Coordinated Control of a Wind-Methanol-Fuel Cell System with Hydrogen Storage

This paper presents a wind-methanol-fuel cell system with hydrogen storage. It can manage various energy flow to provide stable wind power supply, produce constant methanol, and reduce CO2 emissions. Firstly, this study establishes the theoretical basis and formulation algorithms. And then, computational experiments are developed with MATLAB/Simulink (R2016a, MathWorks, Natick, MA, USA). Real data are used to fit the developed models in the study. From the test results, the developed system can generate maximum electricity whilst maintaining a stable production of methanol with the aid of a hybrid energy storage system (HESS). A sophisticated control scheme is also developed to coordinate these actions to achieve satisfactory system performance

The Controllable PVA-Chitosan Fiber Prepared by the Near-field Electro Spinning for Tissue Engineering

Abstract: The cells in natural tissues and organs have diverse shapes and arrangements in structure. The tissue engineering scaffolds which have a specific extracellular matrix structure can be prepared by electro spun fibers having a diverse arrangement in structure and thus guide adherent cells grow, proliferate and divide into the regenerative tissue or organs which have specific cell morphology and orientation structure. This study is based on a Near-Field Electros Pinning (NFES) process and uses Polyvinyl Alcohol (PVA) mixed chitosan, a non-toxic, good hydrophobic and biocompatible mixed materials, to prepare a micro/nano-fiber with controllable arrangement used in tissue engineering. The purpose of this research is the realization of getting the fiber with controllable arrangement. In this study, laboratory equipment will be built which integrates a feeding system, a high voltage electric field control system, a on-line image acquisition system and a motion control system of the collection platform. It focuses on the process parameters of the micro/nano direct writing of this material. Meanwhile, verifying the controllability of the implementation of the near-field electrospinning process for preparing composite fiber using this experiment platform

Self-organized Voids Revisited: Experimental Verification of the Formation Mechanism*

In this paper, several experiments were conducted to further clarify the formation mechanism of self organized void array induced by a single laser beam, including energy-related experiments, refractive-index-contrast-related experiments, depth-related experiments and effective-numerical-aperture experiment. These experiments indicate that the interface spherical aberration is indeed responsible for the formation of void arrays

Anthropogenic impacts on hyperbenthos in the coastal waters of Sishili Bay, Yellow Sea

A survey on the hyperbenthic communities was carried out in the coastal waters of Sishili Bay in the Yellow Sea in July 2009, to investigate the impact of putative anthropogenic activities related to the presence of a sewage outfall, a harbor and an aquaculture site on the benthic ecosystem. An Agassiz net trawl was used to collect hyperbenthos at 10 sampling stations. Species, diversity, abundance, and biomass were analyzed against water sample data and historical data obtained from records from nearby Yantai City. Fifty-two species were identified in the region, of which Crustacea were the most abundant taxon, followed by Echinodermata. Dominant species included five crustaceans, two echinoderms, one mollusk and one fish species. The results of a BIOENV analysis show that the concentrations of NO3-N and Chl-a were slightly positively correlated with hyperbenthic community structure, while other factors were negatively correlated, including sediment grain size and the percentage of TN and TOC in sediment. Abundance-Biomass Comparison (ABC method) curves indicate that the hyperbenthos in Sishili Bay had been disturbed by putative sources of human activities. Eight out of 10 stations were classified as "moderately perturbed" to "perturbed"

Integrating environmental and satellite data to estimate county-level cotton yield in Xinjiang Province

Accurate and timely estimation of cotton yield over large areas is essential for precision agriculture, facilitating the operation of commodity markets and guiding agronomic management practices. Remote sensing (RS) and crop models are effective means to predict cotton yield in the field. The satellite vegetation indices (VIs) can describe crop yield variations over large areas but can’t take the exact environmental impact into consideration. Climate variables (CVs), the result of the influence of spatial heterogeneity in large regions, can provide environmental information for better estimation of cotton yield. In this study, the most important VIs and CVs for estimating county-level cotton yield across Xinjiang Province were screened out. We found that the VIs of canopy structure and chlorophyll contents, and the CVs of moisture, were the most significant factors for cotton growth. For yield estimation, we utilized four approaches: least absolute shrinkage and selection operator regression (LASSO), support vector regression (SVR), random forest regression (RFR) and long short-term memory (LSTM). Due to its ability to capture temporal features over the long term, LSTM performed best, with an R2 of 0.76, root mean square error (RMSE) of 150 kg/ha and relative RMSE (rRMSE) of 8.67%; moreover, an additional 10% of the variance could be explained by adding CVs to the VIs. For the within-season yield estimation using LSTM, predictions made 2 months before harvest were the most accurate (R2 = 0.65, RMSE = 220 kg/ha, rRMSE = 15.97%). Our study demonstrated the feasibility of yield estimation and early prediction at the county level over large cotton cultivation areas by integrating satellite and environmental data

Development and characterization of magnetron sputtered self-lubricating Au-Ni/a-C nano-composite coating on CuCrZr alloy substrate

Compounding Au-Ni with carbon (C) lubricants is a feasible approach to improve its mechanical properties and wear performance. In this study, 3.5 μm-thick Au-Ni/C nanocomposite coatings with a low residual stress on CuCrZr substrates by magnetron sputtering were developed. Face-centered cubic and hexagonal close-packed stacking structures were both confirmed in the composite coatings based on transmission electron microscopy and X-ray diffraction analyses. Amorphous C (a-C) was confirmed to be the structure of C in the composite coatings, and its graphitization transition with an increase in the C content was validated by X-ray photoemission spectra and Raman spectroscopy. By compounding 0.88 wt% a-C, the hardness of the Au-Ni/a-C coating reached 400 HV, which is twice higher than that of the Au-Ni coating. The electrical resistivity of the Au-Ni/a-C coating is relatively stable with an increase in the a-C content. As graphitization occurred on the wear track, the produced composite coatings showed a minimum wear rate of 2.2 × 10−6 mm3/N·m under atmospheric conditions, which is half that of the Au-Ni reference coating. Under vacuum, the wear performance of the produced Au-Ni/a-C composite coatings was similar to that of the Au-Ni reference coating

Surfactant-assisted electrodeposition of Au–Co/WS2 self-lubricating coating from WS2 suspended cyanide electrolyte

In this study, Triton X-100 was used as the WS2 dispersion agent in the Au–Co cyanide electrolyte to deposit Au–Co/WS2 composite coatings. Probe sonication was applied to exfoliate the commercial WS2 powders to produce thinner and smaller WS2 flakes, which improved the stability of the WS2 particles in the electrolyte. According to the electrochemical analyses, the effects of adding Triton X-100 and WS2 particles to the electroplating process were investigated. Through material characterizations, WS2 particles were proved to be compounded into the Au–Co matrix and showed clearly {002} preferred orientation due to their flake structures. Tribological tests were performed under dry condition in 10−3 Pa vacuum against stainless steel 316L balls with diameters of 3 mm and a normal contact force of 2 N. The Au–Co/WS2 composite coatings that developed showed the minimum coefficient of friction and wear rate of 0.05 and 8 × 10−6 mm3/N·m, which are 5 times and 3 times lower than the Au–Co reference coating, respectively

Laboratory Calibration of a Field Imaging Spectrometer System

A new Field Imaging Spectrometer System (FISS) based on a cooling area CCD was developed. This paper describes the imaging principle, structural design, and main parameters of the FISS sensor. The FISS was spectrally calibrated with a double grating monochromator to determine the center wavelength and FWHM of each band. Calibration results showed that the spectral range of the FISS system is 437–902 nm, the number of channels is 344 and the spectral resolution of each channel is better than 5 nm. An integrating sphere was used to achieve absolute radiometric calibration of the FISS with less than 5% calibration error for each band. There are 215 channels with signal to noise ratios (SNRs) greater than 500 (62.5% of the bands). The results demonstrated that the FISS has achieved high performance that assures the feasibility of its practical use in various fields