Efficiency of nitrogen fertilizer in the sugarcane-vertical system in Guadeloupe according to growth and ratoon age of the cane

Sugarcane is one of the main economic resources of Guadeloupe (France). Cane grown on the island's vertisols shows nitrogen deficiency which is accentuated with each successive ratoon. This deficiency could partially explain the observed decrease in yield. The present study, based on the isotopic N method applied to different ratoons in the field, was aimed at: (i) diagnosing the problem in the crop environment itself; and (ii) quantifying the fertilizer-N balance. The results indicated that decrease in yield and N absorption by the cane was related to ratoon number. The real utilization coefficient for the fertilizer (RUC%) ranged from 6 and 34%, and a high proportion (30–40%) of fertilizer-N was immobilized in the soil (NiS%) after the annual crop cycle. The N absorbed by the cane was essentially derived from the soil. Rainfall at the beginning of (re)growth determined crop development and N supply to the crop. When the water requirements of the crop are satisfied, nitrogen supply and cane yield can be improved in two ways: (i) by increasing the efficiency of the applied N fertilizer (RUC% and NiS%); and (ii) by maintaining the soil's capacity to supply cane with N. This implies maintaining and, if necessary, upgrading the structural state of the vertisols.     

The Mutual Correlation of Glucose,Starch, and Beta-Glucan Release During Microwave Heating and Antioxidant Activity of Oat Water Extracts

Starch and beta-glucan are most abundant carbohydrate polymers available in oat products; however, their simultaneous release during extraction depends on morphological and processing conditions of raw material. The study analyzes the mutual correlation between the sample (oat flakes and bran) and treatment types (microwave heating (MW)—1–5 min; conventional heating (CH)—7 min) on water extract properties focusing on beta-glucan, starch, and glucose content as well as the antioxidant activity of water extracts. The strong negative partial coefficient correlation was found between solids-starch (??0.65) and starch-glucose (??0.89) content as well as DPPH (??0.66) antioxidant activity in oat flakes revealing the high release of glucose to the water phase and its prooxidant activity. For the oat bran, positive and very high partial coefficient was found for both glucose (0.98) and beta-glucan (0.98) content in solids while the mutual interaction between them was highly negative (??0.97), meaning the more beta-glucan, the less glucose in the water phase.     

Simulation of the process of scaling of tube heat exchangers

A semiempirical model of the process of deposit formation on the inner surface of heat exchanger tubes is obtained. By experimental investigation, constants of the scaling process that close this model are obtained for carbonate-type deposits.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 3, pp. 353–357, March, 1994.