1,400 research outputs found
A Marsden Type Identity for Periodic Trigonometric Splines
AbstractAn extension of Marsden′s identity for periodic trigonometric splines is obtained by a bivariate approach to that space. A basis of these spaces, whose elements have minimal or quasi-minimal support, is studied
A Paleomagnetic Inspection of the Paleocene-Eocene Thermal Maximum (PETM) in the Southern Pyrenees
Magnetic properties of rocks can be useful for determining paleoenvironmental changes. A dramatic climate change that occurred in the Paleocene-Eocene Thermal Maximum (PETM) modified the environment and, hence, the magnetic properties recorded in the sediments. New paleomagnetic data from marine records of the PETM in the Southern Pyrenean zone displays a variation of the magnetic parameters in four different sections. The magnetic signal reveals a positive excursion of magnetic values starting before the onset of the marly interval of La Faja de las Flores Mb (beginning of the PETM record, Ilerdian) in the Carriata section with a maximum value in the marly interval. A similar magnetic signal is observed in the Bujaruelo section (similar to 10 km south of Carriata at PETM times) that is related directly to the marly interval of Faja de las Flores Mb. However, towards the south, the PETM interval does not appear in the sedimentary record; therefore, in the southern Gallisue section, no magnetic excursion occurs. In the southernmost-studied Entremon section, a positive magnetic excursion occurs in a thin marly interval unrelated to the PETM, and in two lower intervals of the column. All sections were later subjected to deformation during the pyrean orogeny and the three northernmost sections in the regional cleavage front, where pressure solution and remagnetizations have been described. A post-folding remagnetization component is found in the three northern sections
Thermal comfort levels in a conditioned environment with displacement ventilation and radiant cooling floor calculated using computational fluid dynamics
In a society in continuous development, the requirements
for thermal comfort and indoor air quality are increasing.
However, these should be achieved by rational energy
consumption. With this in mind, the combined use of
displacement ventilation (DV) and radiant cooling floor (RCF)
is an innovative concept that has become popular as a cooling
system in high-rise public enclosures.
To provide a high thermal comfort, the effects of buoyancy,
supplied air temperature, air discharge angle and surface floor
temperature should be treated with special care.
Therefore, this paper presents a sensitivity analysis
considering these critical parameters in different numerical
simulations. The results of the simulations are used to calculate
the thermal comfort index, according to ISO 7730 standard, in
high ceiling enclosures using a DV + RCF system. The general
thermal sensation has been predicted using the PMV (Predicted
Mean Vote) and PPD (Predicted Percentage of Dissatisfied)
indices. The local thermal discomfort has been evaluated by
radiant temperature asymmetry, draught, vertical air
temperature differences and floor surface temperatures.
According to these indices, the classification of Category A is
reached using DV + RCF system, exception of the radiant
temperature asymmetry index. That fact will be discussed in
detail, analyzed the suitability of the calculation indicates in
ISO 7730 for systems involved in radiating surfaces.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016
An analytical approach to the design of liquid crystal microlenses
[Poster of]: 40th Topical Meeting on Liquid Crystals, Paderborn from March 20th-22nd, 2013.New analytical expressions for designing liquid crystal microlenses have been proposed. Equations involved, based on a novel equivalent electric circuit, lead to optimum designs of liquid crystal lenses which lens diameter ranges from few micrometers to one millimeter. A particular mathematical relationship between the microlens thickness and diameter is the key parameter to achieving a quasi-parabolic phase distribution across the microlens diameter. Frank-Oseen equations have been used for modeling and solving the problem. A solution for the elastic constants of a hypothetic liquid crystal, proper for a microlens device, is proposed. Manufacturing parameters of the lenses have been designed for fulfilling focal length and diameter requirements. Some of them are the thickness, the electrode configuration, and the driving scheme (modal or hole patterned). A set of liquid crystal microlenses has been manufactured and an electrooptic characterization has been carried out in order to compare the measurements with the analytical approach.This work was supported in part by the “Ministerio de Ciencia e Innovación” of Spain
(grant no.TEC2009-13991-C02-01) and Comunidad de Madrid (grant no. FACTOTEM2
S2009/ESP-1781).No publicad
Micro-optical phase modulators based on liquid crystal technology
[Poster of]: ¿SINFOTONes en el Año de la Luz?: Reunión de Jóvenes Investigadores SINFOTON: 1ª Feria de Otoño 2015, 23 de Octubre.An optical phase modulator is an optical element used to control the phase of light. They have
multiple applications, for example ophthalmological applications, tunable zooms, beam steering,
correction of aberrations, astronomy, 3D vision applications, etc. The displays and photonics
application group (GDAF) of Carlos III university of Madrid (UC3M) in collaboration with CEMDATIC
of Polytechnic University of Madrid (UPM) have extended the knowledge in this field by the proposal
of several advanced micro-optical phase modulators. These, obtain with simply topologies either
common optical elements, e.g. microlenses for autostereoscopic devices [1], aberration controllers
for rectangular micro-optical elements [2] and microlenses with reduced aberrations and tunable
rotation [3], or singular optical elements, e.g. micro-axicon arrays [3] and tunable optical vortices [5].TEC2013-47342-C2-2-R and SINFOTON S2013/MIT-2790Publicad
Provenance and tectonic setting of the Paleozoic Tamatán Group, NE Mexico: Implications for the closure of the Rheic Ocean
The Huizachal–Peregrina Anticlinorium in northeastern Mexico comprises a wide variety of Precambrian
and Paleozoic basement units. In this work, Silurian-to-Permian unmetamorphosed siliciclastic successions (i.e., Cañón de Caballeros, Vicente Guerrero, Del Monte, and Guacamaya formations) forming the
Tamatán Group is described; the group overlies the Novillo metamorphic complex, which is the northernmost exposed region of the Oaxaquia microcontinent. In this paper, a provenance model for the
Tamatán Group is proposed based on new petrological data, whole-rock geochemical data, and U–Pb
LA-ICP-MS detrital zircon age data from these marine fossiliferous strata. The results show a shallowmarine to deep-water clastic succession classified as feldspatho-lithic-quartzose and litho-feldspathoquartzose (Cañón de Caballeros and Vicente Guerrero formations) and feldspatho-quartzo-lithic and
litho-quartzo-feldspathic (Del Monte and Guacamaya formations). The petrological and geochemical
data indicate a derivation from felsitic, intermediate, and basic rocks, intense to moderate weathering,
and high to moderate recycling of the source area. The geochronological data can be organized into
three main detrital zircon U–Pb age groups: (1) a Meso-Neoproterozoic group, likely derived from
Oaxaquia and the Maya block, which is also the probable source of 1.5–1.6 Ga zircon grains; (2) an
Ordovician–Silurian group that is likely sourced by igneous Maya Block intrusions or from local units
such as the Ordovician Peregrina Tonalite; and (3) Pennsylvanian and Permian zircon that can be derived
from magmatic arc-related intrusions from the diachronous Rheic closure. Additionally, major, trace, and
rare earth element concentrations and ratios from the Tamatán Group indicate a passive margin that
evolved into magmatic arc sources within the upper continental crust. The integration of our data indicates that the Tamatán Group was deposited in an unreported back-arc basin from the northernmost
part of Oaxaquia near the Maya Block along the northwestern Gondwanan margin during the closure
of the Rheic Ocean priori to complete Pangea
Avoidable Adverse Events Related to Ignoring the Do-Not-Do Recommendations: A Retrospective Cohort Study Conducted in the Spanish Primary Care Setting
Objective This study aimed to measure the frequency and severity of avoidable adverse events (AAEs) related to ignoring do-not-do recommendations (DNDs) in primary care. Methods A retrospective cohort study analyzing the frequency and severity of AAEs related to ignoring DNDs (7 from family medicine and 3 from pediatrics) was conducted in Spain. Data were randomly extracted from computerized electronic medical records by a total of 20 general practitioners and 5 pediatricians acting as reviewers; data between February 2018 and September 2019 were analyzed. Results A total of 2557 records of adult and pediatric patients were reviewed. There were 1859 (72.7%) of 2557 (95% confidence interval [CI], 71.0%-74.4%) DNDs actions in 1307 patients (1507 were performed by general practitioners and 352 by pediatricians). Do-not-do recommendations were ignored more often in female patients (P < 0.0001). Sixty-nine AAEs were linked to ignoring DNDs (69/1307 [5.3%]; 95% CI, 4.1%-6.5%). Of those, 54 (5.1%) of 1062 were in adult patients (95% CI, 3.8%-6.4%) and 15 (6.1%) of 245 in pediatric patients (95% CI, 3.1%-9.1%). In adult patients, the majority of AAEs (51/901 [5.7%]; 95% CI, 4.2%-7.2%) occurred in patients 65 years or older. Most AAEs were characterized by temporary minor harm both in adult patients (28/54 [51.9%]; 95% CI, 38.5%-65.2%) and pediatric patients (15/15 [100%]). Conclusions These findings provide a new perspective about the consequences of low-value practices for the patients and the health care systems. Ignoring DNDs could place patients at risk, and their safety might be unnecessarily compromised
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