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.     

Hygroscopic Coatings Control Surface White Discoloration of Peeled (Minimally Processed) Carrots During Storage

White discoloration on peeled carrots is partially due to surface dehydration which can be controlled with hygroscopic coatings: e.g., polyhydric alcohols and salt solutions. This study was performed at 2.5, 7.5, 10, and 15°C, using a model system controlling relative humidity at 33, 75 or 98% or a commercial system with low-density polyethylene (LDPE) plastic film bags. The moisture sorption properties of propylene glycol, sorbitol, glycerol and calcium chloride enabled them to keep the carrot surface moist and maintain a transparent surface layer through which the underlying orange color was visible. This effect was only observed at high relative humidities (e.g., 98% RH). Similar effects were observed on treated peeled carrots stored in LDPE bags. The moisturized appearance provided by the hygroscopic coatings during storage was effective at several different temperatures.     

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.     

Markoff chain modelling of NDI techniques

A procedure for non‐destructive inspection by taking into account the effects of stochastic fatigue crack growth is presented. For this purpose a Markoff chain model is used to update the crack statistics, allowing an efficient computational implementation and a clear account of the involved concepts. In this context, perfect and imperfect removal of cracks, respectively, are considered, which represent idealizations defining bounds for actual situations.