Elastic-Plastic Contact Damage in a Lead Lanthanum Zirconate Titanate

Spherical indenters were used to produce elastic-plastic contact damage in a lead lanthanum zirconate titanate (PLZT) under conditions of quasi-static and impact loading. The extent of radial cracking produced under both loading conditions showed good correlation with the response predicted by an earlier fracture mechanics analysis for quasi-static conditions. Calculated radial crack lengths corresponding to conditions of impact loading exhibited excellent agreement with experimentally measured values. The dynamic hardness of the PLZT was determined to be ∼ 1.5 times the quasi-static hardness. Differences in the radial crack lengths produced under the two loading conditions were attributed primarily to this difference in hardness response.     

DECOMPOSITION OF TURMERIC CURCUMINOIDS AS AFFECTED BY LIGHT,SOLVENT AND OXYGEN1

Turmeric curcuminoids are important natural pigments but their instability limits their use in many foods. This study was conducted to examine light-induced degradation of turmeric curcumin as affected by solvent system and oxygen. The rate constants and half-lives were determined for purified curcumin, demethoxycurcumin and bis-demethoxycurcumin exposed to 1450 lux using reversed-phase HPLC. Rates of degradation of each pigment followed first-order kinetics. Differences in rate constants and half-lives between the individual pigments were minor in an acetic acid-NaCl solution; however, in methanol, large differences in stability to light of the individual pigment were observed. Stability of all the pigments to light was several fold greater in methanol than in acid brine. In methanol sparged with air, stability to photooxidation was curcumin > demethoxycurcumin > bis-demethoxycurcumin. In methanol, curcumin was more stable than the other curcuminoids when sparged with air than when sparged with nitrogen. In methanol sparged with nitrogen, demethoxycurcumin was the most stable pigment. All of the pigments were stable in the dark.     

Experiments with stock control policies and leadtime setting rules,using an aggregate planning evaluation model of a make-for-stock shop

A simulation model, driven by real order time series, of an actual make-for-stock shop is described. A broad spectrum of different sets of decision rules has been incorporated in the model in an attempt to represent as many as possible of the production controls which might be utilized by a production manager. Experiments designed to determine the impact on a production cost function of changes in decision rules can be conducted over a wide range of conditions, with the objective of assessing the robustness of rule changes.

To illustrate the use of the model, the results of experiments in two areas of production control are presented. Changing the stock control policy used by the host company to a re-order level policy type was shown to lead to significant improvements in performance across the range of conditions examined, in the case of a low marginal cost of stock review. In experiments with leadtime setting rules, improvements in performance were obtained across the spectrum of experimental conditions when the leadtime distribution was altered to one based on batch work content and number of operations and the tightness of the mean leadtime was simultaneously increased.     

EFFECTS OF FOUR SPECIES OF BACTERIA ON PORCINE MUSCLE. 1. Protein Solubility and Emulsifying Capacity

SUMMARY– A technique was used to obtain aseptic porcine muscle, portions of which were inoculated with cultures of Pediococcus cerevisiae, Micrococcus luteus, Leuconostoc mesenteroides and Pseudomonas fragi. The inoculated samples were compared with aseptic controls throughout a 20-day storage period at temperatures of 2 and 10°C. All 4 organisms grew at 10°C, but only P. fragi and L. mesenteroides grew at 2°C. The solubilities of the various protein fractions were affected by inoculation treatment. This was exemplified by correlation coefficients ranging from —.37—0.50. The coefficients indicated the interrelationships affected by storage conditions and bacterial growth. Protein solubility studies revealed a loss in the water-soluble fraction during storage of the controls and the M. luteus- and L. mesenteroides- treated samples. Samples inoculated with P. fragi evidenced an initial loss, followed by an increase. The solubility of meat proteins in a salt solution increased during the first 8 days of storage, then decreased or remained relatively constant for all samples. In comparison with controls, samples inoculated with P. fragi increased in salt-soluble protein solubility during the first 8 days, whereas those inoculated with L. mesenteroides decreased during the latter part of storage. Insoluble protein generally increased except for P. fragi- inoculated samples, which decreased. Nonprotein nitrogen (NPN) increased for all treatments and controls during the 20-day storage period. NPN extracted from the samples inoculated with P. fragi increased greatly. The pH increased with growth of M. luteus and P. fragi and decreased with growth of P. cerevisiae and L. mesenteroides. The emulsifying capacity was not influenced by the growth of M. luteus or P. cerevisiae. However, the emulsifying capacity of samples inoculated with L. mesenteroides decreased, whereas that of samples inoculated with P. fragi increased.     

EFFECTS OF FOUR SPECIES OF BACTERIA ON PORCINE MUSCLE 2. Electrophoretic Patterns of Extracts of Salt-Soluble Protein

SUMMARY– Electrophoresis of 0.6 M KCI extracts of porcine longissimus dorsi muscle revealed little change in the type or number of protein bands found either by starch-urea or disc-urea gel electrophoresis. The 0.6 M KCI extracts of muscle samples inoculated with Pediococcus cerevisiae, Leuconostoc mesenteroides and Micrococcus luteus and stored at 2 and 10°C for 20 days did not differ electrophoretically from control samples. Extracts of samples inoculated with Pseudomonas fragi showed a loss in the number of protein bands on starch-urea gel and disc-urea gel electrophoresis, indicating this organism exhibited some proteolytic effect upon the myofibrillar proteins .     

Examples of high resolution visible to near-infrared reflectance spectra and a standardized collection for remote sensing studies

Abstract. A number of sets of high resolution (001 μm or better) spectra are described which span the major part to the visible short-wave infrared spectrum (0.4-2.5μm). These data sets include soils, both wet and dry, conventional agriculture, grasses, and shrubs, igneous and sedimentary rocks, minerals, and a variety of fabrics, building materials, and metals. Most are from the laboratory, some are field measurements. These collections do not include bi-directional reflectance data sets, nor limited domain (～0.4-l.0μm) visible near-infrared spectral data sets. To facilitate intercomparisons and spectral matching with remotely-sensed data such as the aircraft instrument (AVIRIS) a standardized collection is described in which all spectra are presented at 0.01μm intervals, in a common format. This collection is available for research studies on a PC diskette.     

Effect of Processing on Proximate Composition and Mineral Content of Sea Cucumbers (Parastichopus spp.)

The nutrient content, texture and holothurin content of two sea cucumber species were determined for fresh, dried and canned products. Fresh sea cucumber contained 89–91% moisture, 5–6% protein, 0.3% fat, 3% ash and 0.3% carbohydrate; dried sea cucumber contained 2–6% moisture, 61–70% protein, 2–3% fat, 16–24% ash, and 2–3% carbohydrate. Fresh sea cucumber contained 90 mg of holothurin per 100g of tissue. Canned sea cucumber contained moisture and protein levels similar to those generally found in marine finfish. Processing methods for canned sea cucumber resulted in a significant (P<0.01) decrease in potassium and increase in sodium. No significant differences (P<0.01) were found in the texture of canned products made from fresh-cooked, salted-cooked and cooked-dried raw material.     

Post-exsanguination Infusion of Ovine Carcasses: Effect on Tenderness Indicators and Muscle Microstructure

Lambs were assigned to 3 treatment groups: control (Ctr), infused with 10% volume (by wt) of a tenderizing blend (NCa), and NCa plus 0.015M CaCl₂ (WCa). Compared to Ctr and WCa, NCa-treated samples had lower shear force values (P < 0.05) and higher percent change in myofibrillar fragmentation index (P < 0.05). SDS-PAGE of infused samples revealed the appearance at 24 hr postmortem of 22-30 kd protein components. Scanning electron micrographs of NCa myofibrils showed they were more fragmented, fractured, or split and had wider interfibrillar spaces compared to Ctr and WCa. The fracture plane of muscles immediately postmortem was along the endomysial-sarcolemmal sheath, while at 24 hr postmortem the sheath was weakened enough for the fracture to occur along the surface of the myofibrils.