Triton's Global Heat Budget

Internal heat flow from radioactive decay in Triton's interior along with absorbed thermal energy from Neptune total 5 to 20 percent of the insolation absorbed by Triton, thus comprising a significant fraction of Triton's surface energy balance. These additional energy inputs can raise Triton's surface temperature between approximately 0.5 and 1.5 K above that possible with absorbed sunlight alone, resulting in an increase of about a factor of approximately 1.5 to 2.5 in Triton's basal atmospheric pressure. If Triton's internal heat flow is concentrated in some areas, as is likely, local effects such as enhanced sublimation with subsequent modification of albedo could be quite large. Furthermore, indications of recent global albedo change on Triton suggest that Triton's surface temperature and pressure may not now be in steady state, further suggesting that atmospheric pressure on Triton was as much as ten times higher in the recent past.     

The Phase Composition of Triton's Polar Caps

Triton's polar caps are modeled as permanent nitrogen deposits hundreds of meters thick. Complex temperature variations on Triton's surface induce reversible transitions between the cubic and hexagonal phases of solid nitrogen, often with two coexisting propagating transition fronts. Subsurface temperature distributions are calculated using a two-dimensional thermal model with phase changes. The phase changes fracture the upper nitrogen layer, increasing its reflectivity and thus offering an explanation for the surprisingly high southern polar cap albedo (approximately 0.8) seen during the Voyager 2 flyby. The model has other implications for the phase transition phenomena on Triton, such as a plausible mechanism for the origin of geyser-like plume vent areas and a mechanism of energy transport toward them.     

The voyager 2 encounter with the neptunian system

An overview of the Voyager 2 encounter with Neptune is presented, including a brief discussion of the trajectory, the planned observations, and highlights of the results described in the 11 companion papers. Neptune's blue atmosphere has storm systems reminiscent of those in Jupiter's atmosphere. An optically thin methane ice cloud exists near the 1.5-bar pressure level, and an optically thick cloud exists below 3 bars. Neptune's magnetic field is highly tilted and offset from the planet's center; it rotates with a period of 16.11 hours. Two narrow and two broad rings circle the planet; the outermost of these rings has three optically thicker arc segments. Six new moons were discovered in circular prograde orbits, all well inside Triton's retrograde orbit. Triton has a highly reflective and geologically young surface, a thin nitrogen atmosphere, and at least two active geyser-like plumes.     

Subsurface energy storage and transport for solar-powered geysers on triton

The location of active geyser-like eruptions and related features close to the current subsolar latitude on Triton suggests a solar energy source for these phenomena. Solidstate greenhouse calculations have shown that sunlight can generate substantially elevated subsurface temperatures. A variety of models for the storage of solar energy in a sub-greenhouse layer and for the supply of gas and energy to a geyser are examined. "Leaky greenhouse" models with only vertical gas transport are inconsistent with the observed upper limit on geyser radius of approximately 1.5 kilometers. However, lateral transport of energy by gas flow in a porous N(2) layer with a block size on the order of a meter can supply the required amount of gas to a source region approximately 1 kilometer in radius. The decline of gas output to steady state may occur over a period comparable with the inferred active geyser lifetime of five Earth years. The required subsurface permeability may be maintained by thermal fracturing of the residual N2 polar cap. A lower limit on geyser source radius of approximately 50 to 100 meters predicted by a theory of negatively buoyant jets is not readily attained.     

Triton's Plumes: The Dust Devil Hypothesis

Triton's plumes are narrow columns 10 kilometers in height, with tails extending horizontally for distances over 100 kilometers. This structure suggests that the plumes are an atmospheric rather than a surface phenomenon. The closest terrestrial analogs may be dust devils, which are atmospheric vortices originating in the unstable layer close to the ground. Since Triton has such a low surface pressure, extremely unstable layers could develop during the day. Patches of unfrosted ground near the subsolar point could act as sites for dust devil formation because they heat up relative to the surrounding nitrogen frost. The resulting convection would warm the atmosphere to temperatures of 48 kelvin or higher, as observed by the Voyager radio science team. Assuming that velocity scales as the square root of temperature difference times the height of the mixed layer, a velocity of 20 meters per second is derived for the strongest dust devils on Triton. Winds of this speed could raise particles provided they are a factor of 103 to 104 less cohesive than those on Earth.     

Triton's Geyser-Like Plumes: Discovery and Basic Characterization

At least four active geyser-like eruptions were discovered in Voyager 2 images of Triton, Neptune's large satellite. The two best documented eruptions occur as columns of dark material rising to an altitude of about 8 kilometers where dark clouds of material are left suspended to drift downwind over 100 kilometers. The radii of the rising columns appear to be in the range of several tens of meters to a kilometer. One model for the mechanism to drive the plumes involves heating of nitrogen ice in a subsurface greenhouse environment; nitrogen gas pressurized by the solar heating explosively vents to the surface carrying clouds of ice and dark partides into the atmosphere. A temperature increase of less than 4 kelvins above the ambient surface value of 38 +/- 3 kelvins is more than adequate to drive the plumes to an 8-kilometer altitude. The mass flux in the trailing clouds is estimated to consist of up to 10 kilograms of fine dark particles per second or twice as much nitrogen ice and perhaps several hundred or more kilograms of nitrogen gas per second. Each eruption may last a year or more, during which on the order of a tenth of a cubic kilometer of ice is sublimed.     

日光温室冬季加温热负荷的计算和热风炉补温试验验证

【目的】研究日光温室冬季补温热负荷以及相应加温设备配套功率选型的准确性,计算日光温室冬季能耗的热损失,研究温室专用热风炉补温设备与理论计算能耗一致性问题。【方法】分析温室的总体热损失,研究各个围护结构的热工性能,取值计算温室总热损失量,分别计算出温室围护结构热损失、冷风渗透热损失以及温室内地面热损失占温室总散失热量的比例。【结果】温室理论计算单位面积能耗为166 W/(m²·h);单位面积能耗为142 W/(m²·h),二者基本趋于一致。【结论】各个围护结构的热工值取值合理,温室加温设备配套功率选型较为准确。温室加温热负荷计算时,不应考虑白天温室获得的太阳辐射热量,应将温室夜间最低温度时刻和极端灾害气候下温室需要补充满足的热量作为温室的加温热负荷值。     

Computer simulation of heating requirement and evaluation of the effects of permanent and movable external thermal insulations on energy conservation in greenhouses

The accurate determination of greenhouse heating requirements under varied weather and operating conditions is an important management problem. To minimize heat losses during heating and heat gain during cooling, and also to enhance solar energy utilization in greenhouses, various energy conservation measures are currently being applied in greenhouse construction and operation. In this study, a method of simulating heating requirements in greenhouses is presented, and the method was used to evaluate the effects of permanent and movable external thermal insulations on heating requirements on energy conservation in ten new and conventional greenhouse designs. A greenhouse heating requirement (heat loss) computer simulation model was developed by using basic energy conservation and heat transfer principles. The computer model was used to simulate energy consumption in the ten greenhouses and a test greenhouse designed and built at the University of Saskatchewan, Saskatoon, Sask., Canada. The effectiveness of applied thermal insulations was found to be a strong function of outdoor temperatures and day-length for a given location. The computer model can be used to estimate greenhouse heating requirements under varied operating and weather conditions in any given location.     

日光温室墙体一维导热的MATLAB模拟与热流分析

为探明日光温室墙体层间温度变化及热量传递动态规律,采用有限差分法建立墙体一维非稳态导热模型,利用MATLAB编制相应的模拟程序,计算出日光温室墙体各点的温度和热流。结果表明:该模型能够比较准确模拟日光温室土墙的温度。墙体内侧存在有效蓄热层,它对日光温室室内热环境有积极的作用。墙体有效蓄热层的热流白天指向墙体外侧,夜间指向墙体内侧,因此它的厚度直接根据热流的方向确定。有效蓄热层与天气、墙体总厚度以及墙体热特性参数有关。2012-12—2013-01期间有效蓄热层厚度为0.26~0.45m不等,最大值出现在连续雪天。同时从理论上验证了3.0m厚的温室土墙内部存在热流相对稳定的"热稳定层"。     

滇中高原双层塑料薄膜温室保温性能测试分析

 由于滇中地区典型单栋塑料温室存在保温性能不足的缺点,该试验同时对双层薄膜覆盖、单层薄膜覆盖和室外3种情况的最低温度进行了对比测试,对双层非充气塑料薄膜在该类温室中的保温效果进行了分析。结果表明:采用双层非冲气塑料薄膜,即在现有普通大棚内加设一层薄膜（间距20～30 cm）,在温室无遮挡,光照条件正常的情况下,冬季一月份前后室内最低平均气温可达5.37 ℃,比单层薄膜温室提高5.68 ℃,比室外提高3.25 ℃,保温效果显著。     

太阳能-水源热泵联合加热温室系统研究

为了探索太阳能-水源热泵技术在设施农业领域的应用方法和发展潜力,寻求解决温室加温费用高、存在污染等问题的方法,对一种用于温室的太阳能和水源热泵联合加温系统进行了试验研究。结果表明:此项研究对太阳能-水源热泵这项新能源技术在农业领域的应用具有重要的意义,可减少连栋温室水源热泵加温系统一次性投资和运行成本,降低能源消耗,为太阳能水源热泵联合作为温室有效的加温系统提供了一定的理论依据。     

农田生态系统的热通量变化和农田小气候分析

观测分析结果表明,上午棉田比稻田波文比大,下午稻田比棉田波文比大。白天稻田和棉田的显热通量为正值,晚上为负值。上午稻田显热通量大于棉田,下午则棉田大于稻田。稻田潜热通量全天大于棉田。棉田和稻田气温上午随时间增加而迅速升高,下午则随时间增加而气温下降。白天稻田内活动层随着高度升高气温增高,为辐射型;50cm以上随着高度升高而气温降低,为日射型;棉田与稻田相反。稻田相对湿度不同层次以早晨最高,内活动层以16：00最低,外活动层以13：00最低。在一天中大多数时间,稻田中风速大于棉田。     

结露对双层塑料薄膜温室保温性能的影响测试分析

 结露现象在温室中普遍存在，该试验通过对双层薄膜温室内自然结露和人工结露两种情况的室内最低温度同室外进行对比测试，对结露时间早晚对双层非充气塑料薄膜保温效果的影响进行了分析。结果表明：（1）结露对双层塑料薄膜保温性能存在不利的影响，结露时间早，温室内最低温度比结露时间晚时有所低，但幅度不大。（2） 双层塑料薄膜的保温性能与夹层内空气的相对湿度有关，空气相对湿度增大时，保温性能降低。     

The impact cratering record on triton

Impact craters on Triton are scarce owing to the relatively recent resurfacing by icy melts. The most heavily cratered surface has a crater density about the same as the lunar maria. The transition diameter from simple to complex craters occurs at a diameter of about 11 kilometers, and the depth-diameter relationship is similar to that of other icy satellites when gravity is taken into account. The crater size-frequency distribution has a differential -3 slope (cumulative -2 slope) and is the same as that for the fresh crater population on Miranda. The most heavily cratered region is on the leading hemisphere in Triton's orbit. Triton may have a leading-trailing asymmetry in its crater population. Based primarily on the similarity of size distributions on Triton and Miranda and the relatively young surface on Triton, the source of Triton's craters is probably comets. The very peculiar size distribution of sharp craters on the "cantaloupe" terrain and other evidence suggests they are volcanic explosion craters.     

锯缘青蟹(Scylla serrata)越冬日光温室的热环境模拟研究

提高浅海滩涂开发的科技含量是当前海洋开发中的重要课题之一.日光温室被称为"具有中国特色的设施园艺",由于其具有良好的保温、节能效果,被广泛应用于北方地区的蔬菜和花卉生产.已有多位学者对其作过光、热环境及建筑结构等的试验和理论研究,并进行了优化,将它用于水产品的越冬养殖是日光温室发展中的又一新领域.影响日光温室热环境的主要因素有:太阳辐射、风速、气温、相对湿度等.附带水池的日光温室中的水有较强的蓄热能力,其热环境有别于种植温室;另一方面日光温室具有保温性,其内的水池又有别于天然水池.根据有关试验的结果,并借鉴前人关于种植温室和天然水池的结论,本文建立了用于锯缘青蟹越冬的日光温室的热环境数学模型.经试验验证,该模型的计算值与实测值吻合较好,对水产品的越冬管理具有重要意义.     

基于有限元分析的日光温室土质墙体温度场模拟与验证

研究日光温室墙体中温度梯度及其变化规律对于日光温室墙体的蓄热保温性能分析评价、设计与建造有着重要的意义。2012年12月至2013年2月,采用自制多点温度测试仪,对山东泰安地区日光温室土质墙体的温度进行采集,并与ANSYS有限元模拟结果进行比较,发现温度场实测结果与模拟结果相吻合。进一步模拟结果表明,墙体蓄热/放热层一天中呈周期性变化,保温隔热层随外界温度变化较小,墙体下部温度较高,且在水平方向上温度梯度变化较小,在10~14℃持续时间长且稳定;距墙体内表面0.2 m处温度最高,并沿墙体厚度方向逐渐平缓降低,墙体外表面温度最低。基于模拟结果,对山东省泰安地区日光温室土质墙体进行结构优化,其最小厚度应为2.2 m,蓄热/放热层为0~0.5 m,保温隔热层为1.3~1.7 m。     

能源转移设计在农业大棚中的应用(英文)

通过在新型转移能源设计方面的研究应用,开发了一种新型转移能源农业大棚,建造了面积为180 m2的新型转移能源生态农业大棚示范工程试验房。该试验房采用复合太阳能电池板、废弃物为原料的无机泡沫保温材料作为农业大棚建造材料,应用空气-地源热泵互补蓄能系统,使能源采集和农业大棚一体化,达到零能源消耗的目的。该研究内容符合国家发展战略,具有巨大的经济效益和社会效益。     

温室太阳能与空气源热泵联合加温系统的试验

为了探索太阳能、空气源热泵技术在设施农业领域的应用方法和发展潜力,寻求解决温室加温费用高、存在污染等问题的方法,对一种用于温室的太阳能和空气源热泵联合加温系统进行了实验研究,介绍了系统的总体设计和试验方法,并在昆明地区对系统性能和温室加温效果进行了实验。结果表明：在昆明地区最冷月1月,蓄热水箱平均水温可达41.1℃,空气源热泵运行时,制热系数COP平均值均在3以上。无论晴天还是阴天,温室都能够满足作物生长需求。为太阳能空气源热泵联合作为温室有效的加温系统提供了一定的理论依据。     

低能耗日光温室建筑空间形态特征参数的取值原则

【目的】建造低能耗日光温室,提高日光温室冬季反季节蔬菜作物生产太阳能被动利用率、降低温室供热需求。【方法】基于建筑热工设计理论和建筑能耗模拟,研究日光温室建筑空间形态特征参数对温室光热环境营造的影响规律,并结合日光温室建筑构造特点,以及反季节蔬菜作物生产过程的光热环境需求特点,给出低能耗日光温室建筑空间形态特征参数的设计条件。【结果】同一地区日光温室高跨比不受跨度变化的影响,只与当地室外空气温度以及太阳辐射强度的变化相关;大暑日至翌年小满日期间,后屋面水平投影长度不应影响日光温室后排蔬菜作物接收太阳光照;确保冬至日至大寒日期间北墙可接收太阳光照射,对冬季反季节蔬菜作物生产期及日光温室高效利用太阳能具有重要的影响。【结论】基于该取值原则优化设计的温室,较北京地区现行常见温室需要提供的累积补充供热量减少15.7%,节能效果明显,为低能耗日光温室优化设计提供重要设计依据和方法参考。     

Solar Availability for Winter Space Heating: An Analysis of SOLMET Data, 1953 to 1975

Solar availability for space heating on coldest-weather days has been determined from an analysis of SOLMET data tapes. The tapes contain hourly readings of insolation and ambient temperature over the period from 1953 through 1975. Scatter diagrams of insolation versus heating degree-days, compiled on a daily basis, indicate a wide variation in the insolation level, even during coldest-weather periods. For all but one of the eight sites studied, the peak-day backup energy requirement of the solar system was in excess of 85 percent of the peak-day energy requirement of the conventional (nonsolar) heating system.