Soot concentration and temperature measurements in co-annular, nonpremixed CH4/air laminar flames at pressures up to 4 MPa

Laminar nonpremixed methane-air flames were studied over the pressure range of 0.5 to 4 MPa using a new high-pressure combustion chamber. Flame characterization showed very good flame stability over the range of pressures, with a flame tip rms flicker of less than 1% in flame height. At all pressures, soot was completely oxidized within the visible flame. Spectral soot emission (SSE) and line-of-sight attenuation (LOSA) measurements provided radially resolved measurements of soot volume fraction and soot temperature at pressures from 0.5 to 4.0 MPa. Such measurements provide an improved understanding of the influence of pressure on soot formation and have not been reported previously in laminar nonpremixed flames for pressures above 0.4 MPa. SSE and LOSA soot concentration values typically agree to within 30% and both methods exhibit similar trends in the spatial distribution of soot concentration. Maximum soot concentration depended on pressure according to a power law, where the exponent on pressure is about 2 for the range of pressures between 0.5 and 2.0 MPa, and about 1.2 for 2.0 to 4.0 MPa. Peak carbon conversion to soot also followed a power-law dependence on pressure, where the pressure exponent is unity for pressures between 0.5 and 2.0 MPa and 0.1 for 2.0 to 4.0 MPa. The pressure dependence of sooting propensity diminished at pressures above 2.0 MPa. Soot concentrations measured in this work, when transformed to line-integrated values, are consistent with the measurements of Flower and Bowman for pressures up to 1.0 MPa [Proc. Combust Inst. 21 (1986) 1115-1124] and Lee and Na for pressures up to 0.4 MPa [JSME Int. J. Ser. B 43 (2000) 550-555]. Soot temperature measurements indicate that the overall temperatures decrease with increasing pressure; however, the differences diminish with increasing height in the flame. Low down in the flame, temperatures are about 150 K lower at pressures of 4.0 MPa than those at 0.5 MPa. In the upper half of the flame the differences reduce to 50 K.     

The economics of chipping logging residues at roadside: A study of three systems

Three biomass chipping operations of roadside logging residues were studied in New Brunswick and Maine. Two of the operations used a skidder-loader to form the roadside debris into larger piles closer to the road edge prior to chipping. Average chipping productivity ranged from 8.l oven dry Mg per Productive Machine Hour (OdMg PMH⁻¹) to 28.2 OdMg PMH⁻¹ depending on the site and chipping system used. The average cost of chips on board the chip vans ranged from $15.29 CAN OdMg⁻¹ to $25.86 CAN OdMg⁻¹. The chips were transported to three energy plants in Maine. One-way hauling distances varied from 29 km to 105 km.     

Novel aspects of wet milling for the production of microsuspensions and nanosuspensions of poorly water-soluble drugs

Micronization and nanoparticle production of poorly water-soluble drugs was investigated using single wet milling equipment operating in the attritor and stirred media modes. The drug particles in the median size range of 0.2?2??m were prepared by changing the milling mode and operating conditions of a Micros mill with a purpose of elucidating the dynamics of the wet milling process. It was determined that particle breakage due to mechanical stresses and aggregation due to insufficient stabilization are two competing mechanisms which together control the wet milling dynamics of the poorly water-soluble drugs. The study in the attritor mode using four different classes of stabilizers with six drugs indicated that steric stabilization worked better than electrostatic stabilization for the drugs studied. In addition, the existence of different minimum polymer concentrations for the stabilization of microsuspensions and nanosuspensions was indicated. The major role of a non-ionic polymer during the production of fine particles is its stabilization action through steric effects, and no experimental evidence was found to support the so-called Rehbinder effect. Periodic addition of the polymer as opposed to the addition of the polymer at the start of milling process was introduced as a novel processing method. This novel method of polymer addition provided effective stabilization and breakage of drug particles leading to a narrower and finer particle size distribution. Alternatively, it may allow shorter processing time and lower overall power consumption of the milling process for a desired particle size.     

Noninvasive estimation of dynamic pressures in vitro and in vivo using the subharmonic response from microbubbles

The purpose of this study was to develop and validate a noninvasive pressure estimation technique based on subharmonic emissions from a commercially available ultrasound contrast agent and scanner, unlike other studies that have either adopted a single-element transducer approach and/ or use of in-house contrast agents. Ambient pressures were varied in a closed-loop flow system between 0 and 120 mmHg and were recorded by a solid-state pressure catheter as the reference standard. Simultaneously, the ultrasound scanner was operated in pulse inversion mode transmitting at 2.5 MHz, and the unprocessed RF data were captured at different incident acoustic pressures (from 76 to 897 kPa). The subharmonic data for each pulse were extracted using band-pass filtering with averaging, and subsequently processed to eliminate noise. The incident acoustic pressure most sensitive to ambient pressure fluctuations was determined, and then the ambient pressure was tracked over 20 s. In vivo validation of this technique was performed in the left ventricle (LV) of 2 canines. In vitro, the subharmonic signal could track ambient pressure values with r(2) = 0.922 (p < 0.001), whereas in vivo, the subharmonic signal tracked the LV pressures with r(2) > 0.790 (p < 0.001) showing a maximum error of 2.84 mmHg compared with the reference standard. In conclusion, a subharmonic ultrasound-based pressure estimation technique, which can accurately track left ventricular pressures, has been established.     

Factors associated with food workers working while experiencing vomiting or diarrhea

This study sought to determine the frequency with which food workers said they had worked while experiencing vomiting or diarrhea, and to identify restaurant and worker characteristics associated with this behavior. We conducted interviews with food workers (n=491) and their managers (n=387) in the nine states that participate in the Centers for Disease Control and Prevention's Environmental Health Specialists Network. Restaurant and worker characteristics associated with repeatedly working while experiencing vomiting or diarrhea were analyzed via multivariable regression. Fifty-eight (11.9%) workers said they had worked while suffering vomiting or diarrhea on two or more shifts in the previous year. Factors associated with workers having worked while experiencing vomiting or diarrhea were (i) high volume of meals served, (ii) lack of policies requiring workers to report illness to managers, (iii) lack of on-call workers, (iv) lack of manager experience, and (v) workers of the male gender. Our findings suggest that policies that encourage workers to tell managers when they are ill and that help mitigate pressures to work while ill could reduce the number of food workers who work while experiencing vomiting or diarrhea.     

Conjugated Polymers of Intrinsic Microporosity (C‐PIMs)

Conjugated microporous polymers (CMPs) have shown great potential for energy and environmental issues, however, poor solubility and processability of most of these materials limit their applications. Herein, a range of linear conjugated polymers of intrinsic microporosity (C‐PIMs) is reported, combining for the first time the properties of conjugated microporous polymers, such as tunable electronic properties and compositional variation, with those of linear polymers of intrinsic microporosity (PIMs) allowing for solution processability and film formation. These soluble materials have a number of potential applications, for example as components in devices where large, porous interfaces are combined with extended electronic conjugation.     

Comparison of three monoclonal antibody pools for the detection of respiratory viral antigen in respiratory secretions

The aim of this study was to compare the sensitivities of commercial monoclonal antibody pools to be used as an initial rapid screen for detection of viral antigens in respiratory secretions. The availability of commercial monoclonal antibodies has dramatically improved the detection of viruses by immunofluorescence techniques in exfoliated cells obtained from respiratory secretions. Several companies have recently introduced monoclonal antibody pools to detect the presence of respiratory viruses in a single preparation. Ninety-four stored slide preparations that had previously been examined by individual monoclonal antibodies were tested using three commercial monoclonal antibody pools produced by Sanofi (UK), Dako (UK), and Quadratech (UK). These monoclonal antibody pools had a sensitivity of 79.6%, 90.9%, and 100%, respectively, when compared with the original results. The overall intensity of immunofluorescence was also examined.     

Effect of Microstructure on the Tribological and Mechanical Properties of CuO-Doped 3Y-TZP Ceramics

Dense 8 mol% CuO-doped 3Y-TZP ceramics were prepared by pressureless sintering for 8 h at 1500° and 1550°C, respectively. Transmission electron spectroscopy revealed that the ceramic sintered at 1500°C exhibits grain boundaries free of any amorphous phase, while crystalline copper-oxide grains were found in the zirconia matrix, whereas the sample sintered at 1550°C contains a Cu-rich amorphous grain boundary layer. The tribological behavior of these materials was tested under dry-sliding conditions using a pin-on-disk tribometer. The material sintered at 1500°C showed self-lubrication resulting in a low coefficient of friction ( f ) of 0.2–0.3 and a low specific wear rate ( k ) ≪ 10⁻⁶ mm³·(N·m)⁻¹. In contrast, the material sintered at 1550°C showed poor tribological behavior ( f =0.8–0.9; k ≫ 10⁻⁶ mm³·(N·m)⁻¹ under the same conditions. The difference in the tribological behavior of these two materials was interpreted on the basis of mechanical properties and microstructural characteristics.     

President’s column.

Presents remarks from the president of the APA's Division 13 (Division of Consulting Psychology). The author discusses the second annual Colorado conference on consulting to corporations and business; the planning for Division activities at the APA convention in Los Angeles; and the affect of health reform on consulting psychology and consulting psychologists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The mechano-sorptive behavior of flexible water-blown polyurethane foams

Samples of flexible water-blown slabstock polyurethane foams were compressed under constant load to study the effects of cycling moisture content on creep behavior and compare this behavior with the creep response where either a constant high or low moisture environment existed at the same temperature. Three sets of foams were tested: (1) 4 pph water content slabstock foam; (2) 5 pph water content slabstock foam; and (3) 2 pph water content molded foam. As the moisture conditions were cycled from low to high humidity while maintaining constant temperature in an environmental chamber, the compressive strain increased in subsequent steps with larger increases observed during the desorption portion of the humidity cycling. All three sets of foams showed similar behavior at a given temperature. At a temperature of 40°C, the strain levels under cyclic moisture conditions surpassed those levels observed at the highest constant relative humidity. During the first absorption step, the creep level increased. During any subsequent absorption step, the creep level either increased very little or none at all. Finally, during any desorption step, the creep level increased. This overall phenomenon of enhanced creep under cyclic moisture levels is attributed to water interacting with the hydrogen bonded structure within the foam. These hydrophillic interactions, principally promoted within the hard segment regions due to high hydrogen bonding, are disrupted causing slippage and increased in strain. As the foam is rapidly dired, regions of free volume are induced by the loss of water thus causing further increases in strain Prior to the reestablishment of well ordered hydrogen bonding. Further support to this proposition was given by the results obtained at a temperature of 90° C where it is well known that hydrogen bonds are much more mobile. Here, the strain levels under cyclic moisture conditions were nearly the same as those under constant high relative humidity. Weakening of the hydrogen bonds by means such as increased temperature resulted in similar strain levels to those under cyclic moisture levels. © 1993 John Wiley & Sons, Inc.