共查询到20条相似文献，搜索用时 265 毫秒
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根据我国北方冬季气温偏低、沼气池产气慢且少的特点,结合日照特点,设计了由太阳能温室和集热室两部分组成的太阳能双效增温沼气系统。利用传热学的基本理论,建立了沼气系统的热平衡方程,并通过理论计算,分析了太阳能双效增温沼气系统内各部分的热利用效率。 相似文献
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我国北方高寒地区气温较低,特别在冬季,温度是影响厌氧发酵微生物的活性、制约沼气发酵的重要因素,也是限制在高寒地区发展建设大型沼气工程的关键问题。为解决这一问题,提出了利用太阳能与生物质锅炉联合为厌氧发酵系统加热增温的新思路,并以依安县依龙镇丰林村大型沼气工程为研究对象,利用力控组态软件随时监测和采集反应器正常运行情况下加热系统的数据。同时,对当地最冷月份1月的运行数据进行了分析,结果表明:在正常工作条件下,该系统可以保证大型沼气反应器冬季的正常产气,对北方高寒地区发展大型沼气工程具有重要的指导意义。 相似文献
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为了解决南方地区阴雨天和广大北方地区冬季沼气发酵温度低、产气效率低等问题,本文尝试设计以太阳能集热、空气源热泵、电加热并联的沼气发酵增温系统.这三种加热技术互补使用可满足不同天气条件下沼气发酵的增温需求.太阳能集热器作为增温系统的主要加热装置.当太阳辐射不能满足温度需求时,使用空气能热泵加热.特殊情况下使用电加热装置增温.为满足恒温发酵,该系统配备了以单片机为核心的自动控制器,分别包括温度检测电路单元、温控电路单元、键盘输入单元、显示单元和报警单元.该增温系统实现了沼气池恒温发酵功能,能够在阴雨天和冬季稳定增温,有效的提高沼气池产气效率,减少能源消耗和人员参与. 相似文献
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我国北方农村地区,户用沼气池多为常温发酵,发酵温度偏低,尤其在冬季气温较低时,多数沼气池无法正常使用甚至停用,造成资源的较大浪费,同时也降低了农户使用和建造沼气池的积极性。为了消除环境温度对沼气池的影响,提高沼气池产气率,笔者将沼气池与太阳能集热系统相结合,设计出一款适用于北方寒冷地区的高效太阳能户用沼气池,有效提高了沼气池的发酵温度,解决了北方寒冷地区沼气池冬季无法正常使用的问题。 相似文献
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不同措施对户用沼气池内温度及产气量的影响 总被引：1，自引：0，他引：1
如何提高北方农村户用沼气池冬季产气量,是当前中国北方沼气技术人员及沼气池用户面临的主要问题,在山东省章丘市建设了18口10 m3的地下式户用沼气池,研究采取不同保温升温措施对户用沼气池池内料液温度及沼气产量的影响。结果表明,在山东地区,冬季平均气温0℃左右(最低达到-11.2℃,而最高为11.8℃,)且气温变化幅度比较大的情况下,户用沼气池采用池体深埋、秸秆保温、保温材料、加盖暖棚和太阳能等技术对沼气池温度影响比较大,池温分别高于对照池3.7℃,4.3℃,4.9℃,5.4℃和5.5℃,日均产气量分别提高0.19 m3,0.24 m3,0.32 m3,0.40 m3和0.41 m3。产气量与外界气温和沼气池低温呈显著正相关系(P0.01),因此,冬季沼气池的最低温度是决定产气量的主要因素。为了提高冬季产气量,应该从提高沼气池低温这个参数入手进行调整。 相似文献
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Overland water and salt flows in a set of rice paddies 总被引：1，自引：0，他引：1
E. Playn O. Prez-Coveta A. Martínez-Cob J. Herrero P. García-Navarro B. Latorre P. Brufau J. Garcs 《Agricultural Water Management》2008,95(6):645-658
Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m−1) and an infiltration rate of 5.8 mm day−1. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day−1), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day−1 was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration. 相似文献
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车用发动机润滑油失效规律与更换周期研究 总被引：7，自引：0，他引：7
研究在正常使用条件下１０Ｗ／３０－ＱＣ级润滑油用于某型车用发动机时所表现的失效规律,确认期服从两参数Ｗｅｉｂｕｌｌ分布,并给出分布的尺度参数η和形状参数ｍ之最佳线性无偏估计（ＢＬＵＥ）同时,还为定量分析,计算车用发动机润滑油的使用可靠性和合理确定其更换周期提供了一套可供借鉴的方法,并给出了具体的计算实例。 相似文献
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赵国杰 《农业机械化与电气化》2011,(4):106-107
乡（镇）农技推广体系是农业发展的关键。介绍朝阳市农业技术推广体系的现状,针对目前体制及运行机制、服务手段等方面存在的问题,提出适合朝阳市乡（镇）农技推广体系改革与发展的对策,以期对全省农技推广体系改革和发展起到一些借鉴作用。 相似文献
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苑庆刚 《农业机械化与电气化》2010,(3):52-54
草莓果味酸甜爽口,营养价值高,为人们所喜爱的应市鲜果之一。由于草莓易受损伤和微生物侵染,因此其采收、贮藏过程极为重要。介绍草莓采收过程中的注意事项以及11种贮藏保鲜技术的实施步骤和操作方法,推介9种加工方式,为草莓产业化提供技术支持。 相似文献
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对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。 相似文献
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对《种子法》存在问题的探讨 总被引：1，自引：0，他引：1
李鹏 《农业机械化与电气化》2011,(6):129-130
《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。 相似文献
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瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。 相似文献
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在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。 相似文献
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About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered. 相似文献