Metal channel

In another appHcation expanded polystyrene foam panels, 1.2 x 2.4 m, are faced with a wire mesh and mounted ia a metal channel bolted to a coacrete slab. These panels are then sprayed on both sides with plaster, which is anchored to the wire mesh and forms the iaterior and exterior surfaces. Roof and iaterior partitioas provide low cost housiag for mild climates. 

The geometry for this system is shown in Figure 1. Polymer melt enters a rectangular metal channel with... 

Liquid-Metal Channel Voiding and Expulsion Models 297... 

For the fiber-metal insulator, the beta-Ti alloys, Ti-13V-llCr-3Al, Ti-2.5Al-16V, and Ti-7Al-4Mo are the current selections, based on existing commercial alloys. Improved Ti alloys or use of a Nb alloy layer next to the Cauldron wall may be necessary to avoid creep at the highest temperatures. A helium sweep gas would be used to remove tritium from the porous fiber-metal channel. 

Step 15. In the indirect contact furnace, natural gas containing 92.5 mole% methane, 4.8 mole % ethane, and the remainder propane is burned completely with excess air (combustion air). The dryer air feed stream (the combination of makeup dryer air and humid air recycled from the dryer outlet) passes through metal channels within the furnace combustion zone and then out of the furnace to the rotary dryer air inlet. The hot gases in... 

The incorporation of a particulate reinforcement into the ceramic matrix produces a refinement of the matrix, i.e., both the ceramic ligament and metal channel sizes are decreased [37]. Although the reinforcement particles effectively break up any macroscopically apparent columnar growth of the matrix, some preferred orientation of the A1203 is still observed by x-ray diffraction analysis. In the specific case examined, approximately one-half of the surface area of the reinforcement particles was found to be directly bonded to the interconnected A1203 of the matrix the balance was in contact with the metallic constituent. 

The microstructures of ceramic matrices grown from two different classes of alloys have been reported. The external growth surface of ceramic matrices grown from an Al-Si-Mg alloy in the absence of a reinforcement was covered by a thin ( 1- to 4-gm) layer of MgO that sometimes contained up to 5% MgAl204 [33]. The external MgO layer typically was separated from the interconnected A1203 matrix by a thin aluminum alloy (1- to 3-gm) layer. Only rarely was an A1203 grain found in direct contact with the external oxide layer. Within the bulk of the composite, the metallic channels typically were 3 to 8 /tm in width. 

As described, the addition of Mg to an aluminum alloy permits rapid oxidation of the alloy at elevated temperatures in an oxygen-containing atmosphere. The product is a composite composed of a matrix of interconnected A1203 with a small fraction of residual A1 alloy dispersed in the matrix as interconnected metal channels. From a thermodynamic or phase diagram viewpoint, three distinct oxides can form when an Al-Mg alloy is exposed to such an atmosphere A1203, MgAl204, or MgO. The specific... 

Fig. 6.2 PMT dynode geometries. Circular dynode arrangement, linear focused, fine mesh, Venetian blind, metal channel type. C Cathode, D dynodes, A anode, F focusing electrode,...

Of special interest for time-correlated single photon counting are the linear fo-cused dynodes, which give fast single electron response and low transit-time jitter, and the fine mesh and metal channel types, which offer position sensitivity when used with an array of anodes. Moreover, PMTs with fine-mesh and metal channel dynodes can be made extremely small, which results in low transit time, low transit-time jitter, and a fast single-electron response. 

Fig. 6.4 Multianode PMT with metal channel dynodes left) and multianode MCP-PMT right)...

The TTS of conventional PMTs and miniature PMTs with metal channel dyn-odes can be measured with satisfactory accuracy using picosecond diode lasers. These lasers deliver pulses as short as 30 to 50 ps FWHM. However, the pulses may have a tail or a shoulder, especially at higher power. The diode driving conditions for clean pulse shape with minimum tail are usually not the same as for shortest FWHM. The TTS of MCP PMTs ean be reasonably measured only by a Ti Sapphire laser or a similar femtoseeond or picosecond laser system. 

The metal-channel design of the R5600 and R7400 results in slight periodical variations of the efficiency and the IRF over the active area, see Fig. 6.41. Consequently, either the entire active area should be illuminated or the position of the illuminated spot should be kept stable. Variations in the position can be a pitfall in TCSPC scanning applications (see Fig. 5.93, page 158). 

Unfortunately, this was not the end of the story. Under very high temperature conditions of the fuel and of the metallic channel materials, water and steam may react, here too in an auto-enhancing way, with the metallic materials generating hydrogen and... 

In the channel black process, diffusion flames burning natural-gas impinge on reciprocating metal channels where carbon is deposited. Rotating drums may also be used. The carbon is scraped off, collected, micro-pulverised and then usually pelletised. These blacks have a much higher combined oxygen content than furnace blacks. This process is little nsed now largely dne to unfavourable economics and environmental problems. 

The second range of products contains the foaming and syntactic adhesives. These are the materials which can be used to sphce sheets of honeycomb together, to join honeycomb to metallic channelling. 

Extrusion dies are metal channels that impart a specific cross-sectional shape to a polymer stream. The design difficulty centers on achieving the desired shape within set limits of dimensional uniformity at the highest production rate possible. Because of the viscoelastic nature of polymers and the associated flow behavior, it is no simple matter to design a die that will produce a smooth extrudate with the desired dimensions. 

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