Fabrication Of Plates Research Articles

Objective evaluation of integrated structural defects of low-light-level image intensifier based on local image patch extreme and frequency fast Fourier transform

Integrated structural defects are one of the most common defects in the microchannel plate fabrication and physicochemical treatment stage of low-light-level (LLL) image intensifiers. Its appearance seriously affects the imaging quality. The traditional evaluation method of such defects is solely based on visual observation, and its main disadvantages are strong subjectivity and large uncertainty. To address the above problems, two objective evaluation methods of integrated structural defects of an LLL image intensifier are introduced. The first is based on local image patch extreme, and the second is based on frequency fast Fourier transform. The basic idea of the first method is to scan the effective area (EA) of the target image globally and then extract the target defect by adopting a series of local image patch extremes adjacent in the Y-axis. Experimental results reveal that this method shows excellent performance in detecting and positioning accuracy while the time cost is satisfactory. The general steps of the second method are to scan the EA globally, and then perform a fast Fourier transform on the obtained image patch; through bandpass filtering in the frequency domain and inverse Fourier transforming the convoluted image, structures or objects projecting the similar characteristics of integrated structural defects are detected. This method not only maintains good detection integrity but also ensures high detection accuracy. Through experiments on several defective image intensifiers and compared with traditional relevant technologies, we conclude that the proposed methods can realize the high-precision objective detection of integrated structural defects of LLL image intensifiers and can be used as effective alternatives to the traditional evaluation method of such defects.

Mechanical comparison of cold-worked versus cold-worked hot-forged dynamic hip screw system

Purpose: Dynamic hip screw (DHS) plate fabrication has a crucial role in success rate of surgeries for fractures of the proximal femur. Our research focuses on comparing microstructure and mechanical properties of DHS plates fabricated through two distinct processes. We aimed to compare the mechanical cold-worked (CW) DHS plate versus a DHS plate that fabricated through the cold-worked hot-forged (CWH) DHS plate. Methods: The CW and CWH DHS plates had similar topology, however, tested under different loading scenarios. To make the results comparable, the test for the CW DHS plate was simulated and validated utilizing the finite element modeling (FEM) approach. Then, the model (i.e., the CW DHS plate) was analyzed applying the loading scenario of the CWH DHS plate test. Finally, the results of the FEM analysis for CW and the actual test for CWH DHS plates including compression bending stiffness/strength and proof load were compared. Furthermore, the chemical combination of the two plates was analyzed to investigate if they meet the requirements for ASTM F138 standard. Results: Our analysis showed the amount of “Proof Load” and “Compression Bending Strength” of the CWH DHS plate significantly improved by ∼87% in comparison with the CW DHS plate that both fabricated with ASTM F138 material. On comparison between their grain sizes, the CWH DHS plate has a finer grain size (∼55% smaller than CW DHS plate) which leads to larger yield stress. Conclusion: Although the cold-working process according to ASTM F138 leads to enhance the mechanical performance of a DHS plate, adding hot-forging to the process improved the mechanical performance of DHS plate. The outcome of this study could facilitate the development of the optimal fabrication process for surgical implants which in turn will increase the long-term success rate of the relevant surgeries.

Simplified Antibiotic-Coated Plating for Infected Nonunion, Fracture-Related Infection, and Single-Stage Prophylactic Fixation.

Antibiotic-coated implants are increasing in prevalence in the treatment of fracture-related infections. Coated plates may be desirable in certain anatomic locations or to augment nail fixation. We describe a simple, reproducible technique for the fabrication of antibiotic-coated plates and our initial results of a small case series.

Fabrication of Bipolar Plates from Thermoplastic Elastomer Composites for Vanadium Redox Flow Battery.

A vanadium redox flow battery (VRFB) is a promising large-scale energy storage device, due to its safety, durability, and scalability. The utilization of bipolar plates (BPs), made of thermoplastic vulcanizates (TPVs), synthetic graphite, woven-carbon-fiber fabric (WCFF), and a very thin pyrolytic graphite sheet (GS), is investigated in this study. To boost volumetric electrical conductivity, WCFF was introduced into the TPV composite, and the plate was covered with GS to increase surface electrical conductivity. Created composite BPs acquire the desired electrical conductivity, mechanical strength, and deformation characteristics. Those properties were assessed by a series of characterization experiments, and the morphology was examined using an optical microscope, a scanning electron microscope, and atomic force microscopy. Electrochemical testing was used to confirm the possibility of using the suggested BP in a working VRFB. The laminated BP was utilized in a flow cell to electrolytically convert V(IV) to V(V) and V(II), which achieved comparable results to a commercial graphite bipolar plate. Following these experiments, the laminated bipolar plates’ surfaces were examined using X-ray photoelectron spectroscopy, and no evidence of corrosion was found, indicating good durability in the hostile acidic environment.

High efficiency and scalable fabrication of fresnel zone plates using holographic femtosecond pulses

Abstract To meet the growing demand for photonic integration and device miniaturization, planar diffractive Fresnel zone plates (FZPs) are widely applied in integrated optical systems. However, challenges remain in fabricating FZPs with high efficiency and satisfying the requirement for cross-scale fabrication. This paper details a high efficiency method for fabricating ultrathin FZPs of different scales on metal films by using holographic femtosecond lasers. The FZPs are split into a series of element patterns that are printed in order by using corresponding modulated femtosecond pulses. The fabricated FZPs are spliced by the printed element structures with no FZP size limitation in theory. FZPs with an area varying across three orders of magnitude are presented to demonstrate the capability of cross-scale fabrication. The fabricated FZPs possess an excellent broadband focusing and imaging ability in the visible spectrum. Furthermore, the fabrication of other functional ultrathin lenses, such as axial multifocal zone plates, petal-like zone plates, and FZP arrays, is described, revealing the wide potential for the flexible and scalable fabrication method in on-chip integrated optical systems.

Multisector binary phase plates on fused silica for generation of optical vortex beams superposition: Fabrication, characterization, and applications

The paper describes the fabrication of multisector binary phase plates (MBPPs) on fused silica to generate the optical vortex beams (OVBs) superposition. Laser-induced microplasma plays the role of a spot tool for etching sectors which provides the required phase shifts – π and π/2 relative to non-etched sectors. We fabricated MBPPs with four, six, eight, ten and twenty sectors with 0 and π phase levels and plates with eight, ten and twelve sectors with 0 and π/2 phase levels. The depth of etched sectors was controlled by profilometry with vertical resolution ± 10 nm and diffraction-interference contrast optical microscopy. To evaluate the quality and depth of focusing, we analyzed the OVBs superposition with CCD camera. The OVBs superposition exists as spatially separated diffractive limited spots encircling over perimeter of the central area with the intensity reducing to zero. We also measured the efficiency of Gaussian beam conversion into the OVBs superposition for MBPPs of both types. MBPP was used in an optical setup with the nanosecond laser (the wavelength of 1060 nm) for simultaneous processing of steel plates.

Custom Plates in Orthognathic Surgery: A Single Surgeon's Experience and Learning Curve.

Virtual surgical planning (VSP) now allows for the fabrication of custom plates in orthognathic surgery. The senior author was an early adopter, using VSP and stereolithographic splints for over a decade, before transitioning to custom plates in 2019. The authors present our experience and learning curve with this new technology and compare results to a prior cohort of orthognathic patients. A retrospective chart review identified patients undergoing orthognathic surgery with the senior author between 2016 and 2021. All underwent VSP and stereolithographic splint formation, and then either traditional or custom-plate fixation. Demographics, perioperative variables, and postoperative outcomes were analyzed. Traditional fixation consisted of craniomaxillofacial plates, bent intraoperatively by the surgeon to adapt to the facial skeleton. Custom plates were prefabricated and prebent to fit drill holes outlined by customized cutting guides. Forty-three patients underwent surgery in the study period, 25 (58.1%) with traditional fixation hardware and 18 (41.9%) with custom plates. The surgical technique evolved throughout the custom-plate cohort, with the most recent technique involving custom maxillary plate fixation and traditional mandibular plate fixation. When comparing this group of patients to the prior cohort of traditional fixation patients, operative time significantly decreased (mean 233 minutes versus 283 minutes, P = 0.044), without significant difference in complications. Patient-specific cutting guides and custom plates allow for precise spatial positioning of the osteotomized jaw in the orthognathic surgery. Unsurprisingly, obstacles must be overcome in adopting this new technology; here, we outline our experience and technical modifications that have resulted in increased surgical efficiency with comparable outcomes.

Effects of Carbon Fiber Foot Plate on Able-bodied Gait: Pilot Study

ABSTRACT Introduction Foot orthoses have injury prevention and human performance benefits. The carbon fiber foot plate (CFFP) is a possible orthotic intervention for preventing foot injury and enhancing sports performance. However, the cost of these devices is generally acceptable for developed settings but might serve as a barrier for use in developing settings. In this study, we aimed to develop an affordable locally custom-made CFFP and evaluate its function along with subjective feedback. Materials and Methods Three types of foot plates were designed each with a unique layup and fabric orientation. Carbon fiber preimpregnated with activated resin was used for foot plate fabrication. Three participants were provided with each prototype of the foot plate. Outcome measurements include walking speed (20-m walk test [20MWT]), treadmill jogging energy expenditure, and user feedback. Results The 20MWT self-selected speed increased for two participants with the CFFP. The maximum average walking speed increased in two participants with CFFP prototype B (8%–11%). Moreover, the average increase of walking speed for prototypes A and C were 2%–2.6% and 4%–4.6%, respectively. The third participant showed a 5% reduction of speed with CFFP prototype B and 3%–5% with prototypes A and B. For all participants, no improvements of energy expenditure were observed with all prototypes compared to without foot plate. Conversely, an increase in energy expenditure was found with all prototypes at all speeds. The subjective feedback in each prototype showed that all participants were satisfied with the CFFP prototype A, but the first participant was identified with metatarsal head pain. Prototype B also evidenced a consensus among participants with increased comfort compared with prototype A, especially at the metatarsal heads. Conclusions The study describes the development and effects of using three types of CFFPs. Although prototypes increased the energy expenditure, prototype B improved walking speed. Prototypes A and B were useful and accepted by all participants. Further exploration is required in a larger heterogeneous sample of able-bodied persons and sport-specific athletes. Clinical Relevance The study demonstrates the effect of the CFFP on walking ability, which can better inform the clinician when considering the prescription for patients with foot problems and sports activities.

Microstructural characterization of as-fabricated monolithic plates with boron carbide, aluminum boride, and zirconium boride burnable absorbers

• Fabrication of aluminum-based research reactor plates containing boron-based burnable absorbers. • Scanning electron microscopy. • Transmission electron microscopy. • Burnable absorber size and shape distribution analysis. The use of burnable absorbers can be beneficial for nuclear reactors by extending the fuel's operational cycle, providing additional criticality control, and flattening the power profile. In this work, three burnable absorber materials (boron carbide, aluminum boride, and zirconium boride) embedded in aluminum have been fabricated into foils and clad in AA-6061 for potential use in high performance research reactors. The as-fabricated boron-containing phases were determined using transmission electron microscopy to be AlB 2 , B 4 C, and ZrB 2 . TEM also revealed incomplete bonding at the B 4 C-matrix interface. SEM showed a relatively uniform spatial distribution of boron-containing phases for all the candidate materials. Higher porosity was observed in the foil containing ZrB 2 in its as-rolled condition. The porosity in the ZrB 2 foil was reduced by hot isostatic pressing. The size and shape distributions of the boron-containing phases were analyzed on the criteria of cross-sectional area, perimeter, roundness, circularity, and aspect ratio. A method of converting the 2D burnable absorber dispersoids seen in cross-sectional microscopy images into 3D volumes was derived using both spherical and ellipsoidal geometry models. The difference in calculated burnable absorber dispersoid average volume between the two models ranges from 20% to 100%, which could impact burnable absorber burnout rates due to differences in neutron self-shielding.

Fabrication of Stainless Steel Bipolar Plates with Micro Channels by Additive Manufacturing and the Impact of Channel Width on the Fuel Cell Performance

Fabrication of Stainless Steel Bipolar Plates with Micro Channels by Additive Manufacturing and the Impact of Channel Width on the Fuel Cell Performance

Design and Fabrication of Low Cte Aluminum-Silicon Composite Plates by Squeeze Infiltration Technique for Thermal Management Applications

Design and Fabrication of Low Cte Aluminum-Silicon Composite Plates by Squeeze Infiltration Technique for Thermal Management Applications

Study and optimize tensile strength of FSW joints using AA5083 filler by Taguchi & Anova

FSW is a cutting-edge technique that eliminates many of the drawbacks of traditional welding procedures, such as the release of hazardous gases and the need for a large amount of energy to complete the process. Experiments are designed using the Taguchi L9 orthogonal array and ANOVA analysis methods. Analyze the gathered data values to see if tool rotation speed of 850 rpm, 1000 rpm, or 1150 rpm, and tool transverse speed of 25, 35, or 45 (in mm/min) have an effect on the tensile strength of weld joint specimens. FSW fabricates aluminium alloys AA5052, AA5083, and AA6063 in this research utilising AA5083 as filler. Nine specimens with different base metal combinations are created during the experiment, using tool rotation speeds of 850 rpm, 1000 rpm, or 1150 rpm and tool transverse speeds of 25, 35, or 45 (in mm/min). The results show that as the TRS is raised, the tensile strength increases. Taguchi's orthogonal system was used to create the Design of Experiment, which allows for better outcomes with the least number of experiments. FSW has application range in the industrial industry, including shipbuilding, aircraft, and automobile production, and is widely employed in the fabrication of aluminium plates and sheets, as well as steel and magnesium.

Effect of energy on Ti plate fabrication by vacuum selective laser melting for uniformity of grain size

Grain size homogenization by controlling heat input using modulated pulses in additive manufacturing was verified. A Ti plate was fabricated with a modulated pulsed laser by vacuum selective laser melting. 20-layer fabrication was performed with modulated pulsed laser and continuous wave laser. As a result of cross-sectional observation, it was found that the variation of the grain size was smaller when the modulated pulsed laser was used. These experimental results suggest that it is possible to control the grain size by using a modulated pulsed laser.

Fabrication of titanium bipolar plates for proton exchange membrane fuel cells by uniform pressure electromagnetic forming

Electromagnetic forming (EMF) is a type of noncontact and high-speed forming process that offers several advantages, such as high material formability, low springback, and low die cost. In this study, titanium bipolar plates (BPPs) for proton exchange membrane fuel cells are fabricated by EMF using a uniform pressure actuator that provided a uniform pressure distribution and high efficiency. A three-dimensional coupled electromagnetic-mechanical simulation model is established to optimize the dynamic forming process. Simulation results show that the channel depth is proportional to the impact velocity of the titanium workpiece. A forming window is established as a design guideline. Finally, a titanium BPP with sufficient channel depth (0.4 mm), high aspect ratio (0.67), low thinning rate (not exceeding 15.89%) and high corrosion resistance is successfully fabricated at a velocity of 286 m/s, thereby demonstrating that EMF is a feasible process for fabricating titanium BPPs.

Experimental and numerical investigation on fabricating multiple plates by an energy effective explosive welding technique

An innovative explosive welding method for the fabrication of multiple plates (EWMP) was proposed to further improve the energy efficiency of explosive welding explosive charges and reduce the impact on the surrounding environment. In this method, six metal plates were placed in parallel and three composite plates were obtained through one explosion in this paper. The microstructure of the joint was analyzed by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and electron backscattering diffraction (EBSD). Compared to traditional explosive welding (TEW), the EWMP dramatically reduced the noise and vibration and increased the energy efficiency of explosives. The results showed the vibration data of EWMP were reduced by 16.7, 16.4, 2.8, and 1.5%, respectively, and at places of 3, 4, 5, and 6 m away from the explosion center, and explosive consumption of EWMP was reduced by at least half, compared to the traditional method when obtaining the same amount of welded plates. Through numerical simulation, the collision speeds of the composite plate are 610, 516, and 471 m/s, respectively, and the waveform of the composite plate is basically in coincidence with the result of the experiment.

The Time for Industrialization Has Come: A Pre-Coated Solution for the GW Scale

Green Hydrogen has become present in all mass media thanks to their ubiquitous role to overcome the issues related to climate change. It is estimated that green hydrogen and their associated technologies (i.e. fuel cells and electrolysers) will represent 25 % of the total energy mix by 2050 if a 100 % renewable system is achieved. Among these technologies are Solid Oxide Cells (SOC). This technology has the capability to be the more efficient technologies among fuel cell and electrolyser’s technologies as well as the technology made from cheaper and more abundant materials. In addition to this, it has also the capability to function much more easily in reversible mode that their fuel cell and electrolyser siblings (AEM, PEM or even AEM) which give them a great versatile capacity.In order to make Green Hydrogen a reality and to succeed, an immense work in terms of industrialization needs to be done. In the following years, the industry needs to prove that is ready to deliver the systems in the large volumes that it is going to be demanded if we want to give response to our climate goals (i.e. GW per year). For instance, by 2030 it is estimated that 500 000 micro-CHP (combined heat and power) units will be installed only in the European Union which would require the production of at least as many fuel cell systems for such application. This large number, make a very rapid fuel cell industrialization necessary and a suitable value chain must thus be created.Sandvik Materials Technology (SMT) is a material provider for the more demanding industries and applications. During our more than 160 years of history, the company has delivered large volumes of materials in forms of tubes and strips, for instance. Solid Oxide Cell systems are constituted by many tubes and strips made of special stainless steel alloys in which SMT is specialized of. More recently, SMT has developed a coil-to-coil process to produce pre-coated strip for the fabrication of bipolar plates and interconnects in both PEM fuel cells and electrolysers but as well for SOC. The pre-coated concept allows the industry to have a cost-effective process ready for the rapid ramp-up of both fuel cell and electrolysis technologies.Regarding SOC, Sanergy HT 441 is designed to be used as interconnect material. The product is made at industrial scale by Physical Vapor Deposition in the above-mentioned roll-to-roll coating method. It is based on an ASTM 441 steel grade double coated with thin layers of Ce and Co (< 1 µm). The material can be double side coated with the same coating or with a different coating in the other side. This material has shown to form a protective (Co,Mn)3O4 spinel layer that improves corrosion resistance and heavily reduces Cr evaporation. Recent studies has shown that Cr evaporation is reduces up to 10 times thanks to the Ce and Co coating. On the other hand, very recently it has been put on the table challenges with use of Co due to both societal and economical conflicts. At Surface Research in SMT, different Co-free coated materials has been developed in order to offer a different solution to this. Therefore, this work will show the solutions that SMT put in the market to industrialize fuel cells and electrolysis, and concretely SOCs.

Modeling, design, materials and fabrication of bipolar plates for proton exchange membrane fuel cell: A review

Bipolar plate is one of the most significant components of the proton exchange membrane fuel cell, which serves as the function of reactant gases supply, reaction products removal, current collection, structural support and so on. How to obtain superior bipolar plate, including uniform gas distribution, good water management, lower pressure drop, higher power density, lower cost, high mechanical strength, and easy fabricating, has become a technical challenge and future trend. This article aims to provide a comprehensive review of major findings of researches on modeling, flow field design, materials, and fabricating process of bipolar plate in recent year. The results demonstrate that the three-dimensional, steady-state, multi-phase, computational fluid dynamics model have become the most popular simulation method to assess the flow field design of bipolar plate. Also, the influencing factors, such as channel-land (rib) dimensions, baffles and flow channel shape, are considered as the significant elements that guide the flow field design and affect the performance of proton exchange membrane fuel cell. In addition, due to lower interfacial contact resistance, better corrosion resistance and lower cost, the coated stainless steel bipolar plates have shown greater advantages and potentialities in comparison to other bipolar plates. Four common fabricating methods are proposed to solve the metal plate processing problem. Finally, this review is expected to provide the guidance for the future development of bipolar plates.

Numerical simulation of outgassing characteristics of microchannel plate glass

Outgassing of internal materials is one of the main factors that cause vacuum deterioration of low-light-level image intensifiers and shorten their lifetime (especially storage lifetime). To perceive the attenuation mechanism of the vacuum degree of image intensifiers from the microscopic view, the outgassing characteristics of lead silicate glass used for the fabrication of microchannel plates (MCPs), which are the core components of image intensifiers, were numerically simulated by giant canonical Monte Carlo and molecular dynamics methods. A glass structure model of the third-generation MCPs was constructed, and the diffusion coefficients and molecular motion trajectories of hydrogen, carbon dioxide, carbon monoxide, water vapor, oxygen, and methane gases, together with their outgassing rates and cumulative outgassing amounts, were calculated based on the condensed-phase optimized molecular potentials for atomistic simulation studies force field. The calculation results show that the rising temperature of MCP glass augments the diffusion coefficients of these gases, which makes the outgassing rates increase in the initial stage but then decrease relatively quickly. Among these six kinds of gas molecules, hydrogen molecules have the largest skip distance and the highest diffusion coefficient because MCP glass can supply more effective diffusion paths for the gas molecules with a relatively small size. When an MCP glass lies in vacuum, first, the cumulative outgassing amounts of various gases from it increase rapidly and then gradually reach stable values, and the cumulative outgassing amount of hydrogen tends to reach a stable value faster than that of other gases due to its highest diffusion coefficient.

Enhanced biomechanical performance of additively manufactured Ti-6Al-4V bone plates

As the global trauma fixation devices market expands rapidly, it is imperative to improve the production of fixation devices through enhanced design accuracy and fit for best performance and maximum patient comfort. Selective laser melting (SLM) is one of the mature additive manufacturing methods, which provides a viable route for the rapid production of such devices. In this work, the ability of SLM to produce near-net-shape parts, as desired for medical implants, was utilized for the fabrication of bone plates from Ti-6Al-4V alloy powder. Martensitic microstructure obtained after the printing of alloy resulted in poor ductility, limiting its application in the field of orthopedics. A specially designed repeated cyclic heating and cooling close to but below the β-transus was used to transform from acicular to a bimodal microstructure without the need for plastic deformation prior to heat treatment for improving the ductility. Bone plates subjected to this heat treatment were mechanically tested by means of tensile and 3-point bend tests and demonstrated large improvement in ductility, and the values were comparable to those similar plates prepared from wrought alloy. Other important properties required for implants were assessed, such as corrosion resistance in simulated body fluid and cytocompatibility in vitro using MC3T3-E1 cells. These results for the bone plate after heat treatment were excellent and similar to those of the additively manufactured and wrought plates. Taken together, the performance of the additively manufactured bone plates after subjecting to heat treatment was similar to those of bone plate manufactured using wrought alloy. These results have important implications for the fabrication of patient-specific metallic orthopedic devices using SLM without compromising their biomechanical performance by subjecting them to a tailored heat treatment.

Perforated Plate for Ballistic Protection—A Review

In recent years, the interest of the scientific community in perforated plates for ballistic protection has increased. Perforated plates do not represent protection by themselves, rather, they are used in the armour systems of armoured vehicles, in conjunction with base armour, since they are intended to induce bend stresses, where a penetrating core fracture occurs. The fragments are subsequently stopped by base armoured vehicle armour. Although for the first time used several decades ago, perforated plates are found to be attractive even today. The main reason is the combination of very convenient properties. Besides high mass effectiveness, they possess a high multi-impact resistance, since their perforations arrest cracks. Therefore, a relatively wide array of materials is suitable for perforated plate fabrication, ranging from alloy steel to some types of cast iron. Being made of metallic materials, raw material costs are relatively low compared to ceramics or composite materials, making them very attractive for present and future armoured vehicles. Finally, armour system consisting of a perforated plate and base plate at some distance, reduce the effectiveness of both shaped charge jets and act as blast mitigators.