助磨剂组分与水泥超塑化剂适应性的初步探讨

本文选择常用助磨剂主要组分,分别在粉磨过程中掺入及在水泥成品中外掺两种方式下初步探讨了掺助磨剂的水泥与超塑化剂适应性。实验结果表明,在粉磨过程中掺入本试验选用的五种助磨剂组分制成的水泥与超塑化剂均存在适应性不良的现象;而在水泥成品中外掺配制的助磨剂则无此现象。通过其它辅助实验及相关文献,初步探讨了助磨剂组分与水泥超塑化剂适应性的主要影响因素。

Evaluating the Effectiveness of Air Pollution Abatement Policy of Hong Kong

As only about 15% of the total time of people in Hong Kong was spent outdoors, it would be more valuable if the associated effectiveness and impact of the recently proposed abatement measures could be expressed in terms of the improvement in the total exposure levels. This paper uses an exposure assessment model developed from the local microenvironment concentration data together with our surveyed time activity patterns to evaluate the effectiveness of the proposed air pollution abatement policy. Prior to the enforcement of abatement measures, about 2.5% of the young group and 1.2% of the adult group having their exposure levels exceeded that defined by the current 8-hour PM10 standard (180 μg/m3). With the enforcement of abatement measures, only 0.3% of the adult group would be restored to a safe level.

Prediction of mass transfer coefficients in an asymmetric rotating disk contactor using effective diffusivity

Mass transfer characteristics have been investigated in a 113 mm diameter asymmetric rotating disk contactor of the pilot plant scale for two different liquid–liquid systems. The effects of operating parameters including rotor speed and continuous and dispersed phase velocities on the volumetric overall mass transfer coefficients are investigated. The results show that the mass transfer performance is strongly dependent on agitation rate and interfacial tension, but only slightly dependent on phase flow rates. In this study, effective diffusivity is used instead of molecular diffusivity in the Grober equation for estimation of dispersed phase overall mass transfer coefficient.The enhancement factor is determined experimentally and there from an empirical expression is derived for prediction of the enhancement factor as a function of Reynolds number. The predicted results compared to the experimental data show that the proposed correlation can efficiently predict the overall mass transfer coefficients in asymmetric rotating disk contactors.

Relative Effectiveness of Ultraviolet Light Irradiation and Chlorination against Indigenous Bacteriophage and Bacteria in Primary Treated Wastewater

The effectiveness of chlorine and ultraviolet light at inactivating indigenous microbes in primary treated wastewater was examined in this study. The inactivation rates for somatic colipahge and F-specific bacteriophage were less than 2.5 log and 1 log, respectively, at either free chlorine doses of 6, 15 mg/L and 30 mg/L after 30 minutes contact time. However, E. coli and total coliforms were susceptible to chlorination and inactivated more than 4 log within first 15 minutes of contact time at any chlorine dosage tested. In contrast, the inactivation of bacteriophage was increased when increasing UV fluence. At the same disinfection effectiveness against E. coli, UV disinfection was more effective than chlorination against F-specific bacteriophages.

The Knee Wear Prediction of UHMWPE Tibial Insert Using VIPRO Platform

The failure mechanism was postulated as a combination of the high level of loading during normal activities and a non-conforming contact mechanism between the femoral condyles and the tibial insert. The question that arises is： could be this phenomenon evaluated quantitatively a priori, e.g., could be the failure due to delamination wear predicted？ In order to do some finite element simulations were performed to dynamically determinate the contact area and contact pressure for three different activities. The results obtained using VIPRO platform lead to the conclusion that many clinically reported failures of the tibial tray are caused by the adhesive and fatigue wear.

Highly efficient organic solar cells enabled by a porous ZnO/PEIE electron transport layer with enhanced light trapping

In this study,a porous inorganic/organic(ZnO/PEIE,where PEIE is polyethylenimine ethoxylated)(P-ZnO)hybrid material has been developed and adopted in the inverted organic solar cells(OSCs).The P-ZnO serving as the electron transport layer(ETL)not only presents an ameliorative work function,but also forms the cratered surface with increased ohmic contact area,revealing suppressed charge recombination and enhanced charge extraction in devices.Particularly,P-ZnO-based OSCs show improved light trapping in the active layer compared with ZnO-based ones.The universality of P-ZnO serving as ETL for efficient OSCs is verified on three photovoltaic systems of PBDB-T/DTPPSe-2 F,PM6/Y6,and PTB7-Th/PC_(71)BM.The enhancements of 8%in power conversion efficiency(PCE)can be achieved in the state-of-the-art OSCs based on PBDB-T/DTPPSe-2F,PM6/Y6,and PTB7-Th/PC_(71)BM,delivering PCEs of 14.78%,16.57%,and 9.85%,respectively.Furthermore,a promising PCE of14.13%under air-processed condition can be achieved for PZnO/PBDB-T/DTPPSe-2F-based OSC,which is among the highest efficiencies reported for air-processed OSCs in the literature.And the P-ZnO/PBDB-T/DTPPSe-2F-based device also presents superior long-term storage stability whether in nitrogen or ambient air-condition without encapsulation,which can maintain over 85%of its initial efficiency.Our results demonstrate the great potential of the porous hybrid PZnO as ETL for constructing high-performance and air-stable OSCs.