Diffusion Deposition on a Fiber in Nontransverse Flow

The effect of a nontransverse flow on the diffusional deposition of particles in an aerosol on a cylindrical fiber is investigated. The aerosol is transported by a slow laminar flow whose mean direction is at an arbitrary angle ? to the axis of the cylinder. The particle concentration and the subsequent deposition rate on a cylinder for such a flow are found by using the first two terms of the asymptotic solution in terms of the diffusion boundary layer thickness. This is inversely proportional to the cube root of the Peclet number, a parameter which is large for many problems of practical importance. For a given flow angle ? an expression for the diffusion efficiency η(?) is obtained. Under the assumption that the angular distribution of the fibers is uniform, a relation for the average value (η) for the diffusion efficiency is also derived. These formulas are generalizations of the results of Natanson and Stechkina for the diffusion efficiency in the case of purely transverse flow and with those of Banks and Kurowski for the mean flow at a small angle to the fiber     

Monitory Democracy as Citizen-driven Participatory Planning: The Urban Politics of Redwatch in Sydney

This article analyses a case of citizen-driven participation in urban planning in Sydney, Australia. Drawing on a case study of the local resident action group REDWatch the analysis is undertaken within the context of the hybrid forms of technocratic, participatory and neoliberal planning that are operating in the New South Wales planning system. Framed by the concept of monitory democracy, the analysis explores the four key features of monitory forms of civic action: (1) monitoring powerful social actors; (2) encouraging difference, disagreement, debate and change; (3) making formal power structures more transparent and accountable; and (4) fostering new forms of informal political power. The findings demonstrate that analyses of formal community consultation events and participatory planning policies are far too narrow to determine the civic utility of citizen participation in planning. Expanding the analytical borderland beyond the formal structures of the planning system exposes important informal citizen participation practices that are operating from outside of planning systems. Unlike formal state-driven participatory planning events and policies, these informal citizen-driven participatory planning practices can deal with planning hybridity and conflict, which are increasingly central to many contemporary planning systems.     

Cost-effectiveness of renewable electricity policies

We analyze policies to promote renewable sources of electricity. A portfolio standard (RPS) raises electricity prices and primarily reduces gas-fired generation. A knee of the cost curve exists between 15% and 20% goals for 2020 in our central case, and higher natural gas prices lower the cost of greater reliance on renewables. A renewable energy production tax credit lowers electricity price at the expense of taxpayers, which limits its effectiveness in reducing carbon emissions, and it is less cost-effective at increasing renewables than a portfolio standard. Neither policy is as cost-effective as a cap-and-trade policy for achieving carbon emission reductions.     

Inactivation of Salmonella typhimurium DT 104 in UHT whole milk by high hydrostatic pressure

Cell suspensions of Salmonella typhimurium DT 104 in ultra-high temperature (UHT) whole milk were exposed to high hydrostatic pressure at 350, 400, 450, 500, 550, and 600 MPa at ambient temperature (ca. 21 degrees C). Tailing was observed in all survival curves, and sigmoidal survival curves were observed at relatively high pressure (500-600 MPa). Four modeling methods (linear and nonlinear including Weibull, modified Gompertz, and log-logistic models) were fitted to these data at 500, 550, and 600 MPa. Performances of the modeling methods were compared using mean square error (MSE). The linear regression model at these three pressure levels had a mean square error (MSE) of 1.260-2.263. Nonlinear regressions using Weibull, modified Gompertz, and log-logistic models had MSE values in the range of 0.334-0.764, 0.601-1.479, and 0.359-0.523, respectively. Modeling results indicated that first-order kinetics could not accurately describe pressure inactivation of S. typhimurium DT 104 in UHT milk; the log-logistic model produced the best fit to data.     

Sensitivities of foodborne pathogens to pressure changes

Eight foodborne pathogens were suspended in ultrahigh-temperature whole milk and treated at pressure levels of 0.1 to 690 MPa at 21.5 degrees C for 10 min. There was no clear trend in pressure resistance between gram-negative and gram-positive organisms. The order of the single strains tested, from most to least pressure sensitive, was Vibrio parahaemolyticus < Yersinia enterocolitica < Listeria monocytogenes < Salmonella enterica serovar Typhimurium < S. enterica serovar Enteritidis < Escherichia coli O157:H7 approximately equal to Staphylococcus aureus < Shigella flexneri. For each organism there existed a pressure range in which log(number of survivors) had a near linear relationship when plotted versus treatment pressure level. In this study, a decimal reduction pressure (Dp) value was defined and used to measure the sensitivity of these pathogens to pressure changes. L. monocytogenes and V. parahaemolyticus were most sensitive to pressure changes, and S. flexneri was most resistant. The D(P) values were 16.3 MPa for L. monocytogenes, 21.7 MPa for V. parahaemolyticus, and 127.0 MPa for S. flexneri. The most pressure-resistant gram-negative bacterium, S. flexneri, and most pressure-resistant gram-positive bacterium, S. aureus, were treated at 50 degrees C and pressures of 0.1 to 650 MPa for 10 min. High temperature considerably enhanced pressure inactivation of these two organisms and affected their sensitivities to pressure changes. The effect of treatment time on the D(P) values of L. monocytogenes and V. parahaemolyticus was also determined, and it was found that it did not significantly affect their D(P) values.     

Dry aging of beef in a bag highly permeable to water vapour

The objective of this experiment was to compare traditional dry aging of beef with a novel technique of dry aging in a highly moisture-permeable bag. Four equal-sized sections from paired beef strip loins were dry aged traditionally, unpackaged, or packaged in the experimental bag for 14 or 21 d at 3 °C. No differences (P > 0.05) were noted for pH, moisture, fat, total plate counts, cook loss, shear force, or any measured sensory attribute between the two aging treatments after either aging period. After 21 d, however, dry aging in the bag (versus traditional dry aging) decreased (P < 0.05) weight loss during aging, trim loss after aging, and yeast counts on lean tissue and increased lactic acid bacteria counts (P < 0.05) on adipose and lean tissue. Dry aging in a highly moisture-permeable bag is feasible, will positively impact yields and reduce microbial spoilage, and will have no negative impact on product quality.     

Dissociating the anti-fear effects of septal and amygdaloid lesions using two pharmacologically validated models of rat anxiety.

Compared the effects of septal and amygdaloid lesions in 2 models of rat anxiety. Septal lesions decreased burying behavior in the shock-probe burying test and increased open-arm exploration in the elevated plus-maze test, whereas amygdaloid lesions produced neither of these anxiolytic effects. However, amygdaloid lesions increased rats' contacts of the electrified probe, an anxiolytic effect not produced by septal lesions. Each of these distinct, anxiolytic effects of septal or amygdaloid lesions were displayed together in animals with lesions of both structures. Furthermore, the magnitude of these anxiolytic effects after combined lesions were comparable to their magnitude after individual lesions. Taken together, these results suggest that the amygdala and the septum independently control the expression of different fear-related behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)