Vol. 3 No. 2 (1964)

. By reacting zinc with methylene blue and thiocyanate and measuring the decrease in absorbance, calibration curve for a photometric determination of zinc are found, which under suitable conditions are independent of the pH, the ionic strength, the temperature, and also of small differences. Ichtisar. Djika seng direaksikan dengan biru metilena dan tiosianat dan diukur berkurangnja absorpsi, akan terdapat garis kalibrasi untuk suatu penentuan fotometris baru untuk seng, jang, djika dipenuhi sjarat2 tertentu, tidak terpengaruhi oleh pH, "ionic strength", temperature dan djuga tidak oleh…

. Let X1, X2, "¦..be a sequence of noncentral t-distributed random variables with parameter θ. In this paper we investigate the limiting behavior of density ratios of X0. This is an example of the family of distributions discussed in [4].Here, we derive the results of David and Kurskall [2] in a slightly more general form and a stronger result is obtained, namely: If θ1 < θ2 are two parameters and Rn(θ1,θ2) is the density ratio of Xn, then there is θ0 such that the limit of Rn is 0 with respect to θ<θ0 and is ∞ with respect to θ>θ0. With respect to θ=θ0, the limit infimum is 0…

. In this paper the changes of the orbital elements of stationary satellites due to meteor-impacts are discussed. From these changes in principle one should be able to draw the conclusion whether or not there exist a correlation between meteor-mass and velocity.It has been shown here, how to detect and estimate an increase in space-density and the velocity-vector of any meteor stream T which the satellite traverses. Numerical results, however, show that effects of meteor-impacts can be neglected at all.Ichtisar. Dalam tulisan ini diperbintjangkan, pengaruh pertumbuknja meteor2 pada satelit…

. At Dr. L. Perek

Ichtisar. Untuk memenuhi kebutuhan akan alumunium sulfat untuk pendjernihan air telah diselidiki pembuatannja dari tailing bauksit, suatu bahan bauksit inferieur jang merupakan zat buangan pada pertambangan bauksit. Tailing bauksit dihaluskan mendjadi "“100 mesh dan kemudian direaksikan dengan asam sulfat 45° Bé selama 3 djam pada 105-110°C. Sebagai hasil diperoleh suatu "cake" dengan 15,5% oksida2 logam jang dapat melarut, jang terdiri dari oksida alumunium dan besi III (Alumunium sulfat teknik mengandung 15-17% Al2O3). Zat 2 yang tidak melarut sebanjak 8,1 % (a.l. mengandung silica) tidak…