Edwards evaporator

An Edwards evaporator with freeze fracture accessory was used in this experiment, although any commercial freeze etch device can be used. The system must have provision for pumping liquid nitrogen into the specimen holder and temperature sensing and controlling devices. 

Special designs of direct rotaiy dryers, such as the Renneburg DehydrO-Mat (Edward Renneburg Sons Co.), are constructed especially to provide lower retention during the falling-rate diy-ing period for the escape of internal moisture from the solids. The DehydrO-Mat is a cocurrent diyer employing a smaU-diameter shell at the feed end, where rapid evaporation of surface moisture in the stream of initially hot gas is accomplished with low holdup. At the solids- and gas-exit end, the shell diameter is increased to reduce gas velocities and provide increased holdup for the solids while they are exposed to the partially cooled gas stream. 

Fig. 2 (a) Edwards E308 evaporator. One quartz-crystal thickness monitor is pointed towards the Au source to monitor Au vapor deposition on chamber walls the other monitors Au deposited through the shadow mask atop the organic layer. In the cold Au deposition, a small amount of Ar gas is added to the chamber to cool the Au atoms to room temperature before they physisorb atop the cryocooled organic monolayer, (b) Geometry of an Au I monolayer I Au pad sandwich, with electrical connections made using a Ga/In eutectic... 

Deposition of gold films (thermal evaporation technique). Evaporator with deposition chamber (e.g., Edwards Auto306B from Bewhay), chromium-plated tung-... 

From the above data Nicholson has calculated the latent heat of evaporation 10.3 kcal/mole. Edwards has given the following figures for temperatures ranging... 

Mn11 porphyrins are obtained in solution by reduction of Mnm complexes with sodium dithionite in the presence of pyridine [Calvin (23), Loach (124)], or in the solid state as a thin layer by evaporation of Mn111 porphyrins in high vacuum [Calvin (22), Edwards (52)]. No preparation of crystalline materials has been reported so far. 

A mathematical model of solvent blend evaporation was developed by Walsham and Edwards (61). The model accounts for the nonideal behavior of solvent blends in terms of component activity coefficients. The model allows accurate prediction of blend evaporation time by computer calculations. The technique provides a means to follow residual solvent composition (solvent balance) as evaporation proceeds. 

Edwards For the time of 100 ms. hexane will saturate independent of the evaporation rate dependence. 

V. N. Schultz, D. K. Edwards, and I. Catton, Experimental Determination of Evaporative Heat Transfer Coefficients on Horizontal, Threaded Tubes, AlChE Symp. Ser. (73/164) 223-227,1977. 

The heat of vaporisation at 25°C (AHvap.25) of a solvent is used to calculate the Hildebrand Solubility Parameter (HSP) assuming that the evaporating solvent behaves like an ideal gas. The HSP, subsequently, is one of the three parameters used in the Nelson, Hernwall and Edwards system to describe and predict the solvent power [17]. 

Edwards (62) had reported that one Kg (dry weight) of organic matter (cellulose) idien consumed by microorganism produced 0.597 Kg of water, 1.465 Kg of CO and 14,960 BTU. Some of the heat (about 59%) Is used to evaporate water produced dtnrlng the metabolic activity while the remaining (41%) Is left In the substrate to be dissipated. This amount of energy. If not dissipated Immediately, as It Is released, will reduce the productivity or may kill the organism. 

S-2500 Hitachi Thermo NORAN equipped with an energy-dispersive X-ray spectrometer and prior to the SEM studies the surface was gold or carbon-coated using a vacuum evaporator Edwards Auto 306. A Perkin Elmer System One spectrometer was used to obtain the FTIR spectrums while a Goniometre C diffractometer, incorporating a cobalt radiation (k = 1.78892 A) was used to obtain the X-ray diffraction patterns. 

Gibson, J. J., T. W. D. Edwards, G. G. Bursey T. D. Browse, 1993. Estimating evaporation using stable isotopes Quantitative results and sensitivity analysis for two catchments in northern Canada. Nord. Hydrol. 24 79-94. 

Polymer substrates were also metallized by evaporation. Prior to metal deposition, the specimens were cleaned in a 2 % aqueous detergent, rinsed and dried. A resistively-heated conical tungsten basket containing 99.99+ % purity copper foil served as the metal source. Typically 100-200 nm of metal was deposited in an Edwards E306A coating system. The chamber was evacuated to 2 x 10 4 Pa and held for at least 1 h prior to metal deposition in order to properly degas the substrates. Complete details of the evaporation procedure have been given previously... 

Walsham and Edwards [20] have developed a model which satisfactorily describes the evaporation behaviour of solvent blends. They based their work on that of Sletmoe [21], who found that the solvent evaporation rate was limited by boundary layer diffusion into the vapour phase. On this basis the rate of evaporation should be proportional to the vapour pressure of the solvent. Deviations in evaporation behaviour from ideality were directly analogous to deviations from Raoult s law of vapour pressures and could be corrected using activity coefficients. Since for most solvent molecules activity coefficients are largely deter-... 

For the calculation of evaporation rates the model of Walsham and Edwards [12] who use activity coefficients to calculate corrected relative evaporation rates is a good starting point. Nowadays these activity coefficients are, however, calculated with the UNIFAC group contribution method [6,7] and the evaporation rates take into account evaporative cooling of the blend [13]. 

The Hon. Edward Charles Howard (Darnell, Sheffield, 28 May 1774-London, 28 September 1816), third brother of the twelfth Duke of Norfolk, is best known for his invention of the vacuum pan for evaporating sugar syrup, which he patented in 1812. He found nickel in meteoric iron. ... 

Figure 3 (a) Edwards E308 evaporator, with Au source, two quartz crystal thickness monitors (one, QCMl, pointed to Au source, to... 

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