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Tropospheric ozone significantly damages vegetation and reduces net primary productivity (NPP). We developed a stable linear NPP response model based on accumulated ozone exposure over a threshold of 40 parts per billion (ppb) (AOT40). We then estimated the effects of regional ozone damage on NPP for different vegetation types. The study suggests an average decrease in NPP of 24.7% due to ozone pollution in the North China Plain, similar to previous estimates ranging from 10.1% to 24.7%, with a maximum reduction exceeding 200 [g C m‐2 yr‐1] and more than 50%. Vegetation types such as broadleaf forests, needleleaf forest, crops, and grasses showed significant NPP decreases of 47.1%, 37.8%, 36.7%, and 44.6%, respectively. Declining NPP also had negative impacts on several Chinese crop species. Our work highlights the need for urgent and effective action to mitigate ozone pollution's substantial detrimental effects on ecosystem health and productivity. Plain Language Summary: Ozone pollution led to an average 25% decrease in net primary productivity in the North China Plain. This decline is consistent with previous estimates that ranged from 10% to 25%. Productivity of forest trees, crops, and grasses declined significantly, ranging from 36.7% to 47.1%. These results have implications for Chinese crops, as lower crop productivity can negatively affect crop yields. Our study highlights the urgent need for action to mitigate the detrimental effects of ozone pollution on ecosystem health and productivity. Key Points: We developed a stable model to estimate ozone impact on the productivity of plants'Ozone pollution resulted in an average decline in productivity of 25% per year in all ecosystem types in the North China Plain regionOzone pollution led to net primary productivity declines in forest, crops, and grasses, with reductions ranging from 36.7% to 47.1% [ABSTRACT FROM AUTHOR]

PTFE/Al/W granular composite is a kind of impact-initiated energetic material and may well enhance damage to the impacted targets. To gain insight into response behavior of PTFE/Al/W granular composite under different loadings, the combined approach of experiments and theoretical analyses is used in this paper. More specifically, the combinations of quasi-static compression, dynamic tests, and ballistic impact experiments are conducted. Cylindrical PTFE/Al/W granular composite specimens, with a density of 7.7 g/cm 3 and a diameter of 10 mm, are fabricated by cold press molding, sintering, and cooling. Moreover, a high-speed imaging technique is used to record response process of the specimens in ballistic impact experiments. The experimental and analytical results show that the response behavior of PTFE/Al/W granular composite is significantly influenced by the loading strain rate. When the strain rate is less than 3.6 × 10 3 s - 1 , only mechanical response is observed in the quasi-static compression and dynamic tests. However, when the strain rate is higher than 4 × 10 4 s - 1 , the chemical reaction is found in the ballistic impact experiments. Furthermore, chemical response shows an enhanced trend with increasing of the loading strain rate. [ABSTRACT FROM AUTHOR]

To realize the resource utilization of waste mask fibers (MF), a layer of ZnS nanoparticles was grown on MF by a one-step hydrothermal method, and a MF/ZnS sensor was successfully prepared. This is the first time that resource utilization of MF has been combined with the development of a high-performance gas sensor. The MF/ZnS sensor showed high sensitivity and recoverability to target vapors at room temperature. Compared with ZnS powder loaded on a ceramic substrate, the MF/ZnS composite responses to four analytes have been improved by 8.4~35.2 times. In addition, the time for the MF/ZnS sensor to complete one response–recovery cycle for all four analytes was less than 30 s. This should be attributed to the high gas permeability of the MF substrate, which made the ZnS particles loaded on the MF more fully exposed to contact with the target vapors. This work not only provides a simple and low-cost method to optimize the sensing performance of gas sensors but also provides a new way for the resource utilization of MF. [ABSTRACT FROM AUTHOR]

This paper reports the findings of the experimental and numerical study on the mechanical behaviour of the normal aggregate concrete filled steel tube (NACFST) and the recycled aggregate concrete filled steel tube (RACFST) columns strengthened with carbon fibre reinforced plastic (CFRP) subjected to axial concentric and eccentric loadings. The study was carried out to examine the influence of the tube thickness, the concrete type, the CFRP reinforcement and the load eccentricity on the compressive behaviour of RACFST. Simple finite element models were then developed to simulate the compressive behaviour of both RACFST and NACFST columns, with good correlation to the experimental results in terms of load–displacement traces and deformation modes. The results indicate that both RACFST and NACFST specimens have a similar deformation mode, with the axial compression capacity of RACFST specimens only slightly lower than that of NACFST. The comparisons of the calculations from the standards of American Concrete Institute (ACI), Australian (AS) and Eurocodes (EC4) show that ACI and AS are more conservative than EC4. Furthermore, the modified models are proposed, which provide good predictions of the peak load for the columns strengthened with CFRP under both concentric and eccentric axial loadings, to offer a necessary help to the relevant designs. [ABSTRACT FROM AUTHOR]

A novel method is presented for the production of the 6 + 1 filament MgB2 wires using internal Mg diffusion (IMD) process. For the MgB2 long wire with 1.4-mm diameter produced by graphene-coated Nb addition, the critical current (Ic) is about 1000 A at 4 T and 4.2 K, which is 2.5 times higher than that of the undoped sample. The increased Ic is attributed to the enhanced flux pinning force and improved grain connectivity. The obtained results show that graphene-coated Nb addition MgB2 wires have excellent superconductivity and mechanical property compared with the conventional PIT wires in practical application. [ABSTRACT FROM AUTHOR]

In view of the sparse, uneven distribution and poor data continuity of measured soil moisture sites in China and the lack of large-scale research, the soil moisture data set of the European Space Agency (ESA) Climate Change Initiative (CCI) was applied to carry out spatial-temporal variation analysis of soil moisture in five agricultural ecological zones in Northern China. The Pearson correlation coefficient and multiple component metric Kling--Gupta efficiency were used to verify the validity of remote sensing data and to analyze the temporal and spatial variation of soil moisture with the concept of temporal and spatial persistence. The ESA CCI remote sensing soil moisture data had good spatial and temporal adaptability for the whole year in the Huang- Huai-Hai region, in summer in Northeast China, in spring in Northwest China, in summer and autumn in the Loess Plateau, and in summer and autumn in the Inner Mongolian Plateau. The annual mean soil volume water content in Northern China from 1991 to 2016 was 0.06-0.39 m³ m-3. Spatially, soil moisture in Northern China has been gradually increasing from west to east. In this area, seasonally, soil moisture was the highest in summer, followed by autumn and then winter and spring. Northeast China, the Loess Plateau, and the Huang-Huai-Hai region are important grain-producing areas in China. The soil moisture in these areas fluctuates widely with seasonal changes and shows an obvious drying trend. [ABSTRACT FROM AUTHOR]

This paper presents 3D nonlinear finite element analyses on concrete-filled steel-tube (CFST) columns subjected to lateral impact loading by considering concrete type, projectile configuration, and strengthening with carbon fiber-reinforced polymer (CFRP) laminates. The numerical outputs were validated against the experimental results with good agreement, in terms of load-displacement trace and deformation mode. Using the validated models, further studies were undertaken to examine the influence of various parameters on the impact response, which include the material property, D/t (external diameter/wall thickness) ratios, and CFRP coverage area. The numerical predictions show that increasing the impact energy enables the columns to exhibit a higher impact force for all CFST columns studied. Reducing the D/t ratio and increasing the steel-tube strength led to an increase of the impact force and a decrease of the displacement, due to the enhanced stiffness of the tube. The results also indicate that increasing the CFRP wrapping from one-third coverage of the column surface to two-third coverage increases the impact peak load and columns stiffness but reduces the lateral displacement, while the full CFRP wrapping has almost the same enhancement as does the two-third coverage. [ABSTRACT FROM AUTHOR]

In this work, practical kilometer-length 18- and 30-filament Monel/Nb/MgB2 wires have been prepared by in situ powder-in-tube (PIT) method, combing in the twisting of wires with twisting pitches (TP) of 5 mm, 10 mm, and 20 mm. Transport critical current density (Jc) properties at various temperatures and magnetic fields for MgB2 wires with different TP and the effects of the heat-treatment conditions and wire diameter size on the Jc of 30- filament wire have been investigated in detail. The results suggest the Jc of MgB2 wire without twisting at 4.2 K, 4 T, and 20 K, 3 T separately reaches 1.9 × 105 and 5.87 × 104 A/cm2 for 30-filament wire, and 1.48 × 105 and 4.4 × 104 A/cm2 for 18-filament wire. After twisting, as the TP reduction, the Jc degradation of MgB2 wire is much slower in 30-filament than that in 18-filament at various magnetic fields. At the TP of 5 mm, the Jc degradation comparing with the untwisted wires at 4.2 K and 4 T is up to 30% in 18-filament wire but only about 10% in the 30-filament. This work indicates that the twisting route is very promising to the engineering application of MgB2 superconductor. [ABSTRACT FROM AUTHOR]

Heavy metal pollution in fine particulate matter (PM2.5) is a serious environmental and health concern in China, particularly during winter. Here, we detected 40 elements in 24 h integrated daily PM2.5 samples collected in January 2014 from three typical Chinese metropolises (Beijing, Changchun, and Chengdu) to reflect elemental spatial variations, local sources, and regional transport. The measured elemental concentrations in Changchun were 11.1% and 48.4% higher than those in Beijing and Chengdu, respectively. Thus, PM2.5 from Changchun exhibited high levels and diversity in the elemental profile (characterized by high concentrations of industrial emission elemental markers). The results of elemental ratios and Pb isotopes proved that, except for a coal combustion source, vehicular emissions contributed more to PM2.5 heavy metals in Beijing than in the other two cities; Changchun PM2.5 elements received large contributions from industrial sources, including iron and steel manufacturing, and automobile industry. Moreover, crustal dust from long-range transport of regional air masses from the northwest regions of China played a crucial role in determining elemental levels in Beijing and Changchun, accounting for more than 50% of source intensity. However, a specific dominant source was not determined in Chengdu; the contribution of anthropogenic dust, mainly from construction activities, needs to be paid attention in Chengdu eastern area. This study contributed to enhancing our understanding of elemental spatial distribution characteristics and sources and to setting more judicious standards and strategies for PM2.5 bound heavy metals in China. [ABSTRACT FROM AUTHOR]

Low-cycle fatigue properties and uniaxial ratcheting behavior of a 7050-T6 aluminum alloy were investigated by a non-symmetric cycle stress tests at the normal temperature. The low-cycle fatigue behavior of the alloy was evaluated. The effect of the stress rate, stress amplitudes, and mean stresses on its ratcheting performance was discussed. Considering the ratcheting effect and special working conditions that large mean stresses and small stress amplitudes, based on the same properties under loading, a new fatigue life prediction empirical equation was proposed to estimate the ratcheting life. The results prove that the ratcheting strain of the alloy depends on the stress amplitudes and mean stresses, whereas the stress rate almost has no effect on the ratcheting behavior on account of the rate-independent feature of the material. This equation can give a precise estimate of the ratcheting behavior of large mean stresses and their small amplitudes. [ABSTRACT FROM AUTHOR]

The small intestine is an important digestive organ and plays a vital role in the life of a pig. We tested the hypothesis that the length of the small intestine is related to growth performance and intestinal functions of piglets. A total of 60 piglets (Duroc × Landrace × Yorkshire), weaned at day 21, were fed an identical diet during a 28-day trial. At the end of the study, all piglets were sacrificed, dissected and grouped according to small intestine lengths (SILs), either short small intestine (SSI), middle small intestine (MSI) or long small intestine (LSI), respectively. Positive relationships between SIL and BW, average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratios (G : F) were observed. Final BW, ADG, ADFI and G : F significantly increased (P < 0.05) in MSI and LSI piglets compared with SSI piglets. Short small intestine and MSI had greater jejunal mucosa sucrase and alkaline phosphatase activities (P < 0.05) than LSI piglets. The mRNA level of solute carrier family 2 member 2 (Slc2a2) in the jejunal mucosa of SSI piglets was the greatest. The MSI piglets had a greater (P < 0.05) ileal villus height than other piglets and greater (P < 0.05) villus height-to-crypt depth ratios than LSI piglets. However, the LSI piglets had a greater (P < 0.05) ileal crypt depth than SSI piglets. No significant differences in duodenal, jejunal, caecal and colonic morphologies were detected among the groups. Moreover, luminal acetate, propionate, butyrate and total short-chain fatty acid contents were greater (P < 0.05) in SSI and MSI piglets than those in LSI piglets. In addition, there was greater serum glucose concentration in MSI piglets than other piglets. Serum albumin concentration in SSI piglets was the lowest. In conclusion, these results indicate that SIL was significantly positively associated with growth performance, and in terms of intestinal morphology and mucosal digestive enzyme activity, the piglets with a medium length of small intestine have better digestion and absorption properties. [ABSTRACT FROM AUTHOR]

MgB2 bulks with graphene doping were synthesized by high energy ball milling process. The effect of high energy ball milling and graphene doping on the microstructure and critical current density of MgB2 was studied systematically. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and physical property measurement system (PPMS), respectively. The densities of ball-milled graphene-doped samples were larger than those of pure samples. The superconducting properties of MgB2 could be increased by the high energy ball milling process, in comparison with the sample prepared by grinding process. Moreover, the significant improvement of superconducting properties for ball-milled MgB2 samples could be achieved with the addition of graphene. The combination of graphene doping and suitable ball milling could refine the grain and improve the inter-grain connectivity of MgB2. MgB2 with 3 at% graphene doping prepared by high energy ball milling with 2 h exhibited very high critical current density of 6.4 × 105 A/cm2 at 20 K and 0 T. [ABSTRACT FROM AUTHOR]

To develop the multifunctional photosensitizer NaYb1 –xF4: , the effect of Tm3+ concentration on the photosensitivity in NaYb1 –xF4: nanoparticles (NPs) was investigated. Photosensitivity in NaYb1 –xF4: was characterized by chemical probe method, in which 1,3-diphenylisobenzofuran (DPBF) was used as the indicator; and DPBF consumption rate (k) can be used to evaluate the photosensitivity. Experimental results show that in the concentration range of 0–2% for Tm3+, k decreases linearly with increase in Tm3+ concentration with the slope of 0.3. This is mainly attributed to the introduction of fluorescence channel from Yb3+ to Tm3+, which weakens the energy transfer from Yb3+ to oxygen, decreasing k. The result is also confirmed in theoretical analysis. [ABSTRACT FROM AUTHOR]

A Cu- and Cd-resistant bacterial strain, DC-B3, was isolated from heavy metal-contaminated soils in a Cu mine, was identified as belonging to Pseudomonas sp. and biosorbed Cu2+ and Cd2+ from aqueous solution in the present study. Its biosorption properties as a function of environmental parameters such as contact time, initial concentration, pH, temperature and bacterial dosage were investigated through batch experiments, and the removal capacity peaked at pH 6.0, 40 °C and 0.5 g biomass L−1 at an initial concentration of 105 mg L−1. Sorption occurred extremely rapidly at the beginning, equilibrium was reached after approximately 1 h and 4 h for Cu2+ and Cd2+, respectively, and the biosorption kinetic data for both metals were well fitted by the pseudo-second-order model (r2 > 0.99). Sorption isotherms showed that the adsorptions of both metals were highly favourable, and equilibrium data were better described by the Langmuir model (r2 > 0.98 for Cu2+ and 0.99 for Cd2+), with the estimated maximum sorption capacities of 12.6 and 26.5 mg g−1 for Cu2+ and Cd2+, respectively. Desorption assays suggested that biosorption was a chemical process and that a fraction of the metal ions might have entered the bacterial cells. Fourier transform infrared spectroscopy analysis revealed that hydroxyl, amino, carboxyl and phosphate functional groups on the bacterial cell walls might be mainly responsible for the biosorption, although their contributions to the binding of Cu2+ and Cd2+ were different. This result implied that the strain DC-B3 can be used as a potentially eco-friendly and efficient biosorbent for the remediation of Cu(II) and Cd(II) contaminants. [ABSTRACT FROM AUTHOR]

Ex situ MgB2 is usually considered as with lower critical current density (Jc) compared to the in situ one due to much worse inter-granular connectivity. In this work, we reported the fabrication of ex situ MgB2 superconducting tape without dopants using Monel as sheath materials and Nb as the barrier, which has an excellent Jc of 705 A/mm2 at 4.2 K under 4 T, almost as same as the in situ MgB2 wires. Massive and high-quality precursor powders with small grain sizes and quite low oxygen content were sintered at relatively low temperature and short time, 580 ∘C for 3 h. The effects of heat-treatment conditions and tape thickness on the microstructure and Jc of ex situ MgB2 tapes were discussed. The results suggested that the improvement of grains-connectivity was responsible to the excellent Jc properties of ex situ MgB2 tape. [ABSTRACT FROM AUTHOR]

A series of quasi-static and dynamic tests on bamboo-based honeycomb and bamboo-reinforced foam structures were carried out to investigate their energy absorbing characteristics and the related failure modes. Here, the tube damage shows the typical buckling (bulging) and top surface splitting failure. The results on the individual tubes show that the energy absorbing capacity increases as the diameter-to-thickness ratio decreases. Simple analytical models were also developed to predict the peak load and the corresponding displacement, with reasonably good correlation to the experimental results, in spite of the inherent variability of the bamboo tubes. It was found that different dynamic responses of the individual bamboo tubes and grouped bamboo tubes in the honeycomb cores affect their energy absorbing capabilities. The composite structure made from bamboo and foam shows that the embedded tube exhibits a higher energy absorption capacity than the sum of the individual foam and bamboo, due to the constraint offered by the foam. [ABSTRACT FROM AUTHOR]

Effect of preliminary torsional strain on low-cycle fatigue of Q345B steel was studied. The specimens were first 0, 180, and 360_ twisted, then the low-cycle fatigue of Q345B steel was evaluated in the strain range of 0.3–0.8% by the method of axisymmetrical strain. The cycling response, cyclic stress–strain relationship, strain–life relationship, fatigue life prediction model, and seismic stability at different torsion angles were obtained and analyzed. The strain–life curve is shown to slope down as a power function. The fatigue life comes down with preliminary torsional strain at a constant level. The cycling response varied from cyclic hardening to cyclic softening in preliminary torsion, and the cyclic hardening rate increased linearly with the strain amplitude. The parameters of the Coffin–Manson relation are corroborated with experimental data. After heat treatment, the seismic stability of the material is improved, with torsional strain greatly reducing this characteristic. Electron microscope examination of fatigue fracture revealed a fatigue crack initiating on the surface of the specimen. The propagating crack deviated from its direction, and plasticity of the material dropped as a result of preliminary torsional strain. [ABSTRACT FROM AUTHOR]

PtCu-embedded graphene (PtCu/graphene) is one of the high-efficiency catalysts in catalytic oxidation of CO. In this paper, CO catalytic oxidation on PtCu/graphene is studied by density functional theory. According to the calculation, the coadsorption configuration is more stable than the configuration of O2 or CO adsorption on PtCu/graphene. Thus, the reaction mechanism of catalytic CO oxidation is the LH mechanism, which proceeds via two steps with barrier energies of 0.21 eV and 0.52 eV, respectively. Compared with pure Pt/graphene and Cu/graphene, Pt mixed in Cu can lower the barrier energy, improving the catalytic activity. Therefore, the research of PtCu/graphene can provide a certain reference value and guidance for the study of another similar catalytic CO oxidation. [ABSTRACT FROM AUTHOR]

Contents : The aim of this study was to determine how the duration of culture affects the ubiquitination of zona pellucida (ZP) proteins (ZP1, ZP2 and ZP3) during porcine oocyte maturation in vitro. We analysed the changes in ZP protein ubiquitination under three conditions: (i) during oocyte maturation from stage GV to MII; (ii) in oocytes cultured for different periods of time; and (iii) in oocytes treated with an antibody against PSMD4. Our results show that ZP1 and ZP2 are ubiquitinated at the GV stage, while ZP1, ZP2 and ZP3 are ubiquitinated at the MII stage, and band intensities for these proteins were significantly different between the GV and MII stages (p < .05). We also found that ubiquitination occurs in ZP1, ZP2 and ZP3 after cultured for 46, 52, 58 and 64 hr, and that the level of ubiquitinated ZP1 was significantly different in oocytes that were cultured for different time periods. Finally, treatment with an antibody against PSMD4 resulted in a significant decrease in ZP1 ubiquitination (p < .05), without affecting ZP2 or ZP3. The number of attached sperms per oocyte was also significantly different between control and anti‐PSMD4‐treated groups. Thus, we concluded that ZP1 and ZP2 are ubiquitinated at the GV stage, and ZP1, ZP2 and ZP3 are ubiquitinated at the MII stage. As the duration of culture increases, the ubiquitination levels of ZP proteins decrease. We also found that PSMD4 improves ZP1 ubiquitination during in vitro culture of porcine oocytes and effectively inhibits sperm–oocyte binding. [ABSTRACT FROM AUTHOR]

The effect of graphene (G) coated Si, Ti and Nb additions on the superconducting properties of MgB2 was systematically studied. The additives were prepared by a coating process and all introduced powders were scattered and combined with graphene. The coating process was useful for the uniform distribution of additives in MgB2 samples. The additives could effectively make the refinement of MgB2 grain size, which achieved an enhancement of surface pinning. Meanwhile, the densities of all the doped samples were larger than those of pure samples, which ensured a better intergrain connection for supercurrent. Therefore, the critical current density of MgB2 with 8 wt% G coated Nb addition got a significant enhancement due to the improvement of grain connectivity and flux pinning properties. [ABSTRACT FROM AUTHOR]

The effects of microstructure and stress ratio on high cycle fatigue of nickel superalloy Nimonic 80A were investigated. The stress ratios of 0.1, 0.5 and 0.8 were chosen to perform fatigue tests in a frequency of 110 Hz. Cleavage failure was observed, and three competing failure crack initiation modes were discovered by a scanning electron microscope, which were classified as surface without facets, surface with facets and subsurface with facets. With increasing the stress ratio from 0.1 to 0.8, the occurrence probability of surface and subsurface with facets also increased and reached the maximum value at R = 0.5, meanwhile the probability of surface initiation without facets decreased. The effect of microstructure on the fatigue fracture behavior at different stress ratios was also observed and discussed. Based on the Goodman diagram, it was concluded that the fatigue strength of 50% probability of failure at R = 0.1, 0.5 and 0.8 is lower than the modified Goodman line. [ABSTRACT FROM AUTHOR]

Abstract: The effects of ultrasonic nanocrystal surface modification (UNSM) on residual stresses and fatigue crack initiation were investigated in various engineering alloys. It was found that higher contact force and smaller pin in UNSM produced higher compressive residual stresses at the surface and subsurface of the alloys. The compressive residual stresses were found to be higher in high yield strength alloys. A deeper compressive residual stress field was observed in alloys with higher elastic modulus and strain hardening exponent. Fatigue crack initiation was found to occur subsurface in the material where the effect of UNSM hardening was saturated. It was concluded that deeper UNSM hardening produces higher fatigue life. [ABSTRACT FROM AUTHOR]

The chain drive system is the most important subsystem in a mining scraper conveyor. Compared with the general chain drive system, that in a scraper conveyor is highly coupled. The rings on a chain come in contact not only with the sprocket wheels but also with the central chutes and scrapers. In order to improve the reliability of the scraper conveyor, a contact analysis of the chain drive system based on its meshing properties was performed. Vogit model-based translational and rotating models of the chain drive system were first introduced. A finite element model of the chain drive system was then established. Contact simulations were conducted using the software LS-DYNA. Von Mises stress and contact pressure curves on various dangerous areas of the horizontal ring, vertical ring, and sprocket wheel were obtained. The von Mises stress and the contact pressure of the rings and the sprocket wheel were compared, and their differences were analysed. Results indicate that the maximum contact pressure for the horizontal and vertical rings is considerably larger than the maximum von Mises stress. The maximum contact pressure for the horizontal ring exceeds 2000 MPa, which is 90 % larger than the von Mises stress (1100 MPa). Meanwhile, the contact pressure for the sprocket wheel is considerably less than the von Mises stress. Therefore, the failure mode of the rings and the sprocket wheels differs. Contact analysis based on meshing properties is useful in describing the dynamic properties of the chain drive system in detail. This study provides guidance for overcoming chain break and jam problems in scraper conveyors. [ABSTRACT FROM AUTHOR]

For most bacterial lung infections, the concentration of unbound antimicrobial agent in lung interstitial fluid has been thought to be responsible for antimicrobial efficacy. In this study, a diffusion-limited physiologically based pharmacokinetic ( PBPK) model was developed to predict the pulmonary pharmacokinetics of florfenicol ( FF) in pigs. The model included separate compartments corresponding to blood, diffusion-limited lung, flow-limited muscle, liver, and kidney and an extra compartment representing the remaining carcass. The absorption rate constant and renal and hepatic clearance of FF were determined in vivo. Other parameters were taken from the literature or optimized based on existing pharmacokinetic data. All mathematical operations during the development of the model were performed using acslXtreme version 3.0.2.1 (Aegis Technologies Group, Inc., Huntsville, AL, USA). The model accurately predicted the concentration-time courses of FF in lung interstitial fluid, serum, and plasma following different dosing schedules, except at the dose of 15 mg/kg. When compared with the tissue residue data, the model generally underestimated the FF concentration at the injection site, whereas it gave good predictions of FF concentrations in lung, liver, and kidney at early time points. The model predictions provide a scientific basis for the dosage regimen design of FF. [ABSTRACT FROM AUTHOR]

For most bacterial lung infections, the concentration of unbound antimicrobial agent in lung interstitial fluid has been considered as the gold standard for estimating the antibacterial efficacy. In this study, the pharmacokinetics of florfenicol ( FF) in porcine lung interstitial fluid was investigated after single intramuscular administration at two different doses (20 and 50 mg/kg). Twelve pigs underwent thoracotomy under general anesthesia. Then, the CMA/30 probe was implanted into the lung and perfused at 1 μL/min. The microdialysis ( MD) samples were collected on a preset schedule and analyzed by high-performance liquid chromatography ( HPLC). Noncompartmental pharmacokinetic analysis was performed. FF exhibited rapid distribution and slow elimination in porcine lung interstitial fluid. The main pharmacokinetic parameters at 20 and 50 mg/kg were 4.88 ± 0.54 and 10.36 ± 2.52 μg/ mL for the maximum concentration (Cmax), 3.25 ± 0.32 and 3.50 ± 0.27 h for the time to Cmax (Tmax), 9.47 ± 6.84 and 7.75 ± 3.23 h for the half-life (t1/2), 0.10 ± 0.06 and 0.10 ± 0.04 1/h for the terminal elimination rate constant ( λz), 13.85 ± 7.97 and 11.42 ± 2.79 h for the mean residence time ( MRT), 37.77 ± 8.13 and 71.15 ± 16.99 h·μg/ mL for the area under the curve from time 0 to 18.25 h ( AUC0-18.25), and 51.18 ± 20.11 and 88.78 ± 27.58 h·μg/ mL for the area under the curve from time 0 to infinity ( AUC0-∞), respectively. [ABSTRACT FROM AUTHOR]

For armoured face conveyors (AFC) in coal mines, fracture and jam phenomena of the chain are common failure patterns in the chain assembly. These failure patterns are caused by chain's severe vibrations from uneven loads on the conveyor. However, due to limitations of harsh operating environment in coal mines, performing underground experiments is difficult to obtain real vibration signals. Multi-body dynamic simulation is an efficient approach to analyse the complex dynamic behaviour of chain assembly in the AFC. In order to determine the actual dynamic properties of chain assembly in the AFC under different operating conditions, multi-body simulation was used to analyse the vibration properties of the chain assembly. In this study, theoretical analysis of contact force between horizontal and vertical rings, and between sprocket wheel and rings in the chain assembly was initially performed. Rigid and rigid-flexible coupling models of the chain assembly were then established. Dynamic simulations through two types of models, that is, rigid and rigid-flexible coupling models were conducted under full-, half- and empty load conditions using the ADAMS software. Trends of contact force, stress, and velocity of horizontal and vertical rings under various working conditions were obtained, and vibration properties of the chain assembly were analysed based on the corresponding curves. Results indicate that the maximum velocity is 1.75 m/s in the rigid simulation, whereas the maximum velocity is 3.0 m/s in the rigid-flexible coupling simulation. The rigid-flexible coupling method is proven to be more accurate and feasible in describing the dynamic properties of the chain assembly than the rigid method. The proposed method should be preferentially utilized in performing multi-body dynamic simulation of the chain assembly in the AFC. This study provides references for the structural optimization and design of the chain assembly in mining AFC. [ABSTRACT FROM AUTHOR]

Ratcheting occurs easily because of the presence of mean stress during the stress-control fatigue of engineering components. For ductility exhaustion dominated fatigue failure, a new fatigue life prediction model is developed by introducing the mean ratcheting strain rate to incorporate the effects of ratcheting and mean stress on fatigue life. The prediction accuracy of the proposed model was compared with that of the generalised damage parameter, Xia-Kujawski-Ellyin, Walker and Goswami models. Specifically, the model predictions and tested lives were compared using nine sets of experimental data from the literature. In the statistical analysis of these five models, the proposed model provides the highest accuracy and robust life predictions with the lowest model prediction errors. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the effect of source (corn DDGS, rice bran, or soybean) or form of oil (extracted or intact) on apparent total tract digestibility (ATTD) and true total tract digestibility (TTTD) of acid-hydrolyzed ether extract (AEE) and fatty acids. The study determined and compared the ATTD or TTTD of AEE and fatty acids in extracted corn oil, rice oil, and soybean oil with intact oil in corn DDGS, full-fat rice bran, and full-fat soybean. Seventy-eight barrows (initial BW = 47.2 ± 3.9 kg; Duroc x Landrace x Yorkshire) were allotted to 1 of 13 dietary treatments in a randomized complete block design with 6 barrows in each dietary treatment. The 13 experimental diets included 1 cornstarch-soybean meal basal diet (AEE, 0.56%) and 3 diets containing 6% extracted oils (corn oil, rice oil, and soybean oil) and 9 diets supplemented with 3 levels of corn DDGS (17%, 34%, and 51%), full-fat rice bran (14%, 28%, and 42%), and full-fat soybean (12%, 24%, and 36%). These diets provided about 2%, 4%, and 6% intact oil, respectively. The barrows were housed in individual metabolism crates and were fed the assigned test diets at 4% of initial BW per day. A 5-d total collection of feces followed a 7-d diet adaptation period. The ATTD of AEE were calculated for each diet. The endogenous flow of AEE associated with each ingredient and values for TTTD were calculated using regression methods. The ATTD of AEE were greater (P < 0.05) for extracted oil than for intact oil. Compared to extracted oil, intact oil had lower (P < 0.01) ATTD of palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:3). However, a source by form interaction (P < 0.01) was observed for ATTD of C18:0, C18:2, and C18:3. The ATTD of C18:0, C18:2, and C18:3 in extracted corn and rice oil were greater compared with intact corn DDGS and rice oil (P < 0.05), while there was no significant difference for the ATTD of C18:0, C18:2, and C18:3 between extracted soybean oil and intact oil in full-fat soybean. In conclusion, lipids that are extracted have a greater digestibility compared with intact lipids, and this is especially true regarding saturated fatty acids. The ATTD of AEE in 2 forms of rice oil (intact oil and extracted oil) was less than the values in corn oil and soybean oil. The TTTD of AEE in corn DDGS and full-fat soybeans were greater than in full-fat rice bran. [ABSTRACT FROM AUTHOR]

Montmorillonite (MMT) is widely used as a mycotoxin adsorbent in animal feeds, but its safety remains unclear. This study was conducted to investigate the safety of MMT supplementation in diets fed to starter pigs. A total of 120 32-d-old piglets (initial weight, 8.0 ± 0.9 kg) were randomly allotted into dietary treatments with graded MMT levels (0 [FS 0], 0.5% [FS 0.5], 1.0% [FS 1.0], 2.5% [FS 2.5], and 5.0% [FS 5.0]) with 6 replicate pens per treatment and 4 pigs per pen. All diets were fed for 28 d. As the MMT level increased, ADG and G:F changed in a linear and quadratic manner, while ADFI was linearly decreased (P > 0.05). Compared with FS 0, ADG, ADFI, and G:F of pigs in FS 1.0 increased (P < 0.05). However, the ADFI in pigs of FS 5.0 was lower than that in pigs of FS 0 (P < 0.05). The relative liver weight activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) changed in a linear and quadratic manner (P < 0.05). Compared with FS 0, pigs in FS 2.5 and FS 5.0 had a greater serum ALT (P < 0.05), while AST activity significantly increased in pigs of FS 5.0 (P < 0.05). Dietary MMT supplementation decreased serum Mg content in a linear and quadratic manner (P < 0.05), while Zn and Cu contents were linearly decreased (P < 0.05). Serum Zn and Cu contents of pigs in FS 0.5, FS 2.5, and FS 5.0 groups were lower than those in the control. Pigs fed with 2.5% and 5% MMT showed hepatic histopathological changes, including swelling, granular and vesicular degeneration, and apparent vacuolar degeneration. In addition, the content of serum total antioxidant capacity (T-AOC) and activity of glutathione peroxidase (GSH-PX) decreased in a linear and quadratic manner (P < 0.05). Compared to the control, 5.0% MMT significantly increased piglets' serum malondialdehyde (MDA) concentration and decreased GSH-PX activity (P < 0.05). T-AOC concentration in the pigs fed 2.5% and 5.0% MMT was lower than that in the control group (P < 0.05). Serum superoxide dismutase (SOD) activity changed in a quadratic manner (P < 0.05). Piglets in FS 1.0 showed a higher SOD activity when compared with the control (P < 0.05). These results indicate that supplementation of MMT higher than 1.0% can negatively affect liver structure and serum mineral content, and 5.0% MMT supplementation would also decrease feed intake, aggravate liver damage, and reduce the antioxidant capacity of starter pigs. Therefore, excess supplementation of MMT is not safe in starter pigs. [ABSTRACT FROM AUTHOR]

Time-dependent creep behavior of rocks is crucial not only for assessing geophysical hazards, such as earthquake rupture and volcanic eruption, but also for analyzing the long-term stability of rock engineering structures, such as underground mines and underground excavations. In the present paper, multiple stress-stepping creep tests on green sandstone under uniaxial stress conditions were performed. Results from stress-stepping creep experiments show that creep strain rates are highly dependent on the level of applied stress. Then, a time-dependent creep model based on damage constitutive law at a mesoscale was proposed to model the time-dependent behavior of heterogeneous brittle rocks. In the proposed model, the rock heterogeneity is considered by assuming the rock parameters following a statistical Weibull distribution, and both the maximum tensile strain criterion and the Mohr-Coulomb criterion are used as two damage thresholds to control the rock damage. The damage-based creep model is implemented by programming on the basis of finite-element software. Then the model was validated by comparing the numerical simulations with the experimental results. The model accurately captures the time-dependent creep behavior observed in the laboratory. It was then used to simulate the time-dependent evolution of damaged zone around an opening under different lateral pressure coefficients. The distribution of damage around the opening is realistically reproduced, and the simulations indicated that the spatial distribution of damage zones, as well as time to failure, is closely related to the lateral pressure coefficient. [ABSTRACT FROM AUTHOR]

Effects of ultrasonic nanocrystal surface modification (UNSM) on the very high cycle fatigue response of AISI 310 stainless steel have been investigated. The higher impact force used in UNSM treatment showed a higher fatigue life improvement. The fatigue life improvement was higher in crack initiation from the surface of specimens. The subsurface crack initiation depth in the alloy increased with increase in the fatigue failure cycles. It was concluded that UNSM treatment can increase the life of the alloy significantly up to very high cycle fatigue. [ABSTRACT FROM AUTHOR]

Black carbon (BC) aerosol at high altitudes of the Qinghai-Tibetan Plateau has potential effects on the regional climate and hydrological cycle. An intensive measurement campaign was conducted at Qinghai Lake (~3200m above sea level) at the edge of the northeastern Qinghai- Tibetan Plateau during winter using a ground-based single particle soot photometer (SP2) and a photoacoustic extinctiometer (PAX). The average concentration of refractory BC (rBC) and number fraction of coated rBC were found to be 160±190 ngm-3 and 59% for the entire campaign, respectively. Significant enhancements of rBC loadings and number fraction of coated rBC were observed during a pollution episode, with an average value of 390 ngm-3 and 65%, respectively. The mass size distribution of rBC particles showed log-normal distribution, with a peak diameter of ~187 nm regardless of the pollution level. Five-day backward trajectory analysis suggests that the air masses from north India contributed to the increased rBC loadings during the campaign. The potential source contribution function (PSCF) model combined with the fire counts map further proves that biomass burning from north India is an important potential source influencing the northeastern Qinghai-Tibetan Plateau during the pollution episode. The rBC mass absorption cross section (MACrBC/ at λ = 532 nm was slightly larger in clean days (14.9m² g-1) than during the pollution episode (9.3m² g-1), likely due to the effects of brown carbon and the uncertainty of the MACrBC calculation. The MACrBC was positively correlated with number fraction of coated rBC during the pollution episode with an increasing rate of 0.18 (m² g-1)%-1. The number fraction of coated rBC particles showed positive correlation with light absorption, suggesting that the increase of coated rBC particles will enhance the light absorption. Compared to rBC mass concentration, rBC mixing sate is more important in determining absorption during the pollution episode, estimated from the same percentage-wise increment of either rBC mass concentration or the number fraction of coated rBC. The estimated BC direct radiative forcing was C0.93Wm-2 for the pollution episode, which is 2 times larger than that in clean days. Our study provides insight into the potential climatic impacts of rBC aerosol transported to the Qinghai-Tibetan Plateau from south Asian regions, and is also useful for future modeling studies. [ABSTRACT FROM AUTHOR]

During winter 2013-2014 aerosol mass spectrometer (AMS) measurements were conducted for the first time with a novel PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 µm) lens in two major cities of China: Xi'an and Beijing. We denote the periods with visibility below 2 km as extreme haze and refer to the rest as reference periods. During the measurements in Xi'an an extreme haze covered the city for about a week and the total non-refractory (NR)-PM2.5 mass fraction reached peak concentrations of over 1000 µg m-3. During the measurements in Beijing two extreme haze events occurred, but the temporal extent and the total concentrations reached during these events were lower than in Xi'an. Average PM2.5 concentrations of 537 ± 146 µg m-3 and 243 ± 47 µg m-3 (including NR species and equivalent black carbon, eBC) were recorded during the extreme haze events in Xi'an and Beijing, respectively. During the reference periods the measured average concentrations were 140 ± 99 µg m-3 in Xi'an and 75 ± 61 µg m-3 in Beijing. The relative composition of the NR-PM2.5 evolved substantially during the extreme haze periods, with increased contributions of the inorganic components (mostly sulfate and nitrate). Our results suggest that the high relative humidity present during the extreme haze events had a strong effect on the increase of sulfate mass (via aqueous phase oxidation of sulfur dioxide). Another relevant characteristic of the extreme haze is the size of the measured particles. During the extreme haze events, the AMS showed much larger particles, with a volume weighted mode at about 800 to 1000 nm, in contrast to about 400 nm during reference periods. These large particle sizes made the use of the PM2.5 inlet crucial, especially during the severe haze events, where 39 ± 5 % of the mass would have been lost in the conventional PM1 (particulate matter with aerodynamic diameter ≤ 1 µm) inlet. A novel positive matrix factorization procedure was developed to apportion the sources of organic aerosols (OA) based on their mass spectra using the multilinear engine (ME-2) controlled via the source finder (SoFi). The procedure allows an effective exploration of the solution space, a more objective selection of the best solution and an estimation of the rotational uncertainties. Our results clearly show an increase of the oxygenated organic aerosol (OOA) mass during extreme haze events. The contribution of OOA to the total OA increased from the reference to the extreme haze periods from 16.2 ± 1.1 to 31.3 ± 1.5 % in Xi'an and from 15.7 ± 0.7 to 25.0 ± 1.2 % in Beijing. By contrast, during the reference periods the total OA mass was dominated by domestic emissions of primary aerosols from biomass burning in Xi'an (42.2 ± 1.5 % of OA) and coal combustion in Beijing (55.2 ± 1.6 % of OA). These two sources are also mostly responsible for extremely high polycyclic aromatic hydrocarbon (PAH) concentrations measured with the AMS (campaign average of 2.1 ± 2.0 µg m-3 and frequent peak concentrations above 10 µg m-3). To the best of our knowledge, this is the first dataset where the simultaneous extraction of these two primary sources could be achieved by conducting on-line AMS measurements at two areas with contrasted emission patterns. [ABSTRACT FROM AUTHOR]

Titanium alloy is widely used in aeronautics engineering applications and undertakes high-frequency fatigue load. Tests are performed to investigate the very high cycle fatigue (VHCF) behaviour of TC17 alloy through ultrasonic fatigue machine at R = 0.1. Thermal dissipation of VHCF for the alloy in 20 kHz frequency is also studied, and a model is proposed to describe the temperature increment of VHCF in the framework of thermodynamics by estimation of the inelastic thermal dissipation at active sites. Failure probability prediction method is used to evaluate the VHCF dispersion based on the multi-scale method and fatigue thermal dissipation analysis. [ABSTRACT FROM AUTHOR]

Black carbon (BC) aerosol at high-altitude Qinghai-Tibetan Plateau has potential effects on the regional climate and hydrological cycle. An intensive measurement campaign was conducted at Qinghai Lake (~ 3200 a.s.l.) at the edge of the northeastern Qinghai-Tibetan Plateau during winter using a ground-based single particle soot photometer (SP2) and a photoacoustic extinctiometer (PAX). The average BC concentration and number fraction of coated BC were found to be 160±190 ng m-3 and 59.3% for the entire campaign, respectively. Significant enhancements of BC loadings and number fraction of coated BC were observed during pollution episode, with an average value of 390 ng m-3 and 64.6%, respectively. The mass size distribution of BC particles showed lognormal distribution with a peak diameter of ~ 187 nm regardless of the pollution level. Five-day backward trajectory analysis combined with the fire counts map suggests that the biomass burning air masses from North India contributing to the increased BC loadings during the campaign. The potential source contribution function (PSCF) model further proves that North India is an important potential region influencing northeastern Qinghai-Tibetan Plateau during the pollution episode. The BC mass absorption cross section (MACBC) at λ= 532 nm was slightly larger during pollution episode (10.2 m² g-1) than in clean days (8.9 m² g g-1), likely due to the higher mixing state of BC with other chemical components during pollution episode. The number fraction of coated BC particles showed positive correlation with light absorption, suggesting that the increase of coated BC particles will enhance the light absorption. The estimated BC direct radiative forcing was + 0.93W m² for pollution episode, which is 2 times larger than that in clean days. Our study provides insight into the potential climatic impacts of BC aerosol transported to the Qinghai-Tibetan Plateau from South Asian regions, and is also useful for future modeling studies. [ABSTRACT FROM AUTHOR]

Black carbon (BC) aerosol at high-altitude Qinghai-Tibetan Plateau has potential effects on the regional climate and hydrological cycle. An intensive measurement campaign was conducted at Qinghai Lake (~ 3200 a.s.l.) at the edge of the northeastern Qinghai-Tibetan Plateau during winter using a ground-based single particle soot photometer (SP2) and a photoacoustic extinctiometer (PAX). The average BC concentration and number fraction of coated BC were found to be 160 ± 190 ngm-3 and 59.3% for the entire campaign, respectively. Significant enhancements of BC loadings and number fraction of coated BC were observed during pollution episode, with an average value of 390 ngm-3 and 64.6 %, respectively. The mass size distribution of BC particles showed lognormal distribution with a peak diameter of ~ 187nm regardless of the pollution level. Five-day backward trajectory analysis combined with the fire counts map suggests that the biomass burning air masses from North India contributing to the increased BC loadings during the campaign. The potential source contribution function (PSCF) model further proves that North India is an important potential region influencing northeastern Qinghai-Tibetan Plateau during the pollution episode. The BC mass absorption cross section (MACBC) at λ = 532nm was slightly larger during pollution episode (10.2m² g-1) than in clean days (8.9m² g-1), likely due to the higher mixing state of BC with other chemical components during pollution episode. The number fraction of coated BC particles showed positive correlation with light absorption, suggesting that the increase of coated BC particles will enhance the light absorption. The estimated BC direct radiative forcing was + 0.93Wm-2 for pollution episode, which is 2 times larger than that in clean days. Our study provides insight into the potential climatic impacts of BC aerosol transported to the Qinghai-Tibetan Plateau from South Asian regions, and is also useful for future modeling studies. [ABSTRACT FROM AUTHOR]

This paper presents an experimental research on timber columns with externally bonded fibre reinforced polymer sheets, which consist of aramid fibre reinforced polymer, carbon fibre reinforced polymer and basalt fibre reinforced polymer. This is to provide a strengthening solution to upgrade the structural behaviour and load carrying capacities of such columns under the influence of fractured wood texture. In total, 14 columns were constructed and tested, consisting of 8 circular timber columns and 6 square ones. Besides, three columns of such two section types with knag were reinforced by wrapping of carbon fibre reinforced polymer sheets and tested. The failure mode was analysed, as well as the fracture surface. Externally bonded fibre reinforced polymer sheets were found to be very effective in upgrading the compressive strength of the columns strengthened. The enhancement on load carrying capacities by fibre reinforced polymer reinforcement is in the range of 69-103% for the specimens with a circular section and of 35-83% for the ones with a square section. The test results also show that better ductile behaviour and higher ultimate load carrying capacities were obtained for the columns with externally reinforcing of fibre reinforced polymer sheets. However, there is a great reduction in ultimate loading capacities on columns with fractured wood texture, and the cracks were found on the fracture surface because of the fibres near the cracks being compressed. [ABSTRACT FROM AUTHOR]

Low cycle fatigue behaviour of Q345B steel and its smooth welded joint were experimentally investigated in fully reversed strain-control at constant strain rate of 0·005 s−1. The cyclic stress response characteristics, strain-life and strain-energy relationships were obtained and analysed in the strain regime 0·3-0·7%. It was found that Q345B showed significant cyclic hardening and softening above and below the 0·4% strain amplitudes, respectively. The welded joints showed cyclic hardening in the entire strain regime because of the mechanical inhomogeneity. The low cycle transition life, fatigue strength and fatigue life of welded joint were found significantly lower with increase in the cyclic hardening. The experimental data were used to extract the Coffin-Manson parameters and the strain-life relationship. In addition, the expressions of plastic strain energy and fatigue life were also obtained using the energy prediction method. [ABSTRACT FROM AUTHOR]

Based on the experimental tests of timber square columns strengthened by fibre-reinforced polymer sheets under axial compression, the failure modes, load carrying capacity, loading-strain curves, ductile and stiffness factors were examined. The results showed that in comparison with specimens without FRP reinforcement, the axial load carrying capacity, the peak of compression strain and stiffness of specimens with fibre-reinforced polymer reinforcement were all improved. The ultimate load carrying capacity of specimens with fibre-reinforced polymer reinforcement was improved by 68·9-100·2%. However, the ultimate displacement was decreased by 46·1-56·9%, and the lowest displacement was found in the specimens strengthened by two layers of basalt fibre-reinforced polymer. Meanwhile, specimens reinforced by two layer of carbon fibre-reinforced polymer and aramid fibre-reinforced polymer sheets showed a higher level of ultimate displacement and stiffness than specimens with basalt fibre-reinforced polymer reinforcement. Additionally, the failure mode of tested specimens was influenced not only by the type of fibre-reinforced polymer sheets but also by the fractured wood texture. [ABSTRACT FROM AUTHOR]

Fibroblastic rheumatism ( FR) is a rare condition characterized by symmetrical polyarthritis and multiple cutaneous nodules. Approximately 30 cases have been reported worldwide to date. Laboratory tests are not particular useful to confirm the disease. Diagnosis is mainly dependent on the characteristic histopathological features: thickened collagen fibres with spindle-shaped cell proliferation in the skin lesion. We report a case of a 48-year-old Chinese man with typical clinical features of FR. In addition to the characteristic histopathological findings, multinuclear giant cell infiltration in skin lesions was detected, in this case. The evaluation of microelements revealed a raised blood lead level) of 129 μg/L (normal range 0-99 μg/L) These two features have never been described in the previous medical literature on FR. Thus, we propose that examining the infiltrated cells in detail in histopathological studies and inspecting the levels of lead and other microelements in the blood may increase our understanding of the pathogenesis of FR. [ABSTRACT FROM AUTHOR]

ABSTRACT Fatigue behaviour of AISI 310 stainless steel has been investigated up to very high cycles. The fatigue crack initiation sites were found at the surface of the material. Persistent slip bands developed at the surface of the specimens led to the crack initiation. At lower stress levels, shallow persistent slip bands were found at the surface of the specimens, and the fatigue limit was obtained. Notched specimens showed lower fatigue lives. Notched specimens with higher stress concentration factor ( Kt) showed higher fatigue strength reduction factor ( Kf). It was found that shallow notches of depth ~100 µm may reduce the fatigue life substantially. [ABSTRACT FROM AUTHOR]

In this study, we aimed to characterize the mechanical response of polytetrafluoroethylene (PTFE) laminates under a tension-tension load-control fatigue test (frequency = 5 Hz, load ratio = 0) and provided an analysis of the failure patterns of the PTFE material with consideration of crystalline phase transformation. In the final results, the evolution of the cyclic creep strain and stress-number of cycles to failure (S-N) curves presented duplex properties accompanying the fatigue life increasing to high cycles (cycle fatigue > 105). A simple phenomenological damage index was defined in this study to describe the cyclic creep process. Additionally, the scanning electronic machine investigation suggested that local fibrosis caused by crystalline phase transformation to phase I led to the initiation of fatigue crack, and the fiber formation and orientation was found to be beneficial to a higher tensile strength and better resistance to crack propagation. The aspect of cyclic-load-induced crystallization was observed by the microfocus hard X-ray diffraction beamline from a new insight. The crystalline phase transformation led to a gradient distribution of crystallinity and lateral crystallite size along the crack propagation direction. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41113. [ABSTRACT FROM AUTHOR]