7597 research outputs found
Sort by
Simultaneous electrolytic production of xylitol and xylonic acid from xylose
No full textA new electrocatalytic process for simultaneous electrolytic production of xylitol and xylonic acid or the corresponding xylonate salts directly from α-d-xylose in alkaline solutions of neutral salt as supporting electrolyte has been developed and presented. An electrocatalytically active cathode coating with essentially hydridic features has been employed to enhance Faradaic yields in xylitol production at low current densities by heterogeneous reaction of hydrogenation with H-adatoms, and the entire mechanism has been proved by experimental evidence. An anionic selective anodic coating for titanium substrate was also used to suppress oxygen evolution and optimize the xylonic acid production by direct oxidation with anodically generated bromine, and to carry out the electrode process at almost equilibrium potential. The kinetic effect of specifically adsorbable anions for decreasing cathodic current yields in xylitol production and the resulting necessity for membrane separation of catholyte from anolyte, with proper optimization of the supporting neutral salt composition, has also been emphasized
Svetsko tržište i jugoslovenska spoljnotrgovinska razmena poljoprivrednih i prehrambenih proizvoda
No full textThe first part of this article deals with the situation and changes in the world market of agricultural products. In the second part analysis is made of the position in foreign trade exchange of Yugoslav agriculture. Analysis is also made of the structure of turnover by sectors of goods for the whole agriculture and particularly for the sector 0 - food and live animals as the most important of them. Analysis is separately made of the trade balance of agriculture from 1986. to 1988.Prvi deo rada obrađuje stanje i promene na svetskom tržištu poljoprivrednih proizvoda. U drugom delu se analizuje stanje u spoljnotrgovinskoj razmeni jugoslovenske poljoprivrede. Izvršena je analiza strukture prometa po robnim sektorima za celu poljoprivredu, a posebno robnog sektora 0-hrane i žive životinje kao najznačajnijeg od njih. Posebno je analizovan i trgovinski bilans naše poljoprivrede od 1986. do 1988. godine
Informacioni sistem u poljoprivrednim preduzećima
No full textContemporary information systems and modern computer technology due to their advantages and usefulness play an ever important role in creating and carrying out business policy of agricultural enterprises. The application of contemporary information technology defines the role of informatics in business policy and business system. Information system of social agricultural enterprises encompasses a great number of information flows. For this reason it is necessary to determine those information necessary for certain levels of decision making. This may be accomplished if the competence of every manager in an agricultural enterprise are born in mind. A selection of information at different levels of decision making determines the competence in decision making and duplicating of information bearers is thereby avoided whereas at the same time the unification of data processing is enabled.Zbog svojih prednosti i koristi, savremeni informacioni sistemi i moderna kompjuterska tehnologija zauzimaju sve vidnije mesto u koncipiranju i vođenju poslovne politike poljoprivrednih preduzeća. Primena savremene informacione tehnologije definiše mesto informatike u poslovnoj politici i poslovnom sistemu. Informacioni sistem društvenog poljoprivrednog preduzeća sastoji se od velikog broja-tokova informacija. Stoga je neophodno utvrditi koje su informacije neophodne pojedinim nivoima odlučivanja. To je moguće učiniti ako se pođe od delokruga i nadležnosti svakog od rukovodilaca u poljoprivrednom preduzeću. Ovako izvršenom selekcijom informacija prema različitim nivoima odlučivanja tačno se utvrduje nadležnost u donošenju odluka i izbegava dupliranje nosilaca informacija, a time omogućuje i unificiranje obrade podataka
13C N.M.R. spectra of some 5-substituted-3-isopropyl-6-methyl uracils
No full text13C n.m.r. spectra of some 5-substituted-3-isopropyl-6-methyl uracils were determined in deuterated dimethyl sulfoxide (d6 - DMSO). The substituents are : H, Cl, Br, J, NO2, NH2, N(CH3)2, C6H5, C6H4-NO2-p and C6H4-NH2-p. It has been shown that 13C chemical shifts of C-5 of some of the examined compounds correlated linearly with the 13C chemical shifts of C-5 in the 5-substituted uracils as well as with the 13C chemical shifts of the substituted carbon in an analogues series of monosubstituted benzenes. The 13C chemical shifts of C-6 in some of the above compounds depend on the steric effects of the substituent in position 5 of the uracil ring
Comparison of possible phytotoxic metabolites in culture filtrates of the Diaporthe/Phomopsis complex of soybeans
No full textFilter-sterile culture filtrates of isolates of Diaporthe phaseolorum var. caulivora, Diaporthe phaseolorum var. sojae (anamorph Phomopsis sojae), and Phomopsis longicolla, causal agents of stem canker, pod and stem blight, and seed decay, respectively, on soybeans (Glycine max), grown on Czapek-Dox broth inhibited germination of soybean seeds (significant at P=0.05). Wilting and necrosis of excised soybean seedlings was significantly greater than the controls when treated with culture filtrates of P. longicolla and P. sojae. Soybean seedling radicle growth inhibited significantly when culture filtrates of P. longicolla were added
1H N.M.R. spectra of some 5-substituted-3-isopropyl-6-methyl uracils
No full textThe 1H n.m.r. spectra of some 5-substituted-3-isopropyl-6-methyl uracils were determined in deuterated dimethyl sulfoxide (d6-DMSO). The substituents are: H, Cl, Br, I, NO2, NH2, N(CH3)2, C6H5, C6H4-NO2-p and C6H4-NH2-p. It has been shown that relative chemical shift (Δδ) of N(1)-H proton of some of the examined compounds correlated linearly with Hammett σm constant for the substituents in position 5 of uracil ring. The correlation with the σm constant was interpreted as providing evidence that the inductive effect of the substituent on chemical shift is dominating one
Copper-deposited wire ion-selective electrode for the determination of copper(II)
No full textA wire ion-selective electrode was made by sulphiding electrolytic copper previously deposited on commercial copper wire. Sulphidation was carried out by means of gaseous hydrogen sulphide at an increased temperature. The electrode not only possesses good properties but it can also be coupled with an SCE to determine copper in potentiometric titrations with different complexing agents in both aqueous and non-aqueous solutions