Curing Process Research Articles

Experimental study and numerical simulation of short- and long-term shear stress relaxation behaviors of magnetorheological elastomers

An experimental study and numerical simulation of short- and long-term shear stress relaxation behaviors of nonaligned and aligned magnetorheological elastomers (MREs) were investigated. The aligned MRE was created by aligning micro-size carbonyl iron particles in chains in silicon rubber using an external magnetic field during the curing process, while the nonaligned MRE was fabricated without applying a magnetic field. The effects of permanent magnetic fields on the shear stress relaxation of the nonaligned and aligned MREs were examined using the double-lap shear stress relaxation test with a short-term period of 1200 s and a long-term period of 1.08×106 s. The shear stress and relaxation modulus of the nonaligned and aligned MREs increased considerably with the rise of magnetic flux density to about 500 mT and then enhanced slightly above 500 mT. The shear stress and relaxation modulus of the aligned MRE were considerably higher than those of the nonaligned one. The shear stress relaxation of the nonaligned and aligned MREs was numerically simulated using the fractional derivative viscoelastic Kelvin–Voigt model. The model parameters were identified by fitting the relaxation modulus to the short-term measured data of the MREs. The shear stress estimated from the investigated model with fitted parameters was in excellent agreement with the short-term experimental data of the MREs measured under different magnetic fields. Besides, the short-term model-fitted parameters were used to predict the long-term shear stress relaxation of the nonaligned and aligned MREs. The largest difference between model-predicted and long-term measured results for the nonaligned and aligned MREs was less than 1%. Therefore, the studied model can be used to predict the long-term shear stress relaxation of the nonaligned and aligned MREs.

Preparation of Highly Stable Wood with Fast Curing, Ultraviolet, and Mildew Resistance through Copper-Montmorillonite Nanoparticles Hybridized with Tung Oil.

Wood has a number of undesirable inherent properties that limit its ability to be used in a wider range of applications. For this reason, in this study, copper-montmorillonite nanoparticles were prepared from natural biomass tung oil and the natural mineral montmorillonite by the ion exchange method. Modified wood with tung oil intercalated with copper-montmorillonite was prepared by a simple and environmentally friendly impregnation and natural curing process. The natural curing rate of tung oil was greatly accelerated by the addition of copper-montmorillonite nanoparticles. The surface contact angle of the wood increased from 85.0° to 152.2° after copper-montmorillonite-tung oil treatment, and remarkably, it remained at 144.2° after 180 s. After 192 h of immersion, the water absorption decreased by 90.0% compared with the control group, of which the resistance to swelling was as high as 59.00%, which significantly improved the dimensional stability of the wood. After 15 days of ultraviolet irradiation, the copper-montmorillonite-tung oil-treated wood showed a 68.89% reduction in redness value compared to the control and a significant increase in ultraviolet resistance. Copper-montmorillonite-tung oil-treated wood showed greatly enhanced effectiveness against mildew. On the eighth day of Aspergillus niger infestation, the control wood was already full of mildew, whereas the copper-montmorillonite-tung oil-treated wood was not infested with mildew. In particular, after 28 days of infestation by Penicillium oryzae, the modified wood remained free of the fungus, with 100% mildew prevention efficiency. In addition, after 2 weeks of leaching, the leaching rate of the impregnated material was only 0.22%, facilitating long-term protection of the wood. The present study by the copper-montmorillonite synergistic tung oil treatment strategy provides innovative methods and potential ideas for extending the service life of wood products and high-value utilization of wood and also has the potential to scale up wood protection.

Enhanced water resistance in post‐crosslinked polyurethane dispersion films using ethylene glycol diglycidyl ether

AbstractA post‐crosslinked polyurethane dispersion (PUD) with excellent water resistance was prepared using ethylene glycol diglycidyl ether (EGDGE) as a crosslinker. An anionic PUD was synthesized using dimethylol propionic acid as an internal emulsifier. During the curing process of the PUD film, the hydrophilic carboxylic acid and amine groups of PUD were consumed by the reaction with EGDGE. The reduction of hydrophilic functional groups and the increase of the crosslinking density effectively improved the water resistance of PUD films. In addition, the tensile strength of the PUD film increased from 54.2 MPa to a maximum of 75.3 MPa. The crosslinked structure reduced the crystallinity of the PUD film, which led to an increase in transparency.Highlights Novel EGDGE‐crosslinked PUD films with enhanced water resistance were developed. PUD samples introduced with EGDGE indicated favorable storage stability. Crosslinking reduced hydrophilic groups, improving thermal and mechanical stability. Optimized EGDGE content (6 wt%) yielded maximum tensile strength (75.3 MPa). Transparency increased due to suppressed phase separation in crosslinked PUDs.

FBG-Based UV-Curing Kinetics Analysis by Exothermic Behavior

Since photo-induced polymerization of the ultra-violet (UV)-curing adhesive from a fluid state to a solid state is an exothermic process, the UV curing exothermic behavior can be regarded as a potential evaluation methodology to analyze UV-curing kinetics. Herein, a fiber Bragg grating (FBG)-based UV curing exothermic behavior monitoring is proposed to evaluate the UV-curing dynamic process and analyze a series of thermal and mechanical properties changes during curing. The exothermic behavior of the UV curing adhesive during curing and the feasibility of FBG-based curing kinetic analysis scheme are verified experimentally, full cycle cure monitoring of the UV curing adhesive can be realized by this FBG-based curing kinetic analysis scheme, and the UV-curing kinetics of four different types of the UV curing adhesive are corresponding to different exothermic behaviors. Compared with curing process evaluation based on refractive index variation, this FBG-based exothermic behavior monitoring has the ability to extract more details of the curing process, and some curing stages with negligible refractive index changes also can be distinguished. By using this proposed scheme, the UV-curing dynamic process and multiple characteristic parameters, such as curing time, time constant, transient temperature rise, and residual stress, can be evaluated, which may contribute to evaluating and analyzing UV-curing kinetics more comprehensively.

Characterization of Self-Cured Silicone Oils for Encapsulation of Ultraviolet-C Light-Emitting Diodes.

The effectiveness of ultraviolet-C light-emitting diodes (UVC LEDs) is currently limited by the lack of suitable encapsulation materials, restricting their use in sterilization, communication, and in vivo cancer tumor inhibition. This study evaluates various silicone oils for UVC LED encapsulation. A material aging experiment was conducted on CF1040 (octamethylcyclotetrasiloxane), HF2020 (methyl hydro polysiloxanes), and MF2020-1000 (polydimethylsiloxane) under UVC radiation for 1000 h. The analysis assessed transmittance changes and chemical composition alterations throughout the aging process. Notably, HF2020 showed an increase in transmittance before 500 h, indicating a curing process attributed to the photolysis of Si-H, leading to the formation of Si-O-Si. Further testing on 265 nm UVC LEDs, both with and without HF2020 encapsulation, showed that the encapsulated LEDs exhibited a remarkable maximum increase of 27% in radiant power compared to their unencapsulated counterparts. Additionally, these encapsulated LEDs sustained higher radiant power levels during the first 200 h of operation. Notably, its potential application in photodynamic therapy is significant; by activating photosensitizers with higher UVC exposure, it facilitates the rapid production of reactive oxygen species, leading to effective cancer cell destruction within a short timeframe.

Oscillation rheometry of curing process of epoxy binders modified with polyetherimide

Objectives. The aim of this study is to ascertain the influence of polyetherimide on the curing process of epoxy binders.Methods. The storage modulus and loss modulus of epoxyamine systems were measured as a function of curing time on the Anton Paar MCR 302 rheometer. The experiments were carried out at an oscillation frequency of 1 Hz, with an amplitude aligned with the linear viscoelasticity region, and across a range of temperatures (160, 170, and 180°C). The crossover point was determined when the components of the complex modulus of elasticity are equal according to the obtained dependencies.Results. The influence of polyetherimide on the curing process of epoxyamine binders was investigated at a thermoplastic content of 5 to 20 pts. wt at three temperatures. In a system modified with 20 pts. wt of polyetherimide, phase separation was observed during the curing process. In systems modified with 10 and 20 pts. wt of polyetherimide, the limiting value of the modulus of elasticity was observed to be higher at 170°C than at 180°C.Conclusions. The modification of epoxyamine binders with thermoplastic in an amount of 5–20 pts. wt has been observed to extend the time required to reach the crossover point. Furthermore, the curing process markedly slows down in the system comprising 10 pts. wt of thermoplastic content, in which it takes the longest time to reach the crossover point at all three experimental temperatures.

Fracture Toughness of Winding Carbon Plastics Based on Epoxy Matrices and Reinforced by Polysulfone Film.

In this work, the fracture mechanism of winding carbon-fiber-reinforced plastics (CFRPs) based on epoxy matrices reinforced by polysulfone film was investigated. Two types of polymer matrices were used: epoxy oligomer (EO) cured by iso-methyltetrahydrophthalic anhydride (iso-MTHPA), and EO-modified polysulfone (PSU) with active diluent furfuryl glycidyl ether (FGE) cured by iso-MTHPA. At the winding stage, the reinforcing film was placed in the middle layer of the CFRP. The fracture toughness GIR of the obtained CFRP was determined by the double-cantilever beam delamination method. Additionally, the effect of cyclic loading on the fracture toughness of CFRP reinforced with polysulfone film was investigated. It was shown that heterogeneous structures arising from the dissolution of the polysulfone film in the epoxy binder during the curing process increase the fracture toughness of CFRP from 0.5 kJ/m2 to 1.2 kJ/m2. Application of cyclic loads had little effect on the fracture toughness value. As a result of this study, it was revealed that the macrocrack propagates near the reinforcement layer along the diffusion zone, which has a phase organization of the type PSU matrix-EO dispersion.

Interlaminar Fracture Toughness Analysis for Reliability Improvement of Wind Turbine Blade Spar Elements Based on Pultruded Carbon Fiber-Reinforced Polymer Plate Manufacturing Method.

The key structural components of a wind turbine blade, such as the skin, spar cap, and shear web, are fabricated from fiber-reinforced composite materials. The spar, predominantly manufactured via resin infusion-a process of resin injection and curing in carbon fibers-is prone to initial defects, such as pores, wrinkles, and delamination. This study suggests employing the pultrusion technique for spar production to consistently obtain a uniform cross-section and augment the reliability of both the manufacturing process and the design. In this context, this study introduces carbon fiber-reinforced polymer (CFRP/CFRP) and glass fiber-reinforced polymer (GFRP/CFRP) test specimens, which mimic the bonding structure of the spar cap, utilizing pultruded CFRP in accordance with ASTM standards to analyze the delamination traits of the spar. Delamination tests-covering Mode I (double cantilever beam), Mode II (end-notched flexure), and mixed mode (mixed-mode bending)-were performed to gauge displacement, load, and crack growth length. Through this crack growth mechanism, the interlaminar fracture toughness derived was examined, and the stiffness and strength changes compared to CFRP based on the existing prepreg manufacturing method were analyzed. In addition, the interlaminar fracture toughness for GFRP, which is a material in contact with the spar structure, was analyzed, and through this, it was confirmed that the crack behavior has less deviation compared to a single CFRP material depending on the stiffness difference between the materials when joining dissimilar materials. This means that the higher the elasticity of the high-stiffness material, the higher the initial crack resistance, but the crack growth behavior shows non-uniform characteristics thereafter. This comparison provides information for predicting interlaminar delamination damage within the interior and bonding area of the spar and skin and provides insight for securing the reliability of the design life.

Ply Optimization of Composite Laminates for Processing-Induced Deformation and Buckling Eigenvalues Based on Improved Genetic Algorithm.

The structure of thermoset composite laminated plates is made by stacking layers of plies with different fiber orientations. Similarly, the stiffened panel structure is assembled from components with varying ply configurations, resulting in thermal residual stresses and processing-induced deformations (PIDs) during manufacturing. To mitigate the residual stresses caused by the geometric features of corner structures and the mismatch between the stiffener-skin ply orientations, which lead to PIDs in composite-stiffened panels, this study proposes a multi-objective stacking optimization strategy based on an improved adaptive genetic algorithm (IAGA). The viscoelastic constitutive model was employed to describe the modulus variation during the curing process to ensure computational accuracy. In this study, the IAGA was proposed to optimize the ply-stacking sequence of L-shaped stiffeners in composite laminated structures. The results demonstrate a reduction in the spring-in angle to 0.12°, a 50% improvement compared to symmetric balanced stacking designs, while the buckling eigenvalues were improved by 20%. Additionally, the IAGA outperformed the traditional non-dominated sorting genetic algorithm (NSGA), achieving a threefold increase in the Pareto solution diversity under identical constraints and reducing the convergence time by 70%. These findings validate the effectiveness of asymmetric ply design and provide a robust framework for enhancing the structural performance and manufacturability of composite laminates.

Comparative Study of Gradient Polymer Composite and Blend Polymer Composite for Ultra‐Precision Machine Tools

ABSTRACTExhibiting excellent mechanical properties and exceptional vibration reduction performance, polymer composite (PC) has garnered significant research interest in various industries, particularly in ultra‐precision machining (UPM) machine tool beds. UPM machine tools have a stringent requirement on the comprehensive performance of the bed materials. Specially, the materials of machine tool bed must possess both high mechanical properties and outstanding damping characteristics. However, a major obstacle hindering the widespread adoption of PC in UPM machine tool beds is the difficulty in achieving optimal mechanical properties and vibration reduction simultaneously with the same material composition and curing process conditions. In this study, the effect of various particulates on the mechanical strength, loss factor and the average thermal expansion coefficient of PC were systematically investigated. The experimental findings revealed that the compressive strength of PC improved by the incorporation of particulates. Nevertheless, the flexural strength and tensile strength of PC display an inverse variation. Subsequently, gradient PC and compound PC were designed based on the aforementioned results to achieve the best overall properties for the machine tool bed material. The experimental results highlighted that the left and right tri‐gradients materials (L‐R‐3) exhibited the outstanding comprehensive performance. Moreover, this study provides beneficial information to improve the comprehensive properties of PC. Furthermore, it is of great significance to improve machining accuracy of UPM and increase the machining stability of UPM.

The Use of Reinforced Concrete for Durable and Aesthetic Sports and Recreational Sports

This study focuses on the design and construction of durable recreational seating using reinforced concrete, addressing the limitations of traditional materials such as wood and metal, which are prone to environmental degradation and high maintenance costs. Reinforced concrete is known for its durability, strength, and resistance to harsh weather conditions, making it an ideal material for public seating in outdoor environments. Several key tests were conducted to assess the performance of the concrete mix used in this project. Sieve analysis confirmed that the fine and coarse aggregates were well-graded, ensuring optimal compaction and strength. The slump test,conducted with a water-cement ratio of 0.6, produced a slump value of 150 mm, indicating medium workability. This level of workability is suitable for concrete that requires easy placement and proper compaction without segregation or excessive bleeding. The compressive strength test at 7 days yielded a compressive strength of 15.81 MPa, demonstrating the early strength development of the concrete. However, compressive strength results for the 14-day and 28-day tests are still pending, as the remaining cubes are currently in the curing tank. These results will provide further insights into the long-term strength and performance of the concrete once the curing process is completed. Preliminary findings suggest that reinforced concrete is an excellent choice for recreational seating due to its ability to provide long-lasting durability and reduced maintenance. The combination of well-graded aggregates, an optimal water-cement ratio, and promising early compressive strength indicates that this material will perform well under both static and dynamic loads typically encountered in public seating.

Fabrication and Performance Enhancement of Wood Liquefaction-Based Carbon Fibers Modified with Alumina Nanoparticles.

In this paper, alumina-modified wood liquefaction (AL-WP) was prepared by blending nano-alumina (Al2O3) into wood liquefaction phenolic resin (WP) using a co-blending method. Alumina-modified wood liquefaction protofilament fiber (AL-WPF) was obtained by melt-spinning, curing, and thermo-curing processes, which were followed by carbonization to obtain alumina-modified wood liquefaction carbon fiber (AL-WCF). This paper focuses on the enhancement effect of nano-alumina doping on the mechanical properties and heat resistance of wood liquefaction carbon fiber (WCF), explores the evolution of graphite microcrystalline structure during the high-temperature carbonization process, and optimizes the curing conditions of AL-WPF. The results showed that the introduction of Al2O3 significantly improved the mechanical properties and heat resistance of carbon fibers. When 1.5% Al2O3 was doped and carbonized at 1000 °C, the tensile strength of AL-WCF was increased from 33.78 MPa to 95.74 MPa, there was an enhancement of 183%, its residual carbon rate could reach 79.2%, which was better than that of the undoped wood liquefaction (WCF), and it exhibited a more substantial heat-resistant property. In addition, the best curing process for alumina nanoparticle wood liquefiers was obtained by optimizing the curing conditions: hydrochloric acid concentration of 16%, formaldehyde concentration of 18.5%, temperature increase rate of 15 °C/min, holding time of 3 h, and holding temperature of 100 °C. These studies provide a theoretical basis and technical support for developing and applying carbon fibers from alumina-modified wood liquefiers.

STUDI TERMAL PADA SEGMEN CETAKAN CROWN PADA MESIN CURING DALAM PROSES PRODUKSI BAN MOBIL DI PT. ELANG PERDANA TYRE INDUSTRY

The curing process is a stage in car tire molding carried out under high temperature and pressure. One of the key components in this process is the crown mold segment, which functions to shape the tread pattern on the tire. This study aims to analyze the heat distribution in the crown mold segment using Solidworks software, focusing on material specifications, heat distribution patterns, and simulation parameters affecting the results. The material used is Steel AISI 1020. The simulation results indicate an even heat distribution with an initial temperature of 453 K, convection ranging from 179.933°C to 179.967°C on the side area, and 179.916°C to 179.950°C on the tread pattern. Heat transfer rates were recorded as 96,323.28 W through conduction, 898.452 W through convection, and 2.56 W through radiation. Key parameters influencing the simulation include the initial material temperature (453 K), convection coefficient (10 W/(m²·K)), radiation emissivity (0.3), and ambient temperature (300 K).

Study on temperature gradient of ultra-thick foam sandwich composite structure during curing

This paper conducts numerical simulations and experimental measurements on the temperature distribution of ultra-thick foam sandwich composite structure with varying ply thicknesses, aiming to investigate the influence of prepreg ply thickness on the temperature gradient of foam sandwich structure. Firstly, the curing kinetic of CYCOM970/T300 prepreg was studied using non-isothermal differential scanning calorimetry (DSC). Then, thermal analysis of foam sandwich composite structure with different ply thicknesses was conducted using ABAQUS software combined with user subroutines. Subsequently, thermocouple sensors were used to measure the curing temperature of foam sandwich structure. The results indicate that the prepreg ply thickness has a significant impact on the temperature gradient during the curing process of foam sandwich structure. When there are a larger number of prepreg plies, overheating of the prepreg on the foam upper layer occurs, resulting in a significant temperature gradient in the thickness direction of the structure. In this case, reducing the heating rate of the autoclave curing process can effectively reduce the temperature overshoot of the prepreg on the foam upper layer.

Effect of curing temperature on the soil physical and mechanical properties on clay shale geopolymer fly ash stabilization

Clay shale is an easily degraded mudrock when exposed to weathering. The reduced strength due to degradation can be mitigated through soil stabilization. In recent years, soil stabilization using geopolymers has become one of the latest popular methods due to its economic benefits and lower carbon footprint. A widely used cementitious material for this method is fly ash-based geopolymer. The relationship between curing temperatures and the performance of clay shale stabilized with fly ash-based geopolymer has yet to be studied for the purpose of identifying a more effective stabilization method. In this study, clay shale was stabilized using geopolymer. The geopolymer was made of fly ash and an activator. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as activators. The activator is diluted with water to create a 12 M mixture. Before the unconfined compressive strength test, the specimens were subjected to various curing temperatures from 26oC to 60oC. The test result shows that, in general, higher curing temperatures increased the dry density from 1.66 g/cm3 to 1.84 g/cm3. Meanwhile, the unconfined compressive strength multiplies about 3.5 times. Furthermore, the moisture content decreased after the curing process from 19% to 2.5%. This led to the specimen volume experiencing decrement due to the shrinkage during the curing period. The volume reduces from 67.7 cm3 to 63.5 cm3. In general, temperature plays a significant role in enhancing the strength of clay shale stabilized using fly ash-based geopolymer.

Relationship between physicochemical properties, non-volatile substances, and microbial diversity during the processing of dry-cured Spanish mackerel.

To meet the demand of consumers for high-quality dry-cured fish. This study investigates the relationship between microbial diversity and the changes in physicochemical properties and non-volatile flavor compounds of dry-cured Spanish mackerel (DCSM) throughout the curing process. Our findings demonstrate that moisture content significantly decreased during curing, while NaCl generally increased. The nitrite level of 1.52mg/kg, meeting national safety standards. Additionally, there was a significant increase in hardness and chewiness. The synergistic effect of glutamic acid (Glu), alanine (Ala), and histidine (His) with inosine monophosphate (IMP), adenosine monophosphate (AMP) and guanosine monophosphate (GMP) enhanced the umami taste. Proteobacteria and Photobacteria are the main microorganisms of DCSM at the phylum and genus levels. Proteobacteria and Photobacteria are the main microorganisms of DCSM at the phylum and genus levels. Photobacterium, Moritella, and Pseudomonas were positively correlated with AMP, GMP, Ala, and Glu. And negatively correlated with nitrite and TBARS. These findings suggest that specific microorganisms positively influence the quality of DCSM through their metabolic activities. This research enhances our understanding of flavor formation mechanisms and provides critical insights for optimizing DCSM processing and quality control.

A simple and versatile photothermal dual-curing system design based on phytophenol derivatives and thiol chemistry for potential electronic encapsulant application

Given the diversity of thiol chemistry, researchers are actively exploring its potential as a versatile compound. This paper presents the synthesis of three bio-based multifunctional monomers (EPMG, EPBEG, EPBEF) containing allyl and epoxy groups using phytophenols (magnolol and eugenol) as raw materials. Photothermal dual curing was performed using pentaerythritol tetrakis(3-mercaptopropionate) (PETMP). Comprehensive studies and comparisons of the cured systems were conducted, including curing kinetics, mechanical properties, dielectric properties, and transmittance. The effect of the curing sequence was systematically investigated. The results demonstrate that as the curing proceeds, the mechanical properties and glass transition temperature (Tg) of the material improve significantly, and the dual curing process exhibits excellent bonding, dielectric, and ultraviolet (UV) shielding performance. Moreover, the differences in monomer structure (methoxy, benzene ring connection) also impact the properties of the monomers and the performance of the material. This work provides a novel approach to designing epoxy monomer structures and developing bio-based single-component dual-curing systems. This thiol-mediated dual-curing system has potential applications in electronic materials and personal protective equipment can contribute to achieving miniaturization, precision, and integration in various applications.

Kinetics analysis of radical photopolymerizations for UV-curable nanocomposites based on cellulose nanocrystals: Promoting and enhancing mechanisms.

The interfacial interactions between the enhanced nanoscale components and the polymer matrix, as well as the photopolymerization behavior of the composite system, are of paramount importance to the quality and performance of photo-curable nanocomposites. Cellulose nanocrystals (CNCs), a novel class of green reinforcing materials, are anticipated to facilitate the development of high-performance applications of advanced functional materials. Herein, the promoting and enhancing effects of modified CNCs on photo-curable nanocomposites are studied. As confirmed by the FTIR spectra, the active radicals introduced on the surface of the modified CNCs promote a stronger interfacial chemical interaction between the CNCs and the photopolymer molecules. Infrared thermography is performed to reflect the thermal energy changes during the photocuring of nanocomposites for investigating the acting mechanism of the modified CNCs on the curing behavior. Notably, the nanoscale structure and enhancement effect of CNCs contribute to the effective promotion of the curing reaction of the polymer matrix molecules, and increase their crosslink density. The non-isothermal differential scanning calorimetry (DSC) test is employed to assess the thermal properties of photocured nanocomposites with varying contents of modified CNCs, in order to identify the optimal UV curing process. Kinetic analysis based on the Kissinger model indicates that CNCs not only facilitated the formation of polymer networks, but also played a role in optimizing the reaction paths and reducing the energy barriers of the reactions. The results demonstrated that the 0.75 wt% CNC nanocomposites exhibited the most favorable reactivity at 50 and 100 mW/cm2 UV intensities, which is consistent with the mechanical property test data. In terms of micro-mechanism, the active radicals on the surface enhance the ability of CNCs to chemically bind to the photopolymer. This is coupled with their significant interfacial effects, which facilitate the formation of strong interfacial binding. The aforementioned findings provide a solid foundation for the construction of high-performance photo-curable nanocomposites.

Installation, thermal curing, qualification testing of divertor and position control coils in ADITYA-U tokamak

The former ADITYA, a medium-sized tokamak with a limiter configuration was upgraded to ADITYA-U tokamak with divertor configuration. Two pairs of new divertor coils, a single pair of auxiliary divertor coils and position control coils have been introduced in ADITYA-U tokamak to achieve shaped plasma operation using the existing Toroidal field, Ohmic transformer and vertical field coils. Currently, copper-based continuous transposed conductor (CTC) has been introduced for in-situ winding of the coils. Coil insulation materials are selected to withstand high current (15 kA), high voltage (5 kV) and sustain high temperature (120 °C) during the experiment. The primary challenge was to install the coil with the bus bar using the same conductor without any joints. The design of new divertor coils mainly includes electrical and thermal considerations within the limited space available for installation. A detailed description of the installation of coils, insulation fabrication, insulation curing process and testing of the divertor coils is presented in this paper.

The kinetics of the polyurethane moisture curing reaction: a combined experimental and DFT mechanistic study

An examination of the temporal dynamics of the moisture curing process of polyurethane (PUR) hot melt adhesives under varied humidity (65–85% RH) and temperature (20–40 °C) was performed via in situ Fourier transform infrared (FTIR) spectroscopy.