Effect of hydrogen and LPG addition on the efficiency and emissions of a dual fuel diesel engine

This paper presents some experimental investigations on dual fuel operation of a 4 cylinder (turbocharged and intercooled) 62.5 kW gen-set diesel engine with hydrogen, liquefied petroleum gas (LPG) and mixture of LPG and hydrogen as secondary fuels. Results on brake thermal efficiency and emissions, namely, un-burnt hydrocarbon (HC), carbon monoxide (CO), NO_x and smoke are presented here. The paper also includes vital information regarding performances of the engine at a wide range of load conditions with different gaseous fuel substitutions. When only hydrogen is used as secondary fuel, maximum enhancement in the brake thermal efficiency is 17% which is obtained with 30% of secondary fuel. When only LPG is used as secondary fuel, maximum enhancement in the brake thermal efficiency (of 6%) is obtained with 40% of secondary fuel. Compared to the pure diesel operation, proportion of un-burnt HC and CO increases, while, emission of NO_x and smoke reduces in both cases. On the other hand, when 40% of mixture of LPG and hydrogen is used (in the ratio 70:30) as secondary fuel, brake thermal efficiency enhances by 27% and HC emission reduces by 68%. Further, shortcoming of low efficiency at lower load condition in a dual fuel operation is removed when a mixture of hydrogen and LPG is used as the secondary fuel at higher than 10% load condition.     

PWM调压的高速电磁开关阀双电压驱动器研究

分析了影响高速电磁开关阀开启和关闭特性的电气因素,设计了一种PWM调压的高速电磁开关阀双电压驱动器,构建了高速电磁开关阀动态特性试验平台,验证了该驱动器改善高速电磁开关阀动态特性的有效性.     

Challenges in hot-dip galvanizing of high strength dual phase steel: Surface selective oxidation and mechanical property degradation

In this work, the two challenges in hot-dip galvanizing of high strength dual phase steel such as surface selective oxidation and mechanical property degradation were discussed. It was shown that the external selective oxidation occurred at low dew point − 30 °C caused the full coverage of oxides, which is a problem for reactive wetting by molten zinc. Although increase of dew point to + 10 °C decreased the surface coverage of oxides, the formation of internal oxides consumed the alloying element and accumulated in the subsurface area in a large scale. Furthermore, the heat treatment parameters of hot-dip galvanizing, i.e. cooling rate after inter-critical annealing and the 460 °C-isothermal soaking time influenced the mechanical properties.     

Zinc oxide (ZnO) grown on flexible substrate using dual-plasma-enhanced metalorganic vapor deposition (DPEMOCVD)

This study investigates the temperature dependence of zinc oxide (ZnO) grown on polyestersulfone (PES) flexible substrates using the dual plasma-enhanced metal–organic chemical vapor deposition (DPEMOCVD) system. The proposed method uses a direct voltage (DC) and radio-frequency (RF) plasma system. The group-VI precursor, oxygen (O₂), can be completely ionized by the DC plasma system. The effect of optimal DC plasma power on ZnO thin films is thoroughly investigated using X-ray diffraction (XRD). The experimental results indicate that the crystalline structure and optical and electrical properties of ZnO thin films grown on PES substrates are dependent on the deposition temperature. The optimum deposition temperature for ZnO thin films deposited on PES substrates is 185 °C, whereas the DC and RF plasma power is 1.8 W and 350 W, respectively. Additionally, the wettability characteristic regarding the UV irradiation time was assessed by measuring the water contact angle. Under the UV irradiation for 60 min, the ZnO film grown at 185 °C represents a low contact angle of 5°, which approaches to a superhydrophilic surface.     

An evaluation of the statistics of steel material model parameters

In robustness studies, variations of material properties are often represented by simple assumptions, such as scaling of stress-strain relations, often due to lack of knowledge or deeper understanding of the material physics and the material model applied. By performing material characterisation tests on several batches of a DP600 steel and fitting a phenomenological material model to each batch, this paper studies the dispersion of material model parameters, as well as correlations between both experimental and model parameters. It is concluded that some of the characterisation tests may be omitted in the future, due to correlations found between parameters. The results may also be applied in a robustness study by inversely using the retrieved statistics to generate reasonable new sets of material model parameters. The methodology presented may be adopted for any other type of material characterisation process.     

双端面机械密封的封液系统改造

分析双端面机械密封的结构形式,根据实际情况,对其封液系统进行改造,确保机泵的稳定运行。     

特低渗透油田开发综合配套技术—濮城油田沙三中6—10层系应用分析

濮城油田沙三中6－10层系油藏开发设计时合理部署注采井网，应用双靶定向井钻井技术，采用高压增注技术，利用高效射孔技术和整体压裂等技术，改造油层，补充地层能量，避免了采油井暴性水淹。采用小泵深抽工艺，增大生产压差，保证油井具有较高的产能。沙三中6－10层系特低渗透油藏的开发实践经验，对同类油藏的开发具有一定的借鉴意义。     

Effect of water quench process on mechanical properties of cold rolled dual phase steel microalloyed with niobium

Effect of water quench process on tensile properties of microalloyed dual phase (DP) steel was investigated. The results showed that the tensile strength and yield strength decrease while total elongation increases with decreasing quenching temperature. Different quenching temperatures lead to not only different amounts of martensite, but also different volume fractions of new ferrite. Due to exemption of precipitation strengthening, new ferrite will contribute to not only the increase of ductility, but also the improvement of microalloyed DP steel strength.     

双栅氧CMOS工艺研究

双栅氧工艺(dual gate oxide)在高压CMOS流程中得到了广泛的应用,此项工艺可以把薄栅氧器件和厚栅氧器件集成在同一个芯片上.文章介绍了常用的两种双栅氧工艺步骤并分析了它们的优劣.在此基础上,提出了一种实现双栅氧工艺的方法.     

双波长分光光度法测定组合浆料组分含量的研究

对同时测定组合浆料中ＰＶＡ和淀粉磷酸酯含量的双波长分光光度法进行了研究，介绍了双波发光光度法测定原理和方法，并对测试结果进行了分析，讨论，实验证明，用该方法同时测定双组分含量，即简单又准确。