scholarly journals Decay of a long-term monitored glacier: the Careser glacier (Ortles-Cevedale, European Alps)

2013 ◽  
Vol 7 (4) ◽  
pp. 3293-3335 ◽  
Author(s):  
L. Carturan ◽  
C. Baroni ◽  
M. Becker ◽  
A. Bellin ◽  
O. Cainelli ◽  
...  
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
European Alps ◽  
Systematic Observation ◽  
Average Mass ◽  
Observation Series ◽  
Area And Volume

Abstract. The continuation of valuable, long-term glacier observation series is threatened by the accelerated mass loss which currently affects a large portion of so-called "benchmark" glaciers. In this work we present the evolution of the Careser glacier, from the beginning of systematic observation at the end of the nineteenth century to its current condition in 2012. In addition to having one of the longest and richest observation record among the Italian glaciers, Careser is unique in the Italian Alps for its 45 yr mass balance series started in 1967. In the present study, variations in the length, area and volume of the glacier since 1897 are examined, updating the series of direct mass balance observations and extending it into the past using the geodetic method. The glacier is currently strongly out of balance and in rapid decay; its average mass loss rate over the last three decades was −1.5 m water equivalent per year, increasing to −2.0 m water equivalent per year in the last decade. If mass loss continues at this pace, the glacier will disappear within a few decades, putting an end to this unique observation series.

scholarly journals Decay of a long-term monitored glacier: Careser Glacier (Ortles-Cevedale, European Alps)

2013 ◽  
Vol 7 (6) ◽  
pp. 1819-1838 ◽  
Author(s):  
L. Carturan ◽  
C. Baroni ◽  
M. Becker ◽  
A. Bellin ◽  
O. Cainelli ◽  
...  
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Mass Loss Rate ◽  
Regional Scale ◽  
European Alps ◽  
Systematic Observation ◽  
Average Mass ◽  
Observation Series ◽  
The 19Th Century

Abstract. The continuation of valuable, long-term glacier observation series is threatened by the accelerated mass loss which currently affects a large portion of so-called "benchmark" glaciers. In this work we present the evolution of the Careser Glacier, from the beginning of systematic observation at the end of the 19th century to its current condition in 2012. In addition to having one of the longest and richest observation records among the Italian glaciers, Careser is unique in the Italian Alps for its 46 yr mass balance series that started in 1967. In the present study, variations in the length, area and volume of the glacier since 1897 are examined, updating and validating the series of direct mass balance observations and adding to the mass balance record into the past using the geodetic method. The glacier is currently strongly out of balance and in rapid decay; its average mass loss rate over the last 3 decades was 1.5 m water equivalent per year, increasing to 2.0 m water equivalent per year in the last decade. Although these rates are not representative at a regional scale, year-to-year variations in mass balance show an unexpected increase in correlation with other glaciers in the Alps, during the last 3 decades. If mass loss continues at this pace, the glacier will disappear within a few decades, putting an end to this unique observation series.

scholarly journals Flammability and Thermal Kinetic Analysis of UiO-66-Based PMMA Polymer Composites

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4113
Author(s):  
Ruiqing Shen ◽  
Tian-Hao Yan ◽  
Rong Ma ◽  
Elizabeth Joseph ◽  
Yufeng Quan ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Mass Loss ◽  
Polymer Composites ◽  
Flame Retardants ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Protective Layer ◽  
Average Mass ◽  
Microscale Combustion Calorimeter ◽  
Combustion Calorimeter

Metal–organic frameworks (MOFs) are emerging as novel flame retardants for polymers, which, typically, can improve their thermal stability and flame retardancy. However, there is a lack of specific studies on the thermal decomposition kinetics of MOF-based polymer composites, although it is known that they are important for the modeling of flaming ignition, burning, and flame spread over them. The thermal decomposition mechanisms of poly (methyl methacrylate) (PMMA) have been well investigated, which makes PMMA an ideal polymer to evaluate how fillers affect its decomposition process and kinetics. Thus, in this study, UiO-66, a common type of MOF, was embedded into PMMA to form a composite. Based on the results from the microscale combustion calorimeter, the values of the apparent activation energy of PMMA/UiO-66 composites were calculated and compared against those of neat PMMA. Furthermore, under cone calorimeter tests, UiO-66, at only 1.5 wt%, can reduce the maximum burning intensity and average mass loss rate of PMMA by 14.3% and 12.4%, respectively. By combining UiO-66 and SiO2 to form a composite, it can contribute to forming a more compact protective layer, which shows a synergistic effect on reducing the maximum burning intensity and average mass loss rate of PMMA by 22.0% and 14.7%, respectively.

Retardant Properties of Nanosilica/PTFE Nanoparticals-Reinforced Polypropylene

2014 ◽  
Vol 1004-1005 ◽  
pp. 77-84 ◽  
Author(s):  
Zhen Lu Zhang ◽  
Dong Li Li ◽  
Wen Cai Xu ◽  
Ya Bo Fu ◽  
Rui Juan Liao
Keyword(s):  
Mass Loss ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Thermoplastic Polymer ◽  
Maximum Heat ◽  
Average Mass ◽  
Melting Characteristics

This work reports the flammability properties of Nanocomposites reinforced with silica and PTFE nanoparticles and toughened with an elastomeric ethylene-vinyl acetate (EVA). Through trial and simulation study of the flame retardant thermoplastic polymer and melting characteristics of PP in the combustion process.The study found that modified PP composites have good flame retardancy compared to PP in case of fire relatively.In the study,the melting characteristics of the thermoplastic polymer affected the mass loss rate in the combustion stage.Nanocomposites experienced low plastic mass loss compared with PP, this has been related to pyrolysis mechanism of polymer.In general,The polymers undergoing depolymerization will lead to a rapid volatilization and therefore experienced much less melting.The results showed that:total heat release of nanocomposites was higher than polypropylene, while the average heat release rate, the maximum heat release rate, the average effective heat of combustion, the average mass loss rate, the average specific extinction area, and other indicators were lower than polypropylene.

scholarly journals Link between Mass-loss and Variability Type for AGB Stars?

1999 ◽  
Vol 191 ◽  
pp. 395-400 ◽  
Author(s):  
Željko Ivezić ◽  
Gillian R. Knapp
Keyword(s):  
Mass Loss ◽  
Time Scales ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Dust Emission ◽  
Agb Stars ◽  
Similar Time ◽  
Color Distribution ◽  
K 12

We find that AGB stars separate in the 25–12 vs. 12-K color-color diagram according to their chemistry (O, S vs. C) and variability type (Miras vs. SRb/Lb). While discrimination according to the chemical composition is not surprising, the separation of Miras from SRb/Lb variables is unexpected.We show that “standard” steady-state radiatively driven models provide excellent fits to the color distribution of Miras of all chemical types. However, these models are incapable of explaining the dust emission from O-rich SRb/Lb stars. The models can be altered to fit the data by postulating different optical properties for silicate grains, or by assuming that the dust temperature at the inner envelope radius is significantly lower (300–400 K) than typical condensation temperatures (800–1000 K), a possibility which is also supported by the detailed characteristics of LRS data. While such lower temperatures are required only for O- and S-rich SRb/Lb stars, they are also consistent with the colors of C-rich SRb/Lb stars.The absence of hot dust for SRb/Lb stars can be interpreted as a recent (order of 100 yr) decrease in the mass-loss rate. The distribution of O-rich SRb/Lb stars in the 25–12 vs. K-12 color-color diagram shows that the mass-loss rate probably resumes again, on similar time scales. It cannot be ruled out that the mass-loss rate is changing periodically on such time scales, implying that the stars might oscillate between the Mira and SRb/Lb phases during their AGB evolution as proposed by Kerschbaum et al. (1996). Such a possibility appears to be supported by recent HST images of the Egg Nebula obtained by Sahai et al. (1997), the discovery of multiple CO winds reported by Knapp et al. (1998), and long-term visual light-curve changes detected for some stars by Mattei (1998).

scholarly journals Features of the kinetics of mass transfer processes in the process of firing ceramic materials

2018 ◽  
pp. 29-31
Author(s):  
O.M. Nedbailo ◽  
O.G. Chernyshyn
Keyword(s):  
Mass Transfer ◽  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Ceramic Materials ◽  
The Body ◽  
Mass Content ◽  
Transfer Coefficients ◽  
Average Mass ◽  
Firing Ceramic

In article the technique of definition factors of carrying over weight of substance in the course of roasting ceramic materials which is based on exponent dependences of change mass bodies from time of its heating is offered. The process of firing ceramic materials is associated with the transfer of heat and mass of matter. Therefore, for a more complete calculation of the heat treatment mode, it is necessary to know the conditions for the mass transfer in the product being calcined. The aim of the work is to determine the mass transfer coefficients of the substance in the process of firing ceramic materials. The mass loss rate of the bound matter or the mass loss per unit time will be directly proportional to the average mass content of the body. On the other hand, the mass loss rate of the bound matter is numerically equal to the slope of the mass content kinetics curve. Proposed in the work formulas can be applied when studying the process of mass transfer during firing of samples from different clays, as when firing clay samples of different diameters under the same conditions, they will differ in the mass content (mass loss rate of the bound substance) during heating and their final relative amount (mass content) of the lost mass will be the same.

scholarly journals On the evolutionary status and instability mechanism of the Luminous Blue Variables (LBV)

1989 ◽  
Vol 113 ◽  
pp. 15-26
Author(s):  
André Maeder
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Light Curves ◽  
Evolutionary Status ◽  
Average Mass ◽  
Luminous Blue Variables ◽  
Ir Sources ◽  
Order Of Magnitude ◽  
Lower Luminosity

AbstractVarious evolutionary sequences leading to LBV are examined. The sequence O-Of-LBV-WR-SN is well supported by the models; some LBV with relatively lower luminosity may turn into OH/IR sources. The overall duration of the LBV phase depends mainly on the average mass loss rate; for <Ṁ> = 10−3M⊙y−1, it lasts about 104y.Very massive stars undergo, when they reach logTeff= 3.9, strong departure from hydrostatic equilibrium due to supra-Eddington luminosities at some depth in the outer layers. This results in heavy mass loss, as the growth rate of the instability is very fast. We suggest that the amount of mass ejected in a shell episode is mainly determined by the mass of such a layer that its thermal adjustment timescale is within an order of magnitude of the stellar dynamical timescale. Simulations of B-light curves due to shell ejections by LBV are performed and some sensitive properties are identified.

scholarly journals The RCB Stars and their Circumstellar Material

1985 ◽  
Vol 87 ◽  
pp. 151-166
Author(s):  
M.W. Feast
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Circumstellar Dust ◽  
Average Mass ◽  
Circumstellar Material ◽  
Carbon Particles ◽  
Circumstellar Shell

RCB stars are surrounded by circumstellar dust and gas moving radially outwards at ~200 km/sec. The circumstellar shell is made up of discrete puffs of matter, a typical puff occupying an area ~0.03 of a complete shell. On the average puffs are ejected about once every 40 days (comparable with the known pulsation periods of RCB stars). The reddening law of the dust indicates that it is composed of small carbon particles (radii ~100A). The flux from the shell at L typically varies by 1 to 3 mags over periods of 1000-2000 days. The average mass loss rate is ~10−6MO/yr.

scholarly journals Mass balance in the Glacier Bay area of Alaska, USA, and British Columbia, Canada, 1995–2011, using airborne laser altimetry

2013 ◽  
Vol 59 (216) ◽  
pp. 632-648 ◽  
Author(s):  
Austin J. Johnson ◽  
Christopher F. Larsen ◽  
Nathaniel Murphy ◽  
Anthony A. Arendt ◽  
S. Lee Zirnheld
Keyword(s):  
British Columbia ◽  
Mass Loss ◽  
Mass Balance ◽  
Mass Loss Rate ◽  
Ice Age ◽  
Center Line ◽  
Laser Altimetry ◽  
Average Mass ◽  
Glacier Bay ◽  
Airborne Laser

AbstractThe Glacier Bay region of southeast Alaska, USA, and British Columbia, Canada, has undergone major glacier retreat since the Little Ice Age (LIA). We used airborne laser altimetry elevation data acquired between 1995 and 2011 to estimate the mass loss of the Glacier Bay region over four time periods (1995–2000, 2000–05, 2005–09, 2009–11). For each glacier, we extrapolated from center-line profiles to the entire glacier to estimate glacier-wide mass balance, and then averaged these results over the entire region using three difference methods (normalized elevation, area-weighted method and simple average). We found that there was large interannual variability of the mass loss since 1995 compared with the long-term (post-LIA) average. For the full period (1995–2011) the average mass loss was 3.93 ± 0.89 Gt a−1 (0.6 ± 0.1 m w.e. a−1), compared with 17.8 Gt a−1 for the post-LIA (1770–1948) rate. Our mass loss rate is consistent with GRACE gravity signal changes for the 2003–10 period. Our results also show that there is a lower bias due to center-line profiling than was previously found by a digital elevation model difference method.

scholarly journals The mass function and average mass-loss rate of dark matter subhaloes

2005 ◽  
Vol 359 (3) ◽  
pp. 1029-1040 ◽  
Author(s):  
Frank C. van den Bosch ◽  
Giuseppe Tormen ◽  
Carlo Giocoli
Keyword(s):  
Dark Matter ◽  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Mass Function ◽  
Average Mass

scholarly journals iPTF14hls as a variable hyper-wind from a very massive star

2019 ◽  
Author(s):  
Takashi J Moriya ◽  
Paolo A Mazzali ◽  
Elena Pian
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Variable Mass ◽  
Stellar Winds ◽  
Spectral Evolution ◽  
Extreme Wind ◽  
Sudden Outburst ◽  
Bright Phase

Abstract The origin of iPTF14hls, which had Type IIP supernova-like spectra but kept bright for almost two years with little spectral evolution, is still unclear. We here propose that iPTF14hls was not a sudden outburst like supernovae but rather a long-term outflow similar to stellar winds. The properties of iPTF14hls, which are at odds with a supernova scenario, become natural when interpreted as a stellar wind with variable mass-loss rate. Based on the wind hypothesis, we estimate the mass-loss rates of iPTF14hls in the bright phase. We find that the instantaneous mass-loss rate of iPTF14hls during the 2-year bright phase was more than a few M⊙ yr−1 (“hyper-wind”) and it reached as much as 10 M⊙ yr−1 . The total mass lost over two years was about 10 M⊙. Interestingly, we find that the light curve of iPTF14hls has a very similar shape to that of η Carinae during the Great Eruption, which also experienced a similar but less extreme brightening accompanied by extraordinary mass loss, shedding more than 10 M⊙ in 10 years. The progenitor of iPTF14hls is less than 150 M⊙ if it still exists, which is similar to η Carinae. The two phenomena may be related to a continuum-driven extreme wind from very massive stars.

Sign in / Sign up

Export Citation Format

Share Document