Appearance and physical properties

The masses of the smaller asteroids encountered by spacecraft have been estimated from their gravitational effects on the trajectories of passing spacecraft. The generally low 

Composite view of asteroids visited by the Galileo and NEAR Shoemaker spacecraft, as well as the asteroid-sized moons of Mars. All are shown approximately at the same scale. Clockwise from upper left are Phobos, Eros, Ida, tiny Dactyl, Mathilde (the largest object), and Deimos, with Gaspra in the center of the figure. After Sullivan et al. (2002), with permission. 

Image of asteroid Itokawa, taken by the Hayabusa spacecraft. The dumbbell shape and abundant boulders suggest this asteroid is a rubble pile, an idea supported by the asteroid s bulk density of -1.95 g cm 3. Image courtesy of JAXA. 

Some asteroids are marked by grooves, and all are pockmarked by impact craters of varying sizes. One crater on Mathilde (Fig. 11.1) is so large that it is difficult to envision how the asteroid survived the impact. The surfaces of all these bodies are covered by fine-grained regoliths and by boulders of various sizes. 

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There are several different processes and polymers used ia the manufacture of geotextiles which affect their appearance and physical properties. Geotextiles are produced ia various weights and thicknesses, which also determine their physical properties and ultimately the performance of the material when iastaHed on a project (see also high performance fibers). 

The most superficial layer of skin is the stratum comeum (SC), which consists of terminally differentiated keratinocytes (comeocytes) that originate from actively proliferating keratinocytes in lower epidermis (basale, spinosum, and granulosum cells), and contain a lamellar lipid layer secreted from lamellar bodies (Fig. 7a). Flydration of the SC is an important determinant of skin appearance and physical properties, and depends on a number of factors including the external humidity, and its structure, lipid/protein composition, barrier properties, and concentration of water-retaining osmolytes (natural moisturizing factors, NMFs) including free amino acids, ions, and other small solutes. 

Failure to meet specifications for appearance and physical properties (e.g., color, phase separation, resuspendablity, delivery per actuation, caking, hardness, and as appropriate to the product type)... 

What can we leaxn about the internal arrangement of atoms, ions, or molecules from the appearance and physical properties of a crystal The macroscopic physical properties of crystals are related to the arrangements of atoms within them. A careful examination of these physical properties leads to much useful information on the symmetry of the atomic arrangement, on the shape of the unit cell, and on the overall arrangement of molecules within the unit cell. Selected examples of such studies are described in this Chapter. 

Coal Is nearly pure carbon. It Is mined, often from strip mines, and burned as a fuel. Natural gas and oil are also carbon-rich fuels. Even though their appearance and physical properties are different, graphite and diamond are both naturally occurring forms of carbon. 

NMR spectroscopy is of special value in differentiating tetracycline antibiotics, since the functionality array common to each member (see (7))so dominates their appearance and physical properties that electronic and vibrational spectra within the group are similar and of little value for identification purposes [79]. Reviews of the H- and C-NMR spectroscopy of tetracycline antibiotics are available [75, 80] these include characteristic features of... 

Zinc salt, C, I IwC4Zn. zinc undecylenate. Amorphous white powder, mp 115-116°. Resembles zinc stearate in appearance and physical properties. Can be prepd by dissolving zinc oxide in dil undecylenic acid and concentrating the solution. 

The appearance and physical properties of fresh and archaeological woods depend in large part on the chemical composition of the material. In turn, the chemistry of wood is intimately related to its structure. Although all woods comprise primarily polysaccharides and lignins, the types and... 

The dispersion of the filler particles is also important to final sealant appearance. With increasing costs of fillers, it is also important to optimize dispersion to maximize the rheological and reinforcement benefits provided by the fillers. Manufacturers must balance the mixing time and energy required for complete dispersion with resultant product appearance and physical properties. 

In their appearance and physical properties and in most of their chemical behaviors, aluminum, gallium, indium, and thallium are metallic. Some properties of the group 13 metals are listed in Table 21.6. 

These systems can utilize an ever increasing array of target, or source metals such Chromium, Nickel, Stainless steel, and a range of alloys to provide differing appearances and physical properties. 

New PVD equipment makes it possible to precisely regulate deposition rates and residual gas pressures t control this process, and even permit multi-layer metal to change appearance and physical properties as needed. 

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