Design and Evaluation of a 3D Printed Filar Micrometer

Background Double stars are celestial objects that allow for calculating the mass of stars by assessing their orbits. Stellar mass affects every current model of stellar evolution, but the most accurate double star orbits can take decades to record. Due to the long-term nature of such observations and lack of groundbreaking research in double star studies, professional astronomers are no longer focused on making these measurements, so amateur astronomers can pick up where professionals have left off. Amateurs can only do this if they can get the equipment that they need at prices they can afford. A personally-manufactured filar micrometer could fill this need. Astronomers use a filar micrometer paired with a telescope to take visual double star measurements. Unfortunately, current commercial filar micrometers are cost prohibitive for most amateur astronomers. This project sought to design, 3D print, test, and calibrate a filar micrometer that amateur astronomers could produce cost effectively. Methods Creo Parametric 3.0 and a ProJet MJP 3600 Series 3D printer were used to design and print the filar micrometer. A Fowler 1-2” digital counter micrometer, 54-gauge Nichrome 80 wire, and a 6” Orion SkyQuest Dobsonian telescope were used with the printed filar micrometer to take measurements. The measurements were of the separation between components of an artificial double star created by flashlights reflected in a bearing ball. These measurements were used to calibrate the filar micrometer and find the preliminary accuracy of the filar micrometer. Results Twenty-one measurements were taken of three different arrangements of the artificial double star. The average calibration calculated from this data is 1.44E-4 inches per arcsecond. Measurements of the 24 Coronae Borealis simulated star (with a separation of 20.14 arcseconds) produced a seventeen percent error with an average measured separation of 16.74 arcseconds. Conclusion Though there is no firm standard, according to multiple sources a professionalquality filar micrometer should be capable of precision to one tenth of an arcsecond when measuring close double stars or one arcsecond for wider double stars. The filar micrometer produced in this project is capable (by design) of precision to seven tenths of an arcsecond. This means that it cannot reach the accuracy of the very few professional filar micrometers available for resale when measuring close double stars. However, at a tenth of the cost of the professionally-produced version, it is an affordable amateur filar micrometer. Since these are preliminary values for the calibration and accuracy of the produced filar micrometer, future data collection in these areas will lead to a better view of the true calibration value and accuracy possible for this filar micrometer

Observation of a tricritical wedge filling transition in the 3D Ising model

In this Letter we present evidences of the occurrence of a tricritical filling transition for an Ising model in a linear wedge. We perform Monte Carlo simulations in a double wedge where antisymmetric fields act at the top and bottom wedges, decorated with specific field acting only along the wegde axes. A finite-size scaling analysis of these simulations shows a novel critical phenomenon, which is distinct from the critical filling. We adapt to tricritical filling the phenomenological theory which successfully was applied to the finite-size analysis of the critical filling in this geometry, observing good agreement between the simulations and the theoretical predictions for tricritical filling.Comment: 5 pages, 3 figure

Density functional theory study of the nematic-isotropic transition in an hybrid cell

We have employed the Density Functional Theory formalism to investigate the nematic-isotropic capillary transitions of a nematogen confined by walls that favor antagonist orientations to the liquid crystal molecules (hybrid cell). We analyse the behavior of the capillary transition as a function of the fluid-substrate interactions and the pore width. In addition to the usual capillary transition between isotropic-like to nematic-like states, we find that this transition can be suppressed when one substrate is wet by the isotropic phase and the other by the nematic phase. Under this condition the system presents interface-like states which allow to continuously transform the nematic-like phase to the isotropic-like phase without undergoing a phase transition. Two different mechanisms for the disappearance of the capillary transition are identified. When the director of the nematic-like state is homogeneously planar-anchored with respect to the substrates, the capillary transition ends up in a critical point. This scenario is analogous to the observed in Ising models when confined in slit pores with opposing surface fields which have critical wetting transitions. When the nematic-like state has a linearly distorted director field, the capillary transition continuously transforms in a transition between two nematic-like states.Comment: 31 pages, 10 figures, submitted to J. Chem. Phy

Los mensajes filatélicos contra la violencia hacia las mujeres

Objetivo: conocer la difusión mundial de sellos postales con mensajes contra la violencia hacia la mujer y describir sus elementos iconográficos. Material y método: consulta del catálogo Yvert et Tellier 2017 para la búsqueda de sellos sobre campañas contra la violencia hacia las mujeres. Análisis descriptivos de los sellos según la metodología de Panofsky. Se analizaron las imágenes en su contexto y se relacionaron con el momento y el motivo de la emisión del sello. Resultados: entre los años 1985 y 2017, se localizaron 126 sellos: 40 en Europa, 53 en América, 19 en África, 11 en Asia y 3 en Oceanía. La mayoría contiene leyendas con mensajes contra la violencia hacia la mujer. La simbología utilizada incluye: la paloma blanca (paz), el lazo violeta (denuncia contra la violencia), el lazo blanco (denuncia masculina contra la violencia), manos extendidas (alto a la violencia), flores blancas (inocencia o pureza), cadenas (esclavitud), llanto (sufrimiento), ojos tapados (privación de derechos), mariposa (libertad), la imagen de la diosa de la justicia y la relación entre símbolos masculinos y femeninos (igualdad). Asimismo, se localizaron sellos de mutilación genital, que aluden al tráfico de mujeres para la explotación sexual; en homenaje a personajes representativos de la lucha contra la violencia; y sellos que muestran recursos institucionales de soporte. Conclusiones: la representación de la violencia de género está presente en una gran cantidad de países, sobre todo de Europa y América. Los sellos pretenden concienciar a la sociedad sobre esta lacra social e insistir en la importancia de la educación para prevenir toda forma de violencia contra la mujer

Distance bound smoothing under orientation constraints

Trabajo presentado al ICRA celebrado en Seattle (US) del 26 al 30 de mayo de 2015.Distance Bound Smoothing (DBS) is a basic operation originally developed in Computational Chemistry to determine point configurations that are within certain pairwise ranges of distances. This operation consist in the iterative application of filtering processes that reduce the given ranges using triangular and tetrangular inequalities. Standard DBS has a limited range of applications because it does not take into account constraints on the orientations of simplices (triangles or tetrahedra, depending on the dimension of the problem). This paper discusses an extension of DBS that permits incorporating these constraints. This paves the way for the application of DBS techniques to a broad range of problems in Robotics.This work has been partially supported by by the Spanish Ministry of Economy and Competitiveness under project DPI2014-57220-C2-2-PPeer Reviewe

Corrosión por nido de hormigas de tubos de cobre utilizados en sistemas de aire acondicionado

15 pages, 12 figures, 3 tables.[EN] Ant-nest corrosion is a specific type of premature failure (2-3 months) of copper tubes used in air-conditioning units causing the loss of refrigerant liquid and the consequent environment pollution. It is known that attack requires the simultaneous presence of moisture, oxygen and a corrodent, usually an organic acid, such as formic, acetic, propionic or butyric acid or other volatile organic substances like methanol, ethanol, formaldehyde or acetoaldehyde. Approximately 10% of all premature failures of copper tubes used in the heating, ventilation and air-conditioning (HVAC) industry are the result of ant-nest corrosion. This type of corrosion usually occurs in thin-wall copper pipes, especially when copper is de-sulphurised, and is known by several names: formicary corrosion, unusual corrosion, branched pits, pinhole corrosion, etc.[ES] Corrosión por “nido de hormigas” es un tipo específico de fallo prematuro (2-3 meses) que tiene lugar en tubos de cobre utilizados en sistemas de aire acondicionado originando la pérdida de líquido refrigerante y la consecuente contaminación ambiental. Es conocido que este tipo de ataque requiere la presencia simultánea de humedad, oxígeno y un medio agresivo, habitualmente un ácido orgánico, como fórmico, acético, propiónico o butírico u otras sustancias orgánicas volátiles tales como metanol, etanol, formaldehido o acetoaldehido. Aproximadamente el 10% de los fallos prematuros en tubos de cobre utilizados en calefacción, ventilación y en la industria de aire acondicionado son el resultado de corrosión por nido de hormigas. Frecuentemente, este tipo de corrosión tiene lugar en tubos de cobre de pared delgada, especialmente cuando el cobre es del tipo desulfurizado, y se conoce con varios nombres: corrosión por ácido fórmico, corrosión no habitual, picaduras ramificadas, corrosión con forma de alfiler, etc.The authors express their gratitude to the International Copper Association (ICA) Ltd. (New York) and to the Centre for Advanced Interdisciplinary Research in Materials (CIMAT) (Chile) for financial support under Project No. TEK-1023-9.Peer reviewe

Corrosión por nido de hormigas de tubos de cobre utilizados en sistemas de aire acondicionado

15 pages, 12 figures, 3 tables.[EN] Ant-nest corrosion is a specific type of premature failure (2-3 months) of copper tubes used in air-conditioning units causing the loss of refrigerant liquid and the consequent environment pollution. It is known that attack requires the simultaneous presence of moisture, oxygen and a corrodent, usually an organic acid, such as formic, acetic, propionic or butyric acid or other volatile organic substances like methanol, ethanol, formaldehyde or acetoaldehyde. Approximately 10% of all premature failures of copper tubes used in the heating, ventilation and air-conditioning (HVAC) industry are the result of ant-nest corrosion. This type of corrosion usually occurs in thin-wall copper pipes, especially when copper is de-sulphurised, and is known by several names: formicary corrosion, unusual corrosion, branched pits, pinhole corrosion, etc.[ES] Corrosión por “nido de hormigas” es un tipo específico de fallo prematuro (2-3 meses) que tiene lugar en tubos de cobre utilizados en sistemas de aire acondicionado originando la pérdida de líquido refrigerante y la consecuente contaminación ambiental. Es conocido que este tipo de ataque requiere la presencia simultánea de humedad, oxígeno y un medio agresivo, habitualmente un ácido orgánico, como fórmico, acético, propiónico o butírico u otras sustancias orgánicas volátiles tales como metanol, etanol, formaldehido o acetoaldehido. Aproximadamente el 10% de los fallos prematuros en tubos de cobre utilizados en calefacción, ventilación y en la industria de aire acondicionado son el resultado de corrosión por nido de hormigas. Frecuentemente, este tipo de corrosión tiene lugar en tubos de cobre de pared delgada, especialmente cuando el cobre es del tipo desulfurizado, y se conoce con varios nombres: corrosión por ácido fórmico, corrosión no habitual, picaduras ramificadas, corrosión con forma de alfiler, etc.The authors express their gratitude to the International Copper Association (ICA) Ltd. (New York) and to the Centre for Advanced Interdisciplinary Research in Materials (CIMAT) (Chile) for financial support under Project No. TEK-1023-9.Peer reviewe

Bilayered smectic phase polymorphism in the dipolar Gay-Berne liquid crystal model

We present computer simulations of the Gay–Berne model with a strong terminal dipole. We report the existence of different stable antiferroelectric interdigitated bilayered phases in this model with diverse in-plane organization. The occurrence of these phases depends crucially on the value of the molecular elongation . For = 3 we find an interdigitated bilayered smectic-A phase absent when there is no dipole and a bilayered smectic-T or crystal with positional in-plane tetragonal ordering, different from the hexatic observed in the absence of the molecular dipole. For =4, bilayered smectic-A and in-plane hexatic-ordered smectic-B or crystal phases are observe

On the presence of fertile gametophytes of <i>Padina pavonica</i> (Dictyotales, Phaeophyceae) from the Iberian coasts

The gametophytes of <em>Padina pavonica</em> (L.) Thivy have received little attention in literature. Both female and predominantly male monoecious gametophytes of <em>P. pavonica</em> are recorded for the first time in the Iberian Peninsula. A detailed description of the morphology and the disposition of oogonia and antheridia is presented. In addition, a comparison with literature data on this and other <em>Padina</em> species is carried out.<br><br>Los gametófitos de <em>Padina pavonica</em> (L.) Thivy han sido escasamente reseñados en la bibliografía. En este trabajo se señala por primera vez en las costas de la Península Ibérica la presencia de gametófitos fértiles de <em>P. pavonica</em>, tanto femeninos como monoicos predominantemente masculinos. Se presenta una detallada descripción de la disposición y la morfología de los oogonios y anteridios. Asimismo, se realiza una comparación con los datos bibliográficos de esta especie y con los de otras especies de <em>Padina</em

Increased placental expression and maternal serum levels of apoptosis-inducing TRAIL in recurrent miscarriage

AbstractIntroductionRecurrent miscarriage (RM; ≥3 consecutive pregnancy losses) occurs in 1–3% of fertile couples. No biomarkers with high predictive value of threatening miscarriage have been identified. We aimed to profile whole-genome differential gene expression in RM placental tissue, and to determine the protein levels of identified loci in maternal sera in early pregnancy.MethodsGeneChips (Affymetrix®) were used for discovery and Taqman RT-qPCR assays for replication of mRNA expression in placentas from RM cases (n = 13) compared to uncomplicated pregnancies matched for gestational age (n = 23). Concentrations of soluble TRAIL (sTRAIL) and calprotectin in maternal serum in normal first trimester (n = 35) and failed pregnancies (early miscarriage, n = 18, late miscarriage, n = 4; tubal pregnancy, n = 11) were determined using ELISA.ResultsIn RM placentas 30 differentially expressed (with nominal P-value < 0.05) transcripts were identified. Significantly increased placental mRNA expression of TNF-related apoptosis-inducing ligand (TRAIL; P = 1.4 × 10−3; fold-change 1.68) and S100A8 (P = 7.9 × 10−4; fold-change 2.56) encoding for inflammatory marker calprotectin (S100A8/A9) was confirmed by RT-qPCR. When compared to normal first trimester pregnancy (sTRAIL 16.1 ± 1.6 pg/ml), significantly higher maternal serum concentration of sTRAIL was detected at the RM event (33.6 ± 4.3 pg/ml, P = 0.00027), and in pregnant women, who developed an unpredicted miscarriage 2–50 days after prospective serum sampling (28.5 ± 4.4 pg/ml, P = 0.039). Women with tubal pregnancy also exhibited elevated sTRAIL (30.5 ± 3.9 pg/ml, P = 0.035). Maternal serum levels of calprotectin were neither diagnostic nor prognostic to early pregnancy failures (P > 0.05).ConclusionsThe study indicated of sTRAIL as a potential predictive biomarker in maternal serum for early pregnancy complications