C.B.Clarke. We also propose a lectotype for N. primulifolius based on G.Raddi’s specimens and P. acaulis based on Vellozo’s original plate.

Typification of Opuntia australis (Cactaceae) with an original plate from 1882 and history of the plant’s finding

The neotypification of Opuntia australis F.A.C.Weber, basionym of Pterocactus australis (F.A.C.Weber) Backeb., is made here thanks to the discovery of Weber's personal notes about it, and of two notebooks containing respectively a drawing and a short description of that plant, both made at the time of its first collection in 1882. Outlined as well is the poorly documented scientific expedition that made this first discovery and the cultivation of an early plant by F.E. Schlumberger on Weber’s behalf. A Weber’s note confirms he knew the mentioned illustration. A herbarium specimen from the same gathering has been found, but it cannot be considered original material since there is no evidence that it was seen by Weber. However, this specimen is here designated as Epitype.

The Effect of Top Surface Lubrication on the Friction Stir Welding of Polycarbonate Sheets

Abstract In this work, top surface lubrication during friction stir welding of polycarbonate sheets was applied. A homogenous layer of Paraffin wax has been placed on the top surface of the joint area with a width that ensures to cover the shoulder diameter. Then FSW was applied using conventional FSW tool with rotating pin and shoulder at different FSW parameters (Rotation speeds of 1 000, 1500, 2 000 min–1 and welding speeds of 25, 50, 75,100 mm/min). The main objective of using the wax is to act as a lubricant that reduces the friction between the shoulder and the polycarbonate surface. The joints produced were investigated in terms of surface quality, internal defects, and mechanical properties. During FSW the wax is melted and played as lubricant between the tool shoulder and the polycarbonate surface and resulted in defect-free surface with no thickness reduction of the original plate. The transverse cross-section showed defect-free joints for the majority of the FSW parameters investigated. Tensile testing results showed a reduction of the tensile strength after FSW, and an enhancement in the tensile strength with the increase of welding speed or rotation speed. The fracture occurs at the joint zone and the fracture surface investigation using SEM showed the existence of spherulitic structure in the weld joint.

A simple finite element procedure for free vibration of rectangular thin and thick plates

A simple finite element procedure is introduced and developed to solve the free vibration problem of rectangular plates. The proposed method first reduces the original plate problem to two simple beam problems. Each beam problem is then discretized separately with the help of one-dimensional finite element method (FEM). Since only the one-dimensional FEMs are dealt with in the proposed approach, the implementation of the proposed approach is much easier than the case where the two-dimensional FEM is applied to the problem. The reliability and applicability of the proposed method are demonstrated herein through the solution of some illustrative problems, including the vibration problems of thin and thick rectangular plates. The simulations have been done for plates with different boundary conditions including the simply supported, clamped, and free boundary conditions. The results generated by the proposed method are compared with analytical and numerical results available in the literature and excellent agreement is achieved.