Conventional Process Research Articles

Source Range Estimation Using Linear Frequency-Difference Matched Field Processing in a Shallow Water Waveguide

Matched field processing (MFP) is an established technique for source localization in known multipath acoustic environments. Unfortunately, in many situations, imperfect knowledge of the actual propagation environment and sidelobes due to modal interference prevent accurate propagation modeling and source localization via MFP. To suppress the sidelobes and improve the method’s robustness, a linear frequency-difference matched field processing (LFDMFP) method for estimating the source range is proposed. A two-neighbor-frequency high-order cross-spectrum between the measurement and the replica of each hydrophone of the vertical line array is first computed. The cost function can then be derived from the dual summation or double integral of the high-order cross-spectrum with respect to the depth of the hydrophones and the candidate sources of the replicas, where the range that corresponds to the minimum is the optimal estimation. Because of the larger modal interference distances, LFDMFP can efficiently provide only one optimal range within the same range search interval rather than some conventional matched field processing. The efficiency of the presented method was verified using simulations and experiments. The LFDMFP unambiguously estimated the source range in two experimental datasets with average relative errors of 2.2 and 1.9%.

Co-design as participation: Creating meaningful pathways for collaboration in flood risk adaptation in Ohkay Owingeh Pueblo

Considering the detrimental effects caused by wildfires in New Mexico, there is a pressing need for the development of innovative hazard adaptation and mitigation strategies. Community-based approaches in hazard response have the potential to harness the power of co-design and the incorporation of traditional knowledge to help make conventional research and design process considerably less extractive. In this paper, we explore the elements of community based, bottom-up approaches that can support successful outcomes, in contrast to centralized top-down approaches. By offering a critical perspective of the idea that projects defined as bottom-up are inherently more effective than those that are top-down, we aim to amend a common participatory design framework, the double-diamond design method, and present a community-engaged framework on flood risk adaptation with the co-design of an environmental data dashboard to address this gap. This can be mitigated by employing a more human-centered design approach as a baseline, and further amending it to center community. We employed a series of workshops in Ohkay Owingeh Pueblo, in New Mexico, to integrate local knowledge. The goal of these workshops was to design an environmental data dashboard that would eventually serve as a point of information gathering and dissemination for the Pueblo. The workshops featured activities that worked to decolonize the process of co-design and put the Pueblo's needs at the center of the dashboard design process. The workshops allowed for participation in a variety of modalities – visual, verbal, auditory – giving community members space to lead and participate in many different formats.

Solution infiltrated lanthanum nickelate–GDC composite cathode via flash-light sintering for intermediate temperature solid oxide fuel cells

Solid oxide fuel cells (SOFCs) require high operating temperatures to minimize the oxygen reduction reaction resistance at cathode and increase the ionic conductivity of oxygen. However, at high operating temperatures, their stability during long-term operation degrades because of material deterioration and the mutual chemical reactions occurring at the interfaces. Herein, an electrode–electrolyte composite is fabricated by solution infiltration of lanthanum nickelate (LNO) electrode material into a GDC electrolyte layer to ensure more reaction sites compared with the conventional powder mixing of the electrode and electrolyte material. Further, the conventional thermal sintering process is replaced with the flash-light sintering process. Thus, the performance of the LNO–GDC cathode cell manufactured by flash-light sintering improves owing to suppression of grain growth of the infiltrated LNO particles. The microstructures of the infiltrated solution and composite layer of the electrolyte material are analyzed using field-emission scanning electron microscopy, and the crystallinity of the LNO nanoparticles is analyzed using high-resolution transmission electron microscopy. A maximum power density of 1.1 W/cm2 is achieved, an improvement of 58 % over the LSCF cell without infiltration at 750 ℃. This study is expected to contribute to the commercialization of SOFCs by replacing conventional thermal sintering.

Pretreatment and dyeability analysis of cotton and novel Bauhinia vahlii fiber

The textile industry is witnessing a paradigm shift towards sustainable materials, prompting the exploration of novel natural fibers as alternatives to synthetic fibers to meet environmental standards and address the growing demand for eco-friendly and sustainable products. Different natural fibers possess varied properties and are suitable for numerous applications in conventional and technical textiles. The coloration of these textile materials is an important aspect of conventional textiles, which starts with the pretreatment of the material. This study introduces a novel blend of cotton and Bauhinia vahlii fiber, a lesser-known natural cellulosic fiber with promising textile properties, and evaluates its pretreatment outcomes and dyeability characteristics. The study employs a systematic approach to pretreat the cotton and Bauhinia vahlii fiber blend (cotton: Bauhinia vahlii fiber 70:30) in a single bath using a conventional combined scouring bleaching process. The pretreatment process is carried out two times with varied sodium hydroxide (NaOH) and hydrogen peroxide (H2O2) concentrations for different processing times at 90 °C to assess the component fibers’ whiteness index, union bleaching balance, and weight loss percentage under diverse pretreatment conditions. Each time, 50% of the chemicals were used and continued for half of the processing time. The dyeability of the treated fibers is analyzed by dyeing the same in a single bath using amron bright red HF2R bifunctional reactive dye in varied shade depths (1%, 3%, and 5%) and fiber blend ratios (cotton: Bauhinia vahlii fiber 100:0, 90:10, 80:20, 70:30, and 0:100) to assess the color strength, union dyeing balance, and fastness properties. The maximum whiteness was achieved with 6 g per liter (gpl) of NaOH and H2O2 and at a processing time of 150 min with a whiteness index of 80.46 and 54.34 of cotton and Bauhinia vahlii fiber, respectively, with a union bleaching balance of 1.48. The dyed fibers’ colorimetric results confirm that Bauhinia vahlii fiber gives higher color strength than cotton fiber, irrespective of shade depth and blend ratio. The union dyeing balance of 1.2 was achieved at 5% shade depth with a 70:30 cotton Bauhinia vahlii fiber blend. This research contributes to the conventional textile field by introducing a sustainable fiber blend that reduces reliance on synthetic fiber and opens new avenues for utilizing Bauhinia vahlii fiber in conventional textile manufacturing.

The effect of temperature during plasma nitriding on the properties of IN718 additively manufactured by laser beam powder bed fusion

The IN718 superalloy has become a strategic alloy for applications in critical components in aerospace, oil, and gas, or power generation. Commercially, IN718 is produced by conventional casting processes. However, manufacturing is evolving towards 3D printing, which allows the manufacturing of near-net-shape parts and complex designs, thus optimizing manufacturing steps, reducing production costs, and adding other advantages to the final product. However, high corrosion resistance and mechanical strength are required in applications such as oil and gas, whereas IN718 superalloys have limitations. Surface hardening by applying plasma nitriding can protect against corrosion by increasing mechanical strength and wear resistance. For this, plasma nitriding has been widely applied for surface hardening of IN718; however, little is found on the effects of surface treatments (coating or nitriding) of additively manufactured alloys. The effects of temperature during plasma nitriding on the surface properties of IN718 superalloy 3D printed by the Laser Beam Powder Bed Fusion (LB-PBF) method are reported here. Samples of IN718 fabricated by 3D printing were plasma nitrided at fixed temperatures between 500 and 650 °C in a semi-industrial reactor, their effects are analyzed and correlated with their microstructural characteristics, the mechanical properties at the micro- and nanoscale, and the tribological responses in a pin-on-disk configuration.

Producing ‘The Right Candidate’: The Social Embeddedness of Labour Market Intermediaries for Migrant Workers in the Belgian Construction Sector

Structural labour shortages have increased demand for skilled and documented migrant workers in Western European labour markets. In response, private recruitment agencies are playing a more significant role in the identification, placement and integration of migrant workers. While the literature on labour intermediation practices has largely focused on the commercial and contractual work of matching workers with employers, this article develops an embedded understanding of labour intermediation that foregrounds the increasingly social and relational nature of intermediation practices in contexts of labour shortage. Through a qualitative study of intermediation in the Belgian construction sector, the article demonstrates the ways in which private agencies seek to produce the ‘right candidate’ through (i) the infiltration of migrant networks, (ii) the regularisation of migrant workers and (iii) the facilitation of their integration into host societies. These findings advance an expanded understanding of labour intermediation that transcends the conventional matchmaking process.

Performance and analysis of kappa-carrageenan hydrogel for PFOA-contaminated soil remediation wastewater treatment

Perfluorooctanoic acid is an emerging pollutant with exceptional resistance to degradation and detrimental environmental and health impacts. Conventional physical and chemical processes for Perfluorooctanoic acid are either expensive or inefficient. This study developed an environmentally sustainable and cost-effective gravity-driven kappa-carrageenan (kC)-based hydrogel for perfluorooctanoic acid (PFOA) removal from synthetic and actual wastewater. Two kC filters were prepared by mixing activated carbon (AC) or vanillin (V) with the kC hydrogel to optimize the hydrogel selectivity and water permeability. Experimental work revealed that the PFOA rejection and water permeability increased with the AC and V concentrations in the kC hydrogel. Experiments also evaluated the impact of feed pH, PFOA concentration, hydrogel composition, and hydrogel thickness on its performance. Due to pore size shrinkage, the AC-kC and V-kC hydrogels achieved the highest PFOA rejection at pH 4, whereas the water flux decreased. Increasing the PFOA concentration reduced water flux and increased PFOA rejection. For 2 cm hydrogel thickness, the water flux of 3%kC-0.3%AC and 3%kC-3%V hydrogels was 25.6 LMH and 21.5 LMH, and the corresponding PFOA rejection was 86.9% for 3%kC-0.3%AC and 85.7% for 3%kC-3%V. Finally, the kC-0.3%AC hydrogel removed 81.1% of PFOA from wastewater of 179 mg/L initial concentration compared to 79.3% for the kC-3%V hydrogel. After three filtration cycles, the water flux decline of 3%kC-0.3%AC was less than 10%. The gravity dead-end kC hydrogel provides sustainable PFOA wastewater treatment with biodegradable and natural materials.

Green recycling of end-of-life photovoltaic modules via Deep-Eutectic solvents

Sustainable End-of-life (EOL) photovoltaic (PV) modules recycling is essential for achieving resource conservation and alleviating environmental issues. Ethylene vinyle acetate (EVA) adhesive films separation is a prerequisite for the realization of valuable component recovery of PV modules. However, the conventional wet chemical separation processes are usually accompanied by the challenges of low separation efficiency, high toxicity and difficult multiple recycling. Herein, a green, biodegradable, low-cost and recyclable deep eutectic solvent (DES) is firstly developed to efficiently separate EVA films in EOL PV modules. The high temperature stability and the acidic characteristic of DES can facilitate the separation of EVA film between component layers. At 175 ℃, the warping effect caused by the differential thermal contraction between the module component layers creates favorable conditions for the efficient reaction and separation by the DES. Additionally, the acidic medium reacts with the aluminum electrode layer of PV cells, which further enhances the separation efficiency of EVA films. The EVA separation rate reached 100%, the separation rate of the EVA containing aluminum (Al) up to 98.4% after 12.5 h at 175 ℃. Moreover, the developed DES exhibits excellent recyclable performance, the EVA separation rate remained 100% after 10 cycles. Compared to the traditional solvent toluene, DES has advantages in terms of economics, environmental impact, and efficiency. This strategy of design a green, biodegradable, low-cost and recyclable solvent to replace traditional solvents, and provides a promising route to efficiently separate EVA films in EOL PV modules.

Developing three-dimensional hydrophobic photocatalysts to enhance mass transfer for promoting hydrogen peroxide production

Photocatalytic oxygen reduction reaction (ORR) is a promising approach for hydrogen peroxide (H2O2) production to alternative conventional anthraquinone process. However, the slow O2 diffusion and low-efficiency water oxidation reaction (WOR, limitation of protons) pathways have restricted the H2O2 production efficiency of organic photocatalysts. Therefore, a promising strategy to develop photocatalysts with three-dimensional (3D) architectures possessing high O2 diffusion, high-efficiency WOR pathway, and quick H2O2 desorption is desirable. Herein, a hydrophobic two-dimensional porous organic polymer (2D-POP) based on tetraphenylethylene (TPE) was synthesized as the building block. 3D-POPs (TPE-2 and TPE-3) were subsequently developed through the Friedel-Crafts alkylation reaction to regulate the O2 adsorption and optical properties. The 3D architectures allow O2 to diffuse into the interlayers, leading to efficient extraction of O2 from air, thus an excellent H2O2 production rate of 2.57 mmol g−1 h−1has been achieved by TPE-2 in air and without sacrificial agents, which only decreases by 4% compared to that in O2 due to a suitable specific surface area, good photoelectric properties, and excellent mass transfer of O2, H+, and H2O2. Furthermore, the H2O2 production rate of TPE-2 reaches 2.67 mmol g−1 h−1 in a triphasic system in air, which is higher than that in a traditional diphasic system, and the concentration of H2O2 reaches 1.80 mmol L−1 h−1. Additionally, by adding external Fe2+ or Fe3+ to make the utmost of photogenerated H2O2 and trigger the in-situ Fenton reaction for the formation of ·OH, TPE-2 exhibits extraordinary photodegradation efficiency toward representative organic pollutants, reaching > 99% removal within 60 min for bisphenol A and 2,4-dichlorophenoxyacetic acid with high concentrations (200 ppm).

Determination of the load acting on the probe by separating force and torque during FSW of AA 6060 T66

AbstractThe development of suitable welding processes is required to meet the ever-increasing demands on joining processes, particularly for lightweight construction and increasing environmental awareness. Friction stir welding (FSW) represents a promising alternative to conventional fusion welding processes, particularly for the joining of low-melting-point materials such as aluminium and magnesium alloys, which present a number of challenges, including the formation of pores and the occurrence of hot cracks. The central element of the process is the friction stir welding tool, which consists of a shoulder and a probe. The rotation and the simultaneous application of pressure during the joining process create a friction-based heat input through the tool. The excellent mechanical properties resulting from dynamic recrystallisation during the welding process are a major advantage of the process. As a result, strengths comparable to those of the base material can be achieved. However, FSW is subject to process-specific challenges, including high process forces, which result in the fabrication of complex and robust devices. Additionally, high dynamic loads on the friction stir welding tools must be considered. In many cases, the design of friction stir welding tools is based on empirical data. However, these empirical values are machine-, component- and material-specific, which often results in under- or overmatching of friction stir welding tools. Sudden probe failure, component scrap, and low process reliability are the direct consequences of undermatching. Overmatching results in enlarged tools with limited accessibility, high heat input, and high process forces, leading to component deformation. The aim of this study is to determine the load on the probe by separating the forces and torque of the shoulder and the probe in order to be able to make statements about the load acting on the probe and the resulting stress state. The knowledge of the stress state can be employed to design friction stir welding tools, both statically and dynamically, for a specific welding task. A strategy was devised to distribute the load exerted on the shoulder and probe. To this end, the length of the probe was gradually reduced between the welding tests. The investigations were carried out with a force-controlled robotized welding setup in which AA 6060 T66 sheets with a thickness of 5 mm were welded. A Kistler multicomponent dynamometer type 9139AA allows to measure the Cartesian forces to be recorded in the x-, y-, and z-directions with a sampling rate of 80 kHz. The weld seam properties were determined by visual and metallographic inspections as well as tensile and bending tests in accordance with DIN EN ISO 25239–5.

Thermal stability of a newly developed Mn containing β-solidifying γ-TiAl intermetallic compound at 750 °C

A newly low-cost β-solidifying γ-TiAl alloy Ti-44Al-3Mn-0.4Mo-0.4W-0.1B-0.1C (in at. %, named as TMMW) was invented. The rolled bars with a diameter of 12 mm were successfully fabricated by conventional hot rolling process, directly carrying out from the ingot without the pre-forging or hot-packing. The heat-treated TMMW rolled bar, which had a fine-grained nearly lamellar (NL) microstructure, was then air-exposed at 750 °C for up to 3000 h. The changes of the microstructure during this exposure were characterized using electron probe X-ray micro-analyzer (EPMA), transmission electron microscope (TEM), electron backscattered diffraction (EBSD) and high-energy X-ray diffraction (HEXRD). The tensile properties of the samples before and after thermal exposure were also tested. The fine-grained NL microstructure is found to be thermodynamically stable during the exposure. Meanwhile, the combined addition of Mo and W shows a positive effect on the stabilization of βo phase at colony boundaries, with only slight precipitation of the nanometer βo phases with no other brittle phases, such as Laves, in the metastable α2 lamellae. It is found that the thickness of the α2 lamellae decreases after 500 h exposure, while remains basically unchanged from 500 h to 3000 h, which is contributed by the effective pinning effect of the precipitated βo phase in α2 lamellae. As a result, the exposure-induced embrittlement under room temperature and elevated temperature does not take place. Interestingly, the ductility tested at 800 °C improves significantly after exposure. As for the tensile strength, it is only reduced by less than 10 % after 500 h exposure, while it remains essentially unchanged when increasing the exposure time from 500 h to 3000 h. Finally, the mechanisms of the precipitation of βo phases in the α2 lamellae and the tensile properties evolution during the exposure were carefully discussed.

Dual approach in textile wastewater treatment: optimisation and comparison of fluidised-bed and conventional Fenton processes

ABSTRACT This study optimises secondary textile dyeing wastewater removal using fluidised-bed Fenton (FBR-Fenton) and standard Fenton processes for chemical oxygen demand (COD) and colour removal efficiency. The Box–Behnken response surface approach optimised pH, iron ion concentration, and hydrogen peroxide concentration. At pH 3.3, [Fe2+] = 2.6 mm, [H2O2] = 6.4 mm in the fluidised bed reactor with 67 g/L quartz sand, with a 50% bed expansion after 40 min, the FBR-Fenton process removed 75.8% COD and 98.0% colour. The standard Fenton method was tuned to pH 3.2, [Fe2+] = 3.1 mm, [H2O2] = 6.6 mm, and COD and colour removal effectiveness of 69.7% and 97.5%, respectively. FBR-Fenton enhanced COD and total iron removal efficiency, reduced chemicals, and reduced sludge by 28.0% compared to conventional Fenton. This study also showed quartz sand reusability in FBR-Fenton treatment cycles. Experimental results matched response surface model predictions, proving regression equation correctness.

Investigation of the regulatory mechanism of monolayer colloidal crystals prepared by gas-liquid-solid three-phase interfacial self-assembly method

In recent years, the gas-liquid interface self-assembly method has emerged as a recognized and efficient technique for preparing two-dimensional monolayer colloidal crystals. However, challenges such as limited preparation area, dependence on complex equipment, and high costs persist in the conventional preparation process. This paper proposes a straightforward, rapid, and cost-effective method to implement a gas-liquid-solid three-phase interfacial self-assembly strategy. This approach enhances the gas-liquid interfacial self-assembly method, allowing for the preparation of large-area, high-quality single-layer colloidal crystals (>10 cm2) without using any surfactant. The gas-liquid-solid three-phase interfacial self-assembly process was analyzed in detail, and it was found that the main factors affecting the quality of the monolayer colloidal crystals were the volume ratio of PS colloidal solution to ethanol and the self-assembly temperature. It was shown that the optimal self-assembly conditions were achieved after dispersion by ultrasonic dispersion in a water bath at 32 °C–30 °C at a volume ratio of 1:2.5 of PS colloidal solution to ethanol. In addition, particles of various sizes can be prepared by this method to produce tightly arranged monolayer films that can be transferred to a variety of different substrates with great versatility. The demonstrated efficiency of this self-assembly method underscores its significant potential for application in large-scale manufacturing and practical industrialization.

Shadow Simulation of Quantum Processes.

We introduce the task of shadow process simulation, where the goal is to simulate the estimation of the expectation values of arbitrary quantum observables at the output of a target physical process. When the sender and receiver share random bits or other no-signaling resources, we show that the performance of shadow process simulation exceeds that of conventional process simulation protocols in a variety of scenarios including communication, noise simulation, and data compression. Remarkably, we find that there exist scenarios where shadow simulation provides increased statistical accuracy without any increase in the number of required samples.

Fabrication of conductive polyimide/metal composite fibers for high temperature EMI shielding

Surface metallization of high-performance polymer fibers via electroless plating represents a significant advancement in producing lightweight, flexible and durable electromagnetic interference (EMI) shielding fabrics. The conventional process for metallization of polyimide (PI) fibers faces challenges, including complex procedures and insufficient interfacial adhesion between the metal layer and fiber matrix. Herein, carboxylate-containing PI (PIC) fibers were developed to mitigate the mechanical degradation caused by traditional alkaline etching. Conductive composite fibers (PIC/Cu) were successfully produced through a continuous electroless copper plating process. The robust PIC/Cu interfacial bonding achieved based on nanoscale mechanical interlocking through Ni nanoparticles imparts excellent flexibility and durability, evidenced by only a 4 % increase in electrical resistance after 5000 bending cycles. The dense, uniform copper layer provides high conductivity (1.3 × 104 S/cm), resulting in an optimal EMI shielding efficiency of 63.4 dB for the corresponding fabric. Moreover, PIC/Cu-Ni fibers prepared by further electroless plating of nickel layer on the surface of PIC/Cu fibers demonstrate remarkable electrical stability across temperatures ranging from 50 to 350°C, with only a 1.2 % reduction in conductivity after exposure to 350°C for 1 h. These findings advance the development of high-performance conductive PI fibers for applications in aerospace vehicles and high-temperature environments.

Use of CO2 for enhanced carbon recovery in thermochemical processing of fruit peel waste

To address a supply variability associated with biomass, utilization of food waste provides a practical approach to consistently obtain carbon–neutral energy resource. Despite the technical merits of conventional biological process, the inevitable generation of less useful by-products, such as carbon dioxide (CO2) and sludge, remains a primary constraint. As an alternative, thermochemical process, such as pyrolysis, presents a promising solution for the comprehensive valorisation of food waste. In this study, citrus peel, one of the fruit processing wastes, was used as a model food waste. To enhance the eco-friendliness of the pyrolysis system, CO2 was introduced as a medium gas given the uncertainty regarding its behaviour as an inert or reactive agent at the pyrolysis temperatures. The pyrolysis approach demonstrated that CO2 interacts with volatile pyrogenic products, resulting in an increased formation of carbon monoxide (CO). Notably, this enhancement was observed at ≥ 400 °C, suggesting that CO2′s reactivity is limited at lower temperatures. To maximize the utility of CO2, the pyrolysis setup was modified by incorporating a heating block at 600 °C and a nickel-based catalyst (Ni/Al2O3). While these adjustments accelerated the thermal cracking of citrus peel, test setup modification led to an aromaticity increase of the resulting pyrogenic products. However, integrating CO2 into the catalytic pyrolysis created favourable conditions for detoxifying these aromatic compounds and further boosting CO production. Syngas productivity from catalytic pyrolysis in the presence of CO2 was 35.2 wt%, showing 3.67 times increase over that from conventional pyrolysis. In conclusion, CO2-assisted catalytic pyrolysis of the citrus peel offers significant technical benefits: it enhances carbon recovery in the form of CO and reduces the formation of undesirable aromatic pyrogenic products.

Enhancing the nitrogen removal of anammox sludge by setting up novel redox mediators-mediated anammox process

Anaerobic ammonium oxidizing (anammox) bacteria have been proven weak-electroactive. However, the impact of exogenous anthraquinone-2,6-disulfonate (AQDS) on the anammox activity, although it usually plays essential roles in the life activities of many other electroactive microorganisms, is still unknown. Therefore, this study further explored the influences of AQDS on the anammox activity and the interaction mechanism with anammox bacteria, as well as the behaviors of NH4+, NO2−, and NO3−. The results showed that exogenous AQDS increased the ammonium and total nitrogen removal rates by 12.8% and 10.7%, respectively. Interestingly, the conversion from NO2− to NO3− was significantly reduced after adding AQDS, resulting in a 40.1% reduction in NO3− production of anammox process. In this study, we found for the first time that anammox bacteria could not only carry out the conventional anammox process but also perform a weak redox mediator-mediated anammox process, which could achieve the 1:1 consumption of NH4+ and NO2−. The redox mediator-mediated anammox process was related to an endogenous redox mediator (ERM) synthesized and secreted by anammox bacteria, whose redox midpoint potential was around −0.26 V (vs. Ag/AgCl). After adding AQDS, not only the ERM-mediated anammox process was enhanced, but also two novel redox mediator-mediated anammox processes were introduced, including the AQDS-mediated anammox process and ERM-AQDS-mediated anammox process. These three redox mediator-mediated anammox processes significantly improved the nitrogen removal performance of anammox bacteria and reduced energy consumption. These findings will help reduce the dependence of anammox technology on NO2−, reduce the cost of subsequent treatment of NO3−, and provide new visions for optimizing and applying anammox technology.

Standoff-free vaporizing foil actuator welding: Process principle, experimental validation, and mechanisms analysis

This paper introduces a novel high-velocity impact welding process: the standoff-free vaporizing foil actuator welding (standoff-free VFAW). This technique employs a new type of driving mechanism, overcoming the geometric placement constraints between the flyer plate and the target plate inherent in conventional impact welding processes. It enables welding without requiring an initial standoff distance between the two plates. The feasibility and general applicability of the proposed process were validated through experiments. The welding performance was evaluated using shear tests, peel tests, and microstructural analysis. The results indicate that the proposed process can successfully weld T2 copper to 304 stainless steel and AA5083-H112 to 304 stainless steel. Additionally, this study verified that the proposed process can achieve progressive welding, making it possible to utilize standoff-free VFAW for large-area metal welding. Furthermore, microanalysis revealed the presence of a typical wavy interface characteristic at the joint. Key parameters influencing the welding results were also explored through experiments and finite element modeling, which suggest that the boundary constraints of the workpiece play a key role in the success of standoff-free VFAW. This implies that the initiation of the small and dynamic gap between the flyer and target plates could be the potential mechanism for the proposed process. In summary, standoff-free VFAW presents simplicity and efficiency as its advantages. Moreover, the insights gained from this technique are not limited solely to vaporizing foil actuator welding (VFAW) but could also provide reference points for other high-velocity impact welding techniques.

Active pharmaceutical contaminants in drinking water: myth or fact?

Global water availability has been affected by a variety of factors, including climate change, water pollution, urbanization, and population growth. These issues have been particularly acute in many parts of the world, where access to clean water remains a significant challenge. In this context, preserving existing water bodies is a critical priority. Numerous studies have demonstrated the inadequacy of conventional water treatment processes in removing active pharmaceutical ingredients (APIs) from the water. These pharmaceutical active compounds have been detected in treated wastewater, groundwater, and even drinking water sources. The presence of APIs in water resources poses a significant threat not only to aquatic organisms but also to human health. These emerging contaminants have the potential to disrupt endocrine systems, promote the development of antibiotic-resistant bacteria, and bioaccumulate in the food chain, ultimately leading to unacceptable risks to public health. The inability of current conventional treatment methods to effectively remove APIs from water has raised serious concerns about the safety and reliability of water supplies. This issue requires immediate attention and the development of more effective treatment technologies to safeguard the quality of water resources and protect both aquatic ecosystems and human health. Other treatment methods, such as nanotechnology, microalgal treatment, and reverse osmosis, are promising in addressing the issue of API contamination in water resources. These innovative approaches have demonstrated higher removal efficiencies for a wide range of APIs compared to conventional methods, such as activated sludge and chlorination, which have been found to be inadequate in the removal of these emerging contaminants. The potential of these alternative treatment technologies to serve as effective tertiary treatment. To address this critical challenge, governments and policymakers should prioritize investment in research and development to establish effective and scalable solutions for eliminating APIs from various water sources. This should include comprehensive studies to assess the performance, cost-effectiveness, and environmental sustainability of emerging treatment technologies. The emerging contaminants should be included in robust water quality monitoring programs (Aus der Beek et al. in Environ Toxicol Chem 2016;35(4):823-835), with strict regulatory limits enforced to protect public health and the environment. By doing so, the scientific community and regulatory authorities can work together to develop a multi-barrier approach to safeguarding the water resources and ensuring access to safe, clean water for all. This review explores the potential of alternative treatment technologies to serve as viable solutions in the fight against API contamination. Innovative approaches, including nanotechnology, microalgal treatment, and reverse osmosis, have demonstrated remarkable success in addressing this challenge, exhibiting higher removal efficiencies compared to traditional methods.

Some Possible Process Configurations for Modern Wastewater Treatment Plants for Per- and Polyfluoroalkyl Substances (PFASs) Removal

Per- and polyfluoroalkyl substances (PFASs) have been detected in the influent, effluent, and sludge/biosolids of wastewater treatment plants (WWTPs) globally. Due to their potential to bioaccumulate in humans, wildlife, and the environment over time owing to their seriously persistent nature and/or strong C-F bonds, PFASs can cause public health concerns. Conventional processes in full-scale WWTPs are usually inefficient in PFASs removal from wastewater and sludge, and advanced treatment technologies are needed for PFASs removal. This study intends to briefly (i) summarize the technologies for PFASs remediation in wastewater and sludge; (ii) review PFASs removal in full-scale WWTPs; (iii) discuss some possible theoretical configurations for the wastewater processing train of modern WWTPs for PFASs remediation; and finally (iv) provide future directions. Further research regarding the techno-economic assessment and optimization of treatment technologies in removing PFASs (especially short-chain PFASs) from real wastewater as well as the performance of full-scale WWTPs consisting of advanced innovative efficient treatment technologies for PFASs removal and associated costs (i.e., construction, operation, maintenance, chemical, energy, and amortization) is still required.