1,596 research outputs found
Good Words (Magazine) for 1868
No full textAs Abbey writes, the fable articles here precede and are different from their first appearance in book form a year later. For it was then that Ralston published the first edition of Krilof and His Fables. See my comments on the third (1871) and fourth (1883) editions. The book smells of its many years! The three fable articles are on 39-46, including six illustrations on 40-41; 215-221, including six illustrations on 216-17; and 413-20, including six illustrations on 416-17. These are magazine articles. They comment on Krilof's views and particularly on Russian foibles. Thus one prose text after another is integrated into the article. In the book, there will be, after a preface and a memoir, a simple collection of texts. In fact, the selection of Krilof fables within the article here is excellent, and the author puts them into a good cultural and political context. At least some of the illustrations are the same as those in the third edition.. The texts are close to those found in the published books. It makes sense to see the texts in the magazine here as forerunners of those fable texts there. I presume that Ralston had opportunity to edit and amend between his magazine articles and his book's first edition. The publisher of the magazine is of course the publisher of the third edition that I have. The print is minuscule! I needed a magnifying glass for normal reading. The index just after 774 assigns J.B. Zwecker and A.B. Houghton as illustrators for the eighteen illustrations in the three fable articles. Dalziel, Houghton, and Zwecker are the names I can make out on the illustrations. Dalziel is not mentioned on the title page, but there is reference to others.This is a hardbound book (hard cover)Norman MacLeod; W.R.S. Ralston for fable
Simple drag prediction strategies for an Autonomous Underwater Vehicle’s hull shape
No full textThe range of an AUV is dictated by its finite energy source and minimising the energy consumption is required to maximise its endurance. One option to extend the endurance is by obtaining the optimum hydrodynamic hull shape with balancing the trade-off between computational cost and fluid dynamic fidelity. An AUV hull form has been optimised to obtain low resistance hull. Hydrodynamic optimisation of hull form has been carried out by employing five parametric geometry models with a streamlined constraint. Three Genetic Algorithm optimisation procedures are applied by three simple drag predictions which are based on the potential flow method. The results highlight the effectiveness of considering the proposed hull shape optimisation procedure for the early stage of AUV hull desig
The use of computational fluid dynamics to assess the hull resistance of concept autonomous underwater vehicles
No full textAutonomous Underwater Vehicles (AUV’s) provide an important tool for collecting detailed scientific information from the oceans depths. The hull resistance of an AUV is an important factor in determining the powering requirements and range of the vehicle. This paper discusses the use of Computational Fluid Dynamics (CFD) to determine the hull resistance of three existing AUV’s, of differing shape and size. The predictions are compared with available experimental data and good agreement found. This work has demonstrated that with use of suitable shape parameterisation it is possible to carry out concept design evaluation using a RANS flow solver
The impact of placement method on Antifer-block stability
No full textThe main objective of this research was to assess the impact of different placement methods, with different packing densities, on the stability of double layered Antifer-block armour layers. This was done by experimental research in the wave-flume of the Fluid mechanics laboratory of the Faculty of Civil Engineering and Geosciences at Delft University of Technology. 17 experiments were performed with packing densities between 44.8 and 61.1 percent. For every experiment the under layer, toe and armour layer were rebuilt. The placed Antifer layer was tested with eight irregular wave series with increasing significant wave heights from 9cm up to 20cm. From these experiments followed that regular placement methods behave more stable than irregular placement methods with a similar packing density. Also the more irregular (less accurate) positioning of blocks within a regular placement method caused a decrease in stability. Higher packing densities for equal placement methods lead to higher stabilities and higher reflection coefficients. The resulting -values were between 4.0 and 23.7. If the reflection coefficients during the first wave series were high, this resulted in more overtopping during the latest wave series, which indicates that there is a positive correlation between the reflection and the overtopping. Overall it could be concluded that, when the under layer and the toe are smooth and the blocks can be placed accurately, the best performing placement methods are the closed pyramid placement method for packing densities around 45% and 50% and the double pyramid placement method for packing densities around 55% and 60%. The size of the openings to the under layer, of the double pyramid placement method, influenced the reflection coefficients. When the second layer was shifted half a nominal diameter upwards the reflection coefficients were minimal. It is recommended to investigate the possible negative influence of oblique incoming waves on the stability of the double pyramid placement method. The eventual choice of the placement method and packing density depends on the allowed reflection and/or overtopping and the construction costs. The construction costs can be divided into the production costs, the placement costs and the constant costs. For equal constant costs and equal or small differences in placement costs the placement with the higher packing density and accompanying stability value is cheaper for high design wave heights. When the placement costs decrease for both placements or only for the placement with the higher packing density, then the placement with the higher packing density becomes also cheaper for lower wave heights.Civil Engineering and Geoscience
The simulation of free surface flows with Computational Fluid Dynamics
No full textComputational fluid dynamics is a powerful and versatile tool for the analysis of flow problems encountered in themaritime environment. The University of Southampton Fluid-Structure Interactions research group use ANSYS CFX tomodel a wide variety of flow problems; to gain insight into flow physics, improve designs and increase the efficiencyand safety of marine vehicles. A series of three case studies from on-going research looks at: loads applied on liquefiednatural gas tanks due to sloshing, slamming pressures experienced by high speed craft as well as the influence ofpropellers on the resistance characteristics of autonomous underwater vehicles. The presence of the free surface,complex shapes and the unsteady nature of these applications make their simulation with computational fluid dynamicsparticularly challenging. The successful validation of the computational models has resulted in the development of aselection process for suitable multiphase models as well as cost-effective meshing strategies
Author Correction: Attosecond angular streaking and tunnelling time in atomic hydrogen
No full textCorrection to: Nature, 568, pp. 75–77 (2019), https://doi.org/10.1038/s41586-019-1028-3, published online 18 March 2019.
In this Letter, the statement ‘I.I. and A.B. performed their computations at the NCI Australia’ was missing from the Acknowledgements section. The original Letter has been corrected online.No Full Tex
Jeff Rasley; Trekker, Author
No full textJeff, the author of Bringing Progress To Paradise, is a graduate of the University of Chicago 1975, A.B. magna cum laude, Phi Beta Kappa, All-Academic All-State Football Team and letter winner in swimming and football; Indiana University School of Law 1979, J.D. cum laude, Moot Court and Indiana Law Review; Christian Theological Seminary 1988, M.Div. magna cum laude, co-valedictorian and Faculty Award Scholar. Rasley was admitted to the Indiana and U.S. District Court Bars in 1979 and later to the U.S. Supreme Court Bar. He practiced law in Indianapolis for thirty years. Rasley is currently partner in Knowledge Capture Publishing and editing, president of the Basa Village Foundation USA Inc. and U.S. liaison for the Nepal-based Himalayan expedition company, Adventure GeoTreks, Ltd. He teaches classes for IUPUI Continuing Ed. Program and Indiana Writers Center. He is an avid outdoorsman and recreational athlete. He leads trekking-mountaineering expeditions in Nepal and has solo-kayaked around several Pacific island groups. Rasley also loves to read and considers completing Marcel Proust’s 3600 page Remembrance of Things Past as one of his most enjoyable accomplishments. Rasley is married to Alicia, who is a multi-published author, RITA Award winner, and University professor
RRAM Crossbar-Based Fault-Tolerant Binary Neural Networks (BNNs)
No full textComputation-In Memory (CIM) using RRAM crossbar array is a promising solution to realize energy-efficient neuromorphic hardware, such as Binary Neural Networks (BNNs). However, RRAM faults restrict the applicability of CIM for BNN implementation. To address this issue, we propose a fault tolerance framework to mitigate the impact of RRAM faults on the accuracy of CIM-based BNN hardware. Evaluation results using MNIST, Fashion-MNIST and CIFAR-10 datasets demonstrate that the proposed framework outperforms the related works as it restores more than 99% of the RRAM fault induced accuracy reduction with relatively less overhead.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Computer EngineeringQuantum & Computer Engineerin
Shear settling in laminar open channel flow: analytical solution, measurements and numerical simulation
No full textIn beaching of tailings, sand and clays may segregate. In laminar flow this is due to shear settling. First implementations of shear settling in numerical flow models are seen, offering unprecedented potential to conduct tailings management studies. In order to validate numerical codes, reference materials are necessary. For laminar flow, there is a small set of flume tests available from an earlier study. An analytical solution for transient sand concentration profile development with distance in laminar open channel flow appeared recently. This analytical method is more complete than an analytical model developed earlier at the author’s institute. Data and analytical solutions are analysed and applied to serve for the validation of numerical flow simulation of beaching in tailings storage facilities. Fair agreement is observed between measurements and the analytical method. Moreover, fair agreement is obtained between an earlier produced computational outcome of the numerical model Delft3D-slurry and analytical solution. This contributes to building confidence in this model as an aid in supporting tailings deposition management.Offshore and Dredging Engineerin
Experimental study on the development of abrasion at offshore concrete structures in ice conditions
No full textConcrete structures in marine environments subject to sea ice interaction are at risk of erosion and damage. Industry is interested in characterizing the ice abrasion phenomenon so that abrasion risk can be managed. The experiments conducted in this work have an exploratory character in order to identify the abrasion phenomenon and qualitatively observe the corresponding processes. The tests are a simulation of micro scale ice-structure interaction and involve the translation of concrete samples while subject to lateral impingement of conical ice samples. Loads in both axes are measured so that tangential and normal force relationship can be examined while the ice samples are catastrophically crushed. The paper divides the interaction into abrasive loading regions and loading orders intentionally to facilitate analysis of the abrasion process. The wear of the concrete surface is described using visual observation and surface feature measurements Concrete of varying mixtures has been examined and the effects on the concrete surfaces from repeated static ice-bonding and bondbreakage is analysed.Master Offshore and Dreding EngineeringMaritime and Transport TechnologyMechanical, Maritime and Materials Engineerin
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