Fabrication techniques gases

In addition to the materials costs associated with a given fabrication technique, the cost of the equipment needed to fabricate the cell and the operating costs of the equipment—electricity, natural gas for firing kilns, etc.—and other process costs of the... 

Recently, the planar structures using bipolar current collection have received more consideration for SOFCs because of new gas sealing and fabrication techniques. 

F. Y. Zhang, A. K. Prasad, and S. G. Advani. Investigation of a copper etching technique to fabricate metallic gas diffusion media. Journal of Micromechanics and Microengineering 16 (2006) N23-N27. 

Under G. E. Spangler, Technispan has used micro-electromechanical systems fabrication techniques to develop miniaturized gas chromatography systems for integration with IMS systems (such as the CAM or AC AD A). DARPA has provided funding, although no complete system has been produced. Many classical laboratory techniques are being pursued in the MEMS arena, but so far only pieces of devices have been produced. 

Whereas all conventional thermoplastic fabrication techniques have been successfully employed to convert pellets of HIPS into useful articles, extrusion (film, sheet, profile and multi-layer) and injection molding (solid, structural foam and gas-assist) are the predominant processing technologies. Innovative hardware technologies, in both extrusion and injection molding, have provided means to combine less expensive materials, such as polystyrene, with polymers or structures offering key performance characteristics. 

Recent advances in microelectronic fabrication techniques, in development of modified electrode surfaces and ion-selective membranes, and in availability of new materials give promise for development of new electrochemical sensors. For both gas and liquid sensors, the possibility of much higher sensitivity exists. Lower detection limits are possible for environmental, clinical, and general analysis situations. Sensors developed to date are primarily based on classical and relatively unsophisticated approaches. With newer methodologies and device designs, one may anticipate at least a ten-fold improvement in detection limits. 

The free floating film is transferred to a microporous support by bringing a sheet of the support into contact with the underside of the ultrathin film, lifting it from the water surface.9 Also, two layers can be simultaneously cast and laminated to a carrier web.7 8 Numerous patents have appeared in recent years on the fabrication of gas separation membranes by float-casting, even including the double layer membrane technique.10 11... 

R-134a is a non-flammable gas at room temperature and pressure with a normal boiling point of around 26°C. It is normally handled as a compressed gas under pressure in liquid form and has a liquid density of about 1300 kg/m With an extraction equipment design pressure requirement of only 20 bar or so, standard stainless steel fabrication techniques can be used with a significant cost saving, when implemented at industrial scale, over the more specialist techniques and materials required for operation at pressures greater than the 100 bar or so required for scC02. 

Scaffolds can be fabricated by using different types of methodologies such as fiber bonding, salt leaching, gas-induced foaming, phase separation, electrospinning, solid freeform fabrication, and molecular self assembly [15, 17]. Some of the fabrication techniques are discussed below. 

Significant improvements in MEA fabrication techniques have been made with the incorporation of Nafion -H into porous gas diffusion electrodes... 

Recommendation (Demo I) GA-2. Before construction of a full-scale supercritical water oxidation (SCWO) system, additional evaluations of constraction materials and fabrication techniques will be necessary because corrosion and plugging prevent continuous operation with the present design. If the new construction materials do not solve these problems, then alternative SCWO reactor designs should be investigated. 

The Tohoky University, Japan (Min et al.) reported a p-PEFC using micro-fabrication techniques [3]. This FC is based on two different designs, the alternatively inverted structure and the coplanar structure . These structures use Si substrates with porous SiOj layers with Pt-based catalytic electrodes and gas feed holes, glass substrates with micro-gas channels and a polymer membrane (Flemion S). In spite of a reported enhancement [4], the FC reached poor results, the power density is only 0.8 mW cm . ... 

The operation of metal-oxide gas sensors on plastic foil was successfully demonstrated. However, to make them fully compatible with large-scale fabrication techniques, additional work is required. So far, inkjet and gravure printing have been applied for the deposition of the gas sensing layer. However, the full printing of the transducers including the sensing layer still needs to be demonstrated. 

Target gas Detection range Operating temperature Sensing material Fabrication technique Ref. 

Sputtering has been used to incorporate a number of catal3 tic metals into microreactor devices. Examples include Pt, Zr, Mo, Pd, Ru, Rh, or alloys such as Pt-Ru. It is a convenient fabrication technique, although some researchers argue that the active surface area of the deposited catalyst is unsatisfactory. For many metals this problem can be overcome by sputtering using an oxygen-rich sputter gas rather than Ar alone. 

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