Water reuse in a shrimp processing line: Safety considerations using a HACCP approach

The large consumption of water involved in food manufacturing is prompting food processors to optimise the use. Treating and reusing or recycling water within the food plant results in substantial reduction of water use and wastewater production and discharge. If implemented, water reuse should be integrated into existing HACCP programs, and HACCP plans specifically addressed to the actual reuse should be elaborated. This paper evaluates the microbiological safety issues associated with water recycling during the production of shrimps (Pandalus borealis) in brine, and it indicates how the hazards may be effectively controlled using a HACCP approach. Following these procedures, process water recovered from peeling during shrimp processing and treated by means of reverse osmosis could be recycled within the same food unit operation.     

Stress function with finite magnitude of stress concentration around an interface crack

A new mathematical model for study of an interface crack between two dissimilar elastic half planes is proposed. A process zone is formed along the interface between the physical crack and the continuous part. Both the crack opening (and sliding) displacement with a smooth shape and the finite magnitude of stress concentration appear in this zone. The analytical model is expressed by closed elastic solutions using complex variables, but with no oscillations at the crack tip.     

由土壤水分特征曲线反推土壤孔隙分形维数

利用分形几何理论，可在水分特征曲线与土壤结构分维之间建立一定的函数关系式。利用这些函数关系式与Campbell经验公式具有相同或相似的幂定律形式的特点，由土壤水分特征曲线反推土壤孔隙分形维数，这不仅可以揭示Campbell经验公式与土壤孔隙结构之间的内在联系，还可为建立土壤非饱和水力参数的分形模型提供理论依据。     

棒线材无头轧制系统主要工艺过程分析

无头轧制技术是近几年在轧钢行业得以成功应用的一种新的轧制工艺,介绍了棒线材无头轧制系统的组成,并对其主要工艺过程进行了分析.     

正丁基硫醇-正辛烷体系等压气液相平衡研究

利用双循环气液平衡釜测定了101.3 kPa下正丁基硫醇-正辛烷体系的气液平衡数据,并运用该实验结果,进一步获得组分的液相活度系数。实验数据经Herrington方法检验符合热力学一致性。用UNIQUAC热力学模型对该实验数据进行处理,计算结果与实验值的平均绝对偏差为0.050 5。     

Characterization of the ceramic–metal brazed interface using ultrasonic technique

Sintered Al₂O₃ is brazed with 304 stainless steel (SS) using 97(Ag28Cu)3Ti active filler alloy at 1000 °C. Electron Probe Micro Analysis (EPMA) studies of the interfaces are carried out. The thickness of the interfaces are measured from the concentration penetration profile. Shear strength of the joint is evaluated. The qualities of the joints are characterized using ultrasonic technique. Mechanical properties of the joints are correlated with the obtained ultrasonic signals during the ultrasonic scanning of the sample.     

Fabrication and characterization of TiO2/short MWNTs with enhanced photocatalytic activity

TiO₂/short MWNTs nanocomposites were prepared by the sol–gel method using butyl titanate and short MWNTs as starting materials in the solvent of isopropyl alcohol. Their photocatalytic activity in the degradation of X-3B was studied. The effects of mass ratio of short MWNTs to butyl titanate, and heat-treatment temperature on the photoactivity of TiO₂/short MWNTs nanocomposites were discussed. For comparison purpose, other photocatalysts were also employed in the photodegradation experiment. Thermogravimetric–differential thermal analysis (TG–DTA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV–Vis absorption spectra were utilized to characterize the prepared photocatalysts. The results showed that the TiO₂/short MWNTs nanocomposites synthesized with 1% mass ratio of short MWNTs to butyl titanate had the best photoactivity.     

Exact integration in the boundary element method for two-dimensional elastostatic problems

This paper derives the exact integrations for the integrals in the boundary element analysis of two-dimensional elastostatics. For facilitation, the derivation is based on the simple forms of the fundamental functions by taking constant, discontinuous linear and discontinuous quadratic elements as examples. The efficiency and accuracy of the derived exact integrations are verified against five benchmark problems; the results indicate that the derived exact integrations significantly reduces the CPU time for forming the matrices of the boundary element analysis and solving the internal displacements.     

Effect of charge trapping species of cupric ions on the photocatalytic oxidation of resorcinol

The photocatalytic oxidation of resorcinol, a potent endocrine disrupting chemical, in oxygenated aqueous suspensions of pure and cupric ions modified Degussa P25 titanium dioxide has been investigated at pH 3.0 ± 0.5. The initial rate of photocatalytic oxidation of resorcinol increased until an optimum dissolved cupric ions concentration was reached at 1.04 mM. At the optimum concentration of cupric ions, the initial rate of photocatalytic mineralisation and degradation of resorcinol was improved by 400%. The observed beneficial effect of cupric ions on the initial rate of resorcinol oxidation could be attributed to the formation of complex and its participation in the photoredox cyclic reaction.Two of the initial oxidation intermediates detected were 1,2,3-trihydroxybenzene and 1,2,4-trihydroxybenzene. These intermediates were formed via hydroxylation of the aromatic ring of resorcinol. Evidences have revealed that 1,2,4-trihydroxybenzene interacted strongly with cupric ions forming copper(II)-trihydroxybenzoate complexes that possessed good adsorption onto TiO₂ surface. These dual-effects help to draw the metal ions closer to the photocatalyst surface and subsequently trigger the electron trapping mechanism by cupric ions. As a result, this improved the charge carriers’ separation. Furthermore, in the presence of oxygen, reoxidation of photoreduced cupric ions occurred and this eliminated the possibility of copper photodeposition, while inducing a photoredox cyclic reaction to regenerate copper species that may potentially act as co-catalyst for the oxidation of 1,2,4-trihydroxybenzene. In contrast, no obvious complex formation was seen between 1,2,3-trihydroxybenzene and cupric ions. This pointed to an intriguing finding which indicates that the positioning of functional group on benzene ring influences the role of cupric ions.