Hall-products

Figure 4.16 Single-screw compressor (Courtesy of APV Hall Products Ltd)...

L. A. R. Hall. Production of p-xylene polymers. US Patent 2719131, assigned to Du Pont, September 27, 1955. 

Evaluation and calibration. A piece of tube was rotated around its own axis during four channel wall thickness mea.surements (Figure 7). The four traces are not identical A rotation apart as should be expected. The calibrations of the four equipment s from the manufacture was not the same. Especially one of the traces has less dynamic than the other three. Based on these observations a dynamic calibration system was suggested using a tube, which could be rotated around its own axis in the measuring system. The values should be verified using traditional mechanical measurement around the tube circumference. The prototype system was permanently installed in the workshop at the production hall. Experimental work was more difficult under such circumstances so our participation in the development work stopped. 

The method of obtaining aluminum metal by the electrolysis of alumina dissolved in cryolite was discovered in 1886 by Hall in the U.S. and at about the same time by Heroult in France. Cryolite, a natural ore found in Greenland, is no longer widely used in commercial production, but has been replaced by an artificial mixture of sodium, aluminum, and calcium fluorides. 

There are currently two medicinally valuable alkaloids of commercial import obtained from ergot. Commercial production involves generation parasiticaHy on rye in the field or production in culture because a commercially useful synthesis is unavailable. The common technique today (65) is to grow the fungus in submerged culture. Clavicepspaspali (Stevens and Hall) is said to be more productive than C. purpurea (Fries). In this way, ergotamine (100,... 

Production of hydrogen fluoride from reaction of Cap2 with sulfuric acid is the largest user of fluorspar and accounts for approximately 60—65% of total U.S. consumption. The principal uses of hydrogen fluoride are ia the manufacture of aluminum fluoride and synthetic cryoHte for the Hall aluminum process and fluoropolymers and chlorofluorocarbons that are used as refrigerants, solvents, aerosols (qv), and ia plastics. Because of the concern that chlorofluorocarbons cause upper atmosphere ozone depletion, these compounds are being replaced by hydrochlorofluorocarbons and hydrofluorocarbons. 

A. K. Bhowmick, M. M. Hall, and H. A. Benarey, Rubber Products Manufacturing Technology, Marcel Dekker, Inc., New York, 1994. 

Decompositions may be exothermic or endothermic. Solids that decompose without melting upon heating are mostly such that can give rise to gaseous products. When a gas is made, the rate can be affected by the diffusional resistance of the product zone. Particle size is a factor. Aging of a solid can result in crystallization of the surface that has been found to affect the rate of reaction. Annealing reduces strains and slows any decomposition rates. The decompositions of some fine powders follow a first-order law. In other cases, the decomposed fraction x is in accordance with the Avrami-Erofeyev equation (cited by Galwey, Chemistry of Solids, Chapman Hall, 1967)... 

Hammer, W. 1980 Product Safety Management. Englewood Cliffs, NJ Prentice-Hall. 

Russell, R. S. and Taylor, B. W. 1995 Production and Operations Management Focusing on Quality and Competitiveness. Englewood Cliffs, NJ Prentice-Hall. 

MORTON-JONES, D. H. and ELLIS, J. w.. Polymer Products—Design, Materials and Processing, Chapman and Hall, London (1986)... 

Skeist, I. (Ed.), Handbook of Adhesives, 2nd ed. Chapman and Hall, New York, 1977. Zinkel, D.E. and Russell, J. (Eds.), Naval Stores. Production, Chemistry, Utilization. Pulp Chemical Association, New York, 1989. 

Bell and Hall have incorporated an organometallic unit into a crown by using the ferrocenyl unit as part of the ring or as a third strand. The unit is incorporated either as the 1,1 -diformylferrocene or the corresponding acid. In the former case, the bis-imine is prepared and reduced to give the saturated crown (see structure 24). In the latter case, the acid is converted into its corresponding chloride and thence into the diamide by reaction with a diamine. Diborane reduction affords the saturated amino-crown. Structure 24 could be prepared by either of these methods but the dialdehyde approach was reported to be poor compared to the amide approach which afforded the product in ca. 60% yield . 

An alternative route was later reported by Hall and Plant, who obtained 2 as well as the methyl derivative 110 in low yields, via the reaction of 5-aminotetrahydro-carbazoles with 2-chlorocyclohexanone, followed by dehydrogenation with palladium on charcoal of the intermediate octahydro derivatives 109 or 111 (53JCS116). The octahydro compounds 109 and 111 have also been reported as products from the reactions of suitable 1,3-phenylenediamines and 2-hydroxycyclohexanone in the presence of a catalytic amount of hydrochloric acid (53JCS4114). 

Craft, B. C., W. R. Holden, and E. D. Graves, Jr., Well Design-Drilling and Production, Prentice-Hall, Englewood Cliffs, New Jersey, 1962. 

Hill, T. J., Production/Operations Management, Prentice-Hall, Hemel Hempstead. 

Here, perhaps, is an opportunity for another young chemist like Hall to transform the production of boron as Hall did for aluminum (described later in this section). 

The annual production of aluminum in the United States in 2000 was 3.6 Mt (1 Mt = 1.0 X 109 kg). What mass of carbon, lost from the anode of the electrolysis cell, was required to produce this amount of aluminum by the Hall process ... 

Hall process (Hall-Herault process) The production of aluminum by the electrolysis of aluminum oxide dissolved in molten cryolite, haloalkane An alkane with a halogen substituent. 

TiB2 coatings for electrodes for aluminum production (Hall-cell cathodes). TiB2 has high resistance to molten aluminum yet it is readily wetted by the molten metal and good electrical contact is assured. 

---