SPECTRORADIOMETRY AND COLORIMETRY IN THE LIGHTING INDUSTRY

Spectroradiometry is fundamental in the measurement and evaluation of color. It is used in the evaluation of new light sources, in the analysis of problem areas, and for the compilation of data for inclusion in the technical brochures describing lighting products. The basic elements of a spectroradiometer are described and the application of spectral-power distribution measurements to photometry and colorimetry is illustrated.     

USE OF ULTRAFILTRATION/REVERSE OSMOSIS SYSTEMS FOR THE CONCENTRATION AND FRACTIONATION OF WHEY

SUMMARY– Existing ultrafiltration/reverse osmosis technology provides a means of fractionating and concentrating cheese whey into liquid fractions containing a variety of protein: lactose ratios. These ratios may range from about 1:8 (raw whey) through 3:5 (a "skim milk equivalent") to 2:1 or higher. If a two- or three-stage ultrafiltration system were used with water injection between stages, a product with a protein:lactose ratio of 20:1 could be obtained. The exact protein:lactose ratio in the concentrate stream is a function of the permeability and selectivity characteristics of the membrane, and the system design and operating conditions. Some of the sanitation problems associated with the introduction of these new unit operations in the dairy and food processing industries are also treated at length.     

Trajectory control of a PUMA robot arm by inversion and servocompensation

Based on invertibility and functional reproducibility, an approach to the control of the PUMA arm with six rotational degrees of freedom is presented. The control system has two important features: (i) the ability for fast, precise trajectory tracking; and (ii) robustness to uncertainty in the system, such as variable payload, inertia, etc. The control law derived using invertibility gives decoupled, independently controlled responses in each joint angle using torquers. For robustness, a first-order servocompensator is designed for each decoupled inner loop driven by the joint angle error. For smooth joint angle responses, a command generator is constructed that produces the reference trajectories to be tracked. Simulation results are presented to show that rapid, accurate trajectory following is achieved in the closed-loop system in spite of large payload uncertainty.     

Optimal Hankel-norm approximation approach to model reduction of large-scale Markov chains

A model reduction problem of certain large-scale Markov chains under an optimal criterion for Hankel-norm approximation is discussed. The multi-dimensional Markov chain under investigation is assumed to have a finite-dimensional stationary state-transition matrix, which is first reformulated as a multi-input/multi-output (MIMO) linear time-invariant (LT1) stochastic system. Consequently, the resulting large-scale MIMO LTI stochastic system has a closed-form best approximant in the Hankel-norm from a specified class of stable lower-dimensional MIMO LTI systems.     

Design of reduced-order state estimators for linear time-varying multivariable systems

The design of reduced-order state estimators for linear time-varying multivariable systems is considered. Employing the concepts of matrix operators and the method of canonical transformations, this paper shows that there exists a reduced-order state estimator for linear time-varying systems that are ‘lexicography-fixedly observable’. In addition, the eigenvalues of the estimator can be arbitrarily assigned. A simple algorithm is proposed for the design of the state estimator.     

Subsolidus Compatibility in the System NaCl-KCl-AlCl3-NaF-KF-AlF3

The chemistry and properties of salts used as fluxes for recycling aluminum were studied. Many fluxing salts fall within the system NaCl-KCl-AlCl₃-NaF-KF-AlF₃, which has been shown to be a reciprocal system, with NaF-KCl, KC1-AIF₃, and NaCl-AIF₃ as the stable mixed-halide binaries. Twelve subsolidus compatibility tetrahedra were determined by X-ray analyses of samples heated in evacuated sealed tubes. X-ray measurements of quenched and annealed samples indicate that elpasolite, nominally K₂NaAlF₆, has a compositional range between 60 mo% Na₃AlF₆, 40 mol% K₃AlF₆ and 25 mol% Na₃AlF₆, 75 mol% K₃AIF₆. Improved X-ray powder data are given for KAIF₄, showing a previously reported structure to be essentially correct.     

INHIBITION OF LISTERIA INNOCUA AND L. MONOCYTOGENES IN A LABORATORY MEDIUM AND COLD-SMOKED SALMON CONTAINING LIQUID SMOKE

Five commercial liquid smokes were tested in vitro and the most inhibitory to Listeria monocytogenes ATCC 19115 and L. innocua ATCC 33090 was Charsol Supreme. Chum salmon samples (100-g each) were brined, dipped for 15 s at varying concentrations of liquid smoke, inoculated with L. innocua, cold-processed and analyzed. Liquid smoke concentrations of 60–100% reduced L. innocua by 3-log₁₀/g in the final product. Dwell times of 15 s to 5 min using 60% liquid smoke gradually decreased Listeria survival with an optimum 5-min dip. Isoeugenol was antilisterial in vitro but lacked synergism with liquid smoke in cold-smoked salmon. An immunoassay kit detected low inoculum levels (< 100 CFU/g) of L. innocua in one of three samples that were treated with liquid smoke for two and four minutes. Charsol Supreme was antilisterial but could not be relied on to totally eliminate Listeria in cold-smoked salmon. Panelists found the 0 to 2-min dipped sockeye salmon slightly desirable with no significant (p < 0.05) differences. The 5-min treatment was significantly (p < 0.05) darker, scored lower in desirability and flavor and contained 93 ppm of phenolic compounds.     

Optimization-based planning for the stochastic lot-scheduling problem

We describe a finite-horizon stochastic optimization model for the stochastic lot-scheduling problem and procedures for finding near-optimal solutions. Several different products are produced by a single-stage process with significant changeover times and costs, and the demand for these products is random. The deterministic version of this problem, the economic lot-scheduling problem, is the subject of a great deal of research. However, the problem with random demand for the products is commonly found in practice but is not as well researched. The models developed in this paper address the problem of dynamically planning the timing and size of production runs in this kind of production environment. We also report some computational results that indicate the quality of the resulting production schedules.     

Tensor Product Production System: a Modular Architecture and Representation

Can connectionist networks effectively represent and process structure? A technique called ‘tensor product representations’, which formalizes and generalizes the approaches of several previous connectionist models, was developed by Smolensky and shown to possess a number of desirable general properties. This paper shows how the technique can be effectively used to design a specific symbol-processing task: the serial execution of simple production rules requiring pattern matching, variable binding and structure manipulation. This ‘Tensor Product Production System’ is applied to one of the classes of production rules in Touretzky and Hinton's Distributed Connectionist Production System, and a number of comparisons are made between the two approaches. The mathematical simplicity and analyzability of the tensor product scheme allows the straightforward design of a simpler, more principled, and in some ways more efficient system.