微波改性玉米淀粉的制备及其粘度性质的研究

采用微波对玉米淀粉进行辐照,运用Brabender粘度计对微波改性玉米淀粉的粘度曲线进行了测定,考察了不同微波时间、微波功率及微波时淀粉的水分含量对淀粉糊粘度性质的影响,并与原淀粉进行比较。结果发现:随着微波时间的延长,功率的增大,淀粉水分含量的增加,淀粉峰值粘度均下降,凝沉性降低,热糊稳定性和冷糊稳定性都有不同程度的增加,糊化温度也有所提高。其中水分对淀粉性质的影响最为显著。

非糯性大米粉糊粘度性质的研究

本文用Brabender粘度计研究了多种粳、籼米粉在不同糊浓度、pH值、蔗糖、盐存在下 。

无机盐对十二烷基硫酸钠溶液粘度性质的影响

在(303.2±0.1)K条件下,测定添加硫酸镁、硫酸钠、氯化钠的十二烷基硫酸钠(以下简称SDS)溶液对原SDS溶液的相对粘度-浓度曲线.测定结果表明:无机盐对SDS溶液有显著的增粘作用,并且当盐的浓度达到一定程度时会与SDS作用形成沉淀,增粘作用达到一个极限.这些结果可以用表面活性剂溶液中胶团的结构、离子与胶团的相互作用和活度积效应等进行解释.

聚乙烯胺盐酸盐水溶液的粘度性质研究

通过聚丙烯酰胺的Hofmann降级重排反应制备聚乙烯胺盐酸盐,研究了聚乙烯胺盐酸盐水溶液的粘度性质。研究表明,浓度和pn值对聚乙烯胺盐酸盐水溶液的粘度有很大影响,其水溶液的比浓粘度在pH值为4左右时达到极值;聚乙烯胺盐酸盐的特性粘数明显高于其原料聚丙烯酰胺的特性粘数,分子量对特性粘数的影响十分明显,而胺化度对特性粘数的影响并不显著。

七山粘米粉糊粘度性质的研究

通过对七山粘米粉糊在不同条件和配料下粘度曲线的测定 ,研究了粉乳浓度、pH值、蔗糖量、食盐量、磷酸二氢钠、单甘酯等对七山粘米粉糊粘度性质的影响 ,对进一步开发七山粘米粉的应用有一定的意义。

高粘度十二烯基琥珀酸淀粉钠理化性质的研究(Ⅰ)——糊的性质

采用Brabender粘度仪、分光光度计、旋转粘度计等现代分析仪器 ,研究了高粘度十二烯基琥珀酸淀粉钠糊的流变性质、糊的粘度性质、糊的凝沉性质、糊的透明度和糊的冻融稳定性等理化性质 。

发动机润滑油的性能与节油

发动机润滑的性能对汽车运行燃油经济性影响很大，表1～表3列出了改变发动机润滑油和齿轮油的粘度性质和减磨性能，汽车在不同行驶条件下可能取得的节油率（％）。

Fracture prediction in non-isothermal viscous pressure bulging of aluminum alloy sheet using ductile fracture criterion

The failure of AA3003 aluminum alloy sheet metal was predicted for non-isothermal viscous pressure bulging (VPB). Utilizing the coupled thermo-mechanical finite element method combined with ductile fracture criterion, the calculations were carried out for non-isotherm VPB at various temperatures and the influences of the initial temperature of viscous medium on failure mode of bulge specimens were investigated. The results show that the failure modes are different for the non-isothermal VPB with different initial temperatures of viscous medium. For the non-isothermal VPB of AA3003 aluminum alloy sheet with initial temperature of 250 ℃, when the initial temperature of viscous medium ranges from 150 to 180 ℃, the formability of sheet metal can be improved to a full extent. The validity of the predictions is examined by comparing with experimental results.

Micromixing Efficiency of Viscous Media in Micro-channel Reactor

Micromixing efficiency of viscous media in Y-type micro-channel reactor was studied by using iodide-iodate test reaction as working system.Experiments were carried out in water-glycerin mixtures with 7 different viscosities.The experimental results showed that segregation index of the micro-channel reactor increases with the decrease of volumetric flow rate and the increase of solution viscosity.Based on the incorporation model,the micromixing time tm of the micro-channel reactor was estimated in the range of 10-4-10-3s at different viscosities,which indicated that the micro-channel reactor possesses a much better micromixing performance compared to the stirred tank(tm=0.02-0.2s).

A Mass Transfer Model for Devolatilization of Highly Viscous Media in Rotating Packed Bed

A mass transfer model for devolatilization process of highly viscous media in rotating packed bed(RPB) was developed based on penetration theory and mass conservation.Before establishing the model,some mass transfer experiments of thin film were conducted in a designed diffusion cell including vacuum and feeding system. In this study,acetone was used as the volatile organic compound(VOC) and syrup as the highly viscous media.The thickness of thin film was changed by using different liquid distributor.It was found that bubbling played an important role in the devolatilization.The correlation of diffusion coefficient of acetone in highly viscous dilute solution was proposed.The relative error between predicted and experimental data was within the range of ± 30% for diffusion coefficient of acetone in syrup.A comparison of experimental data of RPB with model indicated that the relative error was within ± 30% for efficiency of acetone removal.

Measurement of thermal conductivity,viscosity and density of ionic liquid [EMIM][DEP]-based nanofluids

This article studied experimentally the effect of multi-wall carbon nanotubes （MWCNTs） on the thermo physical properties of ionic liquid-based nanofluids. The nanofluids were composed of ionic liquid, 1-ethyl-3- methylimidazolium diethylphosphate [EMIM][DEP], or its aqueous solution[EMIM][DEP]（1） ＋ H20（2） and MWCNTs without any surfactants. The thermal conductivity, viscosity and density of the nanofluids were mea- sured experimentally. The effects of the mass fraction of MWCNTs, temperature and the mole fraction of water on the thermo physical properties of nanofluids were studied. Results show that the thermal conductivity of nanofluids increases within the range of 1.3%-9.7% compared to their base liquids, and have a well linear depen- dence on temperature. The viscosity and density of the nanofluids exhibit a remarkable increase compared with those of the base liquids. Finally, the correlation of the effective thermal conductivity and viscosity of the nanofluids was made using the models in the literatures.

Key Variables Explaining Soil Organic Carbon Content Variations in Croplands and Non-Croplands in Chinese Provinces

Soil organic carbon (SOC) plays an important role in global carbon cycles.Large spatial variations in SOC contents result in uncertain estimates of the SOC pool and its changes.In the present study,the key variables explaining the SOC contents of croplands (CPs) and non-croplands (NCPs) in Chinese provinces were investigated.Data on SOC and other soil properties (obtained from the Second National Soil Survey conducted in the late 1970s to the early 1990s),climate parameters,as well as the proportion of the CP to the total land area (Pcp) were used.SOC content variations within a province were larger than those among provinces.Soil clay and total phosphorus content,ratio of annual precipitation to mean temperature,as well as Pcp were able to explain 75% of the SOC content variations in whole soil samples.Soil pH,mean temperature during the growing season from May to October,and mean annual wind velocity were able to explain 63% of the SOC content variations in NCP soils.Compared with NCP soils,CP soils had lower SOC contents,with smaller variations within and among provinces and lower C/N ratios.Stepwise regression showed that the soil clay content was a unique factor significantly correlated with the SOC content of CP soils.However,this factor only explained 24% of the variations.This result suggested that variables related to human activities had greater effects on SOC content variations in CP soils than soil properties and climate parameters.Based on SOC contents directly averaged from soil samples and estimated by regression equations,the total SOC pool in the topsoil (0-20 cm) of China was estimated at 60.02 Pg and 57.6 Pg.Thousands of years of intensive cultivation in China resulted in CP topsoil SOC loss of 4.34-4.98 Pg.

Evaluation of Feed and Feeding Regime on Growth Performance, Flesh Quality and Fecal Viscosity of Atlantic Salmon(Salmo salar L.) in Recirculating Aquaculture Systems

The effects of different feeds and feeding regimes on growth performance, flesh quality and fecal viscosity of Atlantic salmon （Salmo salar L.） in recirculating aquaculture systems （R.AS） were investigated. Fish （initial body weight of 1677 g＋ 157 g） were fed with four commercial feeds （Nosan salmon-NS, Aller gold-AG, Skretting salmon-SS and Hart ye-HY） in two feeding regimes （80% and 100% satiation） for 78 d. The results showed that salmon specific growth ratio （SGR） and weight gain ratio （WGR） were significantly affected by feed type and feeding regime （P〈0.05）. Feed conversion ratio （FCR） varied between 0.93 and 3.40, which was significantly affected by feed type （P〈0.05）, and slightly improved with increased satiation degree. The activities of digestive enzymes including protease, lipase and amylase were also significantly affected by feed type and feeding regime （P〈0.05）, increasing with satiation degree. Flesh qualities for vitamin E, hydroxyproline （HYP）, liquid loss and muscle pH among all groups showed significant differences （P〈0.05）, ranging from 26.67 to 29.67, while no obvious difference was found in flesh color. Fecal viscosity for different treatments showed no significant difference, though improvement was found in 100% satiation group. From present experiment, it was concluded that both feed type and feeding regime can affect the important quality attributes of Atlantic salmon.

VISCOSITY BEHAVIOR OF PS/TOLUENE SOLUTION IN DILUTE AND EXTREMELY DILUTE CONCENTRATION REGION

The influences of both the volume of PS/toluene solution in the Ubbelohde viscometer and the precision of the time measuring on the viscosity behavior in dilute and extremely dilute concentration region are investigated. It was found that the influence of the former can neglect, but that of the latter is so prominent that the data fluctuate bitterly and linearity of the curve of the reduced viscosity vs. concentration (hsp/c^c) becomes too bad to obey the Huggins equation down to the extremely dilute region, despite the error of the flow times Dt 0.2s, which is permitted by the conventional method of viscosity measurement. Through strict mathematical analyses, it was found that the error (E) of the reduced viscosity is in proportion and inverse proportion to Dt and concentration c, respectively. So the less the concentration, the more the error is. Consequently, a lowest concentration limit cL corresponding to given experimental error may exist and it will be meaningless for further operation below cL because of the great fluctuation of the data. Therefore, it needs to seriously reconsider the application of the conventional method of Ubbelohde viscosity measurement in the extremely dilute polymer solution under traditional conditions because of the great influence of the experimental error.

The effect of curing temperature on the properties of shrinkage-compensated binder

The effects of curing temperature on the expansive effectiveness, strength, hydration degree, and microstructure of shrinkagecompensated binder were studied. The results showed that under the standard curing temperature (20℃), most crystalline ettringite grows in pores, which makes less contribution to the expansion of paste than gelatinous ettringite blended with C-S-H gel. An elevated curing temperature (40℃) promotes the hydration rate of expansive agent and cement. However, quickly developing strength of paste limits its expansion. The pore structure of hardened paste under moderate curing condition is the densest one among all the pastes cured at different temperatures due to the filling effect of crystalline and gelatinous ettringite. Under a high curing temperature (60℃), the formation of massive stick-like ettringite leads to excessive expansion at early hydration age. Some ettringite decomposes at sustainable high temperature, which decreases the restricted expansion rate of paste at a late age. Appropriate volume expansion is benefit to the improvement of pore structure of hardened paste by reducing large pores.

Joint Multifractal Analysis of Scaling Relationships Between Soil Water-Retention Parameters and Soil Texture

Soil water-retention characteristics at measurement scales are generally different from those at application scales, and there is scale disparity between them and soil physical properties. The relationships between two water-retention parameters, the scaling parameter related to the inverse of the air-entry pressure （avG, cm- 1） and the curve shape factor related to soil pore-size distribution （n） of the van Genuchten water-retention equation, and soil texture （sand, silt, and clay contents） were examined at multiple scales. One hundred twenty-eight undisturbed soil samples were collected from a 640-m transect located in Fuxin, China. Soil water-retention curves were measured and the van Genuchten parameters were obtained by curve fitting. The relationships between the two parameters and soil texture at the observed scale and at multiple scales were evaluated using Pearson correlation and joint multifractal analyses, respectively. The results of Pearson correlation analysis showed that the parameter c^vG was significantly correlated with sand, silt, and clay contents at the observed scale. Joint multifractal analyses, however, indicated that the parameter ~vG was not correlated with silt and sand contents at multiple scales. The parameter n was positively correlated with clay content at multiple scales. Sand content was significantly correlated with the parameter n at the observed scale but not at multiple scales. Clay contents were strongly correlated to both water-retention parameters because clay content was relatively low in the soil studied, indicating that water retention was dominated by clay content in the field of this study at all scales. These suggested that multiple-scale analyses were necessary to fully grasp the spatial variability of soil water-retention characteristics.

Crude-oil hydrocarbon composition characteristics and oil viscosity prediction in the northern Songliao Basin

Crude oil hydrocarbon composition characteristics and oil viscosity prediction are important bases in petroleum exploration. A total of 54 oil/heavy-oil samples and 17 oil sands were analyzed and quantified using both comprehensive 2D gas chromatog raphy （GCxGC） and comprehensive 2D gas chromatography/time-of-flight mass spectrometry （GCxGC/TOFMS）. The results show that crude oil in the West slope is mainly heavy oil and its hydrocarbon composition is characterized overall by paraf fins 〉 mono-aromatics 〉 naphthenes 〉 non-hydrocarbons 〉 di-aromatics 〉 tri-aromatics 〉 tetra-aromatics. Aromatics are most abundant and non-hydrocarbons are least abundant, whilst content differences among paraffins, naphthenes, aromatics, and non-hydrocarbons are less than 15%. There are two types of heavy oil, secondary type and mixing type. Biodegradation is the main formation mechanism of heavy oil. Biodegradation levels cover light biodegradation, moderate biodegradation, and se- vere biodegradation. With increasing biodegradation, paraffin content decreases while contents of aromatics and non- hydrocarbons increase. In contrast, naphthene content increases first and then decreases with increasing biodegradation. In se- vere biodegradation stage, naphthenes decrease more quickly than aromatics and non-hydrocarbons. This provides a new method for studying oil/heavy-oil biodegradation mechanism and biodegradation resistance of different hydrocarbons at dif- ferent biodegradation stages. In the Longhupao-Daan terrace and Qijia-Gulong depression, most crude oil is conventional oil. Its composition is dominated by paraffins with the lowest content of aromatics. In some casual oil wells from the Long- hupao-Daan terrace, crude oil from Saertu oil reservoirs is moderately biodegraded whereas crude oil from Putaohua oil reser voir is lightly biodegraded. Chemical parameters using saturate hydrocarbons and aromatics are usually not suitable for deter mining organic type and thermal maturity of biodegraded oil, especially of moderately or severely biodegraded oil, whilst Ts/（Ts＋Tm） ratio can be used to determine thermal maturity of both conventional crude oil and heavy oil.