Showing papers by "Delft University of Technology published in 1968"
TL;DR: In this article, the authors used the uncorrected Kelvin equation to calculate cylindrical pore distributions from the desorption branch of nitrogen sorption isotherms with the aid of a corrected form of the Kelvin equation.
197 citations
TL;DR: In this paper, the authors extended the analysis of the adsorption branch of a nitrogen sorption isotherm to the model of spheroidal cavities, and the results of the cumulative calculations were shown to be satisfactory in appropriate cases.
161 citations
TL;DR: In this article, the curvature of the meniscus is dependent on the distance to the walls of the pore and taking into account this dependence leads to a different shape of the maniscus from the hemispherical shape generally assumed for cylindrical pores.
149 citations
TL;DR: In this article, the set of ordinary differential equations governing free convection boundary layer flow past an isothermal semi-infinite vertical flat plate is solved for large Prandtl numbers by means of the method of matched asymptotic expansions.
Abstract: The set of ordinary differential equations governing free convection boundary layer flow past an isothermal semi-infinite vertical flat plate is solved for large Prandtl numbers by means of the method of matched asymptotic expansions. The analysis leads to an expression for heat transfer which contains the Prandtl number explicitly and which is very accurate for sufficiently large values of the Prandtl number. On the other hand the analysis also has qualitative assets. Before choosing the mathematical method of solution, the physical aspects of the large Prandtl number free convection boundary layer are investigated. The mathematical solution serves to enlarge our understanding of the physical implications of a free convection boundary layer in a large Prandtl number fluid.
71 citations
TL;DR: In this paper, the influence of adsorption on capillary evaporation of nitrogen from slit-shaped pores is discussed quantitatively and the application of the corrected Kelvin equation to the calculation of pore-size distribution functions from nitrogen sorption isotherms is discussed.
68 citations
TL;DR: In this paper, simultaneous heat and mass transfer in laminar free convection at a vertical plate has been measured in the liquid phase, where an electrochemical method has been used for the mass transfer and the heat transfer was measured by differential thermal analysis.
25 citations
TL;DR: In this article, a cavity channel network consisting of many cavities with different compressibility interconnected by channels with different conductivity can serve as a model for a consolidating soil in both the primary and the secondary periods of consolidation.
Abstract: Synopsis A cavity channel network consisting of many cavities with different compressibility interconnected by channels with different conductivity canserve as a model for a consolidating soil in both the primary and the secondary periods of consolidation. The abundance of the constituting element is introduced as a continuous frequency function using the spring dashpot assembly as a model because it produces similar effects. It is shown how this frequency function can be determined from test results. Un reseau de cavites et de canaux comprenant de nombreuses cavites a compressibilites differentes reliees entre elles par des canaux a conductivites differentes peut servir de modele pour un sol de consolidation aux deux periodes, primaire et secondaire de consolidation. L'abondance des elements prenant part a la constitution est introduite comme fonction de frequence continue en utilisant l'ensumble a amortisseur comme modele parce qu'il product les memes resultats. On montre comment cette fonction de frequ...
23 citations
TL;DR: In this paper, it is shown that the magnitude of deviations from the common t curve depends on the particle size of Aerosil and that theoretical t values are in perfect agreement with the experimental ones.
15 citations
TL;DR: In this article, the attenuation of directional correlation due to finite solid angle of lens-spectrometers and sector field spectrometers was investigated and correction factors were calculated for angles from 90° to 180° and for entrance diaphragms of different size.
6 citations
TL;DR: In this paper, the authors show that polyallenes prepared with the aid of organoaluminum-VOCl3 catalysts appear in three distinct phases: two crystalline phases (I and II) and an amorphous phase.
Abstract: Polyallenes prepared with the aid of organoaluminum-VOCl3 catalysts appear to exist in three distinct phases: two crystalline phases (I and II) and an amorphous phase. Phase I shows two strong X-ray diffraction peaks at d = 5.62 A and d = 4.04 A; phase II has three strong peaks at d = 6.28 A, d = 5.03 A, and d = 4.21 A. The band of the amorphous phase has its maximum at about d = 5.6 A.
5 citations
TL;DR: In this paper, a more general formulation for velocity distribution function is given and the advantages of the present method are discussed in detail in comparison with other methods, particularly that of Shen.
Abstract: The main aim of the present paper is to give a more general formulation for velocity distribution function and in consequence the advantages of the present method are discussed in detail in comparison with other methods, particularly that of Shen. The method is then applied to the problem of plane linearized couette flow and the method of analysis is outlined. Moreover, the method seems to be suitable for non-linear cases. Further work on the applicability of the present method is in progress and it will be published soon.
TL;DR: In this article, a new theory was developed that predicts the sealing coefficient and the friction factor of a viscoseal under turbulent flow conditions, being a synthesis of Boon and Tal's laminar viscose aligner theory and Ng, Pan, and Elrod's turbulent lubrication theory.
Abstract: A new theory is developed that predicts the sealing coefficient and the friction factor of a viscoseal under turbulent flow conditions. This theory, being a synthesis of Boon and Tal's laminar viscoseal theory and Ng, Pan, and Elrod's turbulent lubrication theory, shows very satisfactory correlation with available experimental data. The results have been given in simplified formulas such that they are readily usable for design purposes. At high Reynolds numbers the seal geometry has been optimized, although performance near the optimum is rather constant for rather different values of the geometrical parameters. Existing theories on the turbulent behavior of the viscoseal are briefly discussed. Presented at the 23rd ASLE Annual Meeting in Cleveland, May 6–9, 1968.
TL;DR: In this paper, the three dimensional scattering of a plane and a spherical wave by an arbitrary smooth convex object was considered, and the authors considered the three dimensions of the plane and the spherical wave.
Abstract: In this paper the three dimensional scattering of a plane and a spherical wave by an arbitrary smooth convex object will be considered.
TL;DR: A new method is proposed to calculate the intersection points of two plane curves using the theory of singular points of a system of two differential equations to ensure that the singular point be stable.
Abstract: A new method is proposed to calculate the intersection points of two plane curves. The theory of singular points of a system of two differential equations is used in developing the method. The intersection point to be determined is identified with such a singular point and appropriate modifications are applied to the system to ensure that the singular point be stable, i.e. all integrals which start in the neighborhood of the singular point will always approach this point if the integral parameter tends to infinity. In addition a method is described for systematically searching for all intersection points in a prescribed rectangular area.
01 Oct 1968
TL;DR: In this paper, a simple frequency-selective circuit with an arbitarily high Q and a minimal sensitivity was proposed, which is made of an LC circuit and a special type of negative conductor.
Abstract: A simple frequency-selective circuit is proposed having an arbitarily high Q and at the same time a minimal sensitivity. Use is made of an LC circuit and a special type of negative conductor.