Research on the adjustment model of ventilation characteristic parameters based on integrated method of circuit and path

Ventilation characteristic parameters are the base of ventilation network solution; however, they are apt to be affected by operating errors, reading errors, airflow stability, and other factors, and it is difficult to obtain accurate results. In order to check the ventilation characteristic parameters of mines more accurately, the integrated method of circuit and path is adopted to overcome the drawbacks caused by the traditional path method or circuit method in the digital debugging process of ventilation system, which can improve the large local error or the inconsistency between the airflow direction and the actual situation caused by inaccuracy of the ventilation characteristic parameters or checking in the ventilation network solution. The results show that this method can effectively reduce the local error and prevent the pseudo-airflow reversal phenomenon; in addition, the solution results are consistent with the actual situation of mines, and the effect is obvious.     

Kinetic characterization for hemicellulose hydrolysis of corn stover in a dilute acid cycle spray flow-through reactor at moderate conditions

The kinetic characterization of hemicellulose hydrolysis of corn stover was investigated using a new reactor of dilute acid cycle spray flow-through (DCF) pretreatment. The primary purpose was to obtain kinetic data for hemicellulose hydrolysis with sulfuric acid concentrations (10-30 kg m⁻³) at relatively low temperatures (90-100 °C). A simplified kinetic model was used to describe its performance at moderate conditions. The results indicate that the rates of xylose formation and degradation are sensitive to flow rate, temperature and acid concentration. Moreover, the kinetic data of hemicellulose hydrolysis fit a first-order reaction model and the experimental data with actual acid concentration after accounting for the neutralization effect of the substrates at different temperatures. Over 90% of the xylose monomer yield and below 5.5% of degradation product (furfural) yield were observed in this reactor. Kinetic constants for hemicellulose hydrolysis models were analyzed by an Arrhenius-type equation, and the activation energy of xylose formation were 111.6 kJ mol⁻¹, and 95.7 kJ mol⁻¹ for xylose degradation, respectively.     

Co‐effect of bis(cyclohexanone) oxalyldihydrazone and copper(II) ion on the corrosion of cold rolled steel in 0.5 M hydrochloric acid solution

Effects of bis(cyclohexanone) oxalyldihydrazone (BCO) and copper(II) ion (Cu²⁺) on the corrosion of cold rolled steel (CRS) in 0.5 M hydrochloric acid (HCl) solution were investigated using Tafel polarization curve and electrochemical impedance spectroscopy (EIS) at 20 °C. Results elucidate that the inhibition efficiency increases with increase in BCO concentration, and the addition of 10^?5 M Cu²⁺ significantly enhances the inhibition efficiency of BCO. Polarization curve results elucidate that the single BCO acts as a mixed‐type inhibitor while the combination of Cu²⁺ and BCO acts as cathodic inhibitor. Ultraviolet and visible spectrophotometer (UV–Vis) results show that BCO molecules do not interact with Cu²⁺ and Fe²⁺ in 0.5 M HCl solution. Atomic force microscope (AFM) result indicates that a protective layer forms on CRS surface after immersion in 0.5 M HCl containing BCO in the absence and presence of Cu²⁺. The adsorption of BCO is found to follow the Langmuir adsorption isotherm in the presence and absence of Cu²⁺. The mechanism of typically chemical adsorption is proposed via the value of free energy of adsorption (ΔG) in the presence of BCO and Cu²⁺.     

Bio‐electrochemical denitrification by a novel proton‐exchange membrane electrodialysis system—a batch mode study

BACKGROUND: Contamination of nitrate in ground and surface water has become an ever‐increasing and serious environmental problem. Biological methods hold the promise of converting nitrate into harmless nitrogen. A novel denitrification system which combines proton‐exchange membrane electrodialysis with simultaneous bio‐electrochemical autotrophic denitrification has been developed. The proton‐exchange membrane was used to transfer current and to exclude oxygen or other oxidative chemicals generated in the anode reaction. The H₂ generated by the cathode was utilized by autotrophic denitrifying microorganisms in the cathode cell to reduce nitrate. In this study, the transport of H⁺, a denitrification kinetics model and factors influencing the denitrification rate were explored in batch mode. RESULTS: The addition of 0.03 mol L^?1 H₂SO₄ into the anode cell enhanced proton transport and maintained the pH of the cathode cell in an appropriate range for biological denitrification. The denitrification rate was affected by applied current and biomass. Under adequate current conditions, the kinetics of the denitrification process followed a zero‐order kinetics model; the average denitrification rate for unit biomass was calculated to be 9.36 mg NO₃^?‐N VSS g^?1 h^?1. CONCLUSIONS: Results indicate that the system is suitable for denitrification. Owing to its simple structure and operation, it has the potential for use as a system to reduce nitrate in water. Copyright © 2010 Society of Chemical Industry     

Structural and mechanical characteristics of porous 316L stainless steel fabricated by indirect selective laser sintering

Selective laser sintering (SLS) technique is capable of rapidly fabricating customized implants with porous structure. A simple encapsulation process was developed to coat 316L stainless steel (316L SS) powder with ethylene-vinyl acetate copolymer (EVA). Subsequently, porous 316L SS was prepared by SLS preforming of EVA-coated metal powders, debinding and sintering in hydrogen atmosphere. The effects of processing parameters on pore characteristics and mechanical properties were analyzed. The results indicate that the porosity of green body mainly depends on laser energy density, while the pore features and mechanical properties of sintered specimens are largely dominated by sintering temperature. After sintering at 1100–1300 °C, the average pore size and porosity are 160–35 μm and 58–28%, respectively. In addition, the elastic modulus and compressive yield strength are 1.58–6.64 GPa and 15.5–52.8 MPa, respectively. It is revealed that the pore structural parameters and mechanical properties of the as-sintered porous 316L SS can be controlled readily to match with those of cancellous bone by modification of SLS processing parameters and subsequent sintering temperature.     

Chinese university students’ knowledge and attitudes regarding forest bio-energy

The present study examines Chinese university students’ attitudes and knowledge regarding energy, specifically towards forest bio-energy in their country. The study was based on opinions of students from Northwest Agriculture and Forestry University (NWAFU) in China and it was conducted using a questionnaire completed by 441 students. The students’ attitudes are seen as highly relevant because they are considered as both potential consumers and possible experts in the field of bio-energy. Their activities influence how the future energy markets will likely develop. The results revealed various interesting facets of the students’ views regarding energy usage. Of particular interest is the students’ positive attitude towards renewable energy in general, but slightly less positive towards forest bio-energy. However, the respondents expected to receive more information and knowledge about renewable energy and forest bio-energy. Moreover, it can be concluded that the dissemination of knowledge through different sources (e.g. teaching in school, information available on the Internet and other media channels) is an increasingly important aspect regarding energy issues. The results of this study can provide information of the perceptions of young educated people on energy policy issues and thus serve political decision-making processes for the future options concerning the development of forest bio-energy in China. Finally, the outcome of this study indicates that further environmental and energy education in China is urgently needed.     

市政道路路面的养护及维修技术探析

在如今经济飞速发展的时代,道路已经变得非常重要。因此,我们对道路的维护就显得十分重要,首先要学会怎样保护好道路,尽量延长它的使用寿命,要运用科学的手段对道路进行维护,达到流畅的程度。本文研究了路面维修相关理论,查阅过大量资料,并且深入探讨过,所以笔者的观点还是具有代表性的。     

连铸坯轧板探伤不合的原因及采取的工艺措施

本文着重对舞钢连铸坯轧板产生探伤不合的原因进行分析，阐述了钢中夹杂物和铸坯凝固过程中的偏析对探伤因素的影响，从而在生产过程中采取相庆的措施，使钢板探伤合格率得到有效的提高。     

聚(苯乙烯-丙烯酸)载体铁组成因素对其催化活性的影响

制备了不同铁含量、不同功能团含量的聚 (苯乙烯丙烯酸 )铁配合物 ( SAAC· Fe)。考查了 Fe含量和功能团 ( COOH)含量与催化活性的关系。发现当 COOH含量在 1 .7～ 3.6mmol/g范围内 ,Fe/COOH(摩尔比 )在 0 .2时催化活性最高。聚丁二烯的微观结构不受上述因素的影响     

定量求解重力谷糙分离机工作面上物料的运动

定量求解重力谷糙分离机工作面上物料的运动较为困难，迄今尚未见有文献报道，但这一问题可采用解析和数值解结合的方法求解。文中详细介绍了具体步骤和实例计算结果。