3,126 research outputs found
Introduction
In the course of the nineteenth century the study of literature was professionalized. There was a concerted attempt to make the study of literature an academic pursuit, ‘a particular branch of learning or science’, to turn it into ‘literary studies’ or, as it was called in German, Literaturwissenschaft. 1 This attempt was ultimately successful in the sense that literary studies became a recognized and established discipline within the new Humboldtian kind of university. However, this success brought troubles of its own. Among other things, the arrival of the academic discipline of literary studies not only required a method of study but also a determinate field of study. In order to delimit such a field, a clear and well-defined concept of literature was needed. This meant that academic literary studies would have to transform, for its own specific purposes, such concepts as ‘literary work’ and ‘literary text’ as well as the concept of ‘literature’, from broad, vague, non-theoretical, everyday notions into something like well-designed theoretical tools. Though it has not always been recognized, this transformation has presented a major theoretical problem for literary studies, and it is arguable that to this day no satisfactory solution has been found
Transmission fluids for heavy-duty vehicles
In order to further improve the performance and efficiency of automatic power-shift transmissions for heavyduty applications such as trucks and construction equipment, transmission fluid development is an important activity. There are several different approaches on how to design and lubricate power-shift transmissions. With the correct selection of lubricant extended drain in combination with increased efficiency will result in a reduction of life-cycle cost, and at the same time reduce the environmental impact of the vehicles.
In this paper different transmission fluids, with a focus on ATFs, are presented together with some of their respective advantages and disadvantages. Fluid performance in several different areas such as shear stability, frictional performance and gear protection are presented. Also, industry trends in the ATF market regarding standards and product diversification are discussed from a global OEMs point of view, including information on Volvo’s approach to transmission oil specifications
Computational analysis of shock-induced flow through stationary particle clouds
We investigate the shock-induced flow through random particle arrays using
particle-resolved Large Eddy Simulations for different incident shock wave Mach
numbers, particle volume fractions and particle sizes. We analyze trends in
mean flow quantities and the unresolved terms in the volume averaged momentum
equation, as we vary the three parameters. We find that the shock wave
attenuation and certain mean flow trends can be predicted by the opacity of the
particle cloud, which is a function of particle size and particle volume
fraction. We show that the Reynolds stress field plays an important role in the
momentum balance at the particle cloud edges, and therefore strongly affects
the reflected shock wave strength. The Reynolds stress was found to be
insensitive to particle size, but strongly dependent on particle volume
fraction. It is in better agreement with results from simulations of flow
through particle clouds at fixed mean slip Reynolds numbers in the
incompressible regime, than with results from other shock wave particle cloud
studies, which have utilized either inviscid or two-dimensional approaches. We
propose an algebraic model for the streamwise Reynolds stress based on the
observation that the separated flow regions are the primary contributions to
the Reynolds stress.Comment: 33 pages, 23 figures, 3 table
Nonlinear Feedforward and Reference Systems for Adaptive Flight Control
Use of feedforward can alleviate feedback and adaptive actions. Feedforward signals can be generated from reference models and the same models can also be used as reference models in adaptive control. A method for designing the reference models is presented in the paper. By exploiting the structure of the equations describing air vehicles it is possible to find reference models that scale to the present flight condition and vehicle configuration. Such reference systems are derived for flying vehicles in a generic manner, suitable for both winged aircraft and missiles. The same type of reference systems are also used to create trajectories for feedforward signals that compensate known plant non-linearities
Cracks in turnout sleepers -- Conclusions from a questionnaire to the UIC Track Expert Group
To investigate the occurrence of cracks in turnout sleepers, how these were assessed and handled, a questionnaire was sent out to 15 members of the UIC Track expert group in December 2020. By February 20, 2021, eleven responses have been received. The responses are summarised and commented below
NON-INVASIVE VASCULAR VERY-HIGH RESOLUTION ULTRASOUND TO QUANTIFY ARTERY INTIMA LAYER THICKNESS : VALIDATION OF THE FOUR-LINE PATTERN
Preliminary findings suggest that very-high resolution ultrasound (VHRU, 55 MHz) could differentiate arterial intima layer thickness (IT) non-invasively in vivo. We aimed to validate ultrasound-derived IT measurements and describe a four-line pattern consistent with intimal thickening. VHRU was applied to temporal arteries of 37 patients with suspected giant cell arteritis without inflammation on histology. Anatomically matched ultrasound-derived measurements of arterial layer thickness with the leading-edge method was compared to histology. Intimal thickening (IT >0.06 mm on histology) was identified as a four-line pattern in VHRU with a sensitivity of 96.3% and a specificity of 100%. Histologic and VHRU IT measurement agreement was excellent (mean difference 0.007 mm; 95% limits of agreement, -0.043 to 0.057) and intra-class coefficient (ICC) 0.923 (95% confidence interval [CI], 0.833-0.964). Intra- and inter-observer agreements for VHRU IT were high: ICC 0.946 (95% CI, 0.877-0.976) and 0.872 (95% CI, 0.773-0.943). VHRU utilizing the leading-to-leading edge method allows accurate and reliable measurements of arterial IT in patients with IT >0.06 mm. Measurements of IT will provide the opportunity to explore early subclinical structural intimal changes in the arterial wall increasing with age. (C) 2019 World Federation for Ultrasound in Medicine & Biology. All rights reserved.Peer reviewe
Small-angle X-ray scattering and crosslinking study of the proteins L7/L12 from Escherichia coli ribosomes
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