Showing papers by "Delft University of Technology published in 1971"
TL;DR: In this article, the longshore transport along a sandy beach resulting from the combination of a longshore current and waves is computed based on the principle that because of the waves the bed shear of the current is increased.
Abstract: The longshore transport along a sandy beach resulting from the combination of a longshore current and waves is computed. This computational procedure is based on the principle that because of the waves the bed shear of the current is increased. The bed load can be computed with any bed load formula (the formula of Frijlink which is commonly used at the Delft Hydraulics Laboratory is used in the paper), taking into account the previously mentioned effects of the waves. The transport in suspension is computed according to the procedure suggested by Einsgein. The influence of the assumed thickness of the layer in which the bed load is considered to take place and which determines the concentration of suspended material at the bed is presented. The results of measurements in a laboratory basin and along the coast of Queensland (Australia), are presented.
188 citations
TL;DR: In this paper, the authors set up and analyzed difference schemes for solving the initial value problem for the socalled Korteweg-de Vries equation, which implicitly contain the effect of dissipation.
Abstract: The purpose of this paper is to set up and analyse difference schemes for solving the initial-value problem for the socalled Korteweg-de Vries equation. After the discussion of a difference scheme which is correctly centered in both space and time, the construction of difference schemes which implicitly contain the effect of dissipation is described.
134 citations
TL;DR: In this article, Anderson et al. presented a study on fissure patterns in Cretaceous sediments of south-east England and reported on the geotechnical mapping of soils and sedimentary rock for engineering purposes with examples of practice from the Mangla Dam project.
Abstract: REFERENCES ANDREWS, J. T. & SMITH, D. I. (1970). Statistical analysis of till fabric: methodology, local and regional variability. Q. Jl geol. Sac. Lond. 125, 503-542. FOOKES, P. G. (1969). Geotechnical mapping of soils and sedimentary rock for engineering purposes with examples of practice from the Mangla Dam project. GLotechnipue 19, No. 1, 52-74. FOOKES, P. G. & DENNESS. B. (1969). Observational studies on fissure patterns in Cretaceous sediments of south-east England. GCotechnique 19, No. 4, 453-477. MATALUCCI, R. V., SHELTON, J. W. & ABDEL-HADY. M. (1969). Grain orientation in Vicksburg loess. J. sedim. Petrol. 39, No. 3, 969-979. MOON, A. T. (1970). A report on a study and analysis of fractures from the western end of the crystalline basement of the Aar Massif, Switzerland. B.Sc. thesis, Imperial College of Science and Technology, London. NORMAN, J. W. (1970). The photogeological detection of unstable ground. J. Instn Highs. Engrs 17, No. 2, 19-22. TCHALENKO, J. S. (1968). The microstructure of London clay. Q. JZ Engng Geol. 1, No. 3, 155-168.
85 citations
TL;DR: In this paper, the run-up of irregular waves which break on a slope is calculated by assuming that on the average the runup of each wave with a given height and period equals the run up of a periodic wave train of the same height and periods.
Abstract: Run-up of irregular waves which break on a slope is calculated by assuming that on the average the run-up of each wave with a given height and period equals the run-up of a periodic wave train of the same height and period. General expressions are derived for the distributions of the run-up and the wave steepness as functionals of an arbitrary joint distribution of the wave height and the square of the period. Explicit results are obtained for the case when these variates are jointly Rayleigh distributed with arbitrary degree of correlation. Some of the assumptions are verified by a comparison of the analytical results with previous experimental data.
77 citations
TL;DR: A kinetic study of substituent effects in the liquid-phase hydrogenolysis of benzyl oxygen compounds has been made using carbon-supported palladium as the catalyst in this article, where the effects of substitution in the aromatic ring were expressed in terms of a Hammett-Yukawa relationship with ϱ = −0.37 and −1.43.
76 citations
TL;DR: In this article, the reflection of a monochromatic plane electromagnetic wave by an electrically perfectly conducting grating is investigated, and the vectorial electromagnetic problem is reduced to two separate scalar problems: those corresponding to E- and H-polarization respectively.
Abstract: The reflection of a monochromatic plane electromagnetic wave by an electrically perfectly conducting grating is investigated. The vectorial electromagnetic problem is reduced to two separate scalar problems: those corresponding to E- and H-polarization respectively. A Green's function formulation of the problem is employed. For both cases an integral equation of the second kind for the remaining unknown function on the surface of the grating is derived. A numerical solution of this integral equation is obtained with the aid of either a (discrete) Fourier transform or a cubic spline approximation. Some numerical results of both the echellette grating and the sinusoidal grating are presented.
65 citations
61 citations
31 citations
TL;DR: The hypothesis is advanced that the gliding motility ofchromatium is caused by peritrichous bacterial flagella beating in a slime layer that surrounds the cell.
Abstract: Studies on cells harvested from the natural habitat showed thatA. oxaliferum is gram-negative and catalase-negative. Electron micrographs of carefully fixed cells revealed the presence of peritrichously arranged appendages with a minimum thickness of 90 A as well as capsular slime. The hypothesis is advanced that the gliding motility ofAchromatium is caused by peritrichous bacterial flagella beating in a slime layer that surrounds the cell.
30 citations
TL;DR: In this article, two batch techniques have been applied using the molecular sieve suspended in the reaction mixture at 0° or room temperature, where the outer surface of the sieve catalyzes the acetal formation whereas the inner surface selectively adsorbs the water formed.
Abstract: Acetals can be prepared in high yield from the corresponding aldehydes or ketones and alcohols using molecular sieves to shift the equilibria by adsorption of the water formed. Examples include acetals of acetone, cyclohexanone, iso-butyraldehyde, and benzaldehyde.
Two batch techniques have been applied using the molecular sieve suspended in the reaction mixture at 0° or room temperature.
The first method involves the use of dual-function proton-exchanged molecular sieves type Zeolon 500, AW 500, or mordenite. The outer surface of the sieve catalyzes the acetal formation whereas the inner surface selectively adsorbs the water formed.
According to the second procedure molecular sieve and catalyst p-toluene-sulfonic acid are added to the reaction mixture. In this case proton exchange between catalyst and sieve occurs which appeared to be fast with the molecular sieves types KA and NaA, much less pronounced with the types CaA, Zeolon 500, and AW 500. All these sieves however can be used because of the high rate of acetal formation. With KA and CaA essentially quantitative conversions are obtained within a few minutes.
27 citations
TL;DR: In this paper, a complete discussion of the mobility of the skew four-bar M 1, A 1, A 2, A 3, A 4 with spherical joints at A 1 and A 2 is given in terms of the parameters g, R1, R2, b and the angle α between a1 and a2.
TL;DR: The possible use of the phages and the defective phages for classifying B. subtilis strains into a number of groups according to their susceptibility to different phage and according to the presence of certain defective phage in the cells is discussed.
Abstract: When different techniques are used for the isolation of bacteriophages ofBacillus subtilis a number of different phages may be obtained. Furthermore defective phages are found in old cultures of all strains ofB. subtilis tested so far. The possible use of the phages and the defective phages for classifyingB. subtilis strains into a number of groups according to their susceptibility to different phages and according to the presence of certain defective phages in the cells is discussed.
TL;DR: In this article, the preparation and PMR investigation of some specifically deuterated t-butylcyclohexanes is reported, and the chemical shifts of the various ring protons and the vicinal axial-equatorial coupling constants have been determined accurately.
Abstract: The preparation and PMR investigation of some specifically deuterated t-butylcyclohexanes is reported. The chemical shifts of the various ring protons and the vicinal axial-equatorial coupling constants have been determined accurately. The coupling constants show that an equatorial t-butyl group distorts the chair conformation of cyclohexane: the t-butyl side of the ring is somewhat puckered. The chemical shifts of the ring protons of t-butylcyclohexane differ from those of cyclohexane. In consequence the use of a t-butyl group as a holding group in conformational analysis is not always justified.
A long range coupling of 1.4 Hz is observed between 1,3-diequatorial ring protons. This partly explains the complexity of the spectra of apparently simple spin systems of other cyclohexane derivatives.
The dehydration of 3-t-butylperdeuterocyclohexanol using D3PO4 gives rise to a mixture of the three t-butylperdeuterocyclohexenes. The intermediate formation of a protonated four-membered ring is proposed in order to explain the presence of deuterium in the t-butyl group of only 1-t-butylperdeuterocyclohexene.
TL;DR: In this article, a semi-empirical relationship for the structural weight of a wide range of subsonic aircraft is derived based on a generalized expression for the material required to resist the root bending moment due to wing lift in specified flight conditions.
Abstract: A semi‐empirical relationship is derived for the structural weight of wings, applicable to a wide range of subsonic aircraft. The method is based on a generalized expression for the material required to resist the root bending moment due to wing lift in a specified flight condition. Appropriate factors make the result applicable to cantilever and braced wings, for passenger and general aviation aircraft and for freighters. An assessment of the accuracy, based on actual wing weights of 46 aircraft, indicates that a standard deviation of 9·64 per cent is achieved. The weight formula presented allows for the effects of variations in the main wing dimensions and operational limits of the airplane and is therefore suited to parametric design studies.
TL;DR: In this article, the authors present a general procedure for designing a pipeline for the transport of a liquid, which is greatly influenced by the fact that the phenomenon of cavitation in a long pipeline is badly understood and experiments in this field are rare.
Abstract: When designing a pipeline for the transport of a liquid one of the problems to be considered is the provision of a device to guard against low pressures. These low pressures can be caused, for example, by a sudden pump failure. The failure creates a negative pressure wave which travels in the downstream direction. Vapor pressure may be reached at a particular point, after which cavitation may occur up a long part of the pipeline. After a certain time the cavitation vanishes causing a very high pressure which may damage the pipeline. In order to prevent the development of cavities and consequently the development of high pressures, a device like an air vessel or surge tank is built. The presence of these devices decreases the pressure waves considerably and increases the time scale af the system. This general procedure for designing a pipeline is greatly influenced by the fact that the phenomenon of cavitation in a long pipeline is badly understood and experiments in this field are rare.
TL;DR: MATHEMATICAL TOOLs from QUEUEing Theory are used to solve several problems of the traffic light system and some new characteristics are introduced describing the non-stationary behaviour of the light.
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TL;DR: The radioactive decay of 227Ra has been investigated with Ge(Li and Si(Li) detectors with the results of γγ coincidence experiments have been used in constructing a level scheme for 227Ac in this construction data known from the α-decay of 231Pa have also been used as discussed by the authors.
TL;DR: In this paper, a systematic investigation was made into the plastic behavior of pure iron and pure nickel at temperatures between 20 and 500°C and at strain rates ranging between about 5 · 102−104 sec−1.
TL;DR: Because of the internal powering of the fingers no additional volume is necessary and the prosthesis can be adapted to patients who have lost their fingers but still possess the palm of their hand.
Abstract: A new pneumatic powered, completely adaptive, hand prosthesis has been developed. Because of the internal powering of the fingers no additional volume is necessary and the prosthesis can be adapted to patients who have lost their fingers but still possess the palm of their hand. Other features are good prehension, low weight and high operating speed. A description of the construction is given, and the measured performance is discussed.
TL;DR: In this paper, the same authors presented an analysis of adsorption isotherms and isosteric heat data for various nonpolar gases on oxide, metal, salt and graphite adsorbents, and showed that the electric field emanating from the surface and/or the structure of the surface still strongly affects the molecular interactions in the higher adsorbed layers.
TL;DR: In this article, the α-γ angular correlations in the decay of 230U and226Th, involving the 2+ states in226Th and222Ra, have been studied using 230U sources prepared by evaporation of the activity on Al foils, and 226Th sources, prepared by collecting recoil nuclei from a230U source on Al foil.
Abstract: Perturbations of α-γ angular correlations in the decay of230U and226Th, involving the 2+ states in226Th and222Ra, have been studied using230U sources prepared by evaporation of the activity on Al foils, and226Th sources, prepared by collecting recoil nuclei from a230U source on Al foils. In vacuum, perturbation coefficients are found to be in agreement with the “hard-core-value” for static magnetic interaction. The perturbations in aluminum are found to be strongly dependent on the method of source preparation.
TL;DR: In this paper, a computer program which searches for new energy levels in a nuclear decay is described, making use of any of the following data when available: known level energies, spins and parities, alpha and beta feedings, transition energies and intensities, multipolarities, coincidence relations, and the Q -value of the decay.
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TL;DR: In this article, an attempt has been made to observe gamma-rays from the 3− level of the possible octupole band in222Rn occurring in the decay of226Ra.
Abstract: An attempt has been made to observe gamma-rays from the 3− level of the possible octupole band in222Rn occurring in the decay of226Ra. The gamma-ray energies already known in this decay have been measured with increased precision both in singles measurements and in coincidence with the 186-keV (2+ → 0+) transition.
TL;DR: In this article, the authors investigated the effect of frequency on the sensitivity and the temperature distribution of a hot wire to the ambient airflow, and provided a short review of some complicating factors not included in the linear theory.
Abstract: The aim of the investigation was primarily the computation of the dynamical corrections on the static calibration curve. A brief account is given of the available analytical expressions for the heat transfer of a hot wire to the ambient airflow. The appropriate form is inserted in the small perturbation energy equation giving, with constant values of the characteristic parameters, a linear second order differential equation. A number of numerical examples was computed from the exact solution yielding the influence of frequency on the sensitivity and the temperature distribution along the wire. The analysis is supplemented by a short review of some complicating factors not included in the linear theory.
TL;DR: In this article, a complex rearrangement on electron impact for β-aroyl-α-methylpropionic acids, involving both hydrogen and hydroxy migration followed by loss of carbon monoxide and allyl radical, is described and discussed.
Abstract: A complex rearrangement on electron-impact for β-aroyl-α-methylpropionic acids, involving both hydrogen and hydroxy migration followed by loss of carbon monoxide and allyl radical, is described and discussed. The rearrangement process, resulting in an ion [ArCOOH2]+, is favoured by electron-withdrawing substituents in the aromatic ring.
TL;DR: The question whether the second pbase of increased resistance after a B. pertussis injection reflects a developing celJ-mediated immunity cannot be answered with certainty, however, recent experiments have indicated that spleen cell suspensions from B.pertussis-treated donor mice, when transferred to recipients which are also given a small non-protective dose of the vaccine, can produce a state of adoptive resistance against Listeria infection.
Abstract: The question whether the second pbase of increased resistance after a B. pertussis injection reflects a developing celJ-mediated immunity cannot be answered with certainty. However, recent experiments have indicated that spleen cell suspensions from B. pertuss'is-treated donor mice, when transferred to recipients which are also given a small non-protective dose of B. pertussis vaccine, can produce a state of adoptive resistance against Listeria infection.
TL;DR: TheBacillus subtilus bacteriophages PBS 1 and 3 NT and the authors' own isolation I 10 are closely related with respect to morphological, physiological, biochemical and serological properties.
Abstract: TheBacillus subtilus bacteriophages PBS 1 and 3 NT and our own isolation I 10 are closely related with respect to morphological, physiological, biochemical and serological properties They are capable of carrying out generalized transduction The large diameter of the phage heads makes them suitable objects for the comparison of different electron microscopical techniques