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The achievement of fine equiaxed β grain with conventional intragranular (α-Ti+β-Ti) microstructure in additive manufacturing titanium alloy remains a big challenge. We conquer this challenge by synergistically controlling β-grains during both solidification and subsequent thermal-cycles of laser directed energy deposition (DED), and a solution + quenching heat-treatment. Both the strength and plasticity of heat-treated Ti6Al4V3Ni0.05B are superior to those reported new DED titanium alloy and comparable to that of DED Ti6Al4V, because of the fine-equiaxed β-grains with intragranular (α-Ti+β-Ti) microstructure. These findings provide new insight into the grain structure control and the composition design of AM titanium alloy. The synergetic control of β-grain during both solidification and subsequent thermal-cycling is essential for achieving fully-equiaxed fine β-grains in additively manufactured titanium alloys.

In the field of flexible electronics manufacturing, inkjet printing technology is a research hotspot, and it is key to developing low-temperature curing conductive inks that meet printing requirements and have suitable functions. Herein, methylphenylamino silicon oil (N75) and epoxy-modified silicon oil (SE35) were successfully synthesized through functional silicon monomers, and they were used to prepare silicone resin 1030H with nano SiO2. 1030H silicone resin was used as the resin binder for silver conductive ink. The silver conductive ink we prepared with 1030H has good dispersion performance with a particle size of 50–100 nm, as well as good storage stability and excellent adhesion. Additionally, the printing performance and conductivity of the silver conductive ink prepared with n,n-dimethylformamide (DMF): proprylene glycol monomethyl ether (PM) (1:1) as solvent are better than those of the silver conductive ink prepared by DMF and PM solvent. Cured at a low temperature of 160 °C, the resistivity of 1030H-Ag-82%-3 conductive ink is 6.87 × 10−6 Ω·m, and that of 1030H-Ag-92%-3 conductive ink is 0.564 × 10−6 Ω·m, so the low-temperature curing silver conductive ink has high conductivity. The low-temperature curing silver conductive ink we prepared meets the printing requirements and has potential for practical applications.

The holograms in Star Wars have inspired many researchers to capture the whole human body in real-time and present it as an avatar into Virtual Reality (VR). Facial capture is important to achieve this because facial expressions are essential for social interaction. However, facial capture works well only when the face is not occluded. While a VR headset has been widely used as a display device for VR, it occludes half of the face and becomes an obstacle. This paper presents a systematic literature review on facial capture for VR. The survey aims to: review the current state-of-the-art facial capture technologies for VR; identify the types of technologies and context of the use, the methodologies, and theoretical groundings; identify research gaps in facial capture for VR; and identify solutions of facial capture for VR headsets. A realism index is defined to evaluate and compare the collected papers. The results show several technology trends in the facial capture for VR: tracking facial motion with markers, facial capture in headsets using cameras or sensors, facial performance capture, and hologram/volumetric capture. It is shown that the Modular Codec Avatar is the best facial capture method in a VR headset, whereas Metahuman has the best output effects. This paper also proposes that an open-design VR headset is an effective approach to lower the Total Cost of Ownership (TCO).

For the open loop control system based on the solar position algorithm (SPA), without sensor correction, the error of SPA will bring the tracking error directly to decrease the efficiency of the solar system. By comparing with SPA proposed by NREL, this paper first evaluates main SPAs with different accuracy and presents the error of SPA on tracking error. Based on the annual average efficiency of the solar trough system, this paper evaluates the impact of the tracking error caused by SPA on the solar trough system, and proposes that the average SPA calculation error can be applied to characterize the impact of SPA on the trough solar system. By making a comparison of solar trough system efficiency calculated with fixed annual average tracking error and normal constantly changing tracking error within a year, respectively, the evaluation results show that for most SPAs, the introduced error is less than 0.05%, and only a few empirical algorithms with large tracking errors introduce larger errors, but they are not suitable for the trough solar system. Therefore, the SPA evaluation method proposed in this paper is applicable to the solar trough system.

Selective laser melting (SLM) is a manufacturing technology that involves melting metal powder beds. Due to the temperature gradient during the course of forming, anisotropy is further caused by oriented grain growth. However, the influence of process parameters on anisotropy has not been studied. Two types of parameter scanning strategies and rotation angle increments were selected to alter the growth tendency of grains, thus affecting anisotropy. Comparing the STRIPES scanning strategy and the CHESS strategy, the latter can restrain anisotropy, while in the former, the anisotropy of tensile stress is influenced by the layer angle increment. The maximum tensile strength of SLM-formed parts in the formed direction deviates from an angle of 60° (1235 MPa and elongation of 5.3%), and the maximum microhardness property appears at the formed direction surface, namely, the top side surface (487 HV).

The failure of transpassive films on transition metal alloys was investigated. The results show that the failure of the transpassive film on 3D printing nickel-based superalloy in flowing NaNO3 solution is dominated by self-induced cracking of the film on niobium-segregated phases and the erosion-induced degradation on the film assisted by cation vacancy condensation at the metal/barrier layer interface. Secondary passivation induces the formation of a transpassive film, the nature of which has been debated for decades. The findings are consistent with a bi-layer structure comprising a point-defective barrier layer that grows into the substrate alloy and a precipitated outer layer.

Apple tree canker induced by Valsa mali is a vital disease in apple production around the world, and it highlyimpacts the development of apple industry. It is of great significance to study the inhibition effect of common fungicides and develop new fungistats for comprehensive control of apple tree canker. In this experiment, the inhibition activity of five fungicides, including mancozeb, metalaxyl, iprodione, prochloraz, and difenoconazole along with biosynthesized nanosilver against V. mali, were measured with the mycelium growth rate and agar well diffusion methods. The results showed that iprodione exhibited the best inhibitory effect, the median inhibition concentration (IC50) of iprodione and nanosilver was 0.62 μg.mL−1 and 45.50 μg.mL−1, the suppression rate achieved 67.93% at 200 μg.mL−1 of nanosilver. Moreover, a remarkable additive and synergistic antimicrobial effect was verified when silver nanoparticles were conjugated with iprodione at 9:1, 8:2, 7:3, and 6:4 (v/v), and the toxicity ratio was 1.04, 1.13, 1.01, and 0.98, respectively. It is proven that biosynthesized silver nanoparticles could effectively inhibit Valsa mali, and it is possible to develop and screen silver nanoparticle-based nano pesticides to manage plant diseases synthetically.

Peritectic solidification has attracted increasing attention as a lot of important binary alloys, such as Fe–Ni, Zn–Cu, Fe–C and Ti–Al, exhibit peritectic reaction during solidification. In order to investigate the solidification behavior of Zn-rich Zn–Cu peritectic alloy containing nominally up to 7.8 wt.% Cu, a series of laser surface remelting experiments were performed. With the increase in growth velocity, Zn–Cu alloys with Cu content below 3.0wt.% showed an evolutional sequence from low-velocity η planar interface → lamellar structures → η shallow cells and finally to high-velocity η planar interface. The Zn-4.0 wt.%Cu alloy showed a similar transitional sequence except that irregular η cells appeared when low-velocity planar interface became unstable. In contrast, e cell/dendrite was the typical microstructure of the Zn-7.8 wt.% Cu alloy within the whole scanning velocity range. Based on the maximum interface temperature criterion, a eutectic growth model under rapid solidification conditions (TMK model) and a self-consistent numerical model for the cellular and dendrite growth were applied to establish a phase and microstructure pattern selection map, which drew a clear whole picture of the relationship between phase/microstructure and solidification conditions of this series of alloys. Regarding the microstructure feature, our investigation revealed the range of the solidification velocity and chemical composition of lamellar structures as dominant microstructure and their lamellar spacing displayed a considerable range of the average value as a function of growth velocity. The relationship between the lamellar spacing and the growth velocity was further analyzed by using the TMK eutectic model, and the results showed the same overall trend as the experimental results. A phase and microstructure pattern selection map of Zn-rich Zn–Cu peritectic alloys. Regression analysis of the average spacing of lamellar structures.

Copper oxide (CuO) nanoparticles were synthesised from Ginkgo biloba L. leaf extract and several parameters that affected their formation were adjusted. The optimal synthesis system was ascertained as 10 ml leaf filtrate, 1 mM copper sulfate, and 80°C. The scanning electron microscope image showed that the synthesised CuO nanoparticles were shaped like a short rod. The antifungal effect of CuO nanoparticles against Bipolaris maydis was operated through agar well diffusion, mycelial growth, spore germination, and detached inoculation. At the concentration of 200 µg/ml, the suppression rate was up to 62.78%, and the spore germination was totally inhibited irrespective of suspension in a liquid or on detached maize leaf. The results are of great significance for comprehensive control of plant diseases, and it also provides a novel antimicrobial to assist or substitute chemical pesticides.

Linear segregation of high strength aluminum alloy ZL205A castings were studied by X-ray Nondestructive testing, scanning electron microscope and energy dispersive spectrometer. It is found that the linear segregation occurs at the large wall thickness of the casting and/or at the place where the wall thickness is in transition. Segregation element is mainly Cu, which exists as compound θ (Al2Cu) phase. The formation of linear segregation is related to the flow of Cu-rich melt in the late solidification period, while the occurrence of thermal cracks promotes the formation of linear segregation. The formation of linear segregation of the casting can be effectively prevented by eliminating hot spots of the casting, refining crystal grains and increasing solidification speed of the casting.

Synergistic antibacterial effect of green synthesized silver nanoparticles combined with antibiotic on Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) was conducted, resp...

While graph drawing focuses more on the aesthetic representation of node-link diagrams, graph visualization takes into account other visual metaphors making them useful for graph exploration tasks in information visualization and visual analytics. Although there are aesthetic graph drawing criteria that describe how a graph should be presented to make it faster and more reliably explorable, many controlled and uncontrolled empirical user studies flourished over the past years. The goal of them is to uncover how well the human user performs graph-specific tasks, in many cases compared to previously designed graph visualizations. Due to the fact that many parameters in a graph dataset as well as the visual representation of them might be varied and many user studies have been conducted in this space, a state-of-the-art survey is needed to understand evaluation results and findings to inform the future design, research, and application of graph visualizations. In this article, we classify the present literature on the topmost level into graph interpretation, graph memorability, and graph creation where the users with their tasks stand in focus of the evaluation, not the computational aspects. As another outcome of this work, we identify the white spots in this field and sketch ideas for future research directions.

When calculating the position of the sun, earth’s motion can be assumed to be an ellipse if the accuracy of calculation is required to be 0.01 degrees. Then, Kepler’s equation can be applied from the mean anomaly of the sun at a specific time to calculate the true anatomy of the sun at the time, and the sun’s position can be calculated. The average absolute error of calculating the sun’s altitude and azimuth is only 0.04 and 0.06 mrad, respectively, which can meet the requirements of a concentrated solar tracking system. This method only needs to correct the length of the regression year and the near point year for every 100 years, so it can be used for a long time.

In collaboration systems, collaborators often use hand gestures for showing information relating to a distant object. However, in viewer’s perspective, it is sometimes difficult to know where the conventional gesture cue (Hands-in-Air style: HiA) refers to because the conventional HiA gesture appears away from the distant object. In this paper, we investigate how two factors, distance to the object and view angle difference between collaborators, influence the understanding of HiA gesture by comparing the use of it at 25 positions with 5 distances and 5 view angles. In a user study, we found that the distance to the target object and view angle difference negatively influenced HiA gesture communication. The influence of the distance and view angle was more serious between smaller angles (0~30 degree) than larger angles (30~60 degree), and between shorter distances (1m $\sim 1.5\text{m}$ ) than between longer distance (1.5m $\sim 2\text{m}$ ). As a solution, we propose the Hands-on-Target (HoT) style which positions the hand gesture cue on the surface of the target object. The HoT style gesture cue dramatically reduces the negative effect of the distance and view angle difference. Participants completed the task 29.3 percent faster, selected the correct object 2.75 times more, and felt 63.1 percent less mental effort. For further investigation, we discuss on the extensibility of the HoT interface that it can be used not only for object selection but also for diverse type of gesture communication including gesture for object manipulation because the HoT interface can support all possible real world hand gestures.

In this study, TiB + La2O3/Ti-6Al-4V composites were successfully prepared by in situ reaction using selective laser melting technology. The effect of LaB6 content on the fabrication quality, microstructure evolution and mechanical properties of the composite samples was investigated. The results show that the relative density of the sample gradually decreased from 98.56% to 96.57% as LaB6 content increased from 0 wt% to 3 wt%. With increasing LaB6 content, TiB precipitates gradually aggregated and grew from a discrete needle-like structure to a dendritic structure, before eventually developing a cell-like structure. The dislocations piled up around the TiB and La2O3 reinforcements, which impeded the motion of the dislocations and led to the enhancement of the tensile strength of the samples. Different from the addition of a single reinforcement due to the combined strengthening effect of the micrometer-scale and nanoscale reinforcements, the strength of the samples was increased significantly. The Ti-6Al-4V sample with 3 wt% LaB6 addition showed the most significant strengthening effect. Compared to the pure Ti-6Al-4V sample, the 3 wt% LaB6 addition sample gained a 35.71% increase in hardness and a 14.5% increase in tensile strength. Additionally, wear volume was reduced by 47.5%. The results revealed that the addition of LaB6 was a potential way to improve the mechanical performance of the titanium alloys in the additive manufacturing process.

High content rubber modified bitumen (HCRMB) prepared from the high content of waste tire rubber and bitumen has good performance while allowing greater use of the waste tires. However, HCRMB is subject to aging during use, which can affect its performance. The purpose of this paper was to investigate the effect of high content of waste tire rubber and sulfur on the aging behavior of bitumen. The properties of all bitumen were tested using rolling thin film oven aging (RTFOT) test, pressure aging vessel (PAV) test, frequency sweep tests, temperature sweep (TS) test, multiple stress creep recovery (MSCR) test, and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) test. Test results show that the addition of sulfur to HCRMB leads to an improvement in the elasticity of HCRMB. The elasticity of HCRMB with different amounts of sulfur increases with aging. In addition, the increase in the amount of sulfur can improve the RTFOT aging resistance and the PAV aging resistance of HCRMB. Sulfur cannot reduce the degree of oxidation of HCRMB after aging, but can inhibit the degree of desulfurization of HCRMB. Furthermore, the aging process of HCRMB with different amounts of sulfur is dominated by the degradation of polybutadiene.

Asphalt pavements are prone to aging in construction and during service, which can affect the properties of the asphalt. The aging behaviors of high content crumb rubber modified asphalt (HCRMA) were investigated in this paper. The binders were aged in the laboratory and the performances before and after aging were tested using the attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) test, temperature sweep (TS) test, frequency sweep tests, multiple stress creep recovery (MSCR) test, zero shear viscosity (ZSV) test, bending beam rheometer (BBR) test, and linear amplitude sweep (LAS) test. The FTIR test result shows that as the aging progresses, the crumb rubber (CR) continues to undergo desulphurization and degradation reactions in the HCRMA, with the release of substances such as silica and S-C bonded material from the CR into the bituminous phase. The elasticity of HCRMA decreases and then increases as the degree of aging increases. Besides, the low temperature performance of HCRMA is controlled by the stiffness value, and the low temperature stress relaxation properties of HCRMA in the aging process are better than that of 20% content crumb rubber modified asphalt. Moreover, aging can reduce the integrity and fatigue resistance of HCRMA while increasing the compatibility of HCRMA.

Laser powder bed fusion (L-PBF) processed components usually exhibit reduced fatigue performance owing to unavoidable defects at multiple scales, especially when the loading direction is parallel to the building direction. In this study, hot isostatic pressing (HIP) was applied to the L-PBFed Al-4.74Mg-0.70Sc-0.32Zr (wt.%) alloy to enhance the fatigue properties with a focus on the defect (porosities and inclusions) effects, compared with the direct-aged samples. The results demonstrated that HIP induced inconspicuous microstructural effects, but it healed the porosities and promoted oxidation. Therefore, the fatigue crack initiation transformed the oxide-associated porosity into an oxide, with a significant fatigue strength improvement. This study highlights the critical importance of oxides in fatigue performance.

Adverse drug reactions (ADRs) are increasingly becoming a serious public health problem. Spontaneous reporting systems (SRSs) are an important way for many countries to monitor ADRs produced in the clinical use of drugs, and they are the main data source for ADR signal detection. The traditional signal detection methods are based on disproportionality analysis (DPA) and lack the application of data mining technology. In this paper, we selected the spontaneous reports from 2011 to 2018 in Jiangsu Province of China as the research data and used association rules analysis (ARA) to mine signals. We defined some important metrics of the ARA according to the two-dimensional contingency table of ADRs, such as Confidence and Lift, and constructed performance evaluation indicators such as Precision, Recall, and F1 as objective standards. We used experimental methods based on data to objectively determine the optimal thresholds of the corresponding metrics, which, in the best case, are Confidence = 0.007 and Lift = 1. We obtained the average performance of the method through 10-fold cross-validation. The experimental results showed that F1 increased from 31.43% in the MHRA method to 40.38% in the ARA method, this was a significant improvement. To reduce drug risk and provide decision making for drug safety, more data mining methods need to be introduced and applied to ADR signal detection.

Terminal blend rubberized asphalt (TBRA) is widely used as binder of asphalt mixtures due to its technical characteristics of storage stability. However, its road performance deteriorates d...

An accurate flux density calculation is essential for optimizing and designing solar tower systems. Most of the existing methods introduce multiple assumptions, and the accuracy and scope of the application are limited. This paper proposes an integration model used to calculate the flux density distribution after only applying the Gaussian model for solar brightness distribution. It is the first time that multiple reflections and the influence of the optical error transferred from different planes of the glass mirror are considered in order to build an optical model for the flux density of a heliostat. The reflection from two surfaces of the glass mirror used to form three main parts of beams was considered in the present model, and Fresnel’s equations were applied to calculate the energy of the three parts of reflected rays. An elliptic Gaussian model was applied for the optical error distribution of the heliostat. The model error was evaluated using the experimental data of ten heliostats, and the applicability and accuracy of the model were verified through flux distribution and an intercept factor. The average relative prediction error of the present model from the experimental data was only 2.83%, which is less than SolTrace and other models.

The purpose of this paper was to study the aging behaviors of high-viscosity asphalt (HVA). Three kinds of asphalt binders [base asphalt, styrene-butadiene-styrene-modified asphalt (SBSMA),...

The determination of styrene-butadiene-styrene (SBS) content in SBS-modified asphalt (SBSMA) is crucial in road quality control. In this study, a polystyrene (PS)-based index, which is an a...

In-situ ductile dendrite reinforcement is the most effective method to improve the plasticity of bulk metallic glasses. In this study, an in-situ beta phase reinforced Ti/Zr-based bulk metallic glass matrix composite (BMGC), (Ti0.65Zr0.35)90Cu10, was deposited via selective laser melting. Its microstructural characteristics and indentation deformation behaviors were investigated. There were fine and coarse microstructures in the BMGC, due to the existence of heat-affected zone, and they were finer than the microstructures of the BMGCs prepared using traditional technologies; the amorphous and beta phases could be coordinately deformed during the indentation process.

Stress-relief annealing is one of the most frequently used heat treatments for additive manufactured components. The effects of the stress-relief annealing on anodic dissolution behaviour of laser solid formed Ti-6Al-4V in a 15wt.% NaCl electrolyte was investigated. The annealed Ti-6Al-4V exhibited comparatively improved resistance to dissolution compared with as-deposited one. The reduced micro-segregation resulted in the superior corrosion resistance for the annealed Ti-6Al-4V, owing to the formation of a more stable passive film and the weakened galvanic effect. The selective dissolution of α phase was lightened with the decreasing concentration difference of solutes between the refined α and β phases.

Asphalt modification technology is diversifying and developing complexity to overcome early permanent deformation and ensure satisfactory performance for asphalt concrete pavements. The Hamburg Wheel Tracking Device (HWTD) test has been reported to be successful in assessing asphalt mixtures’ rutting performance. This study includes a comprehensive investigation of the effects of different additives at various contents upon the HWTD testing results of asphalt mixtures. According to the degree of their improvement of the rutting performance in the HWTD test, additives were classified into three categories: (1) the first grade including linear styrene–butadiene–styrene (SBS), branched SBS and Gilsonite; (2) the second grade including high-density polyethylene, and polyphosphoric acid; and (3) the third grade including crumb rubber. Additionally, it was found that higher dosages of modifiers do not necessarily result in the improvement of Hamburg performance, and an optimal content exists for most additives. After the extensive mix testing, the dynamic shear rheometer (DSR) testing results were correlated to the HWTD test results in two categories: polymer modified asphalt and non-polymer modified asphalt. It was found that the compliance value Jnr3.2 from the Multiple Stress Creep Recovery (MSCR) test did not underestimate the rutting resistance of polymer modified asphalt compared to non-polymer modified asphalt as the current rutting factor G*/sin δ did. Jnr3.2 was more reliable than G*/sin δ in characterizing the anti-rutting performance of asphalt mixtures no matter they were polymer modified or non-polymer modified. However, different criteria for Jnr3.2 should be adopted for the polymer modified asphalt and non-polymer modified asphalt respectively.

To meet the high temperature and anti-reveling properties required in open-graded friction course, high content polymer modified asphalt (HCPMA) is gradually widely used in China, but the rheological, chemical and aging characteristic is not clear yet. In this paper, HCPMA with different SBS content and different base asphalt are prepared, and Pressure Aging Vessel (PAV) aging was conducted to simulate the long-term aging condition. The chemical and rheological evaluation of HCPMA before and after aging were tracked with Fourier transform infrared, gel permeation chromatography test, dynamic shear oscillatory test, master curve and multiple stress creep and recovery test. The results show that firstly, the aging of HCPMA is combined with hardening of asphalt and degradation of Styrene–butadiene–styrene (SBS) polymer. Furthermore, the addition of high content of SBS polymer can reduce the formation of carbonyl, but the degradation rate of SBS polymer is not related to the content of SBS or the type of base asphalt. Besides, HCPMA with a higher SBS content will have better rheological properties, but in consideration of economy, 9% is optimum dosage. At last, HCPMA prepared with Esso asphalt as base binder exhibits better rheological properties than HCPMA prepared with SK asphalt. However, the rheology difference reduces with the increase of SBS content and after PAV aging.

In the production of terminal blend (TB) rubberized asphalt binder, crumb rubber is digested into asphalt matrix, meanwhile polymers might be added to the degraded rubber/asphalt composite to meet the performance grade criteria. The anti-aging property of TB rubberized asphalt binder is not clear yet. The present study aims to evaluate the aging properties of TB rubberized asphalt binder and TB hybrid binder containing polymeric additive. Fourier transform infrared (FTIR) spectroscopy, Gel permeation chromatography (GPC) and rheological master curve were used to capture the evolution of asphalt binders with aging. The results indicate that TB hybrid binder offers better anti-aging properties than polymer modified asphalt (PMA) with respect to asphalt oxidation and polymer degradation. The presence of nano-silica component in TB rubberized asphalt is considered to improve the anti-aging property. The polymer molecular weight retention index retrieved from GPC test and phase angle difference determined from phase angle master curve are connected with each other. These two methods are very promising in evaluating polymer degradation behavior of PMA.

In this study, Ti 6Al 4V was fabricated via wire and arc additive manufacturing (WAAM) using different deposition strategies. The effects of the travel direction and interlayer dwell time on the evolution of the prior-β grain morphology, microstructure, microhardness, and room-temperature tensile properties of the as-deposited walls were systematically investigated. The thermal and stress/strain field during the deposition process were also simulated to elucidate the macro/microstructural evolution during the deposition. When the interlayer dwell time was less than 24 s, there was a transition from equiaxed prior-β grains (EBGs) to columnar prior-β grains (CBGs) from the bottom to the top of the deposited wall. Vertical and tilted CBGs were obtained with bidirectional and unidirectional travel directions, respectively. With a dwell time of 120 s and unidirectional travel directions, full-equiaxed prior-β grains were obtained within the wall. The EBGs were formed not from the solidification of the molten pool but from the recrystallization induced by the large heat accumulation and high stress/strain during the WAAM process. The recrystallization nucleation rate of the EBG zone was the highest with a dwell time of 24 s. There were tilted layer bands when bidirectional travel strategies were used. There was a fine lamellar α in the layer band-free region and a basketweave α in the layer band region. The increase in the interlayer dwell time led to a decrease in the width of the α lath in the layer band region, but little changed in the layer band-free region. In addition, the hardness, yield strength, and tensile strength increased with the increase in the dwell time from 0 to 120 s.