Abstract: A disk drive is disclosed comprising a velocity extraction circuit for extracting a velocity of an actuator arm from a back EMF voltage across a voice coil of a voice coil motor when embedded servo information is unavailable. The velocity extraction circuit comprises a dual slope integrator for integrating a voltage representing a current flowing through the voice coil and the voltage across the voice coil. The sum of the integrations cancels the resistance of the voice coil from the back EMF measurement. In one embodiment, the dual slop integrator also integrates the reverse polarity of the voltage representing the current flowing through the voice coil and the reverse polarity of the voltage across the voice coil in order to cancel the inductance (L·di/dt) of the voice coil from the back EMF measurement.

Abstract: The system includes a back panel that attaches to the backrest of the wheelchair. The back panel is ornamented and/or decorated in a selected motif. A top element and side panel elements are provided that attach to the back panel. The top element extends above the occupant of the wheelchair and the side elements protrude from the side of the wheelchair. Both the top element and the side elements are ornamented and/or decorated in the same motif, as is the back panel. Decorative wheel attachments are also provided. The decorative wheel attachments attach to at least two of the wheels of the wheelchair, wherein the decorative wheel attachments share the same ornamentation motif as do the other elements in the assembly.

Abstract: A disk drive that includes a base, a magnetic disk, a rotary actuator that carries a head for reading and writing data from the disk in a track-following mode under the control of a servo control system, and at least two sensors—one fixed sensor rigidly coupled to the overall disk drive and one mobile sensor mounted to the rotating actuator—for differentially detecting accelerations of the rotary actuator relative to the overall disk drive and its disk. The disk drive detects and actively compensates for accelerations imparted to a balanced actuator that has an effective imbalance. The fixed sensor is preferably mounted to a PCBA that is secured to the base. The mobile sensor is preferably mounted to an actuator arm of the rotary actuator, as far outboard as possible, and so as to align with the fixed sensor as the rotary actuator swings through its range of travel. The preferred sensors are linear accelerometers.

Abstract: A disk drive includes a head disk assembly having a housing including a first surface area, and a strain transducer for producing a strain signal representing strain in the first surface area due to a mechanical shock on the disk drive. The strain transducer includes a first electrode, a second electrode, and a volume of piezosensitive material defining a second surface area. The piezosensitive material is disposed between the first electrode and the second electrode. The first surface area overlaps the second surface area. The strain transducer further includes means for securing the first electrode and the piezosensitive material to the first surface area such that the strain in the first surface area is replicated in the piezosensitive material. The disk drive includes means responsive to the strain signal for controlling a write operation in the disk drive.

Abstract: An ankle and hip exercising apparatus for exercising the ankle and hip using dorsi ankle flexion, plantar ankle flexion, ankle rotation, and hip rotation. The user may use unidirectional resistance for strength and range of motion development, or bidirectional resistance to develop proprioception. The foot is held in place by an overshoe having a sole with divots, mating with a shaft having a rounded top. Resistance is provided by elastomeric resistance members such as surgical tubing. The ankle exerciser's base board includes angle measurement indicia to provide feedback for range of motion improvement. A unique combination disc and hemispherical ball support is used to distribute weight which produces stress about the ankle in various areas of the foot. The device may be used while sitting or standing, depending on the type of exercise desired.

Abstract: A process for the manufacture of ether from a feedstock containing isoolefins and linear olefins. The process is one which has a high conversion of isoolefins thereby permitting the separation of linear olefins without the associated difficulty in separating isomers.

Abstract: A disk drive controller having a microprocessor and a sampled signal head positioning system measures and stores the relative rotational offsets between heads arranged in a stacked relationship and respective servo wedges on different disk surfaces. The offsets are stored in a table and subsequently applied to a servo wedge detection circuit to ensure that a next sequential wedge is detected after a head switch.

Abstract: A digital-to-analog converter (DAC) is preferably employed to receive a digital input word and provide an analog output signal to a motor driver in a disk drive servo. The digital input word has a plurality of bit positions for establishing a resolution for the DAC. These bit positions define first and second groups of bits. The DAC comprises circuitry responsive to the first group of bits for producing a pair of analog signals defining a common-mode magnitude and a differential magnitude. The common-mode magnitude is a function of the value of the first set of bits and the differential magnitude is a function of the number of bit positions in the first group of bits.

Abstract: This invention provides an improved etherification process that reduces the amount of acidic-ion-exchange-resin catalyst that is deactivated by nitriles. This process uses a water phase to remove nitriles from a hydrocarbon phase followed by an alcohol phase to remove the nitriles from the water phase. An hydrogenation catalyst is used to convert the nitriles to amines so that they can be more easily removed from the alcohol phase.

Abstract: A combination process wherein a hydroisomerization system provides a hydrocarbon feed for an etherification system wherein unreacted alcohol is separated from the etherification effluent and passed to the fractionation column used in the hydroisomerization system so that water entrained in the unreacted alcohol can be separated from said alcohol within said fractionation column.

Abstract: This invention provides a process to remove nitriles. This invention also provides an improved etherification process that reduces the amount of acidic-ion-exchange-resin catalyst that is deactivated by nitriles. These processes use a water phase to remove nitriles from a hydrocarbon phase followed by a steam, or fuel gas, phase to remove the nitriles from the water phase.

Abstract: A disk drive for operating in an environment in which the drive is subject to physical shock includes a circuit which senses movement of a transducer head support arm which result from a shock's rotational component. The rotational shock is detected as a residual BEMF signal in the drive's VCM coil winding. The residual signal is extracted from much larger position control signals that are applied to the VCM winding during normal system operation by providing circuits that simulate the VCM winding voltage caused by the position control signal and subtracting the outputs of the simulation circuits from the actual VCM coil winding voltage. This eliminates the normal operating components and leaves a residual signal that represents only the small portion of the VCM BEMF signal that results from the rotational shock. A threshold circuit compares the shock BEMF signal to a predetermined threshold. If the BEMF signal exceeds the threshold, disk drive write operations are aborted.

Abstract: A process for producing ethyl tertiary butyl ether and for the substantially complete recovery by fractional distillation of the unreacted ethanol contained in an etherification reaction zone product stream as a product along with the ethyl tertiary butyl ether reaction product. This process utilizes methanol as a fractionator feed additive to enhance the recovery of ethanol as a bottoms product.

Abstract: A process for producing a high purity ether product. This process includes utilizing an additive stream, which preferably contains isobutane, to alter compositions of the overhead and bottoms products of an etherification effluent fractionator so that the alcohol concentration in the overhead product is less than that of the azeotropic composition.

Abstract: A transmission control system includes a plurality of hydraulic pressure operated control elements for engaging a gear of the transmission in response to actuation of a shift control lever having neutral and non-neutral positions, a plurality of control valves for controlling pressurization of the control elements and a pump for supplying pressurized fluid to the control valves. An engagement override system includes a switch which is coupled to the shift lever and which energizes a solenoid when the shift lever is in its neutral position and de-energizes the solenoid when the shift lever is in its non-neutral position. In a preferred embodiment, an engagement override valve includes a pilot operated valve which controls communication between the pump, a reservoir and the pressure operated control elements. The solenoid controls the pilot operated valve.

Abstract: A novel integrated olefin processing scheme is provided where olefins and paraffins are processed to produce high octane gasoline blending components. The integrated process involves the dehydrogenation of paraffin compounds to olefin compounds and the processing of olefins by hydroisomerization to produce hydroisomerate streams which are subsequently etherified. Those olefin compounds which are not etherified pass to an alkylation process where they are alkylated with branched chain paraffin compounds to produce an alkylate product.

Abstract: An etherification process for reacting tertiary olefin compounds with primary alcohols to produce an ether product. The etherification process has the advantage of permitting dual operating modes for producing methyl tertiary butyl ether and tert amyl methyl ether and it provides high conversion across the etherification process of the tertiary olefin compounds.

Abstract: In a process for producing a 3-halo-halobenzene or a 1-halo-3,5-dihalobenzene, a 2-halo-4-haloaniline or 2-halo-4,6-dihaloaniline is mixed with a deaminating agent. The 2-halo-4-haloaniline or 2-halo-4,6-dihaloaniline is deaminated so as to form a corresponding 3-halo-halobenzene or 1-halo-3,5-dihalobenzene.

Abstract: Aromatic amine compounds are halogenated in the presence of a quaternary ammonium halide.

Abstract: A process for the production of 2,4-dihaloaniline, especially 4-bromo-2-fluoroaniline, via the halogenation (bromination) of 2-haloaniline (2-fluoroaniline) in the presence of quaternary ammonium halide (bromide) catalyst in an inert solvent. The yield and selectivity are very high and the inventive method includes continuous processing with recycle of the catalyst/solvent mixture.