2,909 research outputs found
Bridge-building : being the author\u27s original work, published in 1847, with an appendix containing corrections, additions & explanations suggested by subsequent experience, to which is annexed an original article on the doctrine of central forces / by S.
No full textConsists of the author\u27s "A work on bridge-building: consisting of two essays, the one elementary and general, the other giving original plans and practical details for iron and wooden bridges" Utica, N.Y. : H.H. Curtis, 1847, plus supplementary text, Notes in correction and explanation of the original text, and Central forces. Issued on a subscription basis by the author. Cf. initial p. iii. Issued on a subscription basis by the author. Includes errata list. Initial sequence i-iv in facsimile
Spectral properties of Andreev reflection from quantum turbulence in 3He-B: What do they tell about turbulent fluctuations?
No full textOne of the experimental techniques developed to measure quantum turbulence at low temperatures in 3He-B utilizes the Andreev reflection of thermal quasiparticle excitations from quantized vortices and vortex structures. We present the results of theoretical, numerical, and experimental study of Andreev scattering from quantum turbulence in 3He-B. We analyze the spectral properties of the Andreev reflection and compare these with the spectral properties of superfluid turbulence, and discuss the physical mechanisms responsible for the scaling of spectral densities. Finally, we discuss the relation between our findings and related observables in ordinary turbulence
I.A. Bunin and S.N. Durylin: problems of creative dialogue
No full textThe article is devoted to the consideration of the creative connections of I.A. Bunin and S.N. Durylin (1887-1954). In modern literary criticism, the question of studying the creative connections of S.N. Durylin and I.A. Bunin is urgent, which was not touched upon by the researchers. Although Durylin does not belong to the writers of emigration, in Russia he almost immediately finds himself in internal emigration: art works and scientific works were not published. This brought him closer to Bunin’s position. First of all, Durylin is interested in Bunin’s story “The Village”, in which the “Russian question” is touched. But, if in the story “Village” the writer does not fully accept the Bunin idea of Russia as a country of the wild and primeval, then in the “Life of Arseniev” the model of Russian life recreated by the author finds a response in Durylin’s creative consciousness. In the memoir book “In his corner” the author recreates the immanent image of Bunin’s native land. Brings together the writers of the perception of the revolution of 1917 as a “breakdown”, a catastrophe, a lyric narrative, a structureforming function of memory. However, if Bunin’s pre-revolutionary pictures of Russian life are the center of the narrative, then Durylin serves as a background (and a window into an ideal past), the focus of writers’ attention is the post-revolutionary process of the death of the healthy beginnings of Russian life, embodied in the form of snow
Seeing the world anew : the radical vision of Martin Waldseemüller's 1507 & 1516 world maps /
No full text9781929154470 (ISBN). 192915447X (ISBN). First edition 2012. Accompanied by 2 foldeds map in front and back pockets: 1507 map -- 1516 map.; Includes bibliographical references: pages 98-107.; Maps from pockets also available online http://nla.gov.au/nla.map-vn6254227; Original version of the 1507 map: Universalis cosmographiae secundum Ptholomaei traditionem et Americi Vespucii alioru que lustrationes. [St. Dié, France? : s.n., 1507]; Original version of the 1516 map: Carta marina, navigatoria Portugallen, navigationes atque tocius cogniti orbis terre marisque formam naturamq[u]e situs et terminos nostris temporibus recognitos et ab antiquorum traditione differentes eciam quor[um] vetusti non meminerunt auctores hec generaliter indicat / consumatum est in oppido S. Deodati compositione et digestione Martini Waldseemuller Ilacomili. [St. Dié, France? : s.n., 1516]. Prologue: In a Renaissance Vision, a Glimpse of the Modern / John W. Hessler -- "An island surrounded on all sides by sea" : The World Map, 1507 / John W. Hessler -- "Land of Cuba, part of Asia" : The Carta marina, 1516 / Chet Van Duzer -- Epilogue: A Renaissance That Resonates Still / John W. Hessler -- Notes -- Afterword / Ralph E. Ehrenberg -- About the authors -- Acknowledgments -- The Maps: The 1507 World Map, 12 sheets, with commentary -- Composite: front pocket -- The 1516 Carta marina, 13 sheets, with commentary -- Composite: back pocket
Improving patient safety in image-based procedures: Bridging the gap between preferred and actual proficiency
No full textFor patients less invasive image-based procedures (IBP) such as laparoscopy have many benefits in comparison to traditional open surgery, such as less pain, faster recovery, and fewer scars. However, to perform IBP effectively, efficiently, and above all safely, the surgical team is highly dependent on technology. The interaction with the surgical instruments and equipment requires extensive training. The proficiency level of the physician and the interaction with the instruments and equipment are key factors in ensuring quality of surgical performance in IBP and patient safety. During surgery, the surgeon should be able to concentrate on the therapeutic tasks. To achieve this, the gap between the preferred and actual level of proficiency of the physician should first of all be minimised by means of preclinical training using simulation tools. In this thesis, the validity of virtual reality simulators for training and assessment of basic psychomotor skills for laparoscopic surgery and flexible lower gastrointestinal endoscopy (colonoscopy) is established. The relation between different IBP skills was also investigated. The performance on two basic laparoscopy tasks (bimanual tissue manipulation and angled laparoscope navigation) proves to be not related; clinically-based expertise in laparoscopic tissue manipulation does not infer skilfulness in angled laparoscope navigation. Training in basic laparoscopy tasks does not affect performance of basic colonoscopy tasks (and vice versa). Training and assessment of basic IBP skills should thus focus on each IBP skill type independently. The influence of specific characteristics of the simulator interface on the efficacy of preclinical training on simulators was also studied. The angled laparoscope navigation task is performed better in an abstract virtual environment than in a virtual environment with simulated anatomic landmarks of the abdomen. And, for training of laparoscopic suturing tasks haptic feedback is a prerequisite. Furthermore, the quality of performance and patient safety should be better safeguarded by improving the interaction with the instruments and equipment in the operating room. Using an integrated operating room system together with the prototype of Pro/cheQ (a digital integrated procedural checklist tool) reduces the number of equipment and instrument related risk sensitive events further than using only an integrated operating room system.Industrial DesignIndustrial Design Engineerin
Versuch einer Beschreibung historischer und natürlicher Merkwürdigkeiten der Landschaft Basel : Von dem Author zum zweyten mahl aufgelegt / [Band I.]
No full text[s.c.
S.N. Maksudi and Russian Masons at the beginning of the XX century
No full textThe article investigates little-known facts in the life of the famous Tatar and Turkish public figure S.N. Maksudi – a turkologist, an educator, a deputy of the State Duma of the Russian Empire and the Majlis of the Turkish Republic at different periods of his life. At the beginning of the XX century a graduate of the Sorbonne University, a young lawyer, Sadri Maksudi, found himself at the center of the political life of the Turkic-Muslim world of Russia. He lived in St. Petersburg and was actively engaged in political activities. Just then he met Russian Freemasons and became a participant in the Masonic movement.The attitude towards Masonry in the Russian history is characterized by different assessments, for example, they were credited with participation in conspiracies, possession of secret knowledge, etc. In fact, most Masons were liberals who advocated the introduction of a wide range of democratic freedoms in Russia, including expanding the rights of national minorities. This attracted one of the leaders of Russian Islam, who actively defended the ideas of equality and enlightenment of his people.The article presents the analysis of the history of the opening of Masonic lodges in St. Petersburg after the revolution of 1905-1907 and their activities during the inter-revolutionary period, in which S.N. Maksudi took part.The purpose of the study was to analyze the views of the Tatar politician S.N. Maksudi through the prism of his participation in Masonic organizations of the early XX century. For this purpose the author used biographical, historical-genetic and historical-comparative research methods, as well as general scientific and dialectical methods of analysis. As a result, we came to the conclusion that despite all the objective differences between the social movement of Muslims in Russia and the teachings of the Freemasons, there were common ideological ideas between them, which attracted the Tatar-Muslim leader Sadri Maksudi to the ranks of the masons, which was reflected in his political life
Frequency reconfiguration of a dual-band phased array antenna with variable-impedance matching
No full textAccepted author manuscriptMicrowave Sensing, Signals & System
Phrenology proved, illustrated, and applied, accompanied by a chart ... together with a view of the moral and theological bearing of the science.
No full textWith : Synopsis of phrenology, and the phrenological developments. [s.l. : s.n., 1837]. Bound together subsequent to publication.Mode of access: Internet
Efficient Modeling of Rotational Effects for Wind Turbine Structural Dynamic Analysis
No full textThe history books of tomorrow will remember the start of this millennium by the global energy dilemma. The literature will portray the initial skepticism towards the first signs of global warming and the depletion of unsustainable energy sources. It will lay out how the evolution of mild symptoms into hard realities -such as the exponential increase in droughts, hurricanes and other natural disasters-drove these polarized opinions to a unified global belief that radical measures in energy policy needed to be taken. The accounts will continue by describing how the global discussion then moved to the implementation of sustainable energy alternatives. And they might explain how this drove the competition between solar and wind energy industries, which in turn pushed the development of their technologies. Even though dynamic substructuring might not star in those passages, I believe it will contribute to the technological evolution needed to sustainably meet tomorrow’s energy demand. This includes the field of wind turbines. Dynamic substructuring is in essence a linear structural dynamic analysis methodology that models a structure by the assembly of a set of substructure models, hence segmenting the normal linear model. By the implementation of this approach, components can be validated individually and reduction techniques can be tailored to the characteristics of and interaction between the components. Moreover, processing costs can be reduced via parallel computing and the ability to interchange component models without having to re-build the entire dynamic structural model. However, when operational analyses such as time integration are required and the model or its components are expected to undergo large rotations or displacements, the dynamic substructuring methodology needs to be integrated into a formulation that includes rotational effects, such as the floating frame of reference formulation (FFR). This formulation places the linear structure model into a floating reference frame. The body’s deformations within this frame remain linear, but the frame’s kinematic description is highly non-linear. This often leads to major reductions in processing efficiency, diminishing the competitive advantage that dynamic substructuring offers in comparison to other formulations. In the case of the operational analyses of multi-megawatt wind turbines on the other hand, rotation forces on the important turbine sub-systems tend to be relatively low. Hence the engineer’s gut feel leads to the belief that the floating frame of reference formulation can be significantly simplified. By (partly) linearizing the terms in this formulation, processing costs might significantly reduce at the loss of only little accuracy in the analyses. This leads to the main research question of this thesis: To what extent can the rotational effects be simplified for various wind turbine operational analyses without significantly impacting their dynamic characteristics? In order to answer this question, a simple wind turbine dynamic model is constructed in the floating frame of reference formulation. The terms in this formulation are subsequently simplified by various approaches and evaluated in terms of accuracy and processing costs in three different time simulations. This findings of the analysis will indicate which simplification approach will provide accurate results at minimal processing cost. The results indicate that the processing cost of the 2.3 megawatt turbine model can be reduced to less than one percent with respect to the reference model in steady operation, at negligible accuracy loss. In more transient cases, such as the simulation of startup or (emergency) shut down, the degree of simplification needs to be reduced to maintain the accuracy of the model. this leads to a smaller reduction in processing cost, now to twenty percent in of the original processing costs. The research demonstrates that the simplification of rotational effects in turbine models is feasible and has a significant effect on the processing times of the codes. The thesis hence recommends further development of the simplified FFR formulations. The formulations could be implemented into dynamic substructuring tools, allowing the analysis of operational dynamic interaction of a system’s subcomponents at competitive processing costs. Also, turbines of other sizes could be investigated, possibly leading to a presentation of the simplifications in non-dimensional form. In result, tailored simplifications of rotational effects can be applied to any wind turbine model. From the theoretical perspective the thesis recommends further research into simplifying the FFR formulations using other parametrization techniques, such as Euler parameters and Rodriguez parameters. These might pose new opportunities in terms of processing efficiency. The optimization of dynamic turbine modeling will contribute to speedier design iterations that result in more cost effective turbine designs. With a little bit of luck this industry might consequently turn wind into a leading global supplier of energy. And who knows, the odd history book might mention the contribution of dynamic substructuring to this process.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin
- …
