Sorption of solvents in plastics and solvent desorption and retention

The experiments reported here have studied the following systems within the temperature range 25–50°C: sorption and desorption of solvents on LDPE, OPP, PS, rigid PVC, OPA, PETP and regenerated cellulose with methanol, ethanol, n-propanol, and ethyl acetate. With reference to these, the theory presented indicates the most important aspects related to the tests, refers to identification data on similar problems and enumerates the possibilities of interaction. The application of equation 1 and the reported measuring method allows the determination of diffusion coefficients within a vapour-saturated atmosphere system. As the gravimetric method also allows the determination of solubilities (α_L, the solubility coefficient), the permeation behaviour in the Fick range is calculable from The equation used by the author can be related to other equations from the technical literature, such as for the range Q_(t)Q∞>0.4, or where for the range <0.4 The agreement can be considered as good. The D values provide a calculation base within the scope of the outlined problem definition. The taste limits for solvents in water reveal which solvents could, as residual solvents, become critical. These values—connected with sorption/desorption identification values, evaporation numbers etc. —indicate where there is a risk and those cases where sufficient drying, or even the use of more adequate solvents is essential.     

一种制做三维牙——颌骨光弹性模型的新方法

本文提出一种用“整体浇注法”制做三维牙——颌骨光弹性模型的新方法,即用价格便宜的石膏做阴模,先制出与真实牙几何相似的牙光弹性模型和模拟牙周膜的乳胶套,将它们粘接好,然后将其放入颌骨石膏阴模的适当位置,浇入环氧树脂混合液,用“二次固化法”进行固化,即可制成三维牙——颌骨整体光弹性模型。此法能保证模型与实物的严格几何相似和牙周的边界条件相似,使实验精度大大提高且工艺简单、成本低。     

石英砂的相变与换向器套筒铸件的变形

用呋喃树脂石英砂工艺生产牵引电机换向器套筒出现变形、裂纹等铸造缺陷,是由石英砂相变膨胀引起,后用高铬刚玉砂代替石英砂得到解决.     

辊底式退火炉的炉体改造

分析了辊底式退火炉存在的问题，提出改进措施及改造后节能效果。     

Determination of heavy metals and volatile aromatic compounds in used engine oils and sludges

Assessment of contaminant releases during utilization of used oils is essential for the determination of environmental acceptability. These paper reports the results of the study examining a toxic metal leachability from used engine oil and sludge samples employing leaching test (TCLP). The leaching test indicated that lead in oil samples exceeded 5-ppm concentration level what qualified them as a toxic waste. The samples of contaminated sludge were found to contain high concentration of total lead, barium and chromium, but the leaching test showed concentration below regulatory limit. The total content of benzene, ethylbenzene, toluene, and xylenes (BETX), and naphthalene in used oil and sludge samples was also determined and was found not to be a significant factor to contamination.     

纺牵—步法中粗旦丙纶长丝沸水收缩率初探

在纺牵联合一步法纺丝机上研究了丙纶切片的熔融指数对纤维沸水收缩率的影响，发现熔融指数高的切片，其纤维的沸水收缩率变化大。沸水收缩率随热定型的温度升高而下降。沸水收缩率可根据用户提供中心值（Ｍ）通过实验确定，一般以Ｍ±１．５为宜。     

Thermodynamic Criteria for the Maximum and Minimum Strength of Fibre-Reinforced Composite Materials

The overall performance and reliability of composite materials are, in most cases, dependent upon the behaviour of the reinforcement-matrix interface, particularly upon its ability to transfer stress.

A theory for predicting thermodynamic conditions for the maximum and zero-adhesion at the reinforcement-matrix interface is tested in this paper, based on experimental data. Proposed is a model of the relationship between mechanical properties of composite materials (tensile strength, flexural strength, Young's modulus and impact resistance) and energetic properties of matrix and reinforcement expressed by the energy ratio a = γ_l/γ₂.     

Influence of the composition of the binder and the carbonation on the zeta potential values of hardened cementitious materials

Electroosmotic experiments have been carried out on eight different mixes of hardened cementitious matrixes including concrete, mortar and pastes, different types of binders, carbonated and non-carbonated specimens and different test conditions. From these trials, the zeta potential values have been determined and the optimum experimental parameters and devices have been established. In addition, the influence of the composition of the binder on the zeta potential has been quantified indicating that higher amounts of Al₂O₃ in the binder lead to higher positive values of zeta potential, while the SiO₂ acts just on the opposite side. This has been explained in terms of the different i.e.p. (isoelectric point) for both oxides. Concerning the influence of carbonation, it increases the absolute value of the zeta potential toward more negative values; this behaviour has been attributed to the influence of the specifically adsorbed Ca²⁺ in the negative sites of the surface in the non-carbonated samples.     

用预分解技术改造Φ4×60m预热器窑的又一成功实例

介绍南京水泥工业设计研究院用预分解生产技术对山东水泥厂Φ4×60m预热器窑烧成系统进行的成功技术改造。技改设计指标为：熟料产量保证指标1500t／d，争取指标1700t／d，熟料热耗＜3762kJ／kg，熟料28d抗压强度＞60MPa。整个工程停产施工耗时仅用48d，烧成系统技改共耗资约3000万元。技改后一次点火投料成功，且点火当月即实现72h达标考核，所有设计指标均达标。     

Proposal of a uniform color scale for virgin olive oils

A new color scale was developed from a broad data set of 1700 virgin olive oil samples over four crop seasons, which can be considered highly representative of the whole color range of virgin olive oils available in Spain. This color scale provides a new set of 60 color standards, improving the results achieved by the old 60-color standards proposed by the bromthymol blue method. Seeking the greatest possibility of including a near match between colors of virgin olive oils and proposed standards, we developed our new color scale using a recent uniform color space, with standards placed in a regular rhombohedral lattice like the one employed by the Uniform Color Scales of the Optical Society of America. The average color difference between each of the 1700 virgin olive oils and its nearest standard is reduced from 8.17 CIELAB units, using the bromthymol blue standards, to 3.99 CIELAB units using the new standards. Within a color tolerance of 7.0 CIELAB units, 93.2% of our virgin olive oils can be classified with the new standards, but only 59.1% with the bromthymol blue ones. In the interest of future adoption, the performance of the new color standards should be tested by industry and researchers.