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A micro-tiller vibrates severely during the rotary tillage process, which may cause operators to develop white finger disease. However, for most vibration models, the acting force between the soil and the rotary cutter roll was simplified to only a constant or sine curve, which may not describe the whole dynamic. Rotary tillage processes have been simulated based on the smoothed particle hydrodynamics method in this paper. The acting forces of the soil on the cutter roll have been obtained with the simulation model. Four different working conditions were simulated. The average error between the calculated forces and the simulated mean forces is 10.96%, which proves the SPH model. By introducing simulated acting forces into the vibration model, a new vibration model of the micro-tiller, which includes the soil–blade interaction, has been constructed. Time and frequency characteristics were simulated with the new vibration model. The errors between the simulated and tested RMS values are 4.28%, 5.03%, and 6.35% for the engine, cutter roll, and right handle, respectively. Two domain-dominant frequencies were found with the vibration model, namely 44.7 Hz and 257.0 Hz. It is helpful to reveal the whole dynamic map of micro-tillers. [ABSTRACT FROM AUTHOR]

Hydrogen is regarded as one of the most promising energy sources of the future, due to its low-cost, zero-pollution, and high-heat value. Nevertheless, traditional methods of storing hydrogen are commonly accompanied by the risk of leaks and explosions, so how to store and transport hydrogen safely and efficiently is a critical issue that needs to be addressed. Solid-state hydrogen storage is the most attractive way to store hydrogen in nanomaterials by chemical or physical adsorption, which has the advantages of high energy density and good safety. Here, a rational Ni–Zn bimetallic MOF has been constructed by a straightforward synthetic technique, in which the Zn atom was partially replaced by the Ni atom. The micropore rate of the Ni–Zn bimetallic MOFs is higher than that of ZIF-8. In addition, the presence of Ni provides more unsaturated metal sites and strengthens the bonding between hydrogen molecules and Ni, effectively improving the hydrogen storage capacity of Ni–Zn bimetallic MOFs. The experimental results show that the hydrogen adsorption capacity of Ni–Zn bimetallic MOFs can reach 1.35 wt% at 77 K and 1 bar. [ABSTRACT FROM AUTHOR]

One of the most promising methods for capturing carbon dioxide (CO2) is solid physical adsorption, which is an efficient and simple technique. The key to effective CO2 capture is the development of high-performance solid adsorbents with excellent CO2 adsorption capacity, CO2/N2 selectivity, and rapid adsorption/desorption kinetics. In this paper, a Mg-MOF-74/sodium alginate composite aerogel was prepared by loading Mg-MOF-74 on sodium alginate sheets followed by directional freeze-drying. The composite aerogel exhibited a hierarchical porous structure, in which sodium alginate provided an open mesoporous/macroporous structure that promoted diffusion and contact with the active center of CO2. The Mg-MOF-74 micropores/mesopores promoted the strong interaction between CO2 and the adsorbent in the micropore and rapid mass transfer of CO2 to the adsorbent through the mesopores. The experimental data showed that MSA-6 achieved CO2 adsorption of 2.461 mmol·g–1 at 298 K. Furthermore, the CO2/N2 adsorption selectivity of MSA-6 reached 35.108, indicating its strong CO2 selective adsorption potential. [ABSTRACT FROM AUTHOR]

Rapid and safe disinfection and exudate management are two major challenges in infected wound care. Therefore, in this work, we developed a novel wound dressing via encapsulating ZIF-8-derived carbon nanoparticles in a hydrophilic nanofiber sponge to address severe wound infection and heavy exudate problems. The dressing can effectively kill bacteria through chemo-photothermal synergistic therapy. Meanwhile, the hydrophilic nanofiber sponge can quickly absorb wound exudate around the wound and accelerate the evaporation rate of liquid through the photothermal effect and its own structure; therefore, it is possible to remove excess liquid and regulate its wetness. In this way, it prevents the problem of wound overhydration often caused by hydrophilic dressings. In our experiment, the dressing showed good antibacterial performance and biocompatibility in vitro and could effectively control wound infection, absorb wound exudate and promote skin wound healing in vivo. Its good therapeutic effect is not only due to effective infection control and wound exudate management, but also because the structure of nanofibers similar to an extracellular matrix provides basic physical support and structural signals conducive to skin tissue regeneration. [ABSTRACT FROM AUTHOR]

Constructing heterostructure in nanomaterials is a scientific and efficient method to optimize the electrochemical properties of supercapacitors. Carbon aerogels (CAs) can enhance electrical conductivity and ion diffusion because of their three-dimensional porous structure, which is useful for fabricating electrodes. The moderate nanoheterostructures in aerogel nanomaterials have made great contributions to the optimization of application performance. Herein, a simple method for constructing the MnO2 nanoparticle/CA (MnO2/CA) heterostructure is proposed. The MnO2/CA heterostructure exhibits outstanding electrochemical capability in a three-electrode system, with a specific capacitance of 384 F/g, higher than 201 F/g of the CA, at a current density of 0.5 A/g. When MnO2/CA is used as a symmetric supercapacitor, it also exhibits a high energy density and power density, with the highest energy density of 33.78 Wh/kg. The prepared MnO2/CA shows improved performance for synergies in providing a high specific capacity and long cycle life. [ABSTRACT FROM AUTHOR]

Navigation line extraction is critical for precision agriculture and automatic navigation. A novel method for extracting navigation lines based on machine vision is proposed herein using a straight line detected based on a high-ridge crop row. Aiming at the low-level automation of machines in field environments of a high-ridge cultivation mode for broad-leaved plants, a navigation line extraction method suitable for multiple periods and with high timeliness is designed. The method comprises four sequentially linked phases: image segmentation, feature point extraction, navigation line calculation, and dynamic segmentation horizontal strip number feedback. The a* component of the CIE-Lab colour space is extracted to preliminarily extract the crop row features. The OTSU algorithm is combined with morphological processing to completely separate the crop rows and backgrounds. The crop row feature points are extracted using an improved isometric segmented vertical projection method. While calculating the navigation lines, an adaptive clustering method is used to cluster the adjacent feature points. A dynamic segmentation point clustering method is used to determine the final clustering feature point sets, and the feature point sets are optimised using lateral distance and point line distance methods. In the optimisation process, a linear regression method based on the Huber loss function is used to fit the optimised feature point set to obtain the crop row centreline, and the navigation line is calculated according to the two crop lines. Finally, before entering the next frame processing process, a feedback mechanism to calculate a number of horizontal strips for the next frame is introduced to improve the ability of the algorithm to adapt to multiple periods. The experimental results show that the proposed method can meet the efficiency requirements for visual navigation. The average time for the image processing of four samples is 38.53 ms. Compared with the least squares method, the proposed method can adapt to a longer growth period of crops. [ABSTRACT FROM AUTHOR]

The cost of CO2 separation and energy consumption can be decreased through the use of CO2 adsorption. Due to the electron-rich heteroatoms in its network, polyimide (PI) has a remarkable affinity for CO2. Polyethylene glycol (PEG) can increase the layer spacing of polymers, so as to change the mass transfer of CO2 in it. Furthermore, the ether bond (-O-) in PEG has good affinity for CO2. In this study, PEG-1000 was introduced into PI aerogel by mild sol-gel method at low temperature, and freeze-drying was used to produce PI/PEG composite aerogels with directional pore structure. The effect of PEG-1000 content and directional pore structure of the PI/PEG composite aerogels on CO2 adsorption performance were further studied. The L-PI/PEG-4 composite aerogel, which contains 4 g PEG and is directionally frozen in liquid nitrogen, has a CO2 adsorption capacity of 16.76 cm3/g at 25°C and 1 bar. L-PI/PEG-4 aerogel also exhibits high CO2/N2 selectivity and adsorption cycle stability. [ABSTRACT FROM AUTHOR]

A vertical variable cavity organic fertilizer and compound fertilizer apparatus were designed according to tobacco farming requirements to overcome issues of unstable fertilizer discharge and blocking in the fertilizer disk of an existing fertilizer apparatus. The structure and working principle of the fertilizer apparatus were described. Combined with the principle of anti-arch and the requirements of fertilizer application, the structure size of the fertilizer apparatus was determined. Using the opening degree and rotational speed of the fertilizer disk as the test factors and the fertilizer rate and variation coefficient of fertilizer application rate as the indices, the EDEM was used to conduct the single factor test and obtain the appropriate rotational speed range. The results indicated that the variation coefficient of the fertilizer uniformity apparatus was 0.96–5.22% under different rotation speeds and fertilizer disk openings, which satisfied design requirements. The orthogonal experiment explored the interaction between rotational speed and the opening. The influence of the opening adjustment on the fertilizer application rate and the coefficient of variation of uniformity were greater than the change in fertilizer disk speed. The bench and field tests aligned with the simulation test. These findings provide a reference and theoretical basis to design a fertilizer apparatus. [ABSTRACT FROM AUTHOR]

High CO2 concentration in atmosphere causes serious environmental issues, and carbon capture and storage technologies have attracted attention as a means to reduce the atmospheric CO2 concentration. Metal-organic frameworks (MOFs) can potentially be used for CO2 adsorption, but their poor stability and microporosity limit their applications. Herein, a novel strategy was proposed to combine a cellulose aerogel and hierarchically-porous MOFs (HP-MOFs) with larger pores. According to this strategy, a series of microcrystalline cellulose/HP-UIO-66-NH2 hybrid aerogels (MC-HUN-X) was constructed by adding a modulator (monocarboxylic acid, MA), followed by the in-situ growth of HP-UIO-66-NH2 on a cellulose aerogel. By adjusting the chain length of MA, the structure–function relationship between pore size and the CO2 adsorption capacity of MC-HUN-X was explored. The results showed that the CO2 adsorption capacity increased first and then decreased upon increasing the MOFs pore size, while the adsorption selectivity of CO2 continuously increased. Among all samples, MC-HUN-4 with a moderate pore size had the highest CO2 adsorption capacity (1.90 mmol/g at 298 K and 1 bar) and adsorption selectivity (13.02 and 2.40 for CO2/N2 and CO2/CH4). The combination with a cellulose aerogel endowed MC-HUN-X with excellent mechanical stability and reusability. Cellulose/HP-UIO-66-NH2 hybrid aerogel with larger aperture sizes of MOF showed excellent adsorption capacity and selectivity for CO2, and the combination with aerogel could effectively improve the mechanical stability and reusability. [ABSTRACT FROM AUTHOR]

The interactions between organelles can maintain normal cell activity. Lysosomes, as waste disposal systems of cells, have many important interactions with the plasma membrane, especially in the repair of cracked plasma membrane. Unfortunately, a way to study the relationship between them synchronously is still lacking. Therefore, in this work, we constructed a dual-targeting probe (Mem-Lyso) to simultaneously visualize the plasma membrane and lysosomes for the first time. Taking advantage of dual-targeting, the probe Mem-Lyso could successfully track and analyze the dynamic changes of the plasma membrane and lysosomes in different bioprocesses. The experimental results demonstrated that, compared to the normal status, there was obvious fusion between the plasma membrane and lysosomes in the apoptosis process. Furthermore, because of the sensitivity to polarity, Mem-Lyso could label the plasma membrane and lysosomes with red and yellow colors in cells, respectively. Moreover, the skeleton and gastrointestinal wall of zebrafish were visualized by dual-color imaging, respectively. More importantly, the dual-targeting property endowed Mem-Lyso with the ability to spatially distinguish the cholesterol (CL) content in the plasma membrane, which provided a potential detection tool for biological research and diagnosis of related diseases. [ABSTRACT FROM AUTHOR]

Developing highly efficient and stable photocatalysts is an effective method to achieve CO2 photocatalytic reduction. Herein, PI/WO3 aerogel photocatalyst was prepared by chemical amide reaction coupled with an ethanol supercritical drying technique. The novel aerogel photocatalysts exhibit excellent photocatalytic performance for reducing CO2 into CO. In particular, PI/WO3-10 aerogel photocatalyst shows the highest yield of CO (5.72 μmol g–1 h–1), which is ca 11-fold higher than that of the pristine PI aerogel. The high CO2 reduction activity can be attributed to the Z-scheme structure, which enhances the separation of photo-generated electron – holes, and induces H2O oxidation on WO3 nanosheets and CO2 reduction on PI aerogel. The photocatalytic reaction mechanism of CO2 when using PI/WO3 aerogel photocatalyst is proposed. [ABSTRACT FROM AUTHOR]

In view of the problems of low stiffness, small driving force and large balloon effect existing in the current soft actuator, this paper proposes an optimization method to enhance the overall stiffness of the soft gripper by using rigid components based on the multi-cavity soft pneumatic actuator. This paper introduces the main components of the actuator: the soft part poured by liquid silica gel, and the open rectangular rigid structures by 3D printed. The kinematics model of the finger is established based on the Piecewise Constant Curvature model(PCC). The bending performance of the enhanced stiffness gripper is verified by finite element analysis(FEA): the tip force of actuator increased with the increase of the number of rigid structures when the bending angle is constant. According to the and experimental data, the overall stiffness of soft gripper is increased by the rigid structure without affecting the flexibility of operation. And the maximum weight which can grasp is 3.4 times that of the traditional soft gripper, improved the grasping range of the soft gripper effectively. [ABSTRACT FROM AUTHOR]

The effects of oxygen partial pressure on the microstructure, electrical and photo-sensitive properties of the Sn-doped In2O3 (ITO) films deposited by different Ar–O2 flow rates (10:0.4, 10:1, 10:1.8 and 10:3) were investigated systematically by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Hall effect, UV-Vis and optical measurements. The XRD and SEM measurements show that the ITO film deposited at oxygen flow rate of 0.4 sccm prefers to (400) orientation and has a rough sawtooth-shaped surface. However, the ITO films deposited at oxygen flow rates of 1 sccm, 1.8 sccm and 3 sccm prefer to (222) orientation and exhibit a flat smooth surface. The conductivity, mobility and photosensitive property of ITO films are also sensitive to oxygen flow rate. The ITO film deposited at oxygen flow rate of 0.4 sccm has a high carrier concentration (up to 1. 2 9 × 1 0 2 1 cm − 3 ) and mobility (16.7 cm2/vs), low resistivity (2. 8 8 3 × 1 0 − 4 Ω ⋅ cm) , and a long response time but good sensitivity to ultraviolet light. It can be concluded that the surface morphology plays a dominant role in sensitivity to ultraviolet light. The good sensitivity of ultraviolet light is gained from the ITO film with sawtooth-shaped surface. [ABSTRACT FROM AUTHOR]

The interstand tension coupling effect and strip gauge variation passed on to next stand with time delay are the main causes for regenerative chatter in tandem rolling mills. To study the effect of different factors on the stability of tandem rolling mills, different models considering different interstand factors were built. Through stability analysis of these models by employing the Lyapunov indirect method and integral criterion, more detailed and quantitative explanation is put forward to regenerative chatter mechanism in rolling. To study the time delay effect as a single factor on the stability of tandem rolling mills, stability charts of the chatter model including the time delay effect and model neglecting the delay time were compared. The results show that the time delay effect reduces the critical velocity of multistand mills slightly in the big picture. But it alters the relationship between two adjacent stands by worsening the downstream stand stability. To get preferable rolling process parameter configuration for the tandem rolling mills, the time delay effect in rolling must be involved. [ABSTRACT FROM AUTHOR]

Low-cost urea formaldehyde resin (UF)/reactive halloysite nanotubes (HNTs) nanocomposite adhesive was prepared successfully via in situ polymerization. The HNTs were modified to improve its compatibility with polymer. The XRD and FTIR results showed that physical and chemical interaction between the HNTs and polymer resin influenced the structure of UF owing to the functional groups on the HNTs. It is found from SEM images that the modified HNTs could be dispersed uniformly in the resin and the nanocomposite particles were spherical. The performance experiment confirmed that thermal stability of nanocomposite increased largely, formaldehyde emission of UF wood adhesive reduced 62%, and water resistance of UF wood adhesive improved by 84%. Meanwhile, the content of HNTs on the nanocomposites could be up to 60 wt %. The mechanism of the nanocomposites based on the reactive HNTs was proposed. The approach of the preparation could supply an idea to prepare other polymer/clay nanocomposites. [ABSTRACT FROM AUTHOR]

A novel power and freshwater generation system is presented based on the gas turbine cycle as the main system and Kalina cycle and humidification-dehumidification desalination unit as the waste heat recovery subsystems. To evaluate the system's performance, energy, exergy, economic, and environmental analysis is performed. The optimum performance of all optimization scenarios is found by applying the multi-objective genetic algorithm and using the technique for order of preference by similarity to ideal solution (TOPSIS) method. The sensitivity analysis is also performed to assess the effect of various parameters on the system's performance. By using Net present value, the feasibility of the plant for the construction from the economic viewpoint is analyzed. Based on the base case results, the performance metrics are evaluated as the energy efficiency of 0.9398 , exergy efficiency of 43.11 % , sum unit cost of 19.44 $. GJ − 1 , Levelized total emission of 63571 kg. kW − 1 , and freshwater production rate of 10.39 kg. s − 1 . Among all system components, the combustion chamber is contributed to the highest rate of exergy destruction rate by 16544 kJ. s − 1 . For fuel cost of 3 $. GJ − 1 and electricity price of 0.09 $. kWh − 1 , the total net present value for the plant lifetime is obtained 1.736 × 10 7 $ , which means that the plant is feasible for construction from the economic perspective. Based on the optimization results, the maximum value of exergy efficiency and minimum value of Levelized total emission are obtained in LTE-ε-TGOR scenario by 43.84 % and 62602 kg. kW − 1 , respectively. • A novel power and water production system based on gas turbine cycle is proposed. • Thermodynamic, economic, and environmental analyses are performed. • Payback period and net present value techniques are employed for economic analysis. • Multi-objective genetic algorithm is used to optimize the performances of the system. • TOPSIS decision-making method is applied to find the final optimum solutions. [ABSTRACT FROM AUTHOR]

Adsorption natural gas (ANG) is a technology in which natural gas is stored on the surface of porous materials at relatively low pressures, which are promising candidates for adsorption of natural gas. Adsorbent materials with a large surface area and porous structure plays a significant role in the ANG technology, which holds promise in increasing the storage density for natural gas while decreasing the operating pressure. Here, we demonstrate a facile synthetic method for rational construction of a sodium alginate (SA)/ZIF-8 composite carbon aerogel (AZSCA) by incorporating ZIF-8 particles into SA aerogel through a directional freeze-drying method followed by the carbonization process. The structure characterization shows that AZSCA has a hierarchical porous structure, in which the micropores originated from MOF while the mesopores are derived from the three-dimensional network of the aerogel. The experimental results show that AZSCA achieved high methane adsorption of 181 cm 3 ·g -1 at 65 bar and 298 K, along with higher isosteric heat of adsorption (Q st ) throughout the adsorption range. Thus, the combination of MOF powders with aerogel can find potential applications in other gas adsorption.

Developing highly efficient and stable photocatalysts is an effective method to achieve CO 2 photocatalytic reduction. Herein, PI/WO 3 aerogel photocatalyst was prepared by chemical amide reaction coupled with an ethanol supercritical drying technique. The novel aerogel photocatalysts exhibit excellent photocatalytic performance for reducing CO 2 into CO. In particular, PI/WO 3 -10 aerogel photocatalyst shows the highest yield of CO (5.72 μ mol g -1 h -1 ), which is ca 11-fold higher than that of the pristine PI aerogel. The high CO 2 reduction activity can be attributed to the Z-scheme structure, which enhances the separation of photo-generated electron - holes, and induces H 2 O oxidation on WO 3 nanosheets and CO 2 reduction on PI aerogel. The photocatalytic reaction mechanism of CO 2 when using PI/WO 3 aerogel photocatalyst is proposed., (© 2021 IOP Publishing Ltd.)

Various nitrogen (N)-doped carbon materials have been designed as efficient photocatalysts. For the first time, polyimide (PI) aerogels were calcined to be N-doped carbon photocatalysts at different temperatures. The structures of the carbonized polyimide aerogels (CPIs) vary with the carbonization temperature. The conductivity of the CPI increases with the improvement of calcination temperature, whereas the N content of the CPI decreases and the N state also changes. Thus, the electronic properties of the CPI are changed. The photocatalytic experiments certified that the PI aerogel calcined at 800 °C exhibited the highest photocatalytic performance. The chlortetracycline (CTC) degradation rate over CPI-800 aerogel is 2.3 times as much as that of PI aerogel due to the changed structure and properties of the CPI-800 aerogel.

In this study, a new nanoporous material comprising NiMoO 4 nanorods and Co 3 O 4 nanoparticles derived from ZIF-67 supported by a cellulose-based carbon aerogel (CA) has been successfully synthesized using a two-step hydrothermal method. Due to its chemical composition, the large specific surface and the hierarchical porous structure, the NiMoO 4 @Co 3 O 4 /CA ternary composite yields electrodes with an enhanced specific capacitance of 436.9 C/g at a current density of 0.5 A/g and an excellent rate capability of 70.7% capacitance retention at 5.0 A/g. Moreover, an advanced asymmetric supercapacitor (ASC) is assembled using the NiMoO 4 @Co 3 O 4 /CA ternary composite as the positive electrode and activated carbon as the negative electrode. The ASC device exhibits a large capacitance of 125.4 F/g at 0.5 A/g, a maximum energy density of 34.1 Wh/kg at a power density of 208.8 W/kg as well as a good cyclic stability (84% after 2000 cycles), indicating its wide applicability in energy storage. Finally, our results provide a general approach to the construction of CA and MOF-based composite materials with hierarchical porous structure for potential applications in supercapacitors., (Copyright © 2020, Wang et al.; licensee Beilstein-Institut.)