654 research outputs found
the effect of discretization on the accuracy of two district heating network models based on finite difference methods
Abstract District heating and cooling (DHC) networks play a fundamental role in the transition towards a sustainable supply of heating and cooling, due to their ability to integrate any available source of thermal energy and to distribute it to the buildings. However, the use of renewable non-constant sources together with the variable heat demand of the buildings creates instable and pronounced transient operating conditions. In order to analyse the hydraulic and thermal behaviour and the dynamics occurring within these networks, several physical models based on different methods were proposed by previous researchers. Numerical thermal models based on finite difference methods (FDM) were pointed out to suffer from artificial diffusion when simulating the propagation of heat through the network. However, due to a wide and well-known literature on these methods, they are still used by many researchers and are therefore worth being investigated. The present paper analyses the effects of artificial diffusion using two models based on two different first-order approximation schemes. An ideal temperature wave and a dataset from a real DH network were used to evaluate the accuracy of the models using different discretization levels in time and space. As a result, the paper provides a framework to set a proper discretization when simulating a DHC network with FDM-based models considering both the expected accuracy and the computation time as criteria
Calibration of Plastic Phoswich Detectors for Charged Particle Detection
The response of an array of plastic phoswich detectors to ions of has been measured from =12 to 72 MeV. The detector response has been
parameterized by a three parameter fit which includes both quenching and high
energy delta-ray effects. The fits have a mean variation of with
respect to the data.Comment: 17 pages, 5 figure
Gingival lymphatic malformation. An atypical case report
Lymphatic malformations are a rare pathology that presents a highly variable clinical expression. Intraorally, it mainly affects the dorsum of the tongue. The objective of this work is to present a case of lymphatic malformation in an atypical location. A 20-year-old male who attended the clinic for multiple vesicular lesion in attached gingiva, asymptomatic and of unknown evolution. Removal of the lesion and subsequent histological analysis were performed, which showed a microcystic lymphatic vascular lesion. Immunohistochemistry for D2-40 was performed, which corroborated the lymphatic origin of the lesion. At 6 months, no recurrence of the lesion was recognized. Clinicians should include lymphatic malformations in the differential diagnosis of multiple vesicular lesions. Knowing the oral manifestations of this entity is essential for its proper diagnosis and clinical management
Fusion of radioactive Sn with Ni
Evaporation residue and fission cross sections of radioactive Sn on
Ni were measured near the Coulomb barrier. A large sub-barrier fusion
enhancement was observed. Coupled-channel calculations including inelastic
excitation of the projectile and target, and neutron transfer are in good
agreement with the measured fusion excitation function. When the change in
nuclear size and shift in barrier height are accounted for, there is no extra
fusion enhancement in Sn+Ni with respect to stable Sn+Ni.
A systematic comparison of evaporation residue cross sections for the fusion of
even Sn and Sn with Ni is presented.Comment: 9 pages, 11 figure
Inhibition of the Maillard reaction by phytochemicals composing an aqueous coffee silverskin extract via a mixed mechanism of action
This work aimed to evaluate the contribution of isoflavones and melatonin to the aqueous extract obtained from the coffee silverskin (CSE) antiglycative properties, which has not been previously studied. To achieve this goal, two model systems constituted by bovine serum albumin (BSA) and reactive carbonyls (glucose or methylglyoxal) in the presence or absence of pure phytochemicals (chlorogenic acid (CGA), genistein, and melatonin) and CSE were employed. Glucose was used to evaluate the effect on the formation of glycation products formed mainly in the early stage of the reaction, while methylglyoxal was employed for looking at the formation of advanced products of the reaction, also called methylglyoxal-derivative advanced glycation end products (AGE) or glycoxidation products. CGA inhibited the formation of fructosamine, while genistein and melatonin inhibited the formation of advanced glycation end products and protein glycoxidation. It was also observed that phenolic compounds from CSE inhibited protein glycation and glycoxidation by forming BSA-phytochemical complexes. CSE showed a significant antiglycative effect (p < 0.05). Variations in the UV-Vis spectrum and the antioxidant capacity of protein fractions suggested the formation of protein-phytochemical complexes. Fluorescence quenching and in silico analysis supported the formation of antioxidant-protein complexes. For the first time, we illustrate that isoflavones and melatonin may contribute to the antiglycative/antiglycoxidative properties associated with CSE. CGA, isoflavones, and melatonin composing CSE seem to act simultaneously by different mechanisms of actionM.R.H thanks the JAE Intro fellowship (JAEINT_15_00086) and the FPU predoctoral program of the Ministry of Science, Innovation, and Universities (FPU15/04238
A comparative study of super- and highly-deformed bands in the A ~ 60 mass region
Super- and highly-deformed rotational bands in the A ~ 60 mass region are
studied within cranked relativistic mean field theory and the
configuration-dependent shell-correction approach based on the cranked Nilsson
potential. Both approaches describe the experimental data well. Low values of
the dynamic moments of inertia J^(2) compared with the kinematic moments of
inertia J^(1) seen both in experiment and in calculations at high rotational
frequencies indicate the high energy cost to build the states at high spin and
reflect the limited angular momentum content in these configurations.Comment: 11 pages, 4 PostScript figures, Latex, uses 'epsf', submitted to
Phys. Lett.
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