Abstract: A liquid scintillation solution consisting of a fluor and a select solvent is presented, said solvent having the generic formula ##STR1## where R.sub.1, R.sub.2, and R.sub.3 are either a methyl group or a hydrogen atom.

Abstract: A vial holder for a septum closed vial is disclosed which vial holder enables automated vial insertion to and withdrawal from puncturing hypodermics for the removal of contents or the communication of electrodes to liquids within the sealed vial. The vial--a commercial item of manufacture--includes a cylindrical glass body closed at the bottom and terminating upwardly at a narrowed neck to an opening. The opening accommodates both a septum and a septum retaining cap. A vial holder having an inside vial containing cavity with inside dimension complementary to the outside dimension of the vial is disclosed. This vial holder is formed from elastic material such as semirigid commercially available plastics and is vertically slotted from an open top at least partially to and towards the bottom of the holder. The vial holder is provided at the open top with inwardly extending fingers which register to the outside of the narrow neck of the septum sealed vial.

Abstract: In a centrifuge rotor with defined and discrete sample receiving cells, an improvement to the fastening of a lid on top of the rotor by a bolt for preserving gas pressure on sample is provided. The rotor is of the type having a rotor body and rotor adaptor for attachment to a drive hub. Typically, a male control surface on the drive hub mates with a corresponding female mating surface on the rotor adaptor. The mating surfaces include paired opposed pins on the rotor adaptor received in grooves on the drive hub. A central aperture along the spin axis of the rotor is provided through the rotor body. This aperture is provided for viewing the rotor coupling at the pins to the grooves in the drive hub as well as providing a path through which a bolt can attach a lid on the top of the rotor to the drive hub with the rotor compressed therebetween the lid and drive hub, a sample preserving atmosphere may be maintained in the rotor during centrifugation.

Abstract: A centrifuge system includes a drive shaft bearing mounted to a drive shaft for engaging a solenoid actuated plunger in low friction contact over a predetermined angular velocity range of the drive shaft. The drive shaft bearing includes a frustoconical bearing surface that contacts a plunger bearing mounted in an end of the plunger when the solenoid actuates the plunger. The frustoconical bearing surface transforms vibrations of the drive shaft transverse to its axis of rotation into linear motion of the plunger relative to the drive shaft. The plunger is mounted inside the solenoid such that the solenoid, the plunger and the drive shaft are substantially concentric. The plunger is movable in the solenoid in response to application of an appropriate electrical current to the solenoid. However, the plunger fits sufficiently close within the solenoid that the force movement of the plunger arising from contact with the vibrating drive shaft bearing is damped by friction between the solenoid and the plunger.

Abstract: A flow cell for liquid scintillation counting having a spool wound with a length of light transparent tubing provides a variable volume of sample solution for analysis by selectively winding the spool with a select length of tubing, thus controlling sensitivity of anaysis and maintaining resolution of separated constituents in the sample. The flow cell comprises a spool rotatably held within a framework and which may be covered with a transparent material.

Abstract: To enable centrifuging to occur at precisely determined sample temperatures, a method of centrifuge calibration which permits rapid and accurate refrigeration of the rotor containing the sample is disclosed. A rotor with sample to be centrifuged is placed within a centrifuge can. Temperature of the radiometer T.sub.ra, and temperature of the surrounding refrigerating can T.sub.c is determined at a first time, t.sub.0. Thereafter, and at a second time t.sub.1, temperature of the radiometer T.sub.ra, and the temperature of the surrounding refrigerating can T.sub.c are equilibrated. The temperature excursion between t.sub.0 and t.sub.1 for the temperatures of the radiometer T.sub.ra and the temperature of the refrigerating can T.sub.c are measured to yield respective .DELTA. T.sub.ra and .DELTA. T.sub.c. The radio of .DELTA. T.sub.ra /.DELTA. T.sub.c is taken to give a constant which comprises the view factor from the radiometer for the particular shape of rotor and the surrounding can.

Abstract: A centrifuge sample is optically scanned during centrifuging. The sample, placed in a centrifuge rotor having a cell with top and bottom windows, is spun until stratification and discrete layering occurs within the sample. Such layering occurs on layers that are precisely normal to the radius of the centrifuge at the point of sample and parallel to the spin axis of the centrifuge. A slit scanner having a slit normal to the sample plane transverse the width of the sample below the cell to detect with precision the precise location of the strata in the cell. A light source is reflected by a toroidal mirror having two radius of curvature. One radius of curvature is selected to collimate rays of light parallel to the layer of the sample. The mirror is ruled with respect to the other radius of curvature to chromatically classify light to preselect band width. Rotation of the mirror preserved collimation but enables selected scanning light frequency.

Abstract: An apparatus and method of protecting a centrifuge from rotor overspeed and resultant mishap by computation of the rotor moment of inertia is disclosed. In the preferred embodiment, a centrifuge is driven by a rotor mounted on a shaft which shaft is in turn driven by a constant current motor. A tachometer for detecting angular velocity of the drive shaft is used. A desired and ultimate centrifuge operating speed is selected by the operator. The times at which the rotor passes through discrete speeds are recorded and from the time difference the moment of inertia is computed. The moment of inertia can thereafter be utilized to discretely identify or "finger print" rotors to disqualify certain rotors from use in particular centrifuge protocols and establish gross limits of centrifuge operating speed.

Abstract: The present invention provides a mechanism for bolting a rotor to a hub without introducing excessive radial stress around the bolt holes when the rotor is operating at high speed. The rotor has a slot cut through its center to eliminate radial stress perpendicular to the slot and thereby avoid the problem of stress cracking of the otherwise weak section. The mounting bolts are necked down and not threaded at the surface of the hub. The bolts are threaded into the hub at a substantial distance from the top surface of the hub so that they can flex and so that the center of the rotor can move out relative to the hub. The hub rotor interface is lubricated to facilitate radial motion of the center of the rotor.

Abstract: An improved centrifuge. The centrifuge may be a conventional centrifuge having a rotor and a plurality of tube receiving adaptors inserted into the rotor in a circular configuration. The improvement comprises a flexible flap having a fixed end mounted on the rotor at an adaptor and having an opposing free end. The free end extends radially inward toward the center of the rotor when the rotor is not rotating and is folded by centrifugal force back to cover the opening in the adaptor when the rotor is rotating. By covering the opening in the adaptor, the flexible flap eliminates the high pitch whistle otherwise generated by the adaptor when rotating without a tube inserted.

Abstract: A fluid pump for use in high performance liquid chromatography having a piston movable in a chamber for drawing fluid into, pressurizing, and delivering the pressurized fluid from the chamber. A pressure transducer in the chamber derives a pressure output signal indicative of chamber pressure. Means is provided for correcting offset errors in the pressure output signal.

Abstract: A salt belt for insertion into a centrifugal test rotor is provided which is used to hold and contain a plurality of test components during mechanical testing. The slat belt is a flat polymeric belt which adhesively affixes a plurality of L-shaped slat members to its upper surface. When the belt is laid flat, it accommodates the easy positioning of components into channels. As the belt is curled for insertion into the test rotor, the slats move closer to one another and clasp the components into channels formed by adjacent pairs of radially directed slat arms. Upon completion of the test run, the slat belt is removed from the rotor and unrolled whereby the components are easily removed from the belt.

Abstract: The present invention provides an improved rotor for a centrifuge that operates by centrifugal elutriation. The rotor consists of a chamber assembly, a disk assembly, and a quick release mechanism. The chamber assembly is relatively light and it includes one or two separation chambers, tubing and a rotating seal. The disk assembly consists of the relatively heavy support structure. The two piece construction facilitates handling the parts of the rotor that generally need to be autoclaved. The chamber assembly has a novel structure that allows the rotor to easily be configured for operation with one or two chambers. The disk assembly has a unique strain relief that prevents structural cracking. The quick release mechanism is held in the latched position by centrifugal force during operation of the rotor.

Abstract: A composite material centrifuge rotor and process of construction of the rotor is disclosed. A rotor having high stiffness of fibers, preferably carbon, bound together with resin is disclosed. The rotor includes a top disk, a bottom disk and a spacer belt spacing the two disks apart to form a rotor assembly. The top and bottom disks are fabricated by overlying multiple layers of tape, the tape being made from longitudinally extending and parallel fibers held together with resin. Successive layers of tape are oriented so as to vary the longitudinal direction of the fiber with respect to a preselected radius vector from the spin axis of the rotor. When the tape is compiled in multiple layers to a thickness of the top and bottom disk, the tape is compressed between two metal plates and cured at a temperature well above the expected autoclave temperature of sterilization of the rotor. Thereafter, the entire assembly is wound by a peripheral belt with resin impregnated high stiffness fiber.

Abstract: A springless floating coupling for a plunger type pump connecting the drive plunger to a driven piston.

Abstract: A liquid boundary level detector employing an open-ended conduit which directs pressure waves toward a liquid boundary layer. The conduit is moved from a starting position toward the liquid boundary and, upon contact with the boundary, there is a change in acoustic impedance within the conduit. This change is monitored and a signal is generated indicative of such contact. Once the initial liquid boundary position is determined, that may become the reference position for subsequent liquid boundary measurements or motions.

Abstract: A thermoelectric cooling design of the type having a nonconducting substrate mounting thermoelectric coolers is improved. Provisions for a flexible can and improved heat dissipation from the thermoelectric coolers are provided. For improved thermal response, the refrigerated vacuum can is provided with thin walls of high purity aluminum with the result that deformation of the wall surface, especially the bottom wall surface can occur both with respect to installation. A plurality of can heat sinks are placed on the walls of the can to form a unitary and locally rigid side wall to the can at the point of attachment. At least one thermoelectric cooler is communicated to the can heat sinks at a first side for receiving heat energy from the can. A second discharge heat sink is communicated to each thermoelectric cooler for dissipating heat energy from both the can and the thermoelectric cooler.

Abstract: A composite material centrifuge rotor and process of construction of the rotor is disclosed. A rotor having high stiffness of fibers, preferably carbon, bound together with resin is disclosed. The rotor includes a top disk, a bottom disk and a spacer belt spacing the two disks apart to form a rotor assembly. The top and bottom disks are fabricated by overlying multiple layers of tape, the tape being made from longitudinally extending and parallel fibers held together with resin. The tapes are stacked in multiple layers normal to the spin axis of the rotor so as to lie within the plane of the centrifugal force exerted by the rotor. Successive layers of tape are oriented so as to vary the longitudinal direction of the fiber with respect to a preselected radius vector from the spin axis of the rotor.

Abstract: In a double thermal coupled radiometer for preferable use with a centrifuge, an improved radiometer configuration is disclosed. The isothermal radiometic system improved is of the double junction variety (preferably copper-constantan-copper) and includes a black body housing defining a central concavity. The central concavity has a black body disk at the bottom thereof. The disk is preferably suspended by a copper and a constantan wire with one junction formed on the surface of the disk and the other junction formed on the surface of the housing. The improvement includes a plurality of and preferably three annular baffles defining central, circular and preferably concentric opening. These baffles are lodged in the opening of the housing above the mounted radiometer disk. The annular baffles on the side towards the radiation sources are coated as a black body so as to increase the thermal coupling of the black body housing to the ambient being radiometically observed.

Abstract: A composite material rotor is disclosed which is made from a plurality of stacked and bonded epoxied filament wound discs, each disc providing a specially wound construction so that the modulus of the rotor body may be varied in proportion to the maximum stress encountered by the rotor during ultracentrifugation. Such a layered disc assembly allows the rotor to be fine-tuned to respond to a variety of stress encountered during ultracentrifugation. Where upper hoop stress is greater, upper disc 28 might be wound using a higher modulus filament fiber than the fiber used by disc 26.