23,945 research outputs found
Sensitivity of a highâelevation rocky mountain watershed to altered climate and CO2
We explored the hydrologic and ecological responses of a headwater mountain catchment, Loch Vale watershed, to climate change and doubling of atmospheric CO2 scenarios using the Regional HydroâEcological Simulation System (RHESSys). A slight (2°C) cooling, comparable to conditions observed over the past 40 years, led to greater snowpack and slightly less runoff, evaporation, transpiration, and plant productivity. An increase of 2°C yielded the opposite response, but model output for an increase of 4°C showed dramatic changes in timing of hydrologic responses. The snowpack was reduced by 50%, and runoff and soil water increased and occurred 4â5 weeks earlier with 4°C warming. Alpine tundra photosynthetic rates responded more to warmer and wetter conditions than subalpine forest, but subalpine forest showed a greater response to doubling of atmospheric CO2 than tundra. Even though water use efficiency increased with the double CO2 scenario, this had little effect on basinâwide runoff because the catchment is largely unvegetated. Changes in winter and spring climate conditions were more important to hydrologic and vegetation dynamics than changes that occurred during summer
Aerospace Medicine and Biology: A continuing bibliography with indexes (supplement 291)
This bibliography lists 131 reports, articles and other documents introduced into the NASA scientific and technical information system in November 1986
Anisotropically Shaped Magnetic/Plasmonic Nanocomposites for Information Encryption and Magnetic-Field-Direction Sensing.
Instantaneous control over the orientation of anisotropically shaped plasmonic nanostructures allows for selective excitation of plasmon modes and enables dynamic tuning of the plasmonic properties. Herein we report the synthesis of rod-shaped magnetic/plasmonic core-shell nanocomposite particles and demonstrate the active tuning of their optical property by manipulating their orientation using an external magnetic field. We further design and construct an IR-photoelectric coupling system, which generates an output voltage depending on the extinction property of the measured nanocomposite sample. We employ the device to demonstrate that the nanocomposite particles can serve as units for information encryption when immobilized in a polymer film and additionally when dispersed in solution can be employed as a new type of magnetic-field-direction sensor
Case Studies:
Adaptive building envelopes can provide improvements in building energy efficiency and economics, through their capability to change their behaviour in real time according to indooroutdoor parameters. This may be by means of materials, components or systems. As such, adaptive façades can make a significant and viable contribution to meeting the EUŽs 2020 targets. Several different adaptive façade concepts have already been developed, and an increase in emerging, innovative solutions is expected in the near future. In this context the EU initiative COST Action TU 1403 aims to harmonize, share and disseminate technological knowledge on adaptive facades at a European level.
According to the definition given by this COST Action, an adaptive façade is a building envelope consisting of multifunctional and highly adaptive systems that is able to change its functions, features, or behaviour over time in response to transient performance requirements and boundary conditions, with the aim of improving the overall building performance.
In order to explore the available and emerging technologies focusing on adaptive façades, Working Group 1 of the COST Action undertook research to form a database of adaptive façade case studies and projects structured in accordance with a simple classification â materials, components and systems. In addition to this, details of the purpose of the systems/components/materials with adaptive features and the working principle of each technology were also collected together with data regarding design practice, technology readiness, and economical aspects, among others.
The information was collected with the help of a specific online survey (structured in the following main sections: detailed description - metrics- characterization- economic aspects â references). The database includes 165 cases of adaptive façade systems, components, and materials that allowed a variety of analyses to be carried out. According to the classification adopted within WG1 (materials, components, systems), each of the classification terms are introduced together with examples from the case study database in the following sections. This volume ends with a section dedicated to future developments, where different issues are addressed such as embedded functionality and efficiency amd biomimetic inspirations. The importance of adaptive façades through their flexibility, and intelligent design within the context of smart cities is also discussed.
The work within Working Group 1 - Adaptive technologies and products was developed within four distinct sub-groups (SG) in order to provide outputs according to the objectives of this WG and the COST Action: SG1 â Database, SG2 â Educational Pack, SG3 â Publications and Reports and SG4 â Short Term Scientific Missions (STSM).
This work was possible due to the strong commitment and work of all WG1 members: Laura Aelenei, Aleksandra KrstiÄ-FurundĆŸiÄ, Daniel Aelenei, Marcin Brzezicki, Tillmann Klein, Jose Miguel Rico-MartĂnez, Theoni Karlessi, Christophe Menezo, Susanne Gosztonyi, Nikolaus Nestle, Jerry Eriksson, Mark Alston, Rosa Romano, Maria da GlĂłria Gomes, Enrico Sergio Mazzucchelli, Sandra Persiani, Claudio Aresta, Nitisha Vedula, Miren Juaristi
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High-Performance Integrated Window and Façade Solutions for California
The researchers developed a new generation of high-performance façade systems and supporting design and management tools to support industry in meeting Californiaâs greenhouse gas reduction targets, reduce energy consumption, and enable an adaptable response to minimize real-time demands on the electricity grid. The project resulted in five outcomes: (1) The research team developed an R-5, 1-inch thick, triplepane, insulating glass unit with a novel low-conductance aluminum frame. This technology can help significantly reduce residential cooling and heating loads, particularly during the evening. (2) The team developed a prototype of a windowintegrated local ventilation and energy recovery device that provides clean, dry fresh air through the façade with minimal energy requirements. (3) A daylight-redirecting louver system was prototyped to redirect sunlight 15â40 feet from the window. Simulations estimated that lighting energy use could be reduced by 35â54 percent without glare. (4) A control system incorporating physics-based equations and a mathematical solver was prototyped and field tested to demonstrate feasibility. Simulations estimated that total electricity costs could be reduced by 9-28 percent on sunny summer days through adaptive control of operable shading and daylighting components and the thermostat compared to state-of-the-art automatic façade controls in commercial building perimeter zones. (5) Supporting models and tools needed by industry for technology R&D and market transformation activities were validated. Attaining Californiaâs clean energy goals require making a fundamental shift from todayâs ad-hoc assemblages of static components to turnkey, intelligent, responsive, integrated building façade systems. These systems offered significant reductions in energy use, peak demand, and operating cost in California
Adaptive locomotion of artificial microswimmers
Bacteria can exploit mechanics to display remarkable plasticity in response
to locally changing physical and chemical conditions. Compliant structures play
a striking role in their taxis behavior, specifically for navigation inside
complex and structured environments. Bioinspired mechanisms with rationally
designed architectures capable of large, nonlinear deformation present
opportunities for introducing autonomy into engineered small-scale devices.
This work analyzes the effect of hydrodynamic forces and rheology of local
surroundings on swimming at low Reynolds number, identifies the challenges and
benefits of utilizing elastohydrodynamic coupling in locomotion, and further
develops a suite of machinery for building untethered microrobots with
self-regulated mobility. We demonstrate that coupling the structural and
magnetic properties of artificial microswimmers with the dynamic properties of
the fluid leads to adaptive locomotion in the absence of on-board sensors
Quantum-Enhanced Diamond Molecular Tension Microscopy for Quantifying Cellular Forces
The constant interplay and information exchange between cells and their
micro-environment are essential to their survival and ability to execute
biological functions. To date, a few leading technologies such as traction
force microscopy, have been broadly used in measuring cellular forces. However,
the considerable limitations, regarding the sensitivity and ambiguities in data
interpretation, are hindering our thorough understanding of mechanobiology.
Herein, we propose an innovative approach, namely quantum-enhanced diamond
molecular tension microscopy (QDMTM), to precisely quantify the integrin-based
cell adhesive forces. Specifically, we construct a force sensing platform by
conjugating the magnetic nanotags labeled, force-responsive polymer to the
surface of diamond membrane containing nitrogen vacancy (NV) centers. Thus, the
coupled mechanical information can be quantified through optical readout of
spin relaxation of NV centers modulated by those magnetic nanotags. To validate
QDMTM, we have carefully performed corresponding measurements both in control
and real cell samples. Particularly, we have obtained the quantitative cellular
adhesion force mapping by correlating the measurement with established
theoretical model. We anticipate that our method can be routinely used in
studying important issues like cell-cell or cell-material interactions and
mechanotransduction.Comment: 51 pages, 20 figure
Numerical study of surface tension driven convection in thermal magnetic fluids
Microgravity conditions pose unique challenges for fluid handling and heat transfer applications. By controlling (curtailing or augmenting) the buoyant and thermocapillary convection, the latter being the dominant convective flow in a microgravity environment, significant advantages can be achieved in space based processing. The control of this surface tension gradient driven flow is sought using a magnetic field, and the effects of these are studied computationally. A two-fluid layer system, with the lower fluid being a non-conducting ferrofluid, is considered under the influence of a horizontal temperature gradient. To capture the deformable interface, a numerical method to solve the Navier???Stokes equations, heat equations, and Maxwell???s equations was developed using a hybrid level set/ volume-of-fluid technique. The convective velocities and heat fluxes were studied under various regimes of the thermal Marangoni number Ma, the external field represented by the magnetic Bond number Bom, and various gravity levels, Fr. Regimes where the convection were either curtailed or augmented were identified. It was found that the surface force due to the step change in the magnetic permeability at the interface could be suitably utilized to control the instability at the interface.published or submitted for publicationis peer reviewe
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