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Purpose: The anticorrosion coatings used in marine and atmospheric environment are subjected to many environmental factors. And the aging failure has been puzzling researchers. The purpose of this study is to find the correlation between the initial aging of epoxy coatings and the typical marine atmospheric environmental factors. Design/methodology/approach: The epoxy coatings were subjected to a one-year exposure in three typical marine atmospheres. Meanwhile, principal component analysis, linear regression and Spearman and gray correlation analysis were applied to quantify the environmental characteristics and establish correlations with the coating aging. Findings: The results indicate that the coating will undergo macroscopic fading and chalking upon exposure to the marine atmosphere, while microscopic examination reveals holes, cracks and partial peeling. The adhesion performance and electrochemical properties of the coating deteriorated with prolonged exposure, coating aging mainly occurs with the generation of O-H bonds and the breakage of molecular chains such as C-N and C-O-C. The coating was most deeply aged after exposure to the Xisha, followed by Zhoushan and finally Qingdao. Environmental factors affect the photooxidative aging and hydrolytic degradation processes of coatings and thus coating aging. To further demonstrate the correlation between environmental factors and coating aging, principal component analysis was used. The correlation model between environmental factors and coating aging was subsequently obtained. The correlation model between the rate of coating adhesion loss (E) and the comprehensive evaluation parameter of environmental factors (Z) is expressed as E = 0.142 + 0.028Z. Meanwhile, the Spearman correlation analysis and gray correlation method were used to investigate the impact of each environmental factor on coating aging. Solar irradiation, relative humidity and wetting time have the highest correlation with coating aging, which are all above 0.8 and have the greatest influence on coating aging; wind speed and temperature have the smallest correlation with coating aging, which are about 0.6 and have the least influence on coating aging. Originality/value: This paper establishes a correlation between typical marine environmental factors and coating aging performance, which is crucial for predicting the service life of other coatings in diverse environments. [ABSTRACT FROM AUTHOR]

This study proposes random-parameters multinomial logit models, with heterogeneity in means and variances, to explore the differences in the factors influencing injury severities of drivers involved in different types of two-vehicle crashes. The models are verified using crash data from the United Kingdom (UK) over three years (2016–2018). Three types of crashes are separately identified (car-car, car-truck, and truck-truck crashes). In this study, a wide variety of potential variables, including the driver, vehicle, road, and environmental characteristics, are considered, with two possible injury-severity outcomes: severe and slight injury. The results show that unobserved heterogeneity existed for young drivers in both car-car and truck-truck crash models and the 30 mph speed limit in the three separate models. Remarkably variations are observed in crashes involving different types of vehicles. The driver's age and gender, speeding, sideswipes, presence of junctions, weekdays, unlit, and weather conditions significantly impact driver-injury severities in various types of vehicle crashes. These findings are expected to help policymakers seek to improve highway safety and implement proper safety countermeasures. [ABSTRACT FROM AUTHOR]

In order to achieve the goal of carbon peaking and carbon neutralization, we must vigorously develop renewable energy. As one of the important renewable energy sources, the development and utilization of biomass energy has a high cost, and it is difficult to compete with traditional fossil energy in the early stage of development. Therefore, it is necessary for the government to escort the development of the biomass energy industry through legal means. First of all, on the basis of fully analyzing the development prospects of China's biomass energy, the article sorts out the laws and regulations related to biomass energy in China, and finds the shortcomings. Secondly, this paper draws on the institutional experience of the United States, Brazil, Sweden and other countries with relatively developed biomass energy industry, and provides suggestions for improvement from three aspects: law, policy and administrative system, with a view to supporting China's development of biomass energy industry and realizing the "dual carbon target" theoretically. [ABSTRACT FROM AUTHOR]

Based on energy balance theory, using Theil–Sen median trend analysis and the Mann–Kendall test, this research studied the applicability of the complementary theory of evapotranspiration (ET) over Ningxia in the Upper Reaches of the Yellow River with MOD16 ET product and the measured data of meteorological stations, based on which ET drought index (EDI) was proposed for the first time. Moreover, the usability of EDI was also verified and its influencing factors were analyzed. The results revealed that there was a complementary relationship between AET and PET in 91.1% of the area in Ningxia, including strictly complementary and asymmetrically complementary relationships in 69.2% and 21.9% of the total area, respectively. EDI ranged from 0 to 1 and was useful to accurately reflect the degree of drought of the study area on the annual and monthly scales. From 2001 to 2020, the average annual EDI was 0.66, and the smallest monthly EDI was in January and the largest was in May. EDI of different time scales had different influencing factors. Precipitation was the most influencing factor of annual EDI, but the influencing factors of monthly EDI was different over time. However, surface non-precipitation water replenishment, such as irrigation, had great impact both on annual EDI and monthly EDI. The application scope of the theory of ET complementarity was extended to the study area for the first time, and EDI was proposed and applied, which will provide a theoretical basis and empirical reference for drought research based on ET data in arid and semi-arid areas. [ABSTRACT FROM AUTHOR]

In the context of the 'carbon peaking and carbon neutrality goals', renewable energy, with its clean and low-carbon characteristics, has become one of the key driving forces for sustainable development in China. However, the inherent disadvantages of the renewable energy industry, such as high initial investment costs, technical difficulties, and slow returns on investment, make it difficult to compete with traditional fossil energy sources in the market economy at the initial stage of its establishment. Therefore, after considering the environmental and ecological value, economic value, and industrial growth dilemma brought by the development of renewable energy industry, subsidies as a governmental incentive measure were created to support the development and growth of the renewable energy industry. At present, there are many problems with China's renewable energy subsidy policy in practice, such as fragmented institutional policies, lack of procedural regulations, and lagging subsidy funds. The excellent legislative practice experience of foreign countries can be borrowed by China to make up for the corresponding loopholes and, on the basis of fully examining the specific conditions of China, to promote the progressive reform of China's renewable energy subsidy system; form a trinity system of law, general strategy, and specific policies; strengthen collaboration; and enhance its scientific level. At the same time, China can actively broaden the sources of subsidy funds, explore diversified financing methods, further standardize the subsidy procedures, strengthen the supervision in implementation, and enhance the efficiency of the utilization of funds, so as to enhance the legalization of the subsidy system. [ABSTRACT FROM AUTHOR]

The current legal and policy system of renewable energy in China has set up a framework of policy instruments, which provides an important foundation for dealing with climate change and promoting the healthy development of the renewable energy industry with the goal of "carbon neutrality" and "emission peak". However, the current policy instruments cannot meet the needs for rapid development of the renewable energy industry. This paper investigates, analyzes, and concludes the status of renewable energy development along with related policy instruments in different renewable energy sources by literature and points out the problems of current policy instruments, and puts forward corresponding countermeasures. Moreover, from the perspective of energy consumption market transformation, the authors carried out an analysis of China's challenges of policy instruments, pointing out that China's renewable energy policy instruments have the potential to take one step further in the areas of the regulatory system, legal system and legal security system. [ABSTRACT FROM AUTHOR]

Currently, the issue of natural flammability of unsaturated polyester resin (UPR) severely restrains its application. In this study, polymeric flame retardant poly methyl vinyl di (1-thio-2,6,7-trioxal-1-phosphabicyclo [2.2] octane-4-methoxy) silane (PMVDOS) with P–S–Si-based cage unit was synthesized. The UPR/PMVDOS composites were prepared by adding different ratios of PMVDOS into UPR. The flame-retardant properties and the char layer structure of UPR samples were evaluated via the limiting oxygen index (LOI), vertical burning test, cone calorimeter test, scanning electron microscopy, laser Raman spectroscopy, and X-ray photoelectron spectroscopy. The results showed that UPR/PMVDOS composites reached the UL-94 V-0 rating with the LOI value of 27.8%, and the carbon residue increased from 4.9% for pure UPR to 14.9% when the content of PMVDOS was 18 wt%. The peaks of heat release rate, total heat release, and total smoke production were comparatively reduced. The flame-retardant mechanism of PMVDOS mainly acted on the condensed phase. The surface of the matrix was covered with the polymer containing phosphorous and silicon dioxide particles, preventing the escape of flammable volatiles and isolating the exchange of oxygen and heat, thus, the degradation of the matrix could be inhibited. This research provides a solution to improve the flame retardancy of UPR. [ABSTRACT FROM AUTHOR]

Changes in heart structure and function after lung resection in patients with lung cancer are challenging to manage. Therefore, a non-invasive and reliable measurement tool to gauge such changes is critical. The purpose of the present study was to compare cardiological changes before and after lung resection using tissue Doppler imaging (TDI). A total of 43 patients (19 men and 24 women) with primary non-small cell lung cancer (n=37) and metastatic cancer in the lungs (n=6) were enrolled in the study.nTDI was used to determine the thickness of the ascending aorta, the open size of the ascending valve, the anterior-oposterior diameters of the left atrium and left ventricle, and the thickness of the ventricular septum and right ventricle before and after lung resection. Left ventricular (LV) ejection fraction (EF), pulmonary valve flow rate, tricuspid annular or mitral leaflet tip early (E) peak/late (A) diastolic blood flow velocities, tricuspid regurgitation flow, the lateral mitral annulus early (e') diastolic velocity and mitral E/e' ratio were used to determine LV filling pressure. Results revealed no significant differences between male and female patients in terms of the open size of the ascending valve, the anterior-posterior diameter of the left ventricle and the mitral E/e' ratio. Significant differences were found in the width of the ascending aorta, anterior-posterior diameter of the left atrium, width of the LV septum and right ventricular (RV) diameter before and after lung resection. Finally, there were significantchanges in EF and tricuspid pressure. The results indicated that TDI was useful as a non-invasive method for assessing left and right heart function following lung resection. The LV and RV dimensions were affected, but LV filling pressure was preserved after lobectomy. [ABSTRACT FROM AUTHOR]

In light of the situation of sliced or powdery cuttings produced by conventional PDC bit, it is found that they are not convenient for geological logging and stratification. The unit crushing experiment which contains two breaking forms (static-pressure breaking and impact) is conducted on core columns of sandstone, limestone, and granite. This experimental study showed the following: The breaking work ratio of the three core column types is much less than that of the flat rock. The height of the core column has little effect on the bit penetration rate, while core column diameter has greater effect on the bit penetration rate. The experimental results further indicate that a core column has been generated in the central area of the drill bit, which is beneficial to the volume breaking of the rock and can improve the rock-breaking efficiency of the drill bit. The microcoring bit is suitable for raising speed in soft, medium, and hard formations and is helpful for geological logging. [ABSTRACT FROM AUTHOR]

Twin-tool synchronous milling is a new method for blade machining which can improve the machining efficiency obviously. It can be realized on a nine-axis machine tool with two cutters. However, the kinematic analysis and the feedrate planning are more difficult, due to the more complex structure than the traditional five-axis machine tool. In this paper, an efficient postprocessor algorithm is developed and feedrate optimization method is proposed to realize twin-tool synchronous milling. Based on a brief structure and kinematic chain analysis, the generalized kinematic model is built. Considering the characteristics that the A-axis is shared by two cutters in the nine-axis machine tool, the mathematical formulas of the motion coordinates and rotary angles are derived, which can simultaneously transform the location and orientation vectors of the two cutters into numerically controlled (NC) codes. Meanwhile, the feedrate is planned to maintain the simultaneous cutting with the two cutters, even though the displacements between adjacent cutting contact points on the opposite blade surfaces are unequal. Then, the feedrate optimization strategy is proposed to guarantee the continuity of the cutting speed; the saturation limit for each servo motor is also considered. Furthermore, the NC codes for machining a typical turbine blade are generated with the developed postprocessor algorithm, then the velocity and acceleration of each axis at different cutter-contact-point are calculated. The validity is demonstrated with simulation and experiments on a self-developed nine-axis machine tool. [ABSTRACT FROM AUTHOR]

We demonstrate an environmentally stable femtosecond laser for industrial application based on all polarization‐maintaining Yb‐doped laser and experimentally explore the effect of the net cavity dispersion (NCD) on output characteristics. The oscillator emits pulses with 5.1 ps and a 23 nm spectral bandwidth, then the pulse is compressed to 88 fs. The instabilities over 120 h gives 0.32% relative root mean square noise, indicating high stability of the pulse laser. With effective regulation of NCD, we obtained the maximum spectral bandwidth of 27 nm. Such broadband oscillator with compact all‐fiber configurations provide extremely high stability should be very attractive for long‐term industrial application. [ABSTRACT FROM AUTHOR]

• The injury severity levels of both drivers involved in the same truck-car crash are investigated simultaneously. • A novel random parameters bivariate probit model with heterogeneity in means and variances is used in this study. • The model suggests a positive relationship between both drivers involved in the same truck-car crash. • The effects of the explanatory factors that exhibit relative temporal stability are found to vary across vehicle-type crashes. • Key risk factors are identified and corresponding countermeasures are proposed. Truck-involved crashes, especially truck-car crashes, are associated with serious and even fatal injuries, thus necessitating an in-depth analysis. Prior research focused solely on examining the injury severity of truck drivers or developed separate performance models for truck and car drivers. However, the severity of injuries to both drivers in the same truck-car crash may be interrelated, and influencing factors of injury severities sustained by the two parties may differ. To address these concerns, a random parameter bivariate probit model with heterogeneity in means (RPBPHM) is applied to examine factors affecting the injury severity of both drivers in the same truck-car crash and how these factors change over the years. Using truck-car crash data from 2017 to 2019 in the UK, the dependent variable is defined as slight injury and serious injury or fatality. Factors such as driver, vehicle, road, and environmental characteristics are statistically analyzed in this study. According to the findings, the RPBPHM model demonstrated a remarkable statistical fit, and a positive correlation was observed between the two drivers' injury severity in truck-car crashes. More importantly, the effects of the explanatory factors showing relatively temporal stability vary across different types of vehicle crashes. For example, car driver improper actions and lane changing by trucks, have a significant interactive effect on the severity of injuries sustained by drivers involved collisions between trucks and cars. Male truck drivers, young truck drivers, older truck drivers, and truck drivers' improper actions, elevate the estimated odds of only truck drivers; while older car and unsignalized crossing increase the possibility of injury severity of only car drivers. Finally, due to shared unobserved crash-specific factors, the 30-mph speed limit, dark no lights, and head-on collision, significantly affect the severity of injuries sustained by drivers involved in collisions between trucks and cars. The modeling approach provides a novel framework for jointly analyzing truck-involved crash injury severities. The findings will help policymakers take the necessary actions to reduce truck-car crashes by implementing appropriate and accurate safety countermeasures. [ABSTRACT FROM AUTHOR]

MAO coating is a significant research topic to improve the corrosion resistance of Mg alloys, which are currently being received much attention. The majority of current research is centered on optimizing the pore structure of MAO coatings to improve corrosion resistance, but the bonding between the coating and the substrate has been neglected. In this work, MAO coatings with different porosity and adhesion strength were obtained in phosphate and silicate electrolytes at different voltages. The structure, chemical composition, and mechanical properties of MAO coatings were also analyzed by various means, and their corrosion resistance was tested by electrochemical metholds. The influence of porosity and adhesion on the corrosion resistance of the coatings was analyzed and their mechanism has been examined, which is beneficial to obtain longer corrosion resistance MAO coating. [Display omitted] • The corrosion failure progress and mechanism of MAO coating prepared in different electrolytes has been studied. • The key factors affecting the corrosion resistance of microarc oxidation coating has been studied. • Enhanced adhesion strength can improve the corrosion resistance of MAO coatings. [ABSTRACT FROM AUTHOR]

• Chronic arsenic exposure only causes initial increase of inorganic arsenic in marine medaka. • The increased inorganic arsenic levels induce oxidative stress and antioxidant enzymes response. • The arsenic bioaccumulation was poor due to low uptake and high efflux. Arsenic (As) is a highly toxic metalloid to aquatic organisms, but the effects of low-dose chronic inorganic As exposure on marine fish are still unclear. A 28-day study was conducted on chronic exposure of 100 μg/L inorganic As [As(III) and As(V)] in the marine medaka Oryzias melastigma to quantify the effects of chronic inorganic As exposure on its bioaccumulation, biotransformation, oxidative stress, and antioxidant enzymes response. During the exposure period, chronic inorganic As exposure had no significant effect on the total As bioaccumulation except at 7 d for As(V) treatment. Based on the toxicokinetic data, the low As bioaccumulation was caused by low dissolved uptake (k u), internal transfer (k 12 , k 21) and high efflux (k e1). The organic As were the predominated species (77 − 80%) and remained constant, while the inorganic As increased 35% (from 0.26 μg/g to 0.35 μg/g) during the initial 4-d exposure and then recovered. The increased inorganic As could be covered by the high contribution of organic As especially arsenobetaine (AsB) to the total As accumulation. Coincidently, the malondialdehyde (MDA) levels followed similar trends as the inorganic As concentrations, indicating that inorganic As bioaccumulation induced oxidative stress at the initial stage. Both the contents of the nonenzymatic antioxidant (glutathione, GSH) and the activities of the enzymatic antioxidants (superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and glutathione- S -transferase (GST)) increased initially and then decreased as the inorganic As concentrations, thus lowering the hydrogen peroxide (H 2 O 2) levels and displaying a typical antioxidant defense mechanism. In summary, this study elucidated that although the marine medaka had a limited ability to accumulate waterborne As, the increase in the inorganic As at the early stage of exposure still caused toxic effects, which could be ignored by constant total As concentrations. Therefore, the toxicity of As could be underestimated if only the total As instead of the inorganic As is monitored in marine fish. [ABSTRACT FROM AUTHOR]

Abstract The effects of alternating current (AC) and Bacillus cereus (B. cereus) on the stress corrosion behavior and mechanism of X80 pipeline steel were investigated in a Beijing soil solution in this study. Both AC and B. cereus can promote the generation of pits in X80 steel. B. cereus is a type of nitrate-reducing bacteria and hence nitrate reduction occurs at the bottom of the corrosion product film or the biofilm. Meanwhile, the anode accelerates the dissolution of X80 steel and generates some pits in the local working area. The synergistic effect of AC and nitrate- reducing bacteria (NRB) promotes X80 steel corrosion and increases its susceptibility to stress corrosion cracking (SCC). Highlights • B. cereus as a nitrate-reducing bacterium reduced nitrate into NH 4 +. • AC and B. cereus synergy promoted X80 steel corrosion. • Both AC and B. cereus increased pitting and stress corrosion cracking susceptibility. [ABSTRACT FROM AUTHOR]

Twin-tool milling is a new method for turbine blade machining. The dorsal and basin surfaces are machined simultaneously, which can improve the machining efficiency obviously. However, its tool path planning becomes a major challenge due to the asymmetry of the blade surfaces and the structural constraints of the twin-tool machine. In this paper, an iso-parametric path-planning method is proposed for turbine blades milling with twin tools. Considering the structural constraints, the twin-tool orientations are characterized uniformly. In order to guarantee the smoothness of the tool paths, the calculating and equally parameterized fitting algorithm for the cutter contact (CC) points in each path is proposed. Furthermore, the opposite tool paths are matched with a self-defined ratio to realize the simultaneous milling for both blade surfaces. Finally, the tool paths are planned for a typical turbine blade based on the method. The results of simulation and verification experiments show that both blade surfaces are entirely machined. The contour errors can meet the tolerance requirements. In addition, the efficiency increases by about 45% compared with the single-tool milling of the equivalent cutting parameters. [ABSTRACT FROM AUTHOR]

Hydrogen embrittlement in hydrogen pipelines can cause severe economic losses and safety hazards, thus research on efficient hydrogen barrier coatings is of great importance. In this study, a more efficient and easily operable non-covalent modification method was employed to modify carboxymethyl chitosan (CMCS) onto graphene oxide (GO), resulting in a significant improvement in the dispersibility and uniform distribution of GO in waterborne epoxy resin. Subsequently, a hydrogen barrier coating was prepared by incorporating the modified GO into waterborne epoxy resin. The influence of different doping concentrations on the coating performance was investigated. The basic properties of the coatings were characterized using macroscopic analysis, SEM, contact angle measurements, adhesion tests and electrochemical techniques. The corrosion resistance and hydrogen barrier effect was evaluated through electrochemical hydrogen permeation experiments. Results showed that The modified graphene oxide has good compatibility with epoxy resin. When the content of CGO was 0.25 %, the dispersion was best. the CGO coatings has some corrosion resistance with approximately 10 MPa adhesive force and 105 Modular value at the beginning of immersion. The CGO coatings significantly improved the hydrogen resistance of ×80 steel. The lowest hydrogen permeation current density was observed at 0.25 wt% CGO concentration, which indicated optimal hydrogen permeation inhibition capability. • The graphene oxide (GO) has been modified to CGO by carboxymethyl chitosan. • 0.25%CGO was best dispersed in the epoxy resins. • The CGO complex coating has some corrosion resistance. • The 0.25%CGO coating has superior hydrogen resistance performance. [ABSTRACT FROM AUTHOR]

The corrosion of X80 pipeline steel in the presence of Bacillus cereus ( B . cereus ) was studied through electrochemical and surface analyses and live/dead staining. Scanning electron microscopy and live/dead straining results showed that a number of B . cereus adhered to the X80 steel. Electrochemical impedance spectroscopy showed that B . cereus could accelerate the corrosion of X80 steel. In addition, surface morphology observations indicated that B . cereus could accelerate pitting corrosion in X80 steel. The depth of the largest pits due to B . cereus was approximately 11.23 μm. Many pits were found on the U-shaped bents and cracks formed under stress after 60 days of immersion in the presence of B . cereus . These indicate that pitting corrosion can be accelerated by B . cereus . X-ray photoelectron spectroscopy results revealed that NH 4 + existed on the surface of X80 steel. B . cereus is a type of nitrate-reducing bacteria and hence the corrosion mechanism of B . cereus may involve nitrate reduction on the X80 steel. [ABSTRACT FROM AUTHOR]

The influence of various negative half-wave alternating current (AC) densities on the stress corrosion cracking (SCC) behavior and mechanism of X80 pipeline steel (widely used in West-East natural gas transmission) was investigated in typical NS4 near-neutral solution (used to simulate the electrolyte trapped under a disbonded coating) by data acquisition technique, electrochemical method, immersion tests, slow strain rate tensile tests, and surface analysis techniques. It was found that the negative half-wave AC could accelerate corrosion of the steel for the potential decreasing, current density increasing and generating the local anodic dissolution such as nucleated pits. The SCC susceptibility of X80 steel was relatively high for disturbing the local double-charge layer structure at 5 A·m −2 current density. Besides, the negative half-wave AC could promote cathodic hydrogen evolution reaction, the SCC susceptibility was low for hydrogen-induced plasticity at 10 and 20 A·m −2 and the SCC mechanism was collectively controlled by anodic dissolution (AD) and hydrogen embrittlement, but it was elevated for the hydrogen-induced local anodic dissolution and hydrogen-induced embrittlement above 30 A·m −2 and the SCC mechanism was hydrogen embrittlement. [ABSTRACT FROM AUTHOR]

The effects of multiwalled carbon nanotubes (MWCNTs) on the adhesion strength and corrosion resistance of the acrylic nanocomposite coatings were evaluated on Q235 substrates via pull-off tests and electrochemistry measurements (EIS, LEIS). Addition of MWCNTs to the acrylic resulted in an up to ∼50% increase in the adhesion strength. After 36 h of immersion in 3.5 wt% NaCl, the coating resistance of the native acrylic coating was 235.8 Ω cm 2 , whereas those of the nanocomposite coatings containing 0.5 and 1 wt% MWCNTs were 1.36 × 10 5 and 9.27 × 10 7 Ω cm 2 , respectively. LEIS analysis indicated that the addition of MWCNTs increased the adhesion strength and retarded the delamination. The results demonstrated the positive effects of the incorporation of MWCNTs on the anticorrosive ability of the coatings. [ABSTRACT FROM AUTHOR]

Organic conductive coating/plasma electrolytic oxidation (PEO) coating/Mg-RE alloy is a simple way to meet the functional requirements and service safety of electronic equipment. In this work, the Macro electrochemistry, micro electrochemistry and mechanical test were performed to study the corrosion failure process of organic conductive coatings and PEO coating on the surface of Mg-RE alloy under the harsh marine atmospheric environment. Organic conductive coatings have protective effect on Mg-RE with PEO coating (the impedance modulus remain higher than 106 at low frequencies during 21d immersion, and the characteristics of EIS remained constant). But local failure of bonding between organic conductive coating and PEO coating were occurred after being immersed in Xisha simulation solution and it weakened the long-term protection ability of organic conductive coating/PEO coating/Mg-RE alloy system, which limited long-term corrosion resistance. [Display omitted] • Corrosion failure process of organic conductive coatings on Mg-RE alloy were studied. • The characteristic of corrosion failure process of coatings had been recorded. • Both organic conductive coatings have protective effort for Mg-RE with PEO coating. • Local failure of bonding was the main reason of corrosion failure. [ABSTRACT FROM AUTHOR]

The self-sharpening vitrified-metal bond diamond wheels added with a 3 wt.% brittle Na 2 O-B 2 O 3 -SiO 2 -Al 2 O 3 -Li 2 O vitrified bond were fabricated by hot pressed sintering technique. Using the methods of scan-electroscope, energy spectrum analysis, X-diffraction analysis, XPS analysis, Rockwell hardness test and three-point bending test, the effects of hot pressing temperature on the microstructure, hardness and the transverse rupture strength (TRS) of vitrified-metal bond were investigated. Then the grinding performance of cylinder of the diamond wheels was also studied. The results showed that, when the hot pressing temperature was 850 °C, a thin FeAl 2 O 4 transition layer formed, which enhanced the interfacial bending strength between metal and glass phase, and the TRS of vitrified-metal bond reached the maximum value 826.54 MPa. Comparing with metal bond diamond wheel's, the average value of the roundness and straightness of the 50 cylinders ground by the vitrified-metal diamond wheel reduced from 3.1 μm and 2.5 μm to 2.7 μm and 2.1 μm. [ABSTRACT FROM AUTHOR]

The rapid rise of China as a dominant global player in the solar photovoltaic industry has drawn much attention from scholars and policy-makers. However, few literatures have launched an in-depth analysis of China׳s strategic promotion of the photovoltaic industry. This study aims to fill this gap. This paper investigates legislative and policy development along with industrial strategies which the Chinese government has pursued in order to encourage development in the photovoltaic industry and also in related research and development activities. Moreover, from the perspective of technological and industrial development trends, the authors carried out an analysis of China׳s photovoltaic industry chain, pointing out that China׳s photovoltaic industry has the potential to take one step further in the areas of research and development, and the possibility of achieving breakthroughs in international cooperation. [ABSTRACT FROM AUTHOR]

Corrosion and hydrogen damage cause problems to oil and gas industry equipment. FeS (sulfur-iron) compounds generated by H 2 S causes surface corrosion and covers the surfaces of the equipment where the extent of corrosion and hydrogen damage are influenced by these compounds. Different types of FeS compounds have different crystal structures, and there by influence their corrosion and hydrogen resistance. In this paper, single-structure pyrrhotite and pyrite were synthesized by hydrothermal method, which was controlled by controlling the temperature and Fe, S ratio. Their structures are hexagonal sheet and polyhedron respectively. The interfacial properties and hydrogen barrier properties of FeS were tested and the results show that pyrrhotite possesses anion selectivity. The electrochemistry shows low impedance modulus and high corrosion current density, which indicates low corrosion resistance. Pyrrhotite has the lowest hydrogen permeation current density and has good inhibition of hydrogen permeation ability. For the high impedance modulus and low corrosion current density pyrite possesses cation selective, which shows strong resistance to corrosion. However, its hydrogen permeation current density is high and hydrogen blocking effect is weak. • The hydrothermal method was used to obtain pure FeS. • The structures of pyrrhotite and pyrite are the same with FeS generated in H 2 S environment. • Pyrrhotite possesses anion selectivity and pyrite possesses cation selectivity. • The hydrogen barrier effect of pyrrhotite is better than pyrite. [ABSTRACT FROM AUTHOR]

To predict the service life of polystyrene (PS) under an aggressive environment, the nondimensional expression Z was established from a data set of multiple properties of PS by principal component analysis (PCA). In this study, PS specimens were exposed to the tropical environment on Xisha Islands in China for two years. Chromatic aberration, gloss, tensile strength, elongation at break, flexural strength, and impact strength were tested to evaluate the aging behavior of PS. Based on different needs of industries, each of the multiple properties could be used to evaluate the service life of PS. However, selecting a single performance variation will inevitably hide some information about the entire aging process. Therefore, finding a comprehensive measure representing the overall aging performance of PS can be highly significant. Herein, PCA was applied to obtain a specific property (Z) which can represent all properties of PS. Z of PS degradation showed a slight decrease for the initial two months of exposure after which it increased rapidly in the next eight months. Subsequently, a slower increase of Z value was observed. From the three different stages shown as Z value increases, three stages have been identified for PS service life. [ABSTRACT FROM AUTHOR]

The protective performance, in conditions of total immersion, of an acrylic water-based paint applied to rusty steel, has been studied using electrochemical techniques. There was no rust, blister, crack, or flake that occurred on coating after 500 h immersion. The data obtained have enabled the protective mechanism to be proposed. The specific pigments utilized in the formulation of the paint studied can release phosphates to form a protective layer on metal substrate, which can impede the access of aggressive species to substrate surface. The coatings performed electrochemical activity in the beginning of immersion; then the layer formed and resistance of coating increased. [ABSTRACT FROM AUTHOR]

Abstract: To evaluate the aging behavior of polypropylene (PP) under an aggressive environment, principal component analysis (PCA) was used to establish a non-dimensional expression Z from a data set of multiple properties of PP. In this study, PP specimens were subjected to natural exposure under the tropical environment on Xisha islands in China for different time periods. Chromatic aberration, gloss, tensile strength, elongation at break, flexural strength and impact strength were tested to evaluate the aging behavior of the PP. Principal component analysis (PCA) was then used to find a specific property to represent all properties of PP. The combined evaluation parameter Z of PP degradation showed no change for the initial two months of exposure. After a sharp increase, the value of Z increased gradually and finally leveled off for the last two months. Based on the Z values, the effect of solar radiation intensity on the degradation of PP is discussed. [Copyright &y& Elsevier]

As one of the world's largest energy consumers, China is facing the challenge of growing energy demand. Under this background, China is actively implementing the concept of green development and sustainable development route. As inexhaustible green energy, solar energy, has been established as an independent energy type by the Renewable Energy Law and has a broad development prospect. At present, the industrialization level of photovoltaic manufacturing in China is constantly improving, and the efficiency of photovoltaic power generation is constantly improving. However, from the perspective of the system, China's photovoltaic industry supporting legal system is not perfect. There is a mismatch between the existing laws and industrial development needs, which restricts the future development of photovoltaic power generation in China. The legal environment is crucial to the development of a country's relevant industries. Only with a good supporting legal system can the development and utilization of solar energy be carried out reasonably and orderly. The PV industry legislation should be adjusted and responded to in a timely manner according to the development situation of the PV industry and the PV market, so as to speed up the introduction of core laws in the PV field, continuously improve the supporting legal system, and effectively play the role of institutional protection of the law. [ABSTRACT FROM AUTHOR]

• Design taper tooth for the failure of the tooth loss. • A device is designed to study axial/ transverse loads on taper teeth at different taper. • The taper, transverse load and interference magnitude contribute to failure. • The taper tooth also solves the tooth dropping in high geothermal drilling. In view of the tooth dropping phenomenon caused by the complex formation and other factors of the cone bit, a taper structure tooth is proposed. Experimental research on the strength of the proposed taper tooth was performed to study the influence of taper, interference, and transverse force on tooth fixation strength. The experimental results show that for different tapers (C50, C100, C200, C300, and C400), the maximum fastening force corresponds to an interference of 0.095 mm, and is 5.39–85.36% higher than that of a conventional cylindrical tooth, and the maximum fastening force is 30.25 kN for a C50 taper. Simulation results by the finite element method, were within 10% of the experimental results, verifying the simulation model. Through the numerical simulation of the tapered and cylindrical teeth at different temperatures, it is concluded that tapered teeth have better fixation strength than the cylindrical teeth, which can greatly improve the drilling efficiency of the cone bit in conventional and high-temperature drilling. [ABSTRACT FROM AUTHOR]

Travelers often change their behavior in reaction to adverse weather conditions. This paper seeks to conduct an empirical evaluation of both ordered and unordered discrete outcome frameworks for examining the adaptive behavior decisions of intercity travelers and investigate the varying effects of explanatory factors on different alternatives of adaptive behavior during adverse weather. The data from 754 respondents in the Beijing-Tianjin-Hebei urban agglomeration, China are collected by a two-phase survey instrument. To capture the unobserved heterogeneity more effectively, this paper develops three advanced models to investigate the variations in intercity travel behavior during adverse weather. Four alternative adaptive behaviors are determined as outcome variables: maintaining original travel plans, changing only the intercity mode, changing the departure date, and canceling the trip, while potential influencing factors including adverse weather conditions, trip-related characteristics, individual attributes and urban agglomeration attributes are statistically assessed. The results indicate that the unordered models consistently outperform their ordered counterparts, and the incorporation of multilayer heterogeneity enhances the model fit. Furthermore, significant factors and their coefficient values vary across the different adaptive behavior alternatives. Intercity travelers demonstrate a higher probability of changing departure dates or canceling trips during snowy and windy days compared to rainy and foggy days. Trains exhibit higher flexibility and reliability during adverse weather, and access attributes significantly affect intercity travel adaptive behavior. Additionally, the analysis of individual and urban agglomeration attributes uncovers variations in adaptive behavior among individuals and cities. These findings provide profound insights into the complexities and variations of intercity travel behavior during adverse weather, and propose practical strategies to mitigate the detrimental impacts of adverse weather on intercity travelers. • Adaptive behavior of intercity travelers during adverse weather is investigated. • Unordered framework outperforms ordered counterparts in adaptive behavior study. • Multilayer unobserved heterogeneity in the adaptive behavior is accounted for. • The varying effects of explanatory factors on different adaptive alternatives are examined. • Practical strategies are proposed to mitigate negative impacts of adverse weather. [ABSTRACT FROM AUTHOR]

Purpose: The impact of rolling on the performance of micro arc oxidation (MAO) coatings on ZM5 alloy has been underreported. The purpose of this study is to explore the correlation between rolling and the failure mechanism of MAO coatings in greater depth. Design/methodology/approach: The influence of rolling on the corrosion and wear properties of MAO coating was investigated by phase structure, bond strength test (initial bond strength and wet adhesion), electrochemical impedance spectroscopy and wear test. The change of the surface electrochemical properties was studied by first principles analysis. Findings: The results showed that the MAO coating on rolled alloy had better corrosion and wear resistance compared to cast alloy, although the structure and component content of two kinds of MAO coating are nearly identical. The difference in interface bonding between MAO coating and Mg substrate is the primary factor contributing to the disparity in performance between the two types of samples. Finally, the impact of the rolling process on MAO coating properties is explained through first-principle calculation. Originality/value: A comprehensive explanation of the impact of the rolling process on MAO coating properties will provide substantial support for enhancing the application of Mg alloy anticorrosion. [ABSTRACT FROM AUTHOR]

• The full wave AC was divided into negative half wave and positive half wave AC to investigate the corrosion mechanism. • Crack propagation experiment was designed to study the effect of AC on ion migration. • How AC improving X80 pipeline steel SCC susceptibility was studied through finite element model. This paper studied the mechanism of alternating current (AC) promoting corrosion and improving SCC susceptibility in near-neutral pH solution. It was found that AC can result in local corrosion. X80 steel generated some pitting under the effect of full wave AC for the anodic dissolution. Some acuity pitting generated due that hydrogen induced anodic dissolution for negative half-wave AC. However, X80 steel generated some larger radius pitting for the positive half wave AC which was related to anodic dissolution. AC can facilitate ion migration from the result of crack propagation experiment. The SCC susceptibility of X80 steel in NS4 near neutral pH solution was negative half wave AC > full wave AC > positive half wave AC. The finite element results showed that AC can promote hydrogen precipitation. AC promoted X80 steel corrosion for facilitating ion migration and improved SCC susceptibility for assisting hydrogen precipitation. [ABSTRACT FROM AUTHOR]

• The EIS technique combined with LEIS technique was used to study the failure process of waterborne acrylic coating. • The effects of defect size, chloride ion concentration and resin type on failure process of waterborne acrylic coating were investigated. • The key factor in the failure process of the waterborne coating were studied by compared two types of waterborne acrylic coating during immersion. Cathodic delamination—weakening or loss of adhesion between the coating and the metal—is one of the major failure processes of organic coatings. Generally, it is almost inevitable to introduce defects to the coating during processing and operation. In this work, the delamination process of coatings around defects and the corrosion in defective coated metals was elucidated using immersion and electrochemical impedance tests. Two types of coatings (styrene-acrylic coating and terpolymer coating) were compared. The effects of defect size, chloride ion concentration and resin type on cathodic delamination were investigated. A small defect may affect the metal corrosion. Increasing the chloride ion concentration can promote the corrosion of metal but may not accelerate the delamination of the coating. The resin type is the key factor in the failure process of the coating. [ABSTRACT FROM AUTHOR]

The failure of an impregnated bit used in the Xujiahe formation was analyzed, and the major factors determining bit failure were diamond granularity and concentration. Micro-drilling tests with impregnated cutters of different diamond granularities and concentrations were conducted. The results show that the cutting efficiency of cutting elements decreases with increasing diamond granularity increases with increasing diamond concentration; the wear resistance of cutting elements increases with increasing diamond granularity with increasing diamond concentration. Based on a comprehensive analysis of the test results, the optimum formulation parameters of diamond granularity and concentration were determined to achieve the best cutting efficiency and wear resistance, and a new impregnated bit was designed and tested in the Xujiahe formation, which has a footage of 88.46 m, rate of penetration (ROP) of 1.38/h, and drilling time of 64.19 h, which were 74.3%, 30%, and 35.1% higher, respectively. Compared with conventional impregnated bits, the cutting efficiency and working life of the new impregnated bit are significantly increased, providing technical support to efforts to increase the ROP of impregnated bits in complex and highly abrasive formations in west Sichuan and Xinjiang. • The optimum formula of cutting efficiency and wear resistance of the impregnated bit is obtained. • The impregnated cutter with a diamond granularity of 30–35 mesh and diamond concentration of 150% is optimal. • The footage, ROP, and drilling time of the new impregnated bit improved 74.3%, 30%, and 35.1% respectively. [ABSTRACT FROM AUTHOR]

Latent fingerprints (LFPs) is one of the most important physical evidence in the criminal scene, playing an important role in forensic investigations. Therefore, developing highly sensitive and convenient materials for the visualization of LFPs is of great significance. We designed and synthesized an organic fluorescent molecule TP-PH with aggregation-induced enhanced emission (AIEE) activity. By simply soaking, blue fluorescent images with high contrast and resolution are readily developed on various surfaces including tinfoil, steel, glass and plastic. Remarkably, LFPs can be visualized within 5 min including the first-, second- and tertiary-level details. In addition, TP-PH exhibits interesting photoactivated fluorescence enhancement properties. Under irradiation of 365 nm UV light with a power density of 382 mW/cm2, the fluorescence quantum yield displays approximately 21.5-fold enhancement. Mechanism studies reveals that the photoactivated fluorescence is attributed to the irreversible cyclodehydrogenation reactions under UV irradiation. This work provides a guideline for the design of multifunctional AIEE fluorescent materials. [ABSTRACT FROM AUTHOR]

The causes analysis of road traffic accidents is often modelled based on high-dimensional small-sample data; however, such models often have low predictive accuracy and poor generalization performance. An analytical framework that considers both data augmentation and model optimization can enhance variable interpretation and predictive model performance, thereby improving the shortcomings of existing accident analysis methods. Our approach is as follows: 1) Starting with an analysis of the nature of road accidents, a symbolic operation is used to design a feature crosses algorithm. A random variable is added to construct a quantifiable feature selection algorithm, which can form a data augmentation method that conforms to the accident rules. 2) A highly reliable framework for analysing accident causes is constructed by using forward selection to optimize an ensemble learning model subset combined with feature crosses, feature selection and multiple-classification algorithms. A case study with accident data from a city in China shows that ensemble learning has the advantages of high predictive accuracy and strong generalization performance. It can accurately identify the key causes of accidents based on highly dimensional small-sample data. Driving behaviours such as lane changes and turns are the key causes of accidents. Giving drivers effective traffic environment information in a timely manner can significantly improve driving performance and reduce accident risk. This research provides a reference for the analysis of road accidents. [ABSTRACT FROM AUTHOR]

• Determinants of motorcyclists' injury severities are studied. • Methodological issues of scale and random heterogeneity are captured. • Mixed logit models considering generalized scale heterogeneity are estimated. • Random parameters logit model considering heterogeneity in means and vaeiances are also estimated. • Temporal instability warrants for estimation of separate year-specific models. • Significant differences in sources of heterogeneity over the years are observed. The presence of unobserved factors in the motorcycle involved two-vehicle crashes (MV) data could lead to heterogenous associations between observed factors and injury severity sustained by motorcyclists. Capturing such heterogeneities necessitates distinct methodological approaches, of which random and scale heterogeneity models are paramount. Herein, we undertake an empirical evaluation of random and scale heterogeneity models, exploring their efficacy in delineating the influence of external determinants on the degree of injury severity in crashes. Within the effects of scale heterogeneity, this study delves into two dominant models: the scaled multinomial logit model (S-MNL) and its generalized counterpart, the G-MNL, which encompasses both the S-MNL and the random parameters multinomial logit model (RPL). While the random heterogeneity domain is represented by the random parameters multinomial logit and an upgraded variant – the random parameters multinomial logit model with heterogeneity in means and variances (RPLHMV). Motorcycle involved two-vehicle crashes data were extracted from the UK STATS19 dataset from 2016 to 2020. Likelihood ratio tests are computed to assess the temporal variability of the significant factors. The test result demonstrates the temporal variations over a five-year study period. Some very important differences started to show up across the years based on the model estimation results: that the RPLHMV model statistically outperforms the G-MNL model in the 2016, 2018, and 2019 models, while the S-MNL model is statistically superior in the 2017 and 2020 years. These important findings suggest that the origin of heterogeneity in explaining factor weights can be captured by scale effects, not just random heterogeneity. In addition, the model results further show that motorcyclists' injury severities are significantly affected by motorcycle-related characteristics; there is the added factor of external influences, such as non-motorcycle drivers (males, young drivers, and elderly drivers) and vehicles (the moving status, age, and types of vehicles) that collide with motorcycles. The results of this paper are anticipated to help policymakers develop effective strategies to mitigate motorcycle involved two-vehicle crashes by implementing appropriate measures. [ABSTRACT FROM AUTHOR]

Roadside barriers have proven effective in preventing run-off-road accidents that occurred in mountainous areas. Nonetheless, the influence of variables impacting the severity of injuries resulting from collisions involving distinct types of roadside barriers may diverge. This study delves into the factors that influence the severity of driver's injuries in crashes encompassing three specific varieties of roadside barriers in mountainous regions, namely, W-beam barriers, flexible barriers, and roadside trees. The evolution of these factors over time is examined through the application of a random parameters logit modeling approach with heterogeneity in means and variances (RPLHMVs). By employing injury-severity data from 2016 to 2019 for the mountainous regions of a city in Southwest China, various potential influencing factors encompassing driver-, vehicle-, road-, and environment-specific characteristics are subjected to statistical analysis. The extent of the impact of identified statistically significant factors on driver's injury severity is assessed through the computation of pseudoelasticities. The findings reveal distinctions in the outcomes of driver's injury severity contingent upon the type of roadside barrier encountered during vehicle impacts. To illustrate, collisions involving W-beam barriers are more prone to result in severe injuries. Moreover, the influence of variables determining driver's injury severity displays noteworthy temporal shifts. Notably, the pseudoelasticities of numerous explanatory variables remain temporally consistent for incidents involving flexible or roadside barriers. In contrast, crashes involving W-beam barriers highlight that solely the speeding indicator demonstrates temporally stable pseudoelasticities. The insights garnered from this investigation offer the potential to contribute to the formulation of fresh guidelines for the design and selection of roadside barriers aimed at mitigating the severity of injuries incurred in crashes within mountainous regions. [ABSTRACT FROM AUTHOR]

• Injury severities of expressway crashes in 3 types of tunnels were estimated. • Two unobserved heterogeneity models were adopted to obtain robust results. • Certain differences exited in the contributing factors in the 3 types of tunnels. • Likelihood ratio tests and out-of-sample predictions were investigated. • Several targeted countermeasures were provided for eliminating injury severities. This study examines the non-transferability of the determinants affecting injury severities of tunnels of three grades classified by different lengths. Based on tunnel crash data in Shanxi Province during (2012–2018), three possible crash injury severity categories (no injury, minor injury, and severe injury) are estimated. Two alternate models were used to account for unobserved heterogeneity: a random parameters multinomial logit (RPML) model with heterogeneity in means and variances and a latent-class multinomial logit (LCML) model with class probability functions. Non-transferability in the effects of explanatory variables is confirmed using two series of likelihood ratio tests based on the two alternate models. A wide variety of variables is observed to determine pedestrian-injury severities. The estimation results show significant non-transferability across the three grades in both RPML and LCML models. In addition, several explanatory variables produce relatively transferable effects, which can provide some valuable insights to implement effective countermeasures. Moreover, out-of-sample predictions are simulated to confirm the non-transferability, while the LC models produce higher differences for the non-transferability than RP models. According to estimation results, several practical measurements concerning education programs, traffic enforcement, emergency response systems, and traffic safety measurements are implemented to eliminate tunnel crash outcomes. Understanding and depth comparing the estimation results, likelihood ratio tests and out-of-sample predictions using alternate models is a promising direction for future research to explore how the observed and unobserved heterogeneity can be estimated. [ABSTRACT FROM AUTHOR]

Distraction and overspeed behaviors are acknowledged as two significant contributors to single-vehicle motorcycle crashes, injuries and fatalities resulting from which are severe and critical issues in Pakistan. To explore the temporal instability and differences in the factors determining the injury severities between single-vehicle motorcycle crashes caused by distraction and overspeed behaviors, this study estimated two groups of random parameter logit models with heterogeneity in means and variances. Single-vehicle motorcycle crash data in Rawalpindi city between 2017 and 2019 was used for model estimation, and a wide variety of explanatory variables relating to the rider, roadways, environments, and temporal attributes was simulated in the models. The current study considered three possible crash injury severity outcomes: minor injury, severe injury and fatal injury. Likelihood ratio tests were conducted to explore the temporal instability and non-transferability. Marginal effects were also calculated to further reveal temporal instability of the variables. Except for several variables, the most significant factors reported temporal instability and non-transferability, manifested as the effects varied from year to year and across different crashes. Moreover, out-of-sample prediction was also implemented to capture temporal instability and non-transferability between distraction and overspeed crash observations. The non-transferability between motorcycle crashes caused by distraction and overspeed behaviors provides insights into developing differentiated countermeasures and policies targeted at preventing and mitigating single-vehicle motorcycle crashes caused by the two risk-taking behaviors. [ABSTRACT FROM AUTHOR]

Abstract In this study, the corrosion behavior of X80 pipeline steel in the presence of Brevibacterium halotolerans (B. halotolerans) was investigated by surface analysis and electrochemical measurements. Results show that B. halotolerans can attach to the surface of X80 steel, and the entire surface is covered with B. halotolerans. The corrosion products induced by B. halotolerans were FeOOH, Fe 2 O 3 and FeSO 4. X80 steel corrosion was accelerated in the presence of B. halotolerans and was susceptible to pitting corrosion. The formation of pitting corrosion could be due that the B. halotolerans oxidization of elemental iron in X80 steel to either obtain electrons from the reduction of nitrate in the underlying biofilm or in the damaged corrosion product film. Highlights • B. halotolerans behaves a kind of NRB in soil corrosion MIC. • B. halotolerans can restore NO 3 − into NH 4 +. • B. halotolerans promotes pitting corrosion of X80 steel in soil environment. [ABSTRACT FROM AUTHOR]

The total arsenic (As) and As species were analyzed in 19 species of wild marine organisms collected from 12 locations in Daya Bay, China; additionally, both the levels of As in the seawater and sediments and the salinity were investigated. The greatest level of As was found in crabs (13.4–35.1 μg/g), followed by shrimps (8.52–27.6 μg/g), benthic fish (3.45–28.6 μg/g), and pelagic fish (1.22–5.23 μg/g). There were significantly positive correlations between the As concentrations in the benthic fish Callionymus richardsonii /shrimp Metapenaeopsis palmensis and those in sediments, indicating that As levels in them were highly dependent on those in the sediments. Arsenobetaine (AsB) (87.3–99.8%) was the most dominant form of As found in all marine organisms. In benthic fish and shrimp, the bioaccumulation of As, especially AsB, was positively correlated with the salinity of the seawater, indicating that the salinity could control the transfer of As. The calculated hazard quotients (HQs) of the inorganic As in the marine organisms were all <1; thus, there was no apparent health hazard through the consumption of wild marine organisms. [ABSTRACT FROM AUTHOR]

Stress corrosion cracking (SCC) of a forged Mg-Al-Zn magnesium alloy with different surface conditions was studied by the four-point bending test and alternate immersion test in NaCl solution. The results showed that the bare Mg-Al-Zn magnesium alloy has low susceptivity to SCC, and no abrupt rupture happened after the immersion test for 5 days under an initial stress load of 0.15–0.75σ0.2. With microarc oxidation (MAO) coating, corrosion resistance was enhanced, but more surface cracks were induced, and microcracks could be detected inside corrosive pits when the load was 0.75σ0.2, which is similar to the bare alloy. The composite coating totally avoided both SCC and corrosion. The low susceptivity of the forged AQ80M alloy to SCC should be attributed to the fine grain size and even distribution of secondary phases around the grain boundary. [ABSTRACT FROM AUTHOR]

A chitosan-based flame retardant with a caged structure, chitosan maleic acid mono (1-thio-phosa-4-hydroxymethyl-2,6,7-trioxa-bicyclic [2.2.2] octan-4-methylene) ester salt (CS-MA-SPEPA), was synthesized and characterized. Cone calorimeter (CC) results indicated that the introduction of CS-MA-SPEPA into an unsaturated polyester resin (UPR) matrix could effectively reduce the HRR, TRR, and SPR. More importantly, the incorporation of CS-MA-SPEPA suppressed the release of toxic gases (CO) from the UPR matrix. The char residues results implied that the combination of CS-MA-SPEPA into UPR increased the degree of graphitization of the matrix and made char residues intumescent and tight, which could efficiently block the exchange of oxygen and heat. [ABSTRACT FROM AUTHOR]

Polycrystalline diamond compact bit directional drilling technology has proven to be an important means to effectively improve drilling efficiency and save drilling costs. Under the directional drilling condition of PDC bit, due to the existence of screw angle or offset mechanism, the center axis of the bit deviates from the center of the borehole, and the cutting teeth of the bit do complex alternating trajectory cutting motion at the bottomhole and the trajectory lines of the cutting teeth themselves intersect in space. (1) The kinematics analysis of directional drilling PDC bit under different working conditions was carried out, including motion analysis at the stage of sliding steering deflection and motion analysis at the stage of composite steering drilling. The kinematics equation of PDC bit under sliding steering deflection and motion space equation of PDC bit cutters at the stage of composite steering drilling were deduced respectively. (2) By establishing the calculation model of cross Angle of cutters under directional drilling conditions, the influences of transmission ratio, tooth placement, offset and deflection Angle on the cross angle are analyzed. The movement law of PDC cutters and the bottom hole morphology formed by bit are studied under directional drilling conditions. (3) Based on the digital simulation system of PDC bit rock breaking, the cutting load under the state of alternating trajectory was studied. On this basis, the cutting mechanics model of PDC bit cutters in directional drilling was established. At the same time, the accuracy of simulation analysis was verified by laboratory unit experiments. It is considered that PDC cutters can form alternate cutting path in directional drilling, which can easily invade rock and improve mechanical efficiency. The larger the intersecting angle of the cutting teeth, the more likely the rock is to form a through crack and then be broken. When the intersecting angle is 90°, the average energy consumption of rock breaking in cross cutting is reduced by about 32.9% compared with parallel cutting. The research results have improved the understanding of the rock breaking mechanism of PDC bit directional drilling, provided a new technical means for bit performance analysis and have also provided a reference for the design of new personalized bits under the discussed working conditions. • The establishment of the function model of the intersection angle between the current circle motion trajectory of each cutting tooth of the PDC drill bit and the motion trajectory of the front and back two circles in the time step. According to the principle of mechanics and using the vector method, the calculation formula of the cutting tooth trajectory crossing angle in different steering systems under the condition of PDC bit directional drilling was deduced, and the corresponding mathematical model was established. The most important performance of the movement path of PDC bit cutters is the change of the cross Angle between the current movement path and the front and back movement paths of each cutter in the time step. The cross angle produced by the variable has an important influence on the crushing specific work and the main cutting force. • The cutting tooth motion trajectory is studied under different parameters. Analyze the influence of the four factors of PDC bit in the directional drilling conditions of speed ratio, positioning radius, deflection angle and offset on the single-tooth motion trajectory and the impact on the bottom hole coverage of the cutting tooth motion trajectory. The survey found that in previous studies, the difference in the intersection angle formed by the single-tooth cutting motion trajectory under different factors was not studied, and the influence of different factors on the bottom hole coverage of the cutting tooth motion trajectory was also not studied. The following conclusions are drawn: as the speed ratio increases, the corresponding cutting tooth movement track is longer. When the rotation ratio is a non-integer, the problem of the track line being fixed in the same area can be avoided, so the speed ratio is set to a larger value or A non-integer value is appropriate; with the increase of the positioning radius, the change range of the cross angle of the cutting tooth motion trajectory is significantly reduced. The core teeth of the inner cone of the positioning radius are prone to directional "rotation", while the other areas of the drill bit The cutting teeth will not have this kind of phenomenon. Therefore, when designing the PDC drill bit layout, attention should be paid to the problem of the reverse force on the heart teeth; as the bit offset continues to increase, the cutting teeth are between the front and rear trajectories The crossing angle of the tooth is obviously increased; with the increase of the deflection angle, the radial fluctuation area and the axial fluctuation range of its trajectory increase, and the movement cutting trajectory formed by each tooth is longer, which is more conducive to the realization of cutting The full coverage of the trajectory of the teeth at the bottom of the well improves the rock breaking efficiency of the drill bit. • The change of the intersection angle between the current circle motion trajectory and the motion trajectory of the two circles before and after each cutting tooth of the PDC drill bit in a time step, and the effect of the resulting cross angle variable on the crushing power and main cutting force. When other parameters remain unchanged, compared with parallel cutting, with the increase of the cross angle (maximum 90°), the axial main cutting force and crushing work of the cutting teeth in the cross cutting mode show a gradient decline and are both lower than Main cutting force and crushing specific work in parallel cutting mode. When the cross angle is 90°, the main cutting force and crushing specific work of the cutting teeth in the cross cutting state reach the lowest value. Therefore, when the drill bit is working, forming a rock breaking method with a cross angle is more labor-saving than parallel cutting, and the greater the cross angle (maximum 90°), the more labor-saving. Therefore, the PDC bit design should ensure that the cutting teeth can form a cross at the bottom of the hole The cutting feature facilitates cross-cutting of the rugged ridge topography formed at the bottom of the well, making it easier for the PDC bit to improve the efficiency of rock breaking and save drilling costs. [ABSTRACT FROM AUTHOR]

• Construct a deep learning network to estimate intercity heavy truck mobility flows. • Reveal the factors contributing to intercity heavy truck movements. • Uncover the heterogeneity of influencing factors across city pairs. • Discover the synergistic and antagonistic effects related to space. Accurate estimation of intercity heavy truck mobility flows is of vital importance to urban planning, transportation management and logistics operations. The inaccessibility of big data related to intercity transport systems and the heterogeneity of trucking activities pose challenges for the reliable estimation. Recently, the advance of Artificial Intelligence (AI) provides a potential solution to this problem. However, most previous studies focused on the estimation of inter-regional passenger mobility. In-depth studies of estimating intercity heavy truck mobility flows by using deep learning techniques are still scarce. To fill in the gaps, we construct a deep neural network based on the Deep Gravity framework, an advanced predictive model for human mobility. We collect a wide range of data related to heavy truck movements, freight locations, road networks and land uses to train the model, and validate its high performance by comparing to traditional gravity model. Furthermore, we use an explainable AI technique to interpret how the city features contribute to the determination of intercity heavy truck movements, and the results can provide valuable policy implications for logistics operations, businesses and urban planning. [ABSTRACT FROM AUTHOR]

• Construct urban heavy truck mobility networks by using massive movement flows. • Uncover the hierarchical organization of urban heavy truck flows. • Discover the industry-specific location concentration and individual location roles. • Develop a novel community-based spatial network growth model. Knowledge of the hierarchical organization of urban heavy truck flows is important for understanding the structure of urban freight system and underlying interactions dynamics, providing insights to assess and develop freight policies. The complexity and dynamic nature of urban freight system pose significant challenges in comprehensively capturing structured arrangement of heavy truck movements. In this paper, we uncover the hierarchical organization of urban heavy truck flows by using complex network theory. We use large-scale heavy truck GPS data and urban freight location point-of-interest (POI) data to construct urban heavy truck mobility networks, and detect their community structure. The empirical results suggest different sets of locations are closely linked to each other to form multiple clusters. By integrating the categories of locations, we reveal the cluster-specific industry concentration and industry-specific location roles, informing evidence-based policy formulation. To capture the interaction dynamics of locations, we develop a spatial network growth model that considers the spatial agglomeration of industrial clusters and interaction pattern of locations. The model provides a mathematical tool to simulate the formation process of real-world networks for logistics planning and management. [ABSTRACT FROM AUTHOR]

• Three kinds of TWIP with different carbide contents were obtained by aging treatment. • The precipitation phase of carbide is mainly MoC and Cr 3 C 2. • Cr/ Mo carbides and austenite matrix exist potential difference to form local galvanic couple. Fe-Mn-C twinning-induced-plastic (TWIP) steel was prepared by adding Cr and Mo, and the effect of Cr/ Mo carbides on the corrosion behaviour of TWIP steel was studied. Different contents of carbide were obtained by aging treatment. The parameters for heat treatment method were 1150 ℃ and 2 h solid solution treatment, aging at temperature 700 °C, heat preservation for 6 and 24 h. Results show that the carbide precipitation phase occurred preferentially in the grain boundary and partly at the interior of grain when the aging time increased. The carbide precipitation phases were primarily MoC and Cr 3 C 2. Cr/ Mo carbide and austenite matrices exhibited phase potential difference and formed a local galvanic couple. More carbides were precipitated, and more galvanic couples were generated as the aging time increased, which resulted in serious corrosion. [ABSTRACT FROM AUTHOR]