6,773 research outputs found

    Save Money or Feel Cozy?: A Field Experiment Evaluation of a Smart Thermostat that Learns Heating Preferences

    Get PDF
    We present the design of a fully autonomous smart thermostat that supports end-users in managing their heating preferences in a realtime pricing regime. The thermostat uses a machine learning algorithm to learn how a user wants to trade off comfort versus cost. We evaluate the thermostat in a field experiment in the UK involving 30 users over a period of 30 days. We make two main contributions. First, we study whether our smart thermostat enables end-users to handle real-time prices, and in particular, whether machine learning can help them. We find that the users trust the system and that they can successfully express their preferences; overall, the smart thermostat enables the users to manage their heating given real-time prices. Moreover, our machine learning-based thermostats outperform a baseline without machine learning in terms of usability. Second, we present a quantitative analysis of the users’ economic behavior, including their reaction to price changes, their price sensitivity, and their comfort-cost trade-offs. We find a wide variety regarding the users’ willingness to make trade-offs. But in aggregate, the users’ settings enabled a large amount of demand response, reducing the average energy consumption during peak hours by 38%

    A weldability study of AL-CU-LI 2198 alloy

    Get PDF
    Al-Cu-Li alloys, conceived for automotive and aeronautic applications thanks to the high mechanical resistance/density ratio, exhibit weldability issues common to all light alloys. In this paper, the weldability of Al-Cu-Li 2198 alloy was studied by comparing features of welds carried out by two processes, the traditional arc welding and the friction stir welding (FSW). Welded joints were submitted to optical and SEM metallographic examinations with EDS microanalysis measurements. Mechanical characteristics were evaluated through microhardness tests and the instrumented indentation test FIMEC (Flat-top cylinder Indenter for MEchanical Characterization)

    Critical role for prokineticin 2 in CNS autoimmunity

    Get PDF
    Objective: To investigate the potential role of prokineticin 2 (PK2), a bioactive peptide involved in multiple biological functions including immune modulation, in CNS autoimmune demyelinating disease. Methods: We investigated the expression of PK2 in mice with experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis (MS), and in patients with relapsing-remitting MS. We evaluated the biological effects of PK2 on expression of EAE and on development of T-cell response against myelin by blocking PK2 in vivo with PK2 receptor antagonists. We treated with PK2 immune cells activated against myelin antigen to explore the immune-modulating effects of this peptide in vitro. Results: Pk2 messenger RNA was upregulated in spinal cord and lymph node cells (LNCs) of mice with EAE. PK2 protein was expressed in EAE inflammatory infiltrates and was increased in sera during EAE. In patients with relapsing-remitting MS, transcripts for PK2 were significantly increased in peripheral blood mononuclear cells compared with healthy controls, and PK2 serum concentrations were significantly higher. A PK2 receptor antagonist prevented or attenuated established EAE in chronic and relapsing-remitting models, reduced CNS inflammation and demyelination, and decreased the production of interferon (IFN)-γ and interleukin (IL)-17A cytokines in LNCs while increasing IL-10. PK2 in vitro increased IFN-γ and IL-17A and reduced IL-10 in splenocytes activated against myelin antigen. Conclusion: These data suggest that PK2 is a critical immune regulator in CNS autoimmune demyelination and may represent a new target for therapy

    Heat Conduction and Microconvection in Nanofluids: Comparison between Theoretical Models and Experimental Results

    Get PDF
    A nanofluid is a suspension consisting of a uniform distribution of nanoparticles in a base fluid, generally a liquid. Nanofluid can be used as a working fluid in heat exchangers to dissipate heat in the automotive, solar, aviation, aerospace industries. There are numerous physical phenomena that affect heat conduction in nanofluids: clusters, the formation of adsorbate nanolayers, scattering of phonons at the solid–liquid interface, Brownian motion of the base fluid and thermophoresis in the nanofluids. The predominance of one physical phenomenon over another depends on various parameters, such as temperature, size and volume fraction of the nanoparticles. Therefore, it is very difficult to develop a theoretical model for estimating the effective thermal conductivity of nanofluids that considers all these phenomena and is accurate for each value of the influencing parameters. The aim of this study is to promote a way to find the conditions (temperature, volume fraction) under which certain phenomena prevail over others in order to obtain a quantitative tool for the selection of the theoretical model to be used. For this purpose, two sets (SET-I, SET-II) of experimental data were analyzed; one was obtained from the literature, and the other was obtained through experimental tests. Different theoretical models, each considering some physical phenomena and neglecting others, were used to explain the experimental results. The results of the paper show that clusters, the formation of the adsorbate nanolayer and the scattering of phonons at the solid–liquid interface are the main phenomena to be considered when ϕ = 1 ÷ 3%. Instead, at a temperature of 50 ◦C and in the volume fraction range (0.04–0.22%), microconvection prevails over other phenomen

    Deployment of solar sails by joule effect: thermal analysis and experimental results

    Get PDF
    Space vehicles may be propelled by solar sails exploiting the radiation pressure coming from the sun and applied on their surfaces. This work deals with the adoption of Nickel-Titanium Shape Memory Alloy (SMA) elements in the sail deployment mechanism activated by the Joule Effect, i.e., using the same SMA elements as a resistance within suitable designed electrical circuits. Mathematical models were analyzed for the thermal analysis by implementing algorithms for the evaluation of the temperature trend depending on the design parameters. Several solar sail prototypes were built up and tested with different number, size, and arrangement of the SMA elements, as well as the type of the selected electrical circuit. The main parameters were discussed in the tested configurations and advantages discussed as well

    Experimental Tests of Conduction/Convection Heat Transfer in Very High Porosity Foams with Lattice Structures, Immersed in Different Fluids

    Get PDF
    This experimental work presents the results of measurements of thermal conductivity lambda and convection heat transfer coefficient h on regular structure PLA and aluminium foams with low density ratio (similar to 0.15), carried out with a TCP (thermal conductivity probe), built by the authors' laboratory. Measurements were performed with two fluids, water and air: pure fluids, and samples with the PLA and aluminium foams immersed in both fluids have been tested. Four temperatures (10, 20, 30, 40 degrees C) and various temperature differences during the tests Delta T (between 0.35 and 9 degrees C) were applied. Also, tests in water mixed with 0.5% of a gel (agar agar) have been run in order to increase the water viscosity and to avoid convection starting. For these tests, at the end of the heating, the temperature of the probe reaches steady-state values, when all the thermal power supplied by the probe is transferred to the cooled cell wall; thermal conductivity was also evaluated through the guarded hot ring (GHR) method. A difference was found between the results of lambda in steady-state and transient regimes, likely due to the difference of the sample volume interested by heating during the tests. Also, the effect of the temperature difference Delta T on the behaviour of the pure fluid and foams was outlined. The mutual effect of thermal conductivity and free convection heat transfer results in being extremely important to describe the behaviour of such kinds of composites when they are used to increase or to reduce the heat transfer, as heat conductors or insulators. Very few works are present in the literature about this subject, above all, ones regarding low-density regular structures

    The costs of increasing precision for ecosystem services valuation studies

    Get PDF
    Ecosystem services valuation (ESV) is increasingly used to provide the impetus to sustainably manage and restore ecosystems. When undertaking an ESV study, the available resources, desired scope, and necessary precision must be considered before determining the most appropriate approach. A broad range of techniques exist to support valuation studies, requiring a range of financial, time, and personnel resources. We surveyed authors that completed 56 responses around valuation studies regarding their total costs (including personnel costs) and the perceived precision of their results. Results show that the perceived precision of their results is statistically significant and increases with the cost of a study (adjusted R2 = 0.29, p = 0.018) and the number of person years required to complete it (R2 = 0.31, p = 0.22). Understanding the trade-offs between the costs of the study and the precision of the results allows policymakers and practitioners to make more informed decisions about which ESV methods are most cost effective for their needs. For example, basic value transfer techniques require minimal resources to implement but lack precision in the final estimates, while integrated modelling techniques provide dynamic, spatially explicit, and more precise estimates but are significantly more expensive and time consuming to implement. However, these techniques are not mutually exclusive. A quick, inexpensive initial analysis may support and motivate more elaborate and detailed studies

    Analysis of BRCA1 and RAD51C promoter methylation in italian families at high-risk of breast and ovarian cancer

    Get PDF
    Previous studies on breast and ovarian carcinoma (BC and OC) revealed constitutional BRCA1 and RAD51C promoter hypermethylation as epigenetic alterations leading to tumor predisposition. Nevertheless, the impact of epimutations at these genes is still debated. One hundred and eight women affected by BC, OC, or both and considered at very high risk of carrying BRCA1 germline mutations were studied. All samples were negative for pathogenic variants or variants of uncertain significance at BRCA testing. Quantitative BRCA1 and RAD51C promoter methylation analyses were performed by Epityper mass spectrometry on peripheral blood samples and results were compared with those in controls. All the 108 analyzed cases showed methylation levels at the BRCA1/RAD51C promoter comparable with controls. Mean methylation levels (\ub1 stdev) at the BRCA1 promoter were 4.3% (\ub1 1.4%) and 4.4% (\ub1 1.4%) in controls and patients, respectively (p > 0.05; t-test); mean methylation levels (\ub1 stdev) at the RAD51C promoter were 4.3% (\ub1 0.9%) and 3.7% (\ub1 0.9%) in controls and patients, respectively (p > 0.05; t-test). Based on these observations; the analysis of constitutional methylation at promoters of these genes does not seem to substantially improve the definition of cancer risks in patients. These data support the idea that epimutations represent a very rare event in high-risk BC/OC populations

    The Straw Tube Trackers of the PANDA Experiment

    Full text link
    The PANDA experiment will be built at the FAIR facility at Darmstadt (Germany) to perform accurate tests of the strong interaction through bar pp and bar pA annihilation's studies. To track charged particles, two systems consisting of a set of planar, closed-packed, self-supporting straw tube layers are under construction. The PANDA straw tubes will have also unique characteristics in term of material budget and performance. They consist of very thin mylar-aluminized cathodes which are made self-supporting by means of the operation gas-mixture over-pressure. This solution allows to reduce at maximum the weight of the mechanical support frame and hence the detector material budget. The PANDA straw tube central tracker will not only reconstruct charged particle trajectories, but also will help in low momentum (< 1 GeV) particle identification via dE/dx measurements. This is a quite new approach that PANDA tracking group has first tested with detailed Monte Carlo simulations, and then with experimental tests of detector prototypes. This paper addresses the design issues of the PANDA straw tube trackers and the performance obtained in prototype tests.Comment: 7 pages,16 figure

    PosterVote:expanding the action repertoire for local political activism

    Get PDF
    Online and digital technologies support and extend the action repertoires of localized social movements. In this paper we examine the ways by which digital technologies can support ‘on-the-ground ’ activist communities in the development of social movements. After identifying some of the challenges of deploying conventional voting and consultation technologies for activism, we examine situated political action in local communities through the design and deployment of a low-cost community voting prototype, PosterVote. We deploy PosterVote in two case studies with two local community organizations identifying the features that supported or hindered grassroots democratic practices. Through interviews with these communities, we explore the design of situated voting systems to support grassroots democratic practices and participation within an ecology of social action. Author Keywords Democracy; activism; participation; e-votin
    • …
    corecore