纸浆漂白成本在线计算模型构建及应用研究

能源和化学品价格的快速上涨使得制浆工作者尤为关注如何降低纸浆漂白成本。本研究构建了纸浆漂白成本的在线计算模型,并应用于典型ECF漂白技术(D0EpPD1),同时系统分析了影响纸浆漂白成本的主要因素和该模型在漂白工艺条件优化过程中的应用效果。研究发现,化学品成本是影响漂白成本的最主要因素,其次是能源成本、废水处理成本、清水成本;化学品中ClO2用量对纸浆漂白成本的影响最大,其次是H2O2用量,NaOH用量影响最小;能源成本中蒸汽用量对纸浆漂白成本影响最大;而清水成本和废水处理成本影响最小;通过对化学品用量、漂白温度等漂白工艺条件的调整可降低纸浆漂白成本;该模型可实现对漂白工艺条件的优化或能源及化学品价格变化后纸浆漂白成本的在线预测,也是实现纸浆漂白系统全局优化、进一步降低漂白成本的基础。     

The effect of pH,salts and sugars on the rheological properties of cress seed (Lepidium sativum) gum

Effect of shear rate (15–600 s^?1), gum concentration (1–2%), pH (3–9), sucrose (10–40%), lactose (5–15%), NaCl (100–300 mm ) and CaCl₂ (5–50 mm ) was evaluated on apparent viscosity (η_a), flow behaviour index (n), consistency coefficient (K) and yield stress (τ₀) indices of cress seed gum (CSG) solutions. Different rheological models were used to fit the experimental data, although the Herschel–Bulkley model was found the best model. An increase in gum concentration led to an increase in τ₀, η_a, and k and a decrease in n values. The addition of salts lowered the k value; however, the n value showed slight significant change. The presence of sugar resulted in the enhancement of n, k, τ₀ and η_ap values. The existence of yield stress and pseudoplastic behaviour of CSG, its stability against salts, wide range of pH and synergic effect of sugar make it a good thickener and stabiliser in food formulations.     

Factorial optimisation of the effects of extrusion temperature profile and polymer grade on as-spun aliphatic–aromatic co-polyester fibres III: mechanical properties

The effect of extrusion temperature profile in the melt‐spinning process of as‐spun linear aliphatic–aromatic co‐polyester (AAC) fibres upon their mechanical properties and process productivity was modelled by using factorial experimental designs. After the viscoelastic and morphology characteristics of the polymer were considered using Differential Scanning Calorimetry and Melt Flow Index (MFI), the rheological data were used to determine the enhanced melt‐spinning temperature of the six heating zones in the process. Tensile strength, elongation at break, modulus and fibre productivity (g/min) of the melt‐spinning process have been quantitatively assessed as responses to polymer grades and extrusion zone temperature. The optimisation of mechanical properties and productivity helps in understanding and controlling the most desired properties in the produced fibre. It has been noted that the die head temperature (spinning temperature), the polymer grade and their interaction are the most significant factors affecting the mechanical properties. Analysis of the fibre productivity shows that the polymer grade and its interaction with the die head temperature is significant in terms of influencing the output of the melt‐spinning process, which could be related to the polymer molecular weight and polymer structure. There is an interaction between polymer grade and feeding zone temperature which is related to the material supply action in the feeding zone. The friction between the screw and the material is affected by heating action, which affects the moisture content and the molten material rheology. By adjusting the extrusion temperature profile and selecting the more applicable spin‐able polymer grade through a statistical forecasting model, the combination of the cost related to material grade and processing cost controls the fibre production cost. The fibre made of low MFI grade has better structure and mechanical properties than that made of the higher MFI grade, and the former will be preferred for future work. With previous work related to the effects of extrusion temperature profile on the fibre structure, the present paper will help in developing the production process of biodegradable linear AAC fibres.     

Impact properties of thermoplastic composites

The excellent properties exhibited by thermoplastic composites at much reduced weight have attracted attention in the development of products in different sectors. Thermoplastic (TP) composites, because of their distinctive properties as well as ease of manufacturing, have emerged as a competitor against the conventional thermoset resin-based composites. Depending on the application, these composites may undergo impact events at various velocities and often fail in many complex modes. Hence, the development of TP composites having high energy-dissipation at (the desired) much-reduced weight has become a challenging task, but it is a problem which may be alleviated through the appropriate selection of materials and fabrication processes. Furthermore, fibre surface modification has been shown to increase fibre-matrix interfacial adhesion, which can lead to improved impact resistance. Textile preforms are helpful in acting as a structural backbone in the composites since they offer a relatively free hand to the composite designer to tailor its properties to suit a specific application. Additionally, hybrid textile composite structures may help in achieving the desired properties at much lower weight.

Simulation software can play a significant role in the evaluation of composites without damaging physical samples. Once the simulation result has been validated with actual experimental results, it should be possible to predict the test outcomes for different composites, with different characteristics, at different energy levels without conducting further physical tests. Various numerical models have been developed which have to be incorporated into these software tools for better prediction of the result.

In the current issue of Textile Progress, the effects of various materials and test parameters on impact behaviour are critically analyzed. The effect of incorporating high-performance fibres and natural fibres or their hybrid combination on the impact properties of TP composites are also discussed and the essential properties of TP polymers are briefly explained. The effects of fibre and matrix hybridization, environmental factors, various textile preform structures and fibre surface modification treatments on the impact properties of thermoplastic composites are examined in detail. Various numerical models used for impact analysis are discussed and the potential applications of TP composites in automobile, aerospace and medical sectors are highlighted.     

纺织数码喷墨印花发展趋势

阐述了印染工艺的含义及分类,介绍了传统丝网印花原理以及优缺点,分析了传统丝网印花与数码喷墨印花的本质区别。详细介绍了数码喷墨印花在加工、交货周期、印花效果以及环保节能方面的优势,阐述纺织数码印花产业集中区域,预估全球数码印花量增长趋势。     

Cadmium accumulation in Agaricusblazei Murrill

BACKGROUND: Agaricus blazei Murrill has become a popular food source of high nutritional and medicinal value in many Asian countries. However, there are growing health concerns on cadmium (Cd) accumulation by A. blazei. Experiments were conducted to investigate Cd accumulation patterns in A. blazei and to identify key factors contributing to Cd accumulation. RESULTS: Cd concentrations in the substrates and subsequent fruit bodies declined rapidly after the first, second and third harvest wave. A quick rinse of the fruit bodies in water reduced the Cd concentration by 27–54% depending on the strain. The Cd concentration in the fruit bodies decreased as the fruit body yield m^?2 or fruit body number m^?2 increased, while it increased as the substrate Cd content or fruit body size increased. Cd accumulation was positively associated with phosphorus (P) uptake. CONCLUSION: The results suggests that, in the A. blazei‐growing region studied, Cd and P concentrations in the substrates and casing soil should be reduced in order to effectively minimise Cd accumulation in the fruit bodies. It is also necessary to improve fruit body yield by increasing the number of medium‐sized fruit bodies. Overgrowth of individual fruit bodies stimulates Cd accumulation in A. blazei. Copyright © 2008 Society of Chemical Industry     

联机事务处理技术及模型概要设计

简要介绍了计算机联机事务处理的技术原理，详细阐述了一个实际的联机事务处理系统证券交易所主机系统中的系统进程及应用进程，以说明联机事务处理平台的模型设计及具体实现。     

Modelling of the hydrolysis of sorghum straw at atmospheric pressure

Sorghum straw is a renewable, cheap and widespread resource. The acid hydrolysis of sorghum straw to obtain xylose solutions could be a good alternative for this abundant resource. The H₂SO₄ hydrolysis of sorghum straw at two different temperatures (80 and 100 °C) and three H₂SO₄ concentrations (2, 4 and 6%) using a solid/liquid ratio of 1:10 (w/w) was studied. Kinetic parameters of mathematical models for predicting the concentrations of xylose, glucose, acetic acid and furfural were determined. The activation energy of the release reaction was 183.3 kJ mol^?1 for xylose and 185.8 kJ mol^?1 for glucose. The optimal conditions found were 6% H₂SO₄ at 100 °C for 60 min, which allow one to obtain a solution with 18.27 g xylose l^?1, 6.78 g glucose l^?1, 0.7 g furfural l^?1 and 1.35 g acetic acid l^?1. It is concluded that this process has potential for utilisation of this renewable lignocellulosic resource. © 2002 Society of Chemical Industry     

关于低温肉制品发展趋势的一点思考

简要分析了低温肉制品的现状及存在的主要问题，提出了低温肉制品产业结构和食品安全等方面的发展趋势。     

我国人造板机械发展现状及走势分析

简要介绍了我国人造板机械的发展过程,分析了国内人造板机械存在的问题和发展趋势.