Precision operation technology and intelligent equipment in farmland is centered on farmland cultivation, planting, management, harvesting, and other operations ...
This paper proposes an envelope control framework for four-wheel independently actuated autonomous ground vehicle (AGV) to regulate it on desired path and simultaneously control it to the driving ...limits. The envelope control framework is achieved based on the integrated control of active front-wheel steer and direct yaw-moment control. In a speed controller, the G-G diagram is used to describe the driving limits on each path segment. The desired traction and braking force is calculated according to the G-G diagram and desired path. In a path-following controller, a feedforward-feedback lateral controller is designed to calculate the desired steering angle to follow the desired path. In a yaw-moment controller, the β-r phase portraits are utilized to describe the handling limits. The yaw-moment controller aims at keeping the AGV from losing stability in limit driving, which is calculated through a sliding mode controller and provided by the independent motors actuation. Through an independent driving technique, the tyre cornering stiffness is estimated online based on the predefined Magic Formula model to improve the controller's robustness. An autonomous Formula Student racecar developed by the authors is used as testbed. The autonomous driving experiments on racetrack validate the efficiency of the proposed controller.
Cachexia is a multifactorial disease characterized by weight loss via skeletal muscle and adipose tissue loss, an imbalance in metabolic regulation, and reduced food intake. It is caused by factors ...of catabolism produced by tumors in the systemic circulation as well as physiological factors such as the imbalanced inflammatory activation, proteolysis, autophagy, and lipolysis that may occur with gastric, pancreatic, esophageal, lung cancer, liver, and bowel cancer. Cancer cachexia not only negatively affects the quality of life of patients with cancer but also reduces the effectiveness of anti-cancer chemotherapy and increases its toxicity, leading to increased cancer-related mortality and expenditure of medical resources. Currently, there are no effective medical interventions to completely reverse cachexia and no approved drugs. Adequate nutritional support is the main method of cachexia treatment, while drugs that target the inhibition of catabolism, cell damage, and excessive activation of inflammation are under study. This article reviews recent advances in the diagnosis, staging, and evaluation of cancer cachexia. Keywords: cancer cachexia, disease staging, metabolic dysfunction
•Successfully applied FSW for butt joining Al6061 to TRIP 780/800 steel.•Process parameters effects on Al–Fe interface based on temperature and welding force.•Weld nugget characterization.•Al–Fe ...interface and joint quality.
Thin sheets of aluminum alloy 6061-T6 and one type of Advanced high strength steel, transformation induced plasticity (TRIP) steel have been successfully butt joined using friction stir welding (FSW) technique. The maximum ultimate tensile strength can reach 85% of the base aluminum alloy. Intermetallic compound (IMC) layer of FeAl or Fe3Al with thickness of less than 1μm was formed at the Al–Fe interface in the advancing side, which can actually contribute to the joint strength. Tensile tests and scanning electron microscopy (SEM) results indicate that the weld nugget can be considered as aluminum matrix composite, which is enhanced by dispersed sheared-off steel fragments encompassed by a thin intermetallic layer or simply intermetallic particles. Effects of process parameters on the joint microstructure evolution were analyzed based on mechanical welding force and temperature that have been measured during the welding process.
In recent decades, rising anthropogenic greenhouse gas emissions (mainly CO2 and CH4) have increased alarm due to escalating effects of global warming. The dry carbon dioxide reforming of methane ...(DRM) reaction is a sustainable way to utilize these notorious greenhouse gases. This paper presents a review of recent progress in the development of nickel‐based catalysts for the DRM reaction. The enviable low cost and wide availability of nickel compared with noble metals is the main reason for persistent research efforts in optimizing the synthesis of nickel‐based catalysts. Important catalyst features for the rational design of a coke‐resistant nickel‐based nanocatalyst for the DRM reaction are also discussed. In addition, several innovative developments based on salient features for the stabilization of nickel nanocatalysts through various means (which include functionalization with precursors, synthesis by plasma treatment, stabilization/confinement on mesoporous/microporous/carbon supports, and the formation of metal oxides) are highlighted. The final part of this review covers major issues and proposed improvement strategies pertaining to the rational design of nickel‐based catalysts with high activity and stability for the DRM reaction.
New from old: Salient catalyst features and innovative design strategies for nickel‐based catalysts to achieve high stability and coke resistance for CO2 (dry) reforming of methane is reviewed and developments from recent years are discussed with examples.
Pexidartinib (PLX3397), a colony‐stimulating factor‐1 receptor (CSF1R) inhibitor, is currently in phase 1–3 clinical trials as a treatment for a variety of tumours. CSF1R signalling regulates the ...development, survival and maintenance of microglia, the resident brain innate immune cells. In this study, we examined the effects of PLX3397 in the drinking water of mice on microglia in the hippocampus using ionized calcium‐binding adapter molecule 1 (Iba1, a microglial marker) immunocytochemistry. A high concentration of PLX3397 (1 mg/mL) significantly decreased the density of Iba1‐immunoreactive cells after 7 days of exposure, but a low concentration of PLX3397 (0.5 mg/mL) did not. In addition, both low and high concentrations of PLX3397 significantly increased the intersection number, total length and maximum length of microglial processes in male mice. PLX3397 administered for 21 days eliminated microglia with 78% efficiency in males and 84% efficiency in females. Significant increases in microglial processes were found after both seven and 21 days of PLX3397 exposure in males, whereas decreases in microglial processes were observed after both 14 and 21 days of exposure in females. After PLX3397 withdrawal following its administration for 14 days in males, the soma size quickly returned to normal levels within a week. However, the microglial density, intersection number and total length of microglial processes after 3 days of recovery stabilized to untreated levels. In summary, these findings provide detailed insight into the dynamic changes in microglial number and morphology in the hippocampus in a dose‐ and time‐dependent manner after PLX3397 treatment and withdrawal.
Our data demonstrated the dynamic changes in microglial density, microglial soma area, total length, maximum length, and intersection number of microglial processes in the hippocampus during pexidartinib (PLX3397) administration and withdrawal. In addition, our findings indicate the sexually dimorphic responsiveness of microglial morphology to PLX3397 in male and female mice.
An electrically assisted friction stir welding (FSW) system has been developed, which enables a local electrical current field moving with the FSW tool without requiring the tool to be one of the ...electrodes. The effectiveness of electro-plastic effect, which describes a material softening phenomenon during plastic deformation induced by high density current, was investigated for FSW of dissimilar Al 6061 to TRIP 780 steel. Measured temperature results indicate that the electro-plastic effect could hardly be separated from resistance heating for this process. The relative significance of these two factors depends on welding parameters. Axial welding force can be effectively reduced with application of current and the phenomenon is more pronounced under a lower rotating speed and a smaller tool offset into aluminum. Microstructure analysis has been performed for cross sections perpendicular to weldline both at beginning and middle position of the weld. Enhanced formation of thin layer of intermetallic compounds and micro-interlock features at the Al–Fe interface can be observed in electrically assisted welding conditions, which are believed to be beneficial for joint quality.
Thermal error caused by the thermal deformation is one of the most significant factors influencing the accuracy of the machine tool. Among all the heat sources which lead to the thermal distortions, ...the spindle is the main one. This paper presents an overview of the research about the compensation of the spindle thermal error. Thermal error compensation is considered as a more convenient, effective and cost-efficient way to reduce the thermal error compared with other thermal error control and reduction methods. Based on the analytical calculation, numerical analysis and experimental tests of the spindle thermal error, the thermal error models are established and then applied for implementing the thermal error compensation. Different kinds of methods adopted in testing, modeling and compensating are listed and discussed. In addition, because the thermal key points are vital to the temperature testing, thermal error modeling, and even influence the effectiveness of compensation, various approaches of selecting thermal key points are introduced as well. This paper aims to give a basic introduction of the whole process of the spindle thermal error compensation and presents a summary of methods applied on different topics of it.
•Thermal error compensation is an effective and economical way to reduce the error.•Analyzing, testing, modeling and compensating are main aspects of the research.•Various devices and systems for temperature and thermal error testing are introduced.•Different kinds of methods used for thermal error modeling are studied.•Two commonly used mechanisms of thermal error compensation are explained.
Ru/CeO2 catalysts with different amounts of surface oxygen vacancies were prepared by changing the morphology of CeO2. The conversion of Ce4+ to Ce3+ and the formation of Ru–O–Ce bonds led to ...enhancement of the amount of oxygen vacancies. Ru species of low crystallinity enriched with Ru4+ ions exist on the surface of CeO2 nanorods, while metallic Ru particles exist on CeO2 nanocubes. The low crystallinity of Ru species and high concentration of oxygen vacancies enhanced the adsorption of hydrogen and nitrogen and also led to desorption of surface hydrogen in the form of H2. Therefore, Ru/CeO2 nanorods showed high ammonia synthesis activities. On the contrary, lower catalytic activity was observed over Ru/CeO2 nanocubes catalyst because H2 and N2 adsorption was less favorable plausibly due to the large particle size of Ru species and low concentration of oxygen vacancies, and most of the hydrogen species were consumed in H2O formation.
This study investigates and compares mechanical factor (a dimensionless parameter and defined as the ratio of the compressive strength of fiber reinforced soil to that of unreinforced soil) for soils ...reinforced with four different fibers (three natural fibers and one synthetic fiber). An integrated methodology was utilized, including 351 laboratory experiments for obtaining data and Extreme Learning Machine (ELM) technique for developing functional relationships between mechanical factor and soil and fiber parameters. Soils reinforced with synthetic fiber (Polypropylene) and with natural fibers exhibited different characteristics when subjected to the same variation in soil parameters. This phenomenon can be attributed to the differences in surface morphology and water absorption capability of Polypropylene comparative to other natural fibers. Polypropylene-soil composite shows the maximum sensitivity to the soil moisture. It also shows the least sensitivity toward soil density and fiber content among all tested fiber-soil composites.
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