Environmental scanning electron microscopy of marine aggregates

Marine aggregates were examined for the first time in the hydrated state using an environmental scanning electron microscope (ESEM). Sample preparation consisted of fixation followed by rinsing with distilled water to remove excess salts and fixative. Aggregates were continuously observed at resolutions comparable to conventional scanning electron microscopy through stages of hydration, from completely immersed to desiccated. Because no metallic coating is required, energy-dispersive X-ray spectroscopy (EDXS) can be used to analyse rapidly constituent elements occurring at low concentrations with no spectral interference. Subtle differences in mineral particles were seen in both EDXS spectra and in direct observation of relative hydration, reflecting apparent differences in mineralogy. ESEM enabled examination of effects of desiccation and rehydration on individual particles composed primarily of hydrated polymer and eliminated dehydration artefacts in delicate organisms.     

Effects of self heating when using a continuous bridge voltage for strain gauging epoxy models

One source of concern when strain gauging epoxy materials, is that if the gauges are continuously energised at high power densities, then the heat generated by the strain gauges will cause large apparent strains and will reduce the modulus of the underlying material. The magnitude and significance of the heating effect are discussed and methods of reducing this effect are indicated.     

ANALYSIS OF COFFEE, TEA AND ARTIFICIALLY FLAVORED DRINKS PREPARED FROM MINERALIZED WATERS

ABSTRACT— Coffee, black tea and artificially flavored and artificially sweetened orange and grape soft drinks were prepared from solutions of 8 minerals each at 750 ppm. Additionally, coffee and tea were brewed, using 6 natural drinking waters which ranged from 42–1,725 ppm of total dissolved solids. Beverages made from solutions containing carbonates were the least desirable, having flat, insipid characteristics. Although distilled water resulted in an acceptable soft drink, coffee and tea prepared from it were excessively sour and astringent, respectively. The recommended formula of 53.3 g of coffee per liter of water was considered too strong and "burnt' for the panel of trained judges, so that the experiments were repeated at a lower concentration of 47 g coffee/liter water. Large differences in the direction and magnitude of the visual characteristics of the coffee and tea brewed from the various waters also were observed in the marked changes in luminous transreflectance, purity and shifts in dominant wavelengths measured by thin-layer reflectometry.