A STUDY OF NON-NEWTONIAN FLOW AND HEAT TRANSFER OVER A NON-ISOTHERMAL WEDGE USING THE HOMOTOPY ANALYSIS METHOD

The thermoconvective boundary layer flow of a generalized third-grade viscoelastic power-law non-Newtonian fluid over a porous wedge is studied theoretically. The free stream velocity, the surface temperature variations, and the injection velocity at the surface are assumed variables. A similarity transformation is applied to reduce the governing partial differential equations for mass, momentum, and energy conservation to dimensionless, nonlinear, coupled, ordinary differential equations. The homotopy analysis method (HAM) is employed to generate approximate analytical solutions for the transformed nonlinear equations under the prescribed boundary conditions. The HAM solutions, in comparison with numerical solutions (fourth-order Runge-Kutta shooting quadrature), admit excellent accuracy. The residual errors for dimensionless velocity and dimensionless temperature are also computed. The influence of the “power-law” index on flow characteristics is also studied. The mathematical model finds important applications in polymeric processing and biotechnological manufacture. HAM holds significant promise as an analytical tool for chemical engineering fluid dynamics researchers, providing a robust benchmark for conventional numerical methods.     

HOMOTOPY ANALYSIS OF FREE CONVECTION BOUNDARY LAYER FLOW WITH HEAT AND MASS TRANSFER

A steady two-dimensional laminar boundary layer flow of an incompressible viscous fluid over a semi-infinite surface is considered to investigate the accuracy of the homotopy analysis method. The governing coupled nonlinear system of differential equations is solved by means of the HAM approach. Explicit analytical series solutions are obtained and compared with numerical solutions. Good agreement is observed between the numerical results and HAM analytical solutions.     

Successive linearisation analysis of unsteady heat and mass transfer from a stretching surface embedded in a porous medium with suction/injection and thermal radiation effects

In this study, we investigate the application of the new successive linearisation method (SLM) to the problem of unsteady heat and mass transfer from a stretching surface embedded in a porous medium with suction/injection and thermal radiation effects. The governing nonlinear momentum, energy and mass transfer equations are successfully solved numerically using the SLM approach coupled with the spectral collocation method for iteratively solving the governing linearised equations. Comparison of the SLM results for various flow parameters against numerical results and other published results, obtained using the homotopy analysis method (HAM) and Runge–Kutta methods, for related problems indicates that the SLM is a very powerful tool which is much more accurate and efficient than other methods. The SLM converges much faster than the traditional methods like the HAM and is very easy to implement. © 2011 Canadian Society for Chemical Engineering     

The milling effect of a new horizontal attrition milling in the production of (Ti0.7,W0.3)C–Ni cermet

The mechanical alloying (MA) method is a powerful and practical process to fabricate advanced materials with unique properties. Developing an effective milling process to produce high-quality powder suitable for scale-up is one of the main issues for the MA method. This study introduces a new high energy ball milling technique, the horizontal attrition ball milling (HAM). The milling effect of the HAM is superior to that of the conventional planetary and attrition milling techniques in the size reduction of particles (fragmentation) and the impact of milling (mechanical strength). The ultrafine (Ti_0.7,W_0.3)C–Ni cermet powders can be obtained by the HAM since (Ti_0.7,W_0.3)C particle growth is effectively inhibited during the carbothermal reduction. Sintered (Ti_0.7,W_0.3)C–Ni cermet by the HAM has excellent mechanical properties (hardness and fracture toughness). This study demonstrates that the newly designed HAM is a practical method for synthesizing ultrafine ceramic and composite powders appropriate to produce structural ceramics and composites that have excellent mechanical properties.     

采用一批细胞基质同时收获甲肝和麻疹病毒

目的 采用一批细胞基质同时收获甲肝和麻疹病毒。方法 应用甲肝 L-A-1株和麻疹 27D3株,间隔3周先后感染同一批人胚肺二倍体细胞2BS株,待两种病毒同时达到增殖高峰期时收获病毒液（以下简称HAM）,并分别进行病毒滴定、特异性检查、猴体安全性和免疫效果试验。结果HAM的甲肝和麻疹病毒滴度与同批单价甲肝和麻疹疫苗病毒滴度,差异均无显著意义。结论 该方法用于制备甲肝-麻疹联合疫苗,操作简便,省时省力,并可显著降低疫苗生产成本。     

Synthesis and characterization of SSS/HAM/AA terpolymer as a fluid loss additive for oil well cement

A terpolymer comprising of sodium styrene sulfonate (SSS), n‐methylol acrylamide (HAM), and acrylic acid (AA) was synthesized by aqueous free radical copolymerization and evaluated as fluid loss additive (FLA) in oil well cement. In this article, HAM is first introduced in the preparation of FLA as an environment‐friendly monomer, which effectively improves the adhesion and fluid loss control of the terpolymer. The experimental synthesis conditions were optimized by orthogonal experiments. The molecule weight of the terpolymer was determined by gel permeation chromatography. The molecule structure of the synthesized terpolymer was verified by X‐ray photoelectron spectroscopy and Fourier transformer infrared spectrum. The thermal stability of the synthesized terpolymer was tested by thermogravimetry (TG). The structure of the terpolymer aqueous solution was observed by scanning electron microscope. The results show that SSS/HAM/AA has an excellent thermal resistant. The thermal degradation is not obvious before 295.2 °C. Furthermore, the microstructure of SSS/HAM/AA in water conducive to good fluid loss control ability. When the dosage of SSS/HAM/AA is up to 2.0% in fresh water cement slurry, the filtration loss [FL_(HTHP)] can be controlled within 50 mL at 90–150 °C. SSS/HAM/AA has an excellent property of reducing filtration loss. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46266.     

The effect of nonionic monomer HAM on properties of cationic surfactant‐free acrylic/alkyd hybrid emulsion

A series of cationic acrylic/alkyd resin (CPAAR) hybrid emulsions was successfully prepared through surfactant‐free emulsion polymerization, using methacryloxyethyltrimethyl ammonium chloride, methyl methacrylate, butyl acrylate and alkyd resin as reaction monomers. And nonionic N‐hydroxymethyl acrylamide (HAM) of different content was simultaneously incorporated into the CPAAR backbone. The structure of CPAAR copolymer was characterized by Fourier transform infared spectrometer, and then the effect of HAM content on properties of CPAAR emulsions was studied by particle size analyzer, transmission electron microscopy and rheometer. In addition, thermal properties, water absorption and contact angle of CPAAR latex films were also investigated. The results showed that the CPAAR emulsions prepared with 4.9 wt % HAM displayed smallest average particle size of 92.2 nm. As HAM content increased from 0 to 19.6 wt %, the initial viscosity of the emulsions increased from 22.48 to 53 mPa.s. At the same time, the emulsions transferred from Newtonian fluid to pseudoplastic fluid, and a transition from viscous liquid to elastic liquid was also detected. Meanwhile, the degradation temperature at 5% weight loss increased by 30.59°C. In addition, with increasing HAM content from 0 to 4.9 wt %, the water absorption and surface free energy of films increased by 4.42% and 5.02 mJ m^?2, respectively. However, the water absorption and surface free energy kept almost invariable with further increase in HAM content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41406.     

Selective Ruthenium‐Catalyzed Hydroaminomethylation of Unsaturated Oleochemicals

Rhodium‐catalyzed hydroaminomethylation (HAM) is recently described as an innovative way to functionalize triglycerides. In the search to reduce production costs, rhodium is sought to be replaced by ruthenium whose price is currently more than 20 times lower. In this study, HAM of unsaturated oleochemicals using ruthenium precursors is proceeded under phosphine‐free conditions. The experimental conditions are optimized by changing the nature of the solvent, the reaction temperature, and the CO/H₂ pressure. While rhodium leads to good catalytic activity and low chemoselectivity (mixture of hydroxyl and amino groups), ruthenium proves to be less active but more chemoselective as amino‐substituted products are mainly formed. Of interest, HAM of methyl 10‐undecenoate (MU) occurs in a highly chemo‐ and regioselective fashion using acetonitrile as solvent. Practical Applications: Selective Ru‐catalyzed hydroaminomethylation can be implemented on an industrial scale for the conversion of unsaturated oleochemicals into amines. This finding is of importance as the obtained amino‐products can be used in many industrial areas such as surfactants, polymers, or lubricants.     

甲肝麻疹二联活疫苗猴体安全性研究

目的　观察甲肝麻疹二联活疫苗 (简称HAM)的安全性。方法　选用 1.5～ 4 .5kg抗甲肝病毒抗体(HAVAb)及麻疹血凝抑制抗体 (MVH1Ab)皆阴性 ,SGPT正常的健康恒河猴 4 4只。麻疹嗜神经毒力试验分 3组 ,HAM及MV分别接种于 5只及 10只猴丘脑内 ,空白对照 4只 ;甲肝疫苗嗜肝毒力试验分 5组 ,HAM、HA和MV各分别接种于 5只猴的静脉内。进行SGPT、中枢神经 (CNS)和肝穿病理学检查 ,以及抗HAVAb和MVH1Ab测定。结果　第 1组所有实验猴及空白对照猴其临床观察均未发生由MV引起的神经症状 ,CNS组织学检查未见由MV引起的麻疹性脑脊髓的病变。第 2组全部猴均无SGPT异常升高和病毒性肝炎的病理改变。结论　该HAM与对照单价活疫苗相同 ,具有可靠的安全性     

OPTIMAL POLICIES OF A LIQUID CHROMATOGRAPHY SEPARATION

A simulation model of a chromatographic separation is used to define an objective function representing the system performance, which is oplimized by transforming an optimal control problem into a nonlinear programming problem. The decision variables of the problem are the injection time period, the cycle time and the switching times for the production cut of each key component. The objective function is either the product recovery to be maximized, or the off-cut collection to be minimized.

Two numerical examples are presented in order to illustrate this' approach: the separation or a binary mixture and the purification of one key component in a ternary mixture. In each case, an extensive sensitivity analysis of the optimal solution is presented.     

Electrospun Fiber-Coated Human Amniotic Membrane: A Potential Angioinductive Scaffold for Ischemic Tissue Repair

Cardiac patch implantation helps maximize the paracrine function of grafted cells and serves as a reservoir of soluble proangiogenic factors required for the neovascularization of infarcted hearts. We have previously fabricated a cardiac patch, EF-HAM, composed of a human amniotic membrane (HAM) coated with aligned PLGA electrospun fibers (EF). In this study, we aimed to evaluate the biocompatibility and angiogenic effects of EF-HAM scaffolds with varying fiber thicknesses on the paracrine behavior of skeletal muscle cells (SkM). Conditioned media (CM) obtained from SkM-seeded HAM and EF-HAM scaffolds were subjected to multiplex analysis of angiogenic factors and tested on HUVECs for endothelial cell viability, migration, and tube formation analyses. All three different groups of EF-HAM scaffolds demonstrated excellent biocompatibility with SkM. CM derived from SkM-seeded EF-HAM 7 min scaffolds contained significantly elevated levels of proangiogenic factors, including angiopoietin-1, IL-8, and VEGF-C compared to plain CM, which was obtained from SkM cultured on the plain surface. CM obtained from all SkM-seeded EF-HAM scaffolds significantly increased the viability of HUVECs compared to plain CM after five days of culture. However, only EF-HAM 7 min CM induced a higher migration capacity in HUVECs and formed a longer and more elaborate capillary-like network on Matrigel compared with plain CM. Surface roughness and wettability of EF-HAM 7 min scaffolds might have influenced the proportion of skeletal myoblasts and fibroblasts growing on the scaffolds and subsequently potentiated the angiogenic paracrine function of SkM. This study demonstrated the angioinductive properties of EF-HAM composite scaffold and its potential applications in the repair and regeneration of ischemic tissues.     

高固含量BA/MMA/HAM乳液乳胶粒的影响因素

合成了固含量 70 %以上的高固含量BA/MMA/HAM共聚物乳液。探讨了单体配比、引发剂、链转移剂的用量、反应温度对BA/MMA/HAM高固含量共聚物乳液乳胶粒的影响     

INFLUENCE OF HEAT TRANSFER IN THE SQUEEZING FLOW BETWEEN PARALLEL DISKS

This article addresses the squeezing flow and heat transfer between parallel disks when one disk is impermeable and the other is porous. Appropriate similarity transformations are invoked to convert the partial differential equations into ordinary ones. Expressions for velocity and temperature fields have been obtained by homotopy analysis method (HAM). The effects of embedding parameters such as squeeze number (S), Hartman number (M), Prandtl number (Pr), and Eckert number (Ec) are analyzed through graphs for the velocity and temperature profiles and tables for skin friction coefficient and local Nusselt number. It is observed that the series solutions are convergent only at third-order of approximation. The obtained results for velocity are also compared with the homotopy perturbation method (Domairry and Aziz, 2009).     

A SEQUENTIAL PROCEDURE WITH ELIMINATION FOR PARTITIONING A SET OF NORMAL POPULATIONS HAVING A COMMON UNKNOWN VARIANCE

We consider the problem of partitioning a set of normal populations, with respect to a control population, into two subsets according to their unknown means, under the indifference zone formulation. For this problem Tong (1969) constructed a two-stage and purely sequential procedures and recently Datta and Mukhopadhyay (1998) have considered various multistage methodologies emphasizing the second-order asymptotics. However, all these methodologies adopt a vector-at-a-time sampling approach and lack the desirable feature of eliminating treatments from further sampling at an earlier stage. We propose an elimination type sequential procedure using the Paulson's (1964) elimination idea and design a sampling methodology which eliminates “superior” and “inferior” treatments during the sampling, thereby reducing the average sample size considerably. Theoretical results are obtained to show that the proposed elimination-type procedure maintains the probability of correct partition above a pre specified level. The proposed procedure is studied and compared via the Monte Carlo simulation studies with other competitive procedures known in the literature, under both the LFC and a few non-LFC configurations. The elimination-type procedure is found to be vastly more efficient than its competitors in terms of average sample size.     

不同代次S191株麻疹病毒HA基因的序列分析

目的　考察麻疹S191疫苗株在长期传代过程中HA基因的变化 ,以确定用于生产的最佳代次。方法　对麻疹S191疫苗株鸡胚细胞系 (CEC) 2 0、30代病毒株及S191株羊膜系病毒株 (强毒 )HAM42的血凝蛋白 (HA)基因进行RT—PCR ,克隆到PUC质粒后进行测序。结果　 2 0代和 30代疫苗的HA基因的 185 4个碱基序列中未出现核苷酸的变化 ,但二者与HAM42株相比有两个核苷酸的变化 ,分别在 15 17和 1799位 ,并导致 5 0 6位的Gly变为Asp ,6 0 0位的氨基酸由Glu变为Val。结论　麻疹病毒的减毒株与强毒株存在差异。而麻疹减毒株在鸡胚细胞的长期传代中 ,HA基因未出现明显变化 ,没有出现抗原漂移 ,30代毒株与 2 0代毒株是一致的     

ADAPTIVE CONTROL OF A BATCH REACTOR

A globally stable adaptive predictive control system (APCS) is evaluated by application to a simulated PVC batch reactor. The reactor is run under APCS control with the objective of either temperature setpoint tracking or constant reaction rate. The batch nature of this system makes it possible to learn about the physical problem from successive runs. This knowledge is incorporated into the control strategy to improve the performance of the reactor. The problem of excessive manipulation of the control variable has been recognized and resolved by using control weighting. Performance of the adaptive technique is compared with previous results using self-tuning and PID control of the same reactor. APCS provides good, robust control despite the nonlinear dynamics of the system.     

乳液型无纺布用粘合剂的研究

研究了聚合单体、乳化剂、交联剂、引发剂、聚合工艺对产品性能及生产稳定性的影响。实验表明:以醋酸乙烯酯(VAC)和丙烯酸丁酯(BA)为单体,N-羟甲基丙烯酰胺(HAM)和衣康酸(ITA)为交联剂,以壬基酚聚氧乙烯醚磺基琥珀酸盐(OS)和壬基酚聚氧乙烯醚(OP)为乳化剂,以过硫酸铵(APS)为引发剂,投料质量比为VAC∶BA∶HAM∶ITA∶OS∶OP∶APS=85∶15∶3∶2∶2.5∶1.5∶0.8,采用预乳化滴加工艺,反应温度为75℃时制得的乳液,用泡沫涂布法生产无纺布,效果良好且成本低廉。     

ON THE ROBUST PREDICTION AND INTERPOLATION OF TIME SERIES IN THE PRESENCE OF CORRELATED NOISE

Abstract. We consider the problem of predicting and interpolating linearly a time series which can be represented as the sum of a model process with known spectral density and a noise process. The spectral density of the noise process is unknown with the exception of an upper bound for its integral. Some partial information of quite general kind about the cross spectral density of model and noise is available. We prove the existence of a robust predictor which minimizes the maximal mean-square error, where the maximum is taken over all spectral densities which may arise from the circumstances described above as spectral density of the predicted time series. An analogous result holds for the related interpolation problem. We describe how to derive the minimax robust predictor and interpolator in concrete situations. The method is illustrated by determining the robust predictor explicitly for three examples where model and noise may be arbitrarily, only causally or not at all correlated.     

HIGHER-ORDER ASYMPTOTIC PROPERTIES OF A WEIGHTED ESTIMATOR FOR GAUSSIAN ARMA PROCESSES

Abstract. Let { X _t } be a Gaussian ARMA process with spectral density f _θ(Λ), where θ is an unknown parameter. To estimate θ, we propose an estimator θC_w of the Bayes type. Since our standpoint in this paper is different from Bayes's original approach, we call it a weighted estimator. We then investigate various higher-order asymptotic properties of θC_w. It is shown that θC_w is second-order asymptotically efficient in the class of second-order median unbiased estimators. Furthermore, if we confine our discussions to an appropriate class D of estimators, we can show that θC_w is third-order asymptotically efficient in D . We also investigate the Edgeworth expansion of a transformation of θC_w. We can then give the transformation of θC_w which makes the second-order part of the Edgeworth expansion vanish. Finally we consider the problem of testing a simple hypothesis H:θ=θ_o against the alternative A:θ#θ_o. For this problem we propose a class of tests δ_A which are based on the weighted estimator. We derive the X ² type asymptotic expansion of the distribution of S (ζδ_A) under the sequence of alternatives A n :θ=θ_o+ε n ^1/2, ε > 0. We can then compare the local powers of various tests on the basis of their asymptotic expansions.     

ESTIMATION OF COEFFICIENTS OF TIME SERIES REGRESSION WITH A NONSTATIONARY ERROR PROCESS

Abstract. We treat a problem of estimating unknown coefficients of a time series regression when the variance of the error changes with time, i.e. when a process which the error term obeys is nonstationary. First, we show the weak consistency of the ordinary least squares estimator for the coefficients of a polynomial regression under some assumptions on the covariance structure of the error process. Next, we propose a nonparametric method for estimating the variance of the error process and a weighted least squares estimator of the regression coefficients, which is constructed by using the estimator of the variance. We investigate statistical properties of our proposed estimator in the following way. We consider the prediction of a future value of a linear trend by using our proposed estimator and evaluate its prediction error. By simulation studies, we compare the prediction error of the predictor constructed by using our proposed estimator with the prediction errors obtained for other estimators including the ordinary least squares estimator when the variance of the error process increases with time and the sample sizes are small. As a result, our proposed estimator seems to be reasonable.