Categories of Devices

Electrical switches, relays, and other devices are described for safety reasons by several general categories. Since these devices are potential sources of ignition during normal operation (for example, arcing contacts) or due to malfunction, the area classification limits the types of devices which can be used. 

High-temperature devices are defined as those devices that operate at a temperature exceeding 80 percent of the ignition temperature (expressed in Celsius) of the gas or vapor involved. The ignition temperature of natural gas usually is considered to be 900°F (482°C). Therefore, a device is 

Type Projected UsebI Life (Years) Projected Cycb Lite (Number of Cycles) Wet Shelf life (Months) Comments  

Primary 1-3 1 12 Least maintenance. Periodic replacement. Cannot be recharged. 

Lead Antimony 8-15 600-800 4 High hydrogen emission. Periodic equalizing is required for float service and full recharging. Low shock tolerance. Susceptible to damage from high temperature. 

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The first category of devices we ll discuss is multimedia devices. What is multi-media The simplest answer is multiple media. That is, it s a way of communicating information using more than one form, such as some combination of video, pictures, sound, and text. Several devices are included in the category, including CD-ROM drives, sound cards, speakers, and microphones. 

Any other records that the FDA requires to be maintained by regulation or by specific requirement for a particular device or category of devices... 

The examples of the second category of devices will be guided-wave optics, in which successive deposition of L-B films can be used to fabricate a waveguide or a composite waveguide. In principle, this method offers tremendous flexibility to fabricate many unusual waveguide structures. However, it is very difficult to maintain structural correlation and uniform layer-to-layer deposition for thousands of layers. Our experience has been... 

The biocompatibility testing protocol will depend on the category of device and duration of contact as described above. For chronically implantable materials, the entire range of ISO 10993-1 is recommended, as is summarized below. Please note that ISO 10993-1 is in the process of revision. It is recommended that the reader consult the revised version when it is available. Because of cost constraints, a stepwise evaluation is recommended. The decision to conduct the more costly phase 2 tests would depend on the results of the phase 1 tests. Again, the materials must be processed, cleaned, sterilized, and packaged in the same manner as the final product. Note that the following tests are listed and briefly described in ISO 10993-1, but detailed protocols are provided in other parts of the standard for most of these (ISO 10993-2 through 12). 

Categories of devices currently manufactured to exhibit these characteristics are discussed in this section. 

A fourth category of PV technologies, concentrator photovoltaics, uses small but very efficient cells Uluminated with concentrated sunlight. PV concentrators use lenses or reflective devices and track the sun through daUy cycles. The tracking maintains the concentrated light at intensities up to several hundred times normal sunlight. 

Cla.ss II Performance Sta.nda.rds. This category regulates devices for which General Controls are not sufficient to ensure safety and effectiveness. Class 11 controls iaclude all the controls ia Class 1. In addition, manufacturers of sutures ia Class 11 must give the EDA 90-days notice of their iatent to market the suture, by way of a 510(k) filing providing data to show that the suture is "substantially equivalent" to an already-approved device. Most sutures were reclassified iato Class 11 ia 1989. Other than USP standards, performance standards for sutures have not actually been promulgated, but the EDA has taken the stand that sufficient information exists ia the pubHshed Hterature to ensure the safety and effectiveness of sutures ia this class. 

With the passage of the Medical Device Amendments of 1976 (PubHc Law 94-295) Congress created a new category of color additive by mandating the separate listing of colorants for use in medical devices if the color additive in them comes in dkect contact with the body for a significant period of time. 

Air Filters The types of equipment previously described are intended primarily for the collection of process dusts, whereas air filters comprise a variety of filtration devices designed for the collec tion of particulate matter at low concentrations, usually atmospheric dust. The difference in the two categories of equipment is not in the principles of operation but in the adaptations required to deal with the dif-... 

Systematic error, as stated above, can be eliminated— not totally, but usually to a sufficient degree. This elimination process is called calibration. Calibration is simply a procedure where the result of measurement recorded by an instrument is compared with the measurement result of a standard. A standard is a measuring device intended to define, to represent physically, to conserve, or to reproduce the unit of measurement in order to transmit it to other measuring instruments by comparison. There are several categories of standards, but, simplifying a little, a standard is an instrument with a very high accuracy and can for that reason be... 

There are two categories of equipment which determine the selection of equipment general-purpose and special-to-type equipment. It should not be necessary to specify all the general-purpose equipment needed to perform basic measurements, which would be expected to be known by appropriately trained personnel. You should not need to tell an inspector or tester which micrometer, vernier caliper, voltmeter, or oscilloscope to use. These are the tools of the trade and they should select the tool which is capable of measuring the particular parameters with the accuracy and precision required. However, you will need to tell them which device to use if the measurement requires unusual equipment or the environmental conditions prevailing require that only equipment be selected that will operate in such an environment. In such cases the particular devices to be used should be specified in the test or inspection procedures. In order to demonstrate that you selected the appropriate device at some later date, you should consider recording the actual device used in the record of results. With mechanical devices this is not normally necessary because wear should be detected well in advance of there being a problem by periodic calibration. 

A special category of ignition system is the cartridge actuated device (CAD) also known as the Propellant Actuated Device (PAD) which serves to generate the mechanical force to close switches (in the manner of a squib) or to perform otherwise mechanical work (Vol 2, C70-R Ref 138, p 167)... 

Handbook of Chemical Vapor Deposition 2.2 Categories of Electronic Devices... 

The authors provide selection criteria, by which the suitability of a process for a distributed production can be assessed [139]. These are explicitly given for the categories of feedstock, processes, customer products, and waste products. This is completed by a list of suitable device types for distributed production such as plate heat exchangers, pressure and temperature swing units, electrostatic dispersers, and membrane units. The various operations often rely on the use of electricity and therefore are said to be particularly suited for operation at the mini scale. 

The Menschutkin reaction was carried out as a test reaction to show the feasibility of such novel micro flow concepts that allow to process fouling-sensitive reactions (see also Section 4.2.6 here another test reaction is decribed for the same purpose) [78]. The reaction of alkyl bromide with ternary bases such as pyridine or triethylamine gives quaternary salts insoluble in most solvents. Often, fairly rapid precipitation of this salt occurs, hence ideally serving as a test reaction for fouling sensitivity of micro-channel devices. The reaction of 4,4 -bipyridyl and ethyl bromoacetate [78] belongs to the category of fast-predpitating Menschutkin reactions, as the halide function is activated by the carbonyl fimction. 

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