Search

This study aimed to evaluate the association between polymyxin B (PMB) exposure and acute kidney injury (AKI) and analyze the risk factors for PMB‐induced AKI in critically ill patients. Plasma concentrations of PMB were determined using an ultraperformance liquid chromatography–tandem mass spectrometer in intensive care unit patients who were administered PMB. Univariate and multivariate analyses were conducted to identify risk factors. A receiver operating characteristic curve was constructed to assess the discriminant power of the factors and to identify the cutoff value for AKI. The white blood cell count and estimated area under the concentration–time curve (AUC) of patients administered PMB were independent risk factors for PMB‐induced AKI, where AUC were calculated using a first‐order pharmacokinetic equation based on the mid‐dosing interval concentration (C1/2t) and peak concentration. The area under the receiver operating characteristic curve of the final model was 0.805 (95% confidence interval, 0.690–0.921). The cutoff value for the combined predictor was 0.57. Alternatively, when using C1/2t, which was strongly correlated with AUC, as the only independent risk factor, the analysis showed that the 3.47 μg/ml threshold provides favorable differentiation between the AKI and non‐AKI groups. These results provide insightful information for therapeutic drug monitoring–guiding PMB dosing in clinical practice. [ABSTRACT FROM AUTHOR]

Hierarchical zeolites have attracted more and more attention due to their excellent diffusion and mass transfer performance. However, synthesis of most hierarchical zeolites requires long-chain organic templates, which could increase preparation cost. Here, hierarchical ZSM-5 zeolites were successfully prepared with simple organic templates (triethylenetetramine) in a rotating oven. Besides hierarchical structure, the crystal size of ZSM-5 also decreased when they were synthesized under dynamic hydrothermal conditions. The samples were analyzed using various physicochemical characterizations, such as X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR), temperature-programmed desorption of ammonia (NH3-TPD) and N2 adsorption–desorption. The hierarchical ZSM-5 zeolites synthesized in a rotating oven presented better catalytic activity and stability in iso-butane cracking reaction than those synthesized under conventional static hydrothermal conditions. [ABSTRACT FROM AUTHOR]

• Evolutionary trend of cryogenic thermal conductivity of CFRP laminate is revealed. • Lay-up angle shows no effect on out-of-plane thermal conductivity. • A theoretical model is developed to evaluate the effect of stacking sequence. Carbon fiber reinforced polymer (CFRP) composites with excellent mechanical properties and low thermal conductivity are promising materials for cryogenic facility support structures. However, the temperature dependence and stacking sequence dependence of the laminates' thermal conductivities challenge their thermo-mechanical design. Previous work dealing with the cryogenic thermal conductivity of laminates was relatively inadequate, and the effect of stacking sequence has not been sufficiently clarified. Herein, the cryogenic thermal conductivity of CFRP composite was investigated, and a theoretical model for the out-of-plane thermal conductivity of laminate was developed. To this end, the thermal conductivities of epoxy resin and laminates were measured at temperatures from 20 K to 293 K. The cryogenic thermal conductivity of carbon fiber was then extrapolated. Subsequently, a theoretical model was developed based on the thermal-electrical analogy method to evaluate the effect of stacking sequence. The obtained model was then validated by numerical analysis and experimental work. Lastly, the effects of lay-up angles and component properties on out-of-plane conductivity were examined. The test results suggested longitudinal thermal conductivity of composites exhibiting significant temperature dependence, with a decreasing trend recorded from 6.317 Wm−1K−1 to 0.355 Wm−1K−1 and transverse thermal conductivity decline from 0.626 Wm−1K−1 to 0.156 Wm−1K−1. The theoretical analysis indicated that the stacking sequence could reduce the out-of-face thermal conductivity by up to approximately 6.5 %, while the lay-up angle did not show any influence. In sum, novel insights into the cryogenic thermal conductivity of CFRP composites were provided, with guidance for the design and analysis of CFRP composites in cryogenic applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Purpose: To assess the pharmacokinetics and pharmacodynamics of linezolid in a retrospective cohort of hospitalized Chinese older patients.Patients > 60 years of age, who received intravenous linezolid (600 mg), were included. A population pharmacokinetics (PPK) model was established using nonlinear mixed-effects modeling. The predictive performance of the final model was assessed using goodness-of-fit plots, bootstrap analyses, and visual predictive checks. Monte Carlo simulations were used to evaluate the achievement of a pharmacodynamics target for the area under the serum concentration–time curve/minimum inhibitory concentration (AUC0–24/MIC).A total of 210 samples were collected from 120 patients. A one-compartment PPK model with linear elimination best predicted the linezolid plasma concentrations. Linezolid clearance (CL) was 4.22 L h−1 and volume of distribution (Vd) was 45.80 L; serum uric acid (SUA) was a significant covariate of CL.The results of this study indicated that the standard dose was associated with a risk of overexposure in older patients, particularly those with high SUA values; these patients would benefit from a lower dose (300 mg every 12 h).Methods: To assess the pharmacokinetics and pharmacodynamics of linezolid in a retrospective cohort of hospitalized Chinese older patients.Patients > 60 years of age, who received intravenous linezolid (600 mg), were included. A population pharmacokinetics (PPK) model was established using nonlinear mixed-effects modeling. The predictive performance of the final model was assessed using goodness-of-fit plots, bootstrap analyses, and visual predictive checks. Monte Carlo simulations were used to evaluate the achievement of a pharmacodynamics target for the area under the serum concentration–time curve/minimum inhibitory concentration (AUC0–24/MIC).A total of 210 samples were collected from 120 patients. A one-compartment PPK model with linear elimination best predicted the linezolid plasma concentrations. Linezolid clearance (CL) was 4.22 L h−1 and volume of distribution (Vd) was 45.80 L; serum uric acid (SUA) was a significant covariate of CL.The results of this study indicated that the standard dose was associated with a risk of overexposure in older patients, particularly those with high SUA values; these patients would benefit from a lower dose (300 mg every 12 h).Results: To assess the pharmacokinetics and pharmacodynamics of linezolid in a retrospective cohort of hospitalized Chinese older patients.Patients > 60 years of age, who received intravenous linezolid (600 mg), were included. A population pharmacokinetics (PPK) model was established using nonlinear mixed-effects modeling. The predictive performance of the final model was assessed using goodness-of-fit plots, bootstrap analyses, and visual predictive checks. Monte Carlo simulations were used to evaluate the achievement of a pharmacodynamics target for the area under the serum concentration–time curve/minimum inhibitory concentration (AUC0–24/MIC).A total of 210 samples were collected from 120 patients. A one-compartment PPK model with linear elimination best predicted the linezolid plasma concentrations. Linezolid clearance (CL) was 4.22 L h−1 and volume of distribution (Vd) was 45.80 L; serum uric acid (SUA) was a significant covariate of CL.The results of this study indicated that the standard dose was associated with a risk of overexposure in older patients, particularly those with high SUA values; these patients would benefit from a lower dose (300 mg every 12 h).Conclusion: To assess the pharmacokinetics and pharmacodynamics of linezolid in a retrospective cohort of hospitalized Chinese older patients.Patients > 60 years of age, who received intravenous linezolid (600 mg), were included. A population pharmacokinetics (PPK) model was established using nonlinear mixed-effects modeling. The predictive performance of the final model was assessed using goodness-of-fit plots, bootstrap analyses, and visual predictive checks. Monte Carlo simulations were used to evaluate the achievement of a pharmacodynamics target for the area under the serum concentration–time curve/minimum inhibitory concentration (AUC0–24/MIC).A total of 210 samples were collected from 120 patients. A one-compartment PPK model with linear elimination best predicted the linezolid plasma concentrations. Linezolid clearance (CL) was 4.22 L h−1 and volume of distribution (Vd) was 45.80 L; serum uric acid (SUA) was a significant covariate of CL.The results of this study indicated that the standard dose was associated with a risk of overexposure in older patients, particularly those with high SUA values; these patients would benefit from a lower dose (300 mg every 12 h). [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymer (CFRP) composites possess excellent properties suitable for use in spacecraft liquid fuel tanks. However, the cryogenic reliability of composites remains challenging owing to the variation in mechanical responses under cryogenic environments. So far, most previous studies have focused on the cryogenic properties of composites, and little has been devoted to the cryogenic damage behaviors of laminates. Herein, the cryogenic damage evolution of CFRP laminates was investigated by micro-computed tomography (μCT) characterization and micromechanical analysis for the first time. To this end , in-situ μCT tensile tests for quasi-isotropic CFRP laminates were conducted at temperatures of 293 K, 193 K, and 93 K, and the observed cryogenic damage characteristics were analyzed. A micromechanical computational model was then developed, and the temperature-dependent constitutive model of epoxy resin was utilized to investigate the cryogenic damage evolution process of laminates. The effects of matrix property variation and thermal stresses on the cryogenic damage of laminates were examined, and the cryogenic fracture toughness for transverse cracking was deduced. The characterization results revealed a significantly increased damage volume fraction of laminates from 0.65% to 1.56% at cryogenic temperatures, mainly originating from the increased delamination (from 0.08% to 0.54%) and 90° ply transverse cracks (from 0.48% to 0.87%). The numerical analyses indicated the cryogenic brittle transition of the matrix as the primary factor responsible for the delamination, while the transverse cracks were influenced by matrix properties and thermal stresses. This study provides critical insight into the cryogenic damage behavior of CFRP laminates, essential for cryogenic applications of composites. [Display omitted] • Cryogenic damage evolution of CFRP laminates is characterized for the first time. • Cryogenic in-situ micro-computed tomography characterization is conducted. • A micromechanical model is developed for cryogenic damage behavior of laminate. • Mechanism of cryogenic effect on laminate damage behavior is revealed. [ABSTRACT FROM AUTHOR]

Among ceramic matrix composites (CMCs), carbon fiber-reinforced silicon carbide matrix (C/SiC) composites are widely used in numerous high-temperature structural applications because of their superior properties. The fiber–matrix (FM) interface is a decisive constituent to ensure material integrity and efficient crack deflection. Therefore, there is a critical need to study the mechanical properties of the FM interface in applications of C/SiC composites. In this study, tensile tests were conducted to evaluate the interfacial debonding stress on unidirectional C/SiC composites with fibers oriented perpendicularly to the loading direction in order to perfectly open the interfaces. The characteristics of the material damage behaviors in the tensile tests were successfully detected and distinguished using the acoustic emission (AE) technique. The relationships between the damage behaviors and features of AE signals were investigated. The results showed that there were obviously three damage stages, including the initiation and growth of cracks, FM interfacial debonding, and large-scale development and bridging of cracks, which finally resulted in material failure in the transverse tensile tests of unidirectional C/SiC composites. The frequency components distributed around 92.5 kHz were dominated by matrix damage and failure, and the high-frequency components distributed around 175.5 kHz were dominated by FM interfacial debonding. Based on the stress and strain versus time curves, the average interfacial debonding stress of the unidirectional C/SiC composites was approximately 1.91 MPa. Furthermore, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDXS) were used to observe the morphologies and analyze the chemical compositions of the fractured surfaces. The results confirmed that the fiber was completely debonded from a matrix on the fractured surface. The damage behaviors of the C/SiC composites were mainly the syntheses of matrix cracking, fiber breakage, and FM interfacial debonding. [ABSTRACT FROM AUTHOR]

Abstract As one of the ceramic matrix composites (CMCs), carbon fiber-reinforced silicon carbide matrix (C/SiC) composites are promising materials used in various engineering applications owing to their superior properties. Precision surface grinding has been widely applied in the machining of CMC composites; however, the material removal mechanisms of C/SiC composites have not been fully elucidated yet. To reveal the material removal mechanisms in the grinding of chemical vapor infiltration-fabricated C/SiC composites, novel single-abrasive scratch tests were designed and conducted in two typical cutting directions. The experimental parameters, especially the cutting speed, conformed to the actual grinding process. The results show that the grinding parameters (feed rate, spindle speed, depth of cut, and cutting direction) have significant influences on the grinding forces, surface integrity, and affected subsurface region. The tangential force is in general larger than the normal force at the same cutting depth. Furthermore, both the tangential and normal forces in the longitudinal cutting direction are larger than those in the transverse cutting direction. The impacts and abrasive actions at the tool tip mainly caused the material removal. The predominant material removal mode is brittle fracture in the grinding of unidirectional C/SiC composites, because the damage behaviors of the C/SiC composites are mainly the syntheses of matrix cracking, fiber breakage, and fiber/matrix interfacial debonding. These results are rationalized based on the composite properties and microstructural damage features. [ABSTRACT FROM AUTHOR]

Edge surface grinding has been widely applied in achieving functional surfaces and repairing the damage surfaces of carbon fiber-reinforced plastic (CFRP) composites especially with complex three-dimensional features. The conventional surface grinding (CSG) usually generates surface damages, leading to reduced service life and load-carrying capability of the parts. Therefore, there is a critical need to develop a surface grinding process of CFRP composites in a high-quality and high-efficiency way. Rotary ultrasonic machining (RUM) surface grinding has been proven to be such a process. In addition, RUM edge surface grinding can be conducted by up surface grinding or down surface grinding. However, the difference between up surface grinding and down surface grinding with RUM has not been reported. In this paper, the comparison between up surface grinding and down surface grinding with RUM is studied for the first time. The effects of the grinding parameters on machining performance, including cutting force, surface roughness, and surface morphology characteristics, are experimentally studied. The results show that the cutting forces in up grinding are obviously larger than those in down grinding. Lower surface roughness is generated by down grinding when grinding parameters are kept unchanged. The reasons for the differences of cutting forces and surface integrity are discussed. Surface morphologies suggest clearly that brittle fracture is the predominant material removal mode in grinding of CFRP composites. The chip size of the resin, the fracture size of the carbon fiber, and the material removal scale are smaller in down grinding. Furthermore, compared with CSG, the advantages of RUM surface grinding are presented. This investigation will provide useful guidance for surface grinding of CFRP composites. [ABSTRACT FROM AUTHOR]

An investigation of vibration characteristics on adhesively bonded lap joints which considers the damping property of the adhesive layer is presented. For this purpose, a layer-wise plate finite element method is proposed and extended to model the lap joint. By imposing some additional virtual boundary conditions on the joint structure, the lap joint can be treated as a special sandwich plate, which can be hence modeled by the present method. The applicability of the present modeling method is verified through comparison with the numerical data obtained by traditional solid finite element for a functionally graded single lap joint and a two-step lap joint. Finally, a parametric study following the proposed method is also conducted to evaluate the effect of the adhesive loss factor, the overlap area, the adhesive thickness, the step height ratio and step number on the modal frequency and its corresponding modal loss factor. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymer (CFRP) composites have widely been used in the aerospace field owing to their excellent mechanical properties. However, composite structures often fail under complex space environmental conditions. In particular, the fiber bridging and cryogenic temperature may greatly change the fracture toughness of CFRP composites. Herein, the effects of cryogenic temperature and fiber bridging on the fracture toughness of unidirectional composite laminates were experimentally examined by double cantilever beam (DCB) testing at different temperatures (room temperature, −50 °C, −70 °C, −100 °C, −150 °C, and −180 °C). Different calculation methods of fracture toughness were used and the results were compared. A method without measuring the delamination length at low temperatures was used and the results were consistent with other methods. The average difference in fracture toughness values was less than 5 %. The fiber-bridging microstructures of composites under cryogenic temperatures were examined by confocal microscopy along with the geometric morphology and parameters of surface roughness. The results suggested changes in the matrix failure mechanism at −50 °C, resulting in maximum fracture toughness, which is 26.45 % higher than that at room temperature. A semi-analytic approach was then proposed to express the bridge stress, and a bilinear cohesive zone model was established to simulate the delamination of composite laminates at low temperatures. Overall, the numerical data agreed well with the experimental results (peak force maximum error of 17 %), suggesting the usefulness of the proposed method for the prediction of interlamination properties and structural damage design of composite structures at cryogenic temperature. [Display omitted] • In-situ double cantilever beam (DCB) testing is conducted under cryogenic temperatures. • A semi-analytic DCB model is developed by considering fiber bridging effect. • Failure modes of carbon fiber-reinforced polymer laminates under various temperatures are discussed. [ABSTRACT FROM AUTHOR]

• The actual material removal mechanisms in RUSM of CFRP are investigated. • Both the ductile and the brittle fracture removal modes are observed and identified. • The material removal mode of CFRP is changed with the scratching depth increasing. • The effects of ultrasonic power on scratching forces are discussed. • The effects of ultrasonic power on delamination are analyzed and discussed. Rotary ultrasonic machining has been successfully explored in surface machining of carbon fiber reinforced plastic (CFRP) composites. It has been proven to be an effective and efficient CFRP machining method. Both theoretical and experimental investigations have been conducted with the assumption that the CFRP is removed by brittle fracture removal mode. However, in brittle material machining, ductile flow phenomenon still exists. Ductile scratching marks are also observed on the machined CFRP surfaces. It is still unknown that what actual material removal modes are under different machining variables. To investigate the material removal mechanisms in rotary ultrasonic surface machining (RUSM) of CFRP, single abrasive scratching tests were conducted. The scratching induced characteristics and scratching forces were analyzed. Both the ductile removal mode and the brittle fracture removal mode were observed and identified in both carbon fiber layers and epoxy resin layers on the machined marks by using scanning electron microscopy (SEM) imaging. With the increase of scratching depth, the material removal mode of CFRP was changed from the ductile removal mode to the brittle fracture mode. From the analysis of kinematic trajectory of diamond grain, the scratching cutting forces were decreased in the tests with the assistance of ultrasonic vibration under the same machining variables. The generation mechanisms of the delamination were analyzed and discussed. [ABSTRACT FROM AUTHOR]

The peer-to-peer-based video resource dissemination is important for handling extreme conditions such as flash crowds which severely break the balance between supply and demand of video content and bring negative effects for quality of service (QoS). In this paper, we propose a novel interest detection-based video dissemination algorithm under flash crowd in mobile ad hoc networks (IDVD). IDVD classifies the user behavior of requesting video content in terms of the popularities and playback time of video and considers the demand of popular video as the cause of flash crowd. IDVD makes use of the prediction of necessary bandwidth and period time of intensive request to be aware of period time and scale of flash crowd. IDVD employs a resource dissemination algorithm which can fast discover interested nodes and achieve the on-demand dissemination of video resources in neighboring geographical area, in order to handle imbalance between supply and demand. IDVD uses the epidemic model to describe the state transition of nodes and define the convergence condition of resource dissemination algorithm. Extensive tests show how IDVD achieves much better performance results in comparison with other state of the art solutions. [ABSTRACT FROM AUTHOR]

Wuzhi capsule (WZC), a commonly used Chinese patent medicine to treat various types of liver dysfunction in China, increases the exposure of tacrolimus (TAC) in liver transplant recipients. However, this interaction has inter-individual variability, and the underlying mechanism remains unclear. Current research indicates that CYP3A4/5 and drug transporters influence the disposal of both drugs. This study aims to evaluate the association between TAC dose-adjusted trough concentration (C/D) and specific genetic polymorphisms of CYP3A4/5 , drug transporters and pregnane x receptor (PXR), and plasma levels of major WZC components, deoxyschisandrin and γ-schisandrin, in liver transplant patients receiving both TAC and WZC. Liquid chromatography-tandem-mass spectrometry was used to detect the plasma levels of deoxyschisandrin and γ-schisandrin, and nine polymorphisms related to metabolic enzymes, transporters and PXR were genotyped by sequencing. A linear mixed model was utilized to assess the impact of the interaction between genetic variations and WZC components on TAC lnC/D. Our results indicate a significant association of TAC lnC/D with the plasma levels of deoxyschisandrin and γ-schisandrin. Univariate analysis demonstrated three polymorphisms in the genes ABCB1 (rs2032582), ABCC2 (rs2273697), ABCC2 (rs3740066), and PXR (rs3842689) interact with both deoxyschisandrin and γ-schisandrin, influencing the TAC lnC/D. In multiple regression model analysis, the interactions between deoxyschisandrin and both ABCB1 (rs2032582) and ABCC2 (rs3740066), post-operative day (β < 0.001, p < 0.001), proton pump inhibitor use (β = −0.152, p = 0.008), body mass index (β = 0.057, p < 0.001), and ABCC2 (rs717620, β = −0.563, p = 0.041), were identified as significant factors of TAC lnC/D, accounting for 47.89% of the inter-individual variation. In summary, this study elucidates the influence of the interaction between ABCB1 and ABCC2 polymorphisms with WZC on TAC lnC/D. These findings offer a scientific basis for their clinical interaction, potentially aiding in the individualized management of TAC therapy in liver transplant patients. • Deoxyschisandrin is the main component of WZC to increase TAC lnC/D. • ABCs transporter polymorphisms modulate the pharmacokinetics of TAC. • Interaction between deoxyschisandrin and ABCs polymorphisms in regulating TAC lnC/D. • Combining gene polymorphisms and deoxyschisandrin helps to adjust the dose of WZC. • Helps understand postoperative medications in liver transplant patients. [ABSTRACT FROM AUTHOR]

This paper details the application of the finite element model, Bayesian regularized neural network, and genetic algorithm for metallic thermal protection system parameter optimization. The object is to minimize the structure weight and satisfy multiple performance constraints which consist of the deformation of the top face sheet, the stress around the lug hole, the stress of the honeycomb core, and the inner temperature. Firstly, a high-fidelity thermo-mechanical coupled finite element model was established to investigate the thermal and mechanical properties of the metallic thermal protection system. Then, surrogate models were constructed based on the Bayesian regularized neural network which assigns a probabilistic nature to the network weights and biases and allows the network automatically and optimally penalize complex models. To guarantee full exploration of the design space, an optimal orthogonal-maximin Latin hypercube design was adopted and modified to generate preliminary sampling points. Finally, an approach for genetic algorithm constraint handling, stochastic ranking, was introduced and modified by multiple constraint ranking to handle constraints. In addition, a sensitivity analysis was performed to disclose the effects of individual design variables on the thermal and mechanical responses. The results indicate that the structure mass is decreased by 41.2 % when compared to the initial design and all the constraints are satisfied. [ABSTRACT FROM AUTHOR]

The superior properties make carbon fiber-reinforced plastic (CFRP) composites attractive in many applications. After CFRPs’ molding processes, additional machining processes are needed to produce final functional shapes with dimensional precision. Edge trimming is the primary process to cut the edge of CFRP composites. To reduce or further solve the problems in traditional machining processes, edge trimming of CFRP composites with rotary ultrasonic machining (RUM) has been proposed and conducted in this investigation. In RUM edge trimming processes, two different tool orientations (RUM edge trimming with tool end face and RUM edge trimming with tool side face) can be performed. The comparisons of machining performance and machined surface quality between these two different RUM edge trimming processes have been conducted. Smaller ultrasonic vibration amplitude in RUM using tool end face or larger ultrasonic vibration amplitude in RUM using tool side face produces smaller surface roughness. Lower feeding-directional cutting force, lower normal cutting force, and lower resultant force are generated in the process using tool side face. RUM using tool end face produces smaller surface roughness, smaller debris width, microcracking, flowed matrix on machined CFRP surfaces, etc. [ABSTRACT FROM AUTHOR]

Laser additive manufactured zirconia-alumina ceramic (ZrO 2 -Al 2 O 3 ) parts demonstrate severe problems resulting from cracking and inhomogeneous material dispersion. To reduce these problems, we propose a novel ultrasonic vibration-assisted laser engineered net shaping (LENS) process for fabrication of bulk ZrO 2 -Al 2 O 3 parts. Results showed that the initiation of cracks and the crack propagation were suppressed in the parts fabricated by LENS process with ultrasonic vibration. For the parts fabricated without ultrasonic vibration, the sizes of cracks decreased with the increase of laser power. Scanning electron microscope analyses proved that the introduction of ultrasonic vibration was beneficial for grain refinement and uniform material dispersion. Due to the suppressed cracking, refined grains, and homogenized material dispersion, the parts fabricated with ultrasonic vibration demonstrated better mechanical properties (including higher microhardness, higher wear resistance, and better compressive properties), compared with the parts fabricated without ultrasonic vibration. [ABSTRACT FROM AUTHOR]

Although TiB reinforced titanium matrix (TiB-Ti) composites exhibit superior wear resistance and strength, they still demonstrate severe problems resulted from lowered toughness and ductility, as compared with titanium and its alloys. To reduce these problems, this paper tailors a three-dimensional quasi-continuous network (3DQCN) microstructure within TiB-Ti composites by in-situ laser deposition-additive manufacturing process. Results show that the laser power has great impacts on the formation of 3DQCN microstructure and the 3DQCN microstructure is beneficial to both strengthening and toughening effects on TiB-Ti composites. To have a quantitative understanding of strengthening effects, this paper, for the first time, has modeled the yield strength of TiB-Ti composites with 3DQCN microstructure. [ABSTRACT FROM AUTHOR]

• Sediment load from January to December all showed downward trends during 2003–2017. • Monthly sediment load dynamics was dominated by 3-, 5- and 12-months oscillations. • Relationships between monthly sediment loads and pertinent factors differed with timescale. • MEMD method can well handle non-stationary and nonlinear hydrological processes. At different time scales, the potential factors influencing changes in sediment transport vary. Because the processes of each impact factor overlaps on different time scales, it is challenging to evaluate the complex multi-scale relationships between monthly sediment load and its potential impact factors. The objective of this study was to investigate the scale-specific main factors influencing monthly sediment loads using the multivariate empirical mode decomposition (MEMD) method. Monthly sediment loads and five potential influencing factors (runoff, precipitation, air temperature, potential evapotranspiration, and enhanced vegetation index) during 2003–2017 were collected in the Wujiang karst watershed of southwest China. The MEMD method was used to decompose the temporal series of monthly sediment load into seven intrinsic mode functions (IMF) and residuals using a Hilbert transform. The sum of variance contribution rates of IMF1 (3.2 months), IMF2 (5.5 months) and IMF3 (12.1 months) was more than 90%. Although temperature and potential evapotranspiration significantly affect monthly sediment loads at the observation scale, no significant relationships were observed between them at some specific scales after MEMD. The accuracy of the prediction model after MEMD was better than that of the prediction model using original data. Runoff and precipitation were important predictors in the prediction model. This study shows the advantages of the MEMD method for analyzing non-stationary and nonlinear hydrological processes, and this useful tool is recommended for application in other karst watersheds. [ABSTRACT FROM AUTHOR]

Abstract: Temperature generates in micro-scale cutting process has a great effect on cutting performance due to centralized heat generation. In this study, a set of micro-cutting experiments (8μm/r≤f≤50μm/r) were carried out to measure temperatures in micro-cutting process with high accuracy. A fast-response thermocouple with a property of self-renewing was installed in a cylinder workpiece to measure the temperatures of workpiece and tool tip simultaneously. In each test, temperature of the workpiece surface is obtained just before the hot junction of thermocouple is machined. When the hot junction is machined, the tested maximum temperature is recognized as the temperature of tool tip. In parallel, an energy density-based ductile failure material model is developed to simulate the micro-cutting process by finite element method. In simulation, when mesh distribution is changed, the predicted forces with same energy density G ε are closer to the forces at original mesh distribution than those predicted by same energy G f . Consequently, the energy density-based ductile failure material model can reduce mesh dependence in different mesh distribution conditions. Under new mesh distribution, Temperatures of the workpiece surface and tool tip are identified in the predicted micro-cutting temperature field. The predicted micro-cutting temperatures of workpiece surface and tool tip are very close to the experimental results. Further, the variation of temperature and its relationship with chip curling are also discussed. [Copyright &y& Elsevier]