Cases construction materials

Air Exchange. Mechanical control of display case conditions has been developed. Such systems condition the ambient museum air outside the case to a specific RH, and then introduce this conditioned air into the cases under low pressure. This system allows for several air changes per day within the case. A daily exchange of air within the case frequently removes pollutants that have been released from display case construction materials or from the artifact itself... 

Materials of Construction for Bulk Transport Because of the more severe service, construction materials for transportation usually are more restricted than for storage. Most large pipe lines are constructed of steel conforming to API Specification 5L or 5LX. Most tanks (cars, etc.) are built or pressure-vessel steels or AAR specification steels, with a few of aluminum or stainless steel. Carbon steel tanks may be hned with rubber, plastic, nickel, glass, or other materials. In many cases this is practic and cheaper than using a stainless-steel tank. Other materials for tank construction may be proposed and used if approved by the appropriate authorities (AAR and DOT). 

Selection of construction materials for rotors and casings is more limited than for centrifugal compressors. 

All aspects of the material s chemical, mechanical and physical properties which are included in the specification should be capable of measurement and certification. For critical duties all material supplied should be fully tested and certified by competent approved, independent test laboratories. All items of plant should be purchased with material certification. Additional certification is required in cases where the fabricator, in manufacturing an item of plant, used techniques such as welding or heat treatment which may affect the corrosion behavior of the construction materials. 

In selection of construction materials, the tendency is therefore to play safe stainless steel is on this account generally specified and is always used in cases of doubt. The suitability of other materials should not, however, be overlooked . Prior to the general advent of stainless steel in 1924, tinned copper was much in vogue. Today titanium, although expensive, represents a possible alternative". ... 

Catalysts and their carriers are provided in micro channels by various means and in various geometric forms. In a simple variant, the catalyst itself constitutes the micro-reactor construction material without need for any carrier [2-A], In this case, however, the catalyst surface area equals that of the reactor wall and hence is comparatively low. Accordingly, applications are typically restricted to either fast reactions or processing at low flow rates for slow reactions (to enhance the residence time). 

The metallic impurities present in an impure metal can be broadly divided into two groups those nobler (less electronegative) and those less noble or baser (more electronegative) as compared to the metal to be purified. Purification with respect to these two classes of impurities occurs due to the chemical and the electrochemical reactions that take place at the anode and at the cathode. At the anode, the impurities which are baser than the metal to be purified would go into solution by chemical displacement and by electrochemical reactions whereas the nobler impurities would remain behind as sludges. At the cathode, the baser impurities would not get electrolytically deposited because of the unfavorable electrode potential and the concentration of these impurities would build up in the electrolyte. If, however, the baser impurities enter the cell via the electrolyte or from the construction materials of the cell, there would be no accumulation or build up because these would readily co-deposit at the cathode and contaminate the metal. It is for this reason that it is extremely important to select the electrolyte and the construction materials of the cell carefully. In actual practice, some of the baser impurities do get transferred to the cathode due to chemical reactions. As an example, let the case of the electrorefining of vanadium in a molten electrolyte composed of sodium chloride-potassium chloride-vanadium dichloride be considered. Aluminum and iron are typically considered as baser and nobler impurities in the metal. When the impure metal is brought into contact with the molten electrolyte, the following reaction occurs... 

Experiments have shown the following results. The depth of penetration of the organic compound without catalysts is about 10-14 cm. However, the polymerization time is very long (about 2-3 days) and consumption of the compound is substantial (about 1-2 L/m2). The use of catalysts reduces the duration of the polymerization process to 1-3 hours. In this case the depth of penetration of chemicals into constructive materials is about 5-6 mm and consequently the consumption of organic compounds decreases. The treated materials have hydrophobic properties. The relation R does not depend on humidity of the surface of materials. 

High temperature processes produce a slag, a non-leachable, non-hazardous material suitable for use as construction materials. most cases. 

In the Inherent Safety Index corrosiveness is determined on the basis of the required construction material (Table 14). If carbon steel is enough, the index value is 0. For stainless steel the value is 1, but for all special materials the index is 2. The estimation is made for each process stream separately, and the worst case gives the final index value. 

Sauna Detoxification Therapy A Guide for the Chemically Sensitive. Marilyn G. McVicker. Jefferson, NC McFarland, 1997. Sauna detoxification therapy for MCS patients is covered, including case studies of MCS sufferers who have chosen sauna treatment.The unique requirements for a home sauna whose construction materials are suitable for MCS patients, and how to build one, are presented. Includes a directory of organizations and vendors. 

For pump casings constructed of materials other than steel or alloy steel or for pumps with nozzles larger than DN 400 (16 NPS), the vendor shall submit allowable nozzle loads corresponding to the format in Table 4. 

Number of stages Single/double suction Operating efficiency Vertical/horizontal mounting Rotational speed Impeller type Impeller diameter Construction materials Casing... 

In order to meet the above-mentioned conditions and also to minimize dust entry, modern cases are predominantly highly sealed, which implies that the air exchange rate would be lowered to a minimum. It is to be assumed that the high surface to volume ratio, which especially characterizes smaller enclosures, combined with unsuitable construction materials and almost static conditions, enhance the accumulation of chemical compounds. Hence, the comparison of the indoor environment as a reaction vessel , as stated by Weschler and Shields (1997), comes to a head in museum showcases. 

Schieweck, A., Markewitz, D. and Salthammer, T. (2007b) Screening emission analysis of construction materials and evaluation of airborne pollutants in newly constructed display cases, in Museum Microclimates, Contributions to the Conference in Copenhagen 19-23 November 2007 (eds T. Padfield and K. Borchersen), The National Museum of Denmark, Copenhagen, Denmark, pp. 67-72. 

Case S Sulzer Hydrogen Peroxide Distillation System (39). The safety in this new process is drastically improved because of low operating temperature, minimal product holdup in the system, reliable safety devices, and proper selection and treatment of the construction materials (39). 

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