Trough apparatus

Trog, m. trough vat tank pan hod. -apparat, m. trough apparatus, specif. (Elec.) trough battery, -batterle,/. trough battery. 

The isolation of the microbubble surfactant mixture from forest soil has been described in detail in preceding chapters. Quantitative examination of the surface properties of mono-molecular films of the isolated microbubble surfactant complex, at an air/water interface, were carried out using a modified Langmuir trough apparatus incorporating the surface tension method of Padday et al. (ref. 380). 

Figure 5. Electric charges induced on powders as a function of applied field in a vibrating-trough apparatus.

Pollock etal. [61] used a vibrating trough apparatus, fitted with an insulated electrode that permitted study of both contact and induction charging, to inves-... 

Fig. 3 Schematic depiction of the Langmuir trough apparatus and the positioning of the electrodes used in the lateral monolayer flow experiments. The inset shows the Au-coated glass slide working electrode modified with a self-assembled monolayer (SAM) of dodecanethiol. The working electrode is touching the air/water interface. A compound that forms a Langmuir monolayer is deposited on the water surface. It immediately spreads to cover the entire interface. Subsequently, the Langmuir film flows across the triple phase boundary into the SAM/water interface forming a bilayer. The lateral flow is completed when the entire electrode/solution interface is coated with a bilayer (from Ref 37).

Explore some commercial applications of surfactants as detergents and emulsifiers and familiarize yourself with the Langmuir trough apparatus. 

Because of the importance of surfactants in controlling and modifying the surface tension of fluids, it is appropriate here to describe methods for the measurement of surface tension and surfactant film characterization using the Langmuir trough apparatus. 

The Langmuir trough apparatus typically incorporates a mechanism for measuring the surface tension of the fluid interface (Figure 3.20). There are several methods used to achieve this measurement, and we review them briefly. Each involves exerting a force on the surface of the liquid in question and measuring the response. Surface tension of some common liquids at 25°C is shown in Table 3.2. 

A 5.2 X 10 -g sample of palmitic acid (C15H31COOH) is spread on a pure water surface as a solution in toluene and the solvent evaporated. Using a Langmuir trough apparatus, the monolayer is compressed to an area of 265 cm at which point it is known to form a close-packed monolayer. Calculate the area (in nm ) occupied by each molecule. 

Assemble the apparatus shown in Fig. 56. F is a 200 ml. flat-bottomed flask supported on a sand-bath and connected by a glass delivery-tube to the wash-bottle B, which is about two-thirds full of 10% aqueous sodium hydroxide solution. A second delivery-tube leads from B into a beehive stand (or between two earthenware tiles placed side by side) in a pneumatic trough T containing water. 

To prepare pure acetylene, assemble the apparatus shown in Fig. 57. F is a wide-necked 300 ml. bolt-head flask, to which is fitted a double-surface reflux water-condenser C and the dropping-funnel D. From the top of C, a delivery-tube leads down to the pneumatic trough T, where the gas can be collected in jars in the usual way. (Alternatively, use the apparatus shown in Fig. 23(A),... 

The apparatus consists of a tube T (Fig. 76) usually of total height about 75 cm. the upper portion of the tube has an internal diameter of about I cm., whilst the lower portion is blown out as shown into a bulb of about 100 ml. capacity. Near the top of T is the delivery-tube D of coarse-bored capillary, bent as shown. The tube T is suspended in an outer glass jacket J which contains the heating liquid this jacket is fitted around T by a split cork F which has a vertical groove cut or filed m the side to allow the subsequent expansion of the air in J. The open end of the side-arm D can be placed in a trough W containing water, end a tube C, calibrated in ml. from the top downwards, can be secured ts shown over the open end of D. 

An unusually extensive battery of experimental techniques was brought to bear on these comparisons of enantiomers with their racemic mixtures and of diastereomers with each other. A very sensitive Langmuir trough was constructed for the project, with temperature control from 15 to 40°C. In addition to the familiar force/area isotherms, which were used to compare all systems, measurements of surface potentials, surface shear viscosities, and dynamic suface tensions (for hysteresis only) were made on several systems with specially designed apparatus. Several microscopic techniques, epi-fluorescence optical microscopy, scanning tunneling microscopy, and electron microscopy, were applied to films of stearoylserine methyl ester, the most extensively investigated surfactant. 

The dynamic surface pressure was measured with a trough equipped with a couple of moving Teflon blades and an electronic balance, CHAN/Ventron, Cerritos, CA, U.S.A., similar to the apparatus describe by Mendenhall and Mendenhall [40], and by Bienkowski and Skolnick [41]. The trough coated... 

Figure 3.7 contains an illustration of the basic components of a typical electrophoresis apparatus. The troughs at either end contain an electrolyte buffer solution. The sample to be separated is placed in the approximate center of the electrophoresis strip. 

Apparatus used by Priestley for investigations on gases. The tub is Priestley s pneumatic trough. From Experiments on Different Kinds of Air. Image courtesy of School of Chemical Sciences, University of Illinois at Urbana-Champaign. 

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