Predicting Chemical Parameters of River Water Quality from Bioindicator Data

We address the problem of inferring chemical parameters of river water quality from biological ones. This task is important for enabling selective chemical monitoring of river water quality. We apply machine learning, in particular regression tree induction, to biological and chemical data on the water quality of Slovenian rivers. Regression trees are constructed that predict values of chemical parameters from data on the presence of bioindicator taxa at the species and family levels.     

Multigrid Convergence of Calculated Features in Image Analysis

This paper informs about number-theoretical and geometrical estimates of worst-case bounds for quantization errors in calculating features such as moments, moment based features, or perimeters in image analysis, and about probability-theoretical estimates of error bounds (e.g. standard deviations) for such digital approximations. New estimates (with proofs) and a review of previously known results are provided.     

Characterization and Optimization of a Resonant Cavity Enhanced P-i-N Photodiode Response

This paper presents linear pulse response of a Resonant Cavity Enhanced (RCE) P-i-N fotodiode. The RCE P-i-N photodiode designed for high-speed aplication is analysed for various submicron thicknesses of absorption layer, bias voltages, active areas and incident pulse optical excitations. The results are obtained by numerical simulation of the complete phenomenological model for two valley semiconductor. Great enhancement of the quantum efficiency and the product bandwidth-quantum efficiency, is obvious from obtained results for this photodiode type.     

Light backscattering polarization patterns from turbid media: theory and experiment

We present both experimental measurements and Monte-Carlo-based simulations of the diffusely backscattered intensity patterns that arise from illuminating a turbid medium with a polarized laser beam. It is rigorously shown that, because of axial symmetry of the system, only seven elements of the effective backscattering Mueller matrix are independent. A new numerical method that allows simultaneous calculation of all 16 elements of the two-dimensional Mueller matrix is used. To validate our method we compared calculations to measurements from a turbid medium that consisted of polystyrene spheres of different sizes and concentrations in deionized water. The experimental and numerical results are in excellent agreement.     

The effect of kinetic and hydrodynamic factors on current efficiency in the chlorate cell process

An equation has been derived which relates the current efficiency of chlorate production to the operational parameters of the process and the constants connected with the events in the diffusion layer of the anode. The latter have been estimated using available literature data and the equation has been tested for the temperature dependence of current efficiency by comparison with experimental results. A fair degree of agreement has been achieved.Partly presented at the XXth CITCE Meeting, Strasbourg 1969.     

Activation energy of isothermal martensitic β-α′ transformation

The kinetics of isothermal - martensitic transformation in the U–0.45 wt % Mo alloy has been investigated. The specimens were quenched from the region (690° C) and held isothermally at temperatures from 120 to – 196° C (liquid nitrogen). By quantitative metallographic methods the percentage of the newly formed-phase was determined and the half-thicknessc and radiusr of plates calculated. The activation energy for nucleation period was estimated. It was found thatG depends linearly on temperature. The nucleation rateN was determined to be a parabolic function of temperature. A part of the T-T diagram below theM _s temperature was determined.     

Electrochemical separation of phases in a copper alloy containing beryllium,nickel and zirconium

To determine the chemical composition of phases in a heterogeneous Cu-Be-Ni-Zr alloy, a 50% citric acid solution was used to permit selective electrochemical dissolution of the copper matrix from the second phase. Using the potentiostatic method it was found that quantitative dissolution of the copper matrix could be achieved at —250 mV (versus SSE). The method described for the separation of the copper matrix from the second phase could also be successfully applied to other heterogeneous copper alloys.     

Helical ordering of spins in a superconductor

The coexistence region of a superconducting phase and a helical ordering of localized spins is found within an isotropic model of free electrons and localized spins. Superconducting properties of this new phase are also studied. The experimental data regarding the superconducting-magnetic transition in ternary compounds are discussed.     

An analytical solution for the transient response in a diffusion cell of the Wicke-Kallenbach type

An analytical solution is developed for the problem of transient diffusion and first order reaction in a solid flanked by two well mixed fluid compartments. This solution is necessary and useful in describing unsteady-state measurements in a Wicke-Kallenbach diffusion cell or reaction studies in a single pellet reactor. It is shown that a proper choice of an inner product vector space, following the methodology developed by Ramkrishna and Amundson [14, 15], leads readily to the desired solution and guarantees its completeness. This solution is valid for the equivalent heat transfer problem also.     

Design characteristics of an aluminium-air battery with consumable wedge anodes

An attempt was made to optimize a mechanically rechargeable bipolar-cell battery, exemplified by an aluminium-air battery with self-perpetuating wedge anodes. The optimization involved current density of battery operation and some design parameters such as the anode thickness and the cell dimensions. It was shown that these parameters depend on the energy-to-power ratio selected by the user. The saline electrolyte aluminium-air battery was found to be essentially a low power-density/high energy-density power source. Energy densities of up to over 1500 W h kg^–1 are achievable for low power needs, indicating very long operations between recharging. It was also shown that aluminium should render significantly cheaper electric energy than any of the high-energy density metals.Nomenclature d anode plate thickness (cm) - d _p thickness of end-plates (cm) - d thickness of cell walls (cm) (see Fig. 1) - E energy density (W h kg^–1) - E _B total energy contained in the battery (k W h) - F the Faraday constant 26.8 A h mol^–1 - g _c weight of the air cathode per unit anode area (g cm^–2) - g _e excess electrolyte per unit electrode area (g cm^–2) - g _h weight of the hardware per unit anode area (g cm^–2) - g _m weight of metal per unit electrode area (g cm^–2) - _m g excess of unconsumable metal per unit electrode area (g cm^–2) - g ₀ sum of all the weights except that of consumable metal (g cm^–2) - g _ox weight of oxygen consumed withg _m (g cm^–2) - G total weight of battery (g) - G _m total amount of reserve metal per cell and per cm width (kg cm^–1) - G _m total weight of the wedges (kg) - G _r total weight of the reserve anode container except the metal (kg) - G free energy of oxidation of the metal (kW h mol^–1) - h _a height of the wedge (cm) - h _r reserve anode height (cm) - j current density (mA cm^–2) - J total current drawn from the battery (mA) - n number of electrolyte replacements between anode replacement - n _c number of cells in a battery - M atomic weight of the metal (kg mol^–1) - P power density (W kg^–1) - Q _e cost of metal in the cost of unit energy produced ($ kW^–1 h^–1) - Q _e ⁰ theoretical figure of merit of a metal ($ kW^–1 h^–1) - Q _m cost of metal per unit weight ($ kg^–1) - S _a total anode surface area (cm²) - U cell voltage without ohmic drop (V) - V cell voltage (V) - x width of battery (cm) - z number of electrons exchanged per atom of metal dissolved - interelectrode spacing (cm) - spacing between cover and top of a new reserve anode (cm) - _f material efficiency - _v voltage efficiency - _e conductivity of electrolyte (ohm^–1 cm^–1) - _e electrolyte density (g cm^–3) - _m density of metal (g cm^–3) - _p density of end-plates (g cm^–3) - _w density of cell-walls (g cm^–3)