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The presence of gradient softer outer layers, commonly observed in biological systems (such as cartilage and ocular tissues), as well as synthetic crosslinked hydrogels, profoundly influences their interactions with opposing surfaces. Our prior research demonstrated that gradient-stiffness hydrogel layers, characterized by increasing elasticity with depth, control contact mechanics, particularly in proximity to the layer thickness. We postulate that the distribution of polymers within these gradient layers imparts extraordinary stretch and adhesion characteristics due to network adaptability and stress-induced reorganization. To investigate this phenomenon, we utilized Atomic Force Microscopy nanoindentation to assess the depth-dependent adhesion behavior of polyacrylamide hydrogels with varying gradient layer thicknesses. Two gradient layer thicknesses were achieved by employing different molding materials: glass and polyoxymethylene (POM). Glass-molded hydrogels exhibited a thinner gradient layer alongside a stiffer bulk layer compared to their POM-molded counterparts. In indentation experiments, the POM-molded hydrogel had larger adhesion compared to glass-molded hydrogel. We find that indenting within the gradient layer engenders increased load-unload hysteresis due to heightened fluid transport in the sparse outer polymer network. Consequently, this led to augmented adhesion and work of separation at shallow depths. We suggest that the prominent stretching capability of the sparse outer polymer network during probe retraction contributes to enhanced adhesion. The Maugis–Dugdale adhesive model only fits well to indentations on the thin layer or indentations which engage significantly with the bulk. These results facilitate a comprehensive characterization of adhesion mechanics in gradient-stiffness hydrogels, which could foster their application across emerging contexts in health science and environmental domains. [ABSTRACT FROM AUTHOR]

Tungsten carbide (WC) is one of the most robust mold materials in precision glass molding owing to its excellent hardness at high temperatures. However, the fabrication of a microlens array (MLA) shape on a WC mold is challenging. Electrical discharge machining (EDM) is highly effective in fabricating conductive materials regardless of their hardness. However, due to electrode wear, the machining accuracy and consistency of the MLA are gradually reduced in the EDM process. In this study, a micro copper ball–assembled array electrode (BAAE) was proposed and developed to achieve high efficiency, accuracy, and consistency in MLA mold manufacturing. The copper balls aligned in an array on the position template were used as the electrode to fabricate MLA in EDM. The general calculation method for the maximum service cycles of copper balls was developed to achieve maximum utilization of the copper balls. The in situ rotation of the copper ball updated the processing area, significantly improving the consistency of the lenslet morphology. The effects of two polarity processing were investigated, and the positive processing was chosen. The efficiency of BAAE was significantly improved through the implementation of array alignment and path planning. The effectiveness and efficiency of the ball rotation were confirmed by comparing the lenslet morphology with the ball end–formed electrode. The EDM using BAAE is proven to be capable of improving the efficiency, accuracy, and consistency of MLA mold manufacturing. [ABSTRACT FROM AUTHOR]

Polymeric materials are inexpensive, lightweight, and easy to process. With injection molding technology, they can be used to mass-produce complex geometric products. Although virtual quality measurement systems can prevent product defects, they may not be effective for recycled polymers. Recycling is necessary to achieve sustainable production, but the recycling process can greatly affect material properties. Accordingly, we propose using transfer learning (TL) to apply quality models for virgin materials to recycled materials. Key features from cavity pressure sensor information were extracted as quality indices, and a neural network was trained to predict the part weight and geometric dimensions. TL was then used to fine-tune this pretrained model on data for recycled materials. This method requires little data collection and could greatly reduce the cost of improving quality when using recycled materials. For all quality metrics, the TL model achieved superior performance to a conventional model, even when applied to a 40% smaller dataset; it also converged more quickly and in fewer iterations. A comprehensive analysis indicated that the model had a favorable fit. These results confirm that TL is effective in predicting the quality of injection molding products made with recycled materials; it has superior predictive accuracy and requires less training time than conventional methods. The described process could reduce the cost of implementing process quality inspection systems, incentivizing the use of recycled materials. [ABSTRACT FROM AUTHOR]

Injection molding is a widely utilized manufacturing process across various industries. The cooling time in injection molding is an important factor that affects the productivity and energy consumption of the process. The production efficiency is directly proportional to the cooling efficiency, yet optimizing this cooling process presents significant challenges. The fixed cooling parameters are not suitable for all types of material, thus increasing the molding deviation. To address these challenges, this research work proposed a Regularized with Mish Linear Unit-based Deep Learning Neural Network-based material prediction with optimization of derived variables using the Banana Function-centric Green Anaconda Optimization approach. Initially, the features are extracted from the raw materials, and then the material type is predicted by using Regularized with Mish Linear Unit-based Deep Learning Neural Network. Conversely, various machine properties are clustered utilizing the binomial distribution with damping factor-based farthest first clustering methodology. Subsequently, parameters are derived from both the predicted material and the clustered machine property. The pressure of the machine is controlled by a quasi-conservative with an optimized proportional integral derivative controller. Then, the optimal parameters are selected from the Banana Function-centric Green Anaconda Optimization algorithm. In the optimal parameter selection, the multi-objective is considered by minimization of temperature, cooling time, pressure drop, and power consumption. In experimental analysis, the performance of the proposed approach is analyzed with the existing approaches. The proposed approach attains 98.9% accuracy, which is higher than existing approaches. [ABSTRACT FROM AUTHOR]

Modern polymer‐based technical components not only have to fulfill demanding mechanical‐structural properties but need to integrate different functions to yield hybrid systems for complex operations. Typically, neither materials nor processing technologies are fully compatible with each other. The aim of the work is to combine the advantages of seemingly incompatible manufacturing processes such as high‐volume injection molding (IM) and precision additive manufacturing to produce functional and customized hybrid materials. IM is widely used for polymer processing but stands against high investment costs for tailor‐made molds with high‐resolution features. They focus on overprinting of injection‐molded parts made of thermoplastic polyurethane (TPU) with microstructures via projection‐microstereolithography (PµSL) to generate hybrid polymer materials with spatially tailored stiffness, enabling selective reinforcement, resulting in an E modulus increase of 195% compared to mere IM‐processed TPU. With that, the hybridization of processing methods is showcased to extend the product properties of polymer materials obtained via either IM or PµSL printing that have, prospectively, a maximum degree of individualization as well as a multitude of structural and functional features at the same time. To achieve optimum interfacial adhesion, the influence of surface roughness is studied, and reinforcement effects of different overprinted microstructure types are evaluated. [ABSTRACT FROM AUTHOR]

Year by year, more and more plastic is used worldwide. A large part of post-consumer waste is still stored in landfills instead of being reused. The solution to this problem may be recycled materials (recyclates) or biodegradable materials. The method of 3D printing, regarded as a clean processing technology, can significantly contribute to addressing global plastic pollution by utilizing post-consumer recycled polymers to create new components and parts. Therefore, this study focuses on the assessment of various properties and characteristics of 3D-printed compositions based on post-consumer polypropylene (PP) and rubber crumbs, recycled from packages foils and car tires, respectively. Moreover, within this study, we compared the mechanical performance of the injection molding material with the one obtained from 3D printing. A characterization was made considering the thermal and mechanical properties as well as the "print quality" through the microscopic and tomographic analysis of subsequent print passes, the number of free spaces, and imperfections in the polymer melt. Samples obtained using the FDM and injection methods exhibited comparable melting temperatures, while the samples obtained by injection molding exhibited slightly better mechanical performance, higher hardness, and impact strength. [ABSTRACT FROM AUTHOR]

The objective of the experimental analysis was to assess the impact of the reuse of technological waste (recyclate) on the selected performance properties of the fibrous polymer composite used to produce components for the automotive industry by injection molding technology. Polyphthalamide (PPA), which belongs to a group of high-tech polymers, was chosen as the analyzed material. In accordance with the set goals, the rheological, mechanical, and structural properties of the material were evaluated using ANOVA analysis in the experimental part of the work, depending on the mass ratio of the recycled material added to the virgin material. The influence of the proportion of recycled material on the lifetime of moldings by the method of their exposure at an elevated temperature for a defined time was also assessed. During the research, it was found that at a concentration of up to 40 wt. % of recyclate, its mechanical properties do not change significantly. At a concentration of 50 wt. %, there is a rapid decrease in mechanical properties. In the long term, it can also be said that the addition of recyclate significantly affects the service life of the components. No significant changes in morphology were observed during the analysis of structural properties. [ABSTRACT FROM AUTHOR]

Nanotopographic surfaces are a powerful tool for studying and controlling cell behavior. However, the fabrication of nanotopographic master patterns using conventional photolithography is expensive, which limits the range of designs that can be explored. In this study, a method is demonstrated for the photoreshaping of large‐area patterns of nanoridges. The original master pattern is created using conventional lithography, and an azopolymer replica is prepared using soft lithography. The manipulation of the nanoridges is achieved by projecting light with specific polarizations and exposure times, resulting in controllable widening, buckling, or removal of the ridges. The reprogrammed azopolymer master patterns can then be replicated, creating reproducible new nanotopographies that can be transferred into other materials using a molding procedure. Diffraction can be used for in situ monitoring of the reprogramming during exposure. Image‐analysis methods are used to characterize buckled ridges as a function of exposure time. The response of MCF10A epithelial cells are investigated to buckled nanoridges. A substantial impact of buckling on the dynamics and location of actin polymerization, as well as on the distribution and lengths of contiguous polymerized regions is also observed. [ABSTRACT FROM AUTHOR]

Hybrid manufacturing processes integrate multiple manufacturing techniques to leverage their respective advantages and mitigate their limitations. This study combines additive manufacturing and injection molding, aiming to efficiently produce components with extensive design flexibility and functional integration. The research explores the interfacial fusion bonding of hybrid additively manufactured components under torsional loading. Specifically, it examines the impact of various surface treatments on injection molded parts and the influence of different build chamber temperatures during additive manufacturing on torsional strength. Polycarbonate components, neat, with glass or carbon fiber-reinforcement, are produced and assessed for dimensional accuracy, torsional strength, and fracture behavior. The findings emphasize the critical role of surface treatment for the injection molded components before additive manufacturing. Additionally, the study identifies the influence of chamber temperatures on both dimensional accuracy and torsional strength. Among all investigated materials, plasma-treated neat samples exhibited the best torsional strength. The torsional strength was increased by up to 87 % by actively heating the build chamber to 186 °C for neat polycarbonate. These insights aim to advance the quality and performance of hybrid additively manufactured components, broadening their application potential across diverse fields. [ABSTRACT FROM AUTHOR]

Microstructural gradients can significantly affect the properties of glass-ceramics (GCs). Such spatial variations in glass-ceramic (GC) microstructure may result from a non-uniform cooling rate when the glass-forming liquid is cast into a mold. This study investigates the material and mold size influence on the cooling process, leading to a non-uniform distribution of crystalline nuclei in the parent glass. We used a high-nucleation rate, non-stoichiometric, lithium metasilicate GC as a model. Initially, the glass-forming liquid was cooled in cylindrical molds with diameters of 7 and 14 mm, made from copper and 304 stainless steel – materials with distinct thermal diffusivities. Simulated thermography, validated by thermocouple data, showed contrasting cooling profiles across the samples. Our key findings are: i) cooling rate: faster cooling in the smaller mold resulted in a lower crystal number density and a reduced crystallized volume fraction (α v) as expected; ii) mold material: surprisingly, copper molds led to quicker glass shrinkage, which facilitated the earlier formation of air gaps with reduced heat transfer and slower cooling than steel, favoring incipient crystallization during the cooling path; iii) microstructure: samples cooled in both molds exhibited higher α v in the central and upper (mold contact-free) regions due to slower cooling compared to the mold base and edges. Therefore, this study reveals how mold material and size affect microstructural gradients in GCs, paving the way for tailoring crystallization and microstructure through strategic mold design. [ABSTRACT FROM AUTHOR]

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study was to thoroughly investigate the weather resistance of polyethylene for rotational molding under different conditions, and to comprehensively understand the changing rules of their structure and performance. The structure and properties of polyethylene rotational molding special materials were investigated under different xenon lamp aging levels by using scanning electron microscopy (SEM), infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and other characterization methods. The results show that with the increase of xenon aging time, the surface morphology of the rotational plastic undergoes significant deformation and cracking, while the intensity of the internal carbonyl characteristic peaks also shows an increasing trend. The xenon lamp aging causes a significant shortening of the oxidation induction period of the rotational plastics. However, the rotational plastics show relatively stable characteristics in terms of melting and crystallization temperatures and processing properties. In addition, the yield stress of the rotational plastics increases, while the strain at fracture, stress at break and tensile strength show a decreasing trend. The experimental data in this study provide detailed information on the weather resistance of polyethylene for rotational molding, offering references for further optimizing product performance and applications. [ABSTRACT FROM AUTHOR]

Current research on the compatibility between plastic liners utilized in Type IV high-pressure hydrogen storage containers and hydrogen remains insufficiently comprehensive. Therefore, further exploration into how the high-pressure hydrogen storage process influences the crystalline phase transition of polymers is essential to improve the applicability and safety of plastic lining materials. This study primarily investigated the preparation of polyamide 1012 (PA1012) and polyamide 11 (PA11) through rotational molding and injection molding, denoted as Roto-PA1012/Roto-PA11 and In-PA1012/In-PA11, respectively. Considering the operational parameters of the 70 MPa Type IV hydrogen storage tank, we conducted hydrogen cycling experiment using the long carbon chain polyamide (LCPA) liner materials and comprehensively analyzed the morphology, crystal structure, grain size, mechanical properties and hydrogen barrier properties of polyamide materials before and after hydrogen cycling. The results showed that after hydrogen cycling, no significant changes were observed in Roto-PA1012/Roto-PA11, while In-PA1012/In-PA11 demonstrated severe foaming. Rotational molding of LCPA maintained stable mechanical and hydrogen barrier properties throughout the hydrogen cycle, which can be attributed to the favorable thermodynamic stability of the α' form achieved during rotational molding, leading to uniform and stable crystal sizes. In conclusion, this study provides a theoretical foundation for future investigations into the molding process and material selection of high-barrier polymer liners, as well as the actual production and utilization of Type IV hydrogen storage tanks. • This research examines the effects of hydrogen circulation on the properties of long carbon chain polyamide (LCPA). • LCPA produced through rotational molding demonstrates better hydrogen compatibility compared to injection molding. • The study explores structural changes in LCPA during hydrogen absorption and desorption. [ABSTRACT FROM AUTHOR]

Massively using conventional plastics has led to significant environmental issues, including harm to ecosystems, wildlife, and human health, contributions to greenhouse gas emissions, and resource depletion through their extraction and production. Thus, there is an urgent imperative to seek sustainable alternatives like bio-composites. This research established the viability of banana peels and cassava starch for eco-friendly bio-composite sheets, offering insights into their properties and performance The bio-composite materials, composed of banana peels, cassava starch, banana stem fiber, glycerol, and acetic acid, were prepared in different weight-based proportions. The preparation process involved cleaning, drying, blending, and molding the materials to produce consistent bio-composite samples. The properties and performance of the composite samples were assessed for water absorption, moisture content, and tensile strength. Notably, the combination of banana peels and cassava in a 1:2 ratio, along with banana stem fiber, demonstrated favorable attributes, including reduced water absorption (ranging from 6.42 to 30.91%), desirable moisture content (ranging from 8.06 to 11.27%), and increased tensile strength (ranging from 5.345 to 11.892 MPa). These findings confirm the viability of using banana peels and cassava starch in producing bio-composite sheets, offering a sustainable alternative to conventional plastics. This study contributes to the field of sustainable materials by providing insights into the properties and performance of bio-composites, thereby supporting the development of ecofriendly bio-composite sheets. [ABSTRACT FROM AUTHOR]

We investigated interactions between Ti6Al4V alloys and strontium zirconate (SrZrO3) ceramic to assess its potential as a refractory mold material in investment casting. We developed a robust yet simple procedure to examine both the liquid–solid and solid–solid interactions using pellets in drop casting and diffusion couple methods. Reaction layers were characterized using optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD). The results were compared to alumina (Al2O3) which is still a common refractory ceramic for molds in investment casting. Our findings indicate that Ti6Al4V surfaces in contact with SrZrO3 had no apparent changes in surface chemistry nor microstructure. On the other hand, Ti6Al4V surfaces in contact with Al2O3 developed γ-TiAl and α2-Ti3Al intermetallics with thicknesses of ~ 100 μm in diffusion couples and ~ 10 μm in drop-casting experiments. Nanoindentation results showed that the surface of Ti6Al4V in contact with Al2O3 was significantly harder compared to SrZrO3, confirming our conclusion. Given the time and costs associated with mechanical and chemical removal of reaction layers on Ti6Al4V castings, SrZrO3 can be a better choice for a mold material in the investment casting of titanium alloys. [ABSTRACT FROM AUTHOR]

Inorganic binder used in casting process has the advantages of low odor, labor-friendly conditions, and relatively low cost, which is one of the main development directions for casting molding materials in the future. However, compared to organic binders (such as resin binders), inorganic binders exhibit lower bonding strength and are more sensitive to environmental humidity. This sensitivity poses challenges, particularly in the reclamation of used sand, thus limiting their broader application. In this paper, the research and application status of inorganic binders (mainly silicate inorganic binders) and their curing methods are summarized. In addition, the research and application of phosphate inorganic binders and 3D printing inorganic binders that are being developed are introduced. Meanwhile, a detailed comparative analysis is conducted on the challenging issue of "reclamation for used sand" in the application of inorganic binders. Finally, the development direction of inorganic binders is clarified. [ABSTRACT FROM AUTHOR]

To improve our previous simulation-based training module by using sustainable material to mold an anatomically accurate terrain and reproducing major vascular injuries encountered during robot-assisted nephrectomy. The simulator was built with a pump, gauge, and valve linked via silicone tubing. Artificial blood was made from cornstarch, water, and red dye, and pumped through 3D-Med artificial vessels with the dimensions of an average renal artery. Silicone was used to emulate the pliability of organic tissue and mold an anatomically accurate terrain. Eight urologic residents participated in the pilot simulation. We employed validated assessment tools including Non-Technical Skills for Surgeons and Objective Structured Assessment of Technical Skills forms to guide debrief sessions moderated by an expert physician after individual performance evaluations. The apparatus demonstrated high reproducibility across all simulation scenarios, enhancing resident problem-solving skills. Residents' pre-simulation surveys revealed significant concern regarding their acute hemorrhage management. Residents' post-simulation survey demonstrated average realism scores increased from 4.375 to 4.75. Residents also felt the simulator enhanced learning, offering valuable practice and knowledge applicable to their surgical specialty. The management of acute hemorrhage during robot-assisted surgery remains a space for additional surgical education and training. Our simulation successfully provided a reliable, reproducible training for residents to practice their technical and non-technical skills in managing acute hemorrhage. [ABSTRACT FROM AUTHOR]

Copyright of FME Transactions is the property of University of Belgrade, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The transition to a sustainable future requires the use of waste‐free technologies for production. Potentially, additive technologies can be a promising approach for accessing circular economy due to the precise amount of feeding materials and the absence of molds. However, the initial feeding materials for additive approaches are often based on non–renewable hydrocarbon sources. This work focused on the use of polymers derived from terpene alcohols to develop a filament suitable for 3D printing. Initially, the vinylation of menthol using calcium carbide was optimized and scaled up, then a series of terpenyl–based vinyl ethers were obtained under optimal conditions. The cationic polymerization of vinyl ethers was also scaled up and resulted in 99 % yield of the polymers, which was subsequently subjected to hot extrusion. The initial terpenol was used as an additive to increase polymer flexibility. The addition of menthol (30 wt %) to polyvinyl menthol led to the suitable filament. Using the filament, a series of objects were 3D printed at 125 °C. The material demonstrated good sinterability and adhesion to glass and shrinkage comparable to that of commercial 3D printing filaments. Furthermore, the polymers obtained were used as additives to enhance the adhesion of commercially available filaments. [ABSTRACT FROM AUTHOR]

To investigate the flexural strength (FS), elastic modulus (E), Martens hardness (HM), water sorption (w sp), water solubility (w sl) and degree of conversion (DC) of 3D-printed, milled and injection molded splint materials. Specimens (N = 1140) were fabricated from five 3D-printed (GR-22 flex, GR-10 guide, ProArt Print Splint clear, V-Print Splint, V-Print Splint comfort), five milled (BioniCut, EldyPlus, ProArt CAD Splint clear, Temp Premium Flexible, Thermeo) and two injection molded (PalaXPress clear, Pro Base Cold) materials. FS, E, HM, w sp , w sl and DC were tested initially (24 h, 37 °C, H 2 O), after water storage (90 d, 37 °C, H 2 O) as well as after thermal cycling (5000 thermal cycles, 5/55 °C). Data were analyzed with Kolmogorov-Smirnov, Kruskal- Wallis, Mann-Whitney U test and Spearman's correlation (p < 0.05). Initially, the mean flexural strength values ranged from 1.9 to 90.7 MPa for printed, 3.8 to 107 MPa for milled and 99.7 to 102 MPa for injection molded materials. The initial mean elastic modulus values were 0.0 to 2.4 GPa for printed, 0.1 to 2.7 GPa for milled and 2.8 GPa for injection molded materials. The initial mean Martens hardness values were 14.5 to 126 N/mm2 for printed, 50.2 to 171 N/mm2 for milled and 143 to 151 N/mm2 for injection molded materials. Initially, the mean water sorption values ranged from 23.1 to 41.2 μg/mm3 for printed, 4.5 to 23.5 μg/mm3 for milled and from 22.5 to 23.3 μg/ mm3 for injection molded materials. The initial mean water solubility values ranged from 2.2 to 7.1 μg/mm3 for printed, 0.0 to 0.5 μg/mm3 for milled and 0.1 to 0.3 μg/mm3 for injection molded materials. After water storage and thermal cycling most of the values decreased and some increased. The mean DC values ranged initially from 72.3 to 94.5 %, after water storage from 74.2 to 96.8 % and after thermal cycling from 75.6 to 95.4 % for the printed materials. The mechanical and physical properties of printed, milled and injection molded materials for occlusal devices vary and are influenced by aging processes. For clinical applications, materials need to be chosen according to the specific indications. [ABSTRACT FROM AUTHOR]

PC/ABS blends are commonly used for the production of automotive components due to their thermal and mechanical properties. However, changes in process conditions can have a significant impact on their properties and microstructure. Therefore, determining the optimal parameters for the injection molding (IM) process is critical for effective control of the mechanical properties and quality of the injected parts. In this study, the Taguchi method is applied to investigate the relationship between the tensile stress (σ), Young's modulus (E) and IM process of PC/ABS blends. The effects of different molding parameters such as material temperature, injection pressure, holding time and mold temperature were investigated. The optimal injection parameters to achieve higher tensile stress (σ) and Young's modulus (E) were predicted by studying the signal-to-noise ratio (S/N). Thus, the objectives of the Taguchi approach for the IM process are to determine the optimal combination of process parameters and to reduce the quality variations between only a few trials. Two optimal parameter combinations were found yielding very significant mechanical properties (σ, E) of the injected parts. These optimum combinations consist of material temperature of 260 °C, injection pressure ranging between 40 and 50 bar, holding time of 8 s and mold temperature of 60 °C. Experimental results prove that injection pressure and material temperature have the most significant impact on the mechanical properties and the microstructure of PC/ABS blends. These findings may have interesting applications in the automotive industry. [ABSTRACT FROM AUTHOR]

An optimal portable microfluidic device should ensure least number of accessories for versatile field application. Typically, in such a device fabricated with polydimethylsiloxane (PDMS), the transport of fluid is enabled through a nonconventional pumping mechanism. This pumping system has been demonstrated to utilize the relatively high air permeability of polydimethyl siloxane (PDMS) to transport small volume fluid. In the recent past, microporous PDMS has replaced PDMS in this capacity. Microporous PDMS is typically fabricated through a series of steps where a sacrificial template is used to infiltrate the polymer. This template is removed after the polymer undergoes curing. This method has consistently produced a spongy structure that is nonrigid, sticky, and moist rendering it unwieldy. In this work, we present a novel concept of using camphor (Cinnamomum camphora) as a template to fabricate a dry polymeric sponge. The proposed sponge is molded on a sublimable material, camphor to avoid the additional step of template dissolution. The sponge is demonstrated to be stiff yet flexible rendering it convenient to be compacted into a confined space. Additionally, the sponge is dry and nonsticky as compared to structures that have been generated through sugar leaching. [ABSTRACT FROM AUTHOR]

A lightweight water-soluble core mold material for hollow shell composites was prepared by hot drying process with polyvinylpyrrolidone (PVP) aqueous solution as the adhesive and hollow glass microspheres as the matrix material. The effects of the content of adhesive and different treatment methods on the flexural strength, compressive strength and dissolution rate of the core mold were studied, and the microstructure of the core mold material was observed by scanning electron microscope. The results show that adhesive dosage of 40%, the flexural strength and compressive strength could reach up to 3.346 MPa and 3.499 MPa, with a water solubilization rate of 0.238 g/s. After the coupling agent treatment and high temperature treatment, the core mold strength and dissolution rate are improved, and the modification effect is good; small filler sizes can effectively fill the gap formed by matrix materials accumulation, improve the mechanical strength and affect the water solubility rate. The properties of water-soluble core can meet the requirements of resin transfer molding (RTM) and vacuum bag molding, which provides a solution for the integrated molding of profiled hollow profiles. [ABSTRACT FROM AUTHOR]

This paper presents the design, construction, and implementation of a soft robotic system comprising a continuum manipulator arm equipped with a compliant gripper. Three main objectives were pursued: (1) developing a soft silicone gripper as an alternative to expensive and rigid steel grippers, enabling safe and precise handling of delicate or irregular objects such as fruits, glassware, and irregular shapes; (2) fabricating a continuum manipulator arm with robotic joints inspired by vertebrae, allowing for smooth, non-linear motion and more excellent maneuverability compared to traditional rigid arms, enabling access to hard-to-reach areas; and (3) integrating the compliant gripper with the continuum manipulator and implementing a control system for the soft gripper and remote bending arm using a microcontroller. The soft gripper, manipulator arm vertebrae, and other components were fabricated using 3D printing with PLA material for the molds. The gripper construct used hyperelastic silicone (Ecoflex 00.30). The continuum manipulator achieved a higher degree of freedom and mobility, while simulations and experiments validated the design's effectiveness. The comparison shows that the close agreements differ by only 2.5%. In practical experiments involving lifting objects, the gripper was able to carry items with a greater mass. The proposed soft, integrated robotic system outperformed traditional rigid approaches, offering safe and flexible handling capabilities in unstructured environments. The nature-inspired design enabled a compliant grip and enhanced maneuverability, making it suitable for various applications requiring dexterous manipulation of delicate or irregularly shaped objects. [ABSTRACT FROM AUTHOR]

The rapid tooling of mold inserts for injection molding allows for very fast product development, as well as a highly customized design. For this, a combination of rapid prototyping methods with suitable polymer materials, like the high-performance thermoplastic polymer polyetheretherketone (PEEK), should be applied. As a drawback, a huge processing temperature beyond 400 °C is necessary for material extrusion (MEX)-based 3D printing; here, Fused Filament Fabrication (FFF) requires a more sophisticated printing parameter investigation. In this work, suitable MEX printing strategies, covering printing parameters like printing temperature and speed, for the realization of two different mold insert surface geometries were evaluated, and the resulting print quality was inspected. As a proof of concept, ceramic injection molding was used for replication. Under consideration of the two different test structures, the ceramic feedstock could be replicated successfully and to an acceptable quality without significant mold insert deterioration. [ABSTRACT FROM AUTHOR]

Copyright of West China Journal of Stomatology is the property of Sichuan University, West China College of Stomatology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Key components of the existing external meshing dorsal spine plungertype molding machine were modeled in three dimensions, and the fatigue life analysis of the molding machine spindle was carried out by using Ansys software. Due to the nonlinear mechanical behavior of the material ring mold, and pressure roller in the granulation process, there are a lot of contacts and collisions. Using the linear mechanics model is difficult to analyze. To achieve more accurate and realistic results, an Edem-Ansys joint coupled simulation was carried out for the pressure roller and ring mold engagement process. The results showed that the stress concentration point and fatigue weak region of the spindle occurred at the shaft cross-section, where the stress value should be less than 0.75 F. The maximum stresses and strains in the engagement process of the pressure roller and the ring die body occurred at the engagement point. The maximum values of deformation, stress, and strain were 0.039 mm, 412 MPa, and 0.002 mm/mm, respectively, which are all within the reasonable range and meet the design requirements. [ABSTRACT FROM AUTHOR]

The evaluation of mold properties is crucial in the foundry industry to ensure efficient and high-quality casting production. This study focuses on the assessment of mold properties using silica sand, copper slag, and their mixture as molding materials in the sodium silicate, CO2 (carbon dioxide) chemical binder process. The properties investigated include mold hardness, permeability, and compressive strength. The aim is to evaluate their suitability and performance in comparison with traditional molding materials. The results indicate that a mixture of 6% sodium silicate and 15 sec of CO2 gas passing is highly effective in achieving optimum mold properties for both slag and sand molds. These properties remained stable even after prolonged exposure to different weathering conditions, highlighting the durability of the molds. Furthermore, the study revealed that the combination of sand and slag yields mold properties that lie between those of the pure ingredients. Specifically, a mixture comprising 80% sand and 20% slag exhibited the most desirable properties. Additionally, investigations were conducted using a 20% sand and 80% slag mixture, which demonstrated improvements in mold properties. In terms of material substitution, the evaluation of mold properties using the CO2 process showed that copper slag displayed similar characteristics to sand. This finding suggests that copper slag can serve as a suitable alternative to partially or fully replace silica sand in mold-making applications. [ABSTRACT FROM AUTHOR]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, a novel internal heat absorption technology using inorganic material rods is employed during the solidification process of steel ingots, aiming to control their solidification and improve the quality of the final product. The study investigates the effect of the insertion depth of inorganic materials on the solidification microstructure and macrosegregation of 2.5-ton 42CrMo ingots. The mechanical properties of samples from the product are also tested. A numerical simulation model for casting 2.5-ton ingots is established and implemented in Ansys Fluent fluid simulation software, with inorganic material rods set at different preset depths. The simulation explores the physical processes of the melting and floating of inorganic materials in molten steel, as well as their effects on the temperature and flow fields of the material. The results show that deeper insertion of inorganic materials (200 mm from the hot top) reduces the tendency for macrosegregation compared to that at the insertion depth of 100 mm. Specifically, the positive segregation area decreases by 10.35%, while the negative segregation area decreases by 15.32%. Moreover, deeper insertion results in a significant refinement of the solidification microstructure, ultimately enhancing the mechanical properties of the products machined from the ingots (i.e., the yield strength increased by 4.7%). The numerical simulation results indicate that as the placement depth of inorganic materials in the ingot mold increases, the cooling effect becomes more significant, the flow area of molten steel initiated by the inorganic materials expands, and the linear velocity of the double-circle flow increases. This further explains why the solidification quality of the ingots improves with the increasing placement depth of inorganic materials. [ABSTRACT FROM AUTHOR]

This document is a discussion of a research paper titled "A Critical Assessment of the Effect of Initial Fabric on Key Small-Strain Design Parameters of Slurry-Deposited Silts and Sands." The authors of the discussion raise several queries and observations related to the proposed slurry deposition naming convention, measurement of the critical state line, end restraint, triaxial specimen uniformity, and the accessible in situ states and full-scale behavior of silts. They question the authors' claims and suggest alternative perspectives and evidence. The discussion provides valuable insights and raises important considerations for further research in the field of geotechnical engineering. [Extracted from the article]

This article focuses on polyamide materials T1 and B1, and uses two types of fungi to conduct anti mold tests on them. It conducts in-depth exploration and research on the failure mechanism during the co cultivation process!* of fungi and polyamide. Through infrared spectroscopy analysis;, it was; found that mold growth can absorb oxygen from the outside, which can cause the methylene on the polyamide molecular chain to break and react with it to form carbonyl groups, causing changes in the internal structure of the molecule. Through UV spectroscopy and nuclear magnetic resonance analysis, it can be seen that due to the presence of highly reactive methylene structures on the internal molecular chains of polyamide, the color of polyamide and mold will change during the co cultivation process. It will react with the outside world to generate methylene free radicals, further react with oxygen to generate hydrogen peroxide, and then isomerize to generate carbonyl groups. The carbonyl groups then combine with other active groups to produce carbonyl imines. As a result, the conjugated chains on the polyamide molecular chains will increase, and the maximum absorption wavelength will be seen in the visible light region, which is macroscopically manifested as the color change of the polyamide material. Thermogravimetric analysis shows that fungi can obtain nutrients from the surface of polyamide for reproduction, and the surface structure will undergo significant damage and changes. Mechanical performance tests have shown that mold can cause a decrease in the tensile, bending, and impact properties of polyamide materials, and the two types of mold can cause different degrees of attenuation. [ABSTRACT FROM AUTHOR]

Sheet Molding Compound (SMC) materials are extensively utilized as high-voltage insulation materials in electrical equipment. SMC materials are prone to aging after long-term operation. Conducting non-destructive testing to assess their electrical and physicochemical properties is crucial for the safe operation of electrical equipment. This study identifies the optimal equipment parameters for testing SMC materials using Laser-Induced Breakdown Spectroscopy (LIBS) technology through experimental investigation and also explores the ablation characteristics of SMC under various laser parameters. The results indicate a significant positive correlation between the ablation depth and laser pulse number, while there is no correlation with single laser pulse energy. However, the ablation area demonstrates a strong positive correlation with both single laser pulse energy and laser pulse number. Additionally, LIBS spectral analysis provides elemental results comparable to Energy Dispersive Spectroscopy (EDS), facilitating the examination of variations in Na, Ti, Fe, Mg, Ca, and C elemental contents with depth. Moreover, an enhanced iterative Boltzmann plot method is suggested for calculating the plasma temperature using 21 Fe I spectral lines and the electron density using the Fe II 422.608 nm line. The variations of these plasma parameters with laser pulse number are documented, and the results show consistent trends, confirming that the laser-induced SMC plasma adheres to local thermodynamic equilibrium. [ABSTRACT FROM AUTHOR]

Although various additive manufacturing techniques are used intensively to mold materials for solid oxide fuel cell (SOFC) applications, 3D printing has not been applied to obtain sealants which are crucial components for SOFC stacking. It is essential to develop different methods for molding sealing products based on glasses and glass-ceramics which are the most promising materials for SOFC stacking. This study reveals the potential of fused deposition modeling (FDM) for the production of complex shape objects for the sealing of tubular SOFC in the example of the composition based on thermoplastic, thermoplastic elastomer, oil, and a filler (glass sealant). The highest filler content in the mixture is 63 wt %. Two aluminosilicate sealants of different compositions are used as the filler and the printed products are successfully applied for tubular supporting anode|sealant|steel joints. • FDM is successfully used to obtain products for tubular SOFC sealing. • Bubbles in the sealant volume do not violate the sealing. • Tubular supporting anode|sealant|steel joints are prepared using printed products. [ABSTRACT FROM AUTHOR]

Without using fossil resources such as petroleum and coal, which are likely to be depleted and have a large load on the environment, we studied the improvement of the performance of phenolic resin using lignin‐based natural material, which is a non‐fossil resource that is less likely to cause environmental problems. Using modified lignin with polyethylene glycol, the modified lignin phenolic novolac resin was synthesized, and the properties of the phenolic resin molding material and molded article containing the modified lignin were evaluated. As a result, it was found that the phenolic resin into which the modified lignin was introduced not only has excellent moldability, but also excellent heat resistance, mechanical strength, and electrical insulation, and can achieve both heat resistance and flexibility. [ABSTRACT FROM AUTHOR]

Injection molding is the most common method to mass‐produce plastic parts. The high cost and long lead time of traditional injection molding steel molds make 3D‐printed plastic molds a potential substitute for limited production runs and prototype parts. However, results suggest that for some materials, utilizing plastic molds (compared to metal molds) could decrease the mechanical properties of parts, especially the ductility. In order to better understand the issues with utilizing plastic molds, in this work, we use a design of experiments to investigate how the processing parameter changes affect mechanical properties by comparing a semi‐crystalline polypropylene and an amorphous polystyrene material in a metal mold for better control of the controllable variables. Results show that ductility is the most sensitive property to processing conditions, especially for polypropylene. Our analysis shows that the controllable variable that affects ductility the most is mold temperature, then packing pressure, and injection time. Highlights: 3D‐printed plastic molds is a potential substitute for limited production runs.Effects of processing parameters are analyzed through the design of experiments.Ductility is the most sensitive property to processing conditions for the material studied.Mold temperature is the most significant variable for ductility. [ABSTRACT FROM AUTHOR]

In this work, a new plastic-intensive medium-pressure plate (MPP), which is part of a fuel-cell system, has been developed together with a steel plate meeting all mechanical and chemical requirements. This newly developed MPP had to achieve the objective of saving weight and package space. The use of compression molding as a manufacturing technique facilitated the use of glass mat thermoplastics (GMT) which has higher E-modules and strength compared to most of the injection molded materials. A steel plate was placed as an insert to help achieve the stiffness requirements. For the development, the existing MPP was benchmarked for its structural capabilities and its underlying functional features. Four different FRP materials were investigated in terms of their chemical and mechanical properties. PP-GMT material, which has both high mechanical performance and resistance against chemicals in the fuel cell fluid, had been chosen. Using the properties of the chosen PP-GMT material, topology optimization was carried out based on the quasi-static load case and manufacturing constraints, which gave a load-conforming rib structure. The obtained rib structure was utilized to develop the final MPP with adherence to the functional requirements of MPP. The developed plastic-intensive MPP exhibits a 3-in-1 component feature with a 55% reduction in package space and an 8% weight reduction. The MPP was virtually analyzed for its mechanical strength and compared with the existing benchmark values. Finally, a press tool was conceptualized and manufactured to fabricate the new plastic-intensive MPP, which was tested in a rig and validated in the FE model. [ABSTRACT FROM AUTHOR]

Conventional cooling channels used in die casting molds exhibit significant drawbacks, resulting in extended cooling times for cast parts. Issues such as the formation of dirt, limescale, and corrosion substantially diminish the thermal efficiency of these channels, leading to challenges in achieving uniform cooling and potential quality issues. In response to these challenges, this study proposes Topology Optimization as a novel approach. It involves designing cooling structures through Topology Optimization to replace traditional cooling channels, incorporating both Discrete and Gaussian boundary conditions to optimize thermal efficiency. Additionally, Structural Topology Optimization is employed to ensure structural integrity, preventing deformation or yielding under high loads during the die casting process. Numerical analysis revealed superior thermal performance compared to conventional channels, particularly when subjected to Discrete and Gaussian boundary conditions. Furthermore, the application of the latter establishes conformal cooling and minimizes temperature gradients in the casting, reducing casting defects such as shrinkage porosity. These findings highlight the efficacy of Topology Optimization in addressing the challenges of traditional cooling methods, with wide-ranging implications for manufacturing processes utilizing permanent molds for shaping materials. [ABSTRACT FROM AUTHOR]

The use of processed limestone sludge as a crosslinking agent for films based on Na–alginate and ɩ-carrageenan/Na-alginate blends was studied. Sorbitol was tested as a plasticizer. The produced gel formulations included alginate/sorbitol and carrageenan/alginate/sorbitol mixtures, with tested sorbitol concentrations of 0.0, 0.5 and 1.0 wt%. The limestone sludge waste obtained from the processing of quarried limestone was converted into an aqueous solution of Ca2+ by dissolution with mineral acid. This solution was then diluted in water and used to induce gel crosslinking. The necessity of using sorbitol as a component of the crosslinking solution was also assessed. The resulting films were characterized regarding their dimensional stability, microstructure, chemical structure, mechanical performance and antifungal properties. Alginate/sorbitol films displayed poor dimensional stability and were deemed not viable. Carrageenan/alginate/sorbitol films exhibited higher dimensional stability and smooth and flat surfaces, especially in compositions with 0.5 wt% sorbitol. However, an increasing amount of plasticizer appears to result in severe surface cracking, the development of a segregation phenomenon affecting carrageenan and an overall decrease in films' mechanical resistance. Although further studies regarding film composition—including plasticizer fraction, film optimal thickness and film/mold material interaction—are mandatory, the attained results show the potential of the reported ɩ-carrageenan/alginate/sorbitol films to be used towards the development of viable films derived from algal polysaccharides. [ABSTRACT FROM AUTHOR]

The article describes the simulation of the casting of the low-melting material stearin into a mold, which serves as a real simulation basis for monitoring the displacement during the solidification of steel ingots. The physical properties and occurrence of shrinkage are comparable for both liquid stearin and molten steel. In this way, it is possible to easily monitor the solidification of ingots after casting, while the entire simulation takes place at low temperatures, which is experimentally simpler and more practical than trial casting steel at high temperatures. The process is convenient, simple, fast and cheap. The essence is therefore the application of a new perspective on the mentioned process and its transfer into foundry practice. The temperature drop in the entire volume of the sample was monitored from filling the mold to cooling to ambient temperature and the formation of shrinkage, which was monitored and evaluated in the internal body of the ingot. The tests confirmed the suitability of selected material for this method of experimental work because they were able to capture the real behavior of the cast steel in the mold. The method proves to be suitable for industrial applications where similar multidimensional castings are produced. [ABSTRACT FROM AUTHOR]

The continuous evolution of composite materials has sparked increasing interest in more precise and reproducible testing methods. The use of Computer Numerical Control (CNC) to create molds for composite material tensile specimens represents a significant advancement in this field. This innovative approach ensures enhanced precision, uniformity in sample fabrication, and efficient adaptation to the specific requirements of composite materials. This article focuses on the CNC mold creation process for composite material tensile specimens, highlighting its advantages and advancements in the field of material testing. [ABSTRACT FROM AUTHOR]

Double‐injection molding involves the use of two injection units, A and B, which can combine two different plastics into one part in a single injection molding process. Double‐injection molding can promote the recycling of plastic waste as well as improve the performance and dull appearance of plastic products made from recycled materials. However, the warpage of parts is a significant challenge in double‐injection molding. Warpage is significantly affected by the properties of the recycled material and injection molding process. In this study, the relationship between the warpage of double‐injection‐molded parts using raw and recycled materials was studied through uniform design experiments. To investigate the processes and warpage, the material was recycled several times, and its properties were tested. A regression model was established to describe the quantitative relationship between the important parameters and warpage. The number‐average molecular weight and weight‐average molecular weight exhibited the largest decrease after the first recycling cycle with a 21.11% and 41.11% decrease, respectively. The melting temperature decreased from 164.61 to 159.35°C, and the crystallinity did not change significantly. The processing parameters varied with the change in the properties of PP recycled materials, with the melt temperature decreased from 225 to 210°C. In addition, the number of recycling cycles and holding time for B were the most important factors influencing the warpage of double‐injection‐molded parts, followed by holding time for A and melt temperature for A. Warpage can be reduced by increasing holding times B and A. The experimental results provide important data for reducing the warpage of double‐injection‐molded parts with recycled materials. Highlights: Double‐injection‐molded parts containing recycled materials were prepared.Recycling enhanced the filling capacity of polypropylene.The regression model of warpage with variables was established.Warpage can be improved by adjusting processes and materials. [ABSTRACT FROM AUTHOR]