Joint inventory/replacement policies for parallel machines

In many manufacturing settings there is a significant cost associated with lost capacity due to machine failures. When this is combined with long lead times on the procurement of spare parts, it is often necessary to maintain inventories of critical machine components. Thus, the maintenance policy for the machines is inherently coupled to the inventory policy for spare parts. In this paper we identify and investigate the relationship between these two policies.     

2-(Hydroxymethyl)-N-nitrosothiazolidine-4-carboxylic Acid in Smoked Meats and Bacon and Conversion to 2-(Hydroxymethyl)-N-Nitrosothiazolidine During High-Heat Cooking

Concentrations of 2-(hydroxymethyl)-N-nitrosothiazolidine-4-carbox-ylic acid (HMNTCA) in a variety of smoked meats and bacon were determined by a newly developed method based on derivatization of HMNTCA with diazomethane and analysis by high performance liquid chromatography-thermal energy analyzer. Of samples analyzed, 4/8 raw bacon, 6/8 fried bacon, and 7/14 miscellaneous cured meat products contained 10–540 ppb of HMNTCA. Evidence suggested 2-(hydroxyrnethyl)-N-nitrosofhiazolidine in fried bacon likely originated by heat-induced decarboxylation of HMNTCA. Identity of HMNTCA in selected samples was confirmed by mass spectrometry.     

DEVELOPMENT OF A STATOR-CONTROLLED BRUSHLESS INDUCTION MACHINE WITH LEADING VAR CAPABILITY

ABSTRACT

The use of the DC-component of rotor current to continuously generate large amounts of reactive kVA from the stator of cage-rotor induction machines in which the total line current may be at a leading power factor, has been recently discussed [ 1-3 ] with initial test results from a 35 H.P. unit. The only constructional difference between these space-transient machines and conventional rotary motors is in the stator MMF layout which includes mixing of two wavelengths in operation simultaneously. The rotor current distribution is no longer sinusoidal but contains a series of harmonics similar to those present in a sheet-secondary linear induction motor with a pronounced longitudinal exit-edge effect at high speed. The development of the 35 and 150 H.P. machines which operate at unity power factor on 50?Hz is presented in light of the work performed earlier[4]to neutralize the exit-edge effect in a 17?kW LIM which attained an 80% terminal power factor at 50?Hz by the use of an asynchronous condenser winding of a second pole-pitch smaller than the main stator pole-pitch     

Direct measurement of hydraulic properties in developing berries of Vitis vinifera L. cv Shiraz and Chardonnay

Berries of Vitis vinifera L. cv Shiraz can undergo weight loss during later stages of ripening. Existing published views on how weight loss occurs are based on changes in capacity of the vascular system to import water during development (McCarthy and Coombe, Australian Journal of Grape and Wine Research, 5, 17–21, 1999). One important element of these views is the proposed cessation of water flow through the xylem after veraison. We have now measured the water flow into berries of Shiraz and Chardonnay as they develop using the pressure probe and the high pressure flow meter (HPFM). The pressure probe connected to the pedicel of individual berries provided measurements of single berry hydraulic conductance. By systematic excision of tissue segments of the berry and pedicel we determined where in the pathway hydraulic conductance changed during development. The HPFM was used on whole bunches showing that berries (including pedicels) represent parallel high hydraulic resistances and that the hydraulic resistance of the bunch axis was rather small. The hydraulic conductance per berry could be determined from excision experiments. There was close agreement between the pressure probe and HPFM measurements. Both showed a ten‐fold reduction in hydraulic conductance of whole berries from veraison to full ripeness. Shiraz had hydraulic conductances that were 2‐ to 5‐fold higher than those for Chardonnay. Shiraz maintained a higher hydraulic conductance past 90 days after flowering than Chardonnay. The decrease in hydraulic conductance occurred in both the distal and proximal parts of the berry for both varieties. The pressure probe also provided measurements of the xylem pressure that non‐transpiring berries could develop. These pressures were –0.2 to –0.1 MPa until veraison and increased to zero when the juice osmotic potential reached about –3 MPa in Chardonnay and –4 MPa in Shiraz. The results suggest values of the reflection coefficient of the osmotic barrier around the xylem vessels of about 0.1–0.2 at veraison decreasing to 0 at harvest. It is suggested that in addition to changes in xylem anatomy, aquaporins in berry membranes may play a role in regulating hydraulic conductance. Water movement from the berry back to the parent vine via the xylem (backflow) may be an important component of berry weight loss in Shiraz, particularly if the phloem ceases functioning at high osmotic potentials near maximum weight. Backflow could account for a weight loss of 43 mg per day in Shiraz berries for a relatively small gradient of 0.1 MPa.     

Comparison of Pond-Raised and Wild Red Drum (Sciaenopsocellatus) with Respect to Proximate Composition, Fatty Acid Profiles, and Sensory Evaluations

The proximate composition, fatty acid profiles, and the sensory characteristics of pond-raised red drum were compared to wild red drum. The proximate compositions and sensory characteristics were similar for pond-raised and wild red drum. The major difference between samples was in the fatty acid profiles. The pond-raised red drum had higher linoleic acid and lower docosahexaenoic acid concentrations than the wild fish samples. The eicosapentaenoic acid concentrations were similar in both pond-raised and wild red drum.     

Expert systems on microcomputers*

Abstract: The increasing popularity of expert systems has led to a demand to apply expert systems technology in a wide variety of computing environments. As a result, various efforts have been made to implement expert systems on microcomputers. This article reviews some of the ongoing work on tools for the development of microcomputer-based expert systems. Some specific application areas are noted, and a brief discussion of the advantages and disadvantages of implementing expert systems on microcomputers is presented.     

Mineral Binding Characteristics of Lignin, Guar Gum, Cellulose, Pectin and Neutral Detergent Fiber under Simulated Duodenal pH Conditions

Effective stability constants (K_cff) and amount of Fe bound by lignin, cellulose, guar gum, low and high methoxy pectin and NDF were determined under simulated duodenal pH conditions. Guar gum bound 8.4 μmol Fe per g fiber with the greatest affinity (K_cff= 6.27 × 10⁶) of any of the fibers studied; NDF, high methoxy pectin, and one of the binding sites of lignin bound 5.0. 5.0, and 19.5 μmol Fe, respectively. per g fiber, with a K_cff > 10⁵, and cellulose bound Fe so weakly that an effective stability constant could not be calculated. Lignin had two distinct binding sites for Fe, Zn, and Cu with the high affinity sites binding in the following order: Fe > Cu > Zn, but with twice as much Cu bound as either Fe or Zn.     

LEAD CONTENT OF FOODS STORED IN CANS AFTER OPENING

A study was conducted of the effect on the concentration of lead in canned foods when they are stored in their lead-soldered cans after opening. Lead concentrations were periodically monitored during 5 days or 14 days after can opening. Fruit juices had the greatest increases in lead concentration during storage. Low-acid foods did not exhibit a significant increase in lead concentration. Recommendations against storing acidic foods and juices in their opened cans are supported by the results of the study.     

New Method for Analysis of Trimethylamine Oxide Using Ferrous Sulfate and EDTA

In the analysis of trimethylamine oxide (TMAO) in fish tissues, an equimolar mixture of ferrous sulfate (FeSO₄) and disodium ethylenediaminetetraacetic acid (EDTA) (0.1 M) in acetate buffer (0.8 M, pH 4.5) was found to be a satisfactory replacement for titanium chloride (TiCl₃). The TiCl₃ method for TMAO was usually conducted at 80°C; the FeSO₄-EDTA reaction at 50°C appeared complete in 5 min and yielded comparable results. The use of an acetate buffer alleviated any interference from the trichloroacetic acid used for extraction of TMAO and trimethylamine (TMA) from fish tissue.