Thermoacoustic effect of traveling-standing wave

In order to improve thermoacoustic efficiency, the thermoacoustic devices have been developed from standing wave devices to traveling wave devices. Actually, the acoustic field in practical thermoacoustic devices is neither a pure traveling wave nor a pure standing wave. The thermoacoustic effect is the hybrid effect of traveling wave component and standing wave component. Therefore, the thermoacoustic effect of traveling-standing wave will be study in this paper. Firstly, the thermoacoustic conversion performance of the traveling-standing wave are analyzes qualitatively by combining the thermoacoustic conversion performance of the traveling wave with those of the standing wave. Then, based on the basic thermoacoustic formulas, the influence of the parameters of the acoustic field and the regenerator’s structure on the thermoacoustic conversion is analyzed, and the optimum condition for the thermoacoustic conversion is discussed. The results are consistent with the qualitative analysis. Additionally, our theoretical results also show a good agreement with the experimental data [Biwa et al. Phys Rev E 2004;69(6):066304(6)], which indicates the validity of the analysis in this paper. Furthermore, the analysis in this paper further provides a more intensive understanding of these experimental results. The conclusions obtained in this paper are significant to guide for the design of new thermoacoustic devices.     

Ministry of Industry and Information Technology Confirmed 2014 Main Expected Targets for Energy-Saving and Comprehensive Utilization

Ministr y of Industr y and Information Technology confirmed that the main expected targets for energysaving and comprehensive utilization in 2014 are：energy consumption and CO2 emissions per unit of industrial added-value decreases by 4.5%,water consumption per ten thousand Yuan of industrial added-value decreases by7%,comprehensive utilization of industrial solid waste is further improved,and pollution emissions in key industries is markedly reduced.     

燃气系统重要件故障模式研究分析

燃气计量阀、减压器、低压截止阀是天然气发动机燃气系统中重要的专用件,市场反应D系列天然气发动机专用件报修事故高,为了降低其故障,通过对故障件的外观、基本测试和台架试验分析等,分析出根本原因,提出有效解决措施和管理对策,取得了一定成效.     

执行SO2和NOx新排放标准的压力及建议

通过对《火电厂大气污染物排放标准》(GB 13223-2011)污染限值的解读,结合目前燃煤电厂实施脱硫、脱硝工程的近况及实际运行的经验,叙述了燃煤电厂执行二氧化硫和氮氧化物新排放标准所面临的巨大压力,以及加大减排措施的力度、治污设备的技术改造、减排效率的提升等一系列问题.对新排放标准中重点地区二氧化硫的排放浓度小于50 mg/m3、氮氧化物的排放浓度小于100 mg/m3的限值要求进行了客观分析,提出了若干建议.     

碳足迹核算在纯棉坯布加工过程中的应用

文章研究了碳足迹的计算方法及其在织布厂的应用情况,分析了织布厂碳足迹计算的整体思路及产品生产过程中各设备的电能消耗,指出织布厂的碳排放量可通过计算电能消耗的间接方法求得,此方法是可行的。通过计算碳足迹,可以得到棉坯布在加工过程中各工序的碳排放量,为企业提供节能减排的有效路径与方法,对纺织企业节能减排具有现实的指导意义。     

Effect of Saccharomyces cerevisiae fermentation product on ruminal fermentation and nutrient utilization in dairy cows

The goal of this experiment was to investigate the effect of yeast culture (Saccharomyces cerevisiae) on rumen fermentation, nutrient utilization, and ammonia and methane emission from manure in dairy cows. Eight ruminally cannulated Holstein cows were allocated to 2 dietary treatments in a crossover design. Treatments were control (no yeast culture) and XP (yeast culture, fed at 56 g/head per day; XP, Diamond V Mills Inc., Cedar Rapids, IA). Dry matter intake, milk yield, milk composition, and body weight were similar between treatments. Milk urea nitrogen concentration was also not affected by treatment. Rumen pH was similar between the control and XP treatments, but rumen ammonia concentration tended to be lower with XP than with the control. Treatment had no effect on concentrations of total or individual volatile fatty acids, protozoal counts, polysaccharide-degrading activities (except amylase activity that tended to be increased by XP), or methane production in the rumen. Urinary N losses did not differ significantly between treatments, but allantoin and total purine derivative excretions and the estimated microbial N outflow from the rumen tended to be increased by XP compared with the control treatment. Total-tract apparent digestibility of dietary nutrients was not affected by XP. Milk fatty acid composition was also not altered by XP supplementation. Cumulative (253 h) ammonia and methane emissions from manure, measured in a steady-state gas emission system, were slightly decreased by XP. Overall, the yeast culture tested had little effect on ruminal fermentation, digestibility, or N losses, but tended to reduce rumen ammonia concentration and increase microbial protein synthesis in the rumen, and decreased ammonia and methane emissions from manure.     

1000MW机组锅炉氮氧化物排放影响的试验研究

基于现场燃烧调整试验方法,对某厂1台1000MW超超临界切圆燃烧锅炉NOx的排放特性及其影响因素进行了系统的分析。针对锅炉燃烧系统的运行特点,主要进行了氧量、负荷、燃尽风量(包括AA风和OFA风)、主燃烧区燃烧器风量和配风方式、磨煤机运行组合方式、燃烧器摆角、煤质等因素的试验研究。研究结果表明:对于具有先进低NOx燃烧系统的锅炉,其锅炉负荷、锅炉燃用的煤质、运行时氧量的变化和燃烧器喷口摆角及磨煤耗机组的运行方式都是锅炉NOx排放的影响因素,其中运行时氧量的变化对NOx排放影响最重,随着氧量的增加,锅炉NOx排放浓度呈线性增加。而在保持大量燃尽风实现空气分级燃烧的条件下,主燃烧区燃烧器风量和配风方式对NOx排放浓度的影响是微弱的。     

天津市两证合一地籍测量数据制图系统的设计及实现

两证合一地籍测量数据是天津市国土和房屋管理部门进行登记发证必须具备的要件之一,数据的制作较为复杂,作者根据实际需要开发出相应的数据制图系统,简化作图的流程。本文详细阐述了基于VBA技术,AE技术的两证合一地籍测量数据制图系统的设计开发及实现方法,并给出部分重要的程序代码。     

含碳捕集装置的电气综合能源系统低碳经济运行

面对当前电气综合能源系统在新能源消纳、低碳性方面存在不足的问题,在系统中引入碳捕集装置进行优化.首先通过弃风惩罚因子将弃风量转化为弃风成本,以系统运行成本与碳排放量为多目标建立一种含碳捕集的电气综合能源系统低碳经济运行模型,使用法线边界交叉法构造多目标问题的Pareto前沿,并利用模糊隶属度函数选择出综合满意度最大的解...     

中国食品工业“三废”与二氧化碳排放的相关性研究:基于1996～2008年间考察

基于全球低碳发展趋势,考察分析1996～2008年间中国食品工业"三废"排放与减排成效,并计算食品工业及分行业的二氧化碳排放,以此利用回归模型验证"三废"减排与碳减排的相关性。结果表明,我国食品工业的"三废"减排与碳减排显著相关,且提高固体废弃物的综合利用率较废水和废气的治理改善更可以显著降低食品工业碳排放。