7,047 research outputs found
Center for low-gravity fluid mechanics and transport phenomena
Research projects in several areas are discussed. Mass transport in vapor phase systems, droplet collisions and coalescence in microgravity, and rapid solidification of undercooled melts are discussed
Numerical Approaches to Spacetime Singularities
This Living Review updates a previous version which its itself an update of a
review article. Numerical exploration of the properties of singularities could,
in principle, yield detailed understanding of their nature in physically
realistic cases. Examples of numerical investigations into the formation of
naked singularities, critical behavior in collapse, passage through the Cauchy
horizon, chaos of the Mixmaster singularity, and singularities in spatially
inhomogeneous cosmologies are discussed.Comment: 51 pages, 6 figures may be found in online version: Living Rev.
Relativity 2002-1 at www.livingreviews.or
Counterions and water molecules in charged silicon nanochannels: the influence of surface charge discreteness
In order to detect the effect of the surface charge discreteness on the
properties at the solid-liquid interface, molecular dynamics simulation model
taking consideration of the vibration of wall atoms was used to investigate the
ion and water performance under different charge distributions. Through the
comparison between simulation results and the theoretical prediction, it was
found that, with the degree of discreteness increasing, much more counterions
were attracted to the surface. These ions formed a denser accumulating layer
which located much nearer to the surface and caused charge inversion. The ions
in this layer were non-hydrated or partially hydrated. When a voltage was
applied across the nanochannel, this dense accumulating layer did not move
unlike the ions near uniformly charged surface. From the water density profiles
obtained in nanochannels with different surface charge distributions, the
influence of the surface charge discreteness on the water distributions could
be neglected
Research and Education in Computational Science and Engineering
Over the past two decades the field of computational science and engineering
(CSE) has penetrated both basic and applied research in academia, industry, and
laboratories to advance discovery, optimize systems, support decision-makers,
and educate the scientific and engineering workforce. Informed by centuries of
theory and experiment, CSE performs computational experiments to answer
questions that neither theory nor experiment alone is equipped to answer. CSE
provides scientists and engineers of all persuasions with algorithmic
inventions and software systems that transcend disciplines and scales. Carried
on a wave of digital technology, CSE brings the power of parallelism to bear on
troves of data. Mathematics-based advanced computing has become a prevalent
means of discovery and innovation in essentially all areas of science,
engineering, technology, and society; and the CSE community is at the core of
this transformation. However, a combination of disruptive
developments---including the architectural complexity of extreme-scale
computing, the data revolution that engulfs the planet, and the specialization
required to follow the applications to new frontiers---is redefining the scope
and reach of the CSE endeavor. This report describes the rapid expansion of CSE
and the challenges to sustaining its bold advances. The report also presents
strategies and directions for CSE research and education for the next decade.Comment: Major revision, to appear in SIAM Revie
IDENTIFIKASI MISKONSEPSI SISWA SMA KELAS X PADA MATERI MOMENTUM DAN IMPULS SETELAH PEMBELAJARAN INKUIRI BERBATUAN SIMULASI KOMPUTER
Miskonsepsi merupakan suatu konsepsi yang tidak sesuai dengan pandangan para ahli sehingga dapat menghambat siswa dalam mencapai tujuan pembelajaran Fisika. Miskonsepsi dapat terjadi pada berbagai materi Fisika seperti Momentum dan Impuls. Tujuan penelitian ini adalah untuk mengidentifikasi miskonsepsi siswa pada materi momentum dan impuls setelah pembelajaran inkuiri berbantuan simulasi komputer. Metode penelitian yang digunakan adalah metode pre-eksperimental dengan desain penelitian intact-group comparison. Penelitian ini dilakukan kepada siswa kelas X di salah satu SMA di kota Bandung yang dibagi menjadi dua kelompok, yaitu kelompok A yang terdiri atas 28 siswa (yang belajar menggunakan model inkuiri berbantuan simulasi komputer) dan kelompok B yang terdiri atas 30 siswa (yang belajar menggunakan pembelajaran konvensional). Instrumen yang digunakan untuk mengidentifikasi miskonsepsi siswa pada materi Momentum dan Impuls adalah Momentum and Impulse Four-tier Test (MIFT). Ditemukan bahwa konsepsi siswa terbagi menjadi lima kategori yaitu miskonsepsi, paham konsep, paham sebagian, tidak paham konsep, dan tidak dapat dikodekan. Persentase jumlah siswa yang mengalami miskonsepsi setelah pembelajaran inkuiri berbantuan simulasi komputer dan konvensional (ceramah) masing-masing 15,8% dan 33,8%. Miskonsepsi tersebar pada sub materi momentum, impuls, dan hubungan momentum dan impuls. Hal ini mengindikasikan bahwa penerapan model pembelajaran inkuiri berbantuan simulasi komputer lebih baik dalam memfasilitasi konsepsi siswa SMA kelas X pada materi Momentum dan Impuls. -----
Misconception is a conception which is not in accordance with the views of experts that can inhibit students in achieving the learning objectives of physics. Misconceptions can occur in a variety of physics materials such as momentum and impulse. The purpose of this study was to identify misconceptions students on the material momentum and impulse after computer simulations-assisted inquiry learning. The method used is pre-experimental with research design is intact-group comparison. This study was conducted to tenth grade students in one high school in Bandung who were divided into two groups: group a, which consists of 28 students (who learn to use computer simulations-assisted inquiry learning) and group b consisted of 30 students (who learn to use conventional learning). The instrument used to identify misconceptions students on momentum and impulse material is momentum and impulse four-tier test (MIFT). It was found that the student conception divided into five categories, that is misconceptions, sound understanding, partial understanding, no understanding, and no coding. The percentage of students who have misconceptions after computer simulations-assisted inquiry learning and conventional learning respectively is 15,8% and 33,8%. Misconceptions spread in sub material momentum, impulse and relation of momentum and impulse. This indicates that the application of computer simulations-assisted inquiry learning is better in facilitating the student conception on momentum and impulse materials
Active Brownian Particles. From Individual to Collective Stochastic Dynamics
We review theoretical models of individual motility as well as collective
dynamics and pattern formation of active particles. We focus on simple models
of active dynamics with a particular emphasis on nonlinear and stochastic
dynamics of such self-propelled entities in the framework of statistical
mechanics. Examples of such active units in complex physico-chemical and
biological systems are chemically powered nano-rods, localized patterns in
reaction-diffusion system, motile cells or macroscopic animals. Based on the
description of individual motion of point-like active particles by stochastic
differential equations, we discuss different velocity-dependent friction
functions, the impact of various types of fluctuations and calculate
characteristic observables such as stationary velocity distributions or
diffusion coefficients. Finally, we consider not only the free and confined
individual active dynamics but also different types of interaction between
active particles. The resulting collective dynamical behavior of large
assemblies and aggregates of active units is discussed and an overview over
some recent results on spatiotemporal pattern formation in such systems is
given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte
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