Изменения высоты поверхности и баланс массы ледникового купола Академии Наук на Северной Земле

We have determined the surface-elevation change rates of the Academy of Sciences Ice Cap, Severnaya Zemlya, Russian Arctic, for two different periods: 2004–2016 and 2012/2013–2016. The former was calculated from differencing of ICESat and ArcticDEM digital elevation models, while the latter was obtained by differencing two sets of ArcticDEM digital elevation models. From these surface-elevation change rates we obtained the geodetic mass balance, which was nearly identical for both periods, at −1,72±0,67 Gt a−1, equivalent to −0,31±0,12 m w.e. a−1 over the whole ice cap area. Using an independent estimate of frontal ablation for 2016−2017 of −1,93±0,12 Gt a−1 (−0,31±0,12 m w.e. a−1), we get an estimate of the climatic mass balance not significantly different from zero, at 0,21±0,68 Gt a−1 (0,04±0,13 m w.e. a−1), which agrees with the near-zero average balance at a decadal scale observed during the last four decades. Making an observationally-based assumption on accumulation rate, we estimate the current total ablation from the ice cap, and its partitioning between frontal ablation, dominated by calving (~54%) and climatic mass balance, mostly surface ablation (~46%).На основе разновременных ЦМР установлены скорости изменения высоты поверхности ледникового купола Академии Наук на Северной Земле за два периода: 2004−2016 и 2012/2013−2016 гг. и определён геодезический баланс его массы (−1,72±0,67 Гт/год). Сделан расчёт климатического баланса массы (0,21±0,68 Гт/год) и полной абляции (−3,18 Гт/год) ледника, где на отёл приходится ≈54%, а на поверхностную абляцию – ≈46%

Поверхностные скорости и айсберговый сток ледникового купола Академии Наук на Северной Земле

We have determined the ice-surface velocities of the Academy of Sciences Ice Cap, Severnaya Zemlya, Russian Arctic, during the period November 2016 – November 2017, using intensity offset-tracking of Sentinel-1 synthetic-aperture radar images. We used the average of 54 pairs of weekly velocities (with both images in each pair separated by a12-day period) to estimate the mean annual ice discharge from the ice cap. We got an average ice discharge for 2016–2017 of 1,93±0,12 Gt a−1, which is equivalent to −0,35±0,02 m w.e. a−1 over the whole area of the ice cap. The difference from an estimate of ~1,4 Gt a−1 for 2003–2009 can be attributed to the initiation of ice-stream flow in Basin BC sometime between 2002 and 2016. Since the front position changes between both periods have been negligible, ice discharge is equivalent to calving flux. We compare our results for calving flux with those of previous studies and analyse the possible drivers of the changes observed along the last three decades. Since these changes do not appear to have responded to environmental changes, we conclude that the observed changes are likely driven by the intrinsic characteristics of the ice cap governing tidewater glacier dynamics.По 54 парам космических снимков Sentinel‐1, сделанных с ноября 2016 г. по ноябрь 2017 г., определены скорости движения ледникового купола Академии Наук на Северной Земле. На этой основе оценён среднегодовой расход льда в море этого купола (1,93±0,12 Гт/год), установлены основные пути стока льда, проведено сравнение с прежними оценками

Disseny d'una peça de plàstic reciclat: Metodologia i aplicació

El disseny d'una peça de plàstic és un procés complex que implica el coneixement de les característiques mecàniques, elèctriques i físiques de la peça, i també dels processos de transformació. La principal tasca del dissenyador és traduir una sèrie de requeriments i idees prèvies en les dimensions i formes finals de la peça. Per aconseguir-ho de manera òptima, el dissenyador ha de fer ús, a banda de l'experiència i els coneixements propis, d'una metodologia de disseny adquada. L'objectiu d'aquest article és posar de manifest els passos a seguir quan s'aborda un disseny i la seva aplicació a una peça de plàstic fabricada en material reciclat

Diseño de una pieza de plástico reciclado: Metodología y aplicación

El mecanismo por el que se diseña una pieza de plástico es un proceso complejo que implica el conocimiento de las características mecánicas, eléctricas y físicas de la pieza y también de los procesos de transformación. La principal tarea del diseñador es traducir una serie de requerimientos e ideas previas en las direcciones y formas finales que tendrá la pieza. Para conseguirlo de forma optimizada el diseñador debe hacer uso de su experiencia, conocimientos y de una metodología de diseño adecuada. El objeto de este trabajo es poner de manifiesto los pasos a seguir cuando se aborda un diseño y la aplicación a una pieza de plástico fabricada en material reciclad

Evaluación del comportamiento mecánico de capas bituminosas ultra delgadas como una adecuada estrategia para la rehabilitación de pavimentos urbanos

Very Thin Asphalt Overlay (VTAO) has been introduced as an alternative to traditional thick overlays, seal coats, and micro-surfacings. Nonetheless, there are some challenges that still remain regarding the application of VTAOs (such as mixture type, cohesiveness, wear resistance, cracking and durability), particularly in heavy traffic urban areas. Therefore, this paper presents an extensive comparative evaluation of the mechanical performance, durability and safety issues (cohesiveness, adhesiveness, ageing, cracking, plastic deformation, permeability, macrotexture, skid and wear resistance, and fuel resistance) of a VTAO (20 mm thick) and a high performance BBTM 11B (35 mm thick), commonly used as an open-graded mixture for pavement overlays. The results demonstrated that VTAO is an appropriate material for urban pavements as it provides good durability and resistance to the propagation of defects. Nonetheless, further studies are required to improve its behavior under distresses related to plastic deformations and safety properties.Las capas bituminosas ultra delgadas para rehabilitación superficial de carreteras son una alternativa a las tradicionales capas asfálticas, riegos bituminosos y micro-aglomerados. No obstante, aún son numerosos los aspectos a estudiar para la generalización de su uso, particularmente en zonas urbanas con elevado tráfico. Así, este artículo recoge un análisis comparativo del comportamiento mecánico, durabilidad y factores de seguridad (evaluando parámetros como cohesividad, adhevisvidad, envejecimiento, fisuración, deformaciones, permeabilidad, macrotextura, y resistencia al deslizamiento, al desgaste y a los combustibles) entre una capa delgada de 20 mm de espesor, y una mezcla discontinua de altas prestaciones (BBTM-11B con 35 mm), comúnmente utilizada en capas de rodadura. Los resultados indican que puede ser una adecuada solución para pavimentos urbanos dada su durabilidad y resistencia a la propagación de fallos. No obstante, se requieren futuros estudios centrados en la mejora de parámetros de seguridad y de su resistencia a las deformaciones permanentes

Lucro líquido do franqueado: um sinal para a escolha de franquia em época de crise

Este artículo aborda desde la perspectiva de la Teoría de Señales la elección de una franquicia por un potencial franquiciado que elige este canal de distribución por primera vez. El objetivo es analizar la relación entre algunas señales enviadas por el franquiciador y la elección de una franquicia por el potencial franquiciado. Concluimos que los efectos de las variables macroeconómicas de España en el periodo 2006-2013 influyeron en los ingresos netos de los franquiciados para que se convirtiera en una señal empleada por éstos a la hora de elegir la franquicia donde abrir un establecimiento.This paper adopts the perspective of Theory of Signals to discuss how someone starting a business as a franchisee for the first time can choose a suitable franchise brand. The aim was to analyze the relationship between certain signals sent by the franchisor and the choice of a franchise brand by the prospective franchisee. Using panel data, we found that the effects of macroeconomic variables in Spain for the 2006-2013 crisis period influenced franchisees' net income, which thus became a relevant signal in their process of choosing a franchise brand to start a business.Sob a perspectiva da Teoria de Sinais, este artigo aborda a seleção de uma franquia por um franqueado que elege esse potencial canal de distribuição pela primeira vez. O objetivo é analisar a relação entre alguns sinais enviados pelo franqueador e a escolha de uma franquia pelo potencial franqueado. Usando a metodologia de dados em painel, os resultados obtidos nos permitiram concluir que os efeitos das variáveis macroeconômicas da Espanha no período de crise econômica (2006-2013) influenciaram as receitas líquidas dos franqueados, tornando-se um sinal para eles elegerem onde abrir um estabelecimento franqueado

The Pierre Auger Observatory III: Other Astrophysical Observations

Astrophysical observations of ultra-high-energy cosmic rays with the Pierre Auger ObservatoryComment: Contributions to the 32nd International Cosmic Ray Conference, Beijing, China, August 201

Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV

We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/- 0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.Comment: Accepted for publication by PR

The Pierre Auger Observatory: Contributions to the 34th International Cosmic Ray Conference (ICRC 2015)

Contributions of the Pierre Auger Collaboration to the 34th International Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The NetherlandsComment: 24 proceedings, the 34th International Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The Netherlands; will appear in PoS(ICRC2015

Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic