Barrie Blake-Coleman - Academia.edu (original) (raw)

Papers by Barrie Blake-Coleman

Trends in Biotechnology, 1986

... In discussing physical methods, it would be a mistake to consider only monitoring biomass con... more ... In discussing physical methods, it would be a mistake to consider only monitoring biomass concentration in fermentors ... However, recent development of magnetic field induced impedance monitoring tech niques have provided sensitive, non invasive methods of detecting ...

This work critically examines the principal events and circumstances which influenced the course ... more This work critically examines the principal events and circumstances which influenced the course and rise of a crucial component in modern electrical technology - copper wire. This material, through successive eras, has played a variety of roles and enjoyed a range of distinct applications. In charting the development, manufacture and use of copper wire, the thesis describes how in its earlier history a traditionally made product, applied to traditional purposes (in arts and trades themselves subject to change) evolved into something which, in property and quality, was entirely different - electrical conductors. By 1850, copper wire can be said to have long begun its exchange of a traditional role for a modern one, having by this time found application as a telegraph conductor, with varying degrees of success. In this respect, early trials in overland and submarine telegraphy, as well as experiments on metallic conductors, are shown to have been major influences in the development o...

The all too common outcome of a seemingly predictable chain of events is catastrophe. The more yo... more The all too common outcome of a seemingly predictable chain of events is catastrophe. The more you attempt to avoid it, the worse it appears to get; thus has Murphy's Law been recognized. We surmise that the Murphy Syndrome occurs too frequently to be pure chance, though reason counsels otherwise. Is Murphy's Law a satanic malevolence, an unseen and fiendish

IEE Proceedings A Physical Science, Measurement and Instrumentation, Management and Education, Reviews, 1981

Samples of copper wire from the coils and toroids made and used by Michael Faraday (1791-1867), d... more Samples of copper wire from the coils and toroids made and used by Michael Faraday (1791-1867), during the period of his greatest electrical discoveries, were inspected for quality of manufacture and tested chemically and electrically to determine metal purity and electrical conductivity. The outcome of the enquiry establishes that the copper wire of Faraday's time was not only indifferently made but retained a wide range of impurities. As a consequence, an extreme range of conductivities was found corresponding to the type, and concentration, of elemental impurities in any one sample. The paper concludes that there is some basis for believing that had other factors weighed slightly more against Faraday, then his failure to be selective in the conductivity of his wire may well have lost him the credit for the discovery of electromagnetic induction.

Measurement Science and Technology, 1994

A straightforward but unique current to voltage converter is described which, in conjunction with... more A straightforward but unique current to voltage converter is described which, in conjunction with a standard frequency response analyser (FRA), allows impedance measurements to be performed. The circuit topology minimizes the effects of parasitic impedance components enabling the quantitative measurements of high-impedance elements into the gigohm region-a feature not found on standard impedance bridges. This capability has application in areas such as measurements on ion selective electrodes. The combined facility provides a generally useful impedance analyser. However, its immediate utility was in the study of low-frequency electrode-electrolyte systems, to which the data presented relate. The circuit provides accuracy and stability, and is inexpensive to construct from readily available components.

Journal of Biotechnology, 1984

Biotechnology and Bioengineering, 1986

Acoustic resonance densitometry (ARD) is reported as a method suitable not only for precise inves... more Acoustic resonance densitometry (ARD) is reported as a method suitable not only for precise investigations into changes of specific gravity in bioreactor media but also as a technique able to provide an accurate wide range and direct determination of cellular mass in fermentation processes. It is further shown that this method can replace present optical procedures, minimizing dilution errors and operator involvement and is suitable for development as an on-line biomass monitoring system.

Biotechnology and Bioengineering, 1989

Acoustic resonance densitometry (ARD) provides a highly reproducible and stable method for on-lin... more Acoustic resonance densitometry (ARD) provides a highly reproducible and stable method for on-line measurement of culture biomass density. The technique provides a direct determination of changes in relative density of culture medium and cell mass. At cell concentrations higher than lo6 cells mL-' this method can replace cell counts and provide a continuous measure of total cell mass. In cultures of hybridomas or U937 human lymphoma cells, the ARD value correlates well with cell number except when the average cell size changes during culture. It is argued that cell mass determined by ARD rather than cell number should be used as the basis for measurements of specific biological activity.

Biosensors and Bioelectronics, 1994

The frequency/amplitude effect of various microorganisms exposed to periodic (time varying) elect... more The frequency/amplitude effect of various microorganisms exposed to periodic (time varying) electric fields, when proximate to immersed electrodes, has been studied using a novel analytical instrument. The harmonic distribution, in complex signals caused by cells exposed to harmonic free waveforms and occupying part of the electrode/suspension interface volume, was shown to be almost entirely due to the change in the standing interfacial transfer function by the (dielectrically nonlinear) presence of cells. Thus, the characteristic interfacial non-linearity is viewed as variable, being uniquely modulated by the presence of particular cells in the interfacial region. Little can be attributed to bulk (far field) effects. The tendency for subtle (characteristic) signal distortion to occur as a function of particulate (cell or molecular) occupancy of the near electrode interfacial region under controlled current conditions leads to the method of sample characterisation by harmonic (Fourier) analysis. We report here, as a sequel to our original studies (Hutchings et al., 1993; Hutchings and Blake-Coleman, 1993), preliminary results of the harmonic analysis of microbial suspensions under controlled signal conditions using a three-electrode configuration. These data provide three-dimensional graphical representations producing harmonic 'surfaces' for various microorganisms. Thus, cell type differences are characterised by their 'harmonic signature'. The visual distinction provided by these 'surface' forming three-dimensional plots is striking and gives a convincing impression of the ability to identify and enumerate specific microorganisms by acquisition of cell-modulated electrode interfacial Fourier spectra.

Trends in Analytical Chemistry, 1984

ling the fermentation temperature through adjustment of the supply of cooling water to the vats. ... more ling the fermentation temperature through adjustment of the supply of cooling water to the vats. More sophisticated adaptive control procedures will use computerized 'learning systems'-essentially a self-generating expert system-to control fermentation processes on the basis of a much more complex heuristic model. Such models can be constructed initially from expertise collected during process development, but can quickly evolve into expert systems capable of recognizing-and acting upon-all possible combinations of process parameters. A major part of the data base required for such control systems will be based on readings from yetto-be-developed real-time chemical sensors of the kind discussed above, as well as from conventionaltechnology sensors. The computer technology for such a development is here today. All we need are robust, reliable sensors! References 1 C. L. Cooney, in W. B. Armiger (Editor), Proc. lnd. Int.

Review of Scientific Instruments, 1991

ABSTRACT

Biosensors, Feb 1, 1989

Non-invasive and fully automated conductimetric measurements of electrolyte and bacterial samples... more Non-invasive and fully automated conductimetric measurements of electrolyte and bacterial samples were achieved in a closed volume test cell, comprising a magnetic field coil and detector. By monitoring field induced currents in sample electrolytes the magnitude of the sample current was shown to vary as the inverse of the sample impedance. The impedance characteristic was shown to be that of an LCR resonant circuit. This characteristic is primarily a function of the applied frequency and the solutionlcell properties being dependent on the solution conductivity and dielectric permittivity at any given concentration. Small changes in sample dielectric permittivity in the presence of a large background conductivity are shown to be significant. The apparatus described can provide fixed or swept frequency conductivity measurements in the range 1 kHz to 2.25 MHz with a lower conductivity sensitivity of 0.9 x 10-s Scm-t. Bulk impedimetric characteristics of cell suspensions are derived by a two stage measurement.

Biosensors & Bioelectronics, 1990

Instrument performance and application was evaluated with a variety of microbial suspensions. Dat... more Instrument performance and application was evaluated with a variety of microbial suspensions. Data were compared with those obtainable from current commercial apparatus in terms of resolution and detection times. Trials with growing and non-growing cultures indicated periodic synchronous ion exchange processes. Media composition, particularly salt and nutrient ratios, remain crucial to early and rapid detection of viable microbial activity at low concentrations. With appropriate conditions very significant improvements in detection times with typical detection thresholds of 300 min for start concentrations of 10(2) are shown. It is concluded that with regard to resolution and stability, the system out-performs current systems and is superior in terms of potential test costs, sample handling and sample transport.

Biosensors & Bioelectronics

Review of Scientific Instruments, 1992

The change in electrical resistance during the chemical dissolution of one arm of a variable rati... more The change in electrical resistance during the chemical dissolution of one arm of a variable ratio potentiometric bridge under constant current conditions is shown to offer a high-precision, high-resolution method of determining depth and rate of etch in immersed alloy work pieces undergoing chemical milling. The method is stable and repeatable, displaying negligible interference of disturbances due to electrochemical or

Biosensors, 1985

Presently, few of the reported (bio)chemical sensor devices have found application in fermentatio... more Presently, few of the reported (bio)chemical sensor devices have found application in fermentation monitoring and control. Although many devices with desirable.