Abstract Although the formation of zeolites in geopolymers have been mentioned in many works, a particular interest in geopolymer-zeolite composites started to increase very recently. Such hybrid materials connect the advantageous properties of both constituents: geopolymer serves as a strong and durable support for zeolites, when zeolites provide high surface area, porosity and adsorption capacity. The composites can be therefore used as bulk-type adsorbents as well as membranes in separation and pervaporation processes. The possibility of the utilization of industrial wastes for their production is also a sustainability benefit. This review article highlights advances in the field of geopolymer-zeolite composites manufacturing and applications. The resistance of zeolites in geopolymer matrices, methods of their detection and effect of their presence on the properties of hybrid materials are discussed as well.
Lithography serves as a fundamental process in the realms of microfabrication and nanotechnology, facilitating the transfer of intricate patterns onto a substrate, typically in the form of a wafer or a flat surface. Grayscale lithography (GSL) is highly valued in precision manufacturing and research endeavors because of its unique capacity to create intricate and customizable patterns with varying depths and intensities. Unlike traditional binary lithography, which produces discrete on/off features, GSL offers a spectrum of exposure levels. This enables the production of complex microstructures, diffractive optical elements, 3D micro-optics, and other nanoscale designs with smooth gradients and intricate surface profiles. GSL plays a crucial role in sectors such as microelectronics, micro-optics, MEMS/NEMS manufacturing, and photonics, where precise control over feature depth, shape, and intensity is critical for achieving advanced functionality. Its versatility and capacity to generate tailored structures make GSL an indispensable tool in various cutting-edge applications. This review will delve into several lithographic techniques, with a particular emphasis on masked and maskless GSL methods. As these technologies continue to evolve, the future of 3D micro- and nanostructure manufacturing will undoubtedly assume even greater significance in various applications.
ZHANG Jiarui, MOU Yuankun, GUO Kailun, WANG Chenglong, TIAN Wenxi, QIU Suizheng, SU Guanghui
High-temperature heat pipes rely on the capillary force provided by the wick to enable the reflux of condensed working fluid, where the mass transfer capacity of the wick directly affects the heat transfer performance of the heat pipe. However, in the current design and manufacturing of high-temperature heat pipes, due to the generally high hardness of metal wire meshes, interlayer gaps exist between mesh layers after being rolled into wicks, and current design calculations do not consider the influence of these interlayer gaps on wick performance. Therefore, wire mesh wicks are often selected and manufactured based on previous production experience, making it impossible to exclude wire mesh selection as a factor when the heat pipe performance is poor. This paper focused on wire mesh wicks for high-temperature heat pipes, conducting experimental research on permeability performance and modifying existing mathematical models by considering interlayer gaps, resulting in a mathematical model that better fits experimental results. The research results show that the porosity of different types of wire mesh wicks under the same process conditions ranges from 0.433 to 0.879, the porosity of single-mesh-number wicks should decrease monotonically with increasing mesh number, but due to the poor liquid absorption capacity caused by the large pores of 50-mesh wicks, their porosity is anomalously small. The 600-mesh wick has the highest permeability at 2.070×10−9 m2, and there is a positive correlation between porosity and the effective capillary radius of the wick. The effective capillary radius first decreases and then increases with increasing mesh number, while permeability shows a trend of decreasing-increasing-decreasing with increasing mesh number. Existing mathematical models cannot correctly characterize the microscopic parameters of wire mesh wicks, with the permeability results for 800-mesh wicks differing by two orders of magnitude, and even the smallest error for 50-mesh wire mesh reaching 278.1%. Moreover, the larger the mesh number, the greater the error between experimental and theoretical values. Under electron microscope observation, a wire mesh wick model considering gap effects was proposed and compared with experimental results. The theoretical permeability calculations for wire mesh wicks with gaps better match the experimental values, with relative errors of 33.63% and 24.68% for 50-mesh and 400-mesh wire meshes, respectively, while the trend of permeability changes with mesh number also aligns well with experimental results. Overall, the error is reduced by 1-2 orders of magnitude compared to the original mathematical model. The findings of this study hold significant implications for wick parameter selection and design optimization of high-temperature heat pipes.
Aronal Arief Putra, Elfi Rahmi, Vitania Yulia
et al.
A community engagement initiative was conducted with Bondo Bakery, a local homemade bakery producer in Padang. The goal was to assess the bakery's current conditions and explore ways to enhance its business capacity. Activities included visits to the processing room, focus group discussions, product development for premium variants, training for home industry food production, and technical support for MSME business permit registration. These efforts aimed to establish foundational steps for identifying necessary improvements related to the processing room, expanding the range of bakery products to include options enriched with animal products, mapping the competitive landscape to inform strategic planning, and enhancing knowledge of food production practices—including good manufacturing practices (GMP), food quality and safety, and relevant regulations in the food sector. Furthermore, assistance in acquiring a business permit was provided. In conclusion, these collaborative actions have positively contributed to strengthening the business capacity of the enterprise.
Abstract Against the backdrop of increasing uncertainty in the global supply chain and simultaneous rise in procurement costs and delivery risks for enterprises, the traditional material procurement model is facing severe challenges due to information silos between departments, deviation in demand forecasting, and dynamic changes in supplier relationships; especially in the semiconductor manufacturing industry, high capital investment, long lead times, and high demand volatility can lead to significant capacity losses due to procurement decision-making errors. Therefore, this article constructs an enterprise material procurement management optimization framework based on a global linkage mechanism, aiming to use intelligent means to connect procurement, production, and warehousing data, and achieve multiple goals of cost reduction, quality assurance, and stable supply. The framework includes three technological innovations: ① integrating a Bayesian convolutional neural network and multi-head attention mechanism, using device image features and sensor timing data to predict material remaining life, and reducing the root mean square error of semiconductor key consumables demand prediction to 2.12 × 10⁶ (23.7% lower than LSTM), p < 0.01); ② designing a multi-objective optimization engine that combines the NSGA-II algorithm with a supplier maturity evaluation system that includes six indicators such as timely delivery rate and defect feedback rate to achieve Pareto equilibrium of procurement cost, quality defect rate, and delivery delay rate; the experiment shows that the total procurement cost is reduced by 17.4%, and the supplier complaint rate is reduced to 3.2%; ③ proposing a Global Linkage Rule Set (GLR), which coordinates the data flow of production, warehousing, and procurement through dynamic weights. In the empirical study of semiconductor manufacturing enterprises, it reduces emergency procurement frequency by 42% and increases inventory turnover by 29%. This study provides a reusable methodological framework and validated technical cases for the intelligent transformation of supply chains in capital-intensive industries such as semiconductor manufacturing.
Co-Cr-Mo alloys are in high demand as materials for medical implants. However, hot processing of these alloys is quite difficult due to the need to maintain narrow temperature range of deformation to achieve the required mechanical properties and structure of the products. The features of formation of structure, phase composition and mechanical properties of Co-Cr-Mo alloy at the main stages of thermomechanical treatment were considered in this study. The results demonstrated a significant enhancement in the strength characteristics of the alloy during processing in both forging and radial shear rolling (RSR). At the same time, radial shear rolling processing simultaneously increased the strength and ductility of the alloy. According to the XRD analysis data, the phase composition changes from single-phase structure (FCC-phase) after forging to a mixture of FCC-phase and HCP-phase after RSR during processing. The structure gradient characteristic of RSR decreased as the total elongation ratio increased, maintaining a tendency towards a finer-grained structure near the surface of the bars and a coarser one in the center. This tendency was reflected in the average grain size and the level of mechanical properties. Combined thermomechanical treatment, including the RSR process, made it possible to achieve a unique formation of microstructure and phase composition in the Co-Cr-Mo alloy, ensuring high strength while maintaining ductility.
We introduce a notion of capacity for high dimensional critical percolation by showing that for any finite set $A$, the suitably rescaled probability that the cluster of $z$ intersects $A$ converges as $\|z\|\to\infty$. This can be viewed as a generalisation of the asymptotic of the two point function and we call the limit the p-capacity of $A$. We next show that the probability that the Incipient Infinite Cluster of $z$ intersects the set $A$ appropriately normalised is also of order the p-capacity of $A$ as $\|z\|\to\infty$. We conjecture that the p-capacity is of the same order as the $(d-4)$-Bessel-Riesz capacity and in support of this we estimate the p-capacity of balls. As a byproduct of our techniques we give a simpler proof of the one-arm exponent of Kozma and Nachmias for dimensions 8 and higher and as long as the two point function asymptotic holds. Our proofs make use of a new large deviations bound on the pioneers, that is the number of points on the boundary of a box which are part of the cluster of the origin restricted to this box.
Completely positive operators are fundamental objects in quantum information theory and the capacity of such operators plays a pivotal role in the operator scaling algorithm. Using this algorithm, Garg--Gurvits--Oliveira--Wigderson recently established a certain quantitative continuity result for the capacity map at rational points. We show by different means that operator capacity possesses significantly greater regularity. Our argument gives local Hölder continuity at all points and rests on a result of Bennett--Bez--Buschenhenke--Cowling--Flock on weighted sums of exponential functions.
Mazhar Hussain, Hafida Zmamou, Antony Provost
et al.
The production of construction and demolition waste (CDW) in urban areas is growing rapidly. While the storage and disposal of CDW waste is costly, its recovery can help to conserve natural resources. This study investigates the characteristics of recycled sand obtained from the processing of CDW waste and the possibility of its reuse for pedestrian pathways. Physico-chemical and mineralogical characteristics of the recycled sand were investigated for its reuse. The percentage of fine particles in sand (below 0.63 μm) is 2.8%. The grain size of sand fulfills the particle size requirement of French standards. The methylene blue value of sand is 0.05 g/100 g. The GTR classification of recycled sand is D2 which is insensitive to water and suitable for road applications. A mineralogical analysis of soil shows that quartz, albite and microcline are important minerals in recycled sand. XRF analysis shows that CaO and SiO<sub>2</sub> are major oxides in the recycled sand. The characterization of sand was followed by a manufacturing of cylindrical specimens of sand to observe the compressive strength. Samples were compacted with dynamic compaction by applying the Proctor normal energy of 600 kN·m/m<sup>3</sup>. The compressive strength testing of specimens shows that non-stabilized sand samples have compressive strength around 0.1 MPa which is considerably lower for its reuse in pedestrian pathways and road applications. Due to the low bearing capacity of sand, recycled sand was stabilized with the addition of binders such as Rolac (hydraulic binder), ground-granulated blast furnace slag (GGBS) and ECOSOIL<sup>®</sup> (slag mixes) with different percentages of the binder ranging from 0 to 7% for the optimization of the binder and for economic efficiency. The compressive strength of sand samples increases with the increasing percentage of the binder. The increase in strength is more important with a higher percentage of binders (5%, 6% and 7%). At a 7% binder addition, specimens with Rolac, GGBS and ECOSOIL binders show the compressive strength of 1.2 MPa, 0.5 MPa and 0.5 MPa. At a 7% Rolac addition, specimens have a compressive strength higher than 1 MPa and meet the strength requirement for soil reuse in the foundation and subbase layers of roads with low traffic. The experimental work shows that recycled sand can replace conventional quarry sand for road applications and pathways with the addition of a local binder, which is an eco-friendly and economical practice.
Flexible manufacturing systems (FMS) are highly adaptable production systems capable of producing a wide range of products in varying quantities. While this flexibility caters to evolving market demands, it also introduces complex scheduling and control challenges, making it difficult to optimize productivity, quality, and energy efficiency. This paper explores the application of digital twin technology to tackle these challenges and enhance FMS optimization and control. A digital twin, constructed by integrating simulation models, data acquisition, and machine learning algorithms, was employed to replicate the behavior of a real-world FMS. This digital twin enabled real-time dynamic optimization and adaptive control of manufacturing operations, facilitating informed decision making and proactive adjustments to optimize resource utilization and process efficiency. Computational experiments were conducted to evaluate the digital twin implementation on an FMS equipped with robotic material handling, CNC machines, and automated inspection. Results demonstrated that the digital twin significantly improved FMS performance. Productivity was enhanced by 14.53% compared to conventional methods, energy consumption was reduced by 13.9%, and quality was increased by 15.8% through intelligent machine coordination. The dynamic optimization and closed-loop control capabilities of the digital twin significantly improved overall equipment effectiveness. This research highlights the transformative potential of digital twins in smart manufacturing systems, paving the way for enhanced productivity, energy efficiency, and defect reduction. The digital twin paradigm offers valuable capabilities in modeling, prediction, optimization, and control, laying the foundation for next-generation FMS.
Aluminum alloy–graphene metal matrix composite is largely used for structural applications in the aerospace and space exploration sector. In this work, the preprocessed powder particles (AA 2014 and graphene) were used as a reinforcement material in a squeeze casting process. The powder mixture contained aluminum alloy powder 2014 with an average particle size of 25 μm and 0.5 wt% graphene nano powder (Grnp) with 10 nm (average) particle size. The powder mixture was mixed using the high-energy planetary ball milling (HEPBM) technique. The experimental results indicated that the novel mixture (AA 2014 and graphene powder) acted as a transporting agent of graphene particles, allowing them to disperse homogeneously in the stir pool in the final cast, resulting in the production of an isotropic composite material that could be considered for launch vehicle structural applications. Homogeneous dispersion of the graphene nanoparticles enhanced the interfacial bonding of 2014 matrix material, which resulted in particulate strengthening and the formation of a fine-grained microstructure in the casted composite plate. The mechanical properties of 0.5 wt% graphene-reinforced, hot-rolled composite plate was strengthened by the T6 condition. When compared to the values of unreinforced parent alloy, the ultimate tensile strength and the hardness value of the composite plate were found to be 420 MPa and 123 HRB, respectively.
We study the dynamics of the quantum battery capacity for the Bell-diagonal states under Markovian channels on the first subsystem. We show that the capacity increases for special Bell-diagonal states under amplitude damping channel. The sudden death of the capacity occurs under depolarizing channel. We also investigate the capacity evolution of Bell-diagonal states under Markovian channels on the first subsystem $n$ times. It is shown that the capacity under depolarizing channel decreases initially, then increases for small $n$ and tend to zero for large $n$. We find that under bit flip channel and amplitude damping channel, the quantum battery capacity of special Bell-diagonal states tends to a constant for large $n$, namely, the frozen capacity occurs. The dynamics of the capacity of the Bell-diagonal states under two independent same type local Markovian channels is also studied.
Recent research focuses on replacing metal current collectors with metallized polymer foils. However, this introduces significant challenges during cell production, as manufacturing steps must be adapted. Currently, copper is used as the current collector on the anode side and aluminum on the cathode side. These current collectors are then joined within the cell with an arrester tab. This step, known as contacting, is carried out industrially in pouch cells using ultrasonic welding or laser beam welding. However, since the polymer foil is electrically insulating, the current contacting procedures cannot be directly transferred to the metal–polymer current collectors. In this work, ultrasonic welding, laser beam welding, and a mechanical contacting method are considered, and the challenges arising from the material properties are highlighted. The properties of the joints are discussed as a function of the number of foils and the coating thickness of the metallization. It is demonstrated that successful contacting by ultrasonic welding and mechanical clamping is possible, as both mechanical strength and electrical conductivity are ensured by the joint. Laser beam welding was unsuccessful. Additionally, the electrical resistance is one to two orders of magnitude higher than that of pure aluminum and copper foils, which necessitates further optimization. Furthermore, ultrasonic welding is limited to welding 16 foils or fewer. This does not match industrial requirements. Consequently, novel approaches for contacting metal–polymer current collectors are required.
Volodymyr Gurey, Pavlo Maruschak, Ihor Hurey
et al.
Thermo-deformation treatment refers to methods of strengthening during which strengthened layers with a nanocrystalline structure are formed in the surface layers by modifying the metal surface layer, which changes its phase and structural and chemical compositions, reduces grain size, and improves performance. Grinding of the metal structure was achieved by combining two methods simultaneously during this treatment: the action of a highly concentrated energy source on the surface layer and intense plastic deformation. The source of highly concentrated energy was generated in the contact zone of the tool-disc, which rotates at high speed during friction on the treated surface. Intense deformation was achieved due to the grooves on the tool’s working surface. Dynamic analysis of the thermo-deformation treatment process of flat surfaces of machine parts and a calculation scheme of the surface grinder machine’s elastic system, which is the three-mass model, were developed. When the groove width increased from 4 mm to 8 mm, the force amplitude in the contact zone increased from 10 N to 75 N. Accordingly, the thickness of the nanocrystalline layer increased from 190–220 μm to 250–260 μm, and its hardness increased from 9.3 GPa to 11.1 GPa.
Alexander Graf, Verena Kräusel, Dieter Weise
et al.
Shearing high-strength steels often leads to a subpar cut quality and excessive stress on the tool components. To enhance the quality of the cut surface, intricate techniques like fine blanking are commonly employed. However, for applications with lower quality requirements, precision shear cutting offers an alternative solution. This research paper introduces a novel approach to directly superimpose radial stress on a workpiece during the precision shear cutting process and showcases for the first time how the application of direct stress superimposition can impact the cut surface by concurrently modifying the shear cutting edge and punch surface. A statistical experimental design is employed to investigate the interrelationships between the parameters and their effects. The results indicate that the overall cut quality, including cylindricity, clean-cut angle, rollover height, and tool stress, defined by punch force and retraction force, is influenced by the superimposed stress. Regarding the clean-cut zone, the statistical significance of direct radially superimposed stress was not observed, except when interacting with sheet thickness and clearance. Additionally, the sheet thickness and cutting gap emerged as significant parameters affecting the overall quality of the cut surface.
Bashar Huleihel, Oron Sabag, Haim H. Permuter
et al.
In this paper, we investigate the capacity of finite-state channels (FSCs) in presence of delayed feedback. We show that the capacity of a FSC with delayed feedback can be computed as that of a new FSC with instantaneous feedback and an extended state. Consequently, graph-based methods to obtain computable upper and lower bounds on the delayed feedback capacity of unifilar FSCs are proposed. Based on these methods, we establish that the capacity of the trapdoor channel with delayed feedback of two time instances is given by $\log_2(3/2)$. In addition, we derive an analytical upper bound on the delayed feedback capacity of the binary symmetric channel with a no consecutive ones input constraint. This bound also serves as a novel upper bound on its non-feedback capacity, which outperforms all previously known bounds. Lastly, we demonstrate that feedback does improve the capacity of the dicode erasure channel.
The thermoplastic polymer polyether ether ketone (PEEK) offers thermal and mechanical properties comparable to thermosetting polymers, while also being thermally re-processable and recyclable as well as compatible with fused filament fabrication (FFF). In this study, the feasibility of joining additively manufactured PEEK in pure and short carbon-fiber-reinforced form (CF-PEEK) is investigated. Coupon-level samples for both materials were fabricated using FFF with tailored integrated welding surfaces in the form of two different energy director (ED) shapes and joined through ultrasonic polymer welding. Using an energy-driven joining process, the two materials were systematically investigated with different welding parameters, such as welding force, oscillation amplitude and welding power, against the resulting weld quality. The strengths of the welded bonds were characterized using lap-shear tests and benchmarked against the monotonic properties of single 3D-printed samples, yielding ultimate lap-shear forces of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.17</mn></mrow></semantics></math></inline-formula><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">k</mi></semantics></math></inline-formula><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">N</mi></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.97</mn></mrow></semantics></math></inline-formula><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">k</mi></semantics></math></inline-formula><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">N</mi></semantics></math></inline-formula> and tensile strengths of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>3.24</mn></mrow></semantics></math></inline-formula><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">M</mi></semantics></math></inline-formula><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>Pa</mi></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>3.79</mn></mrow></semantics></math></inline-formula><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">M</mi></semantics></math></inline-formula><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>Pa</mi></semantics></math></inline-formula> for PEEK and CF-PEEK, respectively. The weld surfaces were microscopically imaged to characterize the failure behaviors of joints welded using different welding parameters. Samples welded with optimized welding parameters exhibited failures outside the welded region, indicating a higher weld-strength compared to that of the bulk. This study lays the foundation for using ultrasonic welding as a glue-free method to join 3D-printed high-performance thermoplastics to manufacture large load-bearing, as well as non-load-bearing, structures, while minimizing the time and cost limitations of FFF as a fabrication process.
Additive manufacturing (AM) has proven to be the preferred process over traditional processes in a wide range of industries. This review article focused on the progressive development of aero-turbine blades from conventional manufacturing processes to the additive manufacturing process. AM is known as a 3D printing process involving rapid prototyping and a layer-by-layer construction process that can develop a turbine blade with a wide variety of options to modify the turbine blade design and reduce the cost and weight compared to the conventional production mode. This article describes various AM techniques suitable for manufacturing high-temperature turbine blades such as selective laser melting, selective laser sintering, electron beam melting, laser engineering net shaping, and electron beam free form fabrication. The associated parameters of AM such as particle size and shape, powder bed density, residual stresses, porosity, and roughness are discussed here.