Control of Experiments

Until the advent of modem physical methods for surface studies and computer control of experiments, our knowledge of electrode processes was derived mostly from electrochemical measurements (Chapter 12). By clever use of these measurements, together with electrocapillary studies, it was possible to derive considerable information on processes in the inner Helmholtz plane. Other important tools were the use of radioactive isotopes to study adsorption processes and the derivation of mechanisms for hydrogen evolution from isotope separation factors. Early on, extensive use was made of optical microscopy and X-ray diffraction (XRD) in the study of electrocrystallization of metals. In the past 30 years enormous progress has been made in the development and application of new physical methods for study of electrode processes at the molecular and atomic level. 

Hensch, T. K., Fagiolini, M., Mataga, N. et al. Local GABA circuit control of experience-dependent plasticity in developing visual cortex. Science 282 1504-1508,1998. 

Most of the techniques employed can be traced back to polarography, which was already in use in 1925, to determine the concentrations of organic molecules [3]. Technical developments in instrumentation (potentiostats) [4], the use of nonaque-ous electrolytes [5], and the digital control of experiments [6] led to the spread of electroanalytical techniques. For example, cyclic voltammograms are frequently and routinely used today to define the redox... 

At Dow we have standardized our workstations globally. I can go to any of the 50,000 workstations around the world and immediately get to my personalized desktop. The use of NetMeeting, remote network control of experiments, and the sharing of complex spectra and other data globally are standard at Dow, as they are across the chemical industry. All of this has had a large impact on the rate of collaboration. 

Most electrochemical studies carried out today make use of online computers for control of experiments and for data acquisition and analysis, including the techniques described earlier. Examples of the application of computer evaluation of experimental results include, for instance, pattern recognition [151] and the recording of current-time profiles of the form A(lni)/A(lnt) versus t for mechanistic classification [152] as well as nonlinear regression techniques [153-155]. Efforts have also been made to use knowledge-based systems for the elucidation of reaction mechanisms [156]. 

The rapid development of inexpensive microcomputers has increased their use in laboratory instrumentation. The function of laboratory instrumentation is usually simultaneous control of experiment and acquisition of measurement data. Processing of measurement data to values, graphs or tables can also be included. The personal computer is a powerful tool with capability for system control, data acquisition and data processing and combined with measuring equipment it can perform all the functions of larger and more expensive systems. 

Electrochemistry is a field, where control of experiments and data acquisition methods do not differ greatly, but proper interpretation of measured data gives information on several different phenomena. In electrochemical experiments one controls the system with electrical quantities and also measures electrical quantities, i.e. voltage and current. The electrochemical corrosion process, its probability and rate can be described as a function of three variables potential, current and time. Other electrical and electrochemical parameters can be derived from these variables. As an electrochemical process, corrosion can also be studied with electrical measurement methods. The measurements are suitable for automation which has the following advantages ... 

While automated data aquisition from laboratory instruments, control of experiments through robotics, automated data reduction and summary analysis have increased productivity in many laboratories, much work remains to be done. Automation from data acquisition through data presentation will be expanded. The manual keying of data will be minimised regardless of whether the source of the data is a laboratory instrument or an online database. Further, experimental design tools will be developed. 

With BFD, the computer becomes excellent not only for data logging, but also for strict timing control of experiments. BFD makes it easier for the GUI driven experiment control program to perform these tasks without the need for intimate knowledge of the hardware (i.e. the A/D converter chip used). The GUI experiment control program can operate without any changes despite possible hardware changes because BFD has provided a uniform interfiice to data control, acquisition and display. 

The operating organization shall submit to the regulatory body for review and assessment information on experiments and modifications that may affect reactor safety. The specific submission requirements will depend on the safety significance of the experiments and modifications. These requirements are described in Safety Series No. 35-S2. Specific guidance on the development of appropriate procedures for the control of experiments and modifications is provided in Safety Series No. 35-G2. 

The existence of the partitions is a well-known fact of all those who have had fun making soap bubbles but I had to submit to the control of experiment to establish the preceding results, and for the first time those which relate to the curvature of the partition and the angles under which this partition and the two films are cut. 

Let us add that our explanation could be subjected up to a certain point to the control of experiment in effect, if it is well founded, it is necessary obvionsly that, for the same opening, the phenomenon observed by Savart is much less marked as the load is stronger. 

---