WorldWideScience

Sample records for talus slopes

  1. New insights into the ground thermal regime of talus slopes with permafrost below the timberline

    Science.gov (United States)

    Schwindt, Daniel; Kneisel, Christof

    2013-04-01

    In the central Alps permafrost can be expected above 2400 m a.s.l., at altitudes where mean annual air temperatures are below -1° C. However, isolated permafrost occurrences are present in north-exposed talus slopes, far below the timberline, where mean annual air temperatures are positive. Driving factors are assumed to be a low income of solar radiation, a thick organic layer with high insulation capacities as well as the thermally induced chimney effect (Wakonigg, 1996). Investigated are three talus slopes with permafrost in the Swiss Alps that differ with regard to elevation level, talus material, humus characteristics and vegetation composition as well as the mean annual air temperatures. Aim is to achieve a deeper understanding of the factors determining the site-specific thermal regime, as well as the spatially limited and temporally highly variable permafrost occurrences in vegetated talus slopes. Focus is not solely on the question of why permafrost exists at these sites, but also why permafrost does not exist in the immediate surroundings. To detect the temporal variability and spatial heterogeneity of the permafrost occurrences, electrical resistivity tomography monitoring, seismic refraction tomography monitoring, and quasi-3D ERT were applied. To determine the ground thermal regime, air-, ground surface-, and humus temperatures, as well as temperatures within vents of the chimneys were recorded. Furthermore, humus characteristics (thickness, -temperature and -moisture) were mapped in permafrost-affected slope areas and in the immediate surroundings. To test the correlation between solar radiation, permafrost distribution, and humus/vegetation composition, digital elevation models were used to calculate the income of solar radiation. The areal extent of the permafrost bodies coincide precisely with slope sections where the organic layer is thickest, a consistent moss cover is present, and where temperatures at the transition between humus layer and talus material are lowest. The interaction of factors driving the ground thermal regime turned out to be more complex than assumed with differences between the investigated sites. Besides convective heat transport of the chimney effect, conductive heat flow within the humus layer strongly influences the ground thermal regime. Supercooling of the talus material in winter and autumn is aggravated by a high thermal conductivity of the organic material under frozen and wet conditions. The preservation of permafrost is favoured by the high insulation capacity of dry organic material in summer and by a prolonged zero-curtain period of up to 3 months - driven by high water-storage capacity of the organic material - that buffers the propagation of warm temperatures into the subsurface in spring. The income of solar radiation at the foot of the slope does not state a major driving factor for the occurrence of permafrost. Variability is low between areas with and without permafrost. In fact, differences were detected upslope, below the rock-walls, with summer-values being lowest in areas above the permafrost occurrences. It must be assumed that this affects the thermal circulation of the chimney effect during summer and favours the persistence of frozen ground in spatially limited slope areas.

  2. Paediatric talus fracture.

    LENUS (Irish Health Repository)

    Byrne, Ann-Maria

    2012-01-01

    Paediatric talus fractures are rare injuries resulting from axial loading of the talus against the anterior tibia with the foot in dorsiflexion. Skeletally immature bone is less brittle, with higher elastic resistance than adult bone, thus the paediatric talus can sustain higher forces before fractures occur. However, displaced paediatric talus fractures and those associated with high-energy trauma have been associated with complications including avascular necrosis, arthrosis, delayed union, neurapraxia and the need for revision surgery. The authors present the rare case of a talar neck fracture in a skeletally immature young girl, initially missed on radiological review. However, clinical suspicion on the part of the emergency physician, repeat examination and further radiographic imaging revealed this rare paediatric injury.

  3. Evidences of winter ascending air circulation throughout talus slopes and rock glaciers situated in the lower belt of alpine discontinuous permafrost (Swiss Alps)

    OpenAIRE

    Delaloye, Reynald; Lambiel, Christophe

    2005-01-01

    The winter ascending circulation of air throughout an accumulation of coarse slope sediments (the so-called chimney effect) facilitates the cooling of the ground and even the occurrence of permafrost in the lower part of a deposit. Simultaneously, any freezing is unlikely to occur in the upper part. The chimney effect has been reported to date mainly for cold and sometimes perennially frozen scree slopes situated at low elevations, far below the regional limit of the discontinuous mountain pe...

  4. Polli talus tehakse maailmatasemel kultuuri / Kaire Korpe

    Index Scriptorium Estoniae

    Korpe, Kaire

    2001-01-01

    Polli talu perenaine Marika Blossfeldt korraldab kolmandat suve oma talus kursusi, loenguid ja tantsuetendusi. Viimased kolm nädalat olid Polli talus õppelaagris koreograafid Baltimaadest ja Ida-Euroopast

  5. Completely extruded talus without soft tissue attachments

    OpenAIRE

    Jin-Soo Suh; Sang Woo Kim; Ho Seong Lee; Jae Jung Jeong; Young Rak Choi

    2011-01-01

    A completely extruded talus without any remaining soft tissue attachments is extremely rare. The present report describes treatment of a 45-year-old man who sustained a completely extruded talus injury following a rock-climbing fall. Upon admission, the extruded talus was deep-frozen in our bone bank. The open ankle joint underwent massive wound debridement and irrigation for 3 days. Four days later we performed a primary subtalar fusion between the extruded talus and the calcaneus, anticipat...

  6. Using cosmogenic nuclides from amalgamated talus cobbles to assess alpine erosion in the Teton Range

    Science.gov (United States)

    Tranel, L. M.

    2014-12-01

    Measuring spatial patterns and rates of erosion in alpine landscapes is challenging because locations are steep and remote, and hillslope processes including rockfalls, avalanches and landslides are stochastic. This study evaluates how variability between quantitative erosion rates and surface ages and qualitative weathering features on talus deposits may influence interpretations of the spatial distribution of hillslope erosion in the Teton Range. I use cosmogenic nuclide concentrations to estimate erosion rates and surface ages of bedrock and talus deposits. I then compare these cosmogenic nuclide results to talus volumetric estimates of erosion rates. I also compare the quantitative estimates of surface ages and erosion to qualitative weathering observations on talus cobbles. The resulting erosion rates from cosmogenic nuclides are slower than rates estimated from talus volumes, however, both methods produced the same pattern of erosion. The fastest and slowest cosmogenic nuclide and volumetric erosion rates were associated with the same fans. Exposure ages of talus surfaces decrease as elevation of the fans increase. Qualitative observations of weathering on cobble surfaces were not reliable to predict the relative rates of erosion on the talus fans. Using amalgamated samples from hillslope deposits adjacent to steep sided canyons for cosmogenic nuclide analysis has high uncertainty when finding accurate erosion rates or exposure ages due to complicated shielding on steeply sloping walls. The similar patterns of rapid or slow erosion rates, however, suggest that cosmogenic nuclides or volume estimates are both reasonable methods to understand relative timing of hillslope events, even if the absolute age or erosion rate cannot be determined.

  7. Completely extruded talus without soft tissue attachments

    Directory of Open Access Journals (Sweden)

    Young Rak Choi

    2011-04-01

    Full Text Available A completely extruded talus without any remaining soft tissue attachments is extremely rare. The present report describes treatment of a 45-year-old man who sustained a completely extruded talus injury following a rockclimbing fall. Upon admission, the extruded talus was deep-frozen in our bone bank. The open ankle joint underwent massive wound debridement and irrigation for 3 days. Four days later we performed a primary subtalar fusion between the extruded talus and the calcaneus, anticipating revascularization from the calcaneus. However, aseptic loosening and osteolysis developed around the screw and talus. At 12 months post-trauma we performed a tibiocalcaneal ankle fusion with a femoral head allograft to fill the talar defect. Follow-up at 24 months post-trauma showed the patient had midfoot motion, tibio-talar-calcaneal fusion, and was able partake in 4-hour physical activity twice per week.

  8. Lopsakalt rahvuslik mood Pulga talus / Tanel Veenre

    Index Scriptorium Estoniae

    Veenre, Tanel, 1977-

    2009-01-01

    Eesti Moekunstnike Ühenduse näitus "Lillemotiiv moevormil" Eesti Vabaõhumuuseumi Pulga talus. Osalevad Anne Metsis, Anneliis Vabul, Diana Denissova, Monika Kisand, Juta Piirlaid, Anu Hint ja moekunsti õppejõud Yumiko Okazaki Jaapanist. Eksponeeritud rõivamudelid on kaunistatud rahvuslikest tikanditest inspireeritud stiliseeritud kujunditega

  9. Magus suvelõpp Saare talus / Kaja Kurg

    Index Scriptorium Estoniae

    Kurg, Kaja, 1959-

    2011-01-01

    Saare talus Vändra lähistel Lüüste külas kasvatavad omanikud Harri Poom, Aivar ja Kaja Saar nii kilehoonetes kui avamaal mitmeid lõunamaa vilju, mis esindatud mitmete sortidega. Saare-Tõrvaaugu aiand pakub õppepäevadel degusteerimiseks meloneid, arbuuse, viinamarju, tomateid, kartuleid.

  10. Vanad sõbrad: Poola president õhtustas Ärma talus

    Index Scriptorium Estoniae

    2011-01-01

    President Toomas Hendrik Ilves võõrustas 28. märtsil 2011 Viljandimaal Ärma talus Poola presidenti Bronislaw Komorowskit. Poola riigipea abikaasa Anna Komorowska ja proua Evelin Ilves külastasid Tallinnas ka lastekirjanduse keskust, kus esitleti raamatut "Väike Chopin" ning tegid ekskursiooni Tallinna vanalinnas

  11. Talus avulsion fractures: are they accurately diagnosed?

    Science.gov (United States)

    Robinson, Karen P; Davies, Mark B

    2015-10-01

    Dorsal talus avulsion fractures occurring along the supination line of the foot can cause pain and discomfort. Examination of the foot and ankle using the Ottawa ankle rules does not include examination of the talus, an injury here is easily missed causing concern to the patient. This is a retrospective study carried out in a major trauma centre to look at the assessment and diagnosis of all patients with a dorsal talus and navicular avulsion fractures over a one year period. Nineteen patients with an isolated dorsal talus avulsion fracture and five patients with an isolated dorsal navicular fracture were included. The correct diagnosis was made in 12 of patients with isolated dorsal talus avulsion fractures, 7 patients were given an incorrect diagnosis after misreading of the radiograph. Four patients with a dorsal navicular avulsion fracture were given the correct diagnosis. If not correctly diagnosed on presentation patients can be overly concerned that a 'fracture was missed' which can lead to confusion and anxiety. Therefore these injuries need to be recognised early, promptly diagnosed, treated symptomatically and reassurance given. We recommend the routine palpation of the talus in addition to the examination set out in the Ottawa Ankle Rules and the close inspection of plain radiographs to adequately diagnose an injury in this area. PMID:26190632

  12. [Osteochondral lesions of the talus].

    Science.gov (United States)

    Biedert, R

    1989-04-01

    Osteochondral lesions occur either as osteochondral fractures (so called flake fractures) or osteochondritis dissecans. Both types of lesions are caused in the most of the cases by an adequate trauma. The injury is sustained during inversion of the ankle. If the foot is dorsiflexed, an anterolateral lesion will result from shearing forces by the fibula. If the inversed foot is plantar flexed and followed by rotation of the tibia on the talus, a postero-medial lesion will result from compression of the medial talar dome by the tibia, secondary to spiralling and shortening of the collateral ligaments. The diagnosis is suspected with the most common complaints of the patients to pain on weight bearing or during sports, swelling, crepitus, giving way or locking ankle after an inversion injury. In case of negative standard X-rays and doubtful clinical findings tomograms in the AP and lateral views or even a scintigraphy of both ankles ar indicated. 15 patients with osteochondral lesions were treated, 7 with an antero-lateral transchondral fracture and 8 with a poster-medial osteochondritis dissecans. The lesions were classified after Berndt and Harty and differentiated between type I-IV. 13 patients have been operated, 4 by arthroscopy. The mean follow-up time of the clinical and radiographic examination was 1 year. The results were evaluated by a point score system. 7 patients (46.6%) had good, 5 (33.3%) a fair and 3 (20%) a poor result.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2727716

  13. Multidisciplinary investigations on coupled rockwall-talus-systems (Turtmann valley, Swiss Alps)

    Science.gov (United States)

    Messenzehl, Karoline; Draebing, Daniel

    2015-04-01

    Talus slopes covering the base of steep, unstable rockwalls are characteristic periglacial landforms and major sediment storages in mountain systems. In the Turtmann valley (Swiss Alps), rockfall deposits account for 1/8 of the debris volume stored in the hanging valleys. To evaluate the spatio-temporal efficiency of rockfalls for long-term talus evolution, geophysical measurements on rockwalls and talus slopes are increasingly applied during the last decades. However, the correct interpretation of the geophysical data is still a difficult task due to the landforms' specific material properties. Moreover, no comprehensive geophysical study exists investigating the coupled rockwall-talus-system. Here, we studied two rockwalls and corresponding talus slopes in a tributary of the Turtmann valley. The active rockfall source areas dominate on rockwalls, for which a high permafrost probability was modelled (Nyenhuis et al. 2005). Rockwalls were selected based on their contrasting lithology, activity degree and valley location. By combining geophysical, geotechnical and geomorphological methods, we investigated (i) the rockwalls' mechanical characteristics as well as (ii) the material properties of the talus slopes in order to (iii) gain a further process understanding of the coupled rockwall-talus system. (i) At the rockwalls, Electrical Resistivity Tomography (ERT) and Seismic Refraction Tomography (SRT) were applied along 40-50m transects with an electrode/geophone spacing of 1-1.25m. In addition, detailed geotechnical surveys of the rock mass and its discontinuity properties were performed. The combined results reveal that high resistivity (>10'000k?m) and high p-wave velocities (>3'000m/s) correlate with dried bedrock consisting of amphibolites with large joint spacing (52cm) and long persistences (> 220cm). In contrast, the small joint spacing (17cm) and short persistences (electrode spacing, the block sizes (a, b, c-axis) of rockfall deposits were mapped in detail. The specific ERT seems to indicate the specific material properties, as high resistivities at the talus foot are linked to large block sizes, while patches of fine, relatively wet sediments near the apex are reflected by low resistivities. The very high p-wave velocities at the distal base of one of the talus may indicate the existence of ice. (iii) The synthesis of all data indicates that the joint spacing, lithology and the rock moisture patterns are major small-scale controls on the present-day destabilisation of the rockwalls, favouring the activity of wetting-drying and freeze-thaw cycles. Given the absence of permafrost in both rock faces, permafrost seems not to be relevant for the bedrock stability today, instead, unidirectional freezing on near-surface might be an effective breakdown mechanism. Depending on the contrasting rock mechanical and material properties of the rockwalls, different rockfall block sizes may be involved in the talus evolution, respectively. Therefore, our study reveals that the process understanding of the coupled rockwall-talus-system can be improved when geophysical data are interpreted in the light of the specific geotechnical and geomorphological landform conditions. Nyenhuis, M., M. Hoelzle, and R. Dikau, 2005, Rock glacier mapping and permafrost distribution modelling in the Turtmanntal, Valais, Switzerland, Zeitschrift für Geomorphologie, 49(3), 275-292.

  14. Sagittal bursting fracture of the talus

    International Nuclear Information System (INIS)

    Fractures of the talus have a relatively low incidence, accounting for 0.3% of all bone fractures and 3.4% of fractures of bones in the foot. These injuries affect the neck of the talus more frequently than is head or body. Because of the combined traumatic mechanism, sagittal fracture of the talar body is extremely rare; the literature containes only a few case reports, all with severe dislocation of the fragments. Plain film radiographs and CT pictures recorded in a rare case of nondisplaced fracture of the talar body are presented. (orig.)

  15. Thermal and Hydrologic Attributes of Rock Glaciers and Periglacial Talus Landforms; Sierra Nevada, California, USA

    Science.gov (United States)

    Millar, C. I.; Westfall, R. D.; Delany, D. L.

    2012-12-01

    To explore thermal regimes and hydrologic capacity of rock glaciers and related periglacial talus landforms, we deployed mini-thermochrons in and around potentially ice-embedded features of the Sierra Nevada. Results from studies at 13 rock glaciers and 8 taluses indicate that outlet springs from these landforms generally do not desiccate but persist year-round as ice (frozen) in winter and flowing water in the warm season. Temperatures of water (liquid and ice) in rock-glacier outlet springs had an annual mean of -0.2°C and mean of 0.6°C during the warm season with very low diurnal fluctuation. These and other attributes suggest the existence of internal ice and/or permafrost supplying the springs. Air temperatures of rock-glacier matrices (1 m below the surface) versus surface air corroborate the periglacial nature of internal environments: annual air temperatures of matrices were below freezing (mean, -0.8°C). Compared to surface air, especially during the warm season, matrix air temperatures were significantly colder and fluctuated less. Talus landforms followed a similar pattern, although water- and matrix air temperatures were warmer, and contrasts with surface air were not as strong as for rock glaciers. For rock glaciers and talus slopes, matrix air temperatures showed resistance (buffering) to changes in external air temperatures. Unique geomorphic conditions of rock glaciers and periglacial taluses in the Sierra Nevada appear to maintain cool-buffered thermal regimes at least partly decoupled from external air. Springs support persistent wetlands and lakes at their snouts, retaining water in otherwise semi-arid high cirques, and contribute as hydrologic reserves and critical habitat for alpine biota. Daily and seasonal lags and buffering effects suggest that ice within these landforms might resist surface warming on the longer term, which could make these landforms increasingly important as regional climates change.

  16. Simultaneous Bilateral Fracture Dislocation of the Talus: A Case Report

    OpenAIRE

    Mohammad Hosein Taraz-Jamshidi; Omid Shapari; Reza Shiravani; Saeed Moalemi; Ali Birjandinejad

    2013-01-01

    Introduction: Fracture - dislocations of the talus are typically due to high energy injuries. Displaced fracture - dislocations of the talus have poor outcomes in general and complications are common. Although talar fracture is common and comprises the second most common tarsal fracture, bilateral fracture - dislocations of the talus are rare. Not many reports regarding the subject can be found in the literature.Case Presentation: We report a patient with bilateral fracture - dislocations of ...

  17. Tibiotalar arthrodesis for injuries of the talus

    Directory of Open Access Journals (Sweden)

    Singh Jaswant

    2008-01-01

    Full Text Available Background: Fracture-dislocation of the talus is one of the most severe injuries of the ankle. Opinion varies widely as to the proper treatment of this injury. Since Blair?s original description of the tibiotalar fusion in 1943, there is little mention in the literature of his method. The present study reports the results of tibiotalar arthrodesis with modification in Blair?s technique. Materials and Methods: Eleven cases of modified Blair ? s tibiotalar arthrodesis were retrospectively studied. The average age was 32.4 years (range, 26-51 years. Six patients had posttraumatic avascular necrosis; five had neglected fracture-dislocation of the talus. Results: The mean followup is 8 years (range 3-12 years. Tibiotalar fusion was achieved in all the ankles at an average of 20.5 weeks (range 16-28 weeks. Nine cases having 15°-20° tibiopedal motion had excellent results and two ankles having 10°-15° of tibiopedal motion had good result. Conclusion: We achieved good long term results with tibiotalar arthrodesis with modification in Blair technique. The principal modification in the present study is retention of the talar body while performing arthrodesis with anterior sliding graft. The retention of the talar body provides intraoperative stability and in the long term, the retained talar body shares the load transmitted to the anterior and middle subtalar joints thus resulting in improved hind foot function and gait.

  18. Environmental impact of introducing plant covers in the taluses of orchard terraces: implications for erosion and agricultural runoff control

    OpenAIRE

    Rodriguez Pleguezuelo, C.R.; Duran Zuazo, V.H.; Francia Martinez, J.R.; Martin Peinado, F.J.; De Graaff, J.; Muriel Fernandez, J.L.

    2011-01-01

    South-eastern Spain, and in particular the coastal areas of Granada and Malaga, feature a large area under subtropical crops, with orchards established on terraces built along the slopes of the mountainous areas. The climate, characterized by periodically heavy rainfall, variable in space and time, and with the common agricultural practice of leaving the taluses with bare soil, are the main factors encouraging soil erosion, runoff, and subsequent transport of pollutants. Over a two-year perio...

  19. Mixed approach (numerical modeling / equilibrium analysis) for slope stability analysis: development and application to the dams and open pit mining; Une approche mixte (numerique/equilibre limite) pour le calcul de stabilite des ouvrages en terre: developpement et application aux barrages et talus miniers

    Energy Technology Data Exchange (ETDEWEB)

    Kourdey, A.

    2002-09-15

    The determination of the sliding surface of slope (dam, slope natural..) is one of the important and complicated problems in geotechnics. The Analyze of stability by the methods of Limit Equilibrium like the method of slices are the most used methods. They are able to determine a safety factor for a geometrically defined failure surface. These methods well adapted to the homogeneous mediums, have been developed a lot but they do not integrate the basic relations of mechanics (stress-strain). The numerical methods are better adapted to mediums having more complexity (effect of water, seismicity, fracturing,..). But, they are seldom used to determine a sliding surface and a safety factor. Each family offers appreciable advantages in the analysis of slope stability. For that purpose, we have developed a method that combines the advantages of the numerical methods as well as those of Limit Equilibrium allowing obtaining a slip surface determined by the calculated constraints. This slip surface may be imposed or better optimized, thus providing a minimal safety factor. Methods of operation research are used to obtain this surface. They are search methods by level, dynamic research.. or both at the same time. We integrated these developments in an existing computer code based on the method of Finite Differences known as FLAC. The stresses are determined for a linear behavior and for nonlinear. Interfaces and graphic tools are also produced to facilitate the analysis of stability. The validity of this approach was carried out for a standard case of slope, we analyzed and compared the results with the methods of Limit Equilibrium. The parametric study shows that this approach takes account of different parameters, which influences stability. We also kept a particular place for the application on real cases presenting slopes of different nature (dams, mining slops,...). (author)

  20. Multiple, distinct groundwater flow systems of a single moraine-talus feature in an alpine watershed

    Science.gov (United States)

    Roy, James W.; Hayashi, Masaki

    2009-06-01

    SummaryRecent studies suggest that talus slopes and moraines likely play an important role in groundwater flow and storage in alpine watersheds, though the subsurface processes of these unconsolidated sediment features are not fully understood. To gain insight into these groundwater systems, we investigated the spatial variability in groundwater properties and hydrological trends of a large spring and several nearby (?200 m) springs, discharging from a single moraine-talus feature in an alpine watershed in the Canadian Rockies. A key question was whether groundwater flow in these features is reasonably homogeneous. Hydrograph analyses revealed at least two different groundwater responses to precipitation and melt inputs: a rapid and likely localized response and a slower response indicating a subsurface connection to a nearby lake. There was also a large spread in groundwater composition across the large spring and between springs, including a consistent linear trend in major ion chemistry over a 20-m section of the large spring. The spatial and temporal trends in groundwater chemistry data suggests there are three groundwater components associated with this sediment feature, and that their relative contributions vary temporally, though the component associated with the lake appears dominant. The study findings suggest that unconsolidated sediment features can possess multiple, and possibly disconnected, groundwater flow paths exhibiting unique hydrological and geochemical characteristics, and cannot necessarily be treated as a single, homogeneous groundwater component when modeling the hydrology of alpine watersheds.

  1. Nonoperative treatment of closed total talus dislocation without fracture: A case report and literature review

    OpenAIRE

    Rhanim, Abdelkarim; Zanati, Rachid El; Younes Ouchrif; Hassani, Zouhir Ameziane; Kharmaz, Mohammed; Berrada, Mohammed Saleh

    2014-01-01

    Complete dislocation of the talus not accompanied by a fracture is a very rare injury. Most cases reported are open talus dislocations; closed dislocations are rarely seen. The functional prognosis is poor due to osteonecrosis of the talus which develops in the majority of cases.

  2. President Ilves võõrustas Ärma talus Poola riigipead / Raimo Poom

    Index Scriptorium Estoniae

    Poom, Raimo

    2008-01-01

    Poola president Lech Kaczynski ja tema abikaasa Maria Kaczynska külastasid president Toomas Hendrik Ilvest ja proua Evelin Ilvest Ärma talus Viljandimaal. Eesti riigipea rõhutas kohtumisel peamiselt Euroopa Liidu ja NATO teemasid ning väljendas rahulolematust Ignalina tuumajaama projekti kulgemise viisi ja tempo üle

  3. Raba talus tähistati "Vallatute kurvide" juubelit / Tõnis Tõnisson

    Index Scriptorium Estoniae

    Tõnisson, Tõnis, 1945-

    2009-01-01

    Raplamaal Mahtra külas Raba talus organiseeris Tallinnfilmi mängufilmis "Vallatud kurvid" keskset kaksikrolli mänginud Terje Luik filmi 50. juubelit (film esilinastus 28. 12. 1959) tähistava ürituse. Terje Luige elust. Muuseumitoas on väljas Saima Randjärv-Berlokko Kehtna kunstide koolis juhendatavate laste filmiainelised joonistused

  4. Ephemeral skin-flows on talus affected by permafrost degradation (Corral del Veleta, Spain)

    Science.gov (United States)

    Tanarro, L. M.; Palacios, D.; Zamorano, J. J.; Gómez, A.

    2009-04-01

    In mountain environments, talus formed at the foot of valley sides are frequently affected by hillslope processes, such as skin-flows. The main characteristic of this type of flow is that it only causes the movement of a thin layer of soil, regolith or debris over an inclined plane parallel to the topographical surface of the talus. Some examples of this movement have already been described (Rapp, 1960; Akerman; 1984; White, 1981, Benedict, 1970; Jahn, 1967; Söderman, 1980; Lewkowicz, 1988, Harris, 1987). The causes of the formation of these movements vary, but in general they have been linked primarily with rapid snow melt and/or with degraded permafrost levels (Jahn, 1967; Nyberg, 1991; Rapp and Nyberg, 1988; Strömquist, 1985; Hall, 1985; Thorn, 1988; McRoberts and Morgenstern, 1974, Caine, 1976). Within this context, the aims of this paper are: first, to present and describe the characteristics and temporal and geomorphological evolution of a series of skin-flows which have occurred on the talus which lies at the foot of the Corral del Veleta glacial cirque, and second, to analyze the factors that appear to have triggered them. The Pico del Veleta mountain (3398 m a.s.l.) is one of the main summits in the Sierra Nevada Massif, a group of mountains forming part of the Cordilleras Béticas, in SE Spain (37°03´N, 3°22´W). The Corral del Veleta is a glacial cirque on the northeastern face of the Pico del Veleta, c. 600 m long in a NW-SE direction, with a head is formed by a steep wall which falls more than 250 meters to meet with a wide and irregular talus. The cirque headwall is composed of metamorphic rocks (mainly micaschist), lined up in structural steps or shelves tilted towards the NNW. One of these shelves forms the base of the cirque, on which a series of moraine ridges, tardiglacial or from the Little Ice Age, which close off the cirque towards the North (Gómez et al., 2001). The talus is formed from abundant debris resulting from weathering (gelifraction) and hillslope dynamics (rockfall activity) which affect the headwall (Gómez et al., 2003) and is formed mainly by various talus cones which are irregular in shape and stepped as the accumulated debris covers the remains of the stepped structural shelves which were not destroyed by the glacial erosion. Although the talus debris is basically made up of blocks, it is important to point out the abundant presence of fine material, produced by the weathering of the micaschist. (Castillo and Fedeli, 2002; Gómez et al., 2003). Field work carried out over the last ten years (1998-2008) has allowed observation of the triggering and formation in some years of various skin flows in different sectors of the talus, especially in the late summer of 2002 when four skin flows occurred. Within this timeframe monitoring and analysis of this kind of skin flow has been carried out. On the one hand, the description of the morphology, morphometry and sedimentology of each flow has been completed with the production of detailed geomorphological mapping and from sedimentological analysis. The geomorphological mapping has, in turn, allowed the observation of the geomorphological evolution of the flows from the time they occurred. On the other hand, a study has been made of the variables or factors which seem a priori to control the triggering of the skin flow landslips: the snow melt and the presence of permafrost in the detrital talus. The former has been monitored through photographic control of the snow cover at the end of the summer season, so that for each date analyzed a map was obtained of the snow cover, superimposing in turn the location of the skin flows at that date. A GIS processing of the different snow covers has also allowed a map to be produced with the areas of maximum summer snow cover, which was compared with the sites of the skin flow landslips. The existence of permafrost and its presence in the detrital slope has been detected through the monitoring of the ground temperature (BTS measurements, miniature temperature dataloggers) and geophysical surveys (Gó

  5. Treatment of osteochondral lesions of the talus: a systematic review

    OpenAIRE

    Zengerink, M.; Struijs, P A A; Tol, J.L.; van Dijk, C. N.

    2009-01-01

    The aim of this study was to summarize all eligible studies to compare the effectiveness of treatment strategies for osteochondral defects (OCD) of the talus. Electronic databases from January 1966 to December 2006 were systematically screened. The proportion of the patient population treated successfully was noted, and percentages were calculated. For each treatment strategy, study size weighted success rates were calculated. Fifty-two studies described the results of 65 treatment groups of ...

  6. Quaternary-scale evolution of sequences of talus flatirons in the hyperarid Negev

    Science.gov (United States)

    Boroda, R.; Amit, R.; Matmon, A.; Aster Team; Finkel, R.; Porat, N.; Enzel, Y.; Eyal, Y.

    2011-04-01

    Talus flatiron sequences are ubiquitous landforms in arid and semiarid regions characterized by horizontal erodible rocks capped by more resistant rocks. Alternating phases of deposition and erosion lead to the formation of generations of talus flatirons in which ancient ones are located farther from the source cliff. The existing conceptual model of this systematic spatial distribution of talus flatirons is related to glacial-interglacial climatic cycles and to relatively high rates of cliff retreat. Three groups of talus flatirons were analyzed in the northeastern hyperarid Negev desert. The analyses include mapping, age determination using optically stimulated luminescence and cosmogenic nuclide exposure dating, electrical resistivity tomography and sedimentological and soil analyses. All talus flatirons contain gypsic-salic soil catena typical to hyperarid climate (< 80 mm yr - 1 ). No pedogenic indicators of past wetter environments such as buried calcic soil horizons, evidence of intense biogenic activity, or buried organic material were observed. 10Be exposure ages of the talus flatirons suggest that they were deposited during the middle Pleistocene; ~ 610 ka and ~ 170 ka for the oldest and intermediate-aged talus flatiron groups, respectively. These ages, combined with the present location of the talus flatirons relative to the source cliff yield retreat rates of 6-12 and ~ 200 m Ma - 1 for the bedrock cliff and talus flatiron apex, respectively, and in opposite directions. Our results show that (a) climatic changes at glacial-interglacial time scales are not the main controls over the formation of talus flatiron generation, and (b) that significant cliff retreat is not the main cause for the systematic spatial distribution of talus flatiron generations relative to the cliff. Our results indicate that the process of talus flatiron formation in the Negev desert must be associated with the balance between production, deposition, and removal of clasts under hyperarid conditions with only a minor cliff retreat.

  7. Can paleorefugia of cold-adapted species in talus slopes resist global warming?.

    Czech Academy of Sciences Publication Activity Database

    R?ži?ka, Vlastimil; Zacharda, M.; Šmilauer, P.; Ku?era, T.

    2015-01-01

    Ro?. 20, ?. 3 (2015), s. 403-412. ISSN 1239-6095 Grant ostatní: GA JU(CZ) 04-142/2010/P Institutional support: RVO:60077344 Keywords : global warming Subject RIV: EH - Ecology, Behaviour Impact factor: 1.481, year: 2014 http://www.borenv.net/BER/pdfs/ber20/ber20-403.pdf

  8. Morphometric Changes in Talus of Club Foot A Gross Observation in Human Foetuses Cambios Morfométricos en Talus del Pie Zambo, una Observación Macroscópica en Fetos Humanos

    OpenAIRE

    Fazal-ur-Rehman; Nafis A Faruqi

    2012-01-01

    Both the feet of six human foetuses of different age groups having unilateral club feet, were dissected for morphological study. Six morphometric parameters considered for comparing gross anatomical changes in normal and deformed feet, were 1-Maximum length of the talus, 2-Longitudinal dimension of head of talus, 3-Anterior trochlear breadth, 4-Maximum medial talar height, 5-Talar neck and calcaneal angle, 6-Talocalcaneal angle. All the foetuses with congenital club feet have almost similar d...

  9. Morphometric Changes in Talus of Club Foot A Gross Observation in Human Foetuses / Cambios Morfométricos en Talus del Pie Zambo, una Observación Macroscópica en Fetos Humanos

    Scientific Electronic Library Online (English)

    , Fazal-ur-Rehman; Nafis A, Faruqi.

    2012-03-01

    Full Text Available Para su estudio morfológico fueron disecados ambos pies de seis fetos humanos de distintas edades, uno de los pies era zambo. Seis parámetros morfométricos fueron considerados para la comparación de graves alteraciones anatómicas en los pies normales y deformes; estos fueron: 1. Longitud máxima del [...] talus, 2. Dimensión longitudinal de la cabeza del talus, 3. Ancho troclear anterior, 4. Altura medial máxima del talus, 5. Cuello talar y ángulo calcáneo, 6. Ángulo talocalcáneo. Todos los fetos con pie zambo congénito tienen una deformidad similar del esqueleto del pie. Las anomalías graves observadas fueron el menor tamaño del talus del pie zambo, aumento de la desviación media y retraso en el crecimiento plantar, deformación de la cabeza y región del cuello talar. También se observó una subluxación medial plantar del hueso navicular, con un consecuente deformidad de las facetas articulares de la cabeza del talus. La uniformidad y consistencia de las anomalías anatómicas fueron los rasgos más llamativos en este estudio. Abstract in english Both the feet of six human foetuses of different age groups having unilateral club feet, were dissected for morphological study. Six morphometric parameters considered for comparing gross anatomical changes in normal and deformed feet, were 1-Maximum length of the talus, 2-Longitudinal dimension of [...] head of talus, 3-Anterior trochlear breadth, 4-Maximum medial talar height, 5-Talar neck and calcaneal angle, 6-Talocalcaneal angle. All the foetuses with congenital club feet have almost similar deformity of foot skeleton. The gross anomalies observed were the smaller size of club foot talus and increased medial and planter deviation of a stunted, misshapen head and neck region. A medial plantar subluxation of the navicular bone with a consequent deformity of the articular facets of the talar head was also observed. Uniformity and consistency of anatomical abnormalities were striking features in present study.

  10. Morphometric Changes in Talus of Club Foot A Gross Observation in Human Foetuses Cambios Morfométricos en Talus del Pie Zambo, una Observación Macroscópica en Fetos Humanos

    Directory of Open Access Journals (Sweden)

    Fazal-ur-Rehman

    2012-03-01

    Full Text Available Both the feet of six human foetuses of different age groups having unilateral club feet, were dissected for morphological study. Six morphometric parameters considered for comparing gross anatomical changes in normal and deformed feet, were 1-Maximum length of the talus, 2-Longitudinal dimension of head of talus, 3-Anterior trochlear breadth, 4-Maximum medial talar height, 5-Talar neck and calcaneal angle, 6-Talocalcaneal angle. All the foetuses with congenital club feet have almost similar deformity of foot skeleton. The gross anomalies observed were the smaller size of club foot talus and increased medial and planter deviation of a stunted, misshapen head and neck region. A medial plantar subluxation of the navicular bone with a consequent deformity of the articular facets of the talar head was also observed. Uniformity and consistency of anatomical abnormalities were striking features in present study.Para su estudio morfológico fueron disecados ambos pies de seis fetos humanos de distintas edades, uno de los pies era zambo. Seis parámetros morfométricos fueron considerados para la comparación de graves alteraciones anatómicas en los pies normales y deformes; estos fueron: 1. Longitud máxima del talus, 2. Dimensión longitudinal de la cabeza del talus, 3. Ancho troclear anterior, 4. Altura medial máxima del talus, 5. Cuello talar y ángulo calcáneo, 6. Ángulo talocalcáneo. Todos los fetos con pie zambo congénito tienen una deformidad similar del esqueleto del pie. Las anomalías graves observadas fueron el menor tamaño del talus del pie zambo, aumento de la desviación media y retraso en el crecimiento plantar, deformación de la cabeza y región del cuello talar. También se observó una subluxación medial plantar del hueso navicular, con un consecuente deformidad de las facetas articulares de la cabeza del talus. La uniformidad y consistencia de las anomalías anatómicas fueron los rasgos más llamativos en este estudio.

  11. Rocks Exposed on Slope in Aram Chaos

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-550, 20 November 2003This spectacular vista of sedimentary rocks outcropping on a slope in Aram Chaos was acquired by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) on 14 November 2003. Dark piles of coarse talus have come down the slopes as these materials continue to erode over time. Note that there are no small meteor impact craters in this image, indicating that erosion of these outcrops has been recent, if not on-going. This area is located near 2.8oS, 20.5oW. The 200 meter scale bar is about 656 feet across. Sunlight illuminates the scene from the lower right.

  12. Magnetic Resonance Angiography in Clubfoot and Vertical Talus: A Feasibility Study

    OpenAIRE

    Kruse, Lisa; Gurnett, Christina A; Hootnick, David; Dobbs, Matthew B.

    2009-01-01

    Congenital vascular alterations of the normal adult arterial pattern have been associated with multiple congenital limb deformities including clubfoot and vertical talus. Investigators have observed absence of the anterior tibial artery and dorsalis pedis artery in most patients with clubfoot, and absence of the posterior tibial artery in all patients with vertical talus. We used magnetic resonance angiography to define the lower extremity vascular anatomy of two patients with left-sided vert...

  13. [Approach to open treatment of osteochondral lesions of the talus].

    Science.gov (United States)

    Seil, R; Rupp, S; Pape, D; Dienst, M; Kohn, D

    2001-01-01

    Arthroscopic techniques still represent the treatment of choice in osteochondral lesions of the talus (OLT). Open techniques may be used as an alternative or may be complementary to arthroscopic treatments. They are especially indicated in cases of large osteochondral lesions, difficult localisations and in cases of recurrent interventions. In addition to the type of treatment for the lesion itself, the choice of an ideal surgical approach is of paramount importance. Indications, operative technique, possible complications and rehabilitation are described in detail for each approach. Anterolateral, anteromedial, posterolateral and posteromedial soft-tissue approaches as well as medial and lateral malleolar osteotomies are discussed. If a distraction is not desired with arthroscopy, posteromedial and posterolateral soft-tissue approaches offer a good alternative for the treatment of posterior OLT. Osteotomy of the (medial) malleolus offers good visualisation of the medial talar dome. With the introduction of new techniques of osteochondral transplantations, the use of this approach is becoming more popular. However, it is an invasive technique and the risk of secondary osteoarthritis after malleolar osteotomy still needs to be determined. PMID:11227352

  14. Congenital vertical talus in four generations of the same family

    International Nuclear Information System (INIS)

    This paper presents four generations of a family with radiographically demonstrated congenital vertical talus (CVT) in whom a HOXD10 gene mutation was identified. Some members of the family with this mutation exhibited cavo-varus foot deformity consistent with a Charcot-Marie-Tooth (CMT)-like disorder. Physical examination was performed on nearly all of the affected and unaffected family members. DNA was extracted from blood obtained from 14 subjects who showed radiographic and clinical features of CVT (two of whom also had CMT), from two subjects with features of CMT but not CVT, and from 20 related family members who were clinically normal. Radiographs show the appearance of uncorrected CVT in infancy, in childhood, and in adulthood. DNA analysis revealed a mutation in a HOXD10gene located on chromosome 2 in all of the affected but none of the unaffected family members. There is an autosomal-dominant-inherited mutation with complete penetrance which is found in all members of a pedigree with CVT, some of whom exhibit a CMT-like foot disorder. Radiologic findings vary depending on the severity of involvement, treatment provided and age of the patient. (orig.)

  15. Approach alternatives for treatment of osteochondral lesions of the talus.

    Science.gov (United States)

    Navid, David O; Myerson, Mark S

    2002-09-01

    Osteochondral lesions of the talus are common injuries, especially in the athletic population. Although multiple etiologies exist, lateral lesions have a higher incidence of association with a specific traumatic event. It has been postulated that lateral lesions are produced when the anterolateral aspect of the talar dome impacts the fibula on application of an inversion or dorsiflexion stress to the ankle [2]. There is general agreement that surgery should be performed only in symptomatic cases, as osteochondral lesions of the talar dome show little tendency to progression and do not seem to lead to osteoarthritis [10,42]. Appropriate preoperative imaging is extremely important. Standard radiographs of the ankle supplemented with lateral plantar flexion and dorsiflexion views and CT or Mr imaging can be helpful in evaluating the size, depth, and exact location of the lesion. This information is essential in planning the appropriate surgical procedure. Although many stage I and II lesions respond well to conservative therapy and a period of immobilization, some higher-grade lesions (stage III and IV) eventually require surgical intervention. Most lesions can be approached arthroscopically. Many arthroscopic procedures have been shown to be successful, including debridement with abrasion chondroplasty, subchondral drilling, and microfracture [18-20]. But certain larger or refractory lesions may require an open approach to the ankle joint to restore the articular cartilage. Most lateral lesions have an anterior location and are easily accessible through a standard anterolateral approach. Most medial lesions are located on the posterior talar dome, and a medial malleolar osteotomy is usually required. Osteotomies, in particular of the medial malleolus, should be approached carefully. The possible complications of nonunion and malunion can lead to progressive arthritis of the ankle joint. PMID:12512414

  16. Determination of the internal structure of alpine talus deposits using different geophysical methods (Lechtaler Alps, Austria)

    Science.gov (United States)

    Sass, Oliver

    2006-10-01

    The total thickness and structure of alpine talus accumulations were investigated in a study area in the Northern Alps using ground-penetrating radar (GPR) completed by 2D-geoelectric (ERT) and seismic refraction soundings. The loose, steep talus cones of the Parzinn cirque are situated at an elevation of 2100-2300 m a.s.l. and end downslope at late-Glacial protalus ramparts. The surrounding rockwalls consist of "Hauptdolomit", a brittle dolostone. In most of the GPR profiles, the bedrock surface was clearly recognizable from the radargrams. Total talus thicknesses of up to 45 m were estimated. The uppermost talus layer is characterized by surface-parallel radar reflection patterns, intermediate resistivities (4-10 k? m) and low seismic velocities (400-500 m/s). These deposits are interpreted as stratified debris, built up during the Holocene by rockfall deposits occasionally resorted by debris flows. Below this unit, a zone of more irregular radar reflection patterns and enhanced electrical resistivities follows. The combined results lead to the assumption of very coarse grained, paraglacial rockfall deposits, or to a core of basal moraine beneath the talus. Some zones of especially high resistivity (> 25 k? m) may be related to sporadic permafrost occurrence in the depressions between the talus and the moraine ridges. Striped radar structures are also recognizable in the moraine bodies. The stratified sediments give evidence for glaciofluvial transport or debris flows as an agent of protalus rampart formation. However, these features probably result from a combination of different processes including periglacial creep. GPR turned out to be a powerful tool for the determination of debris volumes and internal structures. However, supporting geoelectric and seismic investigations are advisable to validate the results and to facilitate and improve the interpretation. The results point to an average Holocene rockwall retreat of 500 to 800 mm/ka, which is roughly three times higher than recent backweathering rates.

  17. Impact of land-use change on soil degradation by establishment of terraces with subtropical orchards in sloping areas (Granada, SE Spain)

    International Nuclear Information System (INIS)

    In the coast of Granada, an intensive irrigated agriculture based on subtropical crops has been established. These trees have been planted in highly sloped areas, by the construction of terraces. In this fragile Mediterranean agroecosystem, the removal of native spontaneous vegetation cover and substitution by orchards, increase the susceptibility to soil degradation and eventually brings up the destruction of these structures by rainfall events. To study this net change, we monitored the soil loss and runoff over a two-year period in the taluses of terraces with a mature mango (Mangifera indica L.) orchard. The studied treatments were bare soil (BS) and spontaneous vegetation (NSV), each twice replicated. The erosion plots were 4 m x 4 m in area and were located in the taluses of orchard in the taluses of orchard terraces (65 degree centigrade slope). The average annual soil loss by erosion for BS and NSV was 2.5 and 0.3 Mg ha-1 yr-1, and for runoff 34.1 and 6.8 mm yr-1, respectively. Therefore, soil erosion and runoff from BS plot were 8- and 5-times higher than in NSV, showing the importance of plant covers in the taluses of terraces in reducing this impact. Thus, the removal of plant cover from the taluses under these conditions, represent a high risk of slump and collapse, causing serious environmental and economic problems for farmers of subtropical crops. (Author) 11 refs.

  18. Impact of land-use change on soil degradation by establishment of terraces with subtropical orchards in sloping areas (Granada, SE Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Pleguezuelo, C. R.; Duran Zuzo, V. H.; Martin Peinado, F. J.; Franco Tarifa, D.

    2009-07-01

    In the coast of Granada, an intensive irrigated agriculture based on subtropical crops has been established. These trees have been planted in highly sloped areas, by the construction of terraces. In this fragile Mediterranean agroecosystem, the removal of native spontaneous vegetation cover and substitution by orchards, increase the susceptibility to soil degradation and eventually brings up the destruction of these structures by rainfall events. To study this net change, we monitored the soil loss and runoff over a two-year period in the taluses of terraces with a mature mango (Mangifera indica L.) orchard. The studied treatments were bare soil (BS) and spontaneous vegetation (NSV), each twice replicated. The erosion plots were 4 m x 4 m in area and were located in the taluses of orchard in the taluses of orchard terraces (65 degree centigrade slope). The average annual soil loss by erosion for BS and NSV was 2.5 and 0.3 Mg ha{sup -}1 yr{sup -}1, and for runoff 34.1 and 6.8 mm yr{sup -}1, respectively. Therefore, soil erosion and runoff from BS plot were 8- and 5-times higher than in NSV, showing the importance of plant covers in the taluses of terraces in reducing this impact. Thus, the removal of plant cover from the taluses under these conditions, represent a high risk of slump and collapse, causing serious environmental and economic problems for farmers of subtropical crops. (Author) 11 refs.

  19. Fraturas do colo do talus: avaliação da reprodutibilidade da classificação de Hawkins / Fractures of the neck of the talus: evaluation of reproducibility of Hawkins´s classification

    Scientific Electronic Library Online (English)

    Madson Lobato, Drummond Filho; Marcos Aurélio, Verzani; André Frazão, Rosa; Ciro Jabur, Pimenta; Jean, Grynwald; Alberto, Cliquet Junior.

    Full Text Available OBJETIVO: Avaliar a reprodutibilidade intra-observador e inter-observador da classificação de Hawkins para fraturas do colo do talus. MÉTODOS: Selecionou-se 20 casos aleatórios de fratura de tálus para serem definidos entre os tipos da classificação por oito cirurgiões ortopédicos, 13 residentes de [...] ortopedia e 15 de radiologia. RESULTADOS: Utilizando o teste estatístico de Landis e Kock foram obtidas médias de 0.627 e 0.668, na primeira e segunda avaliação, respectivamente. Tais valores definem uma concordância satisfatória para a classificação de Hawkins. CONCLUSÃO: Conclui-se que tal classificação é reprodutível entre observadores, possuindo melhores valores conforme maior experiência. Nível de Evidência I, Estudos diagnósticos - Investigação de um exame para diagnóstico. Abstract in english OBJECTIVE: To evaluate the intraobserver and interobserver reproducibility of Hawkins' classification for fractures of the neck of the talus. METHODS: 20 random cases of fracture of the talus were selected, to be defined according to the classification of types by eight orthopedic surgeons, 13 ortho [...] pedic residents and 15 radiology residents. RESULTS: Using the statistical test of Landis and Koch, measurements of 0.627 and 0.668 were obtained in the first and second evaluations, respectively. These values define a satisfactory agreement for Hawkins' classification. CONCLUSION: We conclude that this classification is reproducible between observers, with better values for the more experienced observers. Level of Evidence I, Study Diagnostic - Investigating a diagnostic test.

  20. Impact of erosion in the taluses of subtropical orchard terraces

    OpenAIRE

    Duran Zuazo, V.H.; Ruiz, J. A.; Raya, A.M.; Tarifa, D.F.

    2005-01-01

    The coast of the provinces of Granada and Malaga (SE Spain) are economically important areas for the subtropical fruit cultivation. The climate is characterized by heavy periodic rainfall, which is one of the main factors responsible for soil erosion in this agroecosystem. However, the erosion depends on a host of factors, including soil, topography, cropping and soil-conservation techniques. The most widely taken soil-conservation measure taken on steeply sloped coastal mountains in the zone...

  1. Fracture of the lateral process of the talus: appearance at MR imaging and clinical significance

    International Nuclear Information System (INIS)

    The case of a 59-year-old man with chronic lateral ankle pain following an inversion injury is presented. MR imaging performed to evaluate for soft tissue injury revealed an unsuspected fracture of the lateral process of the talus. The patient underwent surgical exploration of the fracture with debridement of adjacent loose bodies and is currently undergoing aggressive physical rehabilitation. (orig.)

  2. Storage and transmission of groundwater in alpine moraine and talus deposits (Invited)

    Science.gov (United States)

    Hayashi, M.; Hood, J.; Langston, G.; Muir, D.; McClymont, A. F.; Bentley, L. R.

    2010-12-01

    As the timing and amount of snow accumulation and melt are expected to change, temporary storage and release of snowmelt water in soil and groundwater may play important roles in buffering the effects of these changes in mountain headwaters. In high alpine environments devoid of vegetation, coarse deposits of moraine and talus have been reported in the literature as potential groundwater reservoirs, mainly based on chemical and isotopic evidences. However, relatively little is understood on physical processes of groundwater storage and transmission in alpine moraine and talus. We have conducted detailed investigation of groundwater processes in a glaciated catchment in the Canadian Rockies. Geophysical imaging, hydrological monitoring and analysis, tracer tests, and numerical simulations have shown that groundwater is stored in relatively thin saturated zones at the interface between moraine/talus deposits and the underlying bedrock. Flow and storage of groundwater appears to be controlled by the topography of bedrock surface, and location and connectivity of bedrock channels and depressions. Hydrological response times of moraine/talus systems are in the order of a few days to a few months, suggesting that these systems may buffer the changes in snow conditions over a time scale of one season, but not over multiple years.

  3. Neglected lateral process of talus fracture presenting as a loose body in tarsal canal

    Directory of Open Access Journals (Sweden)

    Bali Kamal

    2012-02-01

    Full Text Available ?Abstract?Lateral process fractures of talus are rare injuries with a potential to cause significant morbidity if misdiagnosed. The appropriate management of these fractures is still controversial and only a few reports are avai- lable on this subject. We presented a case of a 37-year-old male with neglected fracture on the lateral process of talus which was misdiagnosed at the time of injury. The patient presented to 7 months after misdiagnosis with a chronic ankle pain. Our case is unique in the sense that it is a rare case of neglected fracture on the lateral process of talus which presented as a loose body in sinus tarsi. However, a surgery with an excision of the loose body presented a satis- factory outcome along with 2 years?follow-up. To our knowledge, it ought to be the first case reported in the English literature. Through this case report, we highlight the importance of high index of suspicion for such rare bony injuries while evaluating trauma to the lateral side of ankle and discuss the principles of management of these fractures. Key words: Joint loose bodies; Subtalar joint; Talus

  4. Reimplantation of a completely extruded talus 8 days following injury: a case report.

    Science.gov (United States)

    Burston, Johnny L; Brankov, Boris; Zellweger, Rene

    2011-01-01

    We present the case of a 28-year-old female with 45 months follow-up after reimplantation of a completely extruded talus 8 days following the injury. The extruded talus was recovered at the site of the motor vehicle accident, where it had been embedded in the wreckage and subsequently transported to hospital 3 hours later. Thereafter, the talus was washed in an iodine solution for 5 hours and frozen for a period of 8 days at -80 °C, after which reimplantation surgery was undertaken. Throughout the extended follow-up period, no evidence of infection ever developed. Three years following her injury, the patient underwent fusion of the subtalar and talonavicular joints. At 45 months postoperative, imaging revealed avascular necrosis of the talar dome without substantial collapse. The patient progressed to the point where, at last follow-up, she was working in an administrative job and was able to bear full weight on the involved foot, despite development of mild pain on physical exertion. Despite the pain, moreover, she remained able to snow ski and to regularly walk 2 kilometers for cardiovascular fitness. We believe this case demonstrates that, in the apparent absence of deep infection, the development of avascular necrosis need not necessarily lead to a poor clinical outcome. Furthermore, this case showed that even after a period of 8 days in the freezer, and following antiseptic cleansing, the extruded talus could be reimplanted with a reasonable degree of clinical success. PMID:21106409

  5. Controls on Groundwater Flow in an Alpine Talus-Moraine Complex

    Science.gov (United States)

    Muir, D. L.; Hayashi, M.; Bentley, L. R.

    2009-05-01

    Since alpine watersheds are the headwaters of rivers acting as major sources of water, there is growing concern over water shortages in areas dependent on mountain runoff. Talus and moraine complexes, as well as fractured bedrock, are a dominant hydrologic response unit within the Lake O'Hara Research Basin (LORB) in Yoho National Park, British Columbia. In this alpine environment, previous studies have shown that groundwater plays an important hydrological role. Although little is known about groundwater storage in these media, they are likely a significant groundwater reservoir and an important control on groundwater flow. The goals of this study are to develop a conceptual model of the talus and moraine complex and the fractured bedrock. The approximately 0.3km2 Babylon drainage basin within the LORB was chosen as the study site as it contains a talus and moraine complex that drains into one gaugeable stream. The conceptual model of this basin has been developed using geophysical, hydrological and hydrogeological methods. Three Ground Penetrating Radar (GPR) and Electrical Resistivity Imaging (ERI) surveys were used to characterize the subsurface structure and water distribution within the talus and moraine complex. The bedrock surface is clearly defined in the GPR profiles and its elevation agrees with that in the ERI inversions. Highly resistive talus material is observable in the ERI results, and areas of low resistivity are found within the bedrock. Hydraulic conductivity estimates of the geologic media, calculated using tracer slug injection and baseflow recession analysis methods, fall within the ranges from gravel to fractured rock. Isotopic hydrograph separations indicate that groundwater is a significant contributor to stream discharge. Linear reservoir models show basin response times of up to 16 hours. The geophysical and hydrological evidence points toward two flow systems operating in the Babylon basin, those of flow through the fractured bedrock and flow through the talus and moraine complex. Understanding the hydrologic characteristics of alpine talus and moraine complexes and fractured bedrock is of great importance to increasing our knowledge of alpine hydrology. The results from this study will enable the estimation of hydrologic parameters of these geologic media and provide valuable information for the predictive modelling of mountain streams.

  6. Accumulation of Lead (Pb) in the Talus Lichenes Contained in Mahogany Tree Stands of Roadside of Medan City

    OpenAIRE

    Ashar Hasairin; Nurshara Pasaribu; Lisdar I. Sudirman; Retno Widhiastuti

    2014-01-01

    This study reports on the accumulation of lead (Pb) in the talus Lichenes found on roadside stands of mahogany trees in the city of Medan, North Sumatra, Indonesia. Samples were taken by purposive, ie location based on the level of traffic density with different air pollution. Pb analysis was performed using Atomic Absorption Spectroscopy (AAS). Identified as many as 8 kinds of Lichens with 2 types, namely talus Crustose and foliose. Type of Lepraria incana and Pertusaria amara, which is foun...

  7. Osteochondritis dissecans of the talus treated with the mosaicplasty technique: a case report.

    Science.gov (United States)

    Kodama, Narihito; Honjo, Masasi; Maki, Junichi; Hukuda, Sinsuke

    2004-01-01

    The authors present the use of osteochondral autografting with mosaicplasty technique performed on a 20-year-old man for a large osteochondral talar dome lesion. The patient had sustained a right ankle sprain many times while playing rugby football. The lesion measured 15 mm in diameter and encompassed more than one-third of the articular surface. After exposing the talus to a medial malleolar osteotomy, 3 osteochondral grafts taken from the medial femoral condyle of the ipsilateral knee were press-fit into the lesion. One year postoperatively, the patient has returned to playing rugby football. Radiographically, there was incorporation of the grafts. The authors believe that the mosaicplasty technique presents a promising new option in the treatment of osteochondritis dissecans of the talus. PMID:15181438

  8. Treatment of juvenile osteochondritis dissecans of the talus: current concepts review

    OpenAIRE

    VANNINI, FRANCESCA; CAVALLO, MARCO; BALDASSARRI, MATTEO; Castagnini, Francesco; OLIVIERI, ALESSANDRA; FERRANTI, ENRICO; BUDA, ROBERTO; GIANNINI, SANDRO

    2015-01-01

    Juvenile osteochondritis dissecans of the talus (JODT) affects the subchondral bone primarily and, in a skeletally immature population, articular cartilage secondarily. It probably consists of aseptic bone necrosis whose spontaneous healing is impaired by microtraumas, resulting in an osteochondral injury and, in some cases, in osteoarthritis. In many cases the clinical presentation is asymptomatic. Mild chronic pain is frequent, sometimes accompanied by swelling, stiffness or locking. Few da...

  9. Fracture of the lateral process of the talus: appearance at MR imaging and clinical significance

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, T.G.; Morrison, W.B. [Department of Radiology, Wilford Hall United States Air Force Medical Center, Lackland AFB, TX (United States); Ptaszek, A.J. [Department of Orthopaedic Surgery, Foot and Ankle Service, Wilford Hall United States Air Force Medical Center, Lackland AFB, Texas (United States)

    1999-04-01

    The case of a 59-year-old man with chronic lateral ankle pain following an inversion injury is presented. MR imaging performed to evaluate for soft tissue injury revealed an unsuspected fracture of the lateral process of the talus. The patient underwent surgical exploration of the fracture with debridement of adjacent loose bodies and is currently undergoing aggressive physical rehabilitation. (orig.) With 3 figs., 21 refs.

  10. [Osteoid osteoma of the talus: a rare cause for pain in the ankle joint].

    Science.gov (United States)

    Polzer, H; Polzer, S; Schieker, M; Mutschler, W; Regauer, M

    2014-07-01

    Osteoid osteomas are typically located in the femur and tibia and are mostly easy to diagnose based on patient age, the clinical signs and plain radiographs. In contrast, the diagnosis of osteoid osteomas of the foot is often delayed because of the atypical presentation. We report the case of a 24-year-old patient with persisting pain in the ankle joint over 8 years due to an osteoid osteoma of the talus neck. PMID:23949192

  11. Transient bone marrow edema of the talus: MR imaging findings in five patients

    International Nuclear Information System (INIS)

    Objective: To describe the MR findings of transient bone marrow edema (TBME) of the talus and to address the differential diagnostic considerations. Design and patients: The imaging findings of TBME of six tali were retrospectively reviewed in five patients with a clinical history of pain without trauma. Inclusion criteria were MR imaging findings that, when compared with clinical data and results of follow-up assessment, allowed the diagnosis of TBME. MR imaging, standard radiography, and bone scintigraphy were performed. The images were reviewed with particular attention to the pattern and distribution of abnormal marrow signal intensity as well as associated findings. Results: In four cases the entire talus was involved, and in two cases only a portion of the bone was affected. No fractures were detected. MR imaging demonstrated diffuse decreased signal intensity of the marrow on T1-weighted images with corresponding increased signal intensity on T2-weighted images. In all six cases MR imaging detected associated findings, which included joint effusion and soft tissue edema. All patients improved clinically with conservative therapy over a period of 6 months to 1 year. Conclusions: Although unusual, TBME can involve the talus. Marrow edema without evidence of a fracture and in the absence of history of trauma is a characteristic MR imaging feature, allowing confident diagnosis and institution of conservative therapy. (orig.)

  12. Epidemiological study on talus fractures / Estudo epidemiológico das fraturas do tálus

    Scientific Electronic Library Online (English)

    Marcos Hideyo, Sakaki; Guilherme Honda, Saito; Rafael Garcia de, Oliveira; Rafael Trevisan, Ortiz; Jorge dos Santos, Silva; Túlio Diniz, Fernandes; Alexandre Leme Godoy dos, Santos.

    2014-07-01

    Full Text Available Objetivo: Analisar as características dos indivíduos e das lesões encontradas em pacientes com fraturas de tálus. Métodos: Análise retrospectiva dos pacientes internados no Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo de 200 [...] 6 a 2011 com fratura de tálus. Foram estudados parâmetros associados ao perfil do paciente e fatores de risco, características da fratura, dados do tratamento e complicações agudas. Resultados: A análise dos 23 casos mostrou que os homens foram mais afetados do que as mulheres, com uma relação de 4,8:1. O mecanismo de trauma mais frequente foram os acidentes de trânsito, seguido pelas quedas de altura. O tipo de fratura mais frequente foi a do colo do tálus, com 17 casos. Dos 23 casos, sete apresentavam luxação peritalar no momento da apresentação, quatro tinham fratura exposta e 11 apresentavam outras fraturas associadas. O tempo médio entre o trauma e o tratamento definitivo foi de seis dias, enquanto o tempo médio de permanência hospitalar foi de 11 dias. Houve três pacientes que apresentaram complicações pós-operatórias agudas. Conclusão: A fratura do tálus foi mais comum na região do colo e mais frequente em jovens do gênero masculino que sofreram traumatismos de alta energia. Em quase metade dos casos houve fraturas associadas e o tempo de permanência hospitalar foi de 11 dias. Abstract in english Objective: To analyze the characteristics of patients with talus fractures and the injuries that they present. Methods: Retrospective analysis on patients hospitalized in the Institute of Orthopedics and Traumatology, Hospital das Clínicas, School of Medicine of the University of São Paulo, betwe [...] en 2006 and 2011, with talus fractures. Patient profile parameters, risk factors, fracture characteristics, treatment data and acute complications were analyzed. Results: Analysis on 23 cases showed that men were more affected than women, with a ratio of 4.8:1. The most frequent trauma mechanism was traffic accidents, followed by falls from a height. The most frequent type of fracture was at the neck of the talus, with 17 cases. Among the 23 cases, seven had peritalar dislocation at the time of presentation, four had exposed fractures and 11 presented other associated fractures. The mean length of time between the trauma and the definitive treatment was six days, while the mean length of hospital stay was 11 days. Three patients presented acute postoperative complications. Conclusion: Talus fractures occurred most commonly in the region of the talar neck and most frequently in young males who suffered high-energy trauma. In almost half of the cases, there were other associated fractures. The length of hospital stay was 11 days.

  13. Groundwater flow and storage within an alpine meadow-talus complex

    Directory of Open Access Journals (Sweden)

    A. F. McClymont

    2010-02-01

    Full Text Available The different types of geological deposits and rock formations found in alpine watersheds play key roles in regulating the rate and timing of runoff to mountain rivers. Talus and alpine meadows are dominant features in these areas, but scant data exist for their capacity to store and transmit groundwater. To gain further understanding of these processes, we have undertaken a combined geophysical and hydrological study of a small (2100 m2 alpine meadow and surrounding talus within the Lake O'Hara watershed in the Canadian Rockies. Several intersecting ground-penetrating radar (GPR and electrical resistivity tomography (ERT profiles and a seismic refraction profile were acquired to map the thickness of the talus and to image the topography of the bedrock basin that lies under the meadow. From analysis of the GPR and seismic profiles, we estimate that the talus deposits are relatively thin (<6 m. Combined interpretations from the GPR and ERT data show that the fine-grained sediment, that the meadow basin is comprised of, has a total volume of ca. 3300 m3 and has a maximum thickness of ca. 4 m. Annual snow surveys and stream gauging reveal that the total input volume of snowmelt and rainfall to the meadow basin is several times larger than its groundwater storage capacity, giving rise to low total-dissolved species concentrations (14–21 mg/L within the meadow groundwater. Observations from four piezometers established on the meadow show that the water table fluctuates rapidly in response to spring snowmelt and precipitation events but otherwise maintains a relatively stable depth of 0.3–0.4 m below the meadow surface during summer months. A slug test performed on one of the piezometers indicated that the saturated hydraulic conductivity of the shallow meadow sediments is 2.5×10?7 m/s. We suggest that a bedrock saddle imaged underneath the southern end of the meadow forms a natural constriction to subsurface flow out of the basin and helps to maintain the stable water-table depth.

  14. Groundwater flow and storage within an alpine meadow-talus complex

    Directory of Open Access Journals (Sweden)

    A. F. McClymont

    2010-06-01

    Full Text Available The different types of geological deposits and rock formations found in alpine watersheds play key roles in regulating the rate and timing of runoff to mountain rivers. Talus and alpine meadows are dominant features in these areas, but scant data exist for their capacity to store and transmit groundwater. To gain further understanding of these processes, we have undertaken a combined geophysical and hydrological study of a small (2100 m2 alpine meadow and surrounding talus within the Lake O'Hara watershed in the Canadian Rockies. Several intersecting ground-penetrating radar (GPR and electrical resistivity tomography (ERT profiles and a seismic refraction profile were acquired to map the thickness of the talus and to image the topography of the bedrock basin that underlies the meadow. From analysis of the GPR and seismic profiles, we estimate that the talus deposits are relatively thin (<6 m. Combined interpretations from the GPR and ERT data show that the fine-grained sediment comprising the meadow basin has a total volume of ca. 3300 m3 and has a maximum thickness of ca. 4 m. Annual snow surveys and stream gauging reveal that the total input volume of snowmelt and rainfall to the meadow basin is several times larger than its groundwater storage capacity, giving rise to low total-dissolved species concentrations (14–21 mg/L within the meadow groundwater. Observations from four piezometers established on the meadow show that the water table fluctuates rapidly in response to spring snowmelt and precipitation events but otherwise maintains a relatively stable depth of 0.3–0.4 m below the meadow surface during summer months. A slug test performed on one of the piezometers indicated that the saturated hydraulic conductivity of the shallow meadow sediments is 2.5×10?7 m/s. We suggest that a bedrock saddle imaged underneath the southern end of the meadow forms a natural constriction to subsurface flow out of the basin and helps to maintain the stable water-table depth.

  15. Groundwater flow and storage within an alpine meadow-talus complex

    Science.gov (United States)

    McClymont, A. F.; Hayashi, M.; Bentley, L. R.; Muir, D.; Ernst, E.

    2010-06-01

    The different types of geological deposits and rock formations found in alpine watersheds play key roles in regulating the rate and timing of runoff to mountain rivers. Talus and alpine meadows are dominant features in these areas, but scant data exist for their capacity to store and transmit groundwater. To gain further understanding of these processes, we have undertaken a combined geophysical and hydrological study of a small (2100 m2) alpine meadow and surrounding talus within the Lake O'Hara watershed in the Canadian Rockies. Several intersecting ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) profiles and a seismic refraction profile were acquired to map the thickness of the talus and to image the topography of the bedrock basin that underlies the meadow. From analysis of the GPR and seismic profiles, we estimate that the talus deposits are relatively thin (<6 m). Combined interpretations from the GPR and ERT data show that the fine-grained sediment comprising the meadow basin has a total volume of ca. 3300 m3 and has a maximum thickness of ca. 4 m. Annual snow surveys and stream gauging reveal that the total input volume of snowmelt and rainfall to the meadow basin is several times larger than its groundwater storage capacity, giving rise to low total-dissolved species concentrations (14-21 mg/L) within the meadow groundwater. Observations from four piezometers established on the meadow show that the water table fluctuates rapidly in response to spring snowmelt and precipitation events but otherwise maintains a relatively stable depth of 0.3-0.4 m below the meadow surface during summer months. A slug test performed on one of the piezometers indicated that the saturated hydraulic conductivity of the shallow meadow sediments is 2.5×10-7 m/s. We suggest that a bedrock saddle imaged underneath the southern end of the meadow forms a natural constriction to subsurface flow out of the basin and helps to maintain the stable water-table depth.

  16. Recurrent parosteal osteosarcoma of the talus in a 2-year-old child

    International Nuclear Information System (INIS)

    Parosteal osteosarcoma is an uncommon, low-grade malignant bone tumor and is found in an older age group than conventional osteosarcoma. We present a talar parosteal osteosarcoma that recurred twice in a 2-year-old child. To our knowledge, this is the youngest patient reported with a parosteal osteosarcoma. The talus is an unusual site for parosteal osteosarcoma. Inadequate resection due to a diagnosis of juxtacortical chondroma resulted in recurrence of the tumor. The age of the patient, the thick cartilaginous cap, and well-differentiated trabecular bone all contributed to the critical erroneous diagnosis. (orig.)

  17. Arthroscopic treatment of osteochondral lesions of the talus: microfracture and drilling versus debridement.

    Science.gov (United States)

    Backus, Jonathon D; Viens, Nicholas A; Nunley, James A

    2012-01-01

    Operative treatment of osteochondral lesions of the talus (OLTs) is frequently based on lesion size, stability, and surgeon preference. The purpose of this study was to determine if one arthroscopic treatment is superior to another for improving pain in patients with OLTs. Sixty-two patients treated by a single surgeon from 1999 to 2009 had sufficient medical records to be reviewed. Demographics, mechanism of injury, type of operation, lesion characteristics, and pain scores were analyzed. Thirty-one males and 31 females (mean age 32) were included; 54.1% of the lesions were on the medial talar dome and 72.3% were posttraumatic. Seventeen patients underwent arthroscopic debridement and 45 underwent arthroscopic drilling or microfracture. Visual analog scale pain scores were documented in 33 patients, demonstrating a statistically significant decrease at 6 months for debridement (p = .006) and drilling and microfracture (p = .0003) procedures. Neither procedure was superior to the other in pain reduction. No demographic variables were identified that influenced these postoperative pain scores. These results support that most OLTs are posttraumatic lesions caused by inversion or twisting and often occur on the medial talus. Arthroscopic interventions were effective for decreasing pain in both surgical groups. PMID:23327846

  18. Possible application of CT morphometry of the calcaneus and talus in forensic anthropological identification.

    Science.gov (United States)

    Inamori-Kawamoto, Osamu; Ishikawa, Takaki; Michiue, Tomomi; Mustafa, Asmaa Mohammed Hishmat; Sogawa, Nozomi; Kanou, Tetsuya; Oritani, Shigeki; Maeda, Hitoshi

    2016-03-01

    Computed tomography (CT) data provide information for volumetric and radiographic density analysis. The present study investigated the application of virtual CT volumetry of the tarsal bones to estimation of the sex, stature, and body weight using postmortem CT (PMCT) data of forensic autopsy cases. Three-dimensional (3D) images of the bilateral foot bones of intact Japanese subjects after adolescence (age ≥15 years, n = 179, 100 males and 79 females) were reconstructed on an automated CT image analyzer system. Measured parameters were mass volume, mean CT value (HU), and total CT value of the talus and calcaneus. Mean CT values of these bones showed age-dependent decreases in elderly subjects over 60 years of age for both sexes, with significant sex-related differences especially in the elderly. The mass volumes and total CT values of the talus and calcaneus showed significant sex-related differences, and also moderate correlations with body height and weight for bilateral bones in all cases (r = 0.58-0.78, p sex and stature in forensic identification; however, greater variations should be considered in body weight estimations of females. PMID:26362306

  19. Tarsal Tunnel Syndrome Secondary to an Unreported Ossicle of the Talus: A Case Report.

    Science.gov (United States)

    Sweed, Tamer Ahmed; Ali, Seyed Asghar; Choudhary, Surabhi

    2016-01-01

    Tarsal tunnel syndrome (TTS) is a compression neuropathy of the posterior tibial nerve in the tarsal tunnel. In about 80% of patients, a specific cause can be identified for TTS. We present a case of TTS secondary to an ossicle in close relation to the talus that, to our knowledge, has not previously been reported. A 26-year-old male presented with left ankle and foot pain that increased with activity and playing football. He had a tingling sensation and paresthesia in the sole and medial border of the foot along the distribution of the medial and lateral plantar nerves. Clinically, he had hard swelling at the floor of the tarsal tunnel, and Tinel's sign was positive. Computed tomography showed an accessory ossicle articulating with the posteromedial aspect of the talus, separating the flexor digitorum longus and flexor hallucis longus tendons, with tenosynovitis of the tibialis posterior, flexor digitorum longus and flexor hallucis longus tendons. Surgical release of the tarsal tunnel and excision of the ossicle were performed. Postoperatively, the patient showed dramatic improvement and had no complications or recurrence of symptoms after 8 months of follow-up. More interestingly, to the best of our knowledge, this ossicle has not been previously reported to cause TTS. PMID:25441278

  20. Investigations of slope stability

    Energy Technology Data Exchange (ETDEWEB)

    Nonveiller, E.

    1979-01-01

    The dynamics of slope slides and parameters for calculating slope stability is discussed. Two types of slides are outlined: rotation slide and translation slide. Slide dynamics are analyzed according to A. Heim. A calculation example of a slide which occurred at Vajont, Yugoslavia is presented. Calculation results differ from those presented by Ciabatti. For investigation of slope stability the calculation methods of A.W. Bishop (1955), N. Morgenstern and M. Maksimovic are discussed. 12 references

  1. Total Dislocation of the Talus without a Fracture. Open or Closed Treatment? Report of Two Cases and Review of the Literature

    OpenAIRE

    Xarchas, K.C.; Psillakis, I.G; Kazakos, K.J; Pelekas, S; Ververidis, A.N; Verettas, D.A

    2009-01-01

    Complete dislocation of the talus not accompanied by a fracture is a very rare injury. The injury is encountered as a closed one even more rarely. Reviewing the literature we found that proposed treatments for total talus dislocation varied from primary talectomy or arthodesis (to avoid complications) to closed reduction and an under knee cast. Most importantly, there was no agreement among authors about the method of reduction (open/closed). We report our experience with two cases of closed ...

  2. Retrograde Percutaneous Drilling for Osteochondritis Dissecans of the Head of the Talus: Case Report and Review of the Literature.

    Science.gov (United States)

    Corominas, Laura; Sanpera, Ignacio; Masrouha, Karim; Sanpera-Iglesias, Julia

    2014-10-31

    Osteochondral lesions of the talus might be a more common cause of pain than previously recognized, especially among those involved in athletic activities. However, the location of an osteochondral lesion on the talar head is much less common than such lesions localized to the dome of the talus and can pose diagnostic difficulties. We present the case of a 14-year-old soccer player who complained of longstanding pain in his left foot. After unsuccessful conservative treatment consisting of rest and bracing, he was ultimately treated with retrograde percutaneous drilling of the talar head performed by a medial approach. This was followed by casting and non-weightbearing for 6 weeks, after which physical therapy was undertaken. He was able to return to full activity and remained asymptomatic during a 5-year observation period. Although rare, osteochondritis dissecans of the talar head should be considered in young athletes with persistent foot pain that is unresponsive to reasonable therapy. PMID:25459089

  3. Closed subtalar dislocation with non-displaced fractures of talus and navicular: a case report and review of the literature

    OpenAIRE

    Fotiadis, Elias; Lyrtzis, Christos; Svarnas, Theodoros; Koimtzis, Miltos; Akritopoulou, Kiriaki; Chalidis, Byron

    2009-01-01

    Closed subtalar dislocations associated with talus and navicular fractures are rare injuries. We report on a case of a 43-year-old builder man with medial subtalar dislocation that was further complicated by minimally displaced talar and navicular fractures. Successful closed reduction under general anesthesia was followed by non-weight bearing and ankle immobilization with a below-knee cast for 6 ;weeks. At 3 years post-injury, the subtalar joint was stable, the foot and ankle mobility was i...

  4. Snowboard, wakeboard, dashboard? Isolated fracture of the lateral process of the talus in a high-speed road traffic accident.

    LENUS (Irish Health Repository)

    Ng, Evangeline Shimei

    2013-01-01

    We present a 23-year-old man who sustained an isolated fracture of the lateral process of the talus (LPT) in a head-on vehicle collision at a combined speed of 200 km\\/h. The driver of the other vehicle sustained fatal injuries at the scene. The LPT was openly reduced and fixed with successful outcome at 3 months. This case is unusual in the method of injury, in particular in relation to the isolated relatively minor injury sustained.

  5. Imaging of fractures of the lateral process of the talus, a frequently missed diagnosis

    International Nuclear Information System (INIS)

    Although if fractures of the lateral process of the talus (LPT) have been considered rare the widespread diffusion in snowboard practice has resulted in a dramatic increase in their frequency. If unrecognized they can result in secondary osteoarthritis of the ankle and/or talo-calcaneal joints and chronic pain and stiffness. Due to the complex anatomy of the region, these fractures are difficult to detect by standard radiographs. A high degree of suspicion is then necessary to diagnose them. Once suspected on the basis of physical examination and/or non concluding radiographs, computed tomography (CT) is the best modality to confirm the diagnosis and accurately appreciate the number of the fragments and their position which have therapeutic consequences (medical vs. surgical treatment). A better knowledge of these lesions seems necessary to the general radiologist to allow an early diagnosis in order to avoid chronic sequel. The purpose of this article is to report three additional cases of LPT fractures and discuss their pathogenesis, diagnosis and treatment

  6. Imaging of fractures of the lateral process of the talus, a frequently missed diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Bonvin, Florent; Montet, Xavier; Copercini, Michele; Martinoli, Carlo; Bianchi, Stefano E-mail: stefano.bianchi@hcuge.ch

    2003-07-01

    Although if fractures of the lateral process of the talus (LPT) have been considered rare the widespread diffusion in snowboard practice has resulted in a dramatic increase in their frequency. If unrecognized they can result in secondary osteoarthritis of the ankle and/or talo-calcaneal joints and chronic pain and stiffness. Due to the complex anatomy of the region, these fractures are difficult to detect by standard radiographs. A high degree of suspicion is then necessary to diagnose them. Once suspected on the basis of physical examination and/or non concluding radiographs, computed tomography (CT) is the best modality to confirm the diagnosis and accurately appreciate the number of the fragments and their position which have therapeutic consequences (medical vs. surgical treatment). A better knowledge of these lesions seems necessary to the general radiologist to allow an early diagnosis in order to avoid chronic sequel. The purpose of this article is to report three additional cases of LPT fractures and discuss their pathogenesis, diagnosis and treatment.

  7. MRI-guided percutaneous retrograde drilling of osteochondritis dissecans of the talus: a feasibility study

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the feasibility of MRI guidance for percutaneous retrograde drilling in the treatment of osteochondritis dissecans of the talus (OCDT). Four patients, one juvenile and three adults, with one OCDT lesion each and persisting ankle pain after conservative treatment, were treated with MRI-guided retrograde drilling. All lesions were stable and located in the middle or posterior medial third of the talar dome. Pain relief and the ability to return to normal activities were assessed during clinical follow-up. MRI and plain film radiographs were used for imaging follow-up. Technical success was 100 % with no complications and with no damage to the overlying cartilage. All patients experienced some clinical benefit, although only one had complete resolution of pain and one had a relapse leading to surgical treatment. Changes in the pathological imaging findings were mostly very slight during the follow-up period. MRI guidance seems accurate, safe and technically feasible for retrograde drilling of OCDT. Larger series are needed to reliably assess its clinical value. (orig.)

  8. MRI-guided percutaneous retrograde drilling of osteochondritis dissecans of the talus: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Kerimaa, Pekka; Ojala, Risto; Markkanen, Paula; Tervonen, Osmo; Blanco Sequeiros, Roberto [Oulu University Hospital, Department of Radiology, Oulu (Finland); Sinikumpu, Juha-Jaakko; Korhonen, Jussi [Oulu University Hospital, Department of Paediatric Surgery, Oulu (Finland); Hyvoenen, Pekka [Oulu University Hospital, Department of Surgery, Oulu (Finland)

    2014-07-15

    The purpose of this study was to evaluate the feasibility of MRI guidance for percutaneous retrograde drilling in the treatment of osteochondritis dissecans of the talus (OCDT). Four patients, one juvenile and three adults, with one OCDT lesion each and persisting ankle pain after conservative treatment, were treated with MRI-guided retrograde drilling. All lesions were stable and located in the middle or posterior medial third of the talar dome. Pain relief and the ability to return to normal activities were assessed during clinical follow-up. MRI and plain film radiographs were used for imaging follow-up. Technical success was 100 % with no complications and with no damage to the overlying cartilage. All patients experienced some clinical benefit, although only one had complete resolution of pain and one had a relapse leading to surgical treatment. Changes in the pathological imaging findings were mostly very slight during the follow-up period. MRI guidance seems accurate, safe and technically feasible for retrograde drilling of OCDT. Larger series are needed to reliably assess its clinical value. (orig.)

  9. Treatment of juvenile osteochondritis dissecans of the talus: current concepts review.

    Science.gov (United States)

    Vannini, Francesca; Cavallo, Marco; Baldassarri, Matteo; Castagnini, Francesco; Olivieri, Alessandra; Ferranti, Enrico; Buda, Roberto; Giannini, Sandro

    2014-01-01

    Juvenile osteochondritis dissecans of the talus (JODT) affects the subchondral bone primarily and, in a skeletally immature population, articular cartilage secondarily. It probably consists of aseptic bone necrosis whose spontaneous healing is impaired by microtraumas, resulting in an osteochondral injury and, in some cases, in osteoarthritis. In many cases the clinical presentation is asymptomatic. Mild chronic pain is frequent, sometimes accompanied by swelling, stiffness or locking. Few data are currently available on this topic and, moreover, most existing data were obtained from mixed groups and populations; it is therefore difficult to outline a scheme for the treatment of JODT. However, the most suitable treatment in the first stages of the disease is conservative. The presence of a loose body is an indication for surgical fixation, drilling or regenerative procedures, depending on the presence/extent of subchondral bone sclerosis and the surgeon's experience. Drilling has been shown to promote the healing of lesions with minimal surgical trauma. Microfractures, since they induce fibrocartilage repair, are to be considered only for small injuries. Mosaicplasty and osteochondral autograft transplantation may cause donor site morbidity and are techniques little reported in JODT. Regenerative techniques and fresh allografts give good results in osteochondral lesions, but further studies are required to describe the results that can be obtained in JODT alone. PMID:25750908

  10. Runoff from armored slopes

    International Nuclear Information System (INIS)

    Models exist for calculating overland flow on hillsides but no models have been found which explicitly deal with runoff from armored slopes. Flow on armored slopes differs from overland flow, because substantial flow occurs beneath the surface of the rock layer at low runnoff, and both above and below the surface for high runoff. In addition to the lack of a suitable model, no estimates of the PMP exist for such small areas and for very short durations. This paper develops a model for calculating runoff from armored embankments. The model considers the effect of slope, drainage area and ''flow concentration'' caused by irregular grading or slumping. A rainfall-duration curve based on the PMP is presented which is suitable for very small drainage areas. The development of the runoff model and rainfall-duration curve is presented below, along with a demonstration of the model on the design of a hypothetical tailings embankment

  11. Arctic Submarine Slope Stability

    Science.gov (United States)

    Winkelmann, D.; Geissler, W.

    2010-12-01

    Submarine landsliding represents aside submarine earthquakes major natural hazard to coastal and sea-floor infrastructure as well as to coastal communities due to their ability to generate large-scale tsunamis with their socio-economic consequences. The investigation of submarine landslides, their conditions and trigger mechanisms, recurrence rates and potential impact remains an important task for the evaluation of risks in coastal management and offshore industrial activities. In the light of a changing globe with warming oceans and rising sea-level accompanied by increasing human population along coasts and enhanced near- and offshore activities, slope stability issues gain more importance than ever before. The Arctic exhibits the most rapid and drastic changes and is predicted to change even faster. Aside rising air temperatures, enhanced inflow of less cooled Atlantic water into the Arctic Ocean reduces sea-ice cover and warms the surroundings. Slope stability is challenged considering large areas of permafrost and hydrates. The Hinlopen/Yermak Megaslide (HYM) north of Svalbard is the first and so far only reported large-scale submarine landslide in the Arctic Ocean. The HYM exhibits the highest headwalls that have been found on siliciclastic margins. With more than 10.000 square kilometer areal extent and app. 2.400 cubic kilometer of involved sedimentary material, it is one of the largest exposed submarine slides worldwide. Geometry and age put this slide in a special position in discussing submarine slope stability on glaciated continental margins. The HYM occurred 30 ka ago, when the global sea-level dropped by app. 50 m within less than one millennium due to rapid onset of global glaciation. It probably caused a tsunami with circum-Arctic impact and wave heights exceeding 130 meters. The HYM affected the slope stability field in its neighbourhood by removal of support. Post-megaslide slope instability as expressed in creeping and smaller-scaled slides are the consequence. Its geometrical configuration and timing is different from submarine slides on other glaciated continental margins. Thus, it raises the question whether slope stability within the Arctic Ocean is governed by processes specific to this environment. The extraordinary thick slabs (up to 1600 m) that were moved translationally during sliding rise the question on the nature of the weak layers associated with this process. Especially theories involving higher pore pressure are being challenged by this observation, because either extreme pore pressures or alternative explanations (e.g. mineralogical and/or textural) can be considered. To assess the actual submarine slope stability and failure potential in the Arctic Ocean, we propose to drill and recover weak layer material of the HYM from the adjacent intact strata by deep drilling under the framework of Integrated Ocean Drilling Program. This is the only method to recover weak layer material from the HYM, because the strata are too thick. We further propose to drill into the adjacent deforming slope to identify material properties of the layers acting as detachment and monitor the deformation.

  12. Slope constrained Topology Optimization

    DEFF Research Database (Denmark)

    Petersson, J.; Sigmund, Ole

    1998-01-01

    The problem of minimum compliance topology optimization of an elastic continuum is considered. A general continuous density-energy relation is assumed, including variable thickness sheet models and artificial power laws. To ensure existence of solutions, the design set is restricted by enforcing pointwise bounds on the density slopes. A finite element discretization procedure is described, and a proof of convergence of finite element solutions to exact solutions is given, as well as numerical ex...

  13. Enucleación medial de astrágalo abierta: Evolución a medio plazo Medial dislocation of the talus: Medium term evolution

    Directory of Open Access Journals (Sweden)

    S. García Mata

    2009-04-01

    Full Text Available Paciente de 57 años con enucleación abierta medial del astrágalo izquierdo, con fractura suprasindesmal de peroné, por traumatismo indirecto. Se realizó lavado, limpieza del astrágalo y partes blandas, Friedrich, reducción, fijación con agujas de kirschner, sutura del ligamento deltoideo y osteosíntesis del peroné. No hubo infección superficial ni profunda postoperatoria. Permaneció seis semanas de inmovilización y tres meses en descarga. Dos años después no había signos radiológicos de necrosis avascular. En gammagrafía ósea realizada a los 18 meses de la lesión se observaba necrosis avascular parcial astragalina. Tres años después de la lesión realizaba vida normal, sin dolor en reposo pero sí a la marcha y movilidad con limitación de la dorsiflexión (-20º. Cinco años y medio después de la lesión presentaba hundimiento de cúpula astragalina por la necrosis avascular con sintomatología dolorosa a la marcha y diástasis tibio-peronea distal, que requirió realizar artrodesis tibio-astragalina.Fifty-seven year old patient with open medial dislocation of the left talus, with suprasyndesmotic fracture of the fibula, due to indirect traumatism. The following were carried out: washing, cleaning the talus and the soft parts, Friedrich, reduction, fixing with Kirschner needles, suture of the deltoid ligament, and osteosynthesis of the fibula. There were neither surface nor deep post-operational infections. The patient underwent six weeks of immobilisation and spent three months on discharge. Two years later there were no radiological signs of avascular necrosis. In the osseous gammagraphy carried out 18 months after the lesion, partial avascular necrosis of the talus was observed. Three years after the lesion, the patient was able to carry out a normal life, without pain in repose but with pain whilst moving, and mobility with limitation of dorsoinflection (-20º. Five and a half years after the lesion, the patient presented sinking of the talar dome due to avascular necrosis, with painful symptomatology whilst moving, and tibiofibular distal diastasis, which required ankle arthrodesis.

  14. Enucleación medial de astrágalo abierta: Evolución a medio plazo / Medial dislocation of the talus: Medium term evolution

    Scientific Electronic Library Online (English)

    S., García Mata; A., Hidalgo Ovejero; F., Martínez de Lecea.

    2009-04-01

    Full Text Available Paciente de 57 años con enucleación abierta medial del astrágalo izquierdo, con fractura suprasindesmal de peroné, por traumatismo indirecto. Se realizó lavado, limpieza del astrágalo y partes blandas, Friedrich, reducción, fijación con agujas de kirschner, sutura del ligamento deltoideo y osteosínt [...] esis del peroné. No hubo infección superficial ni profunda postoperatoria. Permaneció seis semanas de inmovilización y tres meses en descarga. Dos años después no había signos radiológicos de necrosis avascular. En gammagrafía ósea realizada a los 18 meses de la lesión se observaba necrosis avascular parcial astragalina. Tres años después de la lesión realizaba vida normal, sin dolor en reposo pero sí a la marcha y movilidad con limitación de la dorsiflexión (-20º). Cinco años y medio después de la lesión presentaba hundimiento de cúpula astragalina por la necrosis avascular con sintomatología dolorosa a la marcha y diástasis tibio-peronea distal, que requirió realizar artrodesis tibio-astragalina. Abstract in english Fifty-seven year old patient with open medial dislocation of the left talus, with suprasyndesmotic fracture of the fibula, due to indirect traumatism. The following were carried out: washing, cleaning the talus and the soft parts, Friedrich, reduction, fixing with Kirschner needles, suture of the de [...] ltoid ligament, and osteosynthesis of the fibula. There were neither surface nor deep post-operational infections. The patient underwent six weeks of immobilisation and spent three months on discharge. Two years later there were no radiological signs of avascular necrosis. In the osseous gammagraphy carried out 18 months after the lesion, partial avascular necrosis of the talus was observed. Three years after the lesion, the patient was able to carry out a normal life, without pain in repose but with pain whilst moving, and mobility with limitation of dorsoinflection (-20º). Five and a half years after the lesion, the patient presented sinking of the talar dome due to avascular necrosis, with painful symptomatology whilst moving, and tibiofibular distal diastasis, which required ankle arthrodesis.

  15. Terra Sirenum Slope

    Science.gov (United States)

    2004-01-01

    16 July 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the layered rocks and boulders exposed on the wall of a trough in the Terra Sirenum region. The layers that erode to produce large boulders are harder and more resistant to weathering and erosion than those that do not. The slope is located near 25.8oS, 139.8oW. The image covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the upper left.

  16. Functional anatomy of the calcaneum and talus in Cercopithecinae (Mammalia, Primates, Cercopithecidae

    Directory of Open Access Journals (Sweden)

    Pina, M.

    2011-12-01

    Full Text Available Among the species of the order Primates exist a huge variety of forms and habitats. This heterogeneity has encouraged the evolution and development of a great number of locomotor adaptations to different environments. Thus, nowadays there are both arboreal and terrestrial groups within the order. The subfamily Cercopithecinae present taxa with both kinds of locomotor behaviours, although the most of them are adapted to a ground life-style. This group probably has an arboreal ancestor and its radiation is relatively recent. Consequently, species belonged to this group present mixed features or sometimes not too much derived ones. Likewise, it is important the fact that the evolutionary history and phylogeny of the group could influence in some characteristics. Both the calcaneum and the talus are two of the largest bones of the foot and are good for inferring the kind of locomotion. For this reason, it has been used these two tarsal bones to study the morphology of eight species of cercopithecines and then deduce functional implications of the kind of locomotion.

    Dentro del orden Primates existe una gran variedad de especies distribuidas a lo largo de hábitats muy diversos. Dicha heterogeneidad ha fomentado la evolución y desarrollo de un gran número de adaptaciones locomotoras a los diferentes ambientes en los que habitan. Así, existen en la actualidad tanto grupos arborícolas como terrestres. La subfamilia Cercopithecinae agrupa una serie de taxones que representan ambos comportamientos locomotores, aunque la mayoría de las especies están adaptadas a una vida en el suelo. Se supone que este grupo desciende de un ancestro arborícola y que su radiación es relativamente reciente. En consecuencia, las especies de este grupo presentan características mixtas o poco derivadas en algunas ocasiones. Asimismo, es importante tener en cuenta la influencia que la herencia filogenética puede tener sobre alguno de estos rasgos. El calcáneo y el astrágalo son dos de los huesos más grandes del pie y ambos son buenos indicadores del tipo de locomoción. Por este motivo, se han utilizado estos dos tarsales para llevar a cabo el estudio de la morfología de ocho especies de cercopitecoideos, de tal manera que luego se ha podido hacer una serie de inferencias funcionales en cuanto al tipo de locomocón de las mismas.

  17. Osteochondral lesions of the talus in a sports medicine clinic. A new radiographic technique and surgical approach.

    Science.gov (United States)

    Thompson, J P; Loomer, R L

    1984-01-01

    A retrospective review of 11 patients seen at the University of British Columbia Sports Medicine Clinic with osteochondral lesions of the talus was undertaken. From our data, a number of points became apparent. There was a predominance of posteromedial talar dome lesions. A flexion-inversion ankle injury could be documented in the majority of cases. There was frequently a long delay in diagnosing these ankle sprain mimics. Historical details which should raise one's index of suspicion include: (1) history of flexion-inversion injury; (2) exercise-related ankle pain; (3) sensations of "clicking and catching"; and (4) persistent swelling. Surgery produced consistently good early results in these active patients without osteotomizing the medial malleolus. Experimental analysis and clinical experience suggest that the optimal radiographic technique for identifying the posteromedial osteochondral lesion consists of an anteroposterior view of the ankle in maximum plantar flexion with the kilovoltage set at 70. PMID:6507717

  18. Interior Slopes of Copernican Craters

    Science.gov (United States)

    Robinson, M. S.; Burns, K.; Stelling, R.; Speyerer, E.; Mahanti, P.

    2012-12-01

    The Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) routinely acquires high resolution (50 to 200 cm pixel scales) stereo pairs from adjacent orbits through spacecraft slews; parallax angles are typically >20°, and the local incidence angle between 40° and 65°. These observations are reduced to digital elevation models (DEM) using a combination of ISIS (USGS) and SOCET Set (BAE Systems). For this study DEMs originally sampled at 2 m scales were reduced (averaging technique) to 5 m scales to provide slopes calculated over 3x3 pixel boxes (15 m x 15 m). The upper 50% of interior walls of Copernican craters (2 to 20 km diameter) typically have average slopes of 36°, with slopes locally above 40° not uncommon (i.e. Fig 1: 2.3 km diam, 17.68°S, 144.41°E). Giordano Bruno (GB; 35.97N°, 102.86°E) is likely the youngest 20-km diameter class crater on the Moon. Its floor is dominated by impact forms (ponds and flows), and inner walls exhibit a series of coalesced flow lobes emanating from steep upper slopes. The lobes appear to be composed of dry granular material based on the observation of boulder trails superposed on many examples. The upper slopes average 36° or more, with some slopes above 40°. For much of GB, slopes exceed 30° all the way to the crater floor (especially in the SE). The high slopes imply angular grains, some level of cohesion, and/or higher angles of repose due to the Moon's relatively low gravity. Larmor Q (28.56°N, 176.33°E), another large Copernican crater, is elliptical in plan (23 x 18 km diameter), with an interior floor dominated by large slump blocks. Like GB its walls exhibit overlapping lobes (granular materials) emanating from interior wall slopes that range from 30° to 36°. Other Copernican craters exhibit similar steep slopes on interior walls: Moore F (23 km diam), Necho (30 km), and two unnamed craters (9 km,13.31°S, 257.55°E; 9 km, 15.72°, 177.39°E). Slopes of the central peaks of Tycho crater (0.1 by age) are equally steep (24° to 36°). The central peaks of Tsiolkovskiy crater (>3.0 by age) have slopes significantly shallower (20°) than younger counterparts, likely due to eons of micrometorite bombardment. High resolution (2-5 m pixel scales) LROC NAC topographic maps of impact craters are enabling characterization of slopes across a broad population of fresh and degraded craters; key information for improving numeric models of crater formation and subsequent erosion processes.

  19. A mounded spherical storage tank at Papeete; Une sphere sous talus a Papeete

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2003-09-01

    Because demand for liquid petroleum gas (LPG) in French Polynesia is burgeoning, deliveries of the product are on the rise, in particular from New Zealand. In consideration of this, Gaz de Tahiti has had a mounded 1.800 m{sup 3} spherical propane storage tank built by the Tissot group. The new tank joins the ranks of the standard 2.500 m{sup 3} spherical butane tank that Gaz de Tahiti already has at its Papeete site. The slope consists of earth-filled gabions, which are at least one metre thick at any point of the steel structure. The project is proof once again that Gaz de Tahiti has no reason to envy European companies when it comes to technology and development. (authors)

  20. MORPHOMETRY OF THE ARTICULAR FACETS ON THE SUPERIOR, MEDIAL AND LATERAL SURFACES OF THE BODY OF TALUS AND ITS CLINICAL RELEVANCE

    Directory of Open Access Journals (Sweden)

    Goda Jatin B, Patel Shailesh M, Parmar Ajay M, Agarwal GC

    2015-07-01

    Full Text Available Background: In the formation of Ankle joint, tibio-fibular mortice receives superior, medial and lateral articular surfaces of body of Talus. Because of very limited availability of the data on the Morphometry of the articular facets on the Body of the dry human tali, this study was undertaken. Aims: To prepare the database on the articular facets on the superior, medial and lateral surfaces of body of talus, to find if there is statistically significant difference between both the sides of measurements and to compare the results with the previous studies. Methods and Material: 40 Dry Human Tali (20 Right and 20 Left were measured with Digital vernier caliper for the following Measurements: On the Trochlear surface: Medial length, Central length, Lateral length, Anterior width, Central width, Posterior width. On the lateral triangular articular facet: Central height, Central width. On the coma shaped medial articular facet: Central height, Central width. Results: Mean values of Medial, Central and Lateral lengths were 31.02, 30.39 and 29.63mm on Right side and 31.79, 30.65 and 29.45mm on Left side. Mean Anterior, Central and Posterior widths were 28.87, 28.16 and 21.59mm on right side and 29.08, 27.54 and 21.78mm on left side. On the medial articular surface, mean central height was 11.93mm on the right side and 11.29mm on the left side, Mean central width was 27.94mm on the right side and 28.29mm on the left side. On the lateral articular surface, mean central height was 22.14mm on the right side and 22.63mm on the left side. Mean central width was 18.93mm on the right side and 18.99mm on the left side. There is no significant difference between right and left sides of measurements. Conclusion: The trochlear articular surface is wider in front, measurements of opposite talus bone can be used as a control during talus bone replacement surgery, it may help surgeons to plan pre-operatively the complex talar fracture surgeries, to design accurate talus bone prosthesis and talus implants.

  1. Probabalistic analysis of slope stability

    OpenAIRE

    Jakši?, Miha

    2006-01-01

    In my graduation thesis I studied analysis of slope stability. Civil engineers predominantly use deterministic methods, however there are better ways to determine slope stability. The focus of my work was probabilistic analysis. I examined advantages and weaknesses of probabilistic analysis. My goal was to determine how different methods and assumptions affect the credibility of results. The tests were carried out by computer program which performs numerical simulations of given models of slo...

  2. North Slope (Wahluke Slope) expedited response action cleanup plan

    International Nuclear Information System (INIS)

    The purpose of this action is to mitigate any threat to public health and the environment from hazards on the North Slope and meet the expedited response action (ERA) objective of cleanup to a degree requiring no further action. The ERA may be the final remediation of the 100-I-3 Operable Unit. A No Action record of decision (ROD) may be issued after remediation completion. The US Department of Energy (DOE) currently owns or administers approximately 140 mi2 (about 90,000 acres) of land north and east of the Columbia River (referred to as the North Slope) that is part of the Hanford Site. The North Slope, also commonly known as the Wahluke Slope, was not used for plutonium production or support facilities; it was used for military air defense of the Hanford Site and vicinity. The North Slope contained seven antiaircraft gun emplacements and three Nike-Ajax missile positions. These military positions were vacated in 1960--1961 as the defense requirements at Hanford changed. They were demolished in 1974. Prior to government control in 1943, the North Slope was homesteaded. Since the initiation of this ERA in the summer of 1992, DOE signed the modified Hanford Federal Agreement and Consent Order (Tri-Party Agreement) with the Washington Department of Ecology (Ecology) and the US Environmental Protection Agency (EPA), in which a milestone was set to complete remediation activities and a draft closeout report by October 1994. Remediation activities will make the North Slope area available for future non-DOE uses. Thirty-nine sites have undergone limited characterization to determine if significant environmental hazards exist. This plan documents the results of that characterization and evaluates the potential remediation alternatives

  3. North Slope (Wahluke Slope) expedited response action cleanup plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    The purpose of this action is to mitigate any threat to public health and the environment from hazards on the North Slope and meet the expedited response action (ERA) objective of cleanup to a degree requiring no further action. The ERA may be the final remediation of the 100-I-3 Operable Unit. A No Action record of decision (ROD) may be issued after remediation completion. The US Department of Energy (DOE) currently owns or administers approximately 140 mi{sup 2} (about 90,000 acres) of land north and east of the Columbia River (referred to as the North Slope) that is part of the Hanford Site. The North Slope, also commonly known as the Wahluke Slope, was not used for plutonium production or support facilities; it was used for military air defense of the Hanford Site and vicinity. The North Slope contained seven antiaircraft gun emplacements and three Nike-Ajax missile positions. These military positions were vacated in 1960--1961 as the defense requirements at Hanford changed. They were demolished in 1974. Prior to government control in 1943, the North Slope was homesteaded. Since the initiation of this ERA in the summer of 1992, DOE signed the modified Hanford Federal Agreement and Consent Order (Tri-Party Agreement) with the Washington Department of Ecology (Ecology) and the US Environmental Protection Agency (EPA), in which a milestone was set to complete remediation activities and a draft closeout report by October 1994. Remediation activities will make the North Slope area available for future non-DOE uses. Thirty-nine sites have undergone limited characterization to determine if significant environmental hazards exist. This plan documents the results of that characterization and evaluates the potential remediation alternatives.

  4. Did talus-derived rock glaciers and cirque glaciers co-exist during MIS 3 and 2 in coastal northern Norway?

    Science.gov (United States)

    Linge, H.; Dahl, S.

    2012-12-01

    Evidence of past activity of talus-derived rock glaciers and cirque glaciers, nearly down to the present-day sea level in northern Norway, can be taken as proof of extreme climate in the past. The geology of Andøya (69 N 16 E) has been explored for a long time, and suites of onshore and offshore landforms have been investigated in order to reveal the ice age history. The continental shelf is less than 15 km wide off northwestern Andøya, and the current knowledge of the LGM ice margin position at Andøya suggests that perhaps the Ålesund (38.5-34.5 ka) and Austnes (44-42 ka) Interstadials should be present in the (morpho-) stratigraphic record. Pinpointing the time of landform formation and/or stagnation (inactivation) can provide details of past local or regional patterns of temperature, precipitation and prevailing wind directions. Crucial in this context is the ability to precisely date the landforms, and to understand what phase (if any) of the landform's history the date reflects (e.g. inception, inactivation, stabilisation). This study has investigated the temporal relationship between activity of cirque glaciers and talus-derived rock glaciers on northern Andøya using cosmogenic 10Be surface exposure dating. If active at the same time, talus-derived rock glaciers and cirque glaciers must reflect a delicate balance in the local climate between temperature, precipitation and wind direction, allowing both types to co-exist. If active at different times, talus-derived rock glaciers and cirque glaciers in the same region could reflect shifting climatic conditions (temperature, precipitation, wind direction). Ages of these landforms could provide valuable palaeoclimate information prior to the 'onset' of biogenic production and/or older than the time range of radiocarbon dating.

  5. Root tensile strength relationships and their slope stability implications of three shrub species in the Northern Apennines (Italy)

    Science.gov (United States)

    Tosi, Matteo

    2007-07-01

    The role of root strength is important in stabilising steep hillslopes which are seasonally affected by storm-induced shallow landslides. In the Italian Apennines, steep (25-40°) slopes underlain by mudstone are generally stable if they are covered by shrubs whose roots anchor into the soil mantle. To quantify the mechanical reinforcement of roots to soil, the root tensile breaking force and the root tensile strength of three autochthonous shrub species commonly growing on stiff clay soils of the Northern Italian Apennines, Rosa canina (L.), Inula viscosa (L.) and Spartium junceum (L.), were measured by means of field and laboratory tests. For each test approximately 150 root specimens were used. The tensile force increases with increasing root diameter following a second-order polynomial regression curve. The tensile strength decreases with increasing root diameter following a power law curve. The field in situ tensile force required to break a root is always smaller than that obtained from laboratory tests for the same root diameter, although their difference becomes negligible if the root diameter is smaller than 5 mm. The influence of root tensile strength on soil shear strength was verified based on the infinite slope stability model. The root reinforcement was calculated using the number and mean diameter of roots. The factor of safety was calculated for three different soil thickness values (0.1, 0.3, and 0.6 m) and topographic slopes between 10° and 45°. The factor of safety for the combination of 0.6 m soil thickness, slopes smaller than 30°, and vegetation of I. viscosa (L.) or S. junceum (L.) is always larger than 1. If a slope is steeper, the factor of safety may be smaller than 1 for I. viscosa (L.), although it is still larger than 1 for S. junceum (L.). In the stiff clayey areas of the Northern Italian Apennines, I. viscosa (L.) mainly colonizes fan/cone/taluses and stabilises these zones up to a topographic gradient < 30° for a soil 0.6 m thick. S. junceum (L.) colonizes not only fan/cone/taluses but also headwalls and cliffs and, for a 0.6 m thick soil, it stabilises these areas up to 45°. The effectiveness of this reinforcement, however, depends strongly on the frequency of soil and seasonal grass vegetation removal due to shallow landsliding before the entrance of the shrub species.

  6. All-Arthroscopic Autologous Matrix-Induced Chondrogenesis for the Treatment of Osteochondral Lesions of the Talus.

    Science.gov (United States)

    Usuelli, Federico Giuseppe; de Girolamo, Laura; Grassi, Miriam; D'Ambrosi, Riccardo; Montrasio, Umberto Alfieri; Boga, Michele

    2015-06-01

    Several surgical techniques have been described for the treatment of talar chondral lesions. Among them, microfracture is well established. Autologous matrix-induced chondrogenesis (AMIC), using microfracture and biomaterials, has shown promising results for the treatment of knee osteochondral lesions and has been proposed for the ankle as an open technique. We describe an all-arthroscopic AMIC technique. The benefits of an all-arthroscopic procedure include smaller incisions with less soft-tissue dissection, better visualization of the joint, and a quicker recovery compared with open surgery. The use of matrix to support cartilage regeneration promotes good-quality cartilage tissue with satisfactory long-term outcomes. Our all-arthroscopic AMIC technique uses a type I-type III porcine collagen matrix (Chondro-Gide; Geistlich Pharma, Wolhusen, Switzerland) and is characterized by 2 different arthroscopic surgical phases. First, adequate exposure is achieved through use of a Hintermann spreader (Integra LifeSciences, Plainsboro, NJ) with sufficient joint distraction and wet lesion preparation. The second surgical step is performed dry, involving matrix placement and fixation. The all-arthroscopic AMIC technique for the treatment of osteochondral lesions of the talus allows a very precise reconstruction in the case of cartilage defects and avoids the need for a more invasive operation associated with higher morbidity and a longer surgical time. PMID:26258040

  7. Anatomy of gravitationally deformed slopes

    Science.gov (United States)

    Chigira, Masahiro; Yamasaki, Shintaro; Hariyama, Takehiro

    2010-05-01

    Deep-seated gravitational slope deformation is the deformation of rocks as well as slope surfaces, but the internal structures have not been well observed and described before. This is mainly due to the difficulty in obtaining undisturbed samples from underground. We analyzed the internal deformational structures of gravitationally deformed slopes by using high quality drilled cores obtained by hybrid drilling technique, which has been recently developed and can recover very fragile materials that could not be taken by the conventional drilling techniques. Investigated slopes were gravitationally deformed out-facing slopes of pelitic schist and shale. The slope surfaces showed deformational features of small steps, depressions, knobs, and linear depressions, but had no major main scarp and landslide body with well-defined outline. This is indicative of slow, deep-seated gravitational deformation. Most of these small deformational features are hidden by vegetations, but they are detected by using airborne laser scanner. Drilled cores showed that the internal deformation is dominated by the slip and tearing off along foliations. Slippage along foliations is conspicuous in pelitic schist: Pelitic schist is sheared, particularly along black layers, which are rich in graphite and pyrite. Graphite is known to be a solid lubricant in material sciences, which seems to be why shearing occurs along the black layers. Rock mass between two slip layers is sheared, rotated, fractured, and pulverized; undulation of bedding or schistosity could be the nucleation points of fracturing. Tearing off along foliations is also the major deformation mode, which forms jagged morphology of rock fragments within shear zones. Rock fragments with jagged surface are commonly observed in "gouge", which is very different from tectonic gouge. This probably reflects the low confining pressures during their formation. Microscopic to mesoscopic openings along fractures are commonly observed with fractures, which also suggests the low confining pressures. Vertical distribution of gravitational deformation with above features indicates that gravitational shear zones are nucleated in a distributed manner, then gradually connected to each other, and finally cut through the whole slope. This is the transition of gravitational mass rock creep to rock slide. First nucleation points seem to be controlled by the heterogeneity of rock properties. Thick black layers in pelitic schist, shale near thick sandstone beds in sedimentary rocks, were such nuclear points. The geometrical relationships between the distribution of fracture zones and the slope morphology suggest that they are formed in accordance to the valley incision and resultant slope destabilization.

  8. Radioecological reliability of slope ecosystem

    International Nuclear Information System (INIS)

    Natural and technogenic cataclysms taking place in Ukraine bring to the forefront the problem of estimation and forecast of different ecosystems type. Theory and models of the radio capacity and reliability developed by us allow to describe adequately regularities of radionuclide migration and redistribution in slope ecosystems, and carry out mathematical modeling of investigated phenomena. That will give the possibility to use special countermeasures

  9. Arthroscopic Excision of Bone Fragments in a Neglected Fracture of the Lateral Process of the Talus in a Junior Soccer Player

    OpenAIRE

    Funasaki, Hiroki; Kato, Soki; Hayashi, Hiroteru; Marumo, Keishi

    2014-01-01

    Fractures of the lateral process of the talus are uncommon and often overlooked. Typically, they are found in adult snowboarders. We report the case of an 11-year-old male soccer player who complained of lateral ankle pain after an inversion injury 6 months earlier. He did not respond to conservative treatment and thus underwent arthroscopic excision of fragments of the talar lateral process. The ankle was approached through standard medial and anterolateral portals. A 2.7-mm-diameter 30° art...

  10. Slope Streaks in Terra Sabaea

    Science.gov (United States)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1 Click on image for larger version This HiRISE image shows the rim of a crater in the region of Terra Sabaea in the northern hemisphere of Mars. The subimage (figure 1) is a close-up view of the crater rim revealing dark and light-toned slope streaks. Slope streak formation is among the few known processes currently active on Mars. While their mechanism of formation and triggering is debated, they are most commonly believed to form by downslope movement of extremely dry sand or very fine-grained dust in an almost fluidlike manner (analogous to a terrestrial snow avalanche) exposing darker underlying material. Other ideas include the triggering of slope streak formation by possible concentrations of near-surface ice or scouring of the surface by running water from aquifers intercepting slope faces, spring discharge (perhaps brines), and/or hydrothermal activity. Several of the slope streaks in the subimage, particularly the three longest darker streaks, show evidence that downslope movement is being diverted around obstacles such as large boulders. Several streaks also appear to originate at boulders or clumps of rocky material. In general, the slope streaks do not have large deposits of displaced material at their downslope ends and do not run out onto the crater floor suggesting that they have little reserve kinetic energy. The darkest slope streaks are youngest and can be seen to cross cut and superpose older and lighter-toned streaks. The lighter-toned streaks are believed to be dark streaks that have lightened with time as new dust is deposited on their surface. Observation Geometry Image PSP_001808_1875 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 15-Dec-2006. The complete image is centered at 7.4 degrees latitude, 47.0 degrees East longitude. The range to the target site was 272.1 km (170.1 miles). At this distance the image scale is 54.4 cm/pixel (with 2 x 2 binning) so objects 163 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel and north is up. The image was taken at a local Mars time of 03:36 PM and the scene is illuminated from the west with a solar incidence angle of 53 degrees, thus the sun was about 37 degrees above the horizon. At a solar longitude of 150.7 degrees, the season on Mars is Northern Summer. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

  11. Gravity-induced stresses in finite slopes

    Science.gov (United States)

    Savage, W.Z.

    1994-01-01

    An exact solution for gravity-induced stresses in finite elastic slopes is presented. This solution, which is applied for gravity-induced stresses in 15, 30, 45 and 90?? finite slopes, has application in pit-slope design, compares favorably with published finite element results for this problem and satisfies the conditions that shear and normal stresses vanish on the ground surface. The solution predicts that horizontal stresses are compressive along the top of the slopes (zero in the case of the 90?? slope) and tensile away from the bottom of the slopes, effects which are caused by downward movement and near-surface horizontal extension in front of the slope in response to gravity loading caused by the additional material associated with the finite slope. ?? 1994.

  12. Slope Stability Analysis Using Numerical Method

    OpenAIRE

    Jasim M Abbas

    2014-01-01

    Stability evaluations are regularly achieved in order to measure the safe and efficient design of man-made slope (e.g., open pit mining, road cuts, etc.,) and/or the stability conditions of a natural slope. It has been issue of concern to numerous previous investigators. The numerical technique chosen depends on both soil specifications and its situations and the potential mode of failure. Assessment has been made for slope system with different slope for both cohesive and cohesionless soil. ...

  13. Geotechnical system reliability of slopes

    International Nuclear Information System (INIS)

    In slope stability analysis it is customary to search for the critical slip surface considering the conventional factor of safety as an index of stability. With the development of reliability analysis approaches within a probabilistic framework, alternative definitions of the critical slip surface can be adopted. Thus one may define a critical slip surface as one with the lowest reliability index or one with the highest probability of failure. However, it is important to consider the slope stability problem in terms of a system of many potential slip surfaces. For such a system, the calculation of system reliability is appropriate and desirable. In this paper, system reliability bounds are calculated within a probabilistic framework. The 'system reliability' or the 'system probability of failure' must be estimated for comparison with the corresponding reliability or probability of failure with respect to a 'critical' slip surface. The general slope stability problem involving non-zero internal friction angle involves a non-linear performance function. Moreover, the expression for factor of safety is usually inexplicit except for the ordinary method of slices which is not accurate except when 'oe = 0'. This paper addresses the system reliability for inexplicit and non-linear performance functions as well as for linear and explicit ones. Any version of the method of slices may be used although the proposed approach is presented on the basis of the Bishop simplified method. It is shown that the upper bound system failure probability is higher than the failure probability associated with a critical slip surface. The difference increases as the coefficient of variation of the shear strength parameters increases

  14. Kuhse, Singer and slippery slopes.

    Science.gov (United States)

    Fairbairn, G J

    1988-01-01

    Helga Kuhse and Peter Singer recently examined the view expressed by John Lorber that whereas at times it is permissible to allow severely handicapped infants to die, killing them must never be allowed. In attempting to demonstrate the mistaken nature of Lorber's fear that allowing active infanticide would lead us onto a slippery slope Kuhse and Singer make much use of John Harris's paper in the Journal of Medical Ethics in which he criticised Lorber's views. This paper examines some aspects of the case advanced by Kuhse and Singer and of the earlier paper by Harris. PMID:2972837

  15. A simple limit for slope instability

    OpenAIRE

    J. Stoppa; Tenni, E.

    2009-01-01

    Ross and Thomas have shown that subschemes can K-destabilise polarised varieties, yielding a notion known as slope (in)stability for varieties. Here we describe a special situation in which slope instability for varieties (for example of general type) corresponds to a slope instability type condition for certain bundles, making the computations almost trivial.

  16. Delayed gadolinium-enhanced MRI of cartilage of the ankle joint: Results after autologous matrix-induced chondrogenesis (AMIC)-aided reconstruction of osteochondral lesions of the talus

    International Nuclear Information System (INIS)

    Aim: To assess cartilage quality using delayed gadolinium-enhanced magnetic resonance imaging after repair of osteochondral lesions of the talus using autologous matrix-induced chondrogenesis (AMIC). Materials and methods: A three-dimensional (3D) spoiled gradient-echo (SGE) sequence at 3 T was used to obtain quantitative T1 relaxation times before and after Gd-DTPA2 (Magnevist, 0.2 mM/kg bod weight) administration to assess 23 cases of AMIC-aided repair of osteochondral lesions of the talus. Delta relaxation rates (?R1) for reference cartilage (RC) and repair tissue (RT), and the relative delta relaxation rate (r?R1) were calculated. The morphological appearance of the cartilage RT was graded on sagittal dual-echo steady-state (DESS) views according to the “magnetic resonance observation of cartilage repair tissue” (MOCART) protocol. The study was approved by the institutional review board and written consent from each patient was obtained. Results: The AMIC cases had a mean T1 relaxation time of 1.194 s (SD 0.207 s) in RC and 1.470 s (SD 0.384 s) in RT before contrast medium administration. The contrast-enhanced T1 relaxation time decreased to 0.480 s (SD 0.114 s) in RC and 0.411 s (SD 0.096 s) in RT. There was a significant difference (p > 0.05) between the ?R1 in RC (1.372 × 10?3/s, range 0.526–3.201 × 10?3/s, SD 0.666 × 10?3/s) and RT (1.856 × 10?3/s, range 0.93–3.336 × 10?3/s, SD 0.609 × 10?3/s). The mean r?R1 was 1.49, SD 0.45). The mean MOCART score at follow-up was 62.6 points (range 30–95, SD 15.3). Conclusion: The results of the present study suggest that repair cartilage resulting from AMIC-aided repair of osteochondral lesions of the talus has a significantly lower glycosaminoglycan (GAG) content than normal hyaline cartilage, but can be regarded as having hyaline-like properties

  17. Construction of embankments with steep slopes

    OpenAIRE

    ?ulsi?, Adnan

    2010-01-01

    The subject of this degree is different methods for construction of steep slopes. For long-term stability and usefulness of the steep slopes it is necessary to provide additional support forces to ensure safe construction and use of banks. For the safe construction and use of steep slopes, I presented four possible variants of the retaining structures. I considered two types of gravity retaining structures and retaining structures that rely on the reinforcement of soil. The stu...

  18. Error Reduction in Slope Stability Assessment

    OpenAIRE

    Fleurisson, Jean-Alain; Roger COJEAN

    2014-01-01

    Slopes in quarries and open pit mines, as well as all the types of embankments (stockpiles, tailing dams, waste dumps) resulting from mining and mineral processing activities, must be considered as "geotechnical structures". Therefore, the design and implementation of these structures must be conducted with all consideration.The main aim of this chapter is to highlight the basic principles of the slope design process, to review the methods of stability analysis and slope design, as well as th...

  19. Analysis of Slope Stability Using Limit Equilibrium

    OpenAIRE

    Abdoullah Namdar,

    2010-01-01

    In achievement of slope load sustainability using mixed soil technique, is considered acceptable the method for slope construction technology. This paper deals with evaluation of mixed soil technique for construction of stable slope and proves the soil capability by analysis of computerized modeling, the revealed result of investigation, the possibility of using nearest local material, reducing project cost, solving the construction geotechnical problem and accurate understanding of soil prop...

  20. Air pocket removal from downward sloping pipes:

    OpenAIRE

    I. W. M. Pothof; Clemens, F.H.L.R.

    2012-01-01

    Air-water flow is an undesired condition in water pipelines and hydropower tunnels. Water pipelines and wastewater pressure mains in particular are subject to air pocket accumulation in downward sloping reaches, such as inverted siphons or terrain slopes. Air pockets cause energy losses and an associated capacity reduction. Despite its practical relevance, many phenomena associated with airwater flow in downward sloping pipe reaches are still poorly understood. Deltares and Delft University o...

  1. Precision of SPECT/CT allows the diagnosis of a hidden Brodie's abscess of the talus in a patient with sickle cell disease

    International Nuclear Information System (INIS)

    Brodie's abscess is a rare subacute osteomyelitis that can be found in sickle cell disease along with other bone complications. A 21-year-old female with sickle cell disease was presenting frequently to the medical casualty department for painful vasoocclusive crises and for persistent ankle pain and swelling. Hybrid imaging with single-photon emission computed tomography-computed tomography (SPECT-CT) incidentally revealed Brodie's abscess in the talus bone of the ankle, causing persisting long-standing pain. SPECT-CT is a modern technology used to scan bone to detect both anatomical and functional abnormalities with high specificity. Brodie's abscess is a rare bone inflammation that could be a hidden cause of pain and infection in sickle cell disease. Although rare, this lesion requires more attention in patients with sickle cell disease because their immunocompromised status renders them prone to this infection

  2. Precision of SPECT/CT allows the diagnosis of a hidden Brodie's abscess of the talus in a patient with sickle cell disease

    Energy Technology Data Exchange (ETDEWEB)

    Al jafar, Hassan [Dept. of Hematology, Amiri Hospital, Kuwait (Kuwait); Al Shemmeri, Eman [Dept. of Nuclear Medicine, Farwaniya Hospital, Al-Farwania (Kuwait); Al Shemmeri, Jehan; Al Enizi, Saud [Faculty of Medicine, Nuclear Medicine Dept, Kuwait University, Kuwait (Kuwait); Aytglu, Leena [Molecular Imaging Center, Jaber Al-Ahmad Center, Kuwait (Kuwait); Afzai, Uzma [Dept. of Nuclear Medicine, Farwaniya Hospital, Al-Farwania (Kuwait)

    2015-06-15

    Brodie's abscess is a rare subacute osteomyelitis that can be found in sickle cell disease along with other bone complications. A 21-year-old female with sickle cell disease was presenting frequently to the medical casualty department for painful vasoocclusive crises and for persistent ankle pain and swelling. Hybrid imaging with single-photon emission computed tomography-computed tomography (SPECT-CT) incidentally revealed Brodie's abscess in the talus bone of the ankle, causing persisting long-standing pain. SPECT-CT is a modern technology used to scan bone to detect both anatomical and functional abnormalities with high specificity. Brodie's abscess is a rare bone inflammation that could be a hidden cause of pain and infection in sickle cell disease. Although rare, this lesion requires more attention in patients with sickle cell disease because their immunocompromised status renders them prone to this infection.

  3. Slope Estimation from ICESat/GLAS

    Directory of Open Access Journals (Sweden)

    Craig Mahoney

    2014-10-01

    Full Text Available We present a novel technique to infer ground slope angle from waveform LiDAR, known as the independent slope method (ISM. The technique is applied to large footprint waveforms (\\(\\sim\\ mean diameter from the Ice, Cloud and Land Elevation Satellite (ICESat Geoscience Laser Altimeter System (GLAS to produce a slope dataset of near-global coverage at \\(0.5^{\\circ} \\times 0.5^{\\circ}\\ resolution. ISM slope estimates are compared against high resolution airborne LiDAR slope measurements for nine sites across three continents. ISM slope estimates compare better with the aircraft data (R\\(^{2}=0.87\\ and RMSE\\(=5.16^{\\circ}\\ than the Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM inferred slopes (R\\(^{2}=0.71\\ and RMSE\\(=8.69^{\\circ}\\ ISM slope estimates are concurrent with GLAS waveforms and can be used to correct biophysical parameters, such as tree height and biomass. They can also be fused with other DEMs, such as SRTM, to improve slope estimates.

  4. Tibiocalcaneal Arthrodesis With a Porous Tantalum Spacer and Locked Intramedullary Nail for Post-Traumatic Global Avascular Necrosis of the Talus.

    Science.gov (United States)

    Cohen, Michael M; Kazak, Marat

    2015-01-01

    Global avascular necrosis of the talus is a devastating complication that usually occurs as a result of a post-traumatic or metabolic etiology. When conservative options fail, tibiocalcaneal arthrodesis is generally indicated in conjunction with massive bone grafting to maintain the functional length of the extremity. Several bone grafting options are available, including the use of a freeze-dried or fresh-frozen femoral head allograft or autograft obtained from the iliac crest or fibula, all of which pose their own inherent risks. The noted complications with massive bone grafting techniques have included graft collapse, infection, immune response, donor site morbidity, and nonunion. In an effort to avoid many of these complications, we present a case report involving post-traumatic talar avascular necrosis in a 59-year-old male who was successfully treated with the use of a porous tantalum spacer, an autogenic morselized fibular bone graft, and 30 mL of bone marrow aspirate in conjunction with a retrograde tibiocalcaneal nail. Porous tantalum is an attractive substitute for bone grafting because of its structural integrity, biocompatibility, avoidance of donor site complications, and lack of an immune response. The successful use of porous tantalum has been well-documented in hip and knee surgery. We present a practical surgical approach to tibiotalocalcaneal arthrodesis with a large segmental deficit. To our knowledge, this is the first published report describing an alternative surgical technique to address global avascular necrosis of the talus that could have additional applications in salvaging the ankle with a large bone deficiency. PMID:26002681

  5. Slope of the Slope Derivative Surface used to characterize the complexity of the seafloor around St. John, USVI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Slope of slope was calculated from the bathymetry surface for each raster cell by applying the ArcGIS Spatial Analyst 'Slope' Tool to a previously created slope...

  6. Slope factor and shallow landslide occurrence

    Science.gov (United States)

    Lee, Chyi-Tyi

    2014-05-01

    Elevations in a mature mountain are generally normally distributed and slope gradients do. Shallow landslides occur on hill slopes and involve only regolith on the slopes. The slope gradient distribution of shallow landslides (including rock falls) is also a normal distribution; similar to that of natural slopes in shape, but shifting to a higher gradient. A probability of failure curve, which is defined as the ratio of landslide cells and total cells at each interval of a factor, then shows a shape close to a cumulative normal distribution and may be fitted with a Weibull curve. The probability of failure curve commonly shows an increase of failure from gradient about 0.5 to about 1.5, and then become saturated. There are few landslides located at slope less than about 26 degrees and lost its correlation with slope when slope greater than about 56 degrees, indicating landslide type change (rock falls). This is true for the storm-induced landslides. As to the earthquake-induced landslides, there are differences to the storm-induced landslides both in distribution curve and probability of failure curve. Earthquake-induced landslides most occurred at slope gradient from 20 degrees to 54 degrees and shows a mode about 42 degrees, whereas storm-induced landslides most occurred at slope gradient from 20 degrees to 44 degrees and shows a mode about 33 degrees. There are fewer occurrences of rock falls in a storm event than that in an earthquake event. Also, earthquake-induced landslides do not show saturation at higher slope gradients in the probability of failure curve. Normally distributed topographic pattern may skew in young mountains, like those in southern Taiwan or hilly terrain in western Taiwan, and the characteristic Weibull-shaped probability of failure curve may change also. It even becomes not applicable when a very extreme storm event is involved, like typhoon Morakot event in 2009 in southern Taiwan.

  7. In-Place Randomized Slope Selection

    DEFF Research Database (Denmark)

    Blunck, Henrik; Vahrenhold, Jan

    Slope selection is a well-known algorithmic tool used in the context of computing robust estimators for fitting a line to a collection P of n points in the plane. We demonstrate that it is possible to perform slope selection in expected O(nlogn) time using only constant extra space in addition to...

  8. Slope Stability. CEGS Programs Publication Number 15.

    Science.gov (United States)

    Pestrong, Raymond

    Slope Stability is one in a series of single-topic problem modules intended for use in undergraduate and earth science courses. The module, also appropriate for use in undergraduate civil engineering and engineering geology courses, is a self-standing introduction to studies of slope stability. It has been designed to supplement standard…

  9. Internal waves and temperature fronts on slopes

    Directory of Open Access Journals (Sweden)

    S. A. Thorpe

    Full Text Available Time series measurements from an array of temperature miniloggers in a line at constant depth along the sloping boundary of a lake are used to describe the `internal surf zone' where internal waves interact with the sloping boundary. More small positive temperature time derivatives are recorded than negative, but there are more large negative values than positive, giving the overall distribution of temperature time derivatives a small negative skewness. This is consistent with the internal wave dynamics; fronts form during the up-slope phase of the motion, bringing cold water up the slope, and the return flow may become unstable, leading to small advecting billows and weak warm fronts. The data are analysed to detect `events', periods in which the temperature derivatives exceed a set threshold. The speed and distance travelled by `events' are described. The motion along the slope may be a consequence of (a instabilities advected by the flow (b internal waves propagating along-slope or (c internal waves approaching the slope from oblique directions. The propagation of several of the observed 'events' can only be explained by (c, evidence that the internal surf zone has some, but possibly not all, the characteristics of the conventional 'surface wave' surf zone, with waves steepening as they approach the slope at oblique angles.

    Key words. Oceanography: general (benthic boundary layers; limnology, Oceanography: physical (internal and inertial waves

  10. Research on the stability evaluation of slope

    International Nuclear Information System (INIS)

    In order to create the guideline corresponding to a new regulatory standard, such as criteria in the ground-slope stability evaluation method, we have conducted an analysis and discussion of the shaking table test results using a large slope model. As a result, it was found that in that phase of the vertical motion and the horizontal motion affects the amplification characteristics of the ground motion, need to be considered in assessing the safety of the slope and the influence of the phase difference amplification or local. We also conduct a study on countermeasure construction slope by shaking table test, the effect of the countermeasure construction of pile and anchors deterrence could be confirmed. Focusing on the new method can reproduce the behavior of large deformation and discontinuity, with respect to the advancement of slope analysis, we identify issues on the maintenance and code applicability of each analysis method. (author)

  11. Automated sliding susceptibility mapping of rock slopes

    Directory of Open Access Journals (Sweden)

    A. Günther

    2004-01-01

    Full Text Available We present a suite of extensions for ARCVIEW GIS™ (ESRI that allows to map the spatial distribution of first-order mechanical slope-properties in hard rock terrain, e.g. for large slope areas like water reservoir slopes. Besides digital elevation data, this expert-system includes regional continuous grid-based data on geological structures that might act as potential sliding or cutoff planes for rockslides. The system allows rapid automated mapping of geometrical and kinematical slope properties in hard rock, providing the basis for spatially distributed deterministic sliding-susceptibility evaluations on a pixel base. Changing hydrostatic slope conditions and rock mechanical parameters can be implemented and used for simple predictive static stability calculations. Application is demonstrated for a study area in the Harz Mts., Germany.

  12. Rock slopes and reservoirs - lessons learned

    International Nuclear Information System (INIS)

    Lessons learned about slope stability in the course of four decades of monitoring, and in some cases stabilizing, slopes along British Columbia's hydroelectric reservoirs are discussed. The lessons are illustrated by short case histories of some of the more important slopes such as Little Chief Slide, Dutchman's Ridge, Downie Slide, Checkerboard Creek and Wahleach. Information derived from the monitoring and other investigations are compared with early interpretations of geology and slope performance. The comparison serves as an indicator of progress in slope stability determination and as a measure of the value of accumulated experience in terms of the potential consequences to safety and cost savings over the long life-span of hydroelectric projects.14 refs., 2 tabs., 15 figs

  13. Factors affecting seismic response of submarine slopes

    Directory of Open Access Journals (Sweden)

    G. Biscontin

    2006-01-01

    Full Text Available The response of submerged slopes on the continental shelf to seismic or storm loading has become an important element in the risk assessment for offshore structures and 'local' tsunami hazards worldwide. The geological profile of these slopes typically includes normally consolidated to lightly overconsolidated soft cohesive soils with layer thickness ranging from a few meters to hundreds of meters. The factor of safety obtained from pseudo-static analyses is not always a useful measure for evaluating the slope response, since values less than one do not necessarily imply slope failure with large movements of the soil mass. This paper addresses the relative importance of different factors affecting the response of submerged slopes during seismic loading. The analyses use a dynamic finite element code which includes a constitutive law describing the anisotropic stress-strain-strength behavior of normally consolidated to lightly overconsolidated clays. The model also incorporates anisotropic hardening to describe the effect of different shear strain and stress histories as well as bounding surface principles to provide realistic descriptions of the accumulation of the plastic strains and excess pore pressure during successive loading cycles. The paper presents results from parametric site response analyses on slope geometry and layering, soil material parameters, and input ground motion characteristics. The predicted maximum shear strains, permanent deformations, displacement time histories and maximum excess pore pressure development provide insight of slope performance during a seismic event.

  14. Effects of ongoing glacier retreat on steep valley-side drift slopes in the upper Bødalen valley, western Norway

    Science.gov (United States)

    Laute, Katja; Beylich, Achim A.; Oppikofer, Thierry

    2013-04-01

    The general pattern and dominant trend of today's mountain glaciers worldwide is a retreat of glacier fronts, indicating a significant volume decrease. Negative glacier net balances have been recorded for all Scandinavian glaciers after 1999. The ongoing glacier retreat enlarges freshly exposed proglacial areas which are characterized by e.g. comparably higher intensities of denudational slope processes and higher sediment availability. This study focuses on influences of rapid glacier regression on contemporary surface processes acting on steep valley-side drift slopes in a characteristic steep, parabolic-shaped and glacier-fed valley (Bødalen,) located on the western side of the Jostedalsbreen ice cap in western Norway. The Bødalsbreen is one of the glaciers with the highest retreat rate in entire Norway. Since the Little Ice Age (LIA) glacier maximum advance (1750) the glacier retreated ca. 1.500 m, including 65 m of retreat within the period of 2001 to 2010. Due to this retreat large areas of unstable hillslopes covered by glacial deposits from the LIA lateral moraines have been exposed. A combination of high resolution terrestrial laser scanning (TLS) and a designed monitoring program has been applied to a selected hillslope site on the eastern flank of the Bødalsbreen. Three sequential terrestrial laser scans have been acquired in the summers of 2010, 2011 and 2012. The analysis of the three series of the high resolution point clouds enables (i) the detection of unstable slope areas, (ii) areas characterized primarily by erosion or deposition processes and (iii) to quantify volumes of mass transfers at the scanned site. The results from the TLS measurements are combined with the results from the monitoring program (installations in operation since 2009) which includes remote cameras for monitoring rapid mass movement events (avalanches, slush- and debris flows), stone tracer lines for measuring surface movements as well as temperature loggers both in rock walls and talus slopes for analyzing rock temperatures and mechanical weathering at this slope test site. In addition, slope wash traps for analyzing slope wash denudation have been installed and measurements of solute concentrations at small hillslope drainage creeks for investigating the role of chemical denudation have been conducted. Results show that after the retreat of the LIA glacier the lateral moraines still act as significant sediment sources, being mainly eroded along the moraine crest and within incised gullies. Most of the eroded material is reworked through secondary processes like rock falls, snow avalanches and debris-flows and slope wash processes. Regarding geomorphic mass transfers especially the freshly exposed (since the last 12 years) slope areas are comparable important as sediment is delivered through slope-channel coupling into the fluvial system (whereas the level of slope-channel coupling within the entire drainage basins is altogether rather limited). Further extension of these freshly exposed areas will increase sediment delivery rates from upper valley systems which is also expected to affect the downstream parts of the drainage basin.

  15. On the Slope of Fibred Surfaces

    OpenAIRE

    Barja Yáñez, Miguel Ángel; Zucconi, Franco

    1999-01-01

    Given a relatively minimal non locally trivial fibred surface f: S->B, the slope of the fibration is a numerical invariant associated to the fibration. In this paper we explore how properties of the general fibre of $f$ and global properties of S influence on the lower bound of the slope. First of all we obtain lower bounds of the slope when the general fibre is a double cover. We also obtain a lower bound depending as an increasing function on the relative irregularity of t...

  16. On the Slope of Fibred Surfaces

    CERN Document Server

    Barja, M A; Barja, Miguel A.; Zucconi, Francesco

    1999-01-01

    Given a relatively minimal non locally trivial fibred surface f: S->B, the slope of the fibration is a numerical invariant associated to the fibration. In this paper we explore how properties of the general fibre of $f$ and global properties of S influence on the lower bound of the slope. First of all we obtain lower bounds of the slope when the general fibre is a double cover. We also obtain a lower bound depending as an increasing function on the relative irregularity of the fibration, extending previous results of Xiao. We construct several families of examples to check the assimptotical sharpness of our bounds.

  17. North Slope, Alaska ESI: FISH (Fish Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and freshwater fish species for the North Slope of Alaska. Vector...

  18. ElevationOther_SLOPE10M

    Data.gov (United States)

    Vermont Center for Geographic Information — Used ElevationDEM_DEM10M and the Arc/Info SLOPE command with the "PERCENT_RISE" and ".3048" Z_unit options to create this data layer. Input source dataset is...

  19. Slope activity in Gale crater, Mars

    Science.gov (United States)

    Dundas, Colin M.; McEwen, Alfred S.

    2015-07-01

    High-resolution repeat imaging of Aeolis Mons, the central mound in Gale crater, reveals active slope processes within tens of kilometers of the Curiosity rover. At one location near the base of northeastern Aeolis Mons, dozens of transient narrow lineae were observed, resembling features (Recurring Slope Lineae) that are potentially due to liquid water. However, the lineae faded and have not recurred in subsequent Mars years. Other small-scale slope activity is common, but has different spatial and temporal characteristics. We have not identified confirmed RSL, which Rummel et al. (Rummel, J.D. et al. [2014]. Astrobiology 14, 887-968) recommended be treated as potential special regions for planetary protection. Repeat images acquired as Curiosity approaches the base of Aeolis Mons could detect changes due to active slope processes, which could enable the rover to examine recently exposed material.

  20. Factorisation of Regge slopes for multiquark hadrons

    International Nuclear Information System (INIS)

    Using duality and the factorisation relationships between residues, general rules for expressing the Regge slopes of multi-quark hadrons without string loops in terms of those of the standard three quark baryons and two quark mesons are presented

  1. North Slope, Alaska ESI: BIRDS (Bird Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for diving birds, gulls and terns, seabirds, shorebirds, and waterfowl for the North Slope of Alaska....

  2. North Slope, Alaska ESI: FACILITY (Facility Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data for oil field facilities for the North Slope of Alaska. Vector points in this data set represent oil field facility locations. This data...

  3. North Slope, Alaska ESI: FISHL (Fish Lines)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for anadromous and freshwater fish species for the North Slope of Alaska. Vector lines in this data set...

  4. Percent Agricultural Land Cover on Steep Slopes

    Data.gov (United States)

    U.S. Environmental Protection Agency — Clearing land for agriculture tends to increase soil erosion. The amount of erosion is related to the steepness of the slope, farming methods used and soil type....

  5. 3D geodetic monitoring slope deformations

    Directory of Open Access Journals (Sweden)

    Weiss Gabriel

    1996-06-01

    Full Text Available For plenty of slope failures that can be found in Slovakia is necessary and very important their geodetic monitoring (because of their activity, reactivisations, checks. The paper gives new methodologies for these works, using 3D terrestrial survey technologies for measurements in convenient deformation networks. The design of an optimal type of deformation model for various kinds of landslides and their exact processing with an efficient testing procedure to determine the kinematics of the slope deformations are presented too.

  6. Numerical Computation of Homogeneous Slope Stability

    OpenAIRE

    Xiao, Shuangshuang; Li, Kemin; Ding, Xiaohua; Liu, Tong

    2015-01-01

    To simplify the computational process of homogeneous slope stability, improve computational accuracy, and find multiple potential slip surfaces of a complex geometric slope, this study utilized the limit equilibrium method to derive expression equations of overall and partial factors of safety. This study transformed the solution of the minimum factor of safety (FOS) to solving of a constrained nonlinear programming problem and applied an exhaustive method (EM) and particle swarm optimization...

  7. Rock Slopes from Mechanics to Decision Making

    OpenAIRE

    Einstein, H.H.; de Sousa, R. L.; Karam, K.; Manzella, Irène; Kveldsvik, V.

    2010-01-01

    Rock slope instabilities are discussed in the context of decision making for risk assessment and management. Hence, the state of the slope and possible failure mechanism need to be defined first. This is done with geometrical and mechanical models for which recent developments are presented. This leads with appropriate consideration of uncertainties to risk determination and to the description of tools for risk management through active and passive countermeasures, including warning systems. ...

  8. Seasonal slope surface deformation measured with TLS

    Science.gov (United States)

    Fan, L.; Smethurst, J.; Powrie, W.; Sellaiya, A.

    2014-03-01

    In temperate European climates, soil water removal due to vegetation transpiration peaks in summer and soil rewetting from higher levels of precipitation occurs in winter. In clays of high plasticity, the seasonal cycles of drying and wetting cause the soil to experience a volumetric change, resulting in seasonal shrinking and swelling. For a clay slope exhibiting volume change, such behaviour can lead to excessive deformation and could contribute to strain-softening and progressive slope failure. This can in turn cause traffic disruption and loss of life if roads and railways are founded on or surrounded by such slopes. This paper discusses the driving forces of seasonal surface movement, in particular the role of vegetation, and presents the use of Terrestrial Laser Scanning (TLS) to measure the surface movement of a lightly vegetated London Clay slope near Newbury, UK. Two TLS scans were carried out in early and late summer respectively, representing relative wet and dry conditions of the slope. Continuous field measurements of soil water content in upper layers of the slope were obtained from TDR ThetaProbes already installed at the site. The water content data are used to support the results obtained from TLS by indicating the likely volumetric change in the soil due to loss of water.

  9. Electrokinetic Geotextile Stabilization Of Embankment Slopes

    Directory of Open Access Journals (Sweden)

    Mumtaz M

    2014-12-01

    Full Text Available The choice of repair of slope depends on site conditions and cost. This includes reducing the slope, installing horizontal drains, soil nailing and providing stability by structural methods. All these methods have their limitations and some are very costly. Another alternative is the electrokinetic stabilization of slopes. EKG reinforcement or soil nails not only provide reinforcement, but also increase the shear strength of the soil in which they are placed as well as improving soil-reinforcement bond. The development of EKG materials offers slope stabilisation of embankments and cuttings in fine grained soils, which will significantly increase the factor of safety , address pore pressure changes and also avoids importing earthwork materials or aggregates. By inserting a grid of anodes and a cathode into the ground and applying an electrical potential difference across the slope drives water away, via the cathodes and creates physical changes in the embankment, promoting consolidation of the slope materials. Anodes and cathodes were connected to a DC power circuit and electrified for a calculated period based on water content, strength and electrode spacing. The conductive geotextile used was coir geotextile and it was woven with steel filament in weft direction only. The steel filament made the geotextile conductive. The geotextile used was natural geotextile and it is required after the end of construction of embankment only, till the completion of dissipation of pore pressure.

  10. Contribution of terrestrial and helicopter based laser scanning for studying the Sechilienne rock slope instability (Isère, France)

    Science.gov (United States)

    Vulliez, Cindy; Abellan Fernandez, Antonio; Guerin, Antoine; Jaboyedoff, Michel; Derron, Marc-Henri; Chanut, Marie-Aurélie; Dubois, Laurent; Duranthon, Jean-Paul

    2015-04-01

    The Sechilienne landslide, which is located in the Romanche valley (France) is a well instrumented mass movements of about 650 m high and 250 m wide, with a potential volume of 3 million cubic meters of material in the active part (Duranthon, 2004; Kasperski, 2010). The slope, which is mainly composed of micaschist, is characterized by the presence of a NE-SW sub-vertical fracturing system involved in the destabilization of the area. Several investigations are being performed by different research groups on this landslide, including fieldwork investigations, remote sensing, seismic acquisitions, geochemistry, deformation analysis by extensometers, etc. There exists a current concern related with the development of a failure that could dam the Romanche River, which could cause flooding with significant consequences for the valley downstream. The rock slope has continuously moving since the eighties decade, with a progressive acceleration during the last years. Furthermore, a higher rockfall activity has been observed in 2013, with two main events within the upper most active part of the landslide, with volumes of 1500 and 2500 m3. In this work, we used Terrestrial Laser Scanning to obtain high resolution point clouds of the rock slope geometry in order to monitor the rock slide displacements in three dimensions. Eight different fieldwork campaigns were performed during the last five years, as follows: Aug. 2009, Jul. 2010, Nov. 2011, Nov. 2012, Jun. and Nov. 2013, Jul. and Oct. 2014, which provides a set of 3D representations of the rock slope topography over time. Furthermore, three helicopter-based laser scanning campaigns were performed in Jan. 2011, Feb. 2012 and Feb. 2014 (Chanut, 2014). Both the type of data are complementary for the study of the movement and allow to have a good spatial vision of the evolution of the most active part. Data processing was carried out through several steps using Polyworks software, as follows: (a) cleaning of scans, (b) alignment of the scans using only the stable areas of the slope, (c) georeferencing, and (d) comparisons among all the scans. As for the results, we obtained positive and negative values of surface changes between the period of study, which enabled us to characterize rockfalls and displacements on the rock slope. In the upper part, we observed that several areas (from 1 to 1000 m3) suffered higher values of displacements (from several decimeters to a maximum value of 4 meters), indicating the presence of a progressive failure in these parts of the slope. The failure mechanism observed on this areas correspond to a toppling. On the lower part of the rock slope we observed the accumulation of the fallen material and a series of surface processes on the talus. Furthermore, we carried out the tracking of hundred blocks in the upper part of the slope in order to identify potential events. Once the individual blocks fell, we used 3DReshaper for calculating their volumes and for determining a power law distribution of rock falls in the slope. The acquisition of dense and accurate terrain information using LiDAR for study the Sechilienne landslide has been useful for investigating the unstable area as regards the failure mechanism, the magnitude of displacements, the rockfall frequency of the most unstable areas, etc.

  11. Slope Failures Triggered by the 1923 Kanto Earthquake and Comparison With Rainfall- induced Slope Failures

    Science.gov (United States)

    Ishikawa, M.; Hayashi, S.; Komito, Y.; Honda, Y.

    2006-12-01

    Slope failures are major natural hazards in the Tanzawa Mountain adjacent to Tokyo-Yokohama metropolitan region, and rainfall is a main mechanism that triggers slope failures. However, the mountainous area is located on the plate boundary of arc-arc collision type, and the active mountain-building region has experienced the Kanto earthquake (M7.9) in 1923. In a previous paper, Ishikawa et al (2005) pointed out that the Kanto earthquake triggered serious slope failures (about 20,000 places and 58.5 km2 area) in the Tanzawa Mountain and the neighboring mountainous area. Therefore, to assess hazard and risk of slope failures in the mountainous region that will suffer the next catastrophic earthquake it is necessary to understand characteristics of rainfall-induced and earthquake-induced slope failures. In order to compare the impact of the Kanto earthquake on slope failures with that of rainfall, the 182 km2 area in the Tanzawa Mountain was selected as the study area, and a GIS was used to conduct a spatial characterization of the slope failures. Slope failures induced by the Kanto Earthquake were digitized from maps, and rainfall-induced slope failures were identified from 210 aerial photographs taken in 1985 and 1996. Compared with these data, we find that only 0.50 km2 slope failures were induced by rainfalls during 1985-1996, while 20.2 km2 slope failures almost forty times larger than those caused by the rainfalls during 1985-1996 were triggered by the Kanto Earthquake. Assuming that occurrence rate of rainfall-induced slope failures is constant over a long period of time, the total area of the earthquake-induced slope failures is equivalent to that of the rainfall-induced slope failures for 220 years. The major difference in distribution of slope failures between the Kanto earthquake and rainfall was the distribution of elevation. Overall, concentration values of slope failures increase with higher elevation reaching a maximum at highest elevation (1500 m - 1600 m), while those of slope failures caused by the Kanto earthquake show no significant change with elevation from 300 m to 1400 m and diminish beyond elevation of 1400 m where Beech forest occupies. We note that the impact of the Kanto Earthquake on the surface environment of the Tanzawa Mountain is devastating compared to that of rainfall. The seismic hazard and subsequent risk e.g. fresh water depletion and drinking water crisis should be assessed by considering the fact that the Tanzawa Mountain is an important water source for mega-city Yokohama.

  12. 3-D slope stability analysis: A probability approach applied to the nice slope (SE France)

    OpenAIRE

    Leynaud, Didier; Sultan, Nabil

    2010-01-01

    Recent geophysical and geotechnical data acquired on the Nice shelf to the east of the 1979 landslide source area, Suggest slow deformations processes which could lead to future catastrophic slope failure. According to these preliminary interpretations, it is of major interest to perform a slope stability evaluation to define the hazard and quantify the danger related to a probable instability on this slope. A probabilistic approach is proposed here using a modified version of the SAMU_3D mod...

  13. Value of magnetic resonance imaging in the mid-term follow-up of osteochondritis dissecans of the femoral condyle and talus

    International Nuclear Information System (INIS)

    Purpose: Definition of the prognostic value of clinical and morphological findings in the mid-term follow-up of OCD of the femoral condyle and talus. Demonstration of the consolidation of OCD on MRI depending on different therapies. Materials and Methods: 76 patients were examined before and at an average of 30 months after conservative or surgical therapy using T1 and T2 weighted SE and 3D-FISP sequences and contrast enhanced studies. Six clinical (age, gender, site, duration and severity of symptoms, therapy) and six morphological (size, signal intensity, fragmentation, contrast enhancement, condition of cartilage, staging) data were registered on first MRI and correlated with the degree of consolidation of OCD (partial and complete remission, no change and progression) on control MRI. Results: Patients under 17 years showed partial or complete remissions in 73%, those of 17 years or older in 33%. Conservatively treated patients had a higher remission rate (54%) than those treated with different surgical techniques (drilling 50%, refixation 43%, abrasio 38%). Small OCDs had a higher remission rate than large lesions (63% vs. 33%). OCDs covered with intact cartilage healed better than lesions with chondral defects (61% vs. 26%). Contrast enhancing fragments had a better prognosis than non-enhancing lesions (100% vs. 40%). Conclusions: Prognosis of OCD can be better estimated when size of OCD, condition of cartilage and enhancement of contrast agent is graduated with MRI and patient age is registered. The consequences for therapy planning are great. (orig.)

  14. Decision Guide for Roof Slope Selection

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, T.R.

    1988-01-01

    This decision guide has been written for personnel who are responsible for the design, construction, and replacement of Air Force roofs. It provides the necessary information and analytical tools for making prudent and cost-effective decisions regarding the amount of slope to provide in various roofing situations. Because the expertise and experience of the decision makers will vary, the guide contains both basic slope-related concepts as well as more sophisticated technical data. This breadth of information enables the less experienced user to develop an understanding of roof slope issues before applying the more sophisticated analytical tools, while the experienced user can proceed directly to the technical sections. Although much of this guide is devoted to the analysis of costs, it is not a cost-estimating document. It does, however, provide the reader with the relative costs of a variety of roof slope options; and it shows how to determine the relative cost-effectiveness of different options. The selection of the proper roof slope coupled with good roof design, a quality installation, periodic inspection, and appropriate maintenance and repair will achieve the Air Force's objective of obtaining the best possible roofing value for its buildings.

  15. Geomorphologic mapping in the Ny Ålesund area (Svalbard Island, Norway) for the analysis of geomorphologic effects on rock slopes induced by glacier retreat in climate sensitive High Arctic regions

    Science.gov (United States)

    Miccadei, Enrico; Piacentini, Tommaso; Casacchia, Ruggero; Sparapani, Roberto

    2014-05-01

    The geomorphological effects of glacial retreat, rapidly changing Arctic environments and consequent local temporary permafrost melting are several types of glacial and periglacial landforms (pingos, solifluction, drumlins, etc.) but also debris and rock falls, alluvial fan and glacial outwash development and scarp/slopes retreat and evolution. In this work we have realized a geomorphologic map of rockfalls, landslides, alluvial fans and the slopes and scarps of steep mountainsides in the Ny Ålesund area (Svalbard Island, Norway) focused on the analysis of rock falls as geomorphological effects of glacier retreat, permafrost degradation and higher temperatures on slope processes. The investigation is based on geological and geomorphological field survey, and remote sensing and aerial photo interpretation, The Ny Ålesund area landscape is characterized by rugged non-vegetated mountains only partially covered by glaciers, with steep flanks and rock scarps; the scarps are formed by different types of rocks (intrusive and effusive igneous rocks, marine sedimentary rocks); this landscape is highly affected by debris and rock falls (from scarps and slopes) forming wide talus slopes and by alluvial fan and fluvial outwash (from glaciers), which make the surface sedimentary cover of the island together with rock glaciers and moraine deposits and locally fluvial deposits. The work is focused on the comprehension of the role of different factors in inducing rock falls, alluvial fans, slope/scarps evolution in high geomorphological sensitivity environments (i.e. glacial, periglacial or mountain) including: orography, lithology, rock fracturation, morphostructural setting, meteorological context. The conclusions focus on the possible geomorphological hazards affecting the Ny Ålesund area.

  16. The great slippery-slope argument.

    Science.gov (United States)

    Burgess, J A

    1993-09-01

    Whenever some form of beneficent killing--for example, voluntary euthanasia--is advocated, the proposal is greeted with a flood of slippery-slope arguments warning of the dangers of a Nazi-style slide into genocide. This paper is an attempt systematically to evaluate arguments of this kind. Although there are slippery-slope arguments that are sound and convincing, typical formulations of the Nazi-invoking argument are found to be seriously deficient both in logical rigour and in the social history and psychology required as a scholarly underpinning. As an antidote, an attempt is made both to identify some of the likely causes of genocide and to isolate some of the more modest but legitimate fears that lie behind slippery-slope arguments of this kind. PMID:8230150

  17. Centrifuge model test of rock slope failure caused by seismic excitation. Plane failure of dip slope

    International Nuclear Information System (INIS)

    Recently, it is necessary to assess quantitatively seismic safety of critical facilities against the earthquake induced rock slope failure from the viewpoint of seismic PSA. Under these circumstances, it is essential to evaluate more accurately the possibilities of rock slope failure and the potential failure boundary, which are triggered by earthquake ground motions. The purpose of this study is to analyze dynamic failure characteristics of rock slopes by centrifuge model tests for verification and improvement of the analytical methods. We conducted a centrifuge model test using a dip slope model with discontinuities limitated by Teflon sheets. The centrifugal acceleration was 50G, and the acceleration amplitude of input sin waves increased gradually at every step. The test results were compared with safety factors of the stability analysis based on the limit equilibrium concept. Resultant conclusions are mainly as follows: (1) The slope model collapsed when it was excited by the sine wave of 400gal, which was converted to real field scale, (2) Artificial discontinuities were considerably concerned in the collapse, and the type of collapse was plane failure, (3) From response acceleration records observed at the slope model, we can say that tension cracks were generated near the top of the slope model during excitation, and that might be cause of the collapse, (4) By considering generation of the tension cracks in the stability analysis, correspondence of the analytical results and the experimental results improved. From the obtained results, we need to consider progressive failure in evaluating earthquake induced rock slope failure. (author)

  18. Slopes of smooth curves on Fano manifolds

    OpenAIRE

    Hwang, Jun-Muk; Kim, Hosung; Lee, Yongnam; Park, Jihun

    2010-01-01

    Ross and Thomas introduced the concept of slope stability to study K-stability, which has conjectural relation with the existence of constant scalar curvature K\\"ahler metric. This paper presents a study of slope stability of Fano manifolds of dimension $n\\geq 3$ with respect to smooth curves. The question turns out to be easy for curves of genus $\\geq 1$ and the interest lies in the case of smooth rational curves. Our main result classifies completely the cases when a polar...

  19. The great slippery-slope argument.

    OpenAIRE

    Burgess, J A

    1993-01-01

    Whenever some form of beneficent killing--for example, voluntary euthanasia--is advocated, the proposal is greeted with a flood of slippery-slope arguments warning of the dangers of a Nazi-style slide into genocide. This paper is an attempt systematically to evaluate arguments of this kind. Although there are slippery-slope arguments that are sound and convincing, typical formulations of the Nazi-invoking argument are found to be seriously deficient both in logical rigour and in the social hi...

  20. The Sloping Land Conversion Program in China

    DEFF Research Database (Denmark)

    Liu, Zhen

    By overcoming the barriers that limit access to financial liquidity and human resource, the Sloping Land Conversion Program (SLCP) can promote rural livelihood diversification. This paper examines this effect using a household survey data set spanning the 1999 implementation of the Sloping land...... conversion program. Our results show that SLCP works as a valid external policy intervention on rural livelihood diversification. In addition, the findings demonstrate that there exist heterogeneous effects of SLCP implementation on livelihood diversification across different rural income groups. The lower...... income group was more affected by the program in terms of income diversification....

  1. Radial slope measurement of dynamic transparent samples

    International Nuclear Information System (INIS)

    An interferometric method to measure the radial slope of dynamic transparent samples is presented. We have implemented a simultaneous phase shifting Mach–Zehnder radial-shear interferometer (SPS-MZRI) using a phase grating to replicate the interference patterns and phase shifts modulated by polarization; the interferometer is capable of processing the optical phase data through the acquisition of n-interferograms captured simultaneously. The SPS-MZRI is capable of obtaining the radial phase derivative and associating it with its corresponding radial slope. The experimental results for static and dynamic samples are presented in this work, as well as the experimental evidence for the generation of spiral patterns. (paper)

  2. Monitoring hazardous open pit mine slope.

    Czech Academy of Sciences Publication Activity Database

    Mrlina, Jan

    Houten : EAGE, 2012, C038/1-C038/5. ISBN 978-90-73834-27-9. [EAGE Conference & exhibition incorporationg SPE EUROPEC 2010 /74./. Copenhagen (DK), 04.06.2012-07.06.2012] R&D Projects: GA MŠk LM2010008 Institutional support: RVO:67985530 Keywords : tiltmeter * slope monitoring * open-pit mine Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  3. On the slope of bielliptic fibrations

    OpenAIRE

    Barja Yáñez, Miguel Ángel

    1997-01-01

    Let $\\pi :S\\longrightarrow B$ be a bielliptic fibration. We prove $S$ is, up to base change, a rational double cover of an elliptic fibration and that $\\pi $ is isotrivial provided it is smooth. Finally, we prove that the slope of $\\pi $ is at least four provided the genus of the fibre is at least six.

  4. Bright and Dark Slopes on Ganymede

    Science.gov (United States)

    1997-01-01

    Ridges on the edge of Ganymede's north polar cap show bright east-facing slopes and dark west-facing slopes with troughs of darker material below the larger ridges. North is to the top. The bright slopes may be due to grain size differences, differences in composition between the original surface and the underlying material, frost deposition, or illumination effects. The large 2.4 kilometer (1.5 mile) diameter crater in this image shows frost deposits located on the north-facing rim slope, away from the sun. A smaller 675 meter (2200 foot) diameter crater in the center of the image is surrounded by a bright deposit which may be ejecta from the impact. Ejecta deposits such as this are uncommon for small craters on Ganymede. This image measures 18 by 19 kilometers (11 by 12 miles) and has a resolution of 45 meters (148 feet) per pixel. NASA's Galileo spacecraft obtained this image on September 6, 1996 during its second orbit around Jupiter.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  5. Assessment of slope stability endangered by groundwater.

    Czech Academy of Sciences Publication Activity Database

    Procházka, P.; Tr?ková, Ji?ina

    Southampton : WIT Press, 2006 - (Brebbia, C.; Conti, M.; Tiezzi, E.), s. 709-718 ISBN 978-1-84564-048-4. [Ravage of Planet. Baryloche (AR), 12.12.2006-14.12.2006] R&D Projects: GA AV ?R IAA2119402 Institutional research plan: CEZ:AV0Z30460519 Keywords : physical and numerical modelling * slope stability * groundwater Subject RIV: JN - Civil Engineering

  6. Fractal Rock Slope Dynamics Anticipating a Collapse.

    Czech Academy of Sciences Publication Activity Database

    Paluš, Milan; Novotná, Dagmar; Zvelebil, J.

    2005-01-01

    Ro?. 7, - (2005), s. A-09729. ISSN 1029-7006. [General Asembly of the European Geophysical Society. 24.04.2005-29.04.2005, Vienna] R&D Projects: GA AV ?R 1ET110190504 Institutional research plan: CEZ:AV0Z10300504 Keywords : slope movement * landslide * collapse * prediction * fractal Subject RIV: BA - General Mathematics

  7. Fractal Rock Slope Dynamics Anticipating a Collapse.

    Czech Academy of Sciences Publication Activity Database

    Paluš, Milan; Novotná, Dagmar; Zvelebil, Ji?í

    2004-01-01

    Ro?. 70 (2004), 036212. ISSN 1063-651X R&D Projects: GA ?R GA205/00/1055 Institutional research plan: CEZ:AV0Z1030915 Keywords : fractal * scaling * unstable rock slope * collapse prediction * engineering geology Subject RIV: BA - General Mathematics Impact factor: 2.352, year: 2004

  8. Evaluation of Slope Stability Performance in Different Methods

    Directory of Open Access Journals (Sweden)

    Abdoullah Namdar,

    2010-07-01

    Full Text Available The magnitude of liquefaction is changing respect to level of underground water, soil mechanical properties, time, direction and magnitude of forces. In this research work to understanding slope failure mechanism the limit equilibrium code employed to evaluating slope stability and assessing failure. The result revealed that thefailure of slope could be predicted if accurate slope behavior investigated. For increasing soil structure stability and loads mitigation this is essential of appropriate selection of slope geometry based on evaluating of slope at different slope geometry.

  9. Development of Probabilistic Safety Assessment Considering Slope Collapse by Earthquake

    International Nuclear Information System (INIS)

    In Japan, a part of nuclear power plants is surrounded by the land slope. In such a nuclear power plant, it is necessary to evaluate the stability of the slope under the deterministic seismic condition, and to ascertain that the plant is kept in a safe condition even if collapse of the slope might occur due to earthquakes. A probabilistic safety assessment methodology considering the slope collapse (Slope PSA) has been developed as a part of seismic PSA at Japan Nuclear Energy Safety Organization (JNES). This method consists of slope collapse hazard evaluation, fragility evaluation (evaluation of secondary influences on nuclear facilities) and system reliability analysis. In the slope collapse hazard evaluation, probabilities of slope stability, failure modes, collapse behavior, rock reach area and shock force to nuclear facility are analyzed and calculated. This report describes the slope collapse hazard evaluation procedure and sample calculations for a model slope, and also results of parametric studies for the rock block behavior analysis. (authors)

  10. Analysis of Rainfall Infiltration Law in Unsaturated Soil Slope

    OpenAIRE

    Gui-rong Zhang; Ya-jun Qian; Zhang-chun Wang; Bo Zhao

    2014-01-01

    In the study of unsaturated soil slope stability under rainfall infiltration, it is worth continuing to explore how much rainfall infiltrates into the slope in a rain process, and the amount of rainfall infiltrating into slope is the important factor influencing the stability. Therefore, rainfall infiltration capacity is an important issue of unsaturated seepage analysis for slope. On the basis of previous studies, rainfall infiltration law of unsaturated soil slope is analyzed. Considering t...

  11. Evaluation of Slope Assessment Systems for Predicting Landslides of Cut Slopes in Granitic and Meta-sediment Formations

    OpenAIRE

    Suhaimi Jamaludin; Bujang B.K.  Haut; Husaini Umar

    2006-01-01

    In Malaysia, slope assessment systems (SAS) are widely used in assessing the instability of slope or the probability of occurrence and the likely severity of landslides. These SAS can be derived based on either one particular approach or combination of several approaches of landslide assessments and prediction. This study overviews four slope assessment systems (SAS) developed in Malaysia for predicting landslide at a large-scale assessments. They are the Slope Maintenance System (SMS), Slope...

  12. Wildlife response on the Alaska North Slope

    International Nuclear Information System (INIS)

    Recognizing the need for a comprehensive plan to deal with potentially oiled wildlife on the Alaskan North Slope, a multifaceted wildlife protection strategy was developed and implemented during 1991. The strategy incorporated all aspects of wildlife response including protection of critical habitat, hazing, capture and stabilization, long term rehabilitation, and release. The primary wildlife response strategy emphasizes controlling of the release and spreading of spilled oil at the source to prevent or reduce contamination of potentially affected species and/or their habitat. A secondary response strategy concentrates on keeping potentially affected wildlife away from an oiled area through the use of deterrent techniques. Tertiary response involves the capture and treatment of oiled wildlife. Implementation of the strategy included the development of specialized training, the procurement of equipment, and the construction of a bird stabilization center. The result of this initiative is a comprehensive wildlife response capability on the Alaskan North Slope. 1 ref., 5 figs., 3 tabs

  13. CCN-supersaturation spectra slopes (k)

    Science.gov (United States)

    Jiusto, J. E.; Lala, G. G.

    1981-11-01

    Theoretically the slope k of a CCN-supesaturation spectrum should equal two thirds of the slope of the total (soluble) aerosol size distribution. Workshop results tended to verify this relation. The k values are markedly different depending on whether one is measuring ambient CCN concentrations at supersaturations S above or below approximately 0.1-0.2%. The larger k values for S approximately 0.1% is consistent with the greater decrease in large particle concentration with increasing size. It is concluded that over the S range of 0.02% to 2%, two power fits (and k values) may sometimes suffice for a reasonable approximation of the CCN distribution. At other times, and with laboratory generated aeosols, such an approach is inadequate and requires refinement.

  14. In-Place Randomized Slope Selection

    DEFF Research Database (Denmark)

    Blunck, Henrik; Vahrenhold, Jan

    2006-01-01

    Slope selection is a well-known algorithmic tool used in the context of computing robust estimators for fitting a line to a collection P of n points in the plane. We demonstrate that it is possible to perform slope selection in expected O(nlogn) time using only constant extra space in addition to the space needed for representing the input. Our solution is based upon a space-efficient variant of Matoušek’s randomized interpolation search, and we believe that the techniques developed in this paper will prove helpful in the design of space-efficient randomized algorithms using samples. To underline this, we also sketch how to compute the repeated median line estimator in an in-place setting.

  15. The Alaska North Slope spill analysis

    International Nuclear Information System (INIS)

    This paper reports Alaska North Slope crude oil spills, provides information to help operators identify risks and presents recommendations for future risk reduction and mitigation measures that may reduce the frequency and severity of future spills from piping infrastructure integrity loss. The North Slope spills analysis project was conducted during 2010 by compiling available spill data, and analyzing the cause of past spills in wells and associated piping, flowlines, process centers with their associated piping and above ground storage tanks, and crude oil transmission pipelines. An expert panel, established to provide independent review of this analysis and the presented data, identified seven recommendations on measures, programs, and practices to monitor and address common causes of failures while considering information provided from regulators and operators. These recommendations must be evaluated by the State of Alaska which will consider implementation options to move forward. Based on the study observations, future analyses may show changes to some of the observed trends.

  16. Affine permutations and rational slope parking functions

    OpenAIRE

    Gorsky, Eugene; Mazin, Mikhail; Vazirani, Monica

    2014-01-01

    We introduce a new approach to the enumeration of rational slope parking functions with respect to the area and a generalized dinv statistics, and relate the combinatorics of parking functions to that of affine permutations. We relate our construction to two previously known combinatorial constructions: Haglund's bijection exchanging the pairs of statistics (area,dinv) and (bounce,area) on Dyck paths, and Pak-Stanley labeling of the regions of k-Shi hyperplane arrangements b...

  17. On Front Slope Stability of Berm Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    2013-01-01

    The short communication presents application of the conventional Van der Meer stability formula for low-crested breakwaters for the prediction of front slope erosion of statically stable berm breakwaters with relatively high berms. The method is verified (Burcharth, 2008) by comparison with the reshaping of a large Norwegian breakwater exposed to the North Sea waves. As a motivation for applying the Van der Meer formula a discussion of design parameters related to berm breakwater stability formu...

  18. Ocean processes at the Antarctic continental slope

    OpenAIRE

    Heywood, Karen J.; Schmidtko, Sunke; Heuzé, Céline; Kaiser, Jan; Jickells, Timothy D.; Queste, Bastien; Stevens, David P.; Wadley, Martin; Thompson, Andrew F.; Fielding, Sophie; Guihen, Damien; Creed, Elizabeth; Ridley, Jeff K.; Smith, Walker

    2014-01-01

    The Antarctic continental shelves and slopes occupy relatively small areas, but, nevertheless, are important for global climate, biogeochemical cycling and ecosystem functioning. Processes of water mass transformation through sea ice formation/melting and ocean–atmosphere interaction are key to the formation of deep and bottom waters as well as determining the heat flux beneath ice shelves. Climate models, however, struggle to capture these physical processes and are unable to reproduce water...

  19. Back analysis of reinforced soil slopes.

    Czech Academy of Sciences Publication Activity Database

    Procházka, P.; Tr?ková, Ji?ina

    Southampton : WIT Press, 2012 - (Mammoli, A.; Brebbia, C.), s. 423-432 ISBN 978-1-84564-602-8. ISSN 1743-3533. [Computational methods and experiments in material characterisation /3./. Material Characterisation 2007. Bologna (IT), 13.06.2007-15.06.2007] R&D Projects: GA AV ?R IAA2119402 Institutional research plan: CEZ:AV0Z30460519 Keywords : back analysis * numerical and experimental modelling * slopes Subject RIV: JM - Building Engineering

  20. Slope stability under rapid drawdown conditions

    OpenAIRE

    Alonso Pérez de Agreda, Eduardo; Pinyol Puigmartí, Núria Mercè

    2009-01-01

    The rapid drawdown condition arises when submerged slopes experience rapid reduction of the external water level. Classical analysis procedures are grouped in two classes: the “stress-based” undrained approach, recommended for impervious materials and the flow approach, which is specified for rigid pervious materials (typically a granular soil). Field conditions often depart significantly from these simplified cases and involve materials of different permeability and compressibility arrang...

  1. Viscous liquid flow on Martian dune slopes

    CERN Document Server

    Dobrovolskis, Anthony R

    2014-01-01

    The observed temporary dark streaks on some dune slopes on Mars may be due to thin sheets of water (or some other liquid) trickling downhill. This note corrects conceptual errors in a previous paper (M\\"{o}hlmann and Kereszturi 2010, Icarus 207, 654-658) which affect the velocity profile of such flows, and produce over-estimates of their depths and mass fluxes by factors of almost two.

  2. Transhumanism, medical technology and slippery slopes

    OpenAIRE

    McNamee, M J; Edwards, S D

    2006-01-01

    In this article, transhumanism is considered to be a quasi?medical ideology that seeks to promote a variety of therapeutic and human?enhancing aims. Moderate conceptions are distinguished from strong conceptions of transhumanism and the strong conceptions were found to be more problematic than the moderate ones. A particular critique of Boström's defence of transhumanism is presented. Various forms of slippery slope arguments that may be used for and against transhumanism are discussed and on...

  3. Geosynthetic clay liners - slope stability field study

    International Nuclear Information System (INIS)

    A field research project was developed to examine the internal shear performance of geosynthetic clay liners (GCLs). Several combinations of cross sections were assembled using GCL materials that were available at the time of project initiation. The cross sections utilized were intended to simulate landfill cover applications. Thirteen (13) resulting test plots were constructed on two different slope angles, and each plot is instrumented for physical displacement and soil moisture characteristics. Test plots were constructed in a manner that dictated the shear plane in the clay portion of the GCL product. The project purpose is to assess field performance and to verify design parameters associated with the application of GCLs in waste containment applications. Interim research data shows that test slopes on 2H:1V show global deformation, but little internal shear evidence, and the 3H:1V slopes show little deformation at approximately 650 days. The research is ongoing, and this paper presents the most recent information available from the project

  4. Geosynthetic clay liners - slope stability field study

    Energy Technology Data Exchange (ETDEWEB)

    Carson, D.A. [Environmental Protection Agency, Cincinnati, OH (United States); Daniel, D.E. [Univ. of Illinois, Urbana, IL (United States); Koerner, R.M. [Geosynthetic Research Institute, Philadelphia, PA (United States); Bonaparte, R. [GeoSyntec Consultants, Atlanta, GA (United States)

    1997-12-31

    A field research project was developed to examine the internal shear performance of geosynthetic clay liners (GCLs). Several combinations of cross sections were assembled using GCL materials that were available at the time of project initiation. The cross sections utilized were intended to simulate landfill cover applications. Thirteen (13) resulting test plots were constructed on two different slope angles, and each plot is instrumented for physical displacement and soil moisture characteristics. Test plots were constructed in a manner that dictated the shear plane in the clay portion of the GCL product. The project purpose is to assess field performance and to verify design parameters associated with the application of GCLs in waste containment applications. Interim research data shows that test slopes on 2H:1V show global deformation, but little internal shear evidence, and the 3H:1V slopes show little deformation at approximately 650 days. The research is ongoing, and this paper presents the most recent information available from the project.

  5. Stability of sulfur slopes on Io

    Science.gov (United States)

    Clow, G. D.; Carr, M. H.

    1980-01-01

    The mechanical properties of elemental sulfur are such that the upper crust of Io cannot be primarily sulfur. For heat flows in the range 100-1000 ergs/sq cm sec sulfur becomes ductile within several hundred meters of the surface and would prevent the formation of calderas with depths greater than this. However, the one caldera for which precise depth data are available is 2 km deep, and this value may be typical. A study of the mechanical equilibrium of simple slopes shows that the depth to the zone of rapid ductile flow strongly controls the maximum heights for sulfur slopes. Sulfur scarps with heights greater than 1 km will fail for all heat flows greater than 180 ergs/sq cm sec and slope angles greater than 22.5 deg. The observed relief on Io is inconsistent with that anticipated for a predominantly sulfur crust. However, a silicate crust with several percent sulfur included satisfies both the mechanical constraints and the observed presence of sulfur on Io.

  6. Toric Slope Stability and Partial Bergman Kernels

    CERN Document Server

    Pokorny, Florian T

    2011-01-01

    Let $(L, h)\\to (X, \\omega)$ denote a polarized toric K\\"ahler manifold. Fix a toric submanifold $Y$ and denote by $\\hat{\\rho}_{lk}:X\\to \\mathbb{R}$ the partial density function corresponding to the partial Bergman kernel projecting smooth sections of $L^k$ onto holomorphic sections of $L^k$ that vanish to order at least $lk$ along $Y$, for fixed $l>0$ such that $lk\\in \\mathbb{N}$. We prove the existence of a distributional expansion of $\\hat{\\rho}_{lk}$ up to order $k^{n-2}$ as $k\\to \\infty$, including the identification of the coefficient of $k^{n-1}$ as a distribution on $X$. This expansion is used to give a direct proof that if $\\omega$ has constant scalar curvature, then $(X, L)$ must be slope semi-stable with respect to $Y$. More generally, it is shown that under the same hypotheses, $(X,L)$ must be slope semi-stable with respect to any closed toric subscheme $Z$ of $X$. In many cases, moreover, $(X,L)$ will be slope stable with respect to $Z$.

  7. Biostabilization of Mandaman dump slope, India

    Energy Technology Data Exchange (ETDEWEB)

    Chaulya, S.K.; Singh, R.S.; Chakraborty, M.K.; Tewary, B.K.; Srivastava, B.K. [Central Mining Research Institute, Dhanbad (India)

    2001-08-01

    An integrated study of the biological stabilization of a coal-mine overburden dump slope has been carried out at Mandaman, 35 km from Dhanbad in eastern India. Native grasses bamboo (Dendrocalmus strictus) and kashi (Saccharum spontaneum) are important species that can stabilize the dump slopes. The grasses have good soil binding capacity and help to control soil erosion and improve dump stability. Field observation of their growth performance has indicated that the mean grass height and root depth are 232 (+/- 74) cm and 46 (+/-5) cm, respectively, after three years and the below-ground root biomass is 474 (+/- 69) g m{sup -2}. The mechanical and hydrogeological actions of the grass roots have improved the shear strength properties of the dump material. Numerical modelling has shown that the roots of these grasses increase the factor of safety of the dump slope from 1.2 to 1.4 and thus play a substantial role in the maintenance of long-term stability.

  8. Stability of nuclear crater slopes in rock

    International Nuclear Information System (INIS)

    The United States Army Engineer Nuclear Cratering Group was established in 1962 to participate with the Atomic Energy Commission in a joint research and development program to develop nuclear engineering and construction technology. A major part of this research effort has been devoted to studies of the engineering properties of craters. The program to date has included field investigations of crater properties in various media over a broad range of chemical and nuclear explosive yields, studies of man-made and natural slopes, and studies directed toward the development of analytical and empirical methods of crater stability analysis. From this background, a general understanding has been developed of the effects of a cratering explosion on the surrounding medium and of physical nature of the various crater zones which are produced. The stability of nuclear crater slopes has been a subject of prime interest in the feasibility study being conducted for an Atlantic-Pacific sea-level canal. Based on experimental evidence assembled to date, nuclear crater slopes in dry dock and dry alluvium have an initially stable configuration. There have been five nuclear craters produced to date with yields of 0.4 kt or more on which observations are based and the initial configurations of these craters have remained stable for over seven years. The medium, yield, crater dimensions, and date of event for these craters are summarized. It is interesting to note that the Sedan Crater has been subjected to strong seismic motions from nearby detonations without adverse effects

  9. High slope waste dumps – a proven possibility

    Directory of Open Access Journals (Sweden)

    Igor Svrkota

    2013-11-01

    Full Text Available This paper is an overview of dumping operations on High Slope Waste Dump at Veliki Krivelj open pit copper mine, RTB Bor, Serbia. The High Slope Waste Dump in Bor is the highest single slope waste dump in the world with the slope height of 405 m. The paper gives the basics and limitations of the designed dumping technology, the redesigned technology, gives an overview of the 13 year long operation and gathered experiences and addresses the main issues of dumping operations in high slope conditions as well as the present condition of the High Slope Waste Dump.

  10. Slope stability monitoring from microseismic field using polarization methodology

    Directory of Open Access Journals (Sweden)

    Yu. I. Kolesnikov

    2003-01-01

    Full Text Available Numerical simulation of seismoacoustic emission (SAE associated with fracturing in zones of shear stress concentration shows that SAE signals are polarized along the stress direction. The proposed polarization methodology for monitoring of slope stability makes use of three-component recording of the microseismic field on a slope in order to pick the signals of slope processes by filtering and polarization analysis. Slope activity is indicated by rather strong roughly horizontal polarization of the respective portion of the field in the direction of slope dip. The methodology was tested in microseismic observations on a landslide slope in the Northern Tien-Shan (Kyrgyzstan.

  11. Stability of the slopes around nuclear power plants in earthquake

    International Nuclear Information System (INIS)

    The evaluation of the stability of the slopes around the buildings of nuclear power plants is important especially with respect to earthquakes. In this connection, the behavior of a slope up to its destruction and the phenomena of the destruction have been examined in the case of an earthquake by both experiment and numerical analysis. The purpose is to obtain the data for the establishment of a method for evaluating the seismic stability of a slope and of the slope design standards. The following results are described: the behavior of a slope and its destruction characteristics in the slope destruction experiment simulating the seismic coefficient method; the vibration of a slope and its destruction characteristics in vibration destruction experiment; the validity of the method of numerical simulation analysis and of stability evaluation for the slope destruction and the vibration destruction experiments, and quantitative destruction mechanism; the comparison of the various stability evaluation methods and the evaluation of seismic forces. (Mori, K.)

  12. Evaluation of Slope Assessment Systems for Predicting Landslides of Cut Slopes in Granitic and Meta-sediment Formations

    Directory of Open Access Journals (Sweden)

    Suhaimi Jamaludin

    2006-01-01

    Full Text Available In Malaysia, slope assessment systems (SAS are widely used in assessing the instability of slope or the probability of occurrence and the likely severity of landslides. These SAS can be derived based on either one particular approach or combination of several approaches of landslide assessments and prediction. This study overviews four slope assessment systems (SAS developed in Malaysia for predicting landslide at a large-scale assessments. They are the Slope Maintenance System (SMS, Slope Priority Ranking System (SPRS, Slope Information Management System (SIMS and the Slope Management and Risk Tracking System (SMART. An attempt is made to evaluate the accuracy of the SAS in predicting landslides based on slope inventory data from 139 cut slopes in granitic formation and 47 cut slopes in meta-sediment formation, which are the two most common rock/soil formations found in Malaysia. Based on this study, it was found that none of existing SAS is satisfactory in predicting landslides of cut slopes in granitic formation, for various reasons such as the use of hazard score developed from another country, insufficient data base, oversimplified approach and use of data base derived from different rock/soil formations. However for the case of cut slope in meta-sediment, the Slope Management and Risk Tracking System (SMART was found to be satisfactory with 90% prediction accuracy. The current database of SMART is largely based on meta-sediment formation.

  13. Erosion Protection for Soil Slopes Along Virginia's Highways

    OpenAIRE

    Jessee A. Scarborough; Filz, George M.; Mitchell, James K.; Thomas L. Brandon

    2000-01-01

    A survey of the state of practice for designing slope erosion control measures within VDOT's nine districts has been conducted. On the basis of the survey, it is clear that there are no specific design procedures currently in use within VDOT for dealing with slope erosion. VDOT designers generally try to limit erosion by diverting runoff from adjacent areas, controlling concentrated flows on slopes, and establishing vegetation on slopes as quickly as possible. In addition, the Federal Highway...

  14. The Key Technologies of Steep Rock Slope Protection

    OpenAIRE

    Hongliang Deng; Tingting Ni; Kaijiang Chen; Mingyan Zhu

    2013-01-01

    This study takes the steep slope of Qianlin Mountain in Beijing National Forest Park as an example. The job of engineering applications and comparative analysis are done as well as estimating the protection effect. Because of the complicated formation and geological conditions of the steep slope, accidents such as slope instability, collapsing are easier to happen. Therefore, the technology of the reinforcement and protection of steep slope are important. Even the methods are improper; it rem...

  15. Slope stability monitoring from microseismic field using polarization methodology

    OpenAIRE

    Kolesnikov, Yu. I.; Nemirovich-Danchenko, M. M.; Goldin, S. V.; V. S. Seleznev

    2003-01-01

    Numerical simulation of seismoacoustic emission (SAE) associated with fracturing in zones of shear stress concentration shows that SAE signals are polarized along the stress direction. The proposed polarization methodology for monitoring of slope stability makes use of three-component recording of the microseismic field on a slope in order to pick the signals of slope processes by filtering and polarization analysis. Slope activity is indicated by rather strong roughly horizontal polar...

  16. Evaluation of Slope Stability Performance in Different Methods

    OpenAIRE

    Abdoullah Namdar,; Azam Khodashenas Pelko

    2010-01-01

    The magnitude of liquefaction is changing respect to level of underground water, soil mechanical properties, time, direction and magnitude of forces. In this research work to understanding slope failure mechanism the limit equilibrium code employed to evaluating slope stability and assessing failure. The result revealed that thefailure of slope could be predicted if accurate slope behavior investigated. For increasing soil structure stability and loads mitigation this is essential of appropri...

  17. Western Ross Sea continental slope gravity currents

    Science.gov (United States)

    Gordon, Arnold L.; Orsi, Alejandro H.; Muench, Robin; Huber, Bruce A.; Zambianchi, Enrico; Visbeck, Martin

    2009-06-01

    Antarctic Bottom Water of the world ocean is derived from dense Shelf Water that is carried downslope by gravity currents at specific sites along the Antarctic margins. Data gathered by the AnSlope and CLIMA programs reveal the presence of energetic gravity currents that are formed over the western continental slope of the Ross Sea when High Salinity Shelf Water exits the shelf through Drygalski Trough. Joides Trough, immediately to the east, offers an additional escape route for less saline Shelf Water, while the Glomar Challenger Trough still farther east is a major pathway for export of the once supercooled low-salinity Ice Shelf Water that forms under the Ross Ice Shelf. The Drygalski Trough gravity currents increase in thickness from ˜100 to ˜400 m on proceeding downslope from ˜600 m (the shelf break) to 1200 m (upper slope) sea floor depth, while turning sharply to the west in response to the Coriolis force during their descent. The mean current pathway trends ˜35° downslope from isobaths. Benthic-layer current and thickness are correlated with the bottom water salinity, which exerts the primary control over the benthic-layer density. A 1-year time series of bottom-water current and hydrographic properties obtained on the slope near the 1000 m isobath indicates episodic pulses of Shelf Water export through Drygalski Trough. These cold (34.75) pulses correlate with strong downslope bottom flow. Extreme examples occurred during austral summer/fall 2003, comprising concentrated High Salinity Shelf Water (-1.9 °C; 34.79) and approaching 1.5 m s -1 at descent angles as large as ˜60° relative to the isobaths. Such events were most common during November-May, consistent with a northward shift in position of the dense Shelf Water during austral summer. The coldest, saltiest bottom water was measured from mid-April to mid-May 2003. The summer/fall export of High Salinity Shelf Water observed in 2004 was less than that seen in 2003. This difference, if real, may reflect the influence of the large iceberg C-19 over Drygalski Trough until its departure in mid-May 2003, when there was a marked decrease in the coldest, saltiest gravity current adjacent to Drygalski Trough. Northward transport of cold, saline, recently ventilated Antarctic Bottom Water observed in March 2004 off Cape Adare was ˜1.7 Sv, including ˜0.4 Sv of High Salinity Shelf Water.

  18. Regional method to assess offshore slope stability.

    Science.gov (United States)

    Lee, H.J.; Edwards, B.D.

    1986-01-01

    The slope stability of some offshore environments can be evaluated by using only conventional acoustic profiling and short-core sampling, followed by laboratory consolidation and strength testing. The test results are synthesized by using normalized-parameter techniques. The normalized data are then used to calculate the critical earthquake acceleration factors or the wave heights needed to initiate failure. These process-related parameters provide a quantitative measure of the relative stability for locations from which short cores were obtained. The method is most applicable to offshore environments of gentle relief and simple subsurface structure and is not considered a substitute for subsequent site-specific analysis. -from ASCE Publications Information

  19. Outerplanar graph drawings with few slopes

    CERN Document Server

    Knauer, Kolja; Walczak, Bartosz

    2012-01-01

    We consider straight-line outerplanar drawings of outerplanar graphs in which the segments representing edges are parallel to a small number of directions. We prove that Delta-1 directions suffice for every outerplanar graph with maximum degree Delta>=4. This improves the previous bound of O(Delta^5), which was shown for planar partial 3-trees, a superclass of outerplanar graphs. The bound is tight: for every Delta>=4 there is an outerplanar graph of maximum degree Delta which requires at least Delta-1 distinct edge slopes for an outerplanar straight-line drawing.

  20. Euthanasia, dying well and the slippery slope.

    Science.gov (United States)

    Allmark, P

    1993-08-01

    Arguments in favour of voluntary euthanasia tend to be put in utilitarian terms. This paper suggests an alternative, neo-Aristotelian argument justifying certain individual acts of both suicide and voluntary euthanasia. It goes on to examine the slippery slope arguments against legalizing euthanasia. It is suggested that such arguments cut both ways. However, the suggestion that we ought therefore to permit a social experiment in voluntary euthanasia is set alongside the Dutch experience. The latter seems to imply that if such experiments are to take place then great caution needs to be applied. PMID:8376654

  1. Seismic Stability of Reinforced Soil Slopes

    DEFF Research Database (Denmark)

    Tzavara, I.; Zania, Varvara; Tsompanakis, Y.; Psarropoulos, P.N.

    Over recent decades increased research interest has been observed on the dynamic response and stability issues of earth walls and reinforced soil structures. The current study aims to provide an insight into the dynamic response of reinforced soil structures and the potential of the geosynthetics...... to prevent the development of slope instability taking advantage of their reinforcing effect. For this purpose, a onedimensional (SDOF) model, based on Newmark’s sliding block model as well as a two-dimensional (plane-strain) dynamic finite-element analyses are conducted in order to investigate the...

  2. Transhumanism, medical technology and slippery slopes.

    Science.gov (United States)

    McNamee, M J; Edwards, S D

    2006-09-01

    In this article, transhumanism is considered to be a quasi-medical ideology that seeks to promote a variety of therapeutic and human-enhancing aims. Moderate conceptions are distinguished from strong conceptions of transhumanism and the strong conceptions were found to be more problematic than the moderate ones. A particular critique of Boström's defence of transhumanism is presented. Various forms of slippery slope arguments that may be used for and against transhumanism are discussed and one particular criticism, moral arbitrariness, that undermines both weak and strong transhumanism is highlighted. PMID:16943331

  3. 30 CFR 56.3130 - Wall, bank, and slope stability.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Wall, bank, and slope stability. 56.3130... Mining Methods § 56.3130 Wall, bank, and slope stability. Mining methods shall be used that will maintain wall, bank, and slope stability in places where persons work or travel in performing their...

  4. NOAA TIFF Image - 4m Bathymetric Slope of Slope for Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Bathymetric Slope of Slope GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off the...

  5. Water budgets of martian recurring slope lineae

    Science.gov (United States)

    Grimm, Robert E.; Harrison, Keith P.; Stillman, David E.

    2014-05-01

    Flowing water, possibly brine, has been suggested to cause seasonally reappearing, incrementally growing, dark streaks on steep, warm slopes on Mars. We modeled these Recurring Slope Lineae (RSL) as isothermal water flows in thin surficial layers driven by gravity and capillary suction, with input from sources in the headwall and loss to evaporation. The principal observables are flow duration and length. At 40% porosity, we find that flow thicknesses reaching saturation can be just 50 mm or so and freshwater RSL seasonally require 2-10 m3 of H2O per m of source headwall. Modeled water budgets are larger for brines because they are active for a longer part of each day, but this could be partly offset by lower evaporation rates. Most of the discharged water is lost to evaporation even while RSL are actively lengthening. The derived water volumes, while small, exceed those that can be supplied by annual melting of near-surface ice (0.2-2 m3/m for a 200-mm melt depth over 1-10 m height). RSL either tap a liquid reservoir startlingly close to the surface, or the actual water budget is several times smaller. The latter is possible if water never fully saturates RSL along their length. Instead, they would advance like raindrops on a window, as intermittent slugs of water that overrun prior parts of the flow at residual saturation. Annual recharge by vapor cold trapping might then be supplied from the atmosphere or subsurface.

  6. Drilling wastes management for Alaskas North Slope

    International Nuclear Information System (INIS)

    This paper reports on drilling wastes management for Alaska's North Slope. In the early 1980s the State of Alaska's Department of Environmental Conservation determined that drilling waste disposal practices at the oil fields on the North Slope were not adequately protecting the environment. New regulations were promulgated in october, 1987 that required improved containment of wastes and better monitoring of waste disposal sites. Industry and the state have been working together to develop methods that will meet the requirements of the new regulations and a number of these methods have been tried in the field over the past few years. The methods, including waste reduction, injection of drilling wastes, deep hole burial using permafrost for containment, shallow hole burial using permafrost for containment, and treatment of waste for use as construction material, are discussed in context with the status in the development of each technology, concerns for each technology that the state has, and regulatory schemes that have been developed for each technology

  7. High slope waste dumps – a proven possibility

    OpenAIRE

    Igor Svrkota; Radoje Pantović; Miodrag Žikić; Saša Stojadinović; Dejan Petrović

    2013-01-01

    This paper is an overview of dumping operations on High Slope Waste Dump at Veliki Krivelj open pit copper mine, RTB Bor, Serbia. The High Slope Waste Dump in Bor is the highest single slope waste dump in the world with the slope height of 405 m. The paper gives the basics and limitations of the designed dumping technology, the redesigned technology, gives an overview of the 13 year long operation and gathered experiences and addresses the main issues of dumping operations in high slope condi...

  8. Multi Rotor Uav at Different Altitudes for Slope Mapping Studies

    Science.gov (United States)

    Tahar, K. N.

    2015-08-01

    Most of consultation work only involves a small area, especially for slope mapping studies. The objective of this study is to evaluate the accuracy of slope mapping results from different altitudes at semi-undulated area and undulated area. Multi-rotor UAV is used as an instrument for data acquisition for this study. The images of slope were captured from five different altitudes in the same study area. All images were processed using photogrammetric software to produce digital elevation models and digital orthophoto. In this study, slope map from all different altitudes were identified and recorded for analysis purposes. It was found that the accuracy of slope is increase when altitude is increase. In conclusion, the condition of slope such as semi-undulated and undulated area did have an influence on the slope accuracy.

  9. ASPECTS OF DRIP IRRIGATION ON SLOPES

    Directory of Open Access Journals (Sweden)

    Oprea Radu

    2010-01-01

    Full Text Available Nowadays, water and its supply raise problems of strategic importance, of great complexity, being considered one of the keys to sustainable human development. Drip irrigation consists in the slow and controlled administration of water in the area of the root system of the plants for the purposes of fulfilling their physiological needs and is considered to be one of the variants of localized irrigation. Water is distributed in a uniform and slow manner, drop by drop, in a quantity and with a frequency that depend on the needs of the plant, thanks to the exact regulation of the water flow rate and pressure, as well as to the activation of the irrigation based on the information recorded by the tensiometer with regard to soil humidity. This method enables the exact dosage of the water quantity necessary in the various evolution stages of the plant, thus eliminating losses. By applying the irrigation with 5 liters of water per linear meter, at a 7 days interval, in the month of august, for a vine cultivated on a slope, in layers covered with black film and irrigated via dropping, soil humidity immediately after irrigation reaches its highest level, but within the limits of active humidity, on the line of the irrigation band. Three days later, the water content of the soil in the layer is relatively uniform, and, after this interval, it is higher in the points situated at the basis of the film. This technology of cultivation on slopes favors the accumulation, in the soil, of the water resulted from heavy rains and reduces soil losses as a result of erosion.

  10. Rapid drawdown in slopes and embankments

    Science.gov (United States)

    Pinyol, Núria M.; Alonso, Eduardo E.; Olivella, Sebastiã

    2008-05-01

    The rapid drawdown condition arises when submerged slopes experience a rapid reduction of the external water level. Classical procedures developed to determine the flow regime within the slope and the resulting stability conditions are reviewed in the paper. They are grouped in two classes: the "stress-based" undrained approach, recommended for impervious materials, and the flow approach, which is specified for rigid pervious materials (typically a granular soil). Field conditions often depart significantly from these simplified cases and involve materials of different permeability and compressibility arranged in a complex geometry. The drawdown problem is presented in the paper as a fully coupled flow-deformation problem for saturated/unsaturated conditions. Some fundamental concepts are first discussed in a qualitative manner and, later, explored in more detail in synthetic examples, solved under different hypotheses, including the classical approaches. Some design rules, which include a few fundamental parameters for the drawdown problem, have also been solved in a rigorous manner to illustrate the limitations of simplified procedures. A significant portion of the paper is devoted to the discussion of a comprehensive case history. In Shira, earth dam pore pressures were recorded at different points inside the embankment during a controlled drawdown. Predictions of four calculation procedures (instantaneous drawdown, pure flow, coupled flow-elastic, and coupled flow-elastoplastic, all of them for saturated/unsaturated conditions) are compared with measured pressure records. Only the coupled analysis provides a consistent and reasonable solution. The role of the different soil properties in explaining the phenomena taking place during drawdown is finally discussed.

  11. Nocturnal flow on a western Colorado slope

    International Nuclear Information System (INIS)

    The Department of Energy sponsored Atomspheric Studies in Complex Terrain (ASCOT) program has conducted a research program designed to increase our knowledge and understanding of terrain-dominated flows with specific emphasis on nocturnal flows within mountain valleys. ASCOT has sponsored both field studies and numerical modeling efforts to improve our understanding of the wind, temperature and turbulence structure of nocturnal drainage flows. One of the most recent ASCOT sponsored field studies involves a study within the Mesa Creek Basin in western Colorado to investigate the seasonal frequency of occurrence of drainage flows along the sloped surfaces and within the basin, and to evaluate the effect of the ambient meteorology on their development. The Mesa Creek Basin, situated on the north slope of the Grand Mesa, encompasses a roughly 10 x 20 km area that is approximately 30 km east of Grand Junction. The observational segment of the study was undertaken jointly by the Lawrence Livermore National Laboratory and the NOAA Wave Propagation Laboratory, and involved the operation of network of eight meteorological towers and a monostatic sodar within the Mesa Creek study area over a period of one year that extended from December 1988 through November 1989. These measurements were augmented by tethersonde observations to define the vertical wind and temperature structure during a few nights. The modeling portion of the study is being undertaken by Lawrence Livermore Laboratory using a three-dimensional prognostic boundary layer model to gain further insight into the dynamics of the seasonal variations and the effect of cloud cover on the development of the drainage flows. It is the purpose of this paper to present preliminary results form a numerical simulation done as part of this study. 4 refs., 7 figs

  12. Dendrogeomorphic approach to estimating slope retreat, Maxey Flats, Kentucky

    International Nuclear Information System (INIS)

    A dendrogeomorphic study of slope retreat was conducted at the Maxey Flats nuclear-waste disposal site in northeastern Kentucky. Tree roots exposed by surface lowering were used as an indicator of ground surface at the time of germination. The amount of lowering was measured and divided by tree-ring-determined tree age. Surface lowering and slope degradation rates were estimated for three slopes below waste-burial trenches and compared with data obtained from sediment troughs and erosion frames at the site. Mean rates of slope retreat ranged from 1.92 to 3.16 mm/yr. Sediment-trough results are two to three orders of magnitude less than dendrogeomorphic and erosion-frame estimates of slope degradation, which suggests that piping and solution-weathering processes may be important in slope degradation. Slope aspect and declivity may be important factors affecting retreat of slopes with a uniform lithology. Dendrogeomorphic techniques provide results comparable to those in the literature and offer a rapid method for estimating slope retreat that integrates slope processes over many years

  13. Design principles for optimizing an established survey slope monitoring system

    Scientific Electronic Library Online (English)

    N, Mphathiwa; F.T, Cawood.

    2014-06-01

    Full Text Available When slope angles are designed during open pit optimization, there is a risk factor applied in steepening the slopes. The steepening of slope angles has implications for the safety and economics of the mining operation. The steeper the slope angles, the greater the probability of slope failure. Alth [...] ough a slope failure will result in added costs, the challenge is to compile an accurate cost-benefit exercise optimizing the economic benefits of the project without exposing mine workers and equipment to unacceptable risk of rockfalls. A balance between the safety of the operation and the economics of the investment is therefore required. The ideal situation is to have a slope monitoring system that will predict slope failure by detecting any ground movement before the actual failure occurs. This early warning will allow the risk factor to be applied with a high degree of confidence, knowing that the risk will be adequately mitigated. The objective of this paper is to provide guidelines on how to design an optimal survey slope monitoring system. It is the authors' view that for a survey monitoring system to yield desirable results, it should adhere to survey principles such as working from the whole to part and consistently cross-checking. The case study used is Jwaneng Mine, and the design strategy outlined can be used as a guideline for developing a new slope monitoring system or to optimize an existing one.

  14. Model tests of geosynthetic reinforced slopes in a geotechnical centrifuge

    International Nuclear Information System (INIS)

    Geosynthetic-reinforced slopes and walls became very popular in recent years because of their financial, technical, and ecological advantages. Centrifuge modelling is a powerful tool for physical modelling of reinforced slopes and offers the advantage to observe the failure mechanisms of the slopes. In order to replicate the gravity induced stresses of a prototype structure in a geometrically 1/N reduced model, it is necessary to test the model in a gravitational field N times larger than that of the prototype structure. In this dissertation, geotextile-reinforced slope models were tested in a geotechnical centrifuge to identify the possible failure mechanisms. Slope models were tested by varying slope inclination, tensile strengths of the geotextiles, and overlapping lengths. Photographs of the geotextile reinforced slope models in flight were taken with a digital camera and the soil deformations of geotextile reinforced slopes were evaluated with Particle Image Velocimetry (PIV). The experimental results showed that failure of the centrifuge models initiated at midheight of the slope, and occurred due to geotextile breakage instead of pullout. The location of the shear surface is independent of the tensile strength of the geotextile; it is dependent on the shear strength of the soil. It is logical to see that the required acceleration of the centrifuge at slope failure was decreased with increasing slope inclination. An important contribution to the stability of the slope models was provided by the overlapping of the geotextile layers. It has a secondary reinforcement effect when it was prolonged and passed through the shear surface. Moreover, the location of the shear surface observed with PIV analysis exactly matches the tears of the retrieved geotextiles measured carefully after the centrifuge testing. It is concluded that PIV is an efficient tool to instrument the slope failures in a geotechnical centrifuge.(author)

  15. Calculation method of solar radiation incident upon slopes considering topography

    International Nuclear Information System (INIS)

    When radiation in a basin is calculated, slope inclination, slope orientation and topography of surroundings have to be taken into account. The method of approximation to topography by triangles proposed by Miura et al. is employed to take slope characteristics and topography of surroundings into account. Authors prepared 360 directions' shades altitudes, i.e. every degree of angle, for each triangle in advance, and used these shades' altitudes to calculate both direct radiation on a slope diffuse radiation taking topography of surroundings into account. And authors show how to estimate hourly direct and diffuse solar radiation from hourly horizontal global radiation and synthesize hourly slope global radiation on slopes

  16. Improvement parameters in dynamic compaction adjacent to the slopes

    Directory of Open Access Journals (Sweden)

    Elham Ghanbari

    2015-04-01

    Full Text Available Dynamic compaction is a cost-effective method commonly used for improvement of sandy soils. A number of researchers have investigated experimentally and numerically the improvement parameters of soils using dynamic compaction, such as crater depth, improvement depth, and radial improvement, however, these parameters are not studied for improvement adjacent to the slopes or trenches. In this research, four different slopes with different inclinations are modeled numerically using the finite element code ABAQUS, and impact loads of dynamic compaction are applied. The static factors of safety are kept similar for all trenches and determined numerically by application of gravity loads to the slope using strength reduction method (SRM. The analysis focuses on crater depth and improvement region which are compared to the state of flat ground. It can be observed that compacted area adjacent to the slopes is narrower and slightly away from the slope compared to the flat state. Moreover, crater depth increases with increase in slope inclination.

  17. Characterization of rock slopes through slope mass rating using 3D point clouds

    OpenAIRE

    Riquelme Guill, Adrián; Tomás Jover, Roberto; Abellán Fernández, Antonio

    2016-01-01

    Rock mass classification systems are widely used tools for assessing the stability of rock slopes. Their calculation requires the prior quantification of several parameters during conventional fieldwork campaigns, such as the orientation of the discontinuity sets, the main properties of the existing discontinuities and the geo-mechanical characterization of the intact rock mass, which can be time-consuming and an often risky task. Conversely, the use of relatively new remote sensing data for ...

  18. Characterization of the collagen component of cartilage repair tissue of the talus with quantitative MRI: comparison of T2 relaxation time measurements with a diffusion-weighted double-echo steady-state sequence (dwDESS)

    Energy Technology Data Exchange (ETDEWEB)

    Kretzschmar, M.; Hainc, N.; Studler, U. [University Hospital Basel, Department of Radiology, Basel (Switzerland); Bieri, O. [University Hospital Basel, Division of Radiological Physics, Basel (Switzerland); Miska, M. [University Hospital, Department of Orthopedics, Heidelberg (Germany); Wiewiorski, M.; Valderrabano, V. [University Hospital Basel, Department of Orthopedic Surgery, Basel (Switzerland)

    2015-04-01

    The purpose of this study was to characterize the collagen component of repair tissue (RT) of the talus after autologous matrix-induced chondrogenesis (AMIC) using quantitative T2 and diffusion-weighted imaging. Mean T2 values and diffusion coefficients of AMIC-RT and normal cartilage of the talus of 25 patients with posttraumatic osteochondral lesions and AMIC repair were compared in a cross-sectional design using partially spoiled steady-state free precession (pSSFP) for T2 quantification, and diffusion-weighted double-echo steady-state (dwDESS) for diffusion measurement. RT and cartilage were graded with modified Noyes and MOCART scores on morphological sequences. An association between follow-up interval and quantitative MRI measures was assessed using multivariate regression, after stratifying the cohort according to time interval between surgery and MRI. Mean T2 of the AMIC-RT and cartilage were 43.1 ms and 39.1 ms, respectively (p = 0.26). Mean diffusivity of the RT (1.76 ?m{sup 2}/ms) was significantly higher compared to normal cartilage (1.46 ?m{sup 2}/ms) (p = 0.0092). No correlation was found between morphological and quantitative parameters. RT diffusivity was lowest in the subgroup with follow-up >28 months (p = 0.027). Compared to T2-mapping, dwDESS demonstrated greater sensitivity in detecting differences in the collagen matrix between AMIC-RT and cartilage. Decreased diffusivity in patients with longer follow-up times may indicate an increased matrix organization of RT. (orig.)

  19. Heat Transfer Energy Balance Model of Single Slope Solar Still

    OpenAIRE

    Kiam Beng Yeo; Cheah Meng Ong; Kenneth Tze Kin Teo

    2014-01-01

    Single slope solar still absorbs the thermal energy from sunlight to distillate polluted water into clean water in an enclosed space. Principal of heat transfer and energy balance were the governing equations for the operation of single slope solar still. A mathematical model was developed to express these thermodynamics behaviours. In the model, critical parameters had been identified, such as slope angle of glass cover, mass of water in basin and wind speed. Simulation had been carried out ...

  20. Analysis of hydrological processes in unstable clayey slopes

    OpenAIRE

    Bogaard, T. A.

    2001-01-01

    In slope stability research a ground water level increase is often the critical factor for failure. High ground water levels (or more properly stated: high pore water pressures) reduce the internal strength of the slope. It is recognised for quite some time that fast infiltration of precipitation towards the (perched) ground water table can induce high pore pressures and thus instability within formerly stable slopes. However, deeper located landslides are affected on the lo...

  1. Slope Stability Analysis Using Limit Equilibrium Method in Nonlinear Criterion

    OpenAIRE

    Hang Lin; Wenwen Zhong; Wei Xiong; Wenyu Tang

    2014-01-01

    In slope stability analysis, the limit equilibrium method is usually used to calculate the safety factor of slope based on Mohr-Coulomb criterion. However, Mohr-Coulomb criterion is restricted to the description of rock mass. To overcome its shortcomings, this paper combined Hoek-Brown criterion and limit equilibrium method and proposed an equation for calculating the safety factor of slope with limit equilibrium method in Hoek-Brown criterion through equivalent cohesive strength and the fric...

  2. Research on the Slope Protection Mechanism of Roots

    OpenAIRE

    Juan Wan; Henglin Xiao; Jun He; Lihua Li

    2013-01-01

    This study aims to investigate the slope protection mechanism of roots. In ecological slope protection, plant roots can fix soil and protect slop through biological and mechanical action. However, previous studies on the slope protection mechanism are still not deep enough and inadequate. By taking four kinds of typical plant roots along Wu-Shen Expressway as the research object, through the indoor tensile test and root morphology observation analysis, the tensile strength and ultimate tensio...

  3. Three-dimensional kinematic controls on rock slope stability conditions

    OpenAIRE

    Brideau, Marc-Andre

    2010-01-01

    This thesis investigates the three-dimensional influence of discontinuity sets and topography on kinematics of rock slope stability and failure mechanisms. A field data collection methodology was developed to provide the inputs to a slope stability investigation that utilises three-dimensional geometric, limit equilibrium and distinct element codes. Conceptual slope geometries in addition to three case studies are employed to evaluate the influence of discontinuity set orientation and lateral...

  4. Impact Analysis of Blasting Vibration on the Slope and Dump

    OpenAIRE

    Zhang(?, Zhang, ?); Li Gang Yan; Xu Yuan

    2014-01-01

    As known that the blasting on the slope is very dangerous in the exploration of the mine andneeds complex analysis and calculation on the slope and dump. In the study it adopts the regression method in the analysis of important parameters of the vibration experiments of iron ore stope which influence the stability of slope and vibration velocity of mine blasting, vibration acceleration, etc., it makes the analysis of power spectrum and dynamic response. Thr...

  5. Slope Stability and Exceptional Divisors of High Genus

    OpenAIRE

    Panov, Dmitri; Ross, Julius

    2007-01-01

    We study slope stability of smooth surfaces and its connection with exceptional divisors. We show that a surface containing an exceptional divisor with arithmetic genus at least two is slope unstable for some polarisation. In the converse direction we show that slope stability of surfaces can be tested with divisors, and prove that for surfaces with non-negative Kodaira dimension any destabilising divisor must have negative self-intersection and arithmetic genus at least two...

  6. The Key Technologies of Steep Rock Slope Protection

    Directory of Open Access Journals (Sweden)

    Hongliang Deng

    2013-07-01

    Full Text Available This study takes the steep slope of Qianlin Mountain in Beijing National Forest Park as an example. The job of engineering applications and comparative analysis are done as well as estimating the protection effect. Because of the complicated formation and geological conditions of the steep slope, accidents such as slope instability, collapsing are easier to happen. Therefore, the technology of the reinforcement and protection of steep slope are important. Even the methods are improper; it remains a significant security risk. Given the limitations of a variety of protection technologies, a new method called spray-anchor technology mixed flexible protection is proposed.

  7. Distinct Element Modelling of Mahabaleshwar Road Cut Hill Slope

    OpenAIRE

    Ashutosh Kainthola; P. K. Singh; A. B. Wasnik; Singh, T.N.

    2012-01-01

    Reliable estimates of slope stability are essential for safe design and planning of road cut hill slopes which accommo-date a number of tourist destinations around the world. The failure of cut slopes along these hills puts human life in grave danger and it is also disastrous for the economy. In the present study, a section of 100 m high jointed basalt hill slope has been analyzed numerically in a distinct element code, which is apt for simulating the behavior for jointed rock. The analysis w...

  8. Perceptibility of double-slope reverberation decays

    Science.gov (United States)

    Knight, Derrick P.; Shimizu, Yasushi; Torres, Rendell R.

    2002-11-01

    No concert hall has a perfectly diffuse field, although many are close enough that their decay is perceived as linear. In recent years, concert hall acousticians have taken steps to ensure more exaggerated double-sloped (nonlinear) decays in their concert halls by using coupled volumes. Some acousticians feel that a coupled volume gives a hall a balance between clarity (subjectively speaking) and reverberance. However, there have been no studies done to determine when a nonlinear decay becomes perceptibly different from a linear decay. This work seeks to identify the threshold of perception for nonlinear decays. Nonlinear impulse responses of different lengths are generated by first computing uncoupled impulse responses of a concert hall and a coupled volume in CATT-Acoustic. The two linear impulse responses are convolved in matlab. These convolved impulse responses are manipulated to systematically vary the degree of nonlinear decay. The various nonlinear impulse responses are then convolved with anechoic signals with different temporal characteristics and presented to listeners for evaluation. From these evaluations, a criteria is derived to determine when a nonlinear decay becomes audibly different from a linear decay to a listener for various representative signals.

  9. Design of Overall Slope Angle and Analysis of Rock Slope Stability of Chadormalu Mine Using Empirical and Numerical Methods

    OpenAIRE

    Mahdi Rasouli Maleki; Mohammad Mahyar; Kambiz Meshkabadi

    2011-01-01

    In engineering projects associated with rock mechanic science like open pit mines, assessment and slope stability of mine walls is one of the important performance in generate of these structures. Estimating and knowledge of stable slope angle is one of main parts that should be occurring to special attention in open pit mines studies phase. Considering the importance of economic costs in mining issues, the need for appropriate design slope angle that can cause an adverse minimize project cos...

  10. Slope-stability analysis and creep susceptibility of Quaternary sediments on the northeastern United States continental slope

    Science.gov (United States)

    Booth, James S.; Silva, Armand J.; Jordan, Stephen A.

    1984-01-01

    The continental slope off the northeastern United States is a relatively steep, morphologically complex surface which shows abundant evidence of submarine slides and related processes. Because this area may be developed by the petroleum industry, questions arise concerning the potential for further slope failures or unacceptable deformations and the conditions necessary to cause such instabilities. Accordingly, a generalized analysis of slope stability and the stress—strain—time-dependent behavior of the sediments is being conducted.

  11. Stability Analysis of Cut Slopes Using Continuous Slope Mass Rating and Kinematic Analysis in Rudraprayag District, Uttarakhand

    OpenAIRE

    R. K. Umrao; Singh, R.; Ahmad, M.; Singh, T.N.

    2011-01-01

    In mountain terrains of Himalaya, road and highway networks play a vital role in remote areas for transportation, public network and all kind of socio-economic activities. The stability of rock slopes along the roads and highways is a major concern in these hilly regions. Any kind of slope failure may lead to disruption in traffic, loss of properties and lives/injuries as well as environmental degradation. The unplanned excavations of rock slopes for construction or widening purposes may unde...

  12. Small scale tests on the progressive retreat of soil slopes

    Science.gov (United States)

    Voulgari, Chrysoula; Utili, Stefano; Castellanza, Riccardo

    2015-04-01

    In this paper, the influence due to the presence of cracks on the morphologic evolution of natural cliffs subject to progressive retreat induced by weathering is investigated through small scale laboratory tests. Weathering turns hard rocks into soft rocks that maintain the structure of the intact rocks, but are characterised by higher void ratios and reduced bond strengths; soft rocks are transformed into granular soils generally called residual soils. A number of landslides develop in slopes due to weathering which results in the progressive retrogression of the slope face and the further degradation within the weathering zone. Cracks, that are widely present, can be a result of weathering and they can cause a significant decrease in their stability, as they provide preferential flow channels which increase the soil permeability and decrease the soil strength. The geological models employed until now are mainly empirical. Several researchers have tried to study the stability of slopes through experimental procedures. Centrifuge modelling is widely used to investigate the failure of slopes. Small scale tests are also an important approach, in order to study the behaviour of a slope under certain conditions, such as the existence of water, as they allow the observation of the infiltration processes, the movement of the weathering front, deformation and failure. However, the deformation response of a slope subject to weathering is not yet thoroughly clarified. In this work, a set of experiments were conducted to investigate weathering induced successive landslides. Weathering was applied to the slope model by wetting the slope crest through a rainfall simulator device. The moisture content of the soil during the tests was monitored by soil moisture sensors that were buried inside the slope model. High resolution cameras were recording the behaviour of the slope model. GeoPIV was used to analyse the frames and obtain the deformations of the slope model during the tests. After a short time of rainfall, vertical cracks appear in the slope model and significant vertical deformations start to occur around the crack, until the first failure is reached, the procedure carries on until a second failure is observed. Experimental results indicate that there is a strong connection between moisture content and the occurrence of a landslide. A prediction model of slope failures can be introduced based on the observed moisture content response of the slope models. KEYWORDS: slopes, cracks, landslide, weathering, small scale test

  13. A complementary mild-slope equation derived using higher-order depth function for waves obliquely propagating on sloping bottom

    Science.gov (United States)

    Hsu, Tai-Wen; Lin, Ta-Yuan; Wen, Chih-Chung; Ou, Shan-Hwei

    2006-08-01

    In this paper a complementary mild-slope equation (CMSE) is derived in order to investigate the transformation of progressive waves obliquely propagating over the sloping bottom more realistically. We introduce a new depth function which includes the wave refraction and the influence of the bottom slope ?, perturbed to the second-order in the integral equation. A new depth-integrated mild-slope equation is derived, by using the above mentioned depth function, to model a time-harmonic motion of small amplitude waves in varying water depth. The simulated results reveal that the proposed model provides a significant improvement in the calculation of the wavenumber and the group velocity at different bottom slopes. With the increasing bottom slope, the discrepancies in the reflection coefficient of Bragg scattering between the analytical solution and the one calculated from the conventional mild-slope equation (MSE) and the modified MSE (MMSE) are seen to steadily increase. The group velocity of the waves, when compared with the conventional MSE and MMSE, also shows its dependence on the bottom slope and wave propagating angle. The present model is observed to be quite efficient in taking into account the effect of steeper bottom slope.

  14. Analysis of one gravitational slope cycle

    Science.gov (United States)

    Palis, Edouard; Lebourg, Thomas; Vidal, Maurin; Tric, Emmanuel

    2015-04-01

    Since about twenty years of studies on landslides, we realized the role and subtle interactions that existed between the structural complexity, masses dynamics and complex internal circulation of fluids. The La Clapière DSL (Deep-Seated Landslide) is now very well known by the scientific community (volume, impact, challenges, observations...), but this mass of knowledge, has not yet been compiled nor looked through a coupled analysis of its spatial and temporal variability. Since 2007, a will to share and access to uniform data was set up by the Versant Instabilities Multidisciplinary Observatory (OMIV, National Service of French Observation (SNO)). This observatory (with associated laboratories) allowed the installation of permanent and autonomous measuring stations: GPS, meteorology, seismology, water chemistry sources. For two years now, a permanent electrical tomography device is installed at the bottom of the slope to complement the current monitoring system, and allowed a deeper understanding of the physical changes in the massif. The analysis of these data allows to observe different dynamic regimes, as well as different responses to external factors: instantaneous, delayed, long-term variability. The purpose of this synthesis study is to analyze the temporal and spatial evolution of the electrical resistivity, displacement and hydrometeors for one year cycle (November 2012 to November 2013). Thus, a qualitative and statistical approach by clusters, principal component analysis (PCA), and temporal pseudo-3D of these variables was established. This new statistical study also explains the major role of the fault and the base of the landslide, as well as the chronology of the water flow in the massif, allowing a better understanding of the complex and uneven in time dynamic in this area.

  15. Hydrologic design for riprap on embankment slopes

    International Nuclear Information System (INIS)

    Waste impoundments for uranium tailings and other hazardous substances are often protected by compacted earth and clay, covered with a layer of loose rock (riprap). The report outlines procedures that could be followed to design riprap to withstand forces caused by runoff resulting from extreme rainfall directly on the embankment. The Probable Maximum Precipitation for very small areas is developed from considerations of severe storms of short duration at mid-latitudes. A two-dimensional finite difference model is then used to calculate the runoff from severe rainfall events. The procedure takes into account flow both beneath and above the rock layer and approximates the concentration in flow which could be caused by a non-level or slumped embankment. The sensitivity to various assumptions, such as the shape and size of the rock, the thickness of the layer, and the shape of the embankment, suggests that peak runoff from an armored slope could be attenuated with proper design. Frictional relationships for complex flow regimes are developed on the basis of flow through rock-filled dams and in mountain streams. These relationships are tested against experimental data collected in laboratory flumes; the tests provide excellent results. The resulting runoff is then used in either the Stephenson or safety factor method to find the stable rock diameter. The rock sizes determined by this procedure for a given flow have been compared with data on the failure of rock layers in experimental flumes, again with excellent results. Computer programs are included for implementing the method. 15 refs., 21 figs., 9 tabs

  16. DESIGN INFORMATION REPORT: PROTECTION OF WASTEWATER LAGOON INTERIOR SLOPES

    Science.gov (United States)

    A problem common to many wastewater treatment and storage lagoons is erosion of the interior slopes. Erosion may be caused by surface runoff and wind-induced wave action. The soils that compose the steep interior slopes of lagoons are especially susceptible to erosion and slumpin...

  17. Investigation of Wetting Pattern Dimensions on Sloping Lands

    Directory of Open Access Journals (Sweden)

    A. Mohammadi

    2014-02-01

    Full Text Available To study the effects of irrigation durations and land slopes on wetting pattern dimensions, some experiments were performed using an emitter with constant discharge of 4 liters per hour by 2, 4, and 6 hours irrigation durations. Experiments were conducted on lands with the slopes of 0, 5, 15 an 25 percent, with silty loam soil texture in 3 replications in Fathali region, Mogan plain, Iran. Results showed that increasing the land slope caused an increment in wetting pattern dimensions and bulk, in constant irrigation durations. When slope increased, the depth of infiltrated water along the emitter had a little decrease which wasn’t significant. The upstream and downstream components of wetting pattern were symmetrical on 0 percent slope but not on steep lands. So, optimizing the water use, which is saved in the soil, depends on the land slope and the crop should be planted 10 to 25 centimeters away from the dripper. The investigation of soil moisture distribution on wetting pattern in slope lands showed that contrary to the flat lands the main part of the moisture is accumulated in lower part of the emitter, and wetting pattern in these sloping lands was larger than in flat lands.

  18. Culture of Sharing: North Slope Leaders Forge Trail into Future

    Science.gov (United States)

    Patkotak, Elise Sereni

    2010-01-01

    To create a strong local economy, the community needs a workforce. In Native communities, the workforce should be grounded in the local culture and values. On the North Slope of Alaska, this has long been a goal of leaders. To achieve this goal, North Slope leaders came together February 2010 in Barrow, Alaska, for the "Tumitchiat" Leadership…

  19. Slope spectrum variation in a simulated loess watershed

    Science.gov (United States)

    Li, Fayuan; Tang, Guoan; Wang, Chun; Cui, Lingzhou; Zhu, Rui

    2015-07-01

    A simulated loess watershed, where the loess material and relief properly represent the true loess surface, is adopted to investigate the variation in slope spectrum with loess watershed evolution. The evolution of the simulated loess watershed was driven by the exogenetic force of artificial rainfall. For a period of three months, twenty artificial rainfall events with different intensities and durations were carried out. In the process, nine DEM data sets, each with 10 mm grid resolution, were established by the method of close-range photogrammetry. The slope spectra were then extracted from these DEMs. Subsequent series of carefully designed quantitative analyses indicated a strong relationship between the slope spectrum and the evolution of the simulated loess watershed. Quantitative indices of the slope spectrum varied regularly following the evolution of the simulated loess watershed. Mean slope, slope spectrum information entropy (H), terrain driving force (T d ), Mean patch area (AREA_MN), Contagion Index (CONTAG), and Patch Cohesion Index (COHESION) kept increasing following the evolution of the simulated watershed, while skewness (S), Perimeter-Area Fractal Dimension (PAFRAC), and Interspersion and Juxtaposition Index (IJI) represented an opposite trend. All the indices changed actively in the early and active development periods, but slowly in the stable development periods. These experimental results indicate that the time series of slope spectra was able to effectively depict the slope distribution of the simulated loess watershed, thus presenting a potential method for modeling loess landforms.

  20. RMS slope of exponentially correlated surface roughness for radar applications

    DEFF Research Database (Denmark)

    Dierking, Wolfgang

    2000-01-01

    In radar signature analysis, the root mean square (RMS) surface slope is utilized to assess the relative contribution of multiple scattering effects. For an exponentially correlated surface, an effective RMS slope can be determined by truncating the high frequency tail of the roughness spectrum...

  1. HIRESSS: a physically based slope stability simulator for HPC applications

    OpenAIRE

    Rossi, G.; Catani, F.; Leoni, L; Segoni, S.; Tofani, V.

    2013-01-01

    HIRESSS (HIgh REsolution Slope Stability Simulator) is a physically based distributed slope stability simulator for analyzing shallow landslide triggering conditions in real time and on large areas using parallel computational techniques. The physical model proposed is composed of two parts: hydrological and geotechnical. The hydrological model receives the rainfall data as dynamical input and provi...

  2. Behavior analysis by model slope experiment of artificial rainfall

    Directory of Open Access Journals (Sweden)

    M. C. Park

    2015-06-01

    Full Text Available In this study, we performed a model slope experiment with rainfall seepage, and the results were compared and verified with the unsaturated slope stability analysis method. In the model slope experiment, we measured the changes in water content and matric suction due to rainfall seepage, and determined the time at which the slope failure occurred and the shape of the failure. In addition, we compared and verified the changes in the factor of safety and the shape of the failure surface, which was calculated from the unsaturated slope stability analysis with the model experiment. From the results of experiment and analysis, it is concluded that the unsaturated slope stability analysis can be used to accurately analyze and predict rainfall-induced slope failure. It is also concluded that in seepage analysis, setting the initial conditions and boundary conditions is very important. If engineers will use the measured pore water pressure or matric suction, the accuracy of analysis can be enhanced. The real-time monitoring system of pore water pressure or matric suction can be used as a warning of rainfall-induced slope failure.

  3. Slope Stability of Geosynthetic Clay Liner Test Plots

    Science.gov (United States)

    Fourteen full-scale field test plots containing five types of geosynthetic clay liners (GCLs) were constructed on 2H:IV and 3H:IV slopes for the purpose of assessing slope stability. The test plots were designed to simulate typical final cover systems for landfill. Slides occurr...

  4. Handling Correlations between Covariates and Random Slopes in Multilevel Models

    Science.gov (United States)

    Bates, Michael David; Castellano, Katherine E.; Rabe-Hesketh, Sophia; Skrondal, Anders

    2014-01-01

    This article discusses estimation of multilevel/hierarchical linear models that include cluster-level random intercepts and random slopes. Viewing the models as structural, the random intercepts and slopes represent the effects of omitted cluster-level covariates that may be correlated with included covariates. The resulting correlations between…

  5. DOWNWARD SLOPING DEMAND CURVES FOR STOCK AND LEVERAGE

    Directory of Open Access Journals (Sweden)

    Liem Pei Fun

    2006-01-01

    Full Text Available This research attempts to investigate the effect of downward sloping demand curves for stock on firms' financing decisions. For the same size of equity issuance, firms with steeper slope of demand curves for their stocks experience a larger price drop in their share price compare to their counterparts. As a consequence, firms with a steeper slope of demand curves are less likely to issue equity and hence they have higher leverage ratios. This research finds that the steeper the slope of demand curve for firm's stock, the higher the actual leverage of the firm. Furthermore, firms with a steeper slope of demand curves have higher target leverage ratios, signifying that these firms prefer debt to equity financing in order to avoid the adverse price impact of equity issuance on their share price.

  6. Application of distinct element method of toppling failure of slope

    International Nuclear Information System (INIS)

    The authors have pointed out, in the latest report, that DEM (Distinct Element Method) seems to be a very helpful numerical method to examine the stability of fissured rock slopes, in which toppling failure would occur during earthquakes. In this report, the applicability of DEM for such rock slopes is examined through the following comparisons between theoretical results and DEM results, referring Voegele's works (1982): (1) Stability of one block on a slope. (2) Failure of a rock block column composed of 10 same size rectangular blocks. (3) Cable force required to make a slope stable. Through above 3 comparisons, it seems that DEM give the reasonable results. Considering that these problems may not be treated by the other numerical methods such as FEM and so on, so DEM seems to be a very useful method for fissured rock slope analysis. (author)

  7. Slope of smooth rational curves in a Fano manifold

    CERN Document Server

    Hwang, Jun-Muk; Lee, Yongnam

    2010-01-01

    Ross and Thomas introduced the concept of slope stability to study K-stability, which has conjectural relation with the existence of constant scalar curvature metric. This paper presents a study of slope stability of Fano manifolds with respect to smooth curves. The question turns out to be easy for curves of genus $\\geq 1$ and the interest lies in the case of smooth rational curves. Our main result says that a Fano manifold $X$ with the anticanonical polarization is slope semistable with respect to any free smooth rational curve, and slope stable with respect to any smooth rational curve $Z$ of anticanonical degree $\\geq 3$, unless $X$ is the projective space and $Z$ is a line. Also we prove that a Fano threefold $X$ with Picard number 1 is slope stable with respect to any smooth rational curve unless $X$ is the projective space.

  8. Wave run-up on permeable fixed reveted slopes

    Directory of Open Access Journals (Sweden)

    I.G. Kantardgi

    2014-10-01

    Full Text Available A numerical model of surface wave movement and water filtration in saturated-unsaturated porous medium has been developed. The model can be used to define the parameters of the wave run-up on the slope protected with a permeable fixed layer. The model is applied to determine positions of the free wave surface at the different times, including such parameters as the height of wave run-up and wave run-down on the slope. In addition, both flow velocity field in the upper protected layer and moisture distribution in the soil body of the slope were defined. The model is verified with the results of the published large-scale tests that have been conducted at Technical University Braunschweig in the wave flume with the slopes protected according to Elastocoast technology. The numerical model can be applied to calculate the run-up of extreme waves on protected engineering and beach slopes in natural conditions.

  9. Slope mass rating and kinematic analysis of slopes along the national highway-58 near Jonk, Rishikesh, India

    Directory of Open Access Journals (Sweden)

    Tariq Siddique

    2015-10-01

    Full Text Available The road network in the Himalayan terrain, connecting remote areas either in the valleys or on the hill slopes, plays a pivotal role in socio-economic development of India. The planning, development and even maintenance of road and rail networks in such precarious terrains are always a challenging task because of complexities posed by topography, geological structures, varied lithology and neotectonics. Increasing population and construction of roads have led to destabilisation of slopes, thus leading to mass wasting and movement, further aggravation due to recent events of cloud bursts and unprecedented flash floods. Vulnerability analysis of slopes is an important component for the “Landslide Hazard Assessment” and “Slope Mass Characterisation” guide planners to predict and choose suitable ways for construction of roads and other engineering structures. The problem of landslides along the national highway-58 (NH-58 from Rishikesh to Devprayag is a common scene. The slopes along the NH-58 between Jonk and Rishikesh were investigated, which experienced very heavy traffic especially from March to August due to pilgrimage to Kedarnath shrine. On the basis of slope mass rating (SMR investigation, the area falls in stable class, and landslide susceptibility score (LSS values also indicate that the slopes under investigation fall in low to moderate vulnerability to landslide. More attentions should be paid to the slopes to achieve greater safe and economic benefits along the highway.

  10. Influence of slope steepness on soil erosion modelling with RUSLE, measured with rainfall simulations on subalpine slopes.

    Science.gov (United States)

    Tresch, Simon; Meusburger, Katrin; Alewell, Christine

    2015-04-01

    The topographical factor LS are one of the main factors for soil erosion modelling approaches within the RUSLE environment. There exists a large variety of different S-factors, for the most used soil erosion modelling environment, which have highly significant influences on the calculated erosion values. All existing S-factors have only been derived from gently slope inclinations (up to 32 %). Particularly in Switzerland, many cultivated areas are steeper than these critical values. Therefore, there exists a research gap for water soil erosion modelling of slopes beyond this slope inclinations. For the first time rainfall simulation could be made on very steep subalpine slopes (Uri, CH) with a portable field hybrid rainfall simulator. 18 plot measurements on transects ranging from 20 - 90 % slope steepness, were used for a qualitative assessment of the most suitable S-factors for steep subalpine slopes. The collected sediment and runoff amounts indicated a highly significant correlation between the soil loss, runoff and slope steepness. It was possible to make a first selection of an S-factor for slopes above the critical 25 % steepness. Additionally, the C-factor could be extracted from a supervised digital image analysis in ArcGIS.

  11. Biomechanics and Physiology for Propelling Wheelchair Uphill Slope.

    Science.gov (United States)

    Hashizume, Tsutomu; Kitagawa, Hiroshi; Lee, Hokyoo; Ueda, Hisatoshi; Yoneda, Ikuo; Booka, Masayuki

    2015-01-01

    A vertical slope of sidewalks significantly inhibits to the mobility of manual wheelchair users in their daily life. International guidelines of the vertical slope are specified approximately 4% or 5% (1:20) gradient or less as preferred, and allow 8.3% (1:12) as its maximum when it is impossible. Relevant research of the physical strain for wheelchair users with pushing on slopes, and the validity assessment of slope guidelines have been investigated. However, the analysis for the effect of a slope distance and their transient performance are still remained. The purpose of this study is to clarify the physiological and biomechanical characteristics of manual wheelchair users that propelling a wheelchair on an uphill slope. We measured these data by a metabolic analysis system, a heart rate monitor system and an instrumented wheelchair wheel. Sixteen unimpaired subjects (non-wheelchair users) were examined to investigate the effect of a long slope with 120m distance and 8% gradient. And five wheelchair users with cervical cord injury were examined to evaluate the influence of different gradients (5%, 6.7%, 8.3%, 10% and 12.5%) with 3m length in laboratory. Our experimental results of the long slope showed that wheelchair propulsion velocity and power increased considerably at the beginning of the slope where the peak mean value of them were 0.96 m/s and 70.8W and they decreased linearly to 0.55m/s and 33.6W at final interval. A mean oxygen uptake and heart rate were increased as the distance increased and their results indicated the extremely high exercise intensity at a final interval that were 1.2liter /min and 152bpm. While wheelchair pushing cadence reduced after an initial interval, mean of strokes per10m increased to compensate the decrease of upper limb's power. The results of different gradients indicated that the normalized power of subjects with cervical cord injury was significant difference between each subject in the ability to climb a slope. Mean normalized power were 0.23W/kg on a 5% slope, 0.24W/kg on 6.7%, and 0.26W/kg on 8.3% respectively. Based on these findings, we examined the relationship between the theoretical normalized power and the lowest velocity to climb a slope, and we might indicate the ability to push on an uphill slope for the persons with manual wheelchair user. PMID:26294512

  12. Management of the Nkomati Mine crusher slope failure

    Scientific Electronic Library Online (English)

    R., Armstrong; K., Moletsane.

    2014-10-01

    Full Text Available Due to limited available level ground, Nkomati Nickel Mine cut a weathered rock slope at the base of a mountain spur in order to create a platform for construction of the primary crusher plant and run-of-mine stockpiles. As space is limited around the mining area, ore processing at Nkomati is based [...] on a high reliability of flow of material through the crusher plant, with minimal usage of other and larger designed stockpiles. Evidently, any crusher plant shutdown will render the mine as a whole unproductive and put excessive strain on the medium- to long-term large ore stockpiles, the deposition rates for which are restricted by founding material consolidation requirements. At the onset of the 2012 rainy season, movement was identified on the slope monitoring system and cracks developed on the slope. After a minor failure on the crusher slope an assessment of the slope stability was conducted and a slope management plan recommended, which included deployment of real-time monitoring. An evaluation of the conditions leading to instability was conducted and the likely causes for the failure identified. A full evaluation of the slope monitoring, rainfall, and mining conditions was undertaken and movement triggers were determined. This paper describes the events leading to the development of the failure and the evaluation of the monitoring data to determine a management plan for the failure that allowed for minimal shutdowns of the primary crusher.

  13. Geotechnical characteristics and slope stability in the Gulf of Cadiz

    Science.gov (United States)

    Lee, H.; Baraza, J.

    1999-01-01

    Sedimentological and geotechnical analyses of thirty-seven core samples from the Gulf of Cadiz continental margin were used to define the regional variability of sediment properties and to assess slope stability. Considering the sediment property data set as a whole, there is an association between grain size, plasticity and water content. Any one of these properties can be mapped regionally to provide an indication of the dominant surface sediment lithology. Based on static sediment strength, a simplified slope stability analysis showed that only steep slopes (> 16??for even the most vulnerable sediment) can fail under static loading conditions. Accordingly, transient loads, such as earthquakes or storms, are needed to cause failure on more moderate slopes. A regional seismic slope stability analysis of the Cadiz margin was performed based on detailed geotechnical testing of four gravity core samples. The results showed that the stability of these slopes under seismic loading conditions depends upon sediment density, the cyclic loading shear strength, the slope steepness, and the regional seismicity. Sediment density and cyclic loading shear strength are dependent upon water content, which can act as a proxy for plasticity and texture effects. Specifically, Sediment in the water content range of 50-56% is most vulnerable to failure under cyclic loading within the Cadiz margin. As a result, for a uniform seismicity over the region, susceptibility to failure during seismic loading conditions increases with increasing slope steepness and is higher if the sediment water content is in the 50-56% range than if it is not. The only sampled zone of failure on the continental slope contains sediment with water content in this critical range. Storm-wave-induced instability was evaluated for the continental shelf. The evaluation showed that a storm having hundreds of waves with a height in the range of 16 m might be capable of causing failure on the shelf. However, no sediment failures were observed on the shelf that might have been caused by this mechanism.

  14. Development of a new generation of optical slope measuring profiler

    International Nuclear Information System (INIS)

    We overview the results of a broad US collaboration, including all DOE synchrotron labs (ALS, APS, BNL, NSLS-II, LLNL, LCLS), major industrial vendors of x-ray optics (InSync, Inc., SSG Precision Optronics-Tinsley, Inc., Optimax Systems, Inc.), and with active participation of HBZ-BESSY-II optics group, on development of a new generation slope measuring profiler - the optical slope measuring system (OSMS). The desired surface slope measurement accuracy of the instrument is <50 nrad (absolute) that is adequate to the current and foreseeable future needs for metrology of x-ray optics for the next generation of light sources.

  15. Adaptive slope compensation for high bandwidth digital current mode controller

    DEFF Research Database (Denmark)

    Taeed, Fazel; Nymand, Morten

    An adaptive slope compensation method for digital current mode control of dc-dc converters is proposed in this paper. The compensation slope is used for stabilizing the inner current loop in peak current mode control. In this method, the compensation slope is adapted with the variations in...... converter duty cycle. The adaptive slope compensation provides optimum controller operation in term of bandwidth over wide range of operating points. In this paper operation principle of the controller is discussed. The proposed controller is implemented in an FPGA to control a 100 W buck converter. The...... experimental results of measured loop-gain at different operating points are presented to validate the theoretical performance of the controller....

  16. Impact Analysis of Blasting Vibration on the Slope and Dump

    Directory of Open Access Journals (Sweden)

    Zhang De

    2014-01-01

    Full Text Available As known that the blasting on the slope is very dangerous in the exploration of the mine andneeds complex analysis and calculation on the slope and dump. In the study it adopts the regression method in the analysis of important parameters of the vibration experiments of iron ore stope which influence the stability of slope and vibration velocity of mine blasting, vibration acceleration, etc., it makes the analysis of power spectrum and dynamic response. Through the model of landslide dynamic response it analyzes the rule of blasting vibration and the blasting vibration influence on the stability of slope, the research can provide a safety criterion in the exploitation of the iron ore.

  17. Interpretation of Schubert plot slopes for metal-humate systems

    International Nuclear Information System (INIS)

    In this paper an error in the literature is identified pertaining to the interpretation of nonintegral slopes in Schubert plots for metal-humate and metal-fulvate systems. Equations are derived that correctly describe the behavior of these systems

  18. Newton slopes for Artin-Schreier-Witt towers

    DEFF Research Database (Denmark)

    Davis, Christopher James; Wan, Daqing

    2015-01-01

    We fix a monic polynomial f(x) in Fq[x] over a finite field and consider the Artin-Schreier-Witt tower defined by f (x); this is a tower of curves · · · ? Cm ? Cm?1 ? ···?C0 =A1, with total Galois group Zp. We study the Newton slopes of zeta functions of this tower of curves. This reduces to the study of the Newton slopes of L-functions associated to characters of the Galois group of this tower. We prove that, when the conductor of the character is large enough, the Newton slopes of the L-function form arithmetic progressions which are independent of the conductor of the character. As a corollary, we obtain a result on the behavior of the slopes of the eigencurve associated to the Artin-Schreier-Witt tower, analogous to the result of Buzzard and Kilford.

  19. Slope stability of geosynthetic clay liner test plots

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, D.E. [Univ. of Illinois, Urbana, IL (United States); Koerner, R.M. [Drexel Univ., Philadelphia, PA (United States). Geosynthetic Research Inst.; Bonaparte, R. [GeoSyntec Consultants, Atlanta, GA (United States); Landreth, R.E. [Landreth, (Robert E.), West Chester, OH (United States); Carson, D.A. [Environmental Protection Agency, Cincinnati, OH (United States); Scranton, H.B. [Haley and Aldrich, Boston, MA (United States)

    1998-07-01

    Fourteen full-scale field test plots containing five types of geosynthetic clay liners (GCLs) were constructed on 2H:1V and 3H:1V slopes for the purpose of assessing slope stability. The test plots were designed to simulate typical final cover systems for landfills. Slides occurred in two of the 2H:1V test plots along interfaces between textured geomembranes and the woven geotextile components of internally reinforced GCLs. One additional slide occurred within the unreinforced GCL component of a 2H:1V test plot, when the GCL unexpectedly became hydrated. All 3H:1V slopes have remained stable. Results of laboratory direct shear tests compared favorably with field observations, providing support for the current design procedures that engineers are using for assessing the stability of slopes containing GCLs.

  20. North Slope, Alaska ESI: M_MAMMAL (Marine Mammal Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for whales, seals, walruses, and polar bears for the North Slope of Alaska. Vector polygons in this data...

  1. Open pit slope deformation monitoring by fiber Bragg grating sensors

    Science.gov (United States)

    Xu, Guoquan; Xiong, Daiyu; Duan, Yun; Cao, Xiaoshuang

    2015-01-01

    With microstrain resolution and the capability to sample at rates of 2000 Hz or higher, fiber Bragg grating (FBG) strain sensor offers exciting new possibilities for in situ deformation monitoring induced by blasting load in an open pit slope. Here, we are developing a new technology for measuring deformation in real time on the microstrain in an open pit slope during the blasting. A fiber optically instrumented rock mass strain sensor measured strain at 100-cm intervals along a two anchor rock bolt grouted in the slope intact rock mass. In field testing, a number of transient signals have been observed, which in some cases were large enough to trigger rapid sampling. The combination of short- and long-term observation offers new insight into the slope stability and blasting cumulative effects. Therefore, FBG sensors are a useful tool for measuring in situ strain in intact rock masses.

  2. The stability of grounding lines on retrograde slopes

    Directory of Open Access Journals (Sweden)

    G. H. Gudmundsson

    2012-07-01

    Full Text Available The stability of marine ice sheets grounded on beds that slope upwards in the overall direction of flow is investigated numerically in two horizontal dimensions. We give examples of stable grounding lines on such retrograde slopes illustrating that marine ice sheets are not unconditionally unstable in two-horizontal dimensions. Retrograde bed slopes at the grounding lines of maritime ice sheets, such as the West Antarctic Ice Sheet (WAIS, do not per se imply an instability, nor do they imply that these regions are close to a threshold of instability. We therefore question those estimates of the potential near-future contribution of WAIS to global sea level change based solely on the notion that WAIS, resting on retrograde slope, must be inherently unstable.

  3. Application of distinct element method to toppling failure of slopes

    International Nuclear Information System (INIS)

    Recently, the stability of slopes during earthquakes has become to be an important engineering problem, especially in case of the earthquake-proof design of nuclear power plants. But, for fissured rock slopes, some problems are remained unresolved, because they can not be treated as continua. The authors have been investigating toppling failure of slopes, from a point of view which regards a fissured rock mass as an assemblage of rigid blocks. DEM (Distinct Element Method) proposed by Cundall (1974) seems to be very helpful to such a investigation. So, in this paper, the applicability of DEM to toppling failure of slopes is examined through the comparison between DEM results and theoretical or experimental results using 3 simple models. (author)

  4. North Slope, Alaska ESI: T_MAMMAL (Terrestrial Mammal Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for brown bears, caribou, and muskoxen for the North Slope, Alaska. Vector polygons in this data set...

  5. Percent Agricultural Land Cover on Steep Slopes (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Clearing land for agriculture tends to increase soil erosion. The amount of erosion is related to the steepness of the slope, farming methods used and soil type....

  6. Goose banding, Koyukuk and north slope Alaska, 1978

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Goose drive trapping and banding was successfully conducted in the Galena and North Slope areas of Alaska in 1978. This was the fourth year of a five consecutive...

  7. The swans and geese of Alaska's arctic slope

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A midsummer aerial search was made on the 23,000 square miles of waterfowl habitat on Alaskas Arctic slope. Observations included 159 whistling swan Olor...

  8. Submarine landslides along the eastern Mediterranean Israeli continental slope

    Science.gov (United States)

    Reuven, Einav; Katz, Oded; Aharonov, Einat

    2013-04-01

    Numerous shallow submarine slope failures (scars and deposits) are observed in recent high resolution bathymetric grids of the continental slope off the Israeli eastern Mediterranean coast. The nature of these slope failures is currently not comprehensively understood as well as the question of whether the eastern Mediterranean continental slope is continuously or episodically unstable. We report here first steps towards understanding the present state of this submarine landslide system, which include mapping and analyzing the geology of the landslides and the hosting slopes. The continental slope extends from water depths of about 150 to more than 1000 meters with a slope of less than 5 degrees in general. Bathymetric grids with pixel resolution of 15 m till water depth of 700 m and 50 m till water depth of 1700 m were used. Analyzing the bathymetry revealed three main submarine surface features: (a) numerous shallow landslides, within the upper sequence of the post-Messenian sediments. Landslide widths range between hundreds to thousand of meters at the scar, with scar heights up to hundred meters. The toes of the landslides are not always mapable and lay up to a few kilometers down slope from the scar. Slope angles within the scars are 5 to more than15 degrees. At least two types of landslides were detected: presumably young slides with sharp scars, and presumably old slides with secondary slides and secondary drainage systems developed within the scar area; (b) a few kilometers long, north striking step-like lineaments. Step heights are up to 100 meters and the slopes are up to 20 degrees. The offset between parallel steps is less than a kilometer to a few kilometers. The steps are interpreted as surface expressions of growth faults rooted at the Messinian evaporates up to 1.5 kilometers below surface; (c) a few north striking channels were also detected with steep walls of more than 15 degrees, up to two kilometers width and a few kilometers length. The nature of these channels is not clear yet. Field relations show that the landslides, both young and old, either emerge from the over-steepened steps, or are displaced by them, and hence submarine landslides and steps are apparently contemporaneous. In addition this suggests that salt dynamics at depth is a main drive for at least some of these shallow slides. The above preliminary results testify to the complicated and highly dynamic nature of the studied continental slope, yet to be revealed.

  9. On the Slope and Geography of Fibred Surfaces and Threefolds.

    OpenAIRE

    Barja Yáñez, Miguel Ángel

    1998-01-01

    [eng] In this tesis we study numerical propieties of surfaces and threefolds, mainly fibred over curves, the so called "slope" of the fibration. We prove partially a conjecture of Fujita on the semiampleness of the direct image of the relative dualizing sheaf of a fibration. We give new lower bounds of the slope of a fibred surface depending on data of the general fibre (existence of involutions) and on data of the hole surface (the fibration not being the Albanese morphism, for example)....

  10. Simulating the seismic behaviour of soil slopes and embankments

    DEFF Research Database (Denmark)

    Zania, Varvara; Tsompanakis, Yiannis; Psarropoulos, Prodromos

    2010-01-01

    In the current study the clarification of the main assumptions, related to the two most commonly used methods of seismic slope stability analysis (pseudostatic and permanent deformation) is attempted. The seismic permanent displacements and the corresponding seismic coefficients were determined via parametric dynamic numerical analyses taking into account not only the main parameters dominating the seismic slope stability, but also the inherent assumptions of the applied approaches that affect t...

  11. Hybrid Method for Analysis and Design of Slope Stabilizing Piles

    OpenAIRE

    Kourkoulis, Rallis; Gelagoti, Fani; Anastasopoulos, Ioannis; GAZETAS, George

    2011-01-01

    iles are extensively used as a means of slope stabilization. Despite the rapid advances in computing and software power, the design of such piles may still include a high degree of conservatism stemming from the use of simplified easy to apply methodologies. This paper develops a hybrid method for designing slope stabilizing piles, combining the accuracy of rigorous 3D finite element (FE) simulation with the simplicity of widely accepted analytical techniques. It comprises two steps : (a) eva...

  12. Exploring Benthic Biodiversity Patterns and Hotspots on European Margin Slopes

    OpenAIRE

    Roberto Danovaro; Miquel Canals; Serge Heussner; Nikolaos Lampadariou; Ann Vanreusel

    2009-01-01

    There is increasing evidence that continental slope ecosystems represent one of the major repositories of benthic marine biodiversity. The enhanced levels of biodiversity along slopes are hypothesized to be a source of biodiversity for continental shelves and deeper basins. Continental margins are increasingly altered by human activities, but the consequences of these anthropogenic impacts on benthic biodiversity and ecosystem functioning are almost completely unknown. Thus, there is an urgen...

  13. Analysis of slope stabilization by soil bioengineering method

    Science.gov (United States)

    Switala, Barbara Maria; Wu, Wei

    2013-04-01

    The aim of the project is to create a numerical model which will include the impact of vegetation on the slope stability analysis, considering both mechanical and hydrological factors. This will enrich the current knowledge about how roots reinforce the soil layers on the slope and how it influences the increase of shear strength of the soil. This has to be combined together with hydrological effects caused by evapotranspiration: modified soil moisture regime, dissipation of excess pore pressure and established matric suction. Coupled analyses (mechanical and hydrological) are rarely conducted, or only outdated models are used, which leads to overestimation of the additional shear strength of soil. That is why there is a need to support this branch of landslide hazard assessment and develop a new model. This research will help to raise awareness, that soil bioengineering methods of slope stabilization can in some cases be more appropriate and less expensive than traditional methods. As an input to the model, the appropriate slope geometry and soil properties have to be chosen. It is also important to consider different plant types and root properties, as well as different levels of groundwater table. To assess the effect of evapotranspiration it is necessary to know the geographical location of the slope and the weather conditions in the chosen region. The final output of the model, which will help to quantitatively assess the impact of vegetation on the slope stability, is the factor of safety (FOS) for vegetated slope for different types of soil and degrees of saturation. Results may then be compared with different conditions and factors of safety, calculated for the corresponding non-vegetated slope. It will be possible to specify the most favorable and unfavorable conditions. Moreover, the calculations provide also information on changes of cohesion, caused by mechanical and hydrological effects, as well as the change in the friction angle of soil.

  14. The effect of a single point on correlation and slope

    OpenAIRE

    David L. Farnsworth

    1990-01-01

    By augmenting a bivariate data set with one point, the correlation coefficient and/or the slope of the regression line can be changed to any prescribed values. For the target value of the correlation coefficient or the slope, the coordinates of the new point are found as a function of certain statistics of the original data. The location of this new point with respect to the original data is investigated.

  15. Geospatial Data Integration for Assessing Landslide Hazard on Engineered Slopes

    Science.gov (United States)

    Miller, P. E.; Mills, J. P.; Barr, S. L.; Birkinshaw, S. J.

    2012-07-01

    Road and rail networks are essential components of national infrastructures, underpinning the economy, and facilitating the mobility of goods and the human workforce. Earthwork slopes such as cuttings and embankments are primary components, and their reliability is of fundamental importance. However, instability and failure can occur, through processes such as landslides. Monitoring the condition of earthworks is a costly and continuous process for network operators, and currently, geospatial data is largely underutilised. The research presented here addresses this by combining airborne laser scanning and multispectral aerial imagery to develop a methodology for assessing landslide hazard. This is based on the extraction of key slope stability variables from the remotely sensed data. The methodology is implemented through numerical modelling, which is parameterised with the slope stability information, simulated climate conditions, and geotechnical properties. This allows determination of slope stability (expressed through the factor of safety) for a range of simulated scenarios. Regression analysis is then performed in order to develop a functional model relating slope stability to the input variables. The remotely sensed raster datasets are robustly re-sampled to two-dimensional cross-sections to facilitate meaningful interpretation of slope behaviour and mapping of landslide hazard. Results are stored in a geodatabase for spatial analysis within a GIS environment. For a test site located in England, UK, results have shown the utility of the approach in deriving practical hazard assessment information. Outcomes were compared to the network operator's hazard grading data, and show general agreement. The utility of the slope information was also assessed with respect to auto-population of slope geometry, and found to deliver significant improvements over the network operator's existing field-based approaches.

  16. A new vision of carbonate slopes: the Little Bahama Bank

    Science.gov (United States)

    Mulder, Thierry; Gillet, Hervé; Hanquiez, Vincent; Reijmer, John J.; Tournadour, Elsa; Chabaud, Ludivine; Principaud, Mélanie; Schnyder, Jara; Borgomano, Jean

    2015-04-01

    Recent data collected in November 2014 (RV Walton Smith) on the upper slope of the Little Bahama Bank (LBB) between 30 and 400 m water depth allowed to characterize the uppermost slope (Rankey et al., 2012) over a surface of 170 km2. The new data set includes multibeam bathymetry and acoustic imagery, 3.5 kHz very-high resolution (VHR) seismic reflection lines, 21 gravity cores and 11 Van Veen grabs. The upper slope of the LBB does not show a steep submarine cliff as known from western Great Bahama Bank. The carbonate bank progressively deepens towards the basin through a slighty inclined plateau. The slope value is Halimeda. Sediments collected in the deeper part of the basin (water depth = 1080 m) on the distal lobe consist of massive fine to medium well-sorted aragonitic sand. This suggests that carbonate slope systems are able to sort sediment despite the relative short slope distance. Sorting could either be due to flow spilling above the terraces identified in the canyon heads (Mulder et al., 2012) or could result from bottom currents. In this area, flow velocity profiles in the water column show the presence of two superposed water masses with a pycnocline at about 600-700 m water depth. Mulder, T., Ducassou, E., Gillet, H., Hanquiez, V., Tournadour, E., Combes, J., Eberli, G.P, Kindler, P., Gonthier, E., Conesa, G., Robin, C., Sianipar, R., Reijmer, J.J.G., and François A. Canyon morphology on a modern carbonate slope of the Bahamas: Evidence of regional tectonic tilting. Geology, 40(9), 771-774. Rankey, E.C, and Doolittle, D.F. (2012). Geomorphology of carbonate platform-marginal uppermost slopes: Insights from a Holocene analogue, Little Bahama Bank, Bahamas. Sedimentology, 59, 2146-2171.

  17. Assessment of cropland area on sloping land in DPRK

    Science.gov (United States)

    Kerdiles, H.; Spyratos, S.; Gallego, F. J.

    2014-03-01

    Following the famines of the mid 1990s, the government of the Democratic People's Republic of Korea (DPRK) authorized cultivation on sloping land before deciding, in the years 2000, to limit this practice on slopes above 15 degrees in order to reduce erosion. There are still many cultivated fields on slopes and their total estimated area ranges from 300,000 ha to more than 2 million ha. This study aims at assessing cropland areas on slopes above 10 and 15 degrees by using high to very high resolution remote sensing satellite imagery. For this purpose, a grid of points was superimposed over the DPRK territory and stratified according to slope, as derived from two DEMs, the 30 m ASTER GDEM V2 and the 3 arc second (~90 m) SRTM Dem V4. A sample of about 2100 points was drawn using an optimal allocation sampling plan, based on a preliminary assessment of the variance of the estimated cropland percentage per class of slope. These 2100 points were interpreted into cropland, no cropland and doubt using mostly Google Earth imagery acquired after 2004. For slopes above 10 degrees, the area cropped was estimated to be around 1,000,000 ha (5.6% CV) and 742,000 ha (8.1% CV) according to the ASTER and SRTM DEM respectively. Above 15 degrees, the estimated cropland area ranges from 360,000 ha (9.7% CV) with SRTM to 540,000 ha (6.6.% CV) with ASTER. To decide between these two estimations, a validation of the two DEMs should be carried out on a region with similar relief. Alternatively, a higher accuracy DEM such as the one to be derived from the TanDEM-X mission in 2014 should provide more accurate estimates of the cropland area on sloping land.

  18. Performance of the APS optical slope measuring system

    International Nuclear Information System (INIS)

    An optical slope measuring system (OSMS) was recently brought into operation at the Advanced Photon Source of the Argonne National Laboratory. This system is equipped with a precision autocollimator and a very accurate mirror-based pentaprism on a scanning stage and kept in an environment-controlled enclosure. This system has the capability to measure precision optics with sub-microradian rms slope errors as documented with a series of tests demonstrating accuracy, stability, reliability and repeatability. Measurements of a flat mirror with 0.2 ?rad rms slope error are presented which show that the variation of the slope profile measurements with the mirror setting at different locations along the scanning direction is only 60 nrad and the corresponding height error profile has 2 nm rms. -- Highlights: ? This is the first time to present the APS OSMS in publication. ? The APS OSMS is capable to measure flat and near flat mirrors with slope error <100 nrad rms. ? The accuracy of the slope error measurements of a 350 mm long mirror is less than 60 nrad rms

  19. Problems of definitive slopes mining at Doly Nastup Tusimice

    International Nuclear Information System (INIS)

    The instability of slopes influents mining business in many aspects at open-cast mining. The temporary decrease of intended mined volumes due to land slips is common and sometimes there is necessary to change origin-mining plans. It has impact to economy and other essential costs for rehabilitation are required. In case of definitive slopes formation in contact to traffic and communication networks, watercourses and infrastructures of seats stability of slope security there is even more important. Monitoring of rock massive stability plays an important role. Everything which stability of slopes is concerned belongs to essential tasks for mining technicians at open-cast mining. The article explains what ways for definitive slope formation near mining boundary were selected at Severoceske doly j.s.c., Doly Nastup Tusimice mining site. The precautions refer to mining technology, preventive and reconstruction precautions for stabilization of slopes must to solve, are to described. Tasks, which mining engineers, surveyors, geologists and geotechnics have to solve are described. (authors)

  20. Exploring Benthic Biodiversity Patterns and Hotspots on European Margin Slopes

    Directory of Open Access Journals (Sweden)

    Roberto Danovaro

    2009-03-01

    Full Text Available There is increasing evidence that continental slope ecosystems represent one of the major repositories of benthic marine biodiversity. The enhanced levels of biodiversity along slopes are hypothesized to be a source of biodiversity for continental shelves and deeper basins. Continental margins are increasingly altered by human activities, but the consequences of these anthropogenic impacts on benthic biodiversity and ecosystem functioning are almost completely unknown. Thus, there is an urgent need to gather sufficient information to enable us to understand patterns and drivers of deep-sea biodiversity along continental margins. Although the local diversity of some deep open slope ecosystems is moderately well documented, very little is known about the biodiversity of these systems at greater spatial scales. Topographic setting, hydrodynamic forcing, and the biogeochemical characteristics of the deep-sea floor may play key roles in promoting and sustaining high biodiversity along the open slopes of continental margins. HERMES provided the opportunity to acquire a significant volume of information on the biodiversity, trophic conditions, and topographic characteristics of open slopes across European margins, increasing our knowledge of the latitudinal, longitudinal, and bathymetric patterns of benthic biodiversity, and extending our comprehension of the mechanisms driving deep-sea biodiversity and its potential loss. Improved knowledge of these processes is needed to inform policy decisions for promoting sustainable management of open slopes and deep-sea ecosystems along continental margins.

  1. Katabatic Flow Mechanisms on a Low-Angle Slope

    Energy Technology Data Exchange (ETDEWEB)

    Haiden, Thomas S.; Whiteman, Charles D.

    2005-01-01

    Momentum and heat budget equations are written for katabatic flows on sloping surfaces. Terms in these equations are evaluated using wind and potential temperature data from four tethered balloon data collection systems on a 3-km line running down a 1.6° slope at the foot of the Oquirrh Mountains in Utah’s Salt Lake Valley. The analyses focus on the development with downslope distance of the katabatic flow and the associated negatively buoyant layer. Under conditions of strong stratification, the katabatic flow shows little variation between sites, suggesting a state close to local equilibrium. With weaker ambient stratification, the acceleration of the katabatic flow between two tethersonde sites is systematically larger than what would be predicted based on observed buoyancy. Comparison of observed flow direction with the local topographic gradient indicates that slope curvature, associated with small deviations from the basically planar slope, may be responsible for the anomalous increase. It is concluded that the assumption of cross-slope homogeneity of the flow which is assumed in simplified katabatic flow models is not even found on slopes which appear planar to the visual observer.

  2. Relating weak layer and slab properties to snow slope stability

    Directory of Open Access Journals (Sweden)

    J. Schweizer

    2014-07-01

    Full Text Available Snow slope stability evaluation requires considering weak layer as well as slab properties – and in particular their interaction. We developed a stability index from snow micro-penetrometer measurements and compared it to 129 concurrent point observations with the compression test (CT. The index considers the SMP-derived micro-structural strength and the additional load which depends on the hardness of the surface layers. The new quantitative measure of stability discriminated well between point observations rated as either "poor" or "fair" (CT < 19 and those rated as "good" (CT ? 19. However, discrimination power within the intermediate range was low. We then applied the index to gridded snow micro-penetrometer measurements from 11 snow slopes to explore the spatial structure and possibly relate it to slope stability. Stability distributions on the 11 slopes reflected various possible strength and load (stress distributions that naturally can occur. Their relation to slope stability was poor possibly because the index does not consider crack propagation. Hence, the relation between spatial patterns of point stability and slope stability remains elusive. Whereas this is the first attempt of a truly quantitative measure of stability, future developments should consider a better reference of stability and incorporate a measure of crack propagation.

  3. Soil properties in high-elevation ski slopes

    Science.gov (United States)

    Filippa, Gianluca; Freppaz, Michele; Letey, Stéphanie; Corti, Giuseppe; Cocco, Stefania; Zanini, Ermanno

    2010-05-01

    The development of winter sports determines an increasing impact on the high altitude ecosystems, as a consequence of increased participation and an increasing demand of high quality standards for skiable areas. The construction of a ski slope is associated with a certain impact on soil, which varies as a function of the degree of human-induced disturbance to the native substrata. In this work, we provide a description of the characteristics of alpine tundra ski-slope soils and their nutrient status, contrasted with undisturbed areas. The study site is located in the Monterosaski Resort, Aosta Valley, NW Italy (45°51' N; 7°48' E). We chose 5 sites along an altitudinal gradient between 2700 and 2200 m a.s.l.. Per each site, one plot was established on the ski slope, while a control plot was chosen under comparable topographic conditions a few meters apart. Soils were described and samples were collected and analysed for main chemical-physical properties. In addition an evaluation of N forms, organic matter fractionation and microbial biomass was carried out. Soil depth ranged between 10 to more than 70 cm, both on the ski slope and in the undisturbed areas. A true organo-mineral (A) horizon was firstly identified at 2500 m a.s.l., while a weathering horizon (Bw) was detected at 2400 m a.s.l.. However, a Bw horizon thick enough to be recognised as diagnostic for shifting soil classification order from Entisols to Inceptisols (USDA-Soil Taxonomy) was detected only below 2400 m a.s.l.. Lithic Cryorthents were predominant in the upper part of the sequence (above 2500 m a.s.l.), both in the ski slope and the undisturbed areas; Typic Cryorthents were identified between 2500 and 2400 m a.s.l., while Inceptisols were predominant between 2400 and 2200 m a.s.l.. Chemical-physical properties will be discussed focusing on the main differences between ski slope and undisturbed soils, as determined by the ski slope construction. Pedogenetic processes at high altitude are strongly limited by extreme climatic conditions, resulting in low resistance and resilience with respect to any human-induced changes; therefore, it is key to quantify the impact of ski slope construction and management on such fragile pedo-ecosystems. KEYWORDS: alpine tundra, pedogenesis, ski slope construction, ski slope management

  4. Quantifying Slopes with Digital Elevation Models of the Verdugo Hills, California: Effects of Resolution

    Science.gov (United States)

    Fielding, E. J.; Burbank, D. W.; Duncan, C. C.

    1996-01-01

    Quantification of surface slope angles is valuable in a wide variety of earth sciences. Slopes measured from digital elevation models (DEMs) or other topographic data sets depend strongly on the length scale or window size used in the slope calculations.

  5. Slope Derivative Surface used to characterize the complexity of the seafloor around St. John, USVI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Slope was calculated from the bathymetry surface for each raster cell using ArcGIS's Spatial Analyst 'Slope' Tool. Slope describes the maximum steepness of a...

  6. Comprehensive evaluation of high-steep slope stability and optimal high-steep slope design by 3D physical modeling

    Science.gov (United States)

    Lai, Xing-ping; Shan, Peng-fei; Cai, Mei-feng; Ren, Fen-hua; Tan, Wen-hui

    2015-01-01

    High-steep slope stability and its optimal excavation design in Shuichang open pit iron mine were analyzed based on a large 3D physical simulation technique. An optimal excavation scheme with a relatively steeper slope angle was successfully implemented at the northwest wall between Nos. 4 and 5 exploration lines of Shuichang Iron Mine, taking into account the 3D scale effect. The physico-mechanical properties of rock materials were obtained by laboratory tests conducted on sample cores from exploration drilling directly from the iron mine. A porous rock-like composite material was formed for the model, and the mechanical parameters of the material were assessed experimentally; specifically, the effect of water on the sample was quantitatively determined. We adopted an experimental setup using stiff modular applied static loading to carry out a visual excavation of the slope at a random depth. The setup was equipped with acoustic emission (AE) sensors, and the experiments were monitored by crack optical acquirement, ground penetrating radar, and close-field photogrammetry to investigate the mechanisms of rock-mass destabilization in the high-steep slope. For the complex study area, the model results indicated a clear correlation between the model's destabilization resulting from slope excavation and the collected monitoring information. During the model simulation, the overall angle of the slope increased by 1-6 degrees in different sections. Dramatically, the modeled excavation scheme saved over 80 million tons of rock from extraction, generating enormous economic and ecological benefits.

  7. Simulation of a sloped solar chimney power plant in Lanzhou

    International Nuclear Information System (INIS)

    Research highlights: ? A sloped solar chimney power plant in Lanzhou, China is investigated. ? The configuration sizes are designed separately. ? The system has high periodicity and stability but low efficiency. ? The sloped solar chimney power system is of high value for Northwest China. -- Abstract: Solar chimney power system is one large-scale utilization style of solar energy, which has drawn high attentions worldwide. Though scholars all over the world have made many researches on the solar chimney power system, reports of sloped solar chimney power system are still few. A sloped solar chimney power plant, which is expected to provide electric power for remote villages in Northwest China, has been designed for Lanzhou City in this paper. The designed plant, in which the height and radius of the chimney are 252.2 m and 14 m respectively, the radius and angle of the solar collector are 607.2 m and 31o respectively, is designed to produce 5 MW electric power on a monthly average all year. The performances, such as the airflow temperature increase, pressure, the airflow speed, system efficiency and solar collector efficiency, of the built sloped solar chimney power plant are simulated and presented. Simulation results show that parameters of the sloped solar chimney power plant are symmetrical and stable; the power plant has better performances in spring and autumn days; the overall efficiency of the power plant is low. Considering the abundant solar radiation, environmental friendliness, easy management and low population density, the sloped solar chimney power system is of high value to Northwest China.

  8. Slope stability along active and passive continental margins: a geotechnical approach

    OpenAIRE

    Ai, Fei

    2013-01-01

    Submarine mass movements are widespread at submarine slopes and play an important role in transporting sediments across the continental slope to the deep basin, as well as potential danger to both offshore infrastructures (e.g., pipeline, cables and platforms) and coastal areas (e.g., slope failure-induced tsunamis). Sliding of the sediments on continental slope takes place when the shear stress within sediments exceeds the shear strength thereby causing slope failure. Slope failures are gene...

  9. Research on the Slope Green and Environment Protection Using Dynamical Game Theory

    OpenAIRE

    Juan Wan; Henglin Xiao; Jun He; Lihua Li

    2013-01-01

    This study aims to investigate the slope green and environment protection in China. In ecological slope protection, the plant roots can achieve the ecological vegetation restoration of the slope surface. Hence the slope environment can be protected significantly. However, there is still lack of efficient policy to support the implementation of nationwide slope green program to facilitate the development of slope green and environment protection technologies. Hence, the reasonable relationship...

  10. Application of Grey Theory and Wavelet Neural Network in Slope Displacements Prediction

    OpenAIRE

    Jiang Ping

    2013-01-01

    Slope displacement is the external performance of slope stability, predicting slope displacement according to the original displacement monitoring data and predicting slope stability, which can effectively prevent the occurrence of landslide disaster. Slope displacement can be regard as the sum of trend item and random item, grey system G (1, 1) model can simulate the trend of the slope displacement time series and the wavelet neural network can predict the ...

  11. Direct Strain and Slope and Slope Measurement Using 2D DSPSI

    International Nuclear Information System (INIS)

    Large variety of optical full-field measurement techniques are being developed and applied to solve mechanical problems. Since each technique possesses its own merits, it is important to know the capabilities and limitations of such techniques. Among these optical full-field methods, interferometry techniques take an important place. They are based on illumination with coherent light (laser). In shearing interferometry the difference of the out of-plane displacement in two neighboring object points is directly measured. Since object displacement does not result in interferometry fringes, the method is suited for localization of strain concentrations and is indeed used in industry for this purpose. DSPSI possesses the advantage over conventional out-of-plane displacement-sensitive interferometry, that only a single difference of the unwrapped phase map is required to obtain flexural strains, thereby relieving problems with noise and reduction in the field of view. A first work in this domain (DSPSI) [1] was made in 1973, later recent studies emerged to provide a quantitative system of measurements [2]. This work aims to present the results of strain and slope measurements using digital speckle pattern shearing interferometry (DSPSI). (author)

  12. Slope Error Measurement Tool for Solar Parabolic Trough Collectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Stynes, J. K.; Ihas, B.

    2012-04-01

    The National Renewable Energy Laboratory (NREL) has developed an optical measurement tool for parabolic solar collectors that measures the combined errors due to absorber misalignment and reflector slope error. The combined absorber alignment and reflector slope errors are measured using a digital camera to photograph the reflected image of the absorber in the collector. Previous work using the image of the reflection of the absorber finds the reflector slope errors from the reflection of the absorber and an independent measurement of the absorber location. The accuracy of the reflector slope error measurement is thus dependent on the accuracy of the absorber location measurement. By measuring the combined reflector-absorber errors, the uncertainty in the absorber location measurement is eliminated. The related performance merit, the intercept factor, depends on the combined effects of the absorber alignment and reflector slope errors. Measuring the combined effect provides a simpler measurement and a more accurate input to the intercept factor estimate. The minimal equipment and setup required for this measurement technique make it ideal for field measurements.

  13. Characterization of Unstable Rock Slopes Through Passive Seismic Measurements

    Science.gov (United States)

    Kleinbrod, U.; Burjanek, J.; Fäh, D.

    2014-12-01

    Catastrophic rock slope failures have high social impact, causing significant damage to infrastructure and many casualties throughout the world each year. Both detection and characterization of rock instabilities are therefore of key importance. An analysis of ambient vibrations of unstable rock slopes might be a new alternative to the already existing methods, e.g. geotechnical displacement measurements. Systematic measurements have been performed recently in Switzerland to study the seismic response of potential rockslides concerning a broad class of slope failure mechanisms and material conditions. Small aperture seismic arrays were deployed at sites of interest for a short period of time (several hours) in order to record ambient vibrations. Each measurement setup included a reference station, which was installed on a stable part close to the instability. Recorded ground motion is highly directional in the unstable parts of the rock slope, and significantly amplified with respect to stable areas. These effects are strongest at certain frequencies, which were identified as eigenfrequencies of the unstable rock mass. In most cases the directions of maximum amplification are perpendicular to open cracks and in good agreement with the deformation directions obtained by geodetic measurements. Such unique signatures might improve our understanding of slope structure and stability. Thus we link observed vibration characteristics with available results of detailed geological characterization. This is supported by numerical modeling of seismic wave propagation in fractured media with complex topography.For example, a potential relation between eigenfrequencies and unstable rock mass volume is investigated.

  14. Retrieval of short ocean wave slope using polarimetric imaging

    International Nuclear Information System (INIS)

    We present a passive optical remote sensing technique for recovering shape information about a water surface, in the form of a two-dimensional slope map. The method, known as polarimetric slope sensing (PSS), uses the relationship between surface orientation and the change in polarization of reflected light to infer the instantaneous two-dimensional slope across the field-of-view of an imaging polarimeter. For unpolarized skylight, the polarization orientation and degree of linear polarization of the reflected skylight provide sufficient information to determine the local surface slope vectors. A controlled laboratory experiment was carried out in a wave tank with mechanically generated gravity waves. A second study was performed from a pier on the Hudson River, near Lamont-Doherty Earth Observatory. We demonstrated that the two-dimensional slope field of short gravity waves could be recovered accurately without interfering with the fluid dynamics of the air or water, and water surface features appear remarkably realistic. The combined field and laboratory results demonstrate that the polarimetric camera gives a robust characterization of the fine-scale surface wave features that are intrinsic to wind-driven air–sea interaction processes

  15. Infinite slope stability under steady unsaturated seepage conditions

    Science.gov (United States)

    Lu, N.; Godt, J.

    2008-01-01

    [1] We present a generalized framework for the stability of infinite slopes under steady unsaturated seepage conditions. The analytical framework allows the water table to be located at any depth below the ground surface and variation of soil suction and moisture content above the water table under steady infiltration conditions. The framework also explicitly considers the effect of weathering and porosity increase near the ground surface on changes in the friction angle of the soil. The factor of safety is conceptualized as a function of the depth within the vadose zone and can be reduced to the classical analytical solution for subaerial infinite slopes in the saturated zone. Slope stability analyses with hypothetical sandy and silty soils are conducted to illustrate the effectiveness of the framework. These analyses indicate that for hillslopes of both sandy and silty soils, failure can occur above the water table under steady infiltration conditions, which is consistent with some field observations that cannot be predicted by the classical infinite slope theory. A case study of shallow slope failures of sandy colluvium on steep coastal hillslopes near Seattle, Washington, is presented to examine the predictive utility of the proposed framework. Copyright 2008 by the American Geophysical Union.

  16. A preliminary pit slope stability study Kvanefjeld, South Greenland

    International Nuclear Information System (INIS)

    On the basis of 1300 field measurements of joint planes, four individual structural regions have been outlined in the Kvanefjeld area. Potential failure planes and planes which are unlikely to be involved in slope failures are identified. Failures seem, not likely to occur on walls dipping SW or NE respectively, but may occur on walls dipping NM. The factors of safety for each region are calculated in order to determine the sensibility of the overall slope to different overall slope angles. The factors of safety does only exceed the required factor of safety of 1.5 in one of the structural regions. Changing the overall pit slope inclination from 55deg to 45deg improves the security, but even still not satisfactorily for two of the regions. At 45deg overall pit slope in parts of the pit implies additional 14.3 x 106 tonnes of non-mineralized material to be mined, thus resulting in a total mineralized- to non-mineralized material ratio about 1.0: 1.7. (author)

  17. After the slippery slope: Dutch experiences on regulating active euthanasia.

    Science.gov (United States)

    Boer, Theo A

    2003-01-01

    "When a country legalizes active euthanasia, it puts itself on a slippery slope from where it may well go further downward." If true, this is a forceful argument in the battle of those who try to prevent euthanasia from becoming legal. The force of any slippery slope argument, however, is by definition limited by its reference to future developments which cannot empirically be sustained. Experience in the Netherlands--where a law regulating active euthanasia was accepted in April 2001--may shed light on the strengths as well as the weaknesses of the slippery slope argument in the context of the euthanasia debate. This paper consists of three parts. First, it clarifies the Dutch legislation on euthanasia and explains the cultural context in which it originated. Second, it looks at the argument of the slippery slope. A logical and an empirical version are distinguished, and the latter, though philosophically less interesting, proves to be most relevant in the discussion on euthanasia. Thirdly, it addresses the question whether Dutch experiences in the process of legalizing euthanasia justify the fear of the slippery slope. The conclusion is that Dutch experiences justify some caution. PMID:16175719

  18. Reliability-based Assessment of Stability of Slopes

    Science.gov (United States)

    Hsein Juang, C.; Zhang, J.; Gong, W.

    2015-09-01

    Multiple sources of uncertainties often exist in the evaluation of slope stability. When assessing stability of slopes in the face of uncertainties, it is desirable, and sometimes necessary, to adopt reliability-based approaches that consider these uncertainties explicitly. This paper focuses on the practical procedures developed recently for the reliability-based assessment of slope stability. The statistical characterization of model uncertainty and parameter uncertainty are first described, followed by an evaluation of the failure probability of a slope corresponding to a single slip surface, and the system failure probability. The availability of site-specific information then makes it possible to update the reliability of the slope through the Bayes’ theorem. Furthermore, how to perform reliability-based design when the statistics of random variables cannot be determined accurately is also discussed. Finally, case studies are presented to illustrate the benefit of performing reliability-based design and the procedure for conducting reliability-based robust design when the statistics of the random variables are incomplete.

  19. Robustness for slope stability modelling under deep uncertainty

    Science.gov (United States)

    Almeida, Susana; Holcombe, Liz; Pianosi, Francesca; Wagener, Thorsten

    2015-04-01

    Landslides can have large negative societal and economic impacts, such as loss of life and damage to infrastructure. However, the ability of slope stability assessment to guide management is limited by high levels of uncertainty in model predictions. Many of these uncertainties cannot be easily quantified, such as those linked to climate change and other future socio-economic conditions, restricting the usefulness of traditional decision analysis tools. Deep uncertainty can be managed more effectively by developing robust, but not necessarily optimal, policies that are expected to perform adequately under a wide range of future conditions. Robust strategies are particularly valuable when the consequences of taking a wrong decision are high as is often the case of when managing natural hazard risks such as landslides. In our work a physically based numerical model of hydrologically induced slope instability (the Combined Hydrology and Stability Model - CHASM) is applied together with robust decision making to evaluate the most important uncertainties (storm events, groundwater conditions, surface cover, slope geometry, material strata and geotechnical properties) affecting slope stability. Specifically, impacts of climate change on long-term slope stability are incorporated, accounting for the deep uncertainty in future climate projections. Our findings highlight the potential of robust decision making to aid decision support for landslide hazard reduction and risk management under conditions of deep uncertainty.

  20. Slope-reversed Mott transition in multiorbital systems

    Science.gov (United States)

    Kim, Aaram J.; Choi, MooYoung; Jeon, Gun Sang

    2015-09-01

    We examine finite-temperature phase transitions in the two-orbital Hubbard model with different bandwidths by means of the dynamical mean-field theory combined with the continuous-time quantum Monte Carlo method. It is found that there emerges a peculiar slope-reversed first-order Mott transition between the orbital-selective Mott phase and the Mott insulator phase in the presence of Ising-type Hund's coupling. The origin of the slope-reversed phase transition is clarified by the analysis of the temperature dependence of the energy density. It turns out that the increase of Hund's coupling lowers the critical temperature of the slope-reversed Mott transition. Beyond a certain critical value of Hund's coupling the first-order transition turns into a finite-temperature crossover. We also reveal that the orbital-selective Mott phase exhibits frozen local moments in the wide orbital, which is demonstrated by the spin-spin correlation functions.

  1. Modal wavefront reconstruction from slope measurements for rectangular apertures.

    Science.gov (United States)

    Li, Mengyang; Li, Dahai; Zhang, Chen; E, Kewei; Wang, Qionghua; Chen, Haiping

    2015-11-01

    We present a modal wavefront reconstruction from slope measurements for rectangular optical components of high-power laser systems. Wavefront reconstruction with slope data is an important approach used for wavefront control or correction in high-power systems. In this work, we derive a complete set of orthonormal wavefront slope polynomials for rectangular apertures and describe the modal method for obtaining wavefront representation with the aberration balancing property. Error propagation properties for the modal method are evaluated and compared with the Southwell method. The cross-coupling error is also discussed. Numerical experiments are conducted to illustrate that the modal method can achieve a higher accuracy than the Southwell method. In addition, we also investigate the influence of noise on the modal method compared with that of the Southwell method. PMID:26560904

  2. Violating the General Density-Slope Anisotropy Inequality

    CERN Document Server

    Barber, Jeremy A

    2014-01-01

    We examine the robustness of the well-known empirical relationship between the density slope and the velocity anisotropy of collisionless systems. This relation, known as the Global Density-Slope Anisotropy Inequality (GDSAI) (Ciotti & Morganti, 2010), posits that no collisionless system with a globally positive distribution function exists where the anisotropy exceeds half of the power-law of the density slope. We significantly extend previous indications that the GDSAI is not a universal rule by identifying a class of models where violation occurs. These models possess a globally positive DF, have an isotropic central core, but are not guaranteed to be stable. Our analysis suggests that stability criteria provide a stronger basis for determining if a DF represents an equilibrium solution for a collisionless system.

  3. Slope Stability Analysis Using Radial Slices: A Mathematical Model

    Science.gov (United States)

    Kumar, Gyan Prakash; Das, Adarsha; Rai, Rajesh; Jaiswal, Ashok

    2015-10-01

    In this paper, a mathematical model has been formulated for calculating the factor of safety of a slope. Corresponding computer code has also been developed. Limit equilibrium method (moment equilibrium) has been adopted for calculating the net resulting driving and resisting forces. The probable slip circle region has been divided into radial slices for the simulation process. In this approach, the inter-slice shear forces are zero. Thus, the calculation process becomes simpler as compared to that with vertical slices. The slope stability analyses were done. Validation of the present program was done with existing limit equilibrium based methods. Various models were prepared and analysed with varying geometry and soil strength parameters. These models were also analysed with other limit equilibrium methods like Bishop, Janbu and Spencer method. The results were found to be in agreement with the results of other limit equilibrium methods for the same dump soil properties and slope parameters.

  4. Predicting moisture problems in low-slope roofing

    Energy Technology Data Exchange (ETDEWEB)

    Desjarlais, A.O. [Oak Ridge National Lab., TN (United States); Byars, N.A. [Univ. of North Carolina, Charlotte, NC (United States). Dept. of Engineering Technology

    1998-11-01

    Moisture intrusion is the major reason why low-slope roofing systems fail prematurely. With approximately 75% of all roofing activity being reroofing, the roofing professional is faced with deciding what to do with an existing wet roof on almost a daily basis. This paper describes finite-difference computer modeling that has been performed to address moisture control in low-slope roof systems. Based on a large database of finite difference modeling results, algorithms have been developed that allow the roofing practitioners to simply determine if a roofing system design requires a vapor retarder or if the system can be modified to enhance its tolerance for small leaks. This paper illustrates how modeling results were obtained, describes the process employed to develop the algorithms, and demonstrates how these algorithms can be used to design a moisture tolerant low-slope roof. The range of applicability and limitations of these algorithms is also detailed.

  5. Consequentialism and the slippery slope: a response to Clark.

    Science.gov (United States)

    Hughes, J

    2000-01-01

    Michael Clark has recently argued that the slippery slope argument against voluntary euthanasia is 'entirely consequentialist' and that its use to justify continued prohibition of voluntary euthanasia involves a failure to treat patients who request assistance in ending their lives as ends in themselves. This article argues that in fact the slippery slope is consistent with most forms of deontology, and that it need not involve any violation of the principle that people should be treated as ends, depending upon how that principle is construed. It is concluded that supporters of voluntary euthanasia cannot dismiss the slippery slope argument on the basis of deontological principles but must take seriously the consequences that it postulates and engage in factual argument about their likely extent and about the likely effectiveness of any proposed safeguards. PMID:11789544

  6. VARIABILITY OF ARABLE AND FOREST SOILS PROPERTIES ON ERODED SLOPES

    Directory of Open Access Journals (Sweden)

    Pawe? Wi?niewski

    2014-10-01

    Full Text Available The basic method of reducing soil and land erosion is a change of land use, for example, from arable to forest. Particularly effective as a protective role – according to the Polish law – soil-protecting forests. The thesis presents differences in the deformation of the basic soil properties on moraine slopes, depending on land use. There has been presented the function and the efficiency of the soil-protecting forests in erosion control. The soil cross section transects and soil analysis displayed that soil-protecting forests are making an essential soil cover protection from degradation, inter alia, limiting the decrease of humus content, reduction of upper soil horizons and soil pedons layer. On the afforested slopes it was stated some clear changes of grain size and chemical properties of soils in relation to adjacent slopes agriculturally used.

  7. Newton slopes for Artin-Schreier-Witt towers

    DEFF Research Database (Denmark)

    Davis, Christopher James; Wan, Daqing; Xiao, Liang

    2015-01-01

    We fix a monic polynomial f(x) in Fq[x] over a finite field and consider the Artin-Schreier-Witt tower defined by f (x); this is a tower of curves · · · ? Cm ? Cm?1 ? ···?C0 =A1, with total Galois group Zp. We study the Newton slopes of zeta functions of this tower of curves. This reduces to the...... study of the Newton slopes of L-functions associated to characters of the Galois group of this tower. We prove that, when the conductor of the character is large enough, the Newton slopes of the L-function form arithmetic progressions which are independent of the conductor of the character. As a...

  8. Slope measurement of bent plates using double grating shearing interferometry.

    Science.gov (United States)

    Dhanotia, Jitendra; Prakash, Shashi; Rana, Santosh; Sasaki, Osami

    2011-06-20

    A grating-based shearing interferometeric setup for slope measurement of bent plates has been proposed. The specimen under test is illuminated by a collimated beam from the laser. Light reflected from the specimen passes through two identical holographic gratings placed in tandem. The grating frequency has been so chosen that the diffracted orders from each grating are separated out distinctly. Two first-order beams diffracted from each of the gratings superpose in space. In the resulting interferogram, the fringes due to slope information of the object are visualized. Mathematical formulation for experimental determination of slope values has been undertaken. Validation of the experimental results with theoretical predictions in case of cantilever beam provides good correlation. The main advantage of the technique has been the realization of very compact geometry without the need for spatial filtering arrangement commonly associated with the grating-based techniques used to date. PMID:21691361

  9. Slope measurement of bent plates using double grating shearing interferometry

    International Nuclear Information System (INIS)

    A grating-based shearing interferometeric setup for slope measurement of bent plates has been proposed. The specimen under test is illuminated by a collimated beam from the laser. Light reflected from the specimen passes through two identical holographic gratings placed in tandem. The grating frequency has been so chosen that the diffracted orders from each grating are separated out distinctly. Two first-order beams diffracted from each of the gratings superpose in space. In the resulting interferogram, the fringes due to slope information of the object are visualized. Mathematical formulation for experimental determination of slope values has been undertaken. Validation of the experimental results with theoretical predictions in case of cantilever beam provides good correlation. The main advantage of the technique has been the realization of very compact geometry without the need for spatial filtering arrangement commonly associated with the grating-based techniques used to date.

  10. Monitoring in situ pore pressures for prediction of slope failure on the prodelta slope of the Fraser River delta, Canada

    Science.gov (United States)

    Hill, P. R.; Christian, H. A.

    2003-04-01

    The Fraser River Delta is located in the Georgia Basin, a densely populated marine basin that is subject to significant pressure from multiple uses such as transportation, utilities, coastal infrastructure and fisheries. The submarine part of the delta consists of 5-8 km wide tidal flats and a delta slope with an average slope of 1.5 degrees. Slope stability is an important concern for the safety of port infrastructure and for tsunami risk. Previous work has shown that the slope shows abundant evidence for historic slope failure. New multibeam sonar data is used to re-examine previously-described slope failure features including: (1) an area of frequent liquefaction failure at the active distributary channel mouth; (2) a distributary mouth canyon, submarine channel and debris lobe system; (3) an area of shallow rotational slide blocks or creep ridges; and (4) a large, older slope failure to the south of the main distributary channel. In an effort to better understand the mechanisms of slope failure on the Fraser River delta slope, a program to measure the response of pore fluids to dynamic loading by tides, storm waves and earthquakes has been developed to take advantage of the VENUS submarine cabled observatory to be constructed in the Georgia Basin between 2003 and 2005. The VENUS infrastructure consists of cables that will provide power and two-way, high speed communications, seafloor instrument arrays, a data archive and distribution center and an operations center. Pore pressure time series data can be used to derive the fluid and mechanical properties of the sediment column. The data can also be filtered to remove the tidal signal and the residual variations used to detect the pore pressure response to short time-scale events, such as seismic events. A preliminary data set obtained from a borehole located near the delta front shows a large tidal signal. When tides are removed, the data show a long term, probably seasonal trend in residual pore pressure that may be related to groundwater flow through the delta. Shorter period pore pressure fluctuations may be related to non-tidal water level changes due to wind-forcing. Only small seismic events (M < 4) have occurred since initiation of this time series and no response is visible in the record.

  11. Development of a GIS-based failure investigation system for highway soil slopes

    Science.gov (United States)

    Ramanathan, Raghav; Aydilek, Ahmet H.; Tanyu, Burak F.

    2015-06-01

    A framework for preparation of an early warning system was developed for Maryland, using a GIS database and a collective overlay of maps that highlight highway slopes susceptible to soil slides or slope failures in advance through spatial and statistical analysis. Data for existing soil slope failures was collected from geotechnical reports and field visits. A total of 48 slope failures were recorded and analyzed. Six factors, including event precipitation, geological formation, land cover, slope history, slope angle, and elevation were considered to affect highway soil slope stability. The observed trends indicate that precipitation and poor surface or subsurface drainage conditions are principal factors causing slope failures. 96% of the failed slopes have an open drainage section. A majority of the failed slopes lie in regions with relatively high event precipitation ( P>200 mm). 90% of the existing failures are surficial erosion type failures, and only 1 out of the 42 slope failures is deep rotational type failure. More than half of the analyzed slope failures have occurred in regions having low density land cover. 46% of failures are on slopes with slope angles between 20° and 30°. Influx of more data relating to failed slopes should give rise to more trends, and thus the developed slope management system will aid the state highway engineers in prudential budget allocation and prioritizing different remediation projects based on the literature reviewed on the principles, concepts, techniques, and methodology for slope instability evaluation (Leshchinsky et al., 2015).

  12. Wetting Front Advance From a Point Source in Sloping Fields

    Directory of Open Access Journals (Sweden)

    Behrouz Mostafazadeh

    1998-10-01

    Full Text Available To determine the effects of field slope, emitter discharge, irrigation water volume and soil texture on soil moisture profile and soil surface wetted shape from a point source, field data were collected on three different soil types, three emitter discharges (4, 8, and 12 lph, four slopes (0, 2, 5, and 10%, and five irrigation water volumes (10, 20, 30, 40, and 50 liters with three replications. The results showed that the surface-wetted area increases as the emitter discharge increases. The surface-wetted area decreased with a corresponding increase in emitter discharge in experimental fields with light-textured soils. In experimental fields with heavy textured soils and slopes greater than 5%, the changes in surface-wetted area due to the emitter discharge increases, were higher compared to slopes of less than 5%. Since, a higher emitter discharge would result in higher surface-wetted area, the results showed that for an equal volume of irrigation water, the soil moisture profile was deeper for lower emitter discharge. In general, the volume of wetted zone was higher for greater emitter discharges. It was found that as the volume of irrigation water increased, the volume of wetted zone would increase correspondingly. This effect is more prominent than that of emitter discharge. In general, the depth of wetting front was lower and the wetted surface area was greater for heavy textured soils as compared to the light textured soils. The wetted-surface area and the shape of wetting front in the direction of slope were affected by the soil infiltration, emitter discharge and volume of irrigation water where these effects were more critical in higher sloping lands.

  13. Velocity analysis with local event slopes related probability density function

    Science.gov (United States)

    Zhang, Peng; Lu, Wenkai; Zhang, Yingqiang

    2015-12-01

    Macro velocity model plays a key role in seismic imaging and inversion. The performance of traditional velocity analysis methods is degraded by multiples and amplitude-versus-offset (AVO) anomalies. Local event slopes, containing the subsurface velocity information, have been widely used to accomplish common time-domain seismic processing, imaging and velocity estimation. In this paper, we propose a method for velocity analysis with probability density function (PDF) related to local event slopes. We first estimate local event slopes with phase information in the Fourier domain. An adaptive filter is applied to improve the performance of slopes estimator in the low signal-to-noise ratio (SNR) situation. Second, the PDF is approximated with the histogram function, which is related to attributes derived from local event slopes. As a graphical representation of the data distribution, the histogram function can be computed efficiently. By locating the ray path of the first arrival on the semblance image with straight-ray segments assumption, automatic velocity picking is carried out to establish velocity model. Unlike local event slopes based velocity estimation strategies such as averaging filters and image warping, the proposed method does not make the assumption that the errors of mapped velocity values are symmetrically distributed or that the variation of amplitude along the offset is slight. Extension of the method to prestack time-domain migration velocity estimation is also given. With synthetic and field examples, we demonstrate that our method can achieve high resolution, even in the presence of multiples, strong amplitude variations and polarity reversals.

  14. Using waste to reduce slope erosion on road embankments

    OpenAIRE

    Oña, Juan de; Osorio, Francisco

    2006-01-01

    Urban waste may be used to reduce slope erosion of highway embankments. Whereas different kinds of compost have been tested in the USA for highway revegetation, sewage sludge has been used only for agricultural purposes. This paper presents the results of research carried out in order to study the viability of the application of sewage sludge compared with compost. Test areas measuring 4 m 3 5 m were constructed on a new highway embankment with 2 : 1 and 3 : 2 side slopes in the south of Spai...

  15. Research on the seasonal snow of the Arctic Slope

    Energy Technology Data Exchange (ETDEWEB)

    Benson, C.S.

    1989-01-01

    This project deals with the seasonal snow on Alaska's Arctic Slope. Although it is concentrated on snow of the R40 project area, it is important to relate the snow cover of this area with the rest of the Arctic Slope. The goals include determination Of the amount of precipitation which comes as snow, the wind transport of this snow and its depositional pattern as influenced by drifting, the physical properties of the snow, the physical processes which operate in it, the proportions of it which go into evaporation, infiltration and runoff, and the biological role of the snow cover.

  16. Slope Stability Analysis by Shear Strength Reduction Method.

    Directory of Open Access Journals (Sweden)

    Nima Farshidfar

    2015-01-01

    Full Text Available This research uses the shear strength reduction method to study soil slopes stability. In this method shear strength is considered to be reduced as less as failure occurs. It uses Plaxis, which is capable of calculating deformations rates and safety factors by gaining geometry data of a problem and soil specifications and using the finite element method (FEM. The analysis is performed at both static and pseudo-static modes. The effects of different parameters on slopes stability are shown by performing several analyses. Finally, the analyses performed by this method are compared with the ones obtained by finite difference method (FDM.

  17. Spatial distribution models of erosion on slopes cultivated with vineyards

    International Nuclear Information System (INIS)

    Soils cultivated with vineyards have high rates of erosion. In the Mediterranean area, this is related to the environmental characteristics and the management of cultivation techniques. Indeed, in this region the rainfall intensity and the location of vineyards on slopes favour the erosive activity of runoff. The total area of vineyards in La Rioja (Spain) is currently almost 40,000 ha. Vineyards are located on hillsides between 400 and 60 m.a.s.l. Of the vineyards of La Rioja 81,7% are planted on slopes with a gradient between 3 degree centigrade and 9 degree centigrade. (Author) 5 refs.

  18. Morphodynamics and slope stability at Mergui Ridge, off western Thailand

    Science.gov (United States)

    Schwab, J.; Gross, F.; Krastel, S.; Jintasaeranee, P.; Bunsomboonsakul, S.; Winkelmann, D.; Weinrebe, W.

    2012-04-01

    2D seismic data from the top and the western slope of the Mergui Ridge (200 km off the Thai west coast) have been acquired during MASS cruise III in January 2011 in water depths between 300 and 2200 m. The Mergui Ridge is a part of the outer shelf slope off the Thai-Malay Peninsula and forms the eastern boundary of the East Andaman Basin. Structural features in the working area include faulted older slope sediments at the transition from Mergui Ridge to East Andaman Basin that are onlapping on the (acoustic) basement of Mergui Ridge. At their top these sediments are bordered by a pronounced erosive unconformity. Younger sedimentary units on top include three E-W elongated carbonate platforms. Moreover, drift sediments are deposited on top of the ridge, comprising features such as large scale sediment waves and moats around the platforms indicating transport and reworking of the sediments. These sediments are thinning towards the edge of the ridge where a zone of non-sedimentation prevails. In the East Andaman Basin younger sediments comprise disturbed and partially faulted units that are overlain by plastered drifts with increasing thickness towards south, where pronounced sediment waves within the drifts may indicate slope normal sediment transport by bottom currents. At the basin ridge transition, within the drift sediments on top of Mergui Ridge, and at the edge of the ridge several smaller scale mass transport deposits were identified. These MTDs indicate a general instability of the slope. Instability and general morphology of the slope may result from long-term tectonic processes such as extension due to backarc basin formation in the Andaman Sea basin. Moreover, phases of uplift, erosion and subsidence may have contributed to faulting and deformation of older units in our working area. Ongoing tectonics might still cause deformation and instability. In addition, bottom currents may presently play an important role concerning morphodynamic development by transporting and reworking drift sediment units and thereby shaping their morphology by along slope transport on top of the Mergui Ridge and slope normal transport in the East Andaman Basin.

  19. Air quality in bedded mono-slope beef barns

    Science.gov (United States)

    Bedded mono-slope barns are becoming more common in the upper Midwest. Because these are new facilities, little research has been published regarding environmental quality, building management and animal performance in these facilities. A team of researchers from South Dakota State University, USDA ...

  20. 30 CFR 785.15 - Steep slope mining.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Steep slope mining. 785.15 Section 785.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR SURFACE COAL MINING AND RECLAMATION OPERATIONS PERMITS AND COAL EXPLORATION SYSTEMS UNDER REGULATORY...

  1. 30 CFR 716.2 - Steep-slope mining.

    Science.gov (United States)

    2010-07-01

    ..., residential or public land uses of 30 CFR 715.13 has been achieved except for the requirement at § 715.13(d)(3... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Steep-slope mining. 716.2 Section 716.2 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INITIAL...

  2. Overtopping And Rear Slope Stabillity Of Reshaping Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk; Lykke Andersen, Thomas

    2003-01-01

    An experimental study of overtopping and rear slope stability of reshaping breakwaters has been carried out. The variation of those two parameters with crest width, crest freeboard and sea state was investigated. The tests showed that the variation in overtopping discharge with crest freeboard was...... overtopping and rear side damage....

  3. Late Holocene Radiocarbon Variability in Northwest Atlantic Slope Waters

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, O; Edinger, E; Guilderson, T P; Ghaleb, B; Risk, M J; Scott, D B

    2008-08-15

    Deep-sea gorgonian corals secrete a 2-part skeleton of calcite, derived from dissolved inorganic carbon at depth, and gorgonin, derived from recently fixed and exported particulate organic matter. Radiocarbon contents of the calcite and gorgonin provide direct measures of seawater radiocarbon at depth and in the overlying surface waters, respectively. Using specimens collected from Northwest Atlantic slope waters, we generated radiocarbon records for surface and upper intermediate water layers spanning the pre- and post bomb-{sup 14}C eras. In Labrador Slope Water (LSW), convective mixing homogenizes the pre-bomb {Delta}{sup 14}C signature (-67 {+-} 4{per_thousand}) to at least 1000 m depth. Surface water bomb-{sup 14}C signals were lagged and damped (peaking at {approx} +45{per_thousand} in the early 1980s) relative to other regions of the northwest Atlantic, and intermediate water signals were damped further. Off southwest Nova Scotia, the vertical gradient in {Delta}{sup 14}C is much stronger. In surface water, pre-bomb {Delta}{sup 14}C averaged -75 {+-} 5{per_thousand}. At 250-475 m depth, prebomb {Delta}{sup 14}C oscillated quasi-decadally between -80 and -100{per_thousand}, likely reflecting interannual variability in the presence of Labrador Slope Water vs. Warm Slope Water (WSW). Finally, subfossil corals reveal no systematic changes in vertical {Delta}{sup 14}C gradients over the last 1200 years.

  4. Stability Analysis of Nonlinear Systems with Slope Restricted Nonlinearities

    OpenAIRE

    Xian Liu; Jiajia Du; Qing Gao

    2014-01-01

    The problem of absolute stability of Lur'e systems with sector and slope restricted nonlinearities is revisited. Novel time-domain and frequency-domain criteria are established by using the Lyapunov method and the well-known Kalman-Yakubovich-Popov (KYP) lemma. The criteria strengthen some existing results. Simulations are given to illustrate the efficiency of the results.

  5. STABILITY OF LINED SLOPES AT LANDFILLS AND SURFACE IMPOUNDMENTS

    Science.gov (United States)

    This report describes the results of slope stability analyses, laboratory tests to measure the frictional properties of various interfaces that may be used in landfills and surface impoundments, and larger-scale tests to verify the data from laboratory tests. Several cases of slo...

  6. Experimental research on stability of covering blocks for sloping banks

    International Nuclear Information System (INIS)

    In the case of constructing thermal and nuclear power stations facing open seas, usually the harbors for unloading fuel and others are constructed. In Japan, breakwaters are installed in the places of relatively shallow depth less than 20 m, and in such case, the sloping banks having the covering material of wave-controlling blocks made of concrete are mostly adopted as those are excellent in their function and economical efficiency, and are advantageous in the maintenance and management. Sloping banks are of such type that wave-controlling blocks cover the vertical front face of nonpermeating caissons, and the same type was adopted for breakwaters and others in Onagawa Nuclear Power Station, Tohoku Electric Power Co., Inc. As for the wave-controlling blocks, tetrapods and shake blocks were used. One of the most important problems in the design of sloping banks is how to estimate the stability of wave controlling blocks. In this paper, the results of the examination by hydraulic model experiment on the stability of covering blocks are reported, which are useful as the basic data for the rational and economical design of sloping banks. The experimental setup and a model bank, the generation of experimental waves and their characteristics, the experimental conditions and experimental method, and the results are reported. (Kako, I.)

  7. Slope failure on Eros- Implications for regolith properties

    Science.gov (United States)

    Barnouin-Jha, O. S.; Murchie, S.; Cheng, A.; Robinson, M.

    2001-12-01

    The physical properties of regolith record processes important in the surface evolution of asteroids. For example, grain size is affected by the rates and style of cratering, and in turn affects spectral properties. In this study, we combine results acquired from the NEAR laser rangefinder (NLR) and the multispectral imager (MSI) to gain insight into physical characteristics of the regolith. By comparing the most recent NLR shape model to MSI albedo maps of Eros, we can determine the regional slope at which regolith fails. High albedos have been identified by the MSI team primarily in regions of steep slope, and attributed to exposure of the subsurface by mass-wasting processes. We determine the angles at which slope failure occurs by mapping individual NLR transects through high albedo regions visible in the MSI images, and use slope stability analyses to estimate the range of regolith grain sizes required to obtain failure at the observed angle. Preliminary results suggest that the regolith of Eros associated with these failures is coarse and possibly gravel-sized.

  8. Data compression by a decreasing slope-threshold test

    Science.gov (United States)

    Kleinrock, L.

    1973-01-01

    Resolution can be obtained at large compression ratios with method for selecting data points for transmission by telemetry in television compressed-data system. Test slope of raw data stream and compare it to symmetric pair of decreasing thresholds. When either threshold is exceeded, data are sampled and transmitted; thresholds are reset, and test begins again.

  9. THE SLOPE OF THE BARYONIC TULLY-FISHER RELATION

    International Nuclear Information System (INIS)

    We present the results of a baryonic Tully-Fisher relation (BTFR) study for a local sample of relatively isolated disk galaxies. We derive a BTFR with a slope near 3 measured over about 4 dex in baryon mass for our combined H I and bright spiral disk samples. This BTFR is significantly flatter and has less scatter than the TFR (stellar mass only) with its slope near 4 reported for other samples and studies. A BTFR slope near 3 is in better agreement with the expected slope from simple ?CDM cosmological simulations that include both stellar and gas baryons. The scatter in the TFR/BTFR appears to depend on W20: galaxies that rotate slower have more scatter. The atomic gas-to-stars ratio shows a break near W20 = 250 km s-1 probably associated with a change in star formation efficiency. In contrast, the absence of such a break in the BTFR suggests that this relation was probably set at the main epoch of baryon dissipation rather than as a product of later galactic evolution.

  10. The Slope of the Baryonic Tully-Fisher Relation

    Science.gov (United States)

    Gurovich, Sebastián; Freeman, Kenneth; Jerjen, Helmut; Staveley-Smith, Lister; Puerari, Ivânio

    2010-09-01

    We present the results of a baryonic Tully-Fisher relation (BTFR) study for a local sample of relatively isolated disk galaxies. We derive a BTFR with a slope near 3 measured over about 4 dex in baryon mass for our combined H I and bright spiral disk samples. This BTFR is significantly flatter and has less scatter than the TFR (stellar mass only) with its slope near 4 reported for other samples and studies. A BTFR slope near 3 is in better agreement with the expected slope from simple ?CDM cosmological simulations that include both stellar and gas baryons. The scatter in the TFR/BTFR appears to depend on W 20: galaxies that rotate slower have more scatter. The atomic gas-to-stars ratio shows a break near W 20 = 250 km s-1 probably associated with a change in star formation efficiency. In contrast, the absence of such a break in the BTFR suggests that this relation was probably set at the main epoch of baryon dissipation rather than as a product of later galactic evolution.

  11. Slope histogram distribution-based parametrisation of Martian geomorphic features

    Science.gov (United States)

    Balint, Zita; Székely, Balázs; Kovács, Gábor

    2014-05-01

    The application of geomorphometric methods on the large Martian digital topographic datasets paves the way to analyse the Martian areomorphic processes in more detail. One of the numerous methods is the analysis is to analyse local slope distributions. To this implementation a visualization program code was developed that allows to calculate the local slope histograms and to compare them based on Kolmogorov distance criterion. As input data we used the digital elevation models (DTMs) derived from HRSC high-resolution stereo camera image from various Martian regions. The Kolmogorov-criterion based discrimination produces classes of slope histograms that displayed using coloration obtaining an image map. In this image map the distribution can be visualized by their different colours representing the various classes. Our goal is to create a local slope histogram based classification for large Martian areas in order to obtain information about general morphological characteristics of the region. This is a contribution of the TMIS.ascrea project, financed by the Austrian Research Promotion Agency (FFG). The present research is partly realized in the frames of TÁMOP 4.2.4.A/2-11-1-2012-0001 high priority "National Excellence Program - Elaborating and Operating an Inland Student and Researcher Personal Support System convergence program" project's scholarship support, using Hungarian state and European Union funds and cofinances from the European Social Fund.

  12. Evaluation of slope stability with respect to snowpack spatial variability

    Science.gov (United States)

    Gaume, J.; Schweizer, J.; Herwijnen, A.; Chambon, G.; Reuter, B.; Eckert, N.; Naaim, M.

    2014-09-01

    The evaluation of avalanche release conditions constitutes a great challenge for risk assessment in mountainous areas. The spatial variability of snowpack properties has an important impact on snow slope stability and thus on avalanche formation, since it strongly influences failure initiation and crack propagation in weak snow layers. Hence, the determination of the link between these spatial variations and slope stability is very important, in particular, for avalanche public forecasting. In this study, a statistical-mechanical model of the slab-weak layer (WL) system relying on stochastic finite element simulations is used to investigate snowpack stability and avalanche release probability for spontaneously releasing avalanches. This model accounts, in particular, for the spatial variations of WL shear strength and stress redistribution by elasticity of the slab. We show how avalanche release probability can be computed from release depth distributions, which allows us to study the influence of WL spatial variations and slab properties on slope stability. The importance of smoothing effects by slab elasticity is verified and the crucial impact of spatial variation characteristics on the so-called knock-down effect on slope stability is revisited using this model. Finally, critical length values are computed from the simulations as a function of the various model parameters and are compared to field data obtained with propagation saw tests.

  13. The Psychological Mechanism of the Slippery Slope Argument

    Science.gov (United States)

    Corner, Adam; Hahn, Ulrike; Oaksford, Mike

    2011-01-01

    Slippery slope arguments (SSAs) have a bad philosophical reputation. They seem, however, to be widely used and frequently accepted in many legal, political, and ethical contexts. Hahn and Oaksford (2007) argued that distinguishing strong and weak SSAs may have a rational basis in Bayesian decision theory. In this paper three experiments…

  14. Granular flow behavior at sharp changes in slope

    Science.gov (United States)

    Crosta, Giovanni; De Blasio, Fabio; Locatelli, Michele

    2015-04-01

    This study extends some recent experiments and analyses performed by the authors to examine the behavior of granular flows along path characterised by sharp changes in slope. In particular, various series of experiments along a bi-linear broken slope (an inclined initial sector followed by a horizontal one) have been completed using a uniform (Hostun, 0.32 mm) sand and a uniform fine gravel (2 mm grains). 60 new have been performed by releasing different volumes (1.5, 2.1 and 5.1 L) on surfaces characterized by different slope angles (35-60°), type of materials (wood and plexiglass), with or without an erodible layer (sand), or in presence of a shallow water pond (0.5 cm). These geometrical features are typical of many large rock and snow avalanches, rock falls and of chalk flows. The latter are usually typical of coastal cliffs where a shallow water environment is typical. The evolution of the flow has been monitored through a laser profilometer at 120 Hz sampling frequency and high speed camera, and in this way it has been possible to follow the evolution of the flow and deposition, and to analyse the change in deposition mode at varying the slope angle, the material and the basal friction. This is an extremely interesting development in the study of the evolution of the deposition and of the final morphology typical of such phenomena, and can support the testing of numerical models. Propagation and deposition occur forward or backward accordingly to the slope angle and the basal friction. Forward movement and deposition occur at high slope angles and with low basal friction. The opposite is true for the backward deposition. The internal "layering" within the deposit is also strongly controlled by the combination of such parameters. The time evolution of the flow allowed to determine the velocity of flow and the mode of deposition through the analysis of the change in thickness, position of the front and of the flow tail. Presence of water reduces the runout of the sand on the horizontal sector of the path, whereas the opposite seems true for the gravel. In these cases, as already shown by the authors (Crosta et al., submitted), a partial reflection of the flow occurs and the same holds true when a shallow water reservoir exists. Furthermore, a sort of hydroplaning phenomenon occurs which controls the initial part of the expansion along the subhorizontal sector of the path. Results of the experimental campaign have been compared against those from simple analytical models which assume the energy loss at the slope break and numerical simulations performed by a FEM-ALE (2D and fully 3D) modeling.

  15. Consequence assessment of large rock slope failures in Norway

    Science.gov (United States)

    Oppikofer, Thierry; Hermanns, Reginald L.; Horton, Pascal; Sandøy, Gro; Roberts, Nicholas J.; Jaboyedoff, Michel; Böhme, Martina; Yugsi Molina, Freddy X.

    2014-05-01

    Steep glacially carved valleys and fjords in Norway are prone to many landslide types, including large rockslides, rockfalls, and debris flows. Large rockslides and their secondary effects (rockslide-triggered displacement waves, inundation behind landslide dams and outburst floods from failure of landslide dams) pose a significant hazard to the population living in the valleys and along the fjords shoreline. The Geological Survey of Norway performs systematic mapping of unstable rock slopes in Norway and has detected more than 230 unstable slopes with significant postglacial deformation. This large number necessitates prioritisation of follow-up activities, such as more detailed investigations, periodic displacement measurements, continuous monitoring and early-warning systems. Prioritisation is achieved through a hazard and risk classification system, which has been developed by a panel of international and Norwegian experts (www.ngu.no/en-gb/hm/Publications/Reports/2012/2012-029). The risk classification system combines a qualitative hazard assessment with a consequences assessment focusing on potential life losses. The hazard assessment is based on a series of nine geomorphological, engineering geological and structural criteria, as well as displacement rates, past events and other signs of activity. We present a method for consequence assessment comprising four main steps: 1. computation of the volume of the unstable rock slope; 2. run-out assessment based on the volume-dependent angle of reach (Fahrböschung) or detailed numerical run-out modelling; 3. assessment of possible displacement wave propagation and run-up based on empirical relations or modelling in 2D or 3D; and 4. estimation of the number of persons exposed to rock avalanches or displacement waves. Volume computation of an unstable rock slope is based on the sloping local base level technique, which uses a digital elevation model to create a second-order curved surface between the mapped extent of the unstable rock slope. This surface represents the possible basal sliding surface of an unstable rock slope. The elevation difference between this surface and the topographic surface estimates the volume of the unstable rock slope. A tool has been developed for the present study to adapt the curvature parameters of the computed surface to local geological and structural conditions. The obtained volume is then used to define the angle of reach of a possible rock avalanche from the unstable rock slope by using empirical derived values of angle of reach vs. volume relations. Run-out area is calculated using FlowR; the software is widely used for run-out assessment of debris flows and is adapted here for assessment of rock avalanches, including their potential to ascend opposing slopes. Under certain conditions, more sophisticated and complex numerical run-out models are also used. For rock avalanches with potential to reach a fjord or a lake the propagation and run-up area of triggered displacement waves is assessed. Empirical relations of wave run-up height as a function of rock avalanche volume and distance from impact location are derived from a national and international inventory of landslide-triggered displacement waves. These empirical relations are used in first-level hazard assessment and where necessary, followed by 2D or 3D displacement wave modelling. Finally, the population exposed in the rock avalanche run-out area and in the run-up area of a possible displacement wave is assessed taking into account different population groups: inhabitants, persons in critical infrastructure (hospitals and other emergency services), persons in schools and kindergartens, persons at work or in shops, tourists, persons on ferries and so on. Exposure levels are defined for each population group and vulnerability values are set for the rock avalanche run-out area (100%) and the run-up area of a possible displacement wave (70%). Finally, the total number of persons within the hazard area is calculated taking into account exposure and vulnerability. The method for conse

  16. Influences of Holocene sea level, regional tectonics, and fluvial, gravity and slope currents induced sedimentation on the regional geomorphology of the continental slope off northwestern India

    Digital Repository Service at National Institute of Oceanography (India)

    Chauhan, O.S.; Almeida, F.

    the Holocene sea level. The Bombay high area has slope breaks between 400 and 600 m, whereas off Saurashtra steep breaks in the slope occur between 560 and 960 m depth. Further southwards, at the slope, elevations and depressions are present. Variations...

  17. HIRESSS: a physically based slope stability simulator for HPC applications

    Directory of Open Access Journals (Sweden)

    G. Rossi

    2013-01-01

    Full Text Available HIRESSS (HIgh REsolution Slope Stability Simulator is a physically based distributed slope stability simulator for analyzing shallow landslide triggering conditions in real time and on large areas using parallel computational techniques. The physical model proposed is composed of two parts: hydrological and geotechnical. The hydrological model receives the rainfall data as dynamical input and provides the pressure head as perturbation to the geotechnical stability model that computes the factor of safety (FS in probabilistic terms. The hydrological model is based on an analytical solution of an approximated form of the Richards equation under the wet condition hypothesis and it is introduced as a modeled form of hydraulic diffusivity to improve the hydrological response. The geotechnical stability model is based on an infinite slope model that takes into account the unsaturated soil condition. During the slope stability analysis the proposed model takes into account the increase in strength and cohesion due to matric suction in unsaturated soil, where the pressure head is negative. Moreover, the soil mass variation on partially saturated soil caused by water infiltration is modeled.

    The model is then inserted into a Monte Carlo simulation, to manage the typical uncertainty in the values of the input geotechnical and hydrological parameters, which is a common weak point of deterministic models. The Monte Carlo simulation manages a probability distribution of input parameters providing results in terms of slope failure probability. The developed software uses the computational power offered by multicore and multiprocessor hardware, from modern workstations to supercomputing facilities (HPC, to achieve the simulation in reasonable runtimes, compatible with civil protection real time monitoring.

    A first test of HIRESSS in three different areas is presented to evaluate the reliability of the results and the runtime performance on large areas.

  18. Recent slope mobilizations in the Storegga Slide area

    Science.gov (United States)

    Berndt, C.; Crutchley, G.; Karstens, J.; Dumke, I.; Duennbier, K.

    2012-12-01

    With ~3500 km3 of mobilized material the Storegga Slide off mid-Norway is one of the largest known sub-marine slope failures. It occurred approximately 8150 years ago and there is strong evidence suggesting that the slide caused a large tsunami that propagated through the North Atlantic and affected the coasts of Norway, Iceland and the U.K. In the Nyegga area along the northern side wall of the slide numerous shallow faults exist. These faults detach within the top 100 m below the sea floor at various stratigraphic levels below, at, and above the main slide plain of the Storegga Slide. Previous studies proposed that these faults are evidence for partial slope movements during the Storegga Slide event indicating that the adjacent slopes were deformed due to the stress variations caused by the Storegga Slide. New high-resolution Parasound data that we have collected in May 2012 onboard RV Meteor show offsets of reflectors that are buried less than 3 m below the sea floor. Assuming that the sedimentation rates derived from a near-by Marion Dufresne sediment core, can be extrapolated to the study area, these reflector offsets suggest that the faults are younger than the Storegga Slide. Given a several million year-long history of repeated slope failures in the area it is important to obtain more precise dates for the activity of the faults in order to assess if these faults can be used as an indicator for future slope failures in the area or if they are the result of small-scale adjustments of the head wall topography in the wake of the Storegga Slide.

  19. The dependence of sheet erosion velocity on slope angle

    Directory of Open Access Journals (Sweden)

    Chernyshev Sergey Nikolaevich

    2014-09-01

    Full Text Available The article presents a method for estimating the erosion velocity on forested natural area. As a research object for testing the methodology the authors selected Neskuchny Garden - a city Park on the Moskva river embankment, named after the cognominal Palace of Catherine's age. Here, an almost horizontal surface III of the Moskva river terrace above the flood-plain is especially remarkable, accentuated by the steep sides of the ravine parallel to St. Andrew's, but short and nameless. The crests of the ravine sides are sharp, which is the evidence of its recent formation, but the old trees on the slopes indicate that it has not been growing for at least 100 years. Earlier Russian researchers defined vertical velocity of sheet erosion for different regions and slopes with different parent (in relation to the soil rocks. The comparison of the velocities shows that climatic conditions, in the first approximation, do not have a decisive influence on the erosion velocity of silt loam soils. The velocities on the shores of Issyk-Kul lake and in Moscow proved to be the same. But the composition of the parent rocks strongly affects the sheet erosion velocity. Even low-strength rock material reduces the velocity by times. Phytoindication method gives a real, physically explainable sheet erosion velocities. The speed is rather small but it should be considered when designing long-term structures on the slopes composed of dispersive soils. On the slopes composed of rocky soils sheet erosion velocity is so insignificant that it shouldn't be taken into account when designing. However, there may be other geological processes, significantly disturbing the stability of slopes connected with cracks.

  20. Distribution of solar radiation including slope effect in South Korea

    Science.gov (United States)

    Baek, Shin Chul; Park, Jong-Hwa; Na, Sang Il; Park, Jin-Ki

    2012-10-01

    Agriculture and ecosystems are very solar radiation-sensitive making them useful for monitoring the impact on future food production. Accurate solar radiation data are necessary to evaluate major physiological reaction of crops and an impact of climate change. For most upland crops and orchard plants growing in sloping terrain, however the meteorological data are often limited. Considering the scarcity of detailed meteorological data around the country, there is a need for methods which can estimate reference solar radiation with limited data. This study describes a method to estimate monthly average daily solar radiation of considering the slope distribution. It was calculated using the 2010's meteorological data and KT method which is entered DEM and spatial interpolation data of both monthly average daily extraterrestrial radiation and monthly average daily radiation on land surface. Extracted slope from the DEM in South Korea include range between 0? to 77? and most of the land is mountainous. According to the slope, solar radiation characteristic show to have high value in spring season (April) relatively other season. Summer season interrupt to reach direct solar radiation, cause is unstable atmospheric and cloud. The distributions of monthly accumulated solar radiation indicated that differences caused by the topography effect are more important in winter than in other season because of the dependency on the solar altitude angle and duration of sunshine. Result of KT method is confirmed to overestimate monthly average 1.38MJ?m􀬶?day than solar radiation weather station measurement values. Solar radiation of slope error value will need continuous research and correction through both fields survey and topography factor.

  1. The Storage Process for Landslides inner Slope During Rainfall

    Science.gov (United States)

    Wang, Chao-Wen; Yoshimi, Kazuhiro; Yamada, Tadashi

    2015-04-01

    In general, there are two main triggering reasons of landslides, one is earthquake and the other is rainfall. And during rainfall, the storage change inner the slope is very difficult to measure. It depends on the soil and geomorphology features not to mention the storage change on the whole watershed. Therefore in this study, we will focus on the storage process of rainfall-induced landslides. The storage process means the rainfall infiltrating into slopes, and its volume change of the water inner the slopes during every rainfall event. In this study, Yamada model would be used to calculate this process. This model combines the tank model and storage model to evaluate the rainfall-storage-runoff process for a watershed by using the rainfall and discharge data. This model will be used to estimate the possible storage change during rainfall and the most important is the observation data of the rainfall and discharge. The rainfall data means the input data and the discharge is the output data. It means that according to the input and output, the change of the storage volume could be estimated. Yamada model first used the kinematic wave model to conduct the relation of rainfall-runoff equation, and then the middle process of the rainfall-runoff can be inverse-estimated. However the parameters of the soil layers are very difficult to measure and decide for whole watershed. Therefore in this paper, Gauss-Newton method has used to estimate the possible parameters by input-rainfall and output-discharge data. And finally the storage process inner the slope during rainfall can be evaluated. And the estimation model for the process with time and region characteristics of watersheds also can be defined by using Yamada model. And in the future, the results of this storage process can apply to the analysis of slope stability and furthermore the early warning application.

  2. Evaluation of topography site effect in slope stability under dynamic loading

    OpenAIRE

    Nguyen, Hieu Toan; Fleurisson, Jean-Alain; Roger COJEAN

    2013-01-01

    The slope topography site effect is a phenomenon in which the seismic ground motion is amplified at the crest of the slope. This effect can damage structures and can even cause slope instabilities. The aim of this study is to explore the impact of slope geomorphology parameters on topographic site effects. A dimensionless factor, the ratio of the slope height to the seismic wavelength is identified as a critical parameter. Numerical simulations resulting in the seismic response of a uniform s...

  3. Department of Energy Arm Facilities on the North Slope of Alaska and Plans for a North Slope "Mega-Site"

    Science.gov (United States)

    Ivey, M.; Verlinde, J.

    2014-12-01

    The U.S. Department of Energy (DOE), through its scientific user facility, the Atmospheric Radiation Measurement (ARM) Climate Research Facility, provides scientific infrastructure and data to the international Arctic research community via its research sites located on the North Slope of Alaska. The DOE ARM Program has operated an atmospheric measurement facility in Barrow, Alaska, since 1998. Major upgrades to this facility, including scanning radars, were added in 2010. Facilities and infrastructure to support operations of unmanned aerial systems for science missions in the Arctic and North Slope of Alaska were established at Oliktok Point Alaska in 2013. Tethered instrumented balloons will be used in the near future to make measurements of clouds in the boundary layer including mixed-phase clouds. The Atmospheric Radiation Measurement (ARM) Climate Research Facility is implementing "mega-sites" at the Southern Great Plains and North Slope of Alaska sites. Two workshops were held to gather input from the scientific community on these mega-sites. The NSA workshop was held September 10 and 11 in the Washington DC area. The workshops included discussions of additional profiling remote sensors, detailed measurements of the land-atmosphere interface, aerial operations to link the Barrow and Oliktok sites, unmanned aerial system measurements, and routine large eddy simulation model runs. The "mega-sites" represent a significant new scientific and infrastructure investment by DOE Office of Science, Office of Biological and Environmental Research. This poster will present information on plans for a North Slope "Megasite" as well as new opportunities for members of the arctic research community to make atmospheric measurements using unmanned aerial systems or tethered balloons in conjunction with the DOE ARM facilities on the North Slope of Alaska.

  4. Area utilization efficiency of a sloping heliostat system for solar concentration.

    Science.gov (United States)

    Wei, L Y

    1983-02-15

    Area utilization efficiency (AUE) is formulated for a sloping heliostat system facing any direction. The effects of slope shading, incidence factor, sun shading, and tower blocking by the mirrors are all taken into account. Our results show that annually averaged AUEs calculated for heliostat systems (1) increase with tower height at low slope angles but less rapidly at high slopes, (2) increase monotonically with slope angle and saturate at large slopes for systems facing due south, (3) reach a maximum at a certain slope for systems facing other directions than due south, and (4) drop sharply at slopes greater than a certain value for systems facing due east or west due to slope shading effect. The results are useful for solar energy collection on nonflat terrains. PMID:18195827

  5. Breaking of Waves over a Steep Bottom Slope

    DEFF Research Database (Denmark)

    Jensen, Morten S.

    2004-01-01

    The thesis deals with the wave breaking process of waves propagating over a steep submerged bottom slope. The amount of energy dissipated in the wave breaking process is focused upon. An extensive number of experimental tests (>400) using regular and irregular waves breaking over a simulated reef in the hydraulic laboratory are performed. Based on the experimental tests several formulae developed. Formulae are capable of predicting the transmitted wave height and wave energy flux, respectively. Furthermore, a numerical wave model based on the extended Mild-Slope equation has been developed. The model is capable of generating progressive irregular waves. Wave breaking has been included using a modification of the Battjes and Janssen [1978] periodic bore approach. The results from this study be applicable in the design of coastal structures as submerged breakwaters or artificial reefs.

  6. HIGH FIELD Q-SLOPE AND THE BAKING EFFECT

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [JLAB

    2009-11-01

    The performance of SRF cavities made of bulk Nb at high fields (peak surface magnetic field greater than about 90 mT) is characterized by exponentially increasing RF losses (high-field Q-slope), in the absence of field emission, which are often mitigated by a low temperature (100-140 °C, 12-48h) baking. In this contribution, recent experimental results and phenomenological models to explain this effect will be briefly reviewed. New experimental results on the high-field Q-slope will be presented for cavities that had been heat treated at high temperature in the presence of a small partial pressure of nitrogen. Improvement of the cavity performances have been obtained, while surface analysis measurements on Nb samples treated with the cavities revealed significantly lower hydrogen concentration than for samples that followed standard cavity treatments.

  7. Hydraulic Characteristics of a Stepped-slope Floating Breakwater

    International Nuclear Information System (INIS)

    A stepped-slope floating breakwater is developed to provide wave protection to small ports and harbours. The width of the structure can be enhanced by increasing the number of breakwater units that are placed side-by-side to each other. This produces three types of test model, i.e. single-row, double-row and triple-row breakwaters. The test models have been tested in monochromatic waves in a wave flume to determine their hydraulic performance in various wave conditions. The incident and reflected wave profiles in the vicinity of the test models are recorded and analysed by using moving-probe method. The hydraulic performance of the test models are quantified by the coefficients of transmission, reflection and energy loss. The experimental results showed that the stepped-slope floating breakwater is an effective anti-reflection structure and a reasonably good wave attenuator.

  8. Surface Slope Metrology on Deformable Soft X-ray Mirrors

    International Nuclear Information System (INIS)

    We report on the current state of surface slope metrology on deformable mirrors for soft x-rays at the Advanced Light Source (ALS). While we are developing techniques for in situ at-wavelength tuning, we are refining methods of ex situvisible-light optical metrology to achieve sub-100-nrad accuracy. This paper reports on laboratory studies, measurements and tuning of a deformable test-KB mirror prior to its use. The test mirror was bent to a much different optical configuration than its original design, achieving a 0.38 micro-radian residual slope error. Modeling shows that in some cases, by including the image conjugate distance as an additional free parameter in the alignment, along with the two force couples, fourth-order tangential shape errors (the so-called bird shape) can be reduced or eliminated.

  9. Surface Slope Metrology on Deformable Soft X-ray Mirrors

    International Nuclear Information System (INIS)

    We report on the current state of surface slope metrology on deformable mirrors for soft x-rays at the Advanced Light Source (ALS). While we are developing techniques for in situ at-wavelength tuning, we are refining methods of ex situ visible-light optical metrology to achieve sub-100-nrad accuracy. This paper reports on laboratory studies, measurements and tuning of a deformable test-KB mirror prior to its use. The test mirror was bent to a much different optical configuration than its original design, achieving a 0.38 micro-radian residual slope error. Modeling shows that in some cases, by including the image conjugate distance as an additional free parameter in the alignment, along with the two force couples, fourth-order tangential shape errors (the so-called bird shape) can be reduced or eliminated.

  10. Integration of Indoor Ski Slopes into the Urban Recreation System

    Directory of Open Access Journals (Sweden)

    Inga Urbonait?

    2011-03-01

    Full Text Available Indoor ski slope is an innovative type of active indoor recreation. This new urban character is simulating the concept of mountain ski resort and is considered to be a strong attraction point all year-round. Due to a big scale and complexity, sustainable integration into an urban context should be very carefully considered. Economical, social, environmental and aesthetic impact on surrounding territories is an important factor to be evaluated. International practice shows that the appropriate integration of the above mentioned typology into urban parks increase their popularity and use of the recreation zone. On the other hand, the alien architecture and egocentric dominance of complexes can cause conflict with the existing urban territories and natural environment. Having indoor ski slopes in mind at the stages of regional and town territorial planning is an important point. Only complex development can bring positive results for sustainable town development, town economy, tourism and social life. Article in Lithuanian

  11. Slippery slopes in flat countries--a response.

    Science.gov (United States)

    van Delden, J J

    1999-02-01

    In response to the paper by Keown and Jochemsen in which the latest empirical data concerning euthanasia and other end-of-life decisions in the Netherlands is discussed, this paper discusses three points. The use of euthanasia in cases in which palliative care was a viable alternative may be taken as proof of a slippery slope. However, it could also be interpreted as an indication of a shift towards more autonomy-based end-of-life decisions. The cases of non-voluntary euthanasia are a serious problem in the Netherlands and they are only rarely justifiable. However, they do not prove the existence of a slippery slope. Persuading the physician to bring euthanasia cases to the knowledge of the authorities is a problem of any euthanasia policy. The Dutch notification procedure has recently been changed to reduce the underreporting of cases. However, many questions remain. PMID:10070634

  12. Desirable plant root traits for protecting unstable slopes against landslides

    Science.gov (United States)

    Stokes, A.; Atger, C.; Bengough, G.; Fourcaud, T.; Sidle, R. C.

    2009-04-01

    A trait is defined as a distinct, quantitative property of organisms, usually measured at the individual level and used comparatively across species. Plant quantitative traits are extremely important for understanding the local ecology of any site. Plant height, architecture, root depth, wood density, leaf size and leaf nitrogen concentration control ecosystem processes and define habitat for other taxa. An engineer conjecturing as to how plant traits may directly influence physical processes occurring on sloping land just needs to consider how e.g. canopy architecture and litter properties influence the partitioning of rainfall among interception loss, infiltration and runoff. Plant traits not only influence abiotic processes occurring at a site, but also the habitat for animals and invertebrates. Depending on the goal of the landslide engineer, the immediate and long-term effects of plant traits in an environment must be considered if a site is to remain viable and ecologically successful. When vegetation is considered in models of slope stability, usually the only root parameters taken into consideration are tensile strength and root area ratio. Root system spatial structure is not considered, although the length, orientation and diameter of roots are recognized as being of importance. Thick roots act like soil nails on slopes, reinforcing soil in the same way that concrete is reinforced with steel rods. The spatial position of these thick roots also has an indirect effect on soil fixation in that the location of thin and fine roots will depend on the arrangement of thick roots. Thin and fine roots act in tension during failure on slopes and if they cross the slip surface, are largely responsible for reinforcing soil on slopes. Therefore, the most important trait to consider initially is rooting depth. To stabilize a slope against a shallow landslide, roots must cross the shear surface. The number and thickness of roots in this zone will therefore largely determine slope stability. Rooting depth is species dependent when soil conditions are not limiting and the number of horizontal lateral roots borne on the vertical roots usually changes with depth. Therefore, the number and orientation of roots that the shear surface intersects will change significantly with rooting depth for the same plant, even for magnitudes of only several cm. Similarly, depending on the geometry of the root system, the angle at which a root crosses the shear surface can also have an influence on its resistance to pullout and breakage. The angle at which a root emerges from the parent root is dependent on root type, depth and species (when soil conditions are not limiting). Due to the physiology of roots, a root branch can be initiated at any point along a parent root, but not necessarily emerge fully from the parent root. These traits, along with others including size, relative growth rate, regeneration strategies, wood structure and strength will be discussed with regard to their influence on slope stability. How each of these traits is influenced by soil conditions and plantation techniques is also of extreme importance to the landslide engineer. The presence of obstacles in the soil, as well as compaction, affects root length and branching pattern. Roots of many species of woody plants on shallow soils also tend to grow along fractures deep into the underlying bedrock which allows roots to locate supplies of nutrient and water rich pockets. Rooting depths of herbaceous species in water-limited environments are highly correlated with infiltration depth, but waterlogged soils can asphyxiate tree roots, resulting in shallow root systems. The need to understand and integrate each of these traits for a species is not easy. Therefore, we suggest a hierarchy whereby traits are considered in order of importance, along with how external factors influence their expression over time.

  13. Alaska North Slope oil-field restoration research strategy. Manual

    International Nuclear Information System (INIS)

    The document provides a research strategy to support ecological restoration of disturbances related to oil and gas developments on the North Slope of Alaska that is mutually beneficial to the arctic ecorestoration research community and the arctic regulatory community (including at least the following entities: The U.S. Army Corps of Engineers, EPA, National Marine Fisheries, US FWS, BLM, the Alaska Department of Natural Resources, and the North Slope Borough). The purpose of this strategy is to: (1) identify major information or knowledge gaps that have inhibited restoration activities or slowed the regulatory decision process, (2) determine the potential for filling knowledge gaps through research, and (3) suggest tentative priorities for research that are based on the needs identified in steps one and two

  14. Forecasting giant, catastrophic slope collapse: lessons from Vajont, Northern Italy

    Science.gov (United States)

    Kilburn, Christopher R. J.; Petley, David N.

    2003-08-01

    Rapid, giant landslides, or sturzstroms, are among the most powerful natural hazards on Earth. They have minimum volumes of ˜10 6-10 7 m 3 and, normally preceded by prolonged intervals of accelerating creep, are produced by catastrophic and deep-seated slope collapse (loads ˜1-10 MPa). Conventional analyses attribute rapid collapse to unusual mechanisms, such as the vaporization of ground water during sliding. Here, catastrophic collapse is related to self-accelerating rock fracture, common in crustal rocks at loads ˜1-10 MPa and readily catalysed by circulating fluids. Fracturing produces an abrupt drop in resisting stress. Measured stress drops in crustal rock account for minimum sturzstrom volumes and rapid collapse accelerations. Fracturing also provides a physical basis for quantitatively forecasting catastrophic slope failure.

  15. ARRA additions to the north slope of Alaska.

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Scott (Pennsylvania State University); Cherry, Jessica (University of Alaska Fairbanks); Stuefer, Martin (University of Alaska Fairbanks); Zirzow, Jeffrey A.; Zak, Bernard Daniel; Ivey, Mark D.; Verlinde, Johannes (Pennsylvania State University)

    2010-03-01

    The U.S. Department of Energy (DOE) provides scientific infrastructure and data archives to the international Arctic research community through a national user facility, the ARM Climate Research Facility, located on the North Slope of Alaska. The ARM sites at Barrow and Atqasuk, Alaska have been collecting and archiving atmospheric data for more than 10 years. These data have been used for scientific investigation as well as remote sensing validations. Funding from the Recovery Act (American Recovery and Reinvestment Act of 2009) will be used to install new instruments and upgrade existing instruments at the North Slope sites. These instruments include: scanning precipitation radar; scanning cloud radar; automatic balloon launcher; high spectral resolution lidar; eddy correlation flux systems; and upgraded ceilometer, AERI, micropulse lidar, and millimeter cloud radar. Information on these planned additions and upgrades will be provided in our poster. An update on activities planned at Oliktok Point will also be provided.

  16. Quantitative laboratory observations of internal wave reflection on ascending slopes

    CERN Document Server

    Gostiaux, L; Didelle, H; Sommeria, J; Viboud, S; Gostiaux, Louis; Dauxois, Thierry; Didelle, Henri; Sommeria, Joel; Viboud, Samuel

    2006-01-01

    Internal waves propagate obliquely through a stratified fluid with an angle that is fixed with respect to gravity. Upon reflection on a sloping bed, striking phenomena are expected to occur close to the slope. We present here laboratory observations at moderately large Reynolds number. A particle image velocimetry (PIV) technique is used to provide time resolved velocity fields in large volumes. The generation of the second and third harmonic frequencies are clearly demonstrated in the impact zone. The mechanism for nonlinear wavelength selection is also discussed. Evanescent waves with frequency larger than the Brunt-V\\"ais\\"al\\"a frequency are detected and experimental results agree very well with theoretical predictions. The amplitude of the different harmonics after reflection are also obtained.

  17. Bioengineering Techniques for Soil Erosion Protection and Slope Stabilization

    OpenAIRE

    Georgi, Julia; Stathakopoulos, Ioannis

    2006-01-01

    The use of bio-engineering methods for soil erosion protection and slope stabilization has a long tradition. Old methods with rocks and plants, structures of timber have been used over the past centuries. Recently these old soil conservation and stabilization techniques have been rediscovered and improved. Biotechnical engineering methods have become part of geotechnical and hydraulic engineering and have helped bridge the gap between classical engineering disciplines, land use management, la...

  18. Unemployment, tax evasion and the "slippery slope" framework

    OpenAIRE

    Lisi, Gaetano

    2012-01-01

    The proposed theoretical work introduces the basic insights of the ‘slippery slope’ framework into the benchmark macroeconomic model of the labour market in order to study the relation between tax compliance (both voluntary and enforced), tax evasion and unemployment. This paper shows that the firm's decision to evade taxes also depends on trust in tax authorities, and affects one of the most important macroeconomic variables: the unemployment rate. Also, the model is able to mimic the crucia...

  19. Unraveling bed slope from relative roughness in initial sediment motion

    Science.gov (United States)

    Prancevic, Jeff P.; Lamb, Michael P.

    2015-03-01

    Understanding incipient sediment transport is crucial for predicting landscape evolution, mitigating flood hazards, and restoring riverine habitats. Observations show that the critical Shields stress increases with increasing channel bed slope, and proposed explanations for this counterintuitive finding include enhanced form drag from bed forms, particle interlocking across the channel width, and large bed sediment relative to flow depth (relative roughness). Here we use scaled flume experiments with variable channel widths, bed slopes, and particle densities to separate these effects which otherwise covary in natural streams. The critical Shields stress increased with bed slope for both natural gravel (?s = 2.65 g/cm3) and acrylic particles (?s = 1.15 g/cm3), and adjusting channel width had no significant effect. However, the lighter acrylic particles required a threefold higher critical Shields stress for mobilization relative to the natural gravel at a fixed slope, which is unexpected because particle density is accounted for directly in the definition of Shields stress. A comparison with model predictions indicates that changes in local velocity and turbulence associated with increasing relative roughness for lighter materials are responsible for increasing the critical Shields stress in our experiments. These changes lead to concurrent changes in the hydraulic resistance and a nearly constant critical stream power value at initial motion. Increased relative roughness can explain much of the observed heightened critical Shields stresses and reduced sediment transport rates in steep channels and also may bias paleohydraulic reconstructions in environments with exotic submerged densities such as iron ore, pumice, or ice clasts on Titan.

  20. Wave Run-Up on Sloping Coastal Structures

    DEFF Research Database (Denmark)

    Rouck, J. De; Troch, P.; Ronde, J. De; Frigaard, Peter

    2001-01-01

    Wave run-up is one of the main physical processes which is taken into account in the design of the crest level of sloping coastal structures. Until recently, solely physical model results were used for the crest level design. However, prototype measurements have indicated that scale models underestimate wave run-up. Therefore wave run-up is studied in detail comparing prototype measurements and physical modelling.

  1. A generalization of Ross-Thomas' slope theory

    OpenAIRE

    Odaka, Yuji

    2009-01-01

    We give a formula of the Donaldson-Futaki invariants for certain type of semi test configurations, which essentially generalizes Ross-Thomas' slope theory. The positivity (resp. non-negativity) of those "a priori special" Donaldson-Futaki invariants implies K-stability (resp. K-semistability). We show its applicability by proving K-(semi)stability of certain polarized varieties with semi-log-canonical singularities, generalizing some results by Ross-Thomas.

  2. Relating weak layer and slab properties to snow slope stability

    OpenAIRE

    Schweizer, J.; Reuter, B.

    2014-01-01

    Snow slope stability evaluation requires considering weak layer as well as slab properties – and in particular their interaction. We developed a stability index from snow micro-penetrometer measurements and compared it to 129 concurrent point observations with the compression test (CT). The index considers the SMP-derived micro-structural strength and the additional load which depends on the hardness of the surface layers. The new quantitative measure of sta...

  3. A New Formula for Front Slope Recession of Berm Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.

    2010-01-01

    The front slope stability of breakwaters with a homogeneous berm was studied in a large number of two dimensional model tests at Aalborg University, Denmark. The results are presented together with a new formula for prediction of the berm recession which is the most important parameter for describing the reshaping. The formula has also been calibrated and validated against model test data from other researchers. The significance of the new design formula is that it predicts berm recession much b...

  4. Three-dimensional slope stability problem with a surcharge load

    Science.gov (United States)

    Cheng, Y. M.; Li, N.; Yang, X. Q.

    2015-10-01

    A semi-analytical solution for the three-dimensional stability analysis of the ultimate uniform patched load on top of a slope is developed by the limit analysis using kinematically admissible failure mechanisms. The failure mechanism which is assumed in the analytical solution is verified by three-dimensional strength reduction analyses and laboratory model test. Furthermore, the proposed method and the results are further compared with some published results for illustrating the applicability of the proposed failure mechanism.

  5. Ski skating technique and physiological responses across slopes and speeds.

    Science.gov (United States)

    Kvamme, Bent; Jakobsen, Vidar; Hetland, Svein; Smith, Gerald

    2005-10-01

    Appropriate technique choice may affect ski performance. V2 ski skating technique has in recent years become more widely applied on uphill terrain where V1 technique has typically been used. This investigation compared physiological responses of skiers using V1 and V2 techniques during uphill treadmill roller-skiing. Part 1: six skiers from B-level national ski teams participated in technique comparisons performed under six uphill conditions (3, 4, 5, 6, 7, and 8 degrees) with speeds selected so external work was approximately constant for each slope. The 12 trials of 5-min steady-state skating were randomly distributed across two test sessions of six trials each. Heart rate (HR), oxygen consumption (VO(2)), blood lactate concentration (La) and rating of perceived exertion (RPE) were measured. Part 2: 15 skiers from A-level and B-level national ski teams participated in V1-V2 technique comparison on constant slope (5 degrees) with five speeds ranging from 2.25 to 3.25 m s(-1). In two test sessions of V1 or V2 skating (randomly assigned for 2 days) similar characteristics as Part 1 were measured. Across all variables consistent responses were observed for both the experimental parts. As slope increased, V2 skating became increasingly costly compared to V1 skating. At constant slope across the range of speeds, V2 was more costly than V1 skating. This suggests that it may be disadvantageous for skiers to use V2 instead of V1 skating technique on moderate to steep uphill terrain. Doing so may result in elevated HR, La, and VO(2) compared to V1 skating at the same speed. PMID:16003540

  6. Centrifuge modelling of discrete pile rows to stabilise slopes

    OpenAIRE

    Yoon, Boung Shik

    2008-01-01

    Discrete pile rows are widely used for improving the stability of potentially unstable slopes, where columns of reinforced concrete are constructed in the ground to reinforce it and inhibit instability. The method becomes more cost effective with wider pile spacings, but simultaneously there is also increasing risk that the soil will flow through the gap between adjacent piles, rather than arching across it. The impact of pile spacing along the row, which is likely to have a significant effec...

  7. Aerial Photogrammetric Analysis of a Scree Slope and Cliff

    Science.gov (United States)

    Saunders, Greg; Galland, Olivier; Mair, Karen

    2014-05-01

    Mapping the physical features of landslide tracks provides information about factors controlling landslide movement. The increasing availability of unmanned aerial vehicles (UAV) provides the opportunity to efficiently and cost effectively map terrain. The main goal of this field study is to create a streamlined work-flow from acquisition to interpretation for the photogrammetric analysis of landslide tracks. Here an open source software package MicMac is used for ortho-image and point-cloud creation. A series of two flights were conducted over a scree (rockfall) slope in Kolsas, Norway. The slope runs roughly 500 m north-south with a maximum width of 60 m. A cliff to the west is the source area for the scree. The cliff consists of conglomerate, basalt, and porphyry from bottom to top respectively. The grain size of boulders in the scree slope apparently varies due to lateral differences in the cliff composition. The flights were completed under cloud cover and consisted of multiple lengthwise passes over the scree field. There was a minimum of 75% overlap between images. During the first flight the altitude was roughly 100 m, the camera was positioned normal to the scree (60 degrees from horizontal), and the resolution was 2.7 cm per pixel. The second flight had an altitude of 200 m, the camera orientation was 30 degrees from horizontal, and the resolution was 4.0 cm per pixel. Using the Micmac engine, Ortho-photos and Digital Elevation Models (DEM) were created for both the scree and the cliff. This data will allow for analysis of grain-size, surface roughness, grain-shape, fracture plane orientation, as well as geological mapping. Further work will focus the quantitative assessment of the significance different camera altitudes and angles have on the results. The work-flow used in this study provides a repeatable method for aerial photogrammetric surveys of scree slopes.

  8. Conservation laws for shallow water waves on a sloping beach

    OpenAIRE

    Yilmaz Akyildiz

    1986-01-01

    Shallow water waves are governed by a pair of non-linear partial differential equations. We transfer the associated homogeneous and non-homogeneous systems, (corresponding to constant and sloping depth, respectively), to the hodograph plane where we find all the non-simple wave solutions and construct infinitely many polynomial conservation laws. We also establish correspondence between conservation laws and hodograph solutions as well as Bäcklund transformations by using the linear nature...

  9. Experimental Study on Flow Characteristic in Sloping Weir

    OpenAIRE

    Joongu Joongu Kang; Sungjoong Kim; Hongkoo Yeo; Namjoo Lee

    2014-01-01

    Drop structure is a key hydraulic structure used in river improvement projects for flood control purposes. However, as demand for riparian construction techniques with environmental considerations is increasing both domestically and internationally, discontinuation of aquatic organisms as a result of high head is raised as a serious issue associated with the existing drop structures. Accordingly, it has become necessary to install a drop structure with a mild slope r...

  10. SNOW ACCUMULATION DYNAMICS ON SLOPES AND DITCHES FOR UNSOLVED GROOVE

    OpenAIRE

    N. Yu. Alimova; O. V. Gladysheva; T. V. Samodurova

    2012-01-01

    Statement of the problem. The problems of estimating a residual snow load capacity for unopen grooves and predicting the beginning of snow accumulation on the driveway have been discussed.Results. The mathematical model for the calculation of snow accumulation on slopes and in ditches of grooves is presented which takes into account snowfall accumulations. The balance equation for the calculation of snow accumulations in an unopen groove is suggested. The calculation formula of snow container...

  11. Slope Stability Analysis of Itakpe Iron Ore Mine, Itakpe, Nigeria

    OpenAIRE

    Jide Muili Akande; Chinwuba Arum; Rasheed A. Adebimpe

    2011-01-01

    The slope stability of the Itakpe Iron Ore Mine has been carried out using computer software, ROCKPACK III. One hundred and twenty three dip and dip direction values were obtained using compass clinometer. The Itakpe Iron Ore Mine was divided into four benches; 241 - 258 m, 263 - 275 m, 276 - 286 m and 308 - 312 m. Joints along the discontinuities were mapped. The data obtained were analyzed using ROCKPACK III. The results indicate that the discontinuities within the critical zone are potenti...

  12. AMS radiocarbon dating on Campos Basin, Southeast Brazilian Continental Slope

    International Nuclear Information System (INIS)

    We present results on radiocarbon dating of foraminifera shell samples, collected on the upper slope of Campos Basin, in Southern Brazil. This is the first time that the sedimentation rate of this area is measured with a fine scale (cm) stratigraphy. 14C ages vary from (2560 ± 80) years. BP at the top to (7260 ± 80) years. BP at the bottom of the sediment column. The mean accumulation ratio for the whole column is (6.2 ± 0.7) cm/kyears

  13. Edge capillary-gravity waves on a sloping beach

    Science.gov (United States)

    Muzylev, Sergey V.; Bulgakov, Sergey N.; Duran-Matute, Matias

    2005-04-01

    It is shown how the solution for velocity potential may be determined when the effect of surface tension is included in the linearized theory of Ursell-type edge waves over a plane-sloping beach. The problem is examined without making a hydrostatic assumption. Explicit solutions for edge capillary-gravity waves are given and the dispersion equation is obtained. The influence of capillarity on gravity waves is discussed.

  14. Conservation laws for shallow water waves on a sloping beach

    Science.gov (United States)

    Akyildiz, Yilmaz

    1982-09-01

    Shallow water waves are governed by a pair of nonlinear partial differential equations. We transfer the associated homogeneous and nonhomogeneous systems (corresponding to constant and sloping depth, respectively) to the hodograph plane, where we find all the nonsimple wave solutions and construct infinitely many polynomial conversation laws. We also establish correspondence between conservation laws and hodograph solutions as well as Bäcklund transformations by using the linear nature of the problems on the hodograph plane.

  15. Wood-soil interactions in soil bioengineering slope stabilization works

    OpenAIRE

    Moscatelli MC; Romagnoli M; Cenfi S; Lagomarsino A; Di Tizio A; Spina S; Grego S

    2009-01-01

    In this work we propose the use of soil quality indicators with the aim of assessing the environmental impact of soil bioengineering works. This study was carried out in central Italy where soil bioengineering slope stabilization works were established using chestnut wood. In particular the goal of this study was to determine the occurrence of a wood-effect, that is changes of soil properties due to the presence of decomposing logs in two sites characterized by different time span since works...

  16. Coal database for Cook Inlet and North Slope, Alaska

    Science.gov (United States)

    Stricker, Gary D.; Spear, Brianne D.; Sprowl, Jennifer M.; Dietrich, John D.; McCauley, Michael I.; Kinney, Scott A.

    2011-01-01

    This database is a compilation of published and nonconfidential unpublished coal data from Alaska. Although coal occurs in isolated areas throughout Alaska, this study includes data only from the Cook Inlet and North Slope areas. The data include entries from and interpretations of oil and gas well logs, coal-core geophysical logs (such as density, gamma, and resistivity), seismic shot hole lithology descriptions, measured coal sections, and isolated coal outcrops.

  17. Mixing along continental slopes affects North Atlantic Deep Water

    Science.gov (United States)

    Kumar, Mohi

    2011-08-01

    In the northern Atlantic Ocean, cold salty water from the Arctic Ocean sinks to form North Atlantic Deep Water, a current that hugs the bottom of the ocean as it travels south toward Antarctica. The formation of this water mass is vital to large-scale global ocean circulation and the spread of heat and nutrients across the planet's waters—when deep waters surface, they form warm surface currents such as the Gulf Stream, which are swept by wind back to the North Atlantic, where they cool and sink, beginning the cycle anew. In the Faroe-Shetland Channel, so named because it lies between Scotland's Shetland Islands and Denmark's Faroe Islands, deep water masses that are tributaries to North Atlantic Deep Water abut the steep continental slopes that bracket the channel. The ebb and flow of ocean tides there produce horizontal and vertical waves that travel long distances and may break on the slopes like waves on a beach. These waves, called internal tides, were monitored and modeled by Hall et al., who sought to understand how they affect the mixing of different water masses that pass through the channel. They found that strong mixing due to internal tides on the slopes that bound the Faroe-Shetland Channel may be an important mechanism by which North Atlantic Deep Water acquires the physical and chemical properties that it carries across the globe. (Journal of Geophysical Research-Oceans, doi:10.1029/2010JC006213, 2011)

  18. The slope of the GRB Variability/Peak Luminosity Correlation

    CERN Document Server

    Guidorzi, C; Montanari, E; Rossi, F; Amati, L; Gomboc, A; Mundell, C G

    2006-01-01

    From a sample of 32 GRBs with known redshift (Guidorzi et al. 2005) and then a sample of 551 BATSE GRBs with derived pseudo-redshift (Guidorzi 2005), the time variability/peak luminosity correlation (V vs. L) found by Reichart et al. (2001) was tested. For both samples the correlation is still found but less relevant due to a much higher spread of the data. Assuming a straight line in the logL-logV plane (logL = m logV + b), as done by Reichart et al., the slope was found lower than that derived by Reichart et al.: m = 1.3_{-0.4}^{+0.8} (Guidorzi et al. 2005), m = 0.85 +- 0.02 (Guidorzi 2005), to be compared with m = 3.3^{+1.1}_{-0.9} (Reichart et al. 2001). Reichart & Nysewander (2005) attribute the different slope to the fact we do not take into account in the fit the variance of the sample, and demonstrate that, using the method by Reichart (2001), the data set of Guidorzi et al. (2005) in logL-logV plane is still well described with slope m = 3.4^{+0.9}_{-0.6}. Here we compare the results of two metho...

  19. An Adaptive Slope Compensation Circuit and its Application

    Directory of Open Access Journals (Sweden)

    Chen Guanghua

    2013-01-01

    Full Text Available To resolve over-compensation problem in the current mode PWM switch power, a new adaptive slope compensation circuit is proposed in this study. In the circuit, the difference between the output and input voltage is positive correlative with the duty cycle of switch signal which is used to generate the control signal varying with the duty ratio. The control signal is used to control the gate voltage of MOS operating in linear region which changes the linear drain-source resistance. With clamping circuit, a proportional ramp voltage with controllable slope is produced and amplified for compensation system by two stage amplifier. This compensation voltage is almost ideal which can reduce the negative effect of over-compensation farthest. This circuit is applied to an LED driver IC and simulated in Cadence with CSMC 0.5um BiCMOS library. The results show that the boost driver circuit using adaptive compensation has about 28% dynamic response time reducing compared with the settled slope compensation. Therefore the proposed compensation circuit can improve systems dynamic responsibility effectively.

  20. Review of the Frontier Workshop and Q-slope results

    Energy Technology Data Exchange (ETDEWEB)

    Gianluigi Ciovati

    2005-09-20

    Over the last few years, significant progress has been made to produce field emission free niobium surfaces. Nowadays, the major limitation towards achieving the critical field in radio-frequency (rf) superconducting cavities made of bulk niobium of high purity is represented by the so-called ''high field Q-slope'' or ''Q-drop''. This phenomenon is characterized by a sharp decrease of the cavity quality factor, in absence of field emission, starting at a peak surface magnetic field of the order of 100 mT. It has been observed that these losses are usually reduced by a low-temperature ''in-situ'' baking, typically at 100-120 C for 24-48 h. Several models have been proposed to explain the high field Q-slope and many experiments have been conducted in different laboratories to validate such models. A three-day workshop was held in Argonne in September 2004 to present and discuss experimental and theoretical results on the present limitations of superconducting rf cavities. In this paper, we will focus on the high field Q-slope by reviewing the results presented at the workshop along with other experimental data. In order to explain the Q-drop and the baking effect we will discuss an improved version of the oxygen diffusion model.

  1. Meteorological, elevation, and slope effects on surface hoar formation

    Science.gov (United States)

    Horton, S.; Schirmer, M.; Jamieson, B.

    2015-08-01

    Failure in layers of buried surface hoar crystals (frost) can cause hazardous snow slab avalanches. Surface hoar crystals form on the snow surface and are sensitive to micro-meteorological conditions. In this study, the role of meteorological and terrain factors was investigated for three layers of surface hoar in the Columbia Mountains of Canada. The distribution of crystals over different elevations and aspects was observed on 20 days of field observations during a period of high pressure. The same layers were modelled over simplified terrain on a 2.5 km horizontal grid by forcing the snow cover model SNOWPACK with forecast weather data from a numerical weather prediction model. Modelled surface hoar growth was associated with warm air temperatures, high humidity, cold surface temperatures, and low wind speeds. Surface hoar was most developed in regions and elevation bands where these conditions existed, although strong winds at high elevations caused some model discrepancies. SNOWPACK simulations on virtual slopes systematically predicted smaller surface hoar on south-facing slopes. In the field, a complex combination of surface hoar and sun crusts were observed, suggesting the simplified model did not adequately resolve the surface energy balance on slopes. Overall, a coupled weather-snow cover model could benefit avalanche forecasters by predicting surface hoar layers on a regional scale over different elevation bands.

  2. North Slope Decision Support for Water Resource Planning and Management

    Energy Technology Data Exchange (ETDEWEB)

    Schnabel, William; Brumbelow, Kelly

    2013-03-31

    The objective of this project was to enhance the water resource decision-making process with respect to oil and gas exploration/production activities on Alaska’s North Slope. To this end, a web-based software tool was developed to allow stakeholders to assemble, evaluate, and communicate relevant information between and amongst themselves. The software, termed North Slope Decision Support System (NSDSS), is a visually-referenced database that provides a platform for running complex natural system, planning, and optimization models. The NSDSS design was based upon community input garnered during a series of stakeholder workshops, and the end product software is freely available to all stakeholders via the project website. The tool now resides on servers hosted by the UAF Water and Environmental Research Center, and will remain accessible and free-of-charge for all interested stakeholders. The development of the tool fostered new advances in the area of data evaluation and decision support technologies, and the finished product is envisioned to enhance water resource planning activities on Alaska’s North Slope.

  3. Comparison of slope stability in two Brazilian municipal landfills

    International Nuclear Information System (INIS)

    The implementation of landfill gas to energy (LFGTE) projects has greatly assisted in reducing the greenhouse gases and air pollutants, leading to an improved local air quality and reduced health risks. The majority of cities in developing countries still dispose of their municipal waste in uncontrolled 'open dumps.' Municipal solid waste landfill construction practices and operating procedures in these countries pose a challenge to implementation of LFGTE projects because of concern about damage to the gas collection infrastructure (horizontal headers and vertical wells) caused by minor, relatively shallow slumps and slides within the waste mass. While major slope failures can and have occurred, such failures in most cases have been shown to involve contributory factors or triggers such as high pore pressures, weak foundation soil or failure along weak geosynthetic interfaces. Many researchers who have studied waste mechanics propose that the shear strength of municipal waste is sufficient such that major deep-seated catastrophic failures under most circumstances require such contributory factors. Obviously, evaluation of such potential major failures requires expert analysis by geotechnical specialists with detailed site-specific information regarding foundation soils, interface shearing resistances and pore pressures both within the waste and in clayey barrier layers or foundation soils. The objective of this paper is to evaluate the potential use of very simple stability analyses which can be used to study the potential for slumps and slides within the waste mass and which may represent a significant constraint on construction and development of the landfill, on reclamation and closure and on the feasibility of a LFGTE project. The stability analyses rely on site-specific but simple estimates of the unit weight of waste and the pore pressure conditions and use 'generic' published shear strength envelopes for municipal waste. Application of the slope stability analysis method is presented in a case study of two Brazilian landfill sites; the Cruz das Almas Landfill in Maceio and the Muribeca Landfill in Recife. The Muribeca site has never recorded a slope failure and is much larger and better-maintained when compared to the Maceio site at which numerous minor slumps and slides have been observed. Conventional limit-equilibrium analysis was used to calculate factors of safety for stability of the landfill side slopes. Results indicate that the Muribeca site is more stable with computed factors of safety values in the range 1.6-2.4 compared with computed values ranging from 0.9 to 1.4 for the Maceio site at which slope failures have been known to occur. The results suggest that this approach may be useful as a screening-level tool when considering the feasibility of implementing LFGTE projects

  4. Agricultural terraces and slope instability at Cinque Terre (NW Italy)

    Science.gov (United States)

    Brandolini, Pierluigi; Cevasco, Andrea

    2015-04-01

    Cinque Terre, located in the eastern Liguria, are one of the most representative examples of terraced coastal landscape within the Mediterranean region. They are the result of a century-old agricultural practice and constitute an outstanding example of human integration with the natural landscape. For this highly unusual man-made coastal landscape, the Cinque Terre have been recognized as a World Heritage Site by UNESCO since 1997 and became National Park in 1999. The complex network of retaining dry stone walls and drainage networks ensured through times the control of shallow water erosion and therefore, indirectly, favoured debris cover stability. The lack of maintenance of terracing due to farmer abandonment since the 1950s led to widespread slope erosion phenomena. The effects of such phenomena culminated during the 25 October 2011 storm rainfall event, when slope debris materials charged by streams gave rise to debris floods affecting both Monterosso and Vernazza villages. As the analysis of the relationships between geo-hydrological processes and land use in the Vernazza catchment highlighted, abandoned and not well maintained terraces were the most susceptible areas to shallow landsliding and erosion triggered by intense rainfall. As a consequence, the thousands of kilometres of dry stone walls retaining millions of cubic metres of debris cover at Cinque Terre currently constitute a potential menace for both villages, that are mainly located at the floor of deep cut valleys, and tourists. Given the increasing human pressure due to tourist activities, geo-hydrological risk mitigation measures are urgently needed. At the same time, restoration policies are necessary to preserve this extraordinary example of terraced coastal landscape. In this framework, the detailed knowledge of the response of terraced areas to intense rainfall in terms of slope instability is a topic issue in order to identify adequate land planning strategies as well as the areas where interventions should be focused primarily. In this study, with the aim to contribute to a better understanding of geo-hydrological hazards at basin scale, the main types of slope instability phenomena that occurred on agricultural terraces at Cinque Terre following the 25 October 2011 rainfall event are presented in relation to different geological and geomorphological conditions. In particular, selected examples of shallow landslides and erosive slope processes due to running water affecting abandoned or cultivated terraces for vineyards and olive grooves will be shown.

  5. Comparison of slope stability in two Brazilian municipal landfills.

    Science.gov (United States)

    Gharabaghi, B; Singh, M K; Inkratas, C; Fleming, I R; McBean, E

    2008-01-01

    The implementation of landfill gas to energy (LFGTE) projects has greatly assisted in reducing the greenhouse gases and air pollutants, leading to an improved local air quality and reduced health risks. The majority of cities in developing countries still dispose of their municipal waste in uncontrolled 'open dumps.' Municipal solid waste landfill construction practices and operating procedures in these countries pose a challenge to implementation of LFGTE projects because of concern about damage to the gas collection infrastructure (horizontal headers and vertical wells) caused by minor, relatively shallow slumps and slides within the waste mass. While major slope failures can and have occurred, such failures in most cases have been shown to involve contributory factors or triggers such as high pore pressures, weak foundation soil or failure along weak geosynthetic interfaces. Many researchers who have studied waste mechanics propose that the shear strength of municipal waste is sufficient such that major deep-seated catastrophic failures under most circumstances require such contributory factors. Obviously, evaluation of such potential major failures requires expert analysis by geotechnical specialists with detailed site-specific information regarding foundation soils, interface shearing resistances and pore pressures both within the waste and in clayey barrier layers or foundation soils. The objective of this paper is to evaluate the potential use of very simple stability analyses which can be used to study the potential for slumps and slides within the waste mass and which may represent a significant constraint on construction and development of the landfill, on reclamation and closure and on the feasibility of a LFGTE project. The stability analyses rely on site-specific but simple estimates of the unit weight of waste and the pore pressure conditions and use "generic" published shear strength envelopes for municipal waste. Application of the slope stability analysis method is presented in a case study of two Brazilian landfill sites; the Cruz das Almas Landfill in Maceio and the Muribeca Landfill in Recife. The Muribeca site has never recorded a slope failure and is much larger and better-maintained when compared to the Maceio site at which numerous minor slumps and slides have been observed. Conventional limit-equilibrium analysis was used to calculate factors of safety for stability of the landfill side slopes. Results indicate that the Muribeca site is more stable with computed factors of safety values in the range 1.6-2.4 compared with computed values ranging from 0.9 to 1.4 for the Maceio site at which slope failures have been known to occur. The results suggest that this approach may be useful as a screening-level tool when considering the feasibility of implementing LFGTE projects. PMID:17897819

  6. The runup on a multilinear sloping beach model

    Science.gov (United States)

    Fuentes, Mauricio A.; Ruiz, Javier A.; Riquelme, Sebastián

    2015-05-01

    A general method of solution for the runup evolution and some analytical results concerning a more general bathymetry than a canonical sloping beach model are presented. We studied theoretically the water wave elevation and runup generated on a continuous piecewise linear bathymetry, by solving analytically the linear shallow water wave equations in the 1+1 dimensional case. Non-horizontal linear segments are assumed and we develop an specific matrix propagator scheme, similar to the ones used in the propagation of elastic seismic wave fields in layered media, to obtain an exact integral form for the runup. A general closed expression for the maximum runup was computed analytically via the Cauchy's residue Theorem for an incident solitary wave and isosceles leading-depression N wave in the case of n + 1 linear segments. It is already known that maximum run-up strongly depends only on the closest slope to the shore, although this has not been mathematically demonstrated yet for arbitraries bathymetries. Analytical and numerical verifications were done to check the validity of the asymptotic maximum runup and we provided the mathematical and bathymetrical conditions that must be satisfied by the model to obtain correct asymptotic solutions. We applied our model to study the runup evolution on a more realistic bathymetry than a canonical sloping beach model. The seabed in a Chilean subduction zone was approximated-from the trench to the shore-by two linear segments adjusting the continental slope and shelf. Assuming an incident solitary wave, the two linear segment bathymetry generates a larger runup than the simple sloping beach model. We also discussed about the differences in the runup evolution computed numerically from incident leading-depression and leading-elevation isosceles N waves. In the latter case, the water elevation at the shore shows a symmetrical behaviour in terms of theirs waveforms. Finally, we applied our solution to study the resonance effects due to the bathymetry modelled by linear segments, which is in agreement with published studies and numerical tests.

  7. Landslides induced by heavy rainfall in July 2012 in Northern Kyushu District, Japan and the influence of long term rainfall increase comparing with the slope destabilization due to strong seismic shaking

    Science.gov (United States)

    Kubota, Tetsuya; Shinohara, Yoshinori; Aditian, Aril

    2013-04-01

    1. Objective We had a deluge in July 2012 in the northern Kyushu district with intense rainfall of 800mm and 108mm/hr. This intensity yielded countless traces of debris flow and landslides, slope failures that induced tremendous damage and causalities in the area. Hence, several field investigations and reconnaissance tasks were conducted to delve into this sediment-related disaster. The various results and the information obtained through this investigation were reported, mentioning the damage, the meteorological condition, geologic-geomorphologic features and hydraulic characteristics of the debris flows, vegetation effects, and the influence of the climate change. Increase in rainfall that may be induced by the global climate change is obvious in Kyushu district, Japan, according to the analysis of rain data observed in various locations including mountainside points that are not influenced by local warming due to urbanization. On this point of view, we are intrigued to elucidate the response of landslide to this increase in rainfall. Hence, its long term impact on this landslide disaster is also analyzed comparing with the slope destabilization due to strong seismic shaking. 2. Method and target areas Field investigation on landslides slopes, slope failures and torrents where debris flows occurred are conducted to obtain the geologic data, geo-structure, vegetation feature, soil samples and topographic data i.e. cross sections, then soil shear tests and soil permeability tests are also conducted. The rainfall data at the nearest rain observatory were obtained from the database of Japan meteorological agency. The long term impact on the slope stability at some slopes in the area is analyzed by the finite element method (FEM) combined with rain infiltration and seepage analysis with the long term rainfall fluctuation data, obtaining factor of safety ( Fs) on real landslide slopes. The results are compared with the destabilized influence on the slopes due to the soil strength reduction by seismic shaking. The target areas are located in northern Kyushu district, western Japan where they often have severe landslide disasters. The geology in research areas consists of Paleozoic and Mesozoic rocks (mainly schist, slate) and Quaternary volcanic sediment such as Aso volcano body. The vegetation consists of mainly Japanese cypress, cedar or bamboo. 3. Result and consideration Consequently, the long term rainfall increase in the region such as increment of approximately 20 mm/hr for rain intensity Ri in 36 years is confirmed statistically using Kendall's rank correlation, and it is found that its impact on slope stability is considerable and critical in other cases. In the sample landslide slopes, even the increase in rain of duration for only 10 years has impact to a certain extent on their stabilities in terms of Fs. The Fs calculated with rains in previous decade is higher than 1.0 that corresponds to stable state, whereas the Fs with present rains is lower than 1.0 such as 0.99 which means unstable state. Extremely heavy rainfall with this impact is generally cause extreme ground water pressure in the slope. It is also obvious that the extreme ground water content rendered even small landslides liquefied to be source of destructive debris flows. In this disaster, especially in the Aso volcanic region, tremendous number of debris flow occurred and even the talus cone slopes which are usually stable collapsed to flow down. However, the influence of the long term rainfall increase on the slopes (such as 1% decrease in Fs) is not relatively small compared with the destabilization of the slopes due to the reduction of soil strength by seismic shaking (8~9 % reduction in Fs after seismic shaking of even 490gal). 4. Conclusion In the disaster in July 2012, many landslides and debris flows originated from landslides induced by concentrated underground water supplied by the heavy rainfall occurred. The increase of rainfall due to climate change with the increasing rate such as 20 mm/hr surely has impact on almost landslide slopes i

  8. Natural dam failure in the eastern slope of the Central Andes of Argentina. Numerical modelling of the 2005 Santa Cruz river outburst flood

    Science.gov (United States)

    Penna, I.; Daicz, S.; Zlotnik, S.; Derron, M.-H.; Jaboyedoff, M.

    2012-04-01

    In the Central Andes of Argentina, ephemeral river blockage due to landslides deposition are common phenomena. During the first fortnight of January 2005, 11.5 * 106m3 of rock collapsed from the east slope of the Santa Cruz valley (San Juan province, Argentina). The rock mass displaced from 4300 m a.s.l., down to the valley bottom, at 2900 m a.s.l., and ran up the opposite flank of the valley. This produced the blockage of the Santa Cruz river and generated the Los Erizos lake. The rapid snow melting during the spring season caused the increase of the water level of the reservoir, leading to a process of overtopping on November 12th of 2005. 30 * 106m3 of water were released from the reservoir and the consequent outburst flood displaced along 250 km. From local reports of arrival times, we estimated that the outburst flood reduced its velocity from around 40 km/h near the source area to 6 km/h in its distal section. A road, bridges, and a mining post where destroyed. 75 tourists had to be rescued from the mountains using helicopters, and people from two localities had to be evacuated. Near its distal part, the flood damaged the facilities of the Caracoles power dam, which was under construction, and its inauguration had to be delayed one year due to the damage. The outburst flood produced changes in the morphology of the valley floor along almost all its path (erosion of alluvial fans, talus and terraces, and deposition of boulders). The most significant changes occurred in the first 70 km, especially upstream narrow sections, showing the importance of the backwater effects due to hydraulic ponding. In this work we carried out numerical simulations to obtain the velocity patterns of the flood, and compared them with those obtained from local reports. Furthermore, we analyze the relationship between the dynamics of the flood with the patterns of erosion and deposition near the source area.

  9. Soil roughness, slope and surface storage relationship for impervious areas

    Science.gov (United States)

    Borselli, Lorenzo; Torri, Dino

    2010-11-01

    SummaryThe study of the relationships between surface roughness, local slope gradient and maximum volume of water storage in surface depressions is a fundamental element in the development of hydrological models to be used in soil and water conservation strategies. Good estimates of the maximum volume of water storage are important for runoff assessment during rainfall events. Some attempts to link surface storage to parameters such as indices of surface roughness and, more rarely, local gradient have been proposed by several authors with empirical equations often conflicting between them and usually based on a narrow range of slope gradients. This suggests care in selecting any of the proposed equations or models and invites one to verify the existence of more realistic experimental relationships, based on physical models of the surfaces and valid for a larger range of gradients. The aim of this study is to develop such a relation for predicting/estimating the maximum volume of water that a soil surface, with given roughness characteristics and local slope gradient, can store. Experimental work has been carried out in order to reproduce reliable rough surfaces able to maintain the following properties during the experimental activity: (a) impervious surface to avoid biased storage determination; (b) stable, un-erodible surfaces to avoid changes of retention volume during tests; (c) absence of hydrophobic behaviour. To meet the conditions a-c we generate physical surfaces with various roughness magnitude using plasticine (emulsion of non-expansible clay and oil). The plasticine surface, reproducing surfaces of arable soils, was then wetted and dirtied with a very fine timber sawdust. This reduced the natural hydrophobic behaviour of the plasticine to an undetectable value. Storage experiments were conducted with plasticine rough surfaces on top of large rigid polystyrene plates inclined at different slope gradient: 2%, 5%, 10%, 20%, 30%. Roughness data collected on the generated plasticine surfaces were successfully compared with roughness data collected on real soil surfaces for similar conditions. A set of roughness indices was computed for each surface using roughness profiles measured with a laser profile meter. Roughness indices included quantiles of the Abbot-Firestone curve, which is used in surface metrology for industrial application to characterize surface roughness in a non-parametric approach ( Whitehouse, 1994). Storage data were fitted with an empirical equation (double negative exponential of roughness and slope). Several roughness indices resulted well related to storage. The better results were obtained using the Abbot-Firestone curve parameter P100. Beside this storage empirical model (SEM) a geometrical model was also developed, trying to give a more physical basis to the result obtained so far. Depression geometry was approximated with spherical cups. A general physical model was derived (storage cup model - SCM). The cup approximation identifies where roughness elevation comes in and how it relates to slope gradient in defining depression volume. Moreover, the exponential decay used for assessing slope effect on storage volume in the empirical model of Eqs. (8) and (9) emerges as consistent with distribution of cup sizes.

  10. The Socioeconomic Assessment of Sloping Land Conversion Program in China

    DEFF Research Database (Denmark)

    Liu, Zhen

    2014-01-01

    Abstract This thesis mainly focuses on the socioeconomic impact of the largest Ecological Recovery Program ? the Sloping Land Conversion Program (SLCP), also called Grain for Green Program (GFG) in China. The central government initiated this program in 1999 and it was launched nationwide in 2002 with the aim to combat deforestation, ecological degradation, over cultivation of sloping land and soil erosion. However, we also believe it brings changes to the rural economic structure and household livelihood strategy. Applying and developing some empirical and theoretical methods with a large amount of household survey data, this study aims to improve our understanding of the treatment effect of the SLCP on farm households, which is split into three parts. The first paper ? The Sloping Land Conversion Program in China: Effects on Rural Households’ Livelihood Diversification, evaluates the effects of the implementation of the Sloping Land Conversion Program (SLCP) on livelihood diversification, which is thought to be the solution to poverty and environmental dilemmas. Our results show that SLCP works as a valid external policy intervention on rural livelihood diversification. In addition, the findings suggest that there exist heterogeneous effects of SLCP implementation on livelihood diversification across different rural income groups. The lower income group was more affected by the program in terms of income diversification. The Second paper ? The Effects of Sloping Land Conversion Program on Agricultural Households, analyzes whether the program influences farm household behaviour in the form of production, consumption and labor supply. In doing so, we first develop a microeconomic Agricultural Household Model (AHM), which can model the production, consumption, and labor supply decisions of farm households in rural China in a theoretically consistent fashion. Based on this theoretical model, we derive an empirical specification for econometrically estimating the effects of the SLCP and other exogenous factors. Using a large longitudinal farm household survey data set, we estimate the empirical model with the Hausman-Taylor Estimator method. The key results regarding the households’ responses to the program nicely coincide with the results of our theoretical comparative static analysis, i.e. the SLCP decreases agricultural production and increases non-farm labor supply and consumption. In addition, on average, reduction of compensation payment rate lowers the treatment effect of the SLCP on participating households from both River basins. Lastly, the third paper, ? The effect of the Sloping Land Conversion Program on farm household productivity in rural China, investigates the treatment effect (the causal effect) of the Sloping Land Conversion Program (SLCP) on farm household productivity. Using the same survey data set as the above two papers, I apply the nonparametric Malmquist index method to estimate the change in farm household productivity. In connection with evaluating the treatment effects, propensity score matching, which can give a randomized evaluation, is employed in a second stage. The main results show that the SLCP significantly improved the productivity of participants in the first funding period which are mostly from efficiency improvements, while the effects decreased in the second round except the positive impact in 2007. Moreover, it is found that there are heterogeneous effects on farm household productivity between the south and north, as well as poor and rich region. In sum, the findings from this thesis highlight that SLCP has significant effects on the farm household in different ways, most of which support the policy intention of central government according to our own understanding, whereas the effects differ depending on the group, region and period. This research provides a detailed understanding of the treatment effects of the SLCP and thus, contributes to the on-going political debate about the revision of the SLCP and also to the scientific knowledge about the effect evaluation of

  11. 75 FR 17433 - Notice of Public Meeting, North Slope Science Initiative-Science Technical Advisory Panel

    Science.gov (United States)

    2010-04-06

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal meeting...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  12. 76 FR 79211 - Notice of Public Meeting, North Slope Science Initiative-Science Technical Advisory Panel

    Science.gov (United States)

    2011-12-21

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal meeting...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  13. 76 FR 55943 - Notice of Public Meeting, North Slope Science Initiative-Science Technical Advisory Panel

    Science.gov (United States)

    2011-09-09

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal meeting...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  14. 75 FR 52370 - Notice of Public Meeting, North Slope Science Initiative-Science Technical Advisory Panel

    Science.gov (United States)

    2010-08-25

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal NSSI...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  15. 76 FR 10388 - Notice of Public Meeting, North Slope Science Initiative-Science Technical Advisory Panel

    Science.gov (United States)

    2011-02-24

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal meeting...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  16. 78 FR 59714 - Notice of Public Meeting, North Slope Science Initiative-Science Technical Advisory Panel

    Science.gov (United States)

    2013-09-27

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal meeting...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  17. 75 FR 79017 - Notice of Public Meeting, North Slope Science Initiative-Science Technical Advisory Panel

    Science.gov (United States)

    2010-12-17

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal meeting...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  18. 77 FR 21806 - Notice of Public Meeting, North Slope Science Initiative-Science Technical Advisory Panel

    Science.gov (United States)

    2012-04-11

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal meeting...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  19. 77 FR 46769 - Notice of Public Meeting, North Slope Science Initiative-Science Technical Advisory Panel

    Science.gov (United States)

    2012-08-06

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal meeting...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  20. 78 FR 4870 - Notice of Public Meeting, North Slope Science Initiative-Science Technical Advisory Panel

    Science.gov (United States)

    2013-01-23

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal meeting...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  1. 75 FR 159 - Notice of Public Meeting, North Slope Science Initiative, Science Technical Advisory Panel, Alaska

    Science.gov (United States)

    2010-01-04

    ...present written comments to the Science Technical Advisory Panel through...Executive Director, North Slope Science Initiative. Each formal meeting...special assistance, such as sign language interpretation, transportation...Executive Director, North Slope Science Initiative. Before...

  2. "Taevaredel" sündis Billite talus / Meeli Müüripeal

    Index Scriptorium Estoniae

    Müüripeal, Meeli, 1963-

    2006-01-01

    Billite talust, kus läti kirjanik ja luuletaja Edvards Virza (1883-1940) kirjutas romaani "Taevaredel" ("Straumeni"). Tõlk, kirjanik ja diplomaat Anna Zhigure oma vanaisa E. Virza kirjutatud romaani tähendusest lätlastele ja Billite talust, kus praegu elab A. Zhigure vend. 4 värv. ill

  3. Halocline water modification and along slope advection at the Laptev Sea continental margin

    OpenAIRE

    Bauch, D; Torres-Valdes, S.; Polyakov, I; Novikhin, A.; I. Dmitrenko; Mckay, J; Mix, A.

    2013-01-01

    A general pattern in water mass distribution and potential shelf-basin exchanges is revealed at the Laptev Sea continental slope based on hydrochemical and stable oxygen isotope data from summers 2005–2009. Despite considerable interannual variations, a frontal system can be inferred between shelf, continental slope and central Eurasian Basin waters in the upper 100 m of the water column along the continental slope. Net sea-ice melt is consistently found at the continental slope; however the ...

  4. The Contribution of Particle Swarm Optimization to Three-Dimensional Slope Stability Analysis

    OpenAIRE

    Roohollah Kalatehjari; Ahmad Safuan A Rashid; Nazri Ali; Mohsen Hajihassani

    2014-01-01

    Over the last few years, particle swarm optimization (PSO) has been extensively applied in various geotechnical engineering including slope stability analysis. However, this contribution was limited to two-dimensional (2D) slope stability analysis. This paper applied PSO in three-dimensional (3D) slope stability problem to determine the critical slip surface (CSS) of soil slopes. A detailed description of adopted PSO was presented to provide a good basis for more contribution of this techniqu...

  5. Methodology to evaluate rock slope stability under seismic conditions at Solà de Santa Coloma, Andorra

    OpenAIRE

    O. Mavrouli; J. Corominas; J. Wartman

    2009-01-01

    An analytical methodology is presented to evaluate rock slope stability under seismic conditions by considering the geomechanical and topographic properties of a slope. The objective is to locate potential rockfall source areas and evaluate their susceptibility in terms of probability of failure. For this purpose, the slope face of a study area is discretized into cells having homogenous aspect, slope angle, rock properties and joint set orientations. A pseudostatic limit equilibrium analysis...

  6. Protection Roles of Tea-Citrus Garden on Slopes (N Iran)

    OpenAIRE

    Ghassem Habibi Bibalani; Lila Joodi; Naeimeh Shibaei; Zia Bazhrang

    2007-01-01

    This study investigates the effects of vegetation on the stability of slopes using the finite element method. Parametric studies were performed to assess the sensitivity of the stability of a slope to the variation in the key vegetation and soil parameters. Results show that vegetation plays an important role in stabilizing shallow-seated failure of slopes and significantly affects stability. As Iran has a long history of landslides, this research deals with the effect of scrubs on slope stab...

  7. Evaluation of Slope Assessment System in Predicting Landslides along Roads Underlain by Granitic Formation

    OpenAIRE

    Huat, Bujang B. K.; S. Jamaludin

    2005-01-01

    A slope assessment is to estimate the probability of occurrence and likely severity of landslides in a given area. This study evaluates two existing Slope Assessment Systems (SAS) for predicting landslide at the micro level of assessment developed by the Public Works Department of Malaysia, namely the Slope Information Management System (SIMS) and the Slope Management and Risk Tracking System (SMART). From the results of this study, it appears that none of the existing SAS is satisfactory for...

  8. Associations between Verbal Learning Slope and Neuroimaging Markers across the Cognitive Aging Spectrum

    Science.gov (United States)

    Gifford, Katherine A.; Phillips, Jeffrey S.; Samuels, Lauren R.; Lane, Elizabeth M.; Bell, Susan P.; Liu, Dandan; Hohman, Timothy J.; Romano, Raymond R.; Fritzsche, Laura R.; Lu, Zengqi; Jefferson, Angela L.

    2015-01-01

    A symptom of mild cognitive impairment (MCI) and Alzheimer's disease (AD) is a flat learning profile. Learning slope calculation methods vary, and the optimal method for capturing neuroanatomical changes associated with MCI and early AD pathology is unclear. This study cross-sectionally compared four different learning slope measures from the Rey Auditory Verbal Learning Test (simple slope, regression-based slope, two-slope method, peak slope) to structural neuroimaging markers of early AD neurodegeneration (hippocampal volume, cortical thickness in parahippocampal gyrus, precuneus, and lateral prefrontal cortex) across the cognitive aging spectrum [normal control (NC); (n = 198; age = 76 ± 5), MCI (n = 370; age = 75 ± 7), and AD (n = 171; age = 76 ± 7)] in ADNI. Within diagnostic group, general linear models related slope methods individually to neuroimaging variables, adjusting for age, sex, education, and APOE4 status. Among MCI, better learning performance on simple slope, regression-based slope, and late slope (Trial 2–5) from the two-slope method related to larger parahippocampal thickness (all p-values < .01) and hippocampal volume (p < .01). Better regression-based slope (p < .01) and late slope (p < .01) were related to larger ventrolateral prefrontal cortex in MCI. No significant associations emerged between any slope and neuroimaging variables for NC (p-values ? .05) or AD (p-values ? .02). Better learning performances related to larger medial temporal lobe (i.e., hippocampal volume, parahippocampal gyrus thickness) and ventrolateral prefrontal cortex in MCI only. Regression-based and late slope were most highly correlated with neuroimaging markers and explained more variance above and beyond other common memory indices, such as total learning. Simple slope may offer an acceptable alternative given its ease of calculation. PMID:26219209

  9. Stability of slopes in residual soils Estabilidad de taludes en suelos residuales

    OpenAIRE

    Laurence Wesley

    2011-01-01

    This paper examines and discusses a number of factors that make slope stability assessments, and slope engineering in residual soils somewhat different from sedimentary soils. In particular, slopes are generally steeper and of higher permeability. They are also likely to be more heterogeneous and thus less amenable to analytical assessment than slopes in sedimentary soils. These factors are discussed in some detail. It is explained that climate and weather influence is much greater in residua...

  10. Adaptive glide slope control for parafoil and payload aircraft

    Science.gov (United States)

    Ward, Michael

    Airdrop systems provide a unique capability of delivering large payloads to undeveloped and inaccessible locations. Traditionally, these systems have been unguided, requiring large landing zones and drops from low altitude. The invention of the steerable, gliding, ram-air parafoil enabled the possibility of precision aerial payload delivery. In practice, the gliding ability of the ram-air parafoil can actually create major problems for airdrop systems by making them more susceptible to winds and allowing them to achieve far greater miss distances than were previously possible. Research and development work on guided airdrop systems has focused primarily on evolutionary improvements to the guidance algorithm, while the navigation and control algorithms have changed little since the initial autnomous systems were developed. Furthermore, the control mechanisms have not changed since the invention of the ram-air canopy in the 1960’s. The primary contributions of this dissertation are: (1) the development of a reliable and robust method to identify a flight dynamic model for a parafoil and payload aircraft using minimal sensor data; (2) the first demonstration in flight test of the ability to achieve large changes in glide slope over ground using coupled incidence angle variation and trailing edge brake deflection; (3) the first development of a control law to implement glide slope control on an autonomous system; (4) the first flight tests of autonomous landing with a glide slope control mechanism demonstrating an improvement in landing accuracy by a factor of 2 or more in especially windy conditions, and (5) the first demonstrations in both simulation and flight test of the ability to perform in-flight system identification to adapt the internal control mappings to flight data and provide dramatic improvements in landing accuracy when there is a significant discrepancy between the assumed and actual flight characteristics.

  11. Slopes To Prevent Trapping of Bubbles in Microfluidic Channels

    Science.gov (United States)

    Greer, Harold E.; Lee, Michael C.; Smith, J. Anthony; Willis, Peter A.

    2010-01-01

    The idea of designing a microfluidic channel to slope upward along the direction of flow of the liquid in the channel has been conceived to help prevent trapping of gas bubbles in the channel. In the original application that gave rise to this idea, the microfluidic channels are parts of micro-capillary electrophoresis (microCE) devices undergoing development for use on Mars in detecting compounds indicative of life. It is necessary to prevent trapping of gas bubbles in these devices because uninterrupted liquid pathways are essential for sustaining the electrical conduction and flows that are essential for CE. The idea is also applicable to microfluidic devices that may be developed for similar terrestrial microCE biotechnological applications or other terrestrial applications in which trapping of bubbles in microfluidic channels cannot be tolerated. A typical microCE device in the original application includes, among other things, multiple layers of borosilicate float glass wafers. Microfluidic channels are formed in the wafers, typically by use of wet chemical etching. The figure presents a simplified cross section of part of such a device in which the CE channel is formed in the lowermost wafer (denoted the channel wafer) and, according to the present innovation, slopes upward into a via hole in another wafer (denoted the manifold wafer) lying immediately above the channel wafer. Another feature of the present innovation is that the via hole in the manifold wafer is made to taper to a wider opening at the top to further reduce the tendency to trap bubbles. At the time of reporting the information for this article, an effort to identify an optimum technique for forming the slope and the taper was in progress. Of the techniques considered thus far, the one considered to be most promising is precision milling by use of femtosecond laser pulses. Other similar techniques that may work equally well are precision milling using a focused ion beam, or a small diamond-tipped drill bit.

  12. Stability analysis of jointed rock slope by the block theory

    International Nuclear Information System (INIS)

    The block theory to analyze three dimensional stability problems of discontinuous rock masses is applied to the actual discontinuous rock slope. Taking into consideration that the geometrical information about discontinuities generally increases according to progressive steps of rock investigation in field, the method adopted for analysis is divided into following two steps; 1) the statistical/probabilitical analysis using information from the primary investigation stage which mainly consists of that of natural rock outcrops, and 2) the deterministic analysis correspond to the secondary stage using exploration adits. (author)

  13. Monte-Carlo Modeling of Some Niger Delta Slope Events

    OpenAIRE

    M.I. Oladapo; J.S Ojo; M. O. Olorunfemi; B.A. Adetola

    2009-01-01

    Monte-Carlo modeling has been utilized in this study to simulate seismic P-wave events on four horizons (AA, BB, CC and DD) in a Niger Delta Slope environment with the aim of generating AVO attributes. Monte-Carlo modeling undertaken on a well log from the Gulf of Mexico served as a generic model and control. Trends analysis regressions generated in the environment served as input for the models while default parameter in SAVIOR (fluid method) was used for establishing reservoir fluid p...

  14. Conservation laws for shallow water waves on a sloping beach

    Directory of Open Access Journals (Sweden)

    Yilmaz Akyildiz

    1986-06-01

    Full Text Available Shallow water waves are governed by a pair of non-linear partial differential equations. We transfer the associated homogeneous and non-homogeneous systems, (corresponding to constant and sloping depth, respectively, to the hodograph plane where we find all the non-simple wave solutions and construct infinitely many polynomial conservation laws. We also establish correspondence between conservation laws and hodograph solutions as well as Bäcklund transformations by using the linear nature of the problems on the hodogrpah plane.

  15. Universality in self-organized critical slope models

    CERN Document Server

    Vazquez, A; Vazquez, Alexei; Sotolongo-Costa, Oscar

    1999-01-01

    The dynamics of critical slope self-organized critical models is studied, using a previous mapping into a linear interface depinning model dragged at one end. The model is solved obtaining the complete set of scaling exponents. Some results are supported by previous RG developed for constant force linear interface depinning models but others, like the linear dependency of the susceptibility with system size, are intrinsic of this model which belongs to a different universality class. The comparison of our results with numerical simulations of ricepile and vortexpile models reported in the literature reveals that, as in the constant force case, there are two universality classes corresponding to random and periodic pinning.

  16. Slippery slopes in flat countries--a response.

    OpenAIRE

    van Delden, J J

    1999-01-01

    In response to the paper by Keown and Jochemsen in which the latest empirical data concerning euthanasia and other end-of-life decisions in the Netherlands is discussed, this paper discusses three points. The use of euthanasia in cases in which palliative care was a viable alternative may be taken as proof of a slippery slope. However, it could also be interpreted as an indication of a shift towards more autonomy-based end-of-life decisions. The cases of non-voluntary euthanasia are a serious...

  17. Cooperative Three-Robot System for Traversing Steep Slopes

    Science.gov (United States)

    Stroupe, Ashley; Huntsberger, Terrance; Aghazarian, Hrand; Younse, Paulo; Garrett, Michael

    2009-01-01

    Teamed Robots for Exploration and Science in Steep Areas (TRESSA) is a system of three autonomous mobile robots that cooperate with each other to enable scientific exploration of steep terrain (slope angles up to 90 ). Originally intended for use in exploring steep slopes on Mars that are not accessible to lone wheeled robots (Mars Exploration Rovers), TRESSA and systems like TRESSA could also be used on Earth for performing rescues on steep slopes and for exploring steep slopes that are too remote or too dangerous to be explored by humans. TRESSA is modeled on safe human climbing of steep slopes, two key features of which are teamwork and safety tethers. Two of the autonomous robots, denoted Anchorbots, remain at the top of a slope; the third robot, denoted the Cliffbot, traverses the slope. The Cliffbot drives over the cliff edge supported by tethers, which are payed out from the Anchorbots (see figure). The Anchorbots autonomously control the tension in the tethers to counter the gravitational force on the Cliffbot. The tethers are payed out and reeled in as needed, keeping the body of the Cliffbot oriented approximately parallel to the local terrain surface and preventing wheel slip by controlling the speed of descent or ascent, thereby enabling the Cliffbot to drive freely up, down, or across the slope. Due to the interactive nature of the three-robot system, the robots must be very tightly coupled. To provide for this tight coupling, the TRESSA software architecture is built on a combination of (1) the multi-robot layered behavior-coordination architecture reported in "An Architecture for Controlling Multiple Robots" (NPO-30345), NASA Tech Briefs, Vol. 28, No. 10 (October 2004), page 65, and (2) the real-time control architecture reported in "Robot Electronics Architecture" (NPO-41784), NASA Tech Briefs, Vol. 32, No. 1 (January 2008), page 28. The combination architecture makes it possible to keep the three robots synchronized and coordinated, to use data from all three robots for decision- making at each step, and to control the physical connections among the robots. In addition, TRESSA (as in prior systems that have utilized this architecture) , incorporates a capability for deterministic response to unanticipated situations from yet another architecture reported in Control Architecture for Robotic Agent Command and Sensing (NPO-43635), NASA Tech Briefs, Vol. 32, No. 10 (October 2008), page 40. Tether tension control is a major consideration in the design and operation of TRESSA. Tension is measured by force sensors connected to each tether at the Cliffbot. The direction of the tension (both azimuth and elevation) is also measured. The tension controller combines a controller to counter gravitational force and an optional velocity controller that anticipates the motion of the Cliffbot. The gravity controller estimates the slope angle from the inclination of the tethers. This angle and the weight of the Cliffbot determine the total tension needed to counteract the weight of the Cliffbot. The total needed tension is broken into components for each Anchorbot. The difference between this needed tension and the tension measured at the Cliffbot constitutes an error signal that is provided to the gravity controller. The velocity controller computes the tether speed needed to produce the desired motion of the Cliffbot. Another major consideration in the design and operation of TRESSA is detection of faults. Each robot in the TRESSA system monitors its own performance and the performance of its teammates in order to detect any system faults and prevent unsafe conditions. At startup, communication links are tested and if any robot is not communicating, the system refuses to execute any motion commands. Prior to motion, the Anchorbots attempt to set tensions in the tethers at optimal levels for counteracting the weight of the Cliffbot; if either Anchorbot fails to reach its optimal tension level within a specified time, it sends message to the other robots and the commanded motion is not executed. If any mechanical error (e.g., stalling of a motor) is detected, the affected robot sends a message triggering stoppage of the current motion. Lastly, messages are passed among the robots at each time step (10 Hz) to share sensor information during operations. If messages from any robot cease for more than an allowable time interval, the other robots detect the communication loss and initiate stoppage.

  18. The upward slope: a study of psychoanalytic transformations.

    Science.gov (United States)

    Freedman, Norbert; Lasky, Richard; Ward, Rhonda

    2009-01-01

    In an examination of twelve audiotaped psychoanalytic sessions, the authors, using both quantitative and qualitative methods, observed a stepwise progression in mental organization, which they term the upward slope. Its constituents include a phase of regression (desymbolization and the agony of equivalence), a phase of transition (disruptive enactment leading to transitional space), and a phase of reorganization (triangulation leading to symbolic synthesis). The hypothesis of a phase-specific progression is advanced, wherein different forms of mental functioning evoke distinct dynamic processes of psychic repair The authors present detailed clinical summaries of the sessions they examined, as well as their own observational comments, to illustrate these ideas. PMID:19334650

  19. Ratio of slopes method for quantitative analysis in ceramic bodies

    International Nuclear Information System (INIS)

    A quantitative x-ray diffraction analysis technique developed at University of Sheffield was adopted, rather than the previously widely used internal standard method, to determine the amount of the phases present in a reformulated whiteware porcelain and a BaTiO sub 3 electrochemical material. This method, although still employs an internal standard, was found to be very easy and accurate. The required weight fraction of a phase in the mixture to be analysed is determined from the ratio of slopes of two linear plots, designated as the analysis and reference lines, passing through their origins using the least squares method

  20. The Socioeconomic Assessment of Sloping Land Conversion Program in China

    DEFF Research Database (Denmark)

    Liu, Zhen

    with the aim to combat deforestation, ecological degradation, over cultivation of sloping land and soil erosion. However, we also believe it brings changes to the rural economic structure and household livelihood strategy. Applying and developing some empirical and theoretical methods with a large...... decreased in the second round except the positive impact in 2007. Moreover, it is found that there are heterogeneous effects on farm household productivity between the south and north, as well as poor and rich region. In sum, the findings from this thesis highlight that SLCP has significant effects on the...

  1. Slope angle studies from multibeam sonar data on three seamounts in Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Kodagali, V.N.

    Slope angles are powerful morphometric tools. Slope angle studies in manganese nodule areas using the Multi Beam Sonar (MBS) data is useful to the mining geologist. A technique to convert depth grid generated from MBS data to slope angle values data...

  2. Direction of auditory pitch-change influences visual search for slope from graphs

    Science.gov (United States)

    Parrott, Stacey; Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Huntington, Mark D.; Suzuki, Satoru

    2015-01-01

    Linear trend (slope) is important information conveyed by graphs. We investigated how sounds influenced slope detection in a visual search paradigm. Four bar graphs or scatter plots were presented on each trial. Participants looked for a positive-slope or a negative-slope target (in blocked trials), and responded to targets in a go/no-go fashion. For example, in a positive-slope-target block, the target graph displayed a positive slope while other graphs displayed negative slopes (a go trial), or all graphs displayed negative slopes (a no-go trial). When an ascending or descending sound was presented concurrently, ascending sounds slowed detection of negative-slope targets whereas descending sounds slowed detection of positive-slope targets. The sounds had no effect when they immediately preceded the visual search displays, suggesting that the results were due to crossmodal interaction rather than priming. The sounds also had no effect when targets were words describing slopes, such as “positive,” “negative,” “increasing,” or “decreasing,” suggesting that the results were unlikely due to semantic-level interactions. Manipulations of spatiotemporal similarity between sounds and graphs had little effect. These results suggest that ascending and descending sounds influence visual search for slope based on a general association between the direction of auditory pitch-change and visual linear trend. PMID:26541054

  3. Wood-soil interactions in soil bioengineering slope stabilization works

    Directory of Open Access Journals (Sweden)

    Moscatelli MC

    2009-10-01

    Full Text Available In this work we propose the use of soil quality indicators with the aim of assessing the environmental impact of soil bioengineering works. This study was carried out in central Italy where soil bioengineering slope stabilization works were established using chestnut wood. In particular the goal of this study was to determine the occurrence of a wood-effect, that is changes of soil properties due to the presence of decomposing logs in two sites characterized by different time span since works setting up. The presence of the logs did not affect soil physico-chemical properties. Conversely, soil biochemical properties such as soil microbial biomass, basal and cumulative respiration activities as well as microbial indexes, were influenced by the presence of the logs confirming the role of these bioindicators as early predictors of changes occurring in soil. Although a general positive trend was observed for the biochemical properties at both sites with respect to the control soils, significant differences were recorded mainly at the site where works were established six years before soil sampling. Soil bioengineering slope stabilization works establish a positive feed-back which ultimately can benefit plants; in fact the increase in microbial mineralization activity can enhance nutrient cycling and thus promote adequate growth conditions for the plant cuttings used in the wooden-work.

  4. SNOW ACCUMULATION DYNAMICS ON SLOPES AND DITCHES FOR UNSOLVED GROOVE

    Directory of Open Access Journals (Sweden)

    N. Yu. Alimova

    2012-11-01

    Full Text Available Statement of the problem. The problems of estimating a residual snow load capacity for unopen grooves and predicting the beginning of snow accumulation on the driveway have been discussed.Results. The mathematical model for the calculation of snow accumulation on slopes and in ditches of grooves is presented which takes into account snowfall accumulations. The balance equation for the calculation of snow accumulations in an unopen groove is suggested. The calculation formula of snow container for a typical unopen groove, which takes into account its depth is presented. The dates of full filling of unopen grooves, slopes and ditches have been predicted. The calculations are performed for typical cross-section profiles of hollow of over 1.0 m in depth.Conclusions. It has been concluded that a knowledge about snow accumulations is necessary in the calculation and predicting the beginning of snow accumulation on the driveway. The problem of a further research addressing the choice of a proper snow removal technique based on the re-sults of engineering monitoring has been discussed.

  5. Sport Injuries in Iranian Skiers (Shemshak Slope 2000-2001

    Directory of Open Access Journals (Sweden)

    M Motamedy

    2002-09-01

    Full Text Available Background: Sport medicine is a relatively new scientific branch in Iran. In order to evaluate sport injuries in Iranian skiers we examined and followed all ski players who was injured while skiing in Shemshak slope during a skiing season (January to April 2000. Materials and Methods: During a period of 3 months, a total of 32050 persons skied in Shemshak slope and 76 case of injuries were identified; the injury rate was calculated as 2.3/1000 skiers. Among the injured organs knee (32% and head and neck region (20% were respectively the most common sites of injury. Sprain of the medial collateral ligament was the most frequent knee injury (28% of the cases. 26.7% of the injured cases were amateurs and 21% of them used hired ski instruments. Results: In this study such factors as lack of exercise before skiing, fatigue and time of skiing (beginning or end of the season were not found to be related to the injury rate. However, head and neck injuries in contrast to knee injuries were most frequent in the end of the season (P<0.01. Conclusion: This study confirms the necessity of greater care of knee joints during skiing and probable need of wearing helmet for head protection in the end of skiing season. More studies are necessary to clarify other details regarding sport injuries in skiers.

  6. Precision Tiltmeter as a Reference for Slope Measuring Instruments

    International Nuclear Information System (INIS)

    The next generation of synchrotrons and free electron lasers require extremely high-performance x-ray optical systems for proper focusing. The necessary optics cannot be fabricated without the use of precise optical metrology instrumentation. In particular, the Long Trace Profiler (LTP) based on the pencil-beam interferometer is a valuable tool for low-spatial-frequency slope measurement with x-ray optics. The limitations of such a device are set by the amount of systematic errors and noise. A significant improvement of LTP performance was the addition of an optical reference channel, which allowed to partially account for systematic errors associated with wiggling and wobbling of the LTP carriage. However, the optical reference is affected by changing optical path length, non-homogeneous optics, and air turbulence. In the present work, we experimentally investigate the questions related to the use of a precision tiltmeter as a reference channel. Dependence of the tiltmeter performance on horizontal acceleration, temperature drift, motion regime, and kinematical scheme of the translation stage has been investigated. It is shown that at an appropriate experimental arrangement, the tiltmeter provides a slope reference for the LTP system with accuracy on the level of 0.1 (micro)rad (rms)

  7. Tolerable Time-Varying Overflow on Grass-Covered Slopes

    Directory of Open Access Journals (Sweden)

    Steven A. Hughes

    2015-03-01

    Full Text Available Engineers require estimates of tolerable overtopping limits for grass-covered levees, dikes, and embankments that might experience steady overflow. Realistic tolerance estimates can be used for both resilient design and risk assessment. A simple framework is developed for estimating tolerable overtopping on grass-covered slopes caused by slowly-varying (in time overtopping discharge (e.g., events like storm surges or river flood waves. The framework adapts the well-known Hewlett curves of tolerable limiting velocity as a function of overflow duration. It has been hypothesized that the form of the Hewlett curves suggests that the grass erosion process is governed by the flow work on the slope above a critical threshold velocity (referred to as excess work, and the tolerable erosional limit is reached when the cumulative excess work exceeds a given value determined from the time-dependent Hewlett curves. The cumulative excess work is expressed in terms of overflow discharge above a critical discharge that slowly varies in time, similar to a discharge hydrograph. The methodology is easily applied using forecast storm surge hydrographs at specific locations where wave action is minimal. For preliminary planning purposes, when storm surge hydrographs are unavailable, hypothetical equations for the water level and overflow discharge hydrographs are proposed in terms of the values at maximum overflow and the total duration of overflow. An example application is given to illustrate use of the methodology.

  8. Bioengineering case studies sustainable stream bank and slope stabilization

    CERN Document Server

    Goldsmith, Wendi; McCullah, John

    2014-01-01

    This unique volume describes and evaluates 30 projects from across the United States where bio-stabilization was employed to address a detrimental naturally occurring process or byproduct of the built environment. Bio-stabilization (or soil bioengineering) refers to the use of plant materials, primarily live cuttings, arranged in the ground in different arrays to reinforce soils and protect upland slopes and/or stream banks against surficial erosion and shallow slope failures. Examples included in the collection represent different regions of the country and their specific conditions and challenges. Each project is illustrated with a number of distinctive photographs to support the reader's understanding and showcase the wide scope of projects and techniques presented. This book also: ·         Presents a range of well-documented case studies on key techniques and best practices for bio-stabilization projects ·         Emphasizes evaluation and comparison of different techniques and challeng...

  9. Soil-root Shear Strength Properties of Some Slope Plants

    International Nuclear Information System (INIS)

    Rapid development in hilly areas in Malaysia has become a trend that put a stress to the sloping area. It reduces the factor of safety by reducing the resistant force and therefore leads to slope failure. Vegetation plays a big role in reinforcement functions via anchoring the soils and forms a binding network within the soil layer that tied the soil masses together. In this research, three plant species namely Acacia mangium, Dillenia suffruticosa and Leucaena leucocaphala were assessed in term of their soil-root shear strength properties. Our results showed that Acacia mangium had the highest shear strength values, 30.4 kPa and 50.2 kPa at loads 13.3 kPa and 24.3 kPa, respectively. Leucaena leucocaphala showed the highest in cohesion factor, which was almost double the value in those of Dillenia suffruticosa and Acacia mangium. The root profile analysis indicated Dillenia suffruticosa exhibited the highest values in both root length density and root volume, whilst Leucaena leucocaphala had the highest average of root diameter. (author)

  10. Shock wave propagation along constant sloped ocean bottoms.

    Science.gov (United States)

    Maestas, Joseph T; Taylor, Larissa F; Collis, Jon M

    2014-12-01

    The nonlinear progressive wave equation (NPE) is a time-domain model used to calculate long-range shock propagation using a wave-following computational domain. Current models are capable of treating smoothly spatially varying medium properties, and fluid-fluid interfaces that align horizontally with a computational grid that can be handled by enforcing appropriate interface conditions. However, sloping interfaces that do not align with a horizontal grid present a computational challenge as application of interface conditions to vertical contacts is non-trivial. In this work, range-dependent environments, characterized by sloping bathymetry, are treated using a rotated coordinate system approach where the irregular interface is aligned with the coordinate axes. The coordinate rotation does not change the governing equation due to the narrow-angle assumption adopted in its derivation, but care is taken with applying initial, interface, and boundary conditions. Additionally, sound pressure level influences on nonlinear steepening for range-independent and range-dependent domains are used to quantify the pressures for which linear acoustic models suffice. A study is also performed to investigate the effects of thin sediment layers on the propagation of blast waves generated by explosives buried beneath mud line. PMID:25480048

  11. A Simple Statistic for Comparing Moderation of Slopes and Correlations

    Directory of Open Access Journals (Sweden)

    MichaelSmithson

    2012-07-01

    Full Text Available Given a linear relationship between two continuous random variables $X$ and $Y$ that may be moderated by a third, $Z$, the extent to which the correlation $\\rho$ is (unmoderated by $Z$ is equivalent to the extent to which the regression coefficients $\\beta_y$ and $\\beta_x$ are (unmoderated by $Z$ iff the variance ratio $\\sigma_y^2/\\sigma_x^2$ is constant over the range or states of $Z$. Otherwise, moderation of slopes and of correlations must diverge. Most of the literature on this issue focuses on tests for heterogeneity of variance in $Y$, and a test for this ratio has not been investigated. Given that regression coefficients are proportional to $\\rho$ via this ratio, accurate tests and estimations of it would have several uses. This paper presents such a test for both a discrete and continuous moderator and evaluates its Type I error rate and power under unequal sample sizes and departures from normality. It also provides a unified approach to modeling moderated slopes and correlations with categorical moderators via structural equations models.

  12. Soil slips and debris flows on terraced slopes

    Science.gov (United States)

    Crosta, G. B.; Dal Negro, P.; Frattini, P.

    Terraces cover large areas along the flanks of many alpine and prealpine valleys. Soil slips and soil slips-debris flows are recurrent phenomena along terraced slopes. These landslides cause damages to people, settlements and cultivations. This study investigates the processes related to the triggering of soil slip-debris flows in these settings, analysing those occurred in Valtellina (Central Alps, Italy) on November 2000 after heavy prolonged rainfalls. 260 landslides have been recognised, mostly along the northern valley flank. About 200 soil slips and slumps occurred in terraced areas and a third of them evolved into debris flows. Field work allowed to recognise the settings at soil slip-debris flow source areas. Landslides affected up to 2.5 m of glacial, fluvioglacial and anthropically reworked deposits overlying metamorphic basement. Laboratory and in situ tests allowed to characterise the geotechnical and hydraulic properties of the terrains involved in the initial failure. Several stratigraphic and hydrogeologic factors have been individuated as significant in determining instabilities on terraced slopes. They are the vertical changes of physical soil properties, the presence of buried hollows where groundwater convergence occurs, the rising up of perched groundwater tables, the overflow and lateral infiltration from superficial drainage network, the runoff concentration by means of pathways and the insufficient drainage of retaining walls.

  13. The Influence of Increasing Rain and Earthquake Activities on Landslide Slope Stability in Forest Areas

    Science.gov (United States)

    Kubota, T.; Aditian, A.

    2014-12-01

    Deriving the analysis of rainfall data in various mountainous locations, increase in rainfall that is deemed to be induced by the global climate change is obvious in Kyushu district, western Japan. On this point of view, its long term impact on the forest slope stability is analyzed with field investigation and numerical simulation such as finite element method (FEM). On the other hand, the influence of earthquake such as cracks on the slope due to seismic vibration was also analyzed with FEM. In this case, the slope stability analysis to obtain the factor of safety "Fs" is conducted. Here, in case of the Fs > 1.0, the slope is stable. In addition, the slope stabilizing effect of the forest mainly due to the roots strength is evaluated on some unstable slopes. Simultaneously, a holistic estimation over landslide groups is conducted by comparing "Fs" on forest slopes with non- forest slopes. Therefore, the following conclusions are obtained: 1) Comparing the Fs without increased rainfall from the previous decade and the one with actual rainfall, the former case is 1.04 ~1.06 times more stable than the latter. 2) On the other hand, the forest slopes are estimated to be up to approximately 1.5 to 2.5 times more stable than the slope without forest. Therefore, the slope stabilizing effect by the forest is much higher than the increasing rainfall influence i.e. the climate change effect. These results imply that an appropriate forest existence is important under the climate change condition to prevent forest slope degradation. 3) Comparing with the destabilization of the slope by seismic activities (vibration) due to the reduction of soil strength and "cracks = slope deformation" (8~9 % to 30% reduction in Fs even after an earthquake of 490gal), the influence of the long term rainfall increase on slopes (such as 1% decrease in Fs) is relatively small in the study area.

  14. Bird diversity and land use on the slopes Bird diversity and land use on the slopes, Tanzania

    OpenAIRE

    Eija Soini

    2011-01-01

    This study of bird distribution in the main land-use categories of the slopes of Mt Kilimanjaro,Tanzania, aims at understanding potential impacts of the land-use changes on birds. A land-use map of the study area was derived from a Landsat image, and land-use change information came from an earlier study by the author. Bird data were collected by observations along timed, standardized walks. Shannon (1948) indices of bird diversity for highlands, bushland and lowlands were 3.29, 2.99, and 2.6...

  15. Estimating significances of differences between slopes: A new methodology and software

    Directory of Open Access Journals (Sweden)

    Vasco M. N. C. S. Vieira

    2013-09-01

    Full Text Available Determining the significance of slope differences is a common requirement in studies of self-thinning, ontogeny and sexual dimorphism, among others. This has long been carried out testing for the overlap of the bootstrapped 95% confidence intervals of the slopes. However, the numerical random re-sampling with repetition favours the occurrence of re-combinations yielding largely diverging slopes, widening the confidence intervals and thus increasing the chances of overlooking significant differences. To overcome this problem a permutation test simulating the null hypothesis of no differences between slopes is proposed. This new methodology, when applied both to artificial and factual data, showed an enhanced ability to differentiate slopes.

  16. SLOPE STABILITY ANALYSIS OF KALLAR-COONOOR HILL ROAD STRETCH OF THE NILGIRIS

    OpenAIRE

    P. Nalina; T.MEENAMBAL; R. Sathyanarayan Sridhar

    2014-01-01

    The stability of slopes is always under severe threats in many parts of Western Ghats, especially in Kallar-Coonoor hill road stretch, causing disruption, loss of human life and economy. To minimize the instability of soil slope in between Kallar-Coonoor, a critical evaluation of roads is required. The stability of slopes depends on the soil shear strength parameters such as Cohesion, Angle of internal friction, Unit weight of soil and Slope geometry. The stability of a slope is measured by i...

  17. APPLICATION OF GPS DISPLACEMENT MEASUREMENTS FOR MONITORING SLOPE DISPLACEMENTS AT A TUNNEL ENTRANCE

    Science.gov (United States)

    Matsuda, Hiroaki; Tsutsui, Takanori; Ikeda, Keisuke; Shimizu, Norikazu

    A GPS displacement measurement system has been widely used for monitoring the slope stability. Tall trees and other obstacles on the slope often cause a disturbance to the signals transmitted from the satellites and a degradation of the measurement accuracy. It is an important issue to be overcome for applying GPS to monitoring the deformation of slopes. In this paper, "the mask method" developed by the authors is adopted for improving the measurement accuracy under overhead obstacles. It is proven that the method was effective for monitoring a slope at a tunnel entrance during tunnel construction. The measured results of three dimensional displacements are discussed for assessing the slope stability.

  18. Value of magnetic resonance imaging in the mid-term follow-up of osteochondritis dissecans of the femoral condyle and talus; Die Bedeutung der Magnetresonanztomographie fuer die Verlaufskontrolle der Osteochondrosis dissecans am Knie- und Sprunggelenk

    Energy Technology Data Exchange (ETDEWEB)

    Bachmann, G.; Rominger, M.; Rau, W.S. [Giessen Univ. (Germany). Abt. Diagnostische Radiologie; Juergensen, I. [Giessen Univ. (Germany). Orthopaedische Klinik

    1999-11-01

    Purpose: Definition of the prognostic value of clinical and morphological findings in the mid-term follow-up of OCD of the femoral condyle and talus. Demonstration of the consolidation of OCD on MRI depending on different therapies. Materials and Methods: 76 patients were examined before and at an average of 30 months after conservative or surgical therapy using T{sub 1} and T{sub 2} weighted SE and 3D-FISP sequences and contrast enhanced studies. Six clinical (age, gender, site, duration and severity of symptoms, therapy) and six morphological (size, signal intensity, fragmentation, contrast enhancement, condition of cartilage, staging) data were registered on first MRI and correlated with the degree of consolidation of OCD (partial and complete remission, no change and progression) on control MRI. Results: Patients under 17 years showed partial or complete remissions in 73%, those of 17 years or older in 33%. Conservatively treated patients had a higher remission rate (54%) than those treated with different surgical techniques (drilling 50%, refixation 43%, abrasio 38%). Small OCDs had a higher remission rate than large lesions (63% vs. 33%). OCDs covered with intact cartilage healed better than lesions with chondral defects (61% vs. 26%). Contrast enhancing fragments had a better prognosis than non-enhancing lesions (100% vs. 40%). Conclusions: Prognosis of OCD can be better estimated when size of OCD, condition of cartilage and enhancement of contrast agent is graduated with MRI and patient age is registered. The consequences for therapy planning are great. (orig.) [German] Ziel: Bewertung von MRT-Befunden und klinischen Daten als Prognoseparameter fuer den mittelfristigen Heilungsverlauf der Osteochondrosis dissecans (OCD) an Knie- und Sprunggelenk. Zudem wird die Konsolidierung der OCD unter verschiedenen Therapieformen untersucht. Material und Methoden: 76 Patienten wurden vor und durchschnittlich 30 Monaten nach konservativer bzw. chirurgischer Therapie einer OCD MR-tomographisch untersucht (T{sub 1}-gewichtete SE-Sequenz ohne und mit Kontrastmittel, T{sub 2}-gewichtete SE-Sequenz, FISP-3D-Sequenz). Klinische Daten (Alter, Geschlecht, Lokalisation, Anamnesedauer, Symptomatik und Art der Therapie) und MRT-Befunde (Groesse, Signal, Sinterung, Kontrastmittelaufnahme, Knorpelzustand, Stadium) wurden mit dem im Kontroll-MRT erkennbaren Heilungszustand (partielle bzw. komplette Remission Konstanz, Progression) korreliert. Ergebnisse: Bei Patienten unter 17 Jahren wurde eine partielle bzw. komplette Remission in 73%, bei Patienten ueber 17 Jahren in 33% registriert. Die konservative Behandlung fuehrte zu einer etwas hoeheren Remissionsrate (54%) als die chirurgischen Therapieformen (Bohrung 50%, Refixation 43%, Abrasio 38%). Kleine OCDs heilten besser als grosse (63% vs. 33%), Herde mit intaktem Knorpel besser (61%) als jene mit Knorpeldefekten (26%) und nach Kontrastmittelgabe anreichernde Fragmente wesentlich haeufiger (100%) als nicht anreichernde (40%). Schlussfolgerung: Wichtigster klinischer Parameter fuer die Prognose der OCD ist das Alter. Unter den MRT-Kriterien stehen die Groesse des Defekts, der Zustand des Knorpelbelags und die Kontrastmittelaufnahme im Fragment an der Spitze. Die Konsequenzen dieser Befunde fuer die Therapieplanung sind betraechtlich. (orig.)

  19. Spatial Coupling Among Landslides, Geological Structures, Cataclinal Slopes, and Fluvial Knick Zones in Nepal Himalayas

    Science.gov (United States)

    Ojha, T. P.; DeCelles, P. G.

    2014-12-01

    This work aims to identify potential landslide hazard zones in the event of heavy precipitation and seismic activity by examining spatial relationships among existing landslides, earthquake epicenters, fault zones, cataclinal (dip) slopes, anaclinal (escarp) slopes, and river steepness index in the Nepal Himalaya. In order to understand this relationship we have mapped existing landslides on Google Earth images and ESRI base maps, assembled high-resolution digital topographic data by digitizing Nepal Government published topographic maps, and gathered geological data from detailed field mapping and compilation of published geological maps. Slope angle and aspect, and dip direction and angle were extracted from GIS-based digital topographical and geological datasets to develop the new slope maps with cataclinal (dip) and anaclinal (escarp) slope distributions. Longitudinal river profiles were also extracted from high resolution DEM's derived from manually digitized contours. The slope maps with cataclinal and anaclinal slope distributions, earthquake epicenters, major geological structures, longitudinal river profiles, and landslide inventories were visualized in ESRI ArcMap 10.2 to examine the spatial correlation among landslides, fault zones, cataclinal slopes and river steepness index. We have found that landslides are spatially correlated with cataclinal slopes and fluvial knick zones with high steepness index in certain thrust boundaries. The main finding of this work is that the topographic slope threshold alone is a crude measure of landslide susceptibility. The analysis of slope using the geometric relationship among topography and geological bedding is crucial for determining landslide susceptibility in the Himalayan region.

  20. Failure Modes and Stability of Rock Mass Slope Containing Multi-weak Interlayer

    Directory of Open Access Journals (Sweden)

    Liu Jie-Qun

    2013-01-01

    Full Text Available The phenomena of rock mass slope with multi-weak interlayer can be found in real engineering frequently. It is worthy to study the influence of multi-weak interlayer on failure of rock mass slope. Based on the shear strength reduction finite element method, stability and failure surface of rock mass slope with different parameters had been studied, the failure mechanism of rock mass slope containing multi-weak interlayer has been analyzed. It can be found that the stability of consequent rock slope decreased first and increased later with increasing of rock stratum inclination which got its minimal value at 30° of rock stratum inclination. The stability of anti-dip rock slope fluctuated with increasing of rock stratum inclination which got its maximal value at 135° of rock stratum inclination. Whether consequent rock slope or anti-dip rock slope, the stability of slope decreased with angle of slope increased. Although, the stability of rock slope reduced or weakened by multi-weak interlayer, the failure and stability is controlled by parameters of rock mass mostly.

  1. Effect of Different Groundwater Levels on Seismic Dynamic Response and Failure Mode of Sandy Slope.

    Science.gov (United States)

    Huang, Shuai; Lv, Yuejun; Peng, Yanju; Zhang, Lifang; Xiu, Liwei

    2015-01-01

    Heavy seismic damage tends to occur in slopes when groundwater is present. The main objectives of this paper are to determine the dynamic response and failure mode of sandy slope subjected simultaneously to seismic forces and variable groundwater conditions. This paper applies the finite element method, which is a fast and efficient design tool in modern engineering analysis, to evaluate dynamic response of the slope subjected simultaneously to seismic forces and variable groundwater conditions. Shaking table test is conducted to analyze the failure mode and verify the accuracy of the finite element method results. The research results show that dynamic response values of the slope have different variation rules under near and far field earthquakes. And the damage location and pattern of the slope are different in varying groundwater conditions. The destruction starts at the top of the slope when the slope is in no groundwater, which shows that the slope appears obvious whipping effect under the earthquake. The destruction starts at the toe of the slope when the slope is in the high groundwater levels. Meanwhile, the top of the slope shows obvious seismic subsidence phenomenon after earthquake. Furthermore, the existence of the groundwater has a certain effect of damping. PMID:26560103

  2. Research on the Slope Green and Environment Protection Using Dynamical Game Theory

    Directory of Open Access Journals (Sweden)

    Juan Wan

    2013-10-01

    Full Text Available This study aims to investigate the slope green and environment protection in China. In ecological slope protection, the plant roots can achieve the ecological vegetation restoration of the slope surface. Hence the slope environment can be protected significantly. However, there is still lack of efficient policy to support the implementation of nationwide slope green program to facilitate the development of slope green and environment protection technologies. Hence, the reasonable relationship between the slope green and environment protection and the national policy is very important. Literature review indicates that very little work has been done to address this issue. In order to investigate the relationship between the slope green and environment protection and the national policy, this study presents a new analysis method based on the dynamical Game theory. The game between the slope green and environment protection and the national policy can be regarded as a dynamical economic process, the optimized implementation strategy for the slope green and environment protection under the national support can be obtained by the use of dynamical game analysis. The stability analysis and the balance analysis have been discussed for the proposed game model. The analysis result shows that the government should increase financial support as well as establish corresponding punishment mechanism to encourage different policies and practices for slope green and environment protection and hence a win-win situation can be achieved.

  3. Slope wavenumber spectrum models of capillary and capillary-gravity waves

    Science.gov (United States)

    Jia, Yongjun; Zhang, Jie; Wang, Yanfeng

    2010-03-01

    Capillary and capillary-gravity waves possess a random character, and the slope wavenumber spectra of them can be used to represent mean distributions of wave energy with respect to spatial scale of variability. But simple and practical models of the slope wavenumber spectra have not been put forward so far. In this article, we address the accurate definition of the slope wavenumber spectra of water surface capillary and capillary-gravity waves. By combining the existing slope wavenumber models and using the dispersion relation of water surface waves, we derive the slope wavenumber spectrum models of capillary and capillary-gravity waves. Simultaneously, by using the slope wavenumber models, the dependence of the slope wavenumber spectrum on wind speed is analyzed using data obtained in an experiment which was performed in a laboratory wind wave tank. Generally speaking, the slope wavenumber spectra are influenced profoundly by the wind speed above water surface. The slope wavenumber spectrum increases with wind speed obviously and do not cross each other for different wind speeds. But, for the same wind speed, the slope wavenumber spectra are essentially identical, even though the capillary and capillary-gravity waves are excited at different times and locations. Furthermore, the slope wavenumber spectra obtained from the models agree quite well with experimental results as regards both the values and the shape of the curve.

  4. Soil erosion spatial distribution patterns of different slopes by using 137Cs tracer

    International Nuclear Information System (INIS)

    The soil erosion spatial patterns of several slopes were studied through measuring 137Cs in the top layer soil on the different slopes. The results show that all the soil erosion spatial distribution patterns are in fluctuate trend. The soil erosion is more severe in the middle part on the short farmland slope. The erosion pattern of the gully base show violent head ward erosion. Because of the influence of vegetation cover and other factor, the erosion patterns on the gully slopes are complex. The soil erosion differs obviously with the compound slopes of the same slope gradient and slope length. In general, the main factor that influence soil erosion is the change of the micro-landforms in a long period

  5. Dynamic stability and failure modes of slopes in discontinuous rock mass

    International Nuclear Information System (INIS)

    The stability of rock slopes during earthquakes are of great concern in rock engineering works such as highway, dam, and nuclear power station constructions. As rock mass in nature is usually discontinuous, the stability of rock slopes will be geverned by the spatial distribution of discontinuities in relation with the geometry of slope and their mechanical properties rather than the rock element. The authors have carried out some model tests on discontinuous rock slopes using three different model tests techniques in order to investigate the dynamic behaviour and failure modes of the slopes in discontinuous rock mass. This paper describes the findings and observations made on model rock slopes with various discontinuity patterns and slope geometry. In addition some stability criterions are developed and the calculated results are compared with those of experiments. (author)

  6. Check dams effects on sediment transport in steep slope flume

    Science.gov (United States)

    Piton, Guillaume; Recking, Alain

    2014-05-01

    Depending on many influences (geology, relief, hydrology, land use, etc.) some mountainous watershed are prone to cause casualties and facilities damages. Large amounts of sediments episodically released by torrents are often the biggest problem in torrent related hazard mitigation. Series of transversal structures as check dams and ground sills are often used in the panel of risk mitigation technics. A large literature exits on check dams and it mainly concerns engineering design, e.g. toe scouring, stability stress diagram, changes in upper and lower reaches equilibrium slopes. Check dams in steep slope rivers constitute fixed points in the bed profile and prevent general bed incision. However their influence on sediment transport once they are filled is not yet clear. Two flume test campaigns, synthetize in Table 1, were performed to investigate this question: Table 1 : experiment plan Run (duration) Ref1 (50h)CD1a (30h)CD1b (30h)Ref2 (92h)CD2 (18h) Solid feeding discharge (g.s^-1) 44 44 44 60 60 Number of check dams none 1 3 none 2 A nearly 5-m-long, 10-cm-wide and 12%-steep flume was used. The water discharge was set to 0,55 l/s in all runs. A mixture of poorly sorted natural sediments with diameters between 0.8 and 40 mm was used. An open solid-discharge-feeding circuit kept the inlet sediment flux constant during all experiments. As both feeding rates did not present variation, changes in outlet solid discharge were assumed to be due to bed variations in the bed storage. We observed strong fluctuations of solid flux and slope in each reaches of all runs between: (i) steep aggradating armoured bed and (ii) less steep and finer bed releasing bedload sheets during erosion events and inducing bedload pulses. All experiments showed consistent results: transported volume associated with erosion event decreased with the length between two subsequent check dams. Solid transversal structures shorten the upstream erosion-propagation and avoid downstream change in the bed level. As long as they are not buried by too strong aggradation they allow a 'bed level independence' between reaches. On the long term, as the total inlet flux is kept constant, a decrease in transported volumes induces an increase in the erosion event frequency: sediment releases are more frequent but littler. As proposed by Poncet (1995), check dams participate efficiently in hazard mitigation because 'they release in retail what torrents would too abruptly delivered wholesale'. Reference : Poncet, A. "Restauration et conservation des terrains en montagne." Office national des forêts, Paris (1995).

  7. Morphologic and sedimentologic characteristics of continental slope box slides offshore Fraser Island, Queensland, Australia

    Science.gov (United States)

    Fletcher, Melissa; Hubble, Thomas; Clarke, Samantha; Airey, David; Yu, Phyllis; Southern Surveyor V01-2013, Scientific Party RV

    2014-05-01

    The Fraser Island Slide complex is located on eastern Australia's continental slope offshore Fraser Island in southern Queensland. Morphologic, sedimentologic and geomechanical properties data for two submarine landslides, the 'North Fraser Island Upper Slope Slide' (upper slope slide) and the 'Fraser Island Middle Slope Slide' (middle slope slide) are described. Both of these features are box-shaped, slide scars from which rectangular slabs of material have been shed. The upper slope slide is situated at a water depth of approximately 750 m at the northern end of the Fraser Canyon. The head of this slide has apparently detached from a structural surface comprised of a Miocene reef complex located beneath the continental shelf edge; this slide is estimated to be 25 square kilometres in area and an average of 100m thick. The middle slope slide is situated in 1500 m of water at the southern end of the Fraser Canyon. It estimated to be 12 square kilometres in area and 50 m thick. Cores taken in the continental slope within both slides are long (upper slope 5.65 m, middle slope 3.64 m) and are dominantly comprised of hemipelagic mud. Cores taken adjacent to both slides are short (upper slope 1.33m, middle slope 0.43m) and terminate in stiff muds of suspected Miocene or Pliocene age. Additionally, the 1.33 m core on the slope adjacent to the upper slide presents a near surface layer of upper-fining of coarse to fine shelly sand which we interpret to be a turbidite deposit, this layer was deposited within hemipelagic muds which are ubiquitously present on the upper eastern Australian Continental Slope in New South Wales and Southern Queensland.

  8. Center Line Slope Analysis in Two-Dimensional Electronic Spectroscopy.

    Science.gov (United States)

    Šanda, František; Perlík, Václav; Lincoln, Craig N; Hauer, Jürgen

    2015-11-01

    Center line slope (CLS) analysis in 2D infrared spectroscopy has been extensively used to extract frequency-frequency correlation functions of vibrational transitions. We apply this concept to 2D electronic spectroscopy, where CLS is a measure of electronic gap fluctuations. The two domains, infrared and electronic, possess differences: In the infrared, the frequency fluctuations are classical, often slow and Gaussian. In contrast, electronic spectra are subject to fast spectral diffusion and affected by underdamped vibrational wavepackets in addition to Stokes shift. All these effects result in non-Gaussian peak profiles. Here, we extend CLS-analysis beyond Gaussian line shapes and test the developed methodology on a solvated molecule, zinc phthalocyanine. We find that CLS facilitates the interpretation of 2D electronic spectra by reducing their complexity to one dimension. In this way, CLS provides a highly sensitive measure of model parameters describing electronic-vibrational and electronic-solvent interaction. PMID:26463085

  9. Slope Hazard and Risk Assessment in the Tropics: Malaysia' Experience

    Science.gov (United States)

    Mohamad, Zakaria; Azahari Razak, Khamarrul; Ahmad, Ferdaus; Manap, Mohamad Abdul; Ramli, Zamri; Ahmad, Azhari; Mohamed, Zainab

    2015-04-01

    The increasing number of geological hazards in Malaysia has often resulted in casualties and extensive devastation with high mitigation cost. Given the destructive capacity and high frequency of disaster, Malaysia has taken a step forward to address the multi-scale landslide risk reduction emphasizing pre-disaster action rather than post-disaster reaction. Slope hazard and risk assessment in a quantitative manner at regional and national scales remains challenging in Malaysia. This paper presents the comprehensive methodology framework and operational needs driven by modern and advanced geospatial technology to address the aforementioned issues in the tropics. The Slope Hazard and Risk Mapping, the first national project in Malaysia utilizing the multi-sensor LIDAR has been critically implemented with the support of multi- and trans-disciplinary partners. The methodological model has been formulated and evaluated given the complexity of risk scenarios in this knowledge driven project. Instability slope problems in the urban, mountainous and tectonic landscape are amongst them, and their spatial information is of crucial for regional landslide assessment. We develop standard procedures with optimal parameterization for susceptibility, hazard and risk assessment in the selected regions. Remarkably, we are aiming at producing an utmost complete landslide inventory in both space and time. With the updated reliable terrain and landscape models, the landslide conditioning factor maps can be accurately derived depending on the landslide types and failure mechanisms which crucial for hazard and risk assessment. We also aim to improve the generation of elements at risk for landslide and promote integrated approaches for a better disaster risk analysis. As a result, a new tool, notably multi-sensor LIDAR technology is a very promising tool for an old geological problem and its derivative data for hazard and risk analysis is an effective preventive measure in Malaysia. Geological, morphological, and physical factors coupled with anthropogenic activities made the spatiotemporal prediction of possible slope failures very challenging. Changing climate and land-use-and-land-cover required a dynamic geo-system approach for assessing multi-hazard in Malaysia and it is still a great challenge to be dealt with. We also critically discussed the capability, limitation and future direction of geo-information tools particularly the active sensors for systematically providing the spatial input towards landslide hazard and possible risk. The cost-and-benefit of developed methods compared to traditional mapping techniques is also elaborated. This paper put forth the critical and practical framework ranging from updating landslide inventory to mitigating landslide risk as an attempt to support the establishment of a comprehensive landslide risk management in Malaysia. The advancement of multistage processing sequence based on airborne-, and ground-based laser remote sensing technology coupling with the sophisticated satellite positioning system, advanced geographical information system and expert knowledge leading to a better understanding of the landslide processes and their dynamics in time and space. Given the state-of-the-art of multi-sensor-LIDAR and complexity of tropical environment, this first landslide project carried out at the national scale provides a better indication and recommendation on the use of modern and advanced mapping technology for assessing tropical landslide geomorphology in an objective, reproducible and quantitative manner.

  10. Air-cushion tankers for Alaskan North Slope oil

    Science.gov (United States)

    Anderson, J. L.

    1973-01-01

    A concept is described for transporting oil from the Arctic to southern markets in 10,000-ton, chemically fueled air-cushion vehicles (ACV's) configured as tankers. Based on preliminary cost estimates the conceptual ACV tanker system as tailored to the transportation of Alaskan North Slope oil could deliver the oil for about the same price per barrel as the proposed trans-Alaska pipeline with only one-third of the capital investment. The report includes the description of the conceptual system and its operation; preliminary cost estimates; an appraisal of ACV tanker development; and a comparison of system costs, versatility, vulnerability, and ecological effect with those of the trans-Alaska pipeline.

  11. End depth in steeply sloping rough rectangular channels

    Indian Academy of Sciences (India)

    Subhasish Dey

    2000-02-01

    The paper presents a theoretical model to compute the end depth of a free overfall in steeply sloping rough rectangular channels. A momentum equation based on the Boussinesq approximation is applied to obtain the equation of the end depth. The effect ofstreamline curvature at the free surface is utilized to develop the differential equation for the flow profile upstream of the free overfall of a wide rectangular channel. As direct solutions for the end depth and flow profile cannot be obtained owing to implicit forms of the developed equations, an auto-recursive search scheme is evolved to solve these equations simultaneously. A method for estimation of discharge from the known end depth and Nikuradse equivalent sand roughness is also presented. Results from the present model correspond satisfactorily with experimental observations except for some higher roughnesses.

  12. REVIEW OF HIGH FIELD Q SLOPE, CAVITY MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Gianluigi Ciovati

    2008-01-23

    One of the most interesting phenomenon occurring in superconducting radio-frequency (SRF) cavities made of bulk niobium is represented by a sharp decrease of the quality factor above peak surface magnetic field of about 90 mT and is referred to as "high field Q-slope" or "Q-drop". This phenomenon was observed first in 1997 and since then some effort was devoted to the understanding of the causes behind it. Still, no clear physical interpretation of the Q-drop has emerged, despite several attempts. In this contribution, I will review the experimental results for various cavities measured in many laboratories and I will try to identify common features and differences related to the Q-drop.

  13. Biocorrosive Thermophilic Microbial Communities in Alaskan North Slope Oil Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, Kathleen E.; Gieg, Lisa M.; Parisi, Victoria A.; Tanner, Ralph S.; Green Tringe, Susannah; Bristow, Jim; Suflita, Joseph M.

    2009-09-16

    Corrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon, with standard treatment methods targeting mesophilic sulfatereducing bacteria. In assessing biocorrosion potential at an Alaskan North Slope oil field, we identified thermophilic hydrogen-using methanogens, syntrophic bacteria, peptideand amino acid-fermenting bacteria, iron reducers, sulfur/thiosulfate-reducing bacteria and sulfate-reducing archaea. These microbes can stimulate metal corrosion through production of organic acids, CO2, sulfur species, and via hydrogen oxidation and iron reduction, implicating many more types of organisms than are currently targeted. Micromolar quantities of putative anaerobic metabolites of C1-C4 n-alkanes in pipeline fluids were detected, implying that these low molecular weight hydrocarbons, routinely injected into reservoirs for oil recovery purposes, are biodegraded and provide biocorrosive microbial communities with an important source of nutrients.

  14. SOIL SEQUENCES ALONG A SLOPE OF THE OPALENICA PLAIN

    Directory of Open Access Journals (Sweden)

    Micha? Koz?owski

    2016-01-01

    Full Text Available The paper presents the results of a study on differentiation of the morphological structure of soil and selected physical and chemical properties of soils in toposequence of the Opalenica Plain. The study was conducted in a 1200 m long transect running through a typical soil toposequence for the Polish Lowland, and therefore the results presented in this study can be extrapolated to similar geomorphological conditions of the area. On the basis of pedological cross-section, the following soil units were distinguished: PWspgl – Albic Luvisols (Arenic with glossic properties, PAt – Albic Glossic Retisols (Loamic, PAsp – Albic Glossic Retisols (Aric, Arenic, PAspgg – Albic Glossic Retisols (Aric, Arenic, Oxyaquic, PWsggl – Albic Luvisols (Aric, Arenic, Stagnic with glossic properties, PWgggl – Albic Luvisols (Aric, Loamic, Stagnic with glossic properties, CZgg – Mollic Reductigleyic Eutric Gleysols (Aric, Loamic, CFt – Fluvic Phaeozems (Aric, Arenic. Each of these units has its own specific position in toposequence but the occurrence of Fluvic Phaeozems (Aric, Arenic are associated with geogenetic processes of Mogilnica river. In this work, using a multiple regression analysis a statistically significant relationships between the position of the soils in relief and the terrain slopes and the organic carbon content in Ap horizon, the cation exchangeable capacity, the sum of exchangeable bases and the pH were obtained. Systematic variability of most soil properties of Ap horizon have shown two distances of spatial variation. The first concerns the systematic changes in shorter distance (from 132 to 344 m and can be associated with differences in soil properties between separate soil units. The second distance of spatial correlation ranges from 431 m to 792 m, which testify to the fact that quantitative changes in the properties of soils are realized gradually and distinctly, together with the differentiation of the slope, over several separate cartographic units.

  15. Global High-Accuracy Intercomparison of Slope Measuring Instruments

    International Nuclear Information System (INIS)

    The upcoming generation of high accuracy synchrotron radiation (SR) optics will be characterized by a slope deviation from ideal shape in the range of some 0.05?rad rms at a sampling interval of about 1mm. To certify and improve the measurement capabilities of metrology tools to inspect these stringent specifications, an essential step is a worldwide intercomparison of these measurements based on a set of transfer standards. It is the aim of these cross measurements to verify the ''absolute'' correctness and comparability of the measurement results obtained by the cooperating partners when measuring the topography of specific reference optics (ROs) using their latest metrology tools and methods. Organized by members of the SR-optics community, new national and international cross measurement comparisons of typical synchrotron radiation mirrors have been realized during the last few years: A round robin test by the European COST-program (BESSY, Elettra, ESRF, Soleil) during the years 2004-2005 and a similar cooperation realized by the APS, ESRF and Spring-8 have proceeded. The first results of both projects were presented at the ''Optics and Photonics'' conference in San Diego in August 2005. This work build upon earlier work. The participants of both groups and representatives of other SR-laboratories agreed to start a global cooperation bringing together the two round-robin projects and open these activities to other partners from the SR-community, optical manufacturers and other interested parties. This initiative is intended to start an extensive comparison of various measurement principles and tools and will help to push the frontiers in metrology, and hence production, to a precision well below the current state-of-the-art limit of 0.5?rad rms for slope errors

  16. Olive production systems on sloping land: prospects and scenarios.

    Science.gov (United States)

    de Graaff, Jan; Duran Zuazo, Victor-Hugo; Jones, Nádia; Fleskens, Luuk

    2008-11-01

    The ultimate objective of the EU Olivero project was to improve the quality of life of the rural population and to assure the sustainable use of the natural resources of land and water in the sloping and mountainous olive production systems (SMOPS) areas in Southern Europe. One specific objective was to develop, with end-users, alternative future scenarios for olive orchards in the five Olivero target areas. This paper discusses the development of these scenarios, and their socio-economic and environmental effects. After presenting the different production systems (SMOPS) and their strengths, weaknesses, opportunities and threats, a general overview is given of the medium- and long-term prospects. These have been validated by experts from the olive sector and foresee changes towards abandonment, intensification and organic production. On balance, the changes could lead to lower production of some target areas in future. An analysis of major external factors affecting the future development of SMOPS indicates there will be labour shortages and increased wage rates, reduced subsidies and constant or rising olive oil prices. On the basis of these assumptions, four future scenarios are developed for the five target areas, with the help of a Linear Programming simulation model. The results are presented for two target areas. For the Trás-os-Montes target area in Portugal, three of the four tested scenarios point to a high level of abandonment, while in the most positive scenario the areas under semi-intensive low input and organic SMOPS increase. In the Granada and Jaen target area in Spain, all scenarios hint at intensification, and only the orchards on the steepest slopes are likely to be abandoned. The direction and extent of environmental effects (erosion, fire risk, pollution, water use and biodiversity) differ per scenario, as do the extent of cross-compliance and agri-environmental measures. PMID:17913332

  17. Monte-Carlo Modeling of Some Niger Delta Slope Events

    Directory of Open Access Journals (Sweden)

    M.I. Oladapo

    2009-01-01

    Full Text Available Monte-Carlo modeling has been utilized in this study to simulate seismic P-wave events on four horizons (AA, BB, CC and DD in a Niger Delta Slope environment with the aim of generating AVO attributes. Monte-Carlo modeling undertaken on a well log from the Gulf of Mexico served as a generic model and control. Trends analysis regressions generated in the environment served as input for the models while default parameter in SAVIOR (fluid method was used for establishing reservoir fluid properties. Fourier velocity served as velocity function. The results of the modeling are presented as AVO crossplots for brine sand (background, residual hydrocarbon and commercial hydrocarbon. For each event, offset-dependent synthetic seismograms are also generated using Zoeppritz equations. The AA horizon is typified by incoherent orientations of AVO crossplots. The horizon is thus presumed unconsolidated. The synthetic seismogram generated shows no perceptible amplitude variation with offset on all the models. AVO crossplot of the encountered BB horizon show that most of the commercial hydrocarbon plots and some of the residual hydrocarbon plots fall on quadrant III (bright spot quadrant. Synthetic seismic generated for BB horizon exhibits positive AVO response (soft kick on the commercial hydrocarbon model. A similar but marginal response was obtained on brine saturated BB model. Brine saturated model of the AVO crossplot for CC horizon model plotted mostly on hard sand quadrant. Conversely, presumed commercial hydrocarbon saturated CC is split between the hard sand and soft sand quadrants with low background normal values. The DD horizon is similar to the deep model of the Gulf of Mexico and hence exhibits similar crossplot. Curiously, high background normal (Bn characterized residual hydrocarbon models while unconsolidated gas sand horizons exhibit anomalous characteristics. The AVO crossplot obtained from the Monte-Carlo model could be a robust tool for mapping reservoirs within the Niger Delta Slope.

  18. Permanent monitoring of alpine slope instabilities with L1-GPS

    Science.gov (United States)

    Limpach, Philippe; Geiger, Alain; Su, Zhenzhong; Beutel, Jan; Gruber, Stephan

    2013-04-01

    Since winter 2010/2011, a network of permanent GPS stations is being set up in the Matter Valley (Swiss Alps). The aim is to monitor the time variable movement of potentially instable rock glaciers. The network has been established in the framework of the X-Sense project, currently totaling more than 20 stations. X-Sense is an interdisciplinary project for monitoring alpine mass movements at multiple scales, funded by the Swiss federal program Nano-Tera within the Swiss Science Foundation. The X-Sense stations consist of low-cost L1 GPS receivers coupled with inclinometers. A part of the stations allow for on-line data transmission. The data of the X-Sense L1 GPS network is operationally processed on a daily basis with Bernese GPS software, in a fully automated processing chain. In addition, real-time solutions are computed for the on-line stations. The geodetic potential of low-cost GPS receivers for the precise monitoring of slope instabilities in mountain areas was previously investigated in a feasibility study. It is shown that low-cost GPS units are able to provide reliable and continuous time series of surface displacements at cm-level accuracy in harsh environment, using adequate differential processing techniques. Enhanced algorithms were developed to derive accurate time series of surface velocities based on the GPS displacements. It was shown that the low-cost GPS receivers allow to reliably observe surface velocities even below 1 cm/day, as well as to detect small and short-term velocity changes. In addition, the time series of more than 2 years obtained reveal the capability to detect seasonal velocity variations, as well as inter-annual variations of the velocity pattern. By providing continuous observations of surface motion, the GPS-based permanent monitoring contributes to the understanding of processes linked to permafrost-related slope instabilities.

  19. Limitations of Deterministic Modelling of Slope Stability on Volcanic Edifices

    Science.gov (United States)

    Burrell, R. V.; Pinkerton, H.; Binley, A.

    2004-12-01

    The conditions leading to the 18 May 1980 sector collapse of Mount St Helens have been the subject of a number of detailed investigations. Preservation of the initial failure plane(s) allowed Voight et al. (1983) and Donnadieu et al. (2001) to undertake back analyses and determine a range of possible failure conditions. While the models proposed offer major insights into potential failure mechanisms, we will demonstrate that deterministic analyses are of limited usefulness because many of the model parameters, such as cohesion, internal friction and pore pressure, are very poorly constrained. This creates problems of non-uniqueness in the solution. An alternative approach involves a series of Monte Carlo simulations to identify potential combinations of parameters that will produce the observed failure plane. Initial input ranges are specified for each parameter and the predetermined model is run repeatedly, with the parameter values for each model selected at random from within the input ranges. The interaction between parameters can be examined in detail, providing a better understanding of the potential failure conditions. This approach, which has been tested initially on a theoretical slope with predetermined failure conditions, highlights the fact that it is impossible to generate a unique model that fits the data when the slope has poorly defined strength parameters. This has clear implications for the validity of commonly used deterministic approaches. This probabilistic back analysis approach has been used to reanalyse the conditions that led to the May 18 collapse on Mount St Helens. Donnadieu, F., Merle, O., and Besson, J.C., 2001, Volcanic edifice stability during cryptodome intrusion, Bulletin of Volcanology, vol 63, p61-72. Voight, B., Janda, R.J., Glicken, H., and Douglass, P.M., 1983, Nature and Mechanics of the Mount St-Helens Rockslide-Avalanche of 18 May 1980, Geotechnique, vol 33, p243-273.

  20. Large slope instabilities in Northern Chile and Southern Peru

    Science.gov (United States)

    Crosta, Giovanni B.; Hermanns, Reginald L.; Valbuzzi, Elena; Frattini, Paolo; Valagussa, Andrea

    2014-05-01

    Deep canyon incision into Tertiary paleosurfaces and large slope instabilities along the canyon flanks characterize the landscape of western slope of the Andes of northern Chile and South Peru. This area belongs to the Coastal Escarpment and Precordillera and is formed by coarse-grained clastic and volcanoclastic formations. The area is characterized by intense seismicity and long-term hyperaridity (Atacama Desert). Landslides along the canyon flanks affect volumes generally up to 1 km3 and locally evolved in large rock avalanches. We prepared a landslide inventory covering an area of about 30,000 km2, extending from Iquique (Chile) to the South and Tacna (Peru) to the North. A total of 606 landslides have been mapped in the area by use of satellite images and direct field surveys, prevalently including large phenomena. The landslides range from 1 10-3 km2 to 464 km2 (Lluta landslide). The total landslide area, inclusive of the landslide scarp and of the deposit, amounts to about 2,130 km2 (about 7% of the area). The mega landslides can be classified as large block slides that can evolve in large rock avalanches (e.g. Minimini landslide). Their initiation seems to be strongly associated to the presence of secondary faults and large fractures transversal to the slope. These landslides show evidence suggesting a re-incision by the main canyon network. This seems particularly true for the Lluta collapse where the main 'landslide' mass is masked or deleted by the successive erosion. Other landslides have been mapped along the Coastal Escarpment and some of the major tectonic escarpments with an E-W trend. We examined area-frequency distributions of landslides by developing logarithmically binned, non-cumulative size frequency distributions that report frequency density as a function of landslide planar area A. The size frequency distribution presents a strong undersampling for smaller landslides, due to the extremely old age of the inventory. For landslides larger than 2 000 m2, the distribution exhibits a power-law behaviour with scaling exponent, β, equal to -2.24. For comparison, we analysed the power-law behaviour of other earthquake-induced landslide inventories, obtaining similar results, although the geological and seismic conditions may have been very different (Buller, New Zealand, β = -2.42; Iningahua, New Zealand, β = -2.53; Northridge, USA, β = -2.39; Chi-Chi, Taiwan, β = -2.30; Wenchuan Earthquake, China, β = -2.19). Volume estimates and slope stability modelling have been completed to characterize the phenomena and the possible triggering mechanisms. For volume estimate, we reconstructed the pre-failure surface for tens of landslides, in order to characterize the area-volume relationship. By using this relationship, we assigned a volume to all landslides of the inventory. The study area is subject to a high seismicity associated to earthquakes of different type: interplate (superficial and intermediate depth), subduction zone earthquakes, and earthquake along the Coastal Escarpment. By analysing the frequency size relationships for earthquake-induced landslides from literature, it is possible to observe that the higher the earthquake Magnitude, the higher the frequency density curve. To quantify this observation, we used the power-law relationships derived for each inventory to calculate the frequency density associated to selected areas, and we plotted these frequencies as a function of the magnitude of the respective earthquakes. By fitting these values, we derived the expected Magnitude required to generate the landslide distribution of the study area. In conclusion, we argue that the evolution of these landslides is controlled by: deep valley incision, canyon walls undercutting and lateral migration of the river controlled by valley flank instabilities, the Presence of weak lithologies and weak basal layers, the river incision debuttressing the slope toe and especially brings to daylighting the weak basal layers observed at some landslide sites, the possible deep groundwater flow above the deep impermeable formations and clay layers, the movement along sub-horizontal basal shear zones which can be locally extruded at the slope toe, the river damming because of the strong lateral components of displacement and successive reincision by the river with dam failure, the possible sequence of reactivations by reincision of the deposit, and the occurrence of high magnitude (8-9) earthquakes.

  1. Soils of sinkholes: effects of slope aspect and lateral transport of sediments on soil variation

    Science.gov (United States)

    Smirnova, Maria; Tsibart, Anna; Abramova, Anna; Koshovskii, Timur; Gennadiev, Alexander

    2015-04-01

    Karst landscapes are highly fragile and particularly vulnerable to subsidence and soil erosion. In karst region there may be hundreds or even thousands of sinkholes and other karst landforms in a small area so that the flat surface is actually absent. The effect of slope aspect on karst landscapes are resulted in different amount of solar radiation and increase of moisture along slopes. In European Russia semiarid landscapes the wind transport of the snow resulted in addition moistening of the soil situated on the eastern slope of depressions. Our research is devoted to the investigation of soil catenas on the slopes of subsidence sinkhole in "Bogdo-Baskuntschak" natural reserve (semiarid landscape). It based on field research of 4 soil catenas situated on the slopes of eastern, northern, western and south exposures. The profile of the sinkhole is an inverted cone (elongated from west to east), slope length varies from 8 to 12 meters, slope gradient - between 40-55% (eastern slope is the shortest and steepest). The short slope length and soil diversity that the sinkholes provided are beneficial for investigation of slope aspect and effect of lateral transport on soil formation. The main feature of sinkhole soil cover is a considerable variety and their high complexity. The lateral transport of sediments resulted in dramatic changes of soil within catenas. Haplic calcisols and arenosols calcaric, situated on the inter-sinkhole flat surface and upper parts of the slopes are substituted by cambisols and leptosols in the middle part of the slopes and colluvic regosols humic in the lower part of the slopes and sinkhole bottom. Soil formation and accumulation of sediments occur simultaneously and lead to the weak soil formation at the middle and lower sections of sinkhole side slopes. The thickness of humus horizon increases from the top to the bottom of sinkhole notably - from 8-12 cm on the upper and middle part of the slopes to 240 cm on the bottom of the sinkhole. The addition moistening of the soil situated on the eastern slope resulted in carbonate leaching from the soil profile. Thus the spatial heterogeneity of soil moisture within sinkhole leads to the replacement of calcareous soil, situated on the of northern, western and south slope exposures by noncalcareous soil of eastern slope. This research was supported by the Russian Foundation for Basic Research (project ? 14-05-31507)

  2. Experimental study on slope sliding and debris flow evolution with and without barrier

    Directory of Open Access Journals (Sweden)

    Ji-kun ZHAO

    2015-01-01

    Full Text Available A constitutive model on the evolution of debris flow with and without a barrier was established based on the theory of the Bingham model. A certain area of the Laoshan Mountain in Nanjing, Jiangsu Province, in China was chosen for experimental study, and the slope sliding and debris flow detection system was utilized. The change curve of the soil moisture content was attained, demonstrating that the moisture content of the shallow soil layer increases faster than that of the deep soil layer, and that the growth rate of the soil moisture content of the steep slope is large under the first weak rainfall, and that of the gentle slope is significantly affected by the second heavy rainfall. For the steep slope, slope sliding first occurs on the upper slope surface under heavy rainfall and further develops along the top platform and lower slope surface, while under weak rainfall the soil moisture content at the lower part of the slope first increases because of the high runoff velocity, meaning that failure occurring there is more serious. When a barrier was placed at a high position on a slope, debris flow was separated and distributed early and had less ability to carry solids, and the variation of the greatest depth of erosion pits on soil slopes was not significant.

  3. Short-term vegetation recovery after a spring grassland fire in Lithuania. Effect of time and slope position

    Directory of Open Access Journals (Sweden)

    P. Pereira

    2013-01-01

    Full Text Available The aim of this work is study the effects of a grassland fire in vegetation recuperation according to fire severity, slope exposition and position. We designed two experimental plots, one located in an east faced slope (Slope A and other in a west faced (Slope B. Vegetation recuperation was assessed 10, 17, 31 and 46 days after the fire. The results showed that fire severity was higher in slope B, than in slope A. In both slopes vegetation recuperation was different according position. Bottom positions recovered faster than slope and upslope positions, that it is attributed to fire severity (higher in slope and upslope areas and ash and soil transport and deposition in bottom areas. The vegetation recuperated faster in slope B and 46 days after the fire, 100% of the plot was covered. This was attributed to higher severity, more complex topography, and inclination of Slope A, that delayed the vegetation recover.

  4. The slope-background for the near-peak regimen of photoemission spectra

    International Nuclear Information System (INIS)

    Highlights: •We propose a method that accounts for the change in the background slope of XPS data. •The slope-background can be derived from Tougaard–Sigmund's transport theory. •The total background is composed by Shirley–Sherwood and Tougaard type backgrounds. •The slope-background employs one parameter that can be related to REELS spectra. •The slope, in conjunction with the Shirley–Sherwood background, provides better fits. -- Abstract: Photoemission data typically exhibits a change on the intensity of the background between the two sides of the peaks. This step is usually very well reproduced by the Shirley–Sherwood background. Yet, the change on the slope of the background in the near-peak regime, although usually present, is not always as obvious to the eye. However, the intensity of the background signal associated with the evolution of its slope can be appreciable. The slope-background is designed to empirically reproduce the change on the slope. Resembling the non-iterative Shirley method, the proposed functional form relates the slope of the background to the integrated signal at higher electron kinetic energies. This form can be predicted under Tougaard–Sigmund's electron transport theory in the near-peak regime. To reproduce both the step and slope changes on the background, it is necessary to employ the slope-background in conjunction with the Shirley–Sherwood background under the active-background method. As it is shown for a series of materials, the application of the slope-background provides excellent fits, is transparent to the operator, and is much more independent of the fitting range than other background methods. The total area assessed through the combination of the slope and the Shirley–Sherwood backgrounds is larger than when only the Shirley–Sherwood background is employed, and smaller than when the Tougaard background is employed

  5. The slope-background for the near-peak regimen of photoemission spectra

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Gomez, A., E-mail: aherrera@qro.cinvestav.mx [CINVESTAV-Unidad Queretaro, Queretaro 76230 (Mexico); Bravo-Sanchez, M. [CINVESTAV-Unidad Queretaro, Queretaro 76230 (Mexico); Aguirre-Tostado, F.S. [Centro de Investigación en Materiales Avanzados, Chihuahua, Chihuahua 31109 (Mexico); Vazquez-Lepe, M.O. [Departamento de Ingeniería de Proyectos, Universidad de Guadalajara, Jalisco 44430 (Mexico)

    2013-08-15

    Highlights: •We propose a method that accounts for the change in the background slope of XPS data. •The slope-background can be derived from Tougaard–Sigmund's transport theory. •The total background is composed by Shirley–Sherwood and Tougaard type backgrounds. •The slope-background employs one parameter that can be related to REELS spectra. •The slope, in conjunction with the Shirley–Sherwood background, provides better fits. -- Abstract: Photoemission data typically exhibits a change on the intensity of the background between the two sides of the peaks. This step is usually very well reproduced by the Shirley–Sherwood background. Yet, the change on the slope of the background in the near-peak regime, although usually present, is not always as obvious to the eye. However, the intensity of the background signal associated with the evolution of its slope can be appreciable. The slope-background is designed to empirically reproduce the change on the slope. Resembling the non-iterative Shirley method, the proposed functional form relates the slope of the background to the integrated signal at higher electron kinetic energies. This form can be predicted under Tougaard–Sigmund's electron transport theory in the near-peak regime. To reproduce both the step and slope changes on the background, it is necessary to employ the slope-background in conjunction with the Shirley–Sherwood background under the active-background method. As it is shown for a series of materials, the application of the slope-background provides excellent fits, is transparent to the operator, and is much more independent of the fitting range than other background methods. The total area assessed through the combination of the slope and the Shirley–Sherwood backgrounds is larger than when only the Shirley–Sherwood background is employed, and smaller than when the Tougaard background is employed.

  6. Small slope tilts caused by meteorological effects and vital processes of trees on a wooded slope in Hidegvíz Valley, Hungary

    Science.gov (United States)

    Mentes, Gyula; Bódis, Virág Bereniké; Vig, Péter

    2014-02-01

    Long-term measurements were carried out to investigate the relationship between ground tilts and variations of meteorological (temperature, precipitation) and hydrological (soil moisture content) parameters in the area of the Sopron Mountains, on a wooded slope of the Hidegvíz Valley, Hungary. The connection between surface tilts and the vital processes of the trees was also studied on the basis of the reference evapotranspiration calculated for the study area. Long- and short-term variations were separated. A long-term ground temperature change of 1 °C caused a 4 ?rad tilt in the SE direction. Short-term temperature effects can be neglected. The fluctuation of temperature around the freezing point caused tilts of about 10 ?rad °C- 1. The soil water content variation had the largest effect on the ground tilt (0.5 ?rad mm- 1). Its contribution to the total ground tilt in the investigated period was about 70 ?rad (65% of the total tilt of 107 ?rad) toward the SSE. The contribution of the wind speed to the ground tilt was about 20 ?rad m s- 1 toward the SSE depending on the water content of the soil. The wind did not cause a permanent ground tilt. The magnitude of the daily tilt variations in the active growing period of trees, from March to October, is 1-2 ?rad while in the dormant period (with no canopy) the tilt variations were less than 0.4 ?rad. The admittances between the evapotranspiration and the ground tilts were 0.3-0.5 ?rad mm- 1 and 0.1-0.2 ?rad mm- 1 in the active and dormant period of the trees, respectively. These small effects superimposed on each other can significantly contribute to slope failures. The results of this study provide information which can be useful in the modelling of landslide movements and for the mitigation of landslide hazards.

  7. Effect of table top slope and height on body posture and muscular activity pattern.

    Science.gov (United States)

    Hassaïne, M; Hamaoui, A; Zanone, P-G

    2015-04-01

    The objective of this study was to assess the effect of table top slope and height on body posture and muscular activity pattern. Twelve asymptomatic participants performed a 5-min reading task while sitting, in six experimental conditions manipulating the table top slope (20° backward slope, no slope) and its height (low, medium, up). EMGs recordings were taken on 9 superficial muscles located at the trunk and shoulder level, and the angular positions of the head, trunk and pelvis were assessed using an inertial orientation system. Results revealed that the sloping table top was associated with a higher activity of deltoideus pars clavicularis (P<0.05) and a smaller flexion angle of the head (P<0.05). A tentative conclusion is that a sloping table top induces a more erect posture of the head and the neck, but entails an overload of the shoulder, which might be harmful on the long run. PMID:25267452

  8. Differentiation of disease recurrence in various primary malignancies using CEA slope analysis.

    Science.gov (United States)

    Staab, H J; Brümmendorf, T; Anderer, F A; Hornung, A; Ahlemann, L M; Kieninger, G

    1985-01-01

    CEA slope analysis was performed for patients with various primary malignancies who developed recurrent disease. In 340 cases CEA slopes could be calculated, and in 289 cases correlated with distinct diagnosis of recurrent disease. Local recurrence showed a slope range of 0.02-15.2 micrograms CEA increase/l serum/10 days (median = 0.28) and metastatic spread a slope range of 0.03-456 micrograms CEA increase/l serum/10 days (median = 0.98). Subgroups of patients with metastatic spread to the liver, bone, peritoneum and other sites had distinct CEA slope distributions independent of the primary tumors. Comparable slope ranges were found with two different commercially available kits, one a radioimmunoassay (antiserum) and the other enzyme-immunoassay (monoclonal antibody). PMID:3901225

  9. DEVELOPMENT OF SHALLOW VISCOUS OIL RESERVES IN NORTH SLOPE

    Energy Technology Data Exchange (ETDEWEB)

    Kishore K. Mohanty

    2004-12-01

    North Slope of Alaska has huge oil deposits in heavy oil reservoirs such as Ugnu, West Sak and Shrader Bluff etc. The viscosity of the last two reservoir oils vary from {approx}30 cp to {approx}3000 cp and the amount in the range of 10-20 billion barrels. High oil viscosity and low formation strength impose problems to high recovery and well productivity. Water-alternate-gas injection processes can be effective for the lower viscosity end of these deposits in West Sak and Shrader Bluff. Several gas streams are available in the North Slope containing NGL and CO{sub 2} (a greenhouse gas). The goal of this research is to develop tools to find optimum solvent, injection schedule and well-architecture for a WAG process in North Slope shallow sand viscous oil reservoirs. Coreflood, quarter 5-spot study, compositional simulation, wettability, relative permeability study and streamline-based simulation were conducted in this project. 1D compositional simulation results agree reasonably well with those of the slim tube experiments. Injection of CO{sub 2}-NGL is preferable over that of PBG-NGL. MME is sensitive to pressure (in the range of 1300-1800 psi) for the injection of PBG-NGL, but not for CO{sub 2}-NGL. Three hydrocarbon phases form in this pressure range. As the mean thickness of the adsorbed organic layer on minerals increases, the oil-water contact angle increases. The adsorbed organic films left behind after extraction of oil by common aromatic solvents used in core studies, such as toluene and decalin, are thinner than those left behind by non-aromatic solvents, such as cyclohexane. The force of adhesion for minerals aged with just the asphaltene fraction is similar to that of the whole oil implying that asphaltenes are responsible for the mixed-wettability in this reservoir. A new relative permeability model for a four-phase, mixed-wet system has been proposed. A streamline module is developed which can be incorporated in an existing finite-difference based compositional simulator to model water flood, gas flood and WAG flood. Horizontal wells increase well deliverability over vertical wells, but sweep efficiency can decrease. The well performance depends on the well length, position, heterogeneity, and viscosity ratio. The productivity increase due to electromagnetic heating is a function of power intensity, flow rate, and frequency etc. The productivity of a well can be doubled by electromagnetic heating. A high-pressure quarter 5-spot model has been constructed to evaluate the sweep efficiency of miscible WAG floods. WAG displacement reduces bypassing compared to gas floods and improves oil recovery in cores. As the WAG ratio decreased and slug size increased, oil recovery increased. Oil was recovered faster with increased slug size and decreased WAG ratio in the simulations for field cases studied.

  10. Research activities on submarine landslides in gentle continental slope

    Science.gov (United States)

    Morita, S.; Goto, S.; Miyata, Y.; Nakamura, Y.; Kitahara, Y.; Yamada, Y.

    2013-12-01

    In the north Sanrikuoki Basin off Shimokita Peninsula, NE Japan, a great number of buried large slump deposits have been identified in the Pliocene and younger formations. The basin has formed in a very gentle continental slope of less than one degree in gradient and is composed of well-stratified formations which basically parallel to the present seafloor. This indicates that the slumping have also occurred in such very gentle slope angle. The slump units and their slip surfaces have very simple and clear characteristics, such as layer-parallel slip on the gentle slope, regularly imbricated internal structure, block-supported with little matrix structure, widespread dewatering structure, and low-amplitude slip surface layer. We recognize that the large slump deposits group of layer-parallel slip in this area is an appropriate target to determine 'mechanism of submarine landslides', that is one of the subjects on the new IODP science plan for 2013 and beyond. So, we started some research activities to examine the feasibility of the future scientific drilling. The slump deposits were recognized basically by 3D seismic analysis. Further detailed seismic analysis using 2D seismic data in wider area of the basin is being performed for better understanding of geologic structure of the sedimentary basin and the slump deposits. This will be good source to extract suitable locations for drill sites. Typical seismic features and some other previous studies imply that the formation fluid in this study area is strongly related to natural gas, of which condition is strongly affected by temperature. So, detailed heat flow measurements was performed in the study area in 2013. For that purpose, a long-term water temperature monitoring system was deployed on the seafloor in October, 2012. The collected water temperature variation is applied to precise correction of heat flow values. Vitrinite reflectance analysis is also being carried out using sediments samples recovered by IODP Expedition 337, which is conducted in a part of the study area from July through September in 2012. The values of vitrinite reflectance will be available for modeling thermal history in the sedimentary basin. A science meeting and a field trip were held in Miyazaki Prefecture in September , 2012. At the field trip, we observed typical geologic structures related to slumping and dewatering in Nichinan Group, which are good onshore objects so as to share the aspects of the slump deposits in the Sanrikuoki Basin among the community. This occasion is aimed at sharing better scientific understanding on slumping and related dewatering and also at identifying the issues for planning the scientific drilling. This study uses the 3D seismic data from the METI seismic survey 'Sanrikuoki 3D' in 2008. The seismic analysis, the vitrinite reflectance analysis, and the science meeting and the field excursion in Miyazaki were supported by the foundation of feasibility studies for future IODP scientific drillings by JAMSTEC CDEX in 2012-2013.

  11. Landslide trigger factors on populated, unstable slopes, Tusion, Tajikistan.

    Science.gov (United States)

    Domej, Gisela

    2015-04-01

    The Pamir region close to the Tajik-Afghan border is regularly affected by severe landslides threatening local population, their livelihood and infrastructure. In addition to landslides appearing as immediate consequence of earthquake, a high number of ground movements without previous seismic activity are also observed. The number of reported events and problem areas has strongly increased within the last ten to fifteen years. Consequently, a study was conducted to determine the triggering factors of these landslides without seismic cause. For accessibility reasons, the community of Tusion, southeast of Khorog, Gorno-Badakhshan, southern Tajikistan, where the capital township is located on a slowly moving slope, was chosen for the pilot project, and geologic mapping as well as seismic refraction and Schlumberger geoelectrics were applied. The geologic survey showed that the valley flanks around Tusion are covered with large amounts of postglacial and fluvial debris as well as moraine deposits. The absence of glacial ice and the retreat of remaining glaciers caused unstable valley flanks at many sites and, in consequence, extensive gravitational mass movements in the past, which are responsible for the today's layered ground structure as well as many secondary slumps. The latter often damage irrigation lines, which tends to further destabilize the slope. To obtain an accurate image of the superposed layers, the geophysical survey was conducted on three inhabited flanks. Arguments in favour for those three locations were not only the possibility of direct risk estimation for the region, but also the fact that the number of landslides increases constantly with population growth. Seismic and electric methods were applied in parallel to distinguish soil types and structural properties as well as to estimate the degree of water saturation. Despite of the methods' simplicity, they revealed precise explanations on triggering factors of landslides. The geophysical survey showed different density and electric conductivity regimes in the upper layers resulting from exposure and decomposition during the last centuries and especially from uncontrolled irrigation since the 1990s. The electric prospection showed a high water saturation in the weathering layers which is explained on one hand by a higher porosity of the material close to the surface, and on the other hand by the fact that crystalline rocks decompose to clay which, in turn, is able to take up water. Almost all landslides start in a depth where surveys show firstly a rapid decrease of water saturation, and secondly a transition to more compact material. Thus, it can be concluded that decomposition and irrigation provoke a (re-)activation of sliding surfaces inside the postglacial debris body. The upper layers slide on a humid surface and create the frequently observed landslides in inhabited areas.

  12. Deformation monitoring and modeling based on LiDAR data for slope stability assessment

    OpenAIRE

    Hu, Hui

    2013-01-01

    Time dependent deformation is a common process in soil slopes but never the less a challenging task for stability assessment. Slope failure and the land subsidence originating not only from extensive constructions and mining but also due to geological processes are common problems, which adversely influence environment, human safety and economic development. In order to pursue an advanced methodology for management and mitigation of soil slope failure, such points as adequate monitoring techn...

  13. Mass-movement, geologic structure and morphologic evolution of the Pizzotto Greci slope (Calabria, Italy)

    Science.gov (United States)

    Sorriso-Valvo, Marino; Gullà, Giovanni; Antronico, Loredana; Tansi, Carlo; Amelio, Maria

    1999-10-01

    Deep-seated mass-movements of different types affect the Pizzotto-Greci slope in northwest Calabria, Italy. The slope is carved out of phyllitic rocks capped by gneissic layers. Its geological structure is extremely complicated by tectonic structures that pervasively cross the slope transversely and downslope. A large-scale gravitational deformation of sackung type affects the slope. On the upslope side a debris-flow source area feeds a large fan constructed by recurrent debris-flow deposits. Aggradation is consequently occurring along the stream at the base of the slope. In order to define the internal structure of the slope for a stability slope model, geological, geostructural, geomorphological, historical and dendrogeomorphologic studies, as well as direct geotechnical logs and indirect geophysical investigations have been carried out over a two-year project financed by the EC Environment Programme. The main aspects of the geological and geomorphological studies and some preliminary geotechnical data are presented here, along with a conceptual model aimed at describing the relationships between the mass-movements on the slope and the construction/destruction stages of the fan at the base of the slope. The model is based on the assumption that aggradation has a stabilising effect on the slope, thus debris-flow activity is reduced and, consequently, destruction of the fan occurs, bringing the slope again towards unstable conditions. The reactivation of mass-movement, however, leads to the reconstruction of the fan and the buttressing effect at the base of the slope is restored. Thus, the process is cyclic and self-regulating.

  14. Slope streaks on Mars: Correlations with surface properties and the potential role of water

    OpenAIRE

    Schorghofer, N.; Aharonson , O.; Khatiwala, S.

    2002-01-01

    The Mars Orbiter Camera on board the Mars Global Surveyor spacecraft has returned images of numerous dark streaks that are the result of down-slope mass movement occurring under present-day martian climatic conditions. We systematically analyze over 23,000 high-resolution images and demonstrate that slope streaks form exclusively in regions of low thermal inertia (confirming earlier results), steep slopes, and, remarkably, only where peak temperatures exceed 275 K. The northernmost streaks, w...

  15. Slope shape effect on runoff and soil erosion under natural rainfall conditions

    OpenAIRE

    Sensoy H; Kara

    2014-01-01

    Slope is often non-uniform along the hillslope, with variations describing concave and convex shapes associated with natural hillslopes. This is because runoff generations vary significantly over short distances, with changes in surface alteration during or between flow events on different slope shapes. The aim of this research is to determine the effects of slope shapes on runoff and soil erosion. A field experiment was conducted from September 2007 to September 2009 on hillside field plots ...

  16. Halocline water modification and along-slope advection at the Laptev Sea continental margin

    OpenAIRE

    Bauch, D; Torres-Valdes, S.; Polyakov, I; Novikhin, A.; I. Dmitrenko; Mckay, J; Mix, A.

    2014-01-01

    A general pattern in water mass distribution and potential shelf–basin exchange is revealed at the Laptev Sea continental slope based on hydrochemical and stable oxygen isotope data from the summers 2005–2009. Despite considerable interannual variations, a frontal system can be inferred between shelf, continental slope and central Eurasian Basin waters in the upper 100 m of the water column along the continental slope. Net sea-ice melt is consistently found at the continenta...

  17. Laboratory and 3-D-distinct element analysis of failure mechanism of slope under external surcharge

    OpenAIRE

    Li, N.; Cheng, Y.M.

    2014-01-01

    Landslide is a major disaster resulting in considerable loss of human lives and property damages in hilly terrain in Hong Kong, China and many other countries. The factor of safety and the critical slip surface for slope stabilization are the main considerations for slope stability analysis in the past, while the detailed post-failure conditions of the slopes have not been considered in sufficient details. There are however increasing interest on the consequences af...

  18. Maximum-Entropy Method for Evaluating the Slope Stability of Earth Dams

    OpenAIRE

    Shuai Wang; Wei Wang; Chuanqi Li

    2012-01-01

    The slope stability is a very important problem in geotechnical engineering. This paper presents an approach for slope reliability analysis based on the maximum-entropy method. The key idea is to implement the maximum entropy principle in estimating the probability density function. The performance function is formulated by the Simplified Bishop’s method to estimate the slope failure probability. The maximum-entropy method is used to estimate the probability density function (PDF) of the perf...

  19. Slope analysis for elastic proton-proton and proton-antiproton scattering

    OpenAIRE

    Okorokov, V. A.

    2008-01-01

    The diffraction slope parameter is investigated for elastic proton-proton and proton-antiproton scattering based on the all available experimental data at intermediate square of momentum transfer in the main. Energy dependence of the elastic diffraction slope is approximated by various analytic functions in a model-independent fashion. The expanded standard logarithmic approximations allow to describe experimental slopes in all available energy range at qualitative level reasonably. Various f...

  20. Diffraction slopes for elastic proton-proton and proton-antiproton scattering

    OpenAIRE

    Okorokov, V. A.

    2008-01-01

    The diffraction slope parameter is investigated for elastic proton-proton and proton-antiproton scattering based on the all available experimental data at low momentum transfer values. Energy dependence of the elastic diffraction slopes is approximated by various analytic functions. The expanded "standard" logarithmic approximations allow to describe experimental slopes in all available energy range reasonably. Various approximations differ from each other both in the low energy and very high...

  1. Slope instabilities on perennially frozen and glacierised rock walls: multi-scale observations, analyses and modelling

    OpenAIRE

    Fischer, L

    2009-01-01

    Slope failures from steep bedrock slopes have occurred in mountain areas throughout time. This is a consequence of the topography, geological characteristics, intense freeze-thaw activity and oversteepened slopes from glacier erosion. However, during the past decades, an increased number of periglacial rock avalanche events have been recorded in the European Alps and other high mountain ranges which are thought to be related to permafrost degradation and glacier shrinkage, indi...

  2. The evolution of the slope breaks in Qiongdongnan Basin and their controlling factors

    Science.gov (United States)

    Liu, Jianbao; Sun, Zhen; Wang, Zhenfeng; Sun, Zhipeng; Wang, Zhangwen; Zhao, Zhongxian; Liu, Siqing

    2015-09-01

    Qiongdongnan Basin (QB) experienced three main tectonic stages in the Cenozoic: rifting, thermal subsidence, and accelerated subsidence. Corresponding to these stages, the slope breaks also underwent three different evolutionary stages, which differed in space and time between the east and west of QB. Structural slope breaks developed during the rifting stage in the Paleocene. Transitional sedimentary strata without obvious slope break developed in the neritic environment during the thermal subsidence stage in the Neocene. Sedimentary slope breaks and gentle slope zone without slope break developed during the accelerated subsidence stage. The sedimentary slope breaks could be further classified into progradational and aggradational types, the starting points of which varied in space and time. Spatially, the progradational sequences in the Ledong and Lingshui sags started at the north of today's deep central basin, distant from the basin edge. In the Songnan and Baodao sags, the aggradational sequences were close to the sag edge and essentially controlled by the underlying major boundary faults. Temporally, sedimentary slope breaks developed early in the east and late in the west and were initially partitioned and eventually unified. Fault activity controlled the types and ending time of structural slope breaks during the rifting stage, while tectonic subsidence controlled the time and places of progradational slope breaks during the accelerated subsidence stage. Sediment supply controlled the superposition patterns of the sedimentary sequences of the sedimentary slope breaks. It is suggested that the evolutionary history of the slope breaks has been primarily affected by the southward transition of the South China Sea ocean ridge, the westward collision of the Philippine Sea Plate, and the dextral strike-slipping of the Red River Fault.

  3. Problems of definitive slopes mining at Doly Nástup Tušimice

    OpenAIRE

    Martin Vrubel; Dana Sládková

    2007-01-01

    The instability of slopes influents mining business in many aspects at opencast mining. The temporary decrease of intended mined volumes due to landslips is common and sometimes there is necessary to change origin-mining plans. It has impact to economy and other essential costs for rehabilitation are required. In case of definitive slopes formation in contact to traffic and communication networks, watercourses and infrastructures of seats stability of slope security there is even more importa...

  4. Study of Real-Time Slope Stability Monitoring System Using Wireless Sensor Network(WSN)

    OpenAIRE

    Dave Ta Teh Chang; Yuh-Show Tsai; Kai-Chun Yang

    2013-01-01

    Traditional monitoring instruments have been found difficult to meet the requirement for real-time monitoring. This study applied Wireless Sensor Network (WSN) to slope stability monitoring, In recent years, the slopes in Taiwan have frequently caused disasters after heavy rains, and traand understand the process of slope instability from the characterization variation of new concepts. In the first stage, the Mems Sensors were selected and calibrated, and the accuracy was selected as 0.1 ?...

  5. Recent and future warm extreme events and high-mountain slope stability

    OpenAIRE

    Huggel, C.; Salzmann, Nadine; Allen, S; Caplan-Auerbach, J; Fischer, L; Haeberli, W.; Larsen, C; Schneider, D; Wessels, R.

    2010-01-01

    The number of large slope failures in some high-mountain regions such as the European Alps has increased during the past two to three decades. There is concern that recent climate change is driving this increase in slope failures, thus possibly further exacerbating the hazard in the future. Although the effects of a gradual temperature rise on glaciers and permafrost have been extensively studied, the impacts of short-term, unusually warm temperature increases on slope stability in high mount...

  6. Asynchronism effect of cell population on the initial slope of dose-effect curve

    International Nuclear Information System (INIS)

    The presence of the initial slope both for survival and dose curves and mutation inductions under the effect of various radiation types, is proved. It is established that the initial slope of the survival curve is proportional to the dose in all types of ionizing radiations, and its value changes regularly depending on the cell position in the cycle. In the case of asynchronous cell population, the initial slope of the survival curve can be determined by the most sensitive cells. The estimation of the value of this slope by studying cell survival can be rather difficult

  7. Efficiency of Timber Jack 450C with Different Loading Volumes in Different Slopes

    Directory of Open Access Journals (Sweden)

    Majid Lotfalian

    2007-01-01

    Full Text Available Primary transportation is an upper time, expensive and hard labour. The most skidding are with using of rubber wheel of Timber jack 450C in Iran country that has devoted 60% of utilization expenses. In order to, investigate of slope and loading volume effects on time of loaded traveling had used time study for Timberjack 450C. In one of strip roads in parcel eleven of district two of Langa management plan forest (Kelardasht region in North of Iran determined 5 and 3 different slopes classes and volumes classes, respectively. Then, time study was performed in slope classes with different loading volume in downward skidding. The first, collection of data have noted in special form and then have converted to uniform unit of m sec-1. Descriptive statistics for each data set were calculated using the SPSS software. With presupposition that loading volume and slope are effective on the obtained time, these parameters have analyzed. ANOVA and Tukey test were used for loading volume factor. For investigation slope factor had used of Mann Whitney non-parametric test in order to comparison of loaded traveling speed in different slopes. Results of present research had showed that influence of loading volume on the loaded traveling time is insignificant, but loaded traveling speed in different slope classes is significant (in slopes >30% as, speed of skidder machine is decreased with increase of slope variable.

  8. Efficiency of Timber Jack 450C with different loading volumes in different slopes.

    Science.gov (United States)

    Lotfalian, Majid; Daliri, Hasan Sam; Kooch, Yahya

    2007-10-15

    Primary transportation is an upper time, expensive and hard labour. The most skidding are with using of rubber wheel of Timber jack 450C in Iran country that has devoted 60% of utilization expenses. In order to, investigate of slope and loading volume effects on time of loaded traveling had used time study for Timberjack 450C. In one of strip roads in parcel eleven of district two of Langa management plan forest (Kelardasht region in North of Iran) determined 5 and 3 different slopes classes and volumes classes, respectively. Then, time study was performed in slope classes with different loading volume in downward skidding. The first, collection of data have noted in special form and then have converted to uniform unit of m sec(-1). Descriptive statistics for each data set were calculated using the SPSS software. With presupposition that loading volume and slope are effective on the obtained time, these parameters have analyzed. ANOVA and Tukey test were used for loading volume factor. For investigation slope factor had used of Mann Whitney non-parametric test in order to comparison of loaded traveling speed in different slopes. Results of present research had showed that influence of loading volume on the loaded traveling time is insignificant, but loaded traveling speed in different slope classes is significant (in slopes >30%) as, speed of skidder machine is decreased with increase of slope variable. PMID:19093479

  9. Earthquake-induced displacement of cohesive-frictional slopes subject to cracks

    Science.gov (United States)

    Abd, A. H.

    2015-09-01

    The upper bound theorem of limit analysis together with Newmark's method are employed to evaluate the displacement of soil slopes subject to cracks. The pseudo static approach has been routinely used in the literature to estimate the seismic displacement of soil slopes. However, the effect of cracks on the slope displacement has yet to be tackled. In this paper, a new technique is proposed to estimate the horizontal displacement at the slope toe due to a given earthquake postulating rough estimation of real time crack formation. Rotational failure mechanisms for intact slopes exhibiting the formation of cracks as part of the failure process and the case of cracks which are pre-existing in the slope were considered. On the basis of Newmark's method, the seismic-induced displacement is calculated by incorporating a stepwise yield acceleration corresponding to the cracks occurring in the slope. Results of the proposed technique can reasonably bridge the gap between the conservatism of assuming the slopes subject to the most detrimental cracks, and the overestimation of slope stability resulted from the neglect of crack formation. An example illustrating the procedure for a given earthquake is presented. Also, charts providing the values needed to calculate the stepwise yield accelerations are proposed.

  10. Failure Modes and Stability of Rock Mass Slope Containing Multi-weak Interlayer

    OpenAIRE

    Liu Jie-Qun; Chen Lu-Wang; Liu Jin-Long

    2013-01-01

    The phenomena of rock mass slope with multi-weak interlayer can be found in real engineering frequently. It is worthy to study the influence of multi-weak interlayer on failure of rock mass slope. Based on the shear strength reduction finite element method, stability and failure surface of rock mass slope with different parameters had been studied, the failure mechanism of rock mass slope containing multi-weak interlayer has been analyzed. It can be found that the stability of consequent rock...

  11. Submarine slope failures along the convergent continental margin of the Middle America Trench

    Science.gov (United States)

    Harders, Rieka; Ranero, CéSar R.; Weinrebe, Wilhelm; Behrmann, Jan H.

    2011-06-01

    We present the first comprehensive study of mass wasting processes in the continental slope of a convergent margin of a subduction zone where tectonic processes are dominated by subduction erosion. We have used multibeam bathymetry along ˜1300 km of the Middle America Trench of the Central America Subduction Zone and deep-towed side-scan sonar data. We found abundant evidence of large-scale slope failures that were mostly previously unmapped. The features are classified into a variety of slope failure types, creating an inventory of 147 slope failure structures. Their type distribution and abundance define a segmentation of the continental slope in six sectors. The segmentation in slope stability processes does not appear to be related to slope preconditioning due to changes in physical properties of sediment, presence/absence of gas hydrates, or apparent changes in the hydrogeological system. The segmentation appears to be better explained by changes in slope preconditioning due to variations in tectonic processes. The region is an optimal setting to study how tectonic processes related to variations in intensity of subduction erosion and changes in relief of the underthrusting plate affect mass wasting processes of the continental slope. The largest slope failures occur offshore Costa Rica. There, subducting ridges and seamounts produce failures with up to hundreds of meters high headwalls, with detachment planes that penetrate deep into the continental margin, in some cases reaching the plate boundary. Offshore northern Costa Rica a smooth oceanic seafloor underthrusts the least disturbed continental slope. Offshore Nicaragua, the ocean plate is ornamented with smaller seamounts and horst and graben topography of variable intensity. Here mass wasting structures are numerous and comparatively smaller, but when combined, they affect a large part of the margin segment. Farther north, offshore El Salvador and Guatemala the downgoing plate has no large seamounts but well-defined horst and graben topography. Off El Salvador slope failure is least developed and mainly occurs in the uppermost continental slope at canyon walls. Off Guatemala mass wasting is abundant and possibly related to normal faulting across the slope. Collapse in the wake of subducting ocean plate topography is a likely failure trigger of slumps. Rapid oversteepening above subducting relief may trigger translational slides in the middle Nicaraguan upper Costa Rican slope. Earthquake shaking may be a trigger, but we interpret that slope failure rate is lower than recurrence time of large earthquakes in the region. Generally, our analysis indicates that the importance of mass wasting processes in the evolution of margins dominated by subduction erosion and its role in sediment dynamics may have been previously underestimated.

  12. Geotechnical characteristics and slope stability on the Ebro margin, western Mediterranean

    Science.gov (United States)

    Baraza, J.; Lee, H.J.; Kayen, R.E.; Hampton, M.A.

    1990-01-01

    Sedimentological and geotechnical analyses of core samples from the Ebro continental slope define two distinct areas on the basis of sediment type, physical properties and geotechnical behavior. The first area is the upper slope area (water depths of 200-500 m), which consists of upper Pleistocene prodeltaic silty clay with a low water content (34% dry weight average), low plasticity, and high overconsolidation near the seafloor. The second area, the middle and lower slope (water depths greater than 500 m), contains clay- and silt-size hemipelagic deposits with a high water content (90% average), high plasticity, and a low to moderate degree of overconsolidation near the sediment surface. Results from geotechnical tests show that the upper slope has a relatively high degree of stability under relatively rapid (undrained) static loading conditions, compared with the middle and lower slopes, which have a higher degree of stability under long-term (drained) static loading conditions. Under cyclic loading, which occurs during earthquakes, the upper slope has a higher degree of stability than the middle and lower slopes. For the surface of the seafloor, calculated critical earthquake accelerations that can trigger slope failures range from 0.73 g on the upper slope to 0.23 g on the lower slope. Sediment buried well below the seafloor may have a critical acceleration as low as 0.09 g on the upper slope and 0.17 g on the lower slope. Seismically induced instability of most of the Ebro slope seems unlikely given that an earthquake shaking of at least intensity VI would be needed, and such strong intensities have never been recorded in the last 70 years. Other cyclic loading events, such as storms or internal waves, do not appear to be direct causes of instability at present. Infrequent, particularly strong earthquakes could cause landslides on the Ebro margin slope. The Columbretes slide on the southwestern Ebro margin may have been caused by intense earthquake shaking associated with volcanic emplacement of the Columbretes Islands. Localized sediment slides on steep canyon and levee slopes could have been caused by less intense shaking. In general, the slope is stable under present environmental loading conditions and is fundamentally constructional. Nevertheless, rapid progradation caused by high sedimentation rates and other processes acting during low sea-level periods, such as more intense wave loading near the shelfbreak, may have caused major instability in the past. ?? 1990.

  13. Bistatic-radar estimation of surface-slope probability distributions with applications to the moon.

    Science.gov (United States)

    Parker, M. N.; Tyler, G. L.

    1973-01-01

    A method for extracting surface-slope frequency distributions from bistatic-radar data has been developed and applied to the lunar surface. Telemetry transmissions from orbiting Apollo spacecraft were received on the earth after reflection from the lunar surface. The echo-frequency spectrum was related analytically to the probability distribution of lunar slopes. Standard regression techniques were used to solve the inverse problem of finding slope distributions from observed echo-frequency spectra. Data taken simultaneously at two wavelengths, 13 and 116 cm, have yielded diverse slope statistics.

  14. Sub-microradian Surface Slope Metrology with the ALS Developmental Long Trace Profiler

    Energy Technology Data Exchange (ETDEWEB)

    Yashchuk, Valeriy V; Barber, Samuel; Domning, Edward E.; Kirschman, Jonathan L.; Morrison, Gregory Y.; Smith, Brian V; Siewert, Frank; Zeschke, Thomas; Geckeler, Ralf; Just, Andreas

    2009-09-11

    A new low budget slope measuring instrument, the Developmental Long Trace Profiler (DLTP), was recently brought to operation at the ALS Optical Metrology Laboratory. The design, instrumental control and data acquisition system, initial alignment and calibration procedures, as well as the developed experimental precautions and procedures are described in detail. The capability of the DLTP to achieve sub-microradian surface slope metrology is verified via cross-comparison measurements with other high performance slope measuring instruments when measuring the same high quality test optics. The directions of future work to develop a surface slope measuring profiler with nano-radian performance are also discussed.

  15. The spatial variance of hill slope erosion in Loess Hilly Area by 137Cs tracing method

    International Nuclear Information System (INIS)

    Based on analysis of 137Cs activities in soil profiles on hill slope of different slope lengths in the Loess Hilly Area in China, the spatial variance of erosion was studied. The results show that the slope length has great impact on the spatial distribution of the soil erosion intensity, and the soil erosion intensity on loess hill slope was in a fluctuating tendency. In the influx process of runoff in a small watershed, net soil loss intensity increased first and then decreased with flow distance. (authors)

  16. Examination of composite enamel layer systems by ion beam slope cutting

    International Nuclear Information System (INIS)

    A non-mechanical, new method of sample preparation - the ion beam slope cutting - is presented. On the basis of a mechanically produced ground plane illustrating the composite enamel interface on an extracted free from caries tooth in usual manner a defined slope is made at an angle of 45 degrees to the interface by means of inert gas ions over a diaphragm. The resulting slope plane is neither mechanically deformed nor directly influenced by ions. First examination results (SEM) allow to draw conclusions about filler construction, defective adhesion and cohesive defects. The ion beam slope cutting is a completion of examination possibilities. (author)

  17. Site Scientist for the North Slope of Alaska Site

    Energy Technology Data Exchange (ETDEWEB)

    Verlinde, Johannes [The Pennyslvania State University

    2016-03-11

    Under this grant our team contributed scientific support to the Department of Energy Atmospheric Radiation Program’s (DOE-ARM) Infrastructure team to maintain high quality research data at the DOE-ARM North Slope of Alaska with special emphasis on the radars. Under our guidance two major field campaigns focusing on mixed-phase Arctic clouds were conducted that greatly increased the community’s understanding of the many processes working together to control the evolution of single-layer cloud mixed-phase clouds. A series of modeling and observational studies revealed that the longevity of the radiatively important liquid phase is strongly dependent on how the ice phase develops in mixed-phase clouds. A new ice microphysics parameterization was developed to capture better the natural evolution of ice particle growth in evolving environments. An ice particle scattering database was developed for all ARM radar frequencies. This database was used in a radar simulator (Doppler spectrum and polarimetric variables) to aid in the interpretation of the advanced ARM radars. At the conclusion of this project our team was poised to develop a complete radar simulator consistent with the new microphysical parameterization, taking advantage of parameterization’s advanced characterization of the ice shape and ice density.

  18. Slope instability related to permafrost changes on Mexican volcanoes

    Science.gov (United States)

    Delgado Granados, Hugo; Molina, Victor Soto

    2015-04-01

    Permafrost is present above 4,500 meters at the three highest Mexican mountains, Citlaltépetl, Popocatépetl and Iztaccihuatl (5,675, 5,452 and 5,286m asl, respectively), all active volcanoes. During the rainy season in the central region of Mexico, the occurrence of small debris-flows in the ice-free parts of the mountains, as well as small lanslides is frequent. At Popocatépetl volcano, flows are mostly related to a combination of the eruptive activity and climatic factors. However, the volcanic activity is different at Citlaltépetl and Iztaccihuatl where there is no eruptive activity, but landslides have occurred in recent years on their steep slopes because its stability has been altered as a result of an increase in the air temperature which in turn has caused variations in the thickness of the active layer of permafrost, causing as a consequence, the increase of an even more unstable soil. Additionally, cracks in the rock walls are subject to an increasing hydrostatic pressure due to continuous daily freezing and thawing of seasonal water produced by a warmer and less solid precipitation accumulating in the cracks over time and in the unconsolidated potentially unstable material.

  19. Commercial possibilities for stranded conventional gas from Alaska's North Slope

    Science.gov (United States)

    Attanasi, E.D.; Freeman, P.A.

    2014-01-01

    Stranded gas resources are defined for this study as gas resources in discrete accumulations that are not currently commercially producible, or producible at full potential, for either physical or economic reasons. Approximately 35 trillion cubic feet (TCF) of stranded gas was identified on Alaska’s North Slope. The commercialization of this resource requires facilities to transport gas to markets where sales revenue will be sufficient to offset the cost of constructing and operating a gas delivery system. With the advent of the shale gas revolution, plans for a gas pipeline to the conterminous US have been shelved (at least temporarily) and the State and resource owners are considering a liquefied natural gas (LNG) export project that targets Asian markets. This paper focuses on competitive conditions for Asian gas import markets by estimating delivered costs of competing supplies from central Asia, Russia, Indonesia, Malaysia, and Australia in the context of a range of import gas demand projections for the period from 2020 to 2040. These suppliers’ costs are based on the cost of developing, producing, and delivering to markets tranches of the nearly 600 TCF of recoverable gas from their own conventional stranded gas fields. The results of these analyses imply that Alaska’s gas exports to Asia will likely encounter substantial competitive challenges. The sustainability of Asia’s oil-indexed LNG pricing is also discussed in light of a potentially intense level of competition.

  20. Estimated prospective tanker rates for Alaska North Slope crude oil

    International Nuclear Information System (INIS)

    Within the next ten years, three significant events will affect the structure of tankering costs for the Alaska North Slope (ANS) oil fields. These are: the double hulling requirement of the Oil Spill Pollution Act of 1990 (OPA90); the ageing of the tanker fleet; and the decline in ANS and West Coast oil production, which will eliminate more costly shipments to the Gulf Coast. The purpose of this paper is to estimate how these will affect tankering costs over the next twenty years. As baseline, the existing fleet is described, followed by a detailed discussion of the above factors. Company specific shipping requirements are calculated as compared to ship-by-ship tonnage availability (based on the current fleet) pursuant to these events, and the resultant tonnage deficit. A model is presented that derives a hypothetical reconstruction scheme to eliminate the deficits on a company specific ship-by-ship basis. The resulting costs are then translated into a weighted average per barrel ANS cost. The specific double hull costs are segregated. (author)

  1. Constraining slope parameter of symmetry energy from nuclear structure

    CERN Document Server

    Inakura, T

    2015-01-01

    Four quantities deducible from nuclear structure experiments have been claimed to correlate to the slope parameter $L$ of the symmetry energy; the neutron skin thickness, the cross section of low-energy dipole (LED) mode, dipole polarizability $\\alpha_D$, and $\\alpha_D S_0$ (i.e. product of $\\alpha_D$ and the symmetry energy $S_0$). By the calculations in the Hartree-Fock plus random-phase approximation with various effective interactions, we compare the correlations between $L$ and these four quantities. The correlation derived from different interactions and the correlation from a class of interactions that are identical in the symmetric matter as well as in $S_0$ are simultaneously examined. These two types of correlations may behave differently, as exemplified in the correlation of $\\alpha_D$ to $L$. It is found that the neutron skin thickness and $\\alpha_DS_0$ correlate well to $L$, and therefore are suitable for narrowing down the value of $L$ via experiments. The LED emergence and upgrowth makes the $\\...

  2. Material-Point-Method Analysis of Collapsing Slopes :

    DEFF Research Database (Denmark)

    Andersen, SØren; Andersen, Lars

    2009-01-01

    To understand the dynamic evolution of landslides and predict their physical extent, a computational model is required that is capable of analysing complex material behaviour as well as large strains and deformations. Here, a model is presented based on the so-called generalised-interpolation material-point method, combining a Eulerian grid for solving the governing equations of a continuum with a Lagrangian description for the material. The method is extended to analyse interaction between multiple bodies, introducing a master-slave algorithm for frictional contact along interfaces. Further, a deformed material description is introduced, based on time integration of the deformation gradient and utilising Gauss quadrature over the volume associated with each material point. The method has been implemented in a Fortran code and employed for the analysis of a landslide that took place during the night of December 1st, 2008, near Lønstrup, Denmark. Using a simple Mohr-Coulomb model for the soil, the computational model is able to reproduce the change in the slope geometry at the site.

  3. Nonlinear Characteristics of Internal Wave Reflection from Sloping Topography

    Science.gov (United States)

    Rodenborn, Bruce; Kiefer, Daniel; Zhang, Hepeng; Swinney, Harry L.

    2008-11-01

    Internal waves are generated in the oceans by surface waves and abyssal tidal flow over the ocean floor. The interaction among these waves and their reflection from the ocean floor are believed to cause mixing necessary to support thermohaline circulation. The reflection of internal waves is often treated as a linear or a weakly nonlinear and inviscid problem, but the full nonlinear effects generate higher harmonics and mixing. We use Particle Image Velocimetry to study the reflection of internal waves from a sloping bottom boundary in a laboratory tank. The experiments are modeled using a 2-D pseudo-spectral numerical simulation that solves the nonlinear problem in the Boussinesq approximation. The kinetic energy density of harmonics generated upon wave reflection from the boundary is examined as a function of the boundary angle and wave angle. Certain harmonics are found to be missing, in accord with recently derived selection rules. [1]W. Munk and C. Wunsch, Deep-Sea Res. I 45, 1977-2010 (1998) [2]T. Dauxois and W.R. Young, J. Fluid Mech. 390, 271-295 (1999), [3] C.H. Jiang and P.J. Marcus, preprint, (2008)

  4. Temperature statistics above a deep-ocean sloping boundary

    CERN Document Server

    Cimatoribus, Andrea A

    2015-01-01

    We present a detailed analysis of the statistics of temperature in an oceanographic observational dataset. The data is collected using a moored array of thermistors, 100m tall and starting 5m above the bottom, deployed during four months above the slopes of a seamount in the North Eastern Atlantic Ocean. Turbulence at this location is strongly affected by the semidiurnal tidal wave. Mean stratification is stable in the entire dataset. We compute structure functions, of order up to 10, of the distributions of temperature increments. Strong intermittency is observed in particular during the downslope phase of the tide, and farther from the solid bottom. In the lower half of the mooring during the upslope phase, the statistics of temperature are consistent with those of a passive scalar. In the upper half of the mooring, the statistics of temperature deviate from those of a passive scalar, and evidence of turbulent convective activity is found. The downslope phase is generally thought to be more shear dominated,...

  5. Evolution of revegetated ski slopes in different environments

    Directory of Open Access Journals (Sweden)

    Argenti G

    2011-12-01

    Full Text Available Revegetation of ski slopes is a useful technique to limit soil erosion, reduce the visual impact of the tracks and lengthen the duration of snow cover. Restoration is often performed with commercial forage mixtures with the aim of creating a fast soil cover, then allowing the natural recolonization of artificial swards in the mid-long term. To investigate on the recolonization dynamics, data were collected from 21 different plots from the Alps and the Apennines (Valtellina, Plan de Corones, Sappada, Cimone. Knowledge of both the original mixtures used for restoration and the timespan since intervention (ranging from 1 to 21 years allowed to throw light on the naturalization process for the studied plots. Ground cover, floristic richness and relative presence of sown and native species were measured along linear transects established on the analyzed ski tracks. Results showed the effectiveness of plant restoration, in terms of soil coverage and (in some cases persistence of species of the original mixtures. Recovery of autochthonous species was strongly affected by site elevation and time elapsed since restoration. Moreover, the distance of ski lanes from forest edges seems to influence the dynamics of recolo­nisation process. Renaturalization was remarkably faster in the lower-altitude Apennine study plot. Application of a regression analysis revealed that elevation and timespan since restoration may be considered useful predictors of the level of naturalization of the restored canopies.

  6. Regional variability of slope stability: Application to the Eel margin, California

    Science.gov (United States)

    Lee, H.; Locat, J.; Dartnell, P.; Israel, K.; Florence, Wong

    1999-01-01

    Relative values of downslope driving forces and sediment resisting forces determine the locations of submarine slope failures. Both of these vary regionally, and their impact can be addressed when the data are organized in a Geographic Information System (GIS). The study area on the continental margin near the Eel River provides an excellent opportunity to apply GIS spatial analysis techniques for evaluation of slope stability. In this area, swath bathymetric mapping shows seafloor morphology and distribution of slope steepness in fine detail, and sediment analysis of over 70 box cores delineates the variability of sediment density near the seafloor surface. Based on the results of ten geotechnical studies of submarine study areas, we developed an algorithm that relates surface sediment density to the shear strength appropriate to the type of cyclic loading produced by an earthquake. Strength and stress normalization procedures provide results that are conceptually independent of subbottom depth. Results at depth are rigorously applicable if sediment lithology does not vary significantly and consolidation state can be estimated. Otherwise, the method applies only to shallow-seated slope failure. Regional density, slope, and level of anticipated seismic shaking information were combined in a GIS framework to yield a map that illustrates the relative stability of slopes in the face of seismically induced failure. When a measure of predicted relative slope stability is draped on an oblique view of swath bathymetry, a variation in this slope stability is observed on an otherwise smooth slope along the mid-slope region north of a plunging anticline. The section of slope containing diffuse, pockmarked gullies has a lower measure of stability than a separate section containing gullies that have sharper boundaries and somewhat steeper sides. Such an association suggests that our slope-stability analysis relates to the stability of the gully sides. The remainder of the study area shows few obvious indications of slope instability except for a feature that has become known as the 'Humboldt Slide,' but it is too deep-seated to be amenable to the slope-stability-prediction techniques presented herein. In general, few slope failures have been mapped in the Eel margin study area despite the high level of seismicity, the relatively high rates of sediment accumulation, and the extent of gas charging observed by others.

  7. Impact of vegetation on stability of slopes subjected to rainfall - numerical aspect

    Science.gov (United States)

    Switala, Barbara Maria; Tamagnini, Roberto; Sudan Acharya, Madhu; Wu, Wei

    2015-04-01

    Recent years brought a significant development of soil bioengineering methods, considered as an ecological and economically effective measure for slope stabilization. This work aims to show the advantages of the soil bioengineering solutions for a slope subjected to a heavy rainfall, with the help of a numerical model, which integrates most of the significant plant and slope features. There are basically two different ways in which vegetation can affect stability of a slope: root reinforcement (mechanical impact) and root water uptake (evapotranspiration). In the numerical model, the first factor is modelled using the Cam-Clay model extended for unsaturated conditions by Tamagnini (2004). The original formulation of a constitutive model is modified by introducing an additional constitutive parameter, which causes an expansion of the yield surface as a consequence of an increase in root mass in a representative soil element. The second factor is the root water uptake, which is defined as a volumetric sink term in the continuity equation of groundwater flow. Water removal from the soil mass causes an increase in suction in the vicinity of the root zone, which leads to an increase in the soil cohesion and provides additional strength to the soil-root composite. The developed numerical model takes into account the above mentioned effects of plants and thus considers the multi-phase nature of the soil-plant-water relationship. Using the developed method, stability of some vegetated and non-vegetated slopes subjected to rainfall are investigated. The performance of each slope is evaluated by the time at which slope failure occurs. Different slope geometries and soil mechanical and hydrological properties are considered. Comparison of the results obtained from the analyses of vegetated and non-vegetated slopes leads to the conclusion, that the use of soil bioengineering methods for slope stabilization can be effective and can significantly delay the occurrence of a rainfall induced landslide. On the contrary, vegetation removal can have serious consequences, especially on steep and forested slopes.

  8. Static Linear and Nonlinear Analysis of R.C Building on Sloping Ground with Varying Hill Slopes

    Directory of Open Access Journals (Sweden)

    K.S.L.Nikhila

    2014-11-01

    Full Text Available Earthquake field investigations repeatedly confirm that irregular structures suffer more damage than their regular counterparts. This is recognized in seismic design codes, and restrictions on abrupt changes in mass and stiffness are imposed. Irregularities in dimensions affect the distribution of stiffness, and in turn affect capacity, while mass irregularities tend to influence the imposed demand. Elevation irregularities have been observed to cause story failures due to non-uniform distribution of demand-to-supply ratios along the height. Plan irregularities, on the other hand, cause non-uniform demand-to-capacity ratios amongst the columns. In this paper the structure chosen for study is a 4, 5 storied commercial complex building. The building is located in seismic zone IV on a rock soil site. Three dimensional mathematical models for the same are generated in ETABS software. The structural elements, M40 grade of concrete, floor diaphragms are assumed to be rigid. Seismic loads were considered acting in the horizontal direction along either of the two principal directions and the ground slope choosen in between 0° and 25° and building that which produce less torsion effect for setback - stepback with irregular configuration in horizontal and vertical direction is modeled and analyzed.

  9. Experimental Observations On Turbidity Currents Flowing Over Low Bed Slopes

    Science.gov (United States)

    Stagnaro, M.; Bolla Pittaluga, M.

    2012-12-01

    Turbidity currents are gravity-driven, sediment-laden turbulent flows moving on a sloping bottom, which take place in oceans and lakes. Due to the difficulties to predict and observe this kind of phenomena in nature, in the recent past many experimental apparatus were set up to increase the comprehension of the currents. We developed an experimental apparatus able to reproduce such kind of currents in our Marchi Environmental Laboratory. The experiments were performed in an horizontal flume U shaped in plan, 30 m long, characterized by two straight tracks approximately 12 m in length, and a bend with a constant radius of curvature equal to 2.5 m. The flume, made in plexiglass, has a rectangular cross section 0.6 m wide and 0.5 m deep. The particular shape of the channel let us study the spatial development of turbidity (or saline) currents in the straight reach and the adjustment of the flow in the channel bend. We have created a concrete fixed bed with an uniform bottom slope of 0.005 developing both along the first straight and the constant curvature bend and continuing 3 meters after the bend exit. The first set of experimental observations were performed employing an 'hybrid' turbidity current, in that the density excess was created by adding both salt and fine sediments (d50=4 micron) to clear water. Each run, characterized by the same initial and boundary conditions (fractional density excess, discharge of the mixture, inlet and outlet conditions) and by the same geometry, was repeated many times in order to measure vertical velocity and density profiles in different cross sections along the straight and bend reaches. Both longitudinal and lateral velocity measurements were performed, as well as density profiles. The velocity profiles were acquired using an ultrasound Doppler velocimeter profiler. In this way we recorded the longitudinal velocity in the channel axis with a spatial resolution of 1 m along the flume and, coupling the data of two probes aligned in the cross section with different angles, we were able to obtain the vertical profiles of the secondary flow in the central region of the flume. The density profiles were obtained using two ranks of siphons that take samples of the current water at different heights from the bottom. The ongoing experimental observations will allow to provide detailed measurements on both flow velocity and suspended sediment concentration of subcritical turbidity currents flowing in constant curvature bend and shed some light on the ongoing debate concerning the orientation of secondary flow in submarine channels. At present we have completed the first set of runs, performed with a flow discharge Q=2 l/s and a density of the mixture ?_{mix}=1021 kg/m^3 that provides a relative excess density equal to 0,023. The current was subcritical both in the straight and curved reach and characterized by an average densimetric Froude number approximately equal to 0.70. Secondary flow in the curved bend was characterized by a river like orientation, i.e. inward oriented close to the bed and outward oriented above. In the next sets of experiments we plan to perform further runs by changing the density of the mixture and the flow discharge in order to observe their effect on the evolution of the turbidity current. These further results will be hopefully presented at the meeting.

  10. GPU Accelerated Numerical Simulation of Viscous Flow Down a Slope

    Science.gov (United States)

    Gygax, Remo; Räss, Ludovic; Omlin, Samuel; Podladchikov, Yuri; Jaboyedoff, Michel

    2014-05-01

    Numerical simulations are an effective tool in natural risk analysis. They are useful to determine the propagation and the runout distance of gravity driven movements such as debris flows or landslides. To evaluate these processes an approach on analogue laboratory experiments and a GPU accelerated numerical simulation of the flow of a viscous liquid down an inclined slope is considered. The physical processes underlying large gravity driven flows share certain aspects with the propagation of debris mass in a rockslide and the spreading of water waves. Several studies have shown that the numerical implementation of the physical processes of viscous flow produce a good fit with the observation of experiments in laboratory in both a quantitative and a qualitative way. When considering a process that is this far explored we can concentrate on its numerical transcription and the application of the code in a GPU accelerated environment to obtain a 3D simulation. The objective of providing a numerical solution in high resolution by NVIDIA-CUDA GPU parallel processing is to increase the speed of the simulation and the accuracy on the prediction. The main goal is to write an easily adaptable and as short as possible code on the widely used platform MATLAB, which will be translated to C-CUDA to achieve higher resolution and processing speed while running on a NVIDIA graphics card cluster. The numerical model, based on the finite difference scheme, is compared to analogue laboratory experiments. This way our numerical model parameters are adjusted to reproduce the effective movements observed by high-speed camera acquisitions during the laboratory experiments.

  11. Economics of Alaska North Slope gas utilization options

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, C.P.; Doughty, T.C.; Hackworth, J.H.; North, W.B.; Robertson, E.P.

    1996-08-01

    The recoverable natural gas available for sale in the developed and known undeveloped fields on the Alaskan North Slope (ANS) total about 26 trillion cubic feet (TCF), including 22 TCF in the Prudhoe Bay Unit (PBU) and 3 TCF in the undeveloped Point Thomson Unit (PTU). No significant commercial use has been made of this large natural gas resource because there are no facilities in place to transport this gas to current markets. To date the economics have not been favorable to support development of a gas transportation system. However, with the declining trend in ANS oil production, interest in development of this huge gas resource is rising, making it important for the U.S. Department of Energy, industry, and the State of Alaska to evaluate and assess the options for development of this vast gas resource. The purpose of this study was to assess whether gas-to-liquids (GTL) conversion technology would be an economic alternative for the development and sale of the large, remote, and currently unmarketable ANS natural gas resource, and to compare the long term economic impact of a GTL conversion option to that of the more frequently discussed natural gas pipeline/liquefied natural gas (LNG) option. The major components of the study are: an assessment of the ANS oil and gas resources; an analysis of conversion and transportation options; a review of natural gas, LNG, and selected oil product markets; and an economic analysis of the LNG and GTL gas sales options based on publicly available input needed for assumptions of the economic variables. Uncertainties in assumptions are evaluated by determining the sensitivity of project economics to changes in baseline economic variables.

  12. Nitrogen deposition along differently exposed slopes in the Bavarian Alps.

    Science.gov (United States)

    Kirchner, Manfred; Fegg, Wolfgang; Römmelt, Horst; Leuchner, Michael; Ries, Ludwig; Zimmermann, Ralf; Michalke, Bernd; Wallasch, Markus; Maguhn, Jürgen; Faus-Kessler, Theresa; Jakobi, Gert

    2014-02-01

    The Alps are affected by high nitrogen deposition, particularly in the fringe of the Northern and Southern Alps. In the framework of a two-year monitoring study performed in 2010 and 2011, we investigated the ammonia and nitrogen dioxide air concentration and ammonium and nitrate deposition at different altitudes between 700 and 1,600 ma.s.l. in the Garmisch-Partenkirchen district in the Upper Bavaria region (Germany). Four-weekly measurements of deposition collected with bulk open field samplers and under-crown were performed in a profile perpendicular to the axis of the Loisach valley; measurements were conducted at eight sites. Whereas open field deposition ranged from 5 to 11 kg ha(-1)a(-1), nitrogen throughfall has reached up to 21 kg ha(-1)a(-1). Data from the valley and the slopes were compared with measurements performed on the platform of the Environmental Research Station Schneefernerhaus (Zugspitze) at an altitude of 2,650 ma.s.l. For the rough estimation of the total yearly deposition rate of nitrogen, the canopy uptake model was applied. By regarding nitrogen uptake by the trees, total deposition can exceed the throughfall in all sites by up to 50%. Additionally, we estimated the total deposition from the sum of wet and dry deposition. On the one side, the wet deposition could be extrapolated from the open field deposition. On the other side, we used the inferential method to calculate the dry deposition on the basis of NH3 and NO2 air concentrations and their literature based deposition velocities. Since fixed deposition velocities are inappropriate particularly in complex orography, we tried to find correction factors based upon terrain characteristics and meteorological considerations. Temperature monitoring at the eight sites and wind measurements at two sites provided some evidence for the semi-empirical parameterization. Due to numerous imponderabilities, the results of the two methods were not consistent for all sites. PMID:24211349

  13. Large gravitational rock slope deformation in Romsdalen Valley (Western Norway

    Directory of Open Access Journals (Sweden)

    Aline Saintot

    2012-09-01

    Full Text Available Large gravitational rock slope deformation affects Precambrian gneisses at four localities of the Romsdalen valley of Western Norway. At each locality, detailed studies have allowed to determine the mechanism of deformation and to assess the degree of susceptibility for failure. 1 Svarttinden is a 4.3 Mm³ translational rockslide. Its single basal detachment developed along a foliation-parallel cataclastic fault. Although a rockslide occurred along the same detachment and the deposits reached the edge of the plateau, no displacement of the current instability is detected. 2 At Flatmark distinct 2-25 Mm³ blocks detached from the edge of the plateau by an opening along the steep foliation. The collapse of the blocks is explained by a complex mechanism of sliding and toppling. No displacement is actually detected on the instabilities. 3 At Børa blocks located at the edge of the plateau deformed by the same mechanism as at Flatmark. They have a maximum volume of 0.5 Mm3 and displacement rates of 0.2-2 cm/year. The deformation at Børa has affected a large part of the plateau and the entire deformed volume would be of 50-200 Mm³ but it is currently inactive. 4 A wedge failure at the edge of Mannen plateau is inferred to allow the 4-5 cm/year downward displacement of a 2-3.5 Mm³ instability. The high susceptibility of failure led to a permanent monitoring of the site since 2009.

  14. Exporting Alaskan North Slope crude oil: Benefits and costs

    International Nuclear Information System (INIS)

    The Department of Energy study examines the effects of lifting the current prohibitions against the export of Alaskan North Slope (ANS) crude. The study concludes that permitting exports would benefit the US economy. First, lifting the ban would expand the markets in which ANS oil can be sold, thereby increasing its value. ANS oil producers, the States of California and Alaska, and some of their local governments all would benefit from increased revenues. Permitting exports also would generate new economic activity and employment in California and Alaska. The study concludes that these economic benefits would be achieved without increasing gasoline prices (either in California or in the nation as a whole). Lifting the export ban could have important implications for US maritime interests. The Merchant Marine Act of 1970 (known as the Jones Act) requires all inter-coastal shipments to be carried on vessels that are US-owned, US-crewed, and US-built. By limiting the shipment of ANS crude to US ports only, the export ban creates jobs for the seafarers and the builders of Jones Act vessels. Because the Jones Act does not apply to exports, however, lifting the ban without also changing US maritime law would jeopardize the jobs associated with the current fleet of Jones Act tankers. Therefore the report analyzes selected economic impacts of several maritime policy alternatives, including: Maintaining current law, which allows foreign tankers to carry oil where export is allowed; requiring exports of ANS crude to be carried on Jones Act vessels; and requiring exports of ANS crude to be carried on vessels that are US-owned and US-crewed, but not necessarily US-built. Under each of these options, lifting the export ban would generate economic benefits

  15. Economics of Alaska North Slope gas utilization options

    International Nuclear Information System (INIS)

    The recoverable natural gas available for sale in the developed and known undeveloped fields on the Alaskan North Slope (ANS) total about 26 trillion cubic feet (TCF), including 22 TCF in the Prudhoe Bay Unit (PBU) and 3 TCF in the undeveloped Point Thomson Unit (PTU). No significant commercial use has been made of this large natural gas resource because there are no facilities in place to transport this gas to current markets. To date the economics have not been favorable to support development of a gas transportation system. However, with the declining trend in ANS oil production, interest in development of this huge gas resource is rising, making it important for the U.S. Department of Energy, industry, and the State of Alaska to evaluate and assess the options for development of this vast gas resource. The purpose of this study was to assess whether gas-to-liquids (GTL) conversion technology would be an economic alternative for the development and sale of the large, remote, and currently unmarketable ANS natural gas resource, and to compare the long term economic impact of a GTL conversion option to that of the more frequently discussed natural gas pipeline/liquefied natural gas (LNG) option. The major components of the study are: an assessment of the ANS oil and gas resources; an analysis of conversion and transportation options; a review of natural gas, LNG, and selected oil product markets; and an economic analysis of the LNG and GTL gas sales options based on publicly available input needed for assumptions of the economic variables. Uncertainties in assumptions are evaluated by determining the sensitivity of project economics to changes in baseline economic variables

  16. Exporting Alaskan North Slope crude oil: Benefits and costs

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    The Department of Energy study examines the effects of lifting the current prohibitions against the export of Alaskan North Slope (ANS) crude. The study concludes that permitting exports would benefit the US economy. First, lifting the ban would expand the markets in which ANS oil can be sold, thereby increasing its value. ANS oil producers, the States of California and Alaska, and some of their local governments all would benefit from increased revenues. Permitting exports also would generate new economic activity and employment in California and Alaska. The study concludes that these economic benefits would be achieved without increasing gasoline prices (either in California or in the nation as a whole). Lifting the export ban could have important implications for US maritime interests. The Merchant Marine Act of 1970 (known as the Jones Act) requires all inter-coastal shipments to be carried on vessels that are US-owned, US-crewed, and US-built. By limiting the shipment of ANS crude to US ports only, the export ban creates jobs for the seafarers and the builders of Jones Act vessels. Because the Jones Act does not apply to exports, however, lifting the ban without also changing US maritime law would jeopardize the jobs associated with the current fleet of Jones Act tankers. Therefore the report analyzes selected economic impacts of several maritime policy alternatives, including: Maintaining current law, which allows foreign tankers to carry oil where export is allowed; requiring exports of ANS crude to be carried on Jones Act vessels; and requiring exports of ANS crude to be carried on vessels that are US-owned and US-crewed, but not necessarily US-built. Under each of these options, lifting the export ban would generate economic benefits.

  17. Systematic of the slope-mass-correlations in diffractive dissociation reactions

    International Nuclear Information System (INIS)

    A set of several results of the Three Components Deck Model for Diffractive Dissociation Reactions is presented. News and recently published results are summarized to obtain a general overview of the model, its predictions and comparison with experimental results. Two kinds of correlations and amplitudes are given: The slope-mass cos theta sup(GJ) correlation and slope-mass partial wave. (Author)

  18. Laboratory Experiments on Steady State Seepage-Induced Landslides Using Slope Models and Sensors

    Directory of Open Access Journals (Sweden)

    Sandra G. Catane

    2011-06-01

    Full Text Available A thorough understanding of the failure initiation process is crucial in the development of physicallybased early warning system for landslides and slope failures. Laboratory-scale slope models were constructed and subjected to instability through simulated groundwater infiltration. This is done by progressively increasing the water level in the upslope tank and allowing water to infiltrate laterally towards the toe of the slope. Physical changes in the slope models were recorded by tilt sensors and video cameras. When the model slope was destabilized, the chronology of events occurred in the following sequence: (1 bulging at the toe, (2 seepage at the toe, (3 initial failure of soil mass, (4 piping, (5 retrogressive failure, (6 formation of tension cracks and (7 major failure of soil mass. Tension cracks, piping and eventual failure are manifestations of differential settlements due to variations in void ratio. Finite element analysis indicates that instability and subsequent failures in the model slope were induced primarily by high hydraulic gradients in the toe area. Seepage, initial deformation and subsequent failures were manifested in the toe area prior to failure, providing a maximum of 36 min lead time. Similar lead times are expected in slopes of the same material as shown in many case studies of dam failure. The potential of having a longer lead time is high for natural slopes made of materials with higher shear strength thus evacuation is possible. The tilt sensors were able to detect the initial changes before visual changes manifested, indicating the importance of instrumental monitoring.

  19. Index of streamflow and water quality records to September 30, 1978, Arctic Slope, Alaska

    Science.gov (United States)

    Still, Patsy J.

    1980-01-01

    This report, which is one of a series of reports for Alaska, lists stations in Arctic Slope, Alaska, at which streamflow and water quality data have been collected by the U.S. Geological Survey. Included are a hydrologic subregion map of Arctic Slope, Alaska, and a table listing the types of data collected and periods of record. (USGS)

  20. Constructing Graphical Representations: Middle Schoolers' Intuitions and Developing Knowledge about Slope and Y-Intercept

    Science.gov (United States)

    Hattikudur, Shanta; Prather, Richard W.; Asquith, Pamela; Alibali, Martha W.; Knuth, Eric J.; Nathan, Mitchell

    2012-01-01

    Middle-school students are expected to understand key components of graphs, such as slope and y-intercept. However, constructing graphs is a skill that has received relatively little research attention. This study examined students' construction of graphs of linear functions, focusing specifically on the relative difficulties of graphing slope and…