Furniture. Assessment of surface resistance to dry heat

1997 ◽  
Keyword(s):  
Surface Resistance ◽  
Dry Heat

Effects of sterilization modes on the mechanical strengths of plaster of paris implants

1989 ◽  
Vol 47 ◽  
pp. 890-891
Author(s):  
K. Cowden ◽  
B. Giammara ◽  
T. Devine ◽  
J. Hanker
Keyword(s):  
Gamma Radiation ◽  
Calcium Sulfate ◽  
Significant Loss ◽  
Potassium Sulfate ◽  
Limiting Factors ◽  
Radiation Sterilization ◽  
Plaster Of Paris ◽  
Hardness Tester ◽  
Dry Heat ◽  
Calcium Sulfate Hemihydrate

Plaster of Paris (calcium sulfate hemihydrate, CaSO4. ½ H2O) has been used as a biomedical implant material since 1892. One of the primary limiting factors of these implants is their mechanical properties. These materials have low compressive and tensile strengths when compared to normal bone. These are important limiting factors where large biomechanical forces exist. Previous work has suggested that sterilization techniques could affect the implant’s strength. A study of plaster of Paris implant mechanical and physical properties to find optimum sterilization techniques therefore, could lead to a significant increase in their application and promise for future use as hard tissue prosthetic materials.USG Medical Grade Calcium Sulfate Hemihydrate Types A, A-1 and B, were sterilized by dry heat and by gamma radiation. Types A and B were additionally sterilized with and without the setting agent potassium sulfate (K2SO4). The plaster mixtures were then moistened with a minimum amount of water and formed into disks (.339 in. diameter x .053 in. deep) in polyethylene molds with a microspatula. After drying, the disks were fractured with a Stokes Hardness Tester. The compressive strengths of the disks were obtained directly from the hardness tester. Values for the maximum tensile strengths σo were then calculated: where (P = applied compression, D = disk diameter, and t = disk thickness). Plaster disks (types A and B) that contained no setting agent showed a significant loss in strength with either dry heat or gamma radiation sterilization. Those that contained potassium sulfate (K2SO4) did not show a significant loss in strength with either sterilization technique. In all comparisons (with and without K2SO4 and with either dry heat or gamma radiation sterilization) the type B plaster had higher compressive and tensile strengths than that of the type A plaster. The type A-1 plaster however, which is specially modified for accelerated setting, was comparable to that of type B with K2SO4 in both compressive and tensile strength (Table 1).

THE ROLE OF SURFACE RESISTANCE IN FLUIDIZED BED HEAT TRANSFER

1994 ◽  
Author(s):  
Leon R. Glicksman ◽  
M. Hyre ◽  
M.C. Lints ◽  
N. Decker
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Surface Resistance

RESEARCH: Dry Heat Processing of Single-Use Respirators and Surgical Masks

2020 ◽  
Vol 54 (6) ◽  
pp. 410-416
Author(s):  
Joyce M. Hansen ◽  
Scott Weiss ◽  
Terra A. Kremer ◽  
Myrelis Aguilar ◽  
Gerald McDonnell
Keyword(s):  
Microbial Contamination ◽  
Healthcare Providers ◽  
High Volume ◽  
Airborne Particles ◽  
Heat Processing ◽  
Protective Equipment ◽  
Healthcare Facilities ◽  
Dry Heat ◽  
Surgical Masks ◽  
Single Use

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2, has challenged healthcare providers in maintaining the supply of critical personal protective equipment, including single-use respirators and surgical masks. Single-use respirators and surgical masks can reduce risks from the inhalation of airborne particles and microbial contamination. The recent high-volume demand for single-use respirators and surgical masks has resulted in many healthcare facilities considering processing to address critical shortages. The dry heat process of 80°C (176°F) for two hours (120 min) has been confirmed to be an appropriate method for single-use respirator and surgical mask processing.

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