Shape memory effect and properties memory effect of polyurethane

The relationship between shape and properties memory effect, especially viscoelastic properties of polyurethane under study is the main aim of this research work. Tensile tests have been performed in order to introduce 100% of deformation in the polyurethane samples. Under this deformation, stress–relaxation experiments have been performed in order to eliminate the residual stresses. This deformation of the samples has been fixed by cooling. Recovery tests, then, were carried out at different isothermal temperatures that varied from 30°C to 60°C. Viscoelastic behavior has been studied by a biparabolic model and by using the Cole–Cole method. It was shown that this model describes the behavior of the polymer at the different states of shape memory tests. The constants of this model then have been determined. This study leads to a better understanding of the mechanism of shape memory effect. The comparison between the virgin polymer and the polymer after a recovery test by DMTA (dynamic mechanical thermal analysis) and by Cole–Cole method has illustrated that the polymer does not obtain its initial properties even when it was totally regained its initial shape. These results have been confirmed by three successive shape memory tests on the same sample and by comparing the mechanical characteristics of different cycles because “shape memory effect” and “properties memory effect” do not follow the same mechanisms. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The effect of wall absorption on the Toms effect

The effect of the adsorption of Polymer Molecules to tube walls on the Toms effect has been investigated, whereby strong and weak adsorbing tube materials for like test distances were used.For Reynold's numbers between 70,000 and 100,000, at a pressure difference of approximately 1 atm, the reduction of pressure drop because of a better adsorption is influenced only insignificantly.Since there were reported much more positive results in a publication by Hand and Williams[1], we try to give an interpretation for this discrepancy.     

工业废水排放量变化的密度效应和增长效应

以可持续发展理论为基础,运用物质减量反弹效应的方法,给出了工业废水排放量变化的密度效应和增长效应计算公式,并根据1991～2004年<中国统计年鉴>中公布的数据,对全国工业废水排放量变化的密度效应和增长效应进行了计量分析.结果表明,1997年以前,密度效应比增长效应作用明显,全国工业废水排放量呈现下降趋势;1997年以后,增长效应比密度效应作用明显,全国工业废水排放量呈现上升趋势,特别是近3年增长显著.     

调节池预曝气对一体化AO装置运行效果的改善

针对河南永银化工实业有限公司生活污水处理系统一体化AO装置出水不能满足地方环保要求的问题,对其调节池进行了间歇预曝气技术改造。通过改造,改善了一体化AO装置的运行效果,提高了出水水质,使出水COD_(Cr)、NH_3-N能够达到排放指标的要求。     

有机膨润土对造纸黑水的处理效果

利用不同用量十六烷基三甲基溴化铵(CTMAB)对膨润土进行改性制备有机膨润土,并研究了有机膨润土的用量、介质pH值、作用时间等因素对有机膨润土去除造纸废水COD和色度的影响。试验结果表明:在同一影响因素条件下,有机膨润土对造纸废水COD和色度的去除率随着CTMAB用量的增加而增加。在废水COD的质量浓度为952.3mg/L、色度A500为1.015、pH值为2的情况下,有机膨润土用量为20g/L时对COD和色度的去除率分别达到84.7%和99.5%。     

Numerical study of instability of nanofluids: the coagulation effect and sedimentation effect

This study is a numerical study on the coagulation as well as the sedimentation effect of nanofluids using the Brownian dynamics method. Three cases are simulated, focusing on the effects of the sizes, volume fraction, and ζ potentials of nano-particles on the formation of coagulation and sedimentation of nanofluids. The rms fluctuation of the particle number concentration, as well as the flatness factor of it, is employed to study the formation and variation of the coagulation process. The results indicate a superposition of coagulation and sedimentation effect of small nano-particles. Moreover, it is stable of nanofluids with the volume fraction of particles below the limit of "resolution" of the fluids. In addition, the effect of ζ potentials is against the formation of coagulation and positive to the stability of nanofluids.     

六偏磷酸钠对陶瓷釉料中纳米ZnO分散作用的研究

研究了六偏磷酸钠对纳米ZnO在水体系中和陶瓷釉料体系中的分散作用以及纳米ZnO对陶瓷成品釉面性能的影响.采用沉降实验、粒度分析、釉料流变性、陶瓷成品光泽度和釉料始熔温度测试手段,对含纳米ZnO的水溶液、釉料和陶瓷成品进行了表征.结果表明,在实验条件下,纳米ZnO在水中最佳分散条件为:0.5%六偏磷酸钠,3.0%纳米ZnO,pH为9.在陶瓷釉料中最佳分散条件为:0.5%六偏磷酸钠,4.0%纳米ZnO,pH为9.釉料中含4.0%纳米ZnO的陶瓷制品,光泽度提高5.10%,烧成温度降低约15℃.     

The effect molecular weight of polyol components on shape memory effect of epoxy-polyurethane composites

This paper describes the experimental findings of the study of a series of PU/epoxy composites, which formed interpenetrating networks and have shape-memory properties. The morphological variation for different chemical compositions and the influences of morphology on mechanical performance and shape-memory behavior are discussed. Length and mass fraction of polyethylene glycol (PEG) units are chosen as the key parameters in this study. The molecular weight of PEG was varied from 400 (as such PEG units are unable to crystallize) to 1500, 4000, and 6000, which are crystallizable. It was shown that the crystallization of PEG units is the key parameter, which determines the mechanical performance and shape-memory behavior of PU/epoxy composites in this study. DMTA results show the linear dependence of glass transition temperature and tensile strength, elongation, and other mechanical parameters on the amount of PEG in PU/epoxy composites independently of the amount of PEG unit lengths. The maximal value of shape fixation rate was achieved for 30–40 mass percentage of PEG 4000 (4.5 × 10⁻² s⁻¹ at T_g + 20°C) or PEG 6000(4.1 × 10⁻² s⁻¹ at T_g + 20°C) in PU/epoxy composites.     

混凝试验中效果评判的新方法

通过对两类不同的水源进行混凝试验,发现用混凝后水的浊度来评判混凝效果的方法,对一般水质的水源是有效的,但对某些特殊水质的水源如低温低浊水,或对混凝处理后水质要求较高的场合如反渗透进水,就无法准确找出最佳的混凝剂和混凝条件.因此,提出了用测量矾花(絮凝体)大小及生长速度和泥渣虚度的指标来评判混凝试验效果的新方法,与常用的以混凝后水的浊度来评判混凝效果相比,用此方法更能准确地评判混凝试验效果的优劣.     

New intramolecular effect observed for polyesters: An anomeric effect

A series of polyesters was prepared to evaluate hydrolytic stability as a function of cyclohexyl dibasic acid content. The three cyclohexyl dibasic acids: 1,2; 1,3; and 1,4 were formulated into polyesters with two glycols. The proportion of cis and trans isomers was evaluated via ¹H NMR. The hydrolytic stability of short chain polyesters was evaluated in an acetone/water mixture which solubilized the polyesters to mimic oligoester behavior within a thermosetting polyester coating environment. The rate of hydrolysis was monitored by acid titration and corroborated by GPC. Surprisingly, 1,2-cylohexyl diacid-based polyesters were robust, and 1,3-cyclohexyl diacid-based polyesters were the most susceptible to hydrolysis. Evidently, a 1,2-anchimeric effect for cyclohexyl dibasic acid polyesters was not an important consideration, while the 1,3-cyclohexyl ester interaction was. Consequently, an anomeric effect was proposed. Presented at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 12–14, 2003, in Philadelphia, PA.     

化肥的生态效应

化肥在生产、储存、运输、使用过程中及使用后,对生态环境产生的影响,统称为化肥的生态效应。对生态环境有利的影响,叫化肥的生态正效庆,妨碍生态环境正常发展的,叫化肥的生态负效应。研究化肥的生态效应,并以这些研究成果指导生产实践,可以帮助我们正确认识化肥对人类的贡献与对环境的影响之间的关系。过去,我们过于重视其正效应而忽视了负效应,付出了很大的代价。但在强调可持续发展的今天,我们应关注其负效应,从而将使用化肥的环境代价降至最低水平。     

Notch sensitivity of concrete and size effect part II: Stress state effect

The problem of notch sensitivity of concrete is discussed with the influence of size effect being taken into account. The need to consider the size effect on the tensile strength of concrete was noted. The simple dependence of the critical stress intensity factor K_IC on stress state, specimen and crack geometry, tensile strength and structure of material is found. When analysing the fictitious crack model the fracture zone length is calculated as a function of specimen and crack geometry and structure of the material. The directions of further research are discussed.     

硝酸磷肥在西瓜上的应用效果

硝酸磷肥是一种氮磷复合肥,主要成分是磷酸二钙、硝酸铵、磷酸一铵,次要成分有硝酸钙、磷酸二铵和石膏等。氮素形态包括铵态氮和硝态氮,两者各占1/2,磷素中非水溶性磷约占磷含量的1/2。硝酸磷肥在北方石灰性土壤上对多种作物都有明显的增产效果。为了探讨其在早春小拱棚西瓜上肥料效应及增产效果,我站布置了在双膜小拱棚西瓜上的肥效试验。1　材料与方法1·1　供试土壤试验地块土壤肥力中等,上茬为水稻,排灌条件良好,试验土壤基本理化性状见表1。表1　供试土壤主要理化性状土壤层次/cmpH有机质/(g·kg1)w(N全)/%碱解氮/(mg·kg1)速效P…     

Understanding the detrimental effect of nitrate presence on EBPR systems: effect of the plant configuration

The interaction between enhanced biological phosphorus removal (EPBR) and biological nitrogen removal may result in EBPR failure in full‐scale wastewater treatment plants (WWTPs). This work studies one of the common causes of this failure: the presence of nitrate in the anaerobic phase, which may act as an inhibitor for polyphosphate accumulating organisms (PAO) activity or may activate the competition between PAO and denitrifying bacteria for the carbon source. Several batch experiments were performed with different carbon sources (acetic acid, propionic acid and sucrose) at different nitrate concentrations using PAO‐enriched sludge from two different pilot plants: an anaerobic/aerobic sequential batch reactor (SBR) and an anaerobic/anoxic/aerobic (A²/O) continuous plant. The results imply that the operational conditions of the A²/O pilot plant selected a PAO population capable of i) coexisting with nitrate without an inhibitory effect and ii) outcompeting denitrifying bacteria for the carbon source, in contrast to the SBR pilot plant where nitrate had an inhibitory effect on EBPR. Copyright © 2012 Society of Chemical Industry     

化妆品保湿功效评价

考察了保湿评价前用湿巾清洁与香皂清洁的皮肤预处理方法,以及清洁后对皮肤水分的影响。比较了3种保湿水在使用后不同时问,皮肤水合度和透皮失水的变化,并且对比了不同皮肤类型使用同种保湿水后水合度、透皮失水的变化。得出,保湿水3号短期保湿效果最佳,使用后8h,皮肤水合度由初始的33．2提高到60．7,提高了82．8％,并且对于干燥皮肤保湿效果更好。3种保湿水均能够降低透皮失水值,改善及修复皮肤的屏障功能,且保湿水3号对不同皮肤类型的最终皮肤屏障改善程度一致。     

The effect of gloss on color

A model was developed for the effect of gloss on reflected color, taking the measurement geometry of the color measuring device into account. It considers the total front surface reflectance of a given sample to be independent of gloss and determined only by its refractive index and the angle of the incident beam. Although the total front surface reflectance is fixed, its specular component increases (and the diffuse component decreases) with increasing sample gloss. Therefore, the diffuse reflectance factor measured by a spectrophotometer decreases with sample gloss. In this article, a defined curve was fitted to the measured reflectance factor of black xerographic print samples having a range of gloss values for the 0/45 and diffuse spectrophotometer geometries, and this curve was used to predict the CIELAB color values for samples of the other colors at various gloss levels. The predicted color was compared to the measured color for cyan, magenta, yellow, red, green, and blue images that spanned a wide range of gloss. The RMS color error between the predicted and measured color of all of these images was found to be about 3 CIELAB ΔE* units. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 369–376, 1999     

电解槽阳极效应自动熄灭技术

通过铝电解生产实际,阐述了在铝电解生产中利用电气技术自动熄灭阳极效应的原理和步骤,分析了影响电解槽自动熄灭阳极效应的几种因素,以及采取哪些措施后,更有利于自动熄灭阳极效应。     

PRP燃烧器技术应用效果

分析了PRP燃烧器技术工作原理,综述了PRP燃烧器的性能和优点。PRP燃烧器在太原发电厂的实际应用效果表明,此技术可以解决锅炉燃烧不佳的问题。     

控失型复合肥肥效试验

为研究控失型复合肥在安徽主要农作物上的肥效,在玉米、小麦、水稻上进行了田间试验。结果表明：施用控失型复合肥与普通复合肥比较,玉米、小麦、水稻分别增产13．5％、13．6％和16．8％;施用控失型复合肥的土壤碱解氮、速效磷、有机质均比施用其他试验肥料有所增加。控失型复合肥省工、增效、环保,值得推广应用;