Abstract: Methods and apparatus provide for: producing a plasma plume within a plasma containment vessel from a source of plasma gas; feeding an elongate feedstock material having a longitudinal axis into the plasma containment vessel such that at least a distal end of the feedstock material is heated within the plasma plume; and spinning the feedstock material about the longitudinal axis as the distal end of the feedstock material advances into the plasma plume, where the feedstock material is a mixture of compounds that have been mixed, formed into the elongate shape, and at least partially sintered.

Abstract: Methods and apparatus provide for: feeding glass batch material into a plasma containment vessel; directing one or more sources of plasma gas into an inner volume of the plasma containment vessel in such a way that the plasma gas swirls in a cyclonic fashion within the plasma containment vessel; and applying first and second electromagnetic fields to the plasma gas to facilitate production of a plasma plume within the inner volume of the plasma containment vessel, where the plasma plume is of a generally cylindrical configuration, and is of sufficient thermal energy to cause the glass batch material to thermally react.

Abstract: An ultrasonic transducer assembly includes an ultrasonic transducer, an ultrasonic booster, an ultrasonic probe, and a booster cooling unit. The ultrasonic booster is connected to the ultrasonic transducer to amplify acoustic energy generated by the ultrasonic transducer and transfer the amplified acoustic energy to the ultrasonic probe. A seated end of the ultrasonic probe is positioned in a probe seat of the ultrasonic booster. The booster cooling unit is positioned to regulate the temperature of the probe seat of the ultrasonic booster such that the assembly supports a temperature dependent press-fit engagement of the seated end of the ultrasonic probe and the probe seat of the ultrasonic booster. The temperature dependent press-fit engagement is such that the seated end of the ultrasonic probe can be reversibly moved in and out of the probe seat at an elevated temperature THOT and is fixed in the probe seat at room temperature TCOLD.

Abstract: Methods and apparatuses for forming optical preforms from silica glass soot are disclosed. According to one embodiment, a method for forming an optical preform may include loading silica glass soot in a mold cavity of a mold body. The mold body may be rotated at a rotational speed sufficient to force the silica glass soot towards an inner wall of the mold body. Thereafter the silica glass soot is compressed in an inward radial direction as the mold body is rotated to form a soot compact layer.

Abstract: A method of applying ultrasonic acoustic energy to a glass melt by monitoring a glass melt temperature TY and transferring ultrasonic acoustic energy from an ultrasonic transducer to the glass melt at a controller power PC and a controller frequency vC through an ultrasonic probe positioned in the glass melt is provided. According to the method, the controller power PC is controlled in response to at least (i) the monitored glass melt temperature TY and (ii) a reference glass melt temperature TR. The controller frequency vC is controlled in response to at least (i) one or more input parameters from a temperature-viscosity curve characterizing the glass melt, (ii) one or more input parameters from one or more temperature dependent impedance response models of the glass melt, and (iii) ?Z, where ?Z represents a degree to which an impedance condition ZY of the ultrasonic probe differs from a reference impedance ZR when the ultrasonic probe is positioned in the glass melt.

Abstract: An ultrasonic transducer assembly is provided comprising an ultrasonic transducer, an ultrasonic booster, an ultrasonic probe, and a booster cooling unit. The ultrasonic booster is connected to the ultrasonic transducer to amplify acoustic energy generated by the ultrasonic transducer and transfer the amplified acoustic energy to the ultrasonic probe. A seated end of the ultrasonic probe is positioned in a probe seat of the ultrasonic booster. The booster cooling unit is positioned to regulate the temperature of the probe seat of the ultrasonic booster such that the assembly supports a temperature dependent press-fit engagement of the seated end of the ultrasonic probe and the probe seat of the ultrasonic booster. The temperature dependent press-fit engagement is such that the seated end of the ultrasonic probe can be reversibly moved in and out of the probe seat at an elevated temperature THOT and is fixed in the probe seat at room temperature TCOLD.

Abstract: A method of applying ultrasonic acoustic energy to a glass melt by monitoring a glass melt temperature TY and transferring ultrasonic acoustic energy from an ultrasonic transducer to the glass melt at a controller power PC and a controller frequency vC through an ultrasonic probe positioned in the glass melt is provided. According to the method, the controller power PC is controlled in response to at least (i) the monitored glass melt temperature TY and (ii) a reference glass melt temperature TR. The controller frequency vC is controlled in response to at least (i) one or more input parameters from a temperature-viscosity curve characterizing the glass melt, (ii) one or more input parameters from one or more temperature dependent impedance response models of the glass melt, and (iii) ?Z, where ?Z represents a degree to which an impedance condition ZY of the ultrasonic probe differs from a reference impedance ZR when the ultrasonic probe is positioned in the glass melt.