Size and Generation Rate of Sidestream Cigarette Smoke Particles

Sidestream cigarette smoke generated using an automatic smoking machine (SEM-II) and Kentucky 2R1 reference cigarettes was analyzed for particle generation rate and size distribution. Part of the sidestream smoke was sampled with an Andersen Cascade Impactor, following dilution with about 29 to 54 liters/min of laboratory air. The remaining sidestream smoke was further diluted 1,000-fold with vapor phase from filtered sidestream smoke before analysis with an Electrical Aerosol Analyzer and Condensation Nuclei Counter. The smoking parameters of primary dilution ratio and puff pressure were varied in the experiments. The number median diameter of sidestream cigarette smoke was about 0.10 μm, and the mass median diameter was typically 0.16 μm, about half the size of fresh mainstream smoke. Additionally, the size distribution of sidestream smoke was significantly broader than that of mainstream smoke. The particle generation rate of sidestream smoke depended on smoking conditions and varied from 1.4 × 10⁹ to 3.9 × 10⁹ particles/s. The equivalent total particulate matter of sidestream smoke based on the Electrical Aerosol Analyzer measurements varied from 1.3 to 2.3 mg/cigarette, whereas it was 6.0 to 9.6 mg/cigarette based on the Andersen Cascade determinations. Reasons for these differences are not definitive at this time.     

The Politics of Enacting State Legislation to Enable Local Impact Fees: The Pennsylvania Story

Although Lillydahl et al. advocate the passage of state enabling legislation to clearly establish municipal authority to collect impact fees, the literature does not provide guidance for achieving this goal. The evolution of Pennsylvania's statute suggests that the following factors affect a bill's content and success: (1) the proportion of legislative districts confronting the problems of rapid growth; (2) the ability of interest groups to conduct effective grass roots campaigns; (3) the use of floor amendments to “catch the opposition off guard;” (4) effective communication between a bill's negotiators and its supporters; and (5) the appearance of flexibility on the part of the bill's supporters.     

AN EXAMINATION OF ASTM PROCEDURES FOR DETERMINING SULFUR FORMS IN COAL

ABSTRACT

Several raw coals of various ranks were used to examine the effects of some of the variations in ASTM procedures on analytical results obtained for total sulfur and sulfur forms. ASTM procedures were also used to determine pyritic sulfur in two coals cleaned by selective agglomeration processes.In addition, organic sulfur values obtained by the indirect ASTM procedure were compared to those obtained directly by leaching coal with hot HNO3 followed by total sulfur determinations on the coal residue.

Differences in the ASTM leaching procedure with HNO3 did not significantly affect the pyritic sulfur results for any of the coals. However, small differences between the referee (leaching coal with HNO3) versus alternate (leaching coal ash with HCl) ASTM procedures for determining pyritic sulfur were observed.Neithei: procedure was consistently higher than the other.     

Detection of shape deviations and measurement errors by a point cloud analysis

For the enhancement of technical workpiece surfaces with even larger dimensions, the application of microstructures on the surface is an appropriate way to improve the fitness for use without changing the properties of the basic material. Considering the extremely small dimensions of approximately 5–20 μm of the applied microstructure, the quality assurance faces new challenges related to the obtainment and evaluation of measurement data. This article presents an approach for the automated detection of shape deviations of a microstructure, as well as the detection of measurement errors during an optical or tactile measurement. The explained algorithm is based on the analysis of the measurement points within a point cloud by observing the distances between the single points. To illustrate the disturbance in the measurement point cloud every point is evaluated by an adaptive weighting function. The weighting of each measurement point can then be visualized by plotting the whole point cloud according to a corresponding color scale. The suitability of the point cloud analysis is demonstrated by the examples of a shape deviation (artificial groove) and a measurement error, occurred by measurement via confocal microscopy.     

Design and Calibration of the EPA PM2.5 Well Impactor Ninety-Six (WINS)

The EPA well impactor ninety-six (WINS) was designed and calibrated to serve as a particle size separation device for the EPA reference method sampler for particulate matter under 2.5     

Investigation of solid oxide fuel cell sealing behavior under stack relevant conditions at Forschungszentrum Jülich

Hermetic sealing is a key requirement for the operation of solid oxide fuel cell (SOFC) stacks in a system environment. The sealant material has to withstand stresses due to mechanical loading, mismatch in thermal expansion coefficient and thermal gradients that arise during operation. Based on leakage tests performed at Forschungszentrum Jülich it was obvious that stacks, having been operated successfully in a furnace, are not necessarily usable in a system, e.g. because of deviating pressure differences and temperature gradients. Thorough investigations including stack and stack dummy tests, and finite element modeling (FEM) were performed to get a comprehensive understanding of the various parameters, influencing the leak tightness of the sealing material. It was found that even small temperature differences especially in the area of gas and air manifolds can create excessively high tensile stresses. Based on initial FEM analyses, a better understanding of the problem has been obtained and a tool was developed that can assist in the design of more robust stacks. These investigations and modeling activities will be continued with a main focus on thermal cycling, which is the next step in the list of requirements.     

Particle Collection Efficiency for Nylon Mesh Screens

Nylon mesh screens, unlike metal screens, are attractive as a collection substrate for nanoparticles because they can be digested or ashed prior to chemical analysis. A theoretical single-fiber efficiency expression developed for wire-mesh screens was evaluated for estimating the collection efficiency of 11–300 nm particles for nylon mesh screens. Pressure drop across the screens, the effect of particle morphology (spherical and highly fractal-like) on collection efficiency, and single-fiber efficiency were evaluated experimentally for three pore sizes (60, 100, and 180 μm) at three flow rates (2.5, 4, and 6 Lpm). The pressure drop across the screens was found to increase linearly with superficial velocity. The collection efficiency of the screens was found to vary by less than 4% regardless of particle morphology. Single-fiber efficiency calculated from experimental data was in good agreement with that estimated from theory for particles between 40 and 150 nm but deviated from theory for particles outside this size range. New coefficients for the single-fiber efficiency model were identified that minimized the sum of square error (SSE) between the values estimated with the model and those determined experimentally. Compared to the original theory, the SSE calculated using the modified theory was at least one order of magnitude lower for all screens and flow rates with the exception of the 60-μm pore screens at 2.5 Lpm, where the decrease was threefold.

Copyright 2012 American Association for Aerosol Research     

Changing energy-related behavior: An Intervention Mapping approach

This paper's objective is to apply Intervention Mapping, a planning process for the systematic development of theory- and evidence-based health promotion interventions, to the development of interventions to promote energy conservation behavior. Intervention Mapping (IM) consists of six steps: needs assessment, program objectives, methods and applications, program development, planning for program implementation, and planning for program evaluation. Examples from the energy conservation field are provided to illustrate the activities associated with these steps. It is concluded that applying IM in the energy conservation field may help the development of effective behavior change interventions, and thus develop a domain specific knowledge-base for effective intervention design.     

Optimized parametrization of systems of incidences between rigid bodies

Graphs of pairwise incidences between collections of rigid bodies occur in many practical applications and give rise to large algebraic systems for which all solutions have to be found. Such pairwise incidences have explicit, simple and rational parametrizations that, in principle, allow us to partially resolve these systems and arrive at a reduced, parametrized system in terms of the rational parameters. However, the choice of incidences and the partial order of incidence resolution strongly determine the algebraic complexity of the reduced, parametrized system—measured primarily in the number of variables and secondarily in the degree of the equations.