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1

Adolescent fracture of the talus associated with talus partitus.  

UK PubMed Central (United Kingdom)

A case report of an adolescent with a fracture of the talus with an associated talus partitus is presented. Unlike the more common os trigonum, which arises from a secondary ossification center, the talus partitus is substantially larger and may include articulation with the ankle and subtalar joint, making its preservation via osteosynthesis with the talus desirable.

Serrato J; Bennett JT

2013-01-01

2

La vegetación saxícola y de taludes del flanco oriental del Cordón del Plata (Luján de Cuyo, Mendoza, Argentina) Saxicolous and talus vegetation on the eastern slope of Cordón del Plata (Luján de Cuyo, Mendoza, Argentina)  

Directory of Open Access Journals (Sweden)

Full Text Available A fin de complementar estudios de vegetación de la vertiente oriental del Cordón del Plata de los altos Andes Centrales de Luján de Cuyo, Mendoza, Argentina, se determina y analiza, las comunidades saxícolas y de taludes a lo largo de un gradiente altitudinal de 1200 a 3200 m s.n.m. El estudio fitosociológico revela la existencia de 17 comunidades vegetales: 7 saxícolas y 12 de taludes, caracterizadas por especies diagnósticas exclusivas, diferenciales y acompañantes. Análisis de dispersión y de conglomerados permiten, utilizando las altitudes y temperaturas, diferenciar a 3 grupos de comunidades las que se corresponden, y confirman el análisis fitosociológico, a los ambientes fitogeográficos del Monte, Andino y Andino Superior. Existe una fuerte relación florística-ecológica de estas comunidades saxícolas y de taludes con los espectros de los ambientes fitogeográficos, las formas de vida y los orígenes de las especies desarrolladas en el gradiente altitudinal del área analizada. Se registraron 63 especies endémicas: 7 endemismos locales, 28 regionales y 26 nacionales. Las comunidades vegetales obtenidas se comparan con la de otras áreas de Argentina.In order to supplement studies of the vegetation on the eastern slope of Cordón del Plata in the high Central Andes of Luján de Cuyo, Mendoza, Argentina, saxicolous and talus plant communities are determined and analyzed along the altitudinal gradient from 1200 to 3200 m a. s. l. Phytosociological study reveals occurrence of 17 plant communities: 7 saxicolous and 12 talus communities, characterized by exclusive, differential and accompanying diagnostic species. Conglomerate and dispersal analyses, using altitude and temperature, allow differentiation of three groups of communities which correspond, corroborating the phytosociological analysis, to the Monte, Andean and High Andean phytogeographic environments. There is a strong floristic-ecological relationship of these saxicolous and talus plant communities with spectra of phytogeographic environments, life forms and origins of species developed along the altitudinal gradient of the study area. A total of 63 endemic species were recorded: 7 local, 28 regional and 26 national endemisms. The plant communities obtained are compared with those of other areas of Argentina.

Eduardo Méndez

2010-01-01

3

Chondroblastoma of the talus.  

UK PubMed Central (United Kingdom)

We report the case of a 13-year-old male child who presented with a painful left ankle. On imaging (radiography and computed tomography scan with 3-dimensional reconstruction views), an osteolytic lesion in the body of the talus was revealed. Open biopsy, curettage, and fibular bone grafting were done, and the specimen was sent for histopathologic examination. The histopathologic report confirmed the specimen to be chondroblastoma of the talus bone. Chondroblastoma is a rare benign cartilaginous neoplasm that accounts for approximately 1% of all bone tumors and characteristically arises in the epiphysis of a long bone, particularly the humerus, tibia, and femur. Chondroblastoma can affect people of all ages. It is, however, most common in children and young adults aged 10 to 20 years. Chondroblastoma in a tarsal bone is a rare entity. Managing chondroblastoma of the talus with curettage and bone grafting has shown good outcomes.

Ningegowda RV; Subramanian K; Suresh I

2013-09-01

4

Chondroblastoma of the talus.  

Science.gov (United States)

We report the case of a 13-year-old male child who presented with a painful left ankle. On imaging (radiography and computed tomography scan with 3-dimensional reconstruction views), an osteolytic lesion in the body of the talus was revealed. Open biopsy, curettage, and fibular bone grafting were done, and the specimen was sent for histopathologic examination. The histopathologic report confirmed the specimen to be chondroblastoma of the talus bone. Chondroblastoma is a rare benign cartilaginous neoplasm that accounts for approximately 1% of all bone tumors and characteristically arises in the epiphysis of a long bone, particularly the humerus, tibia, and femur. Chondroblastoma can affect people of all ages. It is, however, most common in children and young adults aged 10 to 20 years. Chondroblastoma in a tarsal bone is a rare entity. Managing chondroblastoma of the talus with curettage and bone grafting has shown good outcomes. PMID:23540757

Ningegowda, Ravish V; Subramanian, Karthik; Suresh, I

2013-03-26

5

Traumatic extrusion of the talus (missing talus).  

UK PubMed Central (United Kingdom)

Complete dislocation of the talus is an extremely rare injury. We report on a case that was treated according to a surgical technique described by Günal et al. According to this technique, a pseudarthrosis is created between the tibia and the calcaneus by transposing and fixing the medial malleolus laterally and displacing the entire foot anteriorly. The result was considered to be initially unsatisfactory. At the 2-year follow-up examination, the outcome was considered to be satisfactory. This was attributed to preservation of motion and stability in the new mortise.

Papaioannou NA; Kokoroghiannis CG; Karachalios GG

1998-09-01

6

Surgical treatment of talus fractures.  

Science.gov (United States)

Talus fractures result from high-energy mechanisms and usually occur at the neck. Functional outcome after talar neck fracture worsens with increasing Hawkins grade. The mainstay of treatment for talar neck fractures is anatomic reduction and internal fixation. Prompt reduction of dislocations should be performed. Patients should be taken to the operating room as soon as stabilized. Dual incisions and a combination of minifragment plates and screws should be used. Talar body fractures have a high rate of ankle and subtalar arthritis. Lateral process fractures are frequently missed on radiographs. Complications after talus fractures include osteonecrosis, malunion, post-traumatic arthritis, and infection. PMID:24095068

Shakked, Rachel J; Tejwani, Nirmal C

2013-08-12

7

[Talus necrosis and its treatment  

UK PubMed Central (United Kingdom)

Aetiopathogenesis of the necrosis of the talus has not yet been definitely clarified, and neither has that of the other aseptic necroses. We were able to study the aetiopathogenesis, course of the disease and therapy in 20 of our own patients by follow-up; two of these developed necrosis of the talus in both feet. We definitely excluded patients suffering from osteochondrosis dissecans. Even though fracture of the talus is on the whole relatively rare, it remains the most frequent cause of necrosis of the talus. We also found talonecrosis after surgical correction of clubfoot, after Sudeck's disease (Sudeck-Leriche syndrome, Sudeck's atrophy or dystrophy), suppurative arthritis of the ankle joint, subtalar luxation and haematogenic osteomyelitis. Only few patients required surgery. In most cases a special boot constructed for arthrodesis patients proved sufficient. Each patient developed arthrodesis to a different degree. Depending upon the complaints and stiffening of the ankle joint or of the talo-calcanonavicular joint, the capacity of the patients to be gainfully employed was reduced by an amount between 20 and 30 per cent.

Trauth J; Bläsius K

1988-08-01

8

Impact of erosion in the taluses of subtropical orchard terraces.  

UK PubMed Central (United Kingdom)

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 is terracing. We hypothesise that despite these soil-conservation measures erosion remains a major problem in these steep uplands. Soil loss and runoff were evaluated over a 2-year period (2001-2002) on the taluses of terraces, in this zone of intense subtropical orchard cultivation. The experimental erosion plots (4 m x 4 m in area) were located on a terrace of 214% (65 degrees) slope at 180 m in altitude. The results indicated that soil loss occurs from rainfall runoff depositing topsoil at the foot of the terrace. The average annual soil loss by erosion from the taluses of the orchard terraces was 9.1 Mg ha(-1) year(-1), with a runoff of 100 mm year(-1) and a rain erosivity index (EI30) of 219.7 MJ mm ha(-1) h(-1). Therefore, under these conditions the terraces had a high risk of rockslide and slump, causing environmental and agricultural damages. The runoff coefficients ranged from 6 to 31%, depending on the intensity and energy of the rainfall events. The present study highlights the severity of erosion in taluses of orchard terraces of southeast Spain and reflects the urgency of planning strategies to protect these structures against chronic destruction.

Zuazo VHD; Ruiz JA; Raya AM; Tarifa DF

2005-05-01

9

Chance fracture of the talus and calcaneum.  

Science.gov (United States)

Combined talus and calcaneum fractures are rare in themselves. We report the case of an unusual fracture pattern of the talus and calcaneum in an otherwise, healthy 17-year-old male. Plain radiographic images of the foot revealed a fracture through the neck of the talus. Additional computed tomography imaging showed the fracture line extending through the talus and entire calcaneum. The fracture was open and associated with rupture of the tibialis anterior and extensor hallucis longus tendons. The patient underwent debridement with open reduction and internal fixation of the talar component of the fracture using 2 screws. The calcaneal component was treated conservatively. The soft tissue injuries to the 2 tendons were also repaired. The patient made good progress with this management. PMID:23621978

Lancaster, Sarah; Harries, William

10

Chance fracture of the talus and calcaneum.  

UK PubMed Central (United Kingdom)

Combined talus and calcaneum fractures are rare in themselves. We report the case of an unusual fracture pattern of the talus and calcaneum in an otherwise, healthy 17-year-old male. Plain radiographic images of the foot revealed a fracture through the neck of the talus. Additional computed tomography imaging showed the fracture line extending through the talus and entire calcaneum. The fracture was open and associated with rupture of the tibialis anterior and extensor hallucis longus tendons. The patient underwent debridement with open reduction and internal fixation of the talar component of the fracture using 2 screws. The calcaneal component was treated conservatively. The soft tissue injuries to the 2 tendons were also repaired. The patient made good progress with this management.

Lancaster S; Harries W

2013-05-01

11

[Minimally invasive osteosynthesis. : even in talus fractures?].  

UK PubMed Central (United Kingdom)

OBJECTIVE: Minimally invasive osteosynthesis of talar fractures. INDICATIONS: Minimally displaced fractures of the lateral process of the talus and talar neck fractures type 1 according to Hawkins classification. CONTRAINDICATIONS: Dislocated peripheral fractures. Displaced fractures of the talar neck or body. SURGICAL TECHNIQUE: For factures of the lateral process of the talus: short incision of skin over the lateral process of the talus. Gentle preparation and contact with the bone with scissors. Fragment reposition using a dentist's hook and Kirschner wire in a joy-stick technique under C-arm imaging. Stabilization with a miniscrew. For talar neck fracture Hawkins type 1: short incision of skin ventromedially and ventrolaterally. Blunt preparation of soft tissue and safe bone contact. Introduction of one small-fragment corticalis screw both medially and laterally under C-arm imaging. As an alternative, cannulated screws can also be used. POSTOPERATIVE MANAGEMENT: For fractures of the lateral process of the talus: postoperative protection in an ankle splint (air cast, gel cast) for 4 weeks. During this time moderate weight bearing is possible. For talar neck fractures Hawkins type 1: physiotherapy and only floor contact for 6 weeks. RESULTS: From January 1996 to December 2002, 44 talar fractures were operatively treated in our department. Six patients had talar neck fractures type 1 according the Hawkins classification and 3 patients showed fractures of the lateral process of the talus. From those injuries, 3 Hawkins type 1 fractures and 2 fractures of the lateral process were stabilized using minimally invasive osteosynthesis. The clinical outcomes were assessed using the Ankle Hindfoot Scale of the American Orthopedic Foot and Ankle Society. Both groups reached good cosmetic and functional results. We did not observe any avascular talar necrosis or nonunions in the two groups.

Tezval M; Schmoz S; Dumont C

2012-09-01

12

14C age of the talus deposits distributed in the middle course of the river Obirashibe, northern Hokkaido, Japan  

International Nuclear Information System (INIS)

The samples for the determination of the 14C age of the talus deposit were collected from Takinoshita, Obira town, Rumoe district, Hokkaido. The stratigraphy and the sequence of deposits were as follows: 1) T1 terrace deposit, 2) mud flow deposit, 3) T2 terrace deposit (lake deposit), 4) talus deposit, 5) large rock slide. The obtained 14C age of 23750+-620 Y.B.P. showed the lower limit of talus deposit and the upper limit of lake deposit. The 14C age 29060+-2180 Y.B.P. of the mud flow deposit was regarded as the lower limit of the lake deposit. The formation of lake deposit was estimated to be in the period of 29000-24000 years ago. The obtained age showed good correspondence with the results of pollen analysis which indicated the climate-mitigating period in last glacial epoch. Consequently, the lake deposit of this area was regarded as to be formed in the similar weather condition mentioned above. Talus deposit contained wood pieces in its basement, but fossil pollens and the relics of lage plants were not found. This means that the talus deposit was formed continuously without vegetation. The weather condition in which the deposits were formed are as follows. 1) Mud flow deposit was formed by the large collapse of mountain side slope in the last stage of [Biraotori moor period]. 2) Lake deposit was formed in the period of weather mitigation of 29000-26000 years ago. 3) Talus deposit was formed under the cold and dry periglacial condition 24000 years ago and on. (Ishimitsu, A.)

1983-01-01

13

Palaeoclimatic considerations of talus flatirons and aeolian deposits in Northern Fuerteventura volcanic island (Canary Islands, Spain)  

Science.gov (United States)

Fuerteventura volcanic island has been subject to considerable aeolian activity since the Late Pleistocene. The aeolian record includes inactive aeolian deposits with interbedded entisols, whose age by OSL dating ranges between 46 and 26 ky BP. The Corralejo active dune field, where sand sheets, nebkhas, coppice dunes, blowouts, barchans and transverse dunes have been described, constitutes a more recent Aeolian deposit. Here the age is about 14 ky BP. On Fuerteventura Island aeolian dust has been deposited on valleys and slopes. This last type of accumulation has been affected by gully incision, producing talus flatirons. Samples taken on the apex of these palaeo-slopes indicate an OSL age of 30 and 50 ky BP. A palaeoclimatic succession has been interpreted during which a prevailing arid period took place in OIS 4, with the accumulation of aeolian dust. A humid period occurred in OIS 2, during which slopes were dissected and formed talus flatirons. An arid period about 14 ky BP gave rise to the Corralejo dune field, which has continued until present with slight climatic oscillations.

Gutiérrez-Elorza, Mateo; Lucha, Pedro; Gracia, F.-Javier; Desir, Gloria; Marín, Cinta; Petit-Maire, Nicole

2013-09-01

14

An unusual fracture of the talus in a snowboarder.  

Science.gov (United States)

Fractures of the talus are uncommon. However, snow- boarding and skateboarding are 2 activities that are specifically associated with talus fractures. These patients sustain occult lateral talus process fractures that present as a severe ankle injury. The diagnosis is difficult because of subtle clinical and plain radiographic findings. Computed tomography is a very useful tool for the assessment of these injuries. Although the majority of these athletes have lateral sided talus fractures, there are variants. We present an unusual case of a displaced intra-articular fracture of the subtalar joint involving the middle articular facet of the talus with extension of the fracture into the talar head. This highlights the importance of carefully assessing snowboarders' "ankle injuries." PMID:16056086

Vlahovich, A Tanja; Mehin, Ramin; O'Brien, Peter J

2005-08-01

15

An unusual fracture of the talus in a snowboarder.  

UK PubMed Central (United Kingdom)

Fractures of the talus are uncommon. However, snow- boarding and skateboarding are 2 activities that are specifically associated with talus fractures. These patients sustain occult lateral talus process fractures that present as a severe ankle injury. The diagnosis is difficult because of subtle clinical and plain radiographic findings. Computed tomography is a very useful tool for the assessment of these injuries. Although the majority of these athletes have lateral sided talus fractures, there are variants. We present an unusual case of a displaced intra-articular fracture of the subtalar joint involving the middle articular facet of the talus with extension of the fracture into the talar head. This highlights the importance of carefully assessing snowboarders' "ankle injuries."

Vlahovich AT; Mehin R; O'Brien PJ

2005-08-01

16

Entire posterior process talus fracture: a report of two cases.  

UK PubMed Central (United Kingdom)

The complex anatomy of the posterior process of the talus includes the medial and lateral tubercles extending from the talar body. Review of the current literature indicates that fracture of the entire posterior process of the talus is a rare injury. Two patients presented to our emergency department after motor vehicle accidents, and both were diagnosed with entire posterior process talus fractures. After evaluation of each patient, treatment of each was undertaken by means of open reduction and internal fixation via the posteromedial approach to fracture. Headless screws were used to fixate the reduced posterior tubercle in each case. Based on our experience with the patients described in this report, open reduction and internal fixation appear to be suitable methods of treatment for complete posterior process fractures of the talus.

Mehrpour SR; Aghamirsalim MR; Sheshvan MK; Sorbi R

2012-05-01

17

Congenital vertical talus in multiple pterygium syndrome.  

UK PubMed Central (United Kingdom)

BACKGROUND: Congenital vertical talus (CVT) is a rare foot deformity, but it is a commonly associated anomaly in patients with multiple pterygium syndrome (MPS). If left untreated, it can cause pain and morbidity, which will affect the patient's ambulation and quality of life. The aim of this study was to assess the prevalence of CVT among patients with MPS, to characterize the clinical and radiological features and examine the outcome of treatment. METHODS: We reviewed the medical records from 1969 to 2009, and detected 14 patients with a diagnosis of MPS. Data regarding clinical findings, radiographs, associated anomalies, and treatment were collected and analyzed. RESULTS: CVT was seen in 10 of 14 patients (71%). All of them had bilateral involvement. Eight of the 10 (80%) were girls, and 3 of these 10 (30%) were nonambulatory patients. All 7 ambulatory patients had manipulation and casting, followed by a single-stage surgical release. The mean age at surgery was 3.0 ± 3.7 years (range, 3 mo-9 y 2 mo). At the last follow-up, all of the 7 patients (100%) had painless plantigrade feet and a reduced talonavicular joint, and none had recurrence of the deformity. The overall mean follow-up was 6 years (range, 2-19 y) and the mean age at the last follow-up was 9 years (range, 2-23 y). The commonly associated anomalies were scoliosis (93%), tethered cord (14%), hip dislocation (43%), cardiac (29%), respiratory (43%), and gastrointestinal anomalies (29%). CONCLUSIONS: CVT is common in MPS. The other common anomalies included scoliosis, hip dislocation, and respiratory problems. Treatment with manipulation and casting followed by, a single-stage surgical release resulted in a good outcome.

Angsanuntsukh C; Oto M; Holmes L; Rogers KJ; King MM; Donohoe M; Kumar SJ

2011-07-01

18

[Osteochondritis dissecans of the talus. Diagnosis and treatment].  

UK PubMed Central (United Kingdom)

Osteochondritis dissecans of the talus (ODT) describes a special entity of osteochondral lesions of the talus (OLT) which has to be distinguished from acute traumatic lesions. Its exact etiology still remains uncertain with multiple predispositioning factors being discussed. Following the knee and elbow, the ankle joint with 4% is the third most affected joint. Early stages can often be treated conservatively. In case of an advanced stage or failure of conservative treatment, a variety of operative techniques are available, which can be used based on the patient and the stage.

Preiss A; Heitmann M; Frosch KH

2012-12-01

19

Congenital vertical talus: Treatment by reverse ponseti technique  

Directory of Open Access Journals (Sweden)

Full Text Available Background: The surgery for idiopathic congenital vertical talus (CVT) can lead to stiffness, wound complications and under or over correction. There are sporadic literature on costing with mixed results. We describe our early experience of reverse ponseti technique. Materials and methods: Four cases (four feet) of idiopathic congenital vertical talus (CVT) which presented one month after birth were treated by serial manipulation and casting, tendoachilles tenotomy and percutaneous pinning of talonavicular joint. An average of 5.2 (range - four to six) plaster cast applications were required to correct the forefoot deformity. Once the talus and navicular were aligned based on the radiographic talus-first metatarsal axis, percutaneous fixation of the talo-navicular joint with a Kirschner wire, and percutaneous tendoachilles tenotomy under anesthesia was performed following which a cast was applied with the foot in slight dorsiflexion. Results: The mean follow-up period for the four cases was 8.5 months (6-12 months). At the end of the treatment all feet were supple and plantigrade but still using ankle foot orthosis (AFO). The mean talocalcaneal angle was 70 degrees before treatment and this reduced to 31 degrees after casting. The mean talar axis first metatasal base angle (TAMBA) angle was 60° before casting and this improved to 10.5°. Conclusion: Although our follow-up period is small, we would recommend early casting for idiopathic CVT along the same lines as the Ponseti technique for clubfoot except that the forces applied are in reverse direction. This early casting method can prevent extensive surgery in the future, however, a close vigil is required to detect any early relapse.

Bhaskar Atul

2008-01-01

20

Bone Microarchitecture of the Talus Changes With Aging.  

UK PubMed Central (United Kingdom)

BACKGROUND: Fractures of the talus in the elderly are rare and usually result from high-impact injuries, suggesting only minor age-related bone structure changes. However, total ankle replacement failures with age often result from talar subsidence, suggesting age-related bone loss in the talus. Despite a number of histological analyses of talar microarchitecture, the effects of age and sex on talar microarchitecture changes remain poorly defined. QUESTIONS/PURPOSES: The aim of this study was to analyze changes or differences in the trabecular microarchitecture of the talus with regard to (1) age and (2) sex. METHODS: Sixty human tali were harvested from 30 patients at autopsy of three different age groups (20-40, 41-60, 61-80 years). The specimens were analyzed by radiography, micro-CT, and histological analysis. Given that there was no difference between the left and right talus, static histomorphometric parameters were assessed in three regions of interest of the right talus only (body, neck, head; n = 30). RESULTS: The talar body, neck, and head were affected differently by age-related changes. The greatest loss of bone volume with age was seen in the talar body (estimate: -0.239; 95% confidence interval [CI], -0.365 to -0.114; p < 0.001). In the talar neck (estimate: -0.165; 95% CI, -0.307 to -0.023; p = 0.025), bone loss was only moderate and primarily was the result of reduction in trabecular thickness (estimate: -1.288; 95% CI, -2.449 to -0.127; p = 0.031) instead of number (estimate: -0.001; 95% CI, -0.005 to -0.003; p = 0.593). Bone structure changes were independent of sex. CONCLUSIONS: Age-related bone structure changes predominantly occur in the talar body, which poses a potential risk factor for total ankle replacement loosening. The moderate changes in the talar neck might explain the persistent low incidence of talar neck fractures with age. CLINICAL RELEVANCE: Our findings suggest that before total ankle replacement implantation, careful patient selection with dual-energy xray absorptiometry evaluation may be necessary to reduce the risk of talar implant subsidence.

Krause M; Rupprecht M; Mumme M; Püschel K; Amling M; Barvencik F

2013-07-01

 
 
 
 
21

/sup 14/C age of the talus deposits distributed in the middle course of the river Obirashibe, northern Hokkaido, Japan. /sup 14/C age of the Quaternary deposits in Japan (146)  

Energy Technology Data Exchange (ETDEWEB)

The samples for the determination of the /sup 14/C age of the talus deposit were collected from Takinoshita, Obira town, Rumoe district, Hokkaido. The stratigraphy and the sequence of deposits were as follows: 1) T/sub 1/ terrace deposit, 2) mud flow deposit, 3) T/sub 2/ terrace deposit (lake deposit), 4) talus deposit, 5) large rock slide. The obtained /sup 14/C age of 23750+-620 Y.B.P. showed the lower limit of talus deposit and the upper limit of lake deposit. The /sup 14/C age 29060+-2180 Y.B.P. of the mud flow deposit was regarded as the lower limit of the lake deposit. The formation of lake deposit was estimated to be in the period of 29000-24000 years ago. The obtained age showed good correspondence with the results of pollen analysis which indicated the climate-mitigating period in last glacial epoch. Consequently, the lake deposit of this area was regarded as to be formed in the similar weather condition mentioned above. Talus deposit contained wood pieces in its basement, but fossil pollens and the relics of lage plants were not found. This means that the talus deposit was formed continuously without vegetation. The weather condition in which the deposits were formed are as follows. 1) Mud flow deposit was formed by the large collapse of mountain side slope in the last stage of (Biraotori moor period). 2) Lake deposit was formed in the period of weather mitigation of 29000-26000 years ago. 3) Talus deposit was formed under the cold and dry periglacial condition 24000 years ago and on.

Miyasaka, Seigo; Taira, Nobuyuki (Meiji Consultant Co. Ltd., Sapporo (Japan)); Igarashi, Yaeko

1983-05-01

22

Slope filtrations  

CERN Multimedia

Many slope filtrations occur in algebraic geometry, asymptotic analysis, ramification theory, p-adic theories, geometry of numbers... These functorial filtrations, which are indexed by rational (or sometimes real) numbers, have a lot of common properties. We propose a unified abstract treatment of slope filtrations, and survey how new ties between different domains have been woven by dint of deep correspondences between different concrete slope filtrations.

André, Yves

2008-01-01

23

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)

Full Text Available Abstract in spanish 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 (more) 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 (more) 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.

Fazal-ur-Rehman; Faruqi, Nafis A

2012-03-01

24

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)

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.

Fazal-ur-Rehman; Nafis A Faruqi

2012-01-01

25

Sports activity after osteochondral transplantation of the talus.  

UK PubMed Central (United Kingdom)

BACKGROUND: There are limited data regarding activity after osteochondral transplantation of the talus in orthopaedic publications. HYPOTHESIS: Osteochondral transplantation of the talus is a clinically successful treatment and enables patients to pursue regular and ongoing recreational sporting activities. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: One hundred thirty-one patients were retrospectively analyzed to determine their sporting and recreational activities at an average of 60 ± 28.4 months postoperatively (range, 24-141 months). The clinical evaluation included the Tegner activity scale, the Activity Rating Scale (ARS), and a visual analog scale (VAS) for pain. RESULTS: The VAS illustrated significant preoperative to postoperative improvements (6.3 to 2.7; P < .001). Regarding sporting activity, 96.9% of the patients were engaged in sports during their lifetimes compared with 83.8% the year before surgery and 89.3% at the time of survey. The Tegner score dropped from 5.9 preoperatively to 5.0 after surgery (P = .001), and the ARS decreased from 8.9 preoperatively to 6.8 postoperatively (P = .003). The sports frequency and the duration of activities did not significantly change after surgery: 1.7 ± 2.0 (range, 0-8; P = .053) and 4.2 ± 3.8 hours (range, 0-30 hours; P = .052), respectively. The number of actual reported different sports disciplines was unchanged in comparison to the year before surgery (3.7 ± 2.9; range, 0-12). The top 10 cited sports activities did not change for the lifetime, preoperative, and postoperative periods but illustrated an altered order. Although the overall satisfaction with the surgery was good, 15% of our patients were only partially satisfied, and 14% were not satisfied with the procedure. CONCLUSION: Patients engage in fewer, less frequent sporting activities when a symptomatic osteochondral lesion (OCL) at the talus is present. Talar osteochondral transplantation shows good clinical midterm results and allows patients to return to sporting activity. However, we found patients modify their postoperative sporting activities, and we noted a reduction of participation in high-impact and contact sports.

Paul J; Sagstetter M; Lämmle L; Spang J; El-Azab H; Imhoff AB; Hinterwimmer S

2012-04-01

26

FACETS FOR TALUS ON DORSAL SURFACE OF HUMAN CALCANEI  

Directory of Open Access Journals (Sweden)

Full Text Available OBJECTIVES: To find out the racial and regional diffences of articular facets on the dorsal surface of OSCalcisof Pakistani's of Punjab. MATERIAL AND METHODS: All the OS calcis (93) present in the bonebank of department of Anatomy Punjab Medical College Faisalabad were studied macroscopically with thehand lens. RESULTS: Type A = Calcanei with two anterior articular facets; Type B=Calcanei with singleanterior articular facets; Type C=Anterior and posterior articular facets confluent. We found 27.95% (26cases) type A calcanei and 72.04% (67 cases) type B calcanei. No calcanei of type C were seen.CONCLUSION: Variations of facets for talus on dorsal surface of calcanei are due to racial and regionaldifferences.

Imtiaz Ahmad

1997-01-01

27

Operative treatment of osteochondral lesions of the talus.  

UK PubMed Central (United Kingdom)

? Osteochondral lesions of the talus are common injuries in recreational and professional athletes, with up to 50% of acute ankle sprains and fractures developing some form of chondral injury. Surgical treatment paradigms aim to restore the articular surface with a repair tissue similar to native cartilage and to provide long-term symptomatic relief.? Arthroscopic bone-marrow stimulation techniques, such as microfracture and drilling, perforate the subchondral plate with multiple openings to recruit mesenchymal stem cells from the underlying bone marrow to stimulate the differentiation of fibrocartilaginous repair tissue in the defect site. The ability of fibrocartilage to withstand mechanical loading and protect the subchondral bone over time is a concern.? Autologous osteochondral transplantation techniques replace the defect with a tubular unit of viable hyaline cartilage and bone from a donor site in the ipsilateral knee. In rare cases, a graft can also be harvested from the ipsilateral talus or contralateral knee. The limitations of donor site morbidity and the potential need for an osteotomy about the ankle should be considered. Some anterior or far posterior talar lesions can be accessed without arthrotomy or with a plafondplasty.? Osteochondral allograft transplantation allows an osteochondral lesion with a large surface area to be replaced with a single unit of viable articular cartilage and subchondral bone from a donor that is matched to size, shape, and surface curvature. The best available evidence suggests that this procedure should be limited to large-volume cystic lesions or salvage procedures.? Autologous chondrocyte implantation techniques require a two-stage procedure, the first for chondrocyte harvest and the second for implantation in a periosteum-covered or matrix-induced form after in vivo culture expansion. Theoretically, the transplantation of chondrocyte-like cells into the defect will result in hyaline-like repair tissue.

Murawski CD; Kennedy JG

2013-06-01

28

Slope Stability  

Science.gov (United States)

This activity introduces students to the concept of slope stability (or angle of repose). Using an apparatus they have constructed, the students will work in small groups to test the stability angle of fine gravel, sand, and topsoil, gradually increasing the angle of the apparatus until the test material begins to slide off (angle of first fall) and until all the material slides away (angle of total fall). They will record these values and note which materials held the steepest slopes. As an extension, they can mix the test materials and observe the effects of mixing grain sizes. A student worksheet and discussion questions are provided.

29

Talocalcaneal transfixation in total dislocation of the talus and subtalar dislocations.  

Science.gov (United States)

We present 4 cases of talus dislocation. In one case we had open total lateral dislocation of the talus and in 3 other cases we had closed subtalar dislocation (disruption of the talocalcaneal and talonavicular joints). Reposition of the dislocation was made and talocalcaneal transfixation completed with 3 Kirschner wires, placed like a spread fan, under fluoroscopic control. Reoccurring dislocations were not experienced nor were there signs of avascular necrosis in these 4 cases. PMID:19354102

Pavi?, Roman

2009-03-01

30

Talocalcaneal transfixation in total dislocation of the talus and subtalar dislocations.  

UK PubMed Central (United Kingdom)

We present 4 cases of talus dislocation. In one case we had open total lateral dislocation of the talus and in 3 other cases we had closed subtalar dislocation (disruption of the talocalcaneal and talonavicular joints). Reposition of the dislocation was made and talocalcaneal transfixation completed with 3 Kirschner wires, placed like a spread fan, under fluoroscopic control. Reoccurring dislocations were not experienced nor were there signs of avascular necrosis in these 4 cases.

Pavi? R

2009-03-01

31

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)

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.

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

2009-07-01

32

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.

2009-01-01

33

WEIGHT OF CALCANEUM AND TALUS FOR DETERMINATION OF SEX  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Talus & Calcaneum are involved in the transmissionof body weight to the ground, considerable variation in the morphological features and weight of these bones havebeen reported by various authors. Objectives: To determine the importance of bone weight as a discriminative factorin identification of sex. Material and Method: 198 calcanei and 150 tali from Anatomy department of Quaid-e-AzamMedical College Bahawalpur were selected for the study. Mean weight of male & female bones on right & left side weredetermined. To increase the efficacy of the results they were statistically reevaluated by applying ±3SD anddetermining a calculated range. From this range, D.P. or demarcating points were established. Results: Bones of theright side were found to be heavier than those of the left side; also the mean weights of the male bones were greaterthan those of the female bones. On applying D.P.s it was possible to identify sex with greater accuracy than with othermetrical criteria. Conclusion: These findings suggest that weight of tarsal bones is a useful metrical feature for sexdetermination.

RIAZ AHMAD

2006-01-01

34

Magnetic resonance imaging features of osteochondral lesions of the talus.  

UK PubMed Central (United Kingdom)

BACKGROUND: Osteochondral lesions of the talus (OLT) traditionally have been thought to occur anterolaterally or posteromedially. Recent studies utilizing magnetic resonance imaging (MRI) have questioned this teaching. The purpose of this study was to use MRI to describe the location, frequency, and morphology of OLT and determine if any correlations exist between lesion location and other data points. METHODS: The location, frequency, and size of OLT based on a nine-zone grid were recorded on 77 MRI examinations. Lateral ligaments were inspected for evidence of injury. Stability of the lesions was assessed based on four MRI criteria: presence or absence of cartilage defects, edema-like signal abnormality, T2 bright rim, and/or subchondral cysts. Demographic data including patient age, injury mechanism, and chronicity were recorded. An ANOVA model was used to determine if statistical differences existed between lesion size and location. Pearson correlation coefficients were used to examine any association between lesion location and demographic data. RESULTS: Most of the lesions were located medially and centrally on the talar dome (54.5%), with the second highest frequency found laterally and centrally (31.2%). With the numbers available there was no statistical difference between the size of the lesions based on location. No strong correlations were found between lesion location and demographic data. CONCLUSION: This study refutes traditional teachings regarding the location of OLT and supports recent studies showing that most lesions are located medially and centrally on the talar dome.

Hembree WC; Wittstein JR; Vinson EN; Queen RM; Larose CR; Singh K; Easley ME

2012-07-01

35

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.)

2004-01-01

36

Mid-term results of one-stage surgical correction of congenital vertical talus.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Congenital vertical talus is a rare condition but a well-known cause of severe rigid flatfoot in children. The aim of this study was to evaluate the mid-term clinical and radiological results of one-stage surgical correction in children with congenital vertical talus. METHODS: Five feet in three children diagnosed with congenital vertical talus who had undergone surgical correction were followed up for a mean period of seven and half years. During this period they were clinically evaluated for subjective complaints and objective findings focused on the range of movement at the ankle joint, position of the hindfoot, and weight-bearing ability of the treated extremity. They were also evaluated on the basis of radiographs of foot and ankle made in standard projections. RESULTS: All the children had a good functional range of movement and normally shaped foot. The range of movement remains restricted and decreased during the follow-up period without causing any functional disability. All radiological measurements were within normal limits. There was no evidence of necrosis of talus. CONCLUSION: We recommend operative treatment for congenital vertical talus by the end of first year of age. The range of movement remains restricted and seems to decrease during follow-up, which had a little effect on the functional outcome of the ankle joint (Fig. 3, Tab. 1, Ref. 18). Full Text (Free, PDF) www.bmj.sk.

Mathew PG; Sponer P; Karpas K; Shaikh HH

2009-01-01

37

Absence of HOXD10 mutations in idiopathic clubfoot and sporadic vertical talus.  

Science.gov (United States)

The genetic etiology of idiopathic clubfoot is unknown. There have been cases reported in which both clubfoot and vertical talus appears in the same family; therefore, the genes responsible for vertical talus are reasonable candidates for idiopathic clubfoot. A mutation in HOXD10 was previously identified in a family with isolated congenital vertical talus. To determine whether HOXD10 is involved in the etiology of idiopathic clubfoot, HOXD10 coding and 5' and 3' untranslated regions were resequenced in 190 patients (177 with clubfoot, 10 with sporadic vertical talus, and 3 with both clubfoot and vertical talus), and 160 ethnically matched control subjects. Rare nonsynonymous HOXD10 amino acid substitutions (Leu154Val, Asn202Lys, and Thr175Ala), likely benign variants, were all detected once in patients and control subjects. Nucleotide substitutions were also identified in HOXD10 intronic and 3' untranslated regions, but were not more frequent in cases compared to controls. To investigate the possibility that unsequenced regulatory regions play a role in this disorder, we performed linkage analysis with markers on chromosome 2q near HOXD10 in one large family. We found no evidence of linkage near the HOXD gene cluster on chromosome 2q, suggesting genes other than HOXD10 are responsible for idiopathic clubfoot. PMID:17417092

Gurnett, Christina A; Keppel, Cassie; Bick, Jennifer; Bowcock, Anne M; Dobbs, Matthew B

2007-09-01

38

[Navigated retrograde drilling in Osteochondrosis dissecans (OCD) of the talus].  

UK PubMed Central (United Kingdom)

OBJECTIVE: Subchondral decompression and revascularization in Osteochondrosis dissecans (OCD) of the talus with cartilage preservation. INDICATIONS: Symptomatic talar OCD stage I and II, i.e., cartilage intact or almost intact. CONTRAINDICATIONS: Talar OCD stage III and IV, i.e., cartilage not intact. SURGICAL TECHNIQUE: Diagnostic ankle arthroscopy. Insertion of dynamic reference base (DRB) in the talar neck through a stab incision. After 3D image acquisition and planning of the drilling, navigated drilling with a 5 mm drill. Insertion of a 1 mm titanium wire into the canal and 3D image acquisition for evaluation of the canal. Autologous cancellous bone transplantation into the canal. Arthroscopic evaluation. POSTOPERATIVE MANAGEMENT: For 6 weeks, 15 kg partial weight bearing without immobilization. After 6 weeks full weight bearing. RESULTS: A total of 52 patients with symptomatic talar OCD stage I and II were included in a clinical follow-up study. Time needed for preparation, including the placement of the DRB, scanning time, and preparation of the trajectories was 7 min 32 s (4-30 min). In 50 cases (96%), the drilling was judged with 3D imaging to be correct. In the remaining 2 cases (4%), the drilling ended in the caudal portion of the lesion. A perforation of the cartilage was not registered arthroscopically. Follow-up after 12 months (range 6-36 months) was possible in 48 patients (92%). Three patients (6%) had been converted to bone cartilage transplantation (OATS) due to recurrent symptoms. These patients were excluded from follow-up. The follow-up scores were Visual Analogue Scale Foot and Ankle (mean 93 points [range 86-100 points]) and the SF 36 (standardized to 100 point maximum, 90 points [range 79-100 points]).

Richter M; Zech S

2011-12-01

39

Reef-sourced slope deposits, Holocene, Bahamas  

Energy Technology Data Exchange (ETDEWEB)

Observations and sampling to 350 m from a two-person submersible off Chub Cay, Berry Island, Bahamas, support the idea that the Holocene deep reef is a principal source of talus, now cemented, that foots the windward margins of Great Bahama Bank. At the Chub Cay dive site, a wall extends from 30 to 170 m subsea; below is a low-relief fore reef slope, ca. 50/sup 0/, of limestone veneered with sediment. The upper wall from 30 to 80 m, the deep reef, has a luxuriant growth of corals and a profusion of the calcareous alga halimeda spp. Below 50 m, living coral decreases, and from 80 to 170 m the wall is highly irregular with discontinuous ledges and blind-end caves. At depths from 150 to 170 m, the wall gives way to the fore reef slope whose relative smooth surface dips at 50/sup 0/ to 60/sup 0/ and extends to 350 m. The fore reef is limestone, but its topography resembles that of alluvial fans; rounded ridges rise a few meters above the intervening valleys that are tens of meters wide. The limestone surface has a discontinuous veneer of fine sediment and algal plates, and locally loose cobble and boulder-sized blocks of limestone. A sample of the limestone slope is of well-cemented coral clasts and skeletal sediment. They infer that the deep reef grows outward so rapidly that it caves periodically. The resulting debris bypasses the wall, but some is perched on the steep fore reef slope below where it is soon incorporated into the slope by submarine cementation.

Ginsburg, R.N.; Eberli, G.P.; Harris, P.M.; Slater, R.; Swart, P.K.

1987-05-01

40

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)

Full Text Available Abstract in portuguese 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, r (more) espectivamente. 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 orthopedic 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 evalua (more) tions, 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.

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

2012-01-01

 
 
 
 
41

[Neonatal osteomyelitis of the talus due to methicillin-resistant Staphylococcus epidermidis].  

UK PubMed Central (United Kingdom)

Acute osteomyelitis is a relatively rare disorder in the neonatal period, with considerable morbidity and mortality. Early diagnosis and prompt treatment are essential for a successful outcome. In this report we present a case of acute osteomyelitis of the talus due to methicillin-resistant Staphylococcus epidermidis, observed in a 30-day-old infant.

Pampinella D; Serra G; Giordano S; Dones P; Di Gangi M; Failla MC; Corsello G

2013-06-01

42

Osteochondrosis dissicans and osteoid osteoma - two disorders rarely seen together in the talus  

International Nuclear Information System (INIS)

A rare case is described where osteochondrosis dissicans and osteoid osteoma were encountered at the same time in the talus. These diseases have so far not been reported in the literature to occur in combined form and therefore required some time and effort to be diagnosed, using CT, MRT and scintigraphy as methods of diagnosis. (orig./MG).

1990-01-01

43

Simultaneous correction of congenital vertical talus and talipes equinovarus using the Ponseti method.  

Science.gov (United States)

Talipes equinovarus (clubfoot) and congenital vertical talus are commonly seen as isolated deformities in the newborn; however, the case that we described in this article entailed a classic talipes equino varus on the left and a calcaneovalgus on the right. Both deformities were successfully corrected with manipulation therapy and, ultimately, surgical release of the tendoAchillis. PMID:20797881

David, Michael G

2010-08-25

44

Simultaneous correction of congenital vertical talus and talipes equinovarus using the Ponseti method.  

UK PubMed Central (United Kingdom)

Talipes equinovarus (clubfoot) and congenital vertical talus are commonly seen as isolated deformities in the newborn; however, the case that we described in this article entailed a classic talipes equino varus on the left and a calcaneovalgus on the right. Both deformities were successfully corrected with manipulation therapy and, ultimately, surgical release of the tendoAchillis.

David MG

2011-07-01

45

Chondroblastoma of the talus: natural development over 9.5 years. Case report.  

UK PubMed Central (United Kingdom)

The spontaneous development of chondroblastoma was seen clinically and demonstrated radiologically in the talus of a 5.5-year-old boy. It was followed for 9.5 years before surgery was performed. Histological examination revealed typical features. This suggests that chondroblastomas may undergo very slow growth and development. The case is compared with 31 other chondroblastomas of the foot.

Ochsner PE; von Hochstetter AR; Hilfiker B

1988-01-01

46

Flake fracture of the talus - diagnosis and follow up study by direct radiologic magnification technique  

Energy Technology Data Exchange (ETDEWEB)

With regard to 26 cases with a flake fracture of the talus we could demonstrate that in selected cases the primary diagnosis of the lesion is easier, when the direct radiologic magnification technique is performed. This technique, however, should be mainly used for follow up studies after an operation or a conservative therapy.

Langer, M.; Langer, R.

1981-03-01

47

Green side slope structure  

UK PubMed Central (United Kingdom)

The utility model relates to a slope structure, in particular to a green slope structure for plants growing on slope. The slope structure of the utility model comprises a slope and a plurality of carriage bags. The carriage bags contain plants growing material, water absorbing material and plant seeds. A plurality of carriage bags containing plants growing material, water absorbing material and plant seeds are paved or stacked on the slope. The lines or adhesives (glue, concrete or the like) are utilized for connecting the carriage bags, which forms an integral for the carriage bags. The carriage bags are fixed on the slope through adhesives (glue, concrete or the like), which makes the carriage bags and the slope form an integral. The green slope structure for plants growing on slope of the utility model has a function of slope-protecting and greening.

ZHANG YUSHUN

48

Clinical and MRI results after microfracture of osteochondral lesions of the talus.  

UK PubMed Central (United Kingdom)

PURPOSE: Arthroscopic microfracture (AM) of osteochondral lesions of the talus is used to induce intrinsic refilling of the defect and reduce pain. The aim of this retrospective study was to investigate the clinical state after AM and the MRI outcome. METHODS: A total of 22 patients [10 women, 12 men, 31 years old (mean, 13-68 range)] treated for osteochondral lesions of the talus by AM were examined 2 years (median) postoperatively and pre- and postoperative MRI results compared. Swelling/effusion, articular constriction, joint pain, and range of motion restriction were documented. Clinical state was evaluated using the AOFAS hindfoot score. MRI was used to assess the size of the defect, presence of bone marrow edema, cysts and effusion, thickness of repair tissue, and integrity of the cartilage. RESULTS: In all but six cases, the defect was located at the medial shoulder of the talus. The postoperative AOFAS score at follow-up was 87.5 points (median 36-100 points range). Seven patients were free of pain, 11 had "mild, occasional" pain, 1 "moderate daily", and 3 "severe, almost always present" pain (AOFAS). The defect volume was significantly reduced from 377 mm(3) preoperatively (median, interquartile distance: 417 mm(3)) to 249 mm(3) postoperatively (median, IQD: 336 mm(3), p = 0.019, Wilcoxon). In 7 cases, the defect was completely filled, in 11 partially and in 4 only slightly. CONCLUSION: After AM of osteochondral lesions of the talus, 18 of 22 patients had no or mild, occasional pain at 2 years follow-up. On MRI, the lesion volume had been reduced and filling with repair tissue was found.

Kuni B; Schmitt H; Chloridis D; Ludwig K

2012-12-01

49

Groundwater flow and storage within an alpine meadow-talus complex  

Directory of Open Access Journals (Sweden)

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 (3 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.

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

2010-01-01

50

Talus measurements as a diagnostic tool for sexual dimorphism in Egyptian population.  

UK PubMed Central (United Kingdom)

Measurements of talus have been shown to be sexually dimorphic in South African blacks and whites and Prehistoric New Zealand Polynesians. Since several studies have demonstrated that discriminant function equations used to determine the sex of a skeleton are population specific, the purpose of the present study was to derive similar equation for the tali of Egyptians. The sample consisted of 110 tali (67 male & 43 female) whose age at death ranged between 20 and 60 years. The tali were obtained from Anatomy departments of Minia and Cairo Universities and also from Forensic Medicine department of Justice Office in Minia governates - Egypt. Twelve measurements were taken for every talus. Data were analyzed by SPSS version 16. All measurements showed significant sexual differences (P < 0.05) except calcaneus articular surface width and navicular articular surfaced width. Talar length was found to be the most sexual dimorphic (90.9%). Combination of talar length, talar width and neck width gave a percentage of accuracy of 85.5%. Finally, it is concluded that the talus of Egyptian population is useful for sex estimation.

Abd-elaleem SA; Abd-elhameed M; Ewis AA

2012-02-01

51

Talus measurements as a diagnostic tool for sexual dimorphism in Egyptian population.  

Science.gov (United States)

Measurements of talus have been shown to be sexually dimorphic in South African blacks and whites and Prehistoric New Zealand Polynesians. Since several studies have demonstrated that discriminant function equations used to determine the sex of a skeleton are population specific, the purpose of the present study was to derive similar equation for the tali of Egyptians. The sample consisted of 110 tali (67 male & 43 female) whose age at death ranged between 20 and 60 years. The tali were obtained from Anatomy departments of Minia and Cairo Universities and also from Forensic Medicine department of Justice Office in Minia governates - Egypt. Twelve measurements were taken for every talus. Data were analyzed by SPSS version 16. All measurements showed significant sexual differences (P < 0.05) except calcaneus articular surface width and navicular articular surfaced width. Talar length was found to be the most sexual dimorphic (90.9%). Combination of talar length, talar width and neck width gave a percentage of accuracy of 85.5%. Finally, it is concluded that the talus of Egyptian population is useful for sex estimation. PMID:22281214

Abd-elaleem, Shereen Abd-elhakim; Abd-elhameed, Mostafa; Ewis, Ashraf Abd-elazeem

2012-01-11

52

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Gigena, Leopoldo M.; Chung, Christine B.; Lektrakul, Nittaya; Pfirrmann, Christian W.A.; Sung, Mi Sook [Department of Radiology, University of California, San Diego, CA (United States); Resnick, Donald [Department of Radiology, University of California, San Diego, CA (United States); Department of Radiology, Veterans Affairs San Diego Healthcare System, CA (United States)

2002-04-01

53

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

International Nuclear Information System (INIS)

[en] 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.)

2002-01-01

54

Idiopathic transient osteoporosis of the talus: a cause for unexplained foot and ankle pain.  

Science.gov (United States)

A 53-year-old woman was investigated for several neoplastic, inflammatory, and infective conditions for her left foot, and ankle pain associated with swelling, which she developed unexpectedly without history of trauma or infection. Gross osteopenia in the talus raised the possibilities of several differential diagnoses, but a magnetic resonance imaging scan showed diffuse bone marrow edema in the talus. With negative infective and inflammatory markers, the condition was ultimately labeled as "transient osteoporosis." She was reassured and followed up regularly. At the end of 12 months, she was completely asymptomatic, and her radiograph and magnetic resonance images showed significant improvement, with a normal-appearing talus and ankle joint, and there was complete resolution of bone marrow edema. Although "transient osteoporosis" of the foot is an uncommon condition, clinicians should be aware of this. Unexplained foot pain, with osteopenic bone and diffuse bone marrow edema on magnetic resonance imaging scan, is a feature of this condition. However, the diagnosis is established once other causes are excluded. The condition is self-limiting, and watchful expectancy of a normal recovery is the mainstay of treatment. PMID:22608351

Limaye, Rajiv; Tripathy, Sujit Kumar; Pathare, Sanjay; Saeed, Kamran

2012-05-18

55

Idiopathic transient osteoporosis of the talus: a cause for unexplained foot and ankle pain.  

UK PubMed Central (United Kingdom)

A 53-year-old woman was investigated for several neoplastic, inflammatory, and infective conditions for her left foot, and ankle pain associated with swelling, which she developed unexpectedly without history of trauma or infection. Gross osteopenia in the talus raised the possibilities of several differential diagnoses, but a magnetic resonance imaging scan showed diffuse bone marrow edema in the talus. With negative infective and inflammatory markers, the condition was ultimately labeled as "transient osteoporosis." She was reassured and followed up regularly. At the end of 12 months, she was completely asymptomatic, and her radiograph and magnetic resonance images showed significant improvement, with a normal-appearing talus and ankle joint, and there was complete resolution of bone marrow edema. Although "transient osteoporosis" of the foot is an uncommon condition, clinicians should be aware of this. Unexplained foot pain, with osteopenic bone and diffuse bone marrow edema on magnetic resonance imaging scan, is a feature of this condition. However, the diagnosis is established once other causes are excluded. The condition is self-limiting, and watchful expectancy of a normal recovery is the mainstay of treatment.

Limaye R; Tripathy SK; Pathare S; Saeed K

2012-09-01

56

Clinical outcome and magnetic resonance imaging after osteochondral autologous transplantation in osteochondritis dissecans of the talus.  

UK PubMed Central (United Kingdom)

BACKGROUND: Osteochondral autologous transplantation (OAT) has been performed for years for osteochondritis dissecans of the knee with good clinical results. In osteochondritis dissecans of the talus, however, OAT represents a challenge to the orthopaedic surgeon as frequently malleolar osteotomy has to be performed for exposure of the talus and the harvesting of the osteochondral graft usually requires an arthrotomy of the knee. METHODS: In this study, we evaluated the clinical outcome of OAT in 32 patients (mean follow-up 29 months) by means of the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale, ankle pain on the visual analogue scale (VAS), HSS Patella Score, and magnetic resonance imaging (MRI) of the osteochondral graft. RESULTS: Median AOFAS score was 86, median ankle pain on VAS was 2.0, and median HSS Patella score was 95. Complications included 1 case of delayed wound healing and 1 case of nonunion of the malleolar osteotomy requiring revision surgery. MRI findings were abnormal in 14 out of 28 cases; however, with the numbers available in our study no correlation to clinical outcome could be detected. CONCLUSION: OAT in osteochondritis dissecans of the talus was a safe procedure with good clinical results. As abnormal MRI finding was not necessarily diagnostically conclusive, MRI might be of limited value in postoperative follow-up. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Woelfle JV; Reichel H; Javaheripour-Otto K; Nelitz M

2013-02-01

57

Carbonate and siliciclastic deposits on slope and abyssal floor Adjacent to southwestern Florida platform  

Energy Technology Data Exchange (ETDEWEB)

Three distinct carbonate deposits have been identified on the slope and adjacent sea floor of the Southwestern Florida platform: (1) reef talus, recognized by shape and location, found on the upper slope of the Yucatan Channel and also east of the Marquesas Keys; (2) hemipelagic sediments, with complex sigmoidoblique bed forms, filling the intervening gap between the channel and Keys and forming two lobes on the floor of the northern Florida Straits; and (3) turbidite deposits, with chaotic internal bed forms, covering siliciclastic Mississippi fan sediments at the base of the canyons in the Florida escarpment. The source of the talus, eroded and transported during the many storms which frequent the region, is the reef complexes which have formed on the platform rim. The sediment of the other two deposits is of foraminiferal tests, produced in nutrient-rich waters at the shelf edge. Geophysical, geochemical, and sedimentological data suggest that the spatial relationships of these deposits are related to sea level variations. During extreme lowstands, with much of the shelf exposed, the dominant sedimentation is siliciclastic deposition on the abyssal floor, and slope talus development at the edge of the shelf. During a subsequent rise in sea level, after carbonate production on the shelf is initiated, sediment is transported southward to the head of the canyons and funneled to the abyssal floor. Subsequent rising sea level shifts the axis of transport farther on the shelf, bypassing the canyons and funneling the sediment through breaks in the carbonate reef-banks at the southern edge of the platform. At the sites of both the hemipelagic and the turbidite deposition, high-resolution seismic data indicate that at least three cycles of deposition have occurred.

Holmes, C.W.

1983-03-01

58

Slopes of Tilings  

CERN Multimedia

We study here slopes of periodicity of tilings. A tiling is of slope if it is periodic along direction but has no other direction of periodicity. We characterize in this paper the set of slopes we can achieve with tilings, and prove they coincide with recursively enumerable sets of rationals.

Jeandel, Emmanuel

2010-01-01

59

Effect of Talus Deposit Excavations on Hydrogeochemical Characteristics of Kuvars Spring Water, Maltepe, Istanbul, Turkey  

Directory of Open Access Journals (Sweden)

Full Text Available Spring waters consumed for drinking purposes should be clean and quality. These waters with balanced mineral distribution, which do not contain organic substances, whose physical and chemical caharacteristics comply with certain quality parameters and which do not negatively affect human health are identified as healthy water. Kuvars water is a spring water which is pumped out from the draw well at the Camurluk stream basin of Maltepe province of Istanbul and filled into bottles. The Camurluk stream basin is approximately 4.5 km2. The Camurluk stream basin is sedimentary rocks and talus deposit outcrops. Reaching of trace elements, which is found more in the talus deposit samples than outcropping quartzarenite at the basin, to underground aquifer as ions under effect of rains, water rock interaction, leakage and filtration, is prevented by illite type clay levels existing within the talus deposit stack, which have upto 20 cm thickness. However, negative effects of the excavation that were made at the talus deposit reflect on the hydrologic cycle and chemical compositions of well waters. This effect was at first negatively affected the physical characteristics of the well waters. During the rainy periods, the water in the excavated area which was enriched with respect to the suspended sediments was percolated into the groundwaters from the joints and cracks of the quartzarenite. The turbidity value measured in the well waters of K2 and K3 were determined as 40.3 NTU and 34.2 NTU respectively. Although at the basin, the aquifer of underground water and the well waters being managed are quartzarenite, the fact that water types belonging to well waters differ (they are not same) according to the Piper diagram and when the heavy metal content of the water of well numbered KS1 is taken as basis, that some heavy metals such as Al3+, Fe2+, Ni2+, Mn2+ and Cu2+ be enriched 3 to 40 times in KS2 and KS3 well waters, are caused by talus deposit—water interaction at the excavation area. After a rainfall, in the water that became turbid with the water-talus deposit interaction at the excavation area, the water-mineral interaction has caused the limit value for drinking water suggested by World Health Organization (WHO) to be exceeded with the Al3+ concentration of 189 ppb detected in KS2 well water and Fe2+ concentration of 185 ppb has caused to approach the drinking water limit value of 200 ppb permitted by World Health Organization (WHO), United States Environmental Protection Agency (EPA), European Union (EU) and Turkish Standards (TS). Therefore, at the water basins where bottled spring waters consumed for drinking purposes are produced, technical undertakings that shall disturb the stability of geological units should not be permitted.

Rustem Pehlivan; Hasan Emre; Deniz Key

2012-01-01

60

Effect of graft height mismatch on contact pressures with osteochondral grafting of the talus.  

UK PubMed Central (United Kingdom)

BACKGROUND: Osteochondral allograft transplantation is technically demanding. It is not always possible to place the surface of the graft perfectly flush with the surrounding cartilage. One must often choose between placing at least some portion of the surface of the graft slightly elevated or recessed. The effect of this choice on joint contact pressure is unknown. PURPOSE: This study was undertaken to determine the effect of graft height mismatch on joint contact pressure in the ankle. STUDY DESIGN: Controlled laboratory study. METHODS: Ten human cadaveric ankles underwent osteochondral grafting by removal then replacement of an osteochondral plug. Six conditions were tested: intact, graft flush, graft elevated 1.0 mm, graft elevated 0.5 mm, graft recessed 0.5 mm, and graft recessed 1.0 mm. Joint contact pressures were measured with a Tekscan sensor while loads of 200 N, 400 N, 600 N, and 800 N were sequentially applied. RESULTS: The peak contact pressure at the graft site for the flush condition was not significantly different from the intact condition for either medial or lateral lesions. In contrast, peak pressure on the opposite facet of the talar dome was significantly increased during the flush condition for the medial but not the lateral grafts. Elevated grafts experienced significantly increased contact pressures, whereas recessed grafts experienced significantly decreased pressures. These changes were greater for lateral than for medial lesions. Reciprocal changes in joint contact pressures were found on the opposite facet of the talus with elevated grafts on the lateral side and recessed grafts on the medial side. CONCLUSION: Flush graft placement can restore near-normal joint contact pressure. Elevated graft placement leads to significant increases in joint contact pressure at the graft site. Recessed graft placement leads to a transfer of pressure from the graft site to the opposite facet of the talus. CLINICAL RELEVANCE: Osteochondral grafts in the talus should be placed flush if possible or else slightly recessed.

Latt LD; Glisson RR; Montijo HE; Usuelli FG; Easley ME

2011-12-01

 
 
 
 
61

Fluoroscopy-guided retrograde core drilling and cancellous bone grafting in osteochondral defects of the talus.  

UK PubMed Central (United Kingdom)

PURPOSE: In undetached osteochondral lesions (OCL) of the talus both revitalisation of the subchondral necrosis and cartilage preservation are essential. For these cases, we assess the results of minimally invasive retrograde core drilling and cancellous bone grafting. METHODS: Forty-one osteochondral lesions of the talus (12x grade I, 22x grade II and 7x grade III according to the Pritsch classification, defect sizes 7-14 mm) in 38 patients (mean age 33.2 years) treated by fluoroscopy-guided retrograde core drilling and autologous cancellous bone grafting were evaluated by clinical scores and MRI. The mean follow-up was 29.0 (±13) months. RESULTS: The AOFAS score increased significantly from 47.3 (±15.3) to 80.8 (±18.6) points. Lesions with intact cartilage (grades I and II) had a tendency to superior results than grade III lesions (83.1?±?17.3 vs. 69.4?±?22.2 points, p?=?0.07). First-line treatments and open distal tibial growth plates led to significantly better outcomes (each p?talus with intact cartilage grades I and II. However, second-line treatments and grade III lesions with cracked cartilage surface can not be generally recommended for this procedure.

Anders S; Lechler P; Rackl W; Grifka J; Schaumburger J

2012-08-01

62

Surgical treatment of osteochondritis dissecans of the talus: a systematic review.  

UK PubMed Central (United Kingdom)

PURPOSE: Osteochondritis dissecans (OCD) is an aseptic bone necrosis and represents pathology of high clinical relevance, which is frequently located on the talus. Various treatment strategies including non-surgical and surgical approaches have been described. An evidence-based treatment algorithm is still lacking. The present systematic review focuses on surgical treatment options and their stage-dependent outcome described for treatment of osteochondritis dissecans of the talus with special regard to the best available evidence. METHODS: For this purpose, an OVID-based systematic literature search was performed including the following databases; MEDLINE, MEDLINE preprints, EMBASE, CINAHL, Life Science Citations, British National Library of Health and Cochrane Central Register of Controlled trials (CENTRAL). Literature search period was from January 1967 up to December 2009. After applying study specific inclusion criteria (minimum follow-up 12 months, patient evaluation by standardized scoring systems, etc.), a total of 54 studies with clinical follow-up of 1,105 patients was included. Methodology of these studies was systematically analyzed by the means of the Coleman Methodology Score. Outcome and success rate was evaluated in dependence of surgical treatment applied and in dependence of the stage of disease. RESULTS: All 54 studies included were classified as evidence level IV representing case series. The average Coleman Methodology Score was 63 (SD ± 17) points. The average follow-up of the 1,105 patients was 47 months (SD ± 17) with a mean age of 29 (SD ± 5.6) years. The proportion of excellent and good treatment results was stage-independent in total 75 %. According to the criteria of the score applied for patient's evaluation in the individual study, the overall percentage of "good" and "excellent" clinical outcome in 869 patients was 79 %, and according the classification of Berndt and Harty, 82 % in stage I, 86 % in stage II, 83 % in stage III and 76 % in stage IV. CONCLUSIONS: Although OCD of the talus represents a frequently observed orthopedic pathology, evidence concerning operative treatment of osteochondrosis dissecans of the talus is still elusive. With over 1,100 included patients in the present study, no strong recommendations based upon scientific evidence can be given.

Zwingmann J; Südkamp NP; Schmal H; Niemeyer P

2012-09-01

63

Groundwater flow and storage within an alpine meadow-talus complex  

Directory of Open Access Journals (Sweden)

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.

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

2010-01-01

64

Why allograft reconstruction for osteochondral lesion of the talus? The osteochondral autograft transfer system seemed to work quite well.  

UK PubMed Central (United Kingdom)

Osteochondral lesions of the talus (OCLT) are a challenging entity despite the advancements that have been made to treat focal deficits of articular cartilage. Both autograft and allograft reconstruction have had documented success in the treatment of OLCT. Universal availability and known chondrocyte viability makes the osteochondral autograft transfer system (OATS) an excellent option for recurrent, deep, or moderate defects. For defects with a large diameter, large cystic component, or heavily involving the shoulder of the talus, an allograft provides an excellent option. This article focuses on the efficacy and determination of the most appropriate graft reconstruction: allograft reconstruction or OATS.

Kadakia AR; Espinosa N

2013-03-01

65

Associated lateral process and posteromedial tubercle talus fractures with entrapment of the medial neurovascular bundle: A case report.  

UK PubMed Central (United Kingdom)

This paper describes a case of an isolated fracture of the lateral process of the talus associated with a fracture in the posteromedial tubercle of the talus with entrapment of the medial neurovascular bundle. Currently no similar cases have been published describing this type of neurovascular bundle injury. Furthermore, in contrast to previously published cases, both fractures were treated surgically despite the absence of posteromedial tubercle fracture displacement. This article reviews the literature and provides useful recommendations for the clinical management of similar cases in the future.

Gómez Robledo J

2013-08-01

66

The shape and presentation of the Catarrhine talus: a geometric morphometric analysis.  

UK PubMed Central (United Kingdom)

The distal component of the talo-crural joint, the talus, was compared, using geometric morphometrics, in 219 specimens from nine extant taxa to identify differences in shape and the factors influencing them. The specimens were laser scanned, digitally reconstructed, and landmarked. The whole talus, proximal and distal articular facet subgroups were analyzed using Generalized Procrustes analysis, linear regression, principal component analysis, analysis of percent variance, dot-product vector analysis, and pair-wise permutation tests to evaluate shape, and were visualized by TPS deformation of an exemplar surface. Significant percentages of shape variation among taxa were due to body mass, talar size, superfamily, and substrate preference. Shape and presentational morphology associated with these factors were documented, along with the similarities and differences among individual taxa. Nearly all taxa were significantly different in overall, proximal and distal shapes. The most important factors influencing whole talar shape were log centroid size and substrate preference. Substrate preference was also the most important factor defining proximal articular morphology and unrelated to other factor such as mass, while distal articular morphology was influenced by superfamily (head angle and shape). Results demonstrated that substrate preference and superfamily significantly influenced distal presentation, while substrate preference influenced proximal articular shape.

Turley K; Frost SR

2013-06-01

67

Dynamic US study in the evaluation of infants with vertical or oblique talus deformities.  

UK PubMed Central (United Kingdom)

BACKGROUND: Congenital vertical talus (CVT) is a rare foot deformity that is sometimes difficult to differentiate from oblique talus (OT) by physical examination and foot radiography. OBJECTIVE: The purpose of this study was to summarize our experience with US in evaluation of CVT and OT deformities. MATERIALS AND METHODS: We identified all children (2005-2011) younger than 6 months who underwent dynamic focused US of the foot at our tertiary-care facility to evaluate clinically equivocal cases of CVT. Diagnostic criteria for CVT were persistent talonavicular dislocation on forced plantar flexion of the foot. OT was diagnosed based on reduction of the talonavicular dislocation on forced plantar flexion. Medical and imaging charts were reviewed for diagnosis on US and plain radiographs (when available) and for underlying neuromuscular disorders, treatment and outcome on follow-up. RESULTS: Ten patients (eight boys and two girls, mean age 33 days) were evaluated by US for CVT. Radiographs of the foot were obtained in only two children and were non-diagnostic. Thirteen feet were evaluated by US. Diagnosis of CVT was confirmed by surgery in seven children, three of whom had bilateral CVT. Diagnosis of OT in three children was supported by response to casting treatment. CONCLUSION: Dynamic US can reliably distinguish between CVT and OT deformities.

Supakul N; Loder RT; Karmazyn B

2013-03-01

68

Direction of the oblique medial malleolar osteotomy for exposure of the talus.  

UK PubMed Central (United Kingdom)

INTRODUCTION: A medial malleolar osteotomy is often indicated for operative exposure of posteromedial osteochondral defects and fractures of the talus. To obtain a congruent joint surface after refixation, the oblique osteotomy should be directed perpendicularly to the articular surface of the tibia at the intersection between the tibial plafond and medial malleolus. The purpose of this study was to determine this perpendicular direction in relation to the longitudinal tibial axis for use during surgery. MATERIALS AND METHODS: Using anteroposterior mortise radiographs and coronal computed tomography (CT) scans of 46 ankles (45 patients) with an osteochondral lesion of the talus, two observers independently measured the intersection angle between the tibial plafond and medial malleolus. The bisector of this angle indicated the osteotomy perpendicular to the tibial articular surface. This osteotomy was measured relative to the longitudinal tibial axis on radiographs. Intraclass correlation coefficients (ICC) were calculated to assess reliability. RESULTS: The mean osteotomy was 57.2 ± 3.2° relative to the tibial plafond on radiographs and 56.5 ± 2.8 on CT scans. This osteotomy corresponded to 30.4 ± 3.7° relative to the longitudinal tibial axis. The intraobserver (ICC, 0.90-0.93) and interobserver (ICC, 0.65-0.91) reliability of these measurements were good to excellent. CONCLUSION: A medial malleolar osteotomy directed at a mean 30° relative to the tibial axis enters the joint perpendicularly to the tibial cartilage, and will likely result in a congruent joint surface after reduction.

van Bergen CJ; Tuijthof GJ; Sierevelt IN; van Dijk CN

2011-07-01

69

Mosaicplasty for osteochondral lesions of the talus: a report of two cases.  

UK PubMed Central (United Kingdom)

Two women (24 and 27 years old) noted pain in the affected ankle of several years' duration. Radiography and magnetic resonance imaging revealed osteochondral lesions of the talus in both patients. The lesion sites measured 1.3 × 1.0 × 0.4 cm (0.52 cm(3)) and 2.0 × 1.9 × 0.5 cm (1.9 cm(3)). Each patient received a medial malleolar osteotomy with mosaicplasty. Donor plugs were obtained from the ipsilateral knee in both patients. Surgery was performed successfully in both patients without complications. At 2-year follow-up, both patients had recovered good ankle function, with no donor site morbidity. American Orthopedic Foot and Ankle Society ankle/hindfoot scores improved in the affected ankles from 16 to 84 in case 1 and from 43 to 87 in case 2. Mosaicplasty is effective in treating stage III or IV osteochondral lesions of the talus and results in good-to-excellent recovery of function.

Chiang C; Au MK

2013-01-01

70

Roadheader drives two slopes  

Energy Technology Data Exchange (ETDEWEB)

The paper reports the use of a heavy-duty roadheader to drive two slopes from operating coal mines to an underlying seam in Kentucky. Working for 3 shifts a day, 7 days a week, the slopes were completed in half the time that it would have taken using the conventional drill-and-blast method.

Brezovec, D.

1983-08-01

71

Heterogeneity of Holocene clinothems: Significance for the exploitation of ancient slope deposits  

Energy Technology Data Exchange (ETDEWEB)

Inclined margin deposits (clinothems) of ancient carbonate platforms and reef complexes are known to be important hydrocarbon reservoirs and may function as conduits for the migration of oil from basin to reef. Recent work in the Tongue of the Ocean (TOTO), Bahamas, provides new insight into the depositional anatomy of Holocene clinothems. Observations from 94 dives in a research submersible in the TOTO indicates that modern carbonate slopes of 30-40{degree} are forming by the synsedimentary amalgamation of linear trains of sediment and talus blocks derived from the margin of the platform. Sand-sized sediment is transported downslope by various gravity induced mechanisms and deposited in topographic lows between linear ridges where it is rapidly lithified by submarine cementation. These sediment lobes are decimeters thick, and extend across and down the slope for a few meters and tens of meters, respectively. Repeated episodes of deposition and cementation result in the amalgamation of individual sediment packages that are linear in shape and discontinuous in both lateral and vertical dimensions along the slope. Progressive slope accretion of this nature will result in a heterogeneous texture and composition, further complicated by a complex internal facies geometry. Awareness of the internal heterogeneity of modern slope deposits may be a critical factor when evaluating the potential of ancient slope deposits to act as conduits for the migration of hydrocarbons or to be economically viable reservoirs.

Grammer, G.M.; Ginsburg, R.N.; McNeill, D.F. (Univ. of Miami, FL (USA))

1990-05-01

72

Primary outcomes of the congenital vertical talus correction using the Dobbs method of serial casting and limited surgery.  

UK PubMed Central (United Kingdom)

INTRODUCTION: The traditional treatment for congenital vertical talus, which involves serial casting and extensive soft-tissue releases, has been associated with severe stiffness and other complications in adolescents and adults. Our hypothesis is that favorable results will be obtained using the Dobbs method of serial manipulation, casting, and limited surgery for vertical talus correction, even in older children and syndromic cases. Therefore, the present study aimed at evaluating the Dobbs method in such cases. MATERIALS AND METHODS: We treated 15 feet of 10 patients (aged from 1 month to 9 years) using manipulation and serial casting or the reverse Ponseti method followed by percutaneous Achilles tenotomy and limited open reduction of the talonavicular joint. All patients were evaluated both clinically and radiologically in a mean follow-up period of 2 years. RESULTS: After 2 years, all patients had plantigrade and flexible feet with good radiographic correction. The mean talocalcaneal angle before (70.5° ± 10.5) and after (31° ± 5.2) treatment and the talar axis metatarsal base angle before (60° ± 11.4) and after (15° ± 6.7) treatment were significantly improved (P < 0.001). DISCUSSION: Recent research has shown that manipulation and serial casting followed by limited surgery (Dobbs method) was successful in treating idiopathic congenital vertical talus. Our results also showed that this method resulted in an excellent outcome in both idiopathic and syndromic congenital vertical talus, even in older children.

Aslani H; Sadigi A; Tabrizi A; Bazavar M; Mousavi M

2012-08-01

73

Geotechnical slope analysis  

CERN Multimedia

Freshly updated and extended version of Slope Analysis (Chowdhury, Elsevier, 1978). This reference book gives a complete overview of the developments in slope engineering in the last 30 years. Its multi-disciplinary, critical approach and the chapters devoted to seismic effects and probabilistic approaches and reliability analyses, reflect the distinctive style of the original. Subjects discussed are: the understanding of slope performance, mechanisms of instability, requirements for modeling and analysis, and new techniques for observation and modeling. Special attention is paid to the relati

Chowdhury, Robin

2010-01-01

74

Slope Stability Monitoring  

UK PubMed Central (United Kingdom)

GPS multipath has long beenconsidered a major error source in GPSapplications. In this paper, however, an attemptis made to use multipath as a signal. The proposedapplication of using GPS multipath to monitorthe slope stability involves two steps. The firststep is to extract multipath and to detect itschange based on an adaptive filter using the leastmean-square algorithm. In the second step, themathematical models for slope stabilitymonitoring using the change of GPS multipatheffects have been established. In addition to themonitoring of slope stability, this techniqueprovides an easy-to-implement quality assurrancetool for CGPS antenna environment sensing afterdisasters such as typhoons, cyclones, andearthquakes.

Linlin Ge; Chris Rizos

75

Rock slope stability  

CERN Multimedia

Whether you're involved in surface mine design, surface mine production, construction, education, or regulation, this is an important book for your library. It describes the basic rock slope failure modes and methods of analysis--both kinematic and kinetic techniques. Chapters include geotechnical and geomechanical analysis techniques, hydrology, rock slope stabilization techniques, and geotechnical instrumentation and monitoring. Numerous examples, drawings, and photos enhance the text.

Kliche, Charles A

1999-01-01

76

A sloping gas duct  

International Nuclear Information System (INIS)

The sloping gas duct of the THTR-300 MWe reactor connects the hot gas collection space to the steam raising unit. A sloping perforated plate is provided to even out the speed and temperature distribution at the angle. The perforated plate has circular holes, which are distributed on a regular grid. The perforated plate is made of metal or ceramic material. The free cross-section is at least 50%. (DG)

1980-01-01

77

Narrowing the critical region for congenital vertical talus in patients with interstitial 18q deletions.  

UK PubMed Central (United Kingdom)

Interstitial deletions of 18q lead to a number of phenotypic features, including multiple types of foot deformities. Many of these associated phenotypes have had their critical regions narrowly defined. Here we report on three patients with small overlapping deletions of chromosome 18q determined by microarray analysis (chr18:72493281-73512553 hg19 coordinates). All of the patients have congenital vertical talus (CVT). Based on these findings and previous reports in the literature and databases, we narrow the critical region for CVT to a minimum of five genes (ZNF407, ZADH2, TSHZ1, C18orf62, and ZNF516), and propose that TSHZ1 is the likely causative gene for CVT in 18q deletion syndrome.

Mark PR; Radlinski BC; Core N; Fryer A; Kirk EP; Haldeman-Englert CR

2013-05-01

78

Narrowing the critical region for congenital vertical talus in patients with interstitial 18q deletions.  

Science.gov (United States)

Interstitial deletions of 18q lead to a number of phenotypic features, including multiple types of foot deformities. Many of these associated phenotypes have had their critical regions narrowly defined. Here we report on three patients with small overlapping deletions of chromosome 18q determined by microarray analysis (chr18:72493281-73512553 hg19 coordinates). All of the patients have congenital vertical talus (CVT). Based on these findings and previous reports in the literature and databases, we narrow the critical region for CVT to a minimum of five genes (ZNF407, ZADH2, TSHZ1, C18orf62, and ZNF516), and propose that TSHZ1 is the likely causative gene for CVT in 18q deletion syndrome. PMID:23495172

Mark, Paul R; Radlinski, Brian C; Core, Nathalie; Fryer, Alan; Kirk, Edwin P; Haldeman-Englert, Chad R

2013-03-13

79

Indications and limitations of osteochondral autologous transplantation in osteochondritis dissecans of the talus.  

UK PubMed Central (United Kingdom)

PURPOSE: Osteochondral autologous transplantation (OAT) from the ipsilateral femoral lateral condyle in osteochondritis dissecans (OD) of the talus has shown good clinical results in the past. To further define, indications and limitations of OAT various factors have been discussed which might influence the clinical outcome. METHODS: In this study, the clinical outcome of OAT of 32 patients (mean follow-up 29 months) was evaluated by means of the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale, ankle pain on the visual analogue scale (VAS), and Hospital for Special Surgery (HSS) Patella score. We then analysed the statistical correlation between clinical outcome and various variables such as age, pre-existing osteoarthritis, or size of the lesion. RESULTS: Median AOFAS score was 86 (range 68-100), median ankle pain on VAS was 2.0 (range 0-5.5), and median HSS Patella score was 95 (range 35-100). Advanced age (above 40 years of age) was associated with a significantly lower HSS Patella score (80 vs. 97.5, p = 0.035). None of the other variables (obesity, pre-existing osteoarthritis, size of the lesion, necessity of malleolar osteotomy, localization of the lesion, and number of previous surgeries) influenced the clinical outcome adversely. CONCLUSIONS: Osteochondral autologous transplantation in OD of the talus is a safe procedure with good clinical results. As advanced age is associated with higher donor-site morbidity, indication for OAT in older patients should be carefully considered. As none of the other variables affected the clinical outcome of OAT adversely, there is no contraindication for OAT, for example, in osteochondral lesions requiring more than one osteochondral grafts, lateral lesions, patients with BMI >25, pre-existing osteoarthritis, or failed previous surgery. LEVEL OF EVIDENCE: IV.

Woelfle JV; Reichel H; Nelitz M

2013-08-01

80

Linear Functions and Slope  

Science.gov (United States)

This session on linear function and slope contains five parts, multiple problems and videos, and interactive activities geared to help students recognize and understand linear relationships, explore slope and dependent and independent variables in graphs of linear relationships, and develop an understanding of rates and how they are related to slopes and equations. Throughout the session, students use spreadsheets to complete the work, and are encouraged to think about the ways technology can aid in teaching and understanding. The solutions for all problems are given, and many allow students to have a hint or tip as they solve. There is even a homework assignment with four problems for students after they have finished all five parts of the session.

2008-03-06

 
 
 
 
81

Slope Stability Analysis Program  

Science.gov (United States)

This site provides information as well as a downloadable demo version of a slope stability and reinforced soil analysis and design software. The software includes an analysis option which analyzes strata profile and groundwater conditions, surcharge loads and earthquake forces, slip surfaces, and reinforced soil options. Data input and editing can also be performed as well as output from the program and graphics.

2008-07-17

82

A platyrrhine talus from the early Miocene of Peru (Amazonian Madre de Dios Sub-Andean Zone).  

Science.gov (United States)

The earliest platyrrhines have been documented from the late Oligocene of Bolivia (Salla) and from the early and early middle Miocene of middle and high latitudes (central Chile and Argentinean Patagonia). Recent paleontological field expeditions in Peruvian Amazonia (Atalaya, Cusco; Upper Madre de Dios Basin) have led to the discovery of a new early Miocene locality termed MD-61 ('Pinturan' biochronological unit, ~18.75-16.5 Ma [millions of years ago]). Associated with the typical Pinturan dinomyid rodent Scleromys quadrangulatus, we found a well-preserved right talus of a small-bodied anthropoid primate (MUSM-2024). This new platyrrhine postcranial element displays a combination of talar features primarily found among the Cebidae, and more especially in the Cebinae. Its size approximates that of the talus of some living large marmosets or small tamarins (Cebidae, Callitrichinae). MUSM-2024 would thus document a tiny Saimiri-like cebine, with the body size of a large marmoset. Functionally, the features and proportions of MUSM-2024 indicate that this small primate was arboreal and primarily quadrupedal, agile, with frequent horizontal leaping and vertical clinging in its locomotor repertoire. This small talus is the first platyrrhine fossil to be found from Peru and the earliest primate fossil from northern South America. This new early Miocene taxon could be a stem cebid, thereby providing new evidence on the existence of some long-lived clades of modern platyrrhines. PMID:22974538

Marivaux, Laurent; Salas-Gismondi, Rodolfo; Tejada, Julia; Billet, Guillaume; Louterbach, Mélanie; Vink, Jochem; Bailleul, Julien; Roddaz, Martin; Antoine, Pierre-Olivier

2012-09-10

83

A platyrrhine talus from the early Miocene of Peru (Amazonian Madre de Dios Sub-Andean Zone).  

UK PubMed Central (United Kingdom)

The earliest platyrrhines have been documented from the late Oligocene of Bolivia (Salla) and from the early and early middle Miocene of middle and high latitudes (central Chile and Argentinean Patagonia). Recent paleontological field expeditions in Peruvian Amazonia (Atalaya, Cusco; Upper Madre de Dios Basin) have led to the discovery of a new early Miocene locality termed MD-61 ('Pinturan' biochronological unit, ~18.75-16.5 Ma [millions of years ago]). Associated with the typical Pinturan dinomyid rodent Scleromys quadrangulatus, we found a well-preserved right talus of a small-bodied anthropoid primate (MUSM-2024). This new platyrrhine postcranial element displays a combination of talar features primarily found among the Cebidae, and more especially in the Cebinae. Its size approximates that of the talus of some living large marmosets or small tamarins (Cebidae, Callitrichinae). MUSM-2024 would thus document a tiny Saimiri-like cebine, with the body size of a large marmoset. Functionally, the features and proportions of MUSM-2024 indicate that this small primate was arboreal and primarily quadrupedal, agile, with frequent horizontal leaping and vertical clinging in its locomotor repertoire. This small talus is the first platyrrhine fossil to be found from Peru and the earliest primate fossil from northern South America. This new early Miocene taxon could be a stem cebid, thereby providing new evidence on the existence of some long-lived clades of modern platyrrhines.

Marivaux L; Salas-Gismondi R; Tejada J; Billet G; Louterbach M; Vink J; Bailleul J; Roddaz M; Antoine PO

2012-11-01

84

Fragmentation of the proximal tubercle of the talus in horses: 9 cases (2004-2010).  

UK PubMed Central (United Kingdom)

OBJECTIVE: To identify the prevalence of fragmentation of the proximal tubercle of the talus (FPTT) in a hospital population of horses, characterize the anatomic features of the affected area and fragments, and describe clinical findings, diagnosis, treatment, and outcome for horses with FPTT. DESIGN: Retrospective case series. ANIMALS: 9 horses with FPTT. PROCEDURES: 2,543 radiographic views of the tarsal region of 1,526 horses that were evaluated between June 2004 and December 2010 were reviewed. Medical case records for horses with detectable FPTT were retrieved, and signalment, history, clinical signs, diagnostic methods, treatment, and outcome were recorded for assessment. RESULTS: 9 horses (median age, 5 years; age range, 1 to 12 years) with FPTT were identified. Seven horses were warmbloods. Diagnosis was made on the basis of radiographic findings, occasionally along with results of ultrasonography and CT. The only horse that was lame in the affected limb had a history of a prior traumatic event and resultant lateral tibial malleolus fracture. One horse underwent arthroscopy, but fragments were not found and were presumed to be extra-articular. Outcome was available for 7 horses; mean ± SD duration of stable radiographic and clinical examination findings was 3 ± 1 years (range, 1 to 4 years). CONCLUSIONS AND CLINICAL RELEVANCE: FPTT appeared to occur more frequently in warmbloods and was not usually associated with lameness. Affected horses remained clinically and radiographically stable over time. These data have provided some information regarding the importance of FPTT for practitioners who perform radiographic screenings during prepurchase examinations.

Espinosa P; Lacourt M; Alexander K; David F; Laverty S

2013-04-01

85

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2003-07-01

86

Modified step-cut medial malleolar osteotomy for osteochondral grafting of the talus.  

UK PubMed Central (United Kingdom)

BACKGROUND: Osteochondral grafting for the treatment of osteochondral lesions of the talus (OLT) usually requires a medial malleolar osteotomy (MMO) to achieve adequate intraarticular exposure. This study describes the technique used and the results obtained using a modified step-cut MMO for osteochondral grafting of talar dome lesions. MATERIALS AND METHOD: Eleven feet in ten patients underwent modified step-cut MMO prior to osteochondral grafting for OLT. The patients included three women and seven men with a mean age of 40 (range, 20 to 51) years. Modified step-cut MMO consisted of an oblique osteotomy, which was made at approximately 45 degrees to the transverse plane of the proposed traditional step-cut osteotomy, and a vertical osteotomy to the axilla on the medial tibial plafond. RESULTS: In all patients, modified step-cut MMO provided better perpendicular access to lesions than traditional step-cut osteotomy. In all cases, the osteochondral graft plug was accurately set perpendicular to the defect area, and all ten patients experienced uncomplicated osteotomy healing at a mean 8 weeks postoperatively without loss of reduction or malreduction. CONCLUSION: Modified step-cut MMO is an excellent, reproducible method for perpendicular access to a talar dome lesion.

Lee KB; Yang HK; Moon ES; Song EK

2008-11-01

87

Effect of simulated lateral process talus "fracture excision" on its ligamentous attachments.  

UK PubMed Central (United Kingdom)

Recent epidemiologic studies highlight lateral talar process fractures as snowboarder's fracture or snowboarder's ankle. Snowboarding is the fastest growing sport worldwide, so lateral talar process fractures are increasing in frequency and mandating a more careful assessment of injury patterns, surrounding tissue involvement, and treatment strategy. In this study, we evaluated the effects of lateral talar process fracture on the footprints of 3 lateral stabilizing ligaments of the ankle and subtalar joint-the lateral talocalcaneal ligament (LTCL), the anterior talofibular ligament (ATFL), and the posterior talofibular ligament (PTFL). The musculotendinous structures from 10 fresh cadaveric limbs were removed and the distal fibula reflected to provide visualization of the lateral talar process and ligamentous attachments. Length and width of the LTCL, ATFL, and PTFL footprints on the lateral process of the talus were measured with calipers before and after removal of a 1-cm(3) simulated fracture fragment. Relative changes in the attachment site areas for the 3 ligaments were determined. Mean pre-excision footprint areas were 80.57 mm(2) (LTCL), 224.38 mm(2) (ATFL), and 394.18 mm(2) (PTFL); mean postexcision footprint areas were 2.10 mm(2) (LTCL), 194.89 mm(2) (ATFL), and 335.18 mm(2) (PTFL); and mean decreases calculated as percentages of the original areas were 97.5% +/- 3.5% (LTCL), 11.7% +/- 13.0% (ATFL), and 14.3% +/- 12.3% (PTFL). Removal of a 1-cm(3) bony fragment from the lateral talar process involves 3 of the major lateral stabilizing ligaments: approximately 100% of LTCL and approximately 10% to 15% of ATFL and PTFL.

Langer P; Nickisch F; Spenciner D; DiGiovanni C

2009-05-01

88

Effect of simulated lateral process talus "fracture excision" on its ligamentous attachments.  

Science.gov (United States)

Recent epidemiologic studies highlight lateral talar process fractures as snowboarder's fracture or snowboarder's ankle. Snowboarding is the fastest growing sport worldwide, so lateral talar process fractures are increasing in frequency and mandating a more careful assessment of injury patterns, surrounding tissue involvement, and treatment strategy. In this study, we evaluated the effects of lateral talar process fracture on the footprints of 3 lateral stabilizing ligaments of the ankle and subtalar joint-the lateral talocalcaneal ligament (LTCL), the anterior talofibular ligament (ATFL), and the posterior talofibular ligament (PTFL). The musculotendinous structures from 10 fresh cadaveric limbs were removed and the distal fibula reflected to provide visualization of the lateral talar process and ligamentous attachments. Length and width of the LTCL, ATFL, and PTFL footprints on the lateral process of the talus were measured with calipers before and after removal of a 1-cm(3) simulated fracture fragment. Relative changes in the attachment site areas for the 3 ligaments were determined. Mean pre-excision footprint areas were 80.57 mm(2) (LTCL), 224.38 mm(2) (ATFL), and 394.18 mm(2) (PTFL); mean postexcision footprint areas were 2.10 mm(2) (LTCL), 194.89 mm(2) (ATFL), and 335.18 mm(2) (PTFL); and mean decreases calculated as percentages of the original areas were 97.5% +/- 3.5% (LTCL), 11.7% +/- 13.0% (ATFL), and 14.3% +/- 12.3% (PTFL). Removal of a 1-cm(3) bony fragment from the lateral talar process involves 3 of the major lateral stabilizing ligaments: approximately 100% of LTCL and approximately 10% to 15% of ATFL and PTFL. PMID:19584991

Langer, Phillip; Nickisch, Florian; Spenciner, David; DiGiovanni, Christopher

2009-05-01

89

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

Directory of Open Access Journals (Sweden)

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.

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

2009-01-01

90

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish 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 n (more) o 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 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 t (more) hree 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.

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

2009-04-01

91

Using Submarine Landslides to Predict Slope Stability  

Science.gov (United States)

Students use detailed bathymetric maps to find submarine landslides and compare the slope of these slides to the slope of hills near school and home. By comparing the slopes they can consider slope failure, especially during earthquakes.

Doan, Shawn

92

Quantifying Slope Stability Decrease In  

UK PubMed Central (United Kingdom)

To ensure the stability of a man-made slope in a rock or soil mass throughout its envisagedengineering lifetime, the decrease of relevant strength properties of the slope material has to betaken into account. Following the initial stress release after excavation, weathering and erosionprocesses will start acting upon the newly exposed slope material and as field data shows, thismay have a significant effect in less than one hundred years.

Huisman Marco; Hack Robert

93

A novel mutation in TNNT3 associated with Sheldon-Hall syndrome in a Chinese family with vertical talus.  

UK PubMed Central (United Kingdom)

Distal arthrogryposis (DA) is a group of rare, clinically and genetically heterogeneous disorders primarily characterized by congenital contractures of the limb joints. Recently, mutations in genes encoding the fast-twitch skeletal muscle contractile myofibers complex, including troponin I2 (TNNI2), troponin T3 (TNNT3), tropomyosine 2 (TPM2), and embryonic myosin heavy chain 3 (MYH3), and the slow-twitch skeletal muscle myosin binding protein C1 (MYBPC1) were confirmed to cause DA1, DA2A, and DA2B. DA2B, or Sheldon-Hall syndrome (SHS; MIM 601680), is intermediate to DA1 and DA2A, or Freeman-Sheldon syndrome (FSS; MIM193700), and shows prominent facial traits. This report describes a Chinese family with SHS over three generations in which all affected individuals showed vertical talus and one demonstrated preauricular tags on the face. Linkage analysis and PCR sequencing revealed a novel substitute mutation at a hot-spot site in TNNT3 (c.187C > T; p.R63C). This mutation was confirmed to cosegregate with the DA phenotype in affected individuals. SIFT and PolyPhen analyses suggest that the mutation is pathogenic. We report this mutation in TNNT3 and speculate that bilateral vertical talus, or severe clubfoot, might be a special characteristic for cases with the TNNT3 R63C mutation.

Zhao N; Jiang M; Han W; Bian C; Li X; Huang F; Kong Q; Li J

2011-05-01

94

[Osteochondrosis dissecans and osteochondral lesions of the talus: clinical and biochemical aspects].  

UK PubMed Central (United Kingdom)

BACKGROUND: The natural course of osteochondral lesions of the talus are varied and the disease pattern is not clearly defined. There is an ongoing discussion among clinicians concerning the aethiopathology and the correct treatment. METHODS: In this article all relevant studies are analysed with regard to aetiology, long-term outcome and the different established treatment options. Against the background of the current biomechanical understanding, an approach is made to this controversially discussed disease pattern utilising our own biomechanical laboratory results. RESULTS: The available literature deals with longitudinal analyses regarding the natural history of the disease, conservative treatment, surgical options like debridement and anterograde drilling, retrograde drilling, osteochondral transplantation and autologous chondrocyte transplantation (ACT). Biomechanical trials describe high loads in the anterolateral parts of the joint. In most of the published studies the average age of the patients is around 28 years, younger patients have more favourable outcomes compared to older ones. In children the highest rate of spontaneous and advantageous course of the disease can be expected. Around 75% of the published outcomes relating to surgical therapy are satisfactory while 10% of the patients will suffer from osteoarthritis in the long term. CONCLUSION: While the aetiopathology of the disease remains unclear, histopathological studies reveal subcortical bone necrosis. In 90% of the cases there is an ankle sprain in the past medical history although a direct correlation with trauma as exclusive trigger is not obvious. A possible approach is an osteochondral fracture in combination with an already existing osteonecrosis. A staged treatment regime is advised. In asymptomatic cases conservative treatment is advocated independent of the stage. Symptomatic patients with Hepple stages I, II and V and intact cartilage surface should undergo retrograde drilling in combination with a subchondral filling with cancelleous bone. If a cartilage defect is present (Hepple stages III, IV, V), an osteochondral transplantation is reasonable. Only if the defect zone is >2.5 cm2 should a debridement combined with a transplantation of cancellous bone and an ACT be considered. The sole anterograde drilling in our opinion should only be performed as an exception.

Suckel A; Hoyer M; Raab C; Wünschel M

2012-06-01

95

Treatment of large cystic medial osteochondral lesions of the talus with autologous osteoperiosteal cylinder grafts.  

UK PubMed Central (United Kingdom)

PURPOSE: To investigate the clinical, radiologic, and second-look arthroscopic outcomes of autologous iliac crest osteoperiosteal cylinder graft transplantation for medial osteochondral lesions of the talus (OLTs) with large subchondral cysts. METHODS: Between January 2008 and December 2010, 17 consecutive cases of medial OLT with a subchondral cyst larger than 10 mm in diameter received transplantation of autologous osteoperiosteal cylinder graft, which was harvested from the ipsilateral iliac crest. The visual analog scale score for pain during daily activities, American Orthopaedic Foot & Ankle Society hindfoot and ankle scores, and subjective satisfaction survey rating were obtained. Plain radiographs and magnetic resonance imaging of the ankle were obtained before and after surgery. In 13 cases second-look arthroscopy was performed 12 months postoperatively and the cartilage repair was assessed with the criteria of the International Cartilage Repair Society. RESULTS: Sixteen patients were available for follow-up at a mean of 32.6 months (range, 24 to 48 months). The mean visual analog scale score decreased from 5.51 ± 0.83 preoperatively to 0.98 ± 0.98 at the latest follow-up, and the median American Orthopaedic Foot & Ankle Society score improved from 75 preoperatively to 90 at the latest follow-up. Seven patients resumed sporting activities. Overall, 7 patients rated the result as excellent, 8 as good, and 1 as fair. The radiolucent area of the cysts disappeared on the plain radiographs in all cases. The mean Magnetic Resonance Observation of Cartilage Repair Tissue score was 60 ± 9.4 points, whereas subchondral bone edema persisted on the postoperative magnetic resonance images in 16 cases. The mean International Cartilage Repair Society arthroscopic score for cartilage repair at second-look arthroscopy was 9 ± 1.4 points. CONCLUSIONS: Autologous iliac crest osteoperiosteal cylinder graft transplantation with supplemental bone grafting is a simple, safe, and effective procedure for treatment of large cystic medial OLT. It can successfully fill the subchondral cyst and repair the cartilage defect. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Hu Y; Guo Q; Jiao C; Mei Y; Jiang D; Wang J; Zheng Z

2013-08-01

96

Slope protection method for planting  

UK PubMed Central (United Kingdom)

Soil including a setting agent such as fiber-soil-cement or the like is sprayed onto a slope so that corrugations extending substantially in parallel to the horizon are formed. Grooves and ridges of the corrugated surface provide conditions for allowing plants to grow on the protected slope.

KOBAYASHI TSUGUO

97

Reconstruction of osteochondral lesions of the talus with autologous spongiosa grafts and autologous matrix-induced chondrogenesis.  

UK PubMed Central (United Kingdom)

BACKGROUND: Osteochondral lesions (OCLs) of the talus are a common entity in sports orthopaedics. There are several operative techniques with a good outcome on follow-up examinations. However, limitations such as sacrificing healthy cartilage (osteochondral autograft transfer system [OATS], mosaicplasty), multiple-stage operative procedures (matrix-induced autologous chondrocyte transplantation [MACI], autologous chondrocyte implantation [ACI]), high costs (ACI, allograft), and limited availability (allograft) do remain and reflect potential drawbacks of the currently used techniques. PURPOSE: To describe a novel operative technique for the treatment of OCLs of the talus in the form of an economically efficient, 1-step procedure combining OCL debridement, spongiosaplasty, and sealing of the OCL area with a collagen matrix. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty-six patients underwent surgery receiving a modified autologous matrix-induced chondrogenesis (AMIC)-aided repair of OCLs of the talus consisting of debridement, autologous grafting, and sealing of the defect with a collagen scaffold. Ligament repair was performed in 17 of 26 cases. A corrective calcaneal osteotomy was performed in 16 of 26 cases. Clinical and radiological assessment was performed before and a minimum of 24 months after surgery (mean, 31 months; range, 24-54 months). Clinical examination included the American Orthopaedic Foot and Ankle Society (AOFAS) ankle score and the visual analog scale (VAS) for pain. Radiological imaging included single-photon emission computed tomography-computed tomography (SPECT-CT) and magnetic resonance imaging (MRI). The magnetic resonance observation of cartilage repair tissue (MOCART) score was applied, and sport activity was documented. RESULTS: The AOFAS ankle score improved significantly from a mean of 60 points preoperatively (range, 17-79 points) to 89 points (range, 61-100 points) postoperatively (P < .01). The preoperative pain score averaged 5 (range, 2-8), improving to an average of 1.6 (range, 0-7) postoperatively (P < .01). The MOCART score for cartilage repair tissue on postoperative MRI averaged 62 points (range, 20-95 points). Complete filling of the defect at the level of the surrounding cartilage was found in 35%, and complete filling with a hypertrophic cartilage layer was found in 50% of the patients. Normal signal intensity of the repair tissue compared with the adjacent native cartilage was seen in 15%, with nearly normal activity in 69%. Nineteen patients (73%) participated in sports before the onset of symptoms compared with 3 (12%) at the time of surgery. The number increased to 16 patients (62%) at postoperative follow-up. CONCLUSION: The modified AMIC procedure is safe for the treatment of OCLs in the ankle with overall good clinical and MRI results.

Valderrabano V; Miska M; Leumann A; Wiewiorski M

2013-03-01

98

Geomorphology of continental slope canyons  

Science.gov (United States)

Work on the US Atlantic slope reveals some remarkably analogous geomorphological properties to subaerial surfaces. Although the processes creating and modifying submarine slopes are different to those affecting landscapes above sea level, these geometrical similarities suggest that it may become possible to model slope evolution by analogous methods to those in subaerial geomorphology. Canyons in continental slopes, for example, can have similar "concavity" to bedrock eroding rivers (upwards-curved longitudinal profiles), tributaries can join main channels at confluences with smoothly converging elevations (obeying Playfair's Law), and tributaries with smaller contributing area tend to be steeper than their associated principal channels. Knickpoints in channels of tectonically active slopes also show fluvial-like tendencies, for example, there is evidence that they can advect up-stream or smooth out like in alluvial channels. Based on these observations, work has concentrated on assessing whether the "flow power" erosion models of fluvial geomorphology can be adapted to model submarine canyons. Other features of the Atlantic slope canyons can also be analogous to subaerial systems, for example, inter-canyon ridges can be sharp where bounded by steep, linear hillslopes analogous to threshold slopes on land. Many weakly incised areas of the uppermost continental slope in the USA Atlantic are smooth and upwards-convex between channels, much like in diffusive lowland landscapes. While some of this correspondence is fortuitous, the gravity effect on saltating sand may produce a down- slope movement proportional to local bed gradient that leads to a diffusive-like evolution of the surface topography in some circumstances.

Mitchell, N. C.

2006-12-01

99

Car Depreciation (rate and slope)  

Science.gov (United States)

The purpose of this activity is for students to use the concept of the rate of depreciation in a real world situation to investigate the relationship between rate and slope. Students create ordered pairs, graph depreciating car values, and calculate rates of depreciation, then identify that the rate of depreciation = slope of the line. Using the equation they then solve for future values and times.

2010-01-01

100

Concrete edge slope recovering structure  

UK PubMed Central (United Kingdom)

The utility model relates to a concrete slope surface vegetation restoring structure. The utility model solves the problem of providing a concrete slope surface vegetation restoring structure. The structure connects a rock soil mass in concrete surface layer with a stroma layer outside, exchanges nutritional components, makes up for a nutrient loss of the stroma layer, and keeps a growth effect of ecological layer on the slope surface, greatly reduceds a work of maintenance and management in late stage. A technical scheme to solve the problem is that the concrete slope surface vegetation restoring structure, a concrete spraying layer and a stroma layer are laid successively from inside to outside on the rock soil mass, the stroma layer is fixed by a iron wire netting via a post pin, the characterization is: a material guiding hole and a root guiding hole which are connected with the rock soil layer is arranged on the concrete spraying layer, a group of sustained-release nutrient rod is arranged between the iron wire netting and the concrete spraying layer, where is the external outlet of the material guiding hole. The utility model can be used in highway, railway slope, water conservancy and hydropower project slope, etc.

LI SHUYI ZHANG

 
 
 
 
101

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

Energy Technology Data Exchange (ETDEWEB)

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)

Anon.

2003-09-01

102

A systematic review on the reporting of outcome data in studies on autologous osteochondral transplantation for the treatment of osteochondral lesions of the talus.  

UK PubMed Central (United Kingdom)

PURPOSE: The purpose of this study was to systematically review studies on autologous osteochondral transplantation (AOT) for osteochondral lesions (OCLs) of the talus and descriptively analyze the outcome data reported to determine whether it is consistent from one study to another and able to be pooled for systematic review. METHODS: A systematic electronic search was performed using the MEDLINE and EMBASE databases. Studies that were published between January 1966 and June 2011 were included in the review. Only studies that reported data specifically on AOT for treatment of OCLs of the talus and written in English were included in this review. A predefined data sheet with 36 variables was created, and it was determined whether or not each of those variables were reported or not reported. The 36 variables were then grouped into 6 categories, and the categorical means were reported. RESULTS: A total of 20 studies were included in this systematic review. The categories of general demographics and study design were generally well reported (each more than 80% of studies). Patient-reported outcomes and clinical variables were reported less in 73% and 67% of studies, respectively. The least-reported categories were patient history (45%) and imaging data (49%). CONCLUSIONS: Inconsistencies and an underreporting of data were apparent between studies, such that pooling was deemed not possible. An effort must be made by investigators to ensure that there is adequate reporting of data in studies of AOT treatment for OCLs of the talus.

Hannon CP; Baksh N; Newman H; Murawski CD; Smyth NA; Kennedy JG

2013-06-01

103

Factors influencing result of autologous chondrocyte implantation in osteochondral lesion of the talus using second look arthroscopy.  

UK PubMed Central (United Kingdom)

This study is to know the factors that may affect cartilage repair after autologous chondrocyte implantation (ACI) for the treatment of an osteochondral lesion of the talus (OLT) as seen through a second look arthroscopy. A total of 38 patients who had ACI treatment for OLT underwent a second look arthroscopy 1 year after the ACI operation. A modified magnetic resonance observation of cartilage repair tissue (MOCART) scoring system was used to assess the outcome of the repaired cartilage. Influencing factors were sex, accompanied procedure, location, site, depth, pre-operative AOFAS score, size and age. Factors that may affect cartilage repair after ACI treatment for OLT were evaluated. Of the different factors assessed, sex (P=0.75), accompanied procedure (P=0.50), depth (P=0.08), location (P=0.54), site (P=0.50) and pre-operative AOFAS score (P=0.42) were found not to affect cartilage repair after ACI treatment for OLT. The size of the lesion (P=0.0021) and patient's age (P=0.01) were the influential factors. As a result, factors affecting repaired cartilage formation after ACI of OLT were found through the second look arthroscopy. It was determined that not all of the factors affecting the clinical outcome after ACI for the repair of an OLT affected cartilage repair after ACI.

Lee KT; Lee YK; Young KW; Park SY; Kim JS

2012-08-01

104

Bony periosteum-covered iliac crest plug transplantation for severe osteochondral lesions of the talus: a modified mosaicplasty procedure.  

UK PubMed Central (United Kingdom)

PURPOSE: This study reports first evidence of a modified procedure for osteochondral autologous transplantation where bony periosteum-covered plugs are harvested at the iliac crest and transplanted into the talar osteochondral lesion. METHODS: Thirteen out of 14 patients, average age 39.6 (SD 14.4) years, were followed clinically and radiographically for a median of 25 (24-28) months (minimal follow-up, 24 months). RESULTS: For these 13 patients, the American Orthopaedic Foot and Ankle Society hindfoot score increased from 47 (SD 11) points pre-operatively, to 81 (SD 14) points postoperatively (p < 0.0001). The average pain score decreased from 6.6 (SD 1.3) points pre-operatively, to 1.4 (SD 1.9) points postoperatively (p < 0.0001). Seven patients returned to sports activity. Radiographically good plug osteointegration was observed in nine out of 11 ankles. Follow-up arthroscopy showed fibrous cartilage in four ankles, periosteum hypertrophy in five ankles, and partial or total missing of coverage of the bone in three ankles. Three revision surgeries had to be performed. CONCLUSIONS: This modified mosaicplasty might be recommended for severe and recurrent osteochondral lesions of the talus and may lead to restoration of the subchondral bone stock, formation of fibro-cartilage, and stable joint function. LEVEL OF EVIDENCE: IV.

Leumann A; Valderrabano V; Wiewiorski M; Barg A; Hintermann B; Pagenstert G

2013-07-01

105

Three-Dimensional Matrix-Induced Autologous Chondrocytes Implantation for Osteochondral Lesions of the Talus: Midterm Results  

Science.gov (United States)

Introduction. We evaluate the midterm results of thirty patients who underwent autologous chondrocytes implantation for talus osteochondral lesions treatment. Materials and Methods. From 2002 to 2009, 30 ankles with a mean lesion size of 2,36?cm2 were treated. We evaluated patients using American Orthopaedic Foot and Ankle Surgery and Coughlin score, Van Dijk scale, recovering time, and Musculoskeletal Outcomes Data Evaluation and Management System. Results. The mean AOFAS score varied from 36.9 to 83.9 at follow-up. Average of Van Dijk scale was 141.1. Coughlin score was excellent/good in 24 patients. MOCART score varied from 6.3 to 3.8. Discussion. This matrix is easy to handle conformable to the lesion and apply by arthroscopy. No correlation between MRI imaging and clinical results is found. Conclusions. Our results, compared with those reported in literature with other surgical procedures, show no superiority evidence for our technique compared to the others regarding the size of the lesions.

Magnan, B.; Samaila, E.; Bondi, M.; Vecchini, E.; Micheloni, G. M.; Bartolozzi, P.

2012-01-01

106

Earthquake-induced slope displacements  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a finite-element analysis to evaluate earthquake-induced displacements in slopes. The procedure takes into account the nonlinear characteristics of the materials, spatial variation of strength (friction) along the potential failure surface and the inertial effects of the sliding wedge considered as a flexible multi-degree of freedom system. The potential effects are shown through hypothetical cases using two different seismic events. The model proposed in this paper is compared with other methods.

E. Botero J.; M. P. Romo

2003-01-01

107

A simple limit for slope instability  

CERN Document Server

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.

Stoppa, J

2009-01-01

108

Computing boundary slopes of 2-bridge links  

CERN Multimedia

We describe an algorithm for computing boundary slopes of 2-bridge links. As an example, we work out the slopes of the links obtained by 1/k surgery on one component of the Borromean rings. A table of all boundary slopes of all 2-bridge links with 10 or less crossings is also included.

Hoste, J; Hoste, Jim; Shanahan, Patrick D.

2005-01-01

109

Geotechnical system reliability of slopes  

International Nuclear Information System (INIS)

[en] 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

1995-01-01

110

Slope stability in surface mining  

CERN Multimedia

As we enter the 21st century, mines are being planned to reach depths of more than 1,100 meters, waste rock embankments have surpassed 600 meters in height, tailings dams have reached heights of 200 meters, and heap leach facilities have topped 150 meters. The push toward higher, deeper, and steeper, along with the larger and more productive equipment in use today, continues to test our tools and capabilities. Slope Stability in Surface Mining documents the progressive rise in technical understanding and sophistication in the field. Only by continuously collecting and exchanging information ca

Hustrulid, William A; Van Zyl, Dirk JA

2001-01-01

111

Slopes of overconvergent 2-adic modular forms  

CERN Multimedia

The slope of a p-adic overconvergent eigenform of weight k is the p-adic valuation of its U_p eigenvalue. We find the slope of all 2-adic finite slope overconvergent eigenforms of tame level 1 and weight 0. As a consequence we prove that any finite slope 2-adic overconvergent eigenform of tame level 1 and weight 0 has coefficients in Q_2. These results provide evidence towards conjectures of the first author that predict the slopes of classical p-adic modular forms under a mild ``Gamma_0(N)''-regular hypothesis on p.

Buzzard, K; Buzzard, Kevin; Calegari, Frank

2003-01-01

112

Vascularized periosteal graft from the first metatarsal bone: a new technique to prevent collapse of osteonecrosis of the talus in children. A case report.  

UK PubMed Central (United Kingdom)

Several microsurgical techniques have been described for the treatment of osteonecrosis of the talus (ONT). Recently reported in children, vascularized periosteal grafts showed promising revascularizing properties. We report a novel technique using a pedicled periosteal graft from the first metatarsal bone to treat steroid-induced early Ficat-Arlet stage III ONT in an 11-year-old boy. The patient presented initial favorable clinical and radiological results which were maintained at 34 months during the last follow-up. Through this original technique, and basing on the powerful osteogenic and vasculogenic propreties of periosteal flaps, we could effectively induce bone revascularization and prevent further collapse of the talar dome.

Soldado F; Barrera-Ochoa S; Fontecha CG; Haddad S; Barastegui D; Barber I; Rego P

2013-01-01

113

Fuzzy random reliability of slope`s two dimensional progressive failure  

Energy Technology Data Exchange (ETDEWEB)

According to the slope`s spatial variability theory, slope failure is regarded as a two-dimensional progressive process in which the failure spreads from its local area to the other ones gradually, being of random and fuzzy nature. A model of the fuzzy-random reliability of slope`s two-dimensional progressive failure has been put forward on the basis of the limit analysis. From the model, the calculation formula of the slope`s fuzzy-reliability is derived. 9 refs., 5 fig., 1 tab.

Zhou, Q. [China University of Mining and Technology, Beijing (China). Beijing Graduate School

1996-06-01

114

Slope filtrations for relative Frobenius  

CERN Multimedia

The slope filtration theorem gives a partial analogue of the eigenspace decomposition of a linear transformation, for a Frobenius-semilinear endomorphism of a finite free module over the Robba ring (the ring of germs of rigid analytic functions on an unspecified open annulus of outer radius 1) over a discretely valued field. In this paper, we give a third-generation proof of this theorem, which both introduces some new simplifications (particularly the use of faithfully flat descent, to recover the theorem from a classification theorem of Dieudonne-Manin type) and extends the result to allow an arbitrary action on coefficients (previously the action on coefficients had to itself be a lift of an absolute Frobenius). This extension is relevant to a study of (phi, Gamma)-modules associated to families of p-adic Galois representations, presently being initiated by Berger and Colmez.

Kedlaya, K S

2006-01-01

115

Immediate effect of a single anteroposterior talus mobilization on dorsiflexion range of motion in participants with orthopedic dysfunction of the ankle and foot.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The purpose of this study was to determine the immediate effects of a single anteroposterior mobilization of the talus on the active dorsiflexion range of motion (ROM) in participants with different orthopedic foot and ankle injuries. METHODS: This study included 30 male and female participants aged 18 to 50 years with unilateral orthopedic foot and ankle dysfunction. All participants underwent 3 sets of active dorsiflexion ROM measurement in both ankles. Measurements included baseline, post-first treatment, and post-second treatment values. Participants received either joint mobilization or manual contact (control) on the affected ankle. Active dorsiflexion ROM was assessed using a biplanar goniometer with participants in the prone position and 90° of knee flexion. RESULTS: Both groups (joint mobilization and manual contact) showed increased active dorsiflexion ROM. However, the mean difference of dorsiflexion measurements before and after mobilization was greater than before and after control treatment. CONCLUSION: A single session of articular mobilization of the talus did not significantly increase dorsiflexion ROM in participants with orthopedic dysfunctions of the ankle and foot compared with a manual contact procedure.

Teixeira LM; Pires T; Silva RD; de Resende MA

2013-07-01

116

Contribution of magnetic resonance imaging in the diagnosis of talus skip metastases of Ewing's sarcoma of the calcaneus in a child: a case report  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Introduction Ewing's sarcoma of the calcaneus is rare. About thirty cases with calcaneus involvement have been reported in the literature. Talus skip metastases have rarely been described in the available literature Case presentation We report a case of a 14-year-old Moroccan boy, who presented with Ewing's sarcoma of his right calcaneus, diagnosed by swelling of the calcaneus evolving over a year. Radiography, computed tomography and magnetic resonance imaging showed an important tumoral process of the calcaneus and talus skip metastases. The diagnosis was confirmed with histology after a biopsy. In spite of amputation and postoperative chemotherapy, our patient died six months later due to secondary respiratory distress after lung metastasis. Conclusion Imaging, especially magnetic resonance, is important in the diagnosis of Ewing sarcoma and skeletal skip metastases. Treatment of Ewing's sarcoma consists of chemotherapy, radiation therapy and surgical resection depending on the stage and extent of the disease. With the exception of lesions in the calcaneus, the prognosis for disease-free survival of Ewing's sarcoma of the foot is excellent.

Jalal Hicham; Belhadj Zoubida; Enneddam Hind; Madhar Mohammed; Fikry Tarik; Essadki Omar; Ousehal Ahmed

2011-01-01

117

Contribution of magnetic resonance imaging in the diagnosis of talus skip metastases of Ewing's sarcoma of the calcaneus in a child: a case report.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Ewing's sarcoma of the calcaneus is rare. About thirty cases with calcaneus involvement have been reported in the literature. Talus skip metastases have rarely been described in the available literature CASE PRESENTATION: We report a case of a 14-year-old Moroccan boy, who presented with Ewing's sarcoma of his right calcaneus, diagnosed by swelling of the calcaneus evolving over a year. Radiography, computed tomography and magnetic resonance imaging showed an important tumoral process of the calcaneus and talus skip metastases. The diagnosis was confirmed with histology after a biopsy. In spite of amputation and postoperative chemotherapy, our patient died six months later due to secondary respiratory distress after lung metastasis. CONCLUSION: Imaging, especially magnetic resonance, is important in the diagnosis of Ewing sarcoma and skeletal skip metastases. Treatment of Ewing's sarcoma consists of chemotherapy, radiation therapy and surgical resection depending on the stage and extent of the disease. With the exception of lesions in the calcaneus, the prognosis for disease-free survival of Ewing's sarcoma of the foot is excellent.

Jalal H; Belhadj Z; Enneddam H; Madhar M; Fikry T; Essadki O; Ousehal A

2011-01-01

118

Analysis of Slope Stability Using Limit Equilibrium  

Directory of Open Access Journals (Sweden)

Full Text Available 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 property when it is developed under different types of geometry.

Abdoullah Namdar

2010-01-01

119

Effects of side slope on wheelchair performance.  

UK PubMed Central (United Kingdom)

Compensation for the downhill turning moment of a wheelchair on a 2-degree side slope results in retarding force approximately equal to the rolling drag of a wheelchair on a level surface. The total drag force on the wheelchair while transversing a sloping surface is, therefore, roughly double the rolling drag. In contrast, the net energy cost of propulsion on this side slope is only 30 percent greater than for a level surface. Side slope propulsion is managed by "dragging" the uphill rim while pushing the downhill rim. Although this results in increased mechanical efficiency through greater use of a smaller muscle mass, it is more difficult and tiring for the wheelchair user.

Brubaker CE; McLaurin CA; McClay IS

1986-04-01

120

A one-dimensional slope detection approach.  

UK PubMed Central (United Kingdom)

This paper extends the scale-invariant edge detector to the one-dimensional slope. It can accurately detect the slope and estimate its parameters. The method has been verified with several mathematical functions, sample sizes, and noise levels. A contrast-invariant operator is proposed to suppress noise. The inter-sample localization and interpolation greatly improve the accuracy. The proposed slope detector is also suitable for real-world signals. In additional to above-mentioned, a threshold formula is developed for the first derivative slope detector, and the upper-bound of the filterable noise level is also explored.

Zhang X; Liu C

2013-01-01

 
 
 
 
121

Novel ecological slope protection substrate building method  

UK PubMed Central (United Kingdom)

Disclosed is a novel method for constructing an ecological slope protection substrate, which pertains to the field of slope protection engineering, ecological restoration engineering and greening engineering. The construction process of the method of the invention is: first, leveling the slope surface needing restoring, excavating mouth-shaped pits on the slope surface, filling the mouth-shaped pits with multi-functional soil and finishing the construction of the slope protection substrate. The method for constructing the ecological slope protection substrate provided by the invention, by arranging the mouth-shaped pits on the slope surface, not only can change the status of soil impoverishment and the growth environment of vegetations, and provide essential fertilizers and nutrient substances for the sustainable growth of plants, but also can greatly increase the cohesive force between the guest soil layer and the fraction excavated, and increase the integral stability of the guest soil layer so as to effectively prevent the slope surface from integral damage by the continuous effect of rain. The method of the invention changes the mechanical characteristics and construction modes of the substrate and improves the present statuses of the poor stability and soil impoverishment of the substrate in the ecological slope protection.

WENNIAN XU; DEDAO PEI; HAIBO NIU; MINGTAO ZHOU; ZHENYAO XIA; CHAO SUN; PING GUO; SHUSONG ZHANG

122

Dental trauma on ski slopes.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Skiing and snow-boarding are winter sports with risk of dental trauma. The aim of the present study was to investigate the use of protective gear and the occurrence of dental trauma in amateur winter sports on ski slopes. MATERIALS AND METHODS: A total of 500 skiers and snowboarders (345 skiers, 110 snow-boarders, and 45 who rode both) were interviewed using a standardized questionnaire during one winter season (from January to April 2008). Sustained injuries and use of protective gear (including mouthguards) were assessed. RESULTS: Of the 500 interviewed, eleven (9 m, 2 f; 2.2%) had sustained dental trauma while skiing or snowboarding. Frequent riders were most susceptible to dental trauma (p < 0.001). 165 (33%) have sustained a skiing or snow- boarding accident at least once, males more often than females (p = 0.031). Protective gear was used by 337 (67.4%), helmet, back and wrist protectors being worn most often. Snow-boarders were generally protected best (p < 0.001). All riders who had sustained an accident (n = 124; 75.1%) wore protective gear at the time of the interview (p = 0.009). Only two of eleven who had sustained dental trauma wear a mouthguard now for winter sports. CONCLUSION: The results show that skiing and snowboarding pose only a small risk for dental trauma.

Innerhofer K; Krastl G; Kühl S; Baumgartner EN; Filippi A

2013-01-01

123

Litter decomposition and nitrogen release in a sloping Mediterranean subtropical agroecosystem on the coast of Granada (SE, Spain): Effects of floristic and topographic alteration on the slope  

UK PubMed Central (United Kingdom)

On the coast of Granada (SE, Spain), an economically important area for subtropical fruit cultivation, the crops are grown on orchard terraces. Also, high amounts of fertilizers, often excessive, are used in this type of intensive agriculture. However, each year significant fractions of nutrients taken up by the trees return to the soil by fallen leaves. Using a litter-bag technique, we assessed the decomposition rates and N-release in various types of litter. Our main purpose was to compare two different agroecosystem scenarios: (1) an unaltered slope consisting mainly of a mixture of herbaceous plants (Papaver rhoeas, Convolvulus sp., Malva sylvestris, Reseda phyteuma, Anacyclus sp., Sinapis arvensis, Medicago sp.) among spontaneous perennial woody shrubs (Genista umbellata, Olea europaea, Lavandula officinalis, Phlomis purpurea, Retama sphaerocarpa), and (2) an altered slope cultivated with subtropical trees on terraces: loquat (Eriobotrya japonica), mango (Mangifera indica), avocado (Persea americana), and cherimoya (Annona cherimola), with groundcover plantings of aromatic, medicinal, and melliferous plants (AMMPs) on the taluses of the terraces, which are usually used for erosion control: Lavandula dentata, Thymus mastichina, Satureja obovata, Rosmarinus officinalis, Anthyllis cytisoides. In the leaves from the subtropical crops, we found the highest decomposition rates in cherimoya and the lowest in mango (1.30 and 0.64years?¹, respectively). Leaves from mango and loquat registered initial peaks of N immobilization and later N-release, which was highest in cherimoya and avocado leaves (71.2 and 56.8% of the initial remaining N). In the spontaneous woody shrubs, O. europaea and G. umbellata were the slowest in decomposing (1.18 and 1.01years?¹, respectively) contrary to L. officinalis, which decomposed fastest (2.22years?¹). Only L. officinalis and P. purpurea registered a net N-release at the end of the study. The AMMPs showed different decomposition patterns: L. dentata registered the highest decomposition rates and Rosmarinus the lowest (1.9 and 1.1years?¹, respectively). T. mastichina, L. dentata, and S. obovata had the highest N-release, whereas R. officinalis and A. cytisoides showed N immobilization (183 and 122% of the initial N). Knowledge of the dynamics of nutrient release and litter decomposition will be useful for predicting nutrient availability and nutrient cycles in these types of agroecosystems where subtropical orchards are grown on terraces.

Rodríguez Pleguezuelo CR; Durán Zuazo VH; Muriel Fernández JL; Martín Peinado FJ; Franco Tarifa D

2009-11-01

124

Effects of Water on Slope Stability.  

Science.gov (United States)

A brief state-of-the-art review of the effects of water on slope stability and the techniques for analysis is presented. The effective stress principle and basic considerations of slope stability, including design factors of safety, are discussed briefly....

T. C. Hopkins D. L. Allen R. C. Deen

1975-01-01

125

Slope Stability. CEGS Programs Publication Number 15.  

Science.gov (United States)

|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…

Pestrong, Raymond

126

Rock slopes and reservoirs - lessons learned  

International Nuclear Information System (INIS)

[en] 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

1999-05-28

127

Rock slopes and reservoirs - lessons learned  

Energy Technology Data Exchange (ETDEWEB)

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.

Moore, D.P. [BC Hydro, Burnaby, BC (Canada)

1999-07-01

128

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

Science.gov (United States)

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.

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

2013-04-01

129

Eastern slopes grizzly bear project  

Energy Technology Data Exchange (ETDEWEB)

The cumulative effects of human activities on the grizzly bears in the central Canadian Rockies are not well known. As a result, a project was initiated in 1994 to address the urgent requirement for accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of this study will be used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers are monitoring 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers involved in the project are working with representatives from Husky Oil and Talisman Energy on the sound development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over seven years indicated that the grizzly bears have few and infrequent offspring. Using the information gathered so far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears recover very slowly from high mortality, and also considering that the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The status of the population and habitat of the grizzly bear will be assessed upon the conclusion of the field research phase in 2001. Models will be updated using the data obtained during eight years and will assist in the understanding of complex variables that affect grizzly bears.

NONE

2001-01-01

130

Green Alder Pattern in Relation to Slope-Area Scaling Regimes of a Headwater Basin in the Eastern Italian Alps  

Science.gov (United States)

The landscape of headwater alpine basins is strongly influenced by erosion processes. The scaling relationship between the local slope of a given point on the landscape and its drainage area reveals information about the dominant erosion process over geomorphic time scales. There has been significant research literature which documents how vegetation distribution is coupled with local topography. Understanding the interrelationship between the vegetation, especially between some plant species than others with local topography will help us to better understand how the landscape change due to a specific geomorphic process is related to vegetation change. In this paper a steep Alpine debris flow-landslide dominated headwater catchment with uniform lithology substrata, and vegetation characterized by various grass, shrub, and forest species has been considered. The basin was chosen as study area because it is representative of the lithological and physiographical conditions frequently observed in the Carnia region (Eastern Italian Alps). The work has focused on the analysis of scaling regimes of local slope versus contributing area in relation to each vegetation types with particular attention to the spatial distribution of Alnus viridis, the main shrub species present in the area. Alnus viridis, also known as Green Alder, is an early successional shrub growing up to 4 m that invades screes, landslide scree, avalanche debris on talus slopes, avalanche slide paths and pastures in the subalpine zone of the Alps. It is widespread on moist, north-exposed medium-steep slopes on silicious bedrock at an altitude ranging from 1500 to 2000 m a.s.l.. LiDAR-derived DSM (Digital Surface Model) served as the basis to evaluate the distribution of vegetation canopies. The LiDAR bare-ground elevation points were used for the DTM (Digital Terrain Model) interpolation at the same resolution of the DSM. The results revealed that there is significant relationship between the local slope and drainage area depicting the natural location of Green Alder and other vegetation types. Profound landslide/debris flow topographic signature is detected in areas where Green Alder prevails. Its pioneering ability to colonize the landslide scars and headwater channel hollows, makes it as a key species in the analysis of geomorphic processes at the hillslope/valley transition. The work has broad implications in geomorphology, landscape ecology, landscape evolution with vegetation dynamics for studies in high-altitude extreme-climate Alpine regions.

Tarolli, P.

2007-12-01

131

Establishing proof of concept: Platelet-rich plasma and bone marrow aspirate concentrate may improve cartilage repair following surgical treatment for osteochondral lesions of the talus  

Directory of Open Access Journals (Sweden)

Full Text Available Osteochondral lesions of the talus are common injuries in the athletic patient. They present a challenging clinical problem as cartilage has a poor potential for healing. Current surgical treatments consist of reparative (microfracture) or replacement (autologous osteochondral graft) strategies and demonstrate good clinical outcomes at the short and medium term follow-up. Radiological findings and second-look arthroscopy however, indicate possible poor cartilage repair with evidence of fibrous infill and fissuring of the regenerative tissue following microfracture. Longer-term follow-up echoes these findings as it demonstrates a decline in clinical outcome. The nature of the cartilage repair that occurs for an osteochondral graft to become integrated with the native surround tissue is also of concern. Studies have shown evidence of poor cartilage integration, with chondrocyte death at the periphery of the graft, possibly causing cyst formation due to synovial fluid ingress. Biological adjuncts, in the form of platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC), have been investigated with regard to their potential in improving cartilage repair in both in vitro and in vitro settings. The in vitro literature indicates that these biological adjuncts may increase chondrocyte proliferation as well as synthetic capability, while limiting the catabolic effects of an inflammatory joint environment. These findings have been extrapolated to in vitro animal models, with results showing that both PRP and BMAC improve cartilage repair. The basic science literature therefore establishes the proof of concept that biological adjuncts may improve cartilage repair when used in conjunction with reparative and replacement treatment strategies for osteochondral lesions of the talus.

Niall A Smyth; Christopher D Murawski; Amgad M Haleem; Charles P Hannon; Ian Savage-Elliott; John G Kennedy

2012-01-01

132

Comparison of observed and predicted slope winds  

Energy Technology Data Exchange (ETDEWEB)

Nocturnal drainage winds begin when air adjacent to an inclined surface flows down the slop because it is cooled more than the free air at some distance horizontally from the surface. These slope winds merge and are channeled by the topography to form the larger-scale drainage or mountain winds. This paper discusses the slope flow phase of the drainage wind. The predictions of a simple model for flow down a two-dimensional slope are compared to observations of the drainage wind obtained during the July 1979 ASCOT field study near Middletown, CA.

Horst, T.W.; Doran, J.C.

1980-07-01

133

Downhill slopes look shallower from the edge.  

UK PubMed Central (United Kingdom)

A dramatic failure of orientation constancy is documented in the perception of downhill slopes. Contrary to naïve expectation, steep downhill slopes look shallower from the edge than they do from back from the edge. Three experiments document and quantify this failure of constancy for real and virtual surfaces using a variety of dependent measures. Two additional studies document overestimation of both non-visually perceived head pitch and perceived gaze declination. A model of orientation constancy failure is fit to the data that combine exaggerations in perceived gaze declination with exaggerated scaling of perceived optical slant. These findings support a functional scale-expansion model of error in slope perception.

Li Z; Durgin FH

2009-01-01

134

Effects of side slope on wheelchair performance.  

Science.gov (United States)

Compensation for the downhill turning moment of a wheelchair on a 2-degree side slope results in retarding force approximately equal to the rolling drag of a wheelchair on a level surface. The total drag force on the wheelchair while transversing a sloping surface is, therefore, roughly double the rolling drag. In contrast, the net energy cost of propulsion on this side slope is only 30 percent greater than for a level surface. Side slope propulsion is managed by "dragging" the uphill rim while pushing the downhill rim. Although this results in increased mechanical efficiency through greater use of a smaller muscle mass, it is more difficult and tiring for the wheelchair user. PMID:3723426

Brubaker, C E; McLaurin, C A; McClay, I S

1986-04-01

135

3D geodetic monitoring slope deformations  

Directory of Open Access Journals (Sweden)

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.

Sütti Juraj; Weiss Gabriel

1996-01-01

136

Method for greening vegetation module slope  

UK PubMed Central (United Kingdom)

The invention relates to a method for side slope virescence using vegetation. Antiseptic timber frames are made by an antiseptic board a soil engineering cloth bag with corresponding size with the square antiseptic timber frame is made and is filled with planting substrate the antiseptic timber frames are clenched on a side slope needing vegetation virescence in sequence by pre-fixing roof bolts the soil engineering cloth bag filled with the planting substrate is arranged in the antiseptic timber frames lianes are planted on the soil engineering cloth bag and the growth of the lianes actualizes the side slope virescence. The invention can be applied to slope surfaces with any gradient, the material sources is wide and cheap so as to reduce the pressure of economic cost the operation is easy, the construction is simple, and large-area generation is available large-scale green coating can be realized within one to two years. The invention enlarges the survival platform of the plants to slop surfaces, and the mural type planting mode gives full play to the characteristic of the lianas and because the species of the lianas is abundant, various combinations of plants at the slope surface can build an abundant side-slope landscape effect within a short period.

HONGTAO LIU; KAIJI XIE

137

Electrocardiogram derived respiration from QRS slopes.  

UK PubMed Central (United Kingdom)

A method for estimation of respiratory rate from electrocardiogram (ECG) signals, based on variations in slopes of QRS complexes, is presented. 12 standard leads, 3 leads from vectorcardiogram (VCG), and 2 additional non-standard leads derived from VCG loops were analysed. A total of 34 slope series were studied, 2 for each analysed lead: slopes between the peak of Q and R waves, and between the peak of R and S waves. Information of QRS slopes series was combined in order to increase the robustness of estimation. Evaluation is performed over a database containing ECG and respiratory signals simultaneously recorded in 17 subjects spontaneously breathing during a tilt table test. Respiratory rate estimation is performed with information of 4 different combinations of QRS slope series. The best results in respiratory rate estimation error terms are 0.72±4.34%(0.46±7.59 mHz). These results outperform those obtained with other known methods, motivating the use of QRS slopes to obtain reliable respiratory rate estimates.

Lazaro J; Alcaine A; Gil E; Laguna P; Bailon R

2013-07-01

138

Gravity currents shoaling on a slope  

Science.gov (United States)

Laboratory experiments are performed to examine gravity currents propagating into an ambient of uniformly decreasing depth. Predominantly, the study is of a surface gravity current shoaling over a bottom slope as it approaches a corner between the horizontal surface and the sloping topography. For sufficiently high Reynolds number currents, they are found to propagate at a constant speed over the slope until the depth of the ambient below the nose is comparable to the depth of the current in the lee of the gravity current nose. It then decelerates at a constant rate set by the product of the reduced gravity, g', and the magnitude of the topographic slope, s. The shape of the head evolves to form a front parallel to the slope itself and the ambient ahead of the current accelerates downslope with significant turbulence between the ambient and current head. The dependency of the deceleration upon g's is anticipated from WKB-like extensions of steady-state gravity current theory that include the effect of the ambient depth in one case varying slowly in space as the current first passes over the slope and in another case varying slowly in time as the nose approaches the corner. However, the measured deceleration magnitude of ~= 0.31( +/- 0.01)g's is found to be larger than these heuristic predictions.

Sutherland, Bruce R.; Polet, Delyle; Campbell, Margaret

2013-08-01

139

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

Science.gov (United States)

...2010-07-01 false Wall, bank, and slope stability. 56.3130 Section 56...56.3130 Wall, bank, and slope stability. Mining methods shall be...will maintain wall, bank, and slope stability in places where persons work...

2010-07-01

140

Putting beach slope prediction into perspective  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The storage capacity of any given tailings storage facility (TSF) is a function of the volume available for the tailings, for which the geometry of the final upper surface of the tailings is most important. One of the advantages that can be obtained from thickening tailings prior to discharge is that the tailings can be stacked at a steeper beach angle than is obtainable with conventional low-density slurries. However, there is at present no universally accepted method av (more) ailable for the accurate prediction of tailings beach slopes. This paper examines the current situation with the objective of putting the quest for a method for the accurate prediction of beach slopes into perspective. The paper references published reviews of the best-known beach slope prediction methods. However, there do not appear to be any independently verified projects or published references to projects on which a Class A prediction has been validated for any of these approaches, and in those instances where projects have been implemented correlation of actual with predicted slopes has been poor - often due to differences between the properties of the tailings assumed in the design and those actually achieved in the field. The author also concludes that flume-scale testing cannot be taken as a reliable indicator of full-scale performance, and suggests that the outcome of any current predictive method should be used by experienced practitioners as only one of a range of indicators in order to suggest a range of slope angles likely to result for any given operation. Practice has shown that it is possible to manipulate beach slopes by changes to the disposal technique, such as limiting the rate of discharge per discharge point and by increasing or decreasing yield stress, but the impact of these changes cannot readily be predicted. There are also newly emerging technologies, such as the injection of a polymer into the tailings at discharge, that will enhance the dewatering of tailings and hence expedite the consolidation of the tailings, that could well facilitate the development of steeper beach slopes. The overall conclusion is that with the current state of knowledge, the accurate prediction of beach slopes is not possible. Furthermore, in view of the inherent variability of the tailings parameters from any operation, it may well be of more value to concentrate on developing an understanding of the means by which the tailings parameters may be manipulated by the operators to achieve a given beach slope than to concentrate wholly on developing a generic beach slope prediction model.

Jewell, R.J.

2012-01-01

 
 
 
 
141

Valley Evolution and Controls on Present-Day Rock Slope Processes in the Matter and Saas Valleys, Switzerland  

Science.gov (United States)

Landforms in the Matter and Saas Valleys (Kanton Valais, Switzerland) indicate a progressive upstream transition from fluvially dominated to glacially dominated terrains. Large glaciers currently reside in the headwaters of both valleys, and the region was a major ice contributor to the Rhone Valley during the LGM. Characteristic geomorphic indicators linked to morphology, extent of glacial sediments and ice-rock contact surfaces, as well as river and terrace profiles within the two valleys suggest a parallel temporal evolution, despite variations in catchment size, lithology, and glacial input. Slope morphology and fan deposits indicate a concentration of high-energy rock slope activity (such as rock falls, topples, and slides) within a transitional geomorphic domain in the lower 1/3 of both valleys. This transitional domain is defined by a characteristic moderate gradient, linear, river profile. It separates a downstream detachment-limited fluvial domain from a transport-limited domain upstream, where a broad alluvial plain forms a thick infill in the relict glacial valley. Hillslope erosional processes appear considerably less developed and active in these neighboring domains. While the rock slope activity in the transitional domain initially seems to be a clear process response to renewed Holocene fluvial incision in the lower section of the valleys, mapping of glacial landforms indicates only limited incision may have taken place. Activity is concentrated on steep valley walls which extend up to 700m above the current valley floor. These are buttressed by significant talus deposits, which combined with the topography, mean there is likely to be little direct connection from the post-glacial fluvial activity to the erosional hillslope processes. Initial investigations suggest that a combination of repeated glacial erosion and debuttressing, as well as fluvial processes during interglacials may have lead to a significant, consistent differences in post-glacial stress redistribution in each domain. Large deviatoric stresses associated with high relief, and the removal of sedimentary buttresses in the transitional domain, may have induced fracturing of the rock mass through exfoliation and static fatigue, and conditioned rock slopes for ongoing failure.

Leith, K.; Kos, A.; Löw, S.; Moore, J.

2009-04-01

142

Prótese do tornozelo híbrida em um caso de necrose avascular pós-traumática do tálus Hybrid ankle prosthesis in a case of post-traumatic avascular necrosis of the talus  

Directory of Open Access Journals (Sweden)

Full Text Available As fraturas do astrágalo originam frequentemente artrose pós-traumática tardia. Nestes casos, a utilização de próteses do tornozelo não cimentadas de última geração tem sido evitada pela presença de necrose avascular. Relatamos o caso de um paciente com 65 anos que se apresenta quatro anos após uma fratura do colo do astrágalo. Apresentava uma artrose do tornozelo dolorosa (escala AOFAS do retropé e tornozelo 19) e necrose avascular com colapso de toda a cúpula astragalina. Dada a extensão da necrose, foi decidido cimentar o componente protésico astragalino. Um ano após a cirurgia, o paciente apresenta bom resultado clínico e radiológico (escala AOFAS do retropé e tornozelo 87) e está satisfeito com o procedimento. Não temos conhecimento de nenhum relato semelhante na literatura.Talus fractures often lead to late post-traumatic arthrosis. In such cases, the use of latest generation, cementless prostheses has been hindered by the presence of avascular necrosis. We report the case of a 65-year-old patient who presented four years after a talus neck fracture. He had painful ankle arthrosis (AOFAS ankle-hindfoot score 19) and avascular necrosis, with collapse of the entire talar dome. Given the extent of the necrosis, it was decided to cement the talus prosthetic component. One year after the surgery, the patient shows good clinical and radiological results (AOFAS ankle-hindfoot score 87) and is satisfied with the procedure. We are not aware of any similar reports in the literature.

Ricardo Jorge Gomes de Sousa; Ricardo Pedro Ferreira Rodrigues Pinto; Marta Maria Teixeira de Oliveira Massada; Manuel Alexandre Negrais Pinho Gonçalves Pereira; José Muras Geada; Isabel Maria Gonçalves Costa

2011-01-01

143

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

International Nuclear Information System (INIS)

[en] 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)

2008-01-01

144

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 sta...

Leynaud Didier; Sultan Nabil

145

Submarine slope failure offshore Uruguay - First Results  

Science.gov (United States)

New geophysical acquired during cruise M78 with RV "Meteor" in 2009 reveal a large-scale slope failure complex. Positioned between 1800 and 3300 m water depth, the slope failure affected an area of at least 1200 km². The failure is hosted in contouritic deposits. The morphology of the up 70 m high headwalls is underlain by a deeper reflector which we interpret as detachment. Listric faults positioned upslope these headwalls root in this detachment and are precursor of future failure at this location. The detachment correlates with a regional BSR mapped by Uruguayan colleagues. Cores recovered from 3 transects across the failure complex confirm that the acoustic transparent units are debrites. Sedimentological evidence in accordance with hydro-acoustic data indicate that debrites deposited downslope this failure complex are recent features on the slope.

Winkelmann, Daniel; Langenbacher, Julia; Anasetti, Andrea; Strasser, Michael; Preu, Benedict; Schwenck, Tilmann; Krastel, Sebastian

2010-05-01

146

Seasonal flows on warm Martian slopes.  

UK PubMed Central (United Kingdom)

Water probably flowed across ancient Mars, but whether it ever exists as a liquid on the surface today remains debatable. Recurring slope lineae (RSL) are narrow (0.5 to 5 meters), relatively dark markings on steep (25° to 40°) slopes; repeat images from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment show them to appear and incrementally grow during warm seasons and fade in cold seasons. They extend downslope from bedrock outcrops, often associated with small channels, and hundreds of them form in some rare locations. RSL appear and lengthen in the late southern spring and summer from 48°S to 32°S latitudes favoring equator-facing slopes, which are times and places with peak surface temperatures from ~250 to 300 kelvin. Liquid brines near the surface might explain this activity, but the exact mechanism and source of water are not understood.

McEwen AS; Ojha L; Dundas CM; Mattson SS; Byrne S; Wray JJ; Cull SC; Murchie SL; Thomas N; Gulick VC

2011-08-01

147

Blasting and excavating on precarious rock slopes  

Energy Technology Data Exchange (ETDEWEB)

There is an intuitive tendency to equate rock strength with rock stability, yet the two must be evaluated separately. A slope in strong hard rock is not necessarily stable, nor is a slope in weathered weak rock necessarily unstable. In some cases the reverse is true, depending on the geometry of joints and weak planes. The time element is a matter of special concern, that is how suddenly the failure begins and how rapidly it progresses. An important element in avoiding catastrophes is to study the site geology for dangerous conditions, implement the types of blasting procedures that minimize failures, and evaluate the potential use of reinforcement or other mechanical stabilizing procedures. It may be possible to reinforce the perimeters of structural excavations, but that is not usually possible for quarry or surface mine operations. However, it is often possible to change a dangerous operation into a safe one merely by changing the orientation, sequence or dimensions of the work without changing other details of the blasting designs. Several important principles are illustrated in this paper, using case histories. One case is that of a catastrophic slope failure in Mexico, and the remedial procedures used to get the work back into operation. That case is compared to large-scale work which was done safely on a similar site in Spain, even with an 850 ft high slope and up to 200 ft between safety benches. Also illustrated are some of the procedures used for delicate work on sensitive slopes at a site in Colombia, South America, and those used to preserve a delicate narrow rib of rock in a deep river canyon on the Snake River in Idaho. Brief reference is made also to slope damage on a Canadian project.

Oriard, L.L. [Lewis L. Oriard, Inc., Huntington Beach, CA (United States)

1996-12-01

148

Evaluation of Slope Stability Performance in Different Methods  

Directory of Open Access Journals (Sweden)

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.

Abdoullah Namdar,; Azam Khodashenas Pelko

2010-01-01

149

Analysis of slope stability of earth structure regarding their interference / ?????? ???????????? ??????? ????????? ?????????? ? ?????? ?? ????????? ???????  

Directory of Open Access Journals (Sweden)

Full Text Available Analysis of slope stability of earth structures in most cases is carried out irrelatively of the function fulfilled by the slope in the given structure. The article shows that the ignorance of slope interference within the structure can lead to serious accuracies in evaluation of the degree of their stability. Authors consider recommendation in size of some geometric parameters of slopes. With their help analysis of slope stability can be carried out without taking into account their interference. / ????????, ??? ????????????? ????????? ??????? ??????? ? ??????? ?????????? ????? ????????? ? ????????? ???????????? ? ??????????? ??????? ?? ????????????. ????????? ???????????? ?? ???????? ????????? ?????????????? ?????????? ???????, ??? ??????? ?????? ?? ???????????? ????? ??????????? ??? ????? ????????? ???????.

Bogomolova ?.?. / ?????????? ?????? ?????????????; Kachurin Ya.V. / ??????? ???? ????????????; Kuzhel V.N. / ?????? ???????? ??????????; Yakimenko I.V. / ???????? ????? ????????????

2010-01-01

150

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.)

1999-01-01

151

Reorienting with terrain slope and landmarks.  

UK PubMed Central (United Kingdom)

Orientation (or reorientation) is the first step in navigation, because establishing a spatial frame of reference is essential for a sense of location and heading direction. Recent research on nonhuman animals has revealed that the vertical component of an environment provides an important source of spatial information, in both terrestrial and aquatic settings. Nonetheless, humans show large individual and sex differences in the ability to use terrain slope for reorientation. To understand why some participants--mainly women--exhibit a difficulty with slope, we tested reorientation in a richer environment than had been used previously, including both a tilted floor and a set of distinct objects that could be used as landmarks. This environment allowed for the use of two different strategies for solving the task, one based on directional cues (slope gradient) and one based on positional cues (landmarks). Overall, rather than using both cues, participants tended to focus on just one. Although men and women did not differ significantly in their encoding of or reliance on the two strategies, men showed greater confidence in solving the reorientation task. These facts suggest that one possible cause of the female difficulty with slope might be a generally lower spatial confidence during reorientation.

Nardi D; Newcombe NS; Shipley TF

2013-02-01

152

Method for greening infertile side slope fields  

UK PubMed Central (United Kingdom)

The invention introduces a method for greening areas with barren side slopes. The method comprises the following steps: (1) by studying greening suitable planting conditions of a slope body(8), a greening plan is worked out (2) the slope body(8) is cleaned and dressed (3) ecological anti-sliding tenons (5) or systematic ecological anchor rods (3) or bar screens (10) and systematic ecological anchor rods (3) are arranged (4) porous degradable ecological bags (1) are evenly arranged, and link buckles(2) of ecological bags and porous degradable plastic blind pipes (4) are arranged between the porous degradable ecological bags(1) and (5) grass and bushes (6) are planted. The method has the advantages that: 1. the method can effectively resolve the problem of restoring ecological environment in the areas with the barren side slopes and make an individualized ecological design 2. the method can avoid water loss and soil erosion 3. the method can greatly prolong ecological duration and 4. the method is simple in construction, low in cost and wide in application range.

YANGUANG LI

153

Soil strength of slide slopes - inverse calculations  

Energy Technology Data Exchange (ETDEWEB)

Problems are discussed associated with control of slope stability in brown coal surface mines. Mean parameters of mechanical properties of soil and rocks determined on the basis of laboratory tests in many cases were inaccurate. Three schemes for determining soil mechanical properties based on so-called inverse analysis of one of the methods for slope stability control were used. Parameters which described the circular-cylindrical shape of slide surface of 59 cases of slope failures in the Turow brown coal surface mine in Poland are given in tables. The results of inverse analysis are also given. Inverse analysis was carried out using 3 methods. Parameters which characterize mechanical soil properties (mean parameters and calculated parameters) are determined on this basis. The indices which described the mean shear resistance calculated by means of 3 methods were compared. It was found that the differences among the indices ranged from 3 to 10%. The parameters calculated by means of the inverse analysis were 30 to 50% lower than those determined by means of conventional laboratory tests. Advantages of inverse analysis for control of slope stability in coal surface mining are discussed. 20 references.

Mazurek, J.

1986-01-01

154

On the slope of bielliptic fibrations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 s...

Barja Yáñez, Miguel Ángel

155

On Slip Surface and Slope Stability Analysis.  

Science.gov (United States)

The method of variational calculus is applied to obtain the shape of slip surface and the corresponding normal stress distribution. For a horizontal slope of uniform soil, a logarithmic spiral surface of angle Phi is found to be the most critical surface....

N. Snitbhan W. F. Chen

1973-01-01

156

Explicit limit equilibrium solution for slope stability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Conventional methods of slices used for slope stability analysis satisfying all equilibrium conditions involves generally solving two highly non-linear equations with respect to two unknowns, i.e. the factor of safety and the associated scaling parameter. To solve these two equations, complicated nu...

Zhu, DY; Lee, CF

157

Slope stability under rapid drawdown conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

158

Slope Stability, Triggering Events, Mass Wasting Events  

Science.gov (United States)

This article, authored by Professor Stephen A. Nelson of Tulane University, focuses on many aspects of slope stability. Some of these factors include: the role of water, troublesome earth materials, triggering events, and assessing and mitigating mass-wasting hazards. The article is filled with detailed diagrams along with accompanying textual descriptions that make a cohesive piece easily understood by many audiences.

Nelson, Stephen A.

2008-09-22

159

Error Reduction in Slope Stability Assessment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 conduc...

Fleurisson, Jean-Alain; Cojean, Roger

160

Gas hydrate influence on deepwater slope stability  

Energy Technology Data Exchange (ETDEWEB)

Solid ice-gas compounds called gas hydrates occur in deep ocean sediments around the world. It is known that when they melt, the solid ice converts to gas and water. If this happens in slope sediments, landslides might result. A study of relationships between slope stability and gas hydrates shows that there are many ways in which changes in the geologic environment may cause gas hydrates to melt. One example is sea level lowering of the magnitude experienced during the Pleistocene; the pressure decrease reduces the stability of the hydrate. Another is warming of hydrates by increased geothermal heat flow associated with the growth of salt diapirs beneath the region. Geologic changes such as these were modeled using classical 1-D heat flow theory. Typical values for sediment and hydrate properties were used in a variety of potential geologic and environmental conditions that characterize some continental slope regions. Emphasis was given to interactions between the rate of geologic change and the rate of hydrate melt within the sediment. The latter is controlled by thermal properties of the sediment (resistivity and heat capacity) and hydrates (particularly the latent heat). An additional factor was the rate of change of excess pore water pressures in the sediment in reaction to the expansion of melting hydrate. The results show that the dynamic interactions between these phenomena are equally as important to slope stability as the size of the hypothesized geologic change or the regional slope gradient. Other crucial factors include the water depth, the origin of the hydrate from biologic or reservoir sources, and the strength of the sediment.

Dunlap, W.A. (Texas A and M Univ., College Station (USA)); Hooper, J.R. (Fugro-McClelland, Inc., Houston, TX (USA))

1990-06-01

 
 
 
 
161

All integral slopes can be Seifert fibered slopes for hyperbolic knots  

CERN Multimedia

Which slopes can or cannot appear as Seifert fibered slopes for hyperbolic knots in the 3-sphere S^3? It is conjectured that if r-surgery on a hyperbolic knot in S^3 yields a Seifert fiber space, then r is an integer. We show that for each integer n, there exists a tunnel number one, hyperbolic knot K_n in S^3 such that n-surgery on K_n produces a small Seifert fiber space.

Motegi, K; Motegi, Kimihiko; Song, Hyun-Jong

2005-01-01

162

Slope stability monitoring from microseismic field using polarization methodology  

Directory of Open Access Journals (Sweden)

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).

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

2003-01-01

163

The Alaska North Slope spill analysis  

Energy Technology Data Exchange (ETDEWEB)

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.

Pearson, Leslie [Pearson Consulting LLC (United States)], email: pearson.consulting@mac.com; Robertson, Tim L.; DeCola, Elise [Nuka Research and Planning Group, LLC (United States)], email: timrobertson@nukaresearch.com, email: elise@nukaresearch.com; Rosen, Ira [Alaska Department of Environmental Conservation (United States)], email: ira.rosen@alaska.gov

2011-07-01

164

In-Place Randomized Slope Selection  

DEFF Research Database (Denmark)

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.

Blunck, Henrik; Vahrenhold, Jan

2006-01-01

165

Wildlife response on the Alaska North Slope  

International Nuclear Information System (INIS)

[en] 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

1992-01-01

166

Repeatability Estimates Of Sloped Scattered Data  

Directory of Open Access Journals (Sweden)

Full Text Available Repeatability is the variance in data accumulated under fixed conditions. It is important for quality control as it costs both time and money to recalibrate tools and remanufacture machines. This project compares three methods for approximating the repeatability of a sloped scattered data set. The first method uses a linear approximation, the second involves rotating the data points, and the third calculates distance using right triangles. The methods are compared for both precision and ease of use.

Angelique Waller

2009-01-01

167

Geosynthetic clay liners - slope stability field study  

Energy Technology Data Exchange (ETDEWEB)

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.

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

168

Overview of gas hydrates in submarine slopes  

Energy Technology Data Exchange (ETDEWEB)

Gas hydrates are solid crystalline compounds consisting of hydrogen-bonded water molecules that form a rigid crystal lattice stabilized by encaged gas molecules. Their stability is confined to low-temperature, high-pressure regimes such as those found in permafrost regions and under the seafloor on continental slopes. In-situ natural gas hydrate deposits are typically located in marine sediments at temperatures of 5 to 10 degrees C. The critical factors influencing hydrate formation and stability are pressure, temperature, gas composition, volume of bulk free water, salinity, gas availability, sediment type, and the presence of catalysts or inhibitors. Circumstantial evidence suggests that large submarine landslides along the continental margins can be triggered by the weakening of hydrate bearing sediments. Hydrate dissociation results in loss of solid material, production of free gas, and increased fluid pressures, all which have the effect of reducing sediment strength. These underwater landslides have the potential to destroy offshore equipment, jeopardize safety of personnel, and generate tsunamis. This paper presented recent results and advances on the intersection of gas hydrates and submarine slope stability, with particular reference to the role of gas hydrates in triggering or propagating submarine mass movements. It was concluded that the cause of slope failures is not fully understood because of the complexities of gas hydrates and their interactions with the host sediment, combined with the high cost of laboratory and field investigations. 35 refs., 2 figs.

Grozic, J.L.H. [Calgary Univ., AB (Canada). Dept. of Civil Engineering

2009-07-01

169

Geosensor Data Representation Using Layered Slope Grids  

Directory of Open Access Journals (Sweden)

Full Text Available Environmental monitoring applications are designed for supplying derived and often integrated information by tracking and analyzing phenomena. To determine the condition of a target place, they employ a geosensor network to get the heterogeneous sensor data. To effectively handle a large volume of sensor data, applications need a data abstraction model, which supports the summarized data representation by encapsulating raw data. For faster data processing to answer a user’s queries with representative attributes of an abstracted model, we propose such a data abstraction model, the Layered Slopes in Grid for Sensor Data Abstraction (LSGSA), which is based on the SGSA. In a single grid-based layer for each sensor type, collected data is represented by slope directional vectors in two layered slopes, such as height and surface. To answer a user query in a central monitoring server, LSGSA is used to reduce the time needed to extract event features from raw sensor data as a preprocessing step for interpreting the observed data. The extracted features are used to understand the current data trends and the progress of a detected phenomenon without accessing raw sensor data.

Yongmi Lee; Young Jin Jung; Kwang Woo Nam; Silvia Nittel; Kate Beard; Keun Ho Ryu

2012-01-01

170

Geosynthetic clay liners - slope stability field study  

International Nuclear Information System (INIS)

[en] 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

1997-01-01

171

Toric Slope Stability and Partial Bergman Kernels  

CERN Document Server

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 $Z$.

Pokorny, Florian T

2011-01-01

172

Stability of nuclear crater slopes in rock  

International Nuclear Information System (INIS)

[en] 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

1970-01-01

173

Single beam echosounding: Considerations of depth and seabed slope  

Science.gov (United States)

The topic of depth compensation of single beam echo time series for seabed classification is fairly well studied. The effect of seabed slope has not been publicized. In applications for seabed classification, seabed slope is observed to be associated with classification inaccuracy and failure. In cases of higher slope, single beam bathymetry also becomes inaccurate. A survey of 2 fjords with extreme variation in slope is presented as a representative example and testing bed for investigating slope. The direct effect on seabed echoes is investigated and explained in reference to a simple model of beam-echo geometry. Survey bathymetry is compensated for slope; inaccuracies of up to 5% of depth are corrected, however bottom picking accuracy is diminished in areas of slope and cannot be improved. Surveys of a gas hydrate site and a river will also be presented as applications of these ideas. Early results from BORIS model studies of methods for compensation of slope and depth may also be presented.

Biffard, Ben R.; Chapman, N. Ross; Bloomer, Steve F.; Preston, Jon M.

2005-04-01

174

Tratamento das lesões osteocondrais do talo através da técnica de microperfurações assistidas por artroscopia/ Treatment of osteochondral lesions of the talus by means of thearthroscopy-assisted microperforation technique  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese OBJETIVO: Analisar pacientes acometidos por fratura osteocondral do talo tratados cirurgicamente através de microperfurações assistidas por artroscopia. MÉTODOS: Foi realizado um estudo retrospectivo de 24 pacientes com lesão osteocondral do talo submetidos à microperfurações assistidas por videoartroscopia do tornozelo. Todos os pacientes foram submetidos ao sistema de avaliação da American Orthopaedic Foot & Ankle Society (AOFAS) no pré e pós-operatório. RE (more) SULTADOS: Foram observados 19 homens e cinco mulheres, com idade média de 35,3 anos (mínima de 17 anos e máxima de 54 anos). O tempo mínimo de seguimento foi de dois anos (máximo de 39 meses). Todos os pacientes apresentaram melhora do escore da AOFAS após o procedimento cirúrgico, com média de elevação do escore em torno de 22,5 pontos. CONCLUSÃO: A técnica de microperfurações assistidas por videoartroscopia consiste em boa opção para o tratamento das lesões osteocondrais do talo e fornece bons resultados funcionais. Abstract in english OBJECTIVE: To evaluate patients affected by osteochondral fractures of the talus who were treated surgically by means of arthroscopy-assisted microperforation. METHODS: A retrospective study was carried out on 24 patients with osteochondral lesions of the talus who underwent microperforation assisted by videoarthroscopy of the ankle. They were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) score system before and after the operation. RESULTS: Ther (more) e were 19 men and 5 women, with a mean age of 35.3 years (minimum of 17 years and maximum of 54 years). The minimum follow-up was two years (maximum of 39 months). All the patients showed an improvement in AOFAS score after surgery, with an average improvement of around 22.5 points. CONCLUSION: Videoarthroscopy-assisted microperforation is a good option for treating osteochondral lesions of the talus and provides good functional results.

Lima, Everton de; Queiroz, Felipe de; Lopes Júnior, Osmar Valadão; Spinelli, Leandro de Freitas

2011-01-01

175

Tratamento das lesões osteocondrais do talo através da técnica de microperfurações assistidas por artroscopia Treatment of osteochondral lesions of the talus by means of thearthroscopy-assisted microperforation technique  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: Analisar pacientes acometidos por fratura osteocondral do talo tratados cirurgicamente através de microperfurações assistidas por artroscopia. MÉTODOS: Foi realizado um estudo retrospectivo de 24 pacientes com lesão osteocondral do talo submetidos à microperfurações assistidas por videoartroscopia do tornozelo. Todos os pacientes foram submetidos ao sistema de avaliação da American Orthopaedic Foot & Ankle Society (AOFAS) no pré e pós-operatório. RESULTADOS: Foram observados 19 homens e cinco mulheres, com idade média de 35,3 anos (mínima de 17 anos e máxima de 54 anos). O tempo mínimo de seguimento foi de dois anos (máximo de 39 meses). Todos os pacientes apresentaram melhora do escore da AOFAS após o procedimento cirúrgico, com média de elevação do escore em torno de 22,5 pontos. CONCLUSÃO: A técnica de microperfurações assistidas por videoartroscopia consiste em boa opção para o tratamento das lesões osteocondrais do talo e fornece bons resultados funcionais.OBJECTIVE: To evaluate patients affected by osteochondral fractures of the talus who were treated surgically by means of arthroscopy-assisted microperforation. METHODS: A retrospective study was carried out on 24 patients with osteochondral lesions of the talus who underwent microperforation assisted by videoarthroscopy of the ankle. They were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) score system before and after the operation. RESULTS: There were 19 men and 5 women, with a mean age of 35.3 years (minimum of 17 years and maximum of 54 years). The minimum follow-up was two years (maximum of 39 months). All the patients showed an improvement in AOFAS score after surgery, with an average improvement of around 22.5 points. CONCLUSION: Videoarthroscopy-assisted microperforation is a good option for treating osteochondral lesions of the talus and provides good functional results.

Everton de Lima; Felipe de Queiroz; Osmar Valadão Lopes Júnior; Leandro de Freitas Spinelli

2011-01-01

176

On a slow moving slope in Hong Kong  

Digital Repository Infrastructure Vision for European Research (DRIVER)

?This thesis investigates the mechanism of a slow moving landslide through a case study based on a full-scale field monitoring conducted in a slow moving natural slope. The slope is gentle and located within a southwest-trending valley which is about 500 meters long with an average slope angle of 17...

Xu, Kai; ??

177

The Jones polynomial and boundary slopes of alternating knots  

CERN Multimedia

We show for an alternating knot the minimal integral boundary slope is given by the signature plus twice the minimum degree of the Jones polynomial and the maximal integral boundary slope is given by the signature plus twice the maximum degree of the Jones polynomial. For alternating Montesinos knots, these are the minimal and maximal boundary slopes.

Curtis, Cynthia L

2009-01-01

178

Distinct Element Modelling of Mahabaleshwar Road Cut Hill Slope  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

179

Hydrocarbon prospectivity of the Argentine Continental Slope  

Energy Technology Data Exchange (ETDEWEB)

A rift basin containing stratigraphic and structural closures is developed along the Argentine slope over a distance of some 1000 km and area of 50,000 km[sup 2] in potentially exploitable water depths of 200 to 1500 m. No wells exist on this part of the continental margin. Rifting began during the Late Triassic/Jurassic and ended in Early Cretaceous. The first marine seaways flooded the Rift alluvial plains and lake. In Hauterian-Barrenian time, low circulation marine conditions with oxygen deficiency prevailed up to Rio Grande/Walvis Ridge flooding in part the coastal pull-apart basins. A major marine transgression in the Maastrichtian formed a widespread seal over the entire shelf and slope area. Four play types were identified: (1) a major north-east trending elongate delta system sourced inland from the San Julien (N. Malvinas) Basin and deposited on the southern Patagonian shelf and rise, (2) reworked deltaic barrier sands accumulated along the crest of the Outer Basement Ridge, (3) The Outer Basement Ridge, a major structural closure 400 km long, and (4) a series of margin-parallel rift systems in the offshore region between the 200 m and 1500 m isobaths. Regional seismic data and geological correlations suggest that oil prone source rocks are likely in the Middle and Upper Jurassic and Cretaceous formations. Source rocks are probably mature east and west of the Outer Basement Ridge and in the easterndepocenter of the Colorado Basin. Eastward migration from Jurassic age lacustrine source rocks in the Colorado Basin may have charged traps along the crest of the Outer Basement Ridge. Westward directed migration from deeply buried Aptian age marine source rocks in the Atlantic basins has probably charged prospective stratigraphic and structural traps in a suite of coast-parallel grabens developed on the Argentine continental shelf and slope. The Argentine offshore region, therefore, offers significant encouragement as a productive hydrocarbon province.

Light, M.P.R.; Keeley M.L.; Maslanyj, M.P.; Urien, C.M.; Hoggs, S.L.

1993-02-01

180

Slope equalities for genus 5 surface fibrations  

CERN Document Server

K. Konno proved a slope equality for fibred surfaces with fibres of odd genus and general fibre of maximal gonality. More precisely he found a relation between the invariants of the fibration and certain weights of special fibres (called the Horikawa numbers). We give an alternative and more geometric proof in the case of a genus 5 fibration, under generality assumptions. In our setting we are able to prove that the fibre with positive Horikawa numbers are precisely the trigonal ones, we compute their weights explicitly and thus we exhibit explicit examples of regular surfaces with assigned invariants and Horikawa numbers.

Tenni, Elisa

2010-01-01

 
 
 
 
181

Regional method to assess offshore slope stability.  

Science.gov (United States)

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

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

1986-01-01

182

Transhumanism, medical technology and slippery slopes.  

UK PubMed Central (United Kingdom)

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.

McNamee MJ; Edwards SD

2006-09-01

183

Transhumanism, medical technology and slippery slopes.  

Science.gov (United States)

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

McNamee, M J; Edwards, S D

2006-09-01

184

Slope stability study for optimum design of an opencast project  

Energy Technology Data Exchange (ETDEWEB)

The stability of an opencast mine slope, investigated by the limit equilibrium method, indicates that 148m deep open pit is stable with 60{sup o} overall slope angle. Geotechnical mapping was undertaken to determine the critical orientation of structural discontinuities. Geomechanical properties were determined in the laboratory and subsequently modified to approximate those of in situ rock mass. Sensitivity analysis was done to determine the influence of the slope design parameters on the safety factor. It was also used in determining the most suitable remedial measure for the critical slope. Slope monitoring did not reveal any movement in and around the pit.

Singh, V.K.

2006-01-15

185

Miniature hole-disk structure for side slope greeneng  

UK PubMed Central (United Kingdom)

The utility model relates to a mini-type plug tray structure used for slope greening. The technical problem to be solved by the utility model is to provide a mini-type plug tray structure for slope greening, which can carry out the ecological greening at the flat or high and precipitous slopes without gradient limitation and have low cost and short construction time. The technical scheme for solving such problem is that: the mini-type plug tray structure for slope greening comprises a flat and smooth connection board and a mini-size plug tray connected to the connection board all sides of the connection board and around the mini-type plug tray are provided with a connection belt, on which anchor reinforcement holes are provided the mini-type plug tray takes the shape of a chamber stretching out of the connection board, wherein the faced of the chamber is drilled with drainage holes, while the reverse side of which is provided with root system guiding holes. The utility model can be used for various excavations in the filed of highroad, railway slope, hydropower project slope, industrial and civil architecture slope, mine slope and large scale project construction slope, etc, or used to solve the slope controlling and managing problems, such as natural flat slope greening and environmental disruption recovery.

LI SHUYI LV

186

Kinetics of cross-slope running.  

UK PubMed Central (United Kingdom)

The purpose of the present study was to identify kinetic responses to running on mediolaterally elevated (cross-sloped) running surfaces. Ground reaction forces (GRFs), GRF lever arms and joint moment characteristics of 19 male runners were analyzed when running at 3.5m/s on a custom-made, tiltable runway. Tilt angles of 3° and 6° for medial and lateral elevation were analyzed using a 10 camera Vicon Nexus system and a force platform. The point of force application of the GRF showed a systematic shift in the order of 1-1.5cm to either the lateral or medial aspect of the foot for lateral or medial inclinations, respectively. Consequently, the strongest significant effects of tilt orientation and level on joint kinetics and ground reaction force lever arms were identified at the ankle, knee and hip joint in the frontal plane of movement. External eversion moments at the ankle were significantly increased by 35% for 6° of lateral elevation and decreased by 16% for 6° of medial elevation. Altering the cross-slope of the running surface changed the pattern of ankle joint moments in the transversal plane. Effect sizes were on average larger for laterally elevated conditions, indicating a higher sensitivity of kinetic parameters to this kind of surface tilt. These alterations in joint kinetics should be considered in the choice of the running environment, especially for specific risk groups, like runners in rehabilitation processes.

Willwacher S; Fischer KM; Benker R; Dill S; Brüggemann GP

2013-09-01

187

Foam drainage on a sloping weir.  

Science.gov (United States)

Foam drainage is considered in a froth flotation tank with a sloping weir. The drainage is shown to be gravity dominated in most of the foam, except for thin boundary layers at the base of the froth, and along the sloping weir. The mathematical reason for the boundary layers is that capillary suction is a much weaker effect than gravity, but cannot be ignored altogether, because it represents a singular perturbation. The relative weakness of capillary suction with respect to gravity is represented by a key dimensionless parameter, denoted K, which satisfies Kspeed jet. The jet velocity scales with the (2/3) power of distance from the weir lip, and is O(K(-2/3)) times larger than the typical velocity in the gravity-dominated flow in the bulk of the flotation tank. The liquid volume fraction in the jet is likewise O(K(-2/3)) larger than that in the bulk. Across the jet, the foam exhibits a known profile of liquid fraction vs. distance from the weir: this is known as the equilibrium profile. The foam requires a distance equivalent to O(K(4/3)) weir lengths to dry out significantly from the wetness value on the weir, but a larger O(K) distance to fall back to a wetness comparable with that in the bulk of the froth. PMID:15015124

Grassia, P; Neethling, S J; Cilliers, J J

2002-08-01

188

Slope stability analysis of Valles Marineris, Mars  

Science.gov (United States)

Valles Marineris (VM) in the equatorial area of Mars exhibits several gravitational failures which resulted in a series of large landslides up to several hundred cubic kilometers in volume. Questions arise as to forces at play and rock strength in the stability of the walls of VM. In this work we address the stability analysis of the walls of VM by considering the strength of the materials of the chasma walls and the causes of landslides. Using finite element calculations and the limit analysis upper bound method, we explore the range of cohesion and friction angle values associated to realistic failure geometries, and compare predictions with the classical Culmann's wedge model. Our analysis is based both on synthetic, simplified slope profiles and also on the real shape of the walls of VM taken from the MOLA topographic data. Validation of the calibrated cohesion and friction angle values is performed by comparing the computed unstable cross sectional areas with the observed pre- and post-failure profiles and estimated failure surface geometry. This offers a link between rock mass properties, slope geometry and volume of the observed failure. Pseudo-static seismic analyses generated another set of dimensionless charts. Our pseudo-static analyses show that low seismicity events induced by meteoroids impacts compatible with the size of craters could be a cause for some of the observed landslides if poor rock properties for VM is assumed.

Vittorio De Blasio, Fabio; Battista Crosta, Giovanni; Castellanza, Riccardo; Utili, Stefano

2013-04-01

189

Sequelas a longo prazo de fracturas do corpo e colo do astrágalo Long-term results of body and neck talus fractures  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: As fracturas do colo e corpo do astrágalo são lesões infrequentes. O objectivo deste estudo é avaliar a prevalência de sequelas a longo prazo. MÉTODOS: Foi feita uma análise retrospectiva que incluiu um total de 11 doentes sujeitos a tratamento cirúrgico por fracturas do corpo ou colo do astrágalo entre Janeiro de 1997 e Dezembro de 2005. A avaliação final foi clínica (utilizando a escala AOFAS) e radiológica. RESULTADOS: O seguimento médio foi 58,5 meses. A prevalência de lesões ósseas associadas foi de 60% (6/10). O resultado AOFAS médio foi 72 [19-100] pontos. A necrose avascular e/ou artrose pós-traumática ocorreu em metade dos doentes. A qualidade da redução cirúrgica, as fracturas do corpo e a ausência de alterações degenerativas relacionaram-se com melhores resultados funcionais. As fracturas do colo, a osteonecrose e a presença de artrose pós-traumática conduziram a piores resultados. CONCLUSÃO: Há um grande potencial para sequelas tardias e compromisso funcional devido a artrose e dor crónica após esse tipo de fracturas. A redução anatómica cirúrgica é a melhor hipótese de as evitar, mas não é infalível. A taxa de necrose avascular relaciona-se com o grau de desvio inicial da fractura, mas a sua ocorrência em cada caso específico é imprevisível.OBJECTIVES: Talar neck and body fractures are unusual fractures. The purpose of this study is to determine the prevalence of long term results. MATERIAL AND METHODS: A retrospective analysis was carried out including 11 patients that underwent surgical treatment for body or neck talus fractures between January 1997 and December 2005. Final follow-up examination included a clinical evaluation (AOFAS score) and standard radiographs. RESULTS: The mean follow-up time was 58.5 months. The prevalence of associated fractures was 60% (6/10). Overall AOFAS score averaged 72 [19-100]. Avascular necrosis and posttraumatic arthritis were present in half of the patients. Quality of surgical reduction, body fractures and absence of degenerative changes were correlated with better functional results. Neck fractures, osteonecrosis and posttraumatic arthritis led to inferior results. CONCLUSION: There is a great potential for long term functional impairment due to posttraumatic arthritis and chronic pain in this kind of fracture. Anatomic surgical reduction is the best chance to avoid them but it is not infallible. The avascular necrosis rate correlates with initial fracture displacement, but its occurrence in each specific case is unpredictable.

Ricardo Jorge Gomes de Sousa; Marta Maria Teixeira de Oliveira Massada; Manuel Alexandre Negrais Pinho Gonçalves Pereira; Isabel Maria Gonçalves Costa; José Fernando Souzellas da Costa e Castro

2009-01-01

190

Sequelas a longo prazo de fracturas do corpo e colo do astrágalo/ Long-term results of body and neck talus fractures  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese OBJETIVO: As fracturas do colo e corpo do astrágalo são lesões infrequentes. O objectivo deste estudo é avaliar a prevalência de sequelas a longo prazo. MÉTODOS: Foi feita uma análise retrospectiva que incluiu um total de 11 doentes sujeitos a tratamento cirúrgico por fracturas do corpo ou colo do astrágalo entre Janeiro de 1997 e Dezembro de 2005. A avaliação final foi clínica (utilizando a escala AOFAS) e radiológica. RESULTADOS: O seguimento médio foi 58, (more) 5 meses. A prevalência de lesões ósseas associadas foi de 60% (6/10). O resultado AOFAS médio foi 72 [19-100] pontos. A necrose avascular e/ou artrose pós-traumática ocorreu em metade dos doentes. A qualidade da redução cirúrgica, as fracturas do corpo e a ausência de alterações degenerativas relacionaram-se com melhores resultados funcionais. As fracturas do colo, a osteonecrose e a presença de artrose pós-traumática conduziram a piores resultados. CONCLUSÃO: Há um grande potencial para sequelas tardias e compromisso funcional devido a artrose e dor crónica após esse tipo de fracturas. A redução anatómica cirúrgica é a melhor hipótese de as evitar, mas não é infalível. A taxa de necrose avascular relaciona-se com o grau de desvio inicial da fractura, mas a sua ocorrência em cada caso específico é imprevisível. Abstract in english OBJECTIVES: Talar neck and body fractures are unusual fractures. The purpose of this study is to determine the prevalence of long term results. MATERIAL AND METHODS: A retrospective analysis was carried out including 11 patients that underwent surgical treatment for body or neck talus fractures between January 1997 and December 2005. Final follow-up examination included a clinical evaluation (AOFAS score) and standard radiographs. RESULTS: The mean follow-up time was 58.5 (more) months. The prevalence of associated fractures was 60% (6/10). Overall AOFAS score averaged 72 [19-100]. Avascular necrosis and posttraumatic arthritis were present in half of the patients. Quality of surgical reduction, body fractures and absence of degenerative changes were correlated with better functional results. Neck fractures, osteonecrosis and posttraumatic arthritis led to inferior results. CONCLUSION: There is a great potential for long term functional impairment due to posttraumatic arthritis and chronic pain in this kind of fracture. Anatomic surgical reduction is the best chance to avoid them but it is not infallible. The avascular necrosis rate correlates with initial fracture displacement, but its occurrence in each specific case is unpredictable.

Sousa, Ricardo Jorge Gomes de; Massada, Marta Maria Teixeira de Oliveira; Pereira, Manuel Alexandre Negrais Pinho Gonçalves; Costa, Isabel Maria Gonçalves; Castro, José Fernando Souzellas da Costa e

2009-10-01

191

Development of Probabilistic Safety Assessment Considering Slope Collapse by Earthquake  

International Nuclear Information System (INIS)

[en] 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)

2007-11-14

192

Dendrogeomorphic approach to estimating slope retreat, Maxey Flats, Kentucky  

International Nuclear Information System (INIS)

[en] 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

1990-01-01

193

Laboratory Granular Flows generated by Slope Failures  

Science.gov (United States)

A series of flume experiments has been set up to analyze the behavior of water sand mixture flows, as a consequence of slope failures induced by water table raising and rainfall. The flows initially accelerated but at a certain stage of the process, unsteady deposition of the sand occurred, preceded by the transformation of the movement from flow to sliding. The comparison of such phenomena with other flume experiments, performed in similar conditions, showed that differences in flow behavior are dependent on a variety of aspects that are difficult to take into account. A numerical modeling of laboratory flows has been performed, using a cellular automata model based on the grain inertia regime. Despite the relatively good agreement between modeled and experimental phenomena, the study shows the difficulties of taking the actual behavior of granular flows into account.

Deangeli, C.

2008-02-01

194

Seismic Stability of Reinforced Soil Slopes  

DEFF Research Database (Denmark)

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 impact of the most significant parameters involved, such as the flexibility of the sliding system, the mechanical properties of the soil and of the geosynthetics material, the frequency content of the excitation and the interface shear strength.

Tzavara, I.; Zania, Varvara

2012-01-01

195

Pomeron intercept and slope: A QCD connection  

International Nuclear Information System (INIS)

The ratio r of intercept to slope of the Pomeron trajectory is derived in a QCD inspired parton model approach to diffraction based on a (re)normalization of the pp/pp single-diffractive cross section designed to enforce unitarity constraints by eliminating overlapping rapidity gaps. As the collision energy increases, the renormalized single-diffractive cross section tends to a constant which depends on the ratio r. Identifying the constant as the ?o of the total cross section, ?=?o?s?, yields the ratio r in terms of measured parameters that can be phenomenologically expressed in terms of the pion mass and QCD color factors. The result agrees with the measured value of r.

2009-12-01

196

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.

1990-01-01

197

ASPECTS OF DRIP IRRIGATION ON SLOPES  

Directory of Open Access Journals (Sweden)

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.

Oprea Radu; Daniel Bucur

2010-01-01

198

Nocturnal flow on a western Colorado slope  

Energy Technology Data Exchange (ETDEWEB)

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 {times} 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.

Leone, J.M. Jr.; Gudiksen, P.H.

1990-04-01

199

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 undermine the stability of the slopes. The present study incorporates the stability analysis of road cut slopes along NH-109 which goes to holy shrine of Kedarnath. Slope failure is not only a phenomenon of rainy season but it has also been encountered even in dry season. The study area experiences high vehicular traffic especially from March to August due to pilgrims since it is the only road to Kedarnath. The distance of about 20 km between Rudraprayag and Agastmuni has been investigated. The continuous slope mass rating (CSMR) technique has been used for slope stability analysis at five different locations. CSMR is modification of original slope mass rating (SMR) proposed by Romana which is based on well established rock mass rating (RMR) technique. Kinematic analysis was also carried out to evaluate these sites for types of failure and its potential failure directions. The potentially vulnerable sites were identified. The results indicate that the CSMR technique may be exploited to assess the stability of rock slopes in the Himalayan territory.

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

2011-01-01

200

Effect of slope and footwear on running economy and kinematics.  

Science.gov (United States)

Lower energy cost of running (Cr) has been reported when wearing minimal (MS) vs traditional shoes (TS) on level terrain, but the effect of slope on this difference is unknown. The aim of this study was to compare Cr, physiological, and kinematic variables from running in MS and TS on different slope conditions. Fourteen men (23.4?±?4.4 years; 177.5?±?5.2 cm; 69.5?±?5.3?kg) ran 14 5-min trials in a randomized sequence at 10?km/h on a treadmill. Subjects ran once wearing MS and once wearing TS on seven slopes, from -8% to +8%. We found that Cr increased with slope gradient (P?stemmed from the difference in shoe mass considering that the Cr difference was independent of slope gradient and that the between-footwear kinematic alterations with slope provided limited explanations. PMID:23438190

Lussiana, T; Fabre, N; Hébert-Losier, K; Mourot, L

2013-02-26

 
 
 
 
201

On barotropic and baroclinic tides over an arbitrary sloping topography  

Directory of Open Access Journals (Sweden)

Full Text Available Some theoretical concepts about the frictionless dynamics of propagation of the barotropic tide over two-dimensional continental slopes of arbitrary shape are developed. A numerical procedure which generalizes the exact solution obtained over a rectilinear sloping topography is given. This technique can be applied to compute the harmonic components of the barotropic tide everywhere over sloping bottom contours of any shape. It permits in particular the avoidance of discontinuities at the boundaries of rectilinear-continental-slope profiles. The barotropic tidal results are used afterwards to calculate the barotropic forcing for the generation of internal tides. Numerical experiments are performed to study the interaction between the tide and some typical sloping topographies. A three-layered model is used for this purpose. Results are compared with those previously obtained over a rectilinear continental slope.

J. Y. Le Tareau; R. Maze

0000-01-01

202

Distinct Element Modelling of Mahabaleshwar Road Cut Hill Slope  

Directory of Open Access Journals (Sweden)

Full Text Available 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 was carried out for both the dry and saturated conditions. The distinct element analysis of the hill slope demonstrates it to be marginally stable under dry condition, while for the saturated condition, the hill slope fails along well defined joint planes.

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

2012-01-01

203

Tidal propagation in an oceanic island with sloping beaches  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, a new analytical solution for describing the tide-induced groundwater fluctuations in oceanic islands with finite length and different slopes of the beaches is developed. Unlike previous solutions, the present solution is not only applicable for a semi-infinite coastal aquifer, but also for an oceanic island with finite length and different sloping beaches. The solution can be used to investigate the effect of higher-order components and beach slopes on the water table fluctuations. The results demonstrate the effect of higher-order components increases with the shallow water parameter or amplitude parameter and the water table level increases as beach slopes decrease.

Y.-C. Chang; D.-S. Jeng; H.-D. Yeh

2010-01-01

204

Slope Stability and Exceptional Divisors of High Genus  

CERN Multimedia

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. We also prove that a destabilising divisor can never be nef, and as an application give an example of a surface that is slope stable but not K-stable.

Panov, Dmitri

2007-01-01

205

The Role of Slope Geometry on Flowslide Occurrence  

Directory of Open Access Journals (Sweden)

Full Text Available The paper reports a study aimed to the prediction of susceptibility to flowslide of granular soil slopes as a consequence of the in situ state of stress. In particular, the slope geometry has been investigated as a factor influencing the initial state of stress. For this purpose the results of numerical models, performed by a finite different approach (FLAC), allowed the complete definition, in any point of the slope, of the stress conditions by changing slope height and inclination. By relating this state of stress to parameters used to describe potential for liquefaction of loose granular soils a chart of instability has been set up.

Chiara Deangeli

2007-01-01

206

The Key Technologies of Steep Rock Slope Protection  

Directory of Open Access Journals (Sweden)

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.

Hongliang Deng; Tingting Ni; Kaijiang Chen; Mingyan Zhu

2013-01-01

207

Nocturnal flow on a western Colorado slope  

Energy Technology Data Exchange (ETDEWEB)

The Department of Energy sponsored Atmospheric 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 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 from a numerical simulation done as part of this study. 4 refs., 7 figs.

Leone, J.M. Jr.; Gudiksen, P.H.

1990-06-01

208

Effect of slope and footwear on running economy and kinematics.  

UK PubMed Central (United Kingdom)

Lower energy cost of running (Cr) has been reported when wearing minimal (MS) vs traditional shoes (TS) on level terrain, but the effect of slope on this difference is unknown. The aim of this study was to compare Cr, physiological, and kinematic variables from running in MS and TS on different slope conditions. Fourteen men (23.4?±?4.4 years; 177.5?±?5.2 cm; 69.5?±?5.3?kg) ran 14 5-min trials in a randomized sequence at 10?km/h on a treadmill. Subjects ran once wearing MS and once wearing TS on seven slopes, from -8% to +8%. We found that Cr increased with slope gradient (P?slope did not influence the Cr difference between MS and TS. In MS, contact times were lower (P?slope gradients, and plantar-foot angles - and often ankle plantar-flexion (P?=?0.01) - were greater (P?slope gradient and that the between-footwear kinematic alterations with slope provided limited explanations.

Lussiana T; Fabre N; Hébert-Losier K; Mourot L

2013-08-01

209

In situ characterization of flows in a fractured unstable slope  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the case of large unstable mountain slopes, the spatial repartition of the saturated zones influence the pressure repartitions in the massif and the slope stability. This contribution proposes an evaluation of water origin and pressure transit time of groundwater flows from hydrochemical and isot...

Binet, Stéphane; Mudry, Jacques; Scavia, Claudio; Campus, Stefano; Bertrand, Catherine; Guglielmi, Yves

210

Wave overtopping resistance of grassed dike slopes in Vietnam  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The resistance of various grassed slopes against wave overtopping has been appraised by means of the Wave Overtopping Simulator in situ for a couple of years in Viet Nam. Destructive test results show that a dike slope covered with grass could suffer a certain overtopping discharge not smaller than ...

Trung, L.H.; Van der Meer, J.W.; Luong, N.Q.; Verhagen, H.J.; Schiereck, G.J.

211

Katabatic flow observations over a steep alpine slope  

Science.gov (United States)

Katabatic flows, or downslope drainage flows, are thermally driven winds generated over sloping terrain when the surface is colder than the adjacent air and synoptic forcing is weak. This near-surface temperature inversion generates a buoyancy field such that denser, cooler air near the surface tends to sink down the slope and form the katabatic flow. Often these flows can be exploited for wind energy, and they are important in predicting pollution transport in mountainous regions and the formation of large cold air pools in valleys and basins. Mean characteristics of katabatic flows over gentle slopes are well documented. However, small-scale observations of turbulence inside the katabatic jet are less common, especially over very steep slopes in highly complex topography. Summertime measurements over a steep slope (36.5°) in a narrow alpine valley (Val Ferret, Switzerland) were taken with the aim of better understanding the near-surface turbulent fluxes that govern the local slope flows. Here, a weak katabatic jet with a height less than 1 m characterizes the mean flow. High-resolution, near-surface temperature measurements suggest a shallow internal boundary layer within the katabatic layer. Additionally, the turbulent heat flux varies significantly over the 6 m measurement layer. Hence, Monin-Obukhov Similarity theory (MOST) may be invalid for steep slopes. Turbulent statistics such as velocity and temperature variances, fluxes of momentum and heat, turbulence kinetic energy (TKE), and turbulent Prandtl number are compared to those obtained in large eddy simulations (LES) of idealized steep sloping terrain.

Oldroyd, Holly; Pardyjak, Eric; Calaf, Marc; Giometto, Marco; Huwald, Hendrik; parlange, Marc

2013-04-01

212

Optimal designs for estimating the slope of a regression  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the common linear regression model we consider the problem of designing experiments for estimating the slope of the expected response in a regression. We discuss locally optimal designs, where the experimenter is only interested in the slope at a particular point, and standardized minimax optimal...

Dette, Holger; Melas, Viatcheslav B.

213

Writing a Slope-Intercept Equation from a Graph  

Science.gov (United States)

This step by step lesson from Math Ops demonstrates how to write a slope-intercept equation from a graph. Students can read the text on the slides or follow along as it is read aloud. The slope-intercept format of a line is explained as well as how to write an equation for a line. Three examples are given.

2011-01-01

214

Slope Stability Evaluations by Limit Equilibrium and Finite Element Methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis deals with slope stability evolutions carried out by commonly used limit equilibrium (LE) and finite element (FE) methods. The study utilizes two LE based software (SLOPE/W and SLIDE) and one FE based software (PLAXIS). The principal difference between these two analyses approaches is th...

Aryal, Krishna Prasad

215

Assessing slope stability in unplanned settlements in developing countries.  

Science.gov (United States)

Unplanned housing in developing countries is often located on steep slopes. Frequently no building code is enforced for such housing and mains water is provided with no drainage provision. Both of these factors can be particularly significant in terms of landslide risk if, as is so often the case, such slopes lack any planned drainage provision. There is thus a need to develop a model that facilitates the assessment of slope stability in an holistic context, incorporating a wide range of factors (including surface cover, soil water topographic convergence, slope loading and point source water leakage) in order that appropriate advice can be given as to the general controls on slope stability in such circumstances. This paper outlines a model configured for this specific purpose and describes an application to a site in St. Lucia, West Indies, where there is active slope movement in an unplanned housing development on relatively steep topography. The model findings are in accord with the nature of the current failure at the site, provide guidance as to the significance of slope drainage and correspond to inferences drawn from an application of resistance envelope methods to the site. In being able to scenario test a uniquely wide range of combinations of factors, the model structure is shown to be highly valuable in assessing dominant slope stability process controls in such complex environments. PMID:17107745

Anderson, Malcolm G; Holcombe, Liz; Renaud, Jean-Philippe

2006-11-14

216

Assessing slope stability in unplanned settlements in developing countries.  

UK PubMed Central (United Kingdom)

Unplanned housing in developing countries is often located on steep slopes. Frequently no building code is enforced for such housing and mains water is provided with no drainage provision. Both of these factors can be particularly significant in terms of landslide risk if, as is so often the case, such slopes lack any planned drainage provision. There is thus a need to develop a model that facilitates the assessment of slope stability in an holistic context, incorporating a wide range of factors (including surface cover, soil water topographic convergence, slope loading and point source water leakage) in order that appropriate advice can be given as to the general controls on slope stability in such circumstances. This paper outlines a model configured for this specific purpose and describes an application to a site in St. Lucia, West Indies, where there is active slope movement in an unplanned housing development on relatively steep topography. The model findings are in accord with the nature of the current failure at the site, provide guidance as to the significance of slope drainage and correspond to inferences drawn from an application of resistance envelope methods to the site. In being able to scenario test a uniquely wide range of combinations of factors, the model structure is shown to be highly valuable in assessing dominant slope stability process controls in such complex environments.

Anderson MG; Holcombe L; Renaud JP

2007-10-01

217

Application of the Finite Element Method to Slope Stability  

Science.gov (United States)

This document outlines the capabilities of the finite element method in the analysis of slope stability problems. A description of the constitutive laws of material behavior such as the Mohr-Coulomb failure criterion, and material properties input parameters, required to adequately model slope failure is given as well.

2008-09-23

218

Design charts for the stability analysis of unsaturated soil slopes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Simple limit equilibrium analyses can be performed to determine the Factor of Safety (FOS) against slope failure of unsaturated soil slopes. However, many of the input parameters needed for these analyses are highly variable, and the FOS value obtained is critically dependent on assumptions made by ...

Gavin, Kenneth; Xue, Jianfeng

219

Three-dimensional kinematic controls on rock slope stability conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 geome...

Brideau, Marc-Andre

220

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...

 
 
 
 
221

Method of vegetation slope pavement of level fluctuation zone  

UK PubMed Central (United Kingdom)

A method for preparing plant slope protection on rising and falling limb of water surface applies scheme of sowing amphibious plant seeds as main then planting amphibious plant nursery stock as auxiliary on slope of rising and falling limb to form ecological protective plant group configured by musky and grass with water logging proof and draught enduring nature.

ZHANG YUCHANG ZHANG

222

Spectral Slope and Kolmogorov Constant of MHD Turbulence  

International Nuclear Information System (INIS)

The spectral slope of strong MHD turbulence has recently been a matter of controversy. While the Goldreich-Sridhar model predicts a -5/3 slope, shallower slopes have been observed in numerics. We argue that earlier numerics were affected by driving due to a diffuse locality of energy transfer. Our highest-resolution simulation (30722x1024) exhibited the asymptotic -5/3 scaling. We also discover that the dynamic alignment, proposed in models with -3/2 slope, saturates and cannot modify the asymptotic, high Reynolds number slope. From the observed -5/3 scaling we measure the Kolmogorov constant CKA=3.27±0.07 for Alfvenic turbulence and CK=4.2±0.2 for full MHD turbulence, which is higher than the hydrodynamic value of 1.64. This larger CK indicates inefficient energy transfer in MHD turbulence, which is in agreement with diffuse locality.

2011-02-18

223

Alterações radiográficas do tálus no pé torto congênito após liberação cirúrgica pela técnica de McKay Radiographic changes of the talus in congenital clubfoot after surgical release using the mckay procedure  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: Analisar as alterações morfológicas do tálus após o tratamento cirúrgico do pé torto congênito pela técnica de McKay. MÉTODOS: Foram analisadas, retrospectivamente, radiografias em perfil com carga dos pés de 14 pacientes com pé torto congênito unilateral submetidos ao tratamento pela técnica de McKay por dupla incisão. Todos os pacientes foram operados pelo mesmo cirurgião, com média de 6,53 anos entre a cirurgia e a radiografia. Comparamos as características do tálus dos pés operados com os parâmetros radiográficos dos pés contralaterais. Avaliamos a presença de deformidade do dômus e da cabeça do tálus (avaliação da esfericidade), a altura e o comprimento do tálus, a presença e grau de subluxação do navicular, a alteração do ângulo de Gissane e o padrão do trabeculado ósseo. RESULTADOS: Alterações da cabeça do tálus ocorreram em 92,8% dos casos; do dômus, em 92,8%; e do trabeculado, em 100%. A relação entre o comprimento do tálus do pé operado sobre o contralateral variou de 0,61 a 0,88 (média de 0,79; DP = 0,09), e da altura de 0,57 a 0,98 (média de 0,82; DP = 0,12). O ângulo de Gissane aumentou em todos os pés operados, e todos apresentaram subluxação do navicular, com índice variando de 6,43 a 59,75% (média de 26,34%; DP = 16,66%). CONCLUSÕES: Alterações talares ocorreram em 100% dos pés tratados pela técnica de McKay. Estabelecer parâmetros radiográficos para descrever e quantificar essas deformidades mostrou-se viável através de técnicas simples e de fácil execução.OBJECTIVE: To analyze the morphologic changes of the talus after surgical treatment of congenital clubfoot using the McKay procedure. METHODS: We retrospectively analyzed lateral standing radiographs of the feet in 14 patients with unilateral clubfoot treated by the McKay procedure. All patients were operated on by the same surgeon, with an average of 6.53 years between surgery and the radiograph. We compared the characteristics of the talus between the operated foot and the contralateral foot. We evaluated the deformity of the domus and the head of the talus (sphericity evaluation), the talar length and height, the presence and percentage of navicular subluxation, changes in the Gissane angle, and the trabecular pattern of the bone. RESULTS: Deformities of the head of the talus were observed in 92.8% of the patients; of the domus in 92.8%; and of the trabecular pattern in 100%. The ratio between the talar lengths of the operated foot and the contralateral foot ranged from 0.61 to 0.88 (Mean 0.79, SD = 0.09), while the height ratio ranged from 0.57 to 0.98 (Mean 0.82, SD = 0.12). The Gissane angle was increased in all of the operated feet, which also showed some degree of navicular subluxation, ranging from 6.43 to 59.75% (Mean 26.34%, SD = 16.66%). CONCLUSIONS: Abnormal talar findings were observed in 100% of the feet treated using the McKay procedure. The establishment of radiographic parameters to describe and quantify these deformities was feasible through simple and easy techniques.

José Antonio Pinto; Andréa Canizares Hernandes; Thais de Paula Buchaim; Francesco Camara Blumetti; Carla Chertman; Patrícia Corey Yamane; Artur da Rocha Corrêa Fernandes

2010-01-01

224

Research on the Slope Protection Mechanism of Roots  

Directory of Open Access Journals (Sweden)

Full Text Available 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 tension were studied and the influence to the stability of the slope was discussed in this study. The results show that the mean ultimate tension of roots is 7.19~29.96 N. The mean tension of shrub roots is 2~4 times greater than that of herb roots. The ultimate tension of the same plant roots increases with the diameter significantly. To the range of improvement, Shrub roots exceed herb ones. It also indicates that the mean tensile strength of roots are 24.48~74.25 MPa. Compared with the steel HRB235, the tensile strength of herb roots is as great as 1/5~1/3, while Shrub roots is about 1/10~1/5. The slope stability coefficient with plant growing is a positive correlation with roots tension and root number through the sliding surface and is a negative correlation with plants weight. In addition, the slope stability coefficient is related to plant density and root morphology. The test results demonstrate that the roots tension with acute angle or right angle to the landslide surface and the roots shear stiffness with obtuse angle can improve the performance of slope’s anti-slide. Four kinds of plants can improve the stability coefficient of shallow soil. As for the slope protection effect, herbage is superior to shrub. In general, grass-shrub mixed community is the ideal system for slope protection.

Juan Wan; Henglin Xiao; Jun He; Lihua Li

2013-01-01

225

Hydrologic design for riprap on embankment slopes  

International Nuclear Information System (INIS)

[en] 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

1988-01-01

226

Eastern slopes grizzly bear project : project update  

Energy Technology Data Exchange (ETDEWEB)

This report updates a study to examine the cumulative effects of human activities on the grizzly bears in the central Canadian Rockies. The project was initiated in 1994 to acquire accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of the study is used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers monitored 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers worked with representatives from Husky Oil and Rigel Energy on the development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over eight years indicates that the grizzly bears have few and infrequent offspring. Using the information gathered thus far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears suffer from high mortality, and the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The research concluded in November 2001 provides sufficient information to accurately asses the status of the grizzly bear population and habitat. The data will be analyzed and integrated in 2002 into models that reflect the variables affecting grizzly bears and a final report will be published.

NONE

2002-01-01

227

Prótese do tornozelo híbrida em um caso de necrose avascular pós-traumática do tálus/ Hybrid ankle prosthesis in a case of post-traumatic avascular necrosis of the talus  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese As fraturas do astrágalo originam frequentemente artrose pós-traumática tardia. Nestes casos, a utilização de próteses do tornozelo não cimentadas de última geração tem sido evitada pela presença de necrose avascular. Relatamos o caso de um paciente com 65 anos que se apresenta quatro anos após uma fratura do colo do astrágalo. Apresentava uma artrose do tornozelo dolorosa (escala AOFAS do retropé e tornozelo 19) e necrose avascular com colapso de toda a cú (more) pula astragalina. Dada a extensão da necrose, foi decidido cimentar o componente protésico astragalino. Um ano após a cirurgia, o paciente apresenta bom resultado clínico e radiológico (escala AOFAS do retropé e tornozelo 87) e está satisfeito com o procedimento. Não temos conhecimento de nenhum relato semelhante na literatura. Abstract in english Talus fractures often lead to late post-traumatic arthrosis. In such cases, the use of latest generation, cementless prostheses has been hindered by the presence of avascular necrosis. We report the case of a 65-year-old patient who presented four years after a talus neck fracture. He had painful ankle arthrosis (AOFAS ankle-hindfoot score 19) and avascular necrosis, with collapse of the entire talar dome. Given the extent of the necrosis, it was decided to cement the tal (more) us prosthetic component. One year after the surgery, the patient shows good clinical and radiological results (AOFAS ankle-hindfoot score 87) and is satisfied with the procedure. We are not aware of any similar reports in the literature.

Sousa, Ricardo Jorge Gomes de; Pinto, Ricardo Pedro Ferreira Rodrigues; Massada, Marta Maria Teixeira de Oliveira; Pereira, Manuel Alexandre Negrais Pinho Gonçalves; Geada, José Muras; Costa, Isabel Maria Gonçalves

2011-01-01

228

Oxygen uptake efficiency slope, aerobic fitness, and V(E)-VCO2 slope in heart failure.  

UK PubMed Central (United Kingdom)

PURPOSE: The oxygen uptake efficiency slope (OUES) is a promising submaximal index of exercise capacity, but its relationships to other indices characterizing physical fitness and ventilatory efficiency have not been widely investigated in heart failure. METHODS: Sixty-three male patients with stable chronic heart failure performed a symptom-limited maximal exercise test on a cycle ergometer. Nineteen of them performed two exercise tests, 6 months apart. The peak oxygen uptake (VO2peak), ventilatory anaerobic threshold (VAT), OUES using all data (OUES(100)) or only the data up to the point where the RER was 1 (OUE(SRER1)), and V(E)-VCO2 slope were determined. RESULTS: OUES(100), OUE(SRER1), and VAT were significantly correlated with measured VO2peak (r = 0.883, r = 0.814, and r = 0.877, respectively). The Bland-Altman limits of agreement between measured VO2peak and the values predicted by calculation from OUES(100), OUE(SRER1), and VAT were ±0.46, ±0.57, and ±0.48 L·min(-1), respectively. The variation in OUE(SRER1) between the first and second tests in the 19 patients was significantly related to the variation in VO2peak but not to the variation in the V(E)-VCO2 slope. CONCLUSIONS: To predict VO2peak in patients with chronic heart failure, the index OUE(SRER1) is not better than the VAT. This, however, does not question the theoretical interest of its calculation because it may provide additional information on the oxygen uptake limitation steps.

Antoine-Jonville S; Pichon A; Vazir A; Polkey MI; Dayer MJ

2012-03-01

229

Factors associated with injuries occurred on slope intersections and in snow parks compared to on-slope injuries.  

UK PubMed Central (United Kingdom)

In alpine winter sports, external risk factors as snow and weather conditions as well as slope characteristics (width, steepness, slope intersections, and snow parks) should be considered when investigating potential risk factors. Therefore, ski patrol injury reports were used to compare factors associated with injuries occurred on slope intersections and in snow parks compared to on-slope injuries. Multivariate regression analysis revealed that in comparison to injuries occurring on ski slopes, collisions with other persons (OR: 2.1, 95% CI: 1.3-3.4) and arm injuries (OR: 2.1, 95% CI: 1.3-3.5) were more likely associated with injuries occurring on slope intersections while male gender (OR: 3.5, 95% CI: 2.1-5.7), younger age (OR: 1.1, 95% CI: 1.0-1.1), slushy/soft snow conditions (OR: 1.9, 95% CI: 1.1-3.3), knee injuries (OR: 0.4, 95% CI: 0.2-0.8) and back injuries (OR: 5.5, 95% CI: 3.0-10.2) were more likely associated with injuries which occurred in snow parks. In conclusion, injuries on slope intersections and in snow parks differ in some factors from injuries sustained on ski slopes.

Ruedl G; Kopp M; Sommersacher R; Woldrich T; Burtscher M

2013-01-01

230

Is there a distinct continental slope fauna in the Antarctic?  

Science.gov (United States)

The Antarctic continental slope spans the depths from the shelf break (usually between 500 and 1000 m) to ˜3000 m, is very steep, overlain by 'warm' (2-2.5 °C) Circumpolar Deep Water (CDW), and life there is poorly studied. This study investigates whether life on Antarctica's continental slope is essentially an extension of the shelf or the abyssal fauna, a transition zone between these or clearly distinct in its own right. Using data from several cruises to the Weddell Sea and Scotia Sea, including the ANDEEP (ANtarctic benthic DEEP-sea biodiversity, colonisation history and recent community patterns) I-III, BIOPEARL (BIOdiversity, Phylogeny, Evolution and Adaptive Radiation of Life in Antarctica) 1 and EASIZ (Ecology of the Antarctic Sea Ice Zone) II cruises as well as current databases (SOMBASE, SCAR-MarBIN), four different taxa were selected (i.e. cheilostome bryozoans, isopod and ostracod crustaceans and echinoid echinoderms) and two areas, the Weddell Sea and the Scotia Sea, to examine faunal composition, richness and affinities. The answer has important ramifications to the link between physical oceanography and ecology, and the potential of the slope to act as a refuge and resupply zone to the shelf during glaciations. Benthic samples were collected using Agassiz trawl, epibenthic sledge and Rauschert sled. By bathymetric definition, these data suggest that despite eurybathy in some of the groups examined and apparent similarity of physical conditions in the Antarctic, the shelf, slope and abyssal faunas were clearly separated in the Weddell Sea. However, no such separation of faunas was apparent in the Scotia Sea (except in echinoids). Using a geomorphological definition of the slope, shelf-slope-abyss similarity only changed significantly in the bryozoans. Our results did not support the presence of a homogenous and unique Antarctic slope fauna despite a high number of species being restricted to the slope. However, it remains the case that there may be a unique Antarctic slope fauna, but the paucity of our samples could not demonstrate this in the Scotia Sea. It is very likely that various ecological and evolutionary factors (such as topography, water-mass and sediment characteristics, input of particulate organic carbon (POC) and glaciological history) drive slope distinctness. Isopods showed greatest species richness at slope depths, whereas bryozoans and ostracods were more speciose at shelf depths; however, significance varied across Weddell Sea and Scotia Sea and depending on bathymetric vs. geomorphological definitions. Whilst the slope may harbour some source populations for localised shelf recolonisation, the absence of many shelf species, genera and even families (in a poorly dispersing taxon) from the continental slope indicate that it was not a universal refuge for Antarctic shelf fauna.

Kaiser, Stefanie; Griffiths, Huw J.; Barnes, David K. A.; Brandão, Simone N.; Brandt, Angelika; O'Brien, Philip E.

2011-02-01

231

Revegetation system on steep rocky slopes and implementing method thereof  

UK PubMed Central (United Kingdom)

The invention discloses a revegetation system on steep rocky slopes and an implementing method thereof, which are suitable for surface vegetalization of steep rocky uncover slopes with the gradient of 60 degrees above. A slope drainage system is arranged in the system to prevent the vegetalization layer from being flushed by rainwater and reduce water loss and soil erosion a mix-sprayed vegetalization layer plastic-covered with iron wire corrugated meshes and consisting of continuous fiber is arranged on the slopes and has stable structure, rich nutrition and functions of water conservation and ventilation. The casting separator prevents the mix-sprayed vegetalization layer from sliding downwards and a drop irrigation facility is distributed to make sure that the vegetalization layer is moist. After maintenance of mix-sprayed construction on the slopes, the vegetable layer with herbaceous plants and shrubs can be effectively formed, thereby reconstructing the destructed vegetables on the slopes and recovering the natural landscapes on the uncover slopes.

ZHENFENG CHEN; DONGQIAO LI; ANCHENG QIN; WENFEI SHI; GONGTIAN WANG; MENGTAO ZHANG

232

The relevance of the slope for concentration-effect relations  

Energy Technology Data Exchange (ETDEWEB)

Risk analysis is mostly based on a comparison of one value for the exposure to a chemical (PEC) and one value for the sensitivity of biota (NEC). This method enables the determination of an effect to be expected, but it is not possible to quantify the magnitude of that effect. Moreover, it is impossible to estimate the effect of a combination of chemicals. Therefore, it is necessary to use a mathematical function to describe the relation between a concentration and the subsequent effect. These relations are typically based on a log normal or log logistic distribution of the sensitivity of individuals of a species. This distribution is characterized by the median sensitivity (EC{sub 50}) and the variation between the sensitivity of individuals (being a measure for the slope of the relation). Presently the attention is focused on the median, while the slope might be even more important. Relevant exposure concentrations are typically in the range which are found in the left tail of the sensitivity distribution. In this study the slope was determined for 250 chemical-species combinations. The data were derived from original experiments and from literature. The slope is highly dependent on the exposure time; the shorter the exposure time the steeper the slope. If data for a standard exposure time [96 hours] are considered, the total variation in slope can partly be explained by the groups of organisms and chemicals. The slope for heavy metals tends to be less steep as compared to the slope of narcotic organic compounds. The slope for fish and molluscs is steeper than for crustaceans. The results of this study are presently applied in a number of risk analysis studies.

Schobben, H.P.M.; Smit, M.; Schobben, J.H.M.; Hendriks, A.J. [TNO, Den Helder (Netherlands). Lab. for Applied Marine Research

1995-12-31

233

Geotechnical characteristics and slope stability in the Gulf of Cadiz  

Science.gov (United States)

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.

Lee, H.; Baraza, J.

1999-01-01

234

Development of a new generation of optical slope measuring profiler  

Energy Technology Data Exchange (ETDEWEB)

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.

Yashchuk, Valeriy V.; Takacs, Peter Z.; McKinney, Wayne R.; Assoufid, Lahsen

2010-07-09

235

Simulating the seismic behaviour of soil slopes and embankments  

DEFF Research Database (Denmark)

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 the obtained results. The investigation conclude to a realistic procedure for seismic slope stability assessment based on the application of two simple methods taking into account the impact of the most important factors involved.

Zania, Varvara; Tsompanakis, Yiannis

2010-01-01

236

Photogrammetry and altimetry: Part C: frequency distributions of lunar slopes  

Science.gov (United States)

The metric and panoramic cameras aboard the Apollo 16 spacecraft provided photographs on which photogrammetric techniques may be used to obtain precise measurements of horizontal distances and elevations. These measurements of horizontal distances and elevations. These measurements may in turn be used to obtain slope-frequency distributions of lunar surfaces at various slope lengths and for various types of terrain and geologic map units (ref. 30-4). Bistatic radar and photoclinometric methods have also been used to obtain slope-frequency distributions of lunar surfaces. The problem arises as to how well these varied methods correlate with one another (ref. 30-5).

Wu, Sherman S. C.; Moore, H. J.

1972-01-01

237

Performance of the APS optical slope measuring system  

Science.gov (United States)

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.

Qian, Jun; Sullivan, Joe; Erdmann, Mark; Khounsary, Ali; Assoufid, Lahsen

2013-05-01

238

Influence of Rainfall Patterns on the Instability of Slopes  

Directory of Open Access Journals (Sweden)

Full Text Available The assessment of rainstorm-induced shallow landslides is still a research topic of wide concern for scientists and engineers. This paper examined the effect of rainfall intensity distribution on shallow landslides. Four synthetic rainfall distributions comprising uniformed, delayed, centralized, and advanced, were selected to examine the effect of rainstorm patterns on slope failure. The infiltration was modeled using Green-Ampt equation, while an infinite slope was selected to model the shallow landslide. Monte Carlo Simulation was applied to analyze the failure probability of the slopes. Two landslide cases were selected to examine the proposed model. The results indicated that among the four representative rainstorm patterns, the advanced rainfall pattern caused worst slope stability. The advanced rainfall pattern resulted in the shortest rainfall duration threshold for landslide occurrence, followed by the central, uniform, and then delayed rainfall pattern. The probabilistic analysis method was suitable to estimate the time of failure for the evaluated landslide cases.

Muntohar A.S.; Ikhsan J.; Liao H.J.

2013-01-01

239

Fast measurement of binding kinetics with dual slope SPR microchips.  

UK PubMed Central (United Kingdom)

We demonstrate a new dual slope SPR technique that is ten-fold faster than the conventional step-response method. The new scheme utilizes rapid slope-based measurements followed by rapid reset, and it separates association and dissociation half reaction measurements at two separate sites inside a dual-chamber PDMS microfluidic chip. For a model CAII-ABS test system, the association and dissociation slopes were measured in 30 seconds compared to 5 minutes for step-response. The values of k(a) and k(d) calculated from the slope method are 3.66 ± 0.19 × 10(3) M(-1) s(-1) and 4.83 ± 0.17 × 10(-2) s(-1), respectively, matching well with step-response values while facilitating ~10 to 15 fold faster detection and quantification.

Ghosh T; Mastrangelo CH

2012-05-01

240

The stability of grounding lines on retrograde slopes  

Directory of Open Access Journals (Sweden)

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 marine 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 a retrograde slope, must be inherently unstable.

G. H. Gudmundsson; J. Krug; G. Durand; L. Favier; O. Gagliardini

2012-01-01

 
 
 
 
241

POTENTIALLY UNSTABLE SLOPE ABOVE ORE PROCESSING PLANT IN THE  

Directory of Open Access Journals (Sweden)

Full Text Available The complex engineering investigation, in the nearest surroun-dig of the conditionally stable high slope, close to ore processing facilities in the dolomite quarry »O?ura« near Lepoglava (North Croatia), was carried out. Studying the tectonic features of the rock mass, discontinuities referent to the slope stability, was found out. Rock fragment size was measured and data processed using statistical design. According to rock fragment mean values, velocity of the longitudinal seismic waves was predicted. This values was compared with velocities of the longitudinal seismic waves, determined using gcophisical refraction seismic method. Physical and mechanical properties of the dolomite rock mass, considering longitudinal and transversal seismic wave velocities, and »RMR«-classification was assesed. All the results indicate, that the slope above the ore processing facilities should be consider as conditionally stable, with real probability to get unstable under the vibrations caused by blasting, during the exploitation in the field, close behind the investigated slope.

Karlo Braun; Željko Mlinar; Ivan Baturi?

1993-01-01

242

Criteria for Limit Equilibrium Slope Stability Program Package.  

Science.gov (United States)

The criteria for a general limit equilibrium slope stability computer program package to define the desired capabilities and features are presented. The criteria cover the screening requirements for the evaluation of the various methods of analysis, and e...

1985-01-01

243

Stability Analysis and Stability Chart for Unsaturated Residual Soil Slope  

Directory of Open Access Journals (Sweden)

Full Text Available In tropical residual soils most hill slope failures are caused by rainfall. It is therefore important to consider dynamic hydrological conditions when attempting to analyze the stability of residual soil slopes. This paper describes a coupled hydrology/stability model that has been developed to overcome the limitations of the standard method of analysis used to investigate stability of tropical soil slopes. A computational hydrology ? limit equilibrium stability analysis model is outlined and examples are provided of the model output capabilities in terms of design charts. Although nowadays most realistic problem should be analyzed by computer and stability charts are mainly used to analyze simple slopes, they can be useful for preliminary analysis and enable the designer to quickly assess the sensitivity of a problem to changes in different input parameters.

Bugang B.K. Haut; Faisal H.  Ali; R. S.K. Rajoo

2006-01-01

244

High Resolution Sensing Techniques for Slope Stability Studies.  

Science.gov (United States)

The National Bureau of Standards (NBS), in conjunction with the U.S. Geological Survey (USGS), conducted a four-phase evaluation of high resolution remote sensing techniques for application to problems of determining slope stability. The first two phases,...

R. L. Jesch R. B . Johnson D. R. Belsher A. D. Yaghjian M. C. Steppe

1979-01-01

245

The stability of grounding lines on retrograde slopes  

Directory of Open Access Journals (Sweden)

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.

G. H. Gudmundsson; J. Krug; G. Durand; L. Favier; O. Gagliardini

2012-01-01

246

Method for planting evergreen vegetation slope highway in south China  

UK PubMed Central (United Kingdom)

The invention provides a south China highway slope evergreen vegetation planting method. The reasonable plant allocation scheme is adopted. The grass seed ands the shrub species are used for the preparation of seed spray liquid spraying to the levelled slop surface suitable for greening. According to the seed spray liquid formulation, per square meter slope is in the use of 40 to 55g mixed grass and shrub seeds, 100 to 150g pulp, 3 to 8g polyvinyl alcohol or polyacrylamide type adhesive, 3 to 8g polyethylene lactam, polyacrylamide or polyacrylate type water retention agent, 50 to 100g NPK compound fertilizer and 4 liter water. The invention is suitable for the establishment of evergreen vegetation in south China highway slope with natural succession. Ultimately the purpose of soil erosion prevention, slope stability, landscaping and ecological balance protection can be achieved.

DINGQIANG LI; MUNING ZHUO; YUJI ZHENG

247

Slope analysis for elastic nucleon-nucleon scattering  

CERN Multimedia

The diffraction slope parameter is investigated for elastic proton-proton and proton-antiproton scattering based on the all available experimental data at low and intermediate momentum transfer values. Energy dependence of the elastic diffraction slopes is approximated by various analytic functions. The expanded "standard" logarithmic approximations with minimum number of free parameters allow to describe experimental slopes in all available energy range reasonably. The estimations of asymptotic shrinkage parameter $\\alpha'_{\\cal{P}}$ were obtained for various $|t|$ domains based on the all available experimental data. Various approximations differ from each other both in the low energy and very high energy domains. Predictions for diffraction slope parameter are obtained for elastic proton-proton scattering at NICA, RHIC and LHC energies, for proton-antiproton elastic reaction in FAIR energy domain for various approximation functions.

Okorokov, V A

2009-01-01

248

User Information Manual Dynamic Slope Stability Displacement Program 'DISP.'  

Science.gov (United States)

The DISP (Dynamic Slope Stability Displacement Program) is a specific purpose computer program to calculate the time-displacement response of any wedge in a slide mass subjected to a prescribed earthquake loading. The equation of motion implemented in the...

A. K. Chugh

1980-01-01

249

Submarine landslides along the eastern Mediterranean Israeli continental slope  

Science.gov (United States)

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.

Reuven, Einav; Katz, Oded; Aharonov, Einat

2013-04-01

250

Slopes of trigonal fibred surfaces and of higher dimensional fibrations  

CERN Multimedia

We give lower bounds for the slope of higher dimensional fibrations over curves under conditions of GIT-semistability of the fibres, using a generalization of a method of Cornalba and Harris. With the same method we establish a sharp lower bound for the slope of trigonal fibrations of even genus and general Maroni invariant; in particular this result proves a conjecture due to Harris and Stankova-Frenkel.

Barja, Miguel A

2008-01-01

251

Pros and cons of exporting Alaskan North Slope oil  

Energy Technology Data Exchange (ETDEWEB)

US laws restrict the export of oil produced from Alaska's North Slope fields. Whether some of that oil should now be exported is a subject of debate. The controversy involves complex political and economic matters which affect the oil and maritime industries, government revenues, national security, and international relations. In this report, GAO presents the major perceived advantages and disadvantages of exporting Alaskan North Slope oil.

1983-09-26

252

Computer-aided Deflection and Slope Analyses of Beams  

Directory of Open Access Journals (Sweden)

Full Text Available An analyses program of deflection and slope of beams is presented. Mechanical, mathematical and computer methods, techniques and models are included in the program. We can quickly and accurately obtain the deflections and slopes of cantilever and simply supported beams from this program. Moreover, the program can be executed in PC machine, also the design algorithm in this study can be performed in other computer systems. Two critical examples are given to illustrate this program.

Tzong-Mou Wu

2006-01-01

253

On the slope of the elastic differential cross sections  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Making use of a model-independent analytical fit for the elastic hadron-hadron amplitude, recently developed, we investigate the slope of the proton-proton and antiproton-proton differential cross sections, as a function of the energy and the momentum transfer. We show that the predictions for these quantities are in agreement with the experimental data available and discuss the effect of the slope position as function of the momentum transfer.

Campos, S. D.; Menon, M. J.; Montanha, J.

2007-03-01

254

Slope-mass-correlation in diffractive dissociation reactions  

Energy Technology Data Exchange (ETDEWEB)

A set of new results of new Three Component Deck Model for Diffractive Dissociation Reactions is presented. These new results are confronted with recently published ones to obtain a general view 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) and slope-mass-partial wave correlations.

Antunes, A.C.B.; Santoro, A.F.S.; Souza, M.H.G.

1984-12-01

255

Analysis of slope stabilization by soil bioengineering method  

Science.gov (United States)

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.

Switala, Barbara Maria; Wu, Wei

2013-04-01

256

Problems of definitive slopes mining at Doly Nastup Tusimice  

International Nuclear Information System (INIS)

[en] 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)

2007-01-01

257

76 FR 56789 - Call for Nominations: North Slope Science Initiative, Science Technical Advisory Panel, Alaska  

Science.gov (United States)

...Land Management [AK-910-09-1739-NSSI] Call for Nominations: North Slope Science...programs of North Slope Science Initiative (NSSI) member organizations on the North Slope...that scientific products generated through NSSI activities are of the highest...

2011-09-14

258

Soil properties in high-elevation ski slopes  

Science.gov (United States)

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

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

2010-05-01

259

The influence of preferential flow on slope stability  

Science.gov (United States)

Slope failures triggered by heavy rainfall are common geological disasters around the world, because rainfall caused pore-pressure increase will reduce the soil shear strength and influence the slope stability. Physically-based subsurface hydrological models are frequently integrated with slope stability analysis methods to evaluate which areas are susceptible for landslides. In structured soil, preferential flow can change the pattern of the infiltration process, resulting in more rapid and deeper water movement. For highly-heterogeneous slopes, the influence of preferential flow on the distribution of pore water pressure and slope stability has not been studied thoroughly yet. In this study, the COMSOL Multiphysics finite element software package is used to model the hydrological and soil mechanical processes. A two-dimensional hydro-mechanical model framework composed of a subsurface flow module and a slope stability analysis module was built to evaluate the influence of preferential flow on subsurface flow and consequent slope stability. The subsurface flow module consists of a dual-permeability model, which can be used to quantify the influence of preferential flow on distribution and timing of the pressure head in a slope. The dual-permeability model divides the soil into matrix domain and preferential flow domain, and the water flow is described by two coupled Richard's equations. The slope stability analysis module is composed of an elastic solid mechanics model and a local factor of safety algorithm. The total principle stress distribution is calculated by a solid mechanics module for plane-strain elastic analyses. The local factor of safety is defined as the ratio of the Coulomb stress at the current state of stress to the Coulomb stress of the potential failure state under the Mohr-Coulomb criterion. In this study the focus will be on the temporal and spatial distribution of the local factor of safety. Eventually, the influence of preferential flow on slope stability can be evaluated by comparing the results of the single-permeability model and the dual-permeability model.

Shao, Wei; Bogaard, Thom A.; Bakker, Mark

2013-04-01

260

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 costs and throws the other hand, the stability conditions in the safe walls of the mine life will provide essential and seems obvious. Therefore, in this study to determine the optimal slope angle of overall and bench of west wall of the Chadormalu ore iron mine, has been trying, first, done field studies on the discontinuity of western wall, engineering classification and geomechanical properties of rock masses of wall, then assess the amount of optimal slope angle using empirical method. Finally, in order to ensure stability and accuracy of the wall slope angle based on the obtained (empirical method) tries to analysis is amount of Factor of Safety (FOS), displacements and mean stress condition atwalls calculated from drilling use Phase2D powerful software.

Mahdi Rasouli Maleki; Mohammad Mahyar; Kambiz Meshkabadi

2011-01-01

 
 
 
 
261

Eastern Olympus Mons Basal Scarp: Potential for active slope mobilization?  

Science.gov (United States)

The volcanic edifice of Olympus Mons is surrounded by presumed mass-movement landforms known as the aureole deposits. It has been suggested that the aureole deposits are the result of a catastrophic failure of the volcanic edifice. Tantalizingly, a topographic examination of the Eastern flank of Olympus Mons suggests that a large failure may have been captured. The flank exhibits a ~ 80 km near-continuous extensional fracture, bounded on either side by radial tear faults, that cut both the scarp face, and the more recent lava flows that have modified the basal scarp. Observed along fault offsets are on the order of 100 m. A compressional toe, parallel and downslope to the extensional fracture, may be linked and the result of downslope movement of the flank. If so, then a significant portion of the outer edge of the Eastern basal scarp may define a coherent zone of slope instability, or failure. Using digital elevation models derived from HRSC data, several transects along the basal scarp slope face are analyzed to better understand and quantify the stability of each section of the eastern slope, and examine potential failure conditions and mechanisms. Slope stability analysis is used to determine the likelihood of the Eastern basal scarp experiencing a catastrophic failure along the entire fault trace. This result may indicate an active failure process that can lead to an aureole type deposit. If this failure were to occur, a simple case of a curvilinear slip surface connecting the up-slope extensional and down-slope compressional fault traces produces an estimate for the potential mobile landslide volume on the order of 1000 cubic km, or ~ 5-10% of the volume previously estimated for the aureole lobe off of the east flank of Olympus Mons. Preliminary results from topography show that numerous smaller-scale localized slope failures that are emplaced upon young lava flows have occurred along this section of the basal scarp, suggesting significant instability and a strong potential for failure.

Weller, M. B.; McGovern, P. J.; Fournier, T.; Katz, O.; Morgan, J. K.

2011-12-01

262

Estimating Coastal Slopes Vulnerability in Dakar Peninsula, West Senegal  

Science.gov (United States)

Dakar Peninsula, where most of the economically active places in Senegal are concentrated, has been repeatedly subjected to rockfalls and coastal erosion on the stretch of coastline between Pointe des Abattoirs and Pointe de Dakar. Coastal scientists, engineers and political leaders are increasingly being called upon to assess the physical and socio-economic impacts of such slope degradation, and hence explore appropriate response strategies. The objective of this terrain hazard mapping study was to collect information to enable the prevention and control of slope failure and slope degradation to be made on a rational basis. The area to be investigated was defined and sub-areas were further subdivided into 12 individual sections and assigned hazard and risk categories or levels derived from the field data.The present study evaluated the risk of slope failure within a conventional probabilistic framework based on slope outcrop inventory and structural discontinuities measurements, geomorphological mapping combined with air photograph interpretation, review of pre-existing geotechnical data as well as the sampling of rock specimen for laboratory testing and analysis. Detailed sea level rise analysis reported elsewhere leads to the conclusion that the background geology of the area should be looked as the cause to the several coastal hazards, among which slope instability poses the most important urban management problems in Dakar. From the results of the study it was possible to infer that local rockfalls and degradation of rock slopes are closely linked to the geological setting of the area, notably local rock type and structure, local hydrogeological conditions, local topography and geomorphological processes, as well as a poor city planning and overpopulation. The results also showed that geomorphological mapping can provide an effective tool to the engineering geologist in anticipating the slope failure processes which may otherwise go unnoticed. Eventually the probabilistic method has been found to work consistently for this case study and therefore suggests that the orientation and distribution of structural discontinuities play a key role for assessing the risk of slope failure with acceptable degree of accuracy.

Diop, S.

2004-12-01

263

Slope stability probability classification, Waikato Coal Measures, New Zealand  

Energy Technology Data Exchange (ETDEWEB)

Ferm classified lithological units have been identified and described in the Waikato Coal Measures in open pits in the Waikato coal region. These lithological units have been classified geotechnically by mechanical tests and discontinuity measurements. Using these measurements slope stability probability classifications (SSPC) have been quantified based on an adaptation of Hack's [Slope Stability Probability Classification, ITC Delft Publication, Enschede, Netherlands, vol. 43, 1998, 273 pp.] SSPC system, which places less influence on rock quality designation and unconfined compressive strength than previous slope/rock mass rating systems. The Hack weathering susceptibility rating has been modified by using chemical index of alteration values determined from XRF major element analyses. Slaking is an important parameter in slope stability in the Waikato Coal Measures lithologies and hence, a non-subjective method of assessing slaking in relation to the chemical index of alteration has been introduced. Another major component of this adapted SSPC system is the inclusion of rock moisture content effects on slope stability. The main modifications of Hack's SSPC system are the introduction of rock intact strength derived from the modified Mohr-Coulomb failure criterion, which has been adapted for varying moisture content, weathering state and confining pressure. It is suggested that the subjectivity in assessing intact rock strength within broad bands in the initial SSPC system is a major weakness of the initial system. Initial results indicate a close relationship between rock mass strength values, calculated from rock mass friction angles and rock mass cohesion values derived from two established rock mass classification methods (modified Hoek-Brown failure criteria and MRMR) and the adapted SSPC system. The advantage of the modified SSPC system is that slope stability probabilities based on discontinuity-independent and discontinuity-dependent data and a maximum slope height are predicted. The modified SSPC system may be useful in predicting initial optimum pit slope designs in proposed greenfield mine sites. XRF major element and chemical index of alteration (CIA) results obtained for lithologies in the Waikato coal region may be a useful mine management tool to quantify stratigraphic thickness and palaeoweathering from wash drill cuttings. This paper explains the systematic approach of using the adapted SSPC system to classify slope stability in the Waikato open pit coal mines.

Lindsay, P.; Gillard, G.R.; Moore, T.A. [CRL Energy, PO Box 29-415, Christchurch (New Zealand); Campbell, R.N.; Fergusson, D.A. [Solid Energy North, Private Bag 502, Huntly (New Zealand)

2001-01-01

264

Direct Strain and Slope and Slope Measurement Using 2D DSPSI  

International Nuclear Information System (INIS)

[en] 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)

2011-01-01

265

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

UK PubMed Central (United Kingdom)

"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.

Boer TA

2003-01-01

266

Reflection of a long wave from an underwater slope  

Science.gov (United States)

Reflection of long sea waves from an underwater slope described by a power law is studied within the shallow water theory. The slope is connected with the flat bottom. This model allows us to estimate the roles of a pointwise reflection from the inflection point of the bottom profile and distributed reflection at the underwater slope. The case of the underwater slope described by the so-called nonreflecting beach ( h( x) ˜ x 4/3, where h is the depth of the basin and x is the coordinate) when the wave is reflected only from the inflection point (pointwise reflection) is specially considered. The reflection and transmission coefficients over the bottom topography were calculated, and it was shown that the sum of the squared absolute values of these values differs from unity for all profiles except the nonreflecting one. This difference is related to the distributed re-reflections (resonances) over the underwater slope that lead to the deviations in the wave height from the known Green's law.

Didenkulova, I. I.; Pelinovsky, E. N.

2011-08-01

267

Novel measurement technique of the tibial slope on conventional MRI.  

UK PubMed Central (United Kingdom)

UNLABELLED: The posterior inclination of the tibial plateau, which is referred to as posterior tibial slope, is determined routinely on lateral radiographs. However, radiographically, it is not always possible to reliably recognize the lateral plateau, making a separate assessment of the medial and lateral plateaus difficult. We propose a technique to measure the plateaus separately by defining a tibial longitudinal axis on a conventional MRI. The medial plateau posterior tibial slope obtained from radiographs was compared with MR images in 100 consecutive patients with knee pain when ligament or meniscal injury was assumed. The posterior tibial slope on MRI correlated with those on radiographs. The mean posterior tibial slope was 3.4 degrees smaller on MRI compared with radiographs (4.8 degrees +/- 2.4 degrees versus 8.2 degrees +/- 2.8 degrees , respectively). The reproducibility was slightly better on radiographs than MRI (+/- 0.9 degrees versus +/- 1.4 degrees ). Twenty-one of the 100 cases had more than a 5 degrees difference (range, -8.7 degrees to 8.9 degrees ) between the medial and lateral plateaus. The proposed technique allows measurement of the posterior tibial slope of the medial and lateral plateaus on a standard knee MRI. By using this novel measurement technique, a reliable assessment of the medial and lateral tibial plateaus is possible. LEVEL OF EVIDENCE: Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Hudek R; Schmutz S; Regenfelder F; Fuchs B; Koch PP

2009-08-01

268

Infinite slope stability under steady unsaturated seepage conditions  

Science.gov (United States)

[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.

Lu, N.; Godt, J.

2008-01-01

269

A preliminary pit slope stability study Kvanefjeld, South Greenland  

International Nuclear Information System (INIS)

[en] 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)

1983-01-01

270

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 potentially unstable and can lead to planar failure. The Markland test carried out for wedge failure indicates that the intersection of the discontinuities does not fall within the critical zone hence there cannot be any wedge failure of the slope within the level 241 - 258 m. The presence of discontinuities that plot within the toppling critical zone indicates that there is potential toppling failure on the slope at the 276 - 286 m level. In addition, the toppling failure test shows the absence of discontinuities that plot within the toppling critical zone and this indicates the absence of poten-tial toppling failure of the slope at the 308 - 312 m level. The result of the study will be useful to the man-agement of the Itakpe iron ore mine in having a proper understanding of the failure mechanism of the slopes.

Rasheed A. Adebimpe; Jide Muili Akande; Chinwuba Arum

2011-01-01

271

Slope Error Measurement Tool for Solar Parabolic Trough Collectors: Preprint  

Energy Technology Data Exchange (ETDEWEB)

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.

Stynes, J. K.; Ihas, B.

2012-04-01

272

Development of a new generation of optical slope measuring profiler  

Energy Technology Data Exchange (ETDEWEB)

A collaboration, including all DOE synchrotron labs, industrial vendors of x-ray optics, and with active participation of the HBZ-BESSY-II optics group has been established to work together on a new slope measuring profiler -- the optical slope measuring system (OSMS). The slope measurement accuracy of the instrument is expected to be<50 nrad for the current and future metrology of x-ray optics for the next generation of light sources. The goals were to solidify a design that meets the needs of mirror specifications and also be affordable; and to create a common specification for fabrication of a multi-functional translation/scanning (MFTS) system for the OSMS. This was accomplished by two collaborative meetings at the ALS (March 26, 2010) and at the APS (May 6, 2010).

Yashchuk, Valeriy V.; Takacs, Peter Z.; McKinney, Wayne R.; Assoufid, Lahsen; Siewert, Frank; Zeschke, Thomas

2010-09-16

273

Predicting moisture problems in low-slope roofing  

Energy Technology Data Exchange (ETDEWEB)

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.

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

274

Instrumentation for slope stability -- Experience from an urban area  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the monitoring of several existing landslides in an urban area near Wollongong in the state of New South Wales, Australia. A brief overview of topography and geology is given and reference is made to the types of slope movement, processes and causal factors. Often the slope movements are extremely slow and imperceptible to the eye, and catastrophic failures are quite infrequent. However, cumulative movements at these slower rates do, over time, cause considerable distress to structures and disrupt residential areas and transport routes. Inclinometers and piezometers have been installed at a number of locations and monitoring of these has been very useful. The performance of instrumentation at different sites is discussed in relation to the monitoring of slope movements and pore pressures. Interval rates of inclinometer shear displacement have been compared with various periods of cumulative rainfall to assess the relationships.

Flentje, P.; Chowdhury, R.

1999-07-01

275

Modeling thermal asymmetries in double slope solar stills  

Energy Technology Data Exchange (ETDEWEB)

Solar distillation literature reports a generalized use of stills with single and double slope condensing covers, where modeling equations describe a solution approach that considers the condenser as a single element. The solution for a double slope still analysis is generally forced to the case of one with a single flat condensing cover. This paper proposes a new lumped parameters mathematical model to study the asymmetries that arise in the temperature and distillate yield in double slope solar stills. The condenser is studied as a two-element system and non-simplified equations for heat transfer and optical transmission characteristics are used. The model is tested for the case with the strongest thermal differences and validated with experimental data. Overall results show a good correlation between predictions and experimentation. (author)

Rubio, E.; Porta Gandara, M.A. [CIBNOR, La Paz (Mexico); Fernandez, J.L. [UNAM, Mexico (Mexico). Inst. de Ingenieria

2004-05-01

276

A New Closure to Slice Model for Slope Stability Analysis  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a new closure to slice models for evaluating slopes. The discussion is based on the minimal inter-slice action (MIA) hypothesis, which results in a new slice model without including artificially adjustable parameters. It has been realized that the new slice model predicts the minimum value of the safety factor, while all other slice models available always overestimate the value of the safety factor. Moreover, the gravity moment of each slice is found to be opposite to the overturning moment, which is different from the existing knowledge. In particular, the new slice model overcomes the situation where different assumptions of the inter-slice force function will give different safety factors to the same slope. The related numerical examples indicate that the new slice model can serve as a reliable tool for investigating geotechnical slope stability.

Tianyun Liu; Yunling Duan; Chongbin Zhao

2012-01-01

277

Surface currents and slope selection in crystal growth  

CERN Multimedia

We face the problem to determine the slope dependent current during the epitaxial growth process of a crystal surface. This current is proportional to delta=p(+)-p(-), where p(+/-) are the probabilities for an atom landing on a terrace to attach to the ascending (p(+)) or descending (p(-)) step. If the landing probability is spatially uniform, the current is also proportional to the average (signed) distance traveled by an adatom before incorporation in the growing surface. The phenomenon of slope selection is determined by the vanishing of the asymmetry delta. We apply our results to the case of atoms feeling step edge barriers and downward funnelling, or step edge barriers and steering. In the general case, it is not correct to consider the slope dependent current J as a sum of separate contributions due to different mechanisms.

Politi, P

2006-01-01

278

Wetting Front Advance From a Point Source in Sloping Fields  

Directory of Open Access Journals (Sweden)

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.

Behrouz Mostafazadeh; Sayed-Farhad Mousavi; Mohammad Hossain Sharif-Bayanolhagh

1998-01-01

279

Finite element simulation of retrogressive failure of submarine slopes  

Science.gov (United States)

Many instances of retrogressive landslides, initially triggered by earthquake, sedimentation, gas release, etc., have damaged structures or facilities off- or near-shore. To simulate earthquake-induced, retrogressive submarine slope failures, element removal capabilities of a finite element program, DYNAFLOW, are used to model a soil mass that fails and then flows away, causing upper parts of slope to fail retrogressively due to loss of support. It is explained how an initial failure leads to subsequent failures of a flat or gently sloping seafloor. Effects of a silt layer and gently sloping seafloor on the extension of retrogression in a sand deposit are studied. The extension of failure increases significantly for a gently sloping seafloor with the presence of a silt layer. DYNAFLOW is a state-of-the-art general-purpose finite element analysis program for linear and nonlinear, two- and three-dimensional systems. Coupled porous media analysis is performed by means of an extension of Biot's formulation in the nonlinear regime. A multi-yield constitutive model is used for simulating the behaviour of soil materials. It is a kinematic hardening model based on a simple plasticity theory, and is applicable to both cohesive and cohesionless soils. The yield function is described in the principal stress space by a set of nested conical yield surfaces. A non-associative plastic flow rule is used for the dilatational component of the plastic deformation. Accurate simulation of shear-induced plastic dilation and of hysteretic effects under cyclic loading, together with full coupling between solid and fluid equations, allow capturing the build-up and dissipation of pore water pressures and modelling the gradual softening and hardening of soil materials. This study is a part of COSTA-Canada, a Canadian contribution to the study of continental slope stability.

Azizian, A.; Popescu, R.

2003-04-01

280

Observations of the structure and development of nocturnal slope winds  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the slope flow data at an intermediate stage of analysis. Work is continuing on both the Cobb Mountain and Rattlesnake data. The Unit 19 data will be compared to the less-detailed wind and temperature data from other locations in order to obtain a more general picture of both the slope flow and the resulting drainage flow during the 1980 Geysers field study. In addition, during the summer of 1981 new data are being collected at the Rattlesnake site with an expanded array of instrumentation, including both wind and temperature profiles at site A and a fast-response anemometer for detailed turbulence measurements at site B.

Horst, T.W.; Doran, J.C.

1981-06-01

 
 
 
 
281

Red Beans and Rice: Slope failure experimental modeling  

Science.gov (United States)

In this activity, students replicate the slope failure experiment presented by Densmore et al. (1997) in the journal Science. They are given the original article and the slope failure apparatus (along with all associated materials) and then they need to figure out how to replicate the experiment. Once they have completed an experimental run of sufficient length, they compile and analyze their data and compare it to the article's results. After completing this portion of the lab, the students read the discussion and reply (Aalto et al., 1998; Densmore et al., 1998) and critically evaluate they results of the experiment and its applicability to the real world and landscape evolution.

Hickson, Thomas

282

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.

2009-01-01

283

Intrinsic limits of subthreshold slope in biased bilayer graphene transistor  

Science.gov (United States)

In this work, we investigate the intrinsic limits of subthreshold slope in a dual gated bilayer graphene transistor using a coupled self-consistent Poisson-bandstructure solver. We benchmark the solver by matching the bias dependent band gap results obtained from the solver against published experimental data. We show that the intrinsic bias dependence of the electronic structure and the self-consistent electrostatics limit the subthreshold slope obtained in such a transistor well above the Boltzmann limit of 60 mV/decade at room temperature, but much below the results experimentally shown till date, indicating room for technological improvement of bilayer graphene.

Majumdar, Kausik; Murali, Kota V. R. M.; Bhat, Navakanta; Lin, Yu-Ming

2010-03-01

284

Channel Slopes on Amazon Basin Rivers From the SRTM DEM  

Science.gov (United States)

Changes in surface water storage (S) and discharge (Q) are poorly known globally but are critical for constraining the terrestrial branch of the water cycle. To date, only the SRTM mission provides global measurements of both surface water area and elevation. However, little is known about the instrument performance for collecting delta-S and Q. The Amazon Basin is a particularly appealing target given its sparse gauge density, lack of continuous and reliable slope data that can be used in the estimation of discharge, and complexity of flow hydraulics. We have used SRTM elevation data in conjunction with flow distance to estimate water surface slope for the area 0S-8S, 72W-54W. Using a 3rd order polynomial fit to the distance-elevation data, slope values of the mainstem Amazon range from less than 0.5 cm km-1 downstream of Obidos to 4.10 cm km-1 3000 km upstream of this location. The central Amazon slope ranges from 1.86 cm km-1 to 3.10 cm km-1 from Manaus to the Rio Japura (about 800 km upstream). Local slopes for specific gauge locations were achieved using both a linear fit to the data and the polynomial fit. The slope value at Itapeua, about 430 km upstream of Manaus, was found to be 3.22 cm km-1 using a linear fit, and 2.65 - 2.79 cm km-1 using a 3rd order polynomial fit, for a reach of 24 km. The slope value for Manacapuru, about 90 km upstream of Manaus, was determined to be 3.56 cm km-1 using a linear fit and 1.97 - 2.12 cm km-1 for a reach of 70 km centered on the local gauge. This slope is used in the Manning equation (n = 0.03) with depth values from navigation charts and river width measured from JERS-1 SAR imagery to yield discharge values for Manacapuru of 93,500 m3 sec-1and for Itapeua of 81,900 m3 sec-1. The observed discharge value at the Manacapuru gauge is 96,300 m3 sec-1 over an 11-day average in February for the years 1973-1991. The average observed discharge value for Itapeua is 83,100 m3 sec-1 for the same time period.

Hendricks, G.; Alsdorf, D. E.

2004-12-01

285

The Slope Polynomial and Collinear Points in Permutations  

CERN Document Server

We consider a polynomial -- which we term the ``slope polynomial'' -- that encodes information about slopes of lines defined by a point-set in finite affine planes. When the aforementioned point-set is the graph of a permutation, we show that constancy of the polynomial is equivalent to the permutation being linear. This has immediate consequences for the structure of the 3-uniform hypergraph of collinear triples of the graph of a permutation, an issue that is itself connected with important questions in harmonic analysis and combinatorial number theory.

Cooper, J N

2006-01-01

286

Research on the seasonal snow of the Arctic Slope  

Energy Technology Data Exchange (ETDEWEB)

This project deals with the seasonal snow on Alaska's Arctic Slope. Although it is concentrated on snow of the R{sub 4}D 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.

Benson, C.S.

1991-01-01

287

Research on the seasonal snow of the Arctic Slope  

Energy Technology Data Exchange (ETDEWEB)

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.

Benson, C.S.

1989-01-01

288

Strong runup of long internal wave on a gentle slope  

Science.gov (United States)

We report on velocity measurements during runup of strong internal waves on a gently sloping beach in a laboratory model. Very strong velocities are found when the incoming waves are very long. A maximal speed of 40 percent of the linear internal long wave speed is noted. Surprisingly the measurements agree with observations of comparable events measured in deep water at the shelf slope of Norway. Details of breaking of the waves, runup and induced velocities due to sets of experiments, varying the input wave will be presented.

Sveen, J. K.; Grue, J.

2003-04-01

289

The F1 ledge: density, height and slope  

Directory of Open Access Journals (Sweden)

Full Text Available Diurnal variations of the F1 region ionization at 170 km altitude and the slope ?170 = dN/dh at this height are analyzed for mid-latitude and equatorial stations: Millstone Hill, Ramey, Puerto Madryn and Jicamarca. Both the density N(t) and the slope ?(t)at 170 km show well defined diurnal variations with day-to-day variabilities of less than 10%. The heights of the F1 ledge, hmF1, are spread over ± 20 km and are therefore of limited value for modeling purposes.

B. W. Reinisch; X. Huang

1996-01-01

290

Target and method of vegetation recovery at abandoned mine slope  

UK PubMed Central (United Kingdom)

The main target of ecological environment improvement for abandoned mine is side slope stability control and vegetation recovery. Ever green broad leaf forest, the exotic zonal vegetation in Zhejiang province is the target forest for the improvement of abandoned mine slope. But limited by special site and growth condition, selection of plant for envi- ronment improvement should be similar with nearby ones, thus making the future community stable. Exotic species like Lespedeza thunbergii were recommended for the plantation by seed spray and container seedling plantation.

Liu Bentong; Wang Zhiming

2005-01-01

291

Development of deep-seated gravitational slope deformation on a shale dip-slope: observations from high-quality drillcores  

Science.gov (United States)

The internal structures within a gravitationally deformed slope were observed using high-quality drillcores obtained from a dip slope of a series of shale-dominated sediments. This slope has dimple-like depressions and an overall gentle slope angle, but has no well-defined landslide scarp, suggesting that this area underwent gravitationally deformation but with no separation of the deformed portion from the surrounding area. Three drillcores, to a maximum depth of 96 m, were used during this study, with detailed observations of cut paraffin-impregnated core surfaces used to characterize gravitational deformation in the study area. This logging identified shear zones that consist of disintegrated (brecciated) and pulverized zones that were up to 88 and 19 cm thick, respectively. Disintegrated zone breccias have local jigsaw-fit textures, but other areas contain compositional trails formed by cataclastic flow, and rounded outlines formed by attrition. Pulverized zones underwent increased amounts of shearing, leading to the formation of more rounded fragments and increasing amounts of clayey matrix material, but still containing more than 30% of visible rock fragments. As such, these zones are still classified as breccias in terms of fault rock classification. Planar structures, such as R and Y shears, and P foliations, are not developed in the study area. Shear zones are intermittently located across the slope and have not formed a through-going master sliding zone. Incipient shear zones are present within the slope, including a pair of shear surfaces with a pull apart-like opening, and thin disintegrated or pulverized zones in intact rocks at 3-10 m below the base of the main area of gravitational deformation, suggesting that these shear zones propagate downward in a step-wise manner. This propagation may be related to the redistribution of stress induced by river incision.

Chigira, Masahiro; Hariyama, Takehiro; Yamasaki, Shintaro

2013-04-01

292

Living-establishing disk for slope greening zoology-recovering  

UK PubMed Central (United Kingdom)

The utility model relates to a vegetation disc belonging to processed products of plant residues obtained from constructed wetlands or other plant residues, which is a product particularly adapting to recover and green on-slope vegetation excavated in engineering constructions of roads, railways, water conservation, mine and electric power and the like, which are poor in fertility conditions as soil depletion and the like. The vegetation disc is a hexagonal hollow brick or a block with different shape made of degradable plant residue cellulose, which is formed in a mould by pressing after mixing a certain amount of plant seeds with glue applied to on-slope ecological recovery, and block bodies with different size, shape and specification can be manufactured for vegetation discs by the mould. The vegetation disc has low cost and convenient construction, solves the defect that common cement hollow hexagonal hollow brick is not favorable for vegetation recovery, and overcomes the problem that firmness after using pure soil or other organic base materials as ejection base materials is limited while these organic base materials are favorable for plant growing. The product can meet requirements of fast greening and ecological recovery for slopes, and achieves excellent functions of fixing slope and water and soil conservation.

FUTANG DENG; FUSHANG DENG

293

Nonlinear run-ups of regular waves on sloping structures  

Directory of Open Access Journals (Sweden)

Full Text Available For coastal risk mapping, it is extremely important to accurately predict wave run-ups since they influence overtopping calculations; however, nonlinear run-ups of regular waves on sloping structures are still not accurately modeled. We report the development of a high-order numerical model for regular waves based on the second-order nonlinear Boussinesq equations (BEs) derived by Wei et al. (1995). We calculated 160 cases of wave run-ups of nonlinear regular waves over various slope structures. Laboratory experiments were conducted in a wave flume for regular waves propagating over three plane slopes: tan ? =1/5, 1/4, and 1/3. The numerical results, laboratory observations, as well as previous datasets were in good agreement. We have also proposed an empirical formula of the relative run-up in terms of two parameters: the Iribarren number ? and sloping structures tan ?. The prediction capability of the proposed formula was tested using previous data covering the range ? ? 3 and 1/5 ? tan ? ? 1/2 and found to be acceptable. Our study serves as a stepping stone to investigate run-up predictions for irregular waves and more complex geometries of coastal structures.

T.-W. Hsu; S.-J. Liang; B.-D. Young; S.-H. Ou

2012-01-01

294

Deep seated gravitational slope deformations in the European Alps  

Science.gov (United States)

Deep seated gravitational slope deformations (DSGSD) are widespread phenomena, recognized in different mountain ranges worldwide. The distribution of such phenomena at the scale of a mountain belt has rarely been systematically analysed in the past. Aim of the paper is to present and discuss an inventory map of DSGSD at the scale of the entire European Alps, in order to review existing knowledge and investigate general controls on these phenomena. The criteria adopted for their classification and distinction are presented. A total of 1033 DSGSDs, ranging in size between 0.03 and 108 km2, have been mapped. The inventory has been validated against available local or regional landslide inventories at different scales and prepared by different authors using different approaches. The frequency-area relationship for the mapped features is presented. The spatial distribution of the mapped DSGSD has been quantified by discretizing the study area into regular square grids with different resolution, and analysed with respect to a variety of geological, geomorpohological and morphometric variables, and of their clustering. Discriminant, principal component and cluster analyses have been performed to define the most important controlling and predisposing factors. Results suggest that the occurrence of foliated metamorphic rocks, LGM ice thickness, local relief (and related parameters), slope size, drainage density and river stream power are the local parameters most positively correlated to DSGSD occurrence. The impact of these phenomena on slope morphology, in terms of hypsometry and slope gradient adjustment is also discussed.

Crosta, G. B.; Frattini, P.; Agliardi, F.

2013-10-01

295

Kinetics of polypyrrole electrogeneration on Pt through Tafel slopes  

Energy Technology Data Exchange (ETDEWEB)

A study of the Tafel slopes and the subsequent reaction orders, as a function of monomer and electrolyte concentrations, in different electrolytic medias, for polypyrrole electrogeneration, is presented. The evolution of the Tafel representations is similar in all the analyzed systems (acetonitrile, water and acetonitrile +2% of water). Two straight lines with a net change of slope are always present. The change of the Tafel slope is associated to a change of the electrode mechanism, due to the evolution of the chemical nature of the electrode surface from a bare platinum electrode to a polypyrrole coated electrode. The empirical kinetics obtained from the region of lower slope values (coated electrode), are: Rp = Pyrrole[sup x]ClO[sub 4-][sup y], with x = 0.5, for the three studied systems, and y = 0.5, 0.7, 0.5 for acetonitrile, water and acetonitrile/water solutions respectively, in agreement with reaction orders obtained from a gravimetric following of the electrogenerated polymer. (orig.)

Otero, T.F. (U.P.V., Facultad de Quimica, Lab. de Electroquimica, San Sebastian (Spain)); Rodriguez, J. (U.P.V., Facultad de Quimica, Lab. de Electroquimica, San Sebastian (Spain))

1993-03-22

296

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.

2010-01-01

297

Disturbed zones and displacement back analysis for rock slopes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Firstly the displacements both from field measurements and from finite element method are analyzed to demonstrate that the disturbed zones should be considered in the displacement back analysis of the ship lock slopes of the Three Gorges Project and that elasticity is the feasible constitutive relat...

Deng, J; Lee, CF; Ge, X

298

The Snowmass Points and Slopes Benchmarks for SUSY Searches  

CERN Multimedia

The ``Snowmass Points and Slopes'' (SPS) are a set of benchmark points and parameter lines in the MSSM parameter space corresponding to different scenarios in the search for Supersymmetry at present and future experiments. This set of benchmarks was agreed upon at the 2001 ``Snowmass Workshop on the Future of Particle Physics'' as a consensus based on different existing proposals.

Allanach, Benjamin C; Blair, G A; Carena, M S; de Roeck, A; Dedes, A; Djouadi, Abdelhak; Gerdes, D W; Ghodbane, N; Gunion, J F; Haber, Howard E; Han, T; Heinemeyer, S; Hewett, J L; Hinchliffe, Ian; Kalinowski, Jan; Logan, H E; Martin, S P; Martyn, H U; Matchev, K T; Moretti, S; Moortgat, F; Moortgat-Pick, G; Mrenna, S; Nauenberg, U; Okada, Y; Olive, Keith A; Porod, Werner; Schmitt, M; Su, S; Wagner, C E M; Weiglein, Georg; Wells, J; Wilson, G W; Zerwas, Peter M

2002-01-01

299

Hydrological and geopedological dynamics of a forested slope  

Science.gov (United States)

Though forested watersheds are really particular in terms of hydrodynamics, most of the hydrological models oversimplify the phenomena involved. More investigations are unavoidable to improve the knowledge and the modelling of this environment. Here is the aim of this study. The studied slope is located on the Houille watershed in the West of the Belgian Ardenne (50°1'47''N, 4°53'22''E) on a silty rocky soil. The site is situated under a Douglas fir (Pseudotsuga menziesii (MIRB.) FRANCO) and spruce stand cover (Picea abies (L.) Karst). It is about 160 meters long with a North-West facing slope between 7 and 55%. The goal of the study is : - to characterise the hydrological and pedogeological dynamics along a forested slope, - to compare these dynamics with the tree growth. For the geopedological part of the study, eight pits were dug to describe the soil and take some soil samples used for granulometric, chemical, etc. analysis. We have used geophysical methods (Electrical Resistivity Tomography and Ground Penetrating Radar) to estimate the soil depth. As for the hydrological part of this study, moisture sensors (capacitive and TDR) have been installed in the pits along the slope. A dye tracing test has been performed to underline the preferential flow and the importance of the subsurface flow. Several trees have been equipped with dendrometers and some measures of the LAI and the height of the trees are planned. The poster will present the first results of these investigations.

Deraedt, Deborah; Colinet, Gilles; Degré, Aurore

2013-04-01

300

Centrifuge model tests of cohesive soil slopes during rainfall  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Centrifuge model tests were conducted to investigate the deformation and failure mechanism of cohesive soil slopes due to rainfall. A rainfall simulator was used to produce the rainfall during the tests. The failure modes and deformation processes were observed photographically and measured by corre...

Qian, J; Zhang, G; Zhang, J; Lee, C

 
 
 
 
301

Soil slips and debris flows on terraced slopes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 trigger...

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

302

Slope Modulation of the Radar Backscatter by Sea Waves.  

Science.gov (United States)

Measured data of the radar backscatter as a function of incidence angle were investigated to study the influence of the slope modulation by the sea waves on the total modulation observed for the radar backscatter of the sea. Analysis suggests that much if...

G. P. Deloor

1988-01-01

303

Drilled Piers Used for Slope Stabilization: Final Report (Revised).  

Science.gov (United States)

Large diameter drilled piers discretely placed so that some clear space exists between the piers can take advantage of the arching action of the soil to form a continuous barrier. The drilled piers improve the stability of the slope in two ways: by transm...

J. L. Chameau M. W. Oakland

1986-01-01

304

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Rasheed A. Adebimpe; Jide Muili Akande; Chinwuba Arum

305

Experimental research on stability of covering blocks for sloping banks  

International Nuclear Information System (INIS)

[en] 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.)

1988-01-01

306

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...

307

Overtopping And Rear Slope Stabillity Of Reshaping Breakwaters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 s...

Burcharth, Hans Falk; Lykke Andersen, Thomas

308

Early warning thresholds for partially saturated slopes in volcanic ashes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rainfall-induced landslides in steep soil slopes of volcanic origin are a major threat to human lives and infrastructure. In the context of constructing early warning systems in regions where extensive data on landslide occurrences and associated rainfall are inexistent, physically based tools offer...

Eichenberger, John; Ferrari, Alessio; Laloui, Lyesse

309

Slope stability assessment for historical monument management, Machu Picchu, Peru.  

Czech Academy of Sciences Publication Activity Database

. Zittau : DGGT, 2009. s. 413.[Conference on Engineering Geology and Forum Young Engineering Geologists /17./. 07.05.2009-10.05.2009, Zittau]Grant CEP: GA ?R GP205/09/P383Výzkumný zám?r: CEZ:AV0Z30460519Klí?ová slova: slope stabilityKód oboru RIV: DB - Geologie a mineralogie

Klimeš, JanG

310

Generalised framework of limit equilibrium methods for slope stability analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A generalised framework is proposed in this paper incorporating almost all of the existing limit equilibrium methods of slices for slope stability analysis with general slip surfaces. The force and moment equilibrium equations are derived in terms of the factor of safety and the initially assumed no...

Zhu, DY; Lee, CF; Jiang, HD

311

A New Closure to Slice Model for Slope Stability Analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a new closure to slice models for evaluating slopes. The discussion is based on the minimal inter-slice action (MIA) hypothesis, which results in a new slice model without including artificially adjustable parameters. It has been realized that the new slice model predicts the min...

Tianyun Liu; Yunling Duan; Chongbin Zhao

312

The use of an SQP algorithm in slope stability analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the upper bound approach to limit analysis of slope stability based on the rigid finite element method, the search for the minimum factor of safety can be formulated as a non-linear programming problem with equality constraints only based on a yield criterion, a flow rule, boundary conditions, an...

Chen, J; Yin, JH; Lee, CF

313

The Snowmass Points and Slopes: benchmarks for SUSY searches  

International Nuclear Information System (INIS)

The ''Snowmass Points and Slopes'' (SPS) are a set of benchmark points and parameter lines in the MSSM parameter space corresponding to different scenarios in the search for Supersymmetry at present and future experiments. This set of benchmarks was agreed upon at the 2001 ''Snowmass Workshop on the Future of Particle Physics'' as a consensus based on different existing proposals. (orig.)

2002-01-01

314

Soil organic carbon redistribution and budget of erosion and deposition in a sloping field  

International Nuclear Information System (INIS)

A sloping field of black soil in northeast China was selected to conduct soil redistribution for the past nearly 50 and 100 years, and to calculate the carbon budget by using 137Cs and fly ash tracer techniques. The results showed that the depth of original buried layer in foot-slope and toe-slope located at 70 and 80 cm respectively, and the content of SOC was 5.23 and 0.43 g/kg more than those of overlying soil. Summit, shoulder-slope and back-slope suffered erosion with the rate of 0.2, 5 and 2.2 mm/yr, respectively based on distribution of 137Cs and fly ash with soil depth. The depths of fly ash attainment in foot-slope and toe-slope were 70 and 80 cm respectively, and were well consistence with their buried surface horizon, which indicated the depositional areas had been annually plowed before locomotives used. Most of the eroded soil materials in depositional areas were from shoulder-slope and back-slope, accumulated in foot-slope firstly, then transferred to toe-slope gradually according to soil surface of various years. The loss of SOC in summit, shoulder-slope and back-slope was 683 kg in all in the past nearly 100 years, among which 418 kg (about 60%) was accumulated in foot-slope and toe-slope depressions, 257 kg of soil carbon was accumulated in most recent 50 years. (authors)

2005-01-01

315

[Causes and factors associated with collisions on ski slopes].  

UK PubMed Central (United Kingdom)

BACKGROUND: Annually, in Austria more than 10 million people participate in winter sport activities such as alpine skiing, snowboarding, cross country skiing and ski touring. About 80 - 90 % of all accidents are caused by a fall without other people involved and about 10 % are caused by collisions between people. METHODS: In the winter season 2011/2012, skiers and snowboarders injured due to a fall or a collision on a ski slope have been interviewed about potential intrinsic and extrinsic risk factors in the Austrian province Vorarlberg. RESULTS: In total, 1741 people injured by a self-inflicted fall and 137 people injured due to a collision have been interviewed. People injured due to a collision showed more often a head injury (15 vs. 8 %) and more often a concussion (15 vs. 6 %). Furthermore, people injured due to a collision were significantly older (41 vs. 33 years) and showed a higher proportion of skiers (86 vs. 79 %) as well as of higher skilled people (83 vs. 74 %) compared to those injured by a self-inflicted fall. Collisions between sport participants incurred significantly more often on slope intersections (11 vs. 4 %), when more people were on ski slopes (30 vs. 12 %) and when the sun was shining (85 vs. 69 %). CONCLUSION: According to the results of this study, preventive recommendations to reduce the risk of a collision include an adaptation of the individual skiing or snowboarding behaviour and the actual speed on skill level, weather conditions and number of other skiers and snowboarders on ski slopes. In addition, influences of adaptive visual information and supervision systems at slope intersections and in relation to weather and traffic conditions should be evaluated.

Ruedl G; Kopp M; Burtscher M; Bauer R; Benedetto K

2013-05-01

316

Flow during the evening transition over steep alpine slopes  

Science.gov (United States)

In steep alpine environments, surface heating and cooling plays an important role on the wind circulation, turbulence and flow patterns. These circulations undergo a strong diurnal cycle, with upslope winds during the day and drainage winds at night. Little is known about the transition between these two wind regimes over very steep slopes due to the difficulties involved with making field measurements. In both summers 2010 and 2011, we conducted a field campaign on a steep, west-facing slope of the Swiss Alps (Val Ferret, Valais) to study the evening transition of slope flows. Two eddy-covariance towers and two weather stations were installed on an experimental transect with slopes ranging from 20° to 45°. Large-scale valley circulations were observed with tethered balloon profiling and a wind lidar. The results show that topographic shading controls the daytime slope flow destruction and initiation of the evening transition. Following the movement of a 'shading front', the incoming shortwave radiation decreases by several hundreds of W/m2 in just a few minutes. The associated reduction in skin temperatures is substantial, and reductions on the order of 10°C in less than 10 min can be observed. This is followed by an early-evening calm period with light wind speeds and very small turbulent kinetic energy (TKE). Finally, growing from the surface upwards, a shallow, local katabatic flow (skin flow) forms. Additionally, an analysis of the TKE budget close to the surface shows that the buoyancy flux overpowers the shear production in the last hours before the local sunset, while at night shear production dominates the TKE budget.

Parlange, M. B.; Nadeau, D. F.; Pardyjak, E.; Oldroyd, H. J.; Calaf Bracons, M.; Daniels, M. H.; Higgins, C. W.; Huwald, H.

2011-12-01

317

The ecological response of fern diversity to different slopes in Gudoushan Nature Reserve, Guangdong  

Directory of Open Access Journals (Sweden)

Full Text Available In order to examine the effect of slope differences on fern diversity, we chose 10 plots (5×5 m2 for each plot) on east-, west-, south-, and north-facing slopes, with altitudes ranging from 20 to 986 m in Gu-doushan Nature Reserve, Xinhui, Guangdong, China. We obtained the following results: (1) Species abun-dance on the east- and north-facing slopes were high, while that on the west- and south-facing slopes were low. (2) Similarity indices of ferns in different slope orientations were low (<0.5), which suggested that ori- entation significantly influenced fern diversity. The difference between the south- and north-facing slopes (similarity index, 0.2895) and the similarity between west- and south-facing slopes (similarity indices, up to 0.4643) were the most obvious. (3) Tropical ferns were dominant in sunny slopes, while non-tropical ferns were dominant in shady slopes. The percentage of tropical ferns on the south-, west-, east-, and north-facing slopes decreased, while that of non-tropical ferns increased. (4) Shade ferns were dominant in shady slopes, while sunny ferns were dominant in sunny slopes; the number of shade ferns regularly increased on the south-, west-, east-, and north-facing slopes. These results clearly indicated how light and heat on different slopes affected fern diversity and suggested that fern diversity could be a good indicator of environmental and climatic changes.

Yuehong Yan; Zuxia He; Hu Yuan; Fuwu Xing

2011-01-01

318

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)

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

Kubota, Tetsuya; Shinohara, Yoshinori; Aditian, Aril

2013-04-01

319

Alterações radiográficas do tálus no pé torto congênito após liberação cirúrgica pela técnica de McKay Radiographic abnormalities of the talus in patients with clubfoot after surgical release using the McKay technique  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: Analisar as alterações morfológicas do tálus após o tratamento cirúrgico do pé torto congênito pela técnica de McKay. MÉTODO: Foram analisadas, retrospectivamente, radiografias em perfil com carga dos pés de 14 pacientes com pé torto congênito unilateral submetidos ao tratamento pela técnica de McKay por dupla incisão. Todos os pacientes foram operados pelo mesmo cirurgião, com média de 6,53 anos entre a cirurgia e a radiografia. Comparamos as características do tálus dos pés operados com os parâmetros radiográficos dos pés contralaterais. Avaliamos a presença de deformidade do dômus e da cabeça do tálus (avaliação da esfericidade); a altura e o comprimento do tálus; a presença e grau de subluxação do navicular; a alteração do ângulo de Gissane; e o padrão do trabeculado ósseo. RESULTADOS: Alterações da cabeça do tálus ocorreram em 92,8% dos casos; do dômus em 92,8%; e do trabeculado em 100%. A relação entre o comprimento do tálus do pé operado sobre o contralateral variou de 0,61 a 0,88 (média de 0,79; DP = 0,09), e da altura de 0,57 a 0,98 (média de 0,82; DP = 0,12). O ângulo de Gissane aumentou em todos os pés operados, e todos apresentaram subluxação do navicular, com índice variando de 6,43 a 59,75% (média de 26,34%; DP = 16,66%). CONCLUSÃO: Alterações talares ocorreram em 100% dos pés tratados pela técnica de McKay. Estabelecer parâmetros radiográficos para descrever e quantificar essas deformidades mostrou-se viável, através de técnicas simples e de fácil execução.OBJECTIVE: To analyze morphological abnormalities of the talus in patients with clubfoot after surgical treatment using the McKay technique. METHOD: Lateral standing-position radiographs of the feet of 14 patients with unilateral clubfoot who underwent treatment by means of the double-incision McKay technique were retrospectively analyzed. All the patients were operated by the same surgeon, with an average of 6.53 years between surgery and the radiograph. We compared the radiographic characteristics of the talus between the operated and the contralateral foot. We assessed the presence of deformity of the talar dome and head (sphericity evaluation); the talar length and height; the percentage and degree of navicular subluxation; abnormalities of the Gissane angle; and the trabecular bone pattern. RESULTS: Abnormalities of the talar head occurred in 92.8% of the patients; of the talar dome in 92.8%; and of the trabecular pattern in 100%. The talar length ratio between the operated and the contralateral foot ranged from 0.61 to 0.88 (mean 0.79; SD = 0.09), while the height ratio ranged from 0.57 to 0.98 (mean 0.82; SD = 0.12). The Gissane angle was greater in all of the operated feet, and all of them also showed navicular subluxation, at a rate ranging from 6.43 to 59.75% (mean 26.34%; SD = 16.66%). CONCLUSION: Talar abnormalities occurred in 100% of the feet treated using the McKay technique. It was shown that establishing radiographic parameters to describe and quantify these deformities was feasible, through simple and easy-to-perform techniques.

José Antonio Pinto; Andréa Canizares Hernandes; Thais Paula Buchaim; Francesco Camara Blumetti; Carla Chertman; Patrícia Corey Yamane; Artur da Rocha Corrêa Fernandes

2011-01-01

320

Quantitative laboratory observations of internal wave reflection on ascending slopes  

CERN Multimedia

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.

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

2006-01-01

 
 
 
 
321

Case studies of slope stability radar used in coal mines  

Energy Technology Data Exchange (ETDEWEB)

This paper presents case studies about how the Slope Stability Radar (SSR) system provided adequate warning to safeguard people and equipment prior to highwall and low wall failure at two Australian coal mines. At Drayton mine, the SSR was able to provide the mine with sufficient warning to move the shovel and trucks away from the highwall, while personnel safely watched 50,000 tonnes of bulk material coming down from the wall. At Mt Owen mine, the SSR alarm allowed the mine to evacuate equipment and personnel four hours prior to a 30,000,000 tonne low wall failure. These two case studies demonstrate how the SSR system was able to continuously monitor the stability of these critical slopes, enabling greater mine productivity whilst maintaining the highest quality of safety. 2 refs., 7 figs., 1 tab.

Noon, D. [GroundProbe Pty Ltd., South Brisbane, Qld. (Australia)

2005-07-01

322

ARRA additions to the north slope of Alaska.  

Energy Technology Data Exchange (ETDEWEB)

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.

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

323

Surface Slope Metrology on Deformable Soft X-ray Mirrors  

International Nuclear Information System (INIS)

[en] 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.

2009-10-02

324

Alaska North Slope oil-field restoration research strategy. Manual  

Energy Technology Data Exchange (ETDEWEB)

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.

Wyant, J.G.; Knapp, C.M.

1992-03-01

325

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)

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.

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

2012-04-01

326

Random Intercept and Random Slope 2-Level Multilevel Models  

Directory of Open Access Journals (Sweden)

Full Text Available Random intercept model and random intercept & random slope model carrying two-levels of hierarchy in the population are presented and compared with the traditional regression approach. The impact of students’ satisfaction on their grade point average (GPA) was explored with and without controlling teachers influence. The variation at level-1 can be controlled by introducing the higher levels of hierarchy in the model. The fanny movement of the fitted lines proves variation of student grades around teachers.

Rehan Ahmad Khan; Shahid Kamal

2012-01-01

327

Gravel pad restoration on Alaska`s North Slope  

Energy Technology Data Exchange (ETDEWEB)

Federal and state permits for North Slope oil development stipulate that sites used for exploration and production operations must eventually be returned to a condition acceptable to the regulating agencies and the landowner. In cooperation with the University of Alaska Fairbanks and regulatory agencies, BP Exploration (Alaska) Inc. (BPXA) has been researching and testing rehabilitation measures for abandoned exploration facilities. Results from these studies am identifying effective ways to assure that disturbed sites will provide usable wildlife habitat after field abandonment.

Herlugson, C.J.; McKendrick, J.D. [Univ. of Alaska, Fairbanks, AK (United States); Parnell, J.A.

1996-12-31

328

Time shift of pulses due to dispersion slope and nonlinearity  

Energy Technology Data Exchange (ETDEWEB)

The authors show that the time delay of optical pulses traveling in long fibers is influenced by the dispersion slope and the fiber nonlinearity. Consequently, one or more new pulses that are inserted by add-drop operations into a pulse train that has already traveled a long distance may shift relative to the old pulses. This time shift delays the initial pulses more than the newly inserted ones, so that the newly inserted pulses can leave their time frames, leading to errors.

Marcuse, D.; Menyuk, C.R.; Holzloehner, R.

1999-12-01

329

Coarsening in surface growth models without slope selection  

CERN Document Server

We study conserved models of crystal growth in one dimension [$\\partial_t z(x,t) =-\\partial_x j(x,t)$] which are linearly unstable and develop a mound structure whose typical size L increases in time ($L = t^n$). If the local slope ($m =\\partial_x z$) increases indefinitely, $n$ depends on the exponent = 1/|m|^\\gamma$): $n=1/4$ for $1< \\gamma <3$ and $n=(1+\\gamma)/(1+5\\gamma)$ for

Politi, P; Politi, Paolo; Torcini, Alessandro

2000-01-01

330

Unitarity lower bounds on logarithmic slope of diffraction peak  

International Nuclear Information System (INIS)

Via Lagrange multipliers for equality and inequality constraints, rigorous lower bounds on the logarithmic slope of diffraction peak are derived assuming unitarity and a fixed total elastic ?sub(el) and forward differential d?sub(el)/d? (0deg) cross section. Comparison with the experimental data of antip p and pp scattering shows that the relative departure from the unitarity bound is about 11% for all Psub(LAB) > 1 GeV/c. (author).

1981-01-01

331

Children's locomotion on slopes given visual, acoustic, and tactile information.  

UK PubMed Central (United Kingdom)

The effects of visual, acoustic, and tactile information on 5 blind and 5 sighted children's locomotion on slopes (10 degrees, 15 degrees, 20 degrees, 25 degrees, and 30 degrees) were investigated. Children's ages ranged from 5.8 to 7.7 years (M= 6.8, SD= 0.7). The sighted children performed the task of walking up and down different slopes blindfolded and with full vision. Locomotion modes, locomotor skill, gait deviation, and time to complete the task were analyzed. Walking was the preferred locomotion mode up to 20 degrees, but steeper slopes were perceived as "non-walkable." Doubly multivariate MANOVAs revealed an effect of visual information (blindfolded vs full vision) on the sighted children's gait patterns, and a significant interaction between cue condition and group (blind vs blindfolded), underlining a distinct influence of the cues in the gait patterns of the two groups of children. Acoustic and tactile cues were generally more effective for the blind than for the sighted blindfolded children.

Alexandre R; Cordovil R; Barreiros J

2012-08-01

332

Concerning the Slope of the Cepheid Period-Luminosity Relation  

CERN Document Server

We discuss the impact of possible differences in the slope of the Cepheid Period-Luminosity relation on the determination of extragalactic distances in the context of recent studies that suggest changes in this slope. We show that the Wesenheit function W = V - R x ((V-I), widely used for the determination of Cepheid distances, is expected to be highly insensitive to changes in the slope of the underlying (monochromatic) Period-Luminosity (PL) relations. This occurs because the reddening trajectories in the color-magnitude plane are closely parallel to lines of constant period. As a result W-based Period-Luminosity relations have extremely low residual dispersion, which is because differential (and total line-of-sight) reddening is eliminated in the definition of W and the residual scatter due to a star's intrinsic color/position within the Cepheid is also largely insensitive to W. Basic equations are presented and graphically illustrated, showing the insensitivity of W to changes in the monochromatic PL rela...

Madore, Barry F

2009-01-01

333

DEVELOPMENT OF SHALLOW VISCOUS OIL RESERVES IN NORTH SLOPE  

Energy Technology Data Exchange (ETDEWEB)

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. In the last quarter, we have developed streamline generation and convection subroutines for miscible gas injection. The WAG injection algorithms are being developed. We formulated a four-phase relative permeability model based on two-phase relative permeabilities. The new relative permeability formulations are being incorporated into the simulator. Wettabilities and relative permeabilities are being measured. Plans for the next quarter includes modeling of WAG injection in streamline based simulation, relative permeability studies with cores, incorporation of complex well-architecture.

Kishore K. Mohanty

2003-07-01

334

DEVELOPMENT OF SHALLOW VISCOUS OIL RESERVES IN NORTH SLOPE  

Energy Technology Data Exchange (ETDEWEB)

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. In the last quarter, we added numerical solution along streamline subroutines to our streamline compositional simulator. The WAG injection algorithms are being developed. We studied the wettability of the reservoir oil and formulated a four-phase relative permeability model based on two-phase relative permeabilities. The effect of new relative permeability formulations on a five-spot pattern WAG recovery was evaluated. Effect of horizontal wells on pattern sweep has been initiated. A model quarter five-spot experiment is being designed. Plans for the next quarter includes modeling of WAG injection in streamline based simulation, evaluation of complex well-architecture and design of model quarter five-spot experiment.

Kishore K. Mohanty

2003-07-01

335

Monitoring slope deformation with quadrilaterals for pipeline risk management  

Energy Technology Data Exchange (ETDEWEB)

A quadrilateral is a geometric form defined by 4 points in an approximately square plan configuration. Quadrilateral measurements can be used to calculate ground-surface deformation and strain, and can serve as an economical alternative to the placement of strain gauges on pipelines in areas of active or potential slope movements. This paper provided details of a study in which 3 contiguous quadrilaterals were installed in a landslide-prone area of southern California to aid in the monitoring of a slope between the main scarp of a recently active landslide and a pipeline bridge foundation. Repeated measurements of the distances between the points and relative elevations of the quadrilaterals allowed for the calculation of displacements across landslide cracks and strains and tilts on landslide surfaces. Results of the study showed that inferences about pipeline strain may be made based on quadrilateral-based ground surface strain. Quadrilaterals place directly over or in close proximity to the buried pipeline provided the most valuable data. It was observed that while earth movements were transferred to the buried pipeline, soil-pipeline interaction effects resulted in more deformation of the soil than in the pipeline. The study also suggested that quadrilaterals can also be used to provide quantitative slope deformation data for pipeline risk management processes. It was concluded that quadrilaterals are well-suited for the monitoring of ground settlement, lateral, or rotational ground movement, as well as subsidence, uplift, and creep. 5 refs., 5 tabs., 7 figs.

Keaton, J.R. [AMEC Earth and Environmental, Anaheim, CA (United States); Gailing, R.W. [Southern California Gas Co., Los Angeles, CA (United States)

2004-07-01

336

The slope of the GRB Variability/Peak Luminosity Correlation  

CERN Document Server

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...

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

2006-01-01

337

Mutagenic activity of heavy metals in soils of wayside slopes  

Science.gov (United States)

The genotoxic properties of soils polluted with heavy metals were studied on two wayside slopes covered with trees in the city of Voronezh. The nucleolar test in cells of the apical meristem of Zebrina pendula Schnizl. roots was used. The genotoxic effect of the soils was revealed according to the increased number of 2-and 3-nucleolar cells (from 41 to 54% and from 19 to 23% in the upper part of the first and second slopes, respectively; in the control, their number was 18 and 7%). The mean number of nucleoli per cell increased from 1.7 to 1.95 in the experiment and 1.31 in the control. The increased vehicle emissions, especially when cars go up the slopes (mainly in the upper and middle parts), correlated with the elevated heavy metal (Pb, Cu, Cd, and Zn) contents in the soil. The mutagenic substances may be removed to the Voronezh Reservoir, where they may be accumulated in some living organisms.

Fedorova, A. I.; Kalaev, V. N.; Prosvirina, Yu. G.; Goryainova, S. A.

2007-08-01

338

Late Cretaceous terrestrial vertebrate fauna, North Slope, Alaska  

Energy Technology Data Exchange (ETDEWEB)

Closely related terrestrial vertebrates in Cretaceous mid-latitude (30/sup 0/ to 50/sup 0/) faunas of North America and Asia as well as scattered occurrences of footprints and skin impressions suggested that in the Late Mesozoic the Alaskan North Slope supported a diverse fauna. In 1961 abundant skeletal elements of Cretaceous, Alaskan dinosaurs (hadrosaurids) were discovered by the late R.L. Liscomb. This material is being described by K.L. Davies. Additional fossils collected by E.M. Brouwers and her associates include skeletal elements of hadrosaurid and carnosaurian (.tyrannosaurid) dinosaurs and other vertebrates. The fossil locality on the North Slope is not at about 70/sup 0/N. In the Late Cretaceous the members of this fauna were subject to the daylight regime and environment at a paleolatitude closer to 80/sup 0/N. Current hypotheses attributing extinctions of dinosaurs and some other terrestrial vertebrates to impact of an extraterrestrial object cite periods of darkness, decreased temperature (possibly followed by extreme warming) and acid rain as the direct causes of their demise. Unless members of this North Slope fauna undertook long-distance migrations, their high latitude occurrence indicates groups of dinosaurs and other terrestrial vertebrates regularly tolerated months of darkness.

Clemens, W.A.; Allison, C.W.

1985-01-01

339

Slope stability probability classification, Waikato Coal Measures, New Zealand  

Energy Technology Data Exchange (ETDEWEB)

Ferm classified lithological units have been identified and described in the Waikato Coal Measures in open pits in the Waikato coal region. These lithological units have been classified geotechnically with mechanical tests and discontinuity measurements. Using these measurements, slope stability probability classification (SSPC) have been quantified based on an adaption of Hack's SSPC system which places less influence on rock quality designation and unconfined compressive strength than previous rock mass rating systems. An attempt has been made to modify the Hack weathering susceptibility rating by using chemical index of alteration values from XRF major element analysis. Another major component of this adapted SSPC system is the inclusion of rock moisture content effects on slope stability. The paper explains the systematic initial approach of using the adapted SSPC system to classify slope stability in the Waikato open pit coal mines. The XRF major element results obtained for lithologies in the Waikato coal region may be a useful mine management tool to quantify stratigraphic thickness and palaeoweathering from wash drill cuttings. 14 refs., 7 figs., 3 tabs.

Lindsay, P.; Campbell, R.; Fergusson, D.A.; Ferm, J.C.; Gillard, G.R.; Moore, T.A. [CRL Energy Ltd., Christchurch (New Zealand)

1999-07-01

340

REVEGETATION POTS AND ITS MANUFACTURING METHOD OF ROCK SLOPES  

UK PubMed Central (United Kingdom)

A flowerpot for afforesting a rock slope is provided to enable the stabilization and early afforestation of the rock slope at low costs. A flowerpot(1) for afforesting a rock slope comprises: a plant growing part(10) which is formed into one half or less of the total length of the flowerpot and 1~10 drains, each of which is formed at the bottom of the flowerpot and has a diameter of pi 8~10mm. The flowerpot is made of at least one kind selected from the group consisting of high molecular substances such as loess, clay, PVC, plastic, and rubber. The flowerpot has a total length of 200~1000mm and a diameter of 100~500mm, and the plant growing part has a length of 100~500mm. The flowerpot has a round or square shape, and the rear part of the round-shaped flowerpot has 1~5 grooves(12) in the from of at least one kind selected from a horizontal shape, a vertical shape, a U-shape, and a V-shape. In addition, a support is placed at the lowest part of the flowerpot, and a separation plate is formed at a height of 10~20mm from the lower part of the flowerpot.

MA HO SEOP; PARK JIN WON

 
 
 
 
341

CONCERNING THE SLOPE OF THE CEPHEID PERIOD-LUMINOSITY RELATION  

International Nuclear Information System (INIS)

We discuss the impact of possible differences in the slope of the Cepheid period-luminosity (PL) relation on the determination of extragalactic distances in the context of recent studies that suggest changes in this slope. We show that the Wesenheit function W = V - R x (V - I), widely used for the determination of the Cepheid distances, is expected to be highly insensitive to changes in the slope of the underlying (monochromatic) PL relations. This occurs because the reddening trajectories in the color-magnitude plane are closely parallel to lines of constant period. As a result W-based PL relations have extremely low-residual dispersion, which is because differential (and the total line of sight) reddening is eliminated in the definition of W and the residual scatter due to a star's intrinsic color/position within the Cepheid is also largely insensitive to W. Basic equations are presented and graphically illustrated, showing the insensitivity of W to changes in the monochromatic PL relations.

2009-05-10

342

Comparison of slope stability in two Brazilian municipal landfills.  

UK PubMed Central (United Kingdom)

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.

Gharabaghi B; Singh MK; Inkratas C; Fleming IR; McBean E

2008-01-01

343

Comparison of slope stability in two Brazilian municipal landfills.  

Science.gov (United States)

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

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

2007-09-25

344

ANALYSIS OF EXISTING METHODS OF STUDY OF STRAIN-STRESS STATE OF ROCKS ON SLIP SLOPE  

Directory of Open Access Journals (Sweden)

Full Text Available The methods for analysis of strain-stress state of rocks on slip slope as well as the methods of study of engineering and geological properties of rocks that compose the slip slope are considered.

Ye. Ugnenko; O. Tymchenko

2010-01-01

345

Advanced Technology for Soil Slope Stability. Volume 2. Sample Problems and Case Histories.  

Science.gov (United States)

The purpose of this manual is to provide engineers and geologists involved highway design and construction with a common understanding and approach to slope stability analysis for highway projects. The material encompasses general highway slope stability ...

G. Boyce L. Abramson S. Sharma T. Lee

1994-01-01

346

?????? ???????????? ???????????? ??? ??????? ????????? ?? ???????? ?????????? ??????? ???????? ??????? ?nalysis of the effectiveness of countermeasures to protect the ecosystems on slopes landscapes using box models ?????? ????????????? ???????? ??? ?????? ????????? ?? ????????? ?????????? ??????? ???????? ???????  

Directory of Open Access Journals (Sweden)

Full Text Available  ??? ??????? ???????????? ???????????? ??? ??????? ????????? ??? ?????????????? ??????????? ???????? ????-????? ???????? ??????????. ????????? ??????????? ???????? ???????? ????????????? ? ???????? ??????????? ??????? ???????? ??????? ?? ????????????? ????????????. ?????????? ??????????? ?????????? ??????? ?? ?????? ??????????? ????????  ??????  ????????????. For the analysis of efficiency of counter-measures on defence of ecosystems  from radioactive contamination is created block-scheme  of  slope`s ecosystem. The design of processes of migration of radionuclides in slope`s  ecosystems  is conducted by the method  of box models  with the use of counter-measures.  The results of design allow to estimate and choose the optimum algorithm  of choice of counter-measures.   ??? ??????? ????????????? ???????? ??? ?????? ????????? ?? ?????????????? ??????????? ?????????? ?? ????-????? ????????? ??????????. ????????? ????????????? ????????? ???????? ????????????? ? ????????? ??????????? ??????? ???????? ??????? ? ?????????????? ????????. ?????????? ????????????? ????????? ??????? ? ??????? ??????????? ???????? ?????? ????????.

?.?. ??????????; ?.?. ???????????

2006-01-01

347

Effects of some geometric parameters of slope failures on operational safety of bucket wheel excavators  

Energy Technology Data Exchange (ETDEWEB)

The results are analyzed of investigations carried out in the Turow I and Turow II brown coal mines in Poland into effects of slope failures on operational safety of the SchRs-1200 and SchRs-800 bucket wheel excavators. One hundred cases of slope failures were comparatively evaluated. Effects of slope failures on bucket wheel excavators and belt conveyors depending on slope dimensions (height), geometry, rock physical and mechanical properties and position of an excavator or a belt conveyor in relation to slope failure area were investigated. Slope height ranged from 10 to 35 m and angle of slope inclination from 45 to 63 degrees. Analyses show that accurate forecasting of slope failure range in 75% of cases depends on slope height, angle of slope inclination and soil cohesion analysis. Equations for forecasting slope failure range are derived. On the basis of analyses, recommendations are made on the safe distance from bucket wheel excavators and belt conveyors to slopes in brown coal surface mines in Poland with conditions comparable to those in the Turow I and the Turow II mines. 5 references.

Mazurek, J.

1984-06-01

348

Stability of submarine slopes in the northern South China Sea: a numerical approach  

Science.gov (United States)

Submarine landslides occur frequently on most continental margins. They are effective mechanisms of sediment transfer but also a geological hazard to seafloor installations. In this paper, submarine slope stability is evaluated using a 2D limit equilibrium method. Considerations of slope, sediment, and triggering force on the factor of safety (FOS) were calculated in drained and undrained ( ?=0) cases. Results show that submarine slopes are stable when the slope is 13° with earthquake peak ground acceleration (PGA) of 0.5 g; whereas with a weak layer, a PGA of 0.2 g could trigger instability at slopes >10°, and >3° for PGA of 0.5 g. The northern slope of the South China Sea is geomorphologically stable under static conditions. However, because of the possibility of high PGA at the eastern margin of the South China Sea, submarine slides are likely on the Taiwan Bank slope and eastern part of the Dongsha slope. Therefore, submarine slides recognized in seismic profiles on the Taiwan Bank slope would be triggered by an earthquake, the most important factor for triggering submarine slides on the northern slope of the South China Sea. Considering the distribution of PGA, we consider the northern slope of the South China Sea to be stable, excluding the Taiwan Bank slope, which is tectonically active.

Zhang, Liang; Luan, Xiwu

2013-01-01

349

Implications of turbulence slope variations in different approaches  

Directory of Open Access Journals (Sweden)

Full Text Available Both heart rate variability (HRV) and heart rate turbulence (HRT) are established tools to study cardiac autonomic activity. Short-term studies of HRV had been reported to be stable for autonomic function assessment. However, there is little information on whether short-term HRT assessment is comparable to 24 h assessment. The aim of the study is to identify the relationship of HRT values between the 24 h and isolated tachogram measurements. We collected 24 h Holter recordings from 116 patients attending the outpatient department. HRT parameters were assessed for 24 h. Using the conventional method, HRT parameters were calculated using the average of tachograms over long-term recordings. In an alternative method, HRT parameters were obtained from each tachogram. We calculated a mean value for each subject by averaging the whole HRT data of every tachogram. Correlation analysis between the two groups of HRT values was performed. The results showed a high correlation between the two methods in turbulence slope (TS) (P<0.001; r=0.84) and an extremely significant correlation in turbulence onset (TO) (P<0.001; r=0.99). The values of TS were increased when assessed by separate tachogram. The variations became prominent when TS values calculated by the conventional method were low. HRT is as useful by separate tachogram assessment as by the standard Holter recordings. However, the TS values should be redefined. In subjects with abnormal turbulence slope (<2.5) calculated by averaging long-term recordings, the possibility of TS values blunted by diverse regression slope sequences in separate tachograms should be taken into consideration.

Hung Yi Chen

2011-01-01

350

Observations of drainage winds on a simple slope  

Energy Technology Data Exchange (ETDEWEB)

Katabatic winds observed over a simple slope showed progressive deepening and strengthening with increased downslope distance. The maximum in the downslope wind component increases, and the height of the maximum rises as the flow develops. A measure of the flow depths obtained from the temperature profiles at the Rattlesnake Mountain site near Richland, Washington and the Cobb Mountain site in northern California shows that these depths are insensitive to the details of the ambient conditions, provided the drainage flows are well established. Depths of the katabatically driven winds appeared to be more sensitive to ambient wind directions.

Doran, J.C.; Horst, T.W.

1982-11-01

351

Tidal current variability on the Scotian Shelf and Slope  

Energy Technology Data Exchange (ETDEWEB)

A statistical summary is presented of the variability of the tidal current on the Scotian Shelf and Slope in the Nova Scotia offshore. The data are based on moored current data and on simulated data generated by a barotropic circulation model of the Shelf. Included in the observational data set are 672 separate deployments representing over 2,000 data months of observations. Tidal constituents used in the variability computations for both the observational and modelled data are three semi-diurnal constituents (M2, S2, and N2) and two diurnal constituents (K1 and O1). 10 refs., 9 figs., 2 tabs.

Gregory, D.N.

1988-10-01

352

Total Widths And Slopes From Complex Regge Trajectories  

CERN Document Server

Maximally complex Regge trajectories are introduced for which both Re positive). Our expression reduces to the standard real linear form as the imaginary part (proportional to $\\epsilon$) goes to zero. A scaling formula for the total widths emerges: $\\Gamma_{TOT}/M\\to$ constant for large M, in very good agreement with data for mesons and baryons. The unitarity corrections also enhance the space-like slopes from their time-like values, thereby resolving an old problem with the $\\rho$ trajectory in $\\pi N$ charge exchange. Finally, the unitarily enhanced intercept, $\\alpha_{\\rho}\\approx 0.525$, \

Filipponi, S; Srivastava, Y N

1999-01-01

353

Conservation laws for shallow water waves on a sloping beach  

Directory of Open Access Journals (Sweden)

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.

Yilmaz Akyildiz

1986-01-01

354

Overtopping And Rear Slope Stabillity Of Reshaping Breakwaters  

DEFF Research Database (Denmark)

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 somewhat different from what is valid for a conventional rubble mound breakwater. An overtopping formula fitting the results very well is derived. Unfortunately, the formula is not dimensionless, but an example is presented to show how it can be used anyway. The experiments showed good correlation between overtopping and rear side damage.

Burcharth, Hans Falk; Lykke Andersen, Thomas

2003-01-01

355

Stability analysis of jointed rock slope by the block theory  

International Nuclear Information System (INIS)

[en] 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)

1990-01-01

356

A New Formula for Front Slope Recession of Berm Breakwaters  

DEFF Research Database (Denmark)

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 better than the existing methods, especially in case of more stable structures.

Andersen, Thomas Lykke; Burcharth, Hans F.

2010-01-01

357

Energy approach to calculation of loaded slopes stability / ?????????????? ?????? ? ??????? ???????????? ??????????? ???????  

Directory of Open Access Journals (Sweden)

Full Text Available The computational feasibility of the stability factor of the loaded slope on the basis of the operational analysis of restraining and shear forces which are performed in every point of the flow lineon the further displacements which are arisen by the change of the loads resultant vector is considered. The construction of the most probable flow line is carried out on the basis of the stress analysis of the soil body from the minimum value of the stability factor in it every point. / ??????????????? ??????????? ?????????? ???????? ???????????? ?????? ???????????? ???????????? ?????? ?? ?????? ??????? ????? ???????????? ? ?????????? ???, ??????????? ? ?????? ????? ????? ?????????? ?? ?????????????? ????????????, ??????????? ?? ???? ????????? ???????? ??????? ????????. ?????????? ???????? ????????? ????? ?????????? ?????????? ?? ?????? ??????? ???????????? ????????? ?????????? ??????? ?????? ?? ??????? ????????????? ???????? ???????????? ?????? ???????????? ? ?????? ?? ?????

Bogomolova O. A. / ?????????? ?????? ?????????????; Yechevski A. V. / ???????? ????????? ??????????; Babakhanov B. S. / ????????? ????? ?????????????; Solovev A. V. / ???????? ????????? ????????????; Shiyan S. I. / ???? ????????? ????????; Makhova S. I. / ?????? ???????? ????????; Kalinovski S. A. / ??????????? ?????? ?????????

2011-01-01

358

Instability of dilute granular flow on rough slope  

CERN Multimedia

We study numerically the stability of granular flow on a rough slope in collisional flow regime in the two-dimension. We examine the density dependence of the flowing behavior in low density region, and demonstrate that the particle collisions stabilize the steady flow above a certain density in the parameter region where a single particle would show an accelerated behavior. Within this collisional steady flow regime, however, the uniform steady flow is only metastable and is shown to be unstable against clustering when the particle density is not high enough.

Mitarai, N; Mitarai, Namiko; Nakanishi, Hiizu

2001-01-01

359

Variance-in-Mean Effects of the Long Forward-Rate Slope  

DEFF Research Database (Denmark)

This paper contains an empirical analysis of the dependence of the long forward-rate slope on the long-rate variance. The long forward-rate slope and the long rate are described by a bivariate GARCH-in-mean model. In accordance with theory, a negative long-rate variance-in-mean effect for the long forward-rate slope is documented. Thus, the greater the long-rate variance, the steeper the long forward-rate curve slopes downward (the long forward-rate slope is negative). The variance-in-mean effect is both statistically and economically significant.

Christiansen, Charlotte

2005-01-01

360

Numerical modelling of complex slope deformations (underground mining, rigid jointed rocks)  

Energy Technology Data Exchange (ETDEWEB)

Numerical modelling techniques are applied to the analysis of complex slope deformation problems. The interaction of underground mining and slope instability, the analysis of toppling deformation in a weak rock slope, and deformation due to rigid jointed rocks overlying relatively weak layers were studied. The numerical modelling programs Fast Langrangian Analysis of Continua (FLAC) and Universal Failure mechanisms Distinct Element Code (UDEC) were used. The technique is applied to and analyses are interpreted for the Frank Slide and for slope deformations at the Luscar Mine and in the foundation of Spis Castle in Slovakia. The modelling studies are shown to be relevant to an improved understanding of complex slope deformations.

Benko, B. [University of Saskatchewan, Saskatoon, SK (Canada). Department of Geological Sciences

1997-12-31

 
 
 
 
361

On the maximal number and the diameter of exceptional surgery slope sets  

CERN Multimedia

Concerning the set of exceptional surgery slopes for a hyperbolic knot, Lackenby and Meyerhoff proved that the maximal cardinality is 10 and the maximal diameter is 8. Their proof is computer-aided in part, and both bounds are achieved simultaneously. In this note, it is observed that the diameter bound 8 implies the maximal cardinality bound 10 for exceptional surgery slope sets. This follows from the next known fact: For a hyperbolic knot, there exists a slope on the peripheral torus such that all exceptional surgery slopes have distance at most two from the slope. We also give a simple alternative proof of this fact.

Ichihara, Kazuhiro

2011-01-01

362

[The role of the posterior tibial slope on rupture of the anterior cruciate ligament].  

UK PubMed Central (United Kingdom)

BACKGROUND/AIM: Posterior tibial slope is one of the most citated factors wich cause rupture of the anterior cruciate ligament (ACL). The aim of this study was to determine the association of a greather posterior tibial slope on the lateral condyle, that is a lesser posterior tibial slope on the medial condyle, with ACL rupture. METHODS: The patients were divided into two groups. The study group included the patients with chronic instability of the knee besause of a previous rupture of ACL. The control group included the patients with knee lesion, but without ACL rupture. Posterior tibial slope measuring was performed by sagittal MR slices supported by lateral radiograph of the knee. We measured posterior tibial slope on lateral and medial condyles of the tibia. Using these values we calculated an average posterior tibial slope as well as the difference between slopes on lateral and medial condyles. RESULTS: Patients with ACL rupture have highly statistically significantly greather posterior tibial slope (p < 0.01) on lateral tibial condyle (7.1 degrees : 4.5 degrees) as well as statistically significantly lesser posterior tibial slope (p < 0.05) on medial tibial condyle (5.9 degrees : 6.6 degrees) than patients with intact ACL. CONCLUSION: Great posterior tibial slope on lateral tibial condyle associated with the small posterior tibial slope on the medial tibial condyle, that is a positive differentce between lateral and medial tibial condyles are factors wich may cause ACL rupture.

Stijak L; Blagojevi? Z; Kadija M; Stankovi? G; Djuleji? V; Milovanovi? D; Filipovi? B

2012-10-01

363

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

Directory of Open Access Journals (Sweden)

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.

Juan Wan; Henglin Xiao; Jun He; Lihua Li

2013-01-01

364

Thresholds for the slope ratio in determining transition time and quantifying diffuser performance in situ  

DEFF Research Database (Denmark)

This study is concerned with an objective measure called the slope ratio that can detect acoustic defects due to unexpected pressure increases such as strong reflections and coincidental constructive interference. The slope ratio is the ratio of the instantaneous slope to the mean slope in a decay curve. The slope ratio was suggested for determining the room acoustic transition time experimentally, but its threshold criteria have not been thoroughly investigated. The thresholds for the slope ratio, particularly for applications such as determining the room acoustic transition time and quantifying in situ diffuseness, are examined for various room impulse responses. For the tested rooms, a slope ratio threshold of 11 gives the most consistent and systematic results.

Jeong, Cheol-Ho; Jacobsen, Finn

2012-01-01

365

Dynamic stability and failure modes of slopes in discontinuous rock mass  

International Nuclear Information System (INIS)

[en] 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)

1988-01-01

366

Canopy cover and phytomass comparisons of steep slopes planted to cheatgrass  

Energy Technology Data Exchange (ETDEWEB)

Steep north- and south-facing slopes on an artificially formed earth mound were seeded with cheatgrass in the autumn of 1971 and left unattended. In 1978, canopy cover and phytomass measurements were made on both slopes. The vegetative cover on the north-facing slope provided more canopy cover and more live phytomass than the south-facing slope. Live aboveground phytomass was measured at 830 g/m/sup 2/ on the north-facing slope and 163 g/m/sup 2/ on the south-facing slope. The large amount of primary production on the north-facing slope is attributed to temperature-water relationships rather than to soil nutrient differences because the mound was composed of the same homogeneous mix of soil of common origin.

Rickard, W.H.; Warren, J.L.

1981-01-01

367

Soil slips and debris flows on terraced slopes  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

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

2003-01-01

368

The Modeling of Slopes of Flat Roofs on Marginal Gradients  

Directory of Open Access Journals (Sweden)

Full Text Available Nagrin?jama projektuotoj?, medžiag? gamintoj? ir tiek?j? si?lomi eksploatuojam?j? stog?, skirt? automobili? stov?jimo aikštel?ms, ?rengimo variantai, pateikti Lietuvos Respublikos teis?s akt? reikalavimai šio tipo stogams. Išnagrin?ti stogo nuolydžiai ?vairiose vietose esant ribiniams stogo nuolydžiams. Parodyta, kad naudojant prilydom?sias ritinines dangas esant minimaliam nuolydžiui yra neužtikrinamas eksploatuojamo stogo patikimumas. Si?loma sugriežtinti eksploatuojam? stog? ?rengimo reikalavimus.Straipsnis lietuvi? kalbaThis article is dedicated to study installation options of roofing for parking lots which are proposed by designers, manufacturers and suppliers of materials, the Lithuanian legislative requirements for roofs of this type. Examine the roof slopes at various locations in the roof of the roof marginal gradients. It is shown that at a minimum slope of the roof the reliability of the installed roof is not provided when glued bituminous roofing membranes are used. It is proposed to raise the standards for the existing roof installations.Article in Lithuanian

Romas Rasiulis

2011-01-01

369

Sport Injuries in Iranian Skiers (Shemshak Slope) 2000-2001  

Directory of Open Access Journals (Sweden)

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.

M Gity; M Motamedy

2002-01-01

370

Post-Ellesmerian depositional sequences of central North Slope subsurface  

Energy Technology Data Exchange (ETDEWEB)

Detailed electrical-log correlations of bedding in the Mesozoic to recent intervals define nearly time-equivalent stratigraphic units. Basinal depositional minima separate them into depositional cycles of 15 to 40-m.y. duration, and sequences of similar cycles correspond to the major episodes of Arctic tectonism. The close of the Sag River cycle in Pleinsbachian time ended the Ellesmerian sequence of accretionary tectonics and northerly continental provenance. Long,oscillating uplift to the northwest during the Jurassic Kingak cycle, and five or more subcycles of emergence along an ancestral Barrow arch rift shoulder during the Lower Cretaceous Kup River cycle show that the Barrovian sequence accompanied Arctic rifting. The Brookian sequence records a time of Arctic seafloor spreading coincident with underthrusting of the North Slope block toward a convergent Pacific margin. A series of major overthrusts onto the block from this margin were sources for Lower Torok, Nanushuk, Schrader Bluff, Prince Creek, and Franklin Bluffs cycles. The lower Torok source was in a distant westerly direction, and those of the following cycles became progressively closer and more southerly, ending near the present position of the central and western Brooks Range. A collision between Alaska and Siberia in mid-Tertiary time initiated the Eurekan sequence of circum-arctic compressional tectonics. The North Slope block was tilted northeast, and the Nuwok cycle was derived from the resulting regional erosion. Similar tilting and erosion beginning in the Pleistocene started the Gubik cycle that is still being deposited.

Noonan, W.G.

1985-04-01

371

Estimation of streamflow by slope Regional Dependency Function  

Directory of Open Access Journals (Sweden)

Full Text Available Kriging is one of the most developed methodologies in the regional variable modeling. However, one of its drawbacks is that the influence radius can not be determined by this method. In which distance and in what ratio that pivot station is influenced from adjacent sites is rather often encountered problem in practical applications. Regional weighting functions obtained from available data consist of several broken lines. Each line has different slopes which represent the similarity and the contribution of adjacent stations as a weighting coefficient. The approach in this study is called as Slope Regional Dependency Function (SRDF). The main idea of this approach is to express the variability in value differences [?(d)] and distances together. Originally proposed SRDF and Trigonometric Point Cumulative Semi-Variogram (TPCSV) methods are used to predict streamflow. Also TPCSV and Point Cumulative Semi-Variogram (PCSV) approaches are compared with each other. Prediction performance of all three methods stays below 10% relative error which is acceptable for the engineering applications. It is shown that SRDF outperforms PCSV and TPCSV with very high differences. It can be used for missing data completion, determination of measurement sites location, calculation of influence radius, and determination of regional variable potential. The proposed method is applied for the 38 stream flow measurement sites located in the Mississippi River basin.

A. Altunkaynak

2008-01-01

372

Estimation of streamflow by slope regional dependency function  

Directory of Open Access Journals (Sweden)

Full Text Available Kriging is one of the most developed methodologies in the regional variable modeling. However, one of its drawbacks is that the influence radius can not be determined by this method. In which distance and in what ratio that pivot station is influenced from adjacent sites is rather often encountered problem in practical applications. Regional weighting functions obtained from available data consist of several broken lines. Each line has different slopes which represent the similarity and the contribution of adjacent stations as a weighting coefficient. The approach in this study is called as Slope Regional Dependency Function (SRDF). The main idea of this approach is to express the variability in value differences ? and distances together. Originally proposed SRDF and Trigonometric Point Cumulative Semi-Variogram (TPCSV) methods are used to predict streamflow. TPCSV and Point Cumulative Semi-Variogram (PCSV) approaches are also compared with each other. Prediction performance of all the three methods revealed a relative error less than 10% which is acceptable for most engineering applications. It is shown that SRDF outperforms PCSV and TPCSV with very high differences. It can be used for missing data completion, determination of measurement sites location, calculation of influence radius, and determination of regional variable potential. The proposed method is applied for the 38 stream flow measurement sites located in the Mississippi River basin.

A. Altunkaynak

2008-01-01

373

Precision Tiltmeter as a Reference for Slope MeasuringInstruments  

Energy Technology Data Exchange (ETDEWEB)

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).

Kirschman, Jonathan L.; Domning, Edward E.; Morrison, Gregory Y.; Smith, Brian V.; Yashchuk, Valeriy V.

2007-08-01

374

One slope or two? Detecting statistically significant breaks of slope in geophysical data, with application to fracture scaling relationships  

Science.gov (United States)

The scaling of displacement as a function of length is important for a variety of applications which depend on the mechanical and hydraulic properties of faults and fractures. Recently it has been suggested that the power-law exponent ? which has been found to characterise this relationship may change significantly at a characteristic length for a variety of reasons, for example when cracks begin to interact, or when faults grow to a length comparable to a characteristic size in the brittle layer. Such a break of slope requires a second straight line, requiring two extra model parameters. Here we present a new method for analysing such data, which penalises the extra parameters using a modified form of Schwarz's Information Criterion, and a Bayesian approach which represents uncertainty in the unknown parameters. We apply the method to data from the Krafla fissure zone in the north of Iceland, and find a significant break of slope, from ? ? 3/2 to ? ? 2/3, at a characteristic length of 12m.

Main, I. G.; Leonard, T.; Papasouliotis, O.; Hatton, C. G.; Meredith, P. G.

375

Short-term vegetation recovery after a spring grassland fire in Lithuania. Effect of time and slope position  

Directory of Open Access Journals (Sweden)

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.

P. Pereira; M. Pranskevicius; V. Cepanko; D. Vaitkute; N. Pundyte; X. Ubeda; J. Mataix-Solera; A. Cerdà; D. Martin

2013-01-01

376

Isotopic Variations in Permafrost on the North Slope of Alaska  

Science.gov (United States)

Anadarko Petroleum Corporation, Maurer Technology, and the U.S. Department of Energy drilled the Hot Ice #1 borehole on the North Slope of Alaska during March/April of 2003. Its purpose was to explore for the possible occurrence of methane hydrates in the base of the thick permafrost zone present on the North Slope. The borehole reached a depth of 425 m, passing through the bottom of the permafrost at about 380 m. The entire hole was cored, with core recovery exceeding 90%. The bedrock geology consists of interbedded sequences of siltstone, conglomerate, sandstone, coal and shale with some bitumens and/or ice lenses. The borehole represents an ideal opportunity to study geochemical signals present in the North Slope permafrost. Thirty samples, obtained over the entire length of the core, were collected for isotopic analyses and are currently being analyzed at the Center for Isotope Geochemistry at the Lawrence Berkeley National Laboratory. The samples were chosen to best determine whether any broad isotopic trends exist within the permafrost. Measurements are being made of the hydrogen and oxygen isotope ratios of the ice and the carbon isotope ratios of carbon dioxide trapped in the permafrost. In addition, the carbon isotope ratios of any methane contained in the samples will also be determined. Preliminary results for the oxygen isotope compositions of the permafrost yield ? 18O values ranging from -18‰ to -22‰ with a general trend towards lower values in the deeper part of the core. The concentrations of the CO2 in the samples (possibly representing dissolved inorganic carbon in the pore water?) range from 0.6 to 2.5 millimoles/liter with concentrations increasing with depth. The ? 13C values of the CO2 range from -7‰ to -27‰ with the lowest values in the higher concentration, deeper samples. This trend is consistent with increasing inputs of CO2 derived from hydrocarbons/hydrates with depth and may yield insight into the affecting methane hydrate formation within the permafrost.

Conrad, M. E.; Douglas, T. A.; Woods, K. N.

2003-12-01

377

The investigation and stability analysis of an excavated rock slope in the Daejin highway  

Energy Technology Data Exchange (ETDEWEB)

The stability analysis on the rock slope where the failures occurred in Daejin Highway was carried out using the stereo graphic projection analysis techniques and SMR (Slope Mass Rating) approach. The three major discontinuity sets were distributed and the block failures that were governed by the three sets of discontinuity were dominant in the slope face. In the rock slope mass rating for each discontinuity set, the minor SMR index showed 50.5 and the average rating value was 61.6 for the overall slope. This index represented class 11 and that the slope was 'stable'. In the slope of class II some block failures were expected. As rock slope can be easily weathered with exposure, the class of rock slope was be treated as class III. In a broad sense, the system of reinforcement such as spot or systematic bolting, shotcrete, toe ditch or net should be implemented to stabilize the slope. (author). 8 refs., 7 tabs., 10 figs.

Sunwoo, Choon; Chung, So-Keul; Shin, Hee-Soon [Korea Institute of Geology Mining and Materials, Taejon (Korea)

1999-12-01

378

T-wave sources, slopes, rough bottoms and continuum  

Science.gov (United States)

Bathymetry plays a strong role in the excitation of T-waves by breaking strict mode orthogonality and permitting energy from higher order modes to couple to the lower order modes comprising the T-phase. Observationally (Dziak, 2001) earthquakes with a strong strike-slip component are more efficient at generating T-waves than normal fault mechanisms with the same moment magnitude. It is shown that fault type and orientation correlates strongly with T-wave excitation efficiency. For shallow sources, the discrete modes contribute to the majority of the seismic source field, which is then scattered into the acoustic modes by irregular bathymetry. However, the deeper the earthquake source, the more important the continuum component of the spectrum becomes for the excitation. Deterministic bathymetry and random roughness enter the modal scattering theory as separate terms, and allow the relative contributions from the slope conversion mechanism and bottom roughness to be directly compared. [Work supported by the National Ocean Partnership Program.

Odom, Robert I.; Soukup, Darin J.

2002-05-01

379

Investigation of continuously variable slope delta modulator/demodulator compatibility  

Science.gov (United States)

A computer model of the continuously variable slope delta voice encoding system specified in the draft STANAG on "Analogue/Digital Conversion of Speech Signals for Tactical, Digital Area Communication Systems", dated June 1978, is developed and implemented in FORTRAN IV. The model's performance is then characterized in terms of idle channel noise, total harmonic distortion, intermodulation distortion, signal-to-noise ratio, and frequency response. For each of these attributes, the system's performance is presented graphically and compared to the criteria established in the draft standard. The model is then exercised by varying the system parameters to the limits imposed by the standard and the resulting performance compared to the previously determined ideal system performance. The results show that the performance characteristics measured are most sensitive to the primary integrator response and output filter response when the system parameters are restricted to the range allowed by the draft NATO standard.

Lersch, J. A.

1980-12-01

380

Biocorrosive thermophilic microbial communities in Alaskan North Slope oil facilities.  

UK PubMed Central (United Kingdom)

Corrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon, with standard treatment methods targeting mesophilic sulfate-reducing bacteria. In assessing biocorrosion potential at an Alaskan North Slope oil field, we identified thermophilic hydrogen-using methanogens, syntrophic bacteria, peptide- and 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 reinjected into reservoirs for oil recovery purposes, are biodegraded and can provide biocorrosive microbial communities with an important source of nutrients.

Duncan KE; Gieg LM; Parisi VA; Tanner RS; Tringe SG; Bristow J; Suflita JM

2009-10-01

 
 
 
 
381

Biocorrosive Thermophilic Microbial Communities in Alaskan North Slope Oil Facilities  

Energy Technology Data Exchange (ETDEWEB)

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.

Duncan, Kathleen E.; Gieg, Lisa M.; Parisi, Victoria A.; Tanner, Ralph S.; Green Tringe, Susannah; Bristow, Jim; Suflita, Joseph M.

2009-09-16

382

Maximal slope of tensor product of Hermitian vector bundles  

CERN Multimedia

We give an upper bound for the maximal slope of the tensor product of several non-zero Hermitian vector bundles on the spectrum of an algebraic integer ring. By Minkowski's theorem, we need to estimate the Arakelov degree of an arbitrary Hermitian line subbundle $\\bar M$ of the tensor product. In the case where the generic fiber of $M$ is semistable in the sense of geometric invariant theory, the estimation is established by constructing, through the classical invariant theory, a special polynomial which does not vanish on the generic fibre of $M$. Otherwise we use an explicte version of a result of Ramanan and Ramanathan to reduce the general case to the former one.

Chen, Huayi

2007-01-01

383

Monte-Carlo Modeling of Some Niger Delta Slope Events  

Directory of Open Access Journals (Sweden)

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.

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

2009-01-01

384

Research on the seasonal snow of the Arctic Slope  

Energy Technology Data Exchange (ETDEWEB)

This project deals with the seasonal snow on Alaska's Arctic Slope. Although it is concentrated on snow of the R{sub 4}D 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. The 1984--1985, 1985--1986 and 1986--1987 seasonal snow was measured to determine its total quantity, its physical structure and its distribution as a function of wind and topography. Observations of meteorological parameters and snowpack characteristics during winter and spring have yielded information on the seasonal evolution of the snow in quantitative terms. A method of determining melt rates over large regions was developed and is being refined, progress was made on a model describing energy flux sources which control snow melting. A strong control is exerted by air mass advection on a broad scale. We are continuing to devote attention to the sources of energy and energy transfer mechanisms which control snow melt. The 1986 snow melt was two weeks later than the 1987 and 1985 meltouts. The delay was caused by advection of cold air from the Arctic Ocean. When it did get underway melting was very rapid and the snow pack disappeared in only half the time taken in 1985.

Benson, C.S.

1988-01-01

385

[Vegetation and erosion control: exploration on basic principle of slope engineering  

UK PubMed Central (United Kingdom)

During its interaction with local climate and surface and shallow soil, vegetation appears to be of certain hydro-mechanical effects, and provides with some engineering properties on erosion control and slope protection. Slope eco-engineering integrates these properties with soil for slope protection projects. Along with the increasing awareness of the interactions between vegetation and soil and their significance in erosion control during the past few decades, this biological approach has been widely applied in physical environment improvement and engineered slope protection world wide. Some important contents in slope eco-engineering are the concept of "soil-vegetation system" and the related biological natures and engineering properties. The "soil-vegetation system" concept is a theoretical substance, and its eco-biological natures, engineering properties and some internal regulations are the theoretical hypothesis of the substance, which could be the basic materials for setting up the scientific principles of slope eco-engineering.

Zhou Y

2000-04-01

386

The role of the tibial slope in sustaining and treating anterior cruciate ligament injuries.  

UK PubMed Central (United Kingdom)

PURPOSE: A steep tibial slope may contribute to anterior cruciate ligament (ACL)-injuries, a higher degree of instability in the case of ACL insufficiency, and recurrent instability after ACL reconstruction. A better understanding of the significance of the tibial slope could improve the development of ACL injury screening and prevention programmes, might serve as a basis for individually adapted rehabilitation programmes after ACL reconstruction and could clarify the role of slope-decreasing osteotomies in the treatment of ACL insufficiency. This article summarizes and discusses the current published literature on these topics. METHODS: A comprehensive review of the MEDLINE database was carried out to identify relevant articles using multiple different keywords (e.g. 'tibial slope', 'anterior cruciate ligament', 'osteotomy', and 'knee instability'). The reference lists of the reviewed articles were searched for additional relevant articles. RESULTS: In cadaveric studies, an artificially increased tibial slope produced an anterior shift of the tibia relative to the femur. While mathematical models additionally demonstrated increased strain in the ACL, cadaveric studies have not confirmed these findings. There is some evidence that a steep tibial slope represents a risk factor for non-contact ACL injuries. MRI-based studies indicate that a steep slope of the lateral tibial plateau might specifically be responsible for this injury mechanism. The influence of the tibial slope on outcomes after ACL reconstruction and the role of slope-decreasing osteotomies in the treatment of ACL insufficiency remain unclear. CONCLUSION: The role of the tibial slope in sustaining and treating ACL injuries is not well understood. Characterizing the tibial plateau surface with a single slope measurement represents an insufficient approximation of its three-dimensionality, and the biomechanical impact of the tibial slope likely is more complex than previously appreciated. LEVEL OF EVIDENCE: IV.

Feucht MJ; Mauro CS; Brucker PU; Imhoff AB; Hinterwimmer S

2013-01-01

387

INFLUENCE OF HILLY TERRAIN SLOPE ON THE VOLUME OF ROAD EARTHWORK ??????? ???????????? ????????? ?? ?????? ???????? ???????? ?????  

Directory of Open Access Journals (Sweden)

Full Text Available The analytic dependence for slope correction calculation is obtained. This correction is introduced in the formula for calculating the area of earth roadbed cross-section. It allows detailing the volume of road earthwork at the design stage. The correction size depends on the slope steepness as well as cross-sectional parameters of the earth roadbed. The calculations show that the correction size is essential if ratio of slope is 25 or less

Morkovin V. A.; Kirillov F. A.

2012-01-01

388

The Prym map on divisors, and the slope of A_5  

CERN Multimedia

In this paper we compute the pullback of divisor classes under the Prym map (extended to the boundary), and apply this result to get a lower bound on the slope of effective divisors on the perfect cone compactification of the moduli space of principally polarized abelian fivefolds. In the appendix by Klaus Hulek, the notion of slope for arbitrary toroidal compactifications is discussed, and the slope bound is shown to hold in general.

Grushevsky, Samuel; Hulek, Klaus

2011-01-01

389

Geotechnical study and optimum pit slope design of the Ashok coal opencast project  

Energy Technology Data Exchange (ETDEWEB)

The paper deals with the geotechnical study and optimum ultimate pit slope design of Ashok opencast project with special reference to the highwalls ability of slopes created by surface miner. It was also aimed to know the influence of slope design parameters on the safety factor by sensitivity analysis. Geotechnical mapping was done on the exposed benches of the surface mine as per the norms of International Society of Rock Mechanics. The different geomechanical properties of lithological units were determined. The failure analysis was done by GALENA software based on limit equilibrium method and optimum slope design was recommended. 2 refs., 5 figs., 4 tabs.

Singh, V.K. [Central Institute of Mining and Fuel Research, Dhanbad (India)

2008-03-15

390

Determination of bench slope stability of an isotropic massif by means of computer calculations  

Energy Technology Data Exchange (ETDEWEB)

This article treats problems connected with designing slope angles which ensure sufficient slope stabilty at surface mines. Mathematical procedures and formulae are given which enable safe bench slopes for homogeneous isotropic media to be determined, applicable also in cases where a limited amount of data on the media are available. Method of subsequent approximation values for bench inclination angles and the methods were used for preventing bench sliding. Practical mathematical formulae and a table containing safe slope stability indexes are given (ranging from 0.551-1.326) for 15-30 m high benches inclined at 50-80 degrees. (3 refs.)

Zlatanov, P.; Kostov, T.

1982-04-01

391

Implication of errors for calculation results of surface mine slope stability  

Energy Technology Data Exchange (ETDEWEB)

This paper explains survey measurements of slope parameters conducted with the Koordimeter (Carl-Zeiss Jena) profile measuring instrument in the Trojanove 2 surface mine of the Maritza brown coal field. The instrument registers coordinates and the deviation of the real slope base line to the etalon base line of the instrument. These deviation values are used to determine the real bench shape, e.g. slope, heights and slope inclinations, more accurately. A table and a scheme of measurement results are provided. Parameters of the real bench shape were used to calculate the stability coefficient of the slope. It was found that stability calculation results with generalized slope parameters for a full bench length rather than with real bench parameters were inaccurate and required correction. The error for slope stability coefficients in various sections of the slope varied between 11.8% and -6.67%. The application of such bench measuring instruments is recommended in order to gain more reliable slope stability values in surface mines.

Stoeva, P.; Zlatanov, P.

1982-09-01

392

A new GTD slope diffraction coefficient for plane wave illumination of a wedge  

DEFF Research Database (Denmark)

Two wedge problems including slope diffraction are solved: one in which the incident field is a non-uniform plane wave, and one in which it is an inhomogeneous plane wave. The two solutions lead to the same GTD slope diffraction coefficient. This coefficient reveals the existence of a coupling effect between a transverse magnetic (or transverse electric) incident plane wave and the transverse electric (or transverse magnetic) slope-diffracted field. The coupling effect is not described by the existing GTD slope diffraction coefficient

Lumholt, Michael; Breinbjerg, Olav

1997-01-01

393

Stability of a natural slope under combined effects of reservoir water level drawdown and rainfall infiltration  

Energy Technology Data Exchange (ETDEWEB)

Several large-scale soil slopes were immersed when China's Three-Gorge reservoir was filled. The stability of these slopes during subsequent water level fluctuations is a public concern. For that reason, a series of transient seepage and slope stability analyses were performed to analyze the changes in the groundwater table in a landslide under the combined effects of reservoir water level drawdown and rainfall infiltration. The effects of gravel content in the slope soil on the groundwater regimes and the slope stability were also studied. The pore water pressures from these analyses were used for the stability analyses of the slope. The stability of the slope was found to decrease significantly when the reservoir level was lowered quickly during a rainstorm. This study also revealed that the infiltration rate is larger and the ground water level is higher in soil slopes with less gravel content, because the hydraulic conductivity of a soil with less gravel content is larger than that with higher gravel content when the soils are desaturated. It was concluded that the calculated factor of safety of the soil slope with less gravel content is smaller during rainfall. 21 refs., 1 tab., 8 figs.

Chen, Q. [Sichuan Univ., Chengdu, Sichuan (China). School of Hydraulic and Hydroelectric Engineering; Zhang, L. [Hong Kong Univ. of Science and Technology, Hong Kong (China). Dept. of Civil Engineering

2005-07-01

394

Sub-microradian surface slope metrology with the ALS Developmental Long Trace Profiler  

International Nuclear Information System (INIS)

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 also 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.

2010-05-01

395

Efficiency of Timber Jack 450C with Different Loading Volumes in Different Slopes  

Directory of Open Access Journals (Sweden)

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.

Majid Lotfalian; Hasan Sam Daliri; Yahya Kooch

2007-01-01

396

An emerging methodology of slope hazard assessment for natural gas pipelines  

Energy Technology Data Exchange (ETDEWEB)

A new slope assessment methodology has been developed by TransCanada PipeLines Ltd. in an effort to switch from a reactive to a proactive hazard management approach and to optimize maintenance expenditure. The company operates 37,000 km of natural gas gathering and transmission pipelines, portions of which traverse slopes and stream crossings. The newly developed rainfall-ground movement model provides site-specific ground movement predictions for approximately 1100 slopes and establishes a risk-ranked list of slopes upon which maintenance decisions can be based. The input to the predictive model is derived from internal and public information regarding site conditions. This information serves as input to a pipe-soil interaction model to determine the probability of pipeline failure for each slope. The ground movement for this model is limited to creep-type which is typically less than 100 mm per year. Landslides are not addressed in this paper. A system-wide database has been constructed for slopes to prioritize the slope movement hazards. The slope information includes geotechnical data such as bedrock geology, surficial geology, slope details, precipitation and erosion potential. Information related to the pipeline includes the location, age, size, as well as design pressure and temperature. 13 refs., 2 figs.

Zhou, Z.J.; O' Neil, G.; Rizkalla, M. [TransCanada PipeLines Ltd., Calgary, AB (Canada)

2000-07-01

397

Geotechnical characteristics and slope stability on the Ebro margin, western Mediterranean  

Science.gov (United States)

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.

Baraza, J.; Lee, H. J.; Kayen, R. E.; Hampton, M. A.

1990-01-01

398

Sub-microradian Surface Slope Metrology with the ALS Developmental Long Trace Profiler  

Energy Technology Data Exchange (ETDEWEB)

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 v