A method for hermetically packing solid medicinal forms
Four basic methods are in existence for protecting solid drugs from external influences: i) coating of tablets with a film by pelleting or in a fluidized bed; 2) packaging preparations in polymeric film materials; 3) packaging in metal foil; 4) packaging in mixed films consisting of aluminum foil and cellophane, polypropylene, or other polymeric material. This method has the widest application at the present time. Methods have been developed not only for packaging in mixed films but also automatic lines of diverse productivity have been established.
EVALUATION OF POLYMERIC MATERIALS. I. SCREENING OF SELECTED POLYMERS AS FILM COATING AGENTS.
A procedure has been developed for the systematic evaluation of mechanical, thermal, and stability properties of polymeric materials through the study of unsupported films. Films of selected vinyl, acrylic, and cellulosic polymers were prepared by the knife edge applicator method and the mercury substrate technique. The mercury substrate technique afforded superior control of film thickness and facilitated film removal. Films that were very permeable to water vapor were rather impermeable to oxygen and vice versa. This relationship is discussed as it relates to a combination of the hydrophilic-lipophilic and pore theories of film structure. The unsupported vinyl films possessed superior mechanical properties of those tested. Moisture absorption by the polymer films was negligible. There was no discernible decomposition according to infrared analysis of the films, due to thermal, photo-oxidation, and/or aging effects.
Ignition and burning rates of segregated waste combustion in packed beds.
Recent developments in national recycling and re-use programmes for municipal waste have led to segregation of an increasing proportion of waste to enhance material recovery. Several of the segregated streams contain materials that can not viably be re-used or recycled but can be used for energy recovery. In this study, the combustion of cardboard and waste wood was investigated in a small-scale packed bed reactor in order to provide fundamental data for the design/operation of moving bed furnaces. Key parameters of combustion including the ignition and burning rates were evaluated for various air flowrates and compared to the modelling results. Two successive stages of combustion were identified for both samples: the propagation of ignition front into the bed and combustion of the fuel above the ignition front. The burning rate of cardboard reached a peak of about 300 kg/m(2)h at the air flowrate of 936 kg/m(2)h and decreased at higher air flowrates. For waste wood, both the ignition and burning rates increased in the tested range of the air flowrate up to 702 kg/m(2)h, of which the values were very close to those for the cardboard. The model prediction was in good agreement with the test results for waste wood. However, the burning rate for cardboard was under-predicted due to strongly irregular shapes of the fuel.