Abstract: Disclosed are methods and apparatus for determining phase transition temperatures and, more particularly, for determining cloud, fluidity, freezing, and haze points of hydrocarbon fuels and hydrocarbon/oxygenate fuel blends. The attenuation of laser light as it passes through the sample, then through a laser line filter, and then into a photodetector is used to determine the transition temperature.

Abstract: Process for the determination of the turbidity point of a liquid, which consists in progressively cooling the liquid and noting the temperature at which turbidity appears; the temperatures at the center (T.sub.1) and at the periphery (T.sub.2) of the liquid are measured, their graphs as a function of time (.theta.) are plotted and changes in the slope of these graphs are noted, the turbidity point being the temperature (T.sub.1) at the center of the liquid which corresponds to the change in slope on the graph T.sub.2 -.function.'(.theta.).

Abstract: A can container made of soft material such as aluminum having a wall thickness of less than 0.2 mm is used for low acid foods or drinks having pH of more than 5.0. A controlled quantity of liquified nitrogen is introduced into the can filled with the low acid foods or drinks and then the can is hermetically sealed off by double-seaming. The liquid nitrogen is soon gasified in the sealed can to increase internal pressure of the can to a level sufficient to prevent the can from being deformed. Then the can is subjected to retort sterilization treatment at a predetermined high steam temperature for a predetermined period of time for sterilization of any possible bacilli and bacteria in the low acid foods or drinks in the can. Prior to retort sterilization treatment, a thermal sensitive paint is applied to the can, which will change color when exposed to a steam of a predetermined temperature for a predetermined period.

Abstract: A method and apparatus is disclosed for detecting thermal waves. This system is based on the measurement of the change in reflectivity at the sample surface which is a function of the changing surface temperature. The apparatus includes a radiation probe beam that is directed on a portion of the area which is being periodically heated. A photodetector is aligned to sense the intensity changes in the reflected radiation probe beam which results from the periodic heating. These signals are processed to detect the presence of thermal waves.

Abstract: A method and apparatus for determining the saturation temperature of a solution containing a dissolved substance, the crystals of which are optically anisotropic. The solution is placed in an optical measurement vessel under conditions wherein crystals of said substance are present, and the temperature of said crystal containing solution is gradually increased to at least the temperature at which all of the crystals dissolve. The temperature of the solution is continuously measured. Simultaneously with the temperature increase, a beam of linearly polarized light is directed into the optical measurement vessel in a manner such that it is transmitted through said solution; the transmitted beam of light, after having passed through the solution, is directed through a light polarizing analyzer having a direction of polarization normal to that of said beam of light; and at least a portion of any light transmitted through said analyzer is directed to a light measuring photodetector.

Abstract: Liquid hydrocarbon samples from a mainstream are diverted through a sample cell in cooling chamber. An optical cloud point detector signals a microprocessor-based control system which controls the charging and cooling of the cell. Cloud point reference level is continuously updated. After each measurement cycle, the control system readjusts the cooling power so that the time interval between the end of the flush cycle and cloud point detection is brought within a predetermined range. The control system switches between several distinct modes of operation automatically.

Abstract: The present invention provides a thermal imaging method to evaluate the surface and subsurface properties of a material and is based on techniques of optical beam deflection thermal imaging. The invention uses a localized excitation source, such as an optical beam, to provide localized heating of the sample surface. A surface thermal gradient is induced on the sample surface as heat flows, in three dimensions, from the area of localized excitation into the test material. The surface temperature gradient causes a thermal refractive lens to be generated in the fluid (gas or liquid) adjacent to the sample surface. An optical probe beam is directed through the thermal lens and is deflected by changes in a refractive index of the thermal lens. Changes in the refractive index are induced by variations of the surface temperature. In this manner, a detailed surface temperature profile can be generated which reveals surface and subsurface properties of the material tested.

Abstract: A method and apparatus for preparing and studying samples of materials supercooled and solidified in a containerless, low-gravity environment in bulk form is disclosed which includes an enclosure 10 in which a containerless environment is provided in which a sample specimen 52 is positioned. Method contemplates heating the specimen 52 in the containerless environment, dropping the specimen melt through the tube 12 wherein it cools by radiation, and alternately backfilling the tube 12 with an inert gas whereby the specimen melt cools by both radiation and convection during its free fall. During the free fall, the sample is in a containerless, low-gravity environment which will enhance supercooling in the sample and prevent sedimentation and thermal convection influences. The sample will continue to supercool until nucleation occurs which is detected by silicon photovoltaic detectors. The sample will solidify after nucleation and be completely solid before entering the detachable catcher.

Abstract: A method and apparatus for determining the saturation temperature of a given substance dissolved in a solution under test, based on the principle that the change in the temperature of the solution causes a specific change in the amount of light being passed through the solution. The accuracy of the determination of saturation temperature is augmented by passing a preheated air through an empty space formed between the test cell and the air seal glass thereby precluding otherwise possible formation of dew-condensation on the air seal glass. This invention is characterized by forming a thin layer of fine crystals of the substance deposited fast on the bottom face of the test cell and pouring the solution onto the thin layer in the test cell.