共查询到19条相似文献，搜索用时 125 毫秒
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对平房仓储藏的早籼稻谷采用移动式环流装置结合横向通风系统进行膜下横向环流熏蒸,探究平房仓环流熏蒸在横向通风系统中的技术特点、操作工艺和应用效果。试验表明,利用横向通风系统可使PH3气体在结束环流施药后3h内,达到最低与最高浓度比0.6的要求,可以在粮堆内快速而均匀地形成有效浓度,大幅减轻劳动强度,增强熏蒸效果和应急情况的处理。 相似文献
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为了研究平房仓横向通风技术在玉米储藏上的应用效果,明确玉米储藏过程横向通风工艺及其参数,利用高大平房仓中设计安装的横向通风设施,以及在储藏玉米粮堆中预埋的插入式毕托管,对高大平房仓横向通风系统进行实仓测试。全面开展了玉米储藏过程中横向通风工艺应用研究,测试了在横向通风系统通风时,风速、风量、系统各部分阻力和粮堆压力分布。研究发现,在储藏玉米的高大平房仓中应用横向通风系统时,粮堆单位粮层阻力较小,在实用单位通风量时,横向通风系统总阻力不大于1200Pa;同时横向通风还具有风量分配均匀、粮堆通风均匀性良好的特点。该研究为玉米在配备横向通风系统的高大平房仓储藏提供了技术支持。 相似文献
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在配备合理的通风环流系统的高大平房仓中进行PH3无二氧化碳环流熏蒸，能使气体在粮堆内分布均匀，取得良好的杀虫效果，具有安全性、经济性等特点。 相似文献
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刘金顺 《粮油仓储科技通讯》2007,(3):26-27
在高大平房仓粮面下40cm处合理布设UPVC通风管道，通过轴流风机上吸式通风。在密闭的高大平房仓中进行膜下通风和环流熏蒸，该通风、熏蒸系统大大地减轻了保化人员的劳动强度，并具有能耗低、降温均衡、不易返弹，熏蒸杀虫用药量少、无死角的特点。 相似文献
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利用高大平房仓原有的通风系统、熏蒸环流系统和新装备的PSA变压吸附制氮系统,对本库1号仓、4号仓、8号仓、13号仓储藏的玉米分别采取通风口充气粮面排气的充—排—充—排—充工艺、粮面充气通风口排气的边充边排工艺、粮面充气通风口排气的充—排—充工艺、利用径向通风系统横向压入并横向吸出的边充边排工艺进行充氮储粮试验,通过试验比对,粮面充气通风口排气边充边排工艺和利用径向通风系统横向压入并横向吸出的边充边排工艺比其它二种充氮降氧方法速度快,粮堆氮气浓度分布均匀,杀虫效果好,能耗低,费用省,操作简便,具有良好的推广应用前景。 相似文献
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在高大平房仓采用粮面施药、通风孔施药及粮面与通风孔施药3种方式，进行磷化铝动态潮解环流熏蒸，第一次连续环流48小时，以后每天环流3小时，取得了良好的杀虫效果。 相似文献
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在保温性能非常差的简易平房仓进行大豆低温储藏度夏试验。针对简易平房仓保温性能差,热量容易进入粮堆的特点,选择适当的天气,开启通风、环流一体化系统可以将热量排出仓外,再通过地下冷源二次降温,仅环流4 d,试验仓最高粮温降到20℃以下,实现了大豆低温安全储藏。试验仓度夏期间,大豆品质良好。 相似文献
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《Netherlands Journal of Sea Research》1989,23(3):239-253
In the partially mixed part of the Volkerak Estuary current speed and salt concentration are measured in several stations for periods of 13 hours on August 16 and 17, 1977. The freshwater discharge on those days and during the preceding six months is kept constant at a rate of 50 m3·s−1. In spite of different wind conditions, the longitudunal distribution of the tidally- and cross-sectionally averaged salt concentration is the same for both days. The vertical structure of circulation and salt concentration differ significantly. A similar set of measurements is carried out on March 18, 1980 with a constant freshwater discharge of 100 m3·s−1. The doubling of freshwater discharge leads to a relatively small increase in vertical circulation and stratification.In this study, the vertical circulation and stratification is examined in terms of the external forcings, freshwater discharge and wind, with special emphasis on wind. Tide conditions, for the three measurement days are similar. The estuary is schematized to a prismatic channel with a rectangular cross-section. In the schematized channel the tidally averaged salt concentration and velocity distribution are laterally uniform. To account for salt fluxes in the actual estuary associated with lateral and time-variations in current velocity and salt concentration, a diffusive salt flux is introduced. The effect of wind and longitudinal density gradients on the vertical circulation and stratification in the schematized channel is investigated using a simplified form of the two-dimensional conservation of momentum and salt equations. Using observed values along the axis of the estuary a scaling analysis shows that in the two-dimensional conservation of momentum equation the longitudinal pressure gradient and horizontal turbulent shear are the dominant terms, closely followed by the tidal stress. In the conservation of salt equation, the dominant terms are those associated with advective fluxes resulting from the horizontal and vertical tidal mean velocities, a horizontal flux associated with tidal variations in the longitudinal velocity and salt concentration and the vertical turbulent flux. Retaining only first order terms, the equations are solved using the similarity solution of Hansen and Rattray. Comparing calculated and observed vertical circulation and stratification it is shown that wind mixing significantly increases the vertical exchange of momentum, thereby reducing the density-driven vertical circulation (=gravitational circulation) and stratification. At the same time, through the wind surface stress, wind generates its own vertical circulation and, therefore, stratification. An expected increase in vertical exchange of mass with increasing wind speed and accompanying reduction in stratification could not be confirmed by the analysis. It is concluded that on the days of the measurements wind is as important as the longitudinal salt concentration gradient in forcing vertical circulation and stratification. Care should be taken in generalizing this conclusion as on the days of the measurements the axial component of the wind velocity is always in the down estuary direction. 相似文献
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在高大平房仓中选用空调控温、内环流控温储粮技术进行控温试验。通过对比分析温度变化情况得出,内环流控温能达到控温储粮目的,可实现低温/准低温储粮,且能耗少、费用低。 相似文献
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Energy Boom and Gloom? Local Effects of Oil and Natural Gas Drilling on Subjective Well‐Being 
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下载免费PDF全文 Prior to the precipitous drop in oil prices in 2014, the U.S. had experienced a substantial increase in oil and natural gas extraction due to technological advancements including horizontal drilling and hydraulic fracturing. This increased energy development likely created both benefits and costs, but the net effects for local residents are not well understood. This paper examines the effects of conventional and horizontal oil and natural gas drilling in Texas on subjective assessments of life‐satisfaction and bad mental health days for nearby residents. Horizontal drilling has statistically significant deleterious effects on well‐being, but the effects are driven by the Dallas‐Fort Worth (DFW) metropolitan area, an area with both very high levels of horizontal drilling and a large urban population. 相似文献
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《Netherlands Journal of Sea Research》1995,33(3-4):271-299
The rationale is given of how the gross physical features of the circulation and the stratification of the North Sea have been aggregated for inclusion in the ecosystem box model ERSEM. As the ecosystem dynamics are to a large extent determined by small-scale physical events, the ecosystem model is forced with the circulation of a specific year rather than using the long-term mean circulation field. Especially the vertical exchange processes have been explicitly included, because the primary production strongly depends on them. Simulations with a general circulation model (GCM), forced by three-hourly meteorological fields, have been utilized to derive daily horizontal transport values driving ERSEM on boxes of sizes of a few 100 km. The daily vertical transports across a fixed 30-m interface provide the necessary short-term event character of the vertical exchange.For the years 1988 and 1989 the properties of the hydrodynamic flow fields are presented in terms of trajectories of the flow, thermocline depths, of water budgets, flushing times and diffusion rates. The results of the standard simulation with ERSEM show that the daily variability of the circulation, being smoothed by the box integration procedure, is transferred to the chemical and biological state variables to a very limited degree only. 相似文献
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ABSTRACT Existing analyses of electricity deregulation have focused on situations where horizontal market power is present. This paper instead evaluates a market where a competitive outcome is more likely. Competitive market supply and demand curves for electricity have been simulated for a twenty‐state region. These simulated supply and demand curves are used to predict short‐run and long‐run prices for electric power. Many consumers will see a drop in the portion of their electric bills accounted for by the current economic costs of supplying them with electricity. Adjustments to consumers’ bills for stranded cost recovery will be determined by legislators and regulators on a state‐by‐state and utility‐by‐utility basis. Because of excess capacity that currently exists in the industry, the decline in prices will be greater in the short run than in the long run. 相似文献
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《Netherlands Journal of Sea Research》1990,25(1-2):31-44
Data, gathered in the North Sea some 60 km north of the Netherlands, are used to describe the regional dynamics at sub-tidal frequencies. Using a tidally averaged set of the vertically averaged horizontal momentum equations, the influence of the separate terms in these equations is investigated experimentally. The results reveal that, especially further offshore, the wind driven motion is in (near) geostrophic balance. This confirms the ability to monitor the circulation, using information on the wind field and the bottom pressure distribution, within an accuracy equivalent to an accuracy of 0.5 mb of low pass filtered bottom pressure gauge measurements.In a part of the area where the bottom topography reaches a slope of 1.2×10−3 and where density fronts are observed, the motion is frequently found out of geostrophic balance. The apparent imbalance can partly be attributed to ‘sub-grid’ horizontal density gradients, which are incorporated in the measured bottom pressure gradients, assuming that no sea-level adjustment occurs. 相似文献