Spray Effect on the Thermal Performances of a Dry Cooling Tower

Pre-cooling the inlet air of a dry cooling tower by means of a spray can improve the tower performance during periods of high temperature.To study the spray effect on the thermal performance of natural draft dry cooling towers(NDDCTs),in this study 3-D numerical simulations of such a process have been conducted using Fluent 16.2(a two-way coupled Eulerian-Lagrangian approach).The considered NDDCT is 120 m high and only half system is simulated due to its structural symmetry.Three different spray strategies have been investigated at a typical crosswind speed of 4 m/s,which is the most frequent wind speed.The results have shown that:(1)The three implemented spray strategies can improve the thermal performance of the studied NDDCT with a vary-ing degree of success.In one case,the heat rejection rate can be increased by 35.2%,and the tower outlet water temperature can be decreased by 2.1℃ when compared with the no spray case;(2)To improve the thermal per-formance of the NDDCT using a small amount of water,the design of the spray pre-cooling system must include more nozzles on the windward and fewer or even no nozzles on the leeward sides of the NDDCT.

Experimental Study on Hydrothermal Drying for Sewage Sludge in Large-Scale Commercial Plant

The study was conducted to demonstrate the performance of the large-scale commercial plant of the hydrothermal drying of sewage sludge. Its performance was compared with that of the small-scale pilot facility to confirm the scaling effect of the facility. It has been shown that the optimum reaction temperature was 190℃ and reaction time was 30 minutes for both facilities. The dehydration performance of the products of the hydrothermal treatment and the natural drying performance of the dehydrated residue were almost the same for both facilities, which demonstrated that the small-scale pilot facility could simulate the commercial-scale plant well. With these optimum hydrothermal reaction conditions, the moisture content of the dehydrated product was less than 40% by the use of the frame filter, which had better dehydration performance than the centrifuge dehydrator. The moisture content of the dehydrated solid residue could be reduced less than 20% and 10% after 24 hours and 48 hours natural drying, respectively. The solubilization rate of sludge into the dehydrated liquid was 10% and 90% of the solid content in the raw sludge could be recovered as a dry solid fuel by this process with reduced energy requirement compared with conventional thermal drying processes. Too high reaction temperature or too long reaction time increased the content of solid material in the dehydrated liquid （solubilization rate of sludge） and reduced the yield of the dry solid fuel.

Changing the Moisture Content of the Spartina and Miscanthus and Willow Shoots during Storage in Natural Conditions

The aim of this study was to determine the characteristics of the distribution of energy plant moisture content along the height of their shoots and the dynamics of moisture during storage in natural conditions. The shoots of Spartina, Miscanthus and willow were used in the study. Entire shoots were cut into sections of 10 cm and for each set in monthly cycles for six months moisture content was evaluated. After a month＇s storage of freshly cut shoots the biggest decrease of content moisture in the shoots of Spartina and Miscanthus was recorded, by 31% and 22%, respectively, and the lowest in willow shoots （12%）. After sixth months of shoots storage the lowest moisture content （10%-12%） was reached in miscanthus. The most uneven moisture content along the height of shoots Spartina was characterized because on one third of the height from the bottom, the moisture content of shoots was 20%, and the top had moisture content in the range 5%-10%. Willow shoots were characterized by the smallest drop in moisture, and the final moisture content was about 23%, with the top part of moisture content of 10%-20%. The dynamics of moisture change during the six months of storage of grass shoots （Miscanthus and Spartina） in natural conditions under roofing was described by one power function regression, and willow by another one. Empirical models can be used to predict changes in moisture content of these plants in experiment conditions, since the coefficients of determination were 94.66% and 89.18%, respectively.

Analysis of the Influence of Different Drying Methods on the Active Ingredients of Fresh Medicine

The heating area of the material is large and the thermal efficiency is high,but it is n ecessary to control the suitable drying temperature ofdiffere nt medici nal materials to preserve the effective in gredients.D iff ere nt kinds of Chinese medicine need different drying conditions to fulfill good drying requirements.Natural drying in the shade is one of the traditional drying methods,which takes a long time and is easily affected by the weather.The water volatilizes slowly.It is prone to mildew and discoloration during the drying process.However,it can better preserve the volatile oil components of Chinese medicine.The hot-air drying machine has lower requirements.The medicinal materials have a large heating area and high thermal efficiency,but it is necessary to control the appropriate drying temperature of different medicinal materials in order to preserve the active ingredients of the medicinal materials;it is not suitable for medicinal materials that stick and bind easily.The microwave drying method possesses superiority in drying some valuable medicinal materials such as Ren she n(Radix et Rhizoma Ginseng)and Lurong(Co「nu Cervi Pantotrichum),and the effective ingredients are preserved at a high degree;it can also achieve the purpose of killing enzymes and protecting glycosides and have a good bactericidal effect,but it is not suitable for Chinese medicines containing heat-sensitive ingredients,because it will destroy most of the proteins,amino acids,and peptides of Chinese medicine and result in the loss of efficacy.The far-infrared drying method is suitable for drying thin-layer medicinal materials and is friendly to the environment.Freeze-drying can preserve the active ingredients very well and greatly retain the efficacy,but it has obvious limitations in preserving some Chinese medicinal materials that need to kill enzymes and protect glycosides;besides,the cost is relatively high and the drying time is long.

Impacts of reforestation on woody species composition,species diversity and community structure in dry-hot valley of the Jinsha River,southwestern China

To understand the impacts of reforestation on woody species composition,species diversity and community structure,seven plantation forests in dryhot valley of the Jinsha River in Southwest China were investigated,with adjacent wastelands,natural shrub grassland and a natural forest as references.Species importance value,species richness,species heterogeneity and Sorenson similarity index between plantations and the natural forest were analyzed.Results indicated that compared to wastelands and natural shrub grassland,reforestation improved species diversity and community structure,and more forest woody species found suitable habitats in plantations.Species diversity in understory of plantations and Sorenson similarity index were significantly negatively correlated with stem density in mature plantations(26-31 years old).Higher species diversity and Sorenson similarity index existed in mature sparse plantations due to lower stem density and more tree species planted initially.In contrast,reference natural forest,with species heterogeneity of 2.28 for shrub layer,showed the highest species diversity.It would take a long time for species composition and diversity to recover through reforestation in a dry-hot valley.Therefore,it was essential to protect remnant natural forests strictly and reforest with suitable management such as lower stem density and increasing genetic diversity of trees planted.

石斛夜光丸联合羟糖甘眼液治疗干眼临床研究

目的:观察石斛夜光丸联合羟糖甘眼液治疗干眼的临床疗效,并探索其作用机理。方法:干眼患者90例,按就诊先后顺序随机分为观察组、对照组,观察组口服石斛夜光丸联合局部滴用羟糖甘眼液;对照组局部滴用羟糖甘眼液。疗程2个月。观察治疗前后眼部及全身症状、泪膜破裂时间、泪液分泌量、角膜荧光素染色等疗效指标。结果:观察组总有效率为80%,对照组总有效率为65%,显效率及有效率与对照组比较具有统计学意义,观察组优于对照组。结论:口服石斛夜光丸联合局部点滴羟糖甘眼液可明显改善干眼症状,延长泪膜破裂时间,增加泪液分泌量,促进角膜上皮修复,疗效优于局部点滴羟糖甘眼液。

A decoupled method to identify affecting mechanism of crosswind on performance of a natural draft dry cooling tower

The natural draft dry cooling tower(NDDCT)has been increasingly used for cooling in power generation in arid area.As crosswind affects the performance of a NDDCT in a complicated way,and the basic affecting mechanism is unclear,attempts have been made to improve the performance of a NDDCT based on limited experiences.This paper introduces a decoupled method to study the complicated crosswind effects on the inlet and outlet of a NDDCT separately by computational fluid dynamics(CFD)modeling and hot state experiments.Accordingly,the basic affecting mechanism of crosswind on the NDDCT performance is identified.Crosswind changes the inlet flow field of a NDDCT and induces mainstream vortices inside the tower,so as to degrade the ventilation.Besides,low crosswind deflects the upward plume at the outlet to further degrade the ventilation,while high crosswind induces the low pressure area at the outlet to reduce the ventilation degradation.

泪然用于白内障术后干眼治疗的临床观察

目的了解泪然对于白内障患者超声乳化术后干眼的治疗是否有效及安全。方法选择白内障超声乳化术后有干眼的137例,随机分为两组,A组超声乳化术后单用典必殊眼液,B组联合应用典必殊眼液和泪然眼液滴眼。分别对137例患者术前、术后1 d、1周及1、2、3个月行角膜荧光素染色(FL),泪膜破裂时间(BUT)和SchirmerⅠ检查及干眼症状的调查结果做统计学分析。结果手术前及手术后1 d,A组和B组在FL、BUT、SchirmerⅠ及干眼症状四个检查值经统计学分析无明显差异;手术后1周、1个月,B组BUT较A组更长,FL值小于A组,干眼症状少于A组,统计学上有显著差异,SchirmerⅠ两组在统计学上无明显差异;手术后2、3个月,B组BUT较A组长,FL值小于A组,统计学上有显著差异;SchirmerⅠ及干眼症状,两组在统计学上无明显差异。结论白内障超声乳化术后早期,泪膜稳定性明显下降,出现干眼症状,加用泪然眼液滴眼后,泪膜稳定性提高,干眼症状好转,提示白内障超声乳化术后早期使用泪然对干眼治疗有效、安全。

Experimental Study of Effects of Cross Wind on Flow in Natural-draft Dry-cooling Towers

The effects of cross wind on the flow field in natural draft dry cooling towers are studied experimentally in a wind tunnel using similarity principles. Particular attention is focused on the flow fields inside the tower. The study illustrates the influence of wind on the cooling tower performance and proposes a number of techniques for improving tower performance with a cross wind

泪然联合重组牛碱性成纤维细胞生长因子对青光眼滤过术后干眼症的疗效分析

目的：分析泪然联合重组牛碱性成纤维细胞生长因子对青光眼滤过术后干眼症的疗效。方法：将我院2014年4月至2015年8月收治的64例青光眼滤过术后干眼症患者作为研究对象，随机（随机数字表法）分为治疗组（n=32）与对照组（n=32）。给予对照组患者双眼滴注重组牛碱性成纤维细胞生长因子滴眼液，每次1~2滴，每日4次；治疗组在此基础上加滴泪然滴眼液，每次1~2滴，每日4次。比较两组患者治疗前后临床疗效、症状及体征评分情况，干眼相关辅助检查结果、治疗前后各时间点角膜中央知觉情况以及用药安全性。结果：治疗后，观察组患者的总有效率（96.88%）明显高于对照组患者（71.88%），数据差异有统计学意义（P〈0.05）。两组患者的感觉性症状和眼表体征评分均有所改善，且观察组患者治疗后的感觉性症状评分（1.08±0.97）和眼表体征评分（0.96±0.35）均明显低于对照组患者（2.77±1.08）、（2.15±0.66），差异有统计学意义（P〈0.05）。两组患者的泪膜破裂时间、泪液分泌时间和角膜荧光染色评分均有明显改善，且观察组患者的相关评分（8.21±1.56）、（6.77±2.79）、（0.45±0.74）分均明显优于对照组患者（7.85±1.65）、（6.36±2.76）、（0.99±0.88），其差异具有统计学意义（P〈0.05）。治疗后3个月和6个月后，患者角膜知觉逐渐恢复，且治疗组患者恢复情况显著优于对照组，数据差异有显著统计学意义（P〈0.05）。结论：泪然联合重组牛碱性成纤维细胞生长因子治疗青光眼过滤术后干眼症的效果显著，不仅可以有效改善患者临床症状，也能改善患者的泪液分泌功能，还能有效改善患者角膜知觉，无不良反应，安全性较高。

中药熏蒸联合新泪然滴眼液治疗白内障术后干眼症的临床研究

目的探讨中药熏蒸联合新泪然滴眼液治疗白内障术后干眼症的临床效果。方法筛选我院患有白内障术后干眼症患者90例,经随机数字表法分为对照组与观察组,各45例。对照组给予新泪然滴眼液疗法,观察组在此基础上联合应用中药熏蒸,对比2组泪膜破裂时间(BUT)、泪液分泌试验(ST)及临床疗效。结果观察组有效率高于对照组(P<0.05);与对照组比,治疗后观察组ST及BUT指标值均大幅升高,具有显著性差异(P<0.05)。结论中药熏蒸及新泪然滴眼液联合疗法对改善白内障术后干眼症效果较为明显,可有效缓解症状,具有推广价值。