Electronic boards

Defectoscope AUGUR)) is a complex device including Notebook PC with additional electronic boards, small-size automatic two-coordinate scanner, set of piezoelectric transducers, up to 25 m communication line (Fig. 1). 

Due to the pulsed radiation output of the LINAC the detectors and the detector electronics have to handle very high counting rates in very short periods. Therefore the detectors have to work in a mode, where the detector output is integrated for one or several beam pulses. For that purpose the crystals are coupled to photo- diodes. Their currents are read out and analysed by the electronic board, which has been developed for this special application. 

Physically, the MIMOS II Mossbauer spectrometer has two components that are joined by an interconnect cable the sensor head (SH) and electronics printed-circuit board (PCB). On MER, the SH is located at the end of the Instrument Deployment Device (IDD) and the electronics board is located in an electronics box inside the rover body. On Mars-Express Beagle-2, a European Space Agency (ESA) mission in 2003, the SH was mounted also on a robotic arm integrated to the Position... 

Adjustable Workbench (PAW) instrument assembly. The SH shown in Figs. 3.15 and 3.16 contains the electromechanical transducer (mounted in the center), the main and reference Co/Rh sources, multilayered radiation shields, detectors and their preamplifiers and main (linear) amplifiers, and a contact plate and sensor. The contact plate and contact sensor are used in conjunction with the IDD to apply a small preload when it places the SH holding it firmly against the target. The electronics board contains power supplies/conditioners, the dedicated CPU, different kinds of memory, firmware, and associated circuitry for instrument control and data processing. The SH of the miniaturized Mossbauer spectrometer MIMOS II has the dimensions (5 x 5.5 x 9.5) cm and weighs only ca. 400 g. Both 14.4 keV y-rays and 6.4 keV Fe X-rays are detected simultaneously by four Si-PIN diodes. The mass of the electronics board is about 90 g [36],... 

MIMOS II has three temperature sensors one on the electronics board and two on the SH. One temperature sensor in the SH is mounted near the internal reference absorber, and the measured temperature is associated with the reference absorber and the internal volume of the SH. The other sensor is mounted outside the SH at the contact ring assembly. It gives the approximate analysis temperature for the sample on the Martian surface. This temperature is used to route the Mossbauer data to the different temperature intervals (maximum of 13, with the temperature width software selectable) assigned in memory areas. Shown in Fig. 3.21 are the data of the three temperature sensors taken on Mars (rover Opportunity at Meridiani Planum) in January 2004 between 12 10 PM on Sol 10 (10 Martian days after landing) and 11 30 AM on Sol 11. The temperature of the electronics board inside the rover is much higher than the temperatures inside the SH and the contact plate sensor, which are nearly identical and at ambient Martian temperature. 

Fig. 3.21 Example of temperature variation as measured by MIMOS II temperature sensors on MER (i) inside the rover body at MIMOS electronics board (black curve), (ii) outside the rover, at the MIMOS II SH (green and red curves), which is at ambient Martian temperature (a) inside the sensor-head, at the reference absorber position (green), (b) outside the SH at the sample s contact plate (red). Temperatures at the two SH positions are nearly identical (difference less than 2 K). During data transmission between the rover and the Earth (or the relay satellite in Mars orbit) the instrument is switched off resulting in immediate small but noticeable temperature changes (see figure above)...

Memory) (128 KB) on the MIMOSII electronics board. Firmware parameters and the instrument logbook are stored in the nonvolatile memory ferroelectric RAM (FRAM) on the electronics board. There are three individual FRAMs on the MIMOS II electronics board with three identical copies of these parameters to ensure parameter integrity. The copies are compared with each other from time to time to verify that they are identical. If one copy deviates from the other two, it is replaced by a copy of the other two identical parameter sets. All parameters can be adjusted during mission operations. 

MIMOS II has three temperature sensors, one on the electronics board and two on the sensor head. One temperature sensor in the sensor head is mounted near the internal reference absorber, and the measured temperature is associated with the reference absorber and the internal volume of the sensor head. The other sensor is mounted outside the sensor head at the contact ring assembly. It gives the analysis temperature for the sample on the Martian surface. This temperature is used to route... 

Polyfvinyl acetate) (PVAc) latexes produced by batch and continuous emulsion polymerization were used in this study. Details for the apparatus and the polymerization procedure can be found in Penlidis et al. (6,12,K3). Samples taken during the reaction were subsequently analyzed to follow conversion- and particle growth-time histories. The batch experimental runs were designed to yield similar conversion-time histories but different particle sizes. Conversion was measured both off-line, by gravimetric analysis, and on-line using an on-line densitometer (a U-tube DPR-YWE model with a Y-mode oscillator with a PTE-98 excitation cell and a DPR-2000 electronic board by Anton Paar, Austria). A number of runs were repeated to check for reproducibility of the results. Four batch runs are described in Table I below and their conversion histories are plotted in Figure 1. 

Brockwell et al. (1996) described a computerized system for the simultaneous monitoring of place conditioning and locomotor activity in rats consisting of 4 independent conditioning boxes, each equipped with 6 pairs of photosensors connected to an Experiment Controller, an electronic board containing a microprocessor and a programmable timer for storing both instructions and data. 

Ten square silicon chips of 10 nun on a side are mounted in a single row on an electronic board that is insulated... 

DC machines are simpler and cheaper, because their speed regulation is based on scalar controls. For that reason they need simple electronic boards to control the DC electric drive operations. Moreover, they have the advantage that they can be fed by the DC supply already on board. On the other hand, the principal disadvantage is represented by the maintenance required, since for instance brushes need to be periodically checked and changed. Another point to take in consideration is that fuel cell electric vehicles equipped with brushed electric machines would require specific safety devices to avoid that sparks of the collector during the commutation might interact with the hydrogen used as fuel on board. 

Figure 3. Mixing attachment (right) and electronic board for power supply (left) for oxygen consumption measurements adaptable to Eppendorf spectralline photometers (a) changeable cuvette holder thermostatable with separate thermostat (b) cover of the photomultiplier tube (c) motor set for magnetic stirrer (d) switch for power supply (e) potentiometer for stirring frequency (15-1800 rpm).

The heart of the system is a microreactor packaging scheme that is based upon a commercially available microchip socket. This approach allows the silicon-based reactor die, which contains dual parallel reaction channels with more than 100 electrical contacts, to be installed and removed in a straightforward fashion without removing any fluidic and electronic connections. Various supporting microreactor functions, such as gas feed flow control, gas feed mixing, and various temperature control systems, are mounted on standard CompactPCI electronic boards. The boards are subsequently installed in a commercially available computer chassis. Electrical connections between the boards are achieved through a standard backplane and custom-built input-output PC boards. A National Instruments embedded real-time processor is used to provide closed-loop process control and... 

The SPINLINE 3 hardware is a set of modular components, designed, manufactured and qualified specifically for safety applications in nuclear reactors. These components are cabinets, racks, electronic boards or modules and cabling elements between components. They are designed, manufactured and qualified according to nuclear requirements and standards. 

The PDU integrates also high voltage safety features, for example a dedicated safety electronic board, contactors for the galvanic separation, and fuses of the single consumers as well as the coimectors for the high voltage electric wires. 

Because vast amounts of information can potentially be generated in LOC systems and because sophisticated analysis may be required to generate meaningful information from raw data, e.g., for protein analysis or drug discovery, data analysis requires appropriate computational power and speed. Thus, when data volume and analysis complexity are minor, appropriate microprocessors or microcontrollers and affiliated components can be integrated in a hybrid fashion with the microfluidics or, more commonly, included on an external electronics board, eliminating the need for an external computer. 

Electronically The three sub-systems are controlled by the same electronic board knowing that this board has not been considered for this study. 

Andon— 1) An electronic board that provides visibility of floor status and provides information to help coordinate the efforts to linked work centers. Signal lights are green (running), red (stop), and yellow (needs attention). 2) A visual signaling system. 

A prototype electronic mannequin leg developed at the University of Bolton was used to investigate the pressure mapping of bandages. The mannequin leg (Figure 3) simulates a lower limb and has definable tibia, calf and ankle regions. It has 8 pressure-measuring sensors of which 2 are positioned at ankle, 3 at calf and 3 at below l e. The sensors are connected with an electronic board display unit via strain gauges. 

Nickel coated carbon fiber can be used as a conductive plate for fuel cell plates, ice trays and automotive mirror housings an electronic housing to provide EMI shielding for computers, cellular phones, anti-lock brakes, coaxial cable and telecommunication as EMI shielding at electronic board level for computers, cellular phones and 900 MHz phones. Bell and Hansen [251] have described the use of Ni coated fibers for aerospace applications. 

An electronics board including wireless electronics and batteries is also present, embedded into the antenna substrate. The antenna exhibits a rather small value of C max> of about — lOdBi, due to the small dimensions and low conductivity of the textile material. However, measurements of the on-body link between two antenna prototypes worn on different body locations showed relatively high values of on-body channel gains, ranging between —47 and —56 dB in anechoic environment, and between —35 and —80 dB in a multipath scenario (hallway). Hence, the antenna represents a suitable small-sized and reliable solution for on-body wireless communication. 

The BPIX readout and control system consists of three main parts (see Sect. 7.3) the analog readout link between the modules and the FED, the digital control link between the modules and the pxFEC and the slow control link between the CCUs and the trFEC. At P5 the FED and FEC boards are installed in different VME crates in the CMS underground service room. Since one crate of electronic boards is controlled by one PC, the software used for communication is implemented as a distributed system. 

During numerous examinations, the failure data of over 40,000 electronic boards used in control systems of power plants have been collected and evaluated statistically [5-23], [5-24], [5-25]. As far as thermic stress was concerned, the environmental conditions with regard to thermic load on the structural elements were the same for all boards. The current was supplied by batteries which were recharged from the power network. The structural elements neither displayed overload conditions nor wear. 

Table 5.3 displays the determined failure data of the above-mentioned electronic boards. The statistical confidence area was determined with a degree of safety amounting to 95%. The majority of the failures was found in those electronic boards which were used in the input and monitoring areas of the control system. Boards of the input level are those electronic boards marked contact conversion in Table 5.3. At the monitoring level, the board types nonequivalence monitoring, signalling card, and display module" are used. The following failure statistics are examples of the types of failures found in boards from one manufacturer ...

The failure statistics consider 20 different operators or utilities. As a result of this experiment, it may be safely said that the majority of the boards had been destroyed as a consequence of careless test work and by external influences. Thus the board manufacturers have developed short-circuit-proof electronic boards to replace the old types. 

Figure 5.21 demonstrates the failure behavior of H),(K)0 electronic cards over a certain period of time. From this it becomes evident that the average monthly failure rate of these electronic boards will amount to 8-10. During the shutdown periods of the power plant, however, the failure rate jumps to 16-55. Hidden in these figures are, of course, boards which have failed at an earlier point in time that is, defective boards which had not yet been detected and were found during tests while the plant was shut down. Taking these uncertainty factors into consideration, the result will be a mean failure rate of lO Vh for any type of electronic board irrespective of its provenance or manufacture. 

Figure 5.21 Monthly number of failures from 10,000 electronic boards.

The following tabulation (Table 5.4) compares observed and—with the help of values obtained from the literature [5-26]—computed failure rates of electronic boards. The observed failure rates for the first four board types are greater than the computed ones since these boards are being used by first item lists at the input and monitoring levels and are subject to the aforementioned deterioration through external influence factors. However, this comparison of the failure rates still contains an uncertainty factor of... 

Table 5.4 Comparison of observed and computed failure rates in electronic boards...

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