9,304 research outputs found
Digital Alchemy for Materials Design: Colloids and Beyond
Starting with the early alchemists, a holy grail of science has been to make
desired materials by modifying the attributes of basic building blocks.
Building blocks that show promise for assembling new complex materials can be
synthesized at the nanoscale with attributes that would astonish the ancient
alchemists in their versatility. However, this versatility means that making
direct connection between building block attributes and bulk behavior is both
necessary for rationally engineering materials, and difficult because building
block attributes can be altered in many ways. Here we show how to exploit the
malleability of the valence of colloidal nanoparticle "elements" to directly
and quantitatively link building block attributes to bulk behavior through a
statistical thermodynamic framework we term "digital alchemy". We use this
framework to optimize building blocks for a given target structure, and to
determine which building block attributes are most important to control for
self assembly, through a set of novel thermodynamic response functions, moduli
and susceptibilities. We thereby establish direct links between the attributes
of colloidal building blocks and the bulk structures they form. Moreover, our
results give concrete solutions to the more general conceptual challenge of
optimizing emergent behaviors in nature, and can be applied to other types of
matter. As examples, we apply digital alchemy to systems of truncated
tetrahedra, rhombic dodecahedra, and isotropically interacting spheres that
self assemble diamond, FCC, and icosahedral quasicrystal structures,
respectively.Comment: 17 REVTeX pages, title fixed to match journal versio
Sizing nanomaterials in bio-fluids by cFRAP enables protein aggregation measurements and diagnosis of bio-barrier permeability
Sizing nanomaterials in complex biological fluids, such as blood, remains a great challenge in spite of its importance for a wide range of biomedical applications. In drug delivery, for instance, it is essential that aggregation of protein-based drugs is avoided as it may alter their efficacy or elicit immune responses. Similarly it is of interest to determine which size of molecules can pass through biological barriers in vivo to diagnose pathologies, such as sepsis. Here, we report on continuous fluorescence recovery after photobleaching (cFRAP) as a analytical method enabling size distribution measurements of nanomaterials (1-100 nm) in undiluted biological fluids. We demonstrate that cFRAP allows to measure protein aggregation in human serum and to determine the permeability of intestinal and vascular barriers in vivo. cFRAP is a new analytical technique that paves the way towards exciting new applications that benefit from nanomaterial sizing in bio-fluids
Modeling, Analysis, and Optimization Issues for Large Space Structures
Topics concerning the modeling, analysis, and optimization of large space structures are discussed including structure-control interaction, structural and structural dynamics modeling, thermal analysis, testing, and design
Progettazione multidisciplinare ottimizzata nelle microturbine a gas
Optimized multidisciplinary design in micro-gasturbine
Aeronautical Engineering. A continuing bibliography with indexes, supplement 156
This bibliography lists 288 reports, articles and other documents introduced into the NASA scientific and technical information system in December 1982
Statistical Physics of Design
Modern life increasingly relies on complex products that perform a variety of functions. The key difficulty of creating such products lies not in the manufacturing process, but in the design process. However, design problems are typically driven by multiple contradictory objectives and different stakeholders, have no obvious stopping criteria, and frequently prevent construction of prototypes or experiments. Such ill-defined, or "wicked" problems cannot be "solved" in the traditional sense with optimization methods. Instead, modern design techniques are focused on generating knowledge about the alternative solutions in the design space.
In order to facilitate such knowledge generation, in this dissertation I develop the "Systems Physics" framework that treats the emergent structures within the design space as physical objects that interact via quantifiable forces. Mathematically, Systems Physics is based on maximal entropy statistical mechanics, which allows both drawing conceptual analogies between design problems and collective phenomena and performing numerical calculations to gain quantitative understanding. Systems Physics operates via a Model-Compute-Learn loop, with each step refining our thinking of design problems.
I demonstrate the capabilities of Systems Physics in two very distinct case studies: Naval Engineering and self-assembly. For the Naval Engineering case, I focus on an established problem of arranging shipboard systems within the available hull space. I demonstrate the essential trade-off between minimizing the routing cost and maximizing the design flexibility, which can lead to abrupt phase transitions. I show how the design space can break into several locally optimal architecture classes that have very different robustness to external couplings. I illustrate how the topology of the shipboard functional network enters a tight interplay with the spatial constraints on placement. For the self-assembly problem, I show that the topology of self-assembled structures can be reliably encoded in the properties of the building blocks so that the structure and the blocks can be jointly designed.
The work presented here provides both conceptual and quantitative advancements. In order to properly port the language and the formalism of statistical mechanics to the design domain, I critically re-examine such foundational ideas as system-bath coupling, coarse graining, particle distinguishability, and direct and emergent interactions. I show that the design space can be packed into a special information structure, a tensor network, which allows seamless transition from graphical visualization to sophisticated numerical calculations.
This dissertation provides the first quantitative treatment of the design problem that is not reduced to the narrow goals of mathematical optimization. Using statistical mechanics perspective allows me to move beyond the dichotomy of "forward" and "inverse" design and frame design as a knowledge generation process instead. Such framing opens the way to further studies of the design space structures and the time- and path-dependent phenomena in design. The present work also benefits from, and contributes to the philosophical interpretations of statistical mechanics developed by the soft matter community in the past 20 years. The discussion goes far beyond physics and engages with literature from materials science, naval engineering, optimization problems, design theory, network theory, and economic complexity.PHDPhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163133/1/aklishin_1.pd
Publications of the Jet Propulsion Laboratory, July 1964 through June 1965
JPL publications bibliography with abstracts - reports on DSIF, Mariner program, Ranger project, Surveyor project, and other space programs, and space science
Aeronautical engineering: A continuing bibliography, supplement 122
This bibliography lists 303 reports, articles, and other documents introduced into the NASA scientific and technical information system in April 1980
Advances in Bearing Lubrication and Thermal Sciences
This reprint focuses on the hot issue of bearing lubrication and thermal analysis, and brings together many cutting-edge studies, such as bearing multi-body dynamics, bearing tribology, new lubrication and heat dissipation structures, bearing self-lubricating materials, thermal analysis of bearing assembly process, bearing service state prediction, etc. The purpose of this reprint is to explore recent developments in bearing thermal mechanisms and lubrication technology, as well as the impact of bearing operating parameters on their lubrication performance and thermal behavior
Artificial cognitive architecture with self-learning and self-optimization capabilities. Case studies in micromachining processes
Tesis doctoral inédita leÃda en la Universidad Autónoma de Madrid, Escuela Politécnica Superior, Departamento de IngenierÃa Informática. Fecha de lectura : 22-09-201
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