Human sense of smell

Odour measurement by chemical analysis of the odorous compounds presents also a number of limitations. As will be shown further on, it is a difficult analysis, which is essentially due to the great sensitivity and specificity of the human sense of smell. But... 

Flavour is a complex sensation, made up principally of smell and taste, but touch and hearing contribute as well. The human senses of smell and taste differ in sensitivity, between each other and depending on the nature of the component eliciting the sensation. Substances may have no impact at all (such as oxygen or carbon monoxide) or exhibit very low thresholds (such as 2 X 10 14g mL 1 water for the odour of bis-2-methyl-3-furyl disulfide).204 In general, odour thresholds are much lower than taste thresholds and so flavour tends to be dominated by odorous components, by substances able to reach the olfactory epithelium high up in the nose, that is, substances with at least some volatility. Hence, the emphasis on the volatile compounds derived from the Maillard reaction. 

Q8. (-)-Carvone (73) occurs in spearmint and its enantiomer (+)-carvone (74) is found in caraway seed. To the human sense of smell, these two enantiomers have different odours. Where is the stereogenic centre in 73 and in 74 What conclusions can be drawn about the human olfactory receptor site ... 

Humans sense of smell, or olfaction (from the Latin, olere, to smell + facere, to make), is highly developed. We can recognize approximately 10,000 scents, including mer-captans (disagreeable-smelling compounds contained in skunk spray), which we can detect at a concentration of one part per billion. 

Focus on producing pressure sensors with an operating temperature of up to 225°C Semiconductor gas sensors aiming to realize a gas detection system, which is equivalent to or superior to a human sense of smell Sensing elements, devices, instruments, and systems that enable our customers to monitor, protect, control, and validate their critical processes and apphcations Hazard detection and life protection... 

Shepherd GM (2004) The human sense of smell are we better than we think PLoS Biol 2(5) el46. doi 10.1371/journal.pbio.0020146... 

NOTE LNG liquid and vaporized gas Is odorless and undetectable by the human sense of smell. Frost buildup Is not necessarily evidence of leakage. Many components of LNG fuel systems are extremely cold and will exhibit an even coat of frost produced by moisture In the surrounding air condensing and freezing on them. 

So, we can use our powerful human sense of smell to guide us to the source of possible faults. Conductor insulation blackens when it becomes very hot and becomes brittle and stiff. Once more, we can use the human senses of sight and touch to detect these faults when carrying out an internal inspection of socket outlets, switches and luminaries. 

RL Doty. Psychophysical measurement of odor perception in humans. In DG Laing, RL Doty, W Breipohl, eds. The Human Sense of Smell. Berlin Springer-Verlag, 1991, pp 95-151. 

For various reasons, reliable electronic-nose applications have been slower to develop. Chapter 13 discusses the benefits of MS as a potential e-nose sensor. This book also discusses the value of time-of-flight MS to the study of flavors and odors. Incorporating the human sense of smell with potent analytical systems is invaluable in problem solving. Just as sample preparation procedures and analytical instrumentation have continued to evolve and improve, so have olfactometry techniques. Chapters 11 and 12 cover various olfactometry techniques, including a new, easier-to-implement method called SNIP. 

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