Search

Transition-metal phosphides have been investigated for microwave absorption applications owing to their excellent conduction loss and magnetic property. In this study, novel composites comprised of porous Al 2 O 3 matrix loaded with Fe x Co y P (Fe x Co y P/Al 2 O 3) were prepared by vacuum impregnation, hydrothermal, and low-temperature phosphatizing methods. The experimental results show that Fe x Co y P is uniformly deposited on the surface of porous Al 2 O 3 ceramic, and the Fe x Co y P transforms from needle-like to particle-like structures as the Fe/Co ratio increases from 1:3 to 3:1. The minimum reflection loss (RL min) of FeCo 3 P/Al 2 O 3 composite reaches −26.19 dB at 12.4 GHz with a matching thickness of 2.6 mm, and the maximum effective absorption bandwidth (EAB) achieves 4.2 GHz in the whole X-band at 3.2 mm thicknesses. This study confirmed that the porous Fe x Co y P/Al 2 O 3 composites are potential candidates for microwave absorption applications, and their microwave absorption properties can be enhanced by adjusting the ratio of Fe to Co. [ABSTRACT FROM AUTHOR]

Hydrogen technology is widely considered a novel clean energy source, and electrolysis is an effective method for hydrogen evolution. Therefore, efficient hydrogen evolution reaction (HER) catalysts are urgently needed to replace precious metal catalysts and meet ecological and environmental protection standards. Herein, Ni–Mn–P electrocatalysts are synthesized using facile electrodeposition technology. The influence of the Mn addition on the catalytic behavior is studied by the comprehensive analysis of catalytic performance and morphology of the catalysts. Among them, the Ni–Mn–P0.01 catalyst exhibits small coral-like structures, greatly improving the adsorption and desorption of hydrogen ions and reducing the overpotential hydrogen evolution. Consequently, overpotential at 10 mA cm−2 electric current density is 113 mV, and the value of the Tafel slope achieves 74 mV/dec. Furthermore, the Ni–Mn–P catalyst shows long-time (20 h) stability at current densities of 10 and 60 mA/cm2. The results confirm that the synergistic effect of Ni, Mn, and P accelerates the electrochemical reaction. Meanwhile, the addition of manganese element can change the micromorphology of the catalyst, thereby exposing more active sites to participate in the reaction, enhancing water ionization, improving the catalytic performance. This study opens a new way toward improving the activity of the catalyst by adjusting Mn concentration during the electrodeposition process. [Display omitted] • Ni–Mn–P electrocatalysts are synthesized by facile electrodeposition technology. • 3D spherical microstructure Ni–Mn–P catalyst can be formed. • 3D spherical microstructure improves the adsorption and desorption of hydrogen ions. • Ni–Mn–P catalyst improves the hydrogen evolution reaction and longtime stability. [ABSTRACT FROM AUTHOR]

In order to predict the long-term creep life of P91 steel, this work proposed a coupled model, combining the error-trained back-propagation artificial neural network (BP-ANN) and an improved θ model. Both the short-term rupture life obtained by creep experiments and the related creep data of National Institute for Materials Science (NIMS) database were used to validate the above model. In this model, creep parameters (temperature, stress) were used as the input and relative error of 5 θ model extrapolations as the output. Then, the prediction errors of BP-ANN method were introduced to correct the 5 θ model extrapolation results to achieve a more accurate prediction. Consequently, the long-term creep life of P91 steel was predicted. It demonstrated that with the proposed model, the prediction capability for long-term creep life of P91 steel with 200,000 h is much better than those of other θ methods, which has a prediction uncertainty less than 5%. • A model coupled the improved 5 θ model with BP-ANN was proposed. • The proposed model based on error-training predicted the long-term creep life of P91 steel successfully. • The prediction accuracy of proposed model was much better than those of the 4 θ and 5 θ models. [ABSTRACT FROM AUTHOR]

Abstract Using the internal friction measurement, this work dealt with the change of dislocation configuration during the creep of 9Cr 1Mo steel at 873 K. At different creep times, specimens of this steel were firstly prepared by the interrupted test to simulate various creep states. Then, the internal friction of these specimens was measured by a dynamic mechanical analyzer (DMA) to characterize the dislocation configuration. Based on the analysis of internal friction results, it showed that both the density and distribution of diffusion-controlled dislocations vary continuously with creep time, and there has a density peak at the end of primary creep. Meanwhile, the kinetics of dislocation motions was introduced to study the evolution of dislocations during present creep in detail. In comparison with the calculated results, the movement mechanism of above diffusion-controlled dislocations was clarified successfully by the modeled dislocations. In addition, the present work offered a powerful tool to evaluate the configuration of dislocations rather than mobile dislocations. Highlights • The diffusion-controlled dislocations during creep of 9Cr-1Mo steel was successfully characterized using internal friction measurement. • It revealed that these diffusion-controlled dislocations are actually the immobile dislocations forming during creep. • The internal friction measurement offers a potential method to characterize the configuration of dislocations rather than mobile dislocations. [ABSTRACT FROM AUTHOR]

Integrins (ITGs) are transmembrane heterodimer receptors with ITGα subunit and ITGβ subunit, participating in various physiological processes, including immunity. At present, systematic research on ITGs in teleost is scarce, especially in half-smooth tongue sole (Cynoglossus semilaevis). In this study, a set of 28 ITG genes in half-smooth tongue sole have been identified and characterized. The phylogenetic analysis showed that ITGα and ITGβ subunits were respectively classified into five and two clusters, consistent with previous studies. The selection pressure analysis indicated that most of ITG genes were under purifying selection, except for ITGα11b and ITGαL with positive selection. The expression profiles of eight selected ITG genes, including ITGα1 , ITGα5 , ITGα8 , ITGα11 , ITGβ1 , ITGβ2 , ITGβ3 , and ITGβ8 , were analyzed in healthy tissues and after infection with Vibrio anguillarum , revealed their implications in immune response. The study provided a comprehensive characterization and expression analysis of ITG genes in half-smooth tongue sole, setting a solid foundation for further functional studies and promising potential in disease control. [Display omitted] • A total of 28 integrin genes of half-smooth tongue sole were identified and characterized. • Integrins were widely expressed in various tissues, with distinct levels. • Integrins were differentially expressed after infection with Vibrio anguillarum. [ABSTRACT FROM AUTHOR]

In this paper, we study a single machine scheduling problem by simultaneously considering the processing method of serial-batching, learning effect, resource-dependent processing times, and setup operations. We consider minimizing the makespan as the objective of the studied problem under the constraint that the total resource consumption does not exceed a given limit. For the special case where the resource allocation is given, we first propose the structural properties for job batching policies and batching sequencing, and an optimal batching policy is derived based on these properties. Then, we develop a novel hybrid GSA–TS algorithm which combines the Gravitational Search Algorithm (GSA) and the Tabu Search (TS) algorithm to solve the general case. Computational experiments with different scales show the effectiveness and efficiency of the proposed algorithm. [ABSTRACT FROM AUTHOR]

In this study, the change of geometrically necessary dislocation (GND) has been investigated during the elevated temperature creep of P91 steel. Firstly, the crept microstructures of P91 steel at 873 K and 165 MPa were characterized by electron backscatter diffraction (EBSD). Then, the resultant GND distributions were analyzed in detail. Meanwhile, the GND density was quantitatively estimated by two methods of kernel average misorientation (KAM) and Nye's dislocation density tensor, respectively. The obtained results indicated that during creep of P91 steel, the values of GND density calculated by the KAM method are highly consistent with those of Nye's dislocation density tensor method. Besides, the GND density increases significantly during the initial creep stage and attains the maximum approximately at the transition from initial creep to steady creep. During the subsequent creep, it gradually decreases. In addition, it suggested that the internal stress predicted by the obtained GND density is consistent with previous experimental data. Accordingly, it further demonstrated that the present characterization of GND evolution offers a convenient tool for the microstructure degradation analysis of P91 steel during creep. • The microstructure of P91 steel during creep has been investigated by EBSD method. • The change of GND density was quantitatively characterized by KAM and Ney's dislocation density tensor, respectively. • The GND densities obtained by the above methods are highly consistent. • The GND densities vary closely with the creep stage, resulting from the interaction between dislocation and precipitates. [ABSTRACT FROM AUTHOR]

The reliable prediction of long-term creep life is of great importance in order to ensure the service safety of high-temperature components. In this work, the novel Wilshire-Cano-Stewart (WCS) relationships were introduced to model the creep behavior and predict the long-term creep life of P91 steel based on the short-term creep data. The accelerated creep experiments were firstly carried out at the temperature range of 580–620 °C, while the stresses varied from 135 to 200 MPa. According to the analyses of normalized-mean-squared error (NMSE) and mean logarithmic error (MLE), it demonstrated that the WCS model can express all the obtained creep data very well due to the average relative errors lower than 10%. Meanwhile, these values are much lower than those of traditional Time-Temperature-Parameter (TTP) models. In addition, the WCS model can provide the reasonable estimates of 200,000 h creep life with accelerated creep measurements lasting up to only 2000 h. • WCS model made full use of Wilshire and Sinh model respective advantages and eliminated known weaknesses. • Results of WCS model are better than the traditional L-M model in life prediction. • Results of WCS model are accurate enough in life prediction. [ABSTRACT FROM AUTHOR]

Green tide outbreaks caused by overgrowth of Ulva prolifera in the Yellow Sea of China can cause serious ecological stress with concomitant economic hardships, especially to marine fisheries. In this study, short-term effects (14 days) were evaluated using fresh algae U. prolifera (FU), and a 7-day assessment of the effects of decomposing U. prolifera (DU) algal effluent was conducted to determine the effects on the environmental and intestinal microbiota, intestinal transcriptome and mortality of the commercial marine benthic fish, Japanese flounder (Paralichthys olivaceus). The results revealed that algal degradation altered the microbial community structure of fish farm water and fish intestines and increased the relative abundance of the pathogens Flavobacteriaceae in water and Vibrio in fish intestines. Fish intestinal tissue structure appeared to be damaged, as indicated in pathological sections, and transcriptome analysis showed intestinal inflammation after exposure, which may have caused an increase in fish mortality. The degradation of U. prolifera led to a bloom of potential pathogenic bacteria and the inflammation of fish intestines, which resulted in disease in the flounder population that reduced fish harvests and might pose a potential health threat. [Display omitted] • U. prolifera decomposition affected the microbiota in the water and fish intestines. • Potential pathogens Flavobacteriaceae in water significantly increased. • The conditional pathogen Vibrio increased significantly in the intestine of Japanese flounder. • U. prolifera exposure damaged fish intestinal structure and increased mortality. • DEGs related to immunity and inflammation in the intestine changed significantly. [ABSTRACT FROM AUTHOR]

Using the nonlinear Lamb wave, this work investigated the damage resulting from microstructure evolution during the creep of 9Cr 1Mo steel at 873 K in detail. At eight creep times, specimens of this steel were firstly prepared by the interrupted test to simulate various creep states, respectively. Then, the measurement of acoustic nonlinearity parameter, and microstructure observation were employed to characterize the resultant damage. The experiment results showed that the measured value of this parameter is strongly dependent upon the creep state. Meanwhile, the hierarchical microstructure of 9Cr 1Mo steel evolves during creep. In order to conduct the quantitative assessment, both the analytical model of acoustic nonlinearity, and the kinetics of microstructure evolution were applied to calculating the acoustic nonlinearity parameter during creep. By comparison of the measured and calculated results, the predominated component of acoustic nonlinearity during the present creep of 9Cr 1Mo steel was clarified successfully by the modeled microstructures. Above all, the present work provided an effective way to monitor and evaluate the creep damage quantitatively. • Acoustic nonlinearity parameter of eight crept specimens with different states was measured using the nonlinear Lamb wave. • A quantitative model was provided to predict quite similar variations of the measured acoustics nonlinearity parameters. • The change of acoustic nonlinearity during the whole creep is determined by the configuration of substructure boundary. [ABSTRACT FROM AUTHOR]

The analysis of aircraft fuel consumption remains an important topic as fuel consumption constitutes a large portion of airline operational costs, and exhaust emissions generated by aircraft gradually have become an essential aspect of urban air pollution, especially during takeoff and descent. Previous studies have focused mainly on optimizing fuel loss and greenhouse gases emission via three key methods: reducing additional aircraft load, using inventive air transfer control methods, and identifying the best-performing aviation systems for all conditions. However, there are few studies that have considered the relationships among fuel consumption, pilot behavior, and flight factors. This study fills this gap by focusing on the relationships between fuel consumption and three factors during the descent phase: altitude, weight, and speed. Further, we propose an improved K-means clustering algorithm to analyze the flight data, conducting clustering analysis on multi-dimensional data based on real flight records of Boeing 737s operated by China Eastern Airlines. We conclude the highlights of this study into three aspects: (1) the relationship between aircraft descent and fuel consumption is investigated through clustering analysis to find a fuel-efficient aircraft descent. (2) an improved K-means clustering algorithm is proposed to analyze flight data. (3) the better aircraft descent is the suggestion for pilots by analyzing the clustering results, which is a good supplement to the Flight Crew Operating Manual (FCOM). In the case study, the improved K-means algorithm is used for the cluster analysis of data from the quick access recorders of two aircraft descending into Chengdu Shuangliu Airport (CTU) in China. Compared with the method that does not use the analysis results for the descending, the average fuel consumption per unit of time decreases by 17.5% when we use our proposed method. In the Shanghai Pudong Airport (PVG), our proposed method reduces average fuel consumption per unit of time by 19.3%. [ABSTRACT FROM AUTHOR]

This paper investigates an order acceptance and scheduling problem with an energy consumption budget, a machine launch budget, and the order release time in a green manufacturing system. The phenomenon of deteriorating jobs is considered in the production of the accepted orders. The objective of the study is to maximize the net revenue and a modified variable neighborhood search (MVNS) Algorithm that combines a novel encoding and decoding procedure as well as a dynamic programming algorithm is developed to solve it. To show the effectiveness and efficiency of the proposed algorithm, we first employ the MVNS algorithm and seven VNS-based algorithms to solve the problems with different configurations of orders and machines. The results show that the MVNS algorithm obtains better solutions than existing VNS-based algorithms. Then, the proposed algorithm is compared with three meta-heuristic algorithms. The experimental results show that the proposed algorithm has significant advantages in terms of solution optimality. [ABSTRACT FROM AUTHOR]

Grazing exclusion has been proposed as an effective practice to enhance ecosystem carbon stocks in arid-semiarid degraded grasslands. However, in humid regions, the effects of grazing exclusion on ecosystem carbon stocks and their components in degraded grasslands remain largely unknown. Here, the effects of enclosure on ecosystem carbon stocks and their components were explored using four enclosure ages, each paired with adjacent grazed areas. Moreover, the results were synthesized with previous studies to test if enclosure's effects in semihumid-humid regions differed from those in arid-semiarid regions. The field experiment found that six months to 1 year of grazing exclusion sequestrated 14.6 % higher carbon in the enclosed grasslands than in paired-grazed grasslands as a consequence of increased carbon storage of plants and topsoils. However, compared to grazed areas, enclosures over 3–6 years contained 14.4 % less ecosystem carbon stocks, primarily due to markedly decreased soil carbon sequestration, despite increased plant carbon stocks. Structural equation models further suggested that the decrease in soil carbon stock might be owing to the decomposition of organic matter induced by low phosphorus. Additionally, compared with the northern slope of the mountain, ecosystem carbon stocks on the southern slope showed a lagged and weak response to grazing exclusion. The results, combined with a meta-analysis, revealed that plant and soil carbon stocks in semihumid-humid grasslands were more sensitive to enclosure than in arid-semiarid grasslands. These results highlight that short-term fencing (e.g., six months to 1 year), rather than long-term, is a practical strategy to foster degraded grassland ecosystem carbon sequestration in semihumid-humid regions, thus contributing to climate change mitigation. • Six months to 1 year of grazing exclusion promoted ecosystem carbon stocks • 3–6 years' fencing reduced ecosystem carbon stocks as the decrease in soil stock • The decrease in soil carbon stock was mainly owing to the imbalance of soil nutrients • Northern slope' carbon stock responded strongly compared to southern slope • Carbon stocks in humid grasslands was more sensitive than in arid grasslands [ABSTRACT FROM AUTHOR]