Clamp

Figure 3. Sheared speckle image of a square aluminium plate clamped along all four sides...

Figure 4. (a) Correlation image of centrally loaded square aluminium plate clamped along all four sides, (b) Raw phase map shearogram. (c) Image enhanced phase map. 

In this equation, m. is the effective mass of the reaction coordinate, q(t -1 q ) is the friction kernel calculated with the reaction coordinate clamped at the barrier top, and 5 F(t) is the fluctuating force from all other degrees of freedom with the reaction coordinate so configured. The friction kernel and force fluctuations are related by the fluctuation-dissipation relation... 

Here, t is the nuclear kinetic energy operator, and so all terms describing the electronic kinetic energy, electron-electron and electron-nuclear interactions, as well as the nuclear-nuclear interaction potential function, are collected together. This sum of terms is often called the clamped nuclei Hamiltonian as it describes the electrons moving around the nuclei at a particular configrrration R. 

Ah initio calculation s can be performetl at th e Ilartree-Fock level of approximation, equivalent to a self-con sisten t-field (SCK) calculation. or at a post llartree-Fock level which includes the effects of correlation —defined to be everything that the Hartree-Fock level of appi oxiniation leaves out of a n on-relativistic solution to the Schrddinger ec nation (within the clamped-nuclei Born-Oppenh e-imer approximation ). 

Ensure that all the individual components in the assembly are adequately supported when in position the friction between contiguous ground-glass surfaces does not provide adequate support. Therefore always use clamps, the claws of which are lined with rubber or other soft material. When assembling apparatus, allow some play in the clamps until the individual parts are in position, and then secure the position of the assembly by gently increasing the pressure of the clamps. 

Chromatographic Separation of a Mixture of o- and p-Nitroaniline. Prepare a glass tube A (Fig. 24) in which the wider portion has a diameter of 3 cm. and a length of ca. 30 cm. the narrow portion at the base has a diameter of 5-7 mm. Wash the tube thoroughly (if necessary, with chromic acid, followed by distilled water and ethanol) and then dry. Insert a small plug of cotton-wool P as shown just within the narrow neck of the tube it is essential that this plug does not project into the wider portion of the tube. Clamp the tube in a vertical position. 

Mix 100 g. of active alumina with dry benzene until a suspension or slurry of suitable consistency is obtained, and pour this carefully into the tube. Clamp a dropping-funnel just above the top of the tube and Fig 2 benzene to run slowly down as the alumina... 

The heating of the vessels is accomplished by means of a small bath or a micro-Bunsen burner. The vessel can be clamped at such a distance from the burner that the contained liquid boils gently under reflux. Smooth boiling is ensured by the addition of 1-2 minute pieces of unglazed porcelain, or of a short piece of melting-point tubing open at both ends. 

A very suitable apparatus for semi-micro steam-distillation, particularly for suspensions that are likely to bump badly, is showm in Fig. 44. This consists of a 50 ml. Kjeldahl flask, clamped at an angle of 45°, and fitted with a long glass tube for the inlet of steam. The Outlet-tube is bent twice, first at 135° and then at 45° as shown, and fitted into a small water-condenser. 

The complete filtration apparatus is shown in Fig. 5, p. 11. A simpler and cheaper apparatus is shown in Fig. 45. This consists of a boiling-tube A having a side-arm for connection to the pump the tube A is conveniently held in a wooden or cork block B or in a clamp. The funnel F may be fitted into A through a pliable rubber disc D the latter is more useful than a cork since it covers tubes of various diameters. The filtrate is collected in the centrifuge-tube T. 

Lead formate separates from aqueous solution without water of crystallisation. It can therefore be used for the preparation of anhydrous formic acid. For this purpose, the powdered lead formate is placed in the inner tube of an ordinary jacketed cond ser, and there held loosely in position by plugs of glass-wool. The condenser is then clamped in an oblique position and the lower end fitted into a receiver closed with a calcium chloride tube. A current of dry hydrogen sulphide is passed down the inner tube of the condenser, whilst steam is passed through the jacket. The formic acid which is liberated... 

Place 20 g. of dry powdered benzoic acid in C, add 15 ml. (25 g., i.e., a 30% excess) of thionyl chloride and some fragments of porcelain, and then clamp the apparatus on a boiling water-bath as shown so that no liquid can collect in the side-arm of C. Heat for one hour (with occasional gentle shaking), by which time the evolution of gas will be complete. Cool the flask C, detach the condenser and fit it to the side-arm for distillation, using a 360° thermometer for the neck of C. To the lower end of the condenser fit a small conical flask G (Fig. 67(B)) by a cork carrying also a calcium chloride tube. 

A powerful stirrer, driven by a flexible driving shaft between the motor (I h.p.) and the stirrer, is depicted in Fig. II, 7, 3. The motor may be placed at a distance from the stirrer head and reaction vessel, thus enabling the assembly to be used for inflammable, corrosive or fuming liquids without damage to the motor. Furthermore, any laboratory retort stand and clamp may be used since the stirrer head weighs only about 250 grams. A variable speed control (500-2000 r.p.m.) is provided. 

Two convenient forms of bath are shown ui Fig. 11,10, 2, a and 6. The former consists of a long-necked, round-bottomed flask (a longnecked Kjeldahl flask of 100 ml. capacity is quite satisfactory) supported by means of a clamp near the upper part of the neck. The thermometer is fltted through a cork, a section of the cork being cut away (see inset) so that the thermometer scale is visible and also to allow free expansion of the air in the apparatus. The bulb is about three-quarters filled with... 

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