Remote microwave

Waters J W 1993 Miorowave limb sounding Atmospheric Remote Sensing by Microwave Radiometry ed M A Janssen (New York Wiley) pp 383-496... 

Janssen M A (ed) 1993 Atmospheric Remote Sensing by Microwave Radiometry (New York Wiiey) The most oompiete guide to miorowave and THz atmospherio sensing. 

Microwave spectroscopy is used for studyiag free radicals and ia gas analysis (30). Much laboratory work has been devoted to molecules of astrophysical iaterest (31). The technique is highly sensitive 10 mole may suffice for a spectmm. At microwave resolution, frequencies are so specific that a single line can unambiguously identify a component of a gas mixture. Tabulations of microwave transitions are available (32,33). Remote atmospheric sensing (34) is illustrated by the analysis of trace CIO, O, HO2, HCN, and N2O at the part per trillion level ia the stratosphere, usiag a ground-based millimeter-wave superheterodyne receiver at 260—280 GH2 (35). 

A particularly difficult problem in microwave processing is the correct measurement of the reaction temperature during the irradiation phase. Classical temperature sensors (thermometers, thermocouples) will fail since they will couple with the electromagnetic field. Temperature measurement can be achieved either by means of an immersed temperature probe (fiber-optic or gas-balloon thermometer) or on the outer surface of the reaction vessels by means of a remote IR sensor. Due to the volumetric character of microwave heating, the surface temperature of the reaction vessel will not always reflect the actual temperature inside the vessel [7]. 

In the initial stages utilities ran wires, also known as hardwire or land lines, from the central computer (MTU) to the remote computers (RTUs). Since remote locations can be located hundreds of miles from the central location, utilities began to use public phone lines and modems, leased telephone company lines, and radio and microwave communication. More recently, they have also begun to use satellite links, the Internet, and newly developed wireless technologies. 

Any location that has a connection to the SCADA network is a target, especially unmanned or unguarded remote sites. Conduct a physical security survey and inventory access points at each facility that has a connection to the SCADA system. Identify and assess any source of information including remote telephone/ computer network/fiber optic cables that could be tapped radio and microwave links that are exploitable computer terminals that could be accessed and wireless local area network access points. Identify and eliminate single points of failure. The security of the site must be adequate to detect or prevent unauthorized access. Do not allow live network access points at remote, unguarded sites simply for convenience. 

Automation equipment at the metering sites generate production volume information, indicate alarm and other equipment status, and provide some control capability. This equipment is connected to remote terminal units (RTU) at optimum points within the field by individual wire pairs of buried cable. The RTU s store the information generated and, on request from the computer, transmit it to the computer center by means of microwave or wireline. RTU s also receive messages from the computer for transmittal to appropriate equipment for execution. 

Most DCS were, and still are, being sold to refineries and chemical plants where the distances involved and the environment do not require microwave communication. Responding to the market demand, few manufacturers were interested in developing the technique. Such systems that were available were, quite naturally, configured around the concept of closed loop control at the PCM level. Consequently, none of them could compete with the SCADA system in terms of numbers of data acquisition points. Alternatively, none of the SCADA system manufacturers could provide a sufficiently intelligent remote unit to execute closed loop control. 

Remote sensing in the far infrared and microwave spectral regions... 

The remote nature ofthe interaction between microwaves and the sample means that when the power is switched off the sample rapidly cools. Consequently, it is possible to use the microwave applicator in a more flexible fashion than a normal heating furnace. This becomes an important consideration in the economics of ceramics processing, since the ability to use the furnace flexibly for several processes combined with the shorter reaction times can lead to a more economic use of plant than the conventional thermal processing. 

Microwave energy can be introduced remotely, without contact between the source and the chemicals. 

Earlier methods for the determination of uranium in soils employed spectrophotometry of the chromophore produced with arsenic(III) at 655 nm [237 ] and neutron activation analysis [238]. More recently, laser fluorescence [239] and in situ laser ablation-inductively coupled plasma atomic emission spectrometry [240] have been employed to determine uranium in soil. D Silva et al. [241] compared the use of hydrogen chloride gas for the remote dissolution of uranium in soil with microwave digestion. 

Preparation and application of new spaceborne remote-sensing equipment to measure the water content in the troposphere and lower stratosphere. For example, the Microwave Limb Sounder (MLS) carried by the Aura satellite launched in 2004. 

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