scholarly journals Ski piste snow ablation versus potential infiltration (Veporic Unit, Western Carpathians)

2020 ◽  
Vol 68 (1) ◽  
pp. 28-37 ◽  
Author(s):  
Michal Mikloš ◽  
Dušan Igaz ◽  
Karol Šinka ◽  
Jana Škvareninová ◽  
Martin Jančo ◽  
...  
Keyword(s):  
Snow Water Equivalent ◽  
Water Movement ◽  
Average Rate ◽  
High Volume ◽  
Ablation Rate ◽  
Frozen Soil ◽  
Western Carpathians ◽  
Water Volume ◽  
South Central ◽  
Natural Snow

AbstractSnow production results in high volume of snow that is remaining on the low-elevation ski pistes after snowmelt of natural snow on the off-piste sites. The aim of this study was to identify snow/ice depth, snow density, and snow water equivalent of remaining ski piste snowpack to calculate and to compare snow ablation water volume with potential infiltration on the ski piste area at South-Central Slovak ski center Košútka (Inner Western Carpathians; temperate zone). Snow ablation water volume was calculated from manual snow depth and density measurements, which were performed at the end of five winter seasons 2010–2011 to 2015–2016, except for season 2013–2014. The laser diffraction analyzes were carried out to identify soil grain size and subsequently the hydraulic conductivity of soil to calculate the infiltration. The average rate of water movement through soil was seven times as high as five seasons’ average ablation rate of ski piste snowpack; nevertheless, the ski piste area was potentially able to infiltrate only 47% of snow ablation water volume on average. Limitation for infiltration was frozen soil and ice layers below the ski piste snowpack and low snow-free area at the beginning of the studied ablation period.

scholarly journals Numerical Simulation of Thawing Process in Frozen Soil

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Zhaoyu Yan ◽  
Wei Pan ◽  
Junjie Fang ◽  
Zihui Liu
Keyword(s):  
Numerical Simulation ◽  
Heat Flux ◽  
Liquid Water ◽  
Minimum Temperature ◽  
Frozen Soil ◽  
Total Heat ◽  
Water Volume ◽  
Total Heat Flux ◽  
Volume Curve ◽  
Thawing Process

Permafrost has been thawing faster due to climate change which would release greenhouse gases, change the hydrological regimes, affect buildings above, and so on. It is necessary to study the thawing process of frozen soil. A water-heat coupling model for frozen soil thawing is established on Darcy’s law and Heat Transfer in Porous Media interfaces in Comsol Multiphysics 5.5. Three curves of total liquid water volume, minimum temperature, and total heat flux in the thawing process are obtained from a numerical simulation. The distributions of liquid water, temperature, and pressure based on time are simulated too. The liquid water distribution is consistent with the total liquid water volume curve. The temperature distribution is confirmed by the minimum temperature and total heat flux curve. The pressure distribution represents ice in the frozen soil that generates negative pressure during the melting process. The numerical simulation research in this article deepens the understanding of the internal evolution in the process of frozen soil thawing and has a certain reference value for subsequent experimental research and related applications.

scholarly journals Serological prevalence of six vector-borne pathogens in dogs presented for elective ovariohysterectomy or castration in the South central region of Texas

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
J. Mack Fudge ◽  
Bailey Boyanowski ◽  
Bernie Page ◽  
Shuling Liu ◽  
Artem S. Rogovskyy
Keyword(s):  
Central Region ◽  
High Volume ◽  
Geographic Region ◽  
Seroprevalence Rate ◽  
The South ◽  
Vector Borne Diseases ◽  
Disease Epidemiology ◽  
South Central ◽  
Test Kit ◽  
Vector Borne

Abstract Background Most vector-borne pathogens cause zoonotic diseases. These zoonoses often have wild animal reservoirs that play a significant role in disease epidemiology. However, pet animals have also been implicated in transmission of zoonotic agents to humans. To exemplify, dogs are competent reservoir hosts for several zoonotic vector-borne bacteria and protozoa. Despite that vector-borne diseases can be life-threatening for both pets and humans, studies on pathogen seroprevalence are very limited. Therefore, the objective of this study was to determine the serological prevalence of six zoonotic vector-borne agents in dogs from the South Central region of Texas (US). Electronic medical records of dogs, presenting over 2014–2019 for elective ovariohysterectomy or castration at a high volume spay and neuter clinic, were reviewed for serological testing. Sera from 418 dogs were tested for the Dirofilaria immitis antigen, and antibodies to Anaplasma phagocytophilum, Anaplasma platys, Borrelia burgdorferi, Ehrlichia canis, and Ehrlichia ewingi, using a commonly available commercial test kit. Descriptive statistics were computed to characterize the respective seroprevalence rates of the dog population. The study involved 192 (46%) male and 226 (54%) female dogs. Results Overall, 85 (20%) dogs tested positive for at least one of the 6 pathogens investigated. The highest seroprevalence rate averaged over the 6-year period was 11.7% for D. immitis followed by 8.4% for E. canis and/or E. ewingii, 4.3% for A. phagocytophilum and/or A. platys, and 0.2% for B. burgdorferi. The co-exposure or co-infection was only detected in 3.8% of the dog population. Conclusions Together, opportunistic testing of dogs presenting for elective surgical procedures may provide an effective way of assessing seroprevalence and/or risk factors for common vector-borne diseases within a geographic region of concern.

Effect of Water Volume on the Growth of Silver Nanoparticles Promoted by Ultraviolet

2010 ◽  
Vol 96 ◽  
pp. 55-59 ◽  
Author(s):  
Jing Chen ◽  
Ye Ling Jin
Keyword(s):  
Silver Nanoparticles ◽  
Blue Shift ◽  
High Volume ◽  
High Water ◽  
Water Volume ◽  
Reactive System ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
On Line ◽  
Low Volume

The formation process of silver nanoparticles promoted by ultraviolet has been investigated by on-line UV-vis spectroscopy and transmission electron microscope (TEM). We firstly report that the volume of water will result in the growth of silver nanoparticles with different mechanism, UV-vis spectra show that the growth of nanopaticles presents blue-shift for reactive system with high volume water, but red-shift for that of low volume water. Moreover, experiments reveal that high water volume results in the change of the color of the silver sol accordingly.

scholarly journals Utility of late summer transient snowline migration rate on Taku Glacier, Alaska

2011 ◽  
Vol 5 (4) ◽  
pp. 1127-1133 ◽  
Author(s):  
M. Pelto
Keyword(s):  
Mass Balance ◽  
Migration Rate ◽  
Satellite Images ◽  
Snow Water Equivalent ◽  
Late Summer ◽  
Ablation Rate ◽  
Field Observations ◽  
Balance Assessment ◽  
Snow Water ◽  
The Mean

Abstract. On Taku Glacier, Alaska a combination of field observations of snow water equivalent (SWE) from snowpits and probing in the vicinity of the transient snowline (TSL) are used to quantify the mass balance gradient. The balance gradient derived from the TSL and SWE measured in snowpits at 1000 m from 1998–2010 ranges from 2.6–3.8 mm m−1. Probing transects from 950 m–1100 m directly measure SWE and yield a slightly higher balance gradient of 3.3–3.8 mm m−1. The TSL on Taku Glacier is identified in MODIS and Landsat 4 and 7 Thematic Mapper images for 31 dates during the 2004–2010 period to assess the consistency of its rate of rise and reliability in assessing ablation for mass balance assessment. For example, in 2010, the TSL was 750 m on 28 July, 800 m on 5 August, 875 m on 14 August, 925 m on 30 August, and 975 m on 20 September. The mean observed probing balance gradient was 3.3 mm m−1, combined with the TSL rise of 3.7 m day−1 yields an ablation rate of 12.2 mm day−1 from mid-July to mid-Sept, 2010. The TSL rise in the region from 750–1100 m on Taku Glacier during eleven periods each covering more than 14 days during the ablation season indicates a mean TSL rise of 3.7 m day−1, the rate of rise is relatively consistent ranging from 3.1 to 4.4 m day−1. This rate is useful for ascertaining the final ELA if images or observations are not available near the end of the ablation season. The mean ablation from 750–1100 m during the July–September period determined from the TSL rise and the observed balance gradient is 11–13 mm day−1 on Taku Glacier during the 2004–2010 period. The potential for providing an estimate of bn from TSL observations late in the melt season from satellite images combined with the frequent availability of such images provides a means for efficient mass balance assessment in many years and on many glaciers.

scholarly journals Spatial and temporal variability of snow depth and SWE in a small mountain catchment

2010 ◽  
Vol 4 (1) ◽  
pp. 1-30 ◽  
Author(s):  
T. Grünewald ◽  
M. Schirmer ◽  
R. Mott ◽  
M. Lehning
Keyword(s):  
Temporal Variability ◽  
Snow Depth ◽  
Energy Transport ◽  
Snow Water Equivalent ◽  
Laser Scanner ◽  
Ablation Rate ◽  
Spatial And Temporal Variability ◽  
M Cell ◽  
Snow Water ◽  
Spatio Temporal

Abstract. The spatio-temporal variability of the mountain snow cover determines the avalanche danger, snow water storage, permafrost distribution and the local distribution of fauna and flora. Using a new type of terrestrial laser scanner (TLS), which is particularly suited for measurements of snow covered surfaces, snow depth, snow water equivalent (SWE) and melt rates have been monitored in a high alpine catchment during an ablation period. This allowed for the first time to get a high resolution (2.5 m cell size) picture of spatial variability and its temporal development. A very high variability in which maximum snow depths between 0–9 m at the end of the accumulation season was found. This variability decreased during the ablation phase, although the dominant snow deposition features remained intact. The spatial patterns of calculated SWE were found to be similar to snow depth. Average daily melt rate was between 15 mm/d at the beginning of the ablation period and 30 mm/d at the end. The spatial variation of melt rates increased during the ablation rate and could not be explained in a simple manner by geographical or meteorological parameters, which suggests significant lateral energy fluxes contributing to observed melt. It could be qualitatively shown that the effect of the lateral energy transport must increase as the fraction of snow free surfaces increases during the ablation period.

Ash on Snow a Tool – A Tool to Prevent Flooding?

2001 ◽  
Vol 32 (3) ◽  
pp. 195-214 ◽  
Author(s):  
Angela Lundberg ◽  
H Beyerl
Keyword(s):  
Snow Water Equivalent ◽  
Short Wave ◽  
Wood Ash ◽  
Wave Radiation ◽  
Short Wave Radiation ◽  
Index Method ◽  
Temperature Index ◽  
Index Model ◽  
Snow Water ◽  
Natural Snow

Years with late spring in combination with thick snow-pack constitute risk for flooding. To decrease that risk, the possibility of spreading albedo-lowering material (wood ash) on parts of a basin snow has been examined. By blackening the snow more solar radiation is absorbed and the snowmelt is enhanced. If sun-exposed parts of the basin are ash-treated (before normal runoff starts) the runoff will be distributed over a longer period of time and the risk of flooding will be reduced. Wood ash in different concentrations was spread on small snow plots and melt rates and albedo were measured. For snow covered with 0.03 kg ash m−2, the albedo was decreased from ≈ 0.60 for natural snow to ≈ 0.25, resulting in ≈ 90% more absorbed short-wave radiation. Melt on the ash treated surface, (daily average snow water equivalent), was 70% larger than melt on natural snow (12 and 7 mm d−1 respectively). A five times larger concentration (0.15 kg m−2) only increased the melt rate to 14 mm d−1. The temperature-index method was shown to be inadequate for modelling the melt rate for the ash treated snow. A radiation-index model, based on absorbed incoming short wave radiation, was shown to model the melt rate better than the temperature-index method.

Abstract T MP96: Trends and Variation in Inpatient Discharge to Hospice Among High Stroke Volume Hospitals

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Benjamin P George ◽  
Adam G Kelly ◽  
Eric B Schneider ◽  
Robert G Holloway
Keyword(s):  
Ischemic Stroke ◽  
Stroke Volume ◽  
Acute Ischemic Stroke ◽  
Hospice Care ◽  
Average Rate ◽  
High Volume ◽  
Absolute Number ◽  
Annual Growth Rate ◽  
Compound Annual Growth Rate ◽  
Hospital Variation

Background: In recent years, individuals with acute ischemic stroke accounted for approximately 4% of all inpatients discharged to hospice, yet little is known about current practices and trends in discharge to hospice care for stroke admissions within US hospitals. Methods: We examined rates of hospice discharge for adult acute ischemic stroke patients admitted to acute care facilities in the top quartile of annual stroke volume between 2001 and 2010 in the Nationwide Inpatient Sample. These high volume hospitals account for nearly 75% of stroke admissions in the dataset. Only those with available information on hospice discharge were considered. Compound annual growth rate was used to examine changes in utilization over time. Hospice trends were evaluated using the Cochran-Armitage test. Results: Among 1,935 high volume hospitals there were 455,372 hospitalizations for acute ischemic stroke from 2001 to 2010, 12,036 (2.6%) of which were discharged to hospice (30% to home; 70% to medical facility). The absolute number of discharges to hospice care grew at 29% per year over the ten-year period (P Trend<0.001). Discharge rates to hospice care per 100 stroke admissions increased from an average of 0.5 (SD=1.3) in 2001 to 4.3 (SD=3.0) in 2010 (P Trend<0.001). Inter-hospital variation in rates of hospice discharge remained large from year to year, and ranged from zero to 15.6 per 100 stroke admissions (Median=3.8; Interquartile Range=3.7) in 2010. Conclusions: The average rate of discharge to hospice care for acute ischemic stroke inpatients admitted to high volume hospitals has grown substantially in the past decade; variation in this practice across these hospitals remains large.

scholarly journals Spatial and temporal variability of snow depth and ablation rates in a small mountain catchment

2010 ◽  
Vol 4 (2) ◽  
pp. 215-225 ◽  
Author(s):  
T. Grünewald ◽  
M. Schirmer ◽  
R. Mott ◽  
M. Lehning
Keyword(s):  
Snow Cover ◽  
Temporal Variability ◽  
Snow Depth ◽  
Energy Transport ◽  
Snow Water Equivalent ◽  
Laser Scanner ◽  
Ablation Rate ◽  
Spatial And Temporal Variability ◽  
M Cell ◽  
Snow Water

Abstract. The spatio-temporal variability of the mountain snow cover determines the avalanche danger, snow water storage, permafrost distribution and the local distribution of fauna and flora. Using a new type of terrestrial laser scanner, which is particularly suited for measurements of snow covered surfaces, snow depth was monitored in a high alpine catchment during an ablation period. From these measurements snow water equivalents and ablation rates were calculated. This allowed us for the first time to obtain a high resolution (2.5 m cell size) picture of spatial variability of the snow cover and its temporal development. A very high variability of the snow cover with snow depths between 0–9 m at the end of the accumulation season was observed. This variability decreased during the ablation phase, while the dominant snow deposition features remained intact. The average daily ablation rate was between 15 mm/d snow water equivalent at the beginning of the ablation period and 30 mm/d at the end. The spatial variation of ablation rates increased during the ablation season and could not be explained in a simple manner by geographical or meteorological parameters, which suggests significant lateral energy fluxes contributing to observed melt. It is qualitatively shown that the effect of the lateral energy transport must increase as the fraction of snow free surfaces increases during the ablation period.

Reducing Set Retardation in High-Volume Fly Ash Mixtures with the Use of Limestone

2012 ◽  
Vol 2290 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Lisa R. Gurney ◽  
Dale P. Bentz ◽  
Taijiro Sato ◽  
W. Jason Weiss
Keyword(s):  
Fly Ash ◽  
Volume Fraction ◽  
High Volume ◽  
Reaction Rates ◽  
Limestone Powder ◽  
Water Volume ◽  
Early Age ◽  
Ternary Blends ◽  
Setting Times ◽  
High Volume Fly Ash

High-volume fly ash (HVFA) concretes are attractive not only because they reduce cement content and the associated greenhouse gases, but also because they avoid landfilling excessive quantities of fly ash. These sustainability benefits are often tempered by practical constructability limitations that may exist for HVFA concretes: retardation and diminution of the early-age reaction, delay in setting (and finishing operations), and lower early-age strength. This paper explores the alleviation of these deficiencies in HVFA mixtures by the incorporation of fine limestone powders into ternary blends. Isothermal calorimetry and Vicat needle penetration measurements are employed to assess reaction rates and setting times, respectively. A systematic variation of the content and fineness of the limestone powder in mixtures containing either a Class C or a Class F fly ash indicates that setting times are linearly correlated with the surface area supplied by the limestone. Comparison of a limestone system to a system containing an inert titanium dioxide of similar particle size indicates that the acceleration and amplification effects of the limestone can be attributed to both physical (nucleation) and chemical (additional calcium ions) processes. The results indicate that ternary blends with 40% of the cement by volume replaced by 30% to 35% fly ash and 5% to 10% limestone at a constant water volume fraction can be achieved without significant delay in setting.

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