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Durian shell, a biomass waste, was simply burned and then could serve as a heterogeneous catalyst for the transesterification reaction of palm oil with methanol at room temperature. The chemical composition, structure, and morphology of the catalyst were well-characterized by XRD, BET, SEM, TEM, EDS, TGA, FT-IR, and XPS measurement. With the preparation temperature rising to 350 °C, the maximum yield of the biodiesel could reach 94.1% at room temperature, and the optimum reaction conditions were 8 wt.% catalyst, 8:1 methanol/oil molar ratio, ad 2.5 h reaction time. The characterizations results indicated that K2O and K2CO3 existed on the surface of catalyst, and a moderate amount of carbon, which acts as a carrier, attributed to the activity of the catalyst. After repeating five times, the catalyst prepared at 350 °C showed better stability than other catalysts. This might be because the incomplete combustion of the remaining carbon slowed down the loss of K to some extent.

Korteweg-de Vries-type models attract people’s attention during the studies on the cosmic plasmas, planetary oceans and atmospheres. In this paper, on a generalized three-coupled Korteweg-de Vries system, symbolic computation comes to a hetero-Backlund transformation, while the Hirota method and symbolic computation bring about some bilinear forms and multi-solutions. Our results are dependent on the coefficients in that system.

Two-layer fluids are seen in fluid mechanics, thermodynamics and medical sciences. Lattices are seen in solid-state physics. In a two-layer liquid or a lattice, a ( $$3+1$$ )-dimensional generalised Yu–Toda–Sasa–Fukuyama equation is hereby studied with symbolic computation. Via the Hirota method, bilinear form and bilinear auto-Backlund transformation under certain coefficient constraints are obtained. Breather solutions are worked out based on the Hirota method and extended homoclinic test approach. Considering that the periods of breather solutions tend to infinity, we derive the lump solutions under a limit procedure. We observe that the amplitudes of the breather and lump remain unchanged during the propagation. Furthermore, we graphically present the breathers and lumps under the influence of different coefficients in the equation.

This study discusses a finite-time tracking controller for a rehabilitative training walker that imposes velocity constraints. The walker was described using a stochastic model through which the rehabilitee mass can randomly change, and a velocity constraint method was proposed to control the velocity input to every omniwheel based on a model predictive algorithm. This approach is novel in that the velocity constraint information obtained from the kinematics model was used to design the tracking controller based on the stochastic dynamic model, thus successfully constraining the actual velocity of walker as per the stochastic system. The nonlinear tracking controller was built for the stochastic rehabilitative walker to make the system’s finite time stable. Also, simulation and experiment were performed, and results confirmed that the proposed tracking control method with velocity constraints is very effective, so it may enable various rehabilitees to train safely.

Oceanic water-wave studies are attractive. Hereby, with a view to modelling the nonlinear and dispersive long gravity waves in two horizontal directions on the shallow water of an open sea or a wide channel of finite depth, we inquire into a generalized (2+1)-dimensional dispersive long-wave system, by virtue of the scaling transformations we hereby obtain, Bell polynomials and symbolic computation. As for the horizontal velocity and wave elevation above the undisturbed water surface, we find two branches of the hetero-Backlund transformations, two branches of the bilinear forms and two branches of the N -soliton solutions, with N as a positive integer. What we have obtained relies on the coefficients in the system.

The resonant nonlinear Schrodinger equation (RNLSE) with competing weakly nonlocal nonlinearity and fractional temporal evolution, which describes the propagation of optical solitons along the nonl...

The bandgap of the ternary chalcogenide Cu2SnS3 (CTS) can be tuned by alloying with Ge. The performance of CTS based solar cell devices with varies band gap grading profiles have been simulated with respect to the solar cells with a uniform band gap absorbing layer. It was revealed that band gap engineering geared to controlling the grading profile in the absorber layer lead to performance enhancement comparing to that of a device without band gap grading. Moreover, bandgap profiles with various back metal working function (φm) were simulated. An over 4–5% efficiency improvement was obtained due to the increasing φm with different band gap grading profile. The optimum PCE of 15.65%, 19.03% and 19.9% have been obtained with uniform, single and double band gap structures respectively. Moreover, the effects of various defects density on solar cell properties were investigated and the results indicate that there is a threshold of 1 × 1016 cm−3 for both acceptor/donor and neutral defects. The depth profile of the carrier recombination rate was calculated to understand of the fundamental device physics. The result show that a great improvement of both Voc and Jsc was obtained in the back surface grading structure cell comparing to that of the uniform bandgap cell due to the additional quasi-electric field associated to the affinity (conduction band) variation with position benefitting the carrier collection and reducing the back surface recombination and bulk recombination typically characterized by the diffusion length. A slight enhancement of short-circuit current density without significantly sacrificing the open-circuit voltage was obtained in the double band gap grading structure comparing to the single back grading owing to an increasement of front grading within the SCR.

As a notorious hazardous waste, biomass tar has for a long time been recognized as one of the key challenges throughout the progress in biomass gasification for renewable energy and chemical purpos...

BACKGROUND: Graphene‐supported nanocomposites are promising catalysts for their unique properties. Biosynthesis of such hybrid catalysts possesses several advantages over other methods such as less pollution. The palladium nanoparticle has versatile catalytic activities and its stability and activities can be significantly improved through hybridization with other nanomaterials including graphene. RESULTS: In this study, bimetallic palladium‐silver nanoparticles supported on graphene (Pd‐Ag/rGO) was prepared through one‐step biosynthesis using a bacterium Shewanella oneidensis MR‐1. Shewanella oneidensis MR‐1 synthesized Pd‐Ag/rGO through simultaneous reduction of silver nitrate (AgNO₃), palladium(II) nitrate (Pd(NO₃)₂) and graphene oxide (GO). The morphology and composition of the Pd‐Ag/rGO were characterized by transmission electron microscopy, energy dispersive X‐ray, X‐ray diffraction, X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy and Raman spectroscopy. Furthermore, the hydrogenation activity of synthesized Pd‐Ag/rGO was tested using 4‐nitrophenol as a model chemical at room temperatures and pressure. The Pd‐Ag/rGO showed the best catalytic performance when Pd/Ag ratio was 1:1 and bacterial concentration was 1.0 of OD₆₀₀ (optical density measured at a wavelength of 600 nm) for the preparation of Pd‐Ag/rGO. Therefore, the kinetic rate constant for 4‐NP reduction was 0.2413 min⁻¹ catalyzed by as‐prepared Pd‐Ag/rGO, which is listed as one of the top level reported catalysts for 4‐NP reduction. CONCLUSION: Therefore, this study demonstrated a material and energy‐saving method to synthesize hybrid nanoparticles supported on graphene with high catalytic activity. © 2019 Society of Chemical Industry

There are two important aspects in optimally processing the acoustic measurements: the establishment of the functional model and the refinement of the associated stochastic model. In most cases the functional model may be sufficiently well-established, but the stochastic model error has not received considerable attention and it still remains a challenging research topic in real-time positioning. The equal weight stochastic model (EWSM) commonly used at present is under the assumption of equal-precision observation, which is imprecise and not coincident with reality. The purpose of this paper is to develop an approach to obtaining more accurate weights of observables by real-time estimating the variance of observations. The inaccurate stochastic model effect is analyzed and the real time stochastic model (RTSM) estimated by using the least squares residual of observations is presented to improve the positioning accuracy. Simulation results have shown that the underwater positioning accuracy goes from 0.173 m to 0.157 m based on GPS Intelligent Buoy (GIB) by employing the real time stochastic model, while that can be improved from 0.426 m to 0.306 m based on surveying vessel (SV) when adopting RTSM. Both simulations based on GIB and SV indicate that real-time stochastic model can perform better than conventional equal weight stochastic model in positioning accuracy.

Zinc sulfide (ZnS) thin films have been prepared by chemical bath deposition followed by thermal annealing. The influence of sulphur (S) pressure on the morphological, structural and optical properties of the ZnS thin film has been investigated. The results show that the annealed ZnS thin films have more homogeneous morphology and better crystallinity compared with the as-deposited film. It was found that the crystallinity and mean grain size of ZnS films increase with the S pressure. Meanwhile, the transmittance of the film was significantly enhanced in the visible spectrum region with the increase of S vapor pressure, which may be attributed to the lower defects density of the film annealed at higher S vapor pressure. However, the optical band gap of ZnS thin films decrease with the increase of S pressure, which is associated with the larger grain size and higher crystallinity. The decreased band gap can adjust the conduction band offset of the buffer/absorber heterojunction in copper based semiconductor material (such as Cu(In,Ga)Se2, Cu(In,Ga)S2 or Cu2ZnSnS4)solar cell to a lower energy barrier to enhance the electron injection from absorber to ZnS buffer layer. According to the structural and optical properties analysis, the obtained ZnS thin films annealed at higher S pressure can potentially be used as better buffer layer of thin film solar cells.

A series of TiO2/biochar composite catalysts were prepared by the hydrolysis method for the degradation of methyl orange, where biochar was obtained from the pyrolysis of waste walnut shells. The catalysts were examined by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), photoluminescence spectroscopy (PL) and X-ray photoelectron spectroscopy (XPS), elemental analysis and ultra violet-visible diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activity results showed that the catalysts noted as CT0.1/1, CT0.2/2 and CT 0.5/1 exhibited higher catalytic activity than that of pure TiO2. Besides, catalyst CT0.2/1 exhibited the highest catalytic activity (the decolorization efficiency of 96.88% and the mineralization efficiency of 83.23% were obtained), attributed to the synergistic effect of biochar and TiO2, while CT1/1 possessed the lowest activity due to the shelter of light by the excess biochar. After 5 repeated use, the catalyst CT0.2/1 still exhibited rather high activity toward the degradation of MO, where the decolorization efficiency and mineralization efficiency of MO achieved 92.45% and 76.56%, and the loss of activity was negligible.

The dynamics of the reactive scatterings of the ground (Na(3S)) and first excited (Na(3P)) state sodium atoms from hydrogen fluoride (HF) molecules is investigated by performing comprehensive Coriolis-coupled quantum wave packet calculations on the recent ab initio potential energy surface (PES). In the Na(3S) + HF reaction, the nonadiabatic effect is found to be negligibly small, and the reactivity is significantly promoted by the initial vibrational excitations being in line with the available experimental result. Excellent quantitative agreement between theory and experiment is also achieved for the initial state specified integral cross sections and rate constants for v ≥ 3 vibrational states. However, the calculated rate constant for v = 2 significantly underestimates the experimental result. The possible cause for the disagreement is discussed in detail. For the Na(3P) + HF scattering, which can lead to the formation of either the ground state NaF + H product or Na(3S) + HF reactant via the harpooning process, the calculated result for the integral cross section shows excellent agreement with the available experimental result indicating the reasonable accuracy of the interstate coupling term of the employed PES.

In this paper, Lie symmetry method is applied to investigate the invariance properties of the time fractional Kolmogorov–Petrovskii–Piskunov equation with Riemann–Liouville derivative. In view of p...

We present an analytical framework to project adoption of household electric appliances under a number of scenarios with different levels of population, urbanization, household size, and per-capita income. This framework enables us to estimate the saturation (i.e., number of a particular electric appliance per household) and the extent of adoption (total number of a particular electric appliance owned in each province), and to assess the impact of each driver. We focus on six types of appliances: personal computer, air conditioner, microwave oven, refrigerator, washing machine and television, and project their adoption during the 2015–2050 period. The projections are conducted for forty-five scenarios that combine five levels of population growth, three levels of per-capita gross domestic product (GDP) and income growth, and three levels of change in household size. We find that, among the six appliances investigated, ownership of personal computers and air conditioning equipment will grow the most, and that the current differences in appliance saturation among provinces and between urban and rural regions will almost disappear by 2050. However, most of the appliances will be owned in urban centers in Eastern China, where the majority of the population will be concentrated. Income growth, combined with urbanization and a reduction in household sizes, increases the total number of appliances, while a reduction in population decreases the total number of appliances. The results can be used as key inputs for long-term electricity system planning and to explore the potential effects of policies to support End-Use Energy Efficiency and Demand Side Response.

Seasonal leachate from both sealed and operating landfill in the identical district were employed as the sole substrate in the Microbial Fuel Cell (MFC) to evaluate the power output performance and aqueous organic waste disposal. The electrical performance was characterized to study the power generation, while the Chemical Oxygen Demand (COD) removal ratio and Coulombic Efficiency (CE) were calculated to illustrate the substrate disposal effect. In addition, Scanning Electron Microscope (SEM) on the operated anode was conducted to preliminarily explain the microbial community difference, and the phylogenetic tree constructed on the cultivated microorganism was an insight into the dominant bacteria suitable for leachate degradation. It was found that the MFCs inoculated with seasonal leachate from both sealed and operating landfill could generate electricity successfully. Although the fresh leachate-inoculated MFCs had better electrical output performance (22.7-25.6 W/m

The utilization of computation resources and reconfiguration time has a large impact on reconfiguration system performance. In order to promote the performance, a dynamical self-reconfigurable mechanism for data-driven cell array is proposed. Cells can be fired only when the needed data arrives, and cell array can be worked on two modes: fixed execution and reconfiguration. On reconfiguration mode, cell function and data flow direction are changed automatically at run time according to contexts. Simultaneously using an H-tree interconnection network, through pre-storing multiple application mapping contexts in reconfiguration buffer, multiple applications can execute concurrently and context switching time is the minimal. For verifying system performance, some algorithms are selected for mapping onto the proposed structure, and the amount of configuration contexts and execution time are recorded for statistical analysis. The results show that the proposed self-reconfigurable mechanism can reduce the number of contexts efficiently, and has a low computing time.

In this paper, a (2+1)-dimensional generalized Hirota-Satsuma-Ito equation for the water waves is investigated. We obtain the N-soliton solutions according to the bilinear form. The M-lump solutions are obtained based on the N-soliton solutions, where N and M are the positive integers. We take $$M=2$$ and 3 to get the two- and three-lump solutions. Besides, three types of the hybrid solutions are discussed graphically, which contain the hybrid solutions between the one-lump wave and two-kink solitons, between the two-lump wave and one-kink soliton, and between the one-lump wave and breather wave.

As the most advanced environment-friendly production model in the international society, ecological agriculture of Chinese materia medica(CMM) is the only way for the development of modern agriculture. With the proposal of the declaration on ecolo-gical agriculture of CMM,quot;Don't grab land from farmland, don't be enemies of grass and insects, don't be afraid of barren slopes and forests, and live up to the green and green mountainsquot;, the ecological planting of CMM has blossomed all over the country, and formed a scientific theory, technology and model. Based on the theory and method of economics, this paper expounds the comprehensive benefits and development advantages of ecological agriculture of CMM from the perspectives of farmers(producers), patients(consumers) and the country. From the perspective of medicinal farmers, the input and output income of conventional agriculture and ecological agriculture of CMM such as Panax ginseng, Astragalus propinquus, Atractylodes lancea, and Bupleurum chinense were compared, and it was found that ecological agriculture of CMM had obvious advantages in net income, average annual income and input-output ratio, which could better promote farmers' income. From the perspective of patients, according to the same dose, the content of active ingredients in ecologically planted CMMs is significantly higher than that in conventionally-planted herbs, and the amount of effective substances taken by patients is also higher, so as to achieve better therapeutic effect. At the national level, ecological planting of CMM is the key to ensuring the high-quality development of CMM industry, increasing farmers' income, ensuring the safety of people's drug use and promoting the sustainable development of agriculture. It is also an important part of realizing the harmonious development of economy, society and environment and promoting ecological civilization. In general, the declaration on ecological agriculture of CMM embo-dies the core characteristics and goals of ecological agriculture, and also points of the path and vision of ecological agriculture of CMM in the future. The declaration will guide production practice, promote the benefit of farmers, and lay the foundation for the sustainable development of CMM industry.

The study is aimed through field experiments to study the effect of combined application of organic and chemical fertilizers on the growth and quality of Salvia miltiorrhiza, provide ideas for reducing fertilization while increasing the efficiency as well as improving the quality of produces. The experiment included 6 treatments viz., no fertilization(CK), full application of chemical fertilizer(F), 25% orga-nic fertilizer with 75% chemical fertilizer(M25), 50% organic fertilizer with 50% chemical fertilizer(M50), 75% organic fertilizer with 25% chemical fertilizer(M75), and fully apply organic fertilizer(M100). The results showed that:(1)from the perspective of yield and economic benefits, M75 was the best and M100 second;(2)for effective components, the combined application of organic and chemical fertilizers increased the content of main water-soluble components and the total content of effective components, among which M25 and M50 were better.

Caffeic acid and its oligomers are the main water-soluble active constituents of the traditional Chinese medicine(TCM) Arnebiae Radix. These compounds possess multiple biological activities such as antimicrobial, antioxidant, cardiovascular protective, liver protective, anti-liver fibrosis, antiviral and anticancer activities. The phenylpropanoid pathway in plants is responsible for the biosynthesis of caffeic acid and its oligomers. Glycosylation can change phenylpropanoid solubility, stability and toxic potential, as well as influencing compartmentalization and biological activity. In view of the important role played by de-glycosylation in the regulation of phenylpropanoid homeostasis, the biosynthesis of caffeic acid and its oligomers are supposed to be under the control of relative UDP-glycosyltransferases(UGTs). Through the data mining of Arnebia euchroma transcriptome, we cloned 15 full-length putative UGT genes. After recombinant expression using the prokaryotic system, the crude enzyme solution of the putative UGTs was examined for the glycosylation activities towards caffeic acid and rosmarinic acid in vitro. AeUGT_01, AeUGT_02, AeUGT_03, AeUGT_04 and AeUGT_10 were able to glycosylate caffeic acid and/or rosmarinic acid resulting in different mono-and/or di-glycosylated products in the UPLC-MS analyses. The characterized UGTs were distantly related to each other and divided into different clades of the phylogenetic tree. Based on the observation that each characterized UGT exhibited substrate or catalytic similarity with the members in their own clade, we supposed the glycosylation abilities towards caffeic acid and/or rosmarinic acid were evolved independently in different clades. The identification of caffeic acid and rosmarinic acid UGTs from A. euchroma could lead to deeper understanding of the caffeic acid oligomers biosynthesis and its regulation. Furthermore, these UGTs might be used for regiospecific glycosylation of caffeic acid and rosmarinic acid to produce bioactive compounds for potential therapeutic applications.