Composites sample mounting

The mounted samples were placed in the XPS vacuum chamber, and the chamber was evacuated prior to testing. The samples were exposed to the X-rays at 14.0 kV and 300 W. The approximate sampling area for the XPS is 1.0mmx3.5mm with a sampling depth of approximately 35.0 A at a 45° exit angle. Figures 16 and 17 show the survey scans from the epoxy and composite sample, respectively. Both show the presence of fluorine, which indicates the probable presence of a mold-release agent. 

Composite samples are sectioned with a diamond saw and mounted in cold curing epoxy resin. Because of their porous nature, the composites are infiltrated under vacuum and subsequently cured under pressure in order to force the mounting resin into the pores. Mounted samples are ground flat on 240 grit silicon carbide paper, finely ground with a 9 pm oil-based diamond slurry and finally polished with a 1 pm diamond slurry and a 50 nm silica suspension. 

Mechanical testing was conducted on samples 25 mm in length, 10 mm in width and 0.1 mm in thickness, Because of the high compliance of the films, it was difficult to mount an extensometer on the samples to measure E. A DMA was therefore used to assess the elastic properties of the composite samples in the tensile mode of loading. A 5 N static tensile load and displacement amplitude of 16 /tm at a frequency of 1 Hz were applied. Nine measurements for each sample were made and the average values are reported here. 

The magnitudes of the Bragg intensities used to evaluate mineral abundances are affected by inherent compositional and/or structural variations characteristic of a number of the common minerals found in coal and by non-random crystallite orientation within the sample mount. The subsequent variations in Bragg intensities cause the Bragg intensity-mineral abundance relationship to depart from linearity and result in errors of determination of mineral abundances of 10 percent or more. The procedure must therefore be considered only semiquantitative. 

Quasi-nondestmctive techniques include several transport measurements that are used to test specific membrane properties. They require sample mounting by compression sealing or glass solders that rarely leave the dehcate membrane surface intact. Gas transport properties of dense and microporous membranes are tested by measuring single gas ji as a function of and and by obtainmg fluxes and a/,from the stationary composition and flow rate of gas mixtures at the membrane feed and permeate side. To use the results of these measurements for comparison and optimized membrane designs, substantial... 

Samples of water were collected upstream of Manaus on the Rio Negro to identify DOC and determine its inorganic composition. Whole mounts of unfixed organic material (DOC) were prepared for electron microscopy by pipetting 10 OL of water sample onto Formvar and carbon-coated copper grids. After allowing the water to evaporate ofl the grids were analyzed by TEM and EDS. 

Sample Chamber and Detector. The pressure in the sample chamber is typically 10-6torr, although UHY may be required for some experiments. The samples are usually mounted on a five-axis goniometer, so that a series of samples may be loaded and analysed sequentially. The goniometer can tilt and rotate the samples relative to the direction of the incident beam. Comparing spectra obtained at different incident and exit beam angles provides fuller characterization of the sample composition as a function of depth. The samples can be electrical insulators... 

A section of the epoxy sample, approximately 2cmx2cm, was removed from the bulk and mounted onto the XPS sample stage. The sample was mounted with the "titanium" side facing down, by way of double-sided tape. Thus, the "composite side" was analyzed. The composite tube was prepared similarly and the sampling area was selected so as not to include the first 5 mm or beyond 30 mm from the end of the tube. The regions in the first 5 mm and the area beyond 30 mm from the end were classified as the non-bonded regions. Thus, the "epoxy side" or outer surface side of the composite tube was analyzed in the "bonded region". 

AFM has been used to image surfaces by probing both the attractive and repulsive forces experienced by the tip as a result of its proximity to the sample surface. In both modes, the probe tip is mounted on a cantilever spring. Three main designs have been employed metal foil with a splinter of diamond, a shaped tungsten wire that acts both as spring and tip, and microfabricated tip/cantilever composites. 

Materials and Methods. The isomeric compositions of the four polybutadienes used are listed in Table I. Samples were prepared for infrared measurement from solutions of the polymer without further purification. Most films were cast from carbon disulfide solutions on mercury or on glass plates, but a few films were cast from hexane solutions to determine whether or not the solvent affected the radiation-induced behavior. No difference was observed for films cast from the different solvents. The films were cured by exposure to x-rays in vacuum. (Doses were below the level producing detectable radiation effects.) They were then mounted on aluminum frames for infrared measurements. The thicknesses of the films were controlled for desirable absorbance ranges and varied from 0.61 X 10 s to 2 X 10 3 cm. After measuring the infrared spectrum with a Perkin-Elmer 221 infrared spectrophotometer, the mounted films were evacuated to 3 microns and sealed in glass or quartz tubes (quartz tubes only were used for reactor irradiations). 

Although as already mentioned, the information on the chemical composition of natural, low temperature chlorites in sedimentary rocks is limited some new data has been gathered using microprobe analysis of grain mounts or rock thin sections. The samples studied come from rather different geographic areas—western Montana, Algeria and the Franco-Italian Alps and African off-shore Atlantic coast shelf sediments. 

Before the blowpipe on charcoal it melts in a strong heat, turns white. on the surface, and deposits a fixed sublimate of binoxide of tin round the assay. After roasting, it affords, with the usual fluxes, the peculiar reactions of iron and copper, and a brittle globnleof the latter metal on fluxing, with soda and borax. Nitric acid decomposes it, dissolving the iron and copper, and leaving a deposit of sulphur and of bin-oxide of tin. The following analyses indicate the composition of a few samples of this ore samples A and b from Hucl Bock . 0 from St. Michael s Mount, and d from Zinnwald —... 

Recently, Mounts et al. studied the effect of genetic modification on the content and composition of tocopherols, sterols, and phospholipids in soybean oil (28). Although, in general, there was little impact on the phospholipid classes, a higher PA content was found in some crude oil samples. Compositional variations in molecular species indicated that genetic modification of soybeans affected the phospholipids at the molecular level. 

While we have not yet carried out detailed kinetic measurements on the rate of photocorrosion, our impression is that the process is relatively insensitive to the specific composition of the strontium titanate. Trace element compositions, obtained by spark-source mass spectrometry, are presented in Table I for the four boules of n-SrTi03 from which electrodes have been cut. Photocorrosion has been observed in samples from all four boules. In all cases, the electrodes were cut to a thickness of 1-2 mm using a diamond saw, reduced under H2 at 800-1000 C for up to 16 hours, polished with a diamond paste cloth, and etched with either hot concentrated nitric acid or hot aqua regia. Ohmic contacts were then made with gallium-indium eutectic alloy, and a wire was attached using electrically conductive silver epoxy prior to mounting the electrode on a Pyrex support tube with either epoxy cement or heat-shrinkable Teflon tubing. 

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