Dadic and Pisk


Dutch State Mines (Stamicarbon). Vapor-phase, catalytic hydrogenation of phenol to cyclohexanone over palladium on alumina, Hcensed by Stamicarbon, the engineering subsidiary of DSM, gives a 95% yield at high conversion plus an additional 3% by dehydrogenation of coproduct cyclohexanol over a copper catalyst. Cyclohexane oxidation, an alternative route to cyclohexanone, is used in the United States and in Asia by DSM. A cyclohexane vapor-cloud explosion occurred in 1975 at a co-owned DSM plant in Flixborough, UK (12) the plant was rebuilt but later closed. In addition to the conventional Raschig process for hydroxylamine, DSM has developed a hydroxylamine phosphate—oxime (HPO) process for cyclohexanone oxime no by-product ammonium sulfate is produced. Catalytic ammonia oxidation is followed by absorption of NO in a buffered aqueous phosphoric acid  [c.430]

The coiled-tube heat exchanger offers unique advantages, especially when dealing with low-temperature design conditions where (1) simultaneous heat transfer between more than two streams is desired, (2) a large number of heat transfer units is required, and (3) high operating pressures are involved. Heat transfer for single-phase flow or either gas or hquid on the tubeside is generally well represented by either the Colburn correlation or modified forms oi the Dittus-Boelter relationship.  [c.1131]

SoUd Diffusion In the case of pore diffusion discussed above, transport occurs within the fluid phase contained inside the particle here the solute concentration is generally similar in magnitude to the external fluid concentration. A solute molecule transported by pore diffusion may attach to the sorbent and detach many times along its  [c.1511]

It took a long time for students of phase transformations to understand clearly that there exists an alternative way for a new phase to emerge by a diffusive process from a parent phase. This process is what the Nobel-prize-winning Dutch physicist Johannes van der Waals (1837-1923), in his doctoral thesis, first christened the spinodal . He recognised that a liquid beyond its liquid/gas critical point, having a negative compressibility, was unstable towards continuous changes. A negative Gibbs free energy has a similar effect, but this took a very long time to become clear. The matter was at last attacked head-on in a famous theoretical paper (based on a 1956 doctoral thesis) by the Swedish metallurgist Mats Hillert (1961) he studied theoretically both atomic segregation and atomic ordering, two alternative diffusional processes, in an unstable metallic solid solution. The issue was taken further by John Cahn and the late John Hilliard in a series of celebrated papers which has caused them to be regarded as the creators of the modern theory of spinodal decomposition first (Cahn and Hilliard 1958) they revived the concept of a diffu.se interface which gradually thickens as the unstable parent phase decomposes continuously into regions of diverging composition (but, typically, of similar crystal structure) later, John Cahn (1961) generalised the theory to three dimensions. It then emerged that a very clear example of spinodal decomposition in the solid state had been studied in detail as long ago as 1943, at the Cavendish by Daniel and  [c.104]

As mentioned earlier, if there is a large disparity in sttiicture at the film-substrate interface, such as a crystalline phase growing on an amorphous, glassy, substrate, the film may detach and grow a separate morphology.  [c.35]

Buchman, A. and Dodiuk-Kening, H., Laser surface treatment to improve adhesion. In Mittal, K.L. and Pizzi, A. (Eds.), Adhesion Promotion Techniques — Technological Applications. Dekker, New York, 1999, pp. 205-244.  [c.708]

When the preparation of the cuprous chloride is complete, place the diazonium solution in the dropping-funnel at the top of the reflux condenser, and then heat the flask containing the cuprous chloride on a boiling water-bath. When the cuprous chloride solution has been thoroughly heated, remove the water-bath, support the flask on a stand, and allow the diazonium solution to run slowly drop by drop down the condenser, meanwhile shaking the flask gently to ensure thorough mixing. As each drop of the diazo solution enters the liquid in the flask, a momentary separation of a yellow addition product, C H5N2Cl,Cu2Cl2, occurs this compound then breaks down, giving nitrogen and chlorobenzene, and the heat of the reaction maintains the temperature of the solution well above 60°. When all the diazonium solution has been added, allow the mixture to stand for 10 minutes, and then replace the flask on the boiling water-bath for a further 15 minutes in order to complete the reaction. Then detach the flask, equip it for steam-distillation (Fig. 15, p. 33) and steam-distil the contents until no more oily drops of chlorobenzene pass over. Place the distillate in a separating-funnel, and run off the lower layer of chlorobenzene into a small conical flask add a few pieces of granular calcium chloride, allow to stand for 15-20 minutes, and then filter the dry chlorobenzene directly into a 60 ml. distilling-flask. Fit the flask with an air-condenser, and distil the chlorobenzene, collecting the fraction which boils at 130-135°. Yield 18-19 g.  [c.190]

Remove the ether with the aid of the apparatus shown in Fig. II, 13, 4 the distilling flask should have a capacity of 50-75 ml. and the solution should flrst be Altered through a small fluted Alter paper. Remember to place 2-3 fragments of porous porcelain in the flask. Since ether is extremely volatile and also highly inflammable, the flask must be heated in a beaker or bath of warm water the water should be warmed in another part of the laboratory. Before commencing the distillation, read Section 11,13 (on the method of using the apparatus of Fig. II, 13, 4) and also Section 11,14 (fire hazards attending the distillation of inflammable solvents). When all the ethereal solution has been introduced into the flask and no more ether distils on a boiling water bath, detach the Buchner flask receiver and pour the ether into the ETHER RESIDUES bottle. Run out the water from the condenser, have two small conical flasks available as receivers, and distil the aniline either by direct heating over a wire gauze or, preferably, using an air bath (Fig. II, 5, 3). A small quantity of ether may pass over during the early part of the distillation it is therefore advisable to interpose an asbestos or uralite board between the receiver and the flame. Collect the fraction b.p, 180-184° in a weighed conical flask. The yield of aniline is 18 g.  [c.564]

When the preparation of the cuprous chloride is complete, place the diazonium solution in the dropping-funnel at the top of the reflux condenser, and then heat the flask containing the cuprous chloride on a boiling water-bath. When the cuprous chloride solution has been thoroughly heated, remove the water-bath, support the flask on a stand, and allow the diazonium solution to run slowly drop by drop down the condenser, meanwhile shaking the flask gently to ensure thorough mixing. As each drop of the diazo solution enters the liquid in the flask, a momentary separation of a yellow addition product, CgH6N2Cl,Cu2Cl2, occurs this compound then breaks down, giving nitrogen and chlorobenzene, and the heat of the reaction maintains the temperature of the solution well above 60°. When all the diazonium solution has been added, allow the mixture to stand for 10 minutes, and then replace the flask on the boiling water-bath for a further 15 minutes in order to complete the reaction. Then detach the flask, equip it for steam-distillation (Fig. 15, p. 33) and steam-distil the contents until no more oily drops of chlorobenzene pass over. Place the distillate in a separating-funnel, and run off the lower layer of chlorobenzene into a small conical flask add a few pieces of granular calcium chloride, allow to stand for 15-20 minutes, and then filter the dry chlorobenzene directly into a 60 ml. distilling-flask. Fit the flask with an air-condenser, and distil the chlorobenzene, collecting the fraction which boils at 130-135°. Yield 18-19 g.  [c.190]

T. L. Hill, P. H. Emmett and L. G. Joyner, J. Amer. Chem. Soc. 73, 5102 (1952) E. L. Pace and A. R. Siebert, J. Phys. Chem. 64, 961 (1960) J. R. Sams, G. Constabaris and G. D. Halsey, J. Phys. Chem. 66, 2154 (1962) J. de D. Lopez-Gonzalez, F. G. Carpenter and V. R. Deitz, J. Phys. Chem. 6S, 1112  [c.106]

Until the mid-1970s, acryhc fiber in 17—22 dtex (15 to 20 den) form was a primary competitor in the carpet market. Strict flammabihty regulations put in effect during this period provided the impetus for the development of flame-resistant acryhcs and modacryhcs. Fibers with high levels of vinyl chloride, vinyl bromide, or vinyhdene chloride were developed to pass government tests, such as the tunnel test and the methenamine pill test. These acryhc and modacryhc carpet fibers allow exceptional versatihty in styling and color patterns. Although acryhc carpets can also be superior to nylon aesthetically, dense and expensive constmctions are requited to match the pile height and durabihty of nylon carpets. In less dense constmctions acryhc carpets can develop wear patterns and lose resihence and pile height in the dye bath or in service under hot humid conditions. The carpet market is dominated by nylon staple fiber in the 1990s. A small market stiU exists in the United States and Europe in Japan acryhc carpets are stiU relatively popular. Numerous studies have been made to find ways of improving hot—wet and durabihty properties of acryhc carpet fibers. Fiber density and fibrillar stmcture can be improved by using modified compositions and spinning processes for high abrasion resistance. Producer dyed fibers and blends of acryhc and nylon have been developed to improve hot—wet performance.  [c.283]

Another approach to the production of high melting terephthalate-based copolyamides is first to make a low molecular weight prepolymer and then sohd-phase the material to higher molecular weight this process is similar in principle to that used in the manufacture of nylon-4,6. A variation of this process is used by Mitsui to produce its nylon-6,T/6,6 product, a copolymer of nylon-6,T and nylon-6,6 via a two-step process. First, an oligomer of the copolymer is made in an autoclave and spray-dried. The particles are then fed into an extmder, where the final copolymer is produced. A third approach, used by Du Pont, is to add a second diamine, 2-methylpentamethylenediamine (trade name Dytek A) rather than a second diacid to reduce the melting point (194,195). This nylon-6,T/D,T copolymer is produced via an all-melt phase process in an autoclave. Although the resulting polymer has a high melt point, the process avoids the added cost of special process equipment and handling. Table 11 presents information on most of the high temperature resins that have been introduced into the marketplace nylon-6,6 and nylon-4,6 are included for comparison.  [c.238]

Precipitated and pyrogenic siUcas are widely employed ia antifoams used ia iadustry. To be effective, the siUca surface must be rendered hydrophobic by reaction with an agent such as polydimethylsiloxane. The hydrophobic particles are dispersed ia a carrier fluid such as mineral or siUcone oil. The mechanism of bubble breaking is disputed (107,108). One theory is that the mechanism is dewettiag of the siUca particle by the foam lamella, which creates a defect ia the film that leads to its mpture. The criterion for dewettiag is a three-phase contact angle of 90° or more. The three phases are the aqueous foam lamella, the soHd siUca particle, and the carrier oil. The properties of precipitated siUca that optimize its performance ia the largest U.S. use, ie, pulp (qv) and paper (qv) defoaming, have been identified for the two common methods of hydrophobiag dry-roast (109) and in situ (110). Other defoaming appHcations iaclude paint and coatings, textile dye baths, and, particularly ia Europe, laundry detergents.  [c.481]

Sensitization. The skin irritation and sensitization potentials of 9.0% thioglycolic acid were evaluated usiag the open epicutaneous test. Reactions were not observed dutiag the challenge phase. ThioglycoHc acid was an irritant, but not a sensitizer (20).  [c.5]

Step 5 deals with the process flow diagram. The calculations procedure that the early simulators used, stiU the most common ia iadustriaHy used simulators, consists of making calculations around each unit operation of a process ia a sequence of unit operations through which the main material flows. These simulators are known as block sequential or sequential modular simulators. The topology of the process (including all recycles and purges) must be given to the simulator, each of which has an equivalent way of entering iaputs and outputs of each unit operation or source and destination of each stream. There is a trend toward enabling an engineer to draw the flow diagram on a computer screen and have the computet program pick up the needed information about the topology of the process directly from the dtawiag.  [c.73]

Prototyping. As Figure 3 shows, the prototypiag step is a parallel activity with kaowledge acquisitioa, coaducted ia an iterative fashion. Unlike traditional software appHcations, knowledge-based systems are difficult to specify exactly dutiag the problem analysis phase. Intermediate results from the prototypiag step may help with further kaowledge acquisitioa. The prototypes can help get feedback from the end users. Prototypiag also results ia a phased developmeat effort as modules of the system get developed, they can be tested and even used, while development on other modules progresses. This step requires a good understanding of representation techniques, rea soning methods, and the features of the development tool. Experts and knowledge engineers are the primary participants ia this phase however, ead users may also be iavolved to provide feedback oa system performance.  [c.538]

Chromatographic Analyzers Chromatographic analyzers are widely used for the separation and measurement of volatile compounds and of compounds that can be quantitatively converted into volatile derivatives. These materials are separated by placing a portion of the sample in a chromatographic column and carrying the compounds through the column with a gas stream. As a result of the different affinities of the sample components for the column packing, the compounds emerge successively as binary mixtures with the carrier gas. A detec tor at the column outlet measures some physical property which can be related to the concentrations of the compounds in the carrier gas. Both the concentration peak height and the peak height-time integral, (i.e., peak area) can be related to the concentration of the compound in the original sample. The two detectors most commonly used for process chromatographs are the thermal-conductivity detector and the hydrogen-flame ionization detector. Thermal-conductivity detec tors, discussed earlier, require calibration for the thermal response of each compound. Hydrogen-flame ionization detec tors are more complicated than thermal-conductivity detectors but are capable of 100 to 10,000 times greater sensitivity for hydrocarbons and organic compounds. For iiltrasensitive detection of trace impurities, carrier gases must be specially purified.  [c.765]

Probability Screening Principle Probability screening uses the fact that particles moving almost at right angles to a screening surface are not hkely to pass through when the particle size is greater than about half of the distance between the screen elements. Screens utilizing the probability principle are manufacturing by Dutch State Mines (DSM), Bartles (CTS), and Morgensen. The last-named incorporates multiple decks. Higher throughput, longer screen life, and lower capital costs are claimed for these screening systems. The performance of several types of probabihty screens was reviewed by Moir (op cit.).  [c.1774]

In 1951, this strain-ageing law was checked by Harper (1951) by a method which perfectly encapsulates the changes which were transforming physical metallurgy around the middle of the century. It was necessary to measure the change with time free carbon dissolved in the iron, and to do this in spite of the fact that the solubility of carbon in iron at ambient temperature is only a minute fraction of one per cent. Harper performed this apparently impossible task and obtained the plots shown in Figure 5.1, by using a torsional pendulum, invented just as the War began by a Dutch physicist, Snoek (1940, 1941), though his work did not become known outside the Netherlands until after the War. Harper s/Snoek s apparatus is shown in Figure 5.2(a). The specimen is in the form of a wire held under slight ten.sion in the elastic regime, and the inertia arm is sent into free torsional oscillation. The amplitude of oscillation gradually decays because of internal friction, or damping this damping had been shown to be caused by dissolved carbon (and nitrogen, when that was present also). Roughly speaking, the dissolved carbon atoms, being small, sit in interstitial lattice sites close to an edge of the cubic unit cell of iron, and when that edge is elastically compressed and one perpendicular to it is stretched by an applied stress, then the equilibrium concentrations of carbon in sites along the two cube edges become slightly different the carbon atoms prefer to sit in sites where the space available is slightly enhanced. After half a cycle of oscillation, the compressed edge becomes stretched and vice versa. When the frequency of oscillation matches the most probable jump frequency of carbon atoms between adjacent sites, then the damping is a maximum. By finding how the temperature of peak damping varies with the (adjustable) pendulum frequency (Figure 5.2(b)), the jump frequency and hence the diffusion coefficient can be determined, even below  [c.192]

The heat exchangers described are so powerful that heat extraction from the outside air is now an economic possibility, when no ground or surface water is available. A Coefficient Of Performance of 6 is attainable as a mean over the Dutch heating season (inside temperature 20 °C, outside 4.8 °C) according to Fiwihex, with the following configuration 2 X1000 W/°C propane-to water heat exchangers 2x500 W/°C fans and a standard shop display refrigeration compressor. The heat pump stops during electricity peak hours when the heat storage system has been installed. When (ground)water as a heat source is available, the COP rises to 8.  [c.24]

The High Flux Isotope Reactor (HFIR) is a high neutron flux density isotope production and research reactor in operation at ORNL since 1965 for transuranic and cobalt isotope production, materials irradiation and neutron scattering research. It is a 85-MWt flux trap reactor using water cooling (468 psig and 158° F, outlet) with a beryllium moderator. The peak thermal flux in the flux trap is 5E15 n/cm sec is the highest in the world. The reactor core is 17.5 in. dia and 24 in. high with a 5 in. dia. target hole in its center for the flux trap. The core has 9.6 kg of 93% enriched U-235 arranged in two concentric, cylindrical elements. The inner element contains 171 and the outer 369 involute aluminum-clad fuel plates. Both elements of the core are replaced every 24 days. The moderator is about 1 ft thick. Control is achieved by four safety plates arranged in a cylinder around a solid control cylinder. These control cylinders are located between the core and the Be reflector. Insertion of any one of the five control elements renders the core subcritical. The reactor core is contained in an 8-foot-diameter pressure vessel that is 19 ft high located near the bottom of pool of 85,000 gal. of water for shielding and to prevent core uncovery. A flow rate of 16,000 gpm is provided by 3/4 (three-out-of-four) main AC cooling pumps with DC motor backup. Pressure is provided by (Vi) pressurizer pumps whose speed is controlled by controlling the slip in a hystersis dutch.  [c.414]

T. L. Hill, P. H. Emmett and L. G. Joyner, J. Amer. Chem. Soc. 73, 5102 (1952) E. L. Pace and A. R. Siebert, J. Phys. Chem. 64, 961 (1960) J. R. Sams, G. Constabaris and G. D. Halsey, J. Phys. Chem. 66, 2154 (1962) J. de D. Lopez-Gonzalez, F. G. Carpenter and V. R. Deitz, J. Phys. Chem. 65, 1112  [c.106]


See pages that mention the term Dadic and Pisk : [c.692]    [c.692]    [c.134]    [c.2115]    [c.216]    [c.459]    [c.46]    [c.77]    [c.570]    [c.137]    [c.127]    [c.151]    [c.770]    [c.746]   
See chapters in:

Cellular automata  -> Dadic and Pisk