Search query: transport

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abstract: Unrestricted Travel in Solar Cells In the past 2 years, organolead halide perovskites have emerged as a promising class of light harvesting media in experimental solar cells, but the physical basis for their efficiency has been unclear (see the Perspective by Hodes) Two studies now show, using a variety of time resolved absorption and emission spectroscopic techniques, that these materials manifest relatively long diffusion paths for charge carriers energized by light absorption. Xing et al. (p. 344) independently assessed (negative) electron and (positive) hole diffusion lengths and found them well matched to one another to the ~100 nanometer optical absorption depth. Stranks et al. (p. 341) uncovered a 10 fold greater diffusion length in a chloride doped material, which correlates with the material's particularly efficient overall performance. Both studies highlight effective carrier diffusion as a fruitful parameter for further optimization. Spectroscopy pinpoints facile carrier diffusion as a key factor in the efficiency of perovskite solar cells. [Also see Perspective by Hodes] Low temperature solution processed photovoltaics suffer from low efficiencies because of poor exciton or electron hole diffusion lengths (typically about 10 nanometers) Recent reports of highly efficient CH3NH3PbI3 based solar cells in a broad range of configurations raise a compelling case for understanding the fundamental photophysical mechanisms in these materials. By applying femtosecond transient optical spectroscopy to bilayers that interface this perovskite with either selective electron or selective hole extraction materials, we have uncovered concrete evidence of balanced long range electron hole diffusion lengths of at least 100 nanometers in solution processed CH3NH3PbI3. The high photoconversion efficiencies of these systems stem from the comparable optical absorption length and charge carrier diffusion lengths, transcending the traditional constraints of solution processed semiconductors.
author_names: Guichuan Xing

Nripan Mathews

Shuangyong Sun

Swee Sien Lim

Yeng Ming Lam

Michael Gratzel

Subodh Gautam Mhaisalkar

Tze Chien Sum
title: Long Range Balanced Electron and Hole Transport Lengths in Organic Inorganic CH3NH3PbI3
venue: Science
year: 2013

abstract: Optimal transport (OT) theory can be informally described using the words of the French mathematician Gaspard Monge (1746 1818) A worker with a shovel in hand has to move a large pile of sand lying on a construction site. The goal of the worker is to erect with all that sand a target pile with a prescribed shape (for example, that of a giant sand castle) Naturally, the worker wishes to minimize her total effort, quantified for instance as the total distance or time spent carrying shovelfuls of sand. Mathematicians interested in OT cast that problem as that of comparing two probability distributions, two different piles of sand of the same volume. They consider all of the many possible ways to morph, transport or reshape the first pile into the second, and associate a "global" cost to every such transport, using the "local" consideration of how much it costs to move a grain of sand from one place to another. Recent years have witnessed the spread of OT in several fields, thanks to the emergence of approximate solvers that can scale to sizes and dimensions that are relevant to data sciences. Thanks to this newfound scalability, OT is being increasingly used to unlock various problems in imaging sciences (such as color or texture processing) computer vision and graphics (for shape manipulation) or machine learning (for regression, classification and density fitting) This short book reviews OT with a bias toward numerical methods and their applications in data sciences, and sheds lights on the theoretical properties of OT that make it particularly useful for some of these applications.
author_names: Gabriel Peyre

Marco Cuturi
title: Computational Optimal Transport
venue: Found. Trends Mach. Learn.
year: 2019

abstract: Signaling through the Ror2 receptor tyrosine kinase promotes invadopodia formation for tumor invasion. Here, we identify intraflagellar transport 20 (IFT20) as a new target of this signaling in tumors that lack primary cilia, and find that IFT20 mediates the ability of Ror2 signaling to induce the invasiveness of these tumors. We also find that IFT20 regulates the nucleation of Golgi derived microtubules by affecting the GM130 AKAP450 complex, which promotes Golgi ribbon formation in achieving polarized secretion for cell migration and invasion. Furthermore, IFT20 promotes the efficiency of transport through the Golgi complex. These findings shed new insights into how Ror2 signaling promotes tumor invasiveness, and also advance the understanding of how Golgi structure and transport can be regulated.
author_names: Michiru Nishita

Seung-Yeol Park

Tadashi Nishio

Koki Kamizaki

Zhichao Wang

Kota Tamada

Toru Takumi

Ryuju Hashimoto

Hiroki Otani

Gregory J Pazour

Victor W Hsu

Yasuhiro Minami
title: Ror2 signaling regulates Golgi structure and transport through IFT20 for tumor invasiveness
venue: Scientific Reports
year: 2016

abstract: This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery. This document updates RFCs 4492, 5705, and 6066 and it obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations.
author_names: Eric Rescorla
title: The Transport Layer Security (TLS) Protocol Version 1.3
venue: RFC
year: 2018

abstract: AbstractThe Hybrid Single Particle Lagrangian Integrated Trajectory model (HYSPLIT) developed by NOAA's Air Resources Laboratory, is one of the most widely used models for atmospheric trajectory and dispersion calculations. We present the model's historical evolution over the last 30 years from simple hand drawn back trajectories to very sophisticated computations of transport, mixing, chemical transformation, and deposition of pollutants and hazardous materials. We highlight recent applications of the HYSPLIT modeling system, including the simulation of atmospheric tracer release experiments, radionuclides, smoke originated from wild fires, volcanic ash, mercury, and wind blown dust.
author_names: Ariel F Stein

Roland R Draxler

Glenn Rolph

Barbara Stunder

Mark D Cohen

Fong Ngan
title: NOAA's HYSPLIT Atmospheric Transport and Dispersion Modeling System
year: 2015

abstract: This memorandum describes RTP, the real time transport protocol. RTP provides end to end network transport functions suitable for applications transmitting real time data, such as audio, video or simulation data, over multicast or unicast network services. RTP does not address resource reservation and does not guarantee quality of service for real time services. The data transport is augmented by a control protocol (RTCP) to allow monitoring of the data delivery in a manner scalable to large multicast networks, and to provide minimal control and identification functionality. RTP and RTCP are designed to be independent of the underlying transport and network layers. The protocol supports the use of RTP level translators and mixers.
author_names: Henning Schulzrinne

Stephen L Casner

Ron Frederick

Van Jacobson
title: RTP: A Transport Protocol for Real Time Applications
venue: RFC
year: 1996

abstract: PHREEQC version 2 is a computer program written in the C programming language that is designed to perform a wide variety of low temperature aqueous geochemical calculations. PHREEQC is based on an ion association aqueous model and has capabilities for (1) speciation and saturation index calculations; (2) batch reaction and onedimensional (1D) transport calculations involving reversible reactions, which include aqueous, mineral, gas, solidsolution, surface complexation, and ion exchange equilibria, and irreversible reactions, which include specified mole transfers of reactants, kinetically controlled reactions, mixing of solutions, and temperature changes; and (3) inverse modeling, which finds sets of mineral and gas mole transfers that account for differences in composition between waters, within specified compositional uncertainty limits. New features in PHREEQC version 2 relative to version 1 include capabilities to simulate dispersion (or diffusion) and stagnant zones in 1D transport calculations, to model kinetic reactions with user defined rate expressions, to model the formation or dissolution of ideal, multicomponent or nonideal, binary solid solutions, to model fixed volume gas phases in addition to fixed pressure gas phases, to allow the number of surface or exchange sites to vary with the dissolution or precipitation of minerals or kinetic reactants, to include isotope mole balances in inverse modeling calculations, to automatically use multiple sets of convergence parameters, to print user defined quantities to the primary output file and (or) to a file suitable for importation into a spreadsheet, and to define solution compositions in a format more compatible with spreadsheet programs. This report presents the equations that are the basis for chemical equilibrium, kinetic, transport, and inverse modeling calculations in PHREEQC; describes the input for the program; and presents examples that demonstrate most of the program's capabilities.
author_names: David L Parkhurst

C A J Appelo
title: User's guide to PHREEQC (Version 2) a computer program for speciation, batch reaction, one dimensional transport, and inverse geochemical calculations
year: 1999

abstract: Couplings and changes of variables. Three examples of coupling techniques. The founding fathers of optimal transport. Qualitative description of optimal transport. Basic properties. Cyclical monotonicity and Kantorovich duality. The Wasserstein distances. Displacement interpolation. The Monge Mather shortening principle. Solution of the Monge problem I: global approach. Solution of the Monge problem II: Local approach. The Jacobian equation. Smoothness. Qualitative picture. Optimal transport and Riemannian geometry. Ricci curvature. Otto calculus. Displacement convexity I. Displacement convexity II. Volume control. Density control and local regularity. Infinitesimal displacement convexity. Isoperimetric type inequalities. Concentration inequalities. Gradient flows I. Gradient flows II: Qualitative properties. Gradient flows III: Functional inequalities. Synthetic treatment of Ricci curvature. Analytic and synthetic points of view. Convergence of metric measure spaces. Stability of optimal transport. Weak Ricci curvature bounds I: Definition and Stability. Weak Ricci curvature bounds II: Geometric and analytic properties.
author_names: Cedric Villani
title: Optimal Transport: Old and New
year: 2008

abstract: Measurements of the quantum yields of chlorophyll fluorescence and CO2 assimilation for a number of plant species exposed to changing light intensity and atmospheric CO2 concentrations and during induction of photosynthesis are used to examine the relationship between fluorescence quenching parameters and the quantum yield of non cyclic electron transport. Over a wide range of physiological conditions the quantum yield of non cyclic electron transport was found to be directly proportional to the product of the photochemical fluorescence quenching (qQ) and the efficiency of excitation capture by open Photosystem II (PS II) reaction centres (Fv/Fm) A simple fluorescence parameter, DphF/phFm, which is defined by the difference in fluorescence yield at maximal phFm, and steady state phFs, divided by phFm, can be used routinely to estimate changes in the quantum yield of non cyclic electron transport. It is demonstrated that both the concentration of open PS II reaction centres and the efficiency of excitation capture by these centres will determine the quantum yield of non cyclic electron transport in vivo and that deactivation of excitation within PS II complexes by non photochemical processes must influence the quantum yield of non cyclic electron transport.
author_names: Bernard Genty

J-M Briantais

Neil R Baker
title: The relationship between the quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence
year: 1989

abstract: This manual is a practical guide for the use of our general purpose Monte Carlo code MCNP. The first chapter is a primer for the novice user. The second chapter describes the mathematics, data, physics, and Monte Carlo simulation found in MCNP. This discussion is not meant to be exhaustive details of the particular techniques and of the Monte Carlo method itself will have to be found elsewhere. The third chapter shows the user how to prepare input for the code. The fourth chapter contains several examples, and the fifth chapter explains the output. The appendices show how to use MCNP on various computer systems and also give details about some of the code internals.
author_names: Judith F Briesmeister
title: MCNP A General Monte Carlo N Particle Transport Code
year: 1993