Dog’s nose

The most celebrated mammalian olfactory detector is the dog s nose. As a predator, the dog locates its prey by air scenting (following a gradient of airborne odors) and tracking. Practitioners are familiar with the extreme olfactory sensitivity of the dog. The detection threshold for butyric acid has been determined as 9 x 10 molecules/cm air (Neuhaus, 1953). Considering that... 

The underwater sensor platform is derived from the Fido explosives vapor sensor, originally developed under the Defense Advanced Research Projects Agency (DARPA) Dog s Nose Program. The vapor sensor, whose operation is discussed in Chapters 7 and 9 and in other publications [7-9], was developed for the task of landmine detection. The underwater adaptation of the sensor is very similar to the vapor sensor. In the underwater implementation of the sensor, thin films of polymers are deposited onto glass or sapphire substrates. The emission intensity of these films is monitored as water (rather than air) flows past the substrate. If the concentration of TNT in the water beings to rise, the polymer will exhibit a measurable reduction in fluorescence intensity. The reduction in emission intensity is proportional to the concentration of target analyte in the water. Because the sensor is small, lightweight, and consumes little power, it proved to be ideal for deployment on autonomous platforms. 

When one looks at studies on how the dog s nose moves the dust particles [1] to the smell sensors with his nose hairs and mucus, then one realizes that the water in the mucus dissolves the TNT off the dust and offers it to the olfactory sensors. Fjellanger also quoted literature of how a dog s nose uses side muscles to pulse air at a frequency of 3 to 5 puffs per second at the slits on the side of his nostrils when sniffing. The dog then sucks the stirred up dust with a long... 

This volume can best be understood by considering the olfactory senses of animals. Everyone has witnessed the ability of a dog to use its nose with its superb olfactory sense to detect trace odors. A holy grail of detection science has been to duplicate a dog s nose electronically. Dr. Woodfin s volume tries to assess where the scientific community stands in its search for this holy grail. The authors of this volume are using this chemical sensing approach to detect explosives. Explosives, as used in this context, are defined as materials that concentrate releasable energy controllable or uncontrollable. 

The cat leaves a trail of molecules across the yard. These molecules leave the ground and mix with the air, where they enter the dog s nose, activating the sense of smell. 

Given the increased awareness of possible terrorist incidents, this is obviously important. Scientists are working hard to develop chemical and electronic devices that are as sensitive as a dog s nose, but at the moment dogs are superior at detecting explosives. Although volatiles associated with the plastic casings of landmines can be detected, normally it is the explosive they are looking for. It s been... 

The dog ma.sk is somewhat similar to the horse mask, except tlial it vcrs both jaw.s as well as the nostrils, since a dog breathes through iKith nose and mouth. A.s dog.s are not used in the American Army, dog masks are nut authorized. 

Or in other more bizarre ways. A 23-year-old medical student saw his dog (a puppy) suddenly collapse. He started external cardiac massage and a mouth-to-nose ventilation effort. Moments later the dog died, and the student felt nauseated, vomited and lost consciousness. On the victim s arrival at hospital, an alert medical officer detected a bitter almonds odour on his breath and administered the accepted treatment for cyanide poisoning after which he recovered. It turned out that the dog had accidentally swallowed cyanide, and the poison eliminated through the limgs had been inhaled by the master during the mouth-to-nose resuscitation. Journal of the American Medical Association 1983 249 353. 

Moulton (1977) used operant conditioning to determine the minimum detectable thresholds of dogs for several odors. Dogs were first trained to insert their noses into an airstream to obtain water as positive reinforcement. Next, odorant was added to the airstream as a response contingency, that is reinforcement was presented only in the presence of the odor. Incorrect responses were punished with time-outs (i.e., the test was interrupted for a period of time). Stimuli concentrations were successively lowered until the subject s performance dropped to a level of chance. 

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