A Typical Experiment

A typical electrofocusing experiment with the apparatus just described is as follows  

The valve (26) is opened, and the cooling water is turned on. A pump or a funnel is used to add the electrode solution for the central electrode via the nipple (1). The electrode solution consists of the most concentrated sucrose solution to be used in the experiment. (A solution of the same sucrose concentration is added to the bottom of the separation compartments.) The electrode solution also contains a strong acid or a strong base, depending on whether the central electrode is to operate as 

The sample, the Ampholine carrier ampholytes and the sucrose solution are mixed by means of a gradient mixer or manually (see Section VI,5,6). The compartment (7) is filled so as to achieve a density gradient. Filling is done via nipple (2), using a funnel or pump. The second electrode solution is added on top of the solution to be electrofocused. This electrode solution consists of distilled water and acid or base, depending on whether the upper electrode is to be the anode or the cathode. 

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The accurate and absolute measurement of the distance, D, between the surfaces is central to the SFA teclmique. In a typical experiment, the SFA controls the base position, z, of the spring and simultaneously measures D, while the spring constant, k, is a known quantity. Ideally, the simple relationship A F(D) = IcA (D-z ) applies. Since surface forces are of limited range, one can set F(D = go) = 0 to obtain an absolute scale for the force. Furthennore, SF(D = cc)/8D 0 so that one can readily obtain a calibration of the distance control at large distances relying on an accurate measurement of D. Therefore, D and F are obtained at high accuracy to yield F(D), the so-called force versus distance cur >e. 

As a first step in imderstanding the analysis of energy transfer experiments, it is wortliwhile to summarize tire steps in a typical experiment where CgFg is tire hot donor and carbon dioxide is tire bath receptor molecule. First, excited... 

In a typical experiment 105 mg (0.50 mmol) of 3.8c, dissolved in a minimal amount of ethanol, and 100 mg (1.50 mmol) of 3.9 were added to a solution of 1.21g (5 mmol) of Cu(N03)2 BH20 and 5 mmol of ligand in 500 ml of water in a 500 ml flask. -Amino-acid containing solutions required addition of one equivalent of sodium hydroxide. When necessary, the pH was adjusted to a value of 5 ( -amino acids) and 7.5 (amines). The flask was sealed carefully and the solution was stirred for 2A hours, followed by extraction with ether. After drying over sodium sulfate the ether was evaporated. Tire endo-exo ratios were determined from the H-NMR spectra of the product mixtures as described in Chapter 2. 

Alkvl Azides from Alkyl Bromides and Sodium Azide General procedure for the synthesis of alkyl azides. In a typical experiment, benzyl bromide (360 mg, 2.1 mmol) in petroleum ether (3 mL) and sodium azide (180 mg, 2.76 mmol) in water (3 mL) are admixed in a round-bottomed flask. To this stirred solution, pillared clay (100 mg) is added and the reaction mixture is refluxed with constant stirring at 90-100 C until all the starting material is consumed, as obsen/ed by thin layer chromatographv using pure hexane as solvent. The reaction is quenched with water and the product extracted into ether. The ether extracts are washed with water and the organic layer dried over sodium sulfate. The removal of solvent under reduced pressure affords the pure alkyl azides as confirmed by the spectral analysis. ... 

In a typical experiment, Israelachvili deposited monolayers of surfactants onto cleaved mica sheets, and evaluated the surface energies using the JKR equation. Fig. 11 contrasts results for mica coated with monolayers of (a) L-a-dipalmitoyl-phosphatidylethanolamine (DMPE) where j/a = = 27 mJ/m and (b) hexa-decyltrimethylammonium bromide (CTAB) where = 20 mJ/m and = 50 mJ/m. ... 

In a typical experiment, triethylene glycol was treated with two equivalents of sodium toluenesulfonamide in dry DMF solution. After 6 h at reflux, the solution was distilled and product obtained by a standard work-up procedure. By this procedure, 9 was obtained in about 10% yield. The transformation is illustrated below as Eq. (4.10). Note also that Vogtle and his coworkers have also utilized phthalimide as a source of nitrogen in the preparation of such azacrown precursors as H2N(CH2CH2 0)2CH2CH2NH2 In such reactions, a standard hydrazine cleavage was used to remove the phthaloyl residue. 

Selective reduction of 11 to 12 is achieved in high yield by the use of 5% Rh-on-C in DMF containing NH OH. Reduction essentially stops after absorption of 3 mol of hydrogen. Yields were lower in ethanol. Platinum oxide in ammonical DMF showed fair selectivity, but Pd-on-C none. In a typical experiment, 0.1 mol of 11 in 250 ml DMF containing 3 ml 28% NH4OH solution and 0.7 g 5% Rh-on-Al O was reduced at 40 psig until 0.3 mol of hydrogen were absorbed (2). 

The following results were obtained in a typical experiment ... 

Inversion of the regioselectivity in the addition of 2-butenylmagnesium chloride to aldehydes in favor of the a-adducts is caused by aluminum trichloride. A typical experiment is shown24 ... 

Time Reduction and Increased Efficiencies. Time reduction and the corollary of increased efficiencies appear to be the main factors driving the short-term benefits deriving from implementation of an electronic notebook system. The argument is fairly simple, and there are good data [1] to show that the benefits are real and realistic. Most studies and projects associated with implementation of ELN within a research discipline focus on the reduction in time taken to set up a typical experiment and to document the experiment once completed. Further time savings are evident when examining workflows such as report or patent preparation, or when thinking about time taken to needlessly repeat previously executed experiments. 

The expression in Eq. (29) can be evaluated numerically for all values of t, and the results for three different waiting times are shown in Fig. 11 for c = 0.1. The value of Tmin = 2.0 ps at E/To = 5.7 x lO", derived from the present theory (also consistent with Goubau and Tait [101]) was used. The results for t = 10 ps demonstrate that, due to a lack of fast relaxing systems at low energies, short-time specific heat measurements can exhibit an apparent gap in the TLS spectrum. Otherwise, it is evident that the power-law asymptotics from Eq. (30) describes well Eq. (29) at the temperatures of a typical experiment. 

Figure 34. Plots of x as a function of time for a typical experiment in heat-transfer salts at 168°C. (Reprinted from 0. Odawara, 1. Okada, and K. Kawamura, "Measurement of Thermal Diffusivity of HTS by Optical Interferometry," J. Chem. Eng. Data 22 222-225, Copyright 1977 American Chemical Society.)...

In a typical experiment in a micro reactor, 67 wt.-% technical cumene hydroperoxide was reduced to 1.0 wt.-% [64]. A recycle ratio of 2 was applied. 

OS 85] ]R 33] ]P 65] By means of HPLC analysis, it could be shown that all three types of products were formed during reaction in the micro reactor [69]. For a typical experiment, the main fraction was composed of 4-mefhoxybenzaldehyde dimethylacetal, the second largest fraction consisted of the aldehyde and 4-methoxy-benzyl methyl ether was generated in a smaller amoimt. 

GL 1] [R 4] [P 2] A temperature rise of 0.4 K was estimated for a typical experiment in a dual-channel micro reactor based on assuming reaction rates and heat conductivity of the medium [13]. However, there are experimental indications that the real value is higher. 

In a typical experiment, linearly polarized pulsed laser fight of frequency co strikes the electrode snrface at an angle 9 from the snrface normal. The harmonic light of frequency 2co generated at or near the angle of specnlar reflection is analyzed... 

Reactions were carried out in liquid phase in a well-stirred (1000 rpm) high-pressure reactor (Parr Instruments, 300 mL) at 30 bar and 150°C with 370 mg catalyst for two hours, unless otherwise specified. The feed consisted of the amine with slight excess of ketone at ketone/amine-group molar ratio of 1.6 while maintaining a reaction volume of about 150 mL. In a typical experiment, 576 mmol of aniline is mixed with 920 mmol of cyclohexanone and 370 mg of BS2 catalyst in the 300 mL reactor. The reactor is closed and then pressure-tested to 50 psi above operating pressure to ensure that the system is leak proof Once pressure-tested, the headspace is replaced... 

A mechanistic model for the kinetics of gas hydrate formation was proposed by Englezos et al. (1987). The model contains one adjustable parameter for each gas hydrate forming substance. The parameters for methane and ethane were determined from experimental data in a semi-batch agitated gas-liquid vessel. During a typical experiment in such a vessel one monitors the rate of methane or ethane gas consumption, the temperature and the pressure. Gas hydrate formation is a crystallization process but the fact that it occurs from a gas-liquid system under pressure makes it difficult to measure and monitor in situ the particle size and particle size distribution as well as the concentration of the methane or ethane in the water phase. 

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