Avalanche is a common disaster occurring in the hilly regions. It is unsafe for the people residing and the adventure enthusiast that are present in such regions. Avalanche forecasting helps people ...to take any precautionary measures against high risk. It is extremely important to receive such vital information to communal in emergency condition. Present work proposes technological solution by providing software-based service and development of tool that would provide the avalanche occurrence information to the common man with the help of an android and windows application. This application predicts the probability of the avalanche occurrence condition at that instant to the users. It will also provide information about the past avalanche occurrences in the region. This research paper presents the outcome of research study on the data set for the Bahang region of Himachal Pradesh, India.
A wide optical-input dynamic range is demonstrated for an inverted p-down InAlAs/InGaAs avalanche photodiode. The 3 dB down bandwidth maintains a value as high as 18 GHz for an input optical power ...level of up to + 2.5 dBm. Such high-power tolerance meets the requirements of various future optical fibre communications systems such as 100 Gbit/s Ethernet which has a serial baud rate of 25 Gbit/s. PUBLICATION ABSTRACT
Utilizando un conjunto experimental especialmente diseñado, hemos estudiado la llamada transición de flujo continuo a intermitente en pilas de arena confinadas en una celda de Hele-Shaw donde la ...altura de deposición de la arena puede ser controlada además del flujo de alimentación. A través de mediciones sistemáticas que varían la altura y el flujo de entrada, hemos establecido cómo el tamaño de la pila al que tiene lugar la transición depende de los dos parámetros estudiados. Los resultados obtenidos permiten explicar, al menos semi-cuantitativamente, las observaciones comúnmente reportadas en la literatura, realizadas en experimentos donde la altura de deposición no fue controlada. Using a specially designed experimental set up, we have studied the so-called continuous to intermittent flow transition in sand piles confined in a Hele-Shaw cell where the deposition height of the sand can be controlled in addition to the input flow. Through systematic measurements varying the height and the input flow, we have established how the size of the pile at which the transition takes place depends on the two parameters studied. The results obtained allows to explain, at least semi-quantitatively, the observations commonly reported in the literature, carried out in experiments where the deposition height is not controlled. PACS: Hele-Shaw flows, 47.15.gp; Avalanches (granular systems), 45.70.Ht; Avalanches, phase transitions in, 64.60.av; Granular systems, classical mechanics of, 45.70.-n
Abstract The UIS characteristic of the device is a key parameter of the super-junction MOSFET, which represents the reliable performance of the device in the face of extreme conditions. The maximum ...avalanche energy ( E AS ) that the device can withstand under a single pulse of the gate electrode or the maximum avalanche energy ( E AR ) that the device can withstand under multiple pulses of the gate electrode is commonly used in the industry to characterize the UIS characteristic. To solve the avalanche energy problem of super-junction MOSFET, we propose a novel structure of super-junction MOSFET with a P-type diffused region on the top of the N-column drift region.
The structure of powder snow avalanches Sovilla, Betty; McElwaine, Jim N.; Louge, Michel Y.
Comptes rendus. Physique,
01/2015, Letnik:
16, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Powder snow avalanches (PSAs) can be hundreds of metres high and descend at astonishing speeds. This review paints a composite picture of PSAs from data acquired at the Vallée de la Sionne test site ...in Switzerland, including time-histories of snow cover thickness from buried Radar and, at several elevations on a pylon, impact pressures from load cells, air pressure, particle velocity from optical sensors, and cloud density and particle cluster size from capacitance probes. PSAs feature distinct flow regions with stratification in mean density. At the head, highly fluctuating impact pressures weaken with elevation, while vertical velocity profiles evolve rapidly along the flow, suggesting that surface snow layers of light, cold, cohesionless snow erupt into a turbulent, inhomogeneous, recirculating frontal cloud region. For hundreds of metres behind the head, cloud stratification sharpens with the deposition of suspended cloud particles, while a denser basal flow of increasing thickness forms as deeper, warmer and heavier parts of the weakened snow cover are entrained. Toward the tail, vertical velocity profiles are more uniform, impact pressures become lower and steadier as the flow becomes thinner, and snow pack entrainment is negligible.
Les avalanches en aérosol peuvent atteindre plusieurs centaines de mètres de hauteur et dévaler à des vitesses étonnantes. Cette revue peint une image générique de ces avalanches à partir de données obtenues sur le site de la vallée de la Sionne, en Suisse. Ces données incluent l'épaisseur du manteau neigeux en fonction du temps, observée par un radar enfoui et, à plusieurs hauteurs sur un pylône, des pressions d'impact provenant de cellules de charge, des mesures de pression de l'air, des vitesses de particules par l'intermédiaire de capteurs optiques et, enfin, la densité de l'aérosol et la taille de ses amas, par une sonde à capacité. Les avalanches en aérosol comprennent des zones distinctes, avec stratification de la densité moyenne. À leur front, les pressions d'impact fluctuent, mais s'affaiblissent avec la hauteur, alors que les profils verticaux de vitesse évoluent rapidement le long de l'écoulement. Ceci suggère que des couches de neige légère, froide et sans cohésion font éruption en créant une région frontale turbulente, hétérogène et recirculante. Sur des centaines de mètres derrière le front, la stratification de l'aérosol s'accroît avec la déposition de particules suspendues. Un écoulement de surface à épaisseur croissante s'établit alors, tandis que des éléments plus chauds et plus profonds du manteau neigeux sont entraînés. Vers la queue de l'avalanche, les profils verticaux s'uniformisent, la pression d'impact et ses fluctuations diminuent, alors que l'écoulement s'affine et que l'érosion du manteau neigeux devient négligeable.
The Tamins rock avalanche lies adjacent to the Flims rock avalanche, the largest in the Alps. Its deposit forms a ridge across the Rhine Valley just downstream of the confluence of the Vorderrhein ...and Hinterrhein rivers. The deposit is dominated by a 1.6-km-long longitudinal ridge, Ils Aults, and two roughly 600-m-long transverse ridges. Several extensional scarps bear witness to spreading of the deposit. A breach through the deposit, where the Rhine River presently flows, reveals a carapace and intense fragmentation. Exposure dating using cosmogenic
36
Cl yields an age of 9420 ± 880 years. This suggests that the Tamins event occurred in a time frame similar to the Flims event but was slightly earlier than the Flims rock avalanche, as also required by stratigraphic relationships. 3D volume modeling reveals bulking of only 14%. The motion of the rock avalanche seems to have occurred first as a flexible block, which underwent fragmentation and simple shearing where the top moved faster than the bottom. The ensuing spreading led to the formation of extensional scarps. There is no identified weak layer along the sliding surface; nevertheless, modeling suggests a friction angle of 10°.
In mountainous areas, channelized rock avalanches swarm downslope leading to large impact forces on building structures in residential areas. Arrays of rock avalanche baffles are usually installed in ...front of rigid barriers to attenuate the flow energy of rock avalanches. However, previous studies have not sufficiently addressed the mechanisms of interaction between the rock avalanches and baffles. In addition, empirical design approaches such as debris flow (Tang et al., Quat Int 250:63–73,
2012
), rockfall (Spang and Rautenstrauch, 1237–1243,
1988
), snow avalanches (Favier et al., 14:3–15,
2012
), and rock avalanches (Manzella and Labiouse, Landslides 10:23–36,
2013
), which are applied in natural geo-disasters mitigation cannot met construction requirements. This study presents details of numerical modeling using the discrete element method (DEM) to investigate the effect of the configuration of baffles (number and spacing of baffle columns and rows) on the impact force that rock avalanches exert on baffles. The numerical modeling is firstly conducted to provide insights into the flow interaction between rock avalanches and an array of baffles. Then, a modeling analysis is made to investigate the change pattern of the impact force with respect to baffle configurations. The results demonstrate that three crucial influencing factors (baffle row numbers, baffle column spacing, and baffle row spacing) have close relationship with energy dissipation of baffles. Interestingly, it is found that capacity of energy dissipation of baffles increases with increasing baffle row numbers and baffle row spacing, while it decreases with increasing baffle column spacing. The results obtained from this study are useful for facilitating design of baffles against rock avalanches.
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