Visible Spectroscopy of Irradiated High-Alkali Borate and Mixed-Alkali Phosphate Glasses

Expectations of increased stability for trapped electrons in high-alkali glasses, based on extrapolations from observations on low-alkali borate glasses, are not borne out. In 69Na₂O-31B₂O₃ glass, electron centers have approximately the same thermal stability as in Na₂O·2B₂O₃ glass. In Na₂Oplus;P₂O₅ glasses the lifetimes, 3 · 0.5 μS, of transiently trapped electrons as well as their absorption spectra prove to be independent of increase of Na₂O content from 50 to 60 mol%. The same composition change destabilizes "permanent" hole centers. Exchange of Na₂O with K₂O in the metaphosphate glass also has no effect on the trapped electron lifetime. Small linear shifts in the trapped-hole absorption peak wavelengths are observed in the latter case. The most important positive finding in the phosphate glasses is a pronounced mixed-alkali effect on the yield of transiently trapped electrons and holes and of permanently trapped holes. The yield is a minimum at Na:K=1:1, due either to the elimination of trap sites or to the reduction of alkali ion mobilities which play a role in trap formation.     

ENERGY CONSERVATION IN DRYING OF FRUITS IN TUNNEL DEHYDRATORS

This study reports the energy use and thermal losses associated with tunnel dehydrators and discusses methods of increasing energy efficiency. These dehydrators can operate with an efficiency of water removal greater than 50%. It is shown that energy conservation techniques such as minimizing air leakage, increasing air recirculation, utilizing a furnace heat shield to prevent heat losses, and maximizing input can result in significant energy savings.     

Production planning and control I. The decision problem

The application of the linear-quadratic-gaussian (LQG) tracking problem to production planning and control systems is discussed. Decision concepts are developed from an examination of the structure of a generalized production control system. The decision problem is modelled as a LQG tracking problem operating in the presence of persistent disturbances—the disturbances representing the demand for finished goods. The development of a solution leads to a linear, time-invariant decision policy which is a decomposition of the decision input into separate and nearly independent decision tasks. Sufficient conditions for the existence of a solution are presented. An open-loop, closed-loop decision system is presented to show how the decision model can be used to analyse relationships among system structure, performance, and information requirements.     

Calcium Bioavailability from Ripening Cheddar Cheese

Calcium bioavailability to rats was compared from CaCl₂ (28 mM), CaCO₃, fresh milk, milk adjusted to pH 5.35, and Cheddar cheese. The cheese was manufactured from pasteurized bovine milk and all doses were labeled extrinsically with ⁴⁵Ca and ⁴⁷Ca and administered orally to rats. One label (⁴⁵Ca) was added to milk before cheese manufacture and the other (⁴⁷Ca) was added to the cheese 24 h prior to dosing. Calcium bioavailability was determined by: 1) absorption measured by whole body counting, and 2) availability for bone metabolism assessed by bone radioactivity measurements. Calcium absorption averaged 76.8% and was not affected by length of ripening (p>0.05). Absorption from CaCl₂, CaCO₃, fresh milk, milk at pH 5.35, and the cheeses was similar. The two methods gave similar estimates of relative bioavailability. The ratio of ⁴⁷Ca absorption to ⁴⁵Ca absorption for any cheese sample was significantly greater than 1, indicating extrinsic labels added after processing may overestimate Ca absorption from cheese.     

Predictors of Beef Tenderness: Development and Verification

Equations were developed to predict beef longissimus dorsi (LD) tenderness after postmortem refrigerated aging. Warner-Bratzler shear force (WBSF) and myofibril fragmentation indices (MFI) were determined at 1, 3, 7 and 14 days postmortem on LD of Angus-Hereford (AH, n = 8) and 5/8 Brahman crossbred (n = 8) heifer carcasses. Correlation coefficients between WBSF and MFI were ?0.91, ?0.74, ?0.63, and ?0.40 at 1, 3, 7 and 14 days postmortem, respectively. None of the traits measured correlated significantly with 14-day WBSF (P > 0.05). A three-variable prediction equation that included 24-hr calcium-dependent protease (CDP) inhibitor activity, 0-hr CDP-I activity and 24-hr cystatin activity accounted for 63% of the variation in 14-day WBSF.     

Effects of Product Formulation, Processing, and Meal Composition on In Vitro Estimated Iron Availability from Cereal-Containing Breakfast Meals

The effects of breakfast cereal composition, breakfast cereal processing, and breakfast meal composition on relative iron availability from breakfast meals were estimated using an in vitro method. Addition of wheat bran and germ to cereals and meals reduced iron availability. Presweetening caused a slight increase in iron availability. Comparisons among meals containing cereals that were similar except for type of processing showed that processing may affect iron availability. Addition of orange juice to breakfast meals caused a dramatic enhancement of iron availability. Ascorbic acid fortified apple and grape juice increased iron availability but the effect was small compared with the orange juice effect. Studies with purified organic acids showed that ascrobic and citric acids present in the juices caused the observed enhancement of iron availability. Citric acid was a more potent enhancer than ascorbic acid.     

PORCINE LONGISSIMUS GLYCOLYTIC POTENTIAL LEVEL EFFECTS ON GROWTH PERFORMANCE, CARCASS, AND MEAT QUALITY CHARACTERISTICS

Animals (n = 72) with longissimus glycolytic potential (GP) values ranging from 113.8 to 301.1 μmol/g of tissue, were classified as having low (n = 24), moderate (n = 24), and high (n = 24) GP levels. Meat quality measurements such as longissimus ultimate pH and subjective color score decreased, while Hunter L* values, percentage drip loss and purge loss increased for animals classified as having either high or moderate GP levels compared to those with low GP values. Animals with higher GP had decreased longissimus protein content and improved taste panel tenderness scores and lower shear force indicating superior eating quality. Increasing aging time from 2 to 21 days decreased shear force and improved taste panel tenderness scores. These data indicate that both glycolytic potential level within the muscle and aging time can have significant effects on pork quality characteristics.     

A Text Creation Routine for Graphics on a Microcomputer

Placing text on the graphics screen in any size any angle is an important function of a graphics program. Some microcomputers, however, will not print characters on the graphics screen, and others have very limited ability, such as printing only in 40-character or 80-character mode. Characters are needed for dimensions and notes on the drawing as well as for prompts and messages. Alternate fonts, rotation of the text, and different sizes of text are needed for many applications, not to mention text that is scaled up and down as the user zooms in or out to magnify or reduce the size of the image. This article examines available techniques and discusses the advantages and disadvantages of each. A method is presented for producing stroke generated text by designing each character as a matrix of dots on a standard grid and storing the coordinates of the dots as endpoints of vectors to be used to draw the character. The standard grid is assumed to have its origin in the lower left corner and each coordinate is defined relative to that origin.     

Use of Tree and Graph Structures to Diagram the Logic of Large, Complex Programs

CADD software and other large, highly interactive, complex programs must keep track of many complex relationships and perform the correct operations with both speed and precision based on these relationships, which are often seemingly in conflict. Computers can evaluate only one relationship at a time and the relationships must be evaluated in a specified order that can vary greatly depending on the outcome of each test. Consequently, writing and debugging a program that will perform correctly under a wide variety of inputs can be a frustrating process that at times can seem to produce two "bugs" for each one that is corrected. Tree structures can be employed to maintain a dynamic diagram of the program structure as it is being created. Graph structures, which are closely associated with tree structures, can be employed to simplify the task of developing and implementing the correct program logic and to identify many of the design logic errors at an early stage.
This article describes the use of tree and graph structures to diagram program structure and logic for an educational CADD package that was written by the author.