640 research outputs found

    Thermal inertia of heavyweight traditional buildings: Experimental measurements and simulated scenarios

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    Abstract This paper discusses the results of an experimental campaign aimed to describe the thermal performance of a traditional building located in Catania, Southern Italy. The building was built in the early 1900s with traditional techniques and local materials, namely basalt stones, and is currently used for residential purposes. The results of the experimental campaign are exploited to calibrate a model for the dynamic simulation of the building with DesignBuilder. The calibrated model is then used to simulate how the same building would behave with a modern envelope made of a double leaf of bricks; other simulations take into account possible retrofit solutions, such as the installation of an insulating material either on the inner or the outer side of the walls, as well as the role of nighttime natural ventilation

    Enhanced crystallinity and film retention of P3HT thin-films for efficient organic solar cells by use of preformed nanofibers in solution

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    We report the preparation of films of poly(3-hexylthiophene) nanofibers suitable for fabrication of efficient multilayer solar cells by successive deposition of donor and acceptor layers from the same solvent. The nanofibers are obtained by addition of di-tert-butyl peroxide (DTBP) to a solution of P3HT in chlorobenzene. Interestingly, by varying the concentration of DTBP we are able to control both crystallinity and film retention of the spin-cast films. We also investigate the influence of the DTBP-induced crystallization on charge transport by thin-film transistor measurements, and find a more than five-fold increase in the hole mobility of nanofiber films compared to pure P3HT. We attribute this effect to the synergistic effects of increased crystallinity of the fibers and the formation of micrometer-sized fiber networks. We further demonstrate how it is possible to make use of the high film retention to fabricate photovoltaic devices by subsequent deposition of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) from a chlorobenzene solution on top of the nanofiber film. The presence of a relatively large crystalline phase strongly affects the diffusion behavior of PCBM into the P3HT film, resulting in a morphology which is different from that of common bulk heterojunction solar cells and resembles a bilayer structure, as can be inferred from comparison of the external quantum efficiency spectra. However, a high power conversion efficiency of 2.3% suggests that there is still a significant intermixing of the two materials taking place

    Effect of sustained-release somatotropin on performance and grazing behavior of ewes housed at different stocking rates.

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    This study evaluated the effects of recombinant bovine somatotropin (bST; one injection of 320 mg per ewe) on milk production and composition and on the grazing behavior of multiparous ewes in the third to fourth lactation. Forty Comisana lactating ewes were divided into four groups: 1) untreated, grazing on natural pasture (botanical composition: 35% of Graminaceae, 49% of Fabaceae, 6% of Cruciferae, 10% of other families) at a low stocking rate (16 m2/d); 2) untreated, grazing at a high stocking rate (8 m2/d); 3) treated with bST, grazing at a low stocking rate; and 4) treated with bST, grazing at a high stocking rate. The diets of the ewes were supplemented with vetch and oat hay (500 g/d) and with concentrate (500 g/d). Treatment increased milk production (923.8 vs. 669.5 g/d) but had little effect on fat and protein contents. Administration of bST significantly increased herbage intake; the effect on intake was more marked at the high stocking rate. Under these grazing conditions, the treated ewes reduced selective intake behavior and, thus, achieved good feed intake despite the low biomass availability

    Practical Approach to the Diagnosis of the Vulvo-Vaginal Stromal Tumors: An Overview

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    Background: The category of the "stromal tumors of the lower female genital tract" encompasses a wide spectrum of lesions with variable heterogeneity, which can be nosologically classified on the basis of their morphologic and immunohistochemical profiles as deep (aggressive) angiomyxoma (DAM), cellular angiofibroma (CAF), angiomyofibroblastoma (AMFB) or myofibroblastoma (MFB). Despite the differential diagnosis between these entities being usually straightforward, their increasingly recognized unusual morphological variants, along with the overlapping morphological and immunohistochemical features among these tumours, may raise serious differential diagnostic problems. Methods and Results: The data presented in the present paper have been retrieved from the entire published literature on the PubMed website about DAM, CAF, AFMB and MFB from 1984 to 2021. The selected articles are mainly represented by small-series, and, more rarely, single-case reports with unusual clinicopathologic features. The present review focuses on the diagnostic clues of the stromal tumours of the lower female genital tract to achieve a correct classification. The main clinicopathologic features of each single entity, emphasizing their differential diagnostic clues, are discussed and summarized in tables. Representative illustrations, including the unusual morphological variants, of each single tumour are also provided. Conclusion: Awareness by pathologists of the wide morphological and immunohistochemical spectrum exhibited by these tumours is crucial to achieve correct diagnoses and to avoid confusion with reactive conditions or other benign or malignant entities

    Maximal operators and Hilbert transforms along variable non-flat homogeneous curves

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    We prove that the maximal operator associated with variable homogeneous planar curves (t,utα)t∈R(t, u t^{\alpha})_{t\in \mathbb{R}}, α≠1\alpha\not=1 positive, is bounded on Lp(R2)L^p(\mathbb{R}^2) for each p>1p>1, under the assumption that u:R2→Ru:\mathbb{R}^2 \to \mathbb{R} is a Lipschitz function. Furthermore, we prove that the Hilbert transform associated with (t,utα)t∈R(t, ut^{\alpha})_{t\in \mathbb{R}}, α≠1\alpha\not=1 positive, is bounded on Lp(R2)L^p(\mathbb{R}^2) for each p>1p>1, under the assumption that u:R2→Ru:\mathbb{R}^2\to \mathbb{R} is a measurable function and is constant in the second variable. Our proofs rely on stationary phase methods, TT∗TT^* arguments, local smoothing estimates and a pointwise estimate for taking averages along curves.Comment: 38 page
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