Chemical detection events

A defensive strategy against chemical/biological attacks that does not rely on a detection event to initiate a response... 

Detect—a security strategy to identify a perpetrator attempting to commit a chemical security event or other criminal activity in order to provide real-time observation as well as postincident analysis of the activities and identity of the perpetrator. 

A positive simple chemical lest is indicated by one or more detectable events, such as a change in color, formation of a precipitate, evolution of a gas, uptake of a gas. evolution of heat. 

The reproducibility of an effect requires the ability to exploit a specimen s causal properties. Again, for both an absorption spectrometer and a Raman spectrometer, a signal is produced from a complex system in which a specimen reacts to instrumental agitations. Such a reaction is caused by an internal change of the compound s dynamic state. As a specimen in laboratory research, a chemical compound is characterized by its capacities for change. A specimen is known by its tendencies to permit interference from radiation and to react to certain manipulations, leading to the causal production of instrumentally detectable events. In Raman spectroscopy, for example, a specimen is a system of causal properties, which, under appropriate laboratory conditions, produce an inelastic scattering of radiation, known as the Raman effect. 

The distinction between chemical sensors and biosensors is more complex. Many authors attempt to define a sensor based on the nature of the analyte detected. This approach can be misleading since nearly all analytes measured by a chemical or biosensor are chemicals or Wochemicals, the exception being sensors which detect whole cells. Other authors attempt to define a chemical of biosensor by the nature of the reaction which leads to the detection event. Again, this is confusing since all reactions at chemical and biosensor surfaces are chemical (or biochemical) reactions. 

A chemical or biological sensor is a measurement device which utilizes chemical or biological reactions to detect and quantify a specific analyte or event. The device is self-contained and comprised of three basic components (i) a chemically or biologically active surface which specifically interacts with the analyte to be measured (ii) a transducer which detects the chemical/biochemical event occurring between the... 

Detection— a countermeasnre strategy intended to identify an adversary attempting to plan or commit a chemical secmity event or other criminal activity via either real-time observations or pre-incident analysis of the activities/intelligence... 

Nanomaterials, such as carbon nanotubes and semiconductor or polymer nanowires, can be functionalized with appropriate chemical or biological capture probes [3, 4], A unique property of these materials is flie very high surface-to-volume ratio. The chemical binding event on their surface causes a change of the crmductance of the nanotube or nanowire and thus can be identified via electrical measurement. Electrical nanobiosensors are capable of realizing sensitive, label-free, and real-time detection of a wide range chemical and biological species. 

The ability to detect molecnle-receptor binding events is a critical aspect for chemical detection methods based on molecular recognition. Currently, fluorescence is a primary means by which these events are detected. (4-6) However, this often requires modification of the receptor to incorporate the fluorescent center and/or immobilization of the receptor molecule onto a surface. Far more desirable would be a means to directly detect the molecule-receptor interaction in solution without the need to modify the naturally occurring receptor. In the absence of any receptor modification, however, there are no signatures stemming from the molecule-receptor interaction that are... 

Other approaches to chemical detection systems concentrate on the transduction of the binding event, highlighting the sensitivity. In this case, the function of the material is to report the interaction of the sensor with the target. Photoluminescence, for example, is a desirable property because changes in the emitted light can be manipulated by materials development to indicate the interaction of the target with the recognition site. 

The system architecture utlized within the chemical detection, warning and reporting system installed at APG s CAS Y is based upon a simple star topology, consisting of a central hub with a suite of remote distributed processing nodes (see fig 1). The central hub contains the CPIMS as well as several components of the response subsystem. The equipment located within the central hub consists primarily of a telemetry interface and a central computer with display. All of this hardware is then tied into an uninteruptable power supply to support critical operations in the event of power loss. The central hub is usually located in a central operations or emergency response center. 

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