EMULSION COATING TO EXTEND POSTHARVEST LIFE OF MANGO (MANGIFERA INDICA CV. MANILA)

A coating emulsion was prepared using maltodextrins, carboxymethylcellulose, propileneglycol and a mixture of s orbit an fatty acid esters with an HLB of 6. The emulsion was sprayed on fully mature, unripened manila mangoes, which were the stored at 15 and 25C and 80–85% R.H. At 25C it was observed that rate CO² production increased and lost in control fruits after 12 days of storage. Coated mangoes kept their rate CO² production and suffered only 8% weight loss after 21 days of storage. After storage, the coating was washed out and fruits were allowed to ripen naturally, which occurred in 3–4 days. The results obtained from this study indicate that application of the hydrophobic coating extended the postharvest storage of mangoes for at least 20 days more than uncoated fruits.     

A PROCEDURE FOR THE OPTIMAL SYNTHESIS OF PLANAR MECHANISMS BASED ON NON-LINEAR POSITION PROBLEMS

The present paper describes a procedure for the optimal dimensional synthesis of mechanisms which is based on the solution of non-linear position problems. Planar mechanisms are modelled very easily by means of finite elements of bi-hinged rod type. The judicious choice of constraint conditions makes possible the solution of classical position problems: initial, finite-displacement, deformed and static-equilibrium problems, as well as the main types of dimensional synthesis: path generation, functions, rigid body guidance, mixed, and multiple. A single synthesis error function applies to all these types, and moreover is general since it is valid for mechanisms of any configuration. This function is based on the idea that the best mechanism for the given synthesis conditions is the one that least needs to be deformed when it is obliged to satisfy them exactly, to which end the elastic deformation of the elements is permitted. © 1997 by John Wiley & Sons, Ltd.     

ADAPTIVE PREDICTIVE CONTROL IN A THERMAL POWER STATION

This paper presents the summary application of an adaptive predictive control system (APCS) to the control and optimization of the processes in a coal power station. The results obtained, corresponding to a Research and Development project at the Pasajes de San Juan power station, which belongs to the company Iberdrola, demonstrate the suitability of the APCS application in this field as well as the important benefits that may be derived from it. © 1997 John Wiley & Sons, Ltd.     

Metastability of Tetragonal Zirconia Powders

The formation of metastable t -ZrO₂ by thermal treatment was studied in a systematic way on two different samples: a gel (G) and zirconyl acetate (A). The results show that initially nucle-ation of t -ZrO₂ is favored by creation of anionic vacancies with trapped electrons. At higher temperatures the electronic defects disappear, the crystallites grow, and the m -phase can nucleate. This evolution is observed perfectly on sample A because of its special morphological characteristics.     

Microbial Populations and Malolactic Fermentation of Apple Cider using Traditional and Modified Methods

The evolution of yeasts and lactic acid bacteria was examined during two methods of cider making: the traditional employed unwashed apples of different varieties and the modified used a sole washed acidic apple variety with temperature control during the cider making process. The alcoholic fermentation was carried out mainly by Kloeckera apiculata and Sacharomyces cerevisiae species, and their distributions were similar in the two methods. In the traditional, the malolactic fermentation proceeded at the same time as alcoholic fermentation and the “piqure lactique” occurred. In the modified method, no malolactic fermentation took place. In all musts, a fundamentally heterofermentative lactic flora was found, with Lactobacillus species most abundant in the traditional process.