2,602 research outputs found

    Assessing the time-sensitive impacts of energy efficiency and flexibility in the US building sector

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    The building sector consumes 75% of US electricity, offering substantial energy, cost, and CO2 emissions savings potential. New technologies enable buildings to flexibly manage electric loads across different times of day and season in support of a low-cost, low-carbon electric grid. Assessing the value of such technologies requires an understanding of building electric load variability at a higher temporal resolution than is demonstrated in previous studies of US building efficiency potential. We adapt Scout, an open-access model of US building energy use, to characterize sub-annual variations in baseline building electricity use, costs, and emissions at the national scale. We apply this baseline in time-sensitive analyses of the energy, cost, and CO2 emissions savings potential of various degrees of energy efficiency and flexibility, finding that efficiency continues to have strong value in a time-sensitive assessment framework while the value of flexibility depends on assumed electricity rates, measure magnitude and duration, and the amount of savings already captured by efficiency

    A Diversity-Oriented Synthesis Approach to Functionalized Azaheterocycles using Cyclic Alpha-Halo Eneformamides

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    Functionalized piperidines, azepanes, azamacrocycles, morpholines, and thiomorpholines are common structural motifs found in a wide range of pharmaceuticals such as carmegliptine, levofloxacin, thioridazine, claviciptic acid, and azithomycin. As a result, there is a strong desire to construct highly functionalized nitrogen-bearing ring scaffolds in order to construct a wide range of drug possibilities. There are several non-modular and step-uneconomical synthetic methods used in the construction of these aforementioned motifs such as ring closing metathesis, ring expansions, and intramolecular reductive amination. In this research, we present a step-economical, cost-effective, scalable, and diversity-oriented synthesis approach to highly functionalized N-heterocycles through the intermediacy of α-halo enamines/enamides. The synthetic utility of the method is exemplified through the construction of quaternary cyclic propargylic and homoallylic amines, polycyclic lactams, as well as chiral dihydro 1,4-oxazines and thiazines. Given the generality of the approach, we are confident that the synthesis and medicinal chemistry communities will undoubtedly embrace it, thus, endowing it with a practical advantage over existing methodologies

    Cold atom realizations of Brownian motors

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    Brownian motors are devices which "rectify" Brownian motion, i.e. they can generate a current of particles out of unbiased fluctuations. Brownian motors are important for the understanding of molecular motors, and are also promising for the realization of new nanolelectronic devices. Among the different systems that can be used to study Brownian motors, cold atoms in optical lattices are quite an unusual one: there is no thermal bath and both the potential and the fluctuations are determined by laser fields. In this article recent experimental implementations of Brownian motors using cold atoms in optical lattices are reviewed

    Recombination in polymer-fullerene bulk heterojunction solar cells

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    Recombination of photogenerated charge carriers in polymer bulk heterojunction (BHJ) solar cells reduces the short circuit current (Jsc) and the fill factor (FF). Identifying the mechanism of recombination is, therefore, fundamentally important for increasing the power conversion efficiency. Light intensity and temperature dependent current-voltage measurements on polymer BHJ cells made from a variety of different semiconducting polymers and fullerenes show that the recombination kinetics are voltage dependent and evolve from first order recombination at short circuit to bimolecular recombination at open circuit as a result of increasing the voltage-dependent charge carrier density in the cell. The "missing 0.3V" inferred from comparison of the band gaps of the bulk heterojunction materials and the measured open circuit voltage at room temperature results from the temperature dependence of the quasi-Fermi-levels in the polymer and fullerene domains - a conclusion based upon the fundamental statistics of Fermions.Comment: Accepted for publication in Physical Review B. http://prb.aps.org/accepted/B/6b07cO3aHe71bd1b149e1425e58bf2868cda2384d?ajax=1&height=500&width=50

    The extension problem for Lee and Euclidean weights

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    The extension problem is solved for the Lee and Euclidean weights over three families of rings of the form Z/NZ\Z/N\Z: N=2ℓ+1N=2^{\ell + 1}, N=3ℓ+1N=3^{\ell + 1}, or N=p=2q+1N=p=2q+1 with pp and qq prime. The extension problem is solved for the Euclidean PSK weight over Z/NZ\Z/N\Z for all NN

    Polaron Recombination in Pristine and Annealed Bulk Heterojunction Solar Cells

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    The major loss mechanism of photogenerated polarons was investigated in P3HT:PCBM solar cells by the photo-CELIV technique. For pristine and annealed devices, we find that the experimental data can be explained by a bimolecular recombination rate reduced by a factor of about ten (pristine) and 25 (annealed) as compared to Langevin theory. Aided by a macroscopic device model, we discuss the implications of the lowered loss rate on the characteristics of polymer:fullerene solar cells.Comment: 3 pages, 4 figure

    Communicating About Fascia: History, Pitfalls, and Recommendations

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    The modern reader and author need to be aware of possible ambiguities and misunderstandings stemming from different meanings of the word “fascia” because the general meaning of the term can be so vague as to imply little more than some form of connective tissue. “Fascia” encompasses both loose and dense, superficial and deep, and multiple- and single-layered connective tissues. To foster communication, we here suggest twelve specific terms to describe specified aspects of fascial tissue

    Acupuncture Point Localization Varies Among Acupuncturists

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    Background: Studies assessing the point-specific effect of acupuncture or the characteristics of acupuncture points (APs) tend to yield inconclusive results. In order to identify a possible confounding factor, we aimed to examine the variability in AP localization by means of a survey. Material and Methods: Attendees of the 14th ICMART (International Council of Medical Acupuncture and Related Techniques) congress as well as DAGfA (German Medical Society of Acupuncture) lecturers and students were asked to locate and mark the APs LI 10 and TH 5 on a research assistant's arm. Identified points were transferred into a coordinate system, and the respective bivariate distribution function was calculated. Additionally, participants filled out a questionnaire about their acupuncture education and experience, the acupuncture style and point localization techniques used most frequently, and their estimation of the size of an AP. Results: The areas of the ellipses, theoretically containing 95% of AP localizations, varied between 44.49 and 5.18 cm(2). The largest distance between 2 identified points was 8.45 cm for LI 10 and 5.3 cm for TH 5. Apart from being trained at the same school, no other factor could be identified that determined the variability in AP localization. Conclusion: Our results indicate that congruity of AP localization among experienced acupuncturists might be low. Although there are some limitations to our results, this possible bias should be taken into account when conducting acupuncture trials and interpreting results of previous acupuncture studies

    Direct optical observations of surface thermal motions at sub-shot noise levels

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    We measure spectral properties of surface thermal fluctuations of liquids, solids, complex fluids and biological matter using light scattering methods. The random thermal fluctuations are delineated from random noise at sub-shot noise levels. The principle behind this extraction, which is quite general and is not limited to surface measurements, is explained. An optical lever is used to measure the spectrum of fluctuations in the inclinations of surfaces down to ∌10−17rad2/Hz\sim 10^{-17}\rm rad^2/Hz at 1∌10ÎŒ1\sim10 \muW optical intensity, corresponding to ∌10−29m2/Hz\sim 10^{-29} \rm m^2/\rm Hz in the vertical displacement, in the frequency range 1kHz∌10MHz1{\rm}\rm kHz\sim10 MHz. The dynamical evolution of the surface properties is also investigated. The measurement requires only a short amount of time and is essentially passive, so that it can be applied to a wide variety of surfaces.Comment: 5pp, 5 figure
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