Solubility parameters and solvent affinities for polycaprolactone: A comparison of methods

Intrinsic viscosity measurements were used in combination with the functional solubility parameter (FSP) and Hansen solubility parameter (HSP) fitting methods to determine the solubility parameters (SPs) of polycaprolactone (PCL). Despite using only eight solvents, a simple similarity criteria approach showed that the HSPs and FSPs were good predictors of the relative solvent-PCL affinity compared to HSPs available in the literature and SPs calculated using additive group contribution methods. Three complementary computational methodologies—Conductor-like Screening MOdel for Real Solvents (COSMO-RS), partial solvation parameters (PSPs), and a thermodynamic quantitative structure–property relationship (QSPR) approach—were used to substantiate the relative solvent–PCL affinities revealed by the intrinsic viscosity measurements. The solvent affinities predicted by all three techniques were in good agreement with the trend observed in the experimental intrinsic viscosity data, but the COSMO-RS activity coefficients, ln(γ_PCL), were slightly superior to the PSP and thermodynamic QSPR methods, particularly when incorporating the Elbro free-volume combinatorial correction in the COSMO-RS calculations. As part of this study, the FSP fitting algorithm was modified to obtain the PSPs for PCL in terms of the intrinsic viscosity data, thereby, presenting a promising new way to calculate the PSPs of polymers from empirical solubility and solvent affinity data. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48908.     

Freeze concentration of whey in a falling-film based pilot plant: Process and characterization

Falling-film freeze concentration is a technique for concentration of liquids by freezing the available water in the form of a layer of ice on a refrigerated surface. Processing at low temperatures keeps the organoleptic properties of the initial product. In this study the freeze concentration of whey was investigated as an technological alternative for the use of this byproduct of the dairy industry. Freeze concentration tests were carried out in pilot-scale equipment and the increase in soluble solids content of the whey and the amount and purity of the ice formed were analysed. Electrical conductivity, viscosity and freezing point of the concentrated whey were determined. The concentrate obtained had a solid concentration of up to 21.8 °Brix. The ice formed in the last stage of the freeze-concentration process had a lactose content of 11.3 g/L and protein content of 3.45%. The electrical conductivity of the ice formed increased exponentially to a value of 29.40 mS/cm. Freeze-concentrated whey of 10, 15, and 20 °Brix behaves as a Newtonian fluid in the temperature range of −4 °C-4 °C.     

高压上浆工艺指标的定量定性研究

通过对高压上浆浆液含固率、压出加重率、压出回潮率、压浆力及浆液粘度等工艺指标的分析研究 ,提出了高压力、高浓度和低粘度各指标的量化标志和范围 ,分别分析了压力、浓度、粘度的影响因素 ,并给出了在一定条件下三种工艺指标相应的计算公式。     

部分糊化淀粉浆液黏度与浆液性能相关性分析

探讨部分糊化淀粉浆液黏度对浆液性能影响的规律。以玉米淀粉为原料,采用蒸汽升温方式分别在62℃~67℃制备了6种不同黏度的部分糊化淀粉浆液,对浆液的黏度、糊化度、结晶度、粒径和膨胀势进行测试,并应用SPSS统计软件的相关分析与线性回归分析功能对测试结果进行了相关性分析。结果表明:部分糊化淀粉浆液的黏度与结晶度呈负相关,结晶度随黏度的增大而降低;黏度与平均粒径、膨胀势呈极显著正相关,平均粒径和膨胀势值均随黏度的增加而明显增大;黏度与平均粒径、膨胀势呈明显的线性关系。认为通过相关性分析可以建立起部分糊化淀粉浆液的评价分析方法,运用此方法,可以直观、有效地对部分糊化淀粉浆液黏度性质进行评价分析。     

Effects of alkaline and acid pretreatment on the physical properties and nanostructures of the gelatin from channel catfish skins

The objective of this study was to illustrate the correlation between the physical properties and nanostructure of gelatins made of channel catfish (Ictalurus punctatus) skins. The gelatin samples were first pretreated with sodium hydroxide, acetic acid, or water, and then extracted with hot water before the measurement. Physical properties including the yield of protein, viscosity and textural properties were determined on gelatins obtained with different pretreatment conditions. The acid pretreatment group showed the highest gel strength and protein yield, and a reasonable viscosity. The water pretreatment group showed the lowest values for all of the physical properties. Four samples including water, 0.1 M acid and 0.25 and 1.0 M alkaline-pretreated groups’ nanostructures were then studied using atomic force microscopy (AFM). The AFM images showed that the acid-pretreated gelatin was composed of sponge-like aggregates, while the others showed separated individual aggregates. Annular pores were only found in the alkaline pretreatment group. There was no significant correlation between the diameters of the spherical aggregates and the physical properties; however, the different AFM patterns may relate to the gelatin's physical properties.     

垦西稠油的降粘研究

垦西稠油是超稠油,开采的关键在于降粘。探索了温度、溶剂和乳化剂对垦西稠油的降粘效果。升温降粘法是稀释降粘法和乳化降粘法的基础。温度每升高１０℃,垦西７３１ 井稠油粘度降低在３８％ —５０ ％ 范围。稀释降粘法效果明显,加入５ ％ —１０％ 的芳烃溶剂即可将垦西７３１ 井稠油的粘度降低到可在５２—７８ ℃下顺利开采的程度。而乳化降粘法必须在升温降粘法和（或）稀释降粘法配合下使用。     

无油润滑压缩机润滑油闪点和粘度下降原因分析

分析了聚丙烯装置丙烯循环气体压缩机润滑油的闪点、粘度降低，影响设备运行的原因，并叙述了采取多种改进措施，最后取得了良好效果的情况。     

125I粒子源活度的测量

为了控制粒子源植入组织间实施近距离放射治疗的质量,防范医疗照射事故的发生,按照国际原子能机构1274号技术报告要求,对同一批次(50枚)放射源的10%(5枚)进行检测,并要求测得的粒子源的表观活度与厂家给出值的相对偏差在5%以内.本文介绍了我院临床上使用的125I粒子源(6711型)的活度的测定方法.采用井型电离室测定125I粒子源的空气比释动能率,进而估算出125I粒子源的表观活度(又称等效活度),并对结果进行了分析.结果表明,该批125I粒子源的活度合格率达到80%.     

A Complete Experimental Investigation on The Rheological Behavior of Silver Oil Based Nanofluid

In this study, thermo‐physical properties including thermal conductivity, viscosity, density and specific heat capacity of an oil based nanofluid including silver as to be nanoparticles have been experimentally studied. The results indicate an enhancement in thermal conductivity which was depended on bulk temperature and volume fraction of utilized nanofluids. Viscosity data show a significant increment through volume fraction increasing. In addition, the specific heat capacity and density of nanofluids were studied experimentally and it was found that, all measured rheological properties of these nanofluids, were not in agreement to published correlations.