A new microencapsulation method using an ultrasonic atomizer based on interfacial solvent exchange

Abstract: Reservoir-type microcapsules were produced in a mild and highly efficient manner using a coaxial ultrasonic atomizer. To understand the microencapsulation mechanism, the atomizer was operated in different modes. The results suggested the reservoir-type microcapsules were formed by midair collision of the microdrops of the two component liquids consisting of a polymer solution and an aqueous solution. The encapsulation efficiency and the distribution of the microdrops captured in midair were dependent on the ratio of the flow rates of the two liquids, which suggested that the collision involved multiple microdrops. This method allowed lysozyme to be encapsulated without loss of functional integrity and to be released with near zero-order kinetics for over 50 days. The ultrasonic atomizer provided a new method of preparing reservoir-type microcapsules. © 2004 Elsevier B.V. All rights reserved.

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Coating Drug-eluting Arterial Stents Using Ultrasonic Spray Nozzles

Abstract: One proven method used to treat clogged arteries employs tubular, mesh-like metal structures, known as stents, inserted into an affected artery to relieve the blockage. Bare metal stents often cause a condition called restinosis, the buildup of scar tissue around the stent, causing re-blockage. To counter this, polymer coatings containing drugs that are released over time are used to inhibit restinosis. Applying coatings to stents, which have intricate geometries, is challenging. Using ultrasonic atomizing spray nozzles has proven effective in achieving continuous and uniform coatings. This paper describes the unique nozzle designs employed, the methodology used, and the results obtained...

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ATMOSPHERIC PRESSURE LIQUID DEPOSITION – A NEW ROUTE TO HIGH PERFORMANCE COATINGS

Abstract: Plasma enhanced coating processes are well known as a route to well adhered, conformal, high performance coatings. These processes deliver industrial coatings without the need for solvent, surfactant and drying ovens. However, application has often been restricted to high value opportunities as plasma processes typical operate at reduced pressure, with high capital cost and batch wise operation. By combining Atmospheric Pressure Glow Discharge (APGD) technology with a unique precursor delivery system Dow Corning Plasma has developed a new coatings approach – Atmospheric Pressure Liquid Deposition...

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NOVEL USES OF TiO2 IN CRYSTALLINE SILICON SOLAR CELLS

Abstract: Novel applications for titanium dioxide (TiO2) thin films have the potential to reduce production costs of silicon (Si) solar cells, especially for structures like the buriedcontact solar cell. This paper demonstrates several new uses for TiO2 films. Firstly, it is demonstrated that the TiO2 film does not contaminate the silicon wafer or furnace after lengthy high-temperature processing. Secondly, a thin silicon dioxide passivation layer can be grown at the TiO2/Si interface by performing a brief oxidation after the deposition of the TiO2. With this method, very low emitter dark saturation currents have been achieved on lightly-diffused high-resistivity float zone wafers. Thirdly, TiO2 films doped with 1% phosphorus were investigated as an emitter dopant source. Initial results have shown that light diffusions are possible. Finally, the applicability of TiO2 as a phosphorus diffusion barrier was investigated.

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UNIVERSAL SIZE - DISTRIBUTION AEROSOL GENERATOR

Abstract: A variety of aerosol generators have been developed to produce aerosol particles with different size distribution. Most of these aerosol generators can only be modified to produce aerosol particles of different count median diameter with about the same geometric standard deviation. No generator is specifically developed to produce particles having the same count median diameter but with different geometric standard deviation, which may be critical to some aerosol characteristics, such as optical and filter loading properties. Two computer-controlled peristaltic pumps were used to carry sodium chloride solution and water into a 60 kHz ultrasonic aerosol atomizing nozzle.

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AEROSOL WIND TUNNEL SYSTEM

Abstract: The Environmental Protection Agency (EPA) plans to acquire a large, state-of-the-art Aerosol Wind Tunnel System (AWTS) for the production, measurement, and evaluation of aerosols, with the larger purpose of determining the exposure, effects, and risks of aerosols in the ambient air on people and the environment. The AWTS is to be a highly specialized wind-tunnel system with very wide ranges of flow speeds, particle sizes, and aerosol loadings, and with controlled air temperature and relative humidity. The system will require automated controls and integrated measurement capabilities for measuring, monitoring, and regulating conditions in the tunnel.

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CARBON PROFILE OF RESIDENTIAL INDOOR AND IN THE SUBTROPICAL REGION

Abstract: Carbon profiles of PM1 and PM2.5 were measured simultaneously in the indoor and outdoor air of 10 homes in the Taipei urban area in both summer and winter seasons.

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HIGH RELIABILITY, AUTOMATED FIBER RECOAT PROCESS THAT INCREASES FIBER RECOATING YIELDS

Abstract: From restructuring of the telecommunications market, accelerated reduction of component pricing has emerged. High yield manufacturing practices are an important factor to support price reduction while insuring high quality throughput. Improvements in Bragg grating manufacturing have been realized through the development of a novel semi-batch automation process. Although the entire process of fiber handling, from spooling through final packaging is unique, in the interest of time we will focus on our fiber coating reinstatement technique.

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PROCESS EFFECTS ON THE PROPERTIES OF SPRAY-FREEZE-DRIED POWDERS

Abstract: As former investigations have shown, spray-freeze-drying can be used as a method for the preparation of dry powders suitable for various applications. To study the mechanism of particle formation during this process, solutions of two well-known excipients, trehalose and mannitol, were spray-freeze-dried and the resulting powders were characterized. Both substances may be suitable for later use in formulations containing pharma-ceutical proteins.

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NANOCRYSTALLINE BATIO3 FROM FREEZE-DRIED NITRATE SOLUTIONS

Abstract: An aqueous, all nitrate, solution-based preparation of BaTiO3 is reported here. Rapid freezing of a barium and titanyl nitrate solution, followed by low temperature sublimitation of the solvent, yielded a freeze-dried nitrate precursor which was thermally processed to produce BaTiO3. XRD revealed that 10 min at temperatures >600 ±C resulted in the formation of phase pure nanocrystalline BaTiO3. TEM revealed that the material was uniform and nanocrystalline (10 –15 nm). The high surface to volume ratio inherent in these small particles stabilized the cubic phase of BaTiO3 at room temperature.

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TRANSPARENT CONDUCTORS AND BARRIER LAYERS FOR THIN FILM SOLAR CELLS

Abstract: This research was undertaken to increase the efficiency of thin-film solar cells based on amorphous silicon in the so-called superstrate structure (glass front surface/transparent electrically conductive oxide (TCO)/pin amorphous silicon/metal back electrode). The TCO layer has to meet many requirements: high optical transparency in the wavelength region from about 350 nm to 900 nm, low electrical sheet resistance, stability during handling and deposition of the subsequent layers and during use, a textured (rough) surface to enhance optical absorption of red and near-infrared light, and low-resistance electrical contact to the amorphous silicon p-layer. Fluorine-doped tin oxide 3 has been the TCO used in most commercial superstrate amorphous silicon cells.

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A BETTER WAY TO PRODUCE THIN-FILMED PROTOTYPES

Abstract: Rapid prototyping is essential to fast-paced, results-oriented development programs. A new ultrasonic direct-injected, pulsed-CVD system gives designers a robust, versatile, and cost-effective tool for producing prototype devices requiring thin films. The system can be used to make films from metal-organic compounds, polymers, ceramics, and nanophase suspensions. The system called ThinSonic uses In situ process controls which lets designers create a variety of structures including MEMS (microelectrical ma-chine system), organic light-emitting diodes (OLEDs), conformal coatings, thermal barriers, surface acoustic-wave (SAW) chemical sensors, touch screens, and many other thin film circuits and devices.

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THE DAWN OF A NEW AGE IN COATING TECHNOLOGY

Abstract: Always in the forefront when it comes to coating science, Rexam Custom once again surges forward, this time to bring thin-film coating technology to a new plateau. It's lonely at the top, but it's usually a nice place to be. For the last two decades, Rexam Custom, Matthews, NC, has frequently found itself in the good company of only a few others like itself-organizations that specialize in coating technologies. With the recent installation of a new thin-film lab coater, Rexam Custom believes it will distance itself from competitors in a manner that will be difficult to duplicate.

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