27,087 research outputs found
Concurrent coupling of atomistic simulation and mesoscopic hydrodynamics for flows over soft multi-functional surfaces
We develop an efficient parallel multiscale method that bridges the atomistic
and mesoscale regimes, from nanometer to micron and beyond, via concurrent
coupling of atomistic simulation and mesoscopic dynamics. In particular, we
combine an all-atom molecular dynamics (MD) description for specific atomistic
details in the vicinity of the functional surface, with a dissipative particle
dynamics (DPD) approach that captures mesoscopic hydrodynamics in the domain
away from the functional surface. In order to achieve a seamless transition in
dynamic properties we endow the MD simulation with a DPD thermostat, which is
validated against experimental results by modeling water at different
temperatures. We then validate the MD-DPD coupling method for transient Couette
and Poiseuille flows, demonstrating that the concurrent MD-DPD coupling can
resolve accurately the continuum-based analytical solutions. Subsequently, we
simulate shear flows over polydimethylsiloxane (PDMS)-grafted surfaces (polymer
brushes) for various grafting densities, and investigate the slip flow as a
function of the shear stress. We verify that a "universal" power law exists for
the sliplength, in agreement with published results. Having validated the
MD-DPD coupling method, we simulate time-dependent flows past an endothelial
glycocalyx layer (EGL) in a microchannel. Coupled simulation results elucidate
the dynamics of EGL changing from an equilibrium state to a compressed state
under shear by aligning the molecular structures along the shear direction.
MD-DPD simulation results agree well with results of a single MD simulation,
but with the former more than two orders of magnitude faster than the latter
for system sizes above one micron.Comment: 11 pages, 12 figure
Counting pebbles wasn\u27t even a class in high school: seeing visual arts education through a process-forward lens
This thesis explores process-forward visual arts education in the Greater Providence arts education community. The researcher conducted interviews with arts educators as well as administrators working within organizations guided by a “process-forward” philosophy. Interview transcripts are analyzed to identify any emergent themes of intended and actualized student learning outcomes as well as other commonalities which exist among the interviewed organizations. This investigation found that, within these organizations, multiple, significant forms of student learning outcomes were identified that extended well beyond any particular aesthetic merits of the artistic products created by students
The author calls, in this thesis, for a recalibration and expansion of existing methods of assessing visual arts learning in order to take greater account of process-forward learning outcomes, which will, the author argues, provide a much more comprehensive view of what students gain through engaging in the visual arts
Transverse Spin Structure of the Nucleon through Target Single Spin Asymmetry in Semi-Inclusive Deep-Inelastic Reaction at Jefferson Lab
Jefferson Lab (JLab) 12 GeV energy upgrade provides a golden opportunity to
perform precision studies of the transverse spin and
transverse-momentum-dependent structure in the valence quark region for both
the proton and the neutron. In this paper, we focus our discussion on a
recently approved experiment on the neutron as an example of the precision
studies planned at JLab. The new experiment will perform precision measurements
of target Single Spin Asymmetries (SSA) from semi-inclusive electro-production
of charged pions from a 40-cm long transversely polarized He target in
Deep-Inelastic-Scattering kinematics using 11 and 8.8 GeV electron beams. This
new coincidence experiment in Hall A will employ a newly proposed solenoid
spectrometer (SoLID). The large acceptance spectrometer and the high polarized
luminosity will provide precise 4-D (, , and ) data on the
Collins, Sivers, and pretzelocity asymmetries for the neutron through the
azimuthal angular dependence. The full 2 azimuthal angular coverage in the
lab is essential in controlling the systematic uncertainties. The results from
this experiment, when combined with the proton Collins asymmetry measurement
and the Collins fragmentation function determined from the ee collision
data, will allow for a quark flavor separation in order to achieve a
determination of the tensor charge of the d quark to a 10% accuracy. The
extracted Sivers and pretzelocity asymmetries will provide important
information to understand the correlations between the quark orbital angular
momentum and the nucleon spin and between the quark spin and nucleon spin.Comment: 23 pages, 13 figures, minor corrections, matches published versio
High-Performance Bioinstrumentation for Real-Time Neuroelectrochemical Traumatic Brain Injury Monitoring
Traumatic brain injury (TBI) has been identified as an important cause of death and severe disability in all age groups and particularly in children and young adults. Central to TBIs devastation is a delayed secondary injury that occurs in 30–40% of TBI patients each year, while they are in the hospital Intensive Care Unit (ICU). Secondary injuries reduce survival rate after TBI and usually occur within 7 days post-injury. State-of-art monitoring of secondary brain injuries benefits from the acquisition of high-quality and time-aligned electrical data i.e., ElectroCorticoGraphy (ECoG) recorded by means of strip electrodes placed on the brains surface, and neurochemical data obtained via rapid sampling microdialysis and microfluidics-based biosensors measuring brain tissue levels of glucose, lactate and potassium. This article progresses the field of multi-modal monitoring of the injured human brain by presenting the design and realization of a new, compact, medical-grade amperometry, potentiometry and ECoG recording bioinstrumentation. Our combined TBI instrument enables the high-precision, real-time neuroelectrochemical monitoring of TBI patients, who have undergone craniotomy neurosurgery and are treated sedated in the ICU. Electrical and neurochemical test measurements are presented, confirming the high-performance of the reported TBI bioinstrumentation
A network approach for managing and processing big cancer data in clouds
Translational cancer research requires integrative analysis of multiple levels of big cancer data to identify and treat cancer. In order to address the issues that data is decentralised, growing and continually being updated, and the content living or archiving on different information sources partially overlaps creating redundancies as well as contradictions and inconsistencies, we develop a data network model and technology for constructing and managing big cancer data. To support our data network approach for data process and analysis, we employ a semantic content network approach and adopt the CELAR cloud platform. The prototype implementation shows that the CELAR cloud can satisfy the on-demanding needs of various data resources for management and process of big cancer data
Mechanisms of oral tolerance revisited
Oral tolerance induction is thought to depend on special antigen presenting cells in the gut. A new report in the previous issue of Arthritis Research & Therapy supports this idea by demonstrating that indoleamine 2,3-dioxygenase-expressing dendritic cells in Peyer's patches from orally tolerized mice suppress T-cell responses via the generation of CD4+CD25+ regulatory T cells. This finding provides novel input into the mechanisms of oral tolerance that could further facilitate its use for the treatment of autoimmunity and chronic inflammatory reactions
HIJING 1.0: A Monte Carlo Program for Parton and Particle Production in High Energy Hadronic and Nuclear Collisions
Based on QCD-inspired models for multiple jets production, we developed a
Monte Carlo program to study jet and the associated particle production in high
energy , and collisions. The physics behind the program which
includes multiple minijet production, soft excitation, nuclear shadowing of
parton distribution functions and jet interaction in dense matter is briefly
discussed. A detailed description of the program and instructions on how to use
it are given.Comment: 38 pages in LaTex, published in Comp. Phys. Comm. 83, 307 (1994)
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