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One-step selectively photocatalytic phenol hydroxylation to produce Dihydroxybenzenes (DHB) is an attractive and challenging strategy. However, the rapid recombination of photogenerated carriers existed in single component photocatalyst seriously hinders the photocatalytic efficiency. The heterojunction strategy can optimize the band structure of the photocatalyst, and effectively improve the carriers' separation and transfer during the photocatalytic process. Herein, we successfully designed and prepared a 3D TiO 2 @Ni 3 Fe 1 -LDH core-shell heterostructure photocatalyst by coupling TiO 2 nanorods with Ni 3 Fe 1 -LDH nanosheets for the photocatalytic phenol hydroxylation to produce DHB. The results showed that the 3D TiO 2 @Ni 3 Fe 1 -LDH core-shell heterostructure had a suitable energy band structure for the photocatalytic phenol hydroxylation and the heterostructure accelerated the carriers' separation and transfer. Meanwhile, the high porosity and abundant active sites were conducive to the adsorption of H 2 O 2 and the photogenerated carriers transfer efficiency from the photocatalyst to H 2 O 2. The 3D TiO 2 @Ni 3 Fe 1 -LDH core-shell heterostructure showed excellent photocatalytic performance of phenol hydroxylation, where the phenol conversion was 48.6%, and the selectivity of DHB was 81.1% at 25 °C and 4 h of light illumination. Furthermore, the as-prepared photocatalysts exhibited good stability after four cycles of experiment. This work provided a convenient and efficient method for the green synthesis of DHB. 3D TiO 2 @NiFe-LDH core-shell heterostructures photocatalysts were fabricated by coupling anatase TiO 2 nanorods with NiFe-LDH nanosheets. The 3D TiO 2 @NiFe-LDH core-shell heterostructures with a suitable energy band structure for the photocatalytic phenol hydroxylation and the heterostructure accelerates the carrier separation rate showed excellent photocatalytic performance of phenol hydroxylation. [Display omitted] • 3D TiO 2 @NiFe-LDH core-shell heterostructures were fabricated. • Core-shell heterostructures accelerated photogenerated carriers' separation and transfer. • Uniformly growth of LDHs improved conductivity and light absorption of the photocatalyst. • TiO 2 @Ni 3 Fe 1 -LDH performed well in selectively photocatalytic phenol hydroxylation. • The photocatalytic phenol hydroxylation followed the mechanism dominated by.•OH species. [ABSTRACT FROM AUTHOR]

Abstract: A microwave-assisted hydrothermal approach combined with carbothermal reduction has been developed to synthesize monodisperse porous LiFePO4/C microspheres, which possess the diameter range of 1.0–1.5 μm, high tap density of ∼1.3 g cm−3, and mesoporous characteristic with Brunauer–Emmett–Teller (BET) surface area of 30.6 m2 g−1. The obtained microspheres show meatball-like morphology aggregated by the carbon-coated LiFePO4 nanoparticles. The electrochemical impedance spectra (EIS) results indicate that carbon coating can effectively enhance both of the electronic and ionic conductivities for LiFePO4/C microspheres. The Li-ion diffusion coefficient of the LiFePO4/C microspheres calculated from the cyclic voltammetry (CV) curves is ∼6.25 × 10−9 cm2 s−1. The electrochemical performance can achieve about 100 and 90 mAh g−1 at 5C and 10C charge/discharge rates, respectively. As cathode material, the as-prepared LiFePO4/C microspheres show excellent rate capability and cycle stability, promising for high power lithium-ion batteries. [Copyright &y& Elsevier]

Studies have confirmed the regulatory effects of microRNAs (miRNAs) in osteoarthritis (OA) progression. MiR-4287 has been identified by a previous study as a downregulated miRNA in chondrocytes treated with IL-1β and TNF-α. However, the function of the underlying mechanism of miR-4287 in OA is elusive. IL-1β-treated chondrocytes were used as OA cell models. RNA expression was accessed using RT-qPCR. Cell Counting Kit-8 (CCK-8) assay was used to determine the chondrocytes' viability and proliferation. The protein levels of inflammation factors (IL-8, IL-6, and TNF-α), matrix metalloproteinases (MMP 1, MMP3, MMP13), and chondrogenic genes (COL2A1, SOX9, and Aggrecan) were detected using western blot analysis. Luciferase reporter assays were performed for interaction exploration. HE staining and Safranin O/Fast Green staining was used to access the pathological changes in OA mouse tissues and cartilage degeneration in OA mouse. MiR-4287 was downregulated in chondrocytes treated with IL-1β and OA mouse models. MiR-4287 overexpression promoted the viability, and proliferation and attenuated the inflammation response and destruction of cartilage in IL-1β-stimulated chondrocytes. Receptor-interacting protein kinase 1 (RIPK1) was a target gene of miR-4287 in chondrocytes. MiR-4287 negatively regulated RIPK1 expression. RIPK1 overexpression was revealed to reverse the miR-4287-mediated effects on proliferation and inflammatory response in IL-1β-stimulated chondrocytes. Moreover, miR-4287 was demonstrated to inhibit the pathological changes, cartilage degeneration and inflammation response in OA mice models. In conclusion, miR-4287 is a critical molecule in OA development, which attenuates inflammatory response in vivo and in vitro by targeting RIPK1. [ABSTRACT FROM AUTHOR]

To solve the problems that the current seam tracking process cannot find the weld line and the control method based on the kinematic model of welding mobile robot leads to low accuracy, a method for searching the welding seam is designed firstly. By this method, the initiation point of the weld line can be found and the attitude of the robot parallel to the weld line can be adjusted automatically. Secondly, for improving the tracking precision and anti-interference performance, a new controller based on the kinematic and dynamic model of the mobile welding robot is designed. To deal with the partial uncertainty and the disturbances of welding process, this controller combines the sliding mode variable structure control and low-pass filter, so that it is able to complete the controlling of cross-slider and wheels coordinately. The stability and convergence of the designed controller are proved through the use of Lyapunov theory. The effectiveness of the proposed method is verified by simulation and experiments. In the seam tracking process, the welding torch is able to track the welding seam well and the robot moves steadily without any obvious chattering. [ABSTRACT FROM AUTHOR]

Objective. The aim of the present research is to analyze the impact of the bridge combined internal fixation system (BCFS) on efficacy, complications, and inflammatory reactions of periarticular fractures of the shoulder. Methods. A retrospective analysis was performed on 100 patients with periarticular fractures of the shoulder admitted between January 2016 and January 2020. Patients were assigned to the observation group (OG) and control group (CG) according to different treatment schemes, with 50 cases in each group. Patients in OG were intervened by BCFS, while those in CG were routinely given plate fixation. The treatment outcome, complications, and inflammatory reaction of the two groups were compared. Results. The results showed better treatment outcome, shoulder joint function recovery, and inflammatory reaction alleviation of OG compared with CG. Besides, statistically shorter fracture healing and hospitalization time as well as fewer complications were determined in OG. Conclusion. These results demonstrate that compared with the plate fixation system, BCFS can significantly improve the surgical efficacy and healing efficiency and alleviate the inflammatory response of patients, with a low complication rate, all of which contribute to faster recovery of periarticular fractures of the shoulder. Hence, BCFS is an ideal choice for periarticular fractures of the shoulder that deserves clinical promotion. [ABSTRACT FROM AUTHOR]

In this research, the thicknesses of Fe 2 Al 5 sub-layer ( l Fe2Al5 ) in bead welds were roughly calculated according to the formula l = Kt 1/2 . The values of constant K and residence time t were obtained through recording welding pools temperature. Fe 2 Al 5 sub-layers were also observed and their thicknesses were measured by SEM and EDS analysis. The calculated results were in close agreement with measured results, demonstrating the accuracy of these calculated Fe 2 Al 5 sub-layer thicknesses. [ABSTRACT FROM AUTHOR]

Three different spectroscopic methods were used to calculate the temperature and composition distribution of argon–helium arc plasma—the Fowler–Milne method, the two-line intensity correlation method and the Boltzmann plot method. Experimental errors, including random errors and systematic errors, were analyzed in detail to comparing the accuracy of different methods. Due to the large differences of physical characteristics between argon and helium, there were limited reports on the measurement of temperature and composition distribution in argon–helium arc plasma. To this end, The Fowler–Milne method and the Boltzmann plot method were modified in this paper. Three spectroscopic methods were compared with other׳s simulation result and showed good agreement with each other, except the Boltzmann plot method which had partly distinction. Through comparison and analysis of error bar in those methods, it was found that both the Fowler–Milne method and the two-line intensity correlation method had less error than the Boltzmann plot method, while the Fowler–Milne method, which is irrelevant to atomic transition probabilities and experimental apparatus calibration, had the minimum error. [ABSTRACT FROM AUTHOR]

Wrought, as-cast, and homogenized sheets were welded using the tungsten inert gas (TIG) process. The precipitates in both the base metal and the coarse-grained heat-affected zone (CGHAZ) for each joint were analyzed by optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Statistical data regarding the precipitates were also obtained from metallographs. With the alloy element contents determined by EDS and the phase diagram obtained using ThermoCalc, the diffusion of Nb and the dissolution of carbides and the Laves phase were analyzed. The wrought base metal contained massive M 23 C 6 particles and MC blocks. As the heat input increased, the amount of carbides in the CGHAZ decreased. No Laves phase was discovered in the base metal or CGHAZ. In the as-cast or homogenized base metal, MC blocks and the Laves phase were distributed in the interdendritic segregated region. As the heat input increased, the MC and Laves content did not change significantly. The prewelding heat treatment in the homogenization process reduced the amount of precipitates in the base metal. The CGHAZ of the joint of the homogenized metal lost more dendritic structure than did the CGHAZ of the joint of the as-cast metal. [ABSTRACT FROM AUTHOR]

Microstructure and properties of laser deep penetration welded Inconel 625 nickel-based alloys and SUS304 stainless steel were investigated. Weld microstructures, room temperature tensile properties and stress rupture properties, impact toughness, and hardness of dissimilar welded joints were evaluated. The experimental results showed that the microstructure of fusion zone near the fusion line in the SUS304 side was mainly cellular, whereas that near the fusion line in the Inconel 625 was predominantly columnar dendrites. Laves phases were precipitated at the grain boundary of cellular and in the interdendritic regions of fusion zone in the different form. The white transition layer was generated, and the signification change of concentrations was occurred at the fusion boundary between weld metal and SUS304. The microstructure at the fusion boundary between weld metal and Inconel 625 was characterized by dendritic boundary melting and thickening and accompanied with a lot of Laves phases precipitated in the interdendritic regions. The tensile strength tests indicated that the dissimilar butt joints ruptured in the fusion zone. The toughness of dissimilar weld metal was declined sharply compared to the two base metals. Fractographic analysis revealed that segregation of Nb and Mo in the interdendritic regions deteriorated the tensile strength and toughness of laser dissimilar weld metal. The corrosion resistance of weld metal was higher than that of SUS304 as a considerable amount of Mo elements in the weld metal inhibiting the generation and development of pitting corrosion. [ABSTRACT FROM AUTHOR]

Abstract: 5052 aluminum alloy sheets and galvanized mild steel sheets were joined in lap configuration by alternate-current double pulse gas metal arc welding with pure Al, Al–5Si, Al–12Si and Al–4.5Mg (wt%) filler wires. The effect of alloying elements on the microstructure of intermetallic compounds (IMC) layers formed between weld seam and steel, and tensile strength of the resultant joints were investigated. The thickness of IMC layer in all samples varied along the cross-section of the joint, the intermediate part of the IMC layer was thicker than the head and root parts. The diffusion of Si into Fe2Al5 sub-layer could restrain the growth of Fe2Al5 sub-layer and IMC layer, and joint's mechanical property improved with the increasing Si content in Fe2Al5 phase. Due to the high hot crack sensitivity of Al–4.5Mg alloy, cracks generated at the root of joint made with Al–4.5Mg filler, resulting in poor mechanical property. [Copyright &y& Elsevier]

Abstract: 5052 Al alloy sheets and galvanized mild steel sheets were joined by gas metal arc welding with three different current modes, including direct-current pulse gas metal arc welding (DPG), alternate-current pulse gas metal arc welding (APG) and alternate-current double pulse gas metal arc welding (ADG). The effect of current mode on size, distribution and volume fraction of pores generated in Fe–Al dissimilar materials lap joint was quantitatively studied. EDS result showed that pores in Fe–Al joint were mainly caused by trapped zinc metal vapor from galvanized steel. Volume fraction of pores in joints made by APG and ADG processes was larger than that in joint resulted from DPG process. Moreover, pores in joints made by APG and ADG processes had smaller diameter, and tended to distribute in the middle of the weld seam. On the contrary, pores with large diameter were inclined to distribute close to upper weld surface of the joint resulted from DPG process. These results are attributed to the difference of arc stirring force and linear heat input in these three processes caused by different current modes. [Copyright &y& Elsevier]

Abstract: This paper studies Al–steel lap joints resulted from direct-current pulsed gas metal arc welding (DPG) and alternate-current double-pulse gas metal arc welding (ADG). Base metals being welded are 1mm thick 5052 Al alloy sheet and 1mm thick galvanized mild steel sheet with filler metal being 1.2mm 4047. Effect of the different welding processes on joint properties is studied through characterization of the steel/Al interphases and mechanical strength. It is found that the thickness of intermetallic compound layer composed of Fe2Al5, FeAl3and Fe3Al, and the diffusion of Fe element from steel to weld seam are dependent on the amount of welding heat input. Lap shear samples of Al–Fe joints resulted from the ADG process fractured at Al base metal or weld seam with average ultimate tensile strength (UTS) of 201MPa. On the other hand, all lap shear samples of the joints resulted from DPG process fractured along the interphase between the Fe2Al5 sub-layer and the steel sheet with average UTS of 115MPa. ADG process offers higher joint strength than that offered by DPG process due to thinner intermetallic compounds layer caused by the reduced heat input, illustrating that cyclic polarity switching and a secondary low frequency current pulse can effectively reduce the heat input in joining Fe–Al dissimilar materials, which means the ADG process is much more feasible for making robust Fe–Al lap joints. [Copyright &y& Elsevier]

The turbulent flow characteristics, such as its multiscale and nonlinear nature, make the solution to turbulent flow problems complex. To simplify these problems, traditional methods have employed simplifications, such as RANS and LES models for dealing with the multiscale aspect and linear approximation theories for dealing with the nonlinear aspect. We designed a multiscale and nonlinear turbulence characteristic extraction model using a graph neural network with spatial convolutions and nonlinear fitting capabilities. Unlike traditional methods, this model computes turbulence data directly without resorting to simplified formulas. The multiscale problem is addressed by an anisotropic filter operator, and the nonlinear problem is dealt with through nonlinear correlation and nonlinear activation functions. To enhance the training efficiency of the model, a single training framework was implemented. This framework allows models trained on turbulent data with different Reynolds numbers to be applied. The relative errors for the X-axis velocity (U), Y-axis velocity (V) and pressure (P) are 0.932 %, 1.020 % and 0.594 %, respectively, when using turbulence data with the Reynolds number (Re) of 5×105 as the training set. Using Re = 1 × 103 and Re = 5 × 105 as training data and Re = 1× 105 as test data, the relative errors for U, V and P were found to be 2.527 %, 6.284 % and 0.799 % (Re = 1× 105). The study also analysed the impact of the anisotropic filter operator and nonlinearity on turbulence simulation and found that both play a critical role in turbulence calculation. These experiments demonstrate that the multiscale nonlinear turbulence simulator has a high computational performance in turbulence calculation. [ABSTRACT FROM AUTHOR]

Abstract: In deep penetration laser welding, a capillary called keyhole is formed when the energy intensity reaches 106 W/cm2. During this process, the vaporized metal and the surrounding atmosphere can be ionized to form plasma both in and above the keyhole. The stability of the keyhole has an important influence on the properties of welded components and the fluctuations of plasma. In this paper, a method was developed to acquire the stability information from plasma images taken by high-speed photography. The influences of surface impurity and the flowrate of side-assist gas on the stability were investigated. Bead-on-plate welding was performed on 12mm E-grade shipbuilding steel plates using a 15kW CO2 laser, with helium as the blowing gas. Three characteristic parameters were used to evaluate the stability. It was found that these three characteristic parameters can effectively indicate the stability variation caused by the surface impurity and gas flowrate. The present research provides important insights into developing image-based sensors to monitor the welding process. [Copyright &y& Elsevier]

BACKGROUND: Hallux valgus is a complex deformity. There is no gold standard for the treatment of hallux valgus. Osteotomy is highly recommended at present, but there are many complications. Whether we can correct hallux valgus without osteotomy is a new attempt in our group. OBJECTIVE: To explore the efficacy of an Endobutton suspension plate treatment for hallux valgus deformity. METHODS: From April 2013 to August 2018 at Department of Orthopedics, Changzhou Tumor Hospital Affiliated to Soochow University, 26 cases of hallux valgus were treated with Endobutton suspension plate, without osteotomy. All patients signed the informed consents and the study was approved by the hospital ethics committee. The hallux valgus angle and angle between metatarsal 1 and 2 were detected preoperatively and postoperatively. The American Orthopaedic Foot & Ankle Society score was detected at 12 months postoperatively. RESULTS AND CONCLUSION: (1) All patients were followed up from 8 to 38 months. (2) The hallux valgus angle (28.95±4.12)° and angle between metatarsal 1 and 2 (15.82±1.81 )° preoperatively were significantly decreased to (14.15±3.60)° and (7 .88±0.90)° postoperatively (both P < 0.01 ). (3) The American Orthopaedic Foot & Ankle Society score at 12 months after surgery (89.15±7.81) was significantly higher than that at baseline {62.08± 7.1 0) (P < 0.01 ). (4) In summary, Endobutton suspension fiXation between metatarsal 1 and 2 for treating hallux valgus is a viable treatment option. [ABSTRACT FROM AUTHOR]

The precipitates evolution in the heat affected zone of laser-welded Mg-Gd-Y-Zr alloy in T6 condition was investigated based on the TEM observation. Some oval and long-rod shape precipitates along [ 2 1 ¯ 1 ¯ 0 ] α were observed, which were not involved in precipitation sequence. Compared with isothermal aged precipitates, the overaged β′ phase presented same morphology and size, while size of needle-shape β became much smaller. The width of complete dissolution zone of the β′ is smaller than that of partial dissolution and transformation zone. • Some oval and long-rod shape precipitates along [ 2 1 ¯ 1 ¯ 0 ] α were observed in the HAZ. • Some overaged β' phase can be precipitated in the HAZ. • The size of needle-shape β in the HAZ became much smaller, compared with isothermal aged precipitates. [ABSTRACT FROM AUTHOR]

This study presents the interface microstructure, mechanical properties and corrosion resistance of dissimilar joints between Inconel 52M overlays and 316L stainless steel during multipass laser welding for nuclear power plants. The results indicate that the microstructure at the interface beside 316L stainless steel consists of cellular with the width of 30–40 μm, which also exhibits numerous Cr and Mo - rich precipitates like flocculent structure and in chains along grain boundaries as a mixed chemical solution for etching. Many dendritic structure with local melting characteristics and Nb-rich precipitates are exhibited at the interface beside Inconel 52M overlays. Such Nb-rich precipitates at the interface beside Inconel 52M overlays deteriorate the tensile strength and toughness of dissimilar joints at room temperature. The tensile strength of 316L stainless steel at 350 °C significantly decreases with the result that dissimilar joints are fractured in 316L stainless steel. The correlation between corrosion behavior and microstructure of weld metals is also discussed. The difference in high corrosion potential between Nb-rich precipitates and the matrix could result in establishing effective galvanic couples, and thus accelerating the corrosion of weld metals. [ABSTRACT FROM AUTHOR]

Thick-section steel has been widely used in many heavy industries. Traditionally, very thick steel plates could be welded by using submerged arc welding and other welding processes. However, there were more or less drawbacks in these welding methods. Laser welding, a high-energy density welding method, is being considered for such structures to improve the production efficiency and reduce the residual stresses of the joints. In this study, butt joints with narrow gap were welded using a high-power CO laser. The effect of welding parameters including the relative position between the laser beam and the filler wire, welding speed, and the distance from the intersection of the beam and wire to root of the groove on the weld bead geometry and welding defects was studied. Additionally, high-speed photography was introduced in the experiment as an efficient method to record the total process of welding, especially the transfer of molten drop. The study found that when the beam was focused on the center of the groove, the filler wire could be melted successfully even though it would tremble slightly during welding process. The optimized distance from the intersection of the beam and wire to groove root was 3 mm. Later, butt weld joints of 70-mm-thick steel plate without lack of fusion can be obtained under optimized welding parameters. [ABSTRACT FROM AUTHOR]

The defects and microstructure in the fusion zone of multipass laser welded joints with Inconel 52M filler wire are investigated for nuclear power plants. Experimental results indicate that the incomplete fusion forms as the deposited metals do not completely cover the groove during multipass laser welding. The dendritic morphologies are observed on the inner surface of the porosity in the fusion zone. Many small cellular are found in the zones near the fusion boundary. With solidification preceding, cellular gradually turn into columnar dendrites and symmetrical columnar dendrites are exhibited in the weld center of the fusion zone. The fine equiaxed grains form and columnar dendrites disappear in the remelted zone of two passes. The dendrite arm spacing in the fusion zone becomes widened with increasing welding heat input. Nb-rich carbides/carbonitrides are preferentially precipitated in the fusion zone of multipass laser welded joints. In respect to high cooling rate during multipass laser welding, element segregation could be insufficient to achieve the component of Laves phase. [ABSTRACT FROM AUTHOR]

Nanocrystalline Ni thin film exhibits poor thermo-mechanical properties due to its unstable microstructure at elevated temperature. Here, the paper endows a new approach to solve above issue via addition of nano-multilayers and incorporation of W for nanocrystalline Ni-based films, to provide novel Ni/Ni 3 Al-W nano-composite multilayered structure with high hardness and good thermal stability. The thermal evolution of microstructure and mechanical properties was investigated to reveal nanocrystalline stability and strengthening mechanisms for co-sputtered Ni/Ni 3 Al-W multilayers with varied W concentrations and annealing temperature. The lamellar structure and nonequilibrium phases are well maintained in 600 °C annealed multilayers, while nano-grains are further refined with increasing W addition. Annealing at 800 °C results in the appearance of elemental redistribution and phase separation in multilayers, leading to the layered structure dissolved and globular W-related particles precipitated. Annealing hardening is founded in most of annealed Ni/Ni 3 Al-W multilayers. Based upon microstructure observation, grain boundary relaxation and W-related phase precipitation are mainly responsible for the hardness enhancement of multilayers at 600 °C and 800 °C, respectively. Notably, the best hardness is achieved at the value of 15.6 GPa for 800 °C annealed 12.5 at% W doped Ni/Ni 3 Al-W multilayer, which shows the residual layer interfaces with larger precipitations in microstructure. This hardness increment for annealed Ni-based multilayers can be attributed that the high degree of strengthening is provided by a combination of hardening precipitation and survived lamellar structure via the Orowan mechanisms, offering a feasible insight to develop nano-metallic coatings for further increasing thermo-mechanical properties. [ABSTRACT FROM AUTHOR]

The study investigated laser welding with filler wire to determine the effects of wire feeding modes and the height of intersection of the wire and the beam ( H) on weld geometry and droplet transfer. Droplet transfer behavior was investigated using high-speed imaging. The results showed that the wire melting changed with wire feeding. The leading wire melted completely and the welding depth and width were greater due to higher levels of energy available to heat the plate in the weld pool. The transfer mode changed to liquid bridge transfer and globular transfer with increased H value. With increasing H, the frequency of droplet transfer and the droplet size varied. At 2 mm H, the droplet transfer was very stable resulting in optimum welding. [ABSTRACT FROM AUTHOR]

In order to improve the understanding on arc interference behavior and verify the welding operating point change during twin wire MIG welding, the synchronous acquisition system has been established to acquire instantaneous information of electric signals, arc profile, and droplet transfer including dynamic arc length variation. It showed that the current and voltage signals changed significantly after trailing arc (T-arc) was added to the leading arc (L-arc) in a stable welding process. Moreover, the arc agitation of L-arc increased with increasing the current of T-arc but decreased with increasing the inter-wire distance. The results also showed that the stable spray transfer of L-arc was destroyed and deflected due to the effect of T-arc. With respect to a single wire welding, the arc length of L-arc increased and the welding operating point changed during the twin wire welding. [ABSTRACT FROM AUTHOR]

Equimolar CrMnFeCoNi high entropy alloy (HEA) is one of the most notable single phase multi-component alloys up-to-date with promising mechanical properties at cryogenic temperatures. However, the study on the corrosion behavior of CrMnFeCoNi HEA coating has still been lacking. In this paper, HEA coating with a nominal composition of CrMnFeCoNi is fabricated by laser surface alloying and studied in detail. Microstructure and chemical composition are determined by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) are used to investigate the corrosion behavior. The coating forms a simple FCC phase with an identical dendritic structure composed of Fe/Co/Ni-rich dendrites and Mn/Ni-rich interdendrites. Both in 3.5 wt.% NaCl solution and 0.5 M sulfuric acid the coating exhibits nobler corrosion resistance than A36 steel substrate and even lower i corr than 304 stainless steel (304SS). EIS plots coupled with fitted parameters reveal that a spontaneous protective film is formed and developed during immersion in 0.5 M sulfuric acid. The fitted R t value reaches its maximum at 24 h during a 48 h’ immersion test, indicating the passive film starts to break down after that. EDS analysis conducted on a corroded surface immersed in 0.5 M H 2 SO 4 reveals that corrosion starts from Cr-depleted interdendrites. [ABSTRACT FROM AUTHOR]

Nanocrystalline (NC) Ni 3 Al thin films have poor mechanical properties at a high temperature and in order to improve the thermal performance, it is necessary to develop novel micro- or nanostructures that endow the coatings with both high thermal stability and hardness. In this work, Ni 3 Al thin films with different W concentrations up to 12.5 at% are deposited on Si/SiO 2 substrates by magnetron sputtering and then vacuum-annealed at 500 °C and 700 °C. Addition of W to the nanostructured Ni 3 Al thin films leads to grain refinement and high thermal stability. The hardness ( H ) of the film with 12.5 at% W annealed at 700 °C increases by 355% compared to pure Ni 3 Al. X-ray diffraction and transmission electron microscopy reveal non-equilibrium phases such as the amorphous phase and supersaturation solid solution in the films annealed at 500 °C. After annealing at 700 °C, the α-W phase precipitated in the fine nanocrystalline state plays a crucial role in the high thermal stability of the nano-grains as well as enhanced hardness. The results suggest that these durable Ni-based coatings are suitable for applications at high temperature. [ABSTRACT FROM AUTHOR]

The corrosion behavior and interfacial contact resistance (ICR) of Mg–Nd–Zn–Zr magnesium alloy in simulated PEMFC environments are investigated systematically. The corrosion rate decreases logarithmically with the immersion time due to accumulation of corrosion products. At first, Mg–Nd–Zn–Zr magnesium alloy exhibits lower corrosion rate in anodic environment because the reactions involving formation of hydrogen gas and dissolution of magnesium are inhibited. After long time immersion, it presents higher corrosion rate because of pitting corrosion and cracked corrosion products layer. In the cathodic environment, a compact corrosion products layer composed of amorphous MgCO 3 and Mg(OH) 2 is formed as a result of precipitation of carbonate-containing corrosion products. The ICR of Mg–Nd–Zn–Zr magnesium alloy immersed in cathodic environment is higher than that in anodic one due to the accumulation of amorphous Mg(OH) 2 and MgCO 3 corrosion products layer. [ABSTRACT FROM AUTHOR]

Nano-structured Ni/Ni 3 Al multilayer was prepared by magnetron sputtering, with individual layer thicknesses h varying from 10 to 160 nm. The microstructure and hardness of Ni/Ni 3 Al multilayer were investigated by X-ray diffraction, transmission electron microscopy and nanoindentation. The results show that the hardness increases with decreasing h for as-deposited and 500 °C annealed multilayers. When annealed at 700 °C, the hardness approach a peak value at h = 40 nm with followed by softening at smaller h . The influence of individual layer thickness, grain size as well as formation of ordered Ni 3 Al on strengthening mechanisms of Ni/Ni 3 Al multilayers at elevated temperature are discussed. [ABSTRACT FROM AUTHOR]

The microstructure evolution in the fusion zone of laser-welded Mg-Gd-Y-Zr alloy during solution and aging treatment is investigated. The morphology of the Mg 24 (Gd,Y) 5 in the divorced eutectic at the grain boundary transforms from a continuous network to disconnected and fragmentized islands and then to spheroidal particles before complete dissolution during the solution treatment at 430 °C. During the subsequent aging treatment at 225 °C, the precipitation sequence in the fusion zone follows the order of supersaturated solid solution (SSSS) → βʺ(D0 19 ) → βʹ(cbco) → β 1 (fcc) → β(fcc). High-density precipitates are present at the original grain boundaries of the fusion zone from the welded structure but there are less precipitates in the interior of the original grains. The grain growth during the solution treatment at 430 °C comprises the slowly increasing stage, rapidly increasing stage, and stable stage. The network-distributed Mg 24 (Gd,Y) 5 impedes migration of the grain boundaries, restricts grain growth in the first slowly increasing stage, and segregation of zirconium near the grain boundaries also affects migration of the grain boundaries. [ABSTRACT FROM AUTHOR]

Magnesium alloy bipolar plates offer great advantage in weight reduction of polymer electrolyte membrane fuel cell. An attempt to improve the corrosion resistance and surface conductivity of magnesium alloy has been made by a medium electroless plating Ni coating prior to PVD deposition of carbon film, envisaging the application of these coating/substrate systems as bipolar plate in PEMFC. The results show that Ni + C coated magnesium alloy GW83 has the best corrosion resistance of 8.65 μA cm −2 and 0.80 μA cm −2 in the simulated cathodic and anodic environments. The release of metallic ions is also greatly inhibited by Ni + C coating. The interfacial contact resistance (ICR) of the magnesium alloy GW83 is decreased from 196.5 mΩ-cm 2 to 2.97 mΩ-cm 2 by Ni + C coating at the compaction force of 150 N-cm −2 . After potentiostatic tests, Ni + C coated sample has the lowest ICR of 15.6 mΩ-cm 2 and 52.6 mΩ-cm 2 in the anode and cathode environment, respectively. [ABSTRACT FROM AUTHOR]

The effects of W doping on the microstructure, ICR, and corrosion resistance of carbon films are systematically investigated. The W-doped carbon film has a compact structure and the surface topography changes slightly with W concentration. W exists in mainly the metallic state when the concentration is small, but amorphous WC is formed in the C W2(A) and C W3(A) samples. The ICR at a typical compaction force of 150 N cm −2 increases marginally in the range of 6.25–7.21 mΩ-cm 2 as the W concentration is varied. The carbon films with smaller W concentrations have better corrosion resistance and even the self-passivating ability. During pulse polarization, the bare SS316L shows a very large current density of 150 μA cm −2 due to breakdown of the passive film, but C W1(A) shows a stable and low current density of about 0.6 μA cm −2 due to the good self-passivating ability. The self-passivating ability originates from oxidation of metallic state W in the carbon film and so a proper W concentration can yield the desirable self-passivating effect. [ABSTRACT FROM AUTHOR]

By matching with the welding speed, the distance between the laser focus and butt seam was adjusted to obtain various fusion ratios of the two base metals. The main phases in weld metal were martensite and retained austenite whose proportions and morphology were measured by XRD and EBSD, respectively. The proportion of retained austenite, both at grain boundary and among martensite laths in core region of grain, increased with the fusion ratio of SUS304. The maximum content of retained austenite at grain boundary and in core region of grain could reach about 22% and 5.8%, respectively. The low-temperature impact toughness of the joint was improved with the increment of retained austenite content. The low-temperature impact energy at −196 °C had displayed a significant raise from 15 J to 44.3 J. The corresponding impact fracture section also transformed from cleavage fracture to entirely ductile fracture. [ABSTRACT FROM AUTHOR]

The current study investigates the overlays deposited by laser beam (LB) and gas tungsten arc (GTA) cladding with Inconel 52M filler wire in nuclear power plants. The effects of the deposition methods on the cross section profile, microstructures, and mechanical properties of both overlays are studied using optical microscope, scanning electron microscope (SEM), tensile and impact test and microhardness measurements. Experimental results show that LB cladding with higher wire feed rate improves the deposition efficiency as compared with GTA cladding. The microstructure of the LB clads consists of cellular and columnar dendrites, and Nb-rich spherical particles are precipitated in the interdendritic regions, while the equiaxed dendrites are dominant in the GTA clads. The microhardness of the GTA clads is 20-30 HV higher than that of the LB clads. Furthermore, the tensile strength, toughness, and elongation of the LB clads decrease in comparison to the GTA clads. The deep penetration of the LB clads resulting in a wave shape of each pass and high dilution does not benefit the mechanical properties as compared with the GTA clads. [ABSTRACT FROM AUTHOR]

In order to better understand the arc interference behavior and welding stability in twin wire GMA welding, the synchronous acquisition system has been established to acquire instantaneous information of electric signals, arc profile, and droplet transfer including dynamic arc length variation. The results showed that after Trailing arc (T-arc) was added to the Leading arc (L-arc) in a stable welding process, the current of L-arc decreased and the voltage kept constant. The stable globular transfer of L-arc was destroyed and deflected, turned into spray transfer due to the effect of T-arc. Compared to the single wire welding, the arc length of L-arc increased and the welding operating point changed in twin wire welding. [ABSTRACT FROM AUTHOR]

The carbon film with electroless nickel interlayer (Ni + C) was fabricated to improve the corrosion resistance of the magnesium alloy GW83. Compared to other coatings used in this study, the dense Ni + C coating improved adhesion with the substrate. The corrosion potential ( E corr ) of the Ni + C coated magnesium alloy was about −1.37 V vs saturated calomel electrode (SCE) in contrast to about −1.67 V vs SCE of the bare one in 3.5 wt% NaCl solution. The corrosion current density was reduced from 186 μA cm −2 to 11 μA cm −2 . The 5 h immersion test revealed that the Ni + C coated magnesium alloy GW83 showed much less corrosion compared to the bare alloy. These evidences indicated that applying Ni + C coating could effectively improve the corrosion resistance of the magnesium alloy GW83. [ABSTRACT FROM AUTHOR]

Effects of mechanical constraint intensity on solidification cracking behavior were investigated in single-side and double-side constraint conditions, respectively. A numerical model was developed to simulate the solidification cracking behavior during the laser welding process. The mechanical strain and accumulated crack-tip displacement were adopted to analyze the susceptibility of crack initiation and propagation, respectively. Results show that crack behavior is greatly influenced by mechanical constraint intensity. Stronger constraint intensity promotes the initiation of crack for both single-side and double-side constraint conditions. Higher constraint intensity tends to promote crack propagation in single-side constraint condition, and helps to suppress crack propagation in double-side constraint condition. [ABSTRACT FROM AUTHOR]

Laser-welded steel sandwich constructions have gained their popularity as typical lightweight structures, and the welding quality is a critical point for their comprehensive performance. The special welding mode for the T-joint of an I-core sandwich plate proposes challenges that the incident laser should align the web plate. A novel method of deviation detection based on the metallic vapor plume for CO laser welding of I-core sandwich plates is investigated in this paper. On the basis of the plume images captured by a high-speed camera, the characteristics of instantaneous plasma plume are calculated, and their process parameters are extracted statistically in time domain and frequency field. Furthermore, principal component analysis (PCA) is employed to synthesize the information of all feature parameters, and a complex indicator was formed to evaluate the deviation status. Experimental results showed that the monitoring method based on the characteristics of vapor plume was convenient, effective and promising in production. [ABSTRACT FROM AUTHOR]

Poor wear resistance of rare earth magnesium alloys has prevented them from wider application. In this study, composite coating (PVD carbon coating deposited on electroless plating nickel interlayer) is prepared to protect GW83 magnesium alloys against wear. The Ni + C composite coating has a dense microstructure, improved adhesion strength and hardness due to the effective support of Ni interlayer. The wear test result shows that the Ni + C composite coating can greatly prolong the wear life of the magnesium alloy. The wear track of the Ni + C coated magnesium alloy is obviously narrower and shows less abrasive particles as compared with the bare one. Abrasive wear is the wear mechanism of the coatings at the room temperature. In conclusion, the wear resistance of the GW83 magnesium alloy can be greatly improved by the Ni + C composite coating. [ABSTRACT FROM AUTHOR]

The ultrafine attapulgite powders (UAP) were prepared using natural attapulgite powders (NAP) by the ball-milling dispersion method. The tribological behaviors of surface-modified NAP and UAP dispersed into mineral base oil were investigated. SEM, EDS, XPS and a microhardness tester were utilized to analyze the tribofilm formed on the worn surfaces. It is found that both the additives can improve the friction-reduction and anti-wear properties of the base oil. A tribofilm mainly composed of FeO, Fe 2 O 3 , FeOOH and SiO formed on the worn surface lubricated with oil containing NAP and UAP. And the content of iron oxides and SiO formed on the worn surface lubricated with oil containing UAP is much higher, which is responsible for the better friction-reduction and anti-wear properties of UAP. [ABSTRACT FROM AUTHOR]

Tribological properties of attapulgite, Ni and their composite nanoparticles suspended in mineral lubricating oil for a steel-steel contact were investigated with an optimal SRV-IV oscillating friction and wear tester. Results demonstrated that the composite nanoparticles exhibit better friction-reduction and anti-wear properties than the single additives. The oil containing a composite powder of 0.5 % attapulgite and 0.1 % Ni owns the best friction-reduction and anti-wear properties. Under the lubrication of oil containing composite nanoparticles, a smooth and compact tribofilm mainly composed of iron oxides, Ni, NiO and silicon oxide was formed on the rubbing surface. [ABSTRACT FROM AUTHOR]

To improve the corrosion resistance and surface conductivity of stainless steel bipolar plate, C/Al–Cr–N multilayer coatings with varying Al:Cr target current are deposited on stainless steel 316 L (SS316L) by magnetron sputtering. Scanning electron microscope (SEM) results show that the coating is about 2.3 μm in total thickness, consisting of 0.9 μm carbon layer and 1.4 μm Al–Cr–N sub-layer. The interfacial contact resistance (ICR) result indicates that the surface resistance decreases with the increasing content of chromium, and achieves the minimum value of 6.17–4.88 mΩ-cm 2 at the compaction force between 120 and 150 N cm − 2 for the Al2Cr4 sample. The electrochemical and inductively coupled plasma atomic emission spectrometry (ICP-AES) results disclose that C/Al–Cr–N multilayer coatings with Cr:N atomic ratio of 1:1 and lower aluminum content have higher chemical inertness and better corrosion resistance. Al6Cr0 and Al5Cr1 samples exhibit more negative corrosion potential and higher passive current density with galvanic corrosion on the surface due to the existence of AlN phase. Therefore, C/Al–Cr–N multilayer coatings with lower aluminum content are preferred for bipolar plate application. [ABSTRACT FROM AUTHOR]

The effect of processing parameters, assembly parameters, and plate thickness on the weld bead geometry was examined, and the microstructure and microhardness of the typical joints were investigated in this paper. There are two kinds of welds, these are the Y-type and V-type welds in different heat input. Heat input has a small effect on bead width at the interface when the thickness of face plate is more than 3 mm. The variation of bead geometry is little when gap and offset size is small, while porosity or depression forms with increasing gap and offset. Plate thickness exerts a remarkable effect on the bead width at interface, and a big bead width at interface can be achieved by adopting thin face plate. The centricity of the laser beam is a big problem in laser lap welding T-joints with thin core plate, while bead width at interface is small in laser lap welding T-joints with thick face plate. Microstructure of heat-affected zone and fusion zone is composed of lath martensite and bainitic ferrite. Microhardness of fusion zone is lowest due to the coarse lath martensite. The desired bead geometry of laser lap welded T-joints can be produced by adopting low welding speed, thin face plate, and small gap. [ABSTRACT FROM AUTHOR]

Laser-induced plasma has been one of the hotspots of high-power CO laser welding for many years. A novel method was proposed to suppress the plasma plume through external constraints, which resulted in more stable welding process and slightly increased penetration depth. Based on high-speed camera and image processing technology, it was demonstrated that the expansion of plasma plume both in height and width was suppressed by a pair of water-cooled copper blocks laid near laser incident point along the direction of seam. Besides its intensity and size, the dynamical behavior of plasma plume under spatial constraint was observed and analyzed by the characteristic parameters. The constraint mechanism and influence of the spacing between the two copper blocks was discussed. Results showed that external constraint was effective to suppress plasma plume, stabilize welding process, and to increase weld penetration for high-power CO laser welding. [ABSTRACT FROM AUTHOR]

Abstract: A high-speed camera and X-ray transmission observation system were used to observe the keyhole and molten pool dynamic behavior in laser lap welding T-joints. The oscillation frequency of the molten pool and the keyhole increases with increasing gap. The lower keyhole becomes slant with the large gap and large quantities of bubbles are formed at the bottom tip of the keyhole. The molten pool is divided into three different zones by the large gap and a small eddy is formed at the lower molten pool. The bubbles are difficult to escape from the lower molten pool and the gap when the gap is large, resulting in the formation of porosity at the gap and root of weld seam. The distribution characteristics of porosity in different gap have an excellent agreement with the keyhole and the molten pool dynamic behavior. Porosity can be suppressed by maintaining a small gap or adopting high welding speed. The paper provides fundamental insights into the mechanism of porosity formation during laser lap welding T-joints and guidance to aid in its elimination. [Copyright &y& Elsevier]

Highlights: [•] We investigate the effect of natural attapulgite powders as lubrication additive on the friction and wear performance of a steel tribo-pair. [•] Attapulgite powders can remarkably decrease the friction coefficient and wear rate of carbon steel friction couples. [•] A tribofilm composed of iron oxides and silicon oxides has formed on the worn surface under the lubrication of oil containing attapulgite powders. [•] We reveal the friction-reducing and anti-wear mechanism from the standpoint of tribochemistry, mineralogy and materials science. [ABSTRACT FROM AUTHOR]

In this paper, an experimental study combined with a numerical model consideration of both thermal conduction and fluid flow in the molten pool were carried out, aiming to analyze solidification cracking susceptibility of dual-beam laser welding on Al alloys. The maximum accumulated transverse displacement in the mushy zone was calculated based on the strip expansion technique and employed to evaluate centerline solidification cracking susceptibility. Numerical calculations showed that increasing inter-beam spacing in side-by-side dual-beam laser welding of Al alloys could lead to increased accumulated transverse displacement in the weld, resulting in higher solidification cracking susceptibility, which agreed well with experimental observations. The analysis results also showed that increasing the laser power or reducing the welding velocity increased hot cracking susceptibility. The optimum cracking-free welding condition for dual-beam laser welding of Al can be determined with the help of numerical modeling, in which the hot cracking susceptibility can be evaluated and numerically reduced by adjusting welding process variables. [ABSTRACT FROM AUTHOR]

Abstract: Aluminum bipolar plates offer good mechanical performance and availability for mass production while allow up to 65% lighter than stainless steel. To improve the corrosion resistance and surface electrical conductivity of aluminum bipolar plates, several coatings, including TiN, CrN, C, C/TiN and C/CrN, are deposited on aluminum alloy 5052 (AA-5052) by close field unbalanced magnetron sputter ion plating. Scanning electron microscope (SEM) results show that the coatings containing carbon layer are denser than TiN and CrN. Although the potentiodynamic test results show improved corrosion resistance by all the coatings, the potentiostatic test results reveal different stability of these coatings in PEMFC environments. Comparing the SEM images of these coatings after potentiostatic test, C/CrN multilayer coating exhibits the best stability. C/CrN multilayer coated AA-5052 has the lowest metal ion concentration after potentiostatic test, being 11.12 ppm and 1.29 ppm in PEMFC cathodic and anodic environments, respectively. Furthermore, the interfacial contact resistance (ICR) of the bare AA-5052 is decreased from 61.58 mΩ-cm2 to 4.08 mΩ-cm2 by C/CrN multilayer coating at the compaction force of 150 N-cm−2. Therefore, C/CrN multilayer coating is a good choice for surface modification of aluminum bipolar plate. [Copyright &y& Elsevier]

Abstract: Side assisting gas plays a very important role in the laser-induced plasma suppression and the gas mixture ratio directly influences the formation and behavior of the laser-induced plasma during the laser welding process. In this paper, a photography system was set up with three synchronous CCD cameras to record the plasma plume during CO2 laser welding under different He–Ar ratios for helium–argon mixed side assisting gas. Three-dimensional reconstruction of the laser-induced plasma based on the computed tomography (CT) technology was achieved from the images shot by the cameras. Four characteristics, including the volume, uniformity, parameter P A associated with plasma absorption and parameter P R associated with laser refraction, were extracted from the 3D plasma and analyzed to investigate the effect on the plasma plume morphology as well as the laser energy attenuation. The results indicated that the He–Ar ratio of the side assisting gas has a considerable influence on some characteristics while some other characteristics are not sensitive to the mixture ratio. In addition, the effect of He–Ar ratio on the laser-induced plasma varies a lot with the flow rate of the side assisting gas. [Copyright &y& Elsevier]

A mathematical model of laser welding steel with a T-joint was developed in this paper to investigate the formation process of keyhole-induced porosity, helping to understand the mechanism of porosity formation in laser welding steels with heavy section. Solidification model and adiabatic bubble model were coupled in this model, which could more approximately reflect the formation process of bubble and its evolution into porosity. The volume-of-fluid (VOF) method was taken to track free surfaces of keyhole and porosity. The numerical results showed that the unstable keyhole during the laser welding process induced the collapse of keyhole and then resulted in bubbles in the molten pool. These bubbles moved following with the fluid flow in the molten pool, where some bubbles could escape out of molten pool under the competition of flow and solidification speed. But some bubbles captured by a solidified wall during the migration process in the molten pool would evolve into porosities. It was also found that some bubbles formed adjacent to a fusion line were easier to be captured by a solidification surface, which could give explanation for some porosities occurring close to the fusion line. A good agreement of simulation and experimental results proved the reliability of this mathematical model, while the mechanism of porosity formation was better clarified with this model. [ABSTRACT FROM AUTHOR]

Abstract: High electrical conductivity and corrosion resistance are central to advances in wider application of metallic bipolar plates in polymer electrolyte membrane fuel cell (PEMFC). In this study, C/Cr–Ti–N multilayer coatings are deposited by physical vapor deposition and the effect of Cr:Ti ratio on the corrosion resistance and interfacial contact resistance (ICR) are systematically investigated. Scanning electron microscopy (SEM) result shows that the carbon layer is compact and uniform. Excellent corrosion resistance of 0.127 μA cm−2 current density at operating voltage in PEMFC cathode environment and low ICR of 2.03 mΩ-cm2 at compaction force of 150 N cm−2 are achieved when Cr:Ti ratio is 2:4 and 3:3, respectively. The significant enhancement in surface conductivity is probably because that the current comes from carbon paper is homogenized by two electrically conductive layers and flows to the passive film with much more contact area. After polarization, ICR increase to 3.07 mΩ-cm2 and 3.02 mΩ-cm2 in the simulated PEMFC cathode and anode environment, respectively. However, the Raman spectroscopy results disclose that the bonding type of top carbon film before and after polarization shows little difference. The results indicate that C/Cr–Ti–N multilayer coating with Cr:Ti ratio of 2:4 achieves the optimal composition. [Copyright &y& Elsevier]

Abstract: The microstructure of the laser clad Inconel 718 alloy coating was observed by scanning electron microscope (SEM). The chemical composition of precipitation phases was investigated by energy dispersive spectrometer (EDS) and solid phase microextraction (SPME). The crystal structure and lattice constants of precipitation are determined by transmission electron microscope (TEM). Vickers hardness of the coatings and the nanohardness of the interstitial phases were measured. The insular carbide (MC) and the tetragonal nitride (MN) with face-centered cubic (FCC) structure are rich in Ti and Nb but depleted in Ni, Fe and Cr due to the interdiffusion and redistribution of alloying elements between MC and MN and supersaturated matrix. MC and MN were precipitated in the forms of (Nb0.12Ti0.88)C1.5 and (Nb0.88Ti0.12)N1.5, and the Gibbs free energies of formation can be expressed as and . The nanohardness and Young's modulus of the MC and MN were much higher than the matrix, and the plastic deformation energy of interstitial phases was lower than the matrix. The precipitation of MC and MN is beneficial to the mechanical properties of coating. [Copyright &y& Elsevier]

The aim of the present research is to discuss the effect of gap on plasma plume, keyhole, and molten pool dynamics during laser lap welding for T-joints. The authors observe plasma plume, keyhole opening, and molten pool images by high-speed camera in different gaps during CO laser overlap welding of T-joints. The results show that gap causes beam energy fluctuations in the keyhole and leads to the instability of welding process. In laser spot welding, zero-gap and small gap greatly affect the stability of plasma and keyhole, which causes the formation of cavities in the weld metal, while a proper gap can help prevent porosity formation. In laser continuous welding, the disruption and closure of front keyhole wall at the gap periodically changes with the gap, which causes the formation of plenty of porosities at the gap. The instability of keyhole is closely related to dynamics of plume and molten pool, which gives an insight into the mechanism of porosity formation during laser overlap welding. [ABSTRACT FROM AUTHOR]