水厂过滤工艺水头损失计算与试验

基于水厂实际生产过程,利用堵塞计测定滤层中的压力值的方法进行了水头损失的计算,建立了水厂实际生产中水头损失的模型,并利用差分进化算法对模型进行了参数辨识,从而确定了滤池总水头损失的数学模型.结果表明:模型较为准确可靠.生产过程中可根据该模型实时计算出滤池总水头损失,为水厂过滤过程的优化运行打下了良好的基础.     

羧甲基纤维素凝胶小球的制备及其对肥料的缓释作用研究

制备一种羧甲基纤维素(CMC)凝胶,以凝胶小球失水率变化反映交联过程。结果表明,交联剂 Fe³⁺ 浓度越高,失水越快且失水率越大。制备凝胶小球时所用 CMC 溶液质量分数越高,失水率越低。DSC 分析凝胶的降温凝固过程表明,CMC 小球中的水以结合状态为主,且制备小球时所用的交联时间越长,凝胶含水率越低。采用硝酸钾作为化肥的模型化合物,释放实验表明,当硝酸钾在 CMC 凝胶中的载量为 5.0% 时,缓释效果明显。     

Effect of Immersion Time in Osmosis and Ultrasound on Papaya Cell Structure during Dehydration

The effect of ultrasound-assisted osmotic dehydration applied at atmospheric pressure for different lengths of time on papaya tissue structure was evaluated. Ultrasound induced the loss of cellular adhesion, formation of large cell interspaces, and light rupture of the cell walls. The changes in the tissue structure caused by ultrasound application increased sugar loss, water loss, and effective water diffusivity. Ultrasound-assisted osmotic dehydration induced a gradual distortion in the shape of the cells, loss of cellular adhesion, and the formation of large channels caused by rupture of the cell walls. The changes caused by the application of osmotic dehydration resulted in high water loss and sugar gain.     

富液式铅酸蓄电池失水率预测公式的研究

在法拉第电解定律的基础上,推导了在充电试验的基础上计算富液式铅酸电池在试验条件下的失水率预测公式,并在此基础上推导了在国标失水率试验条件下的失水率预测公式。通过失水率的失重法进行验证,预测公式有很大程度的准确性,计算方法是可行的。     

Relationship Between Interfacial Water Layer Adhesion Loss of Silicon/Glass Fiber-Epoxy Systems: A Quantitative Study

Water at the polymer/substrate interface is often the major cause of adhesion loss in coatings, adhesives, and fiber-reinforced polymer composites. This study critically assesses the relationship between the interfacial water layer and the adhesion loss in epoxy/siliceous substrate systems. Both untreated and silane-treated Si substrates and untreated and silane-treated E-glass fibers were used. Thickness of the interfacial water layer was measured on epoxy/Si systems by Fourier transform infrared-multiple total internal reflection (FTIR-MTIR) spectroscopy. Adhesion loss of epoxy/Si systems and epoxy/E-glass fiber composites was measured by peel adhesion and short-beam shear tests, respectively. Little water accumulation at the epoxy/Si substrate interface was observed for silane-treated Si substrates, but about 10 monolayers of water accumulated at the interface between the epoxy and the untreated Si substrate following 100 h of exposure at 24 °C. More than 70% of the initial epoxy/untreated Si system peel strength was lost within 75 h of exposure, compared with 20% loss after 600 h for the silane-treated Si samples. Shear strength loss in composites made with untreated E-glass fiber was nearly twice that of composites fabricated with silane-treated fiber after 6 months of immersion in 60 °C water. Further, the silane-treated composites remained transparent, but the untreated fiber composites became opaque after water exposure. Evidence from FTIR-MTIR spectroscopy, adhesion loss, and visual observation strongly indicated that a water layer at the polymer/substrate interface is mostly responsible for the adhesion loss of epoxy/untreated siliceous substrate systems and epoxy/untreated glass fiber composites and that FTIR-MTIR is a viable technique to reliably and conveniently assess the adhesion loss attributable to water sorption at the interface.     

萘磺酸系减水剂的改性研究

对萘系高效减水剂进行了改性研究。采用溶液聚合,合成了一种低坍损、高性能减水剂;讨论了合成机理,测试了样品使用性能;结果表明:该产品具有高减水性、优良的工作性能、混凝土性能等特性。     

一种改性淀粉钻井液降滤失剂的合成与性能评价

以可溶性玉米淀粉、AMPS、DMDAAC、AM四元共聚,制得一种两性离子改性淀粉钻井液降滤失剂。结果表明,该聚合物降滤失剂在淡水基浆、盐水基浆、人工海水基浆中均具有较好的降失水性能,1.0%的产品加量,淡水基浆中API失水为6 mL,饱和盐水基浆中API失水为8 mL,人工海水基浆中API失水为8.4 mL;0.6%的产品加量的淡水基浆在150℃、3.5 MPa下的失水量为24.2 mL,基浆在180℃下热滚16 h后性能无明显变化,页岩滚动回收1次、2次,回收率均在90%以上。     

钢毛过滤用于水质保障的试验研究

为了提高水质保障的效率,设计出以钢毛为滤料的过滤装置,并对原水进行了直接过滤的试验研究。钢毛过滤具有成熟期短、悬浮物去除能力强、过滤周期内水头损失较小、水头损失分布均匀的优点。在实验室研究的基础上,现场对钢毛过滤处理水库原水进行了研究。钢毛过滤在高速连续运行的条件下,具有较好的处理能力。同时,钢毛过滤结合紫外线消毒工艺,处理水质较好,能够满足水质保障的要求。     

降低低温甲醇洗装置甲醇损耗的对策

为了降低合成氨生产过程中甲醇损耗量,减少环境排放,节约成本,调查分析确定造成甲醇损耗的九个因素。通过合理措施的实施．优化硫化氢浓缩塔尾气放空洗涤系统操作,降低甲醇脱水塔排放废水的甲醇含量在0．2％1-2内,减少甲醇开车损耗,2011年甲醇损耗同比降低了36％。     

Determination of water content of granulated detergents

A quick analytical procedure was described for the determination of water content of granulated detergents. A constant weight loss of sample was obtained within 5 min by microwave drying. The weight loss agrees with the water content by the modified distillation method. The coefficient of variation was 0.7%.     

Synthesis and working mechanism of fluid loss additive by freeze-drying method

ABSTRACT

A liquid fluid loss additive was synthesized by 2-acrylamide-2-methyl propane sulfonic acid (AMPS), N, N-dimethyl acrylamide (DMAM), maleic anhydride (MA), and allyl alcohol polyoxyethylene ether (APEG), which named ADMA (AMPS/DMAM/MA/APEG). The liquid ADMA was freeze-dried and grinded to a white powdery polymer (FDADMA). The FDADMA had less fluid loss volume and superior rheological properties both in fresh water and sea water, while ADMA merely exhibited good filtrate loss control and rheology in fresh water. Besides, the surface morphology of FDADMA was dendritic in sea water after freeze drying, while the ADMA was severely aggregated in sea water.     

De-painting with high-speed water jets: Paint removal process and substrate surface roughness

Although the use of water jets for paint removal processes is an accepted procedure, there are just a few studies known which discuss parameter optimization and surface topography in some detail. The paper investigates the effects of water jet kinetic energy and stand-off distance on the mass loss of an organic paint system applied to a steel substrate. It was shown that the material removal process was characterized by a combination of loading intensity and loading frequency. Water drops, formed in the water jet at long stand-off distances, played a notable role. For rather high water jet energies, mass loss exhibited high values at high stand-off distances. For lower water jet energies, however, maximum material loss values appeared at a critical stand-off distance. The transition water jet energy was 600 kJ. It could be shown that the steel substrate topography was not compromised due to secondary surface preparation by water jets. Secondary blast cleaning, however, reduced the profile of the substrate.     

De-painting with high-speed water jets: Paint removal process and substrate surface roughness

Although the use of water jets for paint removal processes is an accepted procedure, there are just a few studies known which discuss parameter optimization and surface topography in some detail. The paper investigates the effects of water jet kinetic energy and stand-off distance on the mass loss of an organic paint system applied to a steel substrate. It was shown that the material removal process was characterized by a combination of loading intensity and loading frequency. Water drops, formed in the water jet at long stand-off distances, played a notable role. For rather high water jet energies, mass loss exhibited high values at high stand-off distances. For lower water jet energies, however, maximum material loss values appeared at a critical stand-off distance. The transition water jet energy was 600 kJ. It could be shown that the steel substrate topography was not compromised due to secondary surface preparation by water jets. Secondary blast cleaning, however, reduced the profile of the substrate.     

Effect of water depth on ammonia loss from lowland rice

This paper reports a study on the effects of water depth in modifying rates of ammonia emission and total nitrogen loss from flooded rice fields after fertilization with urea. Ammonia loss was determined by the mass balance micrometeorological method and total nitrogen loss by¹⁵N balance.Initially ammonia was lost at a faster rate from the shallow (0.05 m) than from the deep (0.14 m) floodwater; this was due to higher ammoniacal nitrogen concentrations and higher temperatures in the shallow water. Emission rates were more nearly comparable later in the experiment, but overall, 26% of the applied nitrogen was lost as ammonia from the shallow pond and only 18% from the deep pond.Even though changes in water depth markedly affected ammonia emission rates and the amounts of ammonia lost, they did not significantly affect total nitrogen loss. The results suggest that management practices based only on changes in water depth may not result in increased efficiency of fertilizer nitrogen for flooded rice.     

Factors controlling ammonia loss from trash covered sugarcane fields fertilized with urea

Ammonia losses following surface applications of urea to trash covered sugar cane fields were investigated in four climatic zones of tropical Queensland. Volatilization of ammonia and evaporation of water were determined by micrometeorological techniques. The results showed that the pattern, rate and extent of ammonia loss were controlled by the availability of water in the trash and its evaporation. Water added by dewfall, rainfall or condensation of evaporated soil moisture dissolved some of the urea and allowed it to be hydrolyzed to ammonia by the urease enzyme in the sugarcane residues; when the water evaporated, ammonia was lost to the atmosphere.In the dry climatic zone, where no rain or dew fell, water addition to the trash by condensation of evaporated soil moisture was not sufficient to dissolve much urea so very little ammonia was lost. In the cool and warm moist zones, small additions of water to the trash from dew, light rain and condensation maintained a slow but steady pattern of ammonia loss over a period of six weeks and resulted in losses of 32% and 39% of the applied nitrogen. At the site in the wet zone, heavy rainfall apparently washed the urea from the trash layer into the soil and limited ammonia loss to 17% of the applied nitrogen.Substitution of ammonium sulfate for urea reduced ammonia loss to less than 1.8% of the applied nitrogen.     

TESTS FOR HOT-WATER RESISTANCE OF TANK ENAMELS*

The resistance to attack by hot water of a representative group of commercial enamels, designed especially for use on hot-water tanks, and of several nontank enamels was measured by the following three types of test: (A) loss of gloss after periods up to several hours in a conventional autoclave with distilled water, (B) loss of gloss after one day to two weeks in apparatus which kept the specimens in contact with constantly changing, boiling distilled water, and (C) loss in thickness after periods up to 5000 hours (208 days) in a modified autoclave with circulating aerated tap water under pressure. The tests are described in detail, comparisons are made, and the loss-of-gloss test with boiling distilled water as used in Commercial Standard CS115–44 is discussed.     

MoO3／Al2O3催化剂上MoO3的脱附平衡和流失速度

分别测定了在氮，水气氛下ＭｏＯ３自ＭｏＯ３／Ａｌ２Ｏ３催化剂上脱附的平衡数据。发现尽管ＭｏＯ３和Ａｌ２Ｏ３存在着强的化学作用，但气固平衡关系仍然可用Ｆｒｅｕｎｄｌｉｃｈ方程式描述。讨论了钼升华流失速度方程式与Ｆｒｅｕｎｄｌｉｃｈ式的关系。发现在氮水混合气流中，钼的流失总速度可以用它们单独存在时流失速度线性加和来表示。给出了水分压对流失速度影响的级数值。这一综合速度方程式经简化后，可以用于工业过程中钼流失数据的估算。     

Creosote Bush (Larrea tridentata) Resin Increases Water Demands and Reduces Energy Availability in Desert Woodrats (Neotoma lepida)

Although many plant secondary compounds are known to have serious consequences for herbivores, the costs of processing them are generally unknown. Two potential costs of ingestion and detoxification of secondary compounds are elevation of the minimum drinking water requirement and excretion of energetically expensive metabolites (i.e., glucuronides) in the urine. To address these impacts, we studied the costs of ingestion of resin from creosote bush (Larrea tridentata) on desert woodrats (Neotoma lepida). The following hypotheses were tested: ingestion of creosote resin by woodrats (1) increases minimum water requirement and (2) reduces energy available by increasing fecal and urinary energy losses. We tested the first hypothesis, by measuring the minimum water requirement of woodrats fed a control diet with and without creosote resin. Drinking water was given in decreasing amounts until woodrats could no longer maintain constant body mass. In two separate experiments, the minimum drinking water requirement of woodrats fed resin was higher than that of controls by 18-30% (about 1-1.7 ml/d). We tested several potential mechanisms of increased water loss associated with the increase in water requirement. The rate of fecal water loss was higher in woodrats consuming resin. Neither urinary water nor evaporative water loss was affected by ingestion of resin. Hypothesis 2 was tested by measuring energy fluxes of woodrats consuming control vs. resin-treated diets. Woodrats on a resin diet had higher urinary energy losses and, thus, metabolized a lower proportion of the dietary energy than did woodrats on control diet. Fecal energy excretion was not affected by resin. The excretion of glucuronic acid represented almost half of the energy lost as a consequence of resin ingestion. The increased water requirement and energy losses of woodrats consuming a diet with resin could have notable ecological consequences.     

Embedded NMR sensors to monitor evaporable water loss caused by hydration and drying in Portland cement mortar

Providing adequate moisture content in cement-based materials is important during hydration of the cement paste to ensure proper development of their mechanical and durability properties. Subsequently, water is involved in the deterioration of concrete either as a pure liquid or by carrying aggressive species. This paper explores the use of small embedded NMR sensors to monitor evaporable water loss in Portland cement mortars. Results indicate that these sensors are effective in detecting loss of evaporable water due to hydration and drying. During drying, the mass loss is linearly proportional to the NMR signal loss. In addition, the amount of evaporable water detected with the sensor has a good correlation with the amount of evaporable water in a companion specimen tested in a traditional low field magnet by NMR and by gravimetric measurements.     

Nitrogen balance for potato crops in the southeast pampas region, Argentina

The aim of this work was to build an N mass balance for the potato crop under irrigation conditions in the southeast pampas (Argentina) as a function of N rate and gravitational water. The experiment was developed in a Typic Argiudoll soils during five growing seasons using N treatments. Yield, N concentration, N accumulated and dry matter content in the tubers were different between years by effect of the N rates, the irrigation management and precipitations. Fertilizer N recovery in tubers decreased as the N rate and the volume of gravitational water increased. Soil residual N increased with the N rate and decreased with gravitational water. N loss increased with the N rate and the volume of gravitational water, so it is highly possible that nitrate leaching is the most important loss process. N loss means ranged from 12 to 57 % with the lowest and highest hydric excess (73 and 479 mm, respectively). N loss may become the largest N sink when there is excess of water. It is recommended to adapt N fertilization strategies with a proper irrigation management.