Pressing Process Research Articles

Studying Performance and Kinetic Differences between Various Anode Electrodes in Proton Exchange Membrane Water Electrolysis Cell.

The electrode, as one of the most critical components in a proton exchange membrane water electrolysis (PEMWE) cell for hydrogen production, has a significant impact on cell performance. Electrodes that are fabricated via various techniques may exhibit different morphologies or properties, which might change the kinetics and resistances of the PEMWE. In this study, we have successfully fabricated several electrodes by different techniques, and the effects of electrode coating methods (ultrasonic spray, blade coating, and rod coating), hot press, and decal transfer processes are comprehensively investigated. The performance differences between various electrodes are due to kinetic or high frequency resistance changes, while the influences are not significant, with the biggest deviation of about 26 mV at 2.0 A cm−2. In addition, the effects of catalyst ink compositions, including ionomer to catalyst ratio (0.1 to 0.3), water to alcohol ratio (1:1 to 3:1), and catalyst weight percentage (10% to 30%), are also studied, and the electrodes’ performance variations are less than 10 mV at 2.0 A cm−2. The results show that the PEMWE electrode has superior compatibility and redundancy, which demonstrates the high flexibility of the electrode and its applicability for large-scale manufacturing.

Effects of Severe Plastic Deformation and Ultrasonic Treatment on the Structure, Strength, and Corrosion Resistance of Mg-Al-Zn Alloy.

Nowadays, there is a great demand for increasing the strength and corrosion resistance of magnesium alloys for their wider use in machine engineering, oil industry, and medicine. This paper is devoted to a study on the effects of the combined process of reduction and equal channel angular pressing, as well as the subsequent ultrasonic irradiation on the structure, strength, and corrosion properties of the Mg-Al-Zn alloy. Deformation processing results in an increase of the strength up to 280 ± 10 MPa. A fine-grained structure is formed with a grain size of 10–20 µm and small recrystallized grains 1–2 µm in size. The corrosion resistance in the HCl medium falls down significantly. Action of ultrasound on the deformed specimen leads to an increased fraction of high-angle boundaries, in particular, the fractions of special, fully overlapping Σ13a boundaries and twin boundaries of Σ15b and Σ17a systems. Due to the ultrasonic treatment, the strength of the Mg-Al-Zn alloy increases up to 310 ± 5 MPa, while the corrosion resistance in HCl almost doubles.

Determination of Content and Oil Losses in Meal through Palm Kernel Pressing Process at PT XYZ Belawan

<p class="E-JOURNALAbstractBodyEnglish">PT XYZ Belawan has a kernel crushing plant unit that produces Crude Palm Kernel Oil (CPKO) with 700 tons/day capacity. Palm kernel processing is carried out in two pressing stages. The first stage or first press produces oil and cake, while the second stage or second press produces oil and meal. The meal still contains 7-8% of the oil content. This study is aimed to determine the amount of CPKO yield, oil content, and oil losses in a meal during the pressing palm kernel process. The method used was the calculation of the mass balance in each process flow. The mass balance calculation is carried out after collecting the secondary data from the factory, including the analysis of water content, solids, FFA, and oil content. Based on the calculation results, CPKO yield was 48.10% of the average kernel mass rate of 714.7155 tons and met the plant standard of at least 44%. Furthermore, the average yield of oil content from the meal was 7.45% and oil losses were 3.86%.</p>

Effect of Holding Time and Temperature of Hot Pressing on Tensile Strength of Biodegradable Plastic Made of Carrageenan

The most significant environmental problem was caused by plastic. One way to handle plastic waste was using biodegradable plastic because it faster decomposes naturally. Biodegradable plastic can be made from carrageenan by the hot press method. This method can make biodegradable plastic with large dimensions. However, the plastic quality depended on the holding time, temperature, and pressure selected during the hot pressing process. Therefore, this research is conducted to determine the effect of holding time and temperature in the hot press process on the tensile strength of biodegradable plastic made from carrageenan. The composition of the biodegradable plastic material used was 35% carrageenan, 35% polyvinyl alcohol (PVA), and 30% glycerol. In the manufacture of composites, the holding time was varied: 10, 20, 30, and 40 minutes, as well as the process temperature varied from 100, 110, 120, and 130 °C. The tensile strength of the composite was observed through tensile testing using a Universal Testing Machine. FTIR, XRD, and SEM tests were also conducted to sharpen the analysis. The addition of holding time led to an increase in the tensile strength of biodegradable plastics. The highest tensile strength was obtained at a holding time of 30 minutes with a value of 4.45 MPa. After 30 minutes, the tensile strength of the biodegradable composite decreased. Meanwhile, the addition of process temperature caused a decrease in the tensile strength of biodegradable plastics. The highest tensile strength was obtained at a process temperature of 100 °C with a value of 5.28 MPa.

공익신고와 취재원보호의 법적문제

The protection of reporters is a means to protect the freedom of the press, and the free circulation of information cannot be expected without the protection of the reporters. In addition, if the professional duty and conscience of a journalist are presupposed, the protection of reporters should be guaranteed. Theoretically, the protection of reporters guarantees free press coverage and, along with the protection of public interest whistle blowers, will serve as the basis for the development of democracy by monitoring authorities in power and satisfying the people's right to know. In this regard, the Code of Conduct for Journalism Ethics stipulates that the identity of a reporter should not be revealed if the safety of the reporter is in danger or there is a risk of being unfairly disadvantaged. In particular, crime-related reports require very thorough security for the identity of the informant as there is a possibility of secondary damage to the informant due to the disclosure of the identity of the informant. In addition, the protection of public interest whistle blowers is protected by the relevant laws, and there are penalties for violations. There are also views claiming that the scope of protection of sources is not limited to professional and professional media organizations and journalists, but rather broad protection in the free press process. Of course, this will have to be considered more carefully. It would be most effective to take legal action for the protection of sources. This is because it can guarantee their predictability between potential informants and media agencies. However, due to the nature of the Korean media, which shows problems such as abuse of anonymous reporting, sensationalism, and partisanship, it is also true that the law to protect reporters is sometimes criticized for their right to enjoy privileges. Even if there is no law on reporters, judicial administration should make efforts to protect reporters through the freedom of speech guaranteed by the Constitution.

Solvent-Free Fabrication of Thick Electrodes in Thermoplastic Binders for High Energy Density Lithium-Ion Batteries.

The rapid development of electric vehicles has generated a recent demand for high energy density lithium-ion batteries (LIBs). One simple, effective way to enhance energy density of LIBs is to increase the thickness of electrodes. However, the conventional wet process used to fabricate thick electrodes involves the evaporation of large amounts of organic solvents, which causes an inhomogeneous distribution of conductive additives and binders. This weakens the mechanical and electrochemical network between active materials, resulting in poor electrochemical performance and structural degradation. Herein, we introduce a new strategy to produce homogeneous thick electrodes by using a dry, solvent-free process. Instead of using a conventional PVDF (polyvinylidene fluoride) binder, we employed a phenoxy resin as the binder in dry process for the first time. This thermoplastic binder exhibits better ductile properties than PVDF in the way that it generates a uniform network structure that connects the active materials during the hot press process. This enables the production electrochemically stable electrodes without using organic solvents, which record capacity retention rates of 73.5% over 50 cycles at a 40 mg/cm2 of thick electrodes. By contrast, thick electrodes produced with a PVDF binder via wet processing only have a capacity retention rate of 21.8% due to rapid structural degradation.

Influence of warm isostatic press (WIP) process parameters on mechanical properties of additively manufactured acrylonitrile butadiene styrene (ABS) parts

Owing to the deposition mechanism, parts fabricated from the material extrusion (ME) process have intrinsic air gaps that negatively impact their mechanical properties. Thus, the amount of air gaps should be minimized. In this study, a warm isostatic press (WIP) process was adopted to decrease the amount of air gaps, resulting in improved mechanical properties using acrylonitrile butadiene styrene (ABS). To identify changes in the mechanical properties, tensile tests were performed with specimens heat-treated by the WIP processes with different pressure–temperature profiles. The influence of the temperature and pressure on tensile strength, elongation at break, and toughness was investigated. Water tightness evaluation was conducted to prove the decrease in the air-gap size. Based on the investigation, the WIP process was concluded to be effective for decreasing the intrinsic air gaps and improving the mechanical properties owing to the increase of the bonding force between the lines and layers, which led to the suggestion of a method that optimizes the parameters of the WIP process.

A real-time analysis system for filtrate state in plate-and-frame filter press process based on the machine vision

Filtrate state analysis is an essential guideline for intelligent monitoring and control of the filter press process in plate-and-frame filter presses. Currently, the majority of filtrate analysis depends on manual detection, observing the turbidity and flow state of filtrate. Since the filtration procedure is time-consuming, the functioning status of the plate-and-frame filter press cannot be sent back in real-time through manual filtrate detection. Therefore, it is necessary to develop a rapid and efficient analysis method to monitor the turbidity and flow of filtrate in the plate and frame filter press process. In this study, an object detector based on the convolutional neural network with multi-label learning was proposed to analyze the turbidity and flow of filtrate simultaneously in real-time. Owing to the different durations of the various filtrate states during actual production, the soft label was introduced to alleviate the effects of imbalanced samples. In addition, a tracking module is connected to the object detector, which aims to provide a foundation for stably analyzing the filtrate state over a period. The proposed method has been evaluated in a comprehensive manner using huge amounts of filtrate images taken in an actual production process. The experimental results illustrate the effectiveness of the multi-label learning and tracking module. The superiority and working mechanisms of the soft label are both explained through a series of quantitative and qualitative analyses.

Effect of the fabrication process on the superconducting properties of Pb-BSCCO

Bismuth based high Tc superconductors are among the materials that have been extensively appreciated in terms of their application. Since this type of superconductors are very sensitive with respect to synthesis process, here, we consider effect of synthesis process on the electrical, magnetic and superconducting properties of Pb-BSCCO compound. The samples were prepared by both solid state and sol-gel reaction. In both of the preparation routes, two different methods of Cold Press (CP) and Spark Plasma Sintering (SPS) were used to compress the samples after, the completion of their calcination and grinding. In the next step, the samples put through the thermal process of sintering with different temperatures with respect to their preparation method. The results of the measurements indicate better superconducting properties in sol-gel method compare to the solid-state method. Also, it indicates better superconducting properties in Cold Press samples with respect to the samples prepared by SPS method. To compare the sintering temperature indicates that 825 and 830 oC are suitable temperature for sol-gel and solid-state samples, respectively, in Cold Press process.

ε-Poly-l-lysine-modified natural silk fiber membrane wound dressings with improved antimicrobial properties

Many complex diseases, such as bacterial infections, frequently accompany cutaneous wound healing, adding to the difficulty of clinical wound management. Consequently, in addition to displaying strong biocompatibility and actively promoting wound healing, an optimal wound dressing should also possess antimicrobial qualities to address issues with bacterial infection. This paper developed natural silk fiber (SF) membranes (also known as a flat silk cocoon (FSC)) with antimicrobial properties as a dressing for skin wounds. By changing the spinning tools and environment of silkworm larvae, a novel natural SF membrane with a cocoon structure and controllable size was prepared. The functional SF membranes were obtained via a hot press process and grafted with ε-Poly-l-lysine (EPL). The results showed that the SF membrane dressing was adjustable in size with a similar structure to the extracellular matrix (ECM), displaying inherent mechanical properties, excellent antimicrobial qualities, and biocompatibility. In vivo experiments using a full-thickness skin defect model indicated that EPL-modified SF membranes significantly promoted the rate of wound healing, exhibiting thicker granulation tissue and higher collagen disposition than commercial dressings (Tegaderm™ film). Therefore, the excellent mechanical qualities and cytocompatibility of the antimicrobial EPL-modified SF membranes substantially promote their potential application as a chronic wound dressing.

Research on hot isostatic pressing process of CFETR WCCB components

Chinese Fusion Engineering Test Reactor (CFETR) is a superconducting magnet tokamak reactor of equivalent size and complementary functionality to that of ITER. The water-cooled ceramic breeder (WCCB) breeder blanket designed by the Institute of Plasma Physics, Chinese Academy of Sciences is one of the candidate breeder blanket concepts for CFETR. As an important part of the fusion reactor, the WCCB directly determines the safe operation of the fusion reactor. In the WCCB manufacturing technology, the hot isostatic pressing (HIP) process is applied to the manufacture of WCCB due to its unique technical characteristics. This paper introduces the process research and inspection during the development of WCCB components, and the results will be the guidance for the manufacture of WCCB Components.

Effective Extraction of the Al Element from Secondary Aluminum Dross Using a Combined Dry Pressing and Alkaline Roasting Process.

Secondary aluminum dross (SAD) is a hazardous solid waste discharged from aluminum electrolysis and processing and the secondary aluminum industries, which causes severe environmental pollution and public health disasters. The stable presence of the α-Al2O3 and MgAl2O4 phases in SAD makes it difficult for it to be efficiently utilized. A combined dry pressing and alkaline roasting process was proposed for extracting the valuable Al element from SAD. Two alkaline additives (NaOH and Na2CO3) were selected as a sodium source for extracting the aluminum source from SAD in order to perform the thermodynamic analysis and roasting experiments. The phase transition behavior and the leaching performance tests were conducted using X-ray diffraction, scanning electron microscopy, X-ray fluorescence, leaching kinetics and thermal analysis. The recovery of Al and Na reached the values of 90.79% and 92.03%, respectively, under the optimal conditions (roasting temperature of 1150 °C, Na2CO3/Al2O3 molar ratio of 1.3, roasting time of 1 h, leaching temperature of 90 °C, L/S ratio of 10 mL·g−1 and leaching time of 30 min). Meanwhile, the removal efficiency of N and Cl reached 98.93% and 97.14%, respectively. The leaching kinetics indicated that the dissolution of NaAlO2 clinkers was a first-order reaction and controlled by layer diffusion process. The green detoxification and effective extraction of the Al element from SAD were simultaneously achieved without any pretreatments.

Application of Finite‐Element Simulation and Neural Networks in the Prediction of Metal Flow Behavior during the Sizing Press Process

A dog‐bone profile is developed by inhomogeneous deformation of a slab, whose parameters can be used to describe the metal flow rule during the width reduction process by a sizing press. The accuracy of a dog‐bone profile is essential to ensure the high width precision of the roughing process. However, the existing equipment cannot satisfy the requirements of online measurement. To solve this problem, herein, a prediction model for dog‐bone parameters based on the finite‐element simulation and a neural network is presented. The finite‐element simulation can reproduce the field production process, revealing variations in the dog‐bone profile parameters. In addition, based on the simulation data, a neural network model is constructed to predict the dog‐profile parameters. By adjusting the hyperparameters, the prediction accuracy of the constructed deep neural network model with two hidden layers is improved. For the dog‐bone profile parameters, the mean squared error is less than 3 mm, the mean absolute percentage error is less than 2%, the maximum absolute percentage error is less than 9%, and the root mean squared error is less than 4 mm. Thus, an accurate prediction of the dog‐bone profile parameters is achieved, which can guide subsequent high‐precision width control.

Polymer/carbon pin through thickness reinforcement

ABSTRACT This work discusses the development and refinement of a polymer/fibre through thickness reinforcement method. Similar in initial concept to the traditional metalworking process of riveting this allows the manufacture of through thickness reinforced 2-D preforms. Pins are placed with deliberate excess length using a veterinary needle to part in-plane fibres. A lay-up with an array of pins is then subjected to a hot-press process flattening the pin ends resulting in a consolidated preform. This preform exhibits useful characteristics such as the ability to be cut and reformed to a new topology, with the through thickness reinforcement also conforming to the new shape. Refinements to the process introduce a multi-stage press process aimed at improving pin orientation with both original and refined processes evaluated using ASTM D5528 to determine the effect on interlaminar fracture toughness.

Deformation mechanism and quantitative characterization of Al2O3 inclusions in powder metallurgy superalloys

By means of implanting inclusions artificially, the evolution law of three-dimensional morphology and size of Al2O3 inclusions in FGH96 powder metallurgy (PM) superalloy during hot iso-static pressing (HIP), hot extrusion (HEX) and hot isothermal forging (HIF) process was investigated by SEM and quasi in situ Micronano-CT. The size change of inclusions during different stages was studied quantitatively, the three-dimensional (3D) morphology of the inclusions was characterized, and the deformation mechanism was proposed. The results showed that the inclusions in powder stage were long stripe or plate-like shape. During HIP, Al2O3 inclusions were mechanically bonded to the alloy matrix, and its chemical composition, morphology and size remained unchanged. During HEX, Al2O3 inclusions were broken and elongated into chain shape due to shear stress. The quantitative relationship between inclusion size after extrusion and extrusion ratio as well as original inclusion size was established. During HIF, the relationship between 3D morphology, size, orientation and deformation of a single inclusion during forging compression was quantitatively characterized by quasi in-situ micronano-CT for the first time. The above evolution law provides theoretical basis and technical support for improving the purity level of powder turbine disk.

The effect of ionic strength and pH on the dewatering rate of cellulose nanofibril dispersions

Cellulose nanofibrils, CNFs, show great potential in many application areas. One main aspect limiting the industrial use is the slow and energy demanding dewatering of CNF suspensions. Here we investigate the dewatering with a piston press process. Three different CNF grades were dewatered to solid contents between approx. 20 and 30%. The CNF grades varied in charge density (30, 106 and 604 µmol/g) and fibrillation degree. The chemical conditions were varied by changing salt concentration (NaCl) and pH and the dewatering rates were compared before and after these changes. For the original suspensions, a higher charge provides slower dewatering with the substantially slowest dewatering for the highest charged CNFs. However, by changing the conditions it dewatered as fast as the two lower charged CNFs, even though the salt/acid additions also improved the dewatering rate for these two CNFs. Finally, by tuning the conditions, fast dewatering could be obtained with only minor effect on film properties (strength and oxygen barrier) produced from redispersed dispersion. However, dewatering gives some reduction in viscosity of the redispersed dispersions. This may be a disadvantage if the CNF application is as e.g. rheology modifier or emulsion stabilizer.Graphical abstract

PRODUCTION MASK SCUBA TYPE ON UMKM CAHAYA PRINTING

Scuba mask is a type mask which made from a tight and elastic type of fabric that provides comfort when used. PT. Cahaya Digital Printing is one of companies engaged in digital printing that produces masks which are currently used by the public. The purpose of this study was to analyze production process of scuba masks from raw materials to mask products. The scuba mask production process uses scuba cloth as raw material which though a printing process on a digital printing machine which has a print area of up to 1.5 m with a print speed of up to 15 m2 per hour to print according design to customer requirement, manual press process to cut the mask to size and scuba printing and sewing and overlay processes using a sewing machine that has a stitch length of 0-5 mm and a sewing speed of up to 4500 s.p.m to sew the edges of the mask to make look neat and not stringy.

Influence of Strain Rates during Severe Plastic Strain Processes on Microstructural and Mechanical Evolution in Pure Zinc.

The study presents an analysis of the influence of the plastic strain rate on the mechanical and structural properties of pure zinc. Thanks to the use of unconventional methods of plastic processing, the process of the equal channel angular pressing (ECAP) and the process of hydrostatic extrusion (HE), the tests were performed in a wide range of plastic strain rates, between 0.04 s−1 and 170 s−1. Plastic strain rate changes were carried out in the course of the significant plastic strain processes, and not on previously deformed samples. All tests were carried out at a constant value of plastic strain rate, ε ~ 2. A strong influence of the plastic strain rate on changes in the microstructure in zinc was observed during the tests. For the rates in the range of 0.04 s−1 to 0.53 s−1 its bimodal nature was observed, and in the range of 7 s−1 to 170 s−1 high homogeneity and evenness of grains related to the processes of continuous dynamic recrystallization was noticed. The effect of the strong homogenization of the microstructure was the increase in mechanical properties, yield point and tensile strength to the maximum values of UTS = 194 MPa, YS = 145 MPa at a strain rate of 170 s−1. Compared to the material with a bimodal microstructure, an over seven-fold increase in the elongation value was observed.

TIME ANALYSIS OF THE MIXING PROCESS OF FIRE BRICK MATERIALS IN PT. BENTENG API TECHNIC GRESIK

PT. Benteng Api Technic is a leading refractory company in Indonesia with refractory bricks as one of its superior products. The process of making refractory bricks that will be observed in this study is the process of mixing materials and the molding process. In the mixing process, there are no tools in the form of time indicators to help operators make decisions about the mixing time of ingredients. This research aims to obtain the time for the mixing of materials with maximum mixing quality and to support the press process optimally. The research was conducted using a perfectly randomized experimental design in order to obtain different mixing results based on the nine selected mixing time treatments. Measurement of working time is carried out using the stopwatch time study method on press operators who are experienced in their fields. Calculations to align the two processes using a Gantt chart with idle time as an indicator. The experimental results revealed that the most optimal mixing with a mixing time of 12 minutes resulted in 7.2 kilograms of mass that did not pass through an 18 mesh sieve. Based on the results of the gantt chart, the use of 11 mixing time for material B resulted in the lowest idle time of 178 minutes. The processing time obtained is expected to be used as a guide in determining the time input on the time indicator tool in the process of mixing refractory bricks.

Numerical simulation and verification of hot isostatic pressing densification process of W-Cu powder

Based on finite element method (FEM) and the plasticity theory, a numerical model is built to simulate the hot isostatic pressing (HIP) process of W-Cu powders, and the densification law of the compact in the process is analysed. The cross-experiment method is used to formulate an orthogonal optimization plan for the insulation temperature, the holding pressure and the insulation holding time. The contour map diagram of the relative density in the temperature and pressure plane is established, and the optimal parameter scheme is proposed by simulation results. Experiments are carried out under the best HIP scheme. Comparison of experimental results with simulation results indicates that the numerical model is accurate. The results indicate that the densification process of the compact is from the edge to the centre. The optimal hot isostatic pressing parameter scheme obtained by simulation is 950 °C/110 MPa/2 h, and the overall relative density of the compact can reach more than 96% under this scheme. Under optimal scheme, the maximum error between the simulation results and the test results of the relative density is 1.28%, whereas the average error is about 0.3%.