Generating electricity while walking with loads

We have developed the suspended-load backpack, which converts mechanical energy from the vertical movement of carried loads (weighing 20 to 38 kilograms) to electricity during normal walking [generating up to 7.4 watts, or a 300-fold increase over previous shoe devices (20 milliwatts)]. Unexpectedly, little extra metabolic energy (as compared to that expended carrying a rigid backpack) is required during electricity generation. This is probably due to a compensatory change in gait or loading regime, which reduces the metabolic power required for walking. This electricity generation can help give field scientists, explorers, and disaster-relief workers freedom from the heavy weight of replacement batteries and thereby extend their ability to operate in remote areas.     

风光互补发电系统在转地饲养蜂场中的应用研究

在蜂群转地饲养中,由于场地条件的限制,蜂农的生产、生活难以获取现有交流市电的支持,经过实地蜂场调研,目前蜂农多数使用光伏组件收集太阳能作为能提供源。蜂农在户外难免遇到连续阴雨或者多云天气,无法为蓄电池充电,现有装置就无法满足蜂农的要求。针对这种现状,以风光互补发电系统作为切入点,针对转地饲养蜂农供电问题进行研究,将风力发电与太阳能发电结合起来,弥补连续阴雨天供电不可靠的缺陷,同时能够保证用户均衡充足的用电需求,为蜂农野外养蜂作业提供新的技术理论参考。     

Community digester operations and dairy farmer perspectives

Rising energy costs, increasing herd sizes, and other structural changes affecting the New York dairy industry may make farmers receptive to new energy production technologies. Anaerobic digestion represents a possible benefit to farmers by reducing odor while producing methane for electricity. However, current digester designs are for herd sizes of 300 or more cows, with significant economies of scale, so smaller operators may have little interest in the technology. Moreover, without a favorable policy environment and reliable grant programs, the initial investments required for digester installation might deter operators. One solution to these issues may be community digesters, which are centrally located facilities that accept manure from multiple farms. Data from a survey of New York dairy farmers were used to assess farmers’ interest in community digesters. In general, interest was associated with power generation outcomes and reservations about organic farming practices; advocates might encourage their use among smaller conventional farm operators looking for new sources of profit and diversification.     

Cubic AgPb(m)SbTe(2+m): bulk thermoelectric materials with high figure of merit

The conversion of heat to electricity by thermoelectric devices may play a key role in the future for energy production and utilization. However, in order to meet that role, more efficient thermoelectric materials are needed that are suitable for high-temperature applications. We show that the material system AgPb(m)SbTe(2+m) may be suitable for this purpose. With m = 10 and 18 and doped appropriately, n-type semiconductors can be produced that exhibit a high thermoelectric figure of merit material ZTmax of approximately 2.2 at 800 kelvin. In the temperature range 600 to 900 kelvin, the AgPb(m)SbTe(2+m) material is expected to outperform all reported bulk thermoelectrics, thereby earmarking it as a material system for potential use in efficient thermoelectric power generation from heat sources.     

Solar energy and electric utilities: should they be interfaced?

Analyses of the economics of solar collection in the firm- and shifting-peak cases (that is, with off-peak electricity indefinitely available or with a flat load curve) indicate that, for many important applications, solar energy systems that interface with electric utilities can be justified only in terms of the value of the off-peak utility fuels that they displace. In regions where off-peak electricity costs are low, the most economically efficient solar energy systems will be those that use electricity as the auxiliary energy source. This implies extremely low break-even costs for a number of important solar energy applications. In regions where the cost of off-peak electricity is higher than that of competing energy forms, the most economical solar energy systems will utilize auxiliary fuels other than electricity. The general conclusion is that conventional electric utility systems and most solar energy systems represent a poor technological match. The basic problem is that both technologies are very capital intensive. The electric utility, because of the high fixed costs of generation, transmission, and distribution capacity, represents a poor backup for solar energy systems. On the other hand, the solar collection system, because it represents pure, high-cost capital and because of its outage problems, cannot be considered as a part-load source of auxiliary energy for the electric utility system.     

农业环境因子低功耗干电池检测系统设计

 在农业领域上的检测设备由于测试环境的影响,无法通过市电供电。本文的目的是设计一套可通过干电池进行长时间供电的农业环境因子检测系统。文章中讨论了在低功耗状态下电路及软件的设计,并对系统的耗电进行了理论分析,最后一个温度和湿度的测试系统的测试结果表明系统耗电与理论分析一致,并满足实际工作的需求。     

青稞联合收获机配套秸秆打捆装置设计与试验

针对北方藏区传统青稞收获作业中秸秆收集运输机械化程度低、现有机具行走稳定性差的问题,设计一套青稞联合收获机配套秸秆打捆装置,整机主要由喂入机构、压缩机构和打结器离合装置组成,对样机关键部件进行选型设计,确定了打捆机各装置的配置方式与动力分配。应用ABAQUS软件对整机机架振动特性进行有限元仿真,对比固有频率与外部激励频率变化趋势,改进机架结构并优化其参数,以避免作业时发生共振。通过ADAMS软件得到喂入机构上、侧拨叉工作时的运动轨迹,确定两拨叉结构参数,以避免作业时出现干涉。田间试验结果表明:秸秆成捆率达到98.3%,草捆合格率达到94.7%,草捆抗摔率超过90%,整机作业效率达到0.7 hm²·h^-1,平均草捆截面尺寸达到0.5 m×0.6 m,平均草捆密度达到124 kg·m^-3,各项性能指标均达到设计要求。该研究可为青稞联合收获、秸秆打捆一体化作业机具的设计与研制提供应用实例和技术依据。     

小型甘薯收获机农艺配套措施试验

对福建省大面积推广应用的9个甘薯品种采用LG-4U-1A型甘薯小型收获机进行机械化收获试验,结果表明：LG-4U-1A型小型甘薯收获机最佳行走路线宜采用隔行收获,最佳行走速度为600 m/h,明薯率高达97％,埋薯率和伤薯率大大降低;作业效率是人工的20倍,收获成本仅为人工的1/16;试验的8个甘薯品种均适宜机械化收获.福建砂壤土类型的土壤,畦带沟宽90～ 100 cm的种植模式均能适宜该型甘薯小型收获机机械化收获.     

两步法高效沼气发电研究

阐述了SANYI两步产气发电系统，该系统可以达到稳定而高效的产沼气发电，可以作为稳定的并网能源设施，从而为开发高效稳定的产沼气发电工程提供参考。     

两步法高效沼气发电研究

阐述了SANYI两步产气发电系统,该系统可以达到稳定而高效的产沼气发电,可以作为稳定的并网能源设施,从而为开发高效稳定的产沼气发电工程提供参考。     

太阳能光伏发电系统在植物工厂中的应用初探

从降低植物工厂运行成本的角度出发,将太阳能光伏发电系统与植物工厂相结合,可将太阳能转变成电能后为植物工厂的运行提供能源。太阳能技术的应用,将有望降低植物工厂的运行能耗,减少植物生产对常规能源的依附。     

手扶拖拉机组制动性能的试验研究

通过对手扶拖拉机组制动初速度、载重量、制动力矩和道路等因子的试验和分析，得出影响机组制动性能的各因子定量数学表达式．     

生物质发电供应链协同演化研究——基于山东省生物质发电厂的实证研究

为探索生物质发电供应链系统协同演化规律,促进生物质发电产业发展,基于"农户-中间商-电厂"燃料供应模式,分析生物质发电供应链系统的协同特性,建立生物质发电供应链系统协同学模型,并对山东省S生物质发电供应链系统进行实证研究。结果表明:农户秸秆售卖价格是主导S生物质发电供应链系统协同演化的序参量;生物质发电转化率对供应链系统协同演化有重要推动作用;目前新政策可以有效促进供应链系统进入更高阶协同。     

自保护式波浪发电装置控制系统研究

首先介绍了一种双蓄能器交替工作的波浪发电装置的构成和工作原理,设计了基于AVR单片机的波浪发电控制系统的硬件模块和控制软件。该控制系统通过对海况行监测,控制双液压缸与蓄能器工作切换,调节油路上阀门开关,实现双蓄能器交替充放油,驱动液压马达连续运转,并在恶劣海况时停机自保护。通过水池样机试验表明,该波浪发电控制系统实现波浪能平稳地转化为电能输出,发电输出误差在10％内,探索发电装置与海况匹配关系,为实现海上发电装置高效稳定发电奠定基础。     

国内外海洋能发电测试场研究现状

海洋能作为一种重要的海洋资源和清洁能源,其开发和利用是国家发展战略的必然要求。海洋能发电测试场能对海洋能装置进行实海况并网试验,是海洋能装置从工程样机走向规模产业化应用的关键环节。介绍了目前国外大型的波浪能、潮流能测试场的建设与运行情况,并做了简要的对比分析;还介绍了当前我国在海洋能试验与测试场建设方面的进展、现状及相关技术。探讨了我国海洋能发电进行并网测试的必要性,指出建设海洋能发电测试场是保证我国海洋能资源的有效利用途径。     

高速收割机的试验研究(Ⅰ)——高速收割机的方案设计与评价

在一组约束条件下，采用新型齿形链式切割器及同轴驱动方式，运用综合评判理论，设计并论证了高速收割机的总体方案。论证表明，总体方案设计合理，既可高速作业，又可宽幅收割，实现了高速切割与高速前进、高速收获与高速输送的有机结合和有效匹配，结构简单，噪音小，生产率高。     

General Nexus Between Water and Electricity Use and Its Implication for Urban Agricultural Sustainability: A Case Study of Shenzhen,South China

Although water and energy resources are well-recognized concerns regarding economic and social development sustainability, little specific research has focused on both water and energy problems at the same time. This study analyzed the water and electricity-use patterns in Shenzhen, South China during 2001-2009. A curve regression method was used to examine the relationship between water and electricity use per gross domestic product (GDP) in Shenzhen and its three sectors, i.e., agriculture, industry & construction, and residential life & services. Results showed that agriculture only covered less than 10% of water and electricity use in Shenzhen, while industry & construction and residential life & services accounted for more than 90% of water and electricity use in Shenzhen, which coincided with the city's industrial structure. The water and electricity use per GDP in agriculture was the biggest among three sectors in Shenzhen during 2001-2009, which means inefficiency of water and electricity use in agriculture. Due to transitioning to advanced materials and manufacturing, both water and electricity use per GDP in industry & construction decreased during 2001-2009 and their utilization efficiencies gradually increased over time. The same held true for those in residential life & services transformed toward modern business, creative culture, finance services, etc. Derived from the survival of the fittest in competing for limited water and electricity resources, agriculture in Shenzhen has been gradually substituted by industry & construction and residential life & services, with much higher efficiencies of water and electricity use. And traditional agriculture will not be sustainable in the process of urbanization and industrialization, except high-tech intensive agriculture with low water and energy cost. Furthermore, by means of curve regression, we found that there was a significant quadratic relationship between water use per GDP and electricity use per GDP in the entire city and its three sectors. Suitable industrial transformation and advancement was a very effective way to save water and energy for modern cities. This can provide some reference for systematic planning and design of water and electricity allocation and use in agriculture, industry & construction and residential life & services in a city.     

番茄收获机割台特点及发展现状

通过对国内外番茄收获机割台上的分苗装置、切割装置、辅助切割装置与辅助输送装置等关键装置结构与性能的分析,综述了番茄收获机割台的特点及其发展现状,并对割台各装置的设计提出了建议,为番茄收获机国产化提供了一定的参考依据。     

小型玉米秸秆收割机的仿真与试验

针对甘肃地区玉米种植地块小且分散,人工收获劳动强度大,生产率低等问题,设计并研制了一种由传动系统、切割装置、扶禾器等组成的小型玉米秸秆收割机。利用Solid Works和ADMAS对整机进行虚拟仿真,得到收割机的性能指标,并对样机进行田间收割试验。结果表明:收割机切割装置转轴的总动能为1.547×105 J,转轴的总冲量为3 858 N·s;在不清除地膜和杂草的条件下,平均割茬高度为1.76 cm,玉米秸秆的平均铺放合格率达95.59%,各装置协调、平稳、可靠,平均工作效率可达5.10 hm2/h。通过整机虚拟仿真得到的转轴动能和冲量可作为收割机切割效果的性能指标。     

转地养蜂专业户光伏系统的研究

[目的]改善养蜂人员的工作条件,推广可再生能源的利用。[方法]用光伏系统为养蜂人员供电,结合转地养蜂的特点对光伏系统进行研究,设计光伏系统的关键部件,改善转地养蜂人员的用电电源质量。[结果]利用所设计的转地养蜂太阳能光伏系统为养蜂人员供电,降低了光伏系统的成本,改变了光伏系统的结构,特别是减小了光伏系统的重量,使系统便于转地运输和安装。[结论]用所设计的光伏系统供电,提高了养蜂的科技含量,改善了养蜂人员的电源供应情况,也推广了可再生能源的利用。