Microbiological, physicochemical and sensory quality of maple syrup aseptically packaged in paper-based laminate

Quality of maple syrup packaged in paper-based laminate at 82°C or room temperature (25°C) was evaluated and compared to a reference syrup packaged in glass bottles stored at 4°C. to prevent microbial growth and blown containers, maple syrup must be heated at 82°C before packaging. Significant pH decrease related to storage temperature was similar to the observation of other authors for glass bottles and cans. Syrup in laminate cartons stored at 4°C, had higher transmittance measurements with time, but at higher storage temperatures, browning effect related to caramelization of sugars balances this transmittance increase. Changes in invert sugar level were significant only in syrup packaged in laminate at 25°C and stored at 23°C and 37°C and were related to the microbial growth. Physicochemical changes were not large enough to affect the overall quality of the product. 'Burnt sugar' off-flavour was detected for samples stored at 37°C. Packaging maple syrup in paper-based laminate at 82°C is an economic alternative to glass bottles, while maintaining a good quality product.     

氯化铵法制取活性氧化锌的工艺研究

介绍了用氯化铵浸取法制备活性氧化锌的新工艺，产品各项技术经济指标均达到部标准，适应性强，工艺简单，锌回收率８７．１％以上。     

Physical properties of some organophosphazene copolymers. I. Structural aspects, transition temperatures, and stress-strain isotherms of the cross-linked networks

Analysis of several poly(organophosphazene) copolymers with variedmeta- andpara-substituted phenoxy repeat units indicated that the copolymers had random sequences, with compositions very close to the equimolar feed ratios used in their synthesis. DSC measurements indicated that they were semicrystalline in spite of this randomness. Networks prepared by cross-linking these copolymers were studied in elongation above their melting points, and stress-strain isotherms thus obtained showed the presence of strain-induced crystallization. Raising the temperature decreased their values of the modulus, presumably by melting some of these crystallites. Swelling the networks also decreased their values of the modulus (at least partly because of solvent-induced depression of the melting point) and decreased their values of the elongation at rupture (presumably because of the stretching-out of the chains by the imbibed solvent prior to the elongation measurements).     

离子减薄诱发的Zr65Al7.5Ni10Cu17.5块状非晶晶化相的相变

用透射电子显微镜研究了锆基块状非晶合金晶化行为，对分别经双喷电解减薄加离子减薄和单纯双喷电解减薄制备的电镜样品进行观察分析，发现离子减薄会导致该合金晶化亚稳相的转变。     

Role of some rare earth (RE) ions (RE = La, Pr, Nd, Sm, Gd and Dy) in crystal and mechanical behaviours of sol-gel derived ZrO2-2 mol% REO2O3 spun fibres calcined at 1300°C

Crystal behaviours such as crystallization temperature (amorphous to tetragonal (t) zirconia), tendency of phase transformation (tetragonal to monoclinic (m) zirconia) and lattice strain were studied with mechanical property e.g. tensile strength of sol-gel derived ZrO₂-2 mol% RE₂O₃ (RE = La, Pr, Nd, Sm, Gd and Dy) spun fibres. Rare earth cations of varying sizes played a significant role in changing the above mentioned properties of ZrO₂-2 mol% RE₂O₃ fibres. It was found that with decreasing the ionic size difference between the zirconium and RE ions, crystallization temperature (amorphous →)t-ZrO₂) decreased, the probability of phase transformation (t→m) decreased, lattice strain which is related to lattice distortion decreased and tensile strength increased.     

Effect of Shear on the Rheology and Crystallization of Palm Oil

ABSTRACT:  This article reports on the impact of shear on crystallization upon cooling of palm oil. Samples were cooled down under shear from 70 to 10 °C, then kept at this temperature, while performing rheological measurements using a controlled shear rate rheometer and rheo-optical observations using optical microscopy and small-angle light scattering. Shear rates between 1 and 300 s⁻¹ were investigated. Two crystallization steps were observed, characterized by associated viscosity increases. The effect of shear on these 2 crystallization processes was investigated. Shear was shown to influence almost all of the steps of the structuring process of the crystallizing palm oil. The spherulite size and growth rate during the 1st crystallization are affected by shear. The onset time of the 2nd crystallization process strongly depends on the extent of shear. The steady state structures after the 1st and 2nd crystallization processes constituted of a suspension of aggregates of spherulites are controlled by the applied shear rate.
Practical Application: The texture of crystallized vegetal fats and subsequent end product properties depend on the structure developed during the crystallization process. This structuring process is strongly influenced by the thermo-mechanical history applied to the product (cooling rate, degree of undercooling, annealing time, application of flow). This article shows how the shear rate as well as extent of shear affects the different steps of the crystallization and aggregation processes in the case of palm oil after the 1st crystallization.     

Concomitant use of liquid–liquid batch and continuous plug flow reactors for kinetic model discrimination. Application to the Rh/TPPTS catalysed reduction of the C–C double bond in dimethylitaconate

The biphasic catalytic reduction of the C–C double bond of dimethylitaconate with a water soluble rhodium/triphenylphosphinetrisulphonated sodium salt (TPPTS) complex is investigated. Kinetic studies in a well-mixed batch reactor provide kinetics parameters and an activation energy of 71 kJ mol⁻¹ but cannot discriminate between a first order or a complex kinetic model within the range of substrate concentration where the approximation of linear liquid/liquid partition is respected. Catalytic tests in the centrifugal partition chromatograph (CPC) reactor under steady-state operations in chemical regime and plug flow mode allow discriminating the kinetic models, the complex kinetic rate law being preferred.     

The crystallization morphology and melting behavior of polymer crystals in nano-sized domains

The crystallization morphology and the melting behavior of the phase-separating poly(?-caprolactone) (PCL) and poly(ethylene oxide) (PEO) blends were studied using atomic force microscopy. Two blends consisting of PCL and PEO with weight ratios of 10/90 and 90/10 were prepared to form the isolated spherical domains by the phase-separating process. The results show that the melting temperatures of the PCL and PEO lamellae in the confined domains increased as the lamellar length increased, and the melting behavior of the PCL and PEO lamellae in the matrix and confined domains was also studied.     

Twisting orientation and the role of transient states in polymer crystallization

A possible connection is suggested and explored between non-planer crystal habits in banded polymer spherulites and disordered chain folding in polymers crystallized relatively rapidly from the melt. It is proposed that, when lateral growth faces and fold surfaces are not orthogonal (because chain stems are tilted with respect to the lamellar normal), different degrees of disorder develop at opposite fold surfaces. Resulting differences in surface stress give rise to bending moments, but these are likely to be of transient existence. It is shown that, on this basis, an appealingly simple rationale can be developed to account for the complex and hitherto puzzling observations of Bassett and Hodge on polyethylene spherulites, including S-bending and non-uniform axial twisting in lamellae, and also an empirical correlation between these deformations. Much depends, however, upon interactions between interleaved crystals and upon relaxation of bending moments. Existing evidence in support of the rationale is outlined. Implications with respect to polymers other than polyethylene, and to kinetics of crystallization in general, are discussed briefly. Calculations concerning axial twisting under the influence of surface stresses suggest that the twisted crystals incorporate twist boundaries, possibly formed by aggregation of dislocations generated during the growth of what must initially be relatively disordered crystals. The ‘chiral’ factor determining handedness of twisting in a given crystal is the direction in which chain stems tilt with respect to the lamellar normal.     

CFRPA1010等速降温结晶动力学的研究

将等温Ａｖｒａｍｉ方程推广应用于等速降温的非等温结晶过程，用ＤＳＣ法研究了ＣＦＲＰＡ１０１０的等速降温结晶行为和结晶动力学。结果表明，用此方法得到的动力学参数与文献报导的等温法结果有良好的一致性；ＣＦＲＰＡ１０１０中的ＣＦ使基体的结晶温度明显提高，使结晶峰呈不对称形态，结晶温度范围变窄。其结晶行为和动力学参数ｎ、ｋ、ｔ１／２等结果显示，ＣＦ具有诱导基体结晶作用，影响了ＰＡ１０１０结晶的成核和生长机