Sized papers, measurements

In this paper we report on the results of size distribution measurements of cloud samples from three coral surface bursts and one silicate surface burst and present the results of the calculations of the sedimentation correction. 

Several areas in which chemical measurement technologies have become available and/or refined for airborne applications have been reviewed in this paper. It is a selective review and many important meteorological and cloud physics measurement capabilities of relevance to atmospheric chemistry and acid deposition (e.g., measurement of cloud liquid water content) have been ignored. In particular, we have not discussed particle size spectra measurements for various atmospheric condensed phases (aerosols, cloud droplets and precipitation). Further improvements in chemical measurement technologies can be anticipated especially in the areas of free radicals, oxidants, organics, and S02 and N02 at very low levels. Nevertheless, major incremental improvements in the understanding of acid deposition processes can be anticipated from the continuing airborne application of the techniques described in this review. 

After the first cose has been rolled up to fit the gauge, it may be unrolled and the paper measured. Future pieces of the same quire of paper can then be cut of the right size at once, so that the case will fit the gauge without further trouble. 

D. M. Ruthven and K. F. Loughlin (University of New Brunswick, Fredericton, N. B., Canada) We would like to re-emphasize the significance of the effects of crystal size distribution in the analysis of sorption curves. The variations in diffusivity which are reported in this paper show precisely the trend which is to be expected if the effect of crystal size distribution is considered. We feel sure that if crystal size distribution measurements are available, it should be possible to obtain the correct values of diffusivity using the type of analysis which we presented in our comment on the paper of Kondis and Dranoff. 

The use of transmission electron microscopy in heterogeneous catalysis centers around particle size distribution measurement, particle morphology and structural changes in the support. Consideration is given to the limitations of conventional electron microscopy and how modifications to the instrument enable one to conduct in-situ experiments and be in a position to directly observe many of the features of a catalyst as it participates in a reaction. In order to demonstrate the power of the in-situ electron microscopy technique examples are drawn from areas which impact on aspects of catalyst deactivation. In most cases this information could not have been readily obtained by any other means. Included in this paper is a synopsis of the methods available for preparing specimens of model and real catalyst systems which are suitable for examination by transmission electron microscopy. 

The participants in this symposium addressed many of these problems. Methods for characterizing size and chemical composition by size were discussed, and several models of metal and virus adsorption were presented. Modeling particulate dynamics in rivers and the ocean provided new insights into the fate of contaminants associated with particulates. Papers on applications of size distribution measurements for selection, process modeling, and control of solid/liquid separation processes demonstrated the analytical value of particle counting compared to cumulative measurements of particulate concentration. 

Site and Application Procedures. The orchard site and air application equipment were the same as described by Currier (1982). In 1980, ground applications were made with an Ag-Tech low volume air blast sprayer, calibrated to deliver 187 1/ha, and in 1981, with a Kinkelder low volume air blast sprayer calibrated to deliver 94.6 1/ha. From previous studies of MacCollom et al ( ) and Currier ( ) it was known that the air application gave a median droplet size diameter of 100 to 150 pm. Estimation of particle size, as measured on water sensitive paper, for ground equipment was 75 to 110 pm. Application rates for captan 80W in both years was 3.12(AI) Kg/ha, and for carbaryl 80S, 2.24(AI) kg/ha. 

Figure 7.17. Penetration rate, measured using the Bristow wheel as function of the advancing water contact angle for different AKD sized paper grades...

Figure 7.44. AFM images of (a) a glossy and (b) a matt paper with a scan size of 4 x 4 pm x- and y-axes, 1.000 pm/division z-axis, 1000 nm/division. Roughness data for the same papers measured by the white-light interferometric technique are provided in Figure 7.45. The same paper grades are also used in the spreading experiments shown in Figure 7.36...

Lin and Phillies in a series of three papers measured Dp of polystyrene spheres in aqueous nonneutralized poly acrylic acid (PAA)(8-10). Lin and Phillies(8) report Dp of nominal 38 nm carboxylate-modified spheres in solutions of 300 kDa PAA at polymer concentration 0.37 < c < 171 g/1 and a range of temperature. At each polymer concentration. Dp tracks T/rj with reasonable accuracy. In a further study, Lin and Phillies(9) compared Dp of probe spheres of various sizes (radius 20.4-1500 nm) in 300 kDa PAA for 0 < c < 145 g/1 polymer. As seen in Figure 9.2, for each probe Dp/Dpo falls markedly with increasing c, for large spheres by as much as three orders of magnitude. For each probe, Dp(c) had a stretched-exponential concentration dependence. The apparent hydrodynamic radius rh (Figure 9.2) of... 

In a couple of particular papers, the application of LD particle sizer to measure the size distribution of micro-bubbles are mentioned. Couto et al. [44] performed micro-bubble size distribution measurements by the laser diffraction technique. It was concluded that the size distribution of micro-bubbles generated for the dissolved air flotation process could be assessed on a fast and reliable way by the application of the laser diffraction technique. The micro-bubble size distribution was measured by the Mastersizer 2000 SM equipment from Malvern Instruments, UK. The instrument specifications state that analysis in the particle range from 0.1 to 2000 ttm is possible, and the data interpretation computations could either be performed by use of the... 

Bowen, P., Humphy-Baker, R., Herard, C, Particle Size Distribution Measurement of Regular Anisotropic Particles - Cylinders and Platelets, in Proc. World Congress Part. Technol. 3, Brighton, 1998, Paper No.29. 

This paper deals with the control of weld depth penetration for cylinders in gold-nickel alloy and tantalum. After introducing the experimental set-up and the samples description, the study and the optimization of the testing are presented for single-sided measurements either in a pulse-echo configuration or when the pump and the probe laser beams are shifted (influence of a thermal phenomenon), and for different kind of laser impact (a line or a circular spot). First, the ultrasonic system is used to detect and to size a flat bottom hole in an aluminium plate. Indeed, when the width of the hole is reduced, its shape is nearly similar to the one of a slot. Then, the optimization is accomplished for... 

Starches used to increase the internal strength of paper as measured by tensile, edge cmsh resistance, Mullen burst, and Scott bond strength are added at the wet end, whereas starch used to increase surface strength as measured by pick and resistance to Hnting are added at the size press. 

Test Methods. The test methods used for water or oil repeUency are quite varied, in accordance with paper or paperboard type and end use. Two tests commonly used to measure water repeUency, the Hercules Size Test and the COBB Test, as weU as others have been summarized (55,69,70). 

Ahlvik, Peter, Leonidas Ntziachristos, forma Keskinen, and Annele Virtaiien. Real Time Measurements of Diesel Particle Size Distribution with an Electrical l.ow Pressure Impactor. SAL Technical paper 980410. Reprinted from General Emissions (SP-13.3,5). lnternation.al Congress and Exposition, Detroit, February, 23-26 (1998). 

About 5 ml of sample is withdrawn for every 4-6 hours. The absorbance reading of the sample at 580 nm was measured using a Hitachi U-2000 spectrophotometer. The sample is filtered in a vacuum through Whatman filter paper with a pore size of 2.5 pin and diameter of 47 mm. The dry weight of cells is measured to monitoring microbial cell population and cell density. A plot of optical density reading from the spectrophotometer against cell dry... 

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