Particle control

D. W. Cooper, "Fiue Particle Control by Electrostatic Augmentation of Existing Methods," Preprint 75-02.1, 68th APPCA Annual Meeting Boston, Mass., June 15—20, 1975. 

ESPs), and some of the previously discussed novel devices. Series combinations of control devices may be necessary to achieve the required level of particulate matter emission. A commonly used system is a multiple cyclone followed by a fine-particle control system, such as a baghouse, scrubber, or ESP. 

R. P. Donovan. Particle Control for Semiconductor Manufacturing. New York M. Dekker, 1990. 

Equation 1 has as its basis the concept that diffusion, either through pores or to the gross surface of the catalyst particle, controls the reaction rate. When the control is strictly by the gas film surrounding the catalyst, one would have to convert Equation 1 to... 

Fraser, M. P., and G. R. Cass, Detection of Excess Ammonia Emissions from In-Use Vehicles and the Implications for Fine Particle Control, Environ. Sci. Technol., 32, 1053-1057 (1998). 

Thus, in fixed beds, the critical parameters are the contact time and particle size. Particle size should be kept the same, since it is well known that it affects the rate of adsorption and ion exchange. However, the role of particle size is more complicated because it also affects the pressure drop. For this reason, it is desirable to use a narrow particle size range during design, as the large particles control the uptake rate, whereas the small ones control the pressure drop (McKetta, 1993). 

Oglesby, S. Jr., "A Survey of Technical Information Related to Fine Particle Control", Electric Power Research Institute, EPRI 259, PB 242-383, Section III, Health Effects of Fly Ash Inhalation, (April 1975). 

Harrison RM, Giorio C, Beddows DC, Dall Osto M (2010) Size distribution of air-borne particles controls outcomes of epidemiological studies. Sci Total Environ 409 289-293... 

Coal contains most of the elements of the periodic table, the majority of which are present in concentrations of 100 ppm or less. Many of these trace elements are toxic to plant and animal life, even at low levels. Because U.S. power plants consune on the order of 600 million tons of coal annually for the production of electricity (1), coal combustion can mobilize thousands of tons of potentially hazardous trace elements into the environment each year. Due to the large quantities of coal combusted, even trace amounts of toxic elements present in the coals can accumulate to hazardous levels. Also, potentially deleterious effects of particulate emissions from coal combustion may be enhanced since many trace elements are surface-enriched (2) and concentrate preferentially in the smaller, more respirable particle sizes (3). Substantial amounts of some elements, such as As, Hg, and Se, are in the vapor phase in flue gases from coal combustion and are essentially unaffected by most particle control devices. Aside from the potential detrimental environmental aspects, trace elements in coal can pose adverse technological... 

Fly Ash. Fly ash samples were collected directly from the hoppers of the cyclone and electrostatic precipitator used for particle control. 

Dilution of sample—The dilution of concentrated samples may lead to large errors in counting. Concentrated samples flocculate and settle at higher rates than dilute samples. Consequently, the portions transferred by pipette are not always representative. However, this in itself may not be a serious drawback except when the samples are taken for long periods of time. The dilution of samples should proceed to a point where the average count per one-fourth field is greater than 20 and less than 40 particles. Control samples may be relatively free from particles, but as a rule they average from 4 to 10 per one-fourth field. 

The amount of the dispersant and the size of the particles control the viscosity of the slurry. The selection of the viscosity will depend on the particular reactor design and the economics of the process. Tests have shown that the mineral oil can be recovered from the hydroxide slurry and reused. The mineral oil remains unchanged through the reaction. 

Keywords microgel particles, core-shell particles, controlled release, triggered release 1. Introduction... 

Interactions between soluble polymer and colloidal particles control the behavior of a large number of chemical products and processes and, hence, their technological viability. These dispersions have also attracted considerable scientific interest because of their complex thermodynamic and dynamical behavior—stimulated by the synthesis of novel polymers, improved optical and scattering techniques for characterization, and a predictive capability emerging from sophisticated statistical mechanical theories. Thus, the area is active both industrially and academically as evidenced by the patent literature and the frequency of technical conferences. 

To provide control of microbial, pyrogen, and particles controls over the production environment are essential. The facility concerns encompass the entire building, but the most relevant components are those in which production materials are exposed to the environment. 

The product contact surfaces in this environment are typically removed for cleaning however, in some installations, the sterilization, transfer, and reinstallation of the component feed hoppers present such difficulty that these systems are decontaminated in situ with a sporicidal agent, rather than removed after each use. These units should still be removed for cleaning and sterilization on a validated periodic basis to prevent the buildup of residues that might impact their in-situ decontamination or create particle control problems. All other product contact surfaces should be sterilized prior to each use. Nonsterilized items should not be allowed to enter the ISO 5 portion of the fill zone, and sanitization is essential for all nonproduct surfaces in the fill zone, as well as the surrounding background environment. 

Where firms have introduced unidirectional air systems in preparations and compounding areas for particle control, there is often the temptation to expect these areas to meet the same microbial limits that these locations might attain in the aseptic core. This temptation should be resisted to avoid unnecessary sampling and deviations associated with expecting these environs to meet the conditions of aseptic areas where sanitization frequency, background environment, and most importantly personnel gowning are far superior to that found in the less clean locales [33]. 

The investigation of molecular behavior in the divertor plasmas is important for establishment of heat and particle control in the tokamak. For attached divertor plasmas, where the electron temperature is high and the molecules... 

G. B. Beestman, Microencapsulation of Solid Particles, Controlled Release Delivery Systems, Marcel Dekker, Inc., USA, 1999, pp.31-54. 

V.B. Menon and R.P. Donovan, Review of Particle Control Methods During Wet Chemical Cleaning of Silicon Wafers, in Semiconductor Qeaning Technology/1989, PV90-9, eds. J. Ruzyllo and R.E. Novak, The Electrochemical Society, Inc., 10 S. Main St., Pennington, NJ 08534-2896 (1990), p. 167. 

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