Interfacing devices

RAC publications include data summaries for specific component types, such as hybrid microcircuits, small, medium and large-scale integration digital devices, linear and interface devices, digital monolithic devices, and discrete semiconductors. In addition, there are reliability and equipment maintenance data books that provide the failure and repair time data on military electronic equipment by application such as subsystem. 

This arrangement is also shown in Fig 5). Under these conditions the GC-CI system is quite simple and does not require an interfacing device to eliminate the carrier gas... 

A 10 pi volume of the aldehyde was placed in three reservoirs and 10 pi of the 1,3-diketone in three other reservoirs [18]. The chip was inserted into the interfacing device and a script for defining pressures was set in the multiport control using a Caliper 42 Workstation . A 30 min run was carried out. An eight-peristaltic pump system was used as pressure or vacuum source. N o active quenching was performed, but it was assumed that by dilution in the collection reservoir reaction was stopped or at least notably slowed. 

Apparatus. Since all the polymer modification reactions presented in this paper involved gas consumption, an automated gas consumption measuring system was designed, fabricated and used to keep constant pressure and record continuously the consumption of gas in a batch type laboratory scale reactor. Process control, data acquisition, and analysis was carried out using a personal computer (IBM) and an interface device (Lab-master, Tecmar Inc.). 

Figure 1 Schematics of the electron diffractometer + precession interface device adapted to a TEM. Diffractometer can be adapted either below the camera plates, or in the 35mm port.

Fig. 1. Electronic medication event monitor in the process of communicating stored data from monitor to computer. The transfer occurs without wire connection between the inverted monitor and the communications interface device, which transfers data to MS-DOS-based computers via serial port. A second medication event monitor, with a somewhat larger container size, stands nearby. (Copyright, 1994, APREX Corporation reproduced with permission.)...

The modular backbone introduced here allows both commercial and demonstration-type micro structured devices to be coupled in all three dimensions in a flexible and easy manner. Micro structured heat exchangers, reactors and mixers of different manufacturers are surface mounted on this backbone. Owing to the standardized interfaces, devices can easily be exchanged, for example, to evaluate different types of mixers. The backbone itself consists of elements which can be combined individually and flexibly in all directions, according to the demands of the plant to be built. The backbone provides the flow paths for fluids and electrical conduits for power supply and signal transmission of sensors and actuators. 

The generation of frequency sweeps under computer control, described in Section II, 3 (p. 13) is one small aspect of a general tendency towards control of analytical instrumentation by means of digital computers, through appropriate interfacing devices. Several commercial and individually built systems have appeared in which all of the instrumental parameters for frequency sweeps or pulse-excitation (see Section IV, p. 45) are selected by teletype or numerical keyboard input to the computer, which then acquires the spectral data automatically and performs any further processing required. Automatic analysis of spectral peak positions and areas by a computer, and printing of the numerical results on a teletype or... 

Step four in the interfacing operation is the use of computer software to communicate with a device and to capture the information it sends for analysis and display. This can be done at a basic level using machine language or higher programming tools such as Visual Basic, but increasingly this capability is provided by manufacturers of instraments, measurement systems, or interface boards. This relieves the user of much of the effort in interfacing devices and allows efficient and easy set up of different experiments typically done in physical chemistry laboratories. As illustration, we consider two examples of measurement approaches that can be used in a number of the experiments in this book. 

An important additional feature of Cl spectroscopy is its abUity to handle gas chromatographic (GC) effluents directly if a proper reagent gas is used as the carrier gas in the GC. (This arrangement is also shown in Fig 5). Under these conditions the GC-Cl system is quite simple and does not require an interfacing device to eliminate the carrier gas... 

An automatic control system consists of various pressure, temperature, and flow sensors, valves and components controlled by a programmable logic controller (PLC), and an operator interface device. The operator interface control device can be as simple as a stop-go for totally dedicated systems, or a personal computer. A personal computer connected to the PLC to provide operator interface, data collection and analysis capability is recommended especially if the system parameter and/or the parts being processed will be changing. More importantly, a computer control system assures consistent and repeatable operation. 

A distributed control system is a system that is functionally integrated but consists of subsystems that may be physically separate and remotely located from one another. A shared display is an operator interface device such as a computer screen or video screen that is used to display process control information from a number of sources at the command of the operator. Most plants built since 1990 (and many older plants) use shared displays instead of instrument panels. 

Products/technologies These include Perfusion Chromatography technology advanced workstations, chemistry and other tools for the biotechnology industry robotics interface device for preparing biological samples for analy-... 

The standard for a modem vehicle requires it to start within 2 seconds at worst. A fuel cell starts well within 1 second. However, fuel cells, including hydrogen fuel cells, do not operate well at subfreezing temperatures. This is because fuel cells are basically a liquid interface device and need liquid-phase water to operate. Running the system under the conditions of a highway environment is possible, but the current cost is too great for commercialization. 

One important aspect which should he pointed out is that there is a basic incompatibihty between GC and MSD, the mass spectrometer operate at pressures of 10- torr or less, whereas the gas chromatograph effluent operates at about 760 torr. An interface device is necessary to handle the pressure differences. The simplest and most efficient interface in GC/MSD is a direct capillary column interface. The low flow rate of the narrow bore column and the high pumping rate of an oil diffusion pump backed by a suitable direct drive mechanical pump assure pressures less than lO " torr and allow for the direct insertion of the colmnn end into the mass spectrometer. Interfacing megabore... 

The multiplexer function involves a device that is under the immediate control of the computer and returns to the computer a reading of the current condition of each item being monitored. It also transmits control commands from the software operating the reactor. These requirements are not automatically available in all interface devices nor are they available in every control software package. Care must therefore be taken in the first instance in selecting a control and data logging package that allows two-way communication with all the components of the equipment. 

Brossa et al. developed an automated SPE-GC-MS method for the determination of endocrine disrupting compounds including six phthalate esters. The interface device was a programmed temperature vaporizer (PTV), whose liner was packed with Tenax. The samples were spiked with 50% of methanol and 15 ml of this mixture were preconcentrated. Before elution, the precolumn was dried with nitrogen. The analytes were desorbed in the backflush mode with three ethyl acetate fractions of 100 /rl and online transferred to the GC system. The performance of the method was tested with several environmental water samples. The recoveries achieved were satisfactory and the detection limits were between 1 to 36 ng/1. 

The concept of thermal desorption modulation (TDM) finally found its own specific area of application as the essential interface device between the two columns of a comprehensive two-dimensional separation system [28]. The TDM device consisted of a short section of a column that could be rapidly and reproducibly heated by an electrical current passing through an electrically conductive film. The authors used a segment of a capillary column with a narrow film thickness, covered with a layer of electrically conductive paint as the modulating interface between the two columns (Figure 8). Substances retained on the stationary phase of this modulator section were pulsed into the second column by resistive heating. 

The GageTalker Corporation (formerly Observational Systems) markets the OS-3 Plus Event Recorder. This versatQe recorder is useful for setting and updating standard times, machine downtime studies, and work sampling. The device allows the analyst to select the time units appropriate for the study—0.001 min, 0.0001 hr, or 0.1 sec. The total time, frequency, mean times, performance ratings, normal times, allowances, standard times, and pieces per hour may be printed through printer interface devices. In addition, the standard deviation, the maximum and minimum element values and frequencies are also available. 

Mtike someone responsible for operating and maintaining eneigy systems in the faciUty. Check ownership of interface devices with the utility supplier. 

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