Totally found 4346 items.

  • [资讯] 1 H HR-MAS NMR-based metabolomics study of different persimmon cultivars (Diospyros kaki) during fruit development
    1 H HR-MAS NMR spectroscopy was used to track the metabolic changes throughout the whole development of astringent (‘Giombo’) and non-astringent (‘Fuyu’) cultivars of persimmon (Diospyros kaki). The NMR data revealed the low concentration of amino acids (threonine, alanine, citrulline and GABA) and organic acids (malic acid). In addition, the signals of carbohydrates (sucrose, glucose and fructose) seemed to play the most important role in the fruit development. In both cultivars, the growth was characterized by fluctuating sucrose concentration along with a constant increase in both glucose and fructose. In the initial growth stage, the polyphenol composition was quite different between the cultivars. Gallic acid was detected throughout the growth of ‘Giombo’, while for ‘Fuyu’, signals of polyphenols disappeared over time. Additional multivariate analysis suggested that these cultivars share many metabolic similarities during development. These findings might help the comprehension of fruit development, which in turn, impacts the quality of the fruits.
  • [资讯] Membrane distillation hybridized with a thermoelectric heat pump for energy-efficient water treatment and space cooling
    The current concept for cooling the indoors is far from ideal with respect to the total energy consumed and waste discharged. A novel concept for improving the energy efficiency is proposed via hybridizing the heat pump with a membrane distillation (MD) unit for simultaneous space cooling and water treatment. MD is well-acknowledged for utilizing low-quality waste heat for water treatment, which makes it feasible for coupling with a heat pump to make use of both the hot and cold reservoirs of the pump. Accordingly, the objective of the current effort was to investigate via experiments the efficacy of a thermoelectric heat pump coupled with a sweep-gas MD system (T-SGMD) by measuring the cooling capacity, condensate production and power consumption. The results from this study can be extended to other heat pumps. Three key highlights emanated from this study. Firstly, condensate production per unit energy consumed can be doubled with the T-SGMD system relative to thermoelectric dehumidification alone. Secondly, cool air recycle affected the condensate flux the most without a drastic loss of cooling compared to other tested parameters during the operation of the T-SGMD. Lastly, the T-SGMD system was able to provide an increase in condensate produced per unit energy without a loss in cooling capacity per unit energy input. These advantages of coupling heat pumps with MD, leveraging on the current advancements in MD, is promising for a hybridized system for decentralized water treatment, dehumidification and space cooling.
  • [资讯] Screening 89 Pesticides in Fishery Drugs by Ultrahigh Performance Liquid Chromatography Tandem Quadrupole-Orbitrap Mass Spectrometer
    Multiclass screening of drugs with high resolution mass spectrometry is of great interest due to its high timeefficiency and excellent accuracy. A highscale, fast screening method for pesticides in fishery drugs was established based on ultrahigh performance liquid chromatography tandem quadrupoleOrbitrap highresolution mass spectrometer. The target compounds were diluted in methanol and extracted by ultrasonic treatment, and the extracts were diluted with MeOHwater (1:1, vv) and centrifuged to remove impurities. The chromatographic separation was performed on an Accucore aQMS column (100 mm 2.1 mm, 2.6 m) with gradient elution using 0.1% formic acid in water (containing 5 mmolL ammonium formate) and 0.1% formic acid in methanol (containing 5 mmolL ammonium formate) in Full ScanddMS2 (TopN) scan mode. A screening database, including mass spectrometric and chromatographic information, was established for identification of compounds. The screening detection limits of methods ranged between 1500 mgkg, the recoveries of real samples spiked with the concentration of 10 mgkg and 100 mgkg standard mixture ranged from 70% to 110% for more than sixty compounds, and the relative standard deviations (RSDs) were less than 20%. The application of this method showed that target pesticides were screened out in 10 samples out of 21 practical samples, in which the banned pesticide chlorpyrifos were detected in 3 out of the 10 samples.
  • [资讯] Decision-making in safety efforts: Role of the government in reducing the probability of workplace accidents in China
    A sequential game model is built to analyze the interaction between the government’s effort in safety regulation and the company’s safety effort based on the case in China. An equilibrium solution for the game model is given, and a theoretical analysis concerning the impact of the governments’ regulation on the solution is illustrated. The results show that the probability of workplace accidents can be reduced by increasing unit penalty cost under a given condition. The government should divide workplace accidents into two categories based on the magnitude of the accident: small accidents and large accidents. For accidents classified as small, the larger the magnitude of the accident is, the smaller is the unit penalty cost needed to reduce the accident’s probability. For accidents classified as large, a same unit penalty parameter can be set, which helps to simplify accident management. In addition, the government can reduce the probability of workplace accidents by changing the taxation percentage according to the inflexion point of the relationship between the company’s safety effort and the taxation percentage. The findings of this paper provide some useful insights for Chinese governments on reducing accident probability by resetting their regulation parameters.
  • [资讯] Li3Ti4CoCrO12, a new substituted lithium titanium compound as anode material for lithium ion batteries
    A new compound Li3Ti4CoCrO12, used as an anodic material for LIBs, was successfully prepared by nanomilling enhanced solidstate reaction method. Retrieved refinement of the Xray diffraction (XRD) profile indicated that the material crystallizes in an ordinary Fd3m lattice space group in which the substituted ions Co2 and Cr3 occupy the original Li and Ti (4) lattice positions, respectively. Upon cyclic voltammetry (CV) measurement, the sample showed a pair of redox process peaking at 1.44 V1.53 V, implying that only Ti3Ti4 redox pair was involved in the electrochemical process. Electrochemical impedance spectroscopy (EIS) test suggested that both the low interfacial resistance (8.56 Omega) and the high Li ion diffusion (9.86 x 10(10) cm(2).S1), caused by the mesoporous nature of the anode powder, could be regarded as the important factors for the outstanding electrochemical behavior of the new anode material. The results imply that the synthesized compound Li3Ti4CoCrO12 has high potential for the application in lithium secondary batteries.
  • [资讯] Explosion of power capacitors in a change of transformers with reactive power compensation
    In industrial activities, the load increase with a more production requirements and overloading, however, in some case the power transformer requires to change for a failure or a contingency stage. In this case, a real engineering failure analysis is done for the shunt capacitors explosion in an industrial facility.A new methodology is proposed for the Engineering failure Analysis for capacitors explosions with overloading power transformers condition, the individual and system assessment with an international standard review is developed for a better understanding in the solution proposal. With this new methodology the following Standards should be updated: IEC 60931, IEC 60871, IEC 60110, IEC 60143, IEC 60252, IEC 60358, IEC 61017, IEC 61048 and IEC 61049. The degradation analysis for the power transformer are considered too with the following international standards analysis: Laboratec, Duval, ABNT IEC 60599, IEEE Rogers, IEC 60599 and CIGRE CS 15.A new recommendation for an international standard is proposed, for the critical scenario, contingency stage and finally the solution with the methodology in a real case study in a Gold mining located in Colombia.
  • [资讯] Advances in the preparation of hydrogel for wastewater treatment: A concise review
    Hydrogels are being investigated recently for wastewater treatment. These polymeric networks permit their functional group alterations imparting high binding affinity for different contaminants in wastewater. Their innate ability to imbibe huge volume of water qualifies it for a smart material for water remediation. In this review recent advancements in the modifications and types of hydrogels with particular emphasis on adsorption capacity of metal ions and dyes is presented. In addition, through a comparative approach, adsorption mechanism, kinetic, isotherm and related thermodynamics parameters of the modified hydrogels have been discussed. It gives a detailed account of the work done by different authors on the synthesis, composition, functionality and contaminant removal mechanism. It also provides an indepth perspective on the advantages and limitations in the application of hydrogels for wastewater treatment.
  • [资讯] Soft elastomeric composite materials with skin-inspired mechanical properties for stretchable electronic circuits
    The stretchable version of electronic circuits harnesses commercial chip scale components to achieve complex functionality and mechanical deformability, which represents an emerging technology to expand the application of conventional electronics on rigid wafers. The bottleneck lies in the lack of a robust approach for the collective integration of offtheshelf components into a reliable system. In this study, an elastomeric composite material with skinlike mechanical responses and spatially heterogeneous rigidity is reported as an attractive platform for stretchable circuit systems. The approach utilizes a high modulus microstructure embedded in the matrix of a soft elastomer to achieve programmable mechanical properties, thereby offering selective strain isolation for fragile components and overall protection against excessive loads. A low cost procedure involving laser ablation and blade coating is established to create the composite material matching with the circuit design. In addition, ultrasonic atomization of liquid metal into microparticles allows flexible preparations of deformable conductors in the forms of interconnects and contacts. An LED matrix is demonstrated as a prototype circuit system with excellent durability to withstand repetitive stretching and external impacts. Stretchable circuit systems based on soft elastomeric composite materials may find potential uses in health monitoring, mechatronic prosthetics, and soft robotics.
  • [资讯] Analysis of explosion accidents with heat recirculation dryers and their inherent safety improvement
    The explosion accidents occurred at the drying workshops in China were found mostly to be caused by explosive gas mixtures formed in drying chambers. During the heat recirculation drying of surface coatings, solvent vapors are released forming explosive mixtures when the lower explosion limit of their concentration in air is reached. The analysis of exploded dryers and the numerical modeling served their inherent safety improvement ideas presented in this research. The improvement in heat recirculation drying safety was achieved with evacuation and oxygen concentration control using nitrogen. The drying gas double circuits at inlet and outlet of the drying chamber were installed to maintain an inert gas minor excess pressure (≤0.1 MPa) in the drying chamber. Oxygen concentration thus did not exceed 7.0 vol %. The drying time was substantially shortened, and the energy consumption was thus reduced for 67%. The present study provides an explosion prevention strategy with regard to inherent safety of heat recirculation dryers in design and operation.
  • [资讯] Investigation of the explosion‐related parameters and their influence on the severity of an explosion involving aluminum dust
    Aluminum dust is a serious explosion hazard in the process industry. Therefore, any risk assessment requires knowledge of the data relating to the explosion hazard of the dust. We report on some experimental results that explain the influence of the particle size and the distribution, the specific surface area and the combustible components of various aluminum dusts on their sensitivity and the severity of an aluminumdust explosion. Three samples of aluminum powder with different particle sizes were analyzed. The results reveal an extremely high maximum pressure rise for one of the samples, which can be assigned to a hybrid explosion caused by the presence of combustible additives in the dust. The results were compared with available literature data for similar dusts, which show that one of the analyzed powders has to be given a higher classification due to its larger K st value, which also means a greater risk of explosion. The presence of a combustible additives in the dust reduces the sensitivity of the aluminum powder, but simultaneously substantially increases the severity of a dust explosion. It can be concluded that two of three investigated cases show a significant difference compared to the literature data, but for different reasons. 2019 American Institute of Chemical Engineers Process Saf Prog: e12047 2019
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