Micron composite

Liversidge and Cundy reported a dramatic increase in the oral bioavailabiUty of a nanoparticulate danazol composition relative to a micronized composition when administered to fasted beagle dogs. Danazol, sold under the ttadename Danocrine , is a synthetic steroid used to tfeat endometriosis. It has an aqueous solubility of approximately lOpg/mL and has the chemical sttucture shown in Fig. 3. 

While increased sensitivity can make nano-thermites more dangerous to handle, the increased friction or impact sensitivity is also beneficial in some practical applications such as percussion primers. However some nano-thermites have increased ESD sensitivity, which has no current practical apphcation and is only a safety hazard. For example, a Bi203/Al nano-thermite has sufficient impact and friction sensitivity to be considered for use in ammunition primers, however it has an ESD sensitivity of 0.125 gj (40 nm Bi203, 41 nm Al). This is a static potential, which is easily achieved by the human body. This makes handling hazardous, especially since the Bi203/Al thermite has a combustion velocity of over 750 m/s which means that this thermite explodes rather than bums. The increased ESD sensitivity of nano vs. micron composites is believed to be the result of the increased ability of high surface areas to develop charges. 

The X-ray microanalysis is the basic method of study of rare-metal and rare-earth minerals of micron size. The multi-component composition, instability of minerals under the electron beam, overlap of X-ray characteristic lines, absence of reference samples of adequate composition present difficulties in the research of mineral composition. 

The elemental composition of the fish otoliths is a potential source of the useful information to recreate environment history of the individual fish in some of the species. In-depth study of the chemical composition of the otolith center (formed eaidy in fish life) and otolith edge (formed later in fish life) ensures chronological and environmental information stored in the otoliths [1]. This infoiTnation may be achieved by X-ray electron probe microanalysis (EPMA). EPMA is the analytical method to determine the elemental composition of different otolith s parts, their sizes varying from ten up to some tens of microns. 

Electron Probe Microanalysis, EPMA, as performed in an electron microprobe combines EDS and WDX to give quantitative compositional analysis in the reflection mode from solid surfaces together with the morphological imaging of SEM. The spatial resolution is restricted by the interaction volume below the surface, varying from about 0.2 pm to 5 pm. Flat samples are needed for the best quantitative accuracy. Compositional mapping over a 100 x 100 micron area can be done in 15 minutes for major components Z> 11), several hours for minor components, and about 10 hours for trace elements. 

Quantifying the effect of surface roughness or morphology is difficult, however. Surface preparations that provide different degrees of surface roughness also usually produce surfaces that have different oxide thicknesses and mechanical properties, different compositions, or different contaminant levels. The problem of separation of these variables was circumvented in a recent study [52] by using a modified microtome as a micro milling machine to produce repeatable, well-characterized micron-sized patterns on clad 2024-T3 aluminum adherends. Fig. 2 shows the sawtooth profile created by this process. 

Airborne particulate matter, which includes dust, dirt, soot, smoke, and liquid droplets emitted into the air, is small enough to be suspended in the atmosphere. Airborne particulate matter may be a complex mixture of organic and inorganic substances. They can be characterized by their physical attributes, which influence their transport and deposition, and their chemical composition, which influences their effect on health. The physical attributes of airborne particulates include mass concentration and size distribution. Ambient levels of mass concentration are measured in micrograms per cubic meter (mg/m ) size attributes are usually measured in aerodynamic diameter. Particulate matter (PM) exceeding 2.5 microns (/i) in aerodynamic diameter is generally defined as coarse particles, while particles smaller than 2.5 mm (PMj,) are called fine particles. 

The synthesis effort was initiated by the Horie group on mechanically blended powder mixtures of 3 parts nickel with 1 part aluminum in molar proportions and a similar sample composed of a composite particle of nickel plated on aluminum in similar proportions. The powders were a 44 74 m nickel powder and a 5-15- m micron aluminum powder, a coarse fine mixture. The powder mixtures were shock loaded to peak pressures of 7.5 and 22 GPa with starting powder densities of 60% of solid density. 

PS/PHEM A particles in micron-size range were also obtained by applying the single-stage soapless emulsion copolymerization method [124]. But, this method provided copolymer particles with an anomalous shape with an uneven surface. PS or PHEMA particles prepared by emulsifier-free emulsion polymerization were also used as seed particles with the respective comonomer to achieve uniform PS/PHEMA or PHEMA/PS composite particles. PS/PHEMA and PHEMA/PS particles in the form of excellent spheres were successfully produced 1 iLitm in size in the same study. 

The first method used for wear particle analysis is routine monitoring and trending of the solids content of machine lubricant. In simple terms the quantity, composition and size of particulate matter in the lubricating oil is indicative of the mechanical condition of the machine. A normal machine will contain low levels of solids with a size less than 10 microns. As the machine s condition degrades, the number and size of particulate matter will increase. 

The reliability of the results depends in large measure on how well deviations from the (ideal) linear relationship between log / and dry weight per unit area can be eliminated or allowed for. As is well known, this can be accomplished by the comparative method (3.10), provided that standard (reference system) and unknown, identical in mass, shape, and elementary composition, are exposed to the same x-ray beam. In the cytological investigations, these conditions are difficult to meet, not only because the samples are complex in composition, but also because they are very small, as is clear from the units employed (micromicrograms per square micron or 10 12 gram per 10 8 sq cm). 

Baldwin (Ref 65) also synthesized a copolymer from acrylic acid and carboranylmethyl acrylate which was used to make the proplnts in Table 36. Composition A has the burning rates shown in the table for the AP particle sizes indicated. Composition B had an average AP particle size of 15 microns and a burning... 

Ternary Nitrides as Diffusion Barriers. Barrier layers with good step coverage and low resistivity are formed from ternary nitrides with various compositions Ti-Si-N, W-Si-N, and W-B-N. They are deposited by MOCVD with deposition temperatures between 300 and 450°C. Complete step coverage is obtained on reentrant features as low as 0.25 micron with an aspect ratio of 4.0.Pi]... 

The Vinyloop process is based on the selective dissolution of PVC used in composites applications like cable insulation, flooring, tarpaulins, blisters, etc. After removal of insoluble parts like metals, rubber or other polymers, the PVC is reprecipitated with all additives by introduction of a non-solvent component whieh will form with the seleetive solvent an azeotropie mixture. By using typical conditions, the process is able to reeover a pure PVC eompound powder ready for use without any additional treatment like melt filtration or a new pelletisation (speeific characteristics of the powder are average diameter of 400 microns and bulk density above 600 kg/ eub.m). All the solvents used are eompletely reeyeled and reused. PVC compounds recovered in the Vinyloop process can be reused in a closed-loop recycling scheme... 

Morphology of the enzymatically synthesized phenolic polymers was controlled under the selected reaction conditions. Monodisperse polymer particles in the sub-micron range were produced by HRP-catalyzed dispersion polymerization of phenol in 1,4-dioxane-phosphate buffer (3 2 v/v) using poly(vinyl methyl ether) as stabihzer. °° ° The particle size could be controlled by the stabilizer concentration and solvent composition. Thermal treatment of these particles afforded uniform carbon particles. The particles could be obtained from various phenol monomers such as m-cresol and p-phenylphenol. 

Catalytic activity tests have been performed in a quartz microreactor (I.D.=0.8 cm) filled with 0.45 g of fine catalyst powders (dp=0 1 micron). The reactor has been fed with lean fiiel/air mixtures (1.3% of CO, 1.3% of H2 and 1% of CH4 in air resp ively) and has been operated at atmospheric pressure and with GHSV= 54000 Ncc/gcath The inlet and outlet gas compositions were determined by on-line Gas Chromatography. A 4 m column (I D. =5mm) filled with Porapak QS was used to separate CH4, CO2 and H2O with He as carrier gas. Two molecular sieves (5 A) columns (I D.=5 mm) 3m length, with He and Ar as carrier gases, were used for the separation and analysis of CO, N2, O2, CH4, and H2, N2, O2 respectively... 

Ion Beam Analysis (IBA) utilizes high-energy ion beams to probe the elemental composition of the surface of a specimen in a non-destructive way. It can establish the composition as a function of depth to several microns, with a typical depth resolution of 10-20 nm. It is a fast and standardless technique which quantifies the absolute atomic ratios, and can also determine the film thickness. 

Fig. 22 Dissolution fates of various griseofulvin and gri-seofulvin-succinic acid samples as determined by the oscillating bottle method. , griseofulvin, crystalline A, griseofulvin, micronized , eutectic mixture 0> physical mixture at eutectic composition , solid solution A, physical mixture at solid solution composition. The dashed line indicates the equilibrium solubility of griseofulvin in water. (From Ref. 41.).

FIGURE 23 Hydration layer in obsidian. When obsidian is broken into two or more pieces, new surfaces are created. As a new surface is exposed to the environment, water (from atmospheric humidity, rain, or the ground) penetrates the surface gradually, the water diffuses into the bulk and forms hydrated obsidian, that is, obsidian containing water. With time, the thickness of the hydration layer, as such a layer is known, gradually increases the rate of increase is affected by such factors as the vapor pressure of the water in the atmosphere, the environmental temperature, and the composition of the surrounding environment as well as of the obsidian. If the hydration layer reaches a thickness of 0.5 microns or more, it becomes discernible under a microscope, the thickness can be measured, and the age of the surface calculated. The microphotograph shows an hydration layer on obsidian. 

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