scholarly journals Change in snow strength caused by rain

2012 ◽  
Vol 53 (61) ◽  
pp. 1-5 ◽  
Author(s):  
Yoichi Ito ◽  
Hiroki Matsushita ◽  
Hiroyuki Hirashima ◽  
Yasuhiko Ito ◽  
Tomoyuki Noro
Keyword(s):  
Water Content ◽  
Laboratory Experiments ◽  
Empirical Relationship ◽  
High Water ◽  
High Water Content ◽  
Snow Avalanches ◽  
Wetting Front ◽  
Snow Condition ◽  
Wet Snow ◽  
Before And After

AbstractRain-on-snow events can cause wet snow avalanches. Laboratory experiments were carried out to investigate the change in snow strength with increasing water content through rainwater percolation. Snowpack was artificially prepared consisting of a thin ice layer and fine compacted snow, and rainfall (2mmh–1) was artificially applied 22–25.5 and 49–52 hours after the snowpack was formed. Snow hardness was measured with a push–pull force gauge to indicate the snow strength before and after each rain-on-snow event. After the first rainfall, the upper half of the snowpack became wet and a rapid decrease in snow hardness was observed. After the second rainfall the rainwater penetrated the ice layer, high water content was observed above the ice layer but the hardness exceeded that estimated from an empirical relationship between hardness and water content. Micrographs of the snow particles suggest that the delay in grain coarsening observed near the wetting front induces the harder than estimated snow condition.

scholarly journals Wet-snow avalanche interaction with a deflecting dam: field observations and numerical simulations in a case study

2012 ◽  
Vol 12 (5) ◽  
pp. 1407-1423 ◽  
Author(s):  
B. Sovilla ◽  
I. Sonatore ◽  
Y. Bühler ◽  
S. Margreth
Keyword(s):  
Numerical Simulations ◽  
Water Content ◽  
High Water ◽  
Residual Risk ◽  
Snow Avalanche ◽  
High Water Content ◽  
Small Scale ◽  
Snow Avalanches ◽  
Complex Flow ◽  
Wet Snow

Abstract. In avalanche-prone areas, deflecting dams are widely used to divert avalanches away from endangered objects. In recent years, their effectiveness has been questioned when several large and multiple avalanches have overrun such dams. In 2008, we were able to observe a large wet-snow avalanche, characterized by an high water content, that interacted with a deflecting dam and overflowed it at its lower end. To evaluate the dam's performance, we carried out an airborne laser scanning campaign immediately after the avalanche. This data, together with a video sequence made during the avalanche descent, provided a unique data set to study the dynamics of a wet dense snow avalanche and its flow behavior along a deflecting dam. To evaluate the effect of the complex flow field of the avalanche along the dam and to provide a basis for discussion of the residual risk, we performed numerical simulations using a two-dimensional dense snow avalanche dynamics model with entrainment. In comparison to dry dense snow avalanches, we found that wet-snow avalanches, with high water content, seem to be differently influenced by the local small-scale topography roughness. Rough terrain close to the dam deflected the flow to produce abrupt impacts with the dam. At the impact sites, instability waves were generated and increased the already large flow depths. The complex flow dynamics around the dam may produce large, local snow deposits. Furthermore, the high water content in the snow may decrease the avalanche internal friction angle, inducing wet-snow avalanches to spread further laterally than dry-snow avalanches. Based on our analysis, we made recommendations for designing deflecting dams and for residual risk analysis to take into account the effects of wet-snow avalanche flow.

scholarly journals Pemanfaatan Ekstrak Daun Mahkota Dewa (Phaleria macrocarpa (Scheff.) Boerl) sebagai Pengawet Tomat

2017 ◽  
Vol 5 (2) ◽  
pp. 67 ◽  
Author(s):  
Dina Supriatni ◽  
Irwan Said ◽  
Siang Tandi Gonggo
Keyword(s):  
Vitamin C ◽  
Water Content ◽  
Leaf Extract ◽  
Tomato Fruit ◽  
High Water ◽  
High Water Content ◽  
Iodometric Titration ◽  
Before And After ◽  
Phaleria Macrocarpa

Tomato fruit is one of the fruits susceptible to decay because of its high water content. The durability of tomato can be improved by storing in a humid place or by adding of a preservative. Phaleriamacrocarpa (Scheff.) boerlleaf can act as an antibacterial due to the saponin compounds contained therein. This study aimed to investigate the phaleriamacrocarpa (Scheff.) boerlleaf extract as a preservative for tomatoes, and to determine the concentration of leaf extract to sustain tomatoes texture longer. The method used in this study was the maceration for extraction, and iodometric titration to determine of vitamin C levels before and after curing. The results showed that the pickling tomatoes using phaleriamacrocarpa (Scheff.) boerl leaf extract with a concentration of 6% sustained tomatoes up to 9 days, and the fruit decreased levels of vitamin C from 33.440 mg/100 g material into 27.580 mg/100 g of material.

scholarly journals Wet-snow instabilities: comparison of measured and modelled liquid water content and snow stratigraphy

2011 ◽  
Vol 52 (58) ◽  
pp. 201-208 ◽  
Author(s):  
Christoph Mitterer ◽  
Hiroyuki Hirashima ◽  
Jürg Schweizer
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Water Flux ◽  
Liquid Water Content ◽  
Vital Role ◽  
Snow Avalanches ◽  
Wetting Front ◽  
Snow Stratigraphy ◽  
Capillary Barriers ◽  
Wet Snow

AbstarctWet-snow avalanches are difficult to forecast, as the change from stable to unstable snow conditions occurs rapidly in a wet snowpack, often in response to water production and movement. Snow stratigraphy plays a vital role in determining flux behaviour. Capillary barriers or melt–freeze crusts can impede and divert water horizontally over large areas and thus may act as a failure layer for wet-snow avalanches. We present a comparison of measured and modelled liquid water content, θw, and snow stratigraphy during periods of wet-snow instabilities. Special attention is given to the reproducibility of capillary barriers, ponding of water on melt–freeze crusts and the timing of first wetting and of water arrival at the bottom of the snowpack, because these factors are believed to play a major role in the formation of wet-snow avalanches. In situ measurements were performed in the vicinity of automatic weather stations or close to recent wet-snow avalanches in order to compare them with model results. The simulations are based on two different water flux models incorporated within the 1-D snow-cover model SNOWPACK. The comparison of the two model runs with observed θw and stratigraphy revealed that both water-transport models reproduced the ponding of water on melt–freeze crusts. However, in both models melt–freeze crusts were transformed to normal melt forms earlier than observed in nature, so still existing ponding was not captured by the models. Only one of the models was able to reproduce capillary barriers in agreement with observations. The time of the first wetting at the surface was well predicted, but the simulated arrival time of the wetting front at the bottom of the snowpack differed between the simulations; it was either too early or too late compared with the observation.

scholarly journals Uji Efektivitas Ekstrak Buah Bengkuang (Pachyrhizus erosus (L.) Urb.) Sebagai Pengawet Alami Cabai Merah (Capsicum annuum L)

2017 ◽  
Vol 5 (3) ◽  
pp. 109
Author(s):  
Citra Larasari ◽  
Baharuddin Hamzah ◽  
Suherman Suherman
Keyword(s):  
Vitamin C ◽  
Water Content ◽  
Capsicum Annuum ◽  
High Water ◽  
Effective Concentration ◽  
High Water Content ◽  
Natural Preservative ◽  
Capsicum Annuum L ◽  
Pachyrhizus Erosus ◽  
Before And After

Red chili is one of the food susceptible to decay. It caused by its high water content and so it causes to keep power of red chili abbreviated. Jicama (pachyrizuserosus (L.) Urb.) can act as a natural preservative for red chili due to the saponin compounds contained there in. This study aimed to prove the use of jicama extract as a natural preservative for red chili and to determine the most effective concentration of jicama extract as a natural preservative. The methods used in this study were a maceration to prepare the extract of jicama, and an iodimetric titration to determine the levels of vitamin C before and after curing. The results showed that jicama extract can be used as a natural preservative for red chili. The most effective concentration of jicama extract in preserving the red chili was 4% with preservation durability of red chili for 14 days in which the smallest level of vitamin C decreased among other concentrations, i.e. from 84.47 mg/100 g to 75.13 mg/100 g of material.

scholarly journals Desiccation of Pachira aquatica Aubl. Seeds

2018 ◽  
Vol 10 (11) ◽  
pp. 553
Author(s):  
Amanda Araújo Lima ◽  
Edilma Pereira Gonçalves ◽  
Jeandson Silva Viana ◽  
Priscila Cordeiro Souto ◽  
Débora Teresa da Rocha Gomes Ferreira ◽  
...  
Keyword(s):  
Water Content ◽  
Native Species ◽  
Seed Quality ◽  
Germination Rate ◽  
High Water ◽  
High Water Content ◽  
Small Reduction ◽  
Drying Temperature ◽  
Before And After ◽  
Physiological Quality

The conservation of seed quality during storage is important to perform the maintenance and conservation of germplasm banks. Several native species of Brazil are intolerant to desiccation to desirable levels for conservation during storage is necessary to develop specific technologies for their conservation. The objective of this research was to evaluate the physiological quality of Paquira aquatica seeds submitted to drying periods. The study was carried out using seeds of P. aquatica dried at a temperature of 35 ºC, the following exposure times: 0 (no drying), 24, 48, 72 and 96 hours. Before and after each period of drying samples for the evaluations, the data were submitted to analysis of variance and regressionat level of 5%. The seeds of P. aquatica were dispersed with very high water content and a small reduction in its physiological value agrees quality, allowing the seeds to characterize this as a recalcitrant species. The drying temperature is 35 ºC until the viable 24 hours after this period the water content of seed reduced from 55% to 43%, which was considered the critical level for desiccation of seeds of P. aquatica. Because it reduces the values of first count, germination, rate of germination and growth of seedlings.The drying temperature the 35 ºC until the viable 24 hours, whit small reduction in its physiological quality seed P. aquatica.

Hydrogels as Antibacterial Biomaterials

2018 ◽  
Vol 24 (8) ◽  
pp. 843-854 ◽  
Author(s):  
Weiguo Xu ◽  
Shujun Dong ◽  
Yuping Han ◽  
Shuqiang Li ◽  
Yang Liu
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Tissue Engineering ◽  
Water Content ◽  
Oxygen Permeability ◽  
Structural Diversity ◽  
High Water ◽  
Clinical Applications ◽  
High Water Content ◽  
Biomedical Field

Hydrogels, as a class of materials for tissue engineering and drug delivery, have high water content and solid-like mechanical properties. Currently, hydrogels with an antibacterial function are a research hotspot in biomedical field. Many advanced antibacterial hydrogels have been developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs and structural diversity. In this article, an overview is provided on the preparation and applications of various antibacterial hydrogels. Furthermore, the prospects in biomedical researches and clinical applications are predicted.

Microwave-Induced Thermoacoustic Imaging for Embedded Explosives Detection in High-Water Content Medium

2019 ◽  
Vol 67 (7) ◽  
pp. 4803-4810 ◽  
Author(s):  
Xiong Wang ◽  
Tao Qin ◽  
Yexian Qin ◽  
Ahmed H. Abdelrahman ◽  
Russell S. Witte ◽  
...  
Keyword(s):  
Water Content ◽  
High Water ◽  
Explosives Detection ◽  
High Water Content ◽  
Thermoacoustic Imaging

scholarly journals Deep mantle melting, global water circulation and its implications for the stability of the ocean mass

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Shun-ichiro Karato ◽  
Bijaya Karki ◽  
Jeffrey Park
Keyword(s):  
Phase Transformation ◽  
Water Content ◽  
Sea Level ◽  
High Water ◽  
Water Circulation ◽  
Mantle Melting ◽  
High Water Content ◽  
Mineral Physics ◽  
Deep Mantle ◽  
Global Water

AbstractOceans on Earth are present as a result of dynamic equilibrium between degassing and regassing through the interaction with Earth’s interior. We review mineral physics, geophysical, and geochemical studies related to the global water circulation and conclude that the water content has a peak in the mantle transition zone (MTZ) with a value of 0.1–1 wt% (with large regional variations). When water-rich MTZ materials are transported out of the MTZ, partial melting occurs. Vertical direction of melt migration is determined by the density contrast between the melts and coexisting minerals. Because a density change associated with a phase transformation occurs sharply for a solid but more gradually for a melt, melts formed above the phase transformation depth are generally heavier than solids, whereas melts formed below the transformation depth are lighter than solids. Consequently, hydrous melts formed either above or below the MTZ return to the MTZ, maintaining its high water content. However, the MTZ water content cannot increase without limit. The melt-solid density contrast above the 410 km depends on the temperature. In cooler regions, melting will occur only in the presence of very water-rich materials. Melts produced in these regions have high water content and hence can be buoyant above the 410 km, removing water from the MTZ. Consequently, cooler regions of melting act as a water valve to maintain the water content of the MTZ near its threshold level (~ 0.1–1.0 wt%). Mass-balance considerations explain the observed near-constant sea-level despite large fluctuations over Earth history. Observations suggesting deep-mantle melting are reviewed including the presence of low-velocity anomalies just above and below the MTZ and geochemical evidence for hydrous melts formed in the MTZ. However, the interpretation of long-term sea-level change and the role of deep mantle melting in the global water circulation are non-unique and alternative models are reviewed. Possible future directions of studies on the global water circulation are proposed including geodynamic modeling, mineral physics and observational studies, and studies integrating results from different disciplines.

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