Vízügyi Közlemények, 1961 (43. évfolyam)

4. füzet - IX. Képek a Föld különböző részeinek vízépítési munkáiról

(27 > Выведенные результаты единогласно определяют характерные для продолжительности засушливых периодов статистические закономерности и пригодны к тому, чтобы являлись основанием экономических расчетов, связанных с засушливыми периодами. Резюме автора переводила Борза Дэженэ инженер гидротехник DURATION OF DRY PERIODS By Dr. Z. Szigyártó (For the Hungarian text see pp. 183) For the purposes of this gaper, a dry period is understood as the longest duration of time beginning at an arbitrarily assumed instance t

0, during which no precipitation has fallen on the area investigated. With the above definition, the duration of dry periods on a characteristic region of the Great Hungarian Plains can be described by the following statistical relationships: All observation results gained annually for the duration of dry periods starting at a given date may be considered with fair approximation as a statistical sample, in which every element of the sample is an independent probability variable having the same distribution as the others. At the same time the duration of dry periods pertaining to two arbitrarily selected dates may also be regarded as an independent probability variable, provided that the first period is shorter than the time between the two. As far as Lhe type of the distribution is concerned it could be established, that the distribution of dry periods can be well approximated by an exponential distribution. The probable duration of the dry period was found finally to vary periodically during the year as a function of the date of beginning. This periodical fluctuation can well be approximated by a function consisting of a term having a semi-annual period and of one having an annual period: M (i) = a„ + г, cos (t - f

x)] + r

2 cos (/ - i

2)j where t should be substituted in days, and a

0, r

l

t r

2, /, and t.

z are constants. Thus the relationships derived determine in a positive manner the statistical laws characterizing lhe possible durations of dry periods, and are consequently suitable foundations for economy analyses relating lo dry periods. Author's summary translated by Z. Szilvássy struct, eng. V. TREATMENT OF SEWAGE IN THE DAIRY INDUSTRY By I. Biczó (For the Hungarian text see pp. 196) Industrial sewage purification should be a procedure connected with the operative technology. The aim is to reduce, respectively stop completely the hygienic and water system pollution by the waste matter contained in the utilized water, which is eliminated to a minimum by the technological arrangements. The quick decay of the basic material and by-producls of lhe dairy industry has helped to develop many sewage purification systems.