Mixture Design Approach in Wall Material Selection and Evaluation of Ultrasonic Emulsification in Flaxseed Oil Microencapsulation

Flaxseed oil, sensitive to oxidation, was systematically microencapsulated with six triple wall materials combinations [carbohydrate (maltodextrine and two different modified starches (N-Lok® and HiCap® 100)); protein (sodium caseinate, whey protein concentrate); and Arabic gum] for the highest microencapsulation efficiency and oxidation stability. Proportions of the triple wall materials were optimized in mixture design using the quadratic model. Effects of Ultra-Turrax and ultrasonic emulsifications on microencapsulation efficiencies were additionally characterized in the optimized wall material combinations. The microcapsules produced were investigated for particle size distribution, moisture content, water activity, bulk density, and oxidative stability. Results showed that the combination of modified starch (Hi-Cap® 100)/Arabic gum/whey protein concentrate (4/0/1, w/w/w) provided the highest efficiency in flaxseed oil microencapsulation. However, the only successful combination in preventing flaxseed oil oxidation was maltodextrine/Arabic gum/whey protein concentrate (4/0/1, w/w/w). The microcapsules produced by ultrasonic emulsification had higher microencapsulation efficiency than that of Ultra-Turrax emulsification.     

A critical assessment of the Jastrzebski interface condition for the capillary flow of pastes, foams and polymers

This paper presents a review of unusual apparent slip effects in capillary flow rheometry. Many cases of paste, foam and polymer capillary flow have been reported where the classic analysis of Mooney has yielded unviable flow curves and apparent slip velocities; often the analysis of Jastrzebski has been used as an alternative and sometimes as the analysis of first choice. It is shown that the recently developed Tikhonov regularization method of Mooney analysis can be used to yield viable results for some of the cases where the classic Mooney analysis could not. All of the problematic foam and polymer results found in the literature were resolved, as well as some of the problematic paste results. It is shown that the use of the Jastrzebski interface condition, relating apparent slip to capillary radius, yields incorrect flow curves and apparent slip velocities. It is proposed that further research is required to understand the capillary flow of paste which does not conform to the classic Mooney analysis. In the absence of any physical grounding for the Jastrzebski interface condition, it is recommended that it should no longer be used.     

Soret-‘shifted’ dew-point temperatures for surfaces exposed to hydrocarbon vapors dilute in compressed nitrogen

Soret-driven species transport causes concentration non-uniformities in the immediate vicinity of ‘cold’ surfaces immersed in undersaturated vapor-containing streams. These concentration non-uniformities, in turn, alter corresponding condensation onset temperatures, often by as much as 30 K (i.e., ca. 3%) in previously studied, near-atmospheric pressure combustion systems [see, e.g., Rosner, D.E. and Nagarajan, R., 1985. Chemical Engineering Science 40 (2), 177]. Because high-pressures often cause remarkable increases in the relevant binary Soret factor, α_T,12, we investigate here the importance of these vapor phase ‘transport’ effects for ‘compressed’ N₂ streams containing dilute quantities of an alkane: C₁₂H₂₆ (n-dodecane) or C₈H₁₈ (n-octane). We invoke the virial equation of state (VES) to predict gas phase non-ideality, and its appreciable effect on previously available ideal gas Soret factors. Our illustrative numerical results, valid for, say, nominally 1000 K N₂ streams up to pressures of over 100 atm, reveal that high-pressure Soret ‘shifts’ in T_dp can amount to ca. 80%, even at surface temperatures above the equilibrium freezing points of these condensates. We conclude that these high-pressure vapor phase transport phenomena will not only influence the interpretation of such hot gas/‘cold’ surface ‘dew-point’ measurements, they will significantly raise the temperatures at which containment or immersed surfaces must be maintained to avoid the ravages of corrosive or insulating inorganic condensates [Rosner, D.E., Chen, B.K., Fryburg, G.C., Kohl, F.J., 1979. Combustion Science and Technology 20, 87; Rosner, D.E., 1988a. Invited paper, Benjamin G. Levich Memorial Issue of Journal of Physico-Chemical Hydrodynamics 10 (5/6), 663]. In principle, the present theory could itself be used to study the pressure dependence of the binary Soret factor—at least for systems with well-characterized saturation vapor pressures.     

储气库注气管道选用研究

为了确保储气库注气管道系统安全可靠,保证生产和安全,结合国内外标准相关要求,从石油天然气行业自身特点系统分析了高压注气管道选择的影响因素。通过本文分析可知采用GB 50350《油气集输设计规范》对储气库注气管道进行选择及校核,符合设计要求。     

棉花秸秆草砖房施工技术研究

研究了将农业废弃秸秆-棉花秸秆压制成棉花秸秆草砖,并将其通过砌筑建成草砖建筑,探讨其作为砌筑建房的墙体材料的施工工艺及技术措施,可为棉花秸秆草砖在农村修建"绿色、环保、节能"建筑,提供理论依据,并为我国的农作物秸秆资源循环再利用探索出一条经济、适用、环保的途径。     

Application of ECT to solid concentration measurements during granular flow in a rectangular model silo

The paper presents results of concentration changes in cohesionless sand during dynamic mass flow in a rectangular model silo composed of a bin and hopper. Electrical capacitance tomography (ECT) was used. Sensors were located outside the silo along both the periphery and height. Local horizontal one-dimensional and cross-sectional two-dimensional evolutions of solid concentrations in dry sand during silo discharge were determined. The first ones were estimated from the raw data and the latter were obtained with the aid of the reconstructed data using a Linear Back Projection algorithm (LBP) to solve an inverse problem. Experiments in a model silo were carried out with two different initial sand densities and wall roughness grades. The measured results with ECT were compared with corresponding ones obtained with a Particle Image Velocimetry (PIV) method.     

观念和建筑 天津泰达开发区司法服务中心设计

文章阐述了天津泰达司法服务中心的建筑设计理念,其中所体现的纯粹理性指引下的逻辑性统辖着建筑内在的技术、功能布置以及外部形象,反映出人的观念对建筑的影响。     

满山香子多糖的膜分离研究

研究以满山香子为原料提取多糖的过程及工艺。利用超滤膜分离装置进行满山香子多糖的分离,对影响超滤的工艺条件,如压力、温度、时间进行考察,确定最佳的提取条件:满山香子∶水=1∶20,提取温度80℃,提取时间2h。提取物的多糖含量5.65%,超滤后的提取物中多糖含量达到80.29%,提取物得率为1.19%。