S Your new gas furnace may have been installed in one of two. ways, as a direct-vent (2-pipe-Fig. 2) application or as a. non-direct vent (1-pipe-Fig. 3) application. S In a direct-vent (2-pipe) application,your furnace uses air. from outside the home for combustion and ventsflue gas to the. outdoors.
For the biological concept, see Anti-predator adaptation. A defence mechanism is an unconscious psychological mechanism that reduces anxiety arising from unacceptable or potentially harmful stimuli. Sigmund Freud was one of the first proponents of this construct.
Nuclear, biological and chemical (NBC) disposal technicians taking part in a training exercise. Chemical, biological, radiological and nuclear defense (CBRN defense or CBRNE defense) is protective measures taken in situations in which chemical, biological, radiological or nuclear warfare (including terrorism) hazards may be present. CBRN defense consists of CBRN passive protection, contamination avoidance and CBRN mitigation.