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  • 1
    Electronic Resource
    Electronic Resource
    Fine structure of the stalk of the bourgueticrinid sea lily Democrinus conifer (Echinodermata: Crinoidea) (1984)
    Springer
    Marine biology 81 (1984), S. 163-176 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Specimens of Democrinus conifer (A. H. Clark, 1909) dredged from about 280 m were fixed aboard ship for transmission electron microscopy. The most important new contributions to stalk histology are the following: an exact description of the different cell types of the stereom spaces; a demonstration of the haemal channel; description of the radial aggregations of cells in the central canal; discovery of coelomic nerves; and discovery of nerve tracts running in association with the aboral extension of the axial organ. The collagenous ligaments of the stalk are separated into three types anatomically (and possibly also functionally). The stalk contains no trace of an axial sinus derived during ontogeny from the anterior coelom (=axocoel). In the roots, the central canal contains a root nerve, but no extensions of the haemal channel or of the coelomic tubes; therefore, roots of bourgueticrinid sea lilies are not homologous to cirri of isocrinid sea lilies or feather stars. The chambered organ and axial organ of D. conifer closely resemble the same organs in feather stars that have previously been described by electron microscopy. The functional implications of our structural results are: (1) cells in the stereom space appear to be a major site of nutrient reserves, (2) the abundant cells with lipid-rich organelles could make the sea lily body more buoyant, and (3) the absence of muscles or other cells specialized for contractility indicates that the stalk of bourgueticrinid sea lilies cannot bend actively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393115
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  • 2
    Electronic Resource
    Electronic Resource
    Design of the vacuum system for the elliptical multipole wiggler at the Advanced Photon Source : The 9th National conference on synchrotron radiation instrumentation (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 3347-3348 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A vacuum system for the Advanced Photon Source elliptical multipole wiggler (EMW) that will operate at a pressure of 10−9 Torr with a storage ring current of 100 mA at 7.0 GeV has been designed and is being fabricated. The major part of the system is a stainless steel chamber with a 66.6 mm by 19.6 mm rectangular cross section. The length of the vacuum chamber is 3100 mm, and the wall thickness is 1.2 mm. Two versions of the vacuum chamber will be produced: with and without distributed nonevaporable getter (NEG) pumping. The version with NEG pumping will have slides on the top and bottom walls to accommodate sintered plates available from SAES. To activate these plates, the entire vacuum chamber will be baked from the outside up to a temperature of 350° C–450 °C. Provision for the baking is included in the design of the vacuum system, its support, and in the EMW itself. The complexity introduced into the design by the need for external activation of the NEG plates is eliminated in the design of the second version of the chamber. In this chamber, a sufficiently low outgassing rate may be achieved by extensive surface cleaning and baking in a vacuum furnace (10−6 Torr) up to a temperature of 950 ° C as has been achieved at the ESRF. Both versions are being pursued in parallel. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147056
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  • 3
    Electronic Resource
    Electronic Resource
    VME insertion device control at the Advanced Photon Source : Papers from the 12th National Synchrotron Radiation Instrumentation Conference (2002)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 73 (2002), S. 1454-1456 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Advanced Photon Source (APS) currently has 29 insertion devices (IDs) installed and operating. The need to remotely diagnose and correct problems has become increasingly important. This has been accomplished through the development of a new control system with greatly enhanced input/output (I/O) capabilities specifically targeted to this control task. The system features a custom VME control card and three rack-mounted interface chassis for ID control, encoder interface, and motor drive shutdown. The card provides device interlocks, limit switch logic, motor axis selection, digital I/O, and status feedback. This VME insertion device control was designed to operate with an eight-axis intelligent motor controller and a stepper-motor drive that accepts step and direction inputs. The front panel of the card has two connectors for all of the control signals for the stepper-motor drives. There is a third connector for the ID limit switch inputs and the emergency stop circuit, and a fourth connector provides 23 bits of digital outputs and 16 bits of digital inputs. Light-emitting diodes indicate which motions are inhibited by the limit switch logic. An experimental physics industrial control system (EPICS) (http://www.APS.ANL-GOV/EPICS) device driver was developed to access all the registers on the VME control card. Using standard EPICS records, the insertion device status can be viewed remotely. This minimizes downtime for APS ID beamline users by allowing faster resolution of any problems preventing a user from operating the insertion device. This new insertion device control has been in use at the APS since July of 1999. The design features of the control system and rationale for them will be presented, along with our experience in building, testing, installing, and operating the control system. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1420757
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