EFFECT OF VARIOUS ANTIOXIDANTS ON THE OXIDATIVE STABILITY OF ACID AND ALKALI SOLUBILIZED MUSCLE PROTEIN ISOLATES

Protein isolates prepared from cod ( Gadus morhua ) myofibrillar proteins using acid or alkali solubilization are susceptible to oxidative rancidity. Oxidation could be delayed by the exogenous addition of antioxidants. The objective of this research was to compare the efficacy of antioxidants such as δ-tocopherol, butylated hydroxyanisole (BHA) and propyl gallate, to inhibit oxidation in acid- and alkali- solubilized cod protein isolates. Oxidation was catalyzed using cod hemolysate. Oxidation of lipids was monitored by the measurement of thiobarbituric acid reactive substances and painty odor. Results showed that protein isolates prepared using the acid process was significantly ( P <  0.05) more susceptible to lipid oxidation than alkali-solubilized protein isolates. Regardless of pH treatments, the efficacy of various antioxidants decreased in the order propyl gallate  >  BHA  >  δ-tocopherol.

PRACTICAL APPLICATIONS

Research has shown that seafood available for human consumption is rapidly getting depleted and that many fish species may become extinct in the next half-century or so. Acid and alkali solubilization methods are recent but well-known techniques used for preparing protein isolates from under-utilized aquatic species and the by-products of seafood industry. Although numerous researchers have studied the use of acid and alkali processes on several sources of seafood, almost no research has been done on the use of antioxidants to protect protein isolates from lipid oxidation. In our research, we have studied the effect of various antioxidants on the oxidative stability of acid- and alkali-solubilized fish myofibrillar proteins. The results from this work will enable the seafood industry to properly identify the process and the type of antioxidants required for making muscle food products with increased oxidative stability.     

利用回归和人工神经网络预测城市雨水径流总磷模型的有效性

利用人工神经网络(ANN),探讨在不无监测系统的集水区城市降水质量预测的适用性.预测使用常规的气候和地理数据集,通过构建背景传播的神经网络和回归联合模型,克服利用逐步回归的方法对数据进行分析时违背独立数据假设的问题.研究通过交叉验证用于确定停止降水时间为输入变量参数,利用地区平均浓度(EMC)作为独立的变量,构建的模型比用负荷量构建的模型更精确.数据域和输入变量的选择对回归模型的准确性也有较大影响.但计算效率、动量和隐节点数目的选择等因素,对人工神经网络模型准确性的影响较小.同时,回归和人工神经网络模型的降水质量预测结果十分相似,但在不无监测系统的集水区域城市降水质量的预测方面,回归模型更有实效性.     

Resilience of super users’ mental models of enterprise-wide systems

Research on information system training has focused primarily on methods, while neglecting the effects of interruption intervals between training and system implementation. This empirical study examines the resilience of accurate mental models of an enterprise-wide system in a large health care facility. Accurate mental models were shown to withstand the passage of time and resulted in superior field performance following a crash conversion. Consistent with prior experimental research, certain types of learners were more likely to acquire these sounder mental models. In large organisations where the simultaneous training of users on a complex system is virtually impossible, scheduling is an important facet of the training paradigm. The main practical implications of this study involve the development of: (1) training programmes emphasising performance on far-transfer tasks, (2) training schedules designed to minimise knowledge erosion, and (3) criteria for selecting highly capable super users.     

Folly in Trade and Technology Policy (Comments on `Do we need atechnology policy?' by S.J. Kline and D.E. Kash)

The commenters note that S.J. Kline and D.E. Kash (ibid., vol.11, p.18-25, Summer 1992) raise a number of interesting points in their discussion of the functions of government technology policy. The commenters point out that the importance of the issues discussed by Kline and Kash is underscored by a recent tariff imposed on active-matrix liquid-crystal displays (AMLCDs). They suggest that it is important that the Kline and Kash article serve as the basis of continuing discussions within the IEEE community and other scientific and engineering communities, relative to issues of technology policy development. They conclude that perhaps the concerns expressed by Kline and Kash, and by N.W. Buckly (1992), will generate an increased level of understanding, concern, and discourse on this extremely important topic     

Studies on the influence of power ultrasound on dye penetration in leather dyeing using photomicrographic analysis

The use of power ultrasound in enhancing diffusion rate in various chemical as well as physical processes is gaining in importance. The influence of power ultrasound in the leather dyeing process on enhancing the penetration of dye through the leather matrix was studied. The penetration of dye through a leather cross-section for a given time in the presence and absence of an ultrasonic field (33 kHz, 150 W) was studied by photomicrographic analysis using a stereomicroscope. Different types of black dyes, such as Acid black 1, Metal complex black 194 and Direct black 155, were used for dyeing leather in the present study. Photomicrographic analysis of a cross-section of dyed leather indicated better penetration of dyes through the leather matrix with the use of ultrasound than without it. Therefore, the results indicate that ultrasound helps to improve the diffusion of dye and to reduce diffusional resistance in the leather dyeing process.     

利用厌氧生物反应器处理奶牛饲养废水

澳大利亚的畜禽养殖业,如奶牛饲养业,在不断的发展壮大,在生产中产生了大量的奶牛饲养废水,这些废水长期以来一直被视为主要的污染物扩散源.但是,常规的奶牛饲养废水处理方法,如两池系统,对该废水的处理并不充分.另外,从营养物质管理规划和固态粪便处理的角度讲,新的相关法规要求对该废水应采用新的处理和管理方法.厌氧消化（AD）是一种可替代技术,该技术不仅能使环境污染实现最小化,而且能够实现资源回收利用,尤其是可再生生物燃料（甲烷）产生,可实现资源利用的最大化.本研究以奶牛饲养废水为对象,在对AD技术进行简要综述的基础上,基于奶牛场废水管理实践和相关法规,对澳大利亚奶牛饲养场采用AD方法的必要性进行讨论.在澳大利亚,奶牛饲养场废水处理的独特之处在于采用了高效的厌氧消化池.本研究在实验过程中采用厌氧固定膜消化池来处理奶牛饲养场废水.初步结果表明,厌氧固定膜消化池能够将奶牛饲养场冲刷废水成功地转变为生物燃料气体.     

Enzymatic saccharification and fermentation of paper and pulp industry effluent for biohydrogen production

Paper and pulp industry effluent was enzymatically hydrolysed using crude cellulase enzyme (0.8–2.2FPU/ml) obtained from Trichoderma reesei and from the hydrolysate biohydrogen was produced using Enterobacter aerogenes. The influence of temperature and incubation time on enzyme production was studied. The optimum temperature for the growth of T. reesei was found to be around 29 °C. The enzyme activity of 2.5 FPU/ml was found to produce about 22 g/l of total sugars consisting mainly of glucose, xylose and arabinose. Relevant kinetic parameters with respect to sugars production were estimated using two fraction model. The enzymatic hydrolysate was used for the biohydrogen production using E. aerogenes. The growth data obtained for E. aerogenes were fitted well with Monod and Logistic equations. The maximum hydrogen yield of 2.03 mol H₂/mol sugar and specific hydrogen production rate of 225 mmol of H₂/g cell/h were obtained with an initial concentration of 22 g/l of total sugars. The colour and COD of effluent was also decreased significantly during the production of hydrogen. The results showed that the paper and pulp industry effluent can be used as a substrate for biohydrogen production.     

Structural integrity assessment of FBR components using a distributed computing environment

In this work, the structural integrity of the critical components of the fast breeder reactor (FBR) that are subjected thermal striping is assessed using a fracture mechanics approach based on linear elastic fracture mechanics (LEFM). The structural integrity is assessed in terms of the actual life of the component for a particular difference between the hot and cold liquid temperatures at the critical mixing velocities. A generalized procedure is attempted for the computation of fatigue life. It is demonstrated in this work that the analysis procedure adopted is computationally very efficient. Green's function method is used for transient mode I crack propagation analysis. An inherent parallelism in the method is exploited for computational efficiency. A distributed computing environment is, therefore, used to demonstrate the effectiveness of Green's function method for crack propagation analysis for the kind of problem solved in this work. A simple idealization in the form of flat plate geometry is used in a numerical example to show the computational efficiency. The method shows a good scale‐up justifying the benefit of using a distributed computing environment given a large amount of input data for the thermal striping problem.     

Tolerance design of mechanical assembly using NSGA II and finite element analysis

The technological and financial limitations in the manufacturing process are the reason for non-achievability of nominal dimension. Therefore, tolerance allocation is of significant importance for assembly. Conventional tolerance allocation methods are limited by an assumption that all parts are rigid. Every mechanical assembly consists of at least one or more flexible parts which undergo significant deformation due to inertia effect. Finite element analysis is used to determine the deformation of components in an assembly. Therefore, integration of statistical tolerance design with finite element analysis will guarantee that the optimal tolerance values of various components of the assembly obtained as end product of the tolerance design will remain within tolerance variation. Then the product can function as intended under a wide range of operating conditions for the duration of its life. In this paper, tolerance design of a piston cylinder assembly is done to demonstrate the proposed methodology.