G. D. Robbing

Bio: G. D. Robbing is an academic researcher. The author has contributed to research in topics: Fast ion conductor. The author has an hindex of 1, co-authored 1 publications receiving 63 citations.

Electrolytic conductance measurements and capacitive balance

Abstract: In this paper the author reviews the principles of electrolytic conductance measurements, citing applications to molten salts and to solid electrolytes as well as to aqueous electrolytes.

Dc and ac conductivity in wide composition range Li2OP2O5 glasses

Abstract: The electrical conductivity of lithium phosphate glasses has been studied over wide frequency and temperature ranges, using a fully automated system capable of yielding data of high precision. Due to a “total drybox” sample preparation facility, samples containing P2O5 contents up to 65 mol% have been included without sacrifice of data quality. Comparisons with the behavior of the corresponding silicate, borate and boroaluminate glasses have been made and analyzed in terms of microscopic models. At the other composition extreme, measurements have been extended to 62.5 mol% Li2O without finding a conductivity maximum. The ac conductivity data have been analyzed using the modulus formalism, and systematic trends in the Kohlrausch parameter β with composition have been recorded. β decreases from 0.60 to 0.49 over the composition range 37–62.5 mol% li2O and seems to correlate best with the isothermal conductivity. Attention is drawn to anomalous structuring effects in P2O5-rich glasses.

Electrical Relaxation in Na2O·3SiO2 Glass

Abstract: The electrical relaxation associated with alkali diffusion in Na2O·3SiO2 glass was studied from 0.2 Hz to 700 kHz at –1° to 163°C. A formalism for analysis of electrical relaxation in conducting dielectrics which associates the nonexponential decay of the electric field to zero and the dispersions in the dielectric constant and the conductivity with a distribution of relaxation times for the electric field was developed and is shown to be in qualitative accord with current molecular theories of electrical relaxation in alkali silicate glasses. A relation between the dc conductivity, the limiting high-frequency dielectric constant, and the average electric field or conductivity relaxation time was derived and is verified experimentally for the Na2O·3SiO2 glass. The distribution of electric-field relaxation times for the glass is broad, asymmetric on a logarithmic scale, and weighted in favor of the shorter relaxation times; the distribution narrows with increasing temperature. A reduced electrical relaxation curve which can be used to compare electrical and mechanical relaxations in Na2O·3SiO2 glass was generated.

Effect of pressure on transport properties of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate.

Abstract: The self-diffusion coefficients (D) of the cation and anion in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) have been determined together with the electrical conductivity (κ) under high pressure. All three quantities strongly decrease with increasing pressure to ∼20% of their atmospheric pressure values at 200 MPa. D(PF6-) is always less than D([BMIM]+), despite the larger van der Waals volume of the cation. The pressure effect on the transport coefficients is discussed in terms of velocity correlation coefficients (VCCs or fij), the Nernst−Einstein equation (ionic diffusivity−conductivity), and the fractional form of the Stokes−Einstein relation (viscosity−conductivity and viscosity−diffusivity). It was found that the VCCs for the cation−cation, anion−anion, and cation−anion pairs are all negative and strongly pressure-dependent, increasing (becoming less negative) with increasing pressure. However, when the values of the VCCs for a given isotherm are normalized relative t...

Multi-analyte miniature conductance biosensor

Abstract: The fabrication and operation of a multi-analyte miniature conductance biosensor is described. The device responds to changes in the electrode double layer capacitance as the ionic strength is increased by the enzyme-catalysed generation of charged reaction products. Enzymes such as urease and l -asparaginase and a three-enzyme system consisting of urease, creatinase and creatininase were used to determine urea, l -asparagine and creatinine, respectively. Careful choice of suitable enzyme immobilization regimes led to device response times for the attainment of the steady state of the order of seconds. This fast response time allowed the construction of a flow cell with the incorporation of a urease-modified device for the continuous measurement of urea in flowing systems.

Parallel-wire probes for measurement of thick liquid films

Abstract: A method of calibration for parallel-wire film thickness probes is presented. This method allows calibration of probes made of fine wires with dimensions that are comparable to standard machining tolerances. The resulting probes yield accurate and continuous measurements of film thickness for thick (> 1 mm) films.