1,734 research outputs found
Resisting the author: JT LeRoy's fictional authorship
No full textIn the last decade, the interest in the relation between author and text, author and autobiography, seems to have grown. In my article, I use the story of the author JT LeRoy as a framework to analyse what this growing interest means for our understanding of the word "author." JT LeRoy’s work was considered to be autobiographical or, perhaps, autofictional. However, the authorship of LeRoy appeared to be based on a hoax; JT LeRoy proved to be a fictitious persona, made up by the writer Laura Albert. How does the unmasking of an author influence the reception of his/her work? And what does it teach us about the relation between reader and text, reader and author? In my article, I attempt to answer these questions, and, furthermore, I discuss how LeRoy’s mixed gender relates to the question of the dead male author and the hyped "constructed" female author
On the orientational dependence of drag experienced by spheroids
No full textThe flow around different prolate (needle-like) and oblate (disc-like) spheroids is studied using a multi-relaxation-time lattice Boltzmann method. We compute the mean drag coefficient CD,ϕ at different incident angles ϕ for a wide range of Reynolds numbers ( Re ). We show that the sine-squared drag law CD,ϕ=CD,ϕ=0∘+(CD,ϕ=90∘−CD,ϕ=0∘)sin2ϕ holds up to large Reynolds numbers, Re=2000 . Further, we explore the physical origin behind the sine-squared law, and reveal that, surprisingly, this does not occur due to linearity of flow fields. Instead, it occurs due to an interesting pattern of pressure distribution contributing to the drag at higher Re for different incident angles. The present results demonstrate that it is possible to perform just two simulations at ϕ=0∘ and ϕ=90∘ for a given Re and obtain particle-shape-specific CD at arbitrary incident angles. However, the model has limited applicability to flatter oblate spheroids, which do not exhibit the sine-squared interpolation, even for Re=100 , due to stronger wake-induced drag. Regarding lift coefficients, we find that the equivalent theoretical equation can provide a reasonable approximation, even at high Re , for prolate spheroids.Accepted Author ManuscriptIntensified Reaction and Separation System
PENYELENGGARAAN VIRTUAL MEETING OPEN POLICY ASOSIASI PENYELENGGARA JASA INTERNET INDONESIA OLEH SHOW MANAGEMENT JT PRODUCTION
No full textDengan menggunakan metode penelitian kualitatif deskriptif yang bisa menggambarkan semua fenomena yang ada secara faktual dan sistematis. Teknik pengumpulan data yang dilakukan penulis adalah dengan melakukan observasi langsung selama kegiatan PKL di JT Production, studi literatur, dan wawancara kepada pihak penyelenggara. Penelitian ini menghasilkan beberapa hal yang dilakukan dalam penyelengaraan virtual meeting dari perusahaan Asosiasi Penyelenggara Jasa Internet Indonesia (APJII) yang dimulai dari planning berupa pengajuan, meeting dan survey, produksi konten, loading barang dan gladi bersih. Selain itu, sebagai show management, JT Production harus melakukan beberapa hal berupa pembuatan rundown, penghubung delegasi, desain, dan penentuan posisi dalam stage. Dengan adanya penelitian ini, diharapkan pembaca dapat mengetahui bagaimana pelaksanaan virtual meeting yang diselenggarakan oleh show management yaitu JT Production.
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By using descriptive qualitative research methods that can describe all the phenomena that exist factually and systematically. The data collection technique carried out by the author is by direct observation during Internship activities at JT Production, literature studies, and interviews with the organizers. This research resulted in several things being carried out in the implementation of virtual meetings from the Indonesian Internet Service Providers Association (APJII) company which started from planning in the form of submissions, meetings and surveys, content production, loading and rehearsals. In addition, as show management, JT Production have to do several things in the form of making rundowns, connecting delegations, designing, and determining positioning on the stage. With this research, it is hoped that readers can find out how the implementation of virtual meetings organized by show management, namely JT Production
Computer simulation of entanglements in viscoelastic polymer melts
No full textIn this thesis we report on computer simulations of polymer melts. Polymers in a melt can be viewed as long molecules which coil around each other and hinder each other’s motions: they are “entangled”. Entanglements occur because bonds between two adjacent atoms in a polymer chain can never be crossed by other such bonds. The goal of our study was to simulate and to understand the dynamical and rheological behavior resulting from this entanglement effect. Because of its relative simplicity, we have chosen polyethylene (PE) as our primary system of interest
Space-time coding with receive combiner bank for multiple-input-multiple-output system under multi-user cochannel interference
No full text[[abstract]]Space-time coding with receive combiner bank (STC-RCB), in which a bank of receive combiners is added before the space-time decoder for interference-plus-noise suppression, is proposed. Without loss of generality, the author consider space-time block code (STBC) to be the representative of STC and study the performance for (STBC-RCB). The author derive the output signal to interference-plus-noise ratio (SINR) (of the space-time decoder) for STBC-RCB under multi-user cochannel interference. By regarding STBC as a special case of STBC-RCB, the author also derive the output SINR for STBC under multi-user cochannel interference. Simulation results show that the output SINR of STBC-RCB can be much larger than that of STBC, also, they show that STBC-RCB can adopt the appropriate receive combining strategy in the RCB to further improve the performance.[[note]]SC
Hydrodynamic interactions and Brownian forces in colloidal suspensions: coarse-graining over time and length scales.
No full textWe describe in detail how to implement a coarse-grained hybrid molecular dynamics and stochastic rotation dynamics simulation technique that captures the combined effects of Brownian and hydrodynamic forces in colloidal suspensions. The importance of carefully tuning the simulation parameters to correctly resolve the multiple time and length scales of this problem is emphasized. We systematically analyze how our coarse-graining scheme resolves dimensionless hydrodynamic numbers such as the Reynolds number Re, which indicates the importance of inertial effects, the Schmidt number Sc, which indicates whether momentum transport is liquidlike or gaslike, the Mach number, which measures compressibility effects, the Knudsen number, which describes the importance of noncontinuum molecular effects, and the Peclet number, which describes the relative effects of convective and diffusive transport. With these dimensionless numbers in the correct regime the many Brownian and hydrodynamic time scales can be telescoped together to maximize computational efficiency while still correctly resolving the physically relevant processes. We also show how to control a number of numerical artifacts, such as finite-size effects and solvent-induced attractive depletion interactions. When all these considerations are properly taken into account, the measured colloidal velocity autocorrelation functions and related self-diffusion and friction coefficients compare quantitatively with theoretical calculations. By contrast, these calculations demonstrate that, notwithstanding its seductive simplicity, the basic Langevin equation does a remarkably poor job of capturing the decay rate of the velocity autocorrelation function in the colloidal regime, strongly underestimating it at short times and strongly overestimating it at long times. Finally, we discuss in detail how to map the parameters of our method onto physical systems and from this extract more general lessons-keeping in mind that there is no such thing as a free lunch-that may be relevant for other coarse-graining schemes such as lattice Boltzmann or dissipative particle dynamics
Hydrodynamic and brownian fluctuations in sedimenting suspensions.
No full textWe use a mesoscopic computer simulation method to study the interplay between hydrodynamic and Brownian fluctuations during steady-state sedimentation of hard sphere particles for Peclet numbers (Pe) ranging from 0.1-15. Even when the hydrodynamic interactions are an order of magnitude weaker than Brownian forces, they still induce backflow effects that dominate the reduction of the average sedimentation velocity with increasing particle packing fraction. Velocity fluctuations, on the other hand, begin to show nonequilibrium hydrodynamic character for Pe>1
Coarse-grained simulations of entangled star polyethylene melts
No full textIn this paper, a previous coarse-grain model [J. T. Padding and W. J. Briels, J. Chem. Phys. 117, 925 (2002)]10.1063/1.1481859 to simulate melts of linear polymers has been adapted to simulate polymers with more complex hierarchies. Bond crossings between highly coarse-grained soft particles are prevented by applying an entanglement algorithm. We first test our method on a virtual branch point inside a linear chain to make sure it works effectively when linking two linear arms. Next, we apply our method to study the diffusive and rheological behaviors of a melt of three-armed stars. We find that the diffusive behavior of the three-armed star is very close to that of a linear polymer with the same molecular weight, while its rheological properties are close to those of a linear chain with molecular mass equal to that of the longest linear sub-chain in the star
Design of stabilizing plate of JT-60SA
No full textThe stabilizing plate (SP) of JT-60SA has been designed based on an electromagnetic and a structural analysis. The SP plays a role of both a passive stabilizer of magnetohydrodynamics (MHD) instability and a first wall at low field side in combination with a graphite tile. The SP has a double skin structure with 10 mm thickness each in order to have simultaneously high resistivity in the toroidal direction and high strength against plasma disruption as well as a seismic event. A finite element method for the calculation of the electromagnetic force induced by disruption and the structural analysis has been applied. The most serious event which is fast major disruption, is mainly considered. The eddy current reaches up to 100 MA/m2, which induces electromagnetic force <120 MN/m3. The SP has been modified in order to satisfy the allowable membrane, bend and peak stress of SS316 L. Trial manufacture of a part of the SP has been done to investigate the effect of the weld on the deformation of the SP resulting from the contraction of the weld metal. The arrangement of heat sinks and coolant pipes, and graphite tiles has also been done, taking into account the long pulse operation of the JT-60SA plasma. 1. Introduction The project of JT-60SA [1] is in progress at Naka, Japan, as a satellite tokamak in the Broader Approach activity under the international collaboration between Japan and Europa. The JT-60SA tokamak, which is the largest superconducting device, was successfully completed in March 2020 and is in the commissioning phase, which is planned by May 2021, including the first plasma initiation. The purpose of JT-60SA is a demonstration and study of the steady-state plasma with high beta targeting on the supplement to ITER toward DEMO and contributing to optimizing ITER operation scenarios. After the commissioning phase, we will upgrade the JT-60SA tokamak for 26 months. We will install many in-vessel components such as in-vessel coils, lower divertor, a cooling system including a heat-sink for in-vessel walls, the stabilizing plate (SP), and additional heating systems. The SP plays a role of both a passive stabilizer of magnetohydrodynamics (MHD) instabilities such as vertical displacement event (VDE) and resistive wall mode (RWM), and the first wall at low field side in combination with a heat-sink as well as a graphite tile. The in-vessel metal wall whose purpose is the stabilization of MHD instabilities is installed in some tokamaks such as NSTX [2], KSTAR [3], EAST [4]. The principle of stabilization of MHD instabilities by the in-vessel metal wall is that eddy current induced by MHD instabilities produces a magnetic field that pushes plasma back and stabilizes MHD instabilities. The in-vessel metal wall named passive stabilizer plate surrounds the upper and lower region of the plasma at a low field side in tokamaks except for JT-60SA. The in-vessel metal wall called stabilizing plate in JT-60SA surrounds the whole region of plasma at the low field side to obtain the steady-state high beta plasma. Fig. 1 shows the bird’s eye view of the SP as well as a part of the vacuum vessel (VV), error field correction coil (EFCC), fast positioning control coil (FPCC), and resistive wall mode coil (RWMC) of JT-60SA. The SP can be toroidally separated into 18 sections and connected to the vacuum vessel by 74 pedestals which are equipped with 18 support frames. Fig. 2 shows the poloidal cross-section of the SP, the VV, lower and upper divertors in combination with the flux surface of the double- null divertor configuration of the JT-60SA plasma. The plasma does not attach but gets closer to the SP within a distance of 10 mm for effective MHD stabilization. The specification of the SP is listed in the Table 1. The material of the SP is stainless steel 316 L with low cobalt content (Co <0.05 wt%) to avoid the production of cobalt-60 which is a radioactive isotope and can be produced by the fission reaction with neutrons during deuterium-deuterium experiments. Fig. 3 shows the exploded view of one toroidal section of the SP. The SP consists of the main part of the SP as shown in Fig. 3a) and the support frame having * Corresponding author. E-mail address: [email protected] (S. Yamamoto). Contents lists available at ScienceDirect Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes https://doi.org/10.1016/j.fusengdes.2021.112361 Received 30 November 2020; Received in revised form 1 February 2021; Accepted 15 February 2021journal articl
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