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Cellulose paper, a material that is naturally derived, low cost, lightweight, eco-friendly, and mechanically deformable, plays important roles in producing next-generation flexible electronics. Following the booms in the development of functional electronics, the soft actuators built from cellulose paper have attracted great attention. In this focused review, the milestones and recent achievements of cellulose paper-based actuators are summarized. Electro-, thermal, moisture and magnetic actuation mechanisms are utilized to acquire energy from external stimuli. Corresponding functional materials and available fabrication techniques like film assembly and layer deposition are described. Programmable actions for the emerging applications in bionics, paper grippers and robots are realized by pursuing different strategies to control the responding deformation. Along with a conclusion, the existing challenges and possible solutions in evaluating and improving the performance of cellulose paper are summarized in the final section.

Bulk graphitic carbon materials with expanded interlayer spacing and abundant defects may serve as efficient anodes with high areal capacities for sodium-ion batteries (SIBs). However, obtaining long-range order in bulk graphitic carbon materials with expanded interlayer spacing is extremely difficult. Herein, an explosive decomposition method is demonstrated to realize thermally reduced graphene oxide (rGO) paper with tuned interlayer spacing. The in-situ temperature-dependent X-ray diffraction (td-XRD) was utilized to establish the correlation between heating rate and interlayer spacing. Based on td-XRD results, free-standing graphene paper (FSG) was synthesized at 450°C under a high heating rate of 70°C/min. The FSG exhibits a highly porous structure made of graphene flakes with abundant surface epoxy groups with an overall interlayer spacing of 0.38–0.39 nm. The rGO flakes in FSG are separated by large voids that provide fast mass transport pathways and allow expansion/contraction of crystallites upon reversible Na intercalation. The FSG was utilized directly as anodes without any binder and conductive agent and delivered an excellent reversible capacity of 290 mAh/g at a current density of 50 mA/g. Moreover, the FSG exhibited excellent foldability and rollability to create high areal density anodes, delivering an areal capacity of 0.62 mAh/cm2 at a current density of 100 μA/cm2. These results open the door to fabricate graphene material-based carbon anodes with tunable interlayer spacing for high-performance SIBs.

Vine tea has been used as an herbal tea by several ethnic minorities for hundreds of years in China. Flavonoids, a kind of indispensable component in a variety of nutraceutical, pharmaceutical and cosmetic applications, are identified to be the major metabolites and bioactive ingredients in vine tea. Interestingly, vine tea exhibits a wide range of significant bioactivities including anti-oxidant, anti-inflammatory, anti-tumor, antidiabetic, neuroprotective and other activities, but no toxicity. These bioactivities, to some extent, enrich the understanding about the role of vine tea in disease prevention and therapy. The health benefits of vine tea, particularly dihydromyricetin and myricetin, are widely investigated. However, there is currently no comprehensive review available on vine tea. Therefore, this report summarizes the most recent studies investigating bioactive constituents, pharmacological effects and possible mechanisms of vine tea, which will provide a better understanding about the health benefits and preclinical assessment of novel application of vine tea., Graphical abstract Image 1, Highlights • Vine tea has been consumed as a folk herbal tea for hundreds of years. • Flavonoids were the major bioactive ingredients in vine tea. • Dihydromyricetin and myricetin are major bioactives in vine tea. • Vine tea exhibits a wide range of significant bioactivities. • Vine tea may be a potential, functional herbal tea.

Coated microneedles (MNs) are widely used for delivering biopharmaceuticals. In this study, a novel gel encapsulated coated MNs (GEC-MNs) was developed. The water-soluble drug coating was encapsulated with sodium alginate (SA) in situ complexation gel. The manufacturing process of GEC-MNs was optimized for mass production. Compared to the water-soluble coated MNs (72.02% ± 11.49%), the drug delivery efficiency of the optimized GEC-MNs (88.42% ± 6.72%) was steadily increased, and this improvement was investigated through in vitro drug release. The sustained-release of BSA was observed in vitro permeation through the skin. The rhIFNα-1b GEC-MNs was confirmed to achieve biosafety and 6-month storage stability. Pharmacokinetics of rhIFNα-1b in GEC-MNs showed a linearly dose-dependent relationship. The AUC of rhIFNα-1b in GEC-MNs (4.51 ng/ml·h) was bioequivalent to the intradermal (ID) injection (5.36 ng/ml·h) and significantly higher than water-soluble coated MNs (3.12 ng/ml·h). The rhIFNα-1b elimination half-life of GEC-MNs, soluble coated MNs, and ID injection was 18.16, 1.44, and 2.53 h, respectively. The complexation-based GEC-MNs have proved to be more efficient, stable, and achieve the sustained-release of water-soluble drug in coating MNs, constituting a high value to biopharmaceutical., Graphical abstract In the coated microneedle produced by the layer-by-layer coating method, the water-soluble drug-containing coating is encapsulated by the complexation-based gel (GEC-MNs). After GEC-MNs are applied to the skin, the release rate of the drug is reduced by the outer layer of the gel. The pharmacokinetic results of rh-IFNα-1b showed that compared with intradermal injection and water-soluble coated microneedles, the sustained release was achieved in GEC-MNs.Image, graphical abstract

In quest of meeting the requirements of sustainable development, coupling zero valent iron (ZVI) with microorganisms has attracted extensive attentions for enhancing biological wastewater and sludge treatment in terms of microbial growth, nutrients removal, and resources recovery. Given to the significant role of ZVI playing in biological wastewater and sludge treatment, a thorough evaluation of the associated interactions among ZVI and microorganisms is necessary to further scale-up the application of ZVI-based biotechnologies. To this end, this review comprehensively summarizes the mechanisms of ZVI for enhancing nutrients removal (i.e., C, N, S and P) in several typical biological wastewater treatment processes, discusses the role of ZVI in improving the excess sludge reduction by dewatering or anaerobic digestion for methane production, and analyzes the feasibility of recovering phosphorus from anaerobic sludge digestion system in the form of vivianite through using ZVI. Knowledge gaps regarding the application of ZVI in sludge or wastewater treatment are also identified in this review to facilitate the further development of the ZVI-based biological technology.

The exploitation of natural quarries generates a high amount of waste as a result of the extraction, screening and segmentation processes. These usually inert wastes are not typically reused and end up in landfills. There is an urgent need for sustainable solutions aiming at the valorisation of these mineral wastes through the development of innovative products with greater added value and active functionalities. In this work, the applicability of different mineral wastes was tested on the development of advanced active ecocomposites. Several formulations/ conditions, using green epoxy and polyester matrixes, were assessed in order to determine the reasonable production parameters. Additionally, two different antibacterial agents were added and the efficacy was tested. The overall mechanical performance of the ecocomposite was evaluated during every stage of development. The combination of dried sludge and green epoxy resin (SE_70), containing 70% of mineral waste, revealed to be most promising composition with interesting mechanical properties (tensile strength 91.63 ± 3.31 (MPa); strain (%) 0.69 ± 0.05; and Young’s modulus (GPa) 13.65 ± 0.64). The functionalization of these samples was successful and the antibacterial activity was confirmed. However, the active agent affected the short-term mechanical properties. Nevertheless, the QUV® accelerated weathering test confirmed that the main long-term properties were unaffected. Thus, it is concluded that mineral waste from quarry activities can be use in the development of new sustainable added value advanced products., This work was supported by Operational Programme “Regional Azores 2014–2020”, through project Basalt Waste Composite (ACORES01-0247-FEDER-000013), Portugal.

In this work, a novel delignification process was proposed for the fractionation of invasive species such as Acacia dealbata wood. Organosolv process catalyzed with an acidic ionic liquid, 1-butyl-3-methylimidazolium hydrosulfate was evaluated to obtain cellulose-enriched solids and liquid fractions rich in hemicelluloses derived compounds and lignin. Under selected operating conditions (190 °C, 60% ethanol, 60 min of reaction time and 0.6 g 1-butyl-3-methylimidazolium hydrosulfate/g wood), high solubilization of lignin and hemicelluloses and cellulose recovery (87.5%, 88.7% and 88.3%, respectively), with a pulp yield of 43.1% were achieved. Moreover, 62.6 % of lignin was recovered by precipitation from the black liquor (composed mainly by 4.43 g xylose/L, 7.66 g furfural/L and 3.59 g acetic acid/L). In addition, enzymatic digestibility of delignified wood was also assayed. Overall, this work presents an alternative biorefinery scheme based in the use of environmentally friendly solvent and catalyst for selective fractionation of A. dealbata wood., The authors acknowledge the financial support received from the Spanish “Ministry of Economy and Competitiveness” (Project CTQ2017-82962-R) and from “Xunta de Galicia” (GRC ED431C 2018/47 and Centro Singular de Investigación Biomédica “CINBIO”). These projects are partially funded by the FEDER Program of the European Union (“Unha maneira de facer Europa”). A. Romaní thanks BioTecNorte operation (NORTE-01–0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte., info:eu-repo/semantics/publishedVersion

[EN] Nitrogen recovery technologies such as the hollow fibre membrane contactor are now being developed. However, an economic analysis is needed prior to their full-scale application in wastewater treatment plants. The aim of this study was to analyse the economic and environmental aspects of scaling-up this method. To achieve it, a full-scale 40,000 m3·day¿1-wastewater treatment plant influent flow rate was simulated jointly with a membrane contactor plant to evaluate the minimum costs of optimum operating conditions of membrane contactors (pH, feed flow rate and membrane surface). The optimum conditions for treating 600 m3·day¿1 of reject water was found to be 10 pH, 0.08 m3·s¿1 feed flow rate and 10,580 m2 of membrane surface, obtaining a 4% nitrogen ammonia sulphate solution. The results indicated capital (membrane modules and pumps) and operating costs (reagents and energy) of 0.0095 €·m¿3 and a profit of 0.0090 €·m¿3, including energy savings in terms of aeration and sales of the recovered ammonia sulphate, with the added benefit of reducing CO2-eq by 10.3 tons per day., This research was financially supported by the Spanish Ministry of Economy and Competitiveness (MINECO projects CTM2014-54980-C2-1/2-R and CTM2017-86751-C2-1/2-R) with the European Regional Development Fund (ERDF) as well as the Universitat Politecnica de Valencia via a pre-doctoral FPI fellowship to the first author.

International audience; The microbial electrochemical snorkel (MES) is a low-cost, low-maintenance technology that could considerably reduce wastewater treatment costs by reducing the need for aeration. An MES is a single electrode. The lower part, in the anoxic zone of the bioreactor, oxidizes organic matter by transferring electrons to the electrode. The upper part, in the oxic zone, releases the electrons by reducing dissolved oxygen. This study gives new insights into the correlation between the MES potential, the concentration of dissolved oxygen and COD abatement, thus enabling practical rules to be extracted for running the MES in optimal conditions, particularly for adjusting the aeration zone and frequency. Here, aeration promoted the cathodic reaction and increased the MES potential to a maximum (0.0 to 0.1 V/SCE). After aeration stopped, the potential dropped to a minimum (< -0.4 V/SCE). With 26 cm high MESs, sequential aeration at the top was not sufficient to support an effective cathodic zone, while aeration at the bottom was detrimental to the formation of the microbial anode. With MESs 48 cm high and aeration set up in the highest quarter, 30 minutes of aeration every 4.5 hours gave potential variations that were stable for weeks. The MESs continued to oxidize organic matter 30 minutes after the aeration had stopped. In this period, the MESs removed 3 to 6.3 times more COD than the control reactors. Increasing the electrode capacitance is therefore suggested as an effective way to further decrease the aeration cost by decreasing the aeration frequency.

International audience; This paper is a contribution to fasten integration of battery pack innovation in commercial Electric Vehicles (EV) through massive digitalization: a seamless process detailed for battery design, battery safety, and battery management. Selected results of studies carried out on the EV value chain from design to recycling steps are presented, highlighting the importance of seamless integration and holistic state of mind when designing EV. Association between experimental and numerical approaches for efficient innovative EV production is crucial to achieve easy commercialisation. Successful forecasting of aging and thermal runaway evolution from single cell failure at module level using such methods illustrates their great potential. Hardware key counterparts under development are also introduced and give an idea of future architecture of EV battery packs and overall improvement of EV energy efficiency. Finally, a flexible and easily modifiable solution for battery electric vehicle (BEV) that allows rapid and cost-effective integration of future innovation is presented. This paper globally illustrates key breakthroughs gained in the context of the collaborative research project named ‘DEMOBASE’, for DEsign and MOdelling for improved BAttery Safety and Efficiency successfully submitted for funding by the European Commission in response to a 2017 call dedicated to ‘Green Vehicles’ under the EU Horizon 2020 work programme “Smart, green and integrated transport”.

The risk of each nanoform (NF) of the same substance cannot be assumed to be the same, as they may vary in their physicochemical characteristics, exposure and hazard. However, neither can we justify a need for more animal testing and resources to test every NF individually. To reduce the need to test all NFs, (regulatory) information requirements may be fulfilled by grouping approaches. For such grouping be acceptable, it is important to demonstrate similarities in physicochemical properties, toxicokinetic behaviour, and (eco)toxicological behaviour. The GRACIOUS Framework supports the grouping of NFs, by identifying suitable grouping hypotheses that describe the key similarities between different NFs. The Framework then supports the user to gather the evidence required to test these hypotheses and to subsequently assess the similarity of the NFs within the proposed group. The evidence needed to support a hypothesis is gathered by an Integrated Approach to Testing and Assessment (IATA), designed as decision trees constructed of decision nodes. Each decision node asks the questions and provides the methods needed to obtain the most relevant information. This White paper outlines existing and novel methods to assess similarity of the data generated for each decision node, either via a pairwise analysis conducted property-by-property, or by assessing multiple decision nodes simultaneously via a multidimensional analysis. For the pairwise comparison conducted property-by-property we included in this White paper: • A Bayesian model assessment which compares two sets of values using nested sampling. This approach is new in NF grouping. • A Arsinh-Ordered Weighted Average model (Arsinh-OWA) which applies the arsinh transformation to the distance between two NFs, and then rescales the result to the arsinh of a biologically relevant threshold before grouping using OWA based distance. This approach is new in NF grouping. • An x-fold comparison as used in the ECETOC NanoApp. • Euclidean distance, which is a highly established distance metric. The x-fold, Bayesian and Arsinh-OWA distance algorithms performed comparably in the scoring of similarity between NF pairs. The Euclidean distance was also useful, but only with proper data transformation. The x-fold method does not standardize data, and thus produces skewed histograms, but has the advantage that it can be implemented without programming knowhow. A range of multidimensional evaluations, using for example dendrogram clustering approaches, were also investigated. Multidimensional distance metrics were demonstrated to be difficult to use in a regulatory context, but from a scientific perspective were found to offer unexpected insights into the overall similarity of very different materials. In conclusion, for regulatory purposes, a property-by-property evaluation of the data matrix is recommended to substantiate grouping, while the multidimensional approaches are considered to be tools of discovery rather than regulatory methods.

With the development of electronic technologies, electronic devices become smaller, while their power density increases dramatically. The resulting excessive heat requires excellent heat dissipation to ensure great performance of the devices. A good thermal interface material (TIM), with excellent bulk thermal conductivity and proper elastic modulus, which can fill the gap between contact surfaces, is of great importance to improve overall performance of thermal management in the electronic devices. Carbon-based materials, such as carbon nanotubes (CNTs) and graphene (Gr), have attracted great attentions, due to their intrinsic high thermal conductivity. In this paper, carbon-based TIMs are reviewed, as well as the thermal conducting mechanisms and techniques to measure thermal properties for materials. The unique three-dimensional network of 3D-Gr provides not only high thermal conductivity, but also excellent mechanical properties, which makes it more competitive as TIM than CNTs and Gr. Furthermore, there is currently no universal characterization techniques, which are suitable to measure thermal properties of all TIMs. Hence, special attention must be paid to select a proper technique based on the measuring principle, in order to obtain accurate results. An outlook of the future challenges of the thermal interface materials is proposed at the end of the paper.

This paper is the first of three that overview the main mechanisms that drive the microstructure evolution in Fe alloys under irradiation. It focuses on pure a-Fe and compiles the parameters that describe quantitatively the mobility and stability of point-defects and especially their clusters, including possible reactions and criteria to decide when they should react. These parameters are the result of several years of calculations and application in microstructure evolution models. They are mainly collected from the literature and the parameter choice tries to reconcile different sets of values that, while being in general qualitatively similar, are often quantitatively not coincident. A few calculation results are presented here for the first time to support specific approximations concerning defect properties or features. Since calculations cannot cover all possible defect configurations, the definition of these parameters often requires educated guesses to fill knowledge gaps. These guesses are here listed and discussed whenever relevant. This is therefore a “hands-on” paper that: (i) collects in a single report most microstructure evolution parameters that are found in the literature for irradiated a-Fe, including a discussion of the most important mechanisms at play based on current knowledge; (ii) selects a ready-to-use set that can be employed in microstructure evolution models, such as those based on object kinetic Monte Carlo (OKMC) methods. This work also identifies parameters that are needed, but not known, hopefully prompting corresponding calculations in the future. This work has received funding from the Euratom research and training programme 2014-2018 under grant agreement No. 755039 (M4F project). This research also contributes to the Joint Programme on Nuclear Materials of the European Energy Research Alliance (EERA-JPNM).

Bolts and bolted connections are frequently used in civil engineering steel structures. This paper presents a meta study where a few thousand fatigue tests on these elements are evaluated. The evaluation reveals that current specifications in design standards need updating to account for the relevant stress parameter and production methods. This substantially reduces the scatter of the fatigue resistance. The shape and position of the fatigue resistance (S-N) curves also require updating. The results of this study have been implemented in the new revision of European standard EN 1993-1-9. This paper provides the background for the modifications.

Many studies have investigated the potential to reduce the costs of producing renewable hydrogen via water electrolysis by using nonnoble Fe- and Ni-based catalysts. However, Fe- and Ni-based catalysts corrode in alkaline solutions, which makes it unclear whether the catalytic surface components are the pristine catalysts or their transformation products. Further, corrosion limits the catalyst service life. An understanding of this corrosion process is essential to accurately assess the active catalysts during the oxygen evolution reaction (OER) and to design novel catalysts. This paper reviews the corrosion of five types of monometallic Fe- and Ni-based OER catalysts: pure metals, oxides, (oxy)hydroxides, phosphides, and sulfides. A protocol for a rigorous corrosion characterization method is proposed to avoid misleading results during the design of novel catalysts. In light of the corrosion evolution of these catalysts, several key points are also suggested for consideration during the design of novel monometallic Fe- and Ni-based catalysts with high stability and electroconductivity.

The Fukushima nuclear accident in Japan on March 11, 2011, produced large amounts of Cs-polluted soil which must be controlled to prevent the spread of hazardous Cs into the environment. In this paper, the effects of heat treatment on the structure and properties of Cs-containing glass-ceramics, as a simulated nuclear waste form, were systematically investigated. Cesium atoms are chemically bonded in the pollucite structure, and the amorphous phase further encapsulates the pollucite crystals in the glass-ceramics, thus providing an extra protective layer for the immobilized Cs. XRD analysis, Raman and FT-IR studies on the glass-ceramics synergistically indicated that the optimum crystallization temperature for pollucite is around 1000 °C. The pollucite is predominantly the main crystalline phase with a narrow crystal size distribution between 0.5 and 2 μm. Standard leaching test results show that the leaching rate of Cs was very low (3.0 × 10−3 g/(m2·d)). The study offers a practical method for immobilizing Cs in pollucite-base glass-ceramics. Moreover, the experimentally obtained data may provide some important references for converting Cs-polluted soil into pollucite-base glass-ceramics waste form.

With the increasing demand for light weight design in industries such as aerospace and automotive, sheet metallic materials with high strength and low density have been intensively manufactured and widely applied. However, plastic deformation induced surface roughening is an undesirable and a practically unavoidable phenomenon for sheet metallic materials and becomes the subject of great attention in recent years. The evolution of surface roughening plays important roles in the strain limit of the deformation and also significantly influences the product quality and application. This paper provides a comprehensive overview of both experimental and numerical modelling contributions to understand the surface roughening behaviour of sheet metallic materials during various plastic deformation and manufacturing processes. It has been found that roughening of the free surface or necking of the interface is induced by grain scale strain heterogeneity and strongly dependent on the strain the material experienced, strain state and direction, grain size and texture, lubrication, mechanical properties of materials, rolling parameters, etc. By controlling and optimising these parameters, the surface roughening can be optimised for different materials and processing techniques to suit different applications.

Over time, internal combustion engines were profoundly developed becoming more reliable, more economical and less polluting. Even if the current trend is headed towards hybrid and electric vehicles, the development of these engines continues by optimizing its operation with alternative fuels and innovative technologies. Water injection in internal combustion engines is one important way towards engine optimization. This study aims to experimentally determine the effects of direct water injection on the combustion duration of spark-ignition engines. As the thermal processes in internal combustion engines are very complex, the shape of the combustion chamber and other factors, such as the direct water injection timing has a direct influence on the results. This paper explores the potential for such a system in terms of combustion duration showing that the water injection can be beneficial. The concept was applied to a side-valve engine, as this design has a broader potential for injector location and aim.

Lateral friction surfacing, a solid-state deposition process, is a novel friction surfacing technique. In this approach, frictional heat and plastic deformation result in deposition of consumable material from the radial surface of a tool onto a substrate. This paper presents a comprehensive assessment of lateral friction surfacing of AA2011, AA6061, and AA7075 aluminum alloys, with particular focus on the impacts of process parameters on the coating properties. The influence of process variables such as tool rotational speeds, normal applied forces, and type of consumable materials was investigated on the process temperature, physical, and metallurgical characteristics of the deposits using optical microscopy, infrared thermography, scanning electron microscopy, and EDS. This study exhibits that the lateral friction surfacing approach enables the deposition of ultra-thin and smooth layers of different aluminum alloys. Furthermore, the temperature generated in this technique was low enough to avoid plasticizing the substrate and intermixing between the consumable material and substrate, which mitigates the thermal impacts on the grain structures and metallurgical characteristics. The lateral friction surfacing performance of the different alloys can be partially explained by their material properties. High input energy provided by high normal forces and tool rotational speeds may result in failure in the deposition process of materials with lower thermal conductivity and melting point, which emphasizes on limitations for the process parameters during the process.

The process of discovering and developing new materials currently requires considerable effort, time, and expense. Machine learning (ML) algorithms can potentially provide quick and accurate methods for screening new materials. In the present work, the features of the metal organic frameworks (MOFs) as a catalyst for fixing carbon dioxide into cyclic carbonate were extracted to build a data set, which were collected from the experimental results of approximately 100 published papers. Classifiers were trained with the data set with various ML algorithms, including support vector machine (SVM), K-nearest neighbor classification (KNN), decision trees (DT), stochastic gradient descent (SGD), and neural networks (NN), to predict the catalytic performance. The ML models were trained on 80% of the data set and then tested on the remaining 20% to predict the carbon dioxide fixation ability. The trained ML model was extended to explore 1311 hypothetical MOFs, and some structures displayed a strong catalytic ability. Finally, the six best metal ions (Mn, V, Cu, Ni, Zr and Y) and four best ligands (tactmb, tdcbpp, TCPP, H3L) were determined. These six metals and four ligands could be combined into 24 MOFs, which are strongly potential catalysts for carbon dioxide fixation. Using machine learning methods can speed up the screening of materials, and this methodology is promising for application not only to MOFs as catalysts but also in many other materials science projects.

Solar energy is the leading thermal source from the sun, with huge use of technology such as photovoltaic cells, solar power plates, photovoltaic lighting, and solar pumping water. The current effort deals with solar energy analysis and a technique to enhance solar aircraft effectiveness by using solar and nanotechnological energy. The work is based on the investigation of thermal transfer by utilizing hybrid nanofluid past an inside solar wings parabolic trough solar collector (PTSC) to rich the studies of the solar aircraft wings. The thermal source is titled solar radiative flow. For various properties such as porous media, Cattaneo Christov heat flux, viscous dissipation, play heating and thermal energy flow, the heat transfer efficiency of the wings is verified. In the case of the tangent hyperbolic fluid, the entropy generation analysis was applied. The modeled energy and momentum equations were managed using the well-established numerical plan known as the Keller box process. This paper is made up of double-different kinds of nano solid particles, Cu (copper) and ZrO2 (zirconium dioxide) in EG (ethylene glycol) as standard fluid. Various control parameters are discussed and shown in figures and tables for velocity, shear stress, temperature outlines, frictional factor, and Nusselt number. The efficiency in the aircraft wings in the case of thermal radiation amplification and variable thermal conduction parameters is seen to be improved in terms of thermal transfer. In comparison to the traditional nanofluid, hybrid nanofluid is the ideal source of heat transfer. The thermal efficiency of ZrO2–Cu/EG compared to Cu-EG decreases to a low of 2.6% and peaks to 3.6%.

In this paper, sulfur doped g-C3N4 (S-g-C3N4) was successfully prepared at 500 °C for 3 h via a modified molten salt method using dicyandiamide as the main raw material, trithiocyanuric acid as the sulfur source and LiBr KCl as the reaction medium. The as-prepared S CN5.0% sample (the mass ratio of trithiocyanuric acid to dicyandiamide was 5.0%) composed of irregular flakes showed a band gap of 1.83 eV, which was narrower than that (2.55 eV) of pristine g-C3N4. The S CN5.0% sample also exhibited an outstanding absorption capacity of visible light. Moreover, the photodegradation rate toward methylene blue and tetracycline were respectively 10 and 20 times as high as that of bulk g-C3N4 prepared by conventional heating methods, confirming its superior photocatalytic performance. These results can be attributed to that the replacement of lattice nitrogen with sulfur atom tuned the electronic structure of g-C3N4, improved the absorption of visible light, optimized the separation of photogenerated electron-hole pairs, and consequently enhanced the photocatalytic activity of g-C3N4. Moreover, the trapping experiments implied that hole (h+) and superoxide radical (·O2−) were the main active species in the process of photodegradation.

This work assesses the possibility/feasibility of utilizing the CFD to predict water-air separation in a mini-manifold at ambient conditions. The manifold consists of a header with three reduced T-junctions. A combination of the manifold size and the operating parameters yields a computationally demanding surface tension dominant flow. A computational model of separation is based on the interface tracking technique and the FVM framework. The results are validated against the experiment. Findings show that the separation can be successfully predicted, even under such conditions. Analysis of computational cost revealed that the long computational time is the only limiting factor for regular CFD use in such applications. The paper's novelty is in the successful prediction of phase separation. Such an approach requires flow pattern prediction capabilities in the straight parts of the manifold and physically sound interface split prediction at the T-junctions that have not been explored previously in such a way.

The paper deals with the synthesis of Guar gum and ethyl acrylate (GG-EEA) composite. The synthesized natural polysaccharide composite was used as a corrosion inhibitor to reduce hydrogen evolution and P110 steel corrosion protection in 15% HCl (Hydrochloric acid). The primary corrosion techniques like weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) was used to analyze the corrosion inhibition process. The PDP proposed that GG-EEA composite is a mixed-type corrosion inhibitor and inhibits corrosion by blocking the active sites presenting over the metal surface. The corrosion inhibition performance of GG alone is 77.5%, and that of GG-EEA is 92.3% at 500 mg/L. The adsorption of GG-EEA onto P110 steel is spontaneous and mixed type, i.e., both physical and chemical. The conformation of GG-EEA molecule adsorption was done using a scanning electron microscope (SEM), Energy dispersive x-ray spectroscopy (EDX), Atomic force microscopy (AFM), and X-ray photoelectron spectroscopy studies. Density functional theory (DFT) analysis was done to explore the active sites over the inhibitor in metal-inhibitor interaction. Molecular dynamic simulation (MD) simulations study reveals that GG-EEA has more adsorption capacity than GG alone.

This paper presents a 2D transient heat transfer model, which has been developed using finite difference method for composites made by AFP process with a hot gas torch. The model includes non-linear distributions for the hot gas/air temperature and convection coefficients in the vicinity of composite, which are essential to increase the accuracy of the model. It is necessary not to just obtain the accurate maximum temperature of composite, but more importantly, the thermal gradients in the composite laminate. These thermal gradients have strong influence on the development of residual stresses and deformation in thermoplastic laminates made by AFP. In addition, the temperature dependencies of the material properties and inter-layer thermal contact resistance have been taken into account. Comparison of the experimental and theoretical results indicates how the accuracy of model increases by considering the above mentioned aspects.

The rapidly increasing penetration of distributed energy resources (DERs) calls for a hierarchical framework where aggregating entities handle the energy management decisions of small DERs and represent these DERs upstream. These energy management decisions are typically envisaged to be made via market-based frameworks, aspiring the so-called Local Electricity Markets (LEMs). A rich literature of studies models such LEMs adopting various modeling assumptions and proposes various Market Mechanisms towards making dispatch and pricing decisions. In this paper, we make a systematic presentation of a LEM formulation, elaborating on the cornerstone attributes of the market model, i.e. the Market Scope, the Modeling Assumptions, the Market Objective, and the Market Mechanism. We discuss the different market model choices and their implications and then focus on the prevailing approaches of Market Mechanisms. Finally, we classify the relevant literature based on the market model that it adopts and the proposed Market Mechanism, visualize the results and also discuss patterns and trends.

Nigeria is second to South Africa with the highest reported cases of COVID-19 in sub-Saharan Africa. In this paper, we employ an SEIR-based compartmental model to study and analyze the transmission dynamics of SARS-CoV-2 outbreaks in Nigeria. The model incorporates different group of populations (that is, high- and- moderate risk populations) and is use to investigate the influence on each population on the overall transmission dynamics.The model, which is fitted well to the data, is qualitatively analyzed to evaluate the impacts of different schemes for controlstrategies. Mathematical analysis reveals that the model has two equilibria; i.e., disease-free equilibrium (DFE) which is local asymptotic stability (LAS) if the basic reproduction number ( R 0 ) is less than 1; and unstable for R 0 > 1 , and an endemic equilibrium (EE) which is globally asymptotic stability (LAS) whenever R 0 > 1 . Furthermore, we find that the model undergoes a phenomenon of backward bifurcation (BB, a coexistence of stable DFE and stable EE even if the R 0 1 ). We employ Partial Rank Correlation coefficients (PRCCs) for sensitivity analyses to evaluate the model’s parameters. Our results highlight that proper surveillance, especially movement of individuals from high risk to moderate risk population, testing, as well as imposition of other NPIs measures are vital strategies for mitigating the COVID-19 epidemic in Nigeria. Besides, in the absence of an exact solution for the proposed model, we solve the model with the well-known ODE45 numerical solver and the effective numerical schemes such as Euler (EM), Runge–Kutta of order 2 (RK-2), and Runge–Kutta of order 4 (RK-4) in order to establish approximate solutions and to show the physical features of the model. It has been shown that these numerical schemes are very effective and efficient to establish superb approximate solutions for differential equations.

This paper is devoted to addressings the fairly interesting soliton solutions for the time fractional combined Korteweg-de Vries-modified Korteweg-de Vries equation (KdV–mKdV equation) and modified Burgers-KdV equation. The unified method along with conformable, Beta and local M-derivative are used to construct the general structure of solitary wave soliton solutions. The method allows us to find solutions in both polynomial and rational forms. Further, the comparison of solutions are given out through 3D and 2D-plots to expose the impact of fractional parameter on the obtained solutions. The reported solutions are novel and have not been discussed in the literature.

In light of the Paris Agreement, road-freight represents a critically difficult-to-abate sector. In order to meet the ambitious European transport sector emissions reduction targets, a rapid transition to zero-carbon road-freight is necessary. However, limited policy assessments indicate where and how to appropriately intervene in this sector. To support policy-makers in accelerating the zero-carbon road-freight transition, this paper examines the relative cost competitiveness between commercial vehicles of varying alternative drive-technologies through a total cost of ownership (TCO) assessment. We identify key parameters that, when targeted, enable the uptake of these more sustainable niche technologies. The assessment is based on a newly compiled database of cost parameters which were triangulated through expert interviews. The results show that cost competitiveness for low- or zero-emission niche technologies in certain application segments and European countries is exhibited already today. In particular, we find battery electric vehicles to show great promise in the light- and medium-duty segments, but also in the heavy-duty long-haul segments in countries that have enacted targeted policy measures. Three TCO parameters drive this competitiveness: tolls, fuel costs, and CAPEX subsidies. Based on our analysis, we propose that policy-makers target OPEX before CAPEX parameters as well utilize a mix of policy interventions to ensure greater reach, increased efficiency, and increased policy flexibility. ISSN:0306-2619 ISSN:1872-9118

This paper presents reports on the preparation of a multifunctional coating system, CrNx, with temperature sensing capability. A systematic study of the thermo-resistive effect of chromium nitride (CrNx) thin films with a negative temperature coefficient of resistance (TCR) has been carried out. The CrNx nanostructures were grown by reactive magnetron sputtering under distinct Ar+N2 conditions. To confer a zigzag columnar morphology to the CrNx we explored the oblique angle deposition technique. The structural properties have been studied through X-ray diffraction and Scanning Electron Microscopy. The thermo-resistive response was evaluated by measuring the electrical resistivity as a function of temperature by the twopoint method. The results observed for the CrNx films produced with N2 flux between 4 and 8 sccm present an stable and negative TCR. Values of -9.1710-4 , -5.3110-3 , and -1.47610-2 were observed for the films grown with 4, 6, and 8 sccm, respectively. The grain-boundary was used to theoretically describe our results. The results open new technological possibilities for the application of CrNx coatings for esistive temperature detector (RTD) systems., The authors thank the Portuguese Foundation for Science and Technology (FCT) for the strategic funding UID/FIS/04650/2020. A. Ferreira thanks the FCT for the contract under the Stimulus of Scientific Employment (CTTI-31/18 - CF (2) junior researcher contract) . M. A. Correa thanks the CNPq and CAPES. The authors acknowledge funding by the Basque Government Industry and Education Departments under the ELKARTEK and PIBA (PIBA-2018-06) programs, respectively, and to European Regional Development Fund under the Operational Program Cdompetitiveness and InternationalizationdResearch and Development (R&D) and Innovation to SMEs - R&D Individuals Projects, grant agreement no 038397.

An activated carbon was produced from paper mill sludge (AC-P) and functionalized with thiol groups (AC-MPTMS) for the adsorptive removal of the antibiotic sulfamethoxazole (SMX) from buffered solutions prepared in ultrapure water (pH 8) and real wastewater samples. The physicochemical properties of the two materials (AC-P and AC-MPTMS) showed differences mainly in specific surface area (SBET), in the type of oxygen functional groups and in the relative percentage of sulphur groups. The adsorption results showed a decrease in the Langmuir adsorption capacity (qm) upon an increase on temperature (15, 25 and 35 °C), varying between 113 ± 7 and 42.5 ± 0.6 mg g−1 for AC-P and between 140 ± 20 and 28.0 ± 1.5 mg g−1 for AC-MPTMS. Pseudo-second order model presented the best fit for the kinetic studies, with rate constants (k2) increasing with temperature and varying from 0.005 ± 0.002 to 0.013 ± 0.004 g mg−1 min−1 for AC-P and from 0.006 ± 0.002 to 0.03 ± 0.01 g mg−1 min−1 for AC-MPTMS. Both adsorbents showed very similar thermodynamic parameters, with the adsorption process being spontaneous (−26 kJ mol−1 ≤ ΔG° ≤ −40 kJ mol−1), endothermic (69 kJ mol−1 ≤ ΔH° ≤ 78 kJ mol−1), and entropically favorable (356 ≤ ΔS° ≤ 365 J mol−1 K−1). The performance of AC-MPTMS in the removal of SMX was tested in wastewater, where the material displayed lower SMX adsorption velocity and capacity than in buffered aqueous solution (pH 8) due to competitive matrix effects., Thanks are due to FCT/MCTES for the financial support to CESAM (UIDP/50017/2020+ UIDB/50017/2020) and CICECO-Aveiro Institute of Materials, (UIDB/50011/2020 & UIDP/50011/2020), through national funds. Guilaine Jaria thanks her PhD grant (SFRH/BD/138388/2018) supported by national funds and FSE through Fundação para a Ciência e a Tecnologia (FCT), POCH (Programa Operacional Capital Humano) and European Union. Marta Otero, Paula Ferreira and Sérgio Santos thank FCT for the Investigator Program (IF/00314/2015, IF/00300/2015 and IF/00973/2014, respectively). Vânia Calisto is thankful to FCT for Scientific Employment Stimulus (CEECIND/00007/2017). María V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) by the Spanish Government, co-financed by the European Social Fund (ESF). The authors thank to the project RemPharm (PTDC/AAG-TEC/1762/2014) funded by FCT, I.P., through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Milton Fontes and workers of Aveiro's WWTP (Águas do Centro Litoral) are gratefully acknowledged for assistance on the effluent sampling campaigns.

Field-effect transistor (FET) sensors are attractive potentiometric (bio)chemical measurement devices because of their fast response, low output impedance, and potential for miniaturization in standard integrated circuit manufacturing technologies. Yet the wide adoption of these sensors for real-world applications is still limited, mainly due to temporal drift and cross-sensitivities that introduce considerable error in the measurements. In this paper, we demonstrate that such non-idealities can be corrected by joint use of an array of FET sensors – selective to target and major interfering ions – with machine learning (ML) methods in order to accurately predict ion concentrations continuously and in the field. We studied the predictive performance of linear regression (LR), support vector regression (SVR), and state-of-art deep neural networks (DNNs) when monitoring pH from combinatorial H+, Na+, and K+ion-sensitive FET (ISFET) sequences of readings collected over a period of 90 consecutive days in real water quality assessment conditions. The proposed ML algorithms were trained against reference online measurements obtained from a commercial pH sensor. Results show a greater capability of DNNs to provide precise pH monitoring for longer than a week, achieving a relative root-mean-square error reduction of 73% over standard two-point sensor calibration methods., The authors acknowledge funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 747848 and the SNSF-Sinergia WeCare project (No.CRSII5_177255).

The determination of the optical band gap energy ( E g ) is important for optimization of the generation of electron/hole pairs in semiconductor materials under illumination. For this purpose, the classical theory proposed by Kubelka and Munk (K-M) has been largely employed for the study of amorphous and polycrystalline materials. In this paper, the authors demonstrate, step by step, how to use the K-M function and apply it thoroughly to the determination of the E g of TiO2 semiconductor powder (pressed at different thicknesses) from diffuse reflectance spectroscopy (DRS) measurements. For the sample thicknesses 1–4 mm, E g values of 3.12–3.14 eV were obtained. With this work it is envisaged a clarification to the procedure of determination of the E g from the K-M theory and DRS data, since some drawbacks, and misconceptions have been identified in the recent literature. In particular, the widely used practice of determining the E g of a material directly from the K-M function is found to be inadequate.

Ceramics long history in biomedical field is related to their high biocompatibility and mechanical properties. Precisely, for joint replacements, wear resistance is fundamental, so advanced ceramics as alumina and zirconia are preferred. Developments in ceramic additive manufacturing allow for dense ceramic parts with improved mechanical properties and shape accuracy. This paper focuses on the tribological analysis of stereolithography-manufactured components for orthopaedics. Alumina, yttria-stabilised zirconia, 10 and 20 wt% zirconia toughened alumina (ZTA) samples were analysed. The effect of surface finishing, microstructure and microhardness on wear was considered. Printing orientation does not significantly impact microhardness, wettability, and microporosity. However, some printing artefacts as the staircase effect were observed on spherical surfaces. Zirconia system presented high wear rates and friction coefficient, while alumina system showed more acceptable and stable values, with the formation of a self-mated tribofilm. ZTA composites presented the lowest wear volume and better mechanical and surface properties in general.

International audience; The present paper studies the material removal evolution, during Plasma Electrolytic Polishing (PeP), on model roughnesses prepared on 1050 aluminum alloy (AA), i.e. a quasi-pure aluminum, used as a model substrate. The results obtained in this study confirm the significance of the applied voltage on aluminum removal. In particular, the minimal voltage to be applied to generate the plasma is seen to be above 230 V. Meanwhile, at a higher voltage of 300 V, high quality polishing is obtained. Using this technique, rolling streaks are eliminated rapidly without the workpiece's geometry being adversely affected. Finally, roughness evolution was accurately studied on a series of samples with various well-defined levels of model roughness generated by microindentation. The study shows that only a few minutes of processing are needed to obtain a significant reduction in roughness, even representing up to 70%. Results show also that roughness valleys do not undergo material removal at all as long as peak to valley height remains high enough. As the process goes on, roughness (i.e. mainly peaks) is reduced and valleys become submitted to material removal as well.

Highlights • Shale samples were exposed to slick water under the condition of 120 °C and 20 MPa within 30–90 days. • Microindentation was conducted to probe the distance-dependent, gradient alteration to shale mechanical properties. • The average rate of softening advancement was estimated as 0.13 mm/day. • The dissolution of carbonate minerals, pyrite oxidation and clay mineral osmotic swelling determine the shale softening. The shale softening behavior caused by hydrofracturing fluid is of great influence for the fracture conductivity and ultimate recovery of oil and gas from reservoir formations. This paper presents an experimental study on the characterization of a shale after being softened by the coupled thermo-hydro-mechanical-chemical (THMC) treatments that simulate the high-temperature and high-pressure rock-fluid interactions occurring in deep reservoirs during and after hydraulic fracturing. Microindentation tests were conducted to characterize the degradation degree and rate of mechanical properties of THMC-treated samples, and X-ray diffraction (XRD), scanning electron microscope (SEM), and micro-computed tomography (micro-CT) were carried out to analyze compositional and microstructural alterations of samples prior to and after THMC treatment. The results show that Young's modulus, hardness, and fracture toughness degrade significantly upon THMC treatment, and the average softening rate was estimated as 0.13 mm/day. The degradation of mechanical properties of the softened zones is primarily owing to the porous microstructure and crack propagation, resulting from the dissolution of carbonates, pyrite oxidation and the clay mineral osmotic swelling. These findings can provide a good insight of shale-fracturing fluid interactions, phenomenological behavior of shale softening that take place in deep reservoirs at elevated temperatures and pressures, and shed lights on the design, and operation of shale gas exploration.

The M4F project brings together the fusion and fission materials communities working on the prediction of radiation damage production and evolution and their effects on the mechanical behaviour of irradiated ferritic/martensitic (F/M) steels. It is a multidisciplinary project in which several different experimental and computational materials science tools are integrated to understand and model the complex phenomena associated with the formation and evolution of irradiation induced defects and their effects on the macroscopic behaviour of the target materials. In particular the project focuses on two specific aspects: (1) To develop physical understanding and predictive models of the origin and consequences of localised deformation under irradiation in F/M steels; (2) To develop good practices and possibly advance towards the definition of protocols for the use of ion irradiation as a tool to evaluate radiation effects on materials. Nineteen modelling codes across different scales are being used and developed and an experimental validation programme based on the examination of materials irradiated with neutrons and ions is being carried out. The project enters now its 4th year and is close to delivering high-quality results. This paper overviews the work performed so far within the project, highlighting its impact for fission and fusion materials science. Peer Reviewed L. Malerba a,*, M.J. Caturla b, E. Gaganidze c, C. Kaden d, M.J. Konstantinovi´c e, P. Olsson f, C. Robertson g, D. Rodney h, A.M. Ruiz-Moreno i, M. Serrano a, J. Aktaa c, N. Anento j, S. Austin i, A. Bakaev e, J.P. Balbuena b, F. Bergner d, F. Boioli k, M. Boleininger l, G. Bonny e, N. Castin e, J.B. J. Chapman l, P. Chekhonin d, M. Clozel m, B. Devincre k, L. Dupuy g, G. Diego a, S.L. Dudarev l, C.-C. Fu g, R. Gatti k, L. G´el´ebart g, B. G´omez-Ferrer n, D. Gonçalves g, C. Guerrero a, P.M. Gueye n, P. H¨ahner i, S.P. Hannula o, Q. Hayat p, M. Hern´andez-Mayoral a, J. Jagielski m, N. Jennett p, F. Jim´enez a, G. Kapoor d, A. Kraych h, T. Khvan e,q, L. Kurpaska m, A. Kuronen r, N. Kvashin j, O. Libera s, P.-W. Ma l, T. Manninen o, M.-C. Marinica g, S. Merino a, E. Meslin g, F. Mompiou t, F. Mota a, H. Namburi s, C.J. Ortiz a, C. Pareige n, M. Prester u, R.R. Rajakrishnan t, M. Sauzay g, A. Serra j, I. Simonovski i, F. Soisson g, P. Sp¨atig v, D. Tanguy h, D. Terentyev e, M. Trebala o, M. Trochet g, A. Ulbricht d, M.Vallet g, K. Vogel d, T. Yalcinkaya w, J. Zhao r a Centro de Investigaciones Energ´eticas, Medioambientales y Tecnol´ogicas (CIEMAT), Madrid, Spain b Universidad de Alicante, San Vicente del Raspeig, Spain c Karlsruher Institut für Technologie (KIT), Karlsruhe, Germany d Helmholtz-Zentrum Dresden-Rossendorf Ev (HZDR), Rossendorf, Germany e Studiecentrum voor Kernenergie / Centre d’´Etude de l’´Energie Nucl´eaire (SCK CEN), Mol, Belgium f KTH Royal Institute of Technology, Stockholm, Sweden g Universit´e Paris-Saclay, Commissariat `a l’´Energie Atomique et aux ´Energies Alternatives (CEA), Gif-sur-Yvette, France h Institut Lumi`ere Mati`ere (ILM), Centre National de la Recherche Scientifique, Lyon, France i Joint Research Centre (JRC)- European Commission, Petten, the Netherlands j Universitat Polit`ecnica de Catalunya, Barcelona, Spain k Laboratoire d’Etude des Microstructures (LEM), Centre National de la Recherche Scientifique, Chˆatillon, France l United Kingdom Atomic Energy Authority (UKAEA), Culham, UK m Narodowe Centrum Badan Jadrowych (NCBJ), Swierk, Poland n Normandie Univ, UNIROUEN, INSA Rouen, CNRS, Groupe de Physique des Mat´eriaux, 76000 Rouen, France o Aalto University, Espoo, Finland p Coventry University, UK q Universit´e de Li`ege, Belgium r Helsingin Yliopisto, Helsinki, Finland s Centrum Vyzkumu ˇReˇz S.R.O. (CVR), ˇReˇz, Czech Republic t Centre pour l’´Elaboration Elaboration de Mat´eriaux et pour l’´Etude des Structures (CEMES), Centre National de la Recherche Scientifique, Toulouse, France u Institut za Fiziku, Zagreb, Croatia v Paul Scherrer Institut (PSI), Villingen, Switzerland w Middle East Technical University (METU), Ankara, Turkey

As a chemically resistant hard substrate with surface-mounted metal pads, Printed Circuit Boards (PCBs) have the potential to be utilized as substrates for electrochemical applications such as electrochemical microfluidic devices. Compared with regular electrochemical substrates made with glass slides or filter papers, PCB-based substrates have electrode pads with customized size, shape and position, and more wiring layers. Previous works have shown that the PCB-based electrochemical devices can be used as biosensors, electrochemical impedance cytometers, and electrochemical imaging platforms, while their workability as a platform for electrocatalysis has not yet been presented. This work presents a method to develop PCBs into electrochemical substrates for alcohol electrocatalysis and internal reference electrodes. The copper pads were pretreated and electrodeposited with nickel (Ni), silver (Ag), palladium (Pd), and platinum (Pt) for various electrocatalytic purposes. To show the ability of making PCB-based electrochemical devices, two types of PCB-based reference electrodes were made.

Integrating sector coupling technologies into Hydrogen (H2) based hybrid renewable energy systems (HRES) is becoming a promising way to create energy prosumers, despite the very little research work being done in this largely unexplored field. In this paper, a sector coupling strategy (building and transportation) is developed and applied to a grid-connected PV/battery/H2 HRES, to maximise self-sufficiency for a University campus and to produce power and H2 for driving electric tram in Ouargla, Algeria. A multi-objective size optimization problem is solved as a single objective problem using the e-constraint method, in which the cost of energy (COE) is defined as the main objective function to be minimized, while both loss of power supply probability (LPSP) and non-renewable usage (NRU) are defined as constraints. Particle swarm optimization and HOMER software are then employed for simulation and optimization purposes. Prior to the two scenarios investigated, a sensitivity study is performed to determine the effects of H2 demand by tram and NRU on the techno-economic feasibility of the proposed system, followed by a new reliability factor introduced in the optimization, namely loss of H2 supply probability (LHSP). The results of the first scenario show that by setting NRUmax = 100%, the system without H2 provides the best solution with COE of 0.016 $/kWh that reaches grid parity and has 13% NRU. However, by setting NRUmax = 1% in the second scenario, an optimized configuration consisting of grid/PV/Electrolyzer/Fuel cell/Storage tank is obtained, which has 0% NRU and COE of 0.1 $/kWh. In the second scenario, it is also observed that an increased number of trams (i.e. increased H2 demands) causes a significant reduction in LHSP, COE, NRU and CO2 emissions. It is thus concluded that the grid/PV combination is the optimal choice for the studied system when considering economic aspects. However, taking into account the growing requirements of future energy systems, grid-connected PV with H2 will be the best solution.

Compared with the use of other types of sensors, there are significant advantages in making measurements of low speed gas flows by using a fiber-optic ‘hot-wire’ sensor. Measurements of this type using intrinsically safe fiber optic technology play an important role in industry, especially in coal mine gas clearance, roadway ventilation and fire safety warning. However, the ‘line-diameter ratio’ of the fiber-optic ‘hot-wire’ wind speed sensor described in previous work is far smaller than that for the traditional electronic hot-wire sensor and this requires investigation and optimization. To do that necessitates considering the combined influence of factors such as forced convection, natural convection, radiation heat transfer and heat conduction on the operation of the sensor probe, especially on the heat transfer between the sensor element and the base, when analyzing the performance of the fiber-optic ‘hot-wire’ gas flow speed sensor and in modelling its characteristics. Based on the results of the model of electronic hot-wire sensor created, this paper presents a method to improve and indeed further enhance the performance of the sensor, having a focus on the proportion of convective heat transfer to the total energy dissipation under different ambient and different wind speed conditions, as well as the influence of different ambient temperatures on the sensor probe. The results of the numerical simulation and the experimental verification carried out show that the measurement error was less than ±0.2 m/s, when used within the gas flow speed range of 0−6 m/s. Compared with the situations before the compensation was applied, the measurement error in the use of the sensor is reduced and the sensor performance significantly improved.

Heat assisted-forming processes are essential for Ti6Al4V sheet metal forming due to the poor formability of this alloy at room temperature. Although there exist works on the stress-strain response at high temperature, there is a lack of data in the literature on the yield criteria. The present paper presents an efficient experimental methodology to determine significant stress states at high temperature. Both plane strain data and compressive anisotropy values at high temperature allowed obtaining a more complete definition of the mechanical behavior of the Ti6Al4V, being the novel contribution of this research. Yield loci up to 900 °C were built according to different yield criteria that are fitted to the experimental data. Thus, Barlat1989 and CPB2006 were selected as the most suitable yield criteria to predict Ti6Al4V behavior. These criteria were extended to contemplate the anisotropy evolution under a wide range of working conditions. The formulated extended criteria for the entire range of conditions were close to the equivalent traditional ones applied to only a particular condition, which demonstrates the advanced made in the comprehensive modeling of Ti6Al4V alloy for all conditions applied in forming industries.

The paper describes Electromagnetic Ring Expansion Tests (ERET) performed on Laser Melting Powder Bed Fusion (LPBF) Inconel 718 stress relieved test pieces, to establish the effect of a randomly dispersed spherically voided microstructure on tensile ductility, fracture, and fragmentation at high strain rate (10-3 < e < 104 s-1). An empirical model to predict porosity type and growth rates as a function of laser energy density was established, to select the LPBF process parameters to fabricate test pieces under stable conduction and keyhole melting. The size, shape, distribution of macro and keyhole pores in the test pieces obtained for ERET testing were characterised. At high strain rate the number of ring fragments for the highest porosity doubled, accompanied by a reduction in true strain at maximum uniform elongation and fracture strain. The trend for reducing fracture strain with increasing porosity at high strain rate was described by a decaying power law. Overall, there was a significant positive strain rate effect on tensile ductility at lower porosities attributed strain rate hardening (Hart, 1967) [1]. Fracture surfaces containing the highest porosity identified four different void coalescence mechanisms that helped explain the influence of larger pores on the stress state in the alloy. The AM of IN718 and tensile testing was funded by the UoD, College of Science and Engineering Research Excellence Framework (REF) funding for the Director of IISE (P. Wood) and AM Researcher (U. Gunputh). The support of G. Williams for IN718 sample preparation and M. Pawlik for tensile testing is acknowledged. A. Rusinek acknowledges the program UC3M-Santander Chair of Excellence in additive manufacturing. The expanding ring tests investigations were funded by the Polish Ministry of Science and Higher Education, Centre for Research and Development under research grant No. TECHMATSTRATEG2/410049/12/NCBR/2019.

In this paper we report the morphology and the microstructural properties of thick [1 1 1]-oriented 3C-SiC films epitaxially grown on T-shaped Si micropillars. This compliant substrate was designed to release the stress developed in 3C-SiC grown on Si, due to the lattice mismatch and the different thermal expansion coefficients between 3C-SiC and Si. In this way it was possible to have 3C-SiC films as thick as 10 and 16 μm, with small bowing and no cracks. Our study relies on the use of an Electron Microscopy approach and elucidates the structure of the crystallographic defects across the 3C-SiC film, such as stacking faults (SFs), nano-twins and grain boundaries (GBs). After examination of the morphological and structural characteristics of the Si micropillar array, we analyzed the crystallographic properties of the thin 3C-SiC deposit on the Si micropillar sidewalls, since it may have an impact on the upper film. To assess the crystal quality of the 3C-SiC film, we quantified the SF density at the 3C-SiC surface, even estimating semi-quantitatively the depletion of SFs at much larger thickness. Hence, we analyzed the regions where 3C-SiC microcrystals grown on neighboring Si micropillars coalesce and form a continuous layer. We found that the coalescence between adjacent 3C-SiC microcrystals produces twinned regions, which terminate with the formation of GBs. We noticed that SFs may annihilate at the GBs, leading to the SF reduction across the 3C-SiC film. Finally, we observed the closure of the GBs inside the 3C-SiC film, thus improving the crystal quality of its surface. This work endorses the use of Si micropillars as compliant substrate to grow thick [1 1 1]-oriented 3C-SiC films with good crystal quality and is preliminary to the exploitation of 3C-SiC for high performing microelectronic devices.

This paper presents a comprehensive study of the microstructure-property relationships in Ta and stainless or carbon steel composites, fabricated by explosive welding using Cu interlayer. Employing scanning (SEM) and transmission (TEM) electron microscopy and X-ray synchrotron diffraction, a complex microstructure of interfacial layers was examined. Particular attention was placed on the description of the phase transformation mechanisms in the reaction regions, and the competition between the strain-hardening and softening processes in parent sheets. SEM and TEM analyses showed that Cu and Ta nanoparticles, and small dendrites, dominated the reaction regions near the Ta/Cu interfaces, whereas the nano-grained phases having more complex chemical compositions were identified near the Cu/steel interfaces. SEM orientation mapping revealed that the interfacial layers of the parent sheets underwent severe plastic deformation as a result of dislocation slip, twinning, and shear banding. Such heavily deformed areas can easily undergo recovery and recrystallization already during clad processing. In consistence with these findings, the micro-hardness values of the welded sheets increased as the joining interface approached, except for the layers directly adhering to large reaction regions, where a decrease in micro-hardness was observed. However, the solidified melt regions were essentially softer than the strain-hardened layers of both steels. Based on experimental results a new explanation for the reaction region formation was proposed and a significant modification of the description of the interfacial microstructure of parent sheets was done. Finally, the effect of microstructural changes on the clads properties was discussed.

The use of magnetron sputtering for deposition of the metal electrode in perovskite solar cells has been limited because of the damage to the organic hole transport layer by high kinetic energy particles during the sputtering process. In this paper, a systematic investigation into the effect of sputtering power, argon flow rate, sputtering duration, and argon pressure on the performance of the perovskite cells was conducted. The results of this work show that high power conversion efficiency of 18.35% was obtained for solution-processed, air-fabricated perovskite solar cells with Ag contact prepared using magnetron sputtering. The devices also exhibit an excellent short-current density of 22.56 mA/cm2, an open-circuit voltage of 1.10 V and a fill factor of 73.7%. The investigation reveals that sputtering power is the most critical factor that needs to be carefully controlled to minimise the damage to the hole transport layer. This study demonstrates that highly efficient perovskite solar cells can be fabricated using magnetron sputtering if the sputtering parameters are optimised.

Made available in DSpace on 2021-06-25T11:18:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-09-01 In this paper, the analog properties of advanced GaN/AlGaN High-Electron-Mobility Transistors (HEMTs) are studied as a function of temperature (T). The drain current, the threshold voltage, the transconductance and the output conductance are experimentally investigated under saturation operation. Moreover, important figures of merit for the analog performance, such as transconductance-over-drain current, Early voltage and intrinsic voltage gain are analyzed for different channel lengths in the temperature range of 25 °C till 200 °C. The results indicate that due to change in the Fermi potential, the analog parameters reduce with increasing T. Furthermore, the performance increase for longer channel devices is correlated directly with the lower drain electric field penetration. São Paulo State University (UNESP) Institute of Science and Technology, Av. 3 de Março, n. 511 imec, Kapeldreef 75 Vrije Universiteit Brussels, Pleinlaan 2 São Paulo State University (UNESP) Institute of Science and Technology, Av. 3 de Março, n. 511

Fischer-Tropsch synthesis provides an important opportunity for utilization of biomass and plastic waste. Iron catalysts are the catalysts of choice for light olefin synthesis using Fischer-Tropsch reaction. In this paper, we investigate strong promoting effects of antimony and tin on the catalytic performance of silica supported iron Fischer-Tropsch catalysts using a combination of advanced and in-situ techniques. The catalyst doping with these elements added via impregnation results in a major increase in the reaction rate and much better catalyst stability. No enhancement of iron dispersion was observed after the promotion, while somewhat higher extent of iron carbidization was observed in the antimony promoted catalysts. Iron-bismuth bimetallic nanoparticles are detected by several techniques. In the working catalysts, the promoters are located in close proximity to the iron nanoparticles. The promotion leads to the 7–10 times increase in the intrinsic activity of iron surface sites due to their interaction with the promoters. 292

Propellants are the main energy source in the internal ballistic process. The use of 3D printing has promised to produce propellants with complex geometries. However, due to the degraded energy properties of propellants using an inert binder, there is a critical need to develop a printable energetic resin. In this paper, a novel energetic acrylate-terminated poly–3–nitratomethyl–3–methyloxetane (APNIMMO) oligomer was prepared and characterized. The performance of a new composite propellant composed of APNIMMO and CL-20 (Hexanitrohexaazaisowurtzitane Dodecane) was also demonstrated. The new energetic printable resin and its composites are suitable for stereolithography (SLA) 3D printing, offering not only an improved thermodynamic energy, but also a substantially improved burn rate. Compared with the inert binder, the energetic binder offers the possibility to improve the thermodynamic energy by 15% and the burn rate at 100 MPa by 480% for 3D printed propellants.

This paper introduces new composite architectures using carbon and glass fibre-reinforced epoxy prepregs to achieve gradual failure under bending. The concept is based on a technique developed by the authors to design hybrid composites with gradual failure in tension combined with beam theory to identify and control the failure sequence of the plies in the layups. Two layups are designed based on standard ply thickness S-Glass and hybrid sub-laminates made out of intermediate and high modulus thin-ply carbon prepregs. The layups are tested under 4-point bending loading where a gradual failure alongside high values of flexural displacement are achieved. No catastrophic failure is observed throughout the whole loading process. The gradual layer-by-layer failure of the surface layers on the tensile side produces a brush-like appearance. Microscopy observations from interrupted tests verified fragmentation of the high-modulus carbon layer followed by gradual failure of the intermediate modulus carbon layer and delamination on the tensile side, as well as stable shear cracks of the high-modulus carbon layer on the compression side.

Highlights • Researchers with non-engineering background treat CFD too simplistic. • Poor CFD approach often leads to misinterpretations and poor engineering. • Cavitation exhibits complex flow features even in the very simplest geometry. • A detailed example of numerical simulation of cavitation is shown. • Guidelines for non CFD experts on cavitation modelling are given., The research on the potential of cavitation exploitation is currently an extremely interesting topic. To reduce the costs and time of the cavitation reactor optimization, nowadays, experimental optimization is supplemented and even replaced using computational fluid dynamics (CFD). This is a very inviting opportunity for many developers, yet we find that all too often researchers with non-engineering background treat this “new” tool too simplistic, what leads to many misinterpretations and consequent poor engineering. The present paper serves as an example of how complex the flow features, even in the very simplest geometry, can be, and how much effort needs to be put into details of numerical simulation to set a good starting point for further optimization of cavitation reactors. Finally, it provides guidelines for the researchers, who are not experts in computational fluid dynamics, to obtain reliable and repeatable results of cavitation simulations.