Accelerated aging in combined stress environments. [Synergistic effects of thermal and radiation environments on Bacillus subtilis]

Conference · Sat Jan 01 04:00:00 EST 1977

OSTI ID:7316478

Gillen, K. T.

Accelerated aging can be useful in estimating the lifetime of a component of interest. If under ambient conditions a single environmental variable is the predominant cause of the aging process, accelerated aging is often accomplished by raising the level of this variable above its ambient value. The relationship between the mean time to failure and the value of the accelerated environmental variable is extrapolated to ambient conditions in order to establish the ambient lifetime of the component. Often, however, the ambient deterioration of a component is due to a combination of two or more environmental stresses. Synergism is sometimes important in such cases so that the deteriorating effects of the various environments are not additive. Because of possible complications caused by synergistic effects, no general method currently exists for carrying out accelerated aging in combined environments. The present paper proposes a general phenomenological model potentially applicable to combined environmental situations. The model is applied to literature data on the thermoradiation sterilization of Bacillus subtilis var niger for which significant synergistic effects were found for combined thermal and radiation environments. The proposed model does an excellent job in predicting the experimental data.

• Research Organization: Sandia Labs., Albuquerque, NM (USA)
• DOE Contract Number: EY-76-C-04-0789
• OSTI ID: 7316478
• Report Number(s): SAND-77-0511C; CONF-771010-2
• Country of Publication: United States
• Language: English

Related Subjects

560131* -- Radiation Effects on Microorganisms-- Basic Studies-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACILLUS
BACILLUS SUBTILIS
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL STRESS
ENVIRONMENT
GAMMA SOURCES
LIFE SPAN
MICROORGANISMS
RADIATION EFFECTS
RADIATION SOURCES
SYNERGISM
TEMPERATURE EFFECTS
TIME DEPENDENCE