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Global sustainable development has intensified the demand for switching to a renewable economy with a reduced carbon footprint. Here, we report a hybrid system, coupling a chemical process for CO2 reduction with hydrogen, and a biological process for polyhydroxybutyrate (PHB) synthesis, capable of converting CO2 into bioplastics with a theoretical carbon yield of 100%. The synthetic pathway from CO2 to PHB was modularly optimized by improving the catalytic efficiency of key enzymes, avoiding the kinetic trap of metabolic flux and optimizing the whole catalytic processes, resulting in 5.96 g/L PHB with a productivity of 1.19 g L− 1h− 1 and a molar CO2 utilization efficiency of 71.8%. These results represent a promising closed-loop production process from CO2 to biodegradable plastics.

The Al alloy and carbon fiber reinforced polymer (CFRP) hybrid structures, incorporating the performance advantages of the two materials, have been attracting more attention in high-end manufacturing fields. In the current investigation, the flat friction spot joining (FSJ) was employed in joining the AA6061-T6 alloy and CFRP sheets. The significance of temperature distribution in influencing joint quality was highlighted through analyzing interface microstructural features, weld defect formation as well as fractography. To understand the role of thermal energy generation and conduction in the process comprehensively, a 3D thermal-mechanical coupling finite element model was established. The interfacial temperature was characterized by an uneven distribution behavior due to the inhomogeneous heat distribution. The peak temperatures on the top surface and Al alloy to CFRP interface at 1500 rpm rotational speed with 0.1 mm/s plunging speed were 498 °C and 489 °C, respectively. The peak interface temperature was reduced to 286 °C at 250 rpm, which produced an extremely small melted area. Compared with the plunging speed, rotational speed was found to be the predominant parameter for determining the joint property, which could be optimized to simultaneously realize the avoidance of thermal decomposition of CFRP, the sufficient melting duration time, and the wide enough melted area. Simulated thermal histories and melted area profiles were in agreement with experimental ones. The findings could be utilized to provide some feasible guidance for process optimization of dissimilar FSJ of metals and composites.

The fabrication of a silver nanoparticles/chitosan/carbon nanotubes modified screen-printed carbon electrode (SPCE) as a highly sensitive platform for ultratrace mercury (II) detection was reported here. Silver nanoparticles (AgNPs) were synthesized by chitosan (CS) and carbon nanotube (CNT) hybrids with a green way. Chitosan trapped AgNPs anchoring on the sidewalls of the CNT arrange the nanoscale silver electrode arrays. Hg/Ag amalgam was formed on the surface of AgNPs/CS/CNT modified SPCE by depositing the mercury species to elemental mercury. Hg(II) detection is achieved by the stripping both Hg0 and Ag0 at +0.16V in the supporting electrolyte (0.1M HCl and 0.1 M KCl). This selective and sensitive detection method exhibits an excellent linear Hg(II) concentration range of 1.0 nM to 12.6 nM and a low detection limit of 0.4nM with R2 = 0.982 (n=13). The newly designed electrode has been successfully employed to measure Hg(II) in the textile samples with a good stability. The method demonstrates acceptable reproducibility and precision.

Friction self-piercing riveting (F-SPR) is an emerging technique for low ductility materials joining, which creates a mechanical and solid-state hybrid joint with a semi-hollow rivet. The severe plastic deformation of work materials and localized elevated temperatures during the F-SPR process yield complex and heterogeneous microstructures. The cut-off action of the work materials by the rivet further complicates the material flow during joint formation. This study employed the F-SPR process to join AA7075-T6 aluminum alloy sheets and systematically investigated the microstructural evolutions using electron backscatter diffraction (EBSD) techniques. The results suggested that as the base material approached the rivet, grains were deformed and recrystallized, forming two distinct fine grain zones (FGZs) surrounding the rivet and in the rivet cavity, respectively. Solid-state bonding of aluminum sheets occurred in the FGZs. The formation of FGZ outside the rivet is due to dynamic recrystallization (DRX) triggered by the sliding-to-sticking transition at the rivet/sheet interface. The FGZ in the rivet cavity was caused by the rotation of the trapped aluminum, which created a sticking affected zone at the trapped aluminum/lower sheet interface and led to DRX. Strain rate gradient in the trapped aluminum drove the further expansion of the sticking affected zone and resulted in grain refinement in a larger span.

A novel solid-state joining method, that we called Pressure-controlled Joule-heat Forge Welding (PJFW), in which electric resistance heat is utilized as the heat source, was successfully developed. Medium carbon steel, S45C, rods were joined using this PJFW method under various conditions. The welding temperature can be determined uniquely by the applied pressure in the PJFW. The fabricated joints show homogeneous temperature distribution and hence hardness distribution along the weld interfaces. A sound S45C joint showing superior tensile properties comparable with the base material was successfully fabricated by providing an appropriate high pressure to lower the welding temperature below the A1 point in order to prevent the brittle martensitic transformation, and applying a sufficiently large faying-surface deformation, not only to introduce significant microstructural refinement and large strains to prevent the softening, but to also sufficiently fragment the oxide layers, generate fresh surfaces, promote their atomic bonding and eliminate weld interface defects.

Colloidal gold nanoparticles (AuNPs) have been used in high technology applications due to their optical and electronic properties. Unfortunately, these broader applications are severely hampered by their agglomeration tendency and instability. Therefore, in this study, highly stable and aggregation resistant AuNPs were synthesized using Kappa carrageenan (κ-car) media (as a reducing and stabilizing agent) by a green synthesis protocol. The effect of different factors of reaction such as the concentration of κ-car (Cκ-car %), reaction time (t), temperature (T), and solution pH (here after simply define to ‘reaction parameters’) was studied by one-variable-at-a-time technique to optimize the yield production of AuNPs. The characterization of AuNPs synthesized at optimum conditions revealed that the particles are spherical in shapes, smaller in size (13.5 ± 5.1 nm) with a narrow distribution, highly crystalline (d-spacing = 0.230 nm) in nature, well stabilized (zeta potential = −22.1 mV) by coating by a thin layer of κ-car carbohydrate. The synthesized AuNPs reveal excellent catalytic function in the degradation (up to 99%) of azo-dyes. The kinetics study in the degradation reaction revealed that the technique could be extended to real wastewater treatment applications.

In situ observation of solidification cracking at the weld bead during tungsten inert gas (TIG) welding for type 310S and 316L austenitic stainless steels without the application of an external force was carried out using synchrotron X-ray radiography. The temperature distribution at the weld bead was simultaneously measured using a high-speed camera to directly determine the temperature, in which the propagation of solidification cracking occurred. The solidification cracking was clearly identified and it continuously propagated in the welding direction. The interface of the solidification cracking showed an irregular and zigzag morphology. It was found that the tip velocity of the solidification cracking periodically changed by translating between the high solid fraction (~ 90%) and the relatively lower solid fraction (~ 70%) regions at the centerline of the weld bead for both the type 310S and 316L stainless steels. The solidification cracking propagated at the lower temperature than the solidus temperature due to the segregation of low melting-point components. The tensile strain and strain rate were highly localized in the propagated area every 0.1 s which was the almost same as the time period, in which the tip velocity of the solidification cracking remarkably increased. The periodicity of the solidification cracking velocity at the weld bead can be explained by the dendrite morphology at each solid fraction and strain rate.

It is of great significance to build an efficient and cooperative innovation system and support system under the background of China persisting in leading the development with innovation and speeding up the construction of an innovation-oriented country. The collaborative relationship and profit distribution of each innovation subject will be analyzed through the study of the innovation activity in the innovation chain. With consideration of the characteristics of the innovation chain such as high risk, financing difficulty, cooperative partnership and so on and using the internal financing mode of supply chain for reference, the game model of internal financing between members of the innovation chain will be established. The game equilibriums will be solved and analyzed, and the optimal equilibriums will be achieved by designing the contracts to establish the internal financing mechanisms in the innovative chain. For the risk asymmetry at each stage of the innovation chain, the contracts will be optimized to construct the risk sharing mechanism to control the risk of the internal financing in the innovation chain. In order to make innovations, this paper creates the financial support mode of the innovation chain, improves the innovation support system and increases the efficiency of the innovation chain.

A truly simple, reproducible, and environmentally friendly non-vacuum synthesis method for synthesising of carbon-free Cu2ZnSnSe4 (CZTSe) absorber layer has been presented. The stannite CZTSe nanoparticles with an average size of about 20 nm distributions were fabricated by an ambient mechanical milling procedure using Cu2Se, Zn, Sn, elemental selenium powders as raw materials and non-toxic ethanol as solvent. The compact CZTSe thin films were formed via an annealing treatment under Ar/Se atmosphere using rapid thermal processing. The optical properties of the obtained CZTSe thin films are the absorption coefficient (α) exceeding 104 cm−1 and E g of 0.91 eV. The electrical properties of the CZTSe thin films indicate p-type semiconductor behaviour. The photovoltaic properties of this solar cell are power conversion efficiency of 0.18%.

Dissimilar friction stir welding was conducted on the combination of pure Ti and carbon fibre reinforced plastic. The weld interface microstructure and mechanical properties of the obtained joints ...

Ti-6Al-4V alloy (Ti64) and SUS316L stainless steel rods were dissimilarly friction welded. Especially focusing on the detailed observation of interface microstructural evolution during the friction welding (FW), the relationship between the processing conditions, weld interface microstructure, and mechanical properties of the obtained joints were systematically investigated to elucidate the principle for obtaining a high joint quality in the FW of Ti64 and SUS316L. A higher friction pressure produced a lower welding temperature in the FW, hence suppressing the thick intermetallic compound layer formation. However, hard and brittle Ti64/SUS316L mechanically mixed layers generally formed especially at the weld interface periphery due to the high temperature increasing rate, high rotation linear velocity and high outward flow velocity of the Ti64. These harmful layers tended to induce the cracks/voids formation at the weld interfaces hence deteriorating the joints’ mechanical properties. The rotation speed reduction and liquid CO2 cooling during the entire processing decreased the temperature increasing rate, rotation linear velocity and outward flow velocity of the Ti64 at the weld interface periphery. Therefore, they suppressed the formation of the harmful mechanically mixed layers, facilitated the homogeneous and sound interface microstructure generation, and finally produced a high-quality dissimilar joint in the FW of Ti64 and SUS316L.

Palladium nanoparticles (PdNPs) were synthesized in a green way using sodium alginate functioning as both reductant and stabilizer. The formation of as-synthesized PdNPs was supervised by Ultraviolet–visible (UV–Vis) spectroscopy and confirmed by the surface plasmon resonance (SPR) band. The effect of several synthesis factors such as precursor ratio, solution pH, reaction time, and temperature were investigated by the factorial design of experiments in order to optimize the experimental conditions. The optimal synthesis parameters were achieved by heating 1.0 ml of 1.0% sodium alginate (SA), 3.0 ml of 10−2 mol·L−1 H2PdCl4 at 80 °C for a period of 30 min in a neutral reaction medium (pH = 6). High-resolution transmission electron microscope (HRTEM), energy dispersive X-ray (EDX) spectroscopy, selected area electron diffraction (SAED) pattern, X-ray powder diffraction (XRD), and dynamic light scattering (DLS) were used to confirm the uniform spherical shapes and high crystallinity of PdNPs with average particle size of (2.12 ± 1.42) nm. The SEM images show the distribution of PdNPs presented among the SA. FTIR spectra indicate that SA is a good capping agent to stabilize PdNPs for a long time. The catalytic degradation of model azo-dyes such as mono-azo (Cibacron Yellow FN–2R) and di-azo (Cibacron Deep Red S–B) were confirmed the catalytic activity of PdNPs. The PdNPs can accelerate the degradation rate by more than 80 and 10 times respectively as confirmed by kinetics constant (k) values.

At present, the evaluation results of capacity credit of photovoltaic (PV) power generation are mainly static fixed values that are independent of time. Considering the degradation of the performance of the PV module, the capacity credit should be a time-varying value rather than a static value during the life cycle of the PV power plant. In this paper, the annual performance degradation model of a PV power station is established, and the time-varying capacity credit in the life cycle of the PV plant is simulated by calculating the year-by-year capacity credit. By adding a 100MW PV system to the IEEE-RTS 79 system for a case study, the results are as follows: the PV capacity credit is 46.04% without considering module performance decay, 45.36% in the first year when degradation is considered, and only 31.96% at the end of the life cycle. The average capacity credit over the life cycle is about 38.38%. It shows that the capacity credit varies greatly during the life cycle of PV modules, and cannot be ignored in the evaluation of capacity credit.

Silver nanoparticles (AgNPs) were synthesised utilising a one-pot green synthesis process using phytonutrients obtained from Houttugniae herba (HH) as a reductant and stabiliser. The proposed technique was fast, simple, eco-friendly, and cost-effective, and it does not require any additional processing or toxic ingredients to reduce and stabilise the AgNPs. All parameters (concentration of HH, reaction duration, temperature, and pH) involved in the reduction/stabilisation reaction were evaluated using a one-factor-at-a-time (OFAT) technique in a set of the experimental array to establish an optimal reaction state. Intense yellow colour and a prominent peak at 411 nm in the UV–vis absorption spectra indicated the growth of AgNPs in the reaction system. The produced AgNPs deploying optimum parameters were nearly spherical, with nanometre size (16.28 ± 4.48 nm), highly crystalline (d-spacing = 0.234 and 0.258 nm), and well stabilised (zeta potential = −26.4 mV). The measurement and analysis also yielded that the AgNPs were formed by an oxidation-reduction reaction between plant-derived phytonutrients and metal precursors and subsequently stabilised by the encapsulation of phytonutrients. The biogenic AgNPs exhibited remarkable antibacterial effectiveness against gram-positive and gram-negative bacteria. In addition, the AgNPs demonstrated significant catalytic degradation and mineralisation of industrially essential di-azo dyes with a degradation efficiency of nearly 100% within 20 min. The present investigation shows a simple and environmentally friendly way to synthesise AgNPs, which might be feasible to meet the current need for bacterial reduction and textile wastewater treatment.

Conductive polymer (CP) fabric is considered as the ideal electrode for flexible energy storage due to its light weight, good flexibility and high energy storage properties. However, the conventional polymer-coated cellulose fiber synthesized by liquid-phase oxidation polymerization always forms disordered assembly of polymer particles on fiber, which endures poor mechanical stability. Here, we report a two-dimensional (2D) CP based fabric electrode realized by a salt-template assisted vapor-phase polymerization method, which achieves robust coating of 2D CP on various cellulose fibers. Typically, the prepared 2D polypyrrole@cotton electrode displays a high specific capacitance (902.6 mF cm

In the present study, we evaluated the effects of high pressure torsion (HPT) and subsequent short time annealing processing on fatigue properties and cytocompatibility of the biomedical Co–Cr–Mo alloy (CCM). Before processing, CCM was solution treated (CCMST) to achieve a microstructure composed of coarse single γ-phase equiaxed grains with no internal strain. Through HPT processing, an inhomogeneous microstructure containing both micro- and nano-scaled grains is obtained in CCM specimens, which were named as CCMHPT, accompanied by high internal strain and extensive ε martensite. Following a subsequent short time annealing, a uniform single γ-phase ultrafine-grained microstructure with small local strain fields dispersed forms in CCM specimens, which were named as CCMHPTA. This microstructure change improves fatigue strength in CCMHPT, and further in CCMHPTA, because of the enhanced crack initiation and/or propagation resistance. For cytocompatibility evaluation, the cells cultured on CCMST show an immobilization tendency, while those cultured on CCMHPT exhibit a locomotion tendency. The cells cultured on CCMHPTA have an intermediate pattern. Compared with CCMST, much larger numbers of cells are proliferated in both CCMHPT and CCMHPTA. All these results demonstrate that the CCMHPTA offers an improved fatigue property and a good cytocompatibility. Therefore, it is promising for use in biomedical applications.

Stationary shoulder friction stir welding (SSFSW) is a new variant of the conventional FSW with rotation of only the tool probe to reduce the rate of heat generation along the tool–workpiece interface and hence, weld joint residual stresses. Studies on the evolution of residual stresses in SSFSW are rare as the process is new. A detailed investigation on the evolution of welding-induced residual stress is reported here for SSFSW and the conventional FSW of four different aluminum alloys. A finite element method–based numerical model, JWRIAN-Hybrid, is used for the three-dimensional heat transfer and thermo-mechanical stress analyses. The computed results are validated extensively with the corresponding experimentally measured results. The results show approximately 10% to 20% reduction in the peak residual stresses in SSFSW under identical welding conditions.

This study presents the functionalization of organic cotton fabric (OCF) by green synthesized silver nanoparticles (AgNPs). Nontoxic sodium alginate (SA) was utilized as a reducing and stabilizing agent. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV–vis spectroscopy, color coordinates, Ag content, and release (%) were used for characterization of the AgNPs and the functionalized OCF. The results reveal that AgNPs were successfully deposited on the surface fibrils of the OCF. Optimistic colors were observed from the treated OCF due to the localized surface plasmon resonance (SPR) of AgNPs. Moreover, studies of mechanical properties in terms of breaking strength and elongation at break (%), crease recovery angle, bending length, and hand-feel were performed, and better results were found in comparison with the control OCF. It was also observed that the presence of AgNPs significantly enhanced the UV resistance and antibacterial activity of the OCF.

Gold nanoparticles (AuNPs) are successfully synthesized via a facile and eco-friendly biosynthesis approach. Ginkgo biloba (G. biloba) leaf is an extract used as bio-aqueous solution for the preparation of the AuNPs. Photo-chemically, the G. biloba leaf plays dual roles wherein it serves as reducing and stabilizing agent. Through this approach, the use of toxin-induced chemical is completely avoided making the approach a green chemistry. Several synthetic parameters such as reactant concentration, media pH, reaction time and temperature are optimized which in turn enables the formation of AuNPs with uniform size. Various analytical techniques including scanning electron microscope (SEM), high resolution-transmission electron microscopic (HRTEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy, fringe spacing and selected area diffraction (SEAD) pattern, and dynamic light scattering (DLS) are used for AuNPs characterization. The AuNPs exhibit cubic structure and spherical shape with average size of 18.95 ± 5.95 nm. The homemade AuNPs show promises in the catalytic decolorization of azo-dyes in the presence of sodium borohydride (NaBH4). In addition, the AuNPs show appreciable sensitivity for the detection of Cr(VI) with a detection limit found to be 0.1–0.8 μM. This study is expected to spur further works on the use of metal nanoparticle for environmental pollution remediation.

Due to the biocompatibility and eco-friendly properties of silver nanoparticles (AgNPs), their aqueous synthesis is gaining great attention. Herein, we report the biosynthesis of AgNPs using Ginkgo biloba (G. biloba) leaf aqueous extract without using toxic chemicals. The synthesis conditions have been investigated by the factorial design of experiments (FDE) by exploring reaction conditions such as concentration ratio, media pH, reaction temperature as well as duration. The results demonstrate that the heating of 0.5 mL of as-prepared G. biloba leaf extract and 5.0 mL of 0.5 mM AgNO3 at 80 °C for 30 min in a mild alkaline medium (pH 9) were the optimal reaction parameters. The uniform spherical shapes AgNPs with particle size 14.14 ± 4.44 nm was confirmed by the techniques such as scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), energy dispersive X-ray (EDX) spectroscopy, selected area electron diffraction (SEAD) pattern and dynamic light scattering (DLS). It is clearly observed that the as-synthesized AgNPs are efficiently hindered the growth of both gram-positive and negative bacteria. Furthermore, they also showed ten times faster degradation of azo-dyes according to the pseudo-first-order kinetics and its constant (k). In addition, they demonstrated an efficient fluorescent probe for hexavalent chromium detection. The green synthesis of such environment-friendly AgNPs in bulk shows that this method has potential industrial application prospects.

The rolled Ti–15V–3Cr–3Sn–3Al (Ti-15-3) alloy (metastable β titanium alloy) sheet with an average grain size of 44.0 μm was subjected to friction stir processing (FSP) at a tool rotation speed of 250 rpm and a tool traverse speed of 100 mm/min (250–100). Thereafter, a fine-grained (∼6.6 μm) and relatively equiaxed microstructure with a high angle grain boundary (HAGB) ratio of 74.5% was observed in the stir zone (SZ). Superplastic tensile tests were then conducted on this microstructure at the temperatures ranging from 600 °C to 800 °C and strain rates range of 1 × 10 −4 -1 × 10 −2 s −1 , and an excellent low-temperature superplasticity (LTSP) with the elongation of 463% was obtained at 650 °C and 1 × 10 −4 s −1 . In addition, the microstructure in the gauge section of the tensile specimens interrupted at different engineering strains of 20%, 50%, 200%, and 463% (tensile fractured) at the optimal superplastic tensile condition of 650 °C and 1 × 10 −4 s −1 was studied. It was found that the precipitated α phase increased with the increasing strain, which contributed to the achievement of an enhanced LTSP by inhibiting the grain growth. Moreover, the α grains with a finer grain size of 4.4 μm was observed in the gauge section of the tensile fractured specimen and this was attributed to the occurrence of continuous dynamic recrystallization (CDRX). Therefore, the superplastic deformation mechanism of the Ti-15-3 alloy is recognized as grain boundaries sliding (GBS) accompanied with dislocation movement and CDRX at 650 °C and 1 × 10 −4 s −1 .

Medium carbon steel sheets of 2.6 mm thick were successfully welded by linear friction welding at various frequencies and applied pressures. The welding temperature decreased with the decreasing fr...