Theoretical and experimental study of AC loss in HTS single pancake coils

The electromagnetic properties of a pancake coil in AC regime as a function of the number of turns is studied theoretically and experimentally. Specifically, the AC loss, the coil critical current and the voltage signal are discussed. The coils are made of Bi2Sr2Ca2Cu3O10/Ag (BiSCCO) tape, although the main qualitative results are also applicable to other kinds of superconducting tapes, such as coated conductors. The AC loss and the voltage signal are electrically measured using different pick up coils with the help of a transformer. One of them avoids dealing with the huge coil inductance. Besides, the critical current of the coils is experimentally determined by conventional DC measurements. Furthermore, the critical current, the AC loss and the voltage signal are simulated, showing a good agreement with the experiments. For all simulations, the field dependent critical current density inferred from DC measurements on a short tape sample is taken into account.Comment: 22 pages, 15 figures; contents extended (sections 3.2 and 4); one new figure (figure 5) and two figures replaced (figures 3 and 8); typos corrected; title change

Value dimensions and relationship postures in dyadic 'key relationship programmes'

Business-to-business marketing is often concerned with the way in which companies manage strategically important relationships with their counterparts: their Key Relationship Programmes (KRPs). These relationships can be managed through the implementation of specific managerial and organisational structures, commonly implemented via Key Account Programmes (on the supplier side) or Key Supplier Programmes (on the customer side). Underlying this managerial process is an implicit assumption that these important relationships bring some form of additional value to one or both parties involved. However, a dyadic view of how this value is created and shared between the parties remains an under-researched area. In this conceptual paper, we use the multi-faceted value construct introduced in Pardo et al. (2006) and posit that the buyer's or seller's value strategies can be best understood as being internally, exchange, or relationship based. This in turn allows us to analyse the value gained as being the outcome of one of nine generic key relationship postures within any dyadic KRP. We focus on an analysis of so-called "managed" relationship postures and identify a number of dyadic activities and competencies that we hypothesise are important in managing such KRPs, and which can form the basis for further empirical research

Rotura cuadricipital en edad pediátrica

La rotura del tendón del cuádriceps es una patología característica de la edad adulta, siendo excepcional en la infancia. Se presenta el caso de un niño de 9 años con una gonalgia izquierda de 2 meses de evolución sin claro antecedente traumático. Se realiza Resonancia Magnética, que establece el diagnóstico de rotura parcial del tendón del cuádriceps. Se decide reanclaje del mismo en el polo superior de la rótula, seguido de rehabilitación. Después del tratamiento quirúrgico realizado el paciente recupera el balance articular y muscular. La rotura del tendón del cuádriceps es excepcional en la edad pediátrica. La realización de una buena exploración, tanto clínica como radiológica es fundamental. El tratamiento viene determinado por el tipo de rotura y la clínica asociada. Hemos realizado una revisión bibliográfica de la literatura con el fin de dar a conocer este tipo de patología y su manejo.Rupture of the quadriceps tendon is a common pathology in adults, but exceptionally rare in children. The case reported is that of a 9-year old boy with a 2-month history of pain in the left knee without any clear history of trauma. Magnetic Resonance Imaging study was carried out, leading to the diagnosis of partial tear of the left quadricipital tendon. The tendon was re-anchored at the upper pole of the patella, followed by rehabilitation. The patient recovered joint and muscular balance after the surgery. Rupture of the quadriceps tendon is exceptionally rare at pediatric ages. A thorough examination, both clinical as well as radiological, is of fundamental importance. Treatment is determined by the kind of rupture and associated clinical symptoms. We have carried out a bibliographical review of the literature in order to offer a better understanding of this pathology and its treatment

3D Modeling of the Magnetization of Superconducting Rectangular-Based Bulks and Tape Stacks

In recent years, numerical models have become popular and powerful tools to investigate the electromagnetic behavior of superconductors. One domain where this advances are most necessary is the 3D modeling of the electromagnetic behavior of superconductors. For this purpose, a benchmark problem consisting of superconducting cube subjected to an AC magnetic field perpendicular to one of its faces has been recently defined and successfully solved. In this work, a situation more relevant for applications is investigated: a superconducting parallelepiped bulk with the magnetic field parallel to two of its faces and making an angle with the other one without and with a further constraint on the possible directions of the current. The latter constraint can be used to model the magnetization of a stack of high-temperature superconductor tapes, which are electrically insulated in one direction. For the present study three different numerical approaches are used: the Minimum Electro-Magnetic Entropy Production (MEMEP) method, the $H$-formulation of Maxwell's equations and the Volume Integral Method (VIM) for 3D eddy currents computation. The results in terms of current density profiles and energy dissipation are compared, and the differences in the two situations of unconstrained and constrained current flow are pointed out. In addition, various technical issues related to the 3D modeling of superconductors are discussed and information about the computational effort required by each model is provided. This works constitutes a concrete result of the collaborative effort taking place within the HTS numerical modeling community and will hopefully serve as a stepping stone for future joint investigations

Clues to NaCN formation

ALMA is providing us essential information on where certain molecules form. Observing where these molecules emission arises from, the physical conditions of the gas, and how this relates with the presence of other species allows us to understand the formation of many species, and to significantly improve our knowledge of the chemistry that occurs in the space. We studied the molecular distribution of NaCN around IRC +10216, a molecule detected previously, but whose origin is not clear. High angular resolution maps allow us to model the abundance distribution of this molecule and check suggested formation paths. We modeled the emission of NaCN assuming local thermal equilibrium (LTE) conditions. These profiles were fitted to azimuthal averaged intensity profiles to obtain an abundance distribution of NaCN. We found that the presence of NaCN seems compatible with the presence of CN, probably as a result of the photodissociation of HCN, in the inner layers of the ejecta of IRC +10216. However, similar as for CH 3 CN, current photochemical models fail to reproduce this CN reservoir. We also found that the abundance peak of NaCN appears at a radius of 3 x 10 15 cm, approximately where the abundance of NaCl, suggested to be the parent species, starts to decay. However, the abundance ratio shows that the NaCl abundance is lower than that obtained for NaCN. We expect that the LTE assumption might result in NaCN abundances higher than the real ones. Updated photochemical models, collisional rates, and reaction rates are essential to determine the possible paths of the NaCN formation.Comment: 7 pages, 10 figures. Accepted for publication in A&A letter

Goal-oriented adaptivity for a conforming residual minimization method in a dual discontinuous Galerkin norm

We propose a goal-oriented mesh-adaptive algorithm for a finite element method stabilized via residual minimization on dual discontinuous-Galerkin norms. By solving a saddle-point problem, this residual minimization delivers a stable continuous approximation to the solution on each mesh instance and a residual projection onto a broken polynomial space, which is a robust error estimator to minimize the discrete energy norm via automatic mesh refinement. In this work, we propose and analyze a goal-oriented adaptive algorithm for this stable residual minimization. We solve the primal and adjoint problems considering the same saddle-point formulation and different right-hand sides. By solving a third stable problem, we obtain two efficient error estimates to guide goal oriented adaptivity. We illustrate the performance of this goal-oriented adaptive strategy on advection-diffusion reaction problems

Temperature oscillations of magnetization observed in nanofluid ferromagnetic graphite

We report on unusual magnetic properties observed in the nanofluid room-temperature ferromagnetic graphite (with an average particle size of l=10nm). More precisely, the measured magnetization exhibits a low-temperature anomaly (attributed to manifestation of finite size effects below the quantum temperature) as well as pronounced temperature oscillations above T=50K (attributed to manifestation of the hard-sphere type pair correlations between ferromagnetic particles in the nanofluid)

Valuasi Ekonomi Kayu dan Kesejukan Kawasan Arboretum Universitas Riau

Forest has such great benefits for life. Various tangible and intangible benefit that can be obtained from the forest can also be optained from the arboretum. Although basicly arboretum serves as a means of education. Tangible and intangible benefits that could potentially be produced is still rate as low, causing excessive exploitation. Assessment the benefits of trees on a place at the price of economic value necessary to considen improve the bargaining position and transforming into economic value of money. The presence of trees also affect the micro climate (value coolness) around the arboretum. Becomes a problem when the arboretum was damaged because it was not able to provide coolness around the arboretum. The research was conducted in the arboretum area of Riau University Pekanbaru on December 2015. The purpose of this research was to determine the economic value of trees in the arboretum area of Riau University and determine the economic value of the coolness in the arboretum area of Riau University. The research result showed that the economic value of wood in Riau University arboretum is Rp. 951.852.785,54 and the economic value of coolness in Riau University arboretum is Rp 23.875.000.000