steep slopes
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Author(s):  
Fares M. Howari ◽  
Manish Sharma ◽  
Cijo M. Xavier ◽  
Yousef Nazzal ◽  
Fatima Alaydaroos

Recurring slope lineae (RSL) are small, dark, seasonal albedo features lengthening down “warm” Martian steep slopes. Their origin has been attributed to both liquid and dry processes, hence representing one of the major open science questions on present day Mars. In the present study, we report a catalog of previous literature and newly added RSL sites making a total of 940 sites globally on Mars along with the detailed geological and compositional investigation of the Hale and Asimov craters with their RSL features. We also estimate temperature and atmospheric water abundances in the study area, which are two of the main factors to explain the origin and formation of RSL. The study found that the Asimov crater’s local temperatures are high enough to allow either the melting of brines or deliquescence of calcium perchlorate and other salts during the HiRISE observation period and found the water vapor column to be nearly five times higher than those measured “before RSL appearance.” This supports the theory of deliquescence as one of the mechanisms for the regolith-atmosphere interaction and RSL formation in the studied crater, which suggests that minerals absorb moisture from the environment until the minerals dissolve in the absorbed water and yield a solution. We also used compact reconnaissance imaging spectrometer for Mars–derived browse products for a compositional study associated with RSL features hosting craters and surface characteristics of Mars.


2022 ◽  
Author(s):  
heller frederic

Summary:The Neolithic site of the Bosquet del Vau is located in the Brabant Province in Belgium. Two different rescue excavations took place on the site both in 2006 and 2007 : the first was subsequent to a housing project of about 110 houses, the latter to the building of the R.E.R. (Express Regional Transportation System).The site was discovered in the 1980 by a group of three teenagers going flint tools hunting all around Waterloo and Braine l’Alleud. Flint tools pertaining to the Late Neolithic and Early Bronze Age were recovered on site as well as some Mesolithic flint tools.The site is located on a small sandy hill and covers 2.5 hectares. Steep slopes surround it to the west and north-west and gentler ones to the northeast and south, an isthmus exists to the east linking it o the plateau.The settlement is protected by a palisade to the east and south, a wide ditch links the palisade to the nearly valley to the west. The western side of the hill has seen its slope artificially steepened as did part of the northern side. No palisade was found on either of those two sides.Part of one house and a complete second one were discovered in 2006 and 2007. They are aligned north to south, 18 meters long and 4.5 meters wide. A narrow ditch houses the post holes, posts are maximum 0.30 m in diameter and spaced evenly. Central posts suggest a two-sloped roof. No hearth was found inside of the first house, the one of the second has yet to be associated with the house.A phosphate map was made in both cases, evidence points to a house divided into three parts, with maybe a cattle area next to the second one.Potsherds recovered in two postholes of the 2007 house fit together and could be dated to the Late Neolithic Period.Flint tools are mostly micro-denticulates though a few polished axes fragments have been discovered as well as arrowheads and a beautifully knapped flint knife.The various types of stones used: from black flintstone to Parisian flintstone and phtanite suggest here again a Late-Neolithic dating.


This research emphasizes the cause of landslides that occur in Hakha Town and its environ. The main aim is to investigate the distinct phenomena that result in a landslide and to provide suggestions that can reduce the risk of landslide in its prone area. Regarding the two phenomena, natural and man-made, the data on soil, steep slope, monsoon rainfall, pine forest areas, water sources, motor-car road area, population, and houses were collected by field survey, observation, and questionnaires. The collected data were processed and analyzed by using remote sensing methods, qualitative and quantitative methods, and Geographic Information System. According to the results, major causes of the landslides in the study area are found to be due to location lying between 1,830 meters (6,000 ft) and 2,440 meters (8,000 ft) above sea level and establishing of the settlements on steep slopes, receiving plenty of rainfall under the mountain climate with the extremely cold winter season, the existence of unstable and unconsolidated soil and lithology, extending construction of new roads and expansion of the existing roads, population growth and settling of more people in the urban area, and collapsing of big old pine trees. In conclusion, landslides in the study area are found resulting from combined activities of physical factors and human impacts.


2022 ◽  
Author(s):  
Novikova O.V ◽  
Gorshkov A.I.

Abstract This study is an attempt to determine potential tsunamigenic morphostructural nodes in mainland Greece using pattern recognition algorithms. The earthquakes that have produced local tsunamis in the region were confined to morphostructural nodes whose locations were found by morphostructural zoning. The recognition problem consisted in separating all nodes in the region into the tsunamigenic class and the non-tsunamigenic class based mainly on the geomorphologic parameters of the nodes. The data on tsunamigenic earthquakes in Greece for training the Cora-3 algorithm were taken from the GHTD global historical catalog of tsunamigenic events (http://www.ngdc.noaa.gov/hazard/tsu_db.shtml). The recognition procedure resulted in determining 27 tsunamigenic nodes, with most of these being situated in the southern tip of the Peloponnese Peninsula, as well as in the gulfs of Corinth and Patras. Three tsunamigenic nodes were identified in the area of the Malian Gulf on the Aegean coast of Greece. According to the relevant literature, most local tsunamis in Greece were initiated by submarine slides and slumps due to earthquakes. According to the characteristic geomorphologic features derived in this study, the tsunamigenic nodes are situated in settings of contrasting relief characterized by steep slopes. This favors submarine landslides when subjected to earthquake excitation. The results reported in this paper form a basis for developing a methodology to be used in long-term tsunami hazard assessment, supplying information on local potential tsunamigenic sources required for tsunami regionalization of coastal areas in Greece.


2022 ◽  
Vol 82 ◽  
Author(s):  
U. Habiba ◽  
M. Anwar ◽  
M. Hussain ◽  
R. Khatoon ◽  
K. A. Khan ◽  
...  

ABSTRACT Microhabitat factors associated with the habitat of barking deer (Muntiacus vaginalis) were examined and compared between summer and winter seasons. Habitat characteristics and preferred habitat were measured by locating direct and indirect signs. To quantify the habitat utilization of barking deer, each selected study site was sampled for floral diversity from 2015 to 2017. Quadrats were deployed along transect lines to determine seasonal distribution. Barking deer were not evenly distributed across vegetation types in the study area; they occurred more often in the broad-leaved forest than in Chir pine forest, at an elevational range of 550-850 m, in thick vegetation on steep slopes. The most preferred habitat included trees and shrubs with 30% and 69% cover, respectively. Barking deer avoided thicker tree cover, possibly as it hinders movement and escape from predators. No significant difference (χ2 = 6.37, df = 3, p = 0.19) in seasonal vegetation cover was recorded.


2022 ◽  
Vol 174 ◽  
pp. 106464
Author(s):  
Kirsten Ellis ◽  
Rosmarie Lohnes ◽  
Jeremy Lundholm
Keyword(s):  

2021 ◽  
Vol 9 ◽  
Author(s):  
Shakil Ahmad Romshoo ◽  
Aazim Yousuf ◽  
Sadaff Altaf ◽  
Muzamil Amin

Soil erosion is one of the serious environmental threats in the Himalayas, primarily exacerbated by the steep slopes, active tectonics, deforestation, and land system changes. The Revised Universal Soil Loss Equation was employed to quantify soil erosion from the Vishav watershed in the Kashmir Himalaya, India. Topography and land use/land cover (LULC) are important driving factors for soil erosion. Most often, a Digital Elevation Model (DEM) is used in erosion models without any evaluation and testing which sometimes leads to erroneous estimates of soil erosion. For the best topographic characterization of the watershed, four publicly available DEMs with almost identical resolution (∼30 m), were evaluated. The DEMs were compared with GPS measurements to determine the most reliable among the tested DEMs for soil erosion estimation. Statistical evaluation of the DEMs with GPS data indicated that the CARTO DEM is better with root mean square error (RMSE) of 18.2 m than the other three tested DEMs viz., Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Shuttle Radar Topography Mission (SRTM), and Advanced Land Observing Satellite (ALOS). Slope length and slope steepness factors were computed from the DEMs. Crop cover and management factors were generated from the satellite-derived LULC. Moreover, rainfall data of the nearest stations were used to compute rainfall erosivity and soil erodibility factor was derived from the soil texture data generated from 375 soil samples. The simulated erosion estimates from SRTM, ALOS, and CARTO DEMs showed similar spatial patterns contrary to the ASTER estimates which showed somewhat different patterns and magnitude. The mean erosion in the study area has almost doubled from 2.3 × 106 tons in 1981 to 4.6 × 106 tons in 2019 mainly driven by the anthropogenic LULC changes. The increased soil erosion is due to the degradation of forest cover, urbanization, steep slopes, and land system changes observed during the period. In absence of the observations, the simulated soil erosion was validated with the land degradation map of the watershed which showed a good correspondence. It is hoped that the results from this work would inform policymaking on soil and water conservation measures in the data-scarce mountainous Kashmir Himalaya.


2021 ◽  
Author(s):  
Adeel Liaqat ◽  
Yiheng Yin ◽  
Sabir Hussain ◽  
Wen Wen ◽  
Juanxia Wu ◽  
...  

Abstract As scaling down the size of metal oxide semiconductor field-effect transistors (FETs), power dissipation has become a major challenge. Lowering the sub-threshold swing (SS) is known as an effective technique to decrease the operating voltage of FETs and hence lower down the power consumption. However, the Boltzmann distribution of electrons (so-called ‘Boltzmann tyranny’) implements a physical limit to the SS value. Use of negative capacitance (NC) effect has enabled a new path to achieve a low SS below the Boltzmann limit (60 mV/dec at room temperature). In this work, we have demonstrated a NC-FET from an all two-dimensional (2D) metal ferroelectric semiconductor (MFS) vertical heterostructure: Graphene/CuInP2S6/MoS2. The negative capacitance from the ferroelectric CuInP2S6 has enabled the breaking of the “Boltzmann tyranny”. The heterostructure-based device has shown steep slopes switching below 60 mV/dec (lowest to <10 mV/dec) over 3 orders of source-drain current, which provides an avenue for all 2D material based steep slope FETs.


Author(s):  
Marianna Shipka

Ensuring the ecological sustainability of the territory is possible in the case of the optimal ratio of different types of lands. In particular, it is important to have sufficient areas of eco-stabilizing lands (forests, meadows, protected areas, etc.). Of great importance are the features of land use in coastal areas, areas with high steep slopes and areas with soils susceptible to degradation. Ecologically sustainable land use can reduce the risk of soil degradation processes, provide an optimal microclimate, good hydrological conditions and promote the protection of small rivers. To provide recommendations for improving the structure of land use in the Poltva river basin, a map of optimization of the structure of land use using the ArсGIS 10.0 program was drawn up. For this purpose, a map of slope steepness was constructed, an interpretation of space images was made to compile a map of land use structure and a map of the soil cover was digitized. As a result of the analysis of the map of land use structure the peculiarities of the ratio of types of lands in different parts of the studied territory by integral indicators are determined. The coefficients of anthropogenic load, ecological stability of land use, ecological stability of landscapes, ecological balance and others are calculated. Areas with different degrees of anthropogenic transformation of lands are identified. The relationship between the peculiarities of natural conditions (geological structure, relief, soil cover) and land use of the territory is analyzed. As a result of overlapping maps of slope steepness, soil cover and land use, areas with different risk of soil degradation processes and plowed coastal areas were identified. The map of land use structure optimization is compiled according to the method of allocation of ecological and technological groups of lands. According to this technique, lands are differentiated by the steepness of the slopes. The proposed optimization of land use involves the use of phytomeliorative and agrotechnical measures: plowing across the slope, soil-protective crop rotations, the creation of forest belts, land conservation, etc. Recommended optimization measures include the withdrawal from agricultural cultivation of peatlands, steep slopes, floodplains, hollows, coastal protection zones of rivers and streams. The implementation of the proposed optimization measures will reduce plowing, increase the share of eco-stabilizing lands and improve the integral indicators characterizing the ratio of different types of lands. A compiled map of land use structure optimization can be used for land management and environmental activities. Key words: anthropogenic load, land use, ecological and technological groups of lands, river basin, optimization, Bug river.


Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1612
Author(s):  
Sättar Ezzati ◽  
Farzam Tavankar ◽  
Mohammad Reza Ghaffariyan ◽  
Rachele Venanzi ◽  
Francesco Latterini ◽  
...  

Mountainous hardwood mixed stands offer challenges to timber harvesting operations in practice, including a harsh climate, variable topography, steep terrain, and large-sized timbers. This paper aims to develop productivity and cost models for a mountain-ground-based harvesting operation across the terrain (e.g., slope conditions), stand (e.g., tree volume) environmental (e.g., weather), and yard (e.g., winching distance) variables and to assess GHG emissions related to the equipment in use. This development was implemented in a timber harvesting practice under single-tree selection in mountainous forests of Iran where a motor-manual chainsaw is used for felling and a rubber-tired cable skidder is used for log extraction. The average delay-free productivity was 4.55 m3 for felling and 14.73 m3 h−1for skidding. Lower production costs and higher productivity rates were observed over the gentle slopes and in sunny conditions. The average production costs ranged between USD 4.27m−3 for felling and USD 5.35m−3 for skidding. The average emissions ranged between 0.96 kg m−3 for felling and 7.06 kg m−3 for skidding in snowy conditions over steep slopes. The study’s results confirm avoiding harvesting operations on steep slopes (greater than 35%) and in extreme weather conditions to obtain higher work efficiency and to minimize adverse effects of machinery on forest ecosystems. The results should be of use to harvest managers and forest planners considering the application of ground-based harvesting operations using a semi-mechanized system on a range of operating conditions in mountain hardwood stands.


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