108,637 research outputs found
Electricity from photovoltaic solar cells: Flat-Plate Solar Array Project final report. Volume VII: Module encapsulation
The Flat-Plate Solar Array (FSA) Project, funded by the U.S. Government and managed by the Jet Propulsion Laboratory, was formed in 1975 to develop the module/array technology needed to attain widespread terrestrial use of photovoltaics by 1985. To accomplish this, the FSA Project established and managed an Industry, University, and Federal Government Team to perform the needed research and development.
The objective of the Encapsulation Task was to develop, demonstrate, and qualify photovoltaic (PV) module encapsulation systems that would provide 20-year (later increased to 30-year) life expectancies in terrestrial environments, and which would be compatible with the cost and performance goals of the FSA Project. The scope of the Encapsulation Task included the identification, development, and evaluation of material systems and configurations required to support and protect the optically and electrically active solar cell circuit components in the PV module operating environment. Encapsulation material technologies summarized in this report include the development of low-cost ultraviolet protection techniques, stable low-cost pottants, soiling resistant coatings, electrical isolation criteria, processes for optimum interface bonding, and analytical and experimental tools for evaluating the long-term durability and structural adequacy of encapsulated modules. Field testing, accelerated stress testing, and design studies have demonstrated that encapsulation materials, processes, and configurations are available that will meet the FSA cost and performance goals. Thirty-year module life expectancies are anticipated based on accelerated stress testing results and on extrapolation of real-time field exposures in excess of 9 years
Violation of the fluctuation-dissipation theorem in glassy systems: basic notions and the numerical evidence
This review reports on the research done during the past years on violations
of the fluctuation-dissipation theorem (FDT) in glassy systems. It is focused
on the existence of a quasi-fluctuation-dissipation theorem (QFDT) in glassy
systems and the currently supporting knowledge gained from numerical simulation
studies. It covers a broad range of non-stationary aging and stationary driven
systems such as structural-glasses, spin-glasses, coarsening systems,
ferromagnetic models at criticality, trap models, models with entropy barriers,
kinetically constrained models, sheared systems and granular media. The review
is divided into four main parts: 1) An introductory section explaining basic
notions related to the existence of the FDT in equilibrium and its possible
extension to the glassy regime (QFDT), 2) A description of the basic analytical
tools and results derived in the framework of some exactly solvable models, 3)
A detailed report of the current evidence in favour of the QFDT and 4) A brief
digression on the experimental evidence in its favour. This review is intended
for inexpert readers who want to learn about the basic notions and concepts
related to the existence of the QFDT as well as for the more expert readers who
may be interested in more specific results.Comment: 120 pages, 37 figures. Topical review paper . Several typos and
misprints corrected, new references included and others updated. to be
published in J. Phys. A (Math. Gen.
Optical absorption and electrical conductivity of electron acceptor doped poly-3-octylthiophene films
Optical absorption and electrical conductivity measurements of solution-doped poly-3-octylthiophene (P3OT) films were studied. Chloroform solutions of P3OT were doped with the organic electron-acceptors, 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ); and with the inorganic electron acceptor, ferric chloride (FeCl{dollar}\sb3{dollar}). Charge transfer was observed in P3OT solutions doped with FeCl{dollar}\sb3{dollar} and DDQ. TCNQ-doped solutions showed no optical evidence of charge transfer. Thin films of the doped P3OT were examined at various doping levels. Spectroscopic and electrical conductivity measurements of P3OT films, doped with DDQ, TCNQ, and FeCl{dollar}\sb3{dollar}, at different doping levels, are presented. Optical absorption measurements provided information on the degree of charge transfer occurring for the various dopants. Electrical conductivity measurements showed that the conductivity of P3OT increased with the various dopants in the order of TCNQ {dollar}\u3c{dollar} DDQ {dollar}\u3c{dollar} FeCl{dollar}\sb3{dollar}, for the same dopant concentration level. Results are discussed in relation to the electrochemical properties of the prepared films and the structural properties of P3OT
Data-driven modelling of biological multi-scale processes
Biological processes involve a variety of spatial and temporal scales. A
holistic understanding of many biological processes therefore requires
multi-scale models which capture the relevant properties on all these scales.
In this manuscript we review mathematical modelling approaches used to describe
the individual spatial scales and how they are integrated into holistic models.
We discuss the relation between spatial and temporal scales and the implication
of that on multi-scale modelling. Based upon this overview over
state-of-the-art modelling approaches, we formulate key challenges in
mathematical and computational modelling of biological multi-scale and
multi-physics processes. In particular, we considered the availability of
analysis tools for multi-scale models and model-based multi-scale data
integration. We provide a compact review of methods for model-based data
integration and model-based hypothesis testing. Furthermore, novel approaches
and recent trends are discussed, including computation time reduction using
reduced order and surrogate models, which contribute to the solution of
inference problems. We conclude the manuscript by providing a few ideas for the
development of tailored multi-scale inference methods.Comment: This manuscript will appear in the Journal of Coupled Systems and
Multiscale Dynamics (American Scientific Publishers
On the Properties of the Reaction Counts Chemical Master Equation
The reaction counts chemical master equation (CME) is a high-dimensional variant of the classical population counts CME. In the reaction counts CME setting, we count the reactions which have fired over time rather than monitoring the population state over time. Since a reaction either fires or not, the reaction counts CME transitions are only forward stepping. Typically there are more reactions in a system than species, this results in the reaction counts CME being higher in dimension, but simpler in dynamics. In this work, we revisit the reaction counts CME framework and its key theoretical results. Then we will extend the theory by exploiting the reactions counts’ forward stepping feature, by decomposing the state space into independent continuous-time Markov chains (CTMC). We extend the reaction counts CME theory to derive analytical forms and estimates for the CTMC decomposition of the CME. This new theory gives new insights into solving hitting times-, rare events-, and a priori domain construction problems
Reciprocal Relations Between Kinetic Curves
We study coupled irreversible processes. For linear or linearized kinetics
with microreversibility, , the kinetic operator is symmetric in
the entropic inner product. This form of Onsager's reciprocal relations implies
that the shift in time, , is also a symmetric operator. This
generates the reciprocity relations between the kinetic curves. For example,
for the Master equation, if we start the process from the th pure state and
measure the probability of the th state (), and,
similarly, measure for the process, which starts at the th pure
state, then the ratio of these two probabilities is constant in
time and coincides with the ratio of the equilibrium probabilities. We study
similar and more general reciprocal relations between the kinetic curves. The
experimental evidence provided as an example is from the reversible water gas
shift reaction over iron oxide catalyst. The experimental data are obtained
using Temporal Analysis of Products (TAP) pulse-response studies. These offer
excellent confirmation within the experimental error.Comment: 6 pages, 1 figure, the final versio
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