蔬菜差压预冷失水控制方法研究

预冷是对刚采收的果蔬迅速除去田间热，冷却到预定温度的过程，是果蔬流通、贮藏、加工重要的前处理技术。预冷与流通冷链的有机结合成为果蔬保持采后品质、扩大流通范围的重要技术保证。差压预冷是在冷库预冷的基础上弥补了其预冷时间长、不均匀等不足而研究发展起来的预冷技术，差压预冷是通过加大冷空气流经蔬菜表面的速度，提高蔬菜与冷空气之间的热交换来实现快速降低蔬菜温度的。

热水采暖管网失水控制

热水采暖管网失水的问题既威胁锅炉的安全运行，又造成能源的极大浪费，为此，有必要从根本加以杜绝。

热水管网失水的原因及控制方法

水在热网运行当中,是主要的介质,大量失水会使热网出现水力失调、用户室温低等危害。要保证系统平稳运行,就必须大量补水,其结果是锅炉、管网、用户系统内腐蚀加剧,堵塞增多,锅炉补水量加大,热效率低,由此给企业带来的损失也是很大的。

抑制‘甜春橘柚’贮藏中失水的研究

【目的】控制‘甜春橘柚’采后失水现象,探究一种能有效减少‘甜春橘柚’枯水粒化的综合型保鲜方法。【方法】对采后‘甜春橘柚’果实用不同冷激时间、不同浓度的保鲜剂涂膜、不同厚度的保鲜袋包装和不同贮藏温度多种措施进行处理,定期测定各处理的失重率,并以外观性状、汁胞粒化指数和失重率等为‘甜春橘柚’果实失水控制效果的综合评价指标。【结果】‘甜春橘柚’果实经冷激、涂膜、包装、冷藏处理后,果实的失重率显著低于对照,能有效控制采后‘甜春橘柚’果实在贮藏期间失水现象的发生。冷激10 min以上的果实失重率能维持在10%以内。浓度越高的甲壳素涂膜‘甜春橘柚’,控制果实的失水效果越好。用厚度为0.01、0.02和0.04 mm薄膜袋包装‘甜春橘柚’,形成的自发气调环境能有效抑制水分蒸腾。适当的低温贮藏也能较好地控制‘甜春橘柚’失水失鲜现象。【结论】在单因素试验基础上,通过L18(35)正交试验选出的能控制‘甜春橘柚’果实枯水现象的发生、降低汁胞粒化程度的最佳方案为:冷激处理15 min后再用0.4%(w)甲壳素溶液浸果(10 min)涂膜处理,而后用厚度为0.04 mm薄膜袋包装‘甜春橘柚’果实并置于10℃下冷藏。

盐227区块非常规井钻井液技术措施

一、钻井液技术施工难点1.平原组、明化镇组地层松软,防坍塌卡钻。2.二开以后采用清水钻进,将上部井眼打成开放式井眼,为后期施工的防糊工作打好基础,本井段缺失沙一段,进入沙河街组前,把失水控制在设计范围内。3.沙三段、沙四上部为砂泥互层,易垮塌,大位移水平井,钻进周期较长,这就要求钻井液有足够的润滑性,和较强的抑制性,来保证井壁稳定,防止发生井下复杂与事故。

Soil Erosion Changes over the Past Five Decades in the Red Soil Region of Southern China

This paper reports the dynamic changes of soil and water loss in the red soil region of Southern China since the 1950s. The red soil region covers eight provinces: Jiangxi, Zhejiang, Fujian, Anhui, Hubei, Hunan, Guangdong and Hainan. From the 1950s to 1986, the annual rate of soil erosion increased by 3.4%. From 1986 to 1996 and from 1996 to 2000, the annual rates of soil erosion decreased by 2.0% and 0.32%, respectively. Field surveys showed that from 2000 to 2005, the area of soil and water loss decreased annually by 1.2%. This decrease was a result of large-scale erosion control activities across China. Although the eroded soil has been restored, the restoration process is very slow and full restoration will take a long time. Our report suggests that controlling soil and water loss is a challenging task, and additional measures must be taken to effectively control the soil erosion in the red soil region.

Ammonia Volatilization from Urea Applied to Acid Paddy Soil in Southern China and Its Control

Results showed that ammonia loss from urea broadcast into floodwater and incorporated into soil at transplanting was as high as 40% of applied N,and the corresponding total nitrogen (N) loss was 56%.Ammonia loss was measured with simplified micrometeorological method (ammonia sampler),and total N loss was concurrently measured using ^15N balance technique.The experiment was conducted under strong sunshine conditions on acid paddy soil derived from Quaternary red clay.The ammonia loss in this particular condition was much greater than those obtained from previous studies when urea was also applied to acid paddy soil but under cloudy conditions.It is concluded that the strong sunshine conditions with high temperature and shallow floodwater during the period of present experiment favoured ammonia volatilization.Application of stearyl alcohol on the surface of the floodwater reduced ammonia loss to 23% of applied N.However,the effect of stearyl alcohol was short-lived,probably due to the microbiological decomposition.

Instability mechanism and control technology of soft rock roadway affected by mining and high confined water

Based on deformation and failure characteristics of the second belt conveyor roadway at level II of Zhuxianzhuang coal mine, laboratory experiments, numerical calculation and field test were adopted to analyze the composition and microstructure of mudstone, the law of mudstone hydration and its strength weakening induced by water, the characteristics of surrounding rock deformation and failure under the action of confined water. Results showed that montmorillonite clay minerals accounted for as much as 76% of mudstone, with a large number of pores existing in the microstructure. Besides, as the molecular structure of montmorillonite changed, mudstone microstructure damage occurred with the macroscopic manifestation of its theological instability. Weakening degree of confined water on residual strength of mudstone was almost 50%. The instability mechanism of soft rock roadway caused by high confined water is that surrounding rock circulates the process of ＂fracture-seepage-mud ding-closed＂ twice, which weakens its strength and leads to roadway instability. A combined support technology, namely the, ＂high-toughness sealing layer ＋ hollow grouting cables ＋ full-length anchoring bolts with deep borehole＂ was proposed. Based on field observation, the soft rock roadway was controlled effectively, which also verified the effectiveness of new control technology for surrounding rock.

Field experiments on greenhouse gas emissions and nitrogen and phosphorus losses from rice paddy with efficient irrigation and drainage management

Greenhouse gas emissions,nitrogen and phosphorous losses through ammonia volatilization,leaching and surface drainage from rice paddy under efficient irrigation and drainage were analyzed based on field experimental data in order to reveal the eco-environmental impacts of efficient irrigation and drainage on rice paddy.The results showed that total methane emission from rice paddy under the controlled irrigation was reduced by more than 80% and total nitrous oxide emission increased by 15.9% compared with flooding irrigation.Seasonal comprehensive global warming potentials(GWP) of methane and nitrous oxide were 62.23 gCO2 m-2 for rice paddy under the controlled irrigation,reduced by 68.0% compared with flooding irrigation.Due to large reduction in seepage and surface drainages,nitrogen and phosphorous losses through leaching were reduced by 40.1% and 54.8%,nitrogen and phosphorous losses through surface drainage were reduced by 53.9% and 51.6% from rice paddy under efficient irrigation and drainage compared with traditional irrigation and drainage.Nitrogen loss through ammonia volatilization was reduced by 14.0%.Efficient irrigation and drainage management is helpful to mitigate greenhouse gases emission,nitrogen and phosphorus losses and their pollution on groundwater and surface water.

Capacity of soil loss control in the Loess Plateau based on soil erosion control degree

The capacity of soil and water conservation measures, defined as the maximum quantity of suitable soil and water conservation measures contained in a region, were determined for the Loess Plateau based on zones suitable for establishing terraced fields, forestland and grassland with the support of geographic information system(GIS) software. The minimum possible soil erosion modulus and actual soil erosion modulus in 2010 were calculated using the revised universal soil loss equation(RUSLE), and the ratio of the minimum possible soil erosion modulus under the capacity of soil and water conservation measures to the actual soil erosion modulus was defined as the soil erosion control degree. The control potential of soil erosion and water loss in the Loess Plateau was studied using this concept. Results showed that the actual soil erosion modulus was 3355 t·km^(–2)·a^(–1), the minimum possible soil erosion modulus was 1921 t·km^(–2)·a^(–1), and the soil erosion control degree was 0.57(medium level) in the Loess Plateau in 2010. In terms of zoning, the control degree was relatively high in the river valley-plain area, soil-rocky mountainous area, and windy-sandy area, but relatively low in the soil-rocky hilly-forested area, hilly-gully area and plateau-gully area. The rate of erosion areas with a soil erosion modulus of less than 1000 t·km^(–2)·a^(–1) increased from 50.48% to 57.71%, forest and grass coverage rose from 56.74% to 69.15%, rate of terraced fields increased from 4.36% to 19.03%, and per capita grain available rose from 418 kg·a^(–1) to 459 kg·a^(–1) under the capacity of soil and water conservation measures compared with actual conditions. These research results are of some guiding significance for soil and water loss control in the Loess Plateau.