Automatic Operation Mode Research Articles

Gracefully-degraded operationable control system for the UVSOR synchrotron radiation source and its operational experience

The UVSOR control system for the 750 MeV electron storage ring as a dedicated VUV (Vacuum-ultraviolet) synchrotron radiation source is described. When a failure occurs in the control system, it can provide gracefully-degraded operation to resume control of the storage ring without a fatal shutdown. The control system comprises two Micro-VAX 3400's used for process computers, two workstations for operator consoles and mainly CAMAC interfaces for accelerator devices. The control system also provides various automatic operation modes of the storage ring for user experiments, such as: (1) multi-bunch operation with/without a superconducting wiggler, (2) single-bunch operation and (3) machine-study operation. An operator can initiate one of these modes using menus on X-Windows on the workstation. Operational experience has shown that the control system can successfully operate the storage ring even when a failure occurs.

Comparison of beam‐hardening and K‐edge filters for imaging barium and iodine during fluoroscopy

This study investigated the dose reduction performance of several beam-hardening and K-edge filter materials for the imaging of barium or iodine during fluoroscopy. A computer model was developed to simulate the effect of added filtration on entrance exposure rate (Xp), integral dose rate (Di), contrast (C), signal to noise ratio (SNR), imaging performance per dose (SNR2/Di), and tube load. The model incorporated the response characteristics, in both manual and automatic control modes of operation, of fluoroscopic systems to increasing or decreasing x-ray intensity at the input of the image intensifier. Input parameters to the computer model included choice of filter material and thickness, a barium or iodine test object, tube potential, phantom thickness, a CsI input phosphor, and a set of algorithms for controlling the fluoroscopic system. In all cases, the performance of systems with added filtration was judged with respect to a reference system operating under comparable conditions. In general, either beam-hardening or K-edge filters provided a significant reduction in entrance exposure and integral dose rates, but with an attendant increase in tube load. For a fluoroscopic system constrained to follow a representative automatic brightness control algorithm, added filtration provided a reduction in entrance exposure and integral dose rates for all phantom or uniformly distributed barium thickness. However, the imaging performance per dose, in some cases, decreased rapidly and was less than that of the reference system at large thicknesses. Only as change in the algorithm controlling the kVcp and mA operating points on the fluoroscopic system provided an imaging performance per dose greater than the reference system's at large thicknesses. The practical implementation of adding filtration to fluoroscopic systems is most simply accomplished with beam-hardening filters rather than K-edge filters. However, the systems with K-edge added filtration can provide slightly better performance when used over a limited range of phantom thicknesses such as the range normally associated with pediatric patients.

Automatic working primary standard of emf in the 1 to 10 V range

An automatic emf working primary standard in the 1 to 10 V range developed at the Scientific Production Association of the D. N. Mendeleev All-Union Scientific Research Institute of Metrology is described. The primary standard complies with GOST8.027-89 and its design is based on two groups often saturated standard cells each mounted in a single thermostat. The field of application, the construction, and the operation of the primary standard in automatic, semiautomatic, and manual operation modes are described. The equipment constituting the primary standard has been analyzed and put into practical use.

The safety assessment of human-robot systems. (4th report Evaluation of hazard control measures for an industrial robothandling work pieces)

An actual unmanned manufacturing station consisting of an NC machine and an industrial robot is assumed. The main hazards of the robot to a human, which occur during troubleshooting in an automatic operation mode, are enumerated using Action-Chain-Models. Fault Trees of accidents caused by the hazards are given as subsets of Logic Models for the Analysis of Accident-Causation-Mechanisms, and minimal cut structures are represented by Priority-AND gates to consider sequential properties of basic events. Furthermore, a manual safety mechanism, an automatic one, and a combination of the two, which cut off the power sources of the robot when a human enters a hazardous zone, are evaluated by comparing expected numbers of occurrences of the top events.

Mueller-matrix measurement using the four-detector photopolarimeter

A scheme for complete, accurate, and fast determination of the Mueller matrix M of elastic light scattering by a given sample is presented. The Stokes vector of the scattered radiation is virtually instantaneously measured using the recently described four-detector polarimeter (FDP) [Opt. Lett. 10, 309 (1985)] for various input polarizations generated by a fixed polarizer followed by a quarter-wave retarder (QWR) of adjustable fast-axis azimuth C. The output signal vector I of the FDP is recorded at four or more settings of C. If the periodic function I(C) is Fourier analyzed, a series of four terms is obtained whose coefficients determine M column by column. The QWR azimuth C can be changed manually, by a stepping or synchronous motor, or by Faraday-cell magneto-optical rotation, leading to various semiautomatic and fully automatic modes of operation with a range of speed to suit various applications.

The safety assessment of human-robot systems. 4th report Evaluations of hazard control measures for an industrial robot handling work pieces.

An actual unmanned manufacturing station consisting of an NC machine and an industrial robot is assumed. The main hazards of the robot to a human, which occur for the troubleshooting in the automatic operation mode of the system, are enumerated using the Action-Chains-Model. The Fault Trees of the accidents caused by the hazards are given as the subsets of the Logic Models for the Analysis of the Accident-Causation-Mechanisms, and the minimal cut structures are represented with Priority AND Gates in consideration of the specifications of the basic events. Furthermore, the hazard controllability of a manual, an automatic, and a combined mechanism to cut off the power sources of the robot when human enters the site are evaluated by comparing the expected numbers of occurrences of the respective top events.

Production system for 18F-2-deoxy-2-fluoro-D-glucose--a trial for automatic production.

We have developed a production system for 18F-2-deoxy-2-fluoro-D-glucose (18F-2FDG), which assures reliable production with easy handling and reduces radiation exposures to the operator. Chemical procedures in this system are the same as manual method developed in NIRS. This system has 2 operation modes; one is remote controlled manual operation mode and the other is microcomputer controlled automatic operation mode. In remote controlled mode, we tested this system 5 times and 18F-2FDG synthesized was supplied for clinical use once. The mean radiochemical yield of 18F-2FDG from the target gas recovery with decay time correction was 8%, that is the same as in the manual synthesis. It took about 2 hours from end of bombardment (EOB) to end of synthesis (EOS). Since this time is shorter than in manual synthesis, the available activity at EOS is increased.

Variation Among Gross Energy Values Measured by Two Modes of Adiabatic Oxygen Bomb Calorimetry

A master control for an adiabatic bomb calorimeter introduces two automatic modes of operation, but little is known about the variances of data derived by each mode. Nine samples were assayed in duplicate using each mode on each of 5 days. The resulting data were subjected to analyses of variance to compare the two modes and to estimate components of variance among and within days. The mode had no effect on the gross energy estimates. When sunflower oil and tallow were assayed, the within-day standard deviation was approximately three times greater with the rapid mode than with the reference mode. None of the other 7 samples showed significant differences between modes. Such day-to-day differences as were observed were not consistent over the materials assayed and cannot be attributed to calorimeter operation nor to environmental changes.For most gross energy measurements of feedingstuffs and excreta, the rapid mode appears to produce satisfactory data of high reproducibility. The rapid mode permits a greater throughput of samples than conventional adiabatic calorimetry equipment or than the reference mode; up to 35 samples per 7.5 hr day are assayed in this laboratory.

An automated microcomparator for ultracentrifuge interference fringe measurements

An automated device for reading the fringe patterns produced by interference optics in an analytical ultracentrifuge has been designed and tested. The device significantly reduces the time and work required to read these photographs while improving the precision over manual reading. Fringe edges are detected by a differential system and fringe centers estimated from the edge positions. Both semiautomatic and automatic modes of operation are described. In the latter, the device has been interfaced to a PDP-7 minicomputer.

An Accurate Spectrophotometer for Measuring the Transmittance of Solid and Liquid Materials.

The optical transmittance of solids and liquids as well as the molar absorptivity of various chemical species are parameters of fundamental significance in characterizing these materials. Meaningful transmittance data can be obtained only when the measurements are performed with well-known accuracy and precision. To perform such measurements, a high accuracy spectrophotometer was designed and assembled at NBS, Analytical Chemistry Division, and will be described in this paper. This single-beam instrument is composed of a constant radiation source, a monochromator, a sample carriage, an integrating sphere-photomultiplier assembly followed by appropriate electronics, and a read out system consisting of a digital voltmeter and a computer data acquisition and handling provision. The accuracy of transmittance measurements is determined by the light-addition principle used in conjunction with a two-aperture arrangement. The spectrophotometer can be used in manual or automatic modes of operation. A detailed discussion of the data obtained with this instrument, used in both modes, will be presented together with its application to the certification of solid and liquid Standard Reference Materials for checking the photometric scales of conventional spectrophotometers.

An Automated 20-20,000-cps Transmission Measuring Set for Laboratory Use

An automated loss and phase measuring set has been developed to measure, in a point-by-point fashion, two-port networks over the frequency range from 20 to 20,000 cps with a maximum accuracy of 0.01 db and 0.1 degree. Manual, semiautomatic, and automatic modes of operation are provided. During automatic operation, the interval between successive data points is determined by programmed intervals of frequency, loss, and phase. These quantities are programmed either separately or in combination. Machine selection of the measurement points is controlled by comparing the program with information fed back from the signal oscillator and the measured circuit. At each selected point, frequency is measured, loss and phase are determined by self-balancing standards, and these data are recorded on punched tape

Infrared Automatic Acquisition and Tracking System

A technique for accumulating airborne visible and infrared spectroradiometric data from missile plumes and re-entry objects establishes the requirements for a precision tracking front surface mirror. The processing of target radiation, reflected by the tracking mirror into an infrared tracker telescope, to derive target coordinate information, is described. The derivation of transformed target error signals to command the motion of the hydraulically driven tracking mirror is outlined. A description of the servo-electronics system, with selected circuitry, is given. The dynamic characteristics of the system, as determined from preliminary field tests, indicate that the system has a tracking rate capability of 10°/sec with an accuracy better than 60 seconds of arc. The detection sensitivity of the infrared tracker telescope is 1.6×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-10</sup> w/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in the 2-to 6-α region, and is sufficient to provide 10-miile tracking ranges against a jet target in a sunlit cumulus cloud background. In a typical installation, aiming of the tracking mirror is provided by a 7×35, 10° field of view sighting telescope which is automatically slaved by the tracking mirror when acquisition and target tracking occurs, thereby providing continuous observation of the target. As an alternative to visual aiming, an automatic search program is generated by an accurate electro-mechanical programmer, which is described. Target acquisition, in an automatic mode of operation, is accomplished through the use of a simple logic circuit which provides electronic background discrimination by virtue of signal pulse width.