Nano range

Improvement in metal hydride hydrogen storage has been slow in achieving the targets needed for several applications. But slow, steady progress is foreseen as material processing in the nano-range improves the kinetics, thermodynamics, and capacity of the metal hydride systems so that they become acceptable for some applications perhaps for stationary systems. 

Figure 8.3 Size fractionation ofthe silver released from various nanotextiles and one conventional silver textile during washing. Only a small fraction of the released Ag is in the nano-range. Modified from [52].

In principle, the mechanical properties of particles can be determined by measuring their deformation under a mechanical load. This may be realised on single particles or a population. Mechanical characterisation of single particles is relatively difficult, particularly when their sizes are in the micro or nano ranges. The basis of many techniques for mechanical characterisation of single particles is micromanipulation. This can be... 

Song R., Chiang, M.Y.M., Crosby, A. J., Karim, A. and Amis, E. J., The combinatorial Measurement on the Adhesion of PMMA Thin Film in Nano Range, in preparation. 

The direction of modem device fabrication, is toward production of complex structures (including those with the elements of HTSC) with characteristic dimensions in the micro and nano ranges [426-428]. These include superlattices [429,430], and other nanocompositions [431,432], particularly those which contain HTSC/HTSC junctions (two HTSC materials with different properties), as well as HTSC/metal, HTSC/semiconductor, and HTSC/dielectric junctions. These structures form the basis of modem electronics, and exhibit different size-dependent quantum effects. 

Spray drying has been proposed as a means of providing a carrier for efficient nanoparticle delivery (Fig. 26). A nanoparticle suspension was spray dried in the presence of lactose, used as a carrier, to demonstrate that nanoparticles remained in the nano-range size after spray drying and provide a means to improve their delivery by inhalation (73). Nanoparticles made out of polystyrene, colloidal silica (20) as well as gelatin and polycyanoacrylate (73) have been spray dried in the presence of lactose DPPC or DMP to improve their drug delivery efficiency. 

As far as we know, few of nature s products are fully symmetrical, although if we could observe the nano-range of matter not currently visible to our eyes or through current technical vision aids, we may find many more. No feather, for example, is exactly the same on the left and the right side of the shaft, and none are entirely... 

Aggregation of fine particulate solids also takes place in liquids. In environmental control, the removal of particulate solids from liquid process effiuents is of great importance. As for gas/solid separations, when the size of the solids diminishes and reaches the micron or submicron (nano) range, the mass of individual particles becomes so small that they remain in suspension and carmot be removed by setding. Because of the fineness, membranes would be required to retain particles on a diaphragm, which is uneconomical for the cleaning of large volumes of contaminated liquids from industrial plants or waste-water treatment facilities. 

The common way to classify additives is by their nature and particle size. Additives can be classified as inorganic, organic, metallic, and carbon. Based on the scale of the additives particle size, they can be described as macro-, meso-, micro- and nanosized. The main interest is in nano-sized additives, in which at least one of the particle dimensions is equal to 100 nm (or 1 x 10 m) or smaller. At the same time, particle may have no dimensions (OD] in the nano-range, or one or two or three dimensions in the nano-range. 

Incorporated elastomer particles (in the micro and nano ranges) may however also be chemically cross-linked. 

To the best of our knowledge, the silicon grain particle size that allows preparation of morphologically stable composites lies within the range of 0.5-1.0 )LLm, which is about twofold higher than the typical nano -range, within which quantum confinement effects appear. 

Finally the synthesis of block copolymers containing segments of the homopolymer types mentioned above together with other functionalities will be discussed. These polymers are accessible through the living character of ROMP. The main part of this paper is dealing with rod-coil block copolymers and their phase behaviour, especially phase separation in the nano range. 

The effect of the boundary thickness is small, except in the low nano range, below 100 nm. It should also be noted that both the compressive stress and the compressive yield stress decrease in the very low nano range, indicating an inverse H-P relation. Porosity reduces the compressive yield strength, but the shape of the cmwes is not affected. 

Polymer Microspheres. For applications in drug delivery, it is desired that the polymer formulation should be present as an injectable form. From this perspective, the polymer-drug combination could be fabricated as microspheres that can be suspended in an injection vehicle prior to injection. Subcutaneous or intramuscular injections are used for microspheres whereas smaller particles (in the nano range) could be injected intravenously. Microspheres can be fabricated using a variety of techniques, some of which are described below. 

If the electrostatic field exceeds a critical limit, one or more thin solution jets emerge from the tip of the Taylor cone depending on the solution parameters and on the charge density within the droplet. The jet has a diameter of less than 100 pm, so it is not yet in the nano-range. The electric charges are carried along with the conductive jet, and due to... 

In order to obtain fibrils with diameters in the nano range, the idea is to use a more intensive melt blending technique arid obtain as fine as possible spheres of the dispersed component, applied in conjunction with high draw ratios and the smallest possible extrusion... 

By process design, the true particle size can be controlled in the submicron to nano range, thus offering dual advantage in improving the dissolution rate. 

Three potential forms of nano-particle can be distinguished, depending on how many dimensions are in the nano-range. These are regular, rod-like and platy and are illustrated in Figure 10.1. 

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