Abstract: A loudspeaker driver of the dynamic type is designed to be as efficient as possible within only the constraints of cost and material limitations. The resistance of the speaker's voice coil is designed to have only a portion of the total resistance. An external resistor is wired in series with the voice coil to optimize the speaker for use in systems for sound reproduction. The external resistor is placed so that heat dissipated in the external resistor cannot significantly influence the temperature of the voice coil. The external resistor can be made of pure metal, alloys, carbon or use a temperature-dependent diode for the resistor. Different advantages are found in each embodiment. The invention reduces the effects of voice coil heating, inductance and the negative effects of interaction between voice coil and currents in the central pole piece of the loudspeaker.

Abstract: An arrangement is provided for insuring that excessive demand is not placed on a refrigeration unit that supplies pressurized subcooled refrigerant to different channels having independent needs for use of refrigeration capacity. A separate reference channel receives a portion of the refrigerant and expands the refrigerant fully to a gas phase to establish a minimum level reference temperature. In the operative channels the refrigerant flows into individual evaporators/heat exchangers at rates set by external command signals, the refrigerant being in heat exchange relation with thermal transfer fluid in the evaporator/heat exchanger. Evaporation of refrigerant in each channel thus brings the thermal transfer fluid for that channel to the target temperature. By comparing the post evaporation temperature in each channel to the reference temperature, and reducing the refrigerant flow rate whenever the difference is below a threshold, individual channels are not overtaxed and the system remains stable.

Abstract: A temperature control unit for independent control of a number of independent channels, as can exist with a cluster tool used for semiconductor fabrication, has high efficiency, long term life and reliability, and requires only a small floor area. To these ends, the unit employs a single high capacity refrigeration system and disposes a number of separate temperature control channels for the individual tools, with only some channels receiving refrigerant. Low temperature channels use high pressure, sub-cooled refrigerant for chilling the heat transfer fluid to selected levels controlled by proportional valves adjusting refrigerant flow through evaporator heat exchanger units which cool heat transfer fluid. Moderate temperature channels cool the heat transfer fluid for associated tools to an ambient temperature level.

Abstract: A system for pressurizing and pumping a fluid that may undergo substantial variations in temperature utilizes a motor with an enclosed rotor disposed adjacent and in driving relation to a centrifugal pump, but thermally isolated even though the fluid being pumped serves to establish hydrodynamic effects at large journal bearings supporting the rotor and the pump. The rotor is in magnetic interchange relation with an associated stator through a magnetic housing which, together with a pump mount coupling the motor to the pump, is fully encloses, apart from pump inlet and outlet apertures. The pump mount includes a low diameter neck portion about the shaft teat has low axial heat conductivity, thus providing an isolation spacing that also is filled with insulation material to eliminate significant convective heat transfer.

Abstract: A method executed in a computer system for detecting and handling an invalid use of a data structure is described. The method includes the steps of providing a data structure associated with a first computing environment. The data structure includes a field having a value stored therein identifying an inaccessible address in a second computing environment. This field is used in detecting an invalid use of the data structure in the second computing environment by a computer program attempting to access memory using said inaccessible address indicated by said value contained in the first field. Additionally a preferred data structure is described as are alternative embodiments of detecting an invalid use of a data structure.

Abstract: A refrigerator for rapidly cooling down and then maintaining a plurality of wine bottles of arbitrary configuration within a selected temperature range comprises a compression type refrigeration unit in association with the refrigerated compartment which receives the wine bottles. The refrigeration unit includes a controllable expansion valve and a control system in which a microcontroller is arranged with a plurality of stored cooldown models as references for bringing the wine bottles to temperature without damage to the wine. Temperature, pressure and air flow measurements are used by a computer programmed to determine the status of the thermal load as affected by the number of wine bottles and their temperatures, and to adjust variations in the load compartment temperature for both cooldown modes and a steady state mode. Given an arbitrary thermal load, the refrigerator system lowers the wine temperature in a maximized but controlled manner so that chilled wine is available in no more than 30 minutes.

Abstract: To dissipate heat generated internally in integrated circuit units, both an active refrigeration system and a passive refrigeration system are coupled to a heat sink that engages the integrated circuit unit. A cold probe insertable into the heat sink has an interior heat exchanger and receives high pressure but ambient temperature refrigerant which is subcooled and expanded to provide cold liquid refrigerant about the interior heat exchanger. As thermal energy from the circuit unit evaporates refrigerant, the refrigerant passes back to a power refrigeration unit for recirculation. A passive backup unit functions if the cold probe operation fails for some reason by boiling off a second refrigerant in a chamber at the heat sink and condensing the gases within a spaced apart air heat exchanger. Refrigerant that recondenses within the air heat exchanger flows by gravity back into the boil off chamber.

Abstract: A method for correcting higher order distortion introduced in a complex multifrequency waveform by an element which introduces signal-induced nonlinearities uses a replica of the non-linear element as a part of a high gain electronic feedback circuit between the output and an input of an amplifier. The replica of the non-linear element receives the multifrequency waveform, and is driven to duplicate the non-linear effects, which are used to generate a compensating voltage which is compared to the voltage obtained from the non-linear device. The resultant difference voltage after the comparison and amplification is then closer to the original signal. Thus, in an audio system for example, distortions which are audibly apparent to the human ear but so small they are immeasurable by instrumentation can be eliminated or minimized by employing a number of replicas in the same fashion.

Abstract: The distortion effects introduced in a complex multifrequency wave by parametric variations in individual active elements arising from signal and power supply variations in a circuit, such as an audio amplifier, are compensable through the use of replicas of the active elements, and the generation of a feedback signal incorporating comparable distortion. By high gain amplification of the feedback signal in a differential amplifier receiving an input signal that is not comparably distorted a comparison signal is derived containing distortion components. The comparison signal is used in a feedforward path which includes the circuit that is subjected to parametric variations in a sense to cancel the introduced distortions.

Abstract: In sound generating systems, it has been ascertained that various factors cause spurious, audible emanations when transducers of reasonable size and cost are driven in complex motions characteristic of typical high fidelity audio reproduction. In a typical system in which different transducers are used for different frequency ranges, the spurious emanations are reduced by change of amplitude or frequency or both, without affecting transducer performance, to levels at which they are substantially inaudible. Means are coupled to each speaker in a multispeaker system for compensating for mass, compliance and damping. Further, crossover means are provided for introducing opposing signal components in a crossover range between two adjacent range speakers such that opposing signal components are acoustically cancelled in the composite output.

Abstract: In sound generating systems, it has been ascertained that various factors cause spurious, audible emanations when transducers of reasonable size and cost are driven in complex motions characteristic of typical high fidelity audio reproduction. It is shown that phase effects, unidirectional components, and transient (start-stop) effects give rise to such spurious emanations and that these center about the resonant frequency of the transducer. Means are disclosed which significantly improve the clarity of reproduction by minimizing these spurious emanations. In a typical system in which different transducers are used for different frequency ranges, the spurious emanations are reduced by change of amplitude or frequency or both, without affecting transducer performance, to levels at which they are substantially inaudible. Either or both electronic and acoustic techniques may be used for these purposes.

Abstract: A passive survival suit for enabling a diver in a confined bell to maintain body temperature for at least a minimum interval in the event of failure of external thermal sources uses a combination of thermal insulation and a coacting breathing gas regenerator and scrubber system. The thermal insulation comprises a combination of a hooded sleeveless vest and a body shell, each of which provide a long heat conduction path length and minimum internal heat convection currents. The regenerator and scrubber system are arranged such that thermal energy in expired breathing gases is stored with high efficiency and used to heat breathing gas during intake, while the carbon dioxide scrubbing reaction is carried out in an optimal warm, moist atmosphere and contributes heat to aid in maintaining the diver's temperature.

Abstract: A hot gas engine is provided that supports internal combustion in a gas mixture maintained at high pressure and in a controlled temperature range. With air as the essential working fluid, an oxygen rich mixture is cycled in a semi-closed loop system supportive of combustion but nonetheless providing work in the fashion of the known Stirling cycle. The arrangement includes a high area, short path length regenerator that contributes to high work efficiency despite the use of a relatively high density working fluid. The high temperature chamber of the system includes an interior layer of self supporting permeable insulation, and confines the working fluid without significant heat loss. An air compressor-expander system is coupled to replenish air in the internal gas mixture at compatible pressures and temperatures and without imposing substantial work loads. Catalytic agents may be disposed in the system for greater burning efficiency.