煅烧设备对建筑石膏性能影响的探索研究

概述了国内建筑石膏的主要煅烧设备及其煅烧方式,重点研究了不同煅烧设备制备出的建筑石膏的物理和化学性能,从而分析比较不同煅烧设备对建筑石膏的影响。     

Preventing Wetting Between Liquid Copper and Solid Steel: A Simple Extraction Technique

Metallurgical and Materials Transactions B - Copper contamination of end-of-life steel scrap is the main barrier to high-quality recycling. Preferential melting of copper from solid steel scrap is...     

Impact of dietary fiber coatings on behavior of protein-stabilized lipid droplets under simulated gastrointestinal conditions

Multilayer emulsions containing lipid droplets coated by lactoferrin (LF) - anionic polysaccharide layers have improved resistance to environmental stresses (such as pH, salt, and temperature), but their behavior within the gastrointestinal tract (GIT) is currently unknown. The objective of this research was therefore to monitor changes in the physicochemical properties and digestibility of these systems under simulated GIT conditions. Primary emulsions (5% corn oil, 0.5% LF) were prepared using a high-pressure homogenizer. Secondary emulsions (5% corn oil, 0.5% LF, 0.5% polysaccharide) were prepared by incorporating alginate, low methoxyl pectin (LMP) or high methoxyl pectin (HMP) into primary emulsions. Emulsions were then subjected to simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) conditions in sequence. LF, LF-LMP and LF-HMP emulsions were stable to droplet aggregation in the stomach but aggregated in the small intestine, whereas LF-alginate emulsions aggregated in both the stomach and small intestine. The presence of a dietary fiber coating around the initial lipid droplets had little influence on the total extent of lipid digestion in SIF, but LF-alginate emulsions had a slower initial digestion rate than the other emulsions. These results suggest that the dietary fiber coatings may become detached in the small intestine, or that they were permeable to digestive enzymes. Pepsin was found to have little influence on the physical stability or digestibility of the emulsions. The knowledge obtained from this study is important for the design of delivery systems for encapsulation and release of lipophilic bioactive ingredients.     

Modulation of physicochemical properties of emulsified lipids by chitosan addition

Electrostatic interactions between polysaccharides and proteins at oil–water interfaces alter the physicochemical properties and stability of emulsions. In this research, we studied the influence of chitosan addition on the properties of oil-in-water emulsions containing whey protein-coated lipid droplets. Experiments were carried out under conditions where the protein and polysaccharide had similar charges (pH 3.0) or opposite charges (pH 6.5). At pH 3.0, chitosan addition (0–0.025%) had little influence on droplet charge, aggregation, creaming stability or shear viscosity of whey protein emulsions, which was attributed to the fact that the cationic chitosan molecules did not adsorb to the cationic droplet surfaces due to electrostatic repulsion. At pH 6.5, chitosan addition caused a decrease in particle negative charge, an increase in particle size, a decrease in creaming stability, and an increase in viscosity. These effects were attributed to droplet aggregation caused by charge neutralization and bridging resulting from attraction of cationic chitosan molecules to anionic patches on the protein-coated droplet surfaces. Addition of cationic polyelectrolytes to protein-stabilized emulsions may be utilized to control their physicochemical properties, stability and biological fate, which may be useful for developing commercial products with novel or improved functional properties.     

Analysing utility tunnels and highway networks coordination dilemma

Utilities are an integral component of the total transportation network comprising highways, railways, airways, and waterways, as well as pipelines, wires, and cables that transport people, goods, and public services. The perennial dilemma of mutual interference between utility lines and transportation networks could be minimised making use of utility tunnel systems. Utilidors most striking feature is that they house several types of power, water, sewage, communications, gas and other statutory services in an easily accessible space. Placing utilities in tunnels under public rights-of-way reduces the continual cutting of pavements resulting from utility burial practices and facilitates the installation, inspection, replacement, and maintenance operations. Utility tunnels and transportation networks may not be compatible at transmission levels. Highway systems are generally planned to avoid high-density areas insofar as is possible. However, where the location of utility networks coincides sufficiently with the highway routes, the situation becomes more favourable to the utility tunnel concept. This paper discusses how compatibility of utility system networks with highway system networks could be greatly improved by appropriate attention to utilidor systems in urban planning. A sustainable approach to the dilemma of where to locate utilities in urban streets and highways has become urgent as the need for services expands in our modern cities. Interference between the safety and flow of highway traffic and utility tunnel operation could be a problem unless adequate measures are undertaken.