ined the operational diff erences when silica sand is used in metalcasting facilities that historically have used olivine sand.
Conclusions
• As silica sand use is increased over olivine sand (Fig. 1), less moisture is required to develop the desired compactibility. The density, flowabil- ity, cone jolt toughness, dry compres- sion strength and hot compression strength of the prepared green sand mixture decrease, and wet tensile strength (while less impacted than other characteristics), permeability and friability increase.
amount of adhering sand and require more finishing.
Presentation
Antimicrobial Copper: Clinical Performance Against Bacteria T at Cause Infections and Impact on Hospital Patients (12-113)
Authors
James Michel, Harold Michels, Wilton Moran, Adam Estelle and Kyle Sexton, Copper Development Association, New York; Michael Schmidt, Medical Univ. of South Carolina, Charleston, S.C.
• Silica sand produces aluminum cast- ings of equal or higher quality than those produced in olivine sand.
• Aluminum castings produced from silica sand molds may have a higher
Background Cast and wrought copper alloys are
intrinsically antimicrobial materials. An extensive body of laboratory research has proven their ability to kill more than 99.9% of a wide range of pathogens within
two hours. T e contribution of bacterial touch surface contamination to hospital- acquired infections (HAI) has not been well defi ned. T is study was conducted to assess whether a lower environmental bio- burden on critical touch surfaces would result in a lower risk of contracting an infection while hospitalized.
Conclusions
• The relative risk of contracting an HAI for patients in rooms with copper objects was reduced by more than 40% compared to patients in rooms with standard objects.
• Copper reduced the microbial burden on surfaces by 98%. The findings suggest environment plays a substantial role in the contraction of HAIs.
• Through the introduction of continu- ously active antimicrobial surfaces in
Fig. 1. Silica sand from Roff, Okla. (top), and Oregon, Ill. (center), were compared with olivine sand for the purposes of this experiment.
May 2012 MODERN CASTING | 53
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