ECONOMIC ANALYSIS OF ALTERNATIVES TO MANUAL SORTING USING SELECTED ELECTRONIC GRADERS IN ASPARAGUS FRESH PACKING

Supplying quality fresh asparagus to the consumer begins with rapid handling at the fresh packing shed, which in turn requires a significant amount of labor. This study analyzed the effects of reducing the required labor by using selected electronic graders in the grading and sorting process of fresh asparagus packing firms. Four alternative electronic graders were considered by using two throughput scenarios of 680 and 880 kg/h with 25 people. The electronic graders generated labor savings in all cases. In the first scenario, substituting technology for labor produced modified internal rates of return (MIRR) of between 30 and 39%. All four graders in the second scenario had positive returns, with an MIRR range of 8 to 21%. The electronic graders have the potential to increase the profitability of fresh asparagus packing firms.     

Vacuum Infiltration of Polyamines Increases Firmness of Strawberry Slices Under Various Storage Conditions

Strawberry slices were vacuum infiltrated with polyamines and changes in firmness during storage were determined. Spermine and spermidine at 10 mM or 100 mM significantly increased firmness, whereas pu-trescine was not as effective at increasing firmness of slices stored at 1°C. The firming effect of the polyamines was similar to that of calcium chloride, and may have been due to their ability to bind to cell walls and membranes. In ripe receptacles of various cultivars which differed in firmness, putrescine (12–38 nmol/g fresh weight) and spermidine (19–33 nmoI/g fresh weight) were the predominant polyamines, while only low levels of spermine (<10 nmol/g fresh weight) were present. There was no discernible relationship between endogenous polyamine levels and fresh fruit firmness for the cultivars studied.     

The Covalent Reactions of Primary Amino Side–chains and Disulphide Bonds in Wool Keratin

The reactions with alkali of the disulphide bonds and the primary amino side–chains in wool have been investigated. Formation of dehydroalamine has been postulated and it has been conclusively identified in an alkali–treated, cystine–containing polypeptide. The mechanism of degradation of cystine in such a peptide has been further investigated and it has been shown that cysteine residues, produced from cystine during degradation, are also capable of degrading further to dehydroalanyl residues. The dehydroalanyl residues so produced are capable of reacting not only with other residues to form LAN and LAL, but also with other species present in the alkaline medium. The influence of amines on the cold setting of wool fibres with thioglycollates and on the dyeability of wool has been studied. Mechanisms are postulated to explain these effects.     

Preparation of Alkyl Esters of Pectin and Pectic Acid

Alkyl esters of pectin and pectic acid have been prepared via three different synthetic routes. Enhancements of intrinsic viscosity, binding to bile acids and to isolated soy protein were shown for these novel pectin derivatives. The development of new and improved pectin-containing products may be enhanced by the ease of preparation and improved functionality of such compounds.     

Portfolio performance of mutual funds: efficiency and robustness

Empirical analysis often mutual funds randomly selected from Jensen's study over a twenty-year period (1945-64) is used to test (l) the risk-return efficiency frontiers, and (2) the robustness in terms of minimax levels of variance. The statistical tests confirm that balanced funds and balanced portfolios are more robust than the so-called growth funds and growth portfolios. Tests on optimal ordering and selection of the best population also show that the mutual fund with the highest sample mean return has a very low probability of identifying the best population distribution, i.e. with a highest mean return     

Efficiency in public schools: a case study in non-parametric measurement

This study illustrates the problem of efficiency measurement in stochastic input-output systems when market price data are unavailable. Efficiency comparisons by non-parametric methods are attempted for selected public elementary schools in California for 1976-77 and 1977-78. A suitable linear programming model is developed for the efficiency frontier in the input-output space, which is found to be significantly different from an average relation. This is shown to have important policy implications for improving input performance for better efficiency.     

MELTING OF ICE AROUND A HORIZONTAL ISOTHERMAL CYLINDRICAL HEAT SOURCE

Processes during melting from a horizontal cylindrical heat source of uniform surface temperature embedded in ice have been studied experimentally. The volume of the melt and its shape were photographed at different times for various constant temperatures of the heat source. At early times and under all conditions, the melt occupied a cylindrical annulus. At later times free convective motion caused pear-shaped melt contours which pointed downward when the temperatures of the heat source were below 7°C and upward when the temperatures were above 8°C. Instabilities in cellular natural convection motion resulted in waviness of the interface. The location and magnitude of these ripples were found to depend on the temperature of the heat source and the melt layer thickness. Shadowgraph techniques were used to determine local heat transfer coefficients at the heat source surface.