NaCl particles

Finlayson-Pitts, B. J., M. J. Ezell, and J. N. Pitts, Jr., Formation of Chemically Active Compounds by Reactions of Atmospheric NaCl Particles with Gaseous N205 and CION02, Nature, 337, 241-244 (1989a). 

Calculate the critical radius /y and critical supersaturation Sc. for activation into a cloud droplet of a 10-l5-g NaCl particle. Assume the surface tension is 72 dyn cm-1 and the liquid density is that of water. 

Scattering intensity measured by the pulse height analyzer is related to particle size by calibration with monodisperse latex spheres or nearly mono-disperse NaCl particles. Calibration uncertainties have been studied and discussed (86-91). These studies show that the smallest particles that can be sensed by the ASASP probe are somewhat larger than the 0.12 xm stated by the manufacturer. Similarly, it is reported that detection of particles larger than about 2 xm is unreliable because of attenuation of the laser power. 

Hygroscopic particles grow as water vapour is condensed on them as they pass down the respiratory tract. Tu Knutson (1989) found 50% deposition of 0.35- m NaCl particles inhaled orally. Minimum deposition of NaCl was found at a particle size of 0.075 jum. 

Sample Sample identity Theoretical NaCl particle distribution (pm) Pore size distribution (pm) Theoretical Porosity (%) Measured Porosity (%)... 

Sample Sample identity Theoretical porosity (%) Darcy permeability constant Minimum pore diameter (urn) Median pore diameter (urn) Largest pore diameter (urn) NaCl particle size range (pm)... 

Frank, N.R., M.O.Amdur, and LL.Whittenberger. 1964. A comparison of the acute effects of S02 administered alone or in combination with NaCl particles in the respiratory mechanics of healthy adults. Int. J. Air Water Poll. 8 125-133. 

It may be taken for granted that analysis for all elements on a catalyst support work equally well. We have performed experiments on many different catalysts and have found that elements such as Cl, K, Na, and S are very sensitive to the electron beam. Cl and S appear to volatilize in the vacuum while K and Na move away from the incident beam. This is especially true when the beam is spotted directly onto the particle versus using the less damaging raster mode. Examples of how elemental analyses of a BaS0A, zeolite, and NaCl particles vary as a function of time are shown in Figure 5. 

This equation is given in terms of a constant (3Viry Af Po/ (V2A 7 k )), a function of particle size, a, and a time function. This neck size is an important factor in determining the strength of the ceramic and also its conductivity. The radius of the neck, x, will continue to increase until it has become essentially flat. An experimental study of the sintering of spherical NaCl particles [2, p. 472] shows that this relationship for the neck size is indeed followed for this evaporation condensation mechanism. 

Finlayson-Pitts B. J., Ezell M. J., and Pitts J. N., Jr. (1989) Formation of chemically active chlorine compounds by reactions of atmospheric NaCl particles with gaseous N2O5 and CIONO2. Nature 337, 241-244. 

Knipping E. M. and Dabdub D. (2002) Modeling CI2 formation from aqueous NaCl particles evidence for interfacial reactions and importance of CI2 decomposition in alkahne solution. J. Geophys. Res. 107, doi 10.1029/2001JD000867. 

FIG. l.Low contact force images of NaCl particles (a) before particle removal, and (b) after particle removal. The line in (b) shows the orientation of the linear scan used to remove Particle A, which was subsequently found at Position A. ... 

FIG. 4. SFM image of a region of a substrate cleared of adhering NaCl particles at 55% RH and a contact force of 51 nN. 

In many noncatalytic types a solid product builds up around the reacting core [for example, Na2S04(j) is deposited around the NaCl particles in the last illustration]. This introduces the additional physical processes of heat and mass transfer through a product layer around the solid reactant. A somewhat different form of noncatalytic gas-solid reaction is the regeneration of catalysts which have been deactivated by the deposition of a substance on the interior surface. The most common is the burning of carbon (with air) which has been gradually deposited on catalyst particles used in hydrocarbon reactions. Many of the physical and chemical steps involved here are. the same as those for gas-solid catalytic reactions. The chief difference is the transient nature of the noncatalytic reaction. This type of heterogeneous reaction will be considered in Chap. 14. 

The decay of the number concentration with time at all sizes is evident over the first 12 hours or so in the DMPS measured size distribution. After this there is an obvious onset of nucleation and significant growth followed by decay in the aerosol number. The eycles of particle loss and fresh nucleation is repeated over several days, with no introduetion of precursor gases. The initial concentration of NaCl particles is eomparable to a low atmospheric loading and the nucleation is at a fairly low level. This illustrates the baekground level of aerosol dynamics which is currently experienced. This will improve with inereased scrubbing and cleaning procedures. 

The water molecules evaporate, the salt molecules remain salt can be found at the bottom in the form of NaCl particles all that remains are sodium chloride particles [5]. 

Ionic Bonding and Salt Particles. In his examinations, Hilbing [13] asked a group of German gymnasium students of grade 10 about ionic bonding and how they describe the solid salt after evaporation of water from salt solution. Most of the participants drew pictures or answered with salt particles or NaCl particles . It appears to be natural to rely upon the old tried and trusted concept of particles. 

Even after teaching the traditional lesson on ionic bonding, a high school teacher came across these concepts of salt particles or NaCl particles again although the students have learned a lot about ions and ionic charges over a period of 10 lessons, they still produce concepts which are comparable to the status quo before any of these lessons were introduced. That means that this concept does not outlast the lesson. It does not mean that the students do not know the correctly intended concept taught in the lesson unit but rather that... 

These plots are called Kohler curves after their originator (Kohler, 1936). His assumptions that cloud condensation nuclei (CCN) are water-soluble materials is now widely accepted. In the past, it was often thought that NaCl particles from the ocean were the main CCN however, more recent studies have demonstrated the frequent dominance of sulfate particles with composition between H2SO4 and (NH4)2S04-... 

Ghadiri et al. (1991) used SEM to study the impact damage on NaCl particles developed from different processing routes. Local plastic deformation phenomena leading to cracks, including lateral cracks, and flaw paths are illustrated in Ghadiri et al. (1991). Yan and Barbosa-Canovas (1997)... 

FIGURE 9.15 A micrograph of a single NaCl particle with electrical mobility equivalent diameter of 550 nm. The dry NaCl is almost cubic with rounded edges. Also shown is a polystyrene latex (PSL) particle with diameter of 491 nm (Zelenyuk et al. 2006). 

Calculate the Stokes diameter of the NaCl particle of the previous example. The two approaches (dynamic shape factor combined with the volume equivalent diameter and the Stokes diameter) are different ways to describe the drag force and terminal settling velocity of a nonspherical particle. The terminal velocity of a nonspherical particle with a volume equivalent diameter Dve is given by (9.104),... 

The Stokes diameter of the NaCl particle can be calculated from (9.106) ... 

Multicomponent aerosol particles exhibit behavior similar to that of single-component salts. As the ambient RH increases the salt mixture is solid, until the ambient RH reaches the deliquescence point of the mixture, at which the aerosol absorbs atmospheric moisture and produces a saturated solution. A typical set of data of multicomponent particle deliquescence, growth, evaporation, and then crystallization is shown in Figure 10.7 fora KCl-NaCl particle. Note that the DRH for the mixed-salt particle occurs at 72.7% RH, which is lower than the DRH of either NaCI (75.3%) or KC1 (84.2%). 

Particles consisting of multiple salts exhibit a more complicated behavior (Figure 10.7). For example, the evaporation of a KCl-NaCl particle is characterized by two step changes the first at 65% with the formation of KC1 crystals and the second at 62% with the... 

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