Processing Chain Research Articles

A systematic through-process rolling and extrusion study of four experimental high-strength Al-Mg-Si alloys

Al-Mg-Si alloys are an important class of Al wrought alloys. Further increasing their strength has significant economic potential. Previous approaches were focusing on increasing the amount of the main hardening elements Mg and Si, adding Cu and Zn for additional hardening potential, and adding dispersoid-forming elements such as Cr and Zr. In terms of processing, multi-step heat treatments and interrupted quenching have been pursued. Despite recent advances in the field, data points from the literature are difficult to compare due to widely varying alloy compositions and processing conditions. Here we present a comprehensive through-process rolling and extrusion study on four experimental high-strength Al-Mg-Si alloys (named A1–A4) with a particular focus on comparability of the results between our alloys and with the literature. Mechanical testing after artificial aging and in-depth microstructural investigations at various steps of the processing chain were employed, including scanning and transmission electron microscopy. We found that Cr addition leads to a strong increase in dispersoids and thus has a strong influence on hot workability, whereas the effect of increasing Mg and Si levels was negligible within the studied composition range. Al3Zr dispersoids were found to coexist with Al(Fe,Mn,Cr)Si dispersoids. Overall, the strength of the rolled sheets was slightly higher than that of the profiles. After 8 h of artificial aging at 180 °C, 2 mm thick sheet made of alloy A4, falling within the specification of AA6086, showed a notable yield strength of 393 MPa, due to nanoscale hardening phases that were smaller and appeared more numerous than in a commercial alloy (AA6082-T6).

Potentials of Polyacrylonitrile Substitution by Lignin for Continuous Manufactured Lignin/Polyacrylonitrile-Blend-Based Carbon Fibers

While carbon fibers (CFs) are still the most attractive reinforcement material for lightweight structures, they are mostly manufactured using crude oil-based process chains. To achieve a higher eco-efficiency, the partial substitution of polyacrylonitrile (PAN) by renewable materials, such as lignin, is investigated. So far, this investigation has only been carried out for batch manufacturing studies, neglecting the transfer and validation to continuous CF manufacturing. Therefore, this work is the first to investigate the possibility of partial substituting lignin for PAN in a continuous process. Lignin/PAN-blended CFs with up to 15 wt.-% lignin were able to attain mechanical properties comparable to unmodified PAN-based carbon fibers, achieving tensile strengths of up to 2466 MPa and a Young’s Modulus of 200 Pa. In summary, this study provides the basis for continuous Lignin/PAN-blended CF manufacturing.

Blockchain technology for advanced therapy medicinal products: Applications in tracking, data sharing, and supply chain automation

Advanced therapy medicinal products (ATMPs) like cell and gene therapies offer transformative treatment options for many diseases. However, coordinating the decentralized, patient-specific manufacturing of autologous ATMPs across multiple hospitals poses major supply chain challenges. This paper provides a comprehensive analysis of how blockchain technology can enhance decentralized ATMP manufacturing networks. First, background on ATMPs and complexities of decentralized production is reviewed. An overview of blockchain architecture, key attributes, and existing use cases then follows. The major opportunities for blockchain integration in ATMP manufacturing are discussed in depth, including tracking autologous products across locations, enabling data sharing between hospitals to power AI-based optimization, automating supply chain processes, and maintaining provenance records. Critical limitations around scalability, privacy, regulation, and adoption barriers are examined. Design considerations for developing blockchain ecosystems tailored to the unique ATMP environment are also explored. Blockchain shows immense promise for transforming visibility, coordination, automation, and data unification in decentralized ATMP manufacturing networks. Despite current challenges, blockchain is prepared to profoundly impact the advancement of personalized cell and gene therapies through enhanced supply chain instrumentation. This paper provides a comprehensive analysis of this emerging technological innovation and its applications to address critical needs in ATMP translation and manufacturing.

A comprehensive method of soaking sheepskins with sulfurization

Soaking is the first and one of the most important preparatory operations in fur dressing. Soaking determines the successful completion of subsequent technological processes. The purpose of soaking is to bring the skin into a state close to paired state in terms of the amount and uniformity of moisture distribution in the leather tissue and hair. This makes it important to find the optimal soaking recipe. The classic soaking method leads to damage to the structure of the dermis, due to which the structure of the soaked dermis differs from the structure of the dermis in the paired state. To solve this problem, it is necessary to find an innovative soaking method that both meets soaking standards and preserves the structure of the dermis close to the paired state. This article discusses a comprehensive method for soaking sheepskins with sulfurization. An experiment was conducted with 4 batches preserved using different preservation methods. These batches were soaked using our suggested recipe, using sodium sulfate and sulfuric acid. As a result of the interaction of sodium sulfate with sulfuric acid, sulfur is formed, which interacts with the functional groups of collagen. This interaction is one of the ways to sulfurize the semi-finished product. In addition, the resulting sulfur affects not only the soaking process, but also subsequent processes, causing synergy in the technological process chain. Analysis of the process results allows us to conclude that this soaking method complies with established standards. Since the watering of the raw material in each of the preservation methods is above 65%, as well as the indicators of the structure of the dermis, soaked with sulfur, are close to the indicators of the structure of the dermis in the paired state.

Preparation of fused silica glass micropatterns via gel method using quartz fiber as reinforcer

The preparation of fused silica glass with microstructural patterns has attracted considerable interest, and the process chain of using nano-silica powders mixed with organic polymers to prepare composites for molding, degreasing, and sintering provides a good solution. However, the potential negative effects of organic residues cannot be avoided. In this study, a pattern stencil replication method with silica gel using high-purity quartz fibers as reinforcement is proposed for preparing micropatterned fused silica glass. The microscopic morphology and mechanical properties before and after silica gel drying and the optical properties of fused silica glass obtained by sintering were evaluated via transmission electron microscopy), three-point bending strength test, scanning electron microscopy, X-ray diffraction spectrum analysis, ultraviolet–visible and infrared measurements. The results showed that quartz fiber as a reinforcer could shorten the drying time of the gel and did not degrade the quality of the fused silica glass obtained by sintering. Laser confocal test results showed that microlens arrays were generated by template replication, demonstrating the feasibility of molding fused silica lens arrays with small feature sizes and providing new ideas for the preparation of bulk fused silica glass or micropatterned glass.

Asynchronous filtering for discrete-time T–S fuzzy sampled-data systems with improved quantization

This study delves into the asynchronous filtering problem within discrete-time Takagi–Sugeno (T–S) fuzzy sampled-data systems featuring non-periodic sampled measurements. A non-homogeneous Markov chain is utilized to capture the stochastic nature of the sampling period. The transition probability matrix of this non-homogeneous Markov process is time-varying and characterized using a multi-mode structure. To mitigate conservatism, a quantizer associated with the modes is implemented, where the quantization density is defined as the observed modes. Unlike existing approaches, there exists a discrepancy between the quantizer mode and the sampling mode, following a hidden Markov chain process. Additionally, a novel fuzzy asynchronous filter is introduced based on the observed modes to ensure the stochastic stability of the fuzzy system. Ultimately, the effectiveness of the proposed filter strategy is validated via a tunnel diode circuit model.

Spherical polystyrene/zinc oxide nanocomposite powder fabricated by continuous process chain of melt mixing and indirect heating

Polymer powders are limited by particle size, shape, and properties in various applications. Preserving the chemical properties of the material throughout the process is a critical part of developing consistently shaped nanocomposite powders across diverse polymer types. The goal of this study is to demonstrate continuous methods to produce spherical Polystyrene (PS) and zinc oxide (ZnO) nanocomposites. A single-screw extruder is used to melt mix PS pellets with ZnO nanoparticles, followed by pelletization, dry grinding, and spheroidization in a Downer Tower to form spherical polymers. To minimize agglomeration, the process incorporates an ethanol treatment and a final sieving step. The resulting nanocomposite powder exhibits exceptional flowability and well-defined spherical morphology. Additionally, incorporating ZnO nanoparticles enhanced the thermal stability and glass transition temperature of the nanocomposite while reducing particle size distribution. Thermogravimetric analysis and X-ray diffraction confirm the preservation of the chemical structure of the spherical nanocomposite specimens throughout processing.

Cluster mediated high strength and large ductility in a strip casting micro-alloyed steel

Exhibiting exceptional mechanical properties and formability, high strength low alloy steels characterized by a single ferrite microstructure with finely dispersed nano-precipitates (ferritic HSLA steel) have garnered notable attention in the automotive industry. Nevertheless, to maximally utilize the precipitation hardening effect, these steels necessitate substantial additions of carbide-forming elements, unavoidably narrowing the process window and escalating the cost. Strip casting, featuring a streamlined process chain and high energy efficiency, has emerged as a promising technique for developing ferritic HSLA steels. In this work, leveraging the process characteristics of strip casting, we report that a novel single ferrite microstructure with multi-atomic layered clusters distributed in both interphase-precipitation and random fashions was engineered in a low Nb micro-alloyed ferritic HSLAs via raising the coiling temperature to 650 ℃. The multi-atomic layered clusters play a pivotal role in tailoring dislocation behaviors, facilitating local double cross-slips, contributing to dislocation multiplication and homogeneous distribution. These mechanisms collectively sustain mild work hardening to higher strains, leading to combined strength and ductility increments. In comparison to their cluster-free bainitic counterparts coiled at 480 ℃, the results demonstrate significant mechanical improvements with an increase in ultimate strength (630 MPa to 670 MPa) and a 90 % rise in plasticity (10.3 % to 19.1 %), signifying an alternative pathway for advancing the utilization of strip casting technology in designing and processing novel low-cost, high-performance HSLAs.

The Impact of Total Quality Management on Supply Chain Management in Five-Star Hotels in the Kingdom of Saudi Arabia

The research investigates the impact of Total Quality Management (TQM) on Supply Chain Management (SCM) in five-star hotels in Saudi Arabia, focusing on how integrating TQM principles can enhance operational efficiency, reduce costs, and improve customer satisfaction within the hospitality sector. The study emphasizes the convergence of TQM and SCM, highlighting continuous improvement, a culture of quality, and customer satisfaction as key impacts of TQM on SCM. TQM encourages organizations to evaluate and enhance processes continuously, leading to more streamlined and efficient supply chains. The integration of TQM principles into SCM processes aims to achieve higher levels of customer satisfaction, improved product quality, reduced costs, and increased operational efficiency. Several challenges in implementing TQM in Saudi five-star hotels are identified, including communication barriers, resistance to change, and resource constraints. The study proposes a comprehensive strategy for successful TQM and SCM integration, emphasizing leadership commitment, employee involvement, and the use of advanced technologies for real-time data sharing and performance monitoring. The findings are significant for hotel managers and decision-makers, providing evidence-based recommendations for implementing TQM principles to optimize supply chain processes. By adopting TQM practices, five-star hotels in Saudi Arabia can enhance their operational performance, achieve cost optimization, and ensure high levels of customer satisfaction, ultimately gaining a competitive advantage in the dynamic hospitality industry.

HCSRL: hyperledger composer system for reducing logistics losses in the pharmaceutical product supply chain using a blockchain-based approach

Blockchain technology uses a secure and decentralised framework for transaction management and data sharing within supply chains. This is particularly crucial in the pharmaceutical industry, where product authenticity and traceability are paramount. Blockchain plays a pivotal role in preventing product loss and counterfeiting, while simultaneously enhancing transparency and efficiency throughout the supply chain. The research introduces a step-by-step approach to implementing a proof-of-concept (PoC) for Supply Chain Risk Management (SCRM) through blockchain technology. This PoC involves simulating a supply chain process to assess feasibility and measure key performance indicators. Engaging stakeholders and gathering feedback is integral to refining the blockchain-based SCRM system. The study rigorously evaluates the performance of the SCRM blockchain across various test scenarios, featuring differing numbers of organizations and clients. Multiple fabric networks are employed to assess the system’s scalability and performance under diverse conditions. The results of these comprehensive tests inform practical deployment decisions and highlight areas for potential optimization and further development. So this research provides valuable insights into the application of blockchain in pharmaceutical supply chains, offering a roadmap for implementation and improving supply chain security, efficiency, and transparency.

Lossy Compression of Single-channel Noisy Images by Modern Coders

Lossy compression of remote-sensing images is a typical stage in their processing chain. In design or selection of methods for lossy compression, it is commonly assumed that images are noise-free. Meanwhile, there are many practical situations where an image or a set of its components are noisy. This fact needs to be taken into account since noise presence leads to specific effects in lossy compressed data. The main effect is the possible existence of the optimal operation point (OOP) shown for JPEG, JPEG2000, some coders based on the discrete cosine transform (DCT), and the better portable graphics (BPG) encoder. However, the performance of such modern coders as AVIF and HEIF with application to noisy images has not been studied yet. In this paper, analysis is carried out for the case of additive white Gaussian noise. We demonstrate that OOP can exist for AVIF and HEIF and the performance characteristics in it are quite similar to those for the BPG encoder. OOP exists with a higher probability for images of simpler structure and/or high-intensity noise, and this takes place according to different metrics including visual quality ones. The problems of providing lossy compression by AVIF or HEIF are shown and an initial solution is proposed. Examples for test and real-life remote-sensing images are presented.

Innovative biorefinery approaches for upcycling of post-consumer food waste in a circular bioeconomy context

Owing to the significant amounts produced each year, food waste is a critical issue that affects the economy, society, and environment. An estimated US$ 1 trillion food is wasted annually because of the supply chain and harvesting processes, which lose around one-third of the net production. This significant loss has sparked global concern, there is an urgent need for sustainable approaches to reduce food waste or to propose an economical route for its utilization. Major concerns associated with its improper management include environmental degradation and the exacerbation of greenhouse gases. This review provides a comprehensive understanding of the recent advances in measures to minimize food waste (FW) and its chemical and biotransformation into valuable products. Food waste comprises mainly carbohydrates, proteins, and oils; the former two components are commonly used as microbial feedstock, leaving behind the residual oil fraction which poses a greater environmental risk. Microbial transformation of these hydrophobic materials present in food waste into value-added products proves to be a sustainable and economical strategy. Thus, this study proposes an integrated biorefinery strategy for holistic valorization of FW, whereby all its components were used to produce value-added compounds such as biofuels, bioplastics, nutraceuticals, and biomaterials using microbial biocatalysis. Compared to conventional methods, an integrated biorefinery will be more sustainable and uplift the microbial processes by switching from ‘pure’ to food waste-derived substrates and thereby pave ways to achieve ‘green’ transition.

Plastic takeaway food containers may cause human intestinal damage in routine life usage: Microplastics formation and cytotoxic effect

The microplastics and organic additives formed in routine use of plastic takeaway food containers may pose significant health risks. Thus, we collected plastic containers made of polystyrene, polypropylene, polyethylene terephthalate, polylactic acid and simulated two thermal usages, including hot water (I) and microwave treatments (M). Nile Red fluorescence staining was developed to improve accurate counting of microplastics with the aid of TEM and DLS analysis. The quantity of MPs released from thermal treatments was determined ranging from 285.7 thousand items/cm2 to 681.5 thousand items/cm2 in containers loaded with hot water with the following order: IPS>IPP>IPET>IPLA, while microwave treatment showed lower values ranging from 171.9 thousand items/cm2 to 301.6 thousand items/cm2. In vitro toxicity test using human intestinal epithelial Caco-2 cells indicated decrease of cell viability in raw leachate, resuspended MPs and supernatants, which might further lead to cell membrane rupture, ROS production, and decreased mitochondrial membrane potential. Moreover, the leachate inhibited the expression of key genes in the electron transport chain (ETC) process, disrupted energy metabolism. For the first time, we isolate the actually released microplastics and organic substances for in vitro toxicity testing, and demonstrate their potential impacts to human intestine. SynopsisPlastic take-out containers may release microplastics and organic substances during daily usage, both of which can cause individual and combined cytotoxic effects on human colon adenocarcinoma cells Caco-2.

Can a complete excision of the injured site of the spinal cord lead to positive results?

Until now, there are no successful ways to restore the damaged spinal cord and its functions in severe spinal cord injury such as spinal cord contusion, rupture or intersection. This is largely due to the lack of treatment methods aimed at the chain of pathogenetic processes occurring in the nervous tissue after injury. The topic of restoration of spinal cord functions is taboo, often undesirable for discussion, and is influenced by clinical stereotypes. The article proposes to consider the method of treatment of spinal cord injury, using modern data, taking into account emerging pathophysiological processes at the site of injury and beyond. The use of new data and achievements of experimental science on severe spinal cord injury can be a serious step towards the development of new methods for the treatment of this pathology.

The effect on the carbon footprint of the rice-wheat system of substituting chemical fertilizers by pig manure: The results of a field experiment

Livestock manure is widely recycled to enhance intensive agricultural production. Nevertheless, the environmental and agronomic benefits of liquid manure, such as biogas slurry, have rarely been comprehensively evaluated. To boost food production while maintaining environmental sustainability, a field experiment was performed to assess the effects of solid and liquid manure substitution for chemical fertilizer on direct greenhouse gas (GHG) emissions, soil organic carbon (SOC), grain yield, and carbon footprints (CF) in a rice-wheat system. The treatments involved only chemical fertilizer (NPK), 50 % NPK + 50 % pig manure (50 % PM), 100 % pig manure (100%PM), 50 % NPK + 50 % biogas slurry from PM (50 % PS), and 100 % biogas slurry from PM (100 % PS) in the circumstances of equal nitrogen fertilization. The results showed that rice CH4 emissions dominated the direct GHG emissions, and followed the order of 100%PM > 50%PM > 50%PS = NPK = 100%PS on average of three years. The 100%PM had the highest area-scaled CF with 11.84 Mg CO2-eq ha−1 due to high CH4 emissions and carbon emissions from pig manure production and compost indirectly without considering the changes in SOC stock. Meanwhile, 100%PM significantly increased SOC stock at 0–30 cm depth by 49.1 %, 11.8 %, 44.8 %, and 56.5 % compared with NPK, 50%PM, 50%PS, and 100%PS, respectively (P < 0.05). Notably, 100 % PM had the lowest area-scaled CF with 0.99 Mg CO2-eq ha−1 when considering the changes in SOC stock, followed by 50%PM. The 50%PM significantly increased the annual grain yield of rice and wheat from 2010 to 2018, with an average of 4.9 %, 4.5 %, and 5.7 % compared with NPK, 100%PM, and 100%PS, respectively (P < 0.05). Overall, although there was a trade-off between SOC sequestration and CH4 emissions under pig manure, pig manure substitution for chemical fertilizer significantly decreased yield-scaled CF, followed by biogas slurry substitution relative to NPK (P < 0.05). Thus, pig manure substitution for chemical fertilizer is recommended for environmental and yield benefits simultaneously considering the whole chain of production process in a rice-wheat system. In future, strategic fertilizer management based on PM and PS could potentially offer a sustainable solution to mitigate the trade-off and sustain the respective benefits of PM (i.e. SOC and grain yield) and PS (i.e. CH4 emissions).

The Chain of Processes Forming Porphyry Copper Deposits—An Invited Paper

Abstract Porphyry-related mineral deposits are giant geochemical anomalies in the Earth’s crust with orders-of-magnitude differences in the content and proportion of the three main ore metals Cu, Au, and Mo. Deposit formation a few kilometers below surface is the product of a chain of geologic processes operating at different scales in space and time. This paper explores each process in this chain with regard to optimizing the chances of forming these rare anomalies. On the lithosphere scale, deposits with distinct metal ratios occur in provinces that formed during brief times of change in plate motions. Similar metal ratios of several deposits in such provinces compared with global rock reservoirs suggest preceding enrichment of Au or Mo in lithospheric regions giving rise to distinct ore provinces. The largest Cu-dominated deposits and provinces are traditionally explained by selective removal of Au during generation or subsequent evolution of mantle magmas, but the possibility of selective Cu pre-enrichment of lithosphere regions by long-term subduction cannot be dismissed, even though its mechanism remains speculative. Evolution of hydrous basaltic melts to fertile magmas forming porphyry Cu deposits requires fractionation toward more H2O-rich magmas in the lower crust, as shown by their adakite-like trace element composition. The prevailing interpretation that this fractionation leads to significant loss of chalcophile ore metals by saturation and removal of magmatic sulfide might be inverted to a metal enrichment step, if the saturating sulfides are physically entrained with the melt fraction of rapidly ascending magmas. Ascent of fertile magma delivers a large mass of H2O-rich ore fluid to the upper crust, along points of weakness in an overall compressive stress regime, within a limited duration as required by mass and heat balance constraints. Two mechanisms of rapid magma ascent are in debate: (1) wholesale emplacement of highly fractionated and volatile-rich granitic melt into a massive transcrustal channelway, from which fluids are exsolved by decompression starting in the lower crust, or (2) partly fractionated magmas filling a large upper crustal magma chamber, from which fluids are expelled by cooling and crystallization. Transfer of ore-forming components to a hydrothermal ore fluid is optimized if the first saturating fluid is dense and Cl rich. This can be achieved by fluid saturation at high pressure, or after a moderately H2O rich intermediate-composition melt further crystallizes in an upper crustal reservoir before reaching fluid saturation. In either case, metals and S (needed for later hydrothermal sulfide precipitation) are transferred to the fluid together, no matter whether ore components are extracted from the silicate melt or liberated to the ore fluid by decomposition of magmatic sulfides. Production and physical focusing of fluids in a crystallizing upper crustal magma chamber are controlled by the rate of heat loss to surrounding rocks. Fluid focusing, requiring large-scale lateral flow, spontaneously occurs in mushy magma because high water content and intermediate melt/crystal ratio support a network of interconnected tubes at the scale of mineral grains. Calculated cooling times of such fluid-producing magma reservoirs agree with the duration of hydrothermal ore formation measured by high-precision zircon geochronology, and both relate to the size of ore deposits. Ore mineral precipitation requires controlled flow of S- and metal-rich fluids through a vein network, as shown by fluid inclusion studies. The degree of hydrothermal metal enrichment is optimized by the balance between fluid advection and the efficiency of cooling of the magmatic fluid plume by heat loss to convecting meteoric water. The depth of fluid production below surface controls the pressure-temperature (P-T) evolution along the upflow path of magmatic fluids. Different evolution paths controlling density, salinity, and phase state of fluids contribute to selective metal precipitation: porphyry Au deposits can form at shallow subvolcanic levels from extremely saline brine or salt melt; high-grade Au-Cu coprecipitation from coexisting and possibly rehomogenizing brine and vapor is most efficient at a depth of a few kilometers; whereas fluids cooling at greater depth tend to precipitate Cu ± Mo but transport Au selectively to shallower epithermal levels. Exhumation and secondary oxidation and enrichment by groundwater finally determine the economics of a deposit, as well as the global potential of undiscovered metal resources available for future mining.

Impact of strand deposition and infill strategies on the properties of monolithic copper via material extrusion additive manufacturing

The present research presents a comprehensive study on the process optimisation and characterisation of fully dense and pure Cu parts manufactured by Material Extrusion Additive Manufacturing (MEX). This technology is an emerging approach to additively manufacture high-performance metal components due to its multi-step nature that allows to shape and subsequently sinter complex design parts. A commercially available filament with 60 vol% (93 wt%) copper particles and polymeric binders was used and characterised in this study. Two approaches were combined for the first time to maximise the final density of the copper parts; a statistical approach (using ANOVA) and an optimisation approach based on the strand cross-section. Based on the former, the flow rate multiplier during printing has a significant effect on the density of the as-printed parts. The latter aimed at studying the effect of the ratio between extrusion width, layer height, and nozzle diameter on the deposited strand morphology. An extrusion width equal to and a layer height lower than the nozzle diameter contribute to precise strand dimensions, leading to improved control of the final green density. After solvent and thermal debinding followed by pressureless and supportless sintering in pure H2 at 1050 °C, the copper parts resulted in a relative density > 95 % and an electrical conductivity of ∼93 %IACS as an indication of the purity of the starting material and the quality of the whole process chain. Tensile testing of as-sintered dog-bone samples, built with 0°, 90° and ±45° infill patterns and a single wall contour, revealed the best results for the ±45° strategy with an ultimate tensile strength of 164 MPa and an elongation at fracture of 24 %. Finally, a copper coil for electromagnetic applications was manufactured, for the first time, via filament-based MEX and tested. It reported an electrical conductivity competitive to that reported in the literature (∼70 %IACS). This result was discussed in relation to a simple monolithic Cu geometry to provide insight into the complexity and concomitant scientific relevance of applying MEX to functional components.

Assessment of process chain suitability of the optical 3D measuring system by using influencing factors for measurement uncertainty

Optical 3D measuring systems serve as indispensable tools for the measurement and quality control of complex objects feeding process chains in industrial information integration. However, the accuracy of 3D measurements is influenced by a multitude of parameters, and the associated measurement uncertainties and influential factors remain insufficiently researched. This study investigates the effects of measurement object properties and software on measurement outcomes. Specifically, we examine seven geometries (diameter, distance, roundness, concentricity, flatness, parallelism and verticality) and four influencing factors (surface roughness, coating, polygonization, and interpolation). Our analysis employs variance analysis and compares the results with those obtained through linear regression using machine learning. In conclusion, the analysis of measurement uncertainty for optical 3D measurement systems in the assessment of seven distinct geometric characteristics provides a framework for determination of process chain suitability of the optical 3D measuring system.

Integration of soft tooling by additive manufacturing in polymer profile extrusion process chain

Integrating additive manufacturing (AM) into polymer extrusion offers process chain flexibility and design freedom. It reduces the need for time-consuming iterations and trial-and-error in the die design process. Consequently, polymer AM of extrusion (i.e., soft tooling) allows for a shorter product development cycle and cost-effectiveness for small-scale production and highly customized products. In this study, carbon fibre (CF)-polyether-ether-ketone (PEEK) dies were manufactured using the fused filament fabrication (FFF) AM process, employing a streamlined die design achieved through freeform transition planes. Calibration slides were produced using masked stereolithography (MSLA), FFF, and conventional manufacturing techniques (i.e., machining) to preserve the final product’s cross-section during the cooling process. The dimensional and surface characteristics of these calibration slides were evaluated to assess the dimensional accuracy and surface topography of various materials and manufacturing processes. The dimensional evaluation reveals that MSLA-printed parts exhibit deviation from the nominal dimension closer to the conventionally manufactured part. The integrated soft tooling in the polymer extrusion line was tested with polypropylene (PP) and acrylonitrile butadiene styrene (ABS) as extruded materials. The surface topography of the CF-PEEK die displays distinctive ripple features resulting from the FFF process, identified by relatively flat peaks and deep valleys. The overall surface texture parameter values of CF-PEEK were higher due to the presence of deep valleys. Considering that the areas around the peaks interacted more with polymer molecules during the extrusion, the surface texture parameters of the extrudates were closer to the value observed in 90 µm region areas around the peaks. Notably, extrudates of AM calibration slides have lower surface texture parameters than extrudates of conventionally manufactured calibration slides, even though surface defects in the form of dimple sink marks were observed in extruded material of PP from extrudates using AM calibration slides.

Operational Angular Track Reconstruction in Space Surveillance Radars through an Adaptive Beamforming Approach

In the last few years, many space surveillance initiatives have started to consider the problem represented by resident space object overpopulation. In particular, the European Space Surveillance and Tracking (EUSST) consortium is in charge of providing services like collision avoidance, fragmentation analysis, and re-entry, which rely on measurements obtained through ground-based sensors. BIRALES is an Italian survey radar belonging to the EUSST framework and is capable of providing measurements including Doppler shift, slant range, and angular profile. In recent years, the Music Approach for Track Estimate and Refinement (MATER) algorithm has been developed to retrieve angular tracks through an adaptive beamforming technique, guaranteeing the generation of more accurate and robust measurements with respect to the previous static beamforming approach. This work presents the design of a new data processing chain to be used by BIRALES to compute the angular track. The signal acquired by the BIRALES receiver array is down-converted and the receiver bandwidth is split into multiple channels, in order to maximize the signal-to-noise ratio of the measurements. Then, the signal passes through a detection block, where an isolation procedure creates, for each epoch, signal correlation matrices (CMs) related to the channels involved in the detection and then processes them to isolate the data stream related to a single detected source. Consequently, for each epoch and for each detected source, just the CM featuring the largest signal contribution is kept, allowing deriving the Doppler shift measurement from the channel illumination sequence. The MATER algorithm is applied to each CM stream, first estimating the signal directions of arrival, then grouping them in the observation time window, and eventually returning the target angular track. Ambiguous estimates may be present due to the configuration of the receiver array, which cause spatial aliasing phenomena. This problem can be addressed by either exploiting transit prediction (in the case of cataloged objects), or by applying tailored criteria (for uncatalogued objects). The performance of the new architecture was assessed in real operational scenarios, demonstrating the enhancement represented by the implementation of the channelization strategy, as well as the angular measurement accuracy returned by MATER, in both nominal and off-nominal scenarios.