Automatic recorders

The vacustat f (Fig. 11,23,2) is another useful gauge it covers the range 10 to 0 01 mm. of mercury and is usually employed in conjunction with an oil pump. It is direct reading, compact, and is charged with only about 8 ml. of mercury. The gauge must be swivelled to the vertical position when a reading of the pressure is required it does not automatically record a variable pressure. 

Press the button on the electronic bubble meter. Visually capture a single bubble and electronically time the bubble. The accompanying printer will automatically record the calibration reading in liters per minute. 

Discussion. Potassium nitrate is an example of an inorganic compound which absorbs mainly in the ultraviolet, and can be employed to obtain experience in the use of a manually operated ultraviolet/visible spectrophotometer. Some of the exercise can also be carried out employing an automatic recording spectrophotometer (see Section 17.16). 

The absorbance and the percentage transmission of an approximately 0.1M potassium nitrate solution is measured over the wavelength range 240-360 nm at 5 nm intervals and at smaller intervals in the vicinity of the maxima or minima. Manual spectrophotometers are calibrated to read both absorbance and percentage transmission on the dial settings, whilst the automatic recording double beam spectrophotometers usually use chart paper printed with both scales. The linear conversion chart, Fig. 17.18, is useful for visualising the relationship between these two quantities. 

Procedure. The study can be carried out using either a manually operated single-beam spectrophotometer, or an automatic recording double-beam spectrophotometer. In both cases the wavelengths at which HMR and MR-exhibit absorption maxima are readily obtained from the spectra. 

Nearly all methemoglobln variants exhibit absorption spectra that are different from that of normal ferrlhemoglobln The absorption spectra are determined after the hemolysate Is dialyzed overnight at 4 0 against an 0 1 M phosphate buffer, pH 6 4 or 7 1, using an automatic recording spectrophotometer ... 

The spinning drop technique measures the shape of the oil drop in the flooding solution in a capillary tube. An automatic measuring system has been developed by combining a video-image analysis, an automatic recording system, and a computer for calculation of the interfacial tension [1865]. 

The method can successfully be used in analyses of impurities in metals and alloys, for estimation of minor elements in monomolecular films of oxide layers of Fe-Cr-Ni alloys, for detection of metal impurities in environmental pollution, for studying the depression of high-grade semiconducting materials and for analysis of the corrosion products of contact junction diodes used in microelectronic circuits. Much sophistication is desirable on the instrumental side so as to incorporate an automatic recording device to make an FR polarograph suitable for wider applications and common use. 

There are several electrical measurements that may be used for analysis of solutions under in situ conditions. Among the properties that may be measured are dielectric constants, electrical conductivity or resistivity, and the redox potential of solutions. These properties are easily measured with instrumentation that is readily adapted to automatic recording operation. However, most of these techniques should be used only after careful calibration and do not give better than 1% accuracy without unusual care in the experimental work. 

Advanced users bring their own remote-controlled equipment, install it in the beamline and couple it to the data acquisition system of the beamline for automatic recording of environmental parameters. 

Automatic Monitoring. The success of the experiment is strongly related to the ability of the data acquisition system to automatically record the relevant parameters during the experiment. Monitoring basic parameters by paper and pencil is only the last resort. 

Zimmerman, E. (1967). Automatic recording of viscosity changes with the Ostwald capillary viscometer. Anal. Biochem. 21, 81—85. 

The automatic recording of retention times, peak heights and areas, the identification of unknowns and... 

The technique and apparatus used in this work have been described in detail [81]. The reaction vessel was made hydrophobic by exposure to the vapour of trimethylchlorosilane and evacuated for several hours. Then isobutene, dried by sodium, and methylene dichloride, stored over calcium hydride, were distilled into it, the temperature adjusted, and the reaction started by the breaking of a phial containing a solution of titanium tetrachloride in methylene dichloride and one containing water. These could be broken in this, or the reverse, order, or simultaneously. The ensuing reaction was registered as a time-temperature curve by an automatic recorder. The range of conditions studied was [C4H8] = 0.05 -0.6 mole/1, [TiClJ = (0.1-5) x 10 3 mole/1, [H20] = (0.05-5) x 10 4 mole/1, T= 18°- -95°. 

The outlet from the column is connected to a detector usually fitted with an automatic recorder that permits exclusively the monitoring of the relative concentrations of the various constituents present in the sample. However, one may also make use of an automatic fraction collector duly attached to the outlet from the column, if required. The various experimental parameters stated below are normally given in the official monograph, namely ... 

As shown in Figure B2.1, double-beam spectrophotometers automatically record the true absorbance by measuring log(IR/Is), thanks to a double compartment containing two cuvettes, one filled with the solution and one filled with the solvent. Because the two cuvettes are never perfectly identical, the baseline of the instrument is first recorded (with both cuvettes filled with the solvent) and stored. Then, the solvent of the sample cuvette is replaced by the solution, and the true absorption spectrum is recorded. 

It may happen that experimental data are recorded with an insufficient number of observations or at inappropriate time points. In such cases, it is not possible to obtain insight into the curve profile and to compute metrics such as semi-invariants or even a Rescigno index. Amazingly, this situation is discussed mainly with respect to in vitro-release data, although modern equipment easily permits automatic recording of complete time profiles obviously, the problem does not exist for in vivo data despite the more pretentious experimentation. 

Monitor An apparatus which automatically records such physiological signs as respiration, pulse, and blood pressure in an anesthetized patient or one undergoing surgical or other procedures. [NIH]... 

Standard method of test for continuous analysis and automatic recording of the oxidant content of the atmosphere. Designation D 2011-65 (Reapproved 1972), pp. 924-928. In 1973 Annual Book of ASTM Standards. Part 23. Water Atmospheric Analysis. Philadelphia American Society for Testing and Materials, 1973. 

Morris RG (1996) Further studies of the role of hippocampal synaptic plasticity in spatial learning is hippocampal LTP a mechanism for automatically recording attended experience J Physiol Paris 90 333-334... 

Oxidations were carried out using about 2 ml. of chloroprene in an apparatus similar to that described by Bolland (5), modified for automatic recording. In some instances a gas-circulating system was used, in which oxygen from the reaction vessel passed through water in a conductivity cell, which was used to record the formation of hydrogen chloride (2). 

Induction Periods. Induction periods for squalane oxidation were measured using an automatic recording oxygen absorption apparatus (23). 

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