Unique particles

It has also been reported that the tableting characteristics of instant sorbitol result from its unique particle morphology [28]. Disintegration of instant sorbitol model tablets was found to be slower than tablets prepared using lactose, but this parameter can be optimized by proper disintegrant selection. 

Soils can have characteristics due to human activity (anthropogenic soils). The forensic examination of soil is therefore not only concerned with the analysis of naturally occurring rocks, minerals, plant, and animal matter it also includes the detection of such manufactured materials as ions from synthetic fertilizers and from different environments (e.g., nitrate, phosphate, sulfate) and environmental artifacts (e.g., lead or objects such as glass, paint chips, asphalt, brick fragments, and cinders). Each of these materials can represent distinct soil characteristics. When unique particles are found in soil evidence, more precise and rapid discrimination can be achieved even if the amount of evidence recovered is microscopic (Sugita and Marumo 2004). For this reason, microscopy is often considered the most useful technique for the detection of such characteristic particles. 

Sugita, R. and Marumo, Y. (2004). Unique particles in soil evidence, in Forensic Geoscience Principles, Techniques and Applications (K. Pye and D. J. Croft, Eds.). London Geological Society Special Publication 232, 97-102. 

The ratio of indicative to unique particles is markedly different from that of firearm discharge. From firearm residue casework statistics, based on cases with at least one particle in the unique category, the ratio of indicative to unique particles is approximately 35 1. For starting pistol discharge residue particles the overall ratio is in the region of 1 10. 

As can be seen from Table 19.3, the proportion of indicative particles exceeds the proportion of unique particles, even for promptly collected FDR. The higher proportion of indicative particles detected in casework is almost certainly due to particles from nonfirearm sources, particularly single primary element ones, meeting the criteria of the classification scheme. 

From casework statistics the unique particles (those containing the combination lead, antimony and barium, and those containing antimony and barium) occur in the ratio 7 3, respectively. Approximate percentages for indicative particles are lead-only 55% lead, antimony 20% lead, barium 8% antimony-only 7% barium, calcium, silicon 5% barium-only 5%. Table 19.3 gives an indication of the levels of the primary elements in each particle type. Table 19.4 gives an indication of the levels of accompanying elements in each particle type and is the basis for note b in Table 19.5, Particle Classification Scheme. 

Future work on these unique particles, which may act as prototypic structures for investigations of semiconductor boundaries, inner surfaces, and charge carrier separation and localization, will include the systematic study of temperature-dependent charge carrier dynamics as a function of the composition of the particles as well as experiments with materials other than CdS and HgS. It is believed that the preparative approach should be of more generality, possibly yielding particles consisting of more than one well and/or more than two materials. 

How many different unique particle tracks would you expect to find in cyclotron boards of the size in this chapter ... 

The most popular effective medium theories are the Maxwell Garnett theory [18], which was derived from the classical scattering theory, and the Bruggeman theory [19]. With these theories, an effective dielectric function is calculated from the dielectric functions of both basic materials by using the volume filling factor. At some extensions of these theories, a unique particle shape for all particles is assumed. There is also an other concept based on borders for the effective dielectric functions. The borders are valid for a special nanostructure. Between these borders, the effective dielectric function varies depending on the nanostructure of the material. The Bergman theory includes a spectral density function g(x) that is used as fit function and correlates with the nanostructure of the material [20]. 

Most nanoparticle uptake and translocation research has quantified nanoparticles in vivo using some type of unique particle label. For example, nanoparticle laboratory studies have included radioactive particles [4], trace metals such as gold and iridium [7], and fluorescent particles [8]. However, the population exposures most relevant to health involve the emissions or deliberate release of high-production-volume manufactured nanomaterials and exposures to incidental nanoparticles, such as soot. Combustion emissions and manufactured powders such as fumed silica, ultraflne titanium dioxide (Ti02), and similar industrial materials rarely have a unique and easily detected label. 

Particles nucleated from supercritical fluids have unique particle size, shape, and particle size distributions. The means of achieving nu-cleation and growth are many, and include pressure reduction, temperature perturbation, and addition of anti-solvents. Time profiling and staging have profound effect on the particle characteristics. The effeet of pressure reduction on the resulting nucleated material for different solute concentrations is illustrated in Figure 21.1.14. 

Today s standard vacuum evaporators are far removed from open pans. The so-called grainer process actually is closer to the original vacuum-pan process [17,18]. It was displaced by developments in the vacuum-pan process. It survives as a minor source thanks largely to the unique particle characteristics of its product. These are due to slow rates of evaporation from large, quiescent brine surface areas. A flow of air across the brine surface keeps the evaporation temperature at 90-95°C. Surface tension keeps afloat the flakes that initially form. Growth continues, mostly on the underside, until the hollow, pyramidal particles reach a size where they sink to the bottom. The process obviously is energy-intensive, and this fact accounts for its commercial demise [2]. 

The sol-gel technique has been used to prepare sub-micrometer metal oxide powders [5] with a narrow particle size distribution and unique particle shapes (e.g. AljOj, TiOj, ZrOj, Fe Oj). Uniform SiO spheres have been grown from aqueous solutions of colloidal SiO [6]. Metal-ceramic composites (e.g. Ni-Al Oj, Pt-ZrO ) can also be prepared in this manner [7]. Organic-inorganic composites have been prepared by the sot-gel route. By employing several variants of the basic sol-gel technique, a number of multicomponent oxide systems have been prepared. Some typical examples are SiO -B Oj, SiO -TiO, SiO -ZrO, SiO -Al Oj and ThO -UO. A variety of ternary and still more complex oxides such as PbTiOj, PbTij r 3 and NASICON have been prepared by this technique [1-3, 8]. 

A unique particle physics framework has been proposed, which can account for the energy density fluctuations with the characteristics found in CMBR. One conjectures that the large-scale homogeneity of the Universe is due to a very early period of exponential inflation in its scale (Peebles 1993). 

If a piece of metal is reduced to a size of a few thousand atoms we enter the world of metal colloids, unique particles which were already handled by Michael Faraday in the last century. Smaller units of a few hundred or dozen atoms are usually called clusters . This term is also well tried for small molecular species consisting of only a few metal atoms. Metals, especially transition metals, offer an exceptional opportunity to study the pathway which leads from the bulk to the molecular state and finally to mononuclear complexes (Figure 1-2). 

Figure 1 depicts the SEM of cloud substance from guava juice under various processing conditions. The cloud surface of the fresh sample (unheated and not pressurized) was irregular and with unique particle size (Fig. 1, A B). The particle distribution and appearance of pressurized juice (6,000 atm, 25 °C, 15 min) were similar to the fresh sample (Fig. 1, C D). Takahashi et al (1993) have reported that the soluble solid particle distribution in citrus juice does not change after high pressure treatment. However, the cloud surface of pasteurized juice was observed to be greatly different from the pressurized juice (Fig. 1, E F) due to coagulation of the small particles.

When Thomson identified the electron, he found that the ratio of its charge to its mass (the e/m ratio) was the same regardless of the element from which the electron came. This showed that the electron is a unique particle that is found in atoms of aU elements. Positively charged particles found at about the same time did not all have the same e/m ratio. (Later it was found that even different atoms of the same element contain positive particles that have different e/m ratios.) What does that suggest about the mass, particle charge, and minimum number of positive particles from different elements ... 

A pigaent with unique particle size distribution. Its easy dispersion characteristics have denonstrated its unusual merit as a mix-in type of pigment for a wide variety of applications such as carpet backing, roof compounds, spackles, and coatings. Particle Size Range (micrometers) Up to 44 Mean Particle Size (micrometers) 11.0 Oil Absorption (rub-out) 7-9... 

An ultrafine ground coated pigment with a unique particle size distribution. The clean top size and lack of ultrafine should permit higher loadings in polymer systems while still maintaining properties. 

---