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61.
Ultrasonic elliptical vibration cutting of titanium alloy Ti–6Al–4V is investigated in this research. Because products made of Ti–6Al–4V alloy are usually designed for possessing low-rigidity structures or good-quality cut surfaces, machining requirements such as low cutting forces and slow rate of tool wear need to be fulfilled for realization of their precision machining. Therefore, the ultrasonic elliptical vibration cutting is applied as a novel machining method for those products. Machinability of Ti–6Al–4V alloy by the ultrasonic elliptical vibration cutting with cemented carbide tools is examined to figure out suitable cutting conditions for precision machining of Ti–6Al–4V alloy. As experimental results, generated chips, cutting forces, and profiles of cut surfaces are indicated. A forced vibration problem occurred due to the segmented chip formation, which is also well-known in the ordinary non-vibration cutting. Therefore, characteristics of the forced vibration due to the chip segmentation are investigated in this research. Through the experiments, it is found that the frequency and magnitude of the forced vibration have relation with the average uncut chip thickness and cutting width. Especially, it is found that the averaging effect can suppress the forced vibration, i.e. the chip segmentation tends to occur randomly over the large cutting width, and hence the force fluctuations with random phases tend to cancel each other as the cutting width increases relatively against the average uncut chip thickness. Based on the investigations, a new practical strategy to suppress the forced vibration due to chip segmentation is proposed and verified. Using the proposed method significantly decreased cutting forces and good quality of surfaces are obtained when the forced vibration is suppressed compared to the ordinary non-vibration cutting results. Therefore, the results suggest that the precision machining can be realized without sacrificing the machining efficiency by increasing the width of cut and decreasing the average uncut chip thickness. 相似文献
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针对国内外风电和工业齿轮箱轻量化的设计趋势,较低的安全系数对齿轮齿根弯曲强度提出了更为严格的要求。研究表明,在材料技术和齿形设计难以再优化的情况下,滚齿加工的粗糙度,尤其是齿根部位的粗糙度对齿轮弯曲强度的影响尤为敏感。针对滚齿工艺过程,从滚齿加工参数、刀具前刀面粗糙度和刀具刃口圆角三方面进行分析,验证其对齿根粗糙度的影响。 相似文献
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66.
阐述金川集团化工厂530 kt/a铜冶炼烟气制酸系统扩能改造和余热回收前存在的问题,在遵循尽可能保留现有工艺管线和保证余热高效回收的原则上对转化工艺进行改造完善,将转化流程由原设计的“3+1/Ⅳ.Ⅰ-Ⅲ.Ⅱ”四段转化改为“3+2/Ⅴ.Ⅰ-Ⅲ.Ⅱ.Ⅳ”五段转化工艺流程,研发适合冶炼烟气制酸系统的分离型热管余热回收工艺技术.生产实践证明,该工艺在确保转化热平衡的基础上提升转化率,优化系统工艺技术指标,实现回收转化中温位富余热量生产饱和蒸汽,保证制酸系统与铜冶炼系统的匹配化生产,节能减排效益可观. 相似文献
67.
Francielo Vendruscolo 《国际能源研究杂志》2015,39(3):293-302
Hydrogen is a clean energy carrier with great potential to be an alternative fuel. Anaerobic hydrogen fermentation seems to be more favorable, since hydrogen is yielded at high rates and various organic waste and wastewater enriched with carbohydrates as substrate result in low cost for hydrogen production. Abundant biomass from various industries could be a source for biohydrogen production where combination of waste treatment and energy production would be an advantage. Carbohydrate‐rich nitrogen‐deficient solid wastes such as starch residues can be used for hydrogen production by using suitable bioprocess technologies. Alternatively, converting biomass into gaseous fuels, such as biohydrogen, is possibly the most efficient way to use these agroindustrial residues. This review summarizes the potential of starch agroindustrial residues as a substrate for biohydrogen production. Types of potential starch agroindustrial residues, recent developments and bio‐processing conditions for biohydrogen production will be discussed. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
68.
Sustainable cements containing 25 wt% of different types of recycled glass have been investigated as a supplementary cementing material in order to highlight the role of glass chemical composition during the hardening process. Glass formers, stabilizers and modifiers regulate the glass dissolution in the alkaline environment during cement hydration. As a consequence, pozzolanic reaction and/or alkali–silica reaction are strictly related to the glass chemical composition. The mechanical and microstructure characterizations of mortar samples containing glass blended cements and un-reactive aggregates allow to determine which oxides in the glass have to be carefully monitored to avoid deleterious reactions. 相似文献
69.
通过反平衡法计算废碱焚烧炉热效率、产汽量及可变成本,建立了废碱焚烧运行成本模型,并计算分析了可变成本与燃料类型、组成、投碱量、尾气含氧量等因素的关联性。结果表明:随着混合燃料中干气比例提高,可变成本下降;仅使用辅助燃料渣油时,随着渣油量增加,可变成本不断增加,并出现加速拐点,急速增加;仅使用干气作辅助燃料时,随着干气量增加,投碱量减少,可变成本不断降低,并出现加速拐点,急速下降;随着尾气含氧量增加,锅炉的燃烧效率不断下降,可变成本不断增高;针对干气充足、干气不充足以及全部使用燃料油时,提出了相应的经济运行模式,并将其应用于指导生产,经济效益明显。 相似文献
70.
《International Journal of Hydrogen Energy》2021,46(57):29108-29125
In terms of infection control in hospitals, especially the Covid-19 pandemic that we are living in, it has revealed the necessity of proper disposal of medical waste. The increasing amount of medical waste with the pandemic is straining the capacity of incineration facilities or storage areas. Converting this waste to energy with gasification technologies instead of incineration is also important for sustainability. This study investigates the gasification characteristics of the medical waste in a novel updraft plasma gasifier with numerical simulations in the presence of the plasma reactions. Three different medical waste samples, chosen according to the carbon content and five different equivalence ratios (ER) ranging from 0.1 to 0.5 are considered in the simulations to compare the effects of different chemical compositions and waste feeding rates on hydrogen (H2) content and syngas production. The outlet properties of a 10 kW microwave air plasma generator are used to define the plasma inlet in the numerical model and the air flow rate is held constant for all cases. Results showed that the maximum H2 production can be obtained with ER = 0.1 for all waste samples. 相似文献