乌兰察布地区冷凉蔬菜紫甘蓝生长发育气象条件分析及气象灾害影响与防御

随着生活经济水平的提高,人们追求更健康且营养价值较高的冷凉蔬菜。紫甘蓝,又称红甘蓝、赤甘蓝,俗称紫包菜,较普通甘蓝所富含的营养元素多,是一种比较受欢迎的高档绿色蔬菜。近年来在不同冷凉地区种植,不仅丰富了蔬菜种类,可为消费者提供更多的多种选择,还为农民带来了较高的经济收益。乌兰察布地区气候适宜种植紫甘蓝,近几年,多地区有种植历史,且已经形成了较好的产业格局。紫甘蓝作物适应性强,是耐寒、抗热、喜阳光的一种蔬菜,生命力非常旺盛。为实现紫甘蓝产量和品质的提高,获得稳定高产,对紫甘蓝生长发育期全阶段气温、降水、土壤湿度等气象条件进行分析,找出适合本地区适应生长发育的气象条件指标。本文利用历年4—9月气温、降水、日照和地温等气象资料,采用对比分析方法,从热量和水分等对紫甘蓝生长发育期气象条件进行分析,并对其异常天气对紫甘蓝生长发育过程中产生的影响以及如何应对进行阐述,有效防御气象灾害带来的不利影响,合理利用气候资源,趋利避害,为紫甘蓝育苗、定植、田间管理以及防治病虫害等工作提供科学依据。

渭北高原沟壑区主要立地类型水热变化及对刺槐生长影响研究

渭北高原沟壑区主要立地类型水热变化及对刺槐生长影响分析结果表明:在局部范围内,热量因子与刺槐生长没有明显一致性,热量因子不是划分渭北高原沟壑区立地类型的主导因子;水分与刺槐生长之间关系密切(r=0.8965),说明水分是影响刺槐生长的主要因素,地形和土壤则是划分渭北旱原立地类型的主要因子。主要立地类型刺槐生长结果表明:刺槐适生的立地类型为:沟底、原面、沟坡阳向的上部和下部、宽梁顶等黄土型和沟底石砾土型,其它类型不适宜刺槐生长。

Measurement and engineering application of adsorbed water content in fine-grained soils

In this paper,the content and density of adsorbed water in fine-grained soil are determined.According to the test results,the calculation method of compaction degree of the solid-phase and void ration of soil is improved.Four kinds of fine-grained soils from different regions in China were selected,and the adsorbed water content and density of four kinds of fine-grained soils were determined by thermogravimetry and volumetric flask method.Furthermore,SEM and XRD experiments were used to analyze the differences in the ability of each soil sample to absorb water.In order to study the compression characteristics of adsorbed water,four saturated soil samples were tested by consolidation method.The results show that the desorption temperature range of the adsorbed water and its density were equal to 100−115℃and 1.30 g/cm^(3),respectively.Adsorbed water plays a positive role in keeping the compressibility of fine-grained soil at a low rate when it has high water content.Besides,adsorbed water can be a stable parameter and is difficult to discharge during the operation period of subgrade.The settlement of fine-grained soil embankment is predicted by engineering example,and compared with the result of conventional calculation method.The results show that it is more close to the field monitoring results by using the improved void ratio of soil as the parameter.

Thermal Dehydration Kinetics of Gypsum and Borogypsum under Non-isothermal Conditions

Thermal dehydration of gypsum and borogypsum was investigated under nonisothermal conditions in air by using simultaneous thermogravimetric-differential thermal analyzer. Nonisothermal experiments were carried out at various linear heating rates. Kinetics of dehydration in the temperature range of 373-503 K were evaluated from the DTA (differential thermal analysis)-TGA (thermogravimetric analysis) data by means of Coats-Redfern,Kissinger and Doyle Equations. Values of the activation energy and the pre-exponential factor of the dehydration were calculated. The results of thermal experiments and kinetic parameters indicated that borogypsum is similar to gypsum from dehydration mechanism point of view although it consists of boron and small amount of alkali metal oxides.

Double-diffusive Fluxes of Salt and Heat in the Upper Layer of North Pacific Intermediate Water

Almost half of the oceanic water columns exhibit double-diffusion. The importance of double-diffusion in global oceans’ salt and heat fluxes, water-mass formation and mixing, and circulation is increasingly recognized. However, such an important physical process in the ocean has not been well studied. One of the reasons is the difficulty of parameterizing and quantifying the processes. The paper presented here attempts to quantify the double-diffusive fluxes of salt and heat in the ocean. Previous qualitative analysis by applying the water-mass Turner angle, mTu, to the North Pacific Intermediate Water (NPIW) layer showed a favorable condition for salt-fingering in the upper NPIW due to the overlying warm/salty water above the cold/fresh NPIW core, and a doubly-stable condition in the lower NPIW where potential temperature decreases with depth while salinity increases, inducing double stratification with respect to both potential temperature and salinity. The present study gives a quantitative estimate of double-diffusive fluxes of salt and heat contributed by salt-fingering in the upper NPIW layer.

Drying of Fish Sardines in Oman Using Solar Tunnel Dryers

This paper deals with the design, construction and performance evaluation procedure of a solar tunnel dryer in drying fish. A 12 meter long and 2 meter width half-circled tunnel was designed and constructed to dry about 50-100 kg of freshly harvested fishes per batch. The half of the tunnel base was used as the flat plate air heating solar collector and the remaining half as a dryer. The drying air was forced from the collector region （north side） to the drying region （south side） of the half circled tunnel where the product is to be dried. The drying temperature could be easily raised by some 5-30 ℃ above the ambient temperature inside the tunnel at an air velocity of approximately 0.2 m/sec. The test was conducted with 51.5 kg freshly harvested sardines （hall-load） with initial moisture content of 66.5% （wet-basis） to analyze the performance of the dryer. The fishes were dried to a final average moisture content of 15.5% （wet-basis） within three days （30 hours）. It was possible to reach the moisture content level for safe storage within less than three days （30 hrs） with solar tunnel dryer and 7 days in open air natural sun drying. The improvement in the quality of fishes in terms of color, brightness, flavor, and taste and food value was distinctly recognized.

Effect Mechanism of Structure-Changed Water on Heat Stability of Lysozyme

Based on the mechanism of the effect of hydration on the heat stability of lysozyme and the theory of water molecule clusters, the effect of structure-changed water on heat stability of lysozyme has been studied. The results obtained by differential scanning calorimetry (DSC) showed that the thermal denaturation temperature of lysozyme had been elevated 8.47 K through hydration of lysozyme with processed water whose structure had been changed so it was called "structured water" compared to ordinary water. The reason is that structured water changed the dipole moment of water molecules and easily formed cyclic water hexamer or cage-like water hexamer, so that the interacting force of maintaining three-dimensional conformation of lysozyme could be reinforced.

Simulation Study on a Heat Pump System Using R744/R290 as Refrigerant

Based on the Chinese National Standards involving heat pump water heater and space heating system, performances of the R744/R290 subcritical heat pump system have been discussed and compared with those of the R22 system, which is widely used in heat pump systems in China nowadays. It can be indicated that R744/R290 mixture can work efficiently as a refrigerant for heat pumps with a large heat-sink temperature rise. When mass fraction of R290 is increased, discharge pressure is reduced. Under the nominal working condition, there is an optimum mixture mass fraction of 20/80 for R744/R290 under conventional condensation pressure. Both the heating COPhs （coefficient of performance） and volumetric heating capacity are increased by about 12.62% and 34.24% respectively compared with those of R22 based system. But for the heat sink with a small temperature rise, R744/R290 system has poorer performances than R22 system. When heat transfer pinch point in evaporator and condensation processes is considered, the degree of superheat has a negative influence upon system performances under the given conditions.

Thermal Analysis of Composite Cements

The hydration of cement compounds gives hydrated compounds, which allow linking together, the different particles and aggregate of cement, and gives the concrete the required qualities. The dynamics of hydration reactions will depend on many factors, such as the fineness of cement, the ratio w/c during hydration, temperature, mixing technique, and the presence of additives in blended cement, as pozzolan, tuff and slag from blast furnaces. We studied the thermal and kinetic reactions of Portland cement hydration, and its variants with different additions using a differential scanning calorimetric analysis. The parameters from these models of curves allow us to evaluate the enthalpies, and the degree of progression of this blended cement, and finally determine their activation energies. We can say that the hydration of Portland cement is due to a series of reactions as （ C3S,C2S,C3A and C4AF reactions with water） and each of them, has its own kinetic, the experimental measurement of the heat of hydration, allows us to represent the overall kinetics of these reactions values of activation energy, they are therefore apparent and global energy. In our experiments, significant differences in these physicochemical parameters were observed, depending on the additive used.

Sensitivity of Tropical Cyclone Precipitation to Atmospheric Moisture Content: Case Study of Bilis (2006)

In this article, the authors used the Weather Research and Forecast model to investigate the sensitivity of tropical cyclone Bilis' total precipitation to ambient water vapor content. The tropical cyclone precipitation decreased dramatically with the reduction of the ambient water vapor content in the atmosphere. The decrease of precipitation can be explained by two mechanisms. First, as the major source of precipitation, moisture conver-gence decreases accordingly with the moisture content. Second, the tropical cyclone (TC) size reduction due to the moisture decrease influences the precipitation area. Both mechanisms were observed in this study.

Experimental and theoretical study on thermal and moisture characteristics of new-type bamboo structure wall

Thermal and moisture characteristics of the bamboo structure wall were tested in natural climate and three representative variation processes of heat and moisture： heating from solar radiation in summer at normal temperature and humidity, heating from solar radiation in summer at normal temperature and high humidity after rain, humidifying from brash in summer at high temperature and normal humidity. The results show that, in summer, the largest temperature difference between external and internal surface of the 28 mm-thick bamboo plywood wall is 11.73℃ （at 15：40） and the largest strain difference is 136 μm/m （at 18：50）, both in ambient and indoor conditioned environment. In heating process, lengthways of the wall surface are in contracting strain while transverse ways are in expanding strain at initial stage and in contracting strain during later period. When the high temperature wall is humidified by rain, the surface temperature drops, moisture content increases and the expanding strain is presented on the surface during the whole process. Temperature and moisture content are two important factors which affect thermal and moisture stress （TMS） of the bamboo structure wall. The TMS is not only related to temperature and moisture content, but also greatly affected by temperature gradient, moisture content gradient and rates of changing.

The Effect of Micro Air Movement on the Heat and Moisture Characteristics of Building Constructions

The research focuses on the effect of air movement through building constructions. Although the typical air movement inside building constructions is quite small （velocity is of order -10-5 m/s）, this research shows the impact on the heat and moisture characteristics. The paper presents a case study on the modeling and simulation of 2D heat and moisture transport with and without air movement for a building construction using a state-of-art multiphysics FEM software tool. Most other heat and moisture related models don＇t include airflow or use a steady airflow through the construction during the simulation period. However, in this model, the wind induced pressure is dynamic and thus also the airflow through the construction is dynamic. For this particular case study, the results indicate that at the intemal surface, the vapor pressure is almost not influenced by both the 2D effect and the wind speed. The temperatures at the inner surface are mostly influenced by the 2D effect. Only at wind pressure differences above 30 Pa, the airflow has a significant effect. At the extemal surface, the temperatttres are not influenced by both the 2D effect and the wind speed. However, the vapor pressure seems to be quite dependent on the wind induced pressure. Overall it is concluded that air movement through building materials seems to have a significant impact on the heat and moisture characteristics. In order to verify this statement and validate the models, new in-depth experiments including air flow through materials are recommended.

河南省济源市农业气候资源的变化特征分析

对河南省济源市1971-2000年的气温、降水量、日照时间及几个重要的界限温度的活动积温、等作为主要研究对象进行统计分析,并简要分析其对农业的影响,结果表明:济源市气候趋向暖干化,特别是90年代升温最为明显;降水为减少趋势,从80年代开始就比较明显;日照时间从80年代开始迅速减少;各重要界限温度的活动积温随年代增加。此趋势对农业生产有利有弊,将会影响到农业生产的布局和结构。