Abstract: A dental porcelain material free of yellow coloring or opacification upon firing is produced. A powder mixture is prepared by adding 0.1 to 2.0 wt % of antimony trioxide and 0.01 to 5 wt % of nitric acid or its salt or salt, to a porcelain starting material. The powder mixture is heat-treated at a temperature not lower than the softening temperature of the powder mixture to produce a fused mass which is pulverized and water-washed. 0.01 to 5 wt % of nitric acid or its salt or salts may be added again during the pulverizing step.

Abstract: A sensor system for determining the pH or carbon dioxide concentration of a liquid medium comprising, in combination, a pH-insensitive fluorescent indicator and a PH-sensitive fluorescent indicator which act in concert or a single fluorescence indicator which emits fluorescent signals of different wavelengths in different carriers, which system(s) produce diverging signals, the ratio of which provides an accurate and stable determination of the parameter being measured. A method for determining pH and CO.sub.2 concentration is also disclosed.

Abstract: A device for transmitting electromagnetic radiation to a radiation sensitive component and receiving output radiation from said component comprising a radiation-transmissible junction formed by contacting the tip of a first optical fiber with an intermediate portion of a second optical fiber, said junction being encased in an opaque, radiation reflective jacket. A method for determining a desired parameter using such device is also disclosed.

Abstract: A method of measuring the concentration of carbon dioxide in a medium by determining the water content in a pH-independent sensor system comprising an optical fiber having attached thereto a fluorescence indicator embedded in a carrier matrix containing a miscible mixture of water and non-aqueous solvent in predetermined proportions and being separated from said medium by a gas-permeable, water-impermeable diffusion membrane, said indicator, when excited by excitation radiation of a predetermined wavelength, emitting fluorescent emission whose intensity is dependent upon the ratio of water to non-aqueous solvent present in the system such that the ratio of intensities of emitted radiation is therefore proportional to the amount of water present and diffusion of carbon dioxide through said gas-permeable membrane and subsequent reaction with water to deplete the water content of the system induces a change in the intensities of said emissions, which method comprises transmitting excitation radiation through sai

Abstract: A multi-channel electromagnetic radiation transmission system comprising a plurality of first cladded optical fibers coupled to at least one second cladded optical fiber through a series of radiation-transmissible junctions each of which is encased in an opaque, radiation reflective jacket, and including means for attachment to radiation sensitive components whose emission signals are adapted to be received without substantial attenuation by a radiation measuring, transducing, recording or retransmitting component. A method for determining a plurality of parameters using such a system is also disclosed.