Effect of Clean Air Core Geometry on Fine Particle Contamination And Calibration of a Virtual Impactor

ABSTRACT

The optimum diameter and position of the clean air core in a clean air core virtual impactor were experimentally determined. It was found that the clean air core diameter should be at least twice as large as the converging nozzle diameter and that the clean air core should be positioned so that the ratio of the clean air flow velocity to the aerosol flow velocity ranges from 1.5 to 5.0 at the outlet of the clean air tube. Use of a laminator in a virtual impactor was found to increase the particle loss while maintaining almost the same collection efficiency curve.     

Effect of Fiber Length on Carbon Nanotube-Induced Fibrogenesis

Given their extremely small size and light weight, carbon nanotubes (CNTs) can be readily inhaled by human lungs resulting in increased rates of pulmonary disorders, particularly fibrosis. Although the fibrogenic potential of CNTs is well established, there is a lack of consensus regarding the contribution of physicochemical attributes of CNTs on the underlying fibrotic outcome. We designed an experimentally validated in vitro fibroblast culture model aimed at investigating the effect of fiber length on single-walled CNT (SWCNT)-induced pulmonary fibrosis. The fibrogenic response to short and long SWCNTs was assessed via oxidative stress generation, collagen expression and transforming growth factor-beta (TGF-β) production as potential fibrosis biomarkers. Long SWCNTs were significantly more potent than short SWCNTs in terms of reactive oxygen species (ROS) response, collagen production and TGF-β release. Furthermore, our finding on the length-dependent in vitro fibrogenic response was validated by the in vivo lung fibrosis outcome, thus supporting the predictive value of the in vitro model. Our results also demonstrated the key role of ROS in SWCNT-induced collagen expression and TGF-β activation, indicating the potential mechanisms of length-dependent SWCNT-induced fibrosis. Together, our study provides new evidence for the role of fiber length in SWCNT-induced lung fibrosis and offers a rapid cell-based assay for fibrogenicity testing of nanomaterials with the ability to predict pulmonary fibrogenic response in vivo.     

Effect of the Interfacial Transition Zone on the Conductivity of Portland Cement Mortars

The electrical conductivity of portland cement mortars was determined experimentally as a function of the volume fraction of sand and the degree of hydration. The results were analyzed using theoretical models that represent the mortars as three-phase, interactive composites. The three phases are the matrix paste, the aggregate, and the thin interfacial transition zone between the two. The microstructure and properties of the conductive phases (the transition zone and the matrix paste) were determined by a micrometer-scale microstructural model, and were used in conjunction with random-walk algorithms and differential-effective medium theory to determine the overall mortar conductivities. The presence of the transition zone was not found to significantly affect the global electrical conductivity of the mortar. However, there were significant differences in conductivity between the transition zone and matrix pastes when examined on a local level. These differences were found to vary with hydration and were most significant when the degree of hydration was between 0.5 and 0.8.     

The effect of nucleating agents on glycerol monostearate antistat performance in three polypropylene resins

The effect of polypropylene nucleation on glycerol ester antistat performance is studied by measuring the electrostatic decay times of injection molded specimens. Behaviors in homopolymer, random copolymer, and block copolymer are compared. Antistat performance is related to crystallinity using DSC.     

Experimental evaluation of a multivariable adaptive nonlinear predictive controller

A new multivariable adaptive nonlinear predictive controller is designed using a general nonlinear input-output model and variable transformations. The controller is similar in form to typical linear predictive controllers can be tuned analogously or by specifying a single parameters for each controlled variable. In addition, the design procedure is computationally efficient. The new controller is compared to a multi-loop proportional-integral (PI) controller with one-way static decoupling and to an adaptive linear predictive controller through tests on a simulated nonlinear distillation column. The new controller performed well in an experimental application to a multicomponent distillation column.     

Automated High Throughput Screening of Fluorescent Imaging Plate Reader (FLIPR) Assays Using Assay Platform™ Integrated with Activity Base for ‘on the fly’ Compound Reconfirmation

Advances in the field of automation have meant hitherto complex manual cell-based assays can now be automated. These improvements have brought significant enhancements in throughput, data fidelity and consistency, and allowed a reallocation of constrained resources.Building upon these improvements, we have linked our automated cell-based screening system, Assay Platform™, to Activity Base (IDBS), a software package designed to automate the analysis of HTS data. Customisation of this package has resulted in software that can identify ‘active’ compounds and re-pick them ‘on the fly’ from the original compound plates for triplicate re-testing without operator intervention.Based on an operator initially defining ‘normal’ parameters for assay activity in Activity Base, combined with an automated quality control software module that checks data fidelity, wells containing ‘active’ compounds can be re-picked and re-tested at the end of an automated screening run. Automating cell-based assays has significantly improved productivity, and, with the synergism of Activity Base, has given us greater power to complete each screening run and report ‘active’ compounds to Chemistry more rapidly. This article presents our approach to the automation of cell-based Fluorescent Imaging Plate Reader (FLIPR) screening together with automated active re-test confirmation using Activity Base.     

Solar energy in photosynthesis

Solar energy provides the reducing power within green leaves to convert CO₂ and H₂O into sugars. The CO₂ is supplied by the atmosphere and enters the leaf by diffusion. Factors affecting the rate of photosynthesis must either change the CO₂ diffusive resistances or the CO₂ concentration gradient along the diffusion pathways. Therefore, these effects can be described in terms of diffusive control mechanisms.

Light affects CO₂ diffusion by initiating photosynthesis, which removes CO₂ at the chloroplast and establishes a diffusion gradient. Light also triggers stomatal opening, thereby sharply decreasing the diffusive resistance. However, intense radiation can cause desiccation of stomatal guard cells, a mechanism whereby the diffusive resistance increases.

During illumination, leaf cells have both a source (respiration) and sink (photosynthesis) for CO₂. Respiration in some species appears to be greatly stimulated by light. This additional internal CO₂ flux is a possible reason for a lower efficiency of energy utilization than in species whose respiration is not enhanced by light.

Physiological growth responses or movements often occur that position leaves in the light. Plants lacking this capability are often excluded in ecological succession in nature.     

On-line decision support for take-off runway scheduling with uncertain taxi times at London Heathrow airport

This paper addresses the challenge of building an automated decision support methodology to tackle the complex problem faced every day by runway controllers at London Heathrow Airport. Aircraft taxi from stands to holding areas at the end of the take-off runway where they wait in queues for permission to take off. A runway controller attempts to find the best order for aircraft to take off. Sequence-dependent separation rules that depend upon aircraft size, departure route and speed group ensure that this is not a simple problem to solve. Take-off time slots on some aircraft and the need to avoid excessive delay for any aircraft make this an even more complicated problem. Making this decision at the holding area helps to avoid the problems of unpredictable push-back and taxi times, but introduces a number of complex spatial constraints that would not otherwise exist. The holding area allows some flexibility for interchange of aircraft between queues, but this is limited by its physical layout. These physical constraints are not usually included in academic models of the departure problem. However, any decision support system to support the take-off runway controller must include them. We show, in this paper, that a decision support system could help the controllers to significantly improve the departure sequence at busy times of the day, by considering the taxiing aircraft in addition to those already at the holding area. However, undertaking this re-introduces the issue of taxi time uncertainty, the effect of which we explicitly measure in these experiments. Empirical results are presented for experiments using real data from different times of the day, showing how the performance of the system varies depending upon the volume of traffic and the accuracy of the provided taxi time estimations. We conclude that the development of a good taxi time prediction system is key to maximising the benefits, although benefits can be observed even without this.     

Variability across sources of performance ratings: Further evidence.

33 1st-yr graduate students (aged 21–55 yrs) completed a simulated counseling interview. Self-, peer, and supervisor ratings were obtained for the simulated interviews using 7 measures of counseling performance. A multiple analysis of variance (MANOVA) indicated statistically significant differences among self-, peer, and supervisor ratings. Analyses also showed significant differences on 4 of the 7 dependent measures. Implications for training are discussed. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Advancing mental health in political places.

The author describes his career as a psychologist serving in elected office. He found that by his attending to individual concerns, supporting community consensus on key issues, playing the outsider role, leading an issue individually, and calling media attention to a problem, city hall could be moved to action. In the state legislature, the author serves in the minority but has made an impact by amending legislation, sponsoring less controversial bills, or generating enough public support for a bill that the majority advances its own similar bill. He identified the following mental health needs in Ohio: better understanding by legislators of the nature and impact of mental illness, adequate funding, mental health parity legislation, and more effective advocacy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)