Contacting studies

The above measurements all rely on force and displacement data to evaluate adhesion and mechanical properties. As mentioned in the introduction, a very useful piece of information to have about a nanoscale contact would be its area (or radius). Since the scale of the contacts is below the optical limit, the techniques available are somewhat limited. Electrical resistance has been used in early contact studies on clean metal surfaces [62], but is limited to conducting interfaces. Recently, Enachescu et al. [63] used conductance measurements to examine adhesion in an ideally hard contact (diamond vs. tungsten carbide). In the limit of contact size below the electronic mean free path, but above that of quantized conductance, the contact area scales linearly with contact conductance. They used these measurements to demonstrate that friction was proportional to contact area, and the area vs. load data were best-fit to a DMT model. 

Testing and demonstration of concept feasibility of the UNEX process has been completed on batch contact studies using simulated and genuine sodium-bearing acidic waste stored in underground stainless steel tanks at the INL. DFs of 99.7% for Sr, > 95% for Cs, and 99.99% for actinides were achieved with a solvent composed of CCD, PEG, and Ph2-CMPO, dissolved in either a light or a heavy non-nitroaromatic diluent (respectively less or more dense than the aqueous feed). 

Another application of ICP-MS in the area of food safety is the evaluation of food contact materials. Q [86] and TOF [87] mass spectrometers have been employed in the compositional analysis of paper and board material intended for food contact. Studies on the migration of metals from food contact plastics using food simulants and ICP-MS detection have also been reported. One of them showed how to analyze different simulants without the need of any time-consuming preparation, that is, aqueous acetic acid (3 percent w/v) directly, aqueous ethanol (15 percent v/v) after proper dilution, the olive oil simulant following emulsion preparation by means of tetralin and Triton X-100 [88]. 

Moore, C. J. Heat Transfer across Surfaces in Contact Studies of Transients in One-dimensional Composite Systems, Southern Methodist Univ., Thermal Fluid Sci. Ctr. Res. Rep. 67-2, Dallas, Tex., March 1967. 

No studies were found that examined elimination in humans or experimental animals exposed to hydrogen cyanide by inhalation or dermal contact. Studies in rats exposed to cyanide orally or by subcutaneous injection showed that cyanide is excreted primarily as thiocyanate in the urine but also is exhaled as a gas and excreted in feces (Ansell and Lewis 1970 Leuschner et al. 1991 Okoh 1983). 

In particular, contacting studies where two phases of varied constituents (surfactant, cosurfactant, oil, water, electrolyte) are in contact and results interpreted on the basis of mass transfer and phase diagrams have become the standard method for studying transport in such systems (10-18). 

Batch contact studies have shown that both Am(III) and Pu(IV) transfer rapidly at 23 to 25°C between DHDECMP-diluent solutions and aqueous HNO3. In all tests conducted, equilibrium was reached in <30 seconds. 

Figure 6.4 Schematic diagram of lap shear in acid/monomer area contact study. The total contact area for each lap shear was determined by the total sum (A,B,C,D and E) of all areas of the lapshear...

Stability of K- LaiOs catalysts during the combustion of Diesel soot. High Frequency CO2 Pulses and soot - catalyst contacting studies... 

Miyanaga Y., Fukubayashi T., and Kurosawa H. 1984. Contact study of the hip joint load deformation pattern, contact area, and contact pressure. Arch. Orth. Trauma Surg. 103 13-17. 

Stormont T.J., An K.A., Morrey B.E et al. 1985. Elbow joint contact study comparison of techniques. 

The hazards associated with skin contact of bitumens other than burns are negligible. Flowever, cut-back bitumens and bituminous emulsions, because they are handled at lower temperatures, increase the chance of skin contact. Studies carried out by Shell demonstrated that the bitumen is unlikely to penetrate the skin and the bitumens diluted with solvents are unlikely to present a carcinogenic risk. Nevertheless, bituminous emulsions can cause irritation to the skin and eyes and can produce allergic responses in some individuals (Shell Bitumen 2003). 

The future development of porous silicon (PS)-based optoelectronic devices depends on a proper understanding of electrical transport properties of the PS material. Electrical transport in PS is influenced not only by each step of processing and fabrication methods but also by the properties of the initial base substrate. This chapter endeavors to chronologically document how the knowledge base on the nature of carrier transport in PS and the factors governing the electrical properties has evolved over the past years. The topics covered include the proposed electrical transport models including those based on effective medium theories, studies on contacts, studies on physical factors influencing electrical transport, anisotropy in electrical transport, and attempts to classify the PS material. 

The health effects of methyl chloroform are well characterized after many years of industrial use. The primary effects of acute overexposure to the chemical are to the central nervous system (e.g., light-headedness, drowsiness, headache). Lethal effects of excessive concentrations (at 10,000 ppm) of the chemical have been reported after accidental exposure or abuse. In these cases, death resulted from respiratory and cardiac failure caused by depression of the central nervous system. Cardiac sensitization also may have contributed. Prolonged exposure (15 minutes or more) to high concentrations (1000 to 2000 ppm) of the solvent in the air results in mild irritation of the eyes and respiratory tract. In its liquid form, methyl chloroform causes irritation to the skin and eyes upon contact. Studies of workers occupationally exposed to methyl chloroform for up to 6 years have demonstrated no adverse health effects. Animal studies of chronic exposure to the chemical at levels ranging up to 1750 ppm similarly have found no adverse health effects. 

Subsequent experimentation by contact studies with other chiral systems (/ )- and (S)-, of differing parity revealed the following helical twist sense relationships, entries 1 to 4 in Table 1. These results form the basis of a set of empirical rules termed the Gray and McDonnell rules [32] and are particularly useful in predicting the properties of a chiral nematic phase of a given com-... 

Pisarello, M. L., Saux, C., Miro, E. E. Querini, C. A. (2001). Stability of K-La203 catalysts during the combustion of Diesel soot. High frequency CO2 pulses and soot-catalyst contacting studies. Stud. Surf. Set. Catal, 139,141-148. 

---